An ecological vegetation-activated sludge process (V-ASP) for decentralized wastewater treatment: system development, treatment performance, and mathematical modeling.

PubMed

Yuan, Jiajia; Dong, Wenyi; Sun, Feiyun; Li, Pu; Zhao, Ke

2016-05-01

An environment-friendly decentralized wastewater treatment process that is comprised of activated sludge process (ASP) and wetland vegetation, named as vegetation-activated sludge process (V-ASP), was developed for decentralized wastewater treatment. The long-term experimental results evidenced that the vegetation sequencing batch reactor (V-SBR) process had consistently stable higher removal efficiencies of organic substances and nutrients from domestic wastewater compared with traditional sequencing batch reactor (SBR). The vegetation allocated into V-SBR system could not only remove nutrients through its vegetation transpiration ratio but also provide great surface area for microorganism activity enhancement. This high vegetation transpiration ratio enhanced nutrients removal effectiveness from wastewater mainly by flux enhancement, oxygen and substrate transportation acceleration, and vegetation respiration stimulation. A mathematical model based on ASM2d was successfully established by involving the specific function of vegetation to simulate system performance. The simulation results on the influence of operational parameters on V-ASP treatment effectiveness demonstrated that V-SBR had a high resistance to seasonal temperature fluctuations and influent loading shocking.

Enhanced biological nutrient removal in sequencing batch reactors operated as static/oxic/anoxic (SOA) process.

PubMed

Xu, Dechao; Chen, Hongbo; Li, Xiaoming; Yang, Qi; Zeng, Tianjing; Luo, Kun; Zeng, Guangming

2013-09-01

An innovative static/oxic/anoxic (SOA) activated sludge process characterized by static phase as a substitute for conventional anaerobic stage was developed to enhance biological nutrient removal (BNR) with influent ammonia of 20 and 40 mg/L in R1 and R2 reactors, respectively. The results demonstrated that static phase could function as conventional anaerobic stage. In R1 lower influent ammonia concentration facilitated more polyphosphate accumulating organisms (PAOs) growth, but secondary phosphorus release occurred due to NOx(-) depletion during post-anoxic period. In R2, however, denitrifying phosphorus removal proceeded with sufficient NOx(-). Both R1 and R2 saw simultaneous nitrification-denitrification. Glycogen was utilized to drive post-denitrification with denitrification rates in excess of typical endogenous decay rates. The anoxic stirring duration could be shortened from 3 to 1.5h to avoid secondary phosphorus release in R1 and little adverse impact was found on nutrients removal in R2. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biogeochemical Hotspots: Role of Small Wetlands in Nutrient Processing at the Watershed Scale

NASA Astrophysics Data System (ADS)

Cheng, F. Y.; Basu, N. B.

2016-12-01

Increased loading of nutrients (nitrogen N and phosphorus P) from agricultural and urban intensification in the Anthropocene has led to severe degradation of inland and coastal waters. Amongst aquatic ecosystems, wetlands receive and retain significant quantities of nutrients and thus are important regulators of nutrient transport in watersheds. While the factors controlling N and P retention in wetlands is relatively well known, there is a lack of quantitative understanding on the relative contributions of the different factors on nutrient retention. There is also a deficiency in knowledge of how these processes behave across system size and type. In our study, we synthesized nutrient retention data from wetlands, lakes, and reservoirs to gain insight on the relationship between hydrologic and biogeochemical controls on nutrient retention. Our results indicated that the first-order reaction rate constant, k [T-1], is inversely proportional to the hydraulic residence time, τ, across six orders of magnitude in residence time for total nitrogen, total phosphorus, nitrate and phosphate. We hypothesized that the consistency of the relationship across constituent and system types points to the strong hydrologic control on biogeochemical processing. The hypothesis was tested using a two-compartment mechanistic model that links the nutrient removal processes (denitrification for N and sedimentation for P) with the system size. Finally, the k-τ relationships were upscaled with a regional size-frequency distribution to demonstrate the disproportionately large role of small wetlands in watershed-scale nutrient processing. Our results highlight the importance of hydrological controls as the dominant modifiers of nutrient removal mechanisms and the need for a stronger focus on small lentic ecosystems like wetlands as major nutrient sinks in the landscape.

Performance of a novel baffled osmotic membrane bioreactor-microfiltration hybrid system under continuous operation for simultaneous nutrient removal and mitigation of brine discharge.

PubMed

Pathak, Nirenkumar; Chekli, Laura; Wang, Jin; Kim, Youngjin; Phuntsho, Sherub; Li, Sheng; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Hokyong

2017-09-01

The present study investigated the performance of an integrated osmotic and microfiltration membrane bioreactor system for wastewater treatment employing baffles in the reactor. Thus, this reactor design enables both aerobic and anoxic processes in an attempt to reduce the process footprint and energy costs associated with continuous aeration. The process performance was evaluated in terms of water flux, salinity build up in the bioreactor, organic and nutrient removal and microbial activity using synthetic reverse osmosis (RO) brine as draw solution (DS). The incorporation of MF membrane was effective in maintaining a reasonable salinity level (612-1434mg/L) in the reactor which resulted in a much lower flux decline (i.e. 11.48-6.98LMH) as compared to previous studies. The stable operation of the osmotic membrane bioreactor-forward osmosis (OMBR-FO) process resulted in an effective removal of both organic matter (97.84%) and nutrient (phosphate 87.36% and total nitrogen 94.28%), respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparing Nutrient Removal from Membrane Filtered and Unfiltered Domestic Wastewater Using Chlorella vulgaris

PubMed Central

Mayhead, Elyssia; Llewellyn, Carole A.; Fuentes-Grünewald, Claudio

2018-01-01

The nutrient removal efficiency of Chlorella vulgaris cultivated in domestic wastewater was investigated, along with the potential to use membrane filtration as a pre-treatment tool during the wastewater treatment process. Chlorella vulgaris was batch cultivated for 12 days in a bubble column system with two different wastewater treatments. Maximum uptake of 94.18% ammonium (NH4-N) and 97.69% ortho-phosphate (PO4-P) occurred in 0.2 μm membrane filtered primary wastewater. Membrane filtration enhanced the nutrient uptake performance of C. vulgaris by removing bacteria, protozoa, colloidal particles and suspended solids, thereby improving light availability for photosynthesis. The results of this study suggest that growing C. vulgaris in nutrient rich membrane filtered wastewater provides an option for domestic wastewater treatment to improve the quality of the final effluent. PMID:29351200

Re-use of winery wastewaters for biological nutrient removal.

PubMed

Rodríguez, L; Villaseñor, J; Buendía, I M; Fernández, F J

2007-01-01

The aim of this study was to evaluate the feasibility of the re-use of the winery wastewater to enhance the biological nutrient removal (BNR) process. In batch experiments it was observed that the addition of winery wastewater mainly enhanced the nitrogen removal process because of the high denitrification potential (DNP), of about 130 mg N/g COD, of the contained substrates. This value is very similar to that obtained by using pure organic substrates such as acetate. The addition of winery wastewater did not significantly affect either phosphorus or COD removal processes. Based on the experimental results obtained, the optimum dosage to remove each mg of N-NO3 was determined, being a value of 6.7 mg COD/mg N-NO3. Because of the good properties of the winery wastewater to enhance the nitrogen removal, the viability of its continuous addition in an activated sludge pilot-scale plant for BNR was studied. Dosing the winery wastewater to the pilot plant a significant increase in the nitrogen removal was detected, from 58 to 75%. The COD removal was slightly increased, from 89 to 95%, and the phosphorus removal remained constant.

Effects of Sludge Retention Times on Nutrient Removal and Nitrous Oxide Emission in Biological Nutrient Removal Processes

PubMed Central

Li, Bo; Wu, Guangxue

2014-01-01

Sludge retention time (SRT) is an important factor affecting not only the performance of the nutrient removal and sludge characteristics, but also the production of secondary pollutants such as nitrous oxide (N2O) in biological nutrient removal (BNR) processes. Four laboratory-scale sequencing batch reactors (SBRs), namely, SBR5, SBR10, SBR20 and SBR40 with the SRT of 5 d, 10 d, 20 d and 40 d, respectively, were operated to examine effects of SRT on nutrient removal, activated sludge characteristics and N2O emissions. The removal of chemical oxygen demand or total phosphorus was similar under SRTs of 5–40 d, SRT mainly affected the nitrogen removal and the optimal SRT for BNR was 20 d. The molecular weight distribution of the effluent organic matters was in the range of 500–3,000 Da under SRTs of 5–40 d. The lowest concentration of the effluent soluble microbial products concentration was obtained at the SRT of 5 d. Nitrifier growth was limited at a short SRT and nitrite existed in the effluent of SBR5. With increasing SRTs, mixed liquor suspended solids concentration increased while the excess sludge production was reduced due to the high endogenous decay rate at high SRTs. Endogenous decay coefficients were 0.020 d−1, 0.036 d−1, 0.037 d−1 and 0.039 d−1 under SRTs of 5–40 d, respectively. In BNR, the N2O emission occurred mainly during the aerobic phase and its emission ratio decreased with increasing SRTs. The ratio between the N2O-N emission and the removed ammonium nitrogen in the aerobic phase was 5%, 3%, 1.8% and 0.8% at the SRT of 5 d, 10 d, 20 d and 40 d, respectively. With low concentrations of dissolved oxygen and high concentrations of oxidized nitrogen, the N2O emission was significantly accelerated due to heterotrophic denitrification activities. PMID:24681555

Instream Attenuation of Nitrogen and Phosphorus in Non-Point Source Dominated Streams: Hydrologic and Biogeochemical Controls

NASA Astrophysics Data System (ADS)

Bray, E. N.; Chen, X.; Keller, A. A.

2010-12-01

Non-point source inputs of total nitrogen (TN) and total phosphorus (TP) in rivers are the leading causes of water quality degradation in the United States (Turner and Rabalais, 2003; Broussard and Turner, 2009). Yet it remains a challenge to adequately quantify the relative role and influence of physical hydrological processes versus biogeochemical processes on the attenuation of TN and TP for individual river reaches. A watershed-scale study of instream dynamics and attenuation of TN and TP in northeastern U.S. headwater streams demonstrates that physical and hydrological processes exert greater control over nutrient removal than biogeochemical processes. To explore these interactions under various attenuation scenarios, we developed the watershed-scale model (WARMF) for 97 catchments to simulate watershed processes, hydrology, and diffuse source loads of nutrients. We simulated a hypothetical nutrient release at a rate of 1 kg/d of TN (50% as ammonium and 50% as nitrate) and TP (100% as phosphate) to predict response lengths of downstream catchments. Resulting attenuation factors are presented as the change in mean load at a given location, normalized to the change in the catchment in which the load is applied. Results indicate that for most catchments, the TN and TP load increase is attenuated from the stream within a few tens of kilometers. Fifty percent attenuation occurs across length scales ranging from a few hundreds of meters to kilometers if the load is introduced in the headwaters, indicating the most rapid nutrient removal occurs in the smallest headwater streams but generally decreases with distance downstream. There are some differences in the attenuation factors for TN and TP, although the pattern of attenuation is the same. Sensitivity analyses highlight five hydrological parameters of paramount importance to concentrations of N and P, namely precipitation, evaporation coefficients (magnitude and skewness), soil layer thickness, soil saturated moisture and soil hydraulic conductivity. These model parameters have a significant effect on the concentrations of nutrients, with TN exhibiting greater sensitivity. Further, attenuation results suggest that stream depth, flow regime, and density of agriculture in small headwater streams are potentially important controls to nutrient uptake and removal; i.e. during periods of low flow, dilution is reduced, attenuation length increases, and removal processes may be dominated by settling as opposed to biogeochemistry. Instream attenuation and model results can be used to assess 1) the scale and nature of best management practices which must be adopted to result in nutrient reductions, 2) the downstream distance at which load reductions will be effective, and 3) the hydrological characteristics of the river network which exert considerable influence on attenuation lengths and nutrient removal.

Effects of soluble and particulate substrate on the carbon and energy footprint of wastewater treatment processes.

PubMed

Gori, Riccardo; Jiang, Lu-Man; Sobhani, Reza; Rosso, Diego

2011-11-15

Most wastewater treatment plants monitor routinely carbonaceous and nitrogenous load parameters in influent and effluent streams, and often in the intermediate steps. COD fractionation discriminates the selective removal of VSS components in different operations, allowing accurate quantification of the energy requirements and mass flows for secondary treatment, sludge digestion, and sedimentation. We analysed the different effects of COD fractions on carbon and energy footprint in a wastewater treatment plant with activated sludge in nutrient removal mode and anaerobic digestion of the sludge with biogas energy recovery. After presenting a simple rational procedure for COD and solids fractions quantification, we use our carbon and energy footprint models to quantify the effects of varying fractions on carbon equivalent flows, process energy demand and recovery. A full-scale real process was modelled with this procedure and the results are reported in terms of energy and carbon footprint. For a given process, the increase of the ratio sCOD/COD increases the energy demand on the aeration reactors, the associated CO(2) direct emission from respiration, and the indirect emission for power generation. Even though it appears as if enhanced primary sedimentation is a carbon and energy footprint mitigation practice, care must be used since the nutrient removal process downstream may suffer from an excessive bCOD removal and an increased mean cell retention time for nutrient removal may be required. Copyright © 2011 Elsevier Ltd. All rights reserved.

Performance of the full-scale biological nutrient removal plant at Noosa in Queensland, Australia: nutrient removal and disinfection.

PubMed

Urbain, V; Wright, P; Thomas, M

2001-01-01

Stringent effluent quality guidelines are progressively implemented in coastal and sensitive areas in Australia. Biological Nutrient Removal (BNR) plants are becoming a standard often including a tertiary treatment for disinfection. The BNR plant in Noosa - Queensland is designed to produce a treated effluent with less than 5 mg/l of BOD5, 5 mg/l of total nitrogen, 1 mg/l of total phosphorus, 5 mg/l of suspended solids and total coliforms of less than 10/100 ml. A flexible multi-stage biological process with a prefermentation stage, followed by sand filtration and UV disinfection was implemented to achieve this level of treatment. Acetic acid is added for phosphorus removal because: i) the volatile fatty acids (VFA) concentration in raw wastewater varies a lot, and ii) the prefermenter had to be turned off due to odor problems on the primary sedimentation tanks. An endogenous anoxic zone was added to the process to further reduce the nitrate concentration. This resulted in some secondary P-release events, a situation that happens when low nitrate and low phosphorus objectives are targeted. Long-term performance data and specific results on nitrogen removal and disinfection are presented in this paper.

Biological nutrient removal and molecular biological characteristics in an anaerobic-multistage anaerobic/oxic (A-MAO) process to treat municipal wastewater.

PubMed

Huang, Xiao; Dong, Wenyi; Wang, Hongjie; Jiang, Shilong

2017-10-01

This study aimed to present an anaerobic-multistage anaerobic/oxic (A-MAO) process to treat municipal wastewater. The average COD, NH 4 + -N, TN, and TP removal efficiency were 91.81%, 96.26%, 83.73% and 94.49%, respectively. Temperature plunge and C/N decrease have a certain impact on the modified process. Characteristics of microbial community, function microorganism, and correlation of microbial community with environmental variables in five compartments were carried out by Illumina Miseq high-throughput sequencing. The differences of microbial community were observed and Blastocatella, Flavobacterium and Pseudomonas were the dominant genus. Nitrosomonas and Nitrospira occupied a dominant position in AOB and NOB, respectively. Rhodospirillaceae and Rhodocyclaceae owned a considerable proportion in phosphorus removal bacteria. DO and COD played significant roles on affecting the microbial components. The A-MAO process in this study demonstrated a high potential for nutrient removal from municipal wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of pilot high rate algal ponds for simultaneous nutrient removal and lipids production.

PubMed

Arbib, Zouhayr; de Godos, Ignacio; Ruiz, Jesús; Perales, José A

2017-07-01

Special attention is required to the removal of nitrogen and phosphorous in treated wastewaters. Although, there are a wide range of techniques commercially available for nutrient up-take, these processes entail high investment and operational costs. In the other hand, microalgae growth can simultaneously remove inorganic constituents of wastewater and produce energy rich biomass. Among all the cultivation technologies, High Rate Algae Ponds (HRAPs), are accepted as the most appropriate system. However, the optimization of the operation that maximizes the productivity, nutrient removal and lipid content in the biomass generated has not been established. In this study, the effect of two levels of depth and the addition of CO 2 were evaluated. Batch essays were used for the calculation of the kinetic parameters of microbial growth that determine the optimum conditions for continuous operation. Nutrient removal and lipid content of the biomass generated were analyzed. The best conditions were found at depth of 0.3m with CO 2 addition (biomass productivity of 26.2gTSSm -2 d -1 and a lipid productivity of 6.0glipidsm -2 d -1 ) in continuous mode. The concentration of nutrients was in all cases below discharge limits established by the most restrictive regulation for wastewater discharge. Copyright © 2017 Elsevier B.V. All rights reserved.

Growing Chlorella sp. on meat processing wastewater for nutrient removal and biomass production.

PubMed

Lu, Qian; Zhou, Wenguang; Min, Min; Ma, Xiaochen; Chandra, Ceria; Doan, Yen T T; Ma, Yiwei; Zheng, Hongli; Cheng, Sibo; Griffith, Richard; Chen, Paul; Chen, Chi; Urriola, Pedro E; Shurson, Gerald C; Gislerød, Hans R; Ruan, Roger

2015-12-01

In this work, Chlorella sp. (UM6151) was selected to treat meat processing wastewater for nutrient removal and biomass production. To balance the nutrient profile and improve biomass yield at low cost, an innovative algae cultivation model based on wastewater mixing was developed. The result showed that biomass yield (0.675-1.538 g/L) of algae grown on mixed wastewater was much higher than that on individual wastewater and artificial medium. Wastewater mixing eased the bottleneck for algae growth and contributed to the improved biomass yield. Furthermore, in mixed wastewater with sufficient nitrogen, ammonia nitrogen removal efficiencies (68.75-90.38%) and total nitrogen removal efficiencies (30.06-50.94%) were improved. Wastewater mixing also promoted the synthesis of protein in algal cells. Protein content of algae growing on mixed wastewater reached 60.87-68.65%, which is much higher than that of traditional protein source. Algae cultivation model based on wastewater mixing is an efficient and economical way to improve biomass yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nutrient removal and biogas upgrading by integrating freshwater algae cultivation with piggery anaerobic digestate liquid treatment.

PubMed

Xu, Jie; Zhao, Yongjun; Zhao, Guohua; Zhang, Hui

2015-08-01

An integrated approach that combined freshwater microalgae Scenedesmus obliquus (FACHB-31) cultivation with piggery anaerobic digestate liquid treatment was investigated in this study. The characteristics of algal growth, biogas production, and nutrient removal were examined using photobioreactor bags (PBRbs) to cultivate S. obliquus (FACHB-31) in digestate with various digestate dilutions (the concentration levels of 3200, 2200, 1600, 1200, 800, and 400 mg L(-1) chemical oxygen demand (COD)) during 7-day period. The effects of the level of pollutants on nutrient removal efficiency and CO2 removal process were investigated to select the optimum system for effectively upgrade biogas and simultaneously reduce the nutrient content in digestate. The treatment performance displayed that average removal rates of COD, total nitrogen (TN), total phosphorous (TP), and CO2 were 61.58-75.29, 58.39-74.63, 70.09-88.79, and 54.26-73.81 %, respectively. All the strains grew well under any the dilution treatments. With increased initial nutrient concentration to a certain range, the CO4 content (v/v) of raw biogas increased. Differences in the biogas enrichment of S. obliquus (FACHB-31) in all treatments mainly resulted from variations in biomass productivity and CO2 uptake. Notably, the diluted digestate sample of 1600 mg L(-1) COD provided an optimal nutrient concentration for S. obliquus (FACHB-31) cultivation, where the advantageous nutrient and CO2 removals, as well as the highest productivities of biomass and biogas upgrading, were revealed. Results showed that microalgal biomass production offered real opportunities to address issues such as CO2 sequestration, wastewater treatment, and biogas production.

Depletion and Redistribution of Soil Nutrients in Response to Wind Erosion in Desert Grasslands of the Southwestern United States

NASA Astrophysics Data System (ADS)

Li, J.; Okin, G.; Hartman, L.; Epstein, H.

2005-12-01

Wind is a key abiotic factor that determines the spatial distribution of soil nutrients in arid grasslands with large unvegetated gaps, such as those found in the southwestern US. On the landscape scale, basic relationships such as wind erosion rate vs. vegetative cover, and soil nutrient removal rate vs. vegetative cover have not yet been extensively studied. In a series of experiments conducted in the Jornada Experimental Range near Las Cruces, New Mexico, we have examined these relationships to determine the impact of wind erosion and dust emission on pools of soil nutrients. In the experiments, varying levels of cover were achieved by vegetation removal on 25 m x 50 m plots. Intense surface soil sampling was conducted to monitor spatial distribution of soil nutrients. Large numbers of aeolian sediment samplers were installed to obtain estimates of vertical and horizontal dust flux. Available data from one wind erosion season show that: 1) total organic C (TOC) and total N (TN) content in the windblown sediment collected at the height of 1 m were 2.2 to 7.2 times larger than those of nutrients in the surface soil (enrichment ratio); 2) enrichment ratio generally increases with the increase of vegetative cover, indicating biotic processes continually add nutrients to surface soil in high-cover treatments, while nutrients are depleted in low-cover treatments; 3) average horizontal mass flux is 12 times larger in the bare plot than in the control plot, indicating the extreme importance of vegetative cover in protecting soil nutrient loss caused by wind erosion; 4) detectable soil nutrient depletion happened within one windy season in plots with vegetation removal, especially for TOC and TN, reflecting the importance of biotic processes in maintaining nutrient pools in the surface soil; and, 5) after only a single windy season, wind erosion can significantly alter the spatial pattern of soil nutrients.

The Effects of Different External Carbon Sources on Nitrous Oxide Emissions during Denitrification in Biological Nutrient Removal Processes

NASA Astrophysics Data System (ADS)

Hu, Xiang; Zhang, Jing; Hou, Hongxun

2018-01-01

The aim of this study was to investigate the effects of two different external carbon sources (acetate and ethanol) on the nitrous oxide (N2O) emissions during denitrification in biological nutrient removal processes. Results showed that external carbon source significantly influenced N2O emissions during the denitrification process. When acetate served as the external carbon source, 0.49 mg N/L and 0.85 mg N/L of N2O was produced during the denitrificaiton processes in anoxic and anaerobic/anoxic experiments, giving a ratio of N2O-N production to TN removal of 2.37% and 4.96%, respectively. Compared with acetate, the amount of N2O production is negligible when ethanol used as external carbon addition. This suggested that ethanol is a potential alternative external carbon source for acetate from the point of view of N2O emissions.

Water recovery and solid waste processing for aerospace and domestic applications. Volume 2: Appendices

NASA Technical Reports Server (NTRS)

Murray, R. W.

1973-01-01

Water and sewage treatment systems are presented with concentration on the filtration of water. Equipment is described for organic removal, solids removal, nutrient removal, inorganic removal, and disinfection of the water. Such things as aseline hardware, additional piping connections, waste disposal, and costs involved are also reported.

The effect of primary sedimentation on full-scale WWTP nutrient removal performance.

PubMed

Puig, S; van Loosdrecht, M C M; Flameling, A G; Colprim, J; Meijer, S C F

2010-06-01

Traditionally, the performance of full-scale wastewater treatment plants (WWTPs) is measured based on influent and/or effluent and waste sludge flows and concentrations. Full-scale WWTP data typically have a high variance which often contains (large) measurement errors. A good process engineering evaluation of the WWTP performance is therefore difficult. This also makes it usually difficult to evaluate effect of process changes in a plant or compare plants to each other. In this paper we used a case study of a full-scale nutrient removing WWTP. The plant normally uses presettled wastewater, as a means to increase the nutrient removal the plant was operated for a period by-passing raw wastewater (27% of the influent flow). The effect of raw wastewater addition has been evaluated by different approaches: (i) influent characteristics, (ii) design retrofit, (iii) effluent quality, (iv) removal efficiencies, (v) activated sludge characteristics, (vi) microbial activity tests and FISH analysis and, (vii) performance assessment based on mass balance evaluation. This paper demonstrates that mass balance evaluation approach helps the WWTP engineers to distinguish and quantify between different strategies, where others could not. In the studied case, by-passing raw wastewater (27% of the influent flow) directly to the biological reactor did not improve the effluent quality and the nutrient removal efficiency of the WWTP. The increase of the influent C/N and C/P ratios was associated to particulate compounds with low COD/VSS ratio and a high non-biodegradable COD fraction. Copyright 2010 Elsevier Ltd. All rights reserved.

Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis.

PubMed

Zhou, Qiongzhi; Li, Feng; Ge, Fei; Liu, Na; Kuang, Yangduo

2016-10-01

Toxicants are generally harmful to biotechnology in wastewater treatment. However, trace toxicant can induce microbial hormesis, but to date, it is still unknown how this phenomenon affects nutrient removal during municipal wastewater treatment process. Therefore, this study focused on the effects of hormesis induced by cetyltrimethyl ammonium bromide (CTAB), a representative quaternary ammonium cationic surfactant, on nutrient removal by Chlorella vulgaris F1068. Results showed that when the concentration of CTAB was less than 10 ng/L, the cellular components chlorophyll a, proteins, polysaccharides, and total lipids increased by 10.11, 58.17, 38.78, and 11.87 %, respectively, and some enzymes in nutrient metabolism of algal cells, such as glutamine synthetase (GS), acid phosphatase (ACP), H(+)-ATPase, and esterase, were also enhanced. As a result, the removal efficiencies of ammonia nitrogen (NH4 (+)) and total phosphorus (TP) increased by 14.66 and 8.51 %, respectively, compared to the control during a 7-day test period. The underlying mechanism was mainly due to an enhanced photosynthetic activity of C. vulgaris F1068 indicated by the increase in chlorophyll fluorescence parameters (the value of Fv/Fm, ΦII, Fv/Fo, and rETR increased by 12.99, 7.56, 25.59, and 8.11 %, respectively) and adenylate energy charge (AEC) (from 0.68 to 0.72). These results suggest that hormesis induced by trace toxicants could enhance the nutrient removal, which would be further considered in the design of municipal wastewater treatment processes. Graphical abstract The schematic mechanism of C. vulgaris F1068 under CTAB induced hormesis. Green arrows ( ) represent the increase and the red arrow ( ) represents the decrease.

Anaerobic/oxic/anoxic granular sludge process as an effective nutrient removal process utilizing denitrifying polyphosphate-accumulating organisms.

PubMed

Kishida, Naohiro; Kim, Juhyun; Tsuneda, Satoshi; Sudo, Ryuichi

2006-07-01

In a biological nutrient removal (BNR) process, the utilization of denitrifying polyphosphate-accumulating organisms (DNPAOs) has many advantages such as effective use of organic carbon substrates and low sludge production. As a suitable process for the utilization of DNPAOs in BNR, an anaerobic/oxic/anoxic granular sludge (AOAGS) process was proposed in this study. In spite of performing aeration for nitrifying bacteria, the AOAGS process can create anaerobic/anoxic conditions suitable for the cultivation of DNPAOs because anoxic zones exist inside the granular sludge in the oxic phase. Thus, DNPAOs can coexist with nitrifying bacteria in a single reactor. In addition, the usability of DNPAOs in the reactor can be improved by adding the anoxic phase after the oxic phase. These characteristics enable the AOAGS process to attain effective removal of both nitrogen and phosphorus. When acetate-based synthetic wastewater (COD: 600 mg/L, NH4-N: 60 mg/L, PO(4)-P: 10 mg/L) was supplied to a laboratory-scale sequencing batch reactor under the operation of anaerobic/oxic/anoxic cycles, granular sludge with a diameter of 500 microm was successfully formed within 1 month. Although the removal of both nitrogen and phosphorus was almost complete at the end of the oxic phase, a short anoxic period subsequent to the oxic phase was necessary for further removal of nitrogen and phosphorus. As a result, effluent concentrations of NH(4)-N, NO(x)-N and PO(4)-P were always lower than 1 mg/L. It was found that penetration depth of oxygen inside the granular sludge was approximately 100 microm by microsensor measurements. In addition, from the microbiological analysis by fluorescence in situ hybridization, existence depth of polyphosphate-accumulating organisms was further than the maximum oxygen penetration depth. The water quality data, oxygen profiles and microbial community structure demonstrated that DNPAOs inside the granular sludge may be responsible for denitrification in the oxic phase, which enables effective nutrient removal in the AOAGS process.

Mathematical modelling of the influenced of diffusion rate on macro nutrient availability in paddy field

NASA Astrophysics Data System (ADS)

Renny; Supriyanto

2018-04-01

Nutrition is the chemical compounds that needed by the organism for the growth process. In plants, nutrients are organic or inorganic compounds that are absorbed from the roots of the soil. It consist of macro and micro nutrient. Macro nutrients are nutrition that needed by plants in large quantities, such as, nitrogen, calcium, pottacium, magnesium, and sulfur. The total soil nutrient is the difference between the input nutrient and the output nutrients. Input nutrients are nutrient that derived from the decomposition of organic substances. Meanwhile, the output nutrient consists of the nutrients that absorbed by plant roots (uptake), the evaporated nutrients (volatilized) and leached nutrients. The nutrient transport can be done through diffusion process. The diffusion process is essential in removing the nutrient from one place to the root surface. It will cause the rate of absorption of nutrient by the roots will be greater. Nutrient concept in paddy filed can be represented into a mathematical modelling, by making compartment models. The rate of concentration change in the compartment model forms a system of homogeneous linear differential equations. In this research, we will use Laplaces transformation to solve the compartment model and determined the dynamics of macro nutrition due to diffusion process.

An innovative symbiotic microalgae-IFAS process for nutrient removal and photo-oxygenation: Multi-scale investigations using microelectrodes and next-generation molecular tools

EPA Science Inventory

A consortium of algae and bacteria is known to be effective in removing nitrogen (N) and phosphorus (P) from wastewater; however, the concept has largely been limited to suspended processes and fixed filmed (biofilm) processes have not fully been explored. Here we demonstrate the...

Influence of pathogenic bacterial activity on growth of Scenedesmus sp. and removal of nutrients from public market wastewater.

PubMed

Al-Gheethi, A A; Mohamed, R M; Jais, N M; Efaq, A N; Abd Halid, Abdullah; Wurochekke, A A; Amir-Hashim, M K

2017-10-01

The present study aims to investigate the influence of Staphylococcus aureus, Escherichia coli and Enterococcus faecalis in public market wastewater on the removal of nutrients in terms of ammonium (NH 4 - ) and orthophosphate (PO 4 3 ) using Scenedesmus sp. The removal rates of NH 4 - and orthophosphate PO 4 3- and batch kinetic coefficient of Scenedesmus sp. were investigated. The phycoremediation process was carried out at ambient temperature for 6 days. The results revealed that the pathogenic bacteria exhibited survival potential in the presence of microalgae but they were reduced by 3-4 log at the end of the treatment process. The specific removal rates of NH 4 - and PO 4 3- have a strong relationship with initial concentration in the public market wastewater (R 2 = 0.86 and 0.80, respectively). The kinetic coefficient of NH 4 - removal by Scenedesmus sp. was determined as k = 4.28 mg NH 4 - 1 log 10 cell mL -1 d -1 and k m = 52.01 mg L -1 (R 2 = 0.94) while the coefficient of PO 4 3- removal was noted as k = 1.09 mg NH 4 - 1 log 10 cell mL -1 d -1 and k m = 85.56 mg L -1 (R 2 = 0.92). It can be concluded that Scenedesmus sp. has high competition from indigenous bacteria in the public market wastewater to remove nutrients, with a higher coefficient of removal of NH 4 - than PO 4 3 .

SITE EMERGING TECHNOLOGY SUMMARY. BIOSCRUBBER FOR REMOVING HAZARDOUS ORGANIC EMISSIONS FROM SOIL, WATER, AND AIR DECONTAMINATION PROCESSES

EPA Science Inventory

An advanced biofiltration system has been developed for the removal of trace organic contaminants in air. This bioscrubber uses activated carbon as a support for biogrowth. An advanced engineering design was incorporated into the bioscrubber to allow biomass removal and nutrient ...

Switchgrass cultivar, yield, and nutrient removal responses to harvest timing

USDA-ARS?s Scientific Manuscript database

Finite nutrients, such as P (phosphorus) and K (potassium) are remobilized post-growing season in herbaceous feedstocks such as swichgrass (Panicum virgatum L.) as a function of environmental signaling and genotype. However, harvesting early during the maturation process may result in yield reductio...

Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

PubMed

Liu, Junzhuo; Vyverman, Wim

2015-03-01

The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

Simultaneous attenuation of pharmaceuticals, organic matter, and nutrients in wastewater effluent through managed aquifer recharge: Batch and column studies.

PubMed

Im, Huncheol; Yeo, Inseol; Maeng, Sung Kyu; Park, Chul Hwi; Choi, Heechul

2016-01-01

Batch and column experiments were conducted to evaluate the removal of organic matter, nutrients, and pharmaceuticals and to identify the removal mechanisms of the target contaminants. The sands used in the experiments were obtained from the Youngsan River located in South Korea. Neutral and cationic pharmaceuticals (iopromide, estrone, and trimethoprim) were removed with efficiencies greater than 80% from different sand media during experiments, due to the effect of sorption between sand and pharmaceuticals. However, the anionic pharmaceuticals (sulfamethoxazole, ketoprofen, ibuprofen, and diclofenac) were more effectively removed by natural sand, compared to baked sand. These observations were mainly attributed to biodegradation under natural conditions of surface organic matter and ATP concentrations. The removal of organic matter and nitrogen was also found to increase under biotic conditions. Therefore, it is indicated that biodegradation plays an important role and act as major mechanisms for the removal of organic matter, nutrients, and selected pharmaceuticals during sand passage and the managed aquifer recharge, which is an effective treatment method for removing target contaminants. However, the low removal efficiencies of pharmaceuticals (e.g., carbamazepine and sulfamethoxazole) require additional processes (e.g., AOPs, NF and RO membrane), a long residence time, and long travel distance for increasing the removal efficiencies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of nonnative feral pig removal on soil structure and nutrient availability in Hawaiian tropical montane wet forests

Treesearch

Michael S. Long; Creighton M. Litton; Christian P. Giardina; Jonathan Deenik; Rebecca J. Cole; Jed P. Sparks

2017-01-01

Conservation and restoration of ecosystems impacted by nonnative ungulates increasingly involves their removal and exclusion. While the influence of nonnative ungulate removal on plant communities is commonly monitored, impacts on underlying ecological processes are seldom quantified. Here we examined how nonnative feral pig (

Improving the two-step remediation process for CCA-treated wood. Part II, Evaluating bacterial nutrient sources

Treesearch

Carol A. Clausen

2004-01-01

Remediation processes for recovery and reuse of chromated-copper-arsenate-(CCA) treated wood are not gaining wide acceptance because they are more expensive than landfill disposal. One reason is the high cost of the nutrient medium used to culture the metal tolerant bacterium, Bacillus licheniformis, which removes 70-100% of the copper, chromium, and arsenic from CCA-...

Biological nutrient removal with limited organic matter using a novel anaerobic–anoxic/oxic multi-phased activated sludge process

PubMed Central

Naseer, Rusul; Abualhail, Saad; Xiwu, Lu

2012-01-01

An anaerobic–anoxic/oxic (A2/O) multi-phased biological process called “phased isolation tank step feed technology (PITSF)” was developed to force the oscillation of organic and nutrient concentrations in process reactors. PITSF can be operated safely with a limited carbon source in terms of low carbon requirements and aeration costs whereas NAR was achieved over 95% in the last aerobic zone through a combination of short HRT and low DO levels. PCR assay was used for XAB quantification to correlate XAB numbers with nutrient removal. PCR assays showed, high NAR was achieved at XAB population 5.2 × 108 cells/g MLVSS in response to complete and partial nitrification process. It was exhibited that low DO with short HRT promoted XAB growth. Simultaneous nitrification and denitrification (SND) via nitrate were observed obviously, SND rate was between 69–72%, at a low DO level of 0.5 mg/l in the first aerobic tank during main phases and the removal efficiency of TN, NH4+-N, COD, TP was 84.7 .97, 88.3 and 96% respectively. The removal efficiencies of TN, NH4+-N, and TP at low C/N ratio and DO level were 84.2, 98.5 and 96.9% respectively which were approximately equal to the complete nitrification–denitrification with the addition of external carbon sources at a normal DO level of (1.5–2.5 mg/l). PMID:23961214

Source Separation of Urine as an Alternative Solution to Nutrient Management in Biological Nutrient Removal Treatment Plants.

PubMed

Jimenez, Jose; Bott, Charles; Love, Nancy; Bratby, John

2015-12-01

Municipal wastewater contains a mixture of brown (feces and toilet paper), yellow (urine), and gray (kitchen, bathroom and wash) waters. Urine contributes approximately 70-80% of the nitrogen (N), 50-70% of the phosphorus (P) load and 60-70% of the pharmaceutical residues in normal domestic sewage. This study evaluated the impact of different levels of source separation of urine on an existing biological nutrient removal (BNR) process. A process model of an existing biological nutrient removal (BNR) plant was used. Increasing the amount of urine diverted from the water reclamation facilities, has little impact on effluent ammonia (NH₃-N) concentration, but effluent nitrate (NO₃-N) concentration decreases. If nitrification is necessary then no reduction in the sludge age can be realized. However, a point is reached where the remaining influent nitrogen load matches the nitrogen requirements for biomass growth, and no residual nitrogen needs to be nitrified. That allows a significant reduction in sludge age, implying reduced process volume requirements. In situations where nitrification is required, lower effluent nitrate (NO₃-N) concentrations were realized due to both the lower influent nitrogen content in the wastewater and a more favorable nitrogen-to-carbon ratio for denitrification. The external carbon requirement for denitrification decreases as the urine separation efficiency increases due to the lower influent nitrogen content in the wastewater and a more favorable nitrogen-to-carbon ratio for denitrification. The effluent phosphorus concentration decreases when the amount of urine sent to water reclamation facilities is decreased due to lower influent phosphorus concentrations. In the case of chemical phosphate removal, urine separation reduces the amount of chemicals required.

Biological nutrient removal by internal circulation upflow sludge blanket reactor after landfill leachate pretreatment.

PubMed

Abood, Alkhafaji R; Bao, Jianguo; Abudi, Zaidun N

2013-10-01

The removal of biological nutrient from mature landfill leachate with a high nitrogen load by an internal circulation upflow sludge blanket (ICUSB) reactor was studied. The reactor is a set of anaerobic-anoxic-aerobic (A2/O) bioreactors, developed on the basis of an expended granular sludge blanket (EGSB), granular sequencing batch reactor (GSBR) and intermittent cycle extended aeration system (ICEAS). Leachate was subjected to stripping by agitation process and poly ferric sulfate coagulation as a pretreatment process, in order to reduce both ammonia toxicity to microorganisms and the organic contents. The reactor was operated under three different operating systems, consisting of recycling sludge with air (A2/O), recycling sludge without air (low oxygen) and a combination of both (A2/O and low oxygen). The lowest effluent nutrient levels were realised by the combined system of A2/O and low oxygen, which resulted in effluent of chemical oxygen demand (COD), NH3-N and biological oxygen demand (BOD5) concentrations of 98.20, 13.50 and 22.50 mg/L. The optimal operating conditions for the efficient removal of biological nutrient using the ICUSB reactor were examined to evaluate the influence of the parameters on its performance. The results showed that average removal efficiencies of COD and NH3-N of 96.49% and 99.39%, respectively were achieved under the condition of a hydraulic retention time of 12 hr, including 4 hr of pumping air into the reactor, with dissolved oxygen at an rate of 4 mg/L and an upflow velocity 2 m/hr. These combined processes were successfully employed and effectively decreased pollutant loading.

Promoting nitrate removal in rain gardens | Science Inventory ...

EPA Pesticide Factsheets

Rain gardens are vegetated surface depressions, often located at low points in landscapes, designed to receive stormwater runoff from roads, roofs, and parking lots. The gardens’ sandy soils allow stormwater to drain quickly to the native soils below and eventually to groundwater. The rain garden vegetation and soils remove pollutants and nutrients from stormwater runoff through biological and physical processes such as plant uptake and sorption to soil particles. In comparison with stormwater release to receiving waters through conventional storm drain systems, infiltrating stormwater through rain gardens reduces peak flows and loadings of both pollutants and nutrients. This reduction improves the physical and biological integrity of receiving streams by reducing stream bank erosion and negative effects on stream communities. While local governments and individual homeowners are building these systems, relatively few scientific studies have documented the ability of rain gardens to remove pollutants and nutrients. This U.S. EPA long-term research project investigates: 1) the performance of rain gardens in removing pollutants, and 2) whether currently-accepted design standards can be adjusted to improve nitrate removal capabilities. Typical rain garden designs provide large removals of pollutants of concern, including heavy metals, phosphorus, total nitrogen, and ammonium. The gardens have been less successful in removing nitrate, an importan

Habitat-specific nutrient removal and release in Oregon salt marshes

EPA Science Inventory

Wetlands can be sources, sinks and transformers of nutrients, although it is their role in nutrient removal that is valued as a water purification ecosystem service. In order to quantify that service for any wetland, it is important to understand the drivers of nutrient removal w...

Enhanced nitrogen removal from piggery wastewater with high NH4+ and low COD/TN ratio in a novel upflow microaerobic biofilm reactor.

PubMed

Meng, Jia; Li, Jiuling; Li, Jianzheng; Antwi, Philip; Deng, Kaiwen; Nan, Jun; Xu, Pianpian

2018-02-01

To enhance nutrient removal more cost-efficiently in microaerobic process treating piggery wastewater characterized by high ammonium (NH 4 + -N) and low chemical oxygen demand (COD) to total nitrogen (TN) ratio, a novel upflow microaerobic biofilm reactor (UMBR) was constructed and the efficiency in nutrient removal was evaluated with various influent COD/TN ratios and reflux ratios. The results showed that the biofilm on the carriers had increased the biomass in the UMBR and enhanced the enrichment of slow-growth-rate bacteria such as nitrifiers, denitrifiers and anammox bacteria. The packed bed allowed the microaerobic biofilm process perform well at a low reflux ratio of 35 with a NH 4 + -N and TN removal as high as 93.1% and 89.9%, respectively. Compared with the previously developed upflow microaerobic sludge reactor, the UMBR had not changed the dominant anammox approach to nitrogen removal, but was more cost-efficiently in treating organic wastewater with high NH 4 + -N and low COD/TN ratio. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of light presence and biomass concentration on nutrient kinetic removal from urban wastewater by Scenedesmus obliquus.

PubMed

Ruiz, J; Arbib, Z; Alvarez-Díaz, P D; Garrido-Pérez, C; Barragán, J; Perales, J A

2014-05-20

This work was aimed at studying the effect of light-darkness and high-low biomass concentrations in the feasibility of removing nitrogen and phosphorus from urban treated wastewater by the microalga Scenedesmus obliquus. Laboratory experiments were conducted in batch, where microalgae were cultured under different initial biomass concentrations (150 and 1500mgSSl(-1)) and light conditions (dark or illuminated). Nutrient uptake was more dependent on internal nutrient content of the biomass than on light presence or biomass concentration. When a maximum nitrogen or phosphorus content in the biomass was reached (around 8% and 2%, respectively), the removal of that nutrient was almost stopped. Biomass concentration affected more than light presence on the nutrient removal rate, increasing significantly with its increase. Light was only required to remove nutrients when the maximum nutrient storage capacity of the cells was reached and further growth was therefore needed. Residence times to maintain a stable biomass concentration, avoiding the washout of the reactor, were much higher than those needed to remove the nutrients from the wastewater. This ability to remove nutrients in the absence of light could lead to new configurations of reactors aimed to wastewater treatment. Copyright © 2014 Elsevier B.V. All rights reserved.

A new phosphate-selective sorbent for the Rem Nut process. Laboratory investigation and field experience at a medium size wastewater treatment plant.

PubMed

Petruzzelli, D; De Florio, L; Dell'Erba, A; Liberti, L; Notarnicola, M; Sengupta, A K

2003-01-01

P-control technologies for municipal wastewater are essentially based on "destructive" methods, that lead to formation of concentrated solid-phases (sludge), usually disposed-off in controlled landfills. Ion exchange, as a "non-destructive" technology, allows for selective removal and simultaneous recovery of pollutants, which can be recycled to the same and/or related productive lines. In this context, the REM NUT process removes nutrient species (HPO4 = , NH4+, K+) present in biologically oxidised municipal effluents and recovers them in the form of struvites (MgNH4PO4; MgKPO4), premium quality slow release fertilisers. The main limitation to the extensive application of this ion exchange based process is the non-availability of selective exchangers for specific removal of nutrient species. This paper illustrates laboratory investigation and pilot scale development of a so-called "P-driven" modified REM NUT scheme based on a new phosphate-selective sorbent developed at Lehigh University, PA, USA.

Does the combination of biochar and clinoptilolite enhance nutrient recovery from the liquid fraction of biogas digestate?

PubMed

Kocatürk-Schumacher, Nazlı Pelin; Zwart, Kor; Bruun, Sander; Brussaard, Lijbert; Jensen, Lars Stoumann

2017-05-01

Concentrating nutrients on biochar and clinoptilolite and subsequently using the nutrient-enriched sorbents as a fertiliser could be an alternative way to manage nutrients in digestate. In this study, we investigated the use of biochar and clinoptilolite columns in removing ammonium, potassium, orthophosphate and dissolved organic carbon (DOC) from the liquid fraction of digestate. Our objectives were to investigate the effect of the initial loading ratio between liquid and biochar on nutrient removal, and to investigate the effect of combining biochar with clinoptilolite on nutrient and DOC removal efficiency. Increasing the initial loading ratios increased nutrient concentrations on biochar to 8.61 mg NH 4 -N g -1 , 1.95 mg PO 4 -P g -1 and 13.01 mg DOC g -1 , but resulted in decreasing removal efficiencies. The combination of biochar and clinoptilolite resulted in improved ammonium, potassium and DOC removal efficiencies compared to biochar alone, but did not significantly change PO 4 -P removal efficiencies. Removal efficiencies with combined sorbents were up to 67% for ammonium, 58% for DOC and 58% for potassium. Clinoptilolite showed higher removal efficiencies compared to biochar alone, and combining clinoptilolite with biochar improved only total P removal efficiency. Concentrating nutrients with clinoptilolite and biochar may be an option when both sorbents are available at low cost.

Comparison of Habitat-Specific Nutrient Removal and Release in Pacific NW Salt Marshes at Multiple Spatial Scales

EPA Science Inventory

Wetlands can be sources, sinks and transformers of nutrients, although it is their role in nutrient removal that is valued as a water purification ecosystem service. In order to quantify that service for any wetland, it is important to understand the drivers of nutrient removal w...

Rain Garden Research at EPA’s Urban Watershed Research Facility: Promoting Nitrate Removal through Rain Garden Design

EPA Science Inventory

Rain gardens are designed to infiltrate stormwater, capture suspended solids, sorb heavy metals and phosphorus, and transform nutrients through biological processes. Most studies have found a low capacity for stormwater nitrate removal. Research at the Urban Watershed Managemen...

Advanced nutrient removal from surface water by a consortium of attached microalgae and bacteria: A review.

PubMed

Liu, Junzhuo; Wu, Yonghong; Wu, Chenxi; Muylaert, Koenraad; Vyverman, Wim; Yu, Han-Qing; Muñoz, Raúl; Rittmann, Bruce

2017-10-01

Innovative and cost-effective technologies for advanced nutrient removal from surface water are urgently needed for improving water quality. Conventional biotechnologies, such as ecological floating beds, or constructed wetlands, are not effective in removing nutrients present at low-concentration. However, microalgae-bacteria consortium is promising for advanced nutrient removal from wastewater. Suspended algal-bacterial systems can easily wash out unless the hydraulic retention time is long, attached microalgae-bacteria consortium is more realistic. This critical review summarizes the fundamentals and status of attached microalgae-bacteria consortium for advanced nutrient removal from surface water. Key advantages are the various nutrient removal pathways, reduction of nutrients to very low concentration, and diversified photobioreactor configurations. Challenges include poor identification of functional species, poor control of the community composition, and long start-up times. Future research should focus on the selection and engineering of robust microbial species, mathematical modelling of the composition and functionality of the consortium, and novel photobioreactor configurations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultra-processed foods and the limits of product reformulation.

PubMed

Scrinis, Gyorgy; Monteiro, Carlos Augusto

2018-01-01

The nutritional reformulation of processed food and beverage products has been promoted as an important means of addressing the nutritional imbalances in contemporary dietary patterns. The focus of most reformulation policies is the reduction in quantities of nutrients-to-limit - Na, free sugars, SFA, trans-fatty acids and total energy. The present commentary examines the limitations of what we refer to as 'nutrients-to-limit reformulation' policies and practices, particularly when applied to ultra-processed foods and drink products. Beyond these nutrients-to-limit, there are a range of other potentially harmful processed and industrially produced ingredients used in the production of ultra-processed products that are not usually removed during reformulation. The sources of nutrients-to-limit in these products may be replaced with other highly processed ingredients and additives, rather than with whole or minimally processed foods. Reformulation policies may also legitimise current levels of consumption of ultra-processed products in high-income countries and increased levels of consumption in emerging markets in the global South.

Application of electrochemical processes to membrane bioreactors for improving nutrient removal and fouling control.

PubMed

Borea, Laura; Naddeo, Vincenzo; Belgiorno, Vincenzo

2017-01-01

Membrane bioreactor (MBR) technology is becoming increasingly popular as wastewater treatment due to the unique advantages it offers. However, membrane fouling is being given a great deal of attention so as to improve the performance of this type of technology. Recent studies have proven that the application of electrochemical processes to MBR represents a promising technological approach for membrane fouling control. In this work, two intermittent voltage gradients of 1 and 3 V/cm were applied between two cylindrical perforated electrodes, immersed around a membrane module, at laboratory scale with the aim of investigating the treatment performance and membrane fouling formation. For comparison purposes, the reactor also operated as a conventional MBR. Mechanisms of nutrient removal were studied and membrane fouling formation evaluated in terms of transmembrane pressure variation over time and sludge relative hydrophobicity. Furthermore, the impact of electrochemical processes on transparent exopolymeric particles (TEP), proposed as a new membrane fouling precursor, was investigated in addition to conventional fouling precursors such as bound extracellular polymeric substances (bEPS) and soluble microbial products (SMP). All the results indicate that the integration of electrochemical processes into a MBR has the advantage of improving the treatment performance especially in terms of nutrient removal, with an enhancement of orthophosphate (PO 4 -P) and ammonia nitrogen (NH 4 -N) removal efficiencies up to 96.06 and 69.34 %, respectively. A reduction of membrane fouling was also observed with an increase of floc hydrophobicity to 71.72 %, a decrease of membrane fouling precursor concentrations, and, thus, of membrane fouling rates up to 54.33 %. The relationship found between TEP concentration and membrane fouling rate after the application of electrochemical processes confirms the applicability of this parameter as a new membrane fouling indicator.

Carbon and nitrogen dynamics and greenhouse gas emissions in constructed wetlands treating wastewater: a review

NASA Astrophysics Data System (ADS)

Jahangir, M. M. R.; Richards, K. G.; Healy, M. G.; Gill, L.; Müller, C.; Johnston, P.; Fenton, O.

2016-01-01

The removal efficiency of carbon (C) and nitrogen (N) in constructed wetlands (CWs) is very inconsistent and frequently does not reveal whether the removal processes are due to physical attenuation or whether the different species have been transformed to other reactive forms. Previous research on nutrient removal in CWs did not consider the dynamics of pollution swapping (the increase of one pollutant as a result of a measure introduced to reduce a different pollutant) driven by transformational processes within and around the system. This paper aims to address this knowledge gap by reviewing the biogeochemical dynamics and fate of C and N in CWs and their potential impact on the environment, and by presenting novel ways in which these knowledge gaps may be eliminated. Nutrient removal in CWs varies with the type of CW, vegetation, climate, season, geographical region, and management practices. Horizontal flow CWs tend to have good nitrate (NO3-) removal, as they provide good conditions for denitrification, but cannot remove ammonium (NH4+) due to limited ability to nitrify NH4+. Vertical flow CWs have good NH4+ removal, but their denitrification ability is low. Surface flow CWs decrease nitrous oxide (N2O) emissions but increase methane (CH4) emissions; subsurface flow CWs increase N2O and carbon dioxide (CO2) emissions, but decrease CH4 emissions. Mixed species of vegetation perform better than monocultures in increasing C and N removal and decreasing greenhouse gas (GHG) emissions, but empirical evidence is still scarce. Lower hydraulic loadings with higher hydraulic retention times enhance nutrient removal, but more empirical evidence is required to determine an optimum design. A conceptual model highlighting the current state of knowledge is presented and experimental work that should be undertaken to address knowledge gaps across CWs, vegetation and wastewater types, hydraulic loading rates and regimes, and retention times, is suggested. We recommend that further research on process-based C and N removal and on the balancing of end products into reactive and benign forms is critical to the assessment of the environmental performance of CWs.

A network model shows the importance of coupled processes in the microbial N cycle in the Cape Fear River Estuary

NASA Astrophysics Data System (ADS)

Hines, David E.; Lisa, Jessica A.; Song, Bongkeun; Tobias, Craig R.; Borrett, Stuart R.

2012-06-01

Estuaries serve important ecological and economic functions including habitat provision and the removal of nutrients. Eutrophication can overwhelm the nutrient removal capacity of estuaries and poses a widely recognized threat to the health and function of these ecosystems. Denitrification and anaerobic ammonium oxidation (anammox) are microbial processes responsible for the removal of fixed nitrogen and diminish the effects of eutrophication. Both of these microbial removal processes can be influenced by direct inputs of dissolved inorganic nitrogen substrates or supported by microbial interactions with other nitrogen transforming pathways such as nitrification and dissimilatory nitrate reduction to ammonium (DNRA). The coupling of nitrogen removal pathways to other transformation pathways facilitates the removal of some forms of inorganic nitrogen; however, differentiating between direct and coupled nitrogen removal is difficult. Network modeling provides a tool to examine interactions among microbial nitrogen cycling processes and to determine the within-system history of nitrogen involved in denitrification and anammox. To examine the coupling of nitrogen cycling processes, we built a nitrogen budget mass balance network model in two adjacent 1 cm3 sections of bottom water and sediment in the oligohaline portion of the Cape Fear River Estuary, NC, USA. Pathway, flow, and environ ecological network analyses were conducted to characterize the organization of nitrogen flow in the estuary and to estimate the coupling of nitrification to denitrification and of nitrification and DNRA to anammox. Centrality analysis indicated NH4+ is the most important form of nitrogen involved in removal processes. The model analysis further suggested that direct denitrification and coupled nitrification-denitrification had similar contributions to nitrogen removal while direct anammox was dominant to coupled forms of anammox. Finally, results also indicated that partial nitrification-anammox may play an important role in anammox nitrogen removal in the Cape Fear River Estuary.

Comparison of Habitat-Specific Nutrient Removal and Release in Pacific NW Salt Marshes at Multiple Spatial Scales - CERF

EPA Science Inventory

Wetlands can be sources, sinks and transformers of nutrients, although it is their role in nutrient removal that is valued as a water purification ecosystem service. In order to quantify that service for any wetland, it is important to understand the drivers of nutrient removal w...

What to do after nutrient removal?

PubMed

van der Graaf, J H

2001-01-01

In the Netherlands, interest in advanced treatment is increasing now that almost all wastewater treatment plants apply full biological treatment and nutrient removal. The resulting effluents have an excellent quality which can be improved further by applying advanced treatment processes like flocculating filtration, membrane filtration, UV or activated carbon, and others. The treated effluent can be re-used for various purposes, as process water, household water, urban water, for groundwater suppletion and drinking water. Nowadays many applications are investigated. In order to confirm the applicability pilot test investigations are done at various WWTPs. The results are promising; the cost estimations show increasing prospects. This will finally lead to the maturity of the advanced treatment. It will certainly contribute to a more sustainable water cycle.

Primary Productivity Regime and Nutrient Removal in the Danube Estuary

NASA Astrophysics Data System (ADS)

Humborg, C.

1997-11-01

The primary productivity regime, as well as the distribution of dissolved inorganic nutrients and particulate organic matter in the Danube estuary, were investigated during several cruises at different discharge regimes of the Danube River. The shallowness of the upper surface layer due to insignificant tidal mixing and strong stratification of the Danube estuary, as well as the high nutrient concentrations, are favourable for elevated primary production. The incident light levels at the bottom of the upper surface layer of the water column (0·5-3·0 m) were generally higher than 20% of the surface irradiance. Elevated chlorophyll (Chl) aconcentrations with maxima at mid salinities were found during each survey. Within the upper mixed layer estimated primary production of 0·2-4·4 g m-2day-1is very high compared with estuaries of other major world rivers. Mixing diagrams of dissolved inorganic nutrients reveal removal of significant quantities of nutrients during estuarine mixing. These observations were consistent with the distribution of particular organic matter, which was negatively correlated to the nutrient distribution during each survey. C:Chl aratios, as well as the elevated estimated production, indicate that biological transformation processes govern the nutrient distribution in this estuary.

Overall effect of carbon production and nutrient release in sludge holding tank on mainstream biological nutrient removal efficiency.

PubMed

Jabari, Pouria; Yuan, Qiuyan; Oleszkiewicz, Jan A

2017-09-11

The potential of hydrolysis/fermentation of activated sludge in sludge holding tank (SHT) to produce additional carbon for the biological nutrient removal (BNR) process was investigated. The study was conducted in anaerobic batch tests using the BNR sludge (from a full-scale Westside process) and the mixture of BNR sludge with conventional non-BNR activated sludge (to have higher biodegradable particulate chemical oxygen demand (bpCOD) in sludge). The BioWin 4.1 was used to simulate the anaerobic batch test of the BNR sludge. Also, the overall effect of FCOD production and nutrient release on BNR efficiency of the Westside process was estimated. The experimental results showed that the phosphorous uptake of sludge increased during hydrolysis/ fermentation condition up to the point when poly-P was completely utilized; afterwards, it decreased significantly. The BioWin simulation could not predict the loss of aerobic phosphorous uptake after poly-P was depleted. The results showed that in the case of activated sludge with relatively higher bpCOD (originating from plants with short sludge retention time or without primary sedimentation), beneficial effect of SHT on BNR performance is feasible. In order to increase the potential of SHT to enhance BNR efficiency, a relatively low retention time and high sludge load is recommended.

Municipal wastewater biological nutrient removal driven by the fermentation liquid of dairy wastewater.

PubMed

Liu, Hui; Chen, Yinguang; Wu, Jiang

2017-11-01

Carbon substrate is required by biological nutrient removal (BNR) microorganism, but it is usually insufficient in the influent of many municipal wastewater treatment plants. In this study the use of ethanol-enriched fermentation liquid, which was derived from dairy wastewater, as the preferred carbon substrate of BNR was reported. First, the application of dairy wastewater and food processing wastewater and their fermentation liquid as the carbon substrate of BNR was compared in the short-term tests. The fermented wastewater showed higher BNR performance than the unfermented one, and the fermentation liquid of dairy wastewater (FL-DW), which was obtained under pH 8 and fermentation time of 6 day, exhibited the highest phosphorus (95.5%) and total nitrogen (97.6%) removal efficiencies due to its high ethanol content (57.9%). Then, the long-term performance of FL-DW acting as the carbon substrate of BNR was compared with that of acetate and ethanol, and the FL-DW showed the greatest phosphorus and total nitrogen removal. Further investigation showed that the use of FL-DW caused the highest polyhydroxyalkanoates (PHAs) synthesis in BNR microbial cells, and more PHAs were used for phosphorus uptake and denitrification rather than glycogen synthesis and microbial growth. The FL-DW can be used as a preferred carbon substrate for BNR microbes. AB: aerobic end sludge active biomass; BNR: biological nutrient removal; DW: dairy wastewater; FL-DW: fermentation liquid of dairy wastewater; FPW: food processing wastewater; FL-FPW: fermentation liquid of food processing wastewater; PHAs: polyhydroxyalkanoates; PHB: poly-3-hydroxybutyrate; PHV: poly-3-hydroxyvalerate; PH2MV: poly-3-hydroxy-2- methylvalerate; PAOs: phosphorus accumulating organisms; SBR: sequencing batch reactor; SOP: soluble ortho-phosphorus; TN: total nitrogen; TSS: total suspended solids; VSS: volatile suspended solids; VFAs: volatile fatty acids; WWTPs: wastewater treatment plants.

Anaerobic on-site treatment of black water and dairy parlour wastewater in UASB-septic tanks at low temperatures.

PubMed

Luostarinen, Sari A; Rintala, Jukka A

2005-01-01

Anaerobic on-site treatment of synthetic black water (BW) and dairy parlour wastewater (DPWW) was studied in two-phased upflow anaerobic sludge blanket (UASB)-septic tanks at low temperatures (10-20 degrees C). At all temperatures, total chemical oxygen demand (COD(t)) removal was above 90% with BW and above 80% with DPWW and removal of total suspended solids (TSS) above 90% with both wastewaters. Moreover, dissolved COD (COD(dis)) removal was approx. 70% with both wastewaters indicating good biological activity of the sludges. With BW, a single-phased reactor was found sufficient for good COD removals, while with DPWW, a two-phased process was required. Temperature optimum of reactor sludges was still 35 degrees C after long (398d) operation. Most of the nutrients from BW were removed with TSS, while with DPWW nutrient removal was low. In conclusion, UASB-septic tank was found feasible for (pre)treatment of BW and DPWW at low temperatures.

Generation 3 treatment technology for diluted swine wastewater using high-rate solid-liquid separation and nutrient removal processes

USDA-ARS?s Scientific Manuscript database

The primary objective for this project was to construct and evaluate a third generation, innovative swine manure treatment system. The system was designed to: separate solids and liquids with the aid of settling and polymer flocculants; biologically remove ammonia nitrogen with bacteria adapted to h...

Biological permeable reactive barriers coupled with electrokinetic soil flushing for the treatment of diesel-polluted clay soil.

PubMed

Mena, Esperanza; Ruiz, Clara; Villaseñor, José; Rodrigo, Manuel A; Cañizares, Pablo

2015-01-01

Removal of diesel from spiked kaolin has been studied in the laboratory using coupled electrokinetic soil flushing (EKSF) and bioremediation through an innovative biological permeable reactive barriers (Bio-PRBs) positioned between electrode wells. The results show that this technology is efficient in the removal of pollutants and allows the soil to maintain the appropriate conditions for microorganism growth in terms of pH, temperature, and nutrients. At the same time, EKSF was demonstrated to be a very interesting technology for transporting pollutants, microorganisms and nutrients, although results indicate that careful management is necessary to avoid the depletion of nutrients, which are effectively transported by electro-migration. After two weeks of operation, 30% of pollutants are removed and energy consumption is under 70 kWh m(-3). Main fluxes (electroosmosis and evaporation) and changes in the most relevant parameters (nutrients, diesel, microorganisms, surfactants, moisture conductivity and pH) during treatment and in a complete post-study analysis are studied to give a comprehensive description of the most relevant processes occurring in the soil (pollutant transport and biodegradation). Copyright © 2014 Elsevier B.V. All rights reserved.

Macrophytes may not contribute significantly to removal of nutrients, pharmaceuticals, and antibiotic resistance in model surface constructed wetlands.

PubMed

Cardinal, Pascal; Anderson, Julie C; Carlson, Jules C; Low, Jennifer E; Challis, Jonathan K; Beattie, Sarah A; Bartel, Caitlin N; Elliott, Ashley D; Montero, Oscar F; Lokesh, Sheetal; Favreau, Alex; Kozlova, Tatiana A; Knapp, Charles W; Hanson, Mark L; Wong, Charles S

2014-06-01

Outdoor shallow wetland mesocosms, designed to simulate surface constructed wetlands to improve lagoon wastewater treatment, were used to assess the role of macrophytes in the dissipation of wastewater nutrients, selected pharmaceuticals, and antibiotic resistance genes (ARGs). Specifically, mesocosms were established with or without populations of Typha spp. (cattails), Myriophyllum sibiricum (northern water milfoil), and Utricularia vulgaris (bladderwort). Following macrophyte establishment, mesocosms were seeded with ARG-bearing organisms from a local wastewater lagoon, and treated with a single pulse of artificial municipal wastewater with or without carbamazepine, clofibric acid, fluoxetine, and naproxen (each at 7.6μg/L), as well as sulfamethoxazole and sulfapyridine (each at 150μg/L). Rates of pharmaceutical dissipation over 28d ranged from 0.073 to 3.0d(-1), corresponding to half-lives of 0.23 to 9.4d. Based on calculated rate constants, observed dissipation rates were consistent with photodegradation driving clofibric acid, naproxen, sulfamethoxazole, and sulfapyridine removal, and with sorption also contributing to carbamazepine and fluoxetine loss. Of the seven gene determinants assayed, only two genes for both beta-lactam resistance (blaCTX and blaTEM) and sulfonamide resistance (sulI and sulII) were found in sufficient quantity for monitoring. Genes disappeared relatively rapidly from the water column, with half-lives ranging from 2.1 to 99d. In contrast, detected gene levels did not change in the sediment, with the exception of sulI, which increased after 28d in pharmaceutical-treated systems. These shallow wetland mesocosms were able to dissipate wastewater contaminants rapidly. However, no significant enhancement in removal of nutrients or pharmaceuticals was observed in mesocosms with extensive aquatic plant communities. This was likely due to three factors: first, use of naïve systems with an unchallenged capacity for nutrient assimilation and contaminant removal; second, nutrient sequestration by ubiquitous filamentous algae; and third, dominance of photolytic processes in the removal of pharmaceuticals, which overshadowed putative plant-related processes. Copyright © 2014 Elsevier B.V. All rights reserved.

Nutrient Removal in Wastewater Treatment

ERIC Educational Resources Information Center

Shah, Kanti L.

1973-01-01

Discusses the sources and effects of nutrients in wastewater, and the methods of their removal in wastewater treatment. In order to conserve water resources and eliminate the cost of nutrient removal, treated effluent should be used wherever possible for irrigation, since it contains all the ingredients for proper plant growth. (JR)

On-line removal of volatile fatty acids from CELSS anaerobic bioreactor via nanofiltration

NASA Technical Reports Server (NTRS)

Colon, Guillermo

1995-01-01

The CELSS (controlled ecological life support system) resource recovery system, which is a waste processing system, uses aerobic and anaerobic bioreactors to recover plants nutrients and secondary foods from the inedible biomass. The anaerobic degradation of the inedible biomass by means of culture of rumen bacteria,generates organic compounds such as volatile fatty acids (acetic, propionic, butyric, VFA) and ammonia. The presence of VFA in the bioreactor medium at fairly low concentrations decreases the microbial population's metabolic reactions due to end-product inhibition. Technologies to remove VFA continuously from the bioreactor are of high interest. Several candidate technologies were analyzed, such as organic solvent liquid-liquid extraction, adsorption and/or ion exchange, dialysis, electrodialysis, and pressure driven membrane separation processes. The proposed technique for the on-line removal of VFA from the anaerobic bioreactor was a nanofiltration membrane recycle bioreactor. In order to establish the nanofiltration process performance variables before coupling it to the bioreactor, a series of experiments were carried out using a 10,000 MWCO tubular ceramic membrane module. The variables studied were the bioreactor slurry permeation characteristics, such as, the permeate flux, VFA and the nutrient removal rates as a function of applied transmembrane pressure, fluid recirculation velocity, suspended matter concentration, and process operating time. Results indicate that the permeate flux, VFA and nutrients removal rates are directly proportional to the fluid recirculation velocity in the range between 0.6 to 1.0 m/s, applied pressure when these are low than 1.5 bar, and inversely proportional to the total suspended solids concentration in the range between 23,466 to 34,880. At applied pressure higher than 1.5 bar the flux is not more linearly dependent due to concentration polarization and fouling effects over the membrange surface. It was also found that the permeate flux declines rapidly during the first 5 to 8 hours, and then levels off with a diminishing rate of flux decay.

Relative importance of P and N in macrophyte and epilithic algae biomass in a wastewater-impacted oligotrophic river.

PubMed

Taube, Nadine; He, Jianxun; Ryan, M Cathryn; Valeo, Caterina

2016-08-01

The role of nutrient loading on biomass growth in wastewater-impacted rivers is important in order to effectively optimize wastewater treatment to avoid excessive biomass growth in the receiving water body. This paper directly relates wastewater treatment plant (WWTP) effluent nutrients (including ammonia (NH3-N), nitrate (NO3-N) and total phosphorus (TP)) to the temporal and spatial distribution of epilithic algae and macrophyte biomass in an oligotrophic river. Annual macrophyte biomass, epilithic algae data and WWTP effluent nutrient data from 1980 to 2012 were statistically analysed. Because discharge can affect aquatic biomass growth, locally weighted scatterplot smoothing (LOWESS) was used to remove the influence of river discharge from the aquatic biomass (macrophytes and algae) data before further analysis was conducted. The results from LOWESS indicated that aquatic biomass did not increase beyond site-specific threshold discharge values in the river. The LOWESS-estimated biomass residuals showed a variable response to different nutrients. Macrophyte biomass residuals showed a decreasing trend concurrent with enhanced nutrient removal at the WWTP and decreased effluent P loading, whereas epilithic algae biomass residuals showed greater response to enhanced N removal. Correlation analysis between effluent nutrient concentrations and the biomass residuals (both epilithic algae and macrophytes) suggested that aquatic biomass is nitrogen limited, especially by NH3-N, at most sampling sites. The response of aquatic biomass residuals to effluent nutrient concentrations did not change with increasing distance to the WWTP but was different for P and N, allowing for additional conclusions about nutrient limitation in specific river reaches. The data further showed that the mixing process between the effluent and the river has an influence on the spatial distribution of biomass growth.

System dynamics modeling of nitrogen removal in a stormwater infiltration basin with biosorption-activated media.

PubMed

Xuan, Zhemin; Chang, Ni-Bin; Wanielista, Martin P; Williams, Evan Shane

2013-07-01

Stormwater infiltration basins, one of the typical stormwater best management practices, are commonly constructed for surface water pollution control, flood mitigation, and groundwater restoration in rural or residential areas. These basins have soils with better infiltration capacity than the native soil; however, the ever-increasing contribution of nutrients to groundwater from stormwater due to urban expansion makes existing infiltration basins unable to meet groundwater quality criteria related to environmental sustainability and public health. This issue requires retrofitting current infiltration basins for flood control as well as nutrient control before the stormwater enters the groundwater. An existing stormwater infiltration basin in north-central Florida was selected, retrofitted, and monitored to identify subsurface physiochemical and biological processes during 2007-2010 to investigate nutrient control processes. This implementation in the nexus of contaminant hydrology and ecological engineering adopted amended soil layers packed with biosorption activated media (BAM; tire crumb, silt, clay, and sand) to perform nutrient removal in a partitioned forebay using a berm. This study presents an infiltration basin-nitrogen removal (IBNR) model, a system dynamics model that simulates nitrogen cycling in this BAM-based stormwater infiltration basin with respect to changing hydrologic conditions and varying dissolved nitrogen concentrations. Modeling outputs of IBNR indicate that denitrification is the biogeochemical indicator in the BAM layer that accounted for a loss of about one third of the total dissolved nitrogen mass input. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effect of plants in constructed wetlands for organic carbon and nutrient removal: a review of experimental factors contributing to higher impact and suggestions for future guidelines.

PubMed

Jesus, João M; Danko, Anthony S; Fiúza, António; Borges, Maria-Teresa

2018-02-01

Constructed wetland is a proven technology for water pollution removal, but process mechanisms and their respective contribution are not fully understood. The present review details the effect of plants on removal efficiency of constructed wetlands by focusing on literature that includes experiments with unplanted controls for organic carbon and nutrient (N and P) removal. The contribution of plant direct uptake is also assessed. Although it was found that several studies, mostly at laboratory or pilot scales, showed no statistical differences between planted and unplanted controls, some factors were found that help maximize the effect of plants. This study intends to contribute to a better understanding of the significance of the effect of plants in a constructed wetland, as well as to suggest a set of experimental guidelines in this field.

Muscle Contraction and Force: the Importance of an Ancillary Network, Nutrient Supply and Waste Removal

PubMed Central

Brüggemann, Dagmar A.; Risbo, Jens; Pierzynowski, Stefan G.; Harrison, Adrian P.

2008-01-01

Muscle contraction studies often focus solely on myofibres and the proteins known to be involved in the processes of sarcomere shortening and cross-bridge cycling, but skeletal muscle also comprises a very elaborate ancillary network of capillaries, which not only play a vital role in terms of nutrient delivery and waste product removal, but are also tethered to surrounding fibres by collagen ”wires”. This paper therefore addresses aspects of the ancillary network of skeletal muscle at both a microscopic and functional level in order to better understand its role holistically as a considerable contributor to force transfer within muscular tissue. PMID:19325816

Complete nutrient recovery from source-separated urine by nitrification and distillation.

PubMed

Udert, K M; Wächter, M

2012-02-01

In this study we present a method to recover all nutrients from source-separated urine in a dry solid by combining biological nitrification with distillation. In a first process step, a membrane-aerated biofilm reactor was operated stably for more than 12 months, producing a nutrient solution with a pH between 6.2 and 7.0 (depending on the pH set-point), and an ammonium to nitrate ratio between 0.87 and 1.15 gN gN(-1). The maximum nitrification rate was 1.8 ± 0.3 gN m(-2) d(-1). Process stability was achieved by controlling the pH via the influent. In the second process step, real nitrified urine and synthetic solutions were concentrated in lab-scale distillation reactors. All nutrients were recovered in a dry powder except for some ammonia (less than 3% of total nitrogen). We estimate that the primary energy demand for a simple nitrification/distillation process is four to five times higher than removing nitrogen and phosphorus in a conventional wastewater treatment plant and producing the equivalent amount of phosphorus and nitrogen fertilizers. However, the primary energy demand can be reduced to values very close to conventional treatment, if 80% of the water is removed with reverse osmosis and distillation is operated with vapor compression. The ammonium nitrate content of the solid residue is below the limit at which stringent EU safety regulations for fertilizers come into effect; nevertheless, we propose some additional process steps that will increase the thermal stability of the solid product. Copyright © 2011 Elsevier Ltd. All rights reserved.

Assessment of full-scale biological nutrient removal systems upgraded with physico-chemical processes for the removal of emerging pollutants present in wastewaters from Mexico.

PubMed

Estrada-Arriaga, Edson Baltazar; Cortés-Muñoz, Juana Enriqueta; González-Herrera, Arturo; Calderón-Mólgora, César Guillermo; de Lourdes Rivera-Huerta, Ma; Ramírez-Camperos, Esperanza; Montellano-Palacios, Leticia; Gelover-Santiago, Silvia Lucila; Pérez-Castrejón, Sara; Cardoso-Vigueros, Lina; Martín-Domínguez, Alejandra; García-Sánchez, Liliana

2016-11-15

Two full-scale biological nutrient removal systems upgraded with three physico-chemical processes (coagulation, chemical precipitation, and neutral Fenton) were evaluated in order to determine the removal of emerging pollutants (EPs) present in municipal wastewater from Mexico. Between 41 and 55 EPs were detected in the influents of two wastewater treatment plants (WWTPs), including personal care products (PPCPs), antibiotics, analgesics, antiepileptics, antilipidemics, antihypertensives, antiseptics, stimulants, and hormones. Emerging pollutants were detected at concentrations ranging from 0.69ng/L to 94,600ng/L. High concentrations of emerging pollutants were found during dry season. WWTP 1, integrated by oxidation ditches and UV light lamps, showed removal efficiencies of EPs between 20% and 22%. On the other hand, WWTP 2 consisted of anaerobic/anoxic/aerobic tanks coupled with two disinfection processes; chlorine dioxide and UV light lamps, for which the removal of EPs was significant (up to 80%). The concentrations of emerging pollutants in WWTP 1 effluent was found within a range

Biological nutrients removal from the supernatant originating from the anaerobic digestion of the organic fraction of municipal solid waste.

PubMed

Malamis, S; Katsou, E; Di Fabio, S; Bolzonella, D; Fatone, F

2014-09-01

This study critically evaluates the biological processes and techniques applied to remove nitrogen and phosphorus from the anaerobic supernatant produced from the treatment of the organic fraction of municipal solid waste (OFMSW) and from its co-digestion with other biodegradable organic waste (BOW) streams. The wide application of anaerobic digestion for the treatment of several organic waste streams results in the production of high quantities of anaerobic effluents. Such effluents are characterized by high nutrient content, because organic and particulate nitrogen and phosphorus are hydrolyzed in the anaerobic digestion process. Consequently, adequate post-treatment is required in order to comply with the existing land application and discharge legislation in the European Union countries. This may include physicochemical and biological processes, with the latter being more advantageous due to their lower cost. Nitrogen removal is accomplished through the conventional nitrification/denitrification, nitritation/denitritation and the complete autotrophic nitrogen removal process; the latter is accomplished by nitritation coupled with the anoxic ammonium oxidation process. As anaerobic digestion effluents are characterized by low COD/TKN ratio, conventional denitrification/nitrification is not an attractive option; short-cut nitrogen removal processes are more promising. Both suspended and attached growth processes have been employed to treat the anaerobic supernatant. Specifically, the sequencing batch reactor, the membrane bioreactor, the conventional activated sludge and the moving bed biofilm reactor processes have been investigated. Physicochemical phosphorus removal via struvite precipitation has been extensively examined. Enhanced biological phosphorus removal from the anaerobic supernatant can take place through the sequencing anaerobic/aerobic process. More recently, denitrifying phosphorus removal via nitrite or nitrate has been explored. The removal of phosphorus from the anaerobic supernatant of OFMSW is an interesting research topic that has not yet been explored. At the moment, standardization in the design of facilities that treat anaerobic supernatant produced from the treatment of OFMSW is still under development. To move toward this direction, it is first necessary to assess the performance of alternative treatment options. It study concentrates existing data regarding the characteristics of the anaerobic supernatant produced from the treatment of OFMSW and from their co-digestion with other BOW. This provides data documenting the effect of the anaerobic digestion operating conditions on the supernatant quality and critically evaluates alternative options for the post-treatment of the liquid fraction produced from the anaerobic digestion process.

Modeling nutrient retention at the watershed scale: Does small stream research apply to the whole river network?

NASA Astrophysics Data System (ADS)

Aguilera, Rosana; Marcé, Rafael; Sabater, Sergi

2013-06-01

are conveyed from terrestrial and upstream sources through drainage networks. Streams and rivers contribute to regulate the material exported downstream by means of transformation, storage, and removal of nutrients. It has been recently suggested that the efficiency of process rates relative to available nutrient concentration in streams eventually declines, following an efficiency loss (EL) dynamics. However, most of these predictions are based at the reach scale in pristine streams, failing to describe the role of entire river networks. Models provide the means to study nutrient cycling from the stream network perspective via upscaling to the watershed the key mechanisms occurring at the reach scale. We applied a hybrid process-based and statistical model (SPARROW, Spatially Referenced Regression on Watershed Attributes) as a heuristic approach to describe in-stream nutrient processes in a highly impaired, high stream order watershed (the Llobregat River Basin, NE Spain). The in-stream decay specifications of the model were modified to include a partial saturation effect in uptake efficiency (expressed as a power law) and better capture biological nutrient retention in river systems under high anthropogenic stress. The stream decay coefficients were statistically significant in both nitrate and phosphate models, indicating the potential role of in-stream processing in limiting nutrient export. However, the EL concept did not reliably describe the patterns of nutrient uptake efficiency for the concentration gradient and streamflow values found in the Llobregat River basin, posing in doubt its complete applicability to explain nutrient retention processes in stream networks comprising highly impaired rivers.

Post-anoxic denitrification via nitrite driven by PHB in feast-famine sequencing batch reactor.

PubMed

Chen, Hong-Bo; Yang, Qi; Li, Xiao-Ming; Wang, Yan; Luo, Kun; Zeng, Guang-Ming

2013-08-01

Recently, it was found that excess phosphorus removal could be induced by aerobic/extended-idle regime. In this study, an anoxic period was introduced after the aeration to realize simultaneous nitrogen and phosphorus removal. The results demonstrated that stable partial nitrification could be achieved by controlling the aeration duration at 2.5h because it could not only obtain a desirable ammonia oxidation to nitrite but also avoid the extensive aeration converting nitrite to nitrate, and moreover, the accumulated poly-3-hydroxybutyrate still remain in a relative sufficient concentration (1.5mmolCg(-1) VSS), which could subsequently served as internal carbon source for post-anoxic denitrification. The nitrite accumulation ratio was observed to have relatively high correlation with biological nutrient removal. Over stages with stable high-level nitrite accumulation, the process achieved desirable and stable nitrogen and phosphorus removal efficiencies averaging 95% and 99% respectively. Fluorescence in situ hybridization analysis showed that the faster growth rate of the ammonia oxidizing bacteria than the nitrite oxidizing bacteria was the main reason for achieving nitrite accumulation. In addition, the secondary phosphorus release was negligible and the process maintained excellent nutrient removal under low influent ammonia nitrogen. Copyright © 2013 Elsevier Ltd. All rights reserved.

Approaches to characterizing biogeochemistry effects of groundwater and surface water interaction at the riparian interface

EPA Science Inventory

Groundwater-surface water interaction (GSI) in riparian ecosystems strongly influences biological activity that controls nutrient flux and processes. Shallow groundwater in riparian zones is a hot spot for nitrogen removal processes, a storage zone for solutes, and a target for ...

Nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.

PubMed

Song, Yong-Hui; Qiu, Guang-Lei; Yuan, Peng; Cui, Xiao-Yu; Peng, Jian-Feng; Zeng, Ping; Duan, Liang; Xiang, Lian-Cheng; Qian, Feng

2011-06-15

Anaerobically digested swine wastewater contains high concentrations of phosphorus (P) and nitrogen (N). A pilot-scale experiment was carried out for nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization. In the pilot plant, a sequencing batch reactor (SBR) and a continuous-flow reactor with struvite accumulation devices were designed and employed. The wastewater pH value was increased by CO(2) stripping, and the struvite crystallization process was performed without alkali and Mg(2+) additions. Results of the long-term operation of the system showed that, both reactors provided up to 85% P removal and recovery over wide ranges of aeration times (1.0-4.0 h), hydraulic retention times (HRT) (6.0-15.0 h) and temperatures (0-29.5°C) for an extended period of 247 d, in which approximate 30% of P was recovered by the struvite accumulation devices. However, 40-90% of NH(4)(+)-N removed was through air stripping instead of being immobilized in the recovered solids. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite with purity of more than 90%. This work demonstrated the feasibility and effects of nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions. Copyright © 2011 Elsevier B.V. All rights reserved.

Novel Self-driven Microbial Nutrient Recovery Cell with Simultaneous Wastewater Purification

PubMed Central

Chen, Xi; Sun, Dongya; Zhang, Xiaoyuan; Liang, Peng; Huang, Xia

2015-01-01

Conventional wastewater purification technologies consume large amounts of energy, while the abundant chemical energy and nutrient resources contained in sewage are wasted in such treatment processes. A microbial nutrient recovery cell (MNRC) has been developed to take advantage of the energy contained in wastewater, in order to simultaneously purify wastewater and recover nutrient ions. When wastewater was circulated between the anode and cathode chambers of the MNRC, the organics (COD) were removed by bacteria while ammonium and phosphate (NH4+-N and PO43−-P) were recovered by the electrical field that was produced using in situ energy in the wastewater without additional energy input. The removal efficiencies from wastewater were >82% for COD, >96% for NH4+-N, and >64% for PO43−-P in all the operational cycles. Simultaneously, the concentrations of NH4+ and PO43− in the recovery chamber increased to more than 1.5 and 2.2 times, respectively, compared with the initial concentrations in wastewater. The MNRC provides proof-of-concept as a sustainable, self-driven approach to efficient wastewater purification and nutrient recovery in a comprehensive bioelectrochemical system. PMID:26503712

Potential of diatom consortium developed by nutrient enrichment for biodiesel production and simultaneous nutrient removal from waste water.

PubMed

Marella, Thomas Kiran; Parine, Narasimha Reddy; Tiwari, Archana

2018-05-01

Because of the decreasing fossil fuel supply and increasing greenhouse gas (GHG) emissions, microalgae have been identified as a viable and sustainable feedstock for biofuel production. The major effect of the release of wastewater rich in organic compounds has led to the eutrophication of freshwater ecosystems. A combined approach of freshwater diatom cultivation with urban sewage water treatment is a promising solution for nutrient removal and biofuel production. In this study, urban wastewater from eutrophic Hussain Sagar Lake was used to cultivate a diatom algae consortium, and the effects of silica and trace metal enrichment on growth, nutrient removal, and lipid production were evaluated. The nano-silica-based micronutrient mixture Nualgi containing Si, Fe, and metal ions was used to optimize diatom growth. Respectively, N and P reductions of 95.1% and 88.9%, COD and BOD reductions of 91% and 51% with a biomass yield of 122.5 mg L -1  day -1 and lipid productivity of 37 mg L -1  day -1 were observed for cultures grown in waste water using Nualgi. Fatty acid profiles revealed 13 different fatty acids with slight differences in their percentage of dry cell weight (DCW) depending on enrichment level. These results demonstrate the potential of diatom algae grown in wastewater to produce feedstock for renewable biodiesel production. Enhanced carbon and excess nutrient utilization makes diatoms ideal candidates for co-processes such as CO 2 sequestration, biodiesel production, and wastewater phycoremediation.

Contribution of Wastewater Treatment Plant Effluents to Nutrient Dynamics in Aquatic Systems: A Review

NASA Astrophysics Data System (ADS)

Carey, Richard O.; Migliaccio, Kati W.

2009-08-01

Excessive nutrient loading (considering nitrogen and phosphorus) is a major ongoing threat to water quality and here we review the impact of nutrient discharges from wastewater treatment plants (WWTPs) to United States (U.S.) freshwater systems. While urban and agricultural land uses are significant nonpoint nutrient contributors, effluent from point sources such as WWTPs can overwhelm receiving waters, effectively dominating hydrological characteristics and regulating instream nutrient processes. Population growth, increased wastewater volumes, and sustainability of critical water resources have all been key factors influencing the extent of wastewater treatment. Reducing nutrient concentrations in wastewater is an important aspect of water quality management because excessive nutrient concentrations often prevent water bodies from meeting designated uses. WWTPs employ numerous physical, chemical, and biological methods to improve effluent water quality but nutrient removal requires advanced treatment and infrastructure that may be economically prohibitive. Therefore, effluent nutrient concentrations vary depending on the particular processes used to treat influent wastewater. Increasingly stringent regulations regarding nutrient concentrations in discharged effluent, along with greater freshwater demand in populous areas, have led to the development of extensive water recycling programs within many U.S. regions. Reuse programs provide an opportunity to reduce or eliminate direct nutrient discharges to receiving waters while allowing for the beneficial use of reclaimed water. However, nutrients in reclaimed water can still be a concern for reuse applications, such as agricultural and landscape irrigation.

Nutrients removal and substrate enzyme activities in vertical subsurface flow constructed wetlands for mariculture wastewater treatment: Effects of ammonia nitrogen loading rates and salinity levels.

PubMed

Li, Meng; Liang, Zhenlin; Callier, Myriam D; Roque d'orbcastel, Emmanuelle; Sun, Guoxiang; Ma, Xiaona; Li, Xian; Wang, Shunkui; Liu, Ying; Song, Xiefa

2018-06-01

This study aims to investigate the effects of ammonia nitrogen loading rates and salinity levels on nutrients removal rates and substrate enzyme activities of constructed wetland (CW) microcosms planted with Salicornia bigelovii treating mariculture wastewater. Activities of urease (UA), dehydrogenase (DA), protease (PrA) and phosphatase (PA) were considered. Using principal component analysis (PCA), nutrient removal index (NRI) and enzyme activity index (EAI) were developed to evaluate the effects. The results revealed that increasing ammonia nitrogen loading rates had positive effects on nitrogen removal rates (i.e. NH 4 -N and DIN) and enhanced substrate enzyme activities. Compared with low salinity (i.e. 15 and 22), high salinity levels (i.e. 29 and 36) enhanced nutrients removal rates, DA and UA, but weaken PA and PrA. In conclusion, CW microcosms with Salicornia bigelovii can be used for the removal of nutrients under a range of ammonia nitrogen loadings and high salinity levels. Copyright © 2018 Elsevier Ltd. All rights reserved.

Interacting Physical and Biological Processes Affecting Nutrient Transport Through Human Dominated Landscapes

NASA Astrophysics Data System (ADS)

Finlay, J. C.

2015-12-01

Human activities increasingly dominate biogeochemical cycles of limiting nutrients on Earth. Urban and agricultural landscapes represent the largest sources of excess nutrients that drive water quality degradation. The physical structure of both urban and agricultural watersheds has been extensively modified, and these changes have large impacts on water and nutrient transport. Despite strong physical controls over nutrient transport in human dominated landscapes, biological processes play important roles in determining the fates of both nitrogen and phosphorus. This talk uses examples from research in urban and agricultural watersheds in the Midwestern USA to illustrate interactions of physical and biological controls over nutrient cycles that have shifted nitrogen (N) and phosphorus (P) sources and cycling in unexpected ways in response to management changes. In urban watersheds, efforts to improve water quality have been hindered by legacy sources of phosphorus added to storm water through transport to drainage systems by vegetation. Similarly, reductions in field erosion in agricultural watersheds have not led to major reductions in phosphorus transport, because of continued release of biological sources of P. Where management of phosphorus has been most effective in reducing eutrophication of lakes, decreases in N removal processes have led to long term increases in N concentration and transport. Together, these examples show important roles for biological processes affecting nutrient movement in highly modified landscapes. Consideration of the downstream physical and biological responses of management changes are thus critical toward identification of actions that will most effectively reduce excess nutrients watersheds and coastal zones.

Supplementation of inorganic phosphate enhancing the removal efficiency of tannery sludge-borne Cr through bioleaching.

PubMed

Zheng, Guanyu; Zhou, Lixiang

2011-10-15

Four inorganic mineral nutrients including NH4+, K+, Mg2+ and soluble inorganic phosphate (Pi) were investigated to reveal the potential limiting nutrients for tannery sludge bioleaching process driven by Acidithiobacillus species, and the feasibility of supplementing the limiting nutrients to accelerate tannery sludge bioleaching was studied in the present study. It was found that the concentration of Pi was lower than 3.5 mg/L throughout the whole bioleaching process, which is the most probable restricting nutrient for tannery sludge bioleaching. Further experiments revealed that the deficiency of Pi could seriously influence the growth of Acidithiobacillus thiooxidans and lower its oxidization capacity for S0, and the limiting concentration of Pi for the growth of A. thiooxidans was 6 mg/L. The low concentration of soluble Pi in sludge matrix was resulted from the extremely strong sorbing/binding capacity of tannery sludge for phosphate. The supplementation of more than 1.6 g/L KH2PO4 into tannery sludge bioleaching system could effectively stimulate the growth of Acidithiobacillus species, enhance Cr removal rate and further shorten tannery sludge bioleaching period from 10 days to 7 days. Therefore, inorganic phosphate supplementation is an effective and feasible method to accelerate tannery sludge bioleaching process, and the optimum dosage of KH2PO4 was 1.6 g/L for tannery sludge with 5.1% of total solids. Copyright © 2011 Elsevier Ltd. All rights reserved.

Phytoremediation to remove nutrients and improve eutrophic stormwaters using water lettuce (Pistia stratiotes L.).

PubMed

Lu, Qin; He, Zhenli L; Graetz, Donald A; Stoffella, Peter J; Yang, Xiaoe

2010-01-01

Water quality impairment by nutrient enrichment from agricultural activities has been a concern worldwide. Phytoremediation technology using aquatic plants in constructed wetlands and stormwater detention ponds is increasingly applied to remediate eutrophic waters. The objectives of this study were to evaluate the effectiveness and potential of water lettuce (Pistia stratiotes L.) in removing nutrients including nitrogen (N) and phosphorus (P) from stormwater in the constructed water detention systems before it is discharged into the St. Lucie Estuary, an important surface water system in Florida, using phytoremediation technologies. In this study, water lettuce (P. stratiotes) was planted in the treatment plots of two stormwater detention ponds (East and West Ponds) in 2005-2007 and water samples from both treatment and control plots were weekly collected and analyzed for water quality properties including pH, electrical conductivity, turbidity, suspended solids, and nutrients (N and P). Optimum plant density was maintained and plant samples were collected monthly and analyzed for nutrient contents. Water quality in both ponds was improved, as evidenced by decreases in water turbidity, suspended solids, and nutrient concentrations. Water turbidity was decreased by more than 60%. Inorganic N (NH(4) (+) and NO(3) (-)) concentrations in treatment plots were more than 50% lower than those in control plots (without plant). Reductions in both PO(4) (3-) and total P were approximately 14-31%, as compared to the control plots. Water lettuce contained average N and P concentrations of 17 and 3.0 g kg(-1), respectively, and removed 190-329 kg N ha(-1) and 25-34 kg P ha(-1) annually. Many aquatic plants have been used to remove nutrients from eutrophic waters but water lettuce proved superior to most other plants in nutrient removal efficiency, owing to its rapid growth and high biomass yield potential. However, the growth and nutrient removal potential are affected by many factors such as temperature, water salinity, and physiological limitations of the plant. Low temperature, high concentration of salts, and low concentration of nutrients may reduce the performance of this plant in removing nutrients. The results from this study indicate that water lettuce has a great potential in removing N and P from eutrophic stormwaters and improving other water quality properties.

Nutrients removal and bacterial community structure for low C/N municipal wastewater using a modified anaerobic/anoxic/oxic (mA2/O) process in North China.

PubMed

Zhang, Shihua; Huang, Zhijia; Lu, Shujian; Zheng, Jun; Zhang, Xinxi

2017-11-01

A modified anaerobic/anoxic/oxic (mA2/O) process based on utilizing the internal carbon source and adding polypropylene carriers was operated for 90d to investigate the nutrients removal performance and bacterial community. This system exhibited a stable and efficient performance, particularly, in removing the NH 4 + -N and total phosphorus. The results of high-throughput sequencing showed that the 13 dominant genera containing Pseudomonas, Comamonas, Arcobacter, Nitrobacteria, Nitrosospira, Nitrosomonas, Bacteroides, Flavobacterium, Rhizobium, Acinetobacter, Zoogloea, Rhodocyclus and Moraxella were shared by five zones, inferring that they were the essential players in treating low C/N (below 5.0) municipal wastewater around 10°C. The average abundance of Nitrosospira (4.21%) was higher than that of Nitrosomonas (2.93%), suggested that Nitrosospira performed well under low temperature for nitrification. Additionally, both known Rhodocyclus-related PAOs and GAOs Competibacter were not detected possibly due to low temperature. Redundancy analysis (RDA) indicated that DO played more important roles in regulating bacterial community composition than HRT. Copyright © 2017 Elsevier Ltd. All rights reserved.

Removal characteristics of pharmaceuticals and personal care products: Comparison between membrane bioreactor and various biological treatment processes.

PubMed

Park, Junwon; Yamashita, Naoyuki; Park, Chulhwi; Shimono, Tatsumi; Takeuchi, Daniel M; Tanaka, Hiroaki

2017-07-01

We investigated the concentrations of 57 target compounds in the different treatment units of various biological treatment processes in South Korea, including modified biological nutrient removal (BNR), anaerobic-anoxic-aerobic (A2O), and membrane bioreactor (MBR) systems, to elucidate the occurrence and removal fates of PPCPs in WWTPs. Biological treatment processes appeared to be most effective in eliminating most PPCPs, whereas some PPCPs were additionally removed by post-treatment. With the exception of the MBR process, the A2O system was effective for PPCPs removal. As a result, removal mechanisms were evaluated by calculating the mass balances in A2O and a lab-scale MBR process. The comparative study demonstrated that biodegradation was largely responsible for the improved removal performance found in lab-scale MBR (e.g., in removing bezafibrate, ketoprofen, and atenolol). Triclocarban, ciprofloxacin, levofloxacin and tetracycline were adsorbed in large amounts to MBR sludge. Increased biodegradability was also observed in lab-scale MBR, despite the highly adsorbable characteristics. The enhanced biodegradation potential seen in the MBR process thus likely plays a key role in eliminating highly adsorbable compounds as well as non-degradable or persistent PPCPs in other biological treatment processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nutrient bioassimilation capacity of aquacultured oysters: quantification of an ecosystem service.

PubMed

Higgins, Colleen B; Stephenson, Kurt; Brown, Bonnie L

2011-01-01

Like many coastal zones and estuaries, the Chesapeake Bay has been severely degraded by cultural eutrophication. Rising implementation costs and difficulty achieving nutrient reduction goals associated with point and nonpoint sources suggests that approaches supplemental to source reductions may prove useful in the future. Enhanced oyster aquaculture has been suggested as one potential policy initiative to help rid the Bay waters of excess nutrients via harvest of bioassimilated nutrients. To assess this potential, total nitrogen (TN), total phosphorous (TP), and total carbon (TC) content were measured in oyster tissue and shell at two floating-raft cultivation sites in the Chesapeake Bay. Models were developed based on the common market measurement of total length (TL) for aquacultured oysters, which was strongly correlated to the TN (R2 = 0.76), TP (R2 = 0.78), and TC (R2 = 0.76) content per oyster tissue and shell. These models provide resource managers with a tool to quantify net nutrient removal. Based on model estimates, 10(6) harvest-sized oysters (76 mm TL) remove 132 kg TN, 19 kg TP, and 3823 kg TC. In terms of nutrients removed per unit area, oyster harvest is an effective means of nutrient removal compared with other nonpoint source reduction strategies. At a density of 286 oysters m(-2), assuming no mortality, harvest size nutrient removal rates can be as high as 378 kg TN ha(-1), 54 kg TP ha(-1), and 10,934 kg TC ha(-1) for 76-mm oysters. Removing 1 t N from the Bay would require harvesting 7.7 million 76-mm TL cultivated oysters.

Carbon mass balance and microbial ecology in a laboratory scale reactor achieving simultaneous sludge reduction and nutrient removal.

PubMed

Huang, Pei; Li, Liang; Kotay, Shireen Meher; Goel, Ramesh

2014-04-15

Solids reduction in activated sludge processes (ASP) at source using process manipulation has been researched widely over the last two-decades. However, the absence of nutrient removal component, lack of understanding on the organic carbon, and limited information on key microbial community in solids minimizing ASP preclude the widespread acceptance of sludge minimizing processes. In this manuscript, we report simultaneous solids reduction through anaerobiosis along with nitrogen and phosphorus removals. The manuscript also reports carbon mass balance using stable isotope of carbon, microbial ecology of nitrifiers and polyphosphate accumulating organisms (PAOs). Two laboratory scale reactors were operated in anaerobic-aerobic-anoxic (A(2)O) mode. One reactor was run in the standard mode (hereafter called the control-SBR) simulating conventional A(2)O type of activated sludge process and the second reactor was run in the sludge minimizing mode (called the modified-SBR). Unlike other research efforts where the sludge minimizing reactor was maintained at nearly infinite solids retention time (SRT). To sustain the efficient nutrient removal, the modified-SBR in this research was operated at a very small solids yield rather than at infinite SRT. Both reactors showed consistent NH3-N, phosphorus and COD removals over a period of 263 days. Both reactors also showed active denitrification during the anoxic phase even if there was no organic carbon source available during this phase, suggesting the presence of denitrifying PAOs (DNPAOs). The observed solids yield in the modified-SBR was 60% less than the observed solids yield in the control-SBR. Specific oxygen uptake rate (SOUR) for the modified-SBR was almost 44% more than the control-SBR under identical feeding conditions, but was nearly the same for both reactors under fasting conditions. The modified-SBR showed greater diversity of ammonia oxidizing bacteria and PAOs compared to the control-SBR. The diversity of PAOs in the modified-SBR was even more interesting in which case novel clades of Candidatus Accumulibacter phosphatis (CAP), an uncultured but widely found PAOs, were found. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biogeochemical Hotspots: Small Geographically Isolated Wetlands and their Impacts at the Landscape Scale

NASA Astrophysics Data System (ADS)

Basu, N. B.

2017-12-01

Wetlands provide a wide variety of ecosystem services, including retention of sediment and nutrients, and subsequent improvements in downstream water quality. In fact, a recent review suggests that 64% of reactive nitrogen (N) retention in US freshwater systems occurs in wetlands, while 28% occurs in lakes and reservoirs, and only 8% occurs in streams and rivers. Although the processes controlling nutrient retention in wetlands are well known, there is a lack of quantitative understanding of the relative nutrient filtering abilities of wetlands of various sizes, and in various landscape positions. Our inability to recognize the value of wetlands has led to their dramatic loss in the last few decades. Specifically, there has been an increased loss of geographically isolated wetlands, small upland wetlands that receive fewer legal protections due to their apparent isolation from jurisdictional waters. In this study, we use a meta-analyses approach to quantify the role of small wetlands in landscape scale nutrient processing. We synthesized data from 600 lentic systems around the world to gain insight into the relationship between hydrologic and biogeochemical controls on nutrient retention. Our results indicate that the first-order reaction rate constant k(T-1), is inversely proportional to the residence time, across 6 orders of magnitude in residence time for total N, total P, nitrate, and phosphate. We used a sediment-water model to show how nutrient removal processes are impacted by system size. Finally, the k-residence time relationships were upscaled to the landscape scale using a wetland size-frequency distribution. Results suggest that small wetlands play a disproportionately large role in landscape-scale nutrient processing—50% of nitrogen removal occurs in wetlands smaller than 10^2.5 m2 in our example. Thus, given the same loss in wetland area, the nutrient retention potential lost is greater when smaller wetlands are preferentially lost from the landscape. Such findings are significant to wetland protection and restoration efforts, which have historically focused on maximizing total wetland area rather than on preserving a distribution of different wetlands sizes within a landscape.

An efficient process for wastewater treatment to mitigate free nitrous acid generation and its inhibition on biological phosphorus removal

PubMed Central

Zhao, Jianwei; Wang, Dongbo; Li, Xiaoming; Yang, Qi; Chen, Hongbo; Zhong, Yu; An, Hongxue; Zeng, Guangming

2015-01-01

Free nitrous acid (FNA), which is the protonated form of nitrite and inevitably produced during biological nitrogen removal, has been demonstrated to strongly inhibit the activity of polyphosphate accumulating organisms (PAOs). Herein we reported an efficient process for wastewater treatment, i.e., the oxic/anoxic/oxic/extended-idle process to mitigate the generation of FNA and its inhibition on PAOs. The results showed that this new process enriched more PAOs which thereby achieved higher phosphorus removal efficiency than the conventional four-step (i.e., anaerobic/oxic/anoxic/oxic) biological nutrient removal process (41 ± 7% versus 30 ± 5% in abundance of PAOs and 97 ± 0.73% versus 82 ± 1.2% in efficiency of phosphorus removal). It was found that this new process increased pH value but decreased nitrite accumulation, resulting in the decreased FNA generation. Further experiments showed that the new process could alleviate the inhibition of FNA on the metabolisms of PAOs even under the same FNA concentration. PMID:25721019

Removal of nutrients in denitrification system using coconut coir fibre for the biological treatment of aquaculture wastewater.

PubMed

Manoj, Valsa Remony; Vasudevan, Namasivayam

2012-03-01

Ideal bacterial support medium for fixed film denitrification processes/bioreactors must be inexpensive, durable and possess large surface area with sufficient porosity. The present study has been focussed on removing nitrate nitrogen at two different nitrate nitrogen loading rates (60 (NLR I) and 120 (NLR II) mg l(-1)) from simulated aquaculture wastewater. Coconut coir fibre and a commercially available synthetic reticulated plastic media (Fujino Spirals) were used as packing medium in two independent upflow anaerobic packed bed column reactors. Removal of nitrate nitrogen was studied in correlation with other nutrients (COD, TKN, dissolved orthophosphate). Maximum removal of 97% at NLR-I and 99% at NLR - II of nitrate nitrogen was observed in with either media. Greater consistency in the case of COD removal of upto 81% was observed at NLR II where coconut coir was used as support medium compared to 72% COD removal by Fujino Spirals. The results observed indicate that the organic support medium is just as efficient in nitrate nitrogen removal as conventionally used synthetic support medium. The study is important as it specifically focuses on denitrification of aquaculture wastewater using cheaper organic support medium in anoxic bioreactors for the removal of nitrate nitrogen; which is seldom addressed as a significant problem.

Implication of two in-stream processes in the fate of nutrients discharged by sewage system into a temporary river.

PubMed

David, Arthur; Perrin, Jean-Louis; Rosain, David; Rodier, Claire; Picot, Bernadette; Tournoud, Marie-George

2011-10-01

The aim of this study was to better understand the fate of nutrients discharged by sewage treatment plants into an intermittent Mediterranean river, during a low-flow period. Many pollutants stored in the riverbed during the low-flow period can be transferred to the downstream environments during flood events. The study focused on two processes that affect the fate and the transport of nutrients, a physical process (retention in the riverbed sediments) and a biological process (denitrification). A spatial campaign was carried out during a low-flow period to characterize the nutrient contents of both water and sediments in the Vène River. The results showed high nutrient concentrations in the water column downstream of the treated wastewater disposal (up to 13,315 μg N/L for ammonium and 2,901 μg P/L for total phosphorus). Nutrient concentrations decreased rapidly downstream of the disposal whereas nutrient contents in the sediments increased (up to 1,898 and 784 μg/g for total phosphorus and Kjeldahl nitrogen, respectively). According to an in situ experiment using sediment boxes placed in the riverbed for 85 days, we estimated that the proportion of nutrients trapped in the sediments represents 25% (respectively 10%) of phosphorus (respectively nitrogen) loads lost from the water column. In parallel, laboratory tests indicated that denitrification occurred in the Vène River, and we estimated that denitrification likely coupled to nitrification processes during the 85 days of the experiment was significantly involved in the removal of nitrogen loads (up to 38%) from the water column and was greater than accumulation processes.

The effects of bird use on nutrient removal in a constructed wastewater-treatment wetland

USGS Publications Warehouse

Andersen, D.C.; Sartoris, J.J.; Thullen, J.S.; Reusch, P.G.

2003-01-01

A 9.9-ha constructed wetland designed to reduce nitrogen in municipal wastewater following conventional secondary treatment began operating in southern California's San Jacinto Valley in September 1994. The wetland incorporated zones of bulrush (Schoenoplectus acutus and S. californicus) for effluent treatment, plus areas of 1.8-m deep open water and other features to benefit wintering waterfowl. A one-year long program to monitor bird use and evaluate their contribution to loadings of nitrogen and phosphorus was initiated seven months later and a second, four-month long period of monitoring was initiated after a 20-month hiatus. Daily bird use peaked at nearly 12,000 individuals during the second period. Estimates of maximum daily nitrogen and phosphorus input by birds were 139 g N ha−1 day−1 and 56 g P ha−1 day−1. Following a reconfiguration of the wetland that increased the area of open water, a third year-long period of monitoring was initiated in September 2000. Estimated maximum daily loading attributable to birds during this period reached 312 g N ha−1 day−1 and 124 g P ha−1 day−1. These levels represent only 2.6% and 7.0%, respectively, of the mean daily loads of N and P in inflow water from the wastewater-treatment plant. Wintering waterfowl contributed the most to nutrient loading, but the numerically dominant species was the colonial Red-winged Blackbird (Agelaius phoeniceus). The wetland's nutrient-removal efficiency was negatively correlated to bird loading. However, the greatest bird loading occurred during November to March, when winter conditions would reduce microbial nutrient-removal processes and plant uptake in the wetland. Multiple regression analysis indicated that variation in nutrient removal efficiency over a one-year period was best explained by wetland water temperature (R2 = 0.21) and that little additional insight was gained by adding bird loading and inflow nutrient load data (R2 = 0.22). This case study supports the concept that a constructed wetland can be designed both to reduce nutrients in municipal wastewater and to provide habitat for wetland birds.

Nutrient removal and starch production through cultivation of Wolffia arrhiza.

PubMed

Fujita, M; Mori, K; Kodera, T

1999-01-01

Wolffia arrhiza, a small weed found mostly in tropical and subtropical water environments, exhibits a high growth rate and consequently absorbs large amounts of nitrogen and phosphorus. Its vegetative frond contains 40% protein on a dry weight basis and its turion, which is the dormant form, has a similar starch content. The applicability of this weed to nutrient removal from secondary-treated waste water combined with starch resource production was evaluated. The nitrogen and phosphorus removal capabilities of the vegetative frond and the optimal conditions for inducing of the formation of turions from harvested biomass of vegetative fronds for the production of starch were investigated using artificial nutrient solutions. The vegetative frond showed high contents of nitrogen (6-7% of the total dry weight) and phosphorus (1-2% of the total dry weight). The nutrient removal rates of the vegetative frond were estimated to be 126 mg-N/m(2)/d and 38 mg-P/m(2)/d under a continuous flow condition. For turion formation from the vegetative fronds, a low nutrient concentration and a high plant density were most effective. Under the optimum conditions, the starch production rate was estimated to be 6 g-starch/m(2) (nutrient removal tank)/d.

Soil Biogeochemistry in a Changing Climate: Effect of Snow Removal

NASA Astrophysics Data System (ADS)

Patel, K.; Tatariw, C.; Fernandez, I. J.; Macrae, J. D.; Ohno, T.

2016-12-01

Winter snowpack plays an important role in ecosystem functioning, thermally insulating the subnivean soil from freezing temperatures. Wintertime microbial mineralization of organic material results in accumulation of nutrients under the snowpack, which are available post-melt for plant root uptake. The northeastern United States has experienced declining snow accumulation, and climate models project this trend will continue in the future. Intermittent and reduced snow cover increases soil freezing and frost damage, which can have implications on spring nutrient availability and forest productivity. We conducted a 2-year snow removal experiment in the Dwight B. DeMeritt Forest at the University of Maine to study subnivean winter processes, and to examine the effect of a decreased snowpack on soil winter and spring biogeochemistry. Surface organic soils were collected during winter and spring of 2015 and 2016, years with sharply contrasting snow accumulation, to track temporal changes in nutrient dynamics as the system evolved from under the snowpack. Laboratory extractions and incubations were performed to quantify the inorganic available nitrogen, dissolved organic carbon (DOC), and potential net N-mineralization (PNNM) in field moist soils. Snow removal resulted in decreased winter soil temperatures (2-8°C colder than the reference plots). There was an increased incidence of rain-on-soil events in the winter, forming concrete frost. Freeze-thaw cycles in the treatment plots resulted in higher NH4-N and DOC concentrations, but lower PNNM, compared to the reference plots. Treatment effects on DOC and NH4-N concentrations were not seen in the spring, although the effects on PNNM persisted. Our findings demonstrated that freeze-thaw cycles play an important role in the timing and magnitude of soil nutrient availability during the vernal transition. Understanding these processes becomes increasingly important when defining forest ecosystem response to a changing climate.

Optimization and performance evaluation for nutrient removal from palm oil mill effluent wastewater using microalgae

NASA Astrophysics Data System (ADS)

Ibrahim, Raheek I.; Wong, Z. H.; Mohammad, A. W.

2015-04-01

Palm oil mill effluent (POME) wastewater was produced in huge amounts in Malaysia, and if it discharged into the environment, it causes a serious problem regarding its high content of nutrients. This study was devoted to POME wastewater treatment with microalgae. The main objective was to find the optimum conditions (retention time, and pH) in the microalgae treatment of POME wastewater considering retention time as a most important parameter in algae treatment, since after the optimum conditions there is a diverse effect of time and pH and so, the process becomes costly. According to our knowledge, there is no existing study optimized the retention time and pH with % removal of nutrients (ammonia nitrogen NH3-N, and orthophosphorous PO43-) for microalgae treatment of POME wastewater. In order to achieve with optimization, a central composite rotatable design with a second order polynomial model was used, regression coefficients and goodness of fit results in removal percentages of nutrients (NH3-N, and PO43-) were estimated.WinQSB technique was used to optimize the surface response objective functionfor the developed model. Also experiments were done to validate the model results.The optimum conditions were found to be 18 day retention time for ammonia nitrogen, and pH of 9.22, while for orthophosphorous, 15 days were indicated as the optimum retention time with a pH value of 9.2.

Recovery of ammonia in digestates of calf manure through a struvite precipitation process using unconventional reagents.

PubMed

Siciliano, A; De Rosa, S

2014-01-01

Land spreading of digestates causes the discharge of large quantities of nutrients into the environment, which contributes to eutrophication and depletion of dissolved oxygen in water bodies. For the removal of ammonia nitrogen, there is increasing interest in the chemical precipitation of struvite, which is a mineral that can be reused as a slow-release fertilizer. However, this process is an expensive treatment of digestate because large amounts of magnesium and phosphorus reagents are required. In this paper, a struvite precipitation-based process is proposed for an efficient recovery of digestate nutrients using low-cost reagents. In particular, seawater bittern, a by-product of marine salt manufacturing and bone meal, a by-product of the thermal treatment of meat waste, have been used as low-cost sources of magnesium and phosphorus, respectively. Once the operating conditions are defined, the process enables the removal of more than 90% ammonia load, the almost complete recovery of magnesium and phosphorus and the production of a potentially valuable precipitate containing struvite crystals.

Develop Recovery Systems for Separations of Salts from Process Streams for use in Advanced Life Support System

NASA Technical Reports Server (NTRS)

Colon, Guillermo

1998-01-01

The main objectives of this project were the development of a four-compartment electrolytic cell using high selective membranes to remove nitrate from crop residue leachate and convert it to nitric acid, and the development of an six compartment electrodialysis cell to remove selectively sodium from urine wastes. The recovery of both plant inedible biomass and human wastes nutrients to sustain a biomass production system are important aspects in the development of a controlled ecological life support system (CELSS) to provide the basic human needs required for life support during long term space missions. A four-compartment electrolytic cell has been proposed to remove selectively nitrate from crop residue and to convert it to nitric acid, which is actually used in the NASA-KSC Controlled Ecological Life Support System to control the pH of the aerobic bioreactors and biomass production chamber. Human activities in a closed system require large amount of air, water and minerals to sustain life and also generate wastes. Before using human wastes as nutrients, these must be treated to reduce organic content and to remove some minerals which have adverse effects on plant growth. Of all the minerals present in human urine, sodium chloride (NACl) is the only one that can not be used as nutrient for most plants. Human activities also requires sodium chloride as part of the diet. Therefore, technology to remove and recover sodium chloride from wastes is highly desirable. A six-compartment electrodialysis cell using high selective membranes has been proposed to remove and recover NaCl from human urine.

Elucidating the impacts of initial supersaturation and seed crystal loading on struvite precipitation kinetics, fines production, and crystal growth.

PubMed

Agrawal, Shantanu; Guest, Jeremy S; Cusick, Roland D

2018-04-01

To reduce intra-plant nutrient cycling, and recover phosphorus (P) fertilizers from nutrient-rich sidestreams, wastewater utilities increasingly elect to employ struvite precipitation processes without a clear understanding of the inherent tradeoffs associated with specific design and operating decisions. Specifically, the impact of reactor conditions on struvite crystallization rate, and distribution between formation of fines particles and secondary growth onto large diameter seed crystals represent critical knowledge gaps limiting the predictive capabilities of existing process models. In this work, the relative impacts of initial supersaturation (S i ), and seed loading, on P removal kinetics, and struvite solids distribution were investigated. In experiments conducted at different levels of initial supersaturation (1.7-2.4) and seed loading (0-25 g L -1 ), struvite fines represented the majority of phosphate solids formed in 10 of 12 conditions. While total P removal was dependent on S i , and primarily attributed to formation of fines, the concentration of struvite seed granules had a significant impact on the rate of P removal. Struvite seed granules increased the rate of precipitation by reducing induction time of primary nucleation of struvite fines. Secondary crystal growth represented the majority of struvite solids formed at high seed loading and low S i , but presented the tradeoff of low total removal and low rate of removal. To convey the significance of these findings on process modeling, we show how a prominent kinetic model with a first-order dependency on solid struvite concentration over-predicts P removal rate when total mass is dominated by large diameter seeds (0.9 mm). This works reveals the critical role of struvite fines in P removal, and highlights the need to account for their production and kinetic importance in struvite process design and operation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Efficacy of Chlorella pyrenoidosa and Scenedesmus abundans for Nutrient Removal in Rice Mill Effluent (Paddy Soaked Water).

PubMed

Abinandan, S; Bhattacharya, Ribhu; Shanthakumar, S

2015-01-01

Microalgae are product of sustainable development owing to its ability to treat variety of wastewater effluents and thus produced biomass can serve as value added product for various commercial applications. This paper deals with the cultivation of microalgae species namely Chlorella pyrenoidosa and Scenedesmus abundans in rice mill effluent (i.e., paddy soaked water) for nutrient removal. In order to investigate the nutrient removal capability, microalgae are subjected to cultivation in both raw and autoclaved samples. The maximum phosphate removal by Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 98.3% and 97.6%, respectively, whereas, the removal of ammoniacal nitrogen by Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 92% and 90.3%, respectively. The growth (measured in terms of chlorophyll content) of Scenedesmus abundans and Chlorella pyrenoidosa in raw sample was 3.88 mg/l and 5.55 mg/l, respectively. The results indicate the suitability of microalgae cultivation in rice mill effluent treatment for nutrient removal.

Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration

USGS Publications Warehouse

Haukos, David A.; Johnson, Lacrecia A.; Smith, Loren M.; McMurry, Scott T.

2016-01-01

Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30–60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands.

Use of a dynamic simulation model to understand nitrogen cycling in the middle Rio Grande, NM.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meixner, Tom; Tidwell, Vincent Carroll; Oelsner, Gretchen

2008-08-01

Water quality often limits the potential uses of scarce water resources in semiarid and arid regions. To best manage water quality one must understand the sources and sinks of both solutes and water to the river system. Nutrient concentration patterns can identify source and sink locations, but cannot always determine biotic processes that affect nutrient concentrations. Modeling tools can provide insight into these large-scale processes. To address questions about large-scale nitrogen removal in the Middle Rio Grande, NM, we created a system dynamics nitrate model using an existing integrated surface water--groundwater model of the region to evaluate our conceptual modelsmore » of uptake and denitrification as potential nitrate removal mechanisms. We modeled denitrification in groundwater as a first-order process dependent only on concentration and used a 5% denitrification rate. Uptake was assumed to be proportional to transpiration and was modeled as a percentage of the evapotranspiration calculated within the model multiplied by the nitrate concentration in the water being transpired. We modeled riparian uptake as 90% and agricultural uptake as 50% of the respective evapotranspiration rates. Using these removal rates, our model results suggest that riparian uptake, agricultural uptake and denitrification in groundwater are all needed to produce the observed nitrate concentrations in the groundwater, conveyance channels, and river as well as the seasonal concentration patterns. The model results indicate that a total of 497 metric tons of nitrate-N are removed from the Middle Rio Grande annually. Where river nitrate concentrations are low and there are no large nitrate sources, nitrate behaves nearly conservatively and riparian and agricultural uptake are the most important removal mechanisms. Downstream of a large wastewater nitrate source, denitrification and agricultural uptake were responsible for approximately 90% of the nitrogen removal.« less

Nutrient Dynamics In Flooded Wetlands. I: Model Development

EPA Science Inventory

Wetlands are rich ecosystems recognized for ameliorating floods, improving water quality and providing other ecosystem benefits. In this part of a two-paper sequel, we present a relatively detailed process-based model for nitrogen and phosphorus retention, cycling and removal in...

Utilizing Anaerobically Digested Dairy Manure for the Cultivation of Duckweed for Biomass Production, Nutrient Assimilation, and Sugar Production

NASA Astrophysics Data System (ADS)

Kruger, Kevin C.

Nutrient management methods are needed to provide sustainable operation to livestock production that balance the costs of operation and maintenance. Cultivating duckweed on dairy wastes is considered an effective way of nutrient uptake and cycling. Duckweed cultivation has been implemented on nutrient management systems, such as constructed wetlands and waste stabilization ponds that use both domestic and swine wastewater. The objectives of this study were to (1) identify a nutrient concentration and duckweed strain that rapidly produces biomass, (2) removes nutrient content from anaerobically digested dairy manure, and (3) produces starch from nutrient starvation. To complete these objectives, this study targeted estimating growth and nutrient rate constants as well as starch yield of duckweed under different cultivation conditions. The strains of duckweed, Landoltia punctata 0128, Lemna gibba 7589, and Lemna minuta 9517 were identified as the promising candidates for their high levels of nutrient uptake, starch accumulation, and biomass production. The growth rate of the duckweed strain was assessed based on the effects of temperature, pH, dissolved oxygen, light intensity, nutrient concentration, and biomass accumulation. The nutrient uptake through duckweed cultivation on the anaerobically digested (AD) dairy manure, characterized by the changes of total nitrogen (TN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and ortho-phosphate-phosphorus (o-PO 4-P), was assessed in four nutrient dilution ratios 1:5, 1:13, 1:18, and 1:27 v/v at two light intensities of 10,000 and 3,000 lux to model seasonal variation. The duckweed strain that exhibited the best biomass production, nutrient removal and starch accumulation was Landoltia punctata 0128 at a dilution ratio of 1:27 at a light intensity of 10,000 lux. The growth rate constant established from zero order kinetics for Landoltia punctata 0128 was 13.3 gm-2d-1. The rate constants for nutrient recovery were 0.122 d-1 of TN, 0.136 d -1 of TKN, 0.145 d-1 of TP, and 0.173d-1 of o-PO4-P. The batch efficiency of cultivation for Landoltia punctata 0128 on dilution ratio 1:27, in terms of nutrient uptake was 38% m/m in relation to the total nitrogen removed. The starch yield was measured at 30% w/w for Landoltia punctata 0128 after the nutrient starvation process. Due to its ability to reduce nutrients from AD dairy manure, accumulate biomass at a rapid growth rate, and accumulate a high yield of starch, Landoltia punctata 0128 has great potential to become a preferred choice for nutrient recovery and biomass and bioethanol production.

Model-based evaluation of two BNR processes--UCT and A2N.

PubMed

Hao, X; Van Loosdrecht, M C; Meijer, S C; Qian, Y

2001-08-01

The activity of denitrifying P-accumulating bacteria (DPB) has been verified to exist in most WWTPs with biological nutrient removal (BNR). The modified UCT process has a high content of DPB. A new BNR process with a two-sludge system named A2N was especially developed to exploit denitrifying dephosphatation. With the identical inflow and effluent standards, an existing full-scale UCT-type WWTP and a designed A2N process were evaluated by simulation. The used model is based on the Delft metabolical model for bio-P removal and ASM2d model for COD and N removal. Both processes accommodate denitrifying dephosphatation, but the A2N process has a more stable performance in N removal. Although excess sludge is increased by 6%, the A2N process leads to savings of 35, 85 and 30% in aeration energy, mixed liquor internal recirculation and land occupation respectively, as compared to the UCT process. Low temperature has a negative effect on growth of poly-P bacteria, which becomes to especially appear in the A2N process.

Biotechnological potential of Synechocystis salina co-cultures with selected microalgae and cyanobacteria: Nutrients removal, biomass and lipid production.

PubMed

Gonçalves, Ana L; Pires, José C M; Simões, Manuel

2016-01-01

Cultivation of microalgae and cyanobacteria has been the focus of several research studies worldwide, due to the huge biotechnological potential of these photosynthetic microorganisms. However, production of these microorganisms is still not economically viable. One possible alternative to improve the economic feasibility of the process is the use of consortia between microalgae and/or cyanobacteria. In this study, Chlorella vulgaris, Pseudokirchneriella subcapitata and Microcystis aeruginosa were co-cultivated with Synechocystis salina to evaluate how dual-species cultures can influence biomass and lipid production and nutrients removal. Results have shown that the three studied consortia achieved higher biomass productivities than the individual cultures. Additionally, nitrogen and phosphorus consumption rates by the consortia provided final concentrations below the values established by European Union legislation for these nutrients. In the case of lipid productivities, higher values were determined when S. salina was co-cultivated with P. subcapitata and M. aeruginosa. Copyright © 2015 Elsevier Ltd. All rights reserved.

Integrated campus sewage treatment and biomass production by Scenedesmus quadricauda SDEC-13.

PubMed

Han, Lin; Pei, Haiyan; Hu, Wenrong; Jiang, Liqun; Ma, Guixia; Zhang, Shuo; Han, Fei

2015-01-01

The notion of wastewater treatment combined with biomass production is potential and prospective. Campus sewage was utilized twice in procession to cultivate the newly isolated microalgae Scenedesmus quadricauda SDEC-13. Nutrients was efficiently removed with the phosphorus and nitrogen removal efficiency nearly 100% and more than 70% respectively in twice use of campus sewage. Ammonium was consumed rapidly within five days in 1st use. There was no significant difference in the lipid and protein content but distinct difference in their respective productivity which is ascribed to the lower biomass productivity caused by limited nutrients in 2nd use. The diverse nutrient concentration in twice use of campus sewage and BG-11 had effects on the composition of fatty acids and amino acids. SDEC-13 performed better biodiesel quality compared with BG-11 medium and produced high quality protein when cultivated in campus sewage. Finally, the campus sewage after twice use reached the corresponding discharge standard. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fungi-based treatment of brewery wastewater-biomass production and nutrient reduction.

PubMed

Hultberg, M; Bodin, H

2017-06-01

The beer-brewing process produces high amounts of nutrient-rich wastewater, and the increasing number of microbreweries worldwide has created a need for innovative solutions to deal with this waste. In the present study, fungal biomass production and the removal of organic carbon, phosphorus and nitrogen from synthetic brewery wastewater were studied. Different filamentous fungi with a record of safe use were screened for growth, and Trametes versicolor, Pleurotus ostreatus and Trichoderma harzianum were selected for further work. The highest biomass production, 1.78 ± 0.31 g L -1 of dry weight, was observed when P. ostreatus was used for the treatment, while T. harzianum demonstrated the best capability for removing nutrients. The maximum reduction of chemical oxygen demand, 89% of the initial value, was observed with this species. In the removal of total nitrogen and phosphorus, no significant difference was observed between the species, while removal of ammonium varied between the strains. The maximum reduction of ammonium, 66.1% of the initial value, was also found in the T. harzianum treatment. It can be concluded that all treatments provided significant reductions in all water-quality parameters after 3 days of growth and that the utilisation of filamentous fungi to treat brewery wastewater, linked to a deliberate strategy to use the biomass produced, has future potential in a bio-based society.

Improved nutrient removal using in situ continuous on-line sensors with short response time.

PubMed

Ingildsen, P; Wendelboe, H

2003-01-01

Nutrient sensors that can be located directly in the activated sludge processes are gaining in number at wastewater treatment plants. The in situ location of the sensors means that they can be located close to the processes that they aim to control and hence are perfectly suited for automatic process control. Compared to the location of automatic analysers in the effluent from the sedimentation reactors the in situ location means a large reduction in the response time. The settlers typically work as a first-order delay on the signal with a retention time in the range of 4-12 hours depending on the size of the settlers. Automatic process control of the nitrogen and phosphorus removal processes means that considerable improvements in the performance of aeration, internal recirculation, carbon dosage and phosphate precipitation dosage can be reached by using a simple control structure as well as simple PID controllers. The performance improvements can be seen in decreased energy and chemicals consumption and less variation in effluent concentrations of ammonium, total nitrogen and phosphate. Simple control schemes are demonstrated for the pre-denitrification and the post precipitation system by means of full-scale plant experiments and model simulations.

Low elevation inland habitats of the Willamette River floodplain support enhanced denitrification

EPA Science Inventory

Floodplain nitrate removal via denitrification in sediment provides an important ecosystem service that may be a valuable sink for nitrate pollution. At this time, much floodplain restoration is taking place with little consideration for in-situ nutrient processing, necessitating...

Removal of phosphate from greenhouse wastewater using hydrated lime.

PubMed

Dunets, C Siobhan; Zheng, Youbin

2014-01-01

Phosphate (P) contamination in nutrient-laden wastewater is currently a major topic of discussion in the North American greenhouse industry. Precipitation of P as calcium phosphate minerals using hydrated lime could provide a simple, inexpensive method for retrieval. A combination of batch experiments and chemical equilibrium modelling was used to confirm the viability of this P removal method and determine lime addition rates and pH requirements for greenhouse wastewater of varying nutrient compositions. Lime: P ratio (molar ratio of CaMg(OH)₄: PO₄‒P) provided a consistent parameter for estimating lime addition requirements regardless of initial P concentration, with a ratio of 1.5 providing around 99% removal of dissolved P. Optimal P removal occurred when lime addition increased the pH from 8.6 to 9.0, suggesting that pH monitoring during the P removal process could provide a simple method for ensuring consistent adherence to P removal standards. A Visual MINTEQ model, validated using experimental data, provided a means of predicting lime addition and pH requirements as influenced by changes in other parameters of the lime-wastewater system (e.g. calcium concentration, temperature, and initial wastewater pH). Hydrated lime addition did not contribute to the removal of macronutrient elements such as nitrate and ammonium, but did decrease the concentration of some micronutrients. This study provides basic guidance for greenhouse operators to use hydrated lime for phosphate removal from greenhouse wastewater.

Nutrient removal by prairie filter strips in agricultural landscapes

Treesearch

X. Zhou; M.J. Helmers; H. Asbjornsen; R. Kolka; M.D. Tomer; R.M. Cruse

2014-01-01

Nitrogen (N) and phosphorus (P) from agricultural landscapes have been identified as primary sources of excess nutrients in aquatic systems. The main objective of this study was to evaluate the effectiveness of prairie filter strips (PFS) in removing nutrients from cropland runoff in 12 small watersheds in central Iowa. Four treatments with PFS of different spatial...

Contribution of water hyacinth (Eichhornia crassipes (Mart.) Solms) grown under different nutrient conditions to Fe-removal mechanisms in constructed wetlands.

PubMed

Jayaweera, Mahesh W; Kasturiarachchi, Jagath C; Kularatne, Ranil K A; Wijeyekoon, Suren L J

2008-05-01

Severe contamination of water resources including groundwater with iron (Fe) due to various anthropogenic activities has been a major environmental problem in industrial areas of Sri Lanka. Hence, the use of the obnoxious weed, water hyacinth (Eichhornia crassipes (Mart.) Solms) in constructed wetlands (floating aquatic macrophyte-based plant treatment systems) to phytoremediate Fe-rich wastewaters seems to be an appealing option. Although several studies have documented that hyacinths are good metal-accumulating plants none of these studies have documented the ability of this plant grown under different nutrient conditions to remove heavy metals from wastewaters. This paper, therefore, reports the phytoremediation efficiencies of water hyacinth grown under different nutrient conditions for Fe-rich wastewaters in batch-type constructed wetlands. This study was conducted for 15 weeks after 1-week acclimatization by culturing young water hyacinth plants (average height of 20+/-2cm) in 590L capacity fiberglass tanks under different nutrient concentrations of 1-fold [28 and 7.7mg/L of total nitrogen (TN) and total phosphorous (TP), respectively], 2-fold, 1/2-fold, 1/4-fold and 1/8-fold with synthetic wastewaters containing 9.27Femg/L. Another set-up of hyacinths containing only Fe as a heavy metal but without any nutrients (i.e., 0-fold) was also studied. A mass balance was carried out to investigate the phytoremediation efficiencies and to determine the different mechanisms governing Fe removal from the wastewaters. Fe removal was largely due to phytoremediation mainly through the process of rhizofiltration and chemical precipitation of Fe2O3 and FeOH3 followed by flocculation and sedimentation. However, chemical precipitation was more significant especially during the first 3 weeks of the study. Plants grown in the 0-fold set-up showed the highest phytoremediation efficiency of 47% during optimum growth at the 6th week with a highest accumulation of 6707Femg/kg dry weight. Active effluxing of Fe back to the wastewater at intermittent periods and with time was a key mechanism of avoiding Fe phytotoxicity in water hyacinth cultured in all set-ups. Our study elucidated that water hyacinth grown under nutrient-poor conditions are ideal to remove Fe from wastewaters with a hydraulic retention time of approximately 6 weeks.

Lipid production from tapioca wastewater by culture of Scenedesmus sp. with simultaneous BOD, COD and nitrogen removal

NASA Astrophysics Data System (ADS)

Romaidi; Hasanudin, Muhammad; Kholifah, Khusnul; Maulidiyah, Alik; Putro, Sapto P.; Kikuchi, Akira; Sakaguchi, Toshifumi

2018-05-01

The use of microalgae to produce biodiesel or possibly remove nutrients from industrial wastewater has gained important attention during recent years due to their photosynthetic rate and its versatile nature to grow in various wastewater systems. In this study, a microalgae, Scenedesmus sp., was cultured to enhance the lipid production and nutrients removal from tapioca wastewater sample. To assess lipid production, Scenedesmus sp. was cultured in different concentration of tapioca wastewater sample (from 0 to 100 %), and nutrient removal including BOD, COD, NH4, NO2, NO3 level by Scenedesmus sp. was assessed in 100% of tapioca wastewater culture. After 8 days of culture, it was found out that 50% of tapioca wastewater sample resulted in highest concentration of lipid content than that of the other concentrations. The level of environment indicator as nutrient removal such as BOD, COD, NH4, NO2, NO3 were also decreased up to 74%, 72%, 95%, 91%, and 91%, respectively. The pH condition changed from initial condition acidic (pH: 4) to neutral or basic condition (pH: 7-8) as recommended in wastewater treatment system. This research provided a novel approach and achieved efficient simultaneous lipid production and nutrients removal from tapioca wastewater sample by Scenedesmus’s culture system.

Pilot plant demonstration of stable and efficient high rate biological nutrient removal with low dissolved oxygen conditions.

PubMed

Keene, Natalie A; Reusser, Steve R; Scarborough, Matthew J; Grooms, Alan L; Seib, Matt; Santo Domingo, Jorge; Noguera, Daniel R

2017-09-15

Aeration in biological nutrient removal (BNR) processes accounts for nearly half of the total electricity costs at many wastewater treatment plants. Even though conventional BNR processes are usually operated to have aerated zones with high dissolved oxygen (DO) concentrations, recent research has shown that nitrification can be maintained using very low-DO concentrations (e.g., below 0.2 mg O 2 /L), and therefore, it may be possible to reduce energy use and costs in BNR facilities by decreasing aeration. However, the effect of reduced aeration on enhanced biological phosphorus removal (EBPR) is not understood. In this study, we investigated, at the pilot-scale level, the effect of using minimal aeration on the performance of an EBPR process. Over a 16-month operational period, we performed stepwise decreases in aeration, reaching an average DO concentration of 0.33 mg O 2 /L with stable operation and nearly 90% phosphorus removal. Under these low-DO conditions, nitrification efficiency was maintained, and nearly 70% of the nitrogen was denitrified, without the need for internal recycling of high nitrate aeration basin effluent to the anoxic zone. At the lowest DO conditions used, we estimate a 25% reduction in energy use for aeration compared to conventional BNR operation. Our improved understanding of the efficiency of low-DO BNR contributes to the global goal of reducing energy consumption during wastewater treatment operations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparison between coagulation-flocculation and ozone-flotation for Scenedesmus microalgal biomolecule recovery and nutrient removal from wastewater in a high-rate algal pond.

PubMed

Oliveira, Gislayne Alves; Carissimi, Elvis; Monje-Ramírez, Ignacio; Velasquez-Orta, Sharon B; Rodrigues, Rafael Teixeira; Ledesma, María Teresa Orta

2018-07-01

The removal of nutrients by Scenedesmus sp. in a high-rate algal pond, and subsequent algal separation by coagulation-flocculation or flotation with ozone to recover biomolecules, were evaluated. Cultivation of Scenedesmus sp. in wastewater resulted in complete NH 3 -H removal, plus 93% total nitrogen and 61% orthophosphate removals. Ozone-flotation obtained better water quality results than coagulation-flocculation for most parameters (NH 3 -N, NTK, nitrate and nitrite) except orthophosphate. Ozone-flotation, also produced the highest recovery of lipids, carbohydrates and proteins which were 0.32 ± 0.03, 0.33 ± 0.025 and 0.58 ± 0.014 mg/mg of biomass, respectively. In contrast, there was a low lipid extraction of 0.21 mg of lipids/mg of biomass and 0.12-0.23 mg of protein/mg of biomass in the coagulation-flocculation process. In terms of biomolecule recovery and water quality, ozone showed better results than coagulation-flocculation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Extracellular enzymatic activity of two hydrolases in wastewater treatment for biological nutrient removal.

PubMed

Berrio-Restrepo, Jorge Mario; Saldarriaga, Julio César; Correa, Mauricio Andrés; Aguirre, Néstor Jaime

2017-10-01

Due to the complex nature of the wastewater (both domestic and non-domestic) composition, biological processes are widely used to remove nutrients, such as carbon (C), nitrogen (N), and phosphorous (P), which cause instability and hence contribute to the damage of water bodies. Systems with different configurations have been developed (including anaerobic, anoxic, and aerobic conditions) for the joint removal of carbon, nitrogen, and phosphorus. The goal of this research is to evaluate the extracellular activity of β-glucosidase and phosphatase enzymes in a University of Cape Town (UCT) system fed with two synthetic wastewaters of different molecular complexity. Both types of waters have medium strength characteristics similar to those of domestic wastewater with a mean C/N/P ratio of 100:13:1. The operation parameters were hydraulic retention time (HRT) of 10 h, solid retention time (SRT) of 12 days, mean concentration of the influent in terms of chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and total phosphorus (TP) of 600, 80, and 6 mg/L, respectively. According to the results obtained, statistically significant differences have been found in the extracellular enzyme activities with the evaluated wastewaters and in the units comprising the treatment system in some of the cases. An analysis of principal components showed that the extracellular enzymatic activity has been correlated to nutrient concentration in wastewater, biomass concentration in the system, and metabolic conditions of treatment phases. Additionally, this research has allowed determining an inverse relationship between wastewater biodegradability and the extracellular enzyme activity of β-glucosidase and phosphatase. These results highlight the importance of including the analysis of biomass biochemical characteristics as control methods in wastewater treatment systems for the nutrient removal.

Coupled nutrient removal and biomass production with mixed algal culture: impact of biotic and abiotic factors.

PubMed

Su, Yanyan; Mennerich, Artur; Urban, Brigitte

2012-08-01

The influence of biotic (algal inoculum concentration) and abiotic factors (illumination cycle, mixing velocity and nutrient strength) on the treatment efficiency, biomass generation and settleability were investigated with selected mixed algal culture. Dark condition led to poor nutrient removal efficiency. No significant difference in the N, P removal and biomass settleability between continuous and alternating illumination was observed, but a higher biomass generation capability for the continuous illumination was obtained. Different mixing velocity led to similar phosphorus removal efficiencies (above 98%) with different retention times. The reactor with 300 rpm mixing velocity had the best N removal capability. For the low strength wastewater, the N rates were 5.4±0.2, 9.1±0.3 and 10.8±0.3 mg/l/d and P removal rates were 0.57±0.03, 0.56±0.03 and 0.72±0.05 mg/l/d for reactors with the algal inoculum concentration of 0.2, 0.5 and 0.8 g/l, respectively. Low nutrient removal efficiency and poor biomass settleability were obtained for high strength wastewater. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of temperature, algae biomass and ambient nutrient on the absorption of dissolved nitrogen and phosphate by Rhodophyte Gracilaria asiatica

NASA Astrophysics Data System (ADS)

Du, Rongbin; Liu, Liming; Wang, Aimin; Wang, Yongqiang

2013-03-01

Gracilaria asiatica, being highly efficient in nutrient absorption, is cultivated in sea cucumber ponds to remove nutrients such as nitrogen and phosphate. It was cultured in a laboratory simulating field conditions, and its nutrient absorption was measured to evaluate effects of environmental conditions. Ammonia nitrogen (AN), nitrate nitrogen (NN), total inorganic nitrogen (TIN), and soluble reactive phosphorus (SRP) uptake rate and removal efficiency were determined in a 4×2 factorial design experiment in water temperatures ( T) at 15°C and 25°C, algae biomass (AB) at 0.5 g/L and 1.0 g/L, total inorganic nitrogen (TIN) at 30 μmol/L and 60 μmol/L, and soluble reactive phosphorus (SRP) at 3 and 6 μmol/L. AB and ambient TIN or SRP levels significantly affected uptake rate and removal efficiency of AN, NN, TIN, and SRP ( P< 0.001). G. asiatica in AB of 0.5 g/L showed higher uptake rate and lower removal efficiency relative to that with AB of 1.0 g/L. Nitrogen and phosphorus uptake rate rose with increasing ambient nutrient concentrations; nutrient removal efficiency decreased at higher environmental nutrient concentrations. The algae preferred to absorb AN to NN. Uptake rates of AN, NN, and SRP were significantly affected by temperature ( P < 0.001); uptake rate was higher for the 25°C group than for the 15°C group at the initial experiment stage. Only the removal efficiency of AN and SRP showed a significant difference between the two temperature groups ( P< 0.01). The four factors had significant interactive effects on absorption of N and P, implying that G. asiatica has great bioremedial potential in sea cucumber culture ponds.

Using wastewater and high-rate algal ponds for nutrient removal and the production of bioenergy and biofuels.

PubMed

Batten, David; Beer, Tom; Freischmidt, George; Grant, Tim; Liffman, Kurt; Paterson, David; Priestley, Tony; Rye, Lucas; Threlfall, Greg

2013-01-01

This paper projects a positive outcome for large-scale algal biofuel and energy production when wastewater treatment is the primary goal. Such a view arises partly from a recent change in emphasis in wastewater treatment technology, from simply oxidising the organic matter in the waste (i.e. removing the biological oxygen demand) to removing the nutrients - specifically nitrogen and phosphorus - which are the root cause of eutrophication of inland waterways and coastal zones. A growing need for nutrient removal greatly improves the prospects for using new algal ponds in wastewater treatment, since microalgae are particularly efficient in capturing and removing such nutrients. Using a spreadsheet model, four scenarios combining algae biomass production with the making of biodiesel, biogas and other products were assessed for two of Australia's largest wastewater treatment plants. The results showed that super critical water reactors and anaerobic digesters could be attractive pathway options, the latter providing significant savings in greenhouse gas emissions. Combining anaerobic digestion with oil extraction and the internal economies derived from cheap land and recycling of water and nutrients on-site could allow algal oil to be produced for less than US$1 per litre.

Denitrification and anammox in tropical aquaculture settlement ponds: an isotope tracer approach for evaluating N2 production.

PubMed

Castine, Sarah A; Erler, Dirk V; Trott, Lindsay A; Paul, Nicholas A; de Nys, Rocky; Eyre, Bradley D

2012-01-01

Settlement ponds are used to treat aquaculture discharge water by removing nutrients through physical (settling) and biological (microbial transformation) processes. Nutrient removal through settling has been quantified, however, the occurrence of, and potential for microbial nitrogen (N) removal is largely unknown in these systems. Therefore, isotope tracer techniques were used to measure potential rates of denitrification and anaerobic ammonium oxidation (anammox) in the sediment of settlement ponds in tropical aquaculture systems. Dinitrogen gas (N(2)) was produced in all ponds, although potential rates were low (0-7.07 nmol N cm(-3) h(-1)) relative to other aquatic systems. Denitrification was the main driver of N(2) production, with anammox only detected in two of the four ponds. No correlations were detected between the measured sediment variables (total organic carbon, total nitrogen, iron, manganese, sulphur and phosphorous) and denitrification or anammox. Furthermore, denitrification was not carbon limited as the addition of particulate organic matter (paired t-Test; P = 0.350, n = 3) or methanol (paired t-Test; P = 0.744, n = 3) did not stimulate production of N(2). A simple mass balance model showed that only 2.5% of added fixed N was removed in the studied settlement ponds through the denitrification and anammox processes. It is recommended that settlement ponds be used in conjunction with additional technologies (i.e. constructed wetlands or biological reactors) to enhance N(2) production and N removal from aquaculture wastewater.

Denitrification and Anammox in Tropical Aquaculture Settlement Ponds: An Isotope Tracer Approach for Evaluating N2 Production

PubMed Central

Castine, Sarah A.; Erler, Dirk V.; Trott, Lindsay A.; Paul, Nicholas A.; de Nys, Rocky; Eyre, Bradley D.

2012-01-01

Settlement ponds are used to treat aquaculture discharge water by removing nutrients through physical (settling) and biological (microbial transformation) processes. Nutrient removal through settling has been quantified, however, the occurrence of, and potential for microbial nitrogen (N) removal is largely unknown in these systems. Therefore, isotope tracer techniques were used to measure potential rates of denitrification and anaerobic ammonium oxidation (anammox) in the sediment of settlement ponds in tropical aquaculture systems. Dinitrogen gas (N2) was produced in all ponds, although potential rates were low (0–7.07 nmol N cm−3 h−1) relative to other aquatic systems. Denitrification was the main driver of N2 production, with anammox only detected in two of the four ponds. No correlations were detected between the measured sediment variables (total organic carbon, total nitrogen, iron, manganese, sulphur and phosphorous) and denitrification or anammox. Furthermore, denitrification was not carbon limited as the addition of particulate organic matter (paired t-Test; P = 0.350, n = 3) or methanol (paired t-Test; P = 0.744, n = 3) did not stimulate production of N2. A simple mass balance model showed that only 2.5% of added fixed N was removed in the studied settlement ponds through the denitrification and anammox processes. It is recommended that settlement ponds be used in conjunction with additional technologies (i.e. constructed wetlands or biological reactors) to enhance N2 production and N removal from aquaculture wastewater. PMID:22962581

Floodplain restoration increases hyporheic flow in the Yakima River Watershed, Washington

EPA Science Inventory

Hyporheic exchange between a river channel and its floodplain region assists in mediating processes such as nutrient removal and temperature regulation. Floodplain restoration in the form of levee setbacks are often carried out to improve the hyporheic exchange. In this study Lig...

The influence of residue removal and prescribed fire on distributions of forest nutrients.

Treesearch

Little; S.N.; G.O. Klock

1985-01-01

The effects of two levels of residue removal (removal of all woody material larger than 15 x 180 cm and 10 x 120 cm) on the distribution of nitrogen and sulfur on the forest site and the added effects of post-harvest prescribed fire on those distributions were studied at two sites in the Cascade Range in Oregon. Nutrients lost from increased removal of residue were...

Prevention of clogging in a biological trickle-bed reactor removing toluene from contaminated air.

PubMed

Weber, F J; Hartmans, S

1996-04-05

Removal of organic compounds like toluene from waste gases with a trickle-bed reactor can result in clogging of the reactor due to the formation of an excessive amount of biomass. We therefore limited the amount of nutrients available for growth, to prevent clogging of the reactor. As a consequence of this nutrient limitation a lower removal rate was observed. However, when a fungal culture was used to inoculate the reactor, the toluene removal rate under nutrient limiting conditions was higher. Over a period of 375 days, an average removal rate of 27 g C/(m(3) h) was obtained with the reactor inoculated with the fungal culture. From the carbon balance over the reactor and the nitrogen availability it was concluded that, under these nutrient-limited conditions, large amounts of carbohydrates are probably formed. We also studied the application of a NaOH wash to remove excess biomass, as a method to prevent clogging. Under these conditions an average toluene removal rate of 35 g C/(m(3) h) was obtained. After about 50 days there was no net increase in the biomass content of the reactor. The amount of biomass which was formed in the reactor equaled the amount removed by the NaOH wash.

Bio-augmentation and nutrient amendment decrease concentration of mercury in contaminated soil.

PubMed

Mahbub, Khandaker Rayhan; Krishnan, Kannan; Andrews, Stuart; Venter, Henrietta; Naidu, Ravi; Megharaj, Mallavarapu

2017-01-15

Four mercury (Hg) contaminated soils with different pH (7.6, 8.5, 4.2 and 7.02) and total organic carbon contents (2.1, 2.2, 4 and 0.9%) were subjected to bioremediation utilizing a Hg volatilizing bacterial strain Sphingobium SA2 and nutrient amendment. In a field with ~280mg/kgHg, 60% of Hg was removed by bio-augmentation in 7days, and the removal was improved when nutrients were added. Whereas in artificially spiked soils, with ~100mg/kgHg, removal due to bio-augmentation was 33 to 48% in 14days. In the field contaminated soil, nutrient amendment alone without bio-augmentation removed 50% of Hg in 28days. Nutrient amendment also had an impact on Hg remediation in the spiked soils, but the best results were obtained when the strain and nutrients both were applied. The development of longer root lengths from lettuce and cucumber seeds grown in the remediated soils confirmed that the soil quality improved after bioremediation. This study clearly demonstrates the potential of Hg-reducing bacteria in remediation of Hg-contaminated soils. However, it is desirable to trap the volatilized Hg for enhanced bioremediation. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface-flow constructed wetlands dominated by Cladophora for reclaiming nutrients in diffuse domestic effluent.

PubMed

Zhu, Huaqing; Lu, Xiwu; Dai, Hongliang

2018-03-01

In this work, a surface-flow constructed wetland (SFCW) dominated by Cladophora was used to remove and reclaim nutrients in diffuse domestic effluent (DDE) discharged from rural regions around Taihu Lake, a eutrophic shallow lake in China. Growth rate of Cladophora was investigated and linked to ambient factors and nutrient consuming rates. The growth performances of Cladophora and animal-feed microbes were studied during the commissioning of SFCW. Results show that the growth rate of Cladophora was closely correlated with field temperature and surface irradiance, while surface coverage was suitable for the manipulation of SFCW. Harvest of Cladophora along with animal-feed microbes and removal of nutrients in DDE could be achieved by manipulating surface coverage to drag growth rate back at the end of linear zone and to quickly restore Cladophora biomass in the mid zone of surface growth rate. Among four stages of the commissioning, concentrating stage experienced the majority species of animal-feed microbes and maximal nutrient removal; during decomposing stage, however, the reproduction of animal-feed microbes and nutrient removal were lower, whereas the density of pathogens was higher. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using agro-industrial wastes for the cultivation of microalgae and duckweeds: Contamination risks and biomass safety concerns.

PubMed

Markou, Giorgos; Wang, Liang; Ye, Jianfeng; Unc, Adrian

Aquatic organisms, such as microalgae (Chlorella, Arthrospira (Spirulina), Tetrasselmis, Dunalliela etc.) and duckweed (Lemna spp., Wolffia spp. etc.) are a potential source for the production of protein-rich biomass and for numerous other high-value compounds (fatty acids, pigments, vitamins etc.). Their cultivation using agro-industrial wastes and wastewater (WaW) is of particular interest in the context of a circular economy, not only for recycling valuable nutrients but also for reducing the requirements for fresh water for the production of biomass. Recovery and recycling of nutrients is an unavoidable long-term approach for securing future food and feed production. Agro-industrial WaW are rich in nutrients and have been widely considered as a potential nutrient source for the cultivation of microalgae/duckweed. However, they commonly contain various hazardous contaminants, which could potentially taint the produced biomass, raising various concerns about the safety of their consumption. Herein, an overview of the most important contaminants, including heavy metals and metalloids, pathogens (bacteria, viruses, parasites etc.), and xenobiotics (hormones, antibiotics, parasiticides etc.) is given. It is concluded that pretreatment and processing of WaW is a requisite step for the removal of several contaminants. Among the various technologies, anaerobic digestion (AD) is widely used in practice and offers a technologically mature approach for WaW treatment. During AD, various organic and biological contaminants are significantly removed. Further removal of contaminants could be achieved by post-treatment and processing of digestates (solid/liquid separation, dilution etc.) to further decrease the concentration of contaminants. Moreover, during cultivation an additional removal may occur through various mechanisms, such as precipitation, degradation, and biotransformation. Since many jurisdictions regulate the presence of various contaminants in feed or food setting strict safety monitoring processes, it would be of particular interest to initiate a multi-disciplinary discussion whether agro-industrial WaW ought to be used to cultivate microalgae/duckweed for feed or food production and identify most feasible options for doing this safely. Based on the current body of knowledge it is estimated that AD and post-treatment of WaW can lower significantly the risks associated with heavy metals and pathogens, but it is yet unclear to what extent this is the case for certain persistent xenobiotics. Copyright © 2018 Elsevier Inc. All rights reserved.

Simultaneous biological nutrient removal: evaluation of autotrophic denitrification, heterotrophic nitrification, and biological phosphorus removal in full-scale systems.

PubMed

Littleton, Helen X; Daigger, Glen T; Strom, Peter F; Cowan, Robert A

2003-01-01

Simultaneous biological nutrient removal (SBNR) is the biological removal of nitrogen and phosphorus in excess of that required for biomass synthesis in a biological wastewater treatment system without defined anaerobic or anoxic zones. Evidence is growing that significant SBNR can occur in many systems, including the aerobic zone of systems already configured for biological nutrient removal. Although SBNR systems offer several potential advantages, they cannot be fully realized until the mechanisms responsible for SBNR are better understood. Consequently, a research program was initiated with the basic hypothesis that three mechanisms might be responsible for SBNR: the reactor macroenvironment, the floc microenvironment, and novel microorganisms. Previously, the nutrient removal capabilities of seven full-scale, staged, closed-loop bioreactors known as Orbal oxidation ditches were evaluated. Chemical analysis and microbiological observations suggested that SBNR occurred in these systems. Three of these plants were further examined in this research to evaluate the importance of novel microorganisms, especially for nitrogen removal. A screening tool was developed to determine the relative significance of the activities of microorganisms capable of autotrophic denitrification and heterotrophic nitrification-aerobic denitrification in biological nutrient removal systems. The results indicated that novel microorganisms were not substantial contributors to SBNR in the plants studied. Phosphorus metabolism (anaerobic release, aerobic uptake) was also tested in one of the plants. Activity within the mixed liquor that was consistent with current theories for phosphorus-accumulating organisms (PAOs) was observed. Along with other observations, this suggests the presence of PAOs in the facilities studied.

Evaluation of nutrients removal (NO3-N, NH3-N and PO4-P) with Chlorella vulgaris, Pseudomonas putida, Bacillus cereus and a consortium of these microorganisms in the treatment of wastewater effluents.

PubMed

Gómez-Guzmán, Abril; Jiménez-Magaña, Sergio; Guerra-Rentería, A Suggey; Gómez-Hermosillo, César; Parra-Rodríguez, F Javier; Velázquez, Sergio; Aguilar-Uscanga, Blanca Rosa; Solis-Pacheco, Josue; González-Reynoso, Orfil

2017-07-01

In this research removal of NH 3 -N, NO 3 -N and PO 4 -P nutrients from municipal wastewater was studied, using Chlorella vulgaris, Pseudomonas putida, Bacillus cereus and an artificial consortium of them. The objective is to analyze the performance of these microorganisms and their consortium, which has not been previously studied for nutrient removal in municipal wastewater. A model wastewater was prepared simulating the physicochemical characteristics found at the wastewater plant in Chapala, Mexico. Experiments were carried out without adding an external carbon source. Results indicate that nutrient removal with Chlorella vulgaris was the most efficient with a removal of 24.03% of NO 3 -N, 80.62% of NH 3 -N and 4.30% of PO 4 -P. With Bacillus cereus the results were 8.40% of NO 3 -N, 28.80% of NH 3 -N and 3.80% of PO 4 -P. The removals with Pseudomonas putida were 2.50% of NO 3 -N, 41.80 of NH 3 -N and 4.30% of PO 4 -P. The consortium of Chlorella vulgaris-Bacillus cereus-Pseudomonas putida removed 29.40% of NO 3 -N, 4.2% of NH 3 -N and 8.4% of PO 4 -P. The highest biomass production was with Bacillus cereus (450 mg/l) followed by Pseudomonas putida (444 mg/l), the consortium (205 mg/l) and Chlorella vulgaris (88.9 mg/l). This study highlights the utility of these microorganisms for nutrient removal in wastewater treatments.

Semi-solid state bioremediation of CCA-treated wood using malted barley as a nutrient source

Treesearch

Carol A. Clausen

2002-01-01

Bioremediation processes for recovery and reuse of CCA-treated wood invariably increase the cost of any secondary products manufactured from the remediated fiber. Microbial remediation using either bacteria or fungi has been shown to remove heavy metals from CCA-treated southern yellow pine (SYP). In a two-step remediation process utilizing oxalic acid extraction and...

Reliability analysis of nutrient removal from stormwater runoff with green sorption media under varying influent conditions.

PubMed

Jones, Jamie; Chang, Ni-Bin; Wanielista, Martin P

2015-01-01

To support nutrient removal, various stormwater treatment technologies have been developed via the use of green materials, such as sawdust, tire crumbs, sand, clay, sulfur, and limestone, as typical constituents of filter media mixes. These materials aid in the physiochemical sorption and precipitation of orthophosphates as well as in the biological transformation of ammonia, nitrates and nitrites. However, these processes are dependent upon influent conditions such as hydraulic residence time, influent orthophosphate concentrations, and other chemical species present in the inflow. This study aims to compare the physiochemical removal of orthophosphate by isotherm and column tests under differing influent conditions to realize the reliability of orthophosphate removal process with the aid of green sorption media. The green sorption media of interest in this study is composed of a 5:2:2:1 (by volume) mixture of cement sand, tire crumb, fine expanded clay, and limestone. Scenarios of manipulating the hydraulic residence time of the water from 18 min and 60 min, the influent dissolved phosphorus concentrations of 1.0 mg·L(-1) and 0.5 mg·L(-1), and influent water types of distilled and pond water, were all investigated in the column tests. Experimental data were compared with the outputs from the Thomas Model based on orthophosphate removal to shed light on the equilibrium condition versus kinetic situation. With ANOVA tests, significant differences were confirmed between the experimental data sets of the breakthrough curves in the column tests. SEM imaging analysis helps to deepen the understanding of pore structures and pore networks of meta-materials being used in the green sorption media. Life expectancy curves derived from the output of Thomas Model may be applicable for future system design of engineering processes. Copyright © 2014 Elsevier B.V. All rights reserved.

The role of sulfate in aerobic granular sludge process for emerging sulfate-laden wastewater treatment.

PubMed

Xue, Weiqi; Hao, Tianwei; Mackey, Hamish R; Li, Xiling; Chan, Richard C; Chen, Guanghao

2017-11-01

Sulfate-rich wastewaters pose a major threat to mainstream wastewater treatment due to the unpreventable production of sulfide and associated shift in functional bacteria. Aerobic granular sludge could mitigate these challenges in view of its high tolerance and resilience against changes in various environmental conditions. This study aims to confirm the feasibility of aerobic granular sludge in the treatment of sulfate containing wastewater, investigate the impact of sulfate on nutrient removal and granulation, and reveal metabolic relationships in the above processes. Experiments were conducted using five sequencing batch reactors with different sulfate concentrations operated under alternating anoxic/aerobic condition. Results showed that effect of sulfate on chemical oxygen demand (COD) removal is negligible, while phosphate removal was enhanced from 12% to 87% with an increase in sulfate from 0 to 200 mg/L. However, a long acclimatization of the biomass (more than 70 days) is needed at a sulfate concentration of 500 mg/L and a total deterioration of phosphate removal at 1000 mg/L. Batch tests revealed that sulfide promoted volatile fatty acids (VFAs) uptake, producing more energy for phosphate uptake when sulfate concentrations were beneath 200 mg/L. However, sulfide detoxification became energy dominating, leaving insufficient energy for Polyhydroxyalkanoate (PHA) synthesis and phosphate uptake when sulfate content was further increased. Granulation accelerated with increasing sulfate levels by enhanced production of N-Acyl homoserine lactones (AHLs), a kind of quorum sensing (QS) auto-inducer, using S-Adenosyl Methionine (SAM) as primer. The current study demonstrates interactions among sulfate metabolism, nutrients removal and granulation, and confirms the feasibility of using the aerobic granular sludge process for sulfate-laden wastewaters treatment with low to medium sulfate content. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sustainable Landscape Systems for Managing Storm Water 2nd Edition

EPA Science Inventory

Rain gardens are designed to capture and infiltrate rainwater in the landscape. These gardens are also called "rain water gardens". Rainwater is routed to the garden and filtered naturally by the plants and soils in the garden. This filtration process removes nutrients and poll...

Nutrient removal by up-scaling a hybrid floating treatment bed (HFTB) using plant and periphyton: From laboratory tank to polluted river.

PubMed

Liu, Junzhuo; Wang, Fengwu; Liu, Wei; Tang, Cilai; Wu, Chenxi; Wu, Yonghong

2016-05-01

Planted floating treatment bed (FTB) is an innovative technique of removing nutrients from polluted water but limited in deep water and cold seasons. Periphyton was integrated into FTB for a hybrid floating treatment bed (HFTB) to improve its nutrient removal capacity. To assess its potential for treating nutrient-polluted rivers, HFTB was up-scaled from 5L laboratory tanks to 350L outdoor tanks and then to a commercial-scale 900m section of polluted river. Plants and periphyton interacted in HFTB with periphyton limiting plant root growth and plants having shading effects on periphyton. Non-overlapping distribution of plants and periphyton can minimize the negative interactions in HFTB. HFTB successfully kept TN and TP of the river at less than 2.0 and 0.02mgL(-1), respectively. This study indicates that HFTB can be easily up-scaled for nutrients removal from polluted rivers in different seasons providing a long-term, environmentally-friendly method to remediate polluted ecosystems. Copyright © 2016 Elsevier Ltd. All rights reserved.

Energy efficient reconcentration of diluted human urine using ion exchange membranes in bioelectrochemical systems.

PubMed

Tice, Ryan C; Kim, Younggy

2014-11-01

Nutrients can be recovered from source separated human urine; however, nutrient reconcentration (i.e., volume reduction of collected urine) requires energy-intensive treatment processes, making it practically difficult to utilize human urine. In this study, energy-efficient nutrient reconcentration was demonstrated using ion exchange membranes (IEMs) in a microbial electrolysis cell (MEC) where substrate oxidation at the MEC anode provides energy for the separation of nutrient ions (e.g., NH4(+), HPO4(2-)). The rate of nutrient separation was magnified with increasing number of IEM pairs and electric voltage application (Eap). Ammonia and phosphate were reconcentrated from diluted human urine by a factor of up to 4.5 and 3.0, respectively (Eap = 1.2 V; 3-IEM pairs). The concentrating factor increased with increasing degrees of volume reduction, but it remained stationary when the volume ratio between the diluate (urine solution that is diluted in the IEM stack) and concentrate (urine solution that is reconcentrated) was 6 or greater. The energy requirement normalized by the mass of nutrient reconcentrated was 6.48 MJ/kg-N (1.80 kWh/kg-N) and 117.6 MJ/kg-P (32.7 kWh/kg-P). In addition to nutrient separation, the examined MEC reactor with three IEM pairs showed 54% removal of COD (chemical oxygen demand) in 47-hr batch operation. The high sulfate concentration in human urine resulted in substantial growth of both of acetate-oxidizing and H2-oxidizing sulfate reducing bacteria, greatly diminishing the energy recovery and Coulombic efficiency. However, the high microbial activity of sulfate reducing bacteria hardly affected the rate of nutrient reconcentration. With the capability to reconcentrate nutrients at a minimal energy consumption and simultaneous COD removal, the examined bioelectrochemical treatment method with an IEM application has a potential for practical nutrient recovery and sustainable treatment of source-separated human urine. Copyright © 2014 Elsevier Ltd. All rights reserved.

Removal of Nutrients from Septic Effluent with Re-circulated Hybrid Tidal Flow Constructed Wetland

Treesearch

Lihua Cui; Jigkun Feng; Ying Ouyang; Peiwen Deng

2012-01-01

Hybrid tidal flow constructed wetland (CW) with recirculation is an improved biological and engineering technique for removal of excess nutrients and certain pollutants from wastewater. This study investigated the removal efficiency of total phosphorus (TP), ammonia-nitrogen (NH3-N), and total nitrogen (TN) from septic tank effluent with the hybrid tidal flow CW system...

Adsorption of mixtures of nutrients and heavy metals in simulated urban stormwater by different filter materials.

PubMed

Reddy, Krishna R; Xie, Tao; Dastgheibi, Sara

2014-01-01

In recent years, several best management practices have been developed for the removal of different types of pollutants from stormwater runoff that lead to effective stormwater management. Filter materials that remove a wide range of contaminants have great potential for extensive use in filtration systems. In this study, four filter materials (calcite, zeolite, sand, and iron filings) were investigated for their adsorption and efficiency in the removal of nutrients and heavy metals when they exist individually versus when they co-exist. Laboratory batch experiments were conducted separately under individual and mixed contaminants conditions at different initial concentrations. Adsorption capacities varied under the individual and mixed contaminant conditions due to different removal mechanisms. Most filter materials showed lower removal efficiency under mixed contaminant conditions. In general, iron filings were found effective in the removal of nutrients and heavy metals simultaneously to the maximum levels. Freundlich and Langmuir isotherms were used to model the batch adsorption results and the former better fitted the experimental results. Overall, the results indicate that the filter materials used in this study have the potential to be effective media for the treatment of nutrients and heavy metals commonly found in urban stormwater runoff.

Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin

USGS Publications Warehouse

O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G.

2012-01-01

Soil beneath a stormwater infiltration basin receiving runoff from a 22.7 ha predominantly residential watershed in central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop a prototype stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO3-/Cl-) ratios for the shallow groundwater indicate that prior to using BAM, NO3- concentrations were substantially influenced by nitrification or variations in NO3- input. In contrast, for the prototype basin utilizing BAM, NO3-/Cl- ratios indicate minor nitrification and NO3- losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest NO3- losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO43-) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO43-/Cl- ratios for shallow groundwater indicate predominantly minor increases and decreases in PO43- with the exception of one summer sample that indicated a 50% loss. Differences in nutrient variations between the unsaturated zone and shallow groundwater may be the result of the intensity and duration of nutrient removal processes and mixing ratios with water that had not undergone significant chemical changes. Observed nitrogen and phosphorus losses demonstrate the potential, as well as future research needs to improve performance, of the prototype stormwater infiltration basin using BAM for providing passive, economical, stormwater nutrient-treatment technology to support green infrastructure.

Up-to-date modification of the anaerobic sludge digestion process introducing a separate sludge digestion mode.

PubMed

Sato, K; Ochi, S; Mizuochi, M

2001-01-01

Sewage treatment plants in Japan are subjected to advanced treatment to remove nutrients and hence control eutrophication problems in lakes and bays. This paper discusses the advantages and disadvantages of the separate digestion treatment mode for sludge generated from advanced wastewater treatment. In the separate digestion only primary sludge is digested and the excess activated sludge is directly dewatered. Separate digestion can reduce the return load of nutrients to approximately one third, and has major potential for the beneficial use of sludge.

Role of algal biofilm in improving the performance of free surface, up-flow constructed wetland.

PubMed

Badhe, Neha; Saha, Shaswati; Biswas, Rima; Nandy, Tapas

2014-10-01

The role of algal biofilm in a pilot-scale, free-surface, up-flow constructed wetland (CW), was studied for its effect on chemical oxygen demand (COD), ammonia and phosphate removal during three seasons-autumn, winter and early spring. Effect of hydraulic retention time (HRT) was also investigated in presence and absence of algal biofilm. Principal Component Analysis was used to identify the independent factors governing the performance of CW. The study showed algal biofilm significantly improved nutrient removal, especially phosphate. Ammonia removal varied with HRT, biofilm and ambient temperature. Increase in biofilm thickness affected ammonia removal efficiency adversely. Algal biofilm-assisted COD removal compensated for reduced macrophyte density during winter. Two-way ANOVA test and the coefficients of dependent factors derived through multiple linear regression model confirmed role of algal biofilm in improving nutrient removal in CW. The study suggests that algal biofilm can be a green solution for bio-augmenting COD and nutrient removal in CW. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pollutant removal characteristics of a two-influent-line BNR process performing denitrifying phosphorus removal: role of sludge recycling ratios.

PubMed

Liu, Hongbo; Leng, Feng; Chen, Piao; Kueppers, Stephan

2016-11-01

This paper studied denitrifying phosphorus removal of a novel two-line biological nutrient removal process treating low strength domestic wastewater under different sludge recycling ratios. Mass balance of intracellular compounds including polyhydroxyvalerate, polyhydroxybutyrate and glycogen was investigated together with total nitrogen (TN) and total phosphorus (TP). Results showed that sludge recycling ratios had a significant influence on the use of organics along bioreactors and 73.6% of the average removal efficiency was obtained when the influent chemical oxygen demand (COD) ranged from 175.9 mgL -1 to 189.9 mgL -1 . The process performed better under a sludge recycling ratio of 100% compared to 25% and 50% in terms of ammonia and COD removal rates. Overall, TN removal efficiency for 50% and 100% sludge recycling ratios were 56.4% and 61.9%, respectively, unlike the big gap for carbon utilization and the TP removal rates, indicating that the effect of sludge recycling ratio on the anaerobic compartments had been counteracted by change in the efficiency of other compartments. The higher ratio of sludge recycling was conducive to the removal of TN, not in favor of TP, and less influence on COD. Thus, 25% was considered to be the optimal sludge recycling ratio.

Nutrient sampling slam: high resolution surface-water sampling in streams reveals patterns in groundwater chemistry and flow paths

EPA Science Inventory

The groundwater–surface water interface (GSWI), consisting of shallow groundwater adjacent to stream channels, is a hot spot for nitrogen removal processes, a storage zone for other solutes, and a target for restoration activities. Characterizing groundwater-surface water intera...

Phosphorus recovery from anaerobic swine lagoon sludge using the quick wash process

USDA-ARS?s Scientific Manuscript database

Long term accumulation of sludge in anaerobic swine lagoons reduces its storage volume and ability to treat waste. Usually, excess accumulation of lagoon sludge is removed using pumping dredges. The dredged sludge is then land applied at agronomic rates according to its nutrient content. The accumul...

Phosphorus recovery from anaerobic swine lagoon sludge using the quick wash process

USDA-ARS?s Scientific Manuscript database

Long term and significant accumulation of sludge in anaerobic swine lagoons reduces its storage volume and ability to treat waste. Usually, excess accumulation of lagoon sludge is removed by dredging. The dredged sludge is then land applied at agronomic rates according to its nutrient content. Becau...

Biofiltration of air contaminated by styrene: Effect of nitrogen supply, gas flow rate, and inlet concentration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jorio, H.; Bibeau, L.; Heitz, M.

2000-05-01

The biofiltration process is a promising technology for the treatment of dilute styrene emissions in air. The efficiency of this process is however strongly dependent upon various operational parameters such as the filter bed characteristics, nutrient supplies, input contaminant concentrations, and gas flow rates. The biofiltration of air containing styrene vapors was therefore investigated, employing a novel biomass filter material, in two identical but separate laboratory scale biofiltration units (units 1 and 2), both biofilters being initially inoculated with a microbial consortium. Each biofilter was irrigated with a nutrient solution supplying nitrogen in one of two forms; i.e., mainly asmore » ammonia for unit 1 and exclusively as nitrate for unit 2. The experimental results have revealed that greater styrene elimination rates are achieved in the biofilter supplied with ammonia as the major nitrogen source in comparison to the lesser elimination performance obtained with the nitrate provided biofilter. However, in achieving the high styrene removal rates in the ammonia supplied biofilter, the excess of biomass accumulates on the filtering pellets and causes progressive clogging of the filter media. Furthermore, the effectiveness of nitrate supply as the sole nitrogen nutrient form, on reducing or controlling the biomass accumulation in the filter media in comparison to ammonia, could not be satisfactorily demonstrated because the two biofilters operated with very different styrene elimination capacities. The monitoring of the carbon dioxide concentration profile through both biofilters revealed that the ratio of carbon dioxide produced to the styrene removed was approximately 3/1, which confirms the complete biodegradation of removed styrene, given that some of the organic carbon consumed is also used for the microbial growth. The effects of the most important design parameters, namely styrene input concentrations and gas flow rates, were investigated for each nutrient solution.« less

Dynamic control of nutrient-removal from industrial wastewater in a sequencing batch reactor, using common and low-cost online sensors.

PubMed

Dries, Jan

2016-01-01

On-line control of the biological treatment process is an innovative tool to cope with variable concentrations of chemical oxygen demand and nutrients in industrial wastewater. In the present study we implemented a simple dynamic control strategy for nutrient-removal in a sequencing batch reactor (SBR) treating variable tank truck cleaning wastewater. The control system was based on derived signals from two low-cost and robust sensors that are very common in activated sludge plants, i.e. oxidation reduction potential (ORP) and dissolved oxygen. The amount of wastewater fed during anoxic filling phases, and the number of filling phases in the SBR cycle, were determined by the appearance of the 'nitrate knee' in the profile of the ORP. The phase length of the subsequent aerobic phases was controlled by the oxygen uptake rate measured online in the reactor. As a result, the sludge loading rate (F/M ratio), the volume exchange rate and the SBR cycle length adapted dynamically to the activity of the activated sludge and the actual characteristics of the wastewater, without affecting the final effluent quality.

Biochar from Pyrolysis of Biosolids for Nutrient Adsorption and Turfgrass Cultivation.

PubMed

Carey, D E; McNamara, P J; Zitomer, D H

2015-12-01

At water resource recovery facilities, nutrient removal is often required and energy recovery is an ever-increasing goal. Pyrolysis may be a sustainable process for handling wastewater biosolids because energy can be recovered in the py-gas and py-oil. Additionally, the biochar produced has value as a soil conditioner. The objective of this work was to determine if biochar could be used to adsorb ammonia from biosolids filtrate and subsequently be applied as a soil conditioner to improve grass growth. The maximum carrying capacity of base modified biochar for NH3-N was 5.3 mg/g. Biochar containing adsorbed ammonium and potassium was applied to laboratory planters simulating golf course putting greens to cultivate Kentucky bluegrass. Planters that contained nutrient-laden biochar proliferated at a statistically higher rate than planters that contained biosolids, unmodified biochar, peat, or no additive. Nutrient-laden biochar performed as well as commercial inorganic fertilizer with no statistical difference in growth rates. Biochar from digested biosolids successfully immobilized NH3-N from wastewater and served as a beneficial soil amendment. This process offers a means to recover and recycle nutrients from water resource recovery facilities.

Anaerobes, aerobes and phototrophs. A winning team for wastewater management.

PubMed

Gijzen, H J

2001-01-01

Current mainstream technologies for wastewater treatment, such as activated sludge and tertiary nutrient removal, are too costly to provide a satisfactory solution for the increasing wastewater problems in developing regions. Besides, these technologies do not allow for re-use of valuable energy and nutrients contained in the wastewater. In light of these limitations, it is important to reconsider the technology and strategic approaches in wastewater management. This paper introduces the "Cleaner Production" concept to sewage management, which combines two approaches: pollution prevention and re-use. Pollution prevention includes a shift towards low water use sanitation technology. The more concentrated wastewater, becomes more attractive for re-use oriented treatment schemes. A combination of anaerobic pre-treatment followed by macrophyte-covered stabilisation ponds is proposed for the effective recovery of energy and nutrients from sewage. By selecting optimal applications of the plant biomass and pond effluent, nutrients will end up as fish and crop protein. This contrasts favourably to tertiary nitrogen removal in activated sludge systems, which recycles ammonia through molecular nitrogen at the expense of energy and high costs. Macrophyte ponds are proposed as a key step in waste recycling, because these form the central unit of a recycling engine, driven by photosynthesis. The process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions.

Spatially variable synergistic effects of disturbance and additional nutrients on kelp recruitment and recovery.

PubMed

Carnell, Paul E; Keough, Michael J

2014-05-01

Understanding the impact of multiple stressors on ecosystems is of pronounced importance, particularly when one or more of those stressors is anthropogenic. Here we investigated the role of physical disturbance and increased nutrients on reefs dominated by the canopy-forming kelp Ecklonia radiata. We combined experimental kelp canopy removals and additional nutrient at three different locations in a large embayment in temperate southeastern Australia. Over the following winter recruitment season, Ecklonia recruitment was unaffected by increased nutrients alone, but tripled at all sites where the canopy had been removed. At one site, the combination of disturbance and increased nutrients resulted in more than four times the recruitment of the introduced kelp Undaria pinnatifida. Six months after disturbance, the proliferation of the Undaria canopy in the canopy-removal and nutrient-addition treatment negatively influenced the recovery of the native kelp Ecklonia. Given the otherwise competitive dominance of adult Ecklonia, this provides a mechanism whereby Undaria could maintain open space for the following recruitment season. This interplay between disturbance, nutrients and the response of native and invasive species makes a compelling case for how a combination of factors can influence species dynamics.

Long-Term Nutrient Performance in a Bioinfiltration Rain Garden

EPA Science Inventory

The goals of this study is to gain a better understanding of the nutrients and metals removal mechanisms involved in a bioinfiltration stormwater abatement system, predict the useful life of a bioinfiltration BMP for the removal of certain contaminants and assess toxicity of stor...

Green microalga Scenedesmus acutus grown on municipal wastewater to couple nutrient removal with lipid accumulation for biodiesel production.

PubMed

Sacristán de Alva, Manuel; Luna-Pabello, Víctor M; Cadena, Erasmo; Ortíz, Edgar

2013-10-01

The green microalga Scenedesmus acutus was cultivated in two different municipal wastewater discharges (pre- and post-treated), and was compared to a culture medium with basic nutrients (20% of N, P, K), in order to study the simultaneous potential of nutrient removal and lipid accumulation ability. The highest level of nutrient removal was found in the pretreated wastewater discharge (achieving a high removal of phosphorus [66%] and organic nitrogen [94%]). Likewise, better results on biomass productivity and lipid accumulation were found in cultures using pretreated wastewater compared to enriched medium, obtaining 79.9 mg/L, and 280 mg/L, respectively. Since the best results were found in pretreated wastewater, the biodiesel preparation was performed using said medium at small-scale. After cultivation, 249.4 mg/L of biodiesel were obtained. According to this analysis, S. acutus could be used for wastewater treatment producing biomass with a suitable content of lipids, convenient for biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Verhulst model for microalgae Botryococcus sp. growth and nutrient removal in wastewater

NASA Astrophysics Data System (ADS)

Jamaian, Siti Suhana; Bakeri, Noorhadila Mohd; Sunar, Norshuhaila Mohamed; Gani, Paran

2017-08-01

Microalgae Botryococcus sp. is a colonial green alga found in lakes and reservoirs in Malaysia. Previous studies reported that the potential of Botryococcus sp. photosynthesis as a source of fuel. The Botryococcus sp. contains hydrocarbon up to 75% of dry weight, which can be converted into petrol, diesel or turbine fuel or other liquid or gaseous hydrocarbons. Recently, an experimental study was conducted on phycoremediation technology for wastewater using Botryococcus sp. The phycoremediation technology is useful to remove the excess of nutrients such as nitrogen, phosphorus and also have the ability to remove various pollutants from wastewater. This research implements the Verhulst model to estimate the nutrient removal by microalgae Botryococcus sp. from the wastewater. This model has been validated with the experiments of microalgae Botryococcus sp. grown in domestic and palm oil wastewater. The results suggested that microalgae Botryococcus sp. could be cultured in domestic and palm oil wastewater while nutrients are reduced from these wastewaters.

Investigation of the effects of slow-release fertilizer and struvite in biodegradation in filter drains and potential application of treated water in irrigation of road verges.

PubMed

Theophilus, Stephen C; Mbanaso, Fredrick U; Nnadi, Ernest O; Onyedeke, Kingsley T

2017-11-14

Filter drains are usually laid along the margins of highways. Highway runoffs are polluted with hydrocarbons and high levels of total dissolved solids. Therefore, effective pollution removal mechanism is necessary in order to avoid contamination of surrounding soils and groundwater. Biodegradation is amongst pollution removal mechanisms in filter drains, but it is a relatively slow process which is dependent on wide range of factors including the type of pollutant and availability of nutrients. This paper reports on a study conducted to investigate the impact of slow-release fertilizer and struvite in enhancement of biodegradation of hydrocarbon in filter drains. Filter drain models incorporated with geotextile were challenged with cumulative oil loading of 178 mg/m 2 /week with a view to comparing the efficiency of these two nutrient sources under high oil pollution loading and realistic rainfall conditions of 13 mm/week. Nutrients and street dust were applied at one-off rate of 17 g/m 2 and 1.55 g/rig to provide nutrient enhancement and simulate field conditions respectively. The impact of the nutrients was studied by monitoring bacterial and fungal growth using nutrient agar, Rose Bengal Agar media and CO2 evolution. EC, pH, heavy metals, TPH, elemental analysis and SAR were used to investigate water quality of effluent of filter drains for potential application as irrigation fluid for trees and flowers planted on road verges. The results show that nutrient application encouraged microbial activities and enhanced biodegradation rates with differences in type of nutrient applied. Also, it was observed that incorporation of geotextiles in filter drains improved pollution retention efficiency and there is a potential opportunity for utilization of struvite in SuDS systems as sustainable nutrient source.

Comparison between disintegrated and fermented sewage sludge for production of a carbon source suitable for biological nutrient removal.

PubMed

Soares, Ana; Kampas, Pantelis; Maillard, Sarah; Wood, Elizabeth; Brigg, Jon; Tillotson, Martin; Parsons, Simon A; Cartmell, Elise

2010-03-15

There is a need to investigate processes that enable sludge re-use while enhancing sewage treatment efficiency. Mechanically disintegrated thickened surplus activated sludge (SAS) and fermented primary sludge were compared for their capacity to produce a carbon source suitable for BNR by completing nutrient removal predictive tests. Mechanically disintegration of SAS using a deflaker enhanced volatile fatty acids (VFAs) content from 92 to 374 mg l(-1) (4.1-fold increase). In comparison, primary sludge fermentation increased the VFAs content from 3.5 g l(-1) to a final concentration of 8.7 g l(-1) (2.5-fold increase). The carbon source obtained from disintegration and fermentation treatments improved phosphate (PO(4)-P) release and denitrification by up to 0.04 mg NO(3)-Ng(-1)VSS min(-1) and 0.031 mg PO(4)-Pg(-1)VSS min(-1), respectively, in comparison to acetate (0.023 mg NO(3)-Ng(-1)VSS min(-1)and 0.010 mg PO(4)-Pg(-1)VSS min(-1)). Overall, both types of sludge were suitable for BNR but disintegrated SAS displayed lower carbon to nutrient ratios of 8 for SCOD:PO(4)-P and 9 for SCOD:NO(3)-N. On the other hand, SAS increased the concentration of PO(4)-P in the settled sewage by a further 0.97 g PO(4)-P kg(-1)SCOD indicating its potential negative impact towards nutrient recycling in the BNR process. (c) 2009 Elsevier B.V. All rights reserved.

Soil nutrient availability and reproductive effort drive patterns in nutrient resorption in Pentachlethra macroloba

Treesearch

K. L. Tully; Tana Wood; A. M. Schwantes; D. Lawrence

2013-01-01

The removal of nutrients from senescing tissues, nutrient resorption, is a key strategy for conserving nutrients in plants. However, our understanding of what drives patterns of nutrient resorption in tropical trees is limited. We examined the effects of nutrient sources (stand-level and tree-level soil fertility) and sinks (reproductive effort) on nitrogen (N) and...

Optimisation of Noosa BNR plant to improve performance and reduce operating costs.

PubMed

Thomas, M; Wright, P; Blackall, L; Urbain, V; Keller, J

2003-01-01

Noosa WWTP is publicly owned and privately operated by Australian Water Services. The process includes primary sedimentation, raw sludge fermentation, biological nutrient removal (BNR), sand filtration and ultraviolet (UV) disinfection. An innovative feature of the plant is the supplementary carbon dosing facility to avoid the use of metal salts (alum or ferric) for phosphorus removal. The average flow treated during 2000 was 9.0 ML/d. The annual 50 percentile effluent quality requirements for nutrients are total N < 5 mg/L and total P < 1 mg/L. The objectives of this project were to: determine the cause of variability in phosphorus removal; develop a strategy to control the variability in phosphorus removal; and minimise the operating cost of supplementary carbon dosing while achieving the effluent quality requirements. An investigation of chemical and microbiological parameters was implemented and it was concluded that there were several factors causing variability in phosphorus removal, rather than a single cause. The following four major causes were identified, and the control strategies that were adopted resulted in the plant achieving annual 50 percentile effluent total P = 0.37 mg/L and total N = 3.0 mg/L during 2001. First, phosphorus removal was limited by the available VFA supply due to consumption of VFA by other organisms competing with phosphate accumulating organisms (PAO), and due to diurnal variations in the sewage VFA and phosphate concentrations. Therefore, supplementary carbon dosing was essential to make allowance for competing reactions. Second, increasing the fermenter VFA yield via supplementary carbon dosing with molasses was found to be an effective and economic way of ensuring reliable phosphorus removal. Third, nitrate in the RAS resulted in consumption of VFA by denitrifying bacteria, particularly with process configurations where the RAS was recycled directly into the anaerobic zone. Incorporating a RAS denitrification zone into the process rectified this problem. Finally, glycogen accumulating organisms (GAO) were observed in BNR sludge samples, and consumption of VFA by GAO appeared to cause decreased phosphorus removal. Better phosphorus removal was obtained using VFA derived from the fermenter than dosing an equivalent amount of acetic acid. It was hypothesized that GAO have a competitive advantage to use acetate and PAO have a competitive advantage to use propionate, butyrate or some other soluble COD compound in the fermenter effluent. Contrary to popular belief, acetate may not be the optimum VFA for biological phosphorus removal. The competition between PAO and GAO for different VFA species under anaerobic conditions requires further investigation in order to control the growth of GAO and thereby improve reliability of biological phosphorus removal processes.

The rapid return of marine-derived nutrients to a freshwater food web following dam removal

USGS Publications Warehouse

Tonra, Christopher M; Sager-Fradkin, Kimberly A.; Morley, Sarah A; Duda, Jeff; Marra, Peter P.

2015-01-01

Dam removal is increasingly being recognized as a viable river restoration action. Although the main beneficiaries of restored connectivity are often migratory fish populations, little is known regarding recovery of other parts of the freshwater food web, particularly terrestrial components. We measured stable isotopes in key components to the freshwater food web: salmon, freshwater macroinvertebrates and a river specialist bird, American dipper (Cinclus mexicanus), before and after removal of the Elwha Dam, WA, USA. Less than a year after dam removal, salmon returned to the system and released marine-derived nutrients (MDN). In that same year we documented an increase in stable-nitrogen and carbon isotope ratios in American dippers. These results indicate that MDN from anadromous fish, an important nutrient subsidy that crosses the aquatic–terrestrial boundary, can return rapidly to food webs after dams are removed which is an important component of ecosystem recovery.

Fed-batch cultivation of Arthrospira and Chlorella in ammonia-rich wastewater: Optimization of nutrient removal and biomass production.

PubMed

Markou, Giorgos

2015-10-01

In the present work the cyanobacterium Arthrospira platensis and the microalga Chlorella vulgaris were fed-batch cultivated in ammonia-rich wastewater derived from the anaerobic digestion of poultry litter. Aim of the study was to maximize the biomass production along with the nutrient removal aiming to wastewater treatment. Ammonia and phosphorus removals were very high (>95%) for all cultures investigated. Both microorganisms were able to remove volatile fatty acids to an extent of >90%, indicating that they were capable of mixotrophic growth. Chemical oxygen demand and proteins were also removed in various degrees. In contrast, in all cultures carbohydrate concentration was increased. The biochemical composition of the microorganisms varied greatly and was influenced by the indicate that the nutrient availability. A. platensis accumulated carbohydrates (≈ 40%), while C. vulgaris accumulated lipids (≈ 50%), rendering them interesting for biofuel production. Copyright © 2015 Elsevier Ltd. All rights reserved.

Agricultural conservation planning framework: 1. Developing multipractice watershed planning scenarios and assessing nutrient reduction potential.

PubMed

Tomer, M D; Porter, S A; Boomer, K M B; James, D E; Kostel, J A; Helmers, M J; Isenhart, T M; McLellan, E

2015-05-01

Spatial data on soils, land use, and topography, combined with knowledge of conservation effectiveness, can be used to identify alternatives to reduce nutrient discharge from small (hydrologic unit code [HUC]12) watersheds. Databases comprising soil attributes, agricultural land use, and light detection and ranging-derived elevation models were developed for two glaciated midwestern HUC12 watersheds: Iowa's Beaver Creek watershed has an older dissected landscape, and Lime Creek in Illinois is young and less dissected. Subsurface drainage is common in both watersheds. We identified locations for conservation practices, including in-field practices (grassed waterways), edge-of-field practices (nutrient-removal wetlands, saturated buffers), and drainage-water management, by applying terrain analyses, geographic criteria, and cross-classifications to field- and watershed-scale geographic data. Cover crops were randomly distributed to fields without geographic prioritization. A set of alternative planning scenarios was developed to represent a variety of extents of implementation among these practices. The scenarios were assessed for nutrient reduction potential using a spreadsheet approach to calculate the average nutrient-removal efficiency required among the practices included in each scenario to achieve a 40% NO-N reduction. Results were evaluated in the context of the Iowa Nutrient Reduction Strategy, which reviewed nutrient-removal efficiencies of practices and established the 40% NO-N reduction as Iowa's target for Gulf of Mexico hypoxia mitigation by agriculture. In both test watersheds, planning scenarios that could potentially achieve the targeted NO-N reduction but remove <5% of cropland from production were identified. Cover crops and nutrient removal wetlands were common to these scenarios. This approach provides an interim technology to assist local watershed planning and could provide planning scenarios to evaluate using watershed simulation models. A set of ArcGIS tools is being released to enable transfer of this mapping technology. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effect of available nitrogen on phytoavailability and bioaccumulation of hexavalent and trivalent chromium in hankow willows (Salix matsudana Koidz).

PubMed

Yu, Xiao-Zhang; Gu, Ji-Dong

2008-06-01

The effect of available nitrogen in nutrient solution on removal of two chemical forms of chromium (Cr) by plants was investigated. Pre-rooted hankow willows (Salix matsudana Koidz) were grown in a hydroponic solution system with or without nitrogen, and amended with hexavalent chromium [Cr (VI)] or trivalent chromium [Cr (III)] at 25.0+/-0.5 degrees C for 192 h. The results revealed that higher removal of Cr by plants was achieved from the hydroponic solutions without any nitrogen than those containing nitrogen. Although faster removal of Cr (VI) than Cr (III) was observed, translocation of Cr (III) within plant materials was more efficient than Cr (VI). Substantial difference existed in the distribution of Cr in different parts of plant tissues due to the nitrogen in nutrient solutions (p<0.05): lower stems were the major sink for both Cr species in willows grown in the N-free nutrient solutions and more Cr was accumulated in the roots of plants in N-containing ones. No significant difference was found in the removal rate of Cr (VI) between willows grown in the N-free and N-containing solutions (p>0.05). Removal rates of Cr (III) decreased linearly with the strength of nutrient solutions with or without N addition (p<0.01). Translocation efficiencies of both Cr species increased proportionally with the strength of N-containing nutrient solutions and decreased with the strength of N-free nutrient solutions. Results suggest that uptake and translocation mechanisms of Cr (VI) and Cr (III) are apparently different in hankow willows. The presence of easily available nitrogen and other nutrient elements in the nutrient solutions had a more pronounced influence on the uptake of Cr (III) than Cr (VI). Nitrogen availability and quantities in the ambient environment will affect the translocation of both Cr species and their distribution in willows in phytoremediation.

Switchgrass growth and effects on biomass accumulation, moisture content, and nutrient removal

USDA-ARS?s Scientific Manuscript database

Temporal patterns of plant growth, composition, and nutrient removal impact development of models for predicting optimal harvest times of switchgrass (Panicum virgatum L.) for bioenergy. Objectives were to characterize seasonal trends in yield, tissue moisture, ash content, leaf area index (LAI), in...

Wastewater treatment in the pulp-and-paper industry: A review of treatment processes and the associated greenhouse gas emission.

PubMed

Ashrafi, Omid; Yerushalmi, Laleh; Haghighat, Fariborz

2015-08-01

Pulp-and-paper mills produce various types of contaminants and a significant amount of wastewater depending on the type of processes used in the plant. Since the generated wastewaters can be potentially polluting and very dangerous, they should be treated in wastewater treatment plants before being released to the environment. This paper reviews different wastewater treatment processes used in the pulp-and-paper industry and compares them with respect to their contaminant removal efficiencies and the extent of greenhouse gas (GHG) emission. It also evaluates the impact of operating parameters on the performance of different treatment processes. Two mathematical models were used to estimate GHG emission in common biological treatment processes used in the pulp-and-paper industry. Nutrient removal processes and sludge treatment are discussed and their associated GHG emissions are calculated. Although both aerobic and anaerobic biological processes are appropriate for wastewater treatment, their combination known as hybrid processes showed a better contaminant removal capacity at higher efficiencies under optimized operating conditions with reduced GHG emission and energy costs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents

PubMed Central

Jasper, Justin T.; Nguyen, Mi T.; Jones, Zackary L.; Ismail, Niveen S.; Sedlak, David L.; Sharp, Jonathan O.; Luthy, Richard G.; Horne, Alex J.; Nelson, Kara L.

2013-01-01

Abstract Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe. PMID:23983451

Unit Process Wetlands for Removal of Trace Organic Contaminants and Pathogens from Municipal Wastewater Effluents.

PubMed

Jasper, Justin T; Nguyen, Mi T; Jones, Zackary L; Ismail, Niveen S; Sedlak, David L; Sharp, Jonathan O; Luthy, Richard G; Horne, Alex J; Nelson, Kara L

2013-08-01

Treatment wetlands have become an attractive option for the removal of nutrients from municipal wastewater effluents due to their low energy requirements and operational costs, as well as the ancillary benefits they provide, including creating aesthetically appealing spaces and wildlife habitats. Treatment wetlands also hold promise as a means of removing other wastewater-derived contaminants, such as trace organic contaminants and pathogens. However, concerns about variations in treatment efficacy of these pollutants, coupled with an incomplete mechanistic understanding of their removal in wetlands, hinder the widespread adoption of constructed wetlands for these two classes of contaminants. A better understanding is needed so that wetlands as a unit process can be designed for their removal, with individual wetland cells optimized for the removal of specific contaminants, and connected in series or integrated with other engineered or natural treatment processes. In this article, removal mechanisms of trace organic contaminants and pathogens are reviewed, including sorption and sedimentation, biotransformation and predation, photolysis and photoinactivation, and remaining knowledge gaps are identified. In addition, suggestions are provided for how these treatment mechanisms can be enhanced in commonly employed unit process wetland cells or how they might be harnessed in novel unit process cells. It is hoped that application of the unit process concept to a wider range of contaminants will lead to more widespread application of wetland treatment trains as components of urban water infrastructure in the United States and around the globe.

Minimizing nitrous oxide in biological nutrient removal from municipal wastewater by controlling copper ion concentrations.

PubMed

Zhu, Xiaoyu; Chen, Yinguang; Chen, Hong; Li, Xiang; Peng, Yongzhen; Wang, Shuying

2013-02-01

In this study, nitrous oxide (N(2)O) production during biological nutrient removal (BNR) from municipal wastewater was reported to be remarkably reduced by controlling copper ion (Cu(2+)) concentration. Firstly, it was observed that the addition of Cu(2+) (10-100 μg/L) reduced N(2)O generation by 54.5-73.2 % and improved total nitrogen removal when synthetic wastewater was treated in an anaerobic-aerobic (with low dissolved oxygen) BNR process. Then, the roles of Cu(2+) were investigated. The activities of nitrite and nitrous oxide reductases were increased by Cu(2+) addition, which accelerated the bio-reductions of both nitrite to nitric oxide (NO (2) (-)  → NO) and nitrous oxide to nitrogen gas (N(2)O → N(2)). The quantitative real-time polymerase chain reaction assay indicated that Cu(2+) addition increased the number of N(2)O reducing denitrifiers. Further investigation showed that more polyhydoxyalkanoates were utilized in the Cu(2+)-added system for denitrification. Finally, the feasibility of reducing N(2)O generation by controlling Cu(2+) was examined in two other BNR processes treating real municipal wastewater. As the Cu(2+) in municipal wastewater is usually below 10 μg/L, according to this study, the supplement of influent Cu(2+) to a concentration of 10-100 μg/L is beneficial to reduce N(2)O emission and improve nitrogen removal when sludge concentration in the BNR system is around 3,200 mg/L.

Effects of wastewater effluent discharge and treatment facility upgrades on environmental and biological conditions of Indian Creek, Johnson County, Kansas, June 2004 through June 2013

USGS Publications Warehouse

Graham, Jennifer L.; Stone, Mandy L.; Rasmussen, Teresa J.; Foster, Guy M.; Poulton, Barry C.; Paxson, Chelsea R.; Harris, Theodore D.

2014-01-01

Indian Creek is one of the most urban drainage basins in Johnson County, Kansas, and environmental and biological conditions of the creek are affected by contaminants from point and other urban sources. The Johnson County Douglas L. Smith Middle Basin (hereafter referred to as the “Middle Basin”) and Tomahawk Creek Wastewater Treatment Facilities (WWTFs) discharge to Indian Creek. In summer 2010, upgrades were completed to increase capacity and include biological nutrient removal at the Middle Basin facility. There have been no recent infrastructure changes at the Tomahawk Creek facility; however, during 2009, chemically enhanced primary treatment was added to the treatment process for better process settling before disinfection and discharge with the added effect of enhanced phosphorus removal. The U.S. Geological Survey, in cooperation with Johnson County Wastewater, assessed the effects of wastewater effluent on environmental and biological conditions of Indian Creek by comparing two upstream sites to four sites located downstream from the WWTFs using data collected during June 2004 through June 2013. Environmental conditions were evaluated using previously and newly collected discrete and continuous data and were compared with an assessment of biological community composition and ecosystem function along the upstream-downstream gradient. This study improves the understanding of the effects of wastewater effluent on stream-water and streambed sediment quality, biological community composition, and ecosystem function in urban areas. After the addition of biological nutrient removal to the Middle Basin WWTF in 2010, annual mean total nitrogen concentrations in effluent decreased by 46 percent, but still exceeded the National Pollutant Discharge Elimination System (NPDES) wastewater effluent permit concentration goal of 8.0 milligrams per liter (mg/L); however, the NPDES wastewater effluent permit total phosphorus concentration goal of 1.5 mg/L or less was achieved at the Middle Basin WWTF. At the Tomahawk Creek WWTF, after the addition of chemically enhanced primary treatment in 2009, effluent discharges also had total phosphorus concentrations below 1.5 mg/L. After the addition of biological nutrient removal, annual total nitrogen and phosphorus loads from the Middle Basin WWTF decreased by 42 and 54 percent, respectively, even though effluent volume increased by 11 percent. Annual total phosphorus loads from the Tomahawk Creek WWTF after the addition of chemically enhanced primary treatment decreased by 54 percent despite a 33-percent increase in effluent volume. Total nitrogen and phosphorus from the WWTFs contributed between 30 and nearly 100 percent to annual nutrient loads in Indian Creek depending on streamflow conditions. In-stream total nitrogen primarily came from wastewater effluent except during years with the highest streamflows. Most of the in-stream total phosphorus typically came from effluent during dry years and from other urban sources during wet years. During 2010 through 2013, annual mean discharge from the Middle Basin WWTF was about 75 percent of permitted design capacity. Annual nutrient loads likely will increase when the facility is operated at permitted design capacity; however, estimated maximum annual nutrient loads from the Middle Basin WWTF were 27 to 38 percent lower than before capacity upgrades and the addition of biological nutrient removal to treatment processes. Thus, the addition of biological nutrient removal to the Middle Basin wastewater treatment process should reduce overall nutrient loads from the facility even when the facility is operated at permitted design capacity. The effects of wastewater effluent on the water quality of Indian Creek were most evident during below-normal and normal streamflows (about 75 percent of the time) when wastewater effluent represented about 24 percent or more of total streamflow. Wastewater effluent had the most substantial effect on nutrient concentrations in Indian Creek. Total and inorganic nutrient concentrations at the downstream sites during below-normal and normal streamflows were 10 to 100 times higher than at the upstream sites, even after changes in treatment practices at the WWTFs. Median total phosphorus concentrations during below-normal and normal streamflows at a downstream site were 43 percent lower following improvements in wastewater treatment processes. Similar decreases in total nitrogen were not observed, likely because total nitrogen concentrations only decreased in Middle Basin effluent and wastewater contributed a higher percentage to streamflows when nutrient samples were collected during the after-upgrade period. The wastewater effluent discharges to Indian Creek caused changes in stream-water quality that may affect biological community structure and ecosystem processes, including higher concentrations of bioavailable nutrients (nitrate and orthophosphorus) and warmer water temperatures during winter months. Other urban sources of contaminants also caused changes in stream-water quality that may affect biological community structure and ecosystem processes, including higher turbidities downstream from construction areas and higher specific conductance and chloride concentrations during winter months. Chloride concentrations exceeded acute and chronic exposure criteria at all Indian Creek study sites, regardless of wastewater influence, for weeks or months during winter. Streambed sediment chemistry was affected by wastewater (elevated nutrient and organic wastewater-indicator compound concentrations) and other contaminants from urban sources (elevated polyaromatic hydrocarbon concentrations). Overall habitat conditions were suboptimal or marginal at all sites; general decline in habitat conditions along the upstream-downstream gradient likely was caused by the cumulative effects of urbanization with increasing drainage basin size. Wastewater effluent likely affected algal periphyton biomass and community composition, primary production, and community respiration in Indian Creek. Functional stream health, evaluated using a preliminary framework based on primary production and community respiration, was mildly or severely impaired at most downstream sites relative to an urban upstream Indian Creek site. The mechanistic cause of the changes in these biological variables are unclear, though elevated nutrient concentrations were positively correlated with algal biomass, primary production, and community respiration. Macroinvertebrate communities indicated impairment at all sites, and Kansas Department of Health and Environment aquatic life support scores indicated conditions nonsupporting of aquatic life, regardless of wastewater influences. Urban influences, other than wastewater effluent discharge, likely control macroinvertebrate community structure in Indian Creek. Changes in treatment processes at the Middle Basin and Tomahawk Creek WWTFs improved wastewater effluent quality and decreased nutrient loads, but wastewater effluent discharges still had negative effects on the environmental and biological conditions at downstream Indian Creek sites. Wastewater effluent discharge into Indian Creek likely contributed to changes in measures of ecosystem structure (streamflow, water and streambed-sediment chemistry, algal biomass, and algal periphyton community composition) and function (primary production and community respiration) along the upstream-downstream gradient. Wastewater effluent discharges maintained streamflows and increased nutrient concentrations, algal biomass, primary production, and community respiration at the downstream sites. Functional stream health was severely impaired downstream from the Middle Basin WWTF and mildly impaired downstream from the Tomahawk WWTF relative to the urban upstream site. As distance from the Middle Basin WWTF increased, nutrient concentrations, algal biomass, primary production, and community respiration decreased, and functional stream health was no longer impaired 9.5 kilometers downstream from the discharge relative to the urban upstream site. Therefore, although wastewater effluent caused persistent changes in environmental and biological conditions and functional stream health at sites located immediately downstream from WWTF effluent discharges, some recovery to conditions more similar to the urban upstream site occurred within a relatively short distance.

Macroscopic and microscopic variation in recovered magnesium phosphate materials: Implications for phosphorus removal processes and product re-use

USDA-ARS?s Scientific Manuscript database

Phosphorus (P) recovery and re-use will become increasingly important for water quality protection and sustainable nutrient cycling as environmental regulations become stricter and global P reserves decline. The objective of this study was to examine and characterize several magnesium phosphates re...

The use of food waste as a carbon source for on-site treatment of nutrient-rich blackwater from an office block.

PubMed

Tannock, Simon J C; Clarke, William P

2016-09-01

Wastewater from office blocks is typically dominated by blackwater and is therefore concentrated and nutrient-rich. A pilot plant was operated for 260 days, receiving 300 L d(-1) of wastewater directly from an office building to determine whether nutrient removal could be achieved using food waste (FW) as a supplemental carbon source. The pilot plant consisted of a 600 L prefermenter and a 600 L membrane bioreactor that was operated as a sequential batch reactor in order to cycle through anoxic, anaerobic and aerobic phases. The influent wastewater Chemical Oxygen Demand (COD)/N/P was, on average, 1438/275/40 mg L(-1), considerably higher than typical municipal wastewater. Treatment trials on the wastewater alone showed that the COD was only marginally sufficient to exhaust nitrate, and initiate anaerobic conditions required for phosphate removal. The addition of 15 kg d(-1) of macerated FW increased the average influent COD/N/P concentrations to 20,072/459/66 mg L(-1). The suitability of FW as a carbon source was demonstrated by denitrification to NOx-N concentration of <1 mg L(-1) during the biological nutrient removal (BNR) cycles. N removal was limited by nitrification. FW also induced the anaerobic phase within the BNR cycles necessary for P removal. The final average COD (non-recalcitrant)/N/P effluent concentrations under FW supplementation were 7/50/13 mg L(-1) which equates to 99%, 89% and 80% COD/N/P removal, respectively, meeting the highest nutrient removal efficiency standards stipulated by state jurisdictions for on-site systems in the USA.

A study of photosynthetic biogas upgrading based on a high rate algal pond under alkaline conditions: Influence of the illumination regime.

PubMed

Franco-Morgado, Mariana; Alcántara, Cynthia; Noyola, Adalberto; Muñoz, Raúl; González-Sánchez, Armando

2017-08-15

Microalgal-bacterial processes have emerged as environmental friendly systems for the cost-effective treatment of anaerobic effluents such as biogas and nutrients-laden digestates. Environmental parameters such as temperature, irradiation, nutrient concentration and pH effect the performance of the systems. In this paper, the potential of a microalgal-bacterial photobioreactor operated under high pH (≈9.5) and high alkalinity to convert biogas into biomethane was evaluated. The influence of the illumination regime (continuous light supply vs 12h/12h light/dark cycles) on the synthetic biogas upgrading efficiency, biomass productivity and nutrient removal efficiency was assessed in a High-Rate Algal Pond interconnected to a biogas absorption bubble column. No significant differences in the removal efficiency of CO 2 and H 2 S (91.5±2% and 99.5%±0.5, respectively) were recorded regardless of the illumination regime. The high fluctuations of the dissolved oxygen concentration during operation under light/dark cycles allowed to evaluate the specific growth rate and the specific partial degradation rate of the microalgae biomass by photosynthesis and respiration, respectively. The respiration reduced the net microalgae biomass productivity under light/dark cycles compared with process operation under the continuous light supply. Copyright © 2017 Elsevier B.V. All rights reserved.

Full-scale experiences of nitrogen removal of fish-processing wastewater with flotation and anoxic-aerobic activated sludge system.

PubMed

Steinke, M; Barjenbruch, M

2010-01-01

This article presents full scale experience of one of the largest fish-processing factories in Europe with a production capacity of about 50,000 tons herring per year and a maximum daily wastewater discharge of 1,500 m(3). The wastewater treatment plant is the only direct discharger in the fish-processing industry in Germany. Thus, very low effluent values have to be keep in, especially the nitrogen reduction has to be operated during the whole year even when the temperature is low. The central point of the multi-stage WWTP (about 90,000 PE) is the biological nutrient removal (BNR) with pre-denitrification. The wastewater pre-treatment with sieves (0.8 mm) and a two staged flotation reduces the nitrogen load - mainly the particle bounded fraction - but the optimal nutrient ratios for biological treatment need to be observed. The activated sludge system has maximum OLR of 0.12 g COD/(g MLSS d) and NLR of 0.015 g TN/(g MLSS d) but a "Stand-By"-Operation with periods without wastewater influent is unavoidable. Discontinuous operating is one problem. The dependence on temperature as one of the main influences of nitrification-activity is the second point. The article gives an overview about the start-up and the optimisation of the process.

High diversity within the periphyton community of an algal turf scrubber on the Susquehanna River

USDA-ARS?s Scientific Manuscript database

Algal turf scrubber systems have been evaluated for their ability to remove dissolved nutrients from a variety of natural waters and agricultural wastewaters. Although these systems have been well characterized with respect to productivity and nutrient removal, very little is known about the commun...

Cultivation of Chlorella vulgaris in a pilot-scale photobioreactor using real centrate wastewater with waste glycerol for improving microalgae biomass production and wastewater nutrients removal.

PubMed

Ren, Hongyan; Tuo, Jinhua; Addy, Min M; Zhang, Renchuan; Lu, Qian; Anderson, Erik; Chen, Paul; Ruan, Roger

2017-12-01

To improve nutrients removal from real centrate wastewater and enhance the microalgae biomass production, cultivation of Chlorella vulgaris in lab and a pilot-scale photobioreactor with waste glycerol was studied. The results showed the optimal concentration of the crude glycerol was 1.0gL -1 with the maximum biomass productivity of 460mgL -1 d -1 TVS, the maximum lipid content of 27%, the nutrient removal efficiency of all above 86%, due to more balanced C/N ratio. The synergistic relationship between the wastewater-borne bacteria and the microalgae had significant good influence on nutrient removal. In pilot-scale wastewater-based algae cultivation, with 1gL -1 waste glycerol addition, the average biomass production of 16.7gm -2 d -1 , lipid content of 23.6%, and the removal of 2.4gm -2 d -1 NH 4 + -N, 2.7gm -2 d -1 total nitrogen, 3.0gm -2 d -1 total phosphorous, and 103.0gm -2 d -1 of COD were attained for 34days semi-continuous mode. Copyright © 2017 Elsevier Ltd. All rights reserved.

Struvite Precipitation as a Means of Recovering Nutrients and Mitigating Ammonia Toxicity in a Two-Stage Anaerobic Digester Treating Protein-Rich Feedstocks.

PubMed

Wang, Shunli; Hawkins, Gary L; Kiepper, Brian H; Das, Keshav C

2016-08-03

Accumulation of ammonia, measured as total ammonia nitrogen (TAN), a product of protein decomposition in slaughterhouse wastes, inhibits the anaerobic digestion process, reducing digester productivity and leading to failure. Struvite precipitation (SP) is an effective means to remove TAN and enhance the buffering of substrates. Different Mg and P sources were evaluated as reactants in SP in acidogenic digester effluents to reduce its TAN levels. In order to measure impact of TAN removal, a standard biochemical methane potential (BMP) test was conducted to measure methane yield from treatments that had the highest TAN reductions. SP results showed 6 of 9 reagent combinations resulted in greater than 70% TAN removal. The BMP results indicated that SP treatment by adding Mg(OH)₂ and H₃PO₄ resulted in 57.6% nitrogen recovery and 41.7% increase in methane yield relative to the substrate without SP. SP is an effective technology to improve nutrient recovery and methane production from the anaerobic digestion of protein-rich feedstocks.

Advanced wastewater treatment using microalgae: effect of temperature on removal of nutrients and organic carbon

NASA Astrophysics Data System (ADS)

Mohamad, Shurair; Fares, Almomani; Judd, Simon; Bhosale, Rahul; Kumar, Anand; Gosh, Ujjal; Khreisheh, Majeda

2017-05-01

This study evaluated the use of mixed indigenous microalgae (MIMA) as a treatment process for wastewaters and CO2 capturing technology at different temperatures. The study follows the growth rate of MIMA, CO2 Capturing from flue gas, removals of organic matter and nutrients from three types of wastewater (primary effluent, secondary effluent and septic effluent). A noticeable difference between the growth patterns of MIMA was observed at different CO2 and different operational temperatures. MIMA showed the highest growth grate when injected with CO2 dosage of 10% compared to the growth for the systems injected with 5% and 15 % of CO2. Ammonia and phosphorus removals for Spirulina were 69%, 75%, and 83%, and 20%, 45% and 75 % for the media injected with 0, 5 and 10% CO2. The results of this study show that simple and cost-effective microalgae-based wastewater treatment systems can be successfully employed at different temperatures as a successful CO2 capturing technology even with the small probability of inhibition at high temperatures.

Biocapture of CO2 by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods

PubMed Central

Guo, Pengfei; Zhang, Yuejin; Zhao, Yongjun

2018-01-01

Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO2 in biogas. The microalgae–fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulgaris–Ganoderma lucidum > Chlorella vulgaris–activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m−2 s−1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology. PMID:29543784

Evaluating the effect of different draw solutes in a baffled osmotic membrane bioreactor-microfiltration using optical coherence tomography with real wastewater.

PubMed

Pathak, Nirenkumar; Fortunato, Luca; Li, Sheng; Chekli, Laura; Phuntsho, Sherub; Ghaffour, Noreddine; Leiknes, TorOve; Shon, Ho Kyong

2018-05-02

This study investigated the performance of an integrated osmotic and microfiltration membrane bioreactor for real sewage employing baffles in the reactor. To study the biofouling development on forward osmosis membranes optical coherence tomography (OCT) technique was employed. On-line monitoring of biofilm growth on a flat sheet cellulose triacetate forward osmosis (CTA-FO) membrane was conducted for 21 days. Further, the process performance was evaluated in terms of water flux, organic and nutrient removal, microbial activity in terms of soluble microbial products (SMP) and extracellular polymeric substance (EPS), and floc size. The measured biofouling layer thickness was in the order sodium chloride (NaCl) > ammonium sulfate (SOA) > potassium dihydrogen phosphate (KH 2 PO 4 ). Very high organic removal (96.9 ± 0.8%) and reasonably good nutrient removal efficiency (85.2 ± 1.6% TN) was achieved. The sludge characteristics and biofouling layer thickness suggest that less EPS and higher floc size were the governing factors for less fouling. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biocapture of CO₂ by Different Microalgal-Based Technologies for Biogas Upgrading and Simultaneous Biogas Slurry Purification under Various Light Intensities and Photoperiods.

PubMed

Guo, Pengfei; Zhang, Yuejin; Zhao, Yongjun

2018-03-15

Abstract : Co-cultivation of microalgae and microbes for pollutant removal from sewage is considered as an effective wastewater treatment method. The aim of this study is to screen the optimal photoperiod, light intensity and microalgae co-cultivation method for simultaneously removing nutrients in biogas slurry and capturing CO₂ in biogas. The microalgae-fungi pellets are deemed to be a viable option because of their high specific growth rate and nutrient and CO 2 removal efficiency under the photoperiod of 14 h light:10 h dark. The order of both the biogas slurry purification and biogas upgrading is ranked the same, that is Chlorella vulga ris - Ganoderma lucidum > Chlorella vulga ris -activated sludge > Chlorella vulgaris under different light intensities. For all cultivation methods, the moderate light intensity of 450 μmol m -2 s -1 is regarded as the best choice. This research revealed that the control of photoperiod and light intensity can promote the biological treatment process of biogas slurry purification and biogas upgrading using microalgal-based technology.

Performance of five plant species in removal of nitrogen and phosphorus from an experimental phytoremediation system in the Ningxia irrigation area.

PubMed

Chen, Chongjuan; Zhao, Tiancheng; Liu, Ruliang; Luo, Liangguo

2017-09-10

Agricultural non-point source (ANPS) pollution is an important contributor to elevated nitrogen (N) and phosphorus (P) in surface waters, which can cause serious environmental problems. Considerable effort has therefore gone into the development of methods that control the ANPS input of N and P to surface waters. Phytoremediation has been extensively used because it is cost-effective, environmentally friendly, and efficient. The N and P loads from agricultural drainage are a potential threat to the water quality of the Yellow River in Ningxia, China. Yet, phytoremediation has only rarely been applied within the Ningxia irrigation area. In an experimental set-up, five species (Ipomoea aquatica, IA; Lactuca sativa, LS; Oryza sativa, OS; Typha latifolia, TL; Zizania latifolia, ZL) were evaluated for their ability to reduce N and P loads over 62 days and five observation periods. Total N and P concentrations, plant biomass, and nutrient content were measured. The results showed that OS, LS, and IA performed better than ZL and TL in terms of nutrients removal, biomass accumulation, and nutrients storage. The highest overall removal rates of N and P (57.7 and 57.3%, respectively) were achieved by LS treatment. In addition, plant uptake contributed significantly to nutrient removal, causing a 25.9-72.0% reduction in N removal and a 54.3-86.5% reduction in P removal. Thus, this study suggests that OS, LS, and IA would be more suitable than ZL and TL for controlling nutrient loads in the Ningxia irrigation area using phytoremediation.

Nutrient removal from swine lagoon effluent by duckweed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bergmann, B.A.; Cheng, J.; Classen, J.

2000-04-01

Three duckweed geographic isolates were grown on varying concentrations of swine lagoon effluent in a greenhouse to determine their ability to remove nutrients from the effluent. Duckweed biomass was harvested every other day over a 12-day period. Duckweed biomass production, nutrient loss from the swine lagoon effluent, and nutrient content of duckweed biomass were used to identify effluent concentrations/geographic isolate combinations that are effective in terms of nutrient utilization from swine lagoon effluent and production of healthy duckweed biomass. When Lemna minor geographic isolate 8627 was grown on 50% swine lagoon effluent, respective losses of TKN, NH{sub 3}-N, TP, OPO{submore » 4}-P, TOC, K, Cu, and Zn were 83, 100, 49, 31, 68, 21, 28 and 67%.« less

Removal of Plant Nutrients by Means of Aerobic Stabilization of Sludge

PubMed Central

Irgens, Roar L.; Halvorson, H. Orin

1965-01-01

In the conventional treatment of sewage, the solids are normally disposed of by anaerobic digestion. This leaves a considerable amount of plant nutrients, such as nitrogen and phosphate, as soluble compounds which will eventually find their way into the plant's final effluent, since the supernatant fluid from the digesters is normally returned to the raw sewage. In a recent investigation, we found that, if the sludges were treated by an aerobic process, a significant portion of the carbonaceous matter was oxidized to carbon dioxide and water, and the rest was assimilated into microbial protoplasm. This process tied up the available nitrogen and phosphorus so that practically none remained dissolved in the suspending liquid. The accumulated solids, consisting mostly of microbial cells, were separated very easily from the liquid, leaving a slightly colored supernatant fluid that was water-clear, free from plant nutrients, and very low in BOD and COD. The overall process was accomplished in a detention time not exceeding 20 days, in contrast to anaerobic digestion which requires from 50 to 70 days. PMID:14325277

Electrolytic Removal of Nitrate From CELSS Crop Residues

NASA Technical Reports Server (NTRS)

Colon, Guillermo; Sager, John

1996-01-01

The controlled ecological life support system (CELSS) resource recovery system is a waste processing system using aerobic and anaerobic bioreactors to recover plant nutrients and secondary foods from inedible biomass. Crop residues contain significant amounts of nitrate which presents two problems: (1) both CELSS biomass production and resource recovery consume large quantities of nitric acid, (2) nitrate causes a variety of problems in both aerobic and anaerobic bioreactors. A technique was proposed to remove the nitrate from potato inedible biomass leachate and to satisfy the nitric acid demand using a four compartment electrolytic cell.

Microalgae biomass growth using primary treated wastewater as nutrient source and their potential use for lipids production

NASA Astrophysics Data System (ADS)

Frementiti, Anastacia; Aravantinou, Andriana F.; Manariotis, Ioannis D.

2015-04-01

The great demand for energy, the rising price of the crude oil and the rapid decrease of the supply of fossil fuels are the main reasons that have increased the interest for the production of fuels from renewable resources. Microalgae are considered to be the most promising new source of biomass and biofuels, since their lipid content in some cases is up to 70%. The microalgal growth and its metabolism processes are essential in wastewater treatment with many economical prospects. The aim of this work was to evaluate the algal production in a laboratory scale open pond. The pond had a working volume of 30 L and was fed with sterilized primary treated wastewater. Chlorococcum sp. was used as a model microalgal. Experiments were conducted under controlled environmental conditions in order to investigate the removal of nutrients, biomass growth, and lipids accumulation in microalgae. Chlorococcum sp. cultures behavior was investigated under batch, fill and draw, and continuous operation mode, at two different radiation intensities (100 and 200 μmol/m2s). The maximum biomass concentration of 630 mg/L was observed with the fill and draw mode. Moreover, the growth rates of microalgal biomass were depended on the influent nutrients concentration. Specifically, the phosphates were the limiting factor for biomass growth in continuous condition; the phosphates removal in this condition, reached a 100%. Chemical demand oxygen (COD) was not removed efficiently by Chlorococcum sp. since it was an autotrophic microalgal with no organic carbon demands for its growth. The lipids content in the dry weight of Chlorococcum sp. ranged from 1 to 9% depending on the concentration of nutrients and the operating conditions.

A shallow lake remediation regime with Phragmites australis: Incorporating nutrient removal and water evapotranspiration.

PubMed

Zhao, Ying; Yang, Zhifeng; Xia, Xinghui; Wang, Fei

2012-11-01

Shallow lake eutrophication has been an important issue of global water environment. Based on the simulation and field sampling experiments in Baiyangdian Lake, the largest shallow lake in North China, this study proposed a shallow lake remediation regime with Phragmites australis (reed) incorporating its opposite effects of nutrient removal and water evapotranspiration on water quality. The results of simulation experiments showed that both total nitrogen (TN) and phosphorus (TP) removal efficiencies increased with the increasing reed coverage. The TN removal efficiencies by reed aboveground uptake and rhizosphere denitrification were 11.2%, 13.8%, 22.6%, 28.4%, and 29.6% for the reed coverage of 20%, 40%, 60%, 80%, and 100%, respectively. Correspondingly, TP removal efficiencies by aboveground reed uptake were 1.4%, 2.5%, 4.4%, 7.4% and 7.9%, respectively. However, the water quality was best when the reed coverage was 60% (72 plants m(-2)). This was due to the fact that the concentration effect of reed evapotranspiration on nutrient increased with reed coverage. When the reed coverage was 100% (120 plants m(-2)), the evapotranspiration was approximately twice that without reeds. The field sampling results showed that the highest aboveground nutrient storages occurred in September. Thus, the proposed remediation regime for Baiyangdian Lake was that the reed coverage should be adjusted to 60%, and the aboveground biomass of reeds should be harvested in each September. With this remediation regime, TN and TP removal in Baiyangdian Lake were 117.8 and 4.0 g m(-2), respectively, and the corresponding removal efficiencies were estimated to be 49% and 8.5% after six years. This study suggests that reed is an effective plant for the remediation of shallow lake eutrophication, and its contrasting effects of nutrient removal and evapotranspiration on water quality should be considered for establishing the remediation regime in the future. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simultaneous Removal of Nitrogen and Phosphorus from Stormwater by ZeroValent Iron and Biochar in Bioretention Cells (Part 1)

DOT National Transportation Integrated Search

2016-06-03

Nutrients (N and P) in stormwater are a major cause of water quality impairments in the U.S. Current technologies such as bioretention cells to treat stormwater from roadways do not always remove nutrients sufficiently, and additional land may be nee...

Isolation of a bacterial strain, Acinetobacter sp. from centrate wastewater and study of its cooperation with algae in nutrients removal.

PubMed

Liu, Hui; Lu, Qian; Wang, Qin; Liu, Wen; Wei, Qian; Ren, Hongyan; Ming, Caibing; Min, Min; Chen, Paul; Ruan, Roger

2017-07-01

Algae were able to grow healthy on bacteria-containing centrate wastewater in a pilot-scale bioreactor. The batch experiment indicated that the co-cultivation of algae and wastewater-borne bacteria improved the removal efficiencies of chemical oxygen demand and total phosphorus in centrate wastewater to 93.01% and 98.78%, respectively. A strain of beneficial aerobic bacteria, Acinetobacter sp., was isolated and its biochemical characteristics were explored. Synergistic cooperation was observed in the growth of algae and Acinetobacter sp. Removal efficiencies of some nutrients were improved significantly by the co-cultivation of algae and Acinetobacter sp. After treatment, residual nutrients in centrate wastewater reached the permissible discharge limit. The cooperation between algae and Acinetobacter sp. was in part attributed to the exchange of carbon dioxide and oxygen between the algae and bacteria. This synergetic relationship between algae and Acinetobacter sp. provided a promising way to treat the wastewater by improving the nutrients removal and biomass production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nutrient removal and lipid production by Coelastrella sp. in anaerobically and aerobically treated swine wastewater.

PubMed

Luo, Le; He, Huijun; Yang, Chunping; Wen, Shan; Zeng, Guangming; Wu, Mengjie; Zhou, Zili; Lou, Wei

2016-09-01

Coelastrella sp. QY01, a microalgae species isolated from a local pond, was identified and used for the treatment of anaerobically and aerobically treated swine wastewater (AnATSW). Microalgal growth characteristics, nutrient removal and lipid accumulation of QY01 cultivated in the initial concentration of AnATSW ranged from 63 to 319mg NH3-N/L were examined. The specific growth rate of QY01 cultivated in cultures ranged from 0.269 to 0.325day(-1) with a biomass productivity from 42.77 to 57.46mgL(-1)day(-1). Removal rates for NH3-N, TP and inorganic carbon in AnATSW at the various nutrient concentrations ranged from 90% to 100%, from 90% to 100% and from 74% to 78%, respectively. The lipid content of QY01 ranged from 22.4% to 24.8%. The lipid productivity was positive correlation with the biomass productivity. 40% AnATSW was optimal for QY01 cultivation, in which nutrient removal and productivity of biomass and lipid were maximized. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Temperature and Nutrient Concentration on Survival of Foodborne Pathogens in Deciduous Fruit Processing Environments for Effective Hygiene Management.

PubMed

Duvenage, Stacey; Korsten, Lise

2016-11-01

Temperature and good sanitation practices are important factors for controlling growth of microorganisms. Fresh produce is stored at various temperatures to ensure quality and to prolong shelf life. When foodborne pathogens survive and grow on fresh produce at storage temperatures, then additional control strategies are needed to inactivate these pathogens. The aim of this study was to determine how temperatures associated with deciduous fruit processing and storage facilities (0.5, 4, and 21°C) affect the growth and/or survival of Escherichia coli O157:H7, Listeria monocytogenes , Salmonella enterica subsp. enterica serovar Typhimurium, and Staphylococcus aureus under different nutrient conditions (nutrient rich and nutrient poor) and on simulated contact surfaces (vinyl coupons). Information on the growth and survival of foodborne pathogens at specific deciduous fruit processing and storage temperatures (0.5°C) is not available. All pathogens except E. coli O157:H7 were able to survive on vinyl coupons at all temperatures. L. monocytogenes proliferated under both nutrient conditions independent of temperature. S. aureus was the pathogen least affected by nutrient conditions. The survival of foodborne pathogens on the vinyl coupons, a model system for studying surfaces in fruit preparation and storage environments, indicates the potential for cross-contamination of deciduous fruit products under poor sanitation conditions. Foodborne pathogens that can proliferate and survive at various temperatures under different nutrient conditions could lead to fruit cross-contamination. Temperature mismanagement, which could allow pathogen proliferation in contaminated fruit packing houses and storage environments, is a concern. Therefore, proper hygiene and sanitation practices, removal of possible contaminants, and proper food safety management systems are needed to ensure food safety.

Nutrient removal by root zone treatment systems: a review.

PubMed

Sonavane, P G; Munavalli, G R; Ranade, S V

2008-07-01

The Root Zone Treatment System (RZTS) has been used widely for nutrient removal in European countries. In spite of having its more adaptability in tropical region like India its use to address nutrient induced issues in the country is very less. The lack of widely accepted data, non consensus of scientists over nutrient removal mechanism and inability to apply performance standards observed in other countries directly might have hampered the acceptance of this technology in India. A few technology assessment programs are being conducted in collaboration with other countries to engineer this technology but nutrient removal aspects are not essentially focused. In this context, there is need to direct lab scale research to identify potential wetland plants, bed media and comparative study of their combination specific performance under similar conditions. The field application of the data will help to understand variability in performance and disparities in the mechanism. The systems would be amended based on these studies to establish combination specific performance standards for typical Indian conditions. Maintenance strategy and optimization of design will help to foster the technology. The development strategy should give due consideration to the contributions of other countries so as to avoid repetition of work which will save time, money and efforts, and help for the real acceptance of RZTS in Indian conditions.

A smart market for nutrient credit trading to incentivize wetland construction

NASA Astrophysics Data System (ADS)

Raffensperger, John F.; Prabodanie, R. A. Ranga; Kostel, Jill A.

2017-03-01

Nutrient trading and constructed wetlands are widely discussed solutions to reduce nutrient pollution. Nutrient markets usually include agricultural nonpoint sources and municipal and industrial point sources, but these markets rarely include investors who construct wetlands to sell nutrient reduction credits. We propose a new market design for trading nutrient credits, with both point source and non-point source traders, explicitly incorporating the option of landowners to build nutrient removal wetlands. The proposed trading program is designed as a smart market with centralized clearing, done with an optimization. The market design addresses the varying impacts of runoff over space and time, and the lumpiness of wetland investments. We simulated the market for the Big Bureau Creek watershed in north-central Illinois. We found that the proposed smart market would incentivize wetland construction by assuring reasonable payments for the ecosystem services provided. The proposed market mechanism selects wetland locations strategically taking into account both the cost and nutrient removal efficiencies. The centralized market produces locational prices that would incentivize farmers to reduce nutrients, which is voluntary. As we illustrate, wetland builders' participation in nutrient trading would enable the point sources and environmental organizations to buy low cost nutrient credits.

Maintaining adequate nutrient supply - Principles, decision-support tools, and best management practices [Chapter 6

Treesearch

Robert B. Harrison; Douglas A. Maguire; Deborah Page-Dumroese

2011-01-01

Maintaining adequate nutrient supply to maintain or enhance tree vigor and forest growth requires conservation of topsoil and soil organic matter. Sometimes nutrient amendments are also required to supplement inherent nutrient-pool limitations or replenish nutrients removed in harvested material. The goal is to maintain the productive potential of the soil and, when...

Seed removal by scatter-hoarding rodents: the effects of tannin and nutrient concentration.

PubMed

Wang, Bo; Yang, Xiaolan

2015-04-01

The mutualistic interaction between scatter-hoarding rodents and seed plants have a long co-evolutionary history. Plants are believed to have evolved traits that influence the foraging behavior of rodents, thus increasing the probability of seed removal and caching, which benefits the establishment of seedlings. Tannin and nutrient content in seeds are considered among the most essential factors in this plant-animal interaction. However, most previous studies used different species of plant seeds, rendering it difficult to tease apart the relative effect of each single nutrient on rodent foraging behavior due to confounding combinations of nutrient contents across seed species. Hence, to further explore how tannin and different nutritional traits of seed affect scatter-hoarding rodent foraging preferences, we manipulated tannin, fat, protein and starch content levels, and also seed size levels by using an artificial seed system. Our results showed that both tannin and various nutrients significantly affected rodent foraging preferences, but were also strongly affected by seed size. In general, rodents preferred to remove seeds with less tannin. Fat addition could counteract the negative effect of tannin on seed removal by rodents, while the effect of protein addition was weaker. Starch by itself had no effect, but it interacted with tannin in a complex way. Our findings shed light on the effects of tannin and nutrient content on seed removal by scatter-hoarding rodents. We therefore, believe that these and perhaps other seed traits should interactively influence this important plant-rodent interaction. However, how selection operates on seed traits to counterbalance these competing interests/factors merits further study. Copyright © 2015 Elsevier B.V. All rights reserved.

Synergistic effects and optimization of nitrogen and phosphorus concentrations on the growth and nutrient uptake of a freshwater Chlorella vulgaris.

PubMed

Alketife, Ahmed M; Judd, Simon; Znad, Hussein

2017-01-01

The synergistic effects and optimization of nitrogen (N) and phosphorus (P) concentrations on the growth of Chlorella vulgaris (CCAP 211/11B, CS-42) and nutrient removal have been investigated under different concentrations of N (0-56 mg/L) and P (0-19 mg/L). The study showed that N/P ratio has a crucial effect on the biomass growth and nutrient removal. When N/P=10, a complete P and N removal was achieved at the end of cultivation with specific growth rate (SGR) of 1 d -1 and biomass concentration of 1.58 g/L. It was also observed that when the N content <2.5 mg/L, the SGR significantly reduced from 1.04 to 0.23 d -1 and the maximum biomass produced was decreased more than three-fold to 0.5 g/L. The Box-Behnken experimental design and response surface method were used to study the effects of the initial concentrations (P, N and C) on P and N removal efficiencies. The optimized P, N and C concentrations supporting 100% removal of both P and N at an SGR of 0.95 were 7, 55 and 10 mg/L respectively, with desirability value of 0.94. The results and analysis obtained could be very useful when applying the microalgae for efficient wastewater treatment and nutrient removal.

Fate and effects of nitrogen and phosphorus in shallow vegetated aquatic ecosystems

USGS Publications Warehouse

Fairchild, James F.; Vradenburg, Leigh Ann

2006-01-01

Nitrate concentrations have greatly increased in streams and rivers draining agricultural regions of the Midwestern United States, increasing nitrate transport to the Gulf of Mexico has been implicated in the hypoxic conditions that threaten the productivity of marine fisheries. Increases in nitrate concentrations have been attributed to a combination of factors including agricultural expansion, increased nitrogen application rates, increased tile drainage, and loss of riparian Wetlands, These landscape-level changes have resulted in a decreased natural capacity for nitrogen uptake, removal, and cycling back to the atmosphere. Land managers are increasingly interested in using wetland construction and rehabilitation as a management practice to reduce loss of nitrate from the terrestrial systems. Yet, relatively little is known about the limnological factors involved in nitrate removal by Wetland systems.We conducted a series of studies from 1999-2000 to investigate the functional capacity of shallow, macrophyte-dominated pond wetland systems for uptake, assimilation, and retention of nitrogen (N) and phosphorus (P). We evaluated four factors that were hypothesized to influence nutrient uptake and assimilation: 1) nitrate loading rates; 2) nitrogen to phosphorus (N.P) ratios; 3) frequency of dosing/application; and 4) timing of dose initiation.Nutrient assimilation was rapid; store than 90% of added nutrients were removed from the water column in all treatments. Neither variation in N:P ratios (evaluated range, <13:1 to -114.1), frequency of application (weekly or bi-weekly), nor liming of dose initiation relative to macrophyte development (0%, 15-25%, or 75-90% maximum biomass) had significant effects on nutrient assimilation of wetland community dynamics. Maximum loading of nitrate (60 g N/m2 2.4 g P/m2) applied as six weekly doses stimulated algal communities, but inhibited macrophyte communities.Predicted shifts from a stable state of macrophyte- to phytoplankton-dominance did not occur due to nutrient additions. Macrophytes, phytoplankton, and the sediment surface were all significant factors in the removal of nitrate from the Water column. Overall, these shallow macrophyte-dominated systems provided an efficient means of removing nutrients from the water column. Construction or rehabilitation of shallow, vegetated wetlands may offer promise as land management practices for nutrient removal in agricultural watersheds.

Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin.

PubMed

O'Reilly, Andrew M; Wanielista, Martin P; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G

2012-08-15

Soil beneath a stormwater infiltration basin receiving runoff from a 23 ha predominantly residential watershed in north-central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop an innovative stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO(3)(-)/Cl(-)) ratios for the shallow groundwater indicates that prior to using BAM, NO(3)(-) concentrations were substantially influenced by nitrification or variations in NO(3)(-) input. In contrast, for the new basin utilizing BAM, NO(3)(-)/Cl(-) ratios indicate minor nitrification and NO(3)(-) losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest that NO(3)(-) losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by the increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO(4)(3-)) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO(4)(3-)/Cl(-) ratios for shallow groundwater indicate predominantly minor increases and decreases in PO(4)(3-) with the exception of one summer sample that indicated a 50% loss. Differences in nutrient variations between the unsaturated zone and shallow groundwater may be the result of the intensity and duration of nutrient removal processes and mixing ratios with water that had undergone little biogeochemical transformation. Observed nitrogen and phosphorus losses demonstrate the potential, as well as the future research needs to improve performance, of the innovative stormwater infiltration basin using BAM for providing passive, economical, stormwater nutrient-treatment technology to support green infrastructure. Copyright © 2012 Elsevier B.V. All rights reserved.

Biological Hydrogen Production: Simultaneous Saccharification and Fermentation With Nitrogen and Phosphorus Removal from Wastewater Effluent

DTIC Science & Technology

2010-01-01

requiring thermochemical pretreatment , aswould typically be required with lignocellulosic feedstocks. Therefore it offers a readily-processed and...Standards and Technology. The pH of the reactors was controlled throughout all fermentations by the automatic addition of 0.1 N NaOH . Total organic...nutrients. The optimized conditions developed with paper as a substrate may also convey to the use of a similar process with lignocellulosic biomass

Treatment of high ethanol concentration wastewater by biological sand filters: enhanced COD removal and bacterial community dynamics.

PubMed

Rodriguez-Caballero, A; Ramond, J-B; Welz, P J; Cowan, D A; Odlare, M; Burton, S G

2012-10-30

Winery wastewater is characterized by its high chemical oxygen demand (COD), seasonal occurrence and variable composition, including periodic high ethanol concentrations. In addition, winery wastewater may contain insufficient inorganic nutrients for optimal biodegradation of organic constituents. Two pilot-scale biological sand filters (BSFs) were used to treat artificial wastewater: the first was amended with ethanol and the second with ethanol, inorganic nitrogen (N) and phosphorus (P). A number of biochemical parameters involved in the removal of pollutants through BSF systems were monitored, including effluent chemistry and bacterial community structures. The nutrient supplemented BSF showed efficient COD, N and P removal. Comparison of the COD removal efficiencies of the two BSFs showed that N and P addition enhanced COD removal efficiency by up to 16%. Molecular fingerprinting of BSF sediment samples using denaturing gradient gel electrophoresis (DGGE) showed that amendment with high concentrations of ethanol destabilized the microbial community structure, but that nutrient supplementation countered this effect. Copyright © 2012 Elsevier Ltd. All rights reserved.

How the distribution of anthropogenic nitrogen has changed in Narragansett Bay (RI, USA) following major reductions in nutrient loads

EPA Science Inventory

Over the past decade, nitrogen (N) loads to Narragansett Bay have decreased by about 65%. These reductions were the direct result of multiple sewage treatment plant upgrades to tertiary treatment, a process which employs N removal. Here we document ecosystem response to the N red...

21 CFR 101.91 - Gluten-free labeling of food.

Code of Federal Regulations, 2014 CFR

2014-04-01

... that has not been processed to remove gluten (e.g., wheat flour); or (3) An ingredient that is derived... is below 20 ppm gluten (i.e., below 20 mg gluten per kg of food). (b) Requirements. (1) A food that... Nutrient Content Claims nor Health Claims § 101.91 Gluten-free labeling of food. (a) Definitions. (1) The...

Internal cycling, not external loading, decides the nutrient limitation in eutrophic lake: A dynamic model with temporal Bayesian hierarchical inference.

PubMed

Wu, Zhen; Liu, Yong; Liang, Zhongyao; Wu, Sifeng; Guo, Huaicheng

2017-06-01

Lake eutrophication is associated with excessive anthropogenic nutrients (mainly nitrogen (N) and phosphorus (P)) and unobserved internal nutrient cycling. Despite the advances in understanding the role of external loadings, the contribution of internal nutrient cycling is still an open question. A dynamic mass-balance model was developed to simulate and measure the contributions of internal cycling and external loading. It was based on the temporal Bayesian Hierarchical Framework (BHM), where we explored the seasonal patterns in the dynamics of nutrient cycling processes and the limitation of N and P on phytoplankton growth in hyper-eutrophic Lake Dianchi, China. The dynamic patterns of the five state variables (Chla, TP, ammonia, nitrate and organic N) were simulated based on the model. Five parameters (algae growth rate, sediment exchange rate of N and P, nitrification rate and denitrification rate) were estimated based on BHM. The model provided a good fit to observations. Our model results highlighted the role of internal cycling of N and P in Lake Dianchi. The internal cycling processes contributed more than external loading to the N and P changes in the water column. Further insights into the nutrient limitation analysis indicated that the sediment exchange of P determined the P limitation. Allowing for the contribution of denitrification to N removal, N was the more limiting nutrient in most of the time, however, P was the more important nutrient for eutrophication management. For Lake Dianchi, it would not be possible to recover solely by reducing the external watershed nutrient load; the mechanisms of internal cycling should also be considered as an approach to inhibit the release of sediments and to enhance denitrification. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in hyperspectral reflectance signatures of lettuce leaves in response to macronutrient deficiencies

NASA Astrophysics Data System (ADS)

Pacumbaba, R. O.; Beyl, C. A.

2011-07-01

The adaptation of specific remote sensing and hyperspectral analysis techniques for the determination of incipient nutrient stress in plants could allow early detection and precision supplementation for remediation, important considerations for minimizing mass of advanced life support systems on space station and long term missions. This experiment was conducted to determine if hyperspectral reflectance could be used to detect nutrient stress in Lactuca sativa L. cv. Black Seeded Simpson. Lettuce seedlings were grown for 90 days in a greenhouse or growth chamber in vermiculite containing modified Hoagland's nutrient solution with key macronutrient elements removed in order to induce a range of nutrient stresses, including nitrogen, phosphorus, potassium, calcium, and magnesium. Leaf tissue nutrient concentrations were compared with corresponding spectral reflectances taken at the end of 90 days. Spectral reflectances varied with growing location, position on the leaf, and nutrient deficiency treatment. Spectral responses of lettuce leaves under macronutrient deficiency conditions showed an increase in reflectance in the red, near red, and infrared wavelength ranges. The data obtained suggest that spectral reflectance shows the potential as a diagnostic tool in predicting nutrient deficiencies in general. Overlapping of spectral signatures makes the use of wavelengths of narrow bandwidths or individual bands for the discrimination of specific nutrient stresses difficult without further data processing.

Innovative low cost procedure for nutrient removal as an integrated element of a decentralised water management concept for rural areas.

PubMed

Burde, M; Rolf, F; Grabowski, F

2001-01-01

The absence of large rivers with rather high niveau of self purifying effect in parts of east Germany leads to a discharging of the effluent of wastewater treatment plants into the groundwater in many cases. One useful consequence is the idea of realisation of decentralised measures and concepts in urban water resources management concerning municipal wastewater as well as rainfall, precipitation. At the same time, only the upper soil zone--a few decimetres--is water--saturated and thus discharge effective, even when extreme rainfall takes place. Underneath, however, there generally exists an unsaturated soil zone, which is up to now a rather unexplored retardation element of the hydrologic- and substrate-cycle. Nutrient removal in small wastewater treatment plants that are emptying into ground waters is often beneficial. The presented studies optimised an inexpensive method of subsequent enhanced wastewater treatment. The developed reactor is similar to a concentrated subsoil passage. The fixed bed reactor is divided in two sections to achieve aerobic and anoxic conditions for nitrification/denitrification processes. To enhance phosphorus removal, ferrous particles are put into the aerobic zone. Two series of column tests were carried out and a technical pilot plant was built to verify the efficiency of the process. The results show that this method can be implemented successfully.

Life cycle assessment of nutrient removal technologies for the treatment of anaerobic digestion supernatant and its integration in a wastewater treatment plant.

PubMed

Rodriguez-Garcia, G; Frison, N; Vázquez-Padín, J R; Hospido, A; Garrido, J M; Fatone, F; Bolzonella, D; Moreira, M T; Feijoo, G

2014-08-15

The supernatant resulting from the anaerobic digestion of sludge generated by wastewater treatment plants (WWTP) is an attractive flow for technologies such as partial nitritation-anammox (CANON), nitrite shortcut (NSC) and struvite crystallization processes (SCP). The high concentration of N and P and its low flow rate facilitate the removal of nutrients under more favorable conditions than in the main water line. Despite their operational and economic benefits, the environmental burdens of these technologies also need to be assessed to prove their feasibility under a more holistic perspective. The potential environmental implications of these technologies were assessed using life cycle assessment, first at pilot plant scale, later integrating them in a modeled full WWTP. Pilot plant results reported a much lower environmental impact for N removal technologies than SCP. Full-scale modeling, however, highlighted that the differences between technologies were not relevant once they are integrated in a WWTP. The impacts associated with the WWTP are slightly reduced in all categories except for eutrophication, where a substantial reduction was achieved using NSC, SCP, and especially when CANON and SCP were combined. This study emphasizes the need for assessing wastewater treatment technologies as part of a WWTP rather than as individual processes and the utility of modeling tools for doing so. Copyright © 2014 Elsevier B.V. All rights reserved.

Balancing carbon/nitrogen ratio to improve nutrients removal and algal biomass production in piggery and brewery wastewaters.

PubMed

Zheng, Hongli; Liu, Mingzhi; Lu, Qian; Wu, Xiaodan; Ma, Yiwei; Cheng, Yanling; Addy, Min; Liu, Yuhuan; Ruan, Roger

2018-02-01

To improve nutrients removal from wastewaters and enhance algal biomass production, piggery wastewater was mixed with brewery wastewaters. The results showed that it was a promising way to cultivate microalga in piggery and brewery wastewaters by balancing the carbon/nitrogen ratio. The optimal treatment condition for the mixed piggery-brewery wastewater using microalga was piggery wastewater mixed with brewery packaging wastewater by 1:5 at pH 7.0, resulting in carbon/nitrogen ratio of 7.9, with the biomass concentration of 2.85 g L -1 , and the removal of 100% ammonia, 96% of total nitrogen, 90% of total phosphorus, and 93% of chemical oxygen demand. The application of the established strategies can enhance nutrient removal efficiency of the wastewaters while reducing microalgal biomass production costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluating topsoil depth effects on phosphorus and potassium nutrient dynamics of grain and switchgrass production systems

USDA-ARS?s Scientific Manuscript database

Understanding the effects of fertilizer addition and crop removal on long-term change in soil test phosphorus (STP) and soil test potassium (STK) is crucial for maximizing the use of grower inputs on claypan soils. Due to variable nutrient supply from subsoils and variable crop removal across fields...

Aquatic macrophytes can be used for wastewater polishing but not for purification in constructed wetlands

NASA Astrophysics Data System (ADS)

Tang, Yingying; Harpenslager, Sarah F.; van Kempen, Monique M. L.; Verbaarschot, Evi J. H.; Loeffen, Laury M. J. M.; Roelofs, Jan G. M.; Smolders, Alfons J. P.; Lamers, Leon P. M.

2017-02-01

The sequestration of nutrients from surface waters by aquatic macrophytes and sediments provides an important service to both natural and constructed wetlands. While emergent species take up nutrients from the sediment, submerged and floating macrophytes filter nutrients directly from the surface water, which may be more efficient in constructed wetlands. It remains unclear, however, whether their efficiency is sufficient for wastewater purification and how plant species and nutrient loading affects nutrient distribution over plants, water and sediment. We therefore determined nutrient removal efficiencies of different vegetation (Azolla filiculoides, Ceratophyllum demersum and Myriophyllum spicatum) and sediment types (clay, peaty clay and peat) at three nutrient input rates, in a full factorial, outdoor mesocosm experiment. At low loading (0.43 mg P m-2 d-1), plant uptake was the main pathway (100 %) for phosphorus (P) removal, while sediments showed a net P release. A. filiculoides and M. spicatum showed the highest biomass production and could be harvested regularly for nutrient recycling, whereas C. demersum was outcompeted by spontaneously developing macrophytes and algae. Higher nutrient loading only stimulated A. filiculoides growth. At higher rates ( ≥ 21.4 mg P m-2 d-1), 50-90 % of added P ended up in sediments, with peat sediments becoming more easily saturated. For nitrogen (N), 45-90 % was either taken up by the sediment or lost to the atmosphere at loadings ≥ 62 mg N m-2 d-1. This shows that aquatic macrophytes can indeed function as an efficient nutrient filter but only for low loading rates (polishing) and not for high rates (purification). The outcome of this controlled study not only contributes to our understanding of nutrient dynamics in constructed wetlands but also shows the differential effects of wetland sediment types and plant species. Furthermore, the acquired knowledge may benefit the application of macrophyte harvesting to remove and recycle nutrients from both constructed wetlands and nutrient-loaded natural wetlands.

Environmental and biogeochemical changes following a decade's reclamation in the Dapeng (Tapong) Bay, southwestern Taiwan

NASA Astrophysics Data System (ADS)

Hung, J.-J.; Huang, W.-C.; Yu, C.-S.

2013-09-01

This study examines the environmental and biogeochemical changes in Dapeng (formerly spelled Tapong) Bay, a semi-enclosed coastal lagoon in southwestern Taiwan, after two major reclamation works performed between 1999 and 2010. The lagoon was largely occupied by oyster culture racks and fish farming cages before December, 2002. Substantial external inputs of nutrients and organic carbon and the fairly long water exchange time (τ) (10 ± 2 days) caused the lagoon to enter a eutrophic state, particularly at the inner lagoon, which directly received nutrient inputs. However, the entire lagoon showed autotrophic, and the estimated net ecosystem production (NEP) during the first stage was 5.8 mol C m-2 yr-1. After January, 2003, the aquaculture structures were completely removed, and the τ decreased to 6 ± 2 days. The annual mean concentrations of dissolved oxygen increased, and nutrients decreased substantially, likely due to improved water exchange, absence of feeding and increased biological utilization. The NEP increased 37% to 7.7 mol C m-2 yr-1 after structure removal. The second reclamation work beginning from July, 2006, focused on establishing artificial wetlands for wastewater treatment and on dredging bottom sediment. Although the τ did not change significantly (8 ± 3 days), substantial decreases in nutrient concentrations and dissolved organic matter continued. The NEP (14.3 mol C m-2 yr-1) increased 85% compared to that in the second stage. The data suggest that the reclamations substantially improved water quality, carbon and nutrient biogeochemical processes and budgets in this semi-enclosed ecosystem.

The effects of nutrient solution sterilization on the growth and yield of hydroponically grown lettuce

NASA Technical Reports Server (NTRS)

Schwartzkopf, S. H.; Dudzinski, D.; Minners, R. S.

1987-01-01

Two methods of removing bacteria from hydroponic nutrient solution [ultraviolet (UV) radiation and submicronic filter] were evaluated for efficiency and for their effects on lettuce (Lactuca sativa L.) production. Both methods were effective in removing bacteria; but, at high intensity, the ultraviolet sterilizer significantly inhibited the production of plants grown in the treated solution. Bacterial removal by lower intensity UV or a submicronic filter seemed to promote plant growth slightly, but showed no consistent, statistically significant effect.

Electrodialytic 2-compartment cells for emerging organic contaminants removal from effluent.

PubMed

Ferreira, Ana Rita; Couto, Nazaré; Guedes, Paula; Pinto, Joana; Mateus, Eduardo P; Ribeiro, Alexandra B

2018-04-27

The present work discusses the efficiency of the electrodialytic (ED) process to remove emerging organic contaminants (EOCs) from effluent. The ED process was carried out in a cell of two-compartments (2 C-cell) with effluent in either the anode or cathode compartment, separated from the electrolyte compartment through an anion or a cation exchange membrane (AEM and CEM, respectively). As effluent destination might be soil irrigation, and having in mind the nutrient recycling, phosphorus was also monitored in the process. The ED removals showed to be dependent of EOCs characteristics and cell design. Removals were higher when using an AEM (60-72%) than a CEM (8-63%), except for caffeine when the effluent was placed in the cathode, that did not show any removal. When using an AEM with the effluent placed in the anode compartment, all the EOCs (including caffeine) were removed between 57-72%, mainly through electrodegradation phenomena. Regarding phosphorus, a polarity switch may be done to a 2 C-cell with a AEM, depending on the effluent final use. This technology is still in its first steps and, in both cases, further optimization of ED parameters is needed. Still, this technological innovation and cross-cutting research envisages the promotion of economic, social and environmental benefits. Copyright © 2018 Elsevier B.V. All rights reserved.

Nutrient and dissolved organic carbon removal from natural waters using industrial by-products.

PubMed

Wendling, Laura A; Douglas, Grant B; Coleman, Shandel; Yuan, Zheng

2013-01-01

Attenuation of excess nutrients in wastewater and stormwater is required to safeguard aquatic ecosystems. The use of low-cost, mineral-based industrial by-products with high Ca, Mg, Fe or Al content as a solid phase in constructed wetlands potentially offers a cost-effective wastewater treatment option in areas without centralised water treatment facilities. Our objective was to investigate use of water treatment residuals (WTRs), coal fly ash (CFA), and granular activated carbon (GAC) from biomass combustion in in-situ water treatment schemes to manage dissolved organic carbon (DOC) and nutrients. Both CaO- and CaCO(3)-based WTRs effectively attenuated inorganic N species but exhibited little capacity for organic N removal. The CaO-based WTR demonstrated effective attenuation of DOC and P in column trials, and a high capacity for P sorption in batch experiments. Granular activated carbon proved effective for DOC and dissolved organic nitrogen (DON) removal in column trials, but was ineffective for P attenuation. Only CFA demonstrated effective removal of a broad suite of inorganic and organic nutrients and DOC; however, Se concentrations in column effluents exceeded Australian and New Zealand water quality guideline values. Water treated by filtering through the CaO-based WTR exhibited nutrient ratios characteristic of potential P-limitation with no potential N- or Si-limitation respective to growth of aquatic biota, indicating that treatment of nutrient-rich water using the CaO-based WTR may result in conditions less favourable for cyanobacterial growth and more favourable for growth of diatoms. Results show that selected industrial by-products may mitigate eutrophication through targeted use in nutrient intervention schemes. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Evaluating nitrogen removal by vegetation uptake using satellite image time series in riparian catchments.

PubMed

Wang, Xuelei; Wang, Qiao; Yang, Shengtian; Zheng, Donghai; Wu, Chuanqing; Mannaerts, C M

2011-06-01

Nitrogen (N) removal by vegetation uptake is one of the most important functions of riparian buffer zones in preventing non-point source pollution (NSP), and many studies about N uptake at the river reach scale have proven the effectiveness of plants in controlling nutrient pollution. However, at the watershed level, the riparian zones form dendritic networks and, as such, may be the predominant spatially structured feature in catchments and landscapes. Thus, assessing the functions of riparian system at the basin scale is important. In this study, a new method coupling remote sensing and ecological models was used to assess the N removal by riparian vegetation on a large spatial scale. The study site is located around the Guanting reservoir in Beijing, China, which was abandoned as the source water system for Beijing due to serious NSP in 1997. SPOT 5 data was used to map the land cover, and Landsat-5 TM time series images were used to retrieve land surface parameters. A modified forest nutrient cycling and biomass model (ForNBM) was used to simulate N removal, and the modified net primary productivity (NPP) module was driven by remote sensing image time series. Besides the remote sensing data, the necessary database included meteorological data, soil chemical and physical data and plant nutrient data. Pot and plot experiments were used to calibrate and validate the simulations. Our study has proven that, by coupling remote sensing data and parameters retrieval techniques to plant growth process models, catchment scale estimations of nitrogen uptake rates can be improved by spatial pixel-based modelling. Copyright © 2011 Elsevier B.V. All rights reserved.

Recovery and removal of nutrients from swine wastewater by using a novel integrated reactor for struvite decomposition and recycling

PubMed Central

Huang, Haiming; Xiao, Dean; Liu, Jiahui; Hou, Li; Ding, Li

2015-01-01

In the present study, struvite decomposition was performed by air stripping for ammonia release and a novel integrated reactor was designed for the simultaneous removal and recovery of total ammonia-nitrogen (TAN) and total orthophosphate (PT) from swine wastewater by internal struvite recycling. Decomposition of struvite by air stripping was found to be feasible. Without supplementation with additional magnesium and phosphate sources, the removal ratio of TAN from synthetic wastewater was maintained at >80% by recycling of the struvite decomposition product formed under optimal conditions, six times. Continuous operation of the integrated reactor indicated that approximately 91% TAN and 97% PT in the swine wastewater could be removed and recovered by the proposed recycling process with the supplementation of bittern. Economic evaluation of the proposed system showed that struvite precipitation cost can be saved by approximately 54% by adopting the proposed recycling process in comparison with no recycling method. PMID:25960246

Speciation and fate of copper in sewage treatment works with and without tertiary treatment: the effect of return flows.

PubMed

Innaa, D; Lester, J N; Scrimshawb, M D; Cartmell, E

2014-01-01

The removal of metals from wastewaters is becoming an important issue, with new environmental quality standards putting increased regulatory pressure on operators of sewage treatment works. The use of additional processes (tertiary treatment) following two-stage biological treatment is frequently seen as a way of improving effluent quality for nutrients and suspended solids, and this study investigates the impact of how back washes from these tertiary processes may impact the removal of copper during primary sedimentation. Seven sites were studied, three conventional two-stage biological treatment, and four with tertiary processes. It was apparent that fluxes of copper in traditional return flows made a significant contribution to the load to the primary treatment tanks, and that <1% of this was in the dissolved phase. Where tertiary processes were used, back wash liquors were also returned to the primary tanks. These return flows had an impact on copper removal in the primary tanks, probably due to their aerobic nature. Returning such aerobic back wash flows to the main process stream after primary treatment may therefore be worth consideration. The opportunity to treat consolidated liquor and sludge.flows in side-stream processes to remove toxic elements, as they are relatively concentrated, low volume flow streams, should also be evaluated.

Mixtures of macrophyte growth forms promote nitrogen cycling in wetlands.

PubMed

Choudhury, Maidul I; McKie, Brendan G; Hallin, Sara; Ecke, Frauke

2018-09-01

The importance of aquatic plant diversity in regulating nutrient cycling in wetlands remains poorly understood. We investigated how variation in macrophyte growth form (emerging, submerged and bryophyte) combinations and species mixtures affect nitrogen (N) removal from the water and N accumulation in plant biomass. We conducted a wetland mesocosm experiment for 100 days during July-September 2015. Twelve species were grown in mono- and in two-species mixed cultures for a total of 32 single and two-growth form combinations. Nitrogen removal from the water was quantified on three occasions during the experiment, while N accumulation in plant biomass was determined following termination of the experiment. The number of species and growth forms present increased N removal and accumulation. The growth form combinations of emerging and bryophyte species showed the highest N accumulation and N removal from water, followed by combinations of emerging species. By contrast, submerged species growing in the presence of emerging or other submerged species showed the lowest levels of N accumulation and N removal. Temporal variation in N removal also differed among growth form combinations: N removal was highest for emerging-bryophyte combinations in July, but peaked for the emerging-submerged and emerging-bryophyte combinations in August. Indeed, the occurrence of complementarity among macrophyte species, particularly in combinations of bryophyte and emerging species, enhanced N removal and uptake during the entire growing season. Our study highlights the importance of bryophytes, which have been neglected in research on nutrient cycling in wetlands, for aquatic N cycling, especially given their worldwide distribution across biomes. Overall, our findings point towards the potential important role of the diversity of macrophyte growth forms in regulating key ecosystem processes related to N cycling in wetlands. Copyright © 2018 Elsevier B.V. All rights reserved.

High-strength fermentable wastewater reclamation through a sequential process of anaerobic fermentation followed by microalgae cultivation.

PubMed

Qi, Wenqiang; Chen, Taojing; Wang, Liang; Wu, Minghong; Zhao, Quanyu; Wei, Wei

2017-03-01

In this study, the sequential process of anaerobic fermentation followed by microalgae cultivation was evaluated from both nutrient and energy recovery standpoints. The effects of different fermentation type on the biogas generation, broth metabolites' composition, algal growth and nutrients' utilization, and energy conversion efficiencies for the whole processes were discussed. When the fermentation was designed to produce hydrogen-dominating biogas, the total energy conversion efficiency (TECE) of the sequential process was higher than that of the methane fermentation one. With the production of hydrogen in anaerobic fermentation, more organic carbon metabolites were left in the broth to support better algal growth with more efficient incorporation of ammonia nitrogen. By applying the sequential process, the heat value conversion efficiency (HVCE) for the wastewater could reach 41.2%, if methane was avoided in the fermentation biogas. The removal efficiencies of organic metabolites and NH 4 + -N in the better case were 100% and 98.3%, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

The under sink garbage grinder: a friendly technology for the environment.

PubMed

Bolzonella, D; Pavan, P; Battistoni, P; Cecchi, F

2003-03-01

The use of garbage grinders is not a usual practice in Europe, but it is in other countries around the world (e.g., North America, Japan and Australia). Sometimes, garbage grinders are accused of producing problems in sewers and wastewater treatment plants and are prohibited by environmental protection laws. In this study, the different impacts determined by the use of this technology were considered to show the positive impacts of its use. In particular, it was shown that garbage grinders enable the disposal of household organic wastes with advantages for the wastewater treatment processes because of an increase in the carbon/nutrients ratio in the wastewater. This is particularly important for biological nutrients removal processes. Daily specific contributions for person equivalent (PE) due to organic waste disposal through garbage grinders were found to be equal to 75 gCODPE(-1) d(-1) for carbon (as COD), 2.5 gNPE(-1) d(-1) for nitrogen and 0.25 gPPE(-1) d(-1) for phosphorous, respectively. Those determined a value of 30 for the COD/N ratio. Moreover, no problems with solids settling in sewers were noted. These results were extensively compared with literature data. The economical balance showed that the use of garbage grinders allowed a global saving of some 17 Euro year(-1) for a three people family. Important benefits are also gained from an environmental point of view (e.g, organic wastes disposal nutrients removal in wastewater treatment and increase in biogas production with energy reclamation).

Multiyear nutrient removal performance of three constructed wetlands intercepting tile drain flows from grazed pastures.

PubMed

Tanner, Chris C; Sukias, James P S

2011-01-01

Subsurface tile drain flows can be a major s ource of nurient loss from agricultural landscapes. This study quantifies flows and nitrogen and phosphorus yields from tile drains at three intensively grazed dairy pasture sites over 3- to 5-yr periods and evaluates the capacity of constructed wetlands occupying 0.66 to 1.6% of the drained catchments too reduce nutrient loads. Continuous flow records are combined with automated flow-proportional sampling of nutrient concentrations to calculate tile drain nutrient yields and wetland mass removal rates. Annual drainage water yields rangedfrom 193 to 564 mm (16-51% of rainfall) at two rain-fed sites and from 827 to 853 mm (43-51% of rainfall + irrigation) at an irrigated site. Annually, the tile drains exported 14 to 109 kg ha(-1) of total N (TN), of which 58 to 90% was nitrate-N. Constructed wetlands intercepting these flows removed 30 to 369 gTN m(-2) (7-63%) of influent loadings annually. Seasonal percentage nitrate-N and TN removal were negatively associated with wetland N mass loadings. Wetland P removal was poor in all wetlands, with 12 to 115% more total P exported annually overall than received. Annually, the tile drains exported 0.12 to 1.38 kg ha of total P, of which 15 to 93% was dissolved reactive P. Additional measures are required to reduce these losses or provide supplementary P removal. Wetland N removal performance could be improved by modifying drainage systems to release flows more gradually and improving irrigation practices to reduce drainage losses.

Assessing nutrient flows in septic tanks by eliciting expert judgement: a promising method in the context of developing countries.

PubMed

Montangero, Agnes; Belevi, Hasan

2007-03-01

Simple models based on the physical and biochemical processes occurring in septic tanks, pit and urine diversion latrines were developed to determine the nutrient flows in these systems. Nitrogen and phosphorus separation in different output materials from these on-site sanitation installations were thus determined. Moreover, nutrient separation in septic tanks was also assessed through literature values and by eliciting expert judgement. Use of formal expert elicitation technique proved to be effective, particularly in the context of developing countries where data is often scarce but expert judgement readily available. In Vietnam, only 5-14% and 11-27% of the nitrogen and phosphorus input, respectively, are removed from septic tanks with the faecal sludge. The remaining fraction leaves the tank via the liquid effluent. Unlike septic tanks, urine diversion latrines allow to immobilize most of the nutrients either in form of stored urine or dehydrated faecal matter. These latrines thus contribute to reducing the nutrient load in the environment and lowering consumption of energy and non-renewable resources for fertiliser production.

Effect of nutrients on the biodegradation of tributyltin (TBT) by alginate immobilized microalga, Chlorella vulgaris, in natural river water.

PubMed

Jin, Jing; Yang, Lihua; Chan, Sidney M N; Luan, Tiangang; Li, Yan; Tam, Nora F Y

2011-01-30

The removal and degradation of tributyltin (TBT) by alginate immobilized Chlorella vulgaris has been evidenced in our previously published work. The present study was further to investigate the effect of spiked nutrient concentrations on the TBT removal capacity and degradation in the same alginate immobilized C. vulgaris. During the 14-d experiment, compared to the control (natural river water), the spiked nutrient groups (50% or 100% nutrients of the commercial Bristol medium as the reference, marked as 1/2N or 1N) showed more rapid cell proliferation of microalgae and higher TBT removal rate. Moreover, significantly more TBT was adsorbed onto the alginate matrix, but less TBT was taken up by the algal cells of the nutrient groups than that of the control. Mass balance data showed that TBT was lost as inorganic tin in the highest degree in 1N group, followed by 1/2N group and the least was in the control, but the relative abundance of the intermediate products of debutylation (dibutyltin and monobutyltin) were comparable among three groups. In conclusion, the addition of nutrients in contaminated water stimulated the growth and physiological activity of C. vulgaris immobilized in alginate beads and improved its TBT degradation efficiency. Copyright © 2010 Elsevier B.V. All rights reserved.

Guava Waste to Sustain Guava (Psidium guajava) Agroecosystem: Nutrient "Balance" Concepts.

PubMed

Souza, Henrique A; Parent, Serge-Étienne; Rozane, Danilo E; Amorim, Daniel A; Modesto, Viviane C; Natale, William; Parent, Leon E

2016-01-01

The Brazilian guava processing industry generates 5.5 M Mg guava waste year(-1) that could be recycled sustainably in guava agro-ecosystems as slow-release fertilizer. Our objectives were to elaborate nutrient budgets and to diagnose soil, foliar, and fruit nutrient balances in guava orchards fertilized with guava waste. We hypothesized that (1) guava waste are balanced fertilizer sources that can sustain crop yield and soil nutrient stocks, and (2) guava agroecosystems remain productive within narrow ranges of nutrient balances. A 6-year experiment was conducted in 8-year old guava orchard applying 0-9-18-27-36 Mg ha(-1) guava waste (dry mass basis) and the locally recommended mineral fertilization. Nutrient budgets were compiled as balance sheets. Foliar and fruit nutrient balances were computed as isometric log ratios to avoid data redundancy or resonance due to nutrient interactions and the closure to measurement unit. The N, P, and several other nutrients were applied in excess of crop removal while K was in deficit whatever the guava waste treatment. The foliar diagnostic accuracy reached 93% using isometric log ratios and knn classification, generating reliable foliar nutrient and concentration ranges at high yield level. The plant mined the soil K reserves without any significant effect on fruit yield and foliar nutrient balances involving K. High guava productivity can be reached at lower soil test K and P values than thought before. Parsimonious dosage of fresh guava waste should be supplemented with mineral K fertilizers to recycle guava waste sustainably in guava agroecosystems. Brazilian growers can benefit from this research by lowering soil test P and K threshold values to avoid over-fertilization and using fresh guava waste supplemented with mineral fertilizers, especially K. Because yield was negatively correlated with fruit acidity and Brix index, balanced plant nutrition and fertilization diagnosis will have to consider not only fruit yield targets but also fruit quality to meet requirements for guava processing.

Guava Waste to Sustain Guava (Psidium guajava) Agroecosystem: Nutrient “Balance” Concepts

PubMed Central

Souza, Henrique A.; Parent, Serge-Étienne; Rozane, Danilo E.; Amorim, Daniel A.; Modesto, Viviane C.; Natale, William; Parent, Leon E.

2016-01-01

The Brazilian guava processing industry generates 5.5 M Mg guava waste year−1 that could be recycled sustainably in guava agro-ecosystems as slow-release fertilizer. Our objectives were to elaborate nutrient budgets and to diagnose soil, foliar, and fruit nutrient balances in guava orchards fertilized with guava waste. We hypothesized that (1) guava waste are balanced fertilizer sources that can sustain crop yield and soil nutrient stocks, and (2) guava agroecosystems remain productive within narrow ranges of nutrient balances. A 6-year experiment was conducted in 8-year old guava orchard applying 0–9–18–27–36 Mg ha−1 guava waste (dry mass basis) and the locally recommended mineral fertilization. Nutrient budgets were compiled as balance sheets. Foliar and fruit nutrient balances were computed as isometric log ratios to avoid data redundancy or resonance due to nutrient interactions and the closure to measurement unit. The N, P, and several other nutrients were applied in excess of crop removal while K was in deficit whatever the guava waste treatment. The foliar diagnostic accuracy reached 93% using isometric log ratios and knn classification, generating reliable foliar nutrient and concentration ranges at high yield level. The plant mined the soil K reserves without any significant effect on fruit yield and foliar nutrient balances involving K. High guava productivity can be reached at lower soil test K and P values than thought before. Parsimonious dosage of fresh guava waste should be supplemented with mineral K fertilizers to recycle guava waste sustainably in guava agroecosystems. Brazilian growers can benefit from this research by lowering soil test P and K threshold values to avoid over-fertilization and using fresh guava waste supplemented with mineral fertilizers, especially K. Because yield was negatively correlated with fruit acidity and Brix index, balanced plant nutrition and fertilization diagnosis will have to consider not only fruit yield targets but also fruit quality to meet requirements for guava processing. PMID:27621735

Screening of microalgae for integral biogas slurry nutrient removal and biogas upgrading by different microalgae cultivation technology.

PubMed

Wang, Xue; Bao, Keting; Cao, Weixing; Zhao, Yongjun; Hu, Chang Wei

2017-07-14

The microalgae-based technology has been developed to reduce biogas slurry nutrients and upgrade biogas simultaneously. In this work, five microalgal strains named Chlorella vulgaris, Scenedesmus obliquus, Selenastrum capricornutum, Nitzschia palea, and Anabaena spiroides under mono- and co-cultivation were used for biogas upgrading. Optimum biogas slurry nutrient reduction could be achieved by co-cultivating microalgae (Chlorella vulgaris, Scenedesmus obliquus, and Nitzschia palea) with fungi using the pelletization technology. In addition, the effects of different ratio of mixed LED light wavelengths applying mixed light-emitting diode during algae strains and fungi co-cultivation on CO 2 and biogas slurry nutrient removal efficiency were also investigated. The results showed that the COD (chemical oxygen demand), TN (total nitrogen), and TP (total phosphorus) removal efficiency were 85.82 ± 5.37%, 83.31 ± 4.72%, and 84.26 ± 5.58%, respectively at red: blue = 5:5 under the co-cultivation of S. obliquus and fungi. In terms of biogas upgrading, CH 4 contents were higher than 90% (v/v) for all strains, except the co-cultivation with S. obliquus and fungi at red: blue = 3:7. The results indicated that co-cultivation of microalgae with fungi under mixed light wavelengths treatments was most successful in nutrient removal from wastewater and biogas upgrading.

Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants.

PubMed

Tsydenova, Oyuna; Batoev, Valeriy; Batoeva, Agniya

2015-08-14

The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fenton. Complex water matrices with high loads of pathogens and chemical pollutants negatively affect the efficiency of disinfection and pollutant removal. This is due to competition between chemical substances and pathogens for generated ROS. Other possible negative effects include light screening, competitive photon absorption, adsorption on the catalyst surface (thereby inhibiting its photocatalytic activity), etc. Besides, some matrix components may serve as nutrients for pathogens, thus hindering the disinfection process. Each type of water/wastewater would require a tailor-made approach and the variables that were shown to influence the processes-catalyst/oxidant concentrations, incident radiation flux, and pH-need to be adjusted in order to achieve the required degree of pollutant and pathogen removal. Overall, the solar-enhanced AOPs hold promise as an environmentally-friendly way to substitute or supplement conventional water/wastewater treatment, particularly in areas without access to centralized drinking water or sewage/wastewater treatment facilities.

Degradation of pharmaceuticals from membrane biological reactor sludge with Trametes versicolor.

PubMed

Llorens-Blanch, Guillem; Badia-Fabregat, Marina; Lucas, Daniel; Rodriguez-Mozaz, Sara; Barceló, Damià; Pennanen, Taina; Caminal, Gloria; Blánquez, Paqui

2015-02-01

Emerging contaminants are a wide group of chemical products that are found at low concentrations in the environment. These contaminants can be either natural, e.g., estrogens, or synthetics, such as pesticides and pharmaceuticals, which can enter the environment through the water and sludge from wastewater treatment plants (WWTP). The growth of Trametes versicolor on membrane biological reactor (MBR) sludge in bioslurry systems at the Erlenmeyer scale was assessed and its capacity for removing pharmaceutical and personal care products (PPCPs) was evaluated. The ability of the fungus to remove hydrochlorothiazide (HZT) from liquid media cultures was initially assessed. Consequently, different bioslurry media (complete nutrient, glucose and no-nutrient addition) and conditions (sterile and non-sterile) were tested, and the removal of spiked HZT was monitored under each condition. The highest spiked HZT removal was assessed under non-sterile conditions without nutrient addition (93.2%). Finally, the removal assessment of a broad set of pharmaceuticals was performed in non-spiked bioslurry. Under non-sterile conditions, the fungus was able to completely degrade 12 out of the 28 drugs initially detected in the MBR sludge, achieving an overall degradation of 66.9%. Subsequent microbial analysis showed that the microbial diversity increased after 15 days of treatment, but there was still some T. versicolor in the bioslurry. Results showed that T. versicolor can be used to remove PPCPs in bioslurry systems under non-sterile conditions, without extra nutrients in the media, and in matrices as complex as an MBR sludge.

Small-seeded Hakea species tolerate cotyledon loss better than large-seeded congeners

PubMed Central

El-Amhir, Sh-hoob; Lamont, Byron B.; He, Tianhua; Yan, George

2017-01-01

Six Hakea species varying greatly in seed size were selected for cotyledon damage experiments. The growth of seedlings with cotyledons partially or completely removed was monitored over 90 days. All seedlings perished by the fifth week when both cotyledons were removed irrespective of seed size. Partial removal of cotyledons caused a significant delay in the emergence of the first leaf, and reduction in root and shoot growth of the large-seeded species. The growth of seedlings of small-seeded species was less impacted by cotyledon damage. The rate of survival, root and shoot lengths and dry biomass of the seedlings were determined after 90 days. When seedlings were treated with balanced nutrient solutions following removal of the cotyledons, survival was 95–98%, but 0% when supplied with nutrient solutions lacking N or P or with water only. The addition of a balanced nutrient solution failed to restore complete growth of any species, but the rate of root elongation for the small-seeded species was maintained. Cotyledons provide nutrients to support early growth of Hakea seedlings, but other physiological roles for the cotyledons are also implicated. In conclusion, small-seeded Hakea species can tolerate cotyledons loss better than large-seeded species. PMID:28139668

Guidelines For Utilizing Rain Gardens as a Stormwater Management Tool in the Metropolitan Sewer District of Greater Cincinnati (MSD) - Steps to Getting off of the Storwater "Grid"

EPA Science Inventory

Rain gardens are designed to capture and infiltrate rainwater in the landscape. These gardens are also called "rain water gardens". Rainwater is routed to the garden and filtered naturally by the plants and soils in the garden. This filtration process removes nutrients and poll...

Silvicultural management within streamside management zones of intermittent streams: effects on decomposition, productivity, nutrient cycling, and channel vegetation

Treesearch

R. Governo; B. G. Lockaby; Robert B. Rummer; C. Colson

2004-01-01

The purpose of this watershed study on three intermittent streams was to evaluate responses of riparian processes to three streamside management zone (SMZ) treatments; no harvest, clearcut, and partial hawest (50% basal area removal). Riparian response variables measured included litter$all, leaf litter decomposition, understory vegetation, soil temperature and water...

The influence of duckweed species diversity on biomass productivity and nutrient removal efficiency in swine wastewater.

PubMed

Zhao, Zhao; Shi, Huijuan; Liu, Yang; Zhao, Hai; Su, Haifeng; Wang, Maolin; Zhao, Yun

2014-09-01

The effect of temperature, light intensity, nitrogen and phosphorus concentrations on the biomass and starch content of duckweed (Landoltia punctata OT, Lemna minor OT) in monoculture and mixture were assessed. Low light intensity promoted more starch accumulation in mixture than in monoculture. The duckweed in mixture had higher biomass and nutrient removal efficiency than those in monoculture in swine wastewater. Moreover, the ability of L. punctata C3, L. minor C2, Spirodela polyrhiza C1 and their mixtures to recovery nutrients and their biomass were analyzed. Results showed that L. minor C2 had the highest N and P content, while L. punctata C3 had the highest starch content, and the mixture of L. punctata C3 and L. minor C2 had the greatest nutrient removal rate and the highest biomass. Compared with L. punctata C3 and L. minor C2 in monoculture, their biomass in mixture increased by 17.0% and 39.8%, respectively. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of cyanobacteria: Spirulina maxima for growth, nutrient removal, and quality on waste-effluent media in batch cultures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tadros, M.G.; Phillips, J.

1992-01-01

Spirulina maxima, a semi-microscopic filamentous blue-green alga, was inoculated in synthetic and waste media of different sources. The alga was evaluated for growth yield, uptake of nutrients and chemical composition. The removal rate of N and P was rapid during the first week of growth. At the end of the second week, more than 90% of the total -P and -N was removed. The mass of alga was high. The quality of the alga obtained in different media did not show much variations, except when the medium was limited in nutrients. Results indicated that Spirulina may be integrated into themore » effluent treatment system. Recycling waste materials not only minimizes the problem of water pollution but also revitalizes the inherently rich nutrients of waste. The biomass obtained from cultivation of Spirulina in these wastewater media may be used as a pigment-protein supplement in animal feed and as raw material for certain chemicals.« less

In situ denitrification and DNRA rates in soils and underlying groundwater of an integrated constructed wetland

NASA Astrophysics Data System (ADS)

Mofizur Rahman Jahangir, Mohammad; Fenton, Owen; McAleer, Eoin; Carroll, Paul; Harrington, Rory; Johnston, Paul; Müller, Christoph; Richards, Karl

2015-04-01

Nitrogen (N) removal efficiency in constructed wetlands (CW) is low and again it does not in itself explain whether the removed N species are reactive or benign. Evaluation of environmental benefits of CW necessitates knowing N removal mechanisms and the fate of the removed N in such system. In situ denitrification and DNRA (dissimilatory nitrate reduction to ammonium) rates were measured in an earthen lined 5-cell integrated CW using 15N-enriched nitrate (NO3--N) push-pull method. Measurements were conducted in 2 groundwater depths (shallow- soils in CW bed; and deep- 4 m below CW soils) in 2 contrasting cells (high vs. low nutrient loads) of the CW. Denitrification (N¬2O-N + N2-N) and DNRA were the major NO3--N removal processes accounting together for 54-79% of the total biochemical removal of the applied NO3--N. Of which 14-17 and 40-68% were removed by denitrification and DNRA, respectively. Both the processes significantly differed with CW cells indicating that N transformations depend on the rate of nutrient loads in different cells. They were significantly higher in shallow than deep groundwater. Environmental conditions were favourable for both the processes (i.e. low dissolved oxygen and low redox potential, high dissolved organic carbon, high total carbon and high dissolved organic N) but DNRA rate was favoured over denitrification by high ambient NH4+ concentrations, reduced sulphide and low pH (5.9 - 7.0). Low pH might have limited denitrification to some extent to an incomplete state, being evident by a high N2O-N/(N2O-N+N2-N) ratio (0.35 ± 0.17, SE). Relatively higher N2O-N/(N2O-N+N2-N) ratio and higher DNRA rate over denitrification suggest that the end products of N transformations are reactive. This N2O can be consumed to N2 and/or emit to atmosphere directly and indirectly. The DNRA rate and accumulation of NH4+ indicated that CW is a net source of NH4+ in groundwater. Ammonium produced by DNRA can be fixed in soils and, when exchange sites are saturated, can flow to ground and surface waters. These results suggest that conventional input - output balance for N removal is misleading unless the removal mechanisms are fully understood and the fate of the removed N are known.

Simultaneous nutrient removal, optimised CO2 mitigation and biofuel feedstock production by Chlorogonium sp. grown in secondary treated non-sterile saline sewage effluent.

PubMed

Lee, Kwan Yin; Ng, Tsz Wai; Li, Guiying; An, Taicheng; Kwan, Ka Ki; Chan, King Ming; Huang, Guocheng; Yip, Ho Yin; Wong, Po Keung

2015-10-30

The phycoremediation process has great potential for effectively addressing environmental pollution. To explore the capabilities of simultaneous algal nutrient removal, CO2 mitigation and biofuel feedstock production from spent water resources, a Chlorogonium sp. isolated from a tilapia pond in Hong Kong was grown in non-sterile saline sewage effluent for a bioremediation study. With high removal efficiencies of NH3-N (88.35±14.39%), NO3(-)-N (85.39±14.96%), TN (93.34±6.47%) and PO4(3-)-P (91.80±17.44%), Chlorogonium sp. achieved a CO2 consumption rate of 58.96 mg L(-1) d(-1), which was optimised by the response surface methodology. Under optimised conditions, the lipid content of the algal biomass reached 24.26±2.67%. Overall, the isolated Chlorogonium sp. showed promising potential in the simultaneous purification of saline sewage effluent in terms of tertiary treatment and CO2 sequestration while delivering feedstock for potential biofuel production in a waste-recycling manner. Copyright © 2015 Elsevier B.V. All rights reserved.

Vertical flow constructed wetlands: kinetics of nutrient and organic matter removal.

PubMed

Pérez, M M; Hernández, J M; Bossens, J; Jiménez, T; Rosa, E; Tack, F

2014-01-01

The kinetics of organic matter and nutrient removal in a pilot vertical subsurface wetland with red ferralitic soil as substrate were evaluated. The wetland (20 m(2)) was planted with Cyperus alternifolius. The domestic wastewater that was treated in the wetland had undergone a primary treatment consisting of a septic moat and a buffer tank. From the sixth week of operation, the performance of the wetland stabilized, and a significant reduction in pollutant concentration of the effluent wastewater was obtained. Also a significant increase of dissolved oxygen (5 mg/l) was obtained. The organic matter removal efficiency was greater than 85% and the nutrient removal efficiency was greater than 75% in the vertical subsurface wetland. Nitrogen and biochemical oxygen demand (BOD) removal could be described by a first-order model. The kinetic constants were 3.64 and 3.27 d(-1) for BOD and for total nitrogen, respectively. Data on the removal of phosphorus were adapted to a second-order model. The kinetic constant was 0.96 (mg/l)(-1) d(-1). The results demonstrated the potential of vertical flow constructed wetlands to clean treated domestic wastewater before discharge into the environment.

How the novel integration of electrolysis in tidal flow constructed wetlands intensifies nutrient removal and odor control.

PubMed

Ju, Xinxin; Wu, Shubiao; Huang, Xu; Zhang, Yansheng; Dong, Renjie

2014-10-01

Intensified nutrient removal and odor control in a novel electrolysis-integrated tidal flow constructed wetland were evaluated. The average removal efficiencies of COD and NH4(+)-N were above 85% and 80% in the two experimental wetlands at influent COD concentration of 300 mg/L and ammonium nitrogen concentration of 60 mg/L regardless of electrolysis integration. Effluent nitrate concentration decreased from 2.5mg/L to 0.5mg/L with the reduction in current intensity from 1.5 mA/cm(2) to 0.57 mA/cm(2). This result reveals the important role of current intensity in nitrogen transformation. Owing to the ferrous and ferric iron coagulant formed through the electro-dissolution of the iron anode, electrolysis integration not only exerted a positive effect on phosphorus removal but also effectively inhibited sulfide accumulation for odor control. Although electrolysis operation enhanced nutrient removal and promoted the emission of CH4, no significant difference was observed in the microbial communities and abundance of the two experimental wetlands. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cultivation of Chlorella vulgaris JSC-6 with swine wastewater for simultaneous nutrient/COD removal and carbohydrate production.

PubMed

Wang, Yue; Guo, Wanqian; Yen, Hong-Wei; Ho, Shih-Hsin; Lo, Yung-Chung; Cheng, Chieh-Lun; Ren, Nanqi; Chang, Jo-Shu

2015-12-01

Swine wastewater, containing a high concentration of COD and ammonia nitrogen, is suitable for the growth of microalgae, leading to simultaneous COD/nutrients removal from the wastewater. In this study, an isolated carbohydrate-rich microalga Chlorella vulgaris JSC-6 was adopted to perform swine wastewater treatment. Nearly 60-70% COD removal and 40-90% NH3-N removal was achieved in the mixotrophic and heterotrophic culture, depending on the dilution ratio of the wastewater, while the highest removal percentage was obtained with 20-fold diluted wastewater. Mixotrophic cultivation by using fivefold diluted wastewater resulted in the highest biomass concentration of 3.96 g/L. The carbohydrate content of the microalga grown on the wastewater can reach up to 58% (per dry weight). The results indicated that the microalgae-based wastewater treatment can efficiently reduce the nutrients and COD level, and the resulting microalgal biomass had high carbohydrate content, thereby having potential applications for the fermentative production of biofuels or chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of increased biomass removal on the biogeochemistry of two Norwegian forest ecosystems

NASA Astrophysics Data System (ADS)

Lange, H.; Clarke, N.; Kjønaas, O. J.; Aas, W.; Andreassen, K.; Børja, I.; Bratli, H.; Eich-Greatorex, S.; Eldhuset, T.; Holt-Hanssen, K.

2009-04-01

Increased removal of biomass from forested ecosystems for use as an alternative source of energy is an option in several countries. E.g., it is planned to double the use of bioenergy from all sources until 2020 in Norway. A large fraction of this increase is coming from forest resources, e.g. by removing harvest residues like branches and tops. This removal will reduce the supply of nutrients and organic matter to the forest soil, and may in the longer term increase the risk for future nutrient imbalance, soil erosion on steep slopes, reduced forest production, and changes in biodiversity and ground vegetation species composition. However, field experiments so far have found contrasting results in this respect. Soil effects of increased biomass removal will be closely related to soil organic matter (SOM) dynamics, litter quality, and turnover rates. Harvest intensity may affect the decomposition of existing SOM as well as the build-up of new SOM from litter and forest residues, by changing factors like soil temperature and moisture as well as amount and type of litter input. Changes in input of litter with different nutrient concentrations and decomposition patterns along with changes in SOM decomposition will affect the total storage of carbon, nitrogen and other vital nutrients in the soil. In the context of a Norwegian research project started in 2009, we will quantify how different harvesting regimes lead to different C addition to soil, and determine which factors have the greatest effect on decomposition of SOM under different environmental conditions. Two Norway spruce forest ecosystems will be investigated, one in eastern and one in western Norway, representing different climatic conditions and landscape types. At each location, two treatment regimes will be tested: (1) conventional harvesting (CH), with residues left on-site, and (2) aboveground whole-tree harvest (WTH), with branches, needles, and tops removed. Input of different forest residues will be quantified post harvest. Soil water at 30 cm soil depth will be analysed for nutrients, and element fluxes will be estimated to provide information about nutrient leaching. Soil respiration will be measured, along with lab decomposition studies under different temperature and moisture regimes. Long term in situ decomposition studies will be carried out in the WTH plots using three different tree compartments (needles, coarse twigs, fine roots) decomposing in litter bags, in order to determine their limit value. The structure of the fungal community will be determined by soil core sampling and molecular techniques. Understory vegetation will be sampled to determine its biomass, and the frequency of all vascular plants, bryophytes and lichens will be estimated. After harvesting, replanting will be carried out. Seedling survival, causes of mortality and potential damage, growth, and needle nutrients will be monitored. Results from these studies will be used to identify key processes explaining trends observed in two series of ongoing long-term whole-tree thinning trials. We shall combine knowledge obtained using field experiments with results of modelling and data from the Norwegian Monitoring Programme for Forest Damage and the National Forest Inventory. The overall project aim is to predict and map the ecologically most suitable areas for increased harvesting of branches and tops on a regional scale, and to identify uncertainties and additional knowledge needed to improve current predictions.

Nutrient concentrations in coarse and fine woody debris of Populus tremuloides Michx.-dominated forests, northern Minnesota, USA

USGS Publications Warehouse

Klockow, Paul A.; D'Amato, Anthony W.; Bradford, John B.; Fraver, Shawn

2014-01-01

Contemporary forest harvesting practices, specifically harvesting woody biomass as a source of bioenergy feedstock, may remove more woody debris from a site than conventional harvesting. Woody debris, particularly smaller diameter woody debris, plays a key role in maintaining ecosystem nutrient stores following disturbance. Understanding nutrient concentrations within woody debris is necessary for assessing the long-term nutrient balance consequences of altered woody debris retention, particularly in forests slated for use as bioenergy feedstocks. Nutrient concentrations in downed woody debris of various sizes, decay classes, and species were characterized within one such forest type, Populus tremuloides Michx.-dominated forests of northern Minnesota, USA. Nutrient concentrations differed significantly between size and decay classes and generally increased as decay progressed. Fine woody debris (≤ 7.5 cm diameter) had higher nutrient concentrations than coarse woody debris (> 7.5 cm diameter) for all nutrients examined except Na and Mn, and nutrient concentrations varied among species. Concentrations of N, Mn, Al, Fe, and Zn in coarse woody debris increased between one and three orders of magnitude, while K decreased by an order of magnitude with progressing decay. The variations in nutrient concentrations observed here underscore the complexity of woody debris nutrient stores in forested ecosystems and suggest that retaining fine woody debris at harvest may provide a potentially important source of nutrients following intensive removals of bioenergy feedstocks.

Effects of adding bulking agent, inorganic nutrient and microbial inocula on biopile treatment for oil-field drilling waste.

PubMed

Ma, Jie; Yang, Yongqi; Dai, Xiaoli; Chen, Yetong; Deng, Hanmei; Zhou, Huijun; Guo, Shaohui; Yan, Guangxu

2016-05-01

Contamination from oil-field drilling waste is a worldwide environmental problem. This study investigated the performance of four bench-scale biopiles in treating drilling waste: 1) direct biopile (DW), 2) biopile plus oil-degrading microbial consortium (DW + M), 3) biopile plus microbial consortium and bulking agents (saw dust) (DW + M + BA), 4) biopile plus microbial consortium, bulking agents, and inorganic nutrients (Urea and K2HPO4) (DW + M + BA + N). Ninety days of biopiling removed 41.0%, 44.0%, 55.7% and 87.4% of total petroleum hydrocarbon (TPH) in the pile "DW", "DW + M", "DW + M + BA", and "DW + M + BA + N" respectively. Addition of inorganic nutrient and bulking agents resulted in a 56.9% and 26.6% increase in TPH removal efficiency respectively. In contrast, inoculation of hydrocarbon-degrading microorganisms only slightly enhanced the contaminant removal (increased 7.3%). The biopile with stronger contaminant removal also had higher pile temperature and lower pile pH (e.g., in "DW + M + BA + N"). GC-MS analysis shows that biopiling significantly reduced the total number of detected contaminants and changed the chemical composition. Overall, this study shows that biopiling is an effective remediation technology for drilling waste. Adding inorganic nutrients and bulking agents can significantly improve biopile performance while addition of microbial inocula had minimal positive impacts on contaminant removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of alkylphenols and polybromodiphenylethers by a biofiltration treatment plant during dry and wet-weather periods.

PubMed

Gilbert, S; Gasperi, J; Rocher, V; Lorgeoux, C; Chebbo, G

2012-01-01

This paper investigates the occurrence of alkylphenols (APs) and polybromodiphenylethers (PBDEs) in raw wastewater during dry and wet-weather periods, and their removal by physico-chemical lamellar settling and biofiltration techniques. Due to in-sewer deposit erosion and, to a lesser extent, to external inputs, raw effluents exhibit from 1.5 to 5 times higher AP and PBDE concentrations during wet periods compared with dry ones. The lamellar settler obtains high removal of APs and PBDEs under both dry and wet-weather flows (>53% for Σ(6)AP and >89% for Σ(4)PBDE), confirming the insensitivity of this technique to varying influent conditions. Indeed, despite the higher pollutant concentrations observed in raw effluents under wet-weather flows, adjusting the addition of coagulant-flocculent allows for efficient removal. By combining physical and biological processes, the biofiltration unit treats nutrient pollution, as well as Σ(6)AP and Σ(4)PBDE contamination (58 ± 5% and 75 ± 6% respectively). Although the operating conditions of the biofiltration unit are modified during wet periods, the performance in nutrient pollution, APs and light PBDE congeners remains high. Nevertheless, lower efficiency has been noted in nitrogen pollution, i.e. no denitrification occurs, and BDE-209 (not removed during wet-weather periods). In conclusion, this study demonstrates that the combination of both techniques treats AP and PBDE pollution efficiently during dry periods, but that they are also suitable for stormwater treatment.

Constructed wetlands may lower inorganic nutrient inputs but enhance DOC loadings into a drinking water reservoir in North Wales.

PubMed

Scholz, C; Jones, T G; West, M; Ehbair, A M S; Dunn, C; Freeman, C

2016-09-01

The objective of this study was to monitor a newly constructed wetland (CW) in north Wales, UK, to assess whether it contributes to an improvement in water quality (nutrient removal) of a nearby drinking water reservoir. Inflow and outflow of the Free Water Surface (FWS) CW were monitored on a weekly basis and over a period of 6 months. Physicochemical parameters including pH, conductivity and dissolved oxygen (DO) were measured, as well as nutrients and dissolved organic and inorganic carbon (DOC, DIC) concentration. The CW was seen to contribute to water quality improvement; results show that nutrient removal took place within weeks after construction. It was found that 72 % of initial nitrate (N03 (-)), 53 % of initial phosphate (PO4 (3-)) and 35 % of initial biological oxygen demand (BOD) were removed, calculated as a total over the whole sampling period. From our study, it can be concluded that while inorganic nutrients do decline in CWs, the DOC outputs increases. This may suggest that CWs represent a source for DOC. To assess the carbon in- and output a C budget was calculated.

Geomorphic stream restoration as an approach for reducing nutrients in degraded urban watersheds

EPA Science Inventory

Elevated nitrate levels in streams and groundwater pose human and ecological threats. Stream restoration may improve the nutrient removal capacity of streams, yet few studies have investigated the effectiveness of restoration as a nutrient BMP despite significant national effort...

Logging residue removal after thinning in boreal forests: long-term impact on the nutrient status of Norway spruce and Scots pine needles.

PubMed

Luiro, Jukka; Kukkola, Mikko; Saarsalmi, Anna; Tamminen, Pekka; Helmisaari, Heljä-Sisko

2010-01-01

The aim of this study was to compare how conventional stem harvesting (CH) and whole-tree harvesting (WTH) in the first, and in some cases also in the second, thinning affect the needle nutrient status of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) stands in Finland. A series of 12 long-term field experiments was studied. The experiments were established during 1978-86. The effects of logging residue removal after thinnings on the needle nutrient concentrations were generally minor and without any overall trends, but there were differences between experiments. Trees tend to maintain their current needle nutrient concentrations at the same level by re-utilizing the nutrients stored in the older tissues and by changing C allocation in the whole tree. Thus, needle analysis should be combined with stem growth data in order to achieve a more comprehensive understanding of the effects of WTH on the nutrient status of trees.

Calibration and simulation of two large wastewater treatment plants operated for nutrient removal.

PubMed

Ferrer, J; Morenilla, J J; Bouzas, A; García-Usach, F

2004-01-01

Control and optimisation of plant processes has become a priority for WWTP managers. The calibration and verification of a mathematical model provides an important tool for the investigation of advanced control strategies that may assist in the design or optimization of WWTPs. This paper describes the calibration of the ASM2d model for two full scale biological nitrogen and phosphorus removal plants in order to characterize the biological process and to upgrade the plants' performance. Results from simulation showed a good correspondence with experimental data demonstrating that the model and the calibrated parameters were able to predict the behaviour of both WWTPs. Once the calibration and simulation process was finished, a study for each WWTP was done with the aim of improving its performance. Modifications focused on reactor configuration and operation strategies were proposed.

Mixed Wastewater Coupled with CO2 for Microalgae Culturing and Nutrient Removal

PubMed Central

Yao, Lili; Shi, Jianye; Miao, Xiaoling

2015-01-01

Biomass, nutrient removal capacity, lipid productivity and morphological changes of Chlorella sorokiniana and Desmodesmus communis were investigated in mixed wastewaters with different CO2 concentrations. Under optimal condition, which was 1:3 ratio of swine wastewater to second treated municipal wastewater with 5% CO2, the maximum biomass concentrations were 1.22 g L-1 and 0.84 g L-1 for C. sorokiniana and D. communis, respectively. Almost all of the ammonia and phosphorus were removed, the removal rates of total nitrogen were 88.05% for C. sorokiniana and 83.18% for D. communis. Lipid content reached 17.04% for C. sorokiniana and 20.37% for D. communis after 10 days culture. CO2 aeration increased intracellular particle numbers of both microalgae and made D. communis tend to be solitary. The research suggested the aeration of CO2 improve the tolerance of microalgae to high concentration of NH4-N, and nutrient excess stress could induce lipid accumulation of microalgae. PMID:26418261

Simultaneous treatment of food-waste recycling wastewater and cultivation of Tetraselmis suecica for biodiesel production.

PubMed

Heo, Sung-Woon; Ryu, Byung-Gon; Nam, Kibok; Kim, Woong; Yang, Ji-Won

2015-07-01

There is an increasing interest in the use of cultivated microalgae to simultaneously produce biodiesel and remove nutrients from various wastewaters. For this purpose, Tetraselmis suecica was cultivated in flasks and fermenters using diluted food-waste recycling wastewater (FRW). The effect of FRW dilution on T. suecica growth and nutrient removal was initially tested in flasks. The maximal microalgal concentration after 14 days was in medium with a twofold dilution (28.3 × 10(6) cells/mL) and a fivefold dilution (25.5 × 10(6) cells/mL). When fivefold diluted medium was used in fermenters, the final dry cell weight of T. suecica was 2.0 g/L. The removal efficiencies of ammonium and phosphate in the fermenters were 99.0 and 52.3%, respectively. In comparison with the results of previous studies, the growth data of T. suecica in the FRW medium indicate that microalgal cultivation system incorporating removal of nutrients in FRW is feasible at the field level.

Solids and nutrient removal from flushed swine manure using polyacrylamides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanotti, M.B.; Hunt, P.G.

1999-12-01

Most of the organic nutrients and reduced carbon (C) materials in liquid swine manure are contained in fine suspended particles that are not separated by available mechanical separators. Treatment with polyacrylamide (PAM) polymers prior to mechanical removal or gravity settling has the potential for enhancing solids-liquid separation, thus concentrating nitrogen (N), phosphorus (P), and organic C. In this work, the authors determined PAM charge and density characteristics most desirable for swine wastewater applications and established the optimum chemical requirement. Treatments were applied to flushed manure from two swine operations in North Carolina. Cationic PAMs significantly increased solids separation while performancemore » of neutral and anionic types was not different from a control. Cationic PAMs with moderate-charge density (20%) were more effective than polymers with higher charge density. Flocs were large and effectively retained with a 1-mm screen. Optimum PAM rate varied with the amount of total suspended solids (TSS) in the liquid manure; 26 and 79 mg PAM/L for samples containing 1.5 and 4.1 g TSS/L, respectively. Corresponding TSS removal efficiencies were 90 to 94%. In contrast, screening without PAM treatment captured only 5 to 14% of the suspended solids. Polymer usage rate was consistent and averaged 2.0{degree} based on weight of dry solids produced. Volatile suspended solids (VSS) were highly correlated with TSS and comprised 79.5% of TSS. Chemical oxygen demand (COD) and organic nutrient concentrations in the effluent were also significantly decreased by PAM treatment. The decrease of COD concentration, an important consideration for odor control, was linearly related with removal of suspended solids, at a rate of 2.0 g COD/g TSS and 2.6 g COD/g VSS. Removal efficiency of organic N and P followed approximately a 1:1 relationship with removal efficiency of TSS. Chemical cost to capture 90% of the suspended solids was estimated to be $0.026 per hog per day ($2.79 per finished hog). Results obtained indicate that PAM treatment is very effective for removal of manure solids, COD, and organic nutrients from flushed swine effluents. The technology provides an attractive alternative to existing liquid manure handling methods for conserving nutrients and avoiding excessive nutrient application in areas where swine production is concentrated.« less

Anaerobic digestion of wastewater from the fruit juice industry: experiments and modeling.

PubMed

Zerrouki, Souhaib; Rihani, Rachida; Bentahar, Fatiha; Belkacemi, Khaled

2015-01-01

Anaerobic digestion of wastewater from the fruit juice industry was carried out in a batch digester. To study the effect of the pH values as well as the nutrient medium on the fermentation process, different parameters were monitored under mesophilic temperature, such as cumulative biogas volume, chemical oxygen demand (COD), total sugar, and biomass growth. It was found that for all cases, the COD concentration decreased with time. The lowest value reached was obtained when the nutrient medium was added; it was about 110 g/L after 480 h. In such cases, the COD removal reached about 80%; the highest cumulative biogas volume of about 5,515.8 NmL was reached after 480 h testing; and the lowest value reached was about 2,862.3 NmL in the case of peach-substrate containing sodium sulfite. The addition of nutrient medium improved the cumulative biogas production as well as the COD abatement. Measurement of the biogas composition highlighted three gaseous components, namely, methane (56.52%), carbon dioxide (20.14%), and hydrogen sulfide (23.34%). The modified Gompertz equation and the first-order kinetic model were used to describe the cumulative biogas production and the organic matter removal, respectively. A good agreement was found between simulated and experimental data.

Degradation of typical N-nitrosodimethylamine (NDMA) precursors and its formation potential in anoxic-aerobic (AO) activated sludge system.

PubMed

Wang, Lin; Li, Yongmei; He, Guodong

2014-01-01

N-nitrosodimethylamine (NDMA) is an emerging disinfection byproduct. Removal of its potential precursors is considered as an effective method to control NDMA. In this study, four typical NDMA precursors (dimethylamine (DMA), trimethylamine (TMA), dimethylformamide (DMFA) and dimethylaminobenzene (DMAB)) were selected, and their removal capacities by activated sludge were investigated. Batch experiments indicated that removal of NDMA precursors was better under aerobic condition than anoxic condition; and their specific degradation rates follow the order of DMA > TMA > DMFA > DMAB. In anoxic-aerobic (AO) activated sludge system, the optimal hydraulic retention time and sludge retention time were 10 h and 20 d, respectively, for the removal of both NDMA precursors (four selected NDMA precursors and NDMA formation potential (NDMA FP)) and nutrients. Our results also suggested that there was a positive correlation between NDMA FP and dissolved organic nitrogen (DON) in wastewater. The removal efficiency of NDMA FP was in the range of 46.8-72.5% in the four surveyed wastewater treatment plants except the one which adopted chemically enhanced primary process. The results revealed that the AO system had the advantage of removing NDMA FP. Our results are helpful for the knowledge of the removals of NDMA precursors during activated sludge treatment processes.

Pearl aquaculture-profitable environmental remediation?

PubMed

Gifford, S; Dunstan, R H; O'Connor, W; Roberts, T; Toia, R

2004-02-05

Bivalve molluscs are filter feeders, with pearl oysters able to filter water at rates up to 25 lh(-1)g(-1) of dry wt. tissue. Since this process leads to rapid bioaccumulation of recalcitrant pollutants such as heavy metals, organochlorine pesticides and hydrocarbons from impacted sites, it has prompted the widespread use of molluscs as biomonitors to quantify levels of marine pollution. This paper proposes pearl oyster deployment as a novel bioremediation technology for impacted sites to remove toxic contaminants, reduce nutrient loads and lower concentrations of microbial pathogens. Estimates extrapolated from the literature suggest that a modest pearl oyster farm of 100 t oyster material per year could remove 300 kg heavy metals plus 24 kg of organic contaminants via deposition into the tissue and shell. Furthermore, it was estimated that up to 19 kg of nitrogen may be removed from the coastal ecosystem per tonne of pearl oyster harvested. Pearl oysters are also likely to filter substantial amounts of sewage associated microbial pathogens from the water column. Method of cultivation and site selection are the key to minimising negative environmental impacts of bivalve cultivation. Deployment of oysters at sites with high nutrient and contaminant loadings would be advantageous, as these compounds would be removed from the ecosystem whilst generating a value-added product. Future potential may exist for harvesting bio-concentrated elements for commercial production.

Bacterial community dynamics in surface flow constructed wetlands for the treatment of swine waste.

PubMed

Ibekwe, A M; Ma, J; Murinda, Shelton; Reddy, G B

2016-02-15

Constructed wetlands are generally used for the removal of waste from contaminated water. In the swine production system, wastes are traditionally flushed into an anaerobic lagoon which is then sprayed on agricultural fields. However, continuous spraying of lagoon wastewater on fields can lead to high N and P accumulations in soil or lead to runoff which may contaminate surface or ground water with pathogens and nutrients. In this study, continuous marsh constructed wetland was used for the removal of contaminants from swine waste. Using pyrosequencing, we assessed bacterial composition within the wetland using principal coordinate analysis (PCoA) which showed that bacterial composition from manure influent and lagoon water were significantly different (P=0.001) from the storage pond to the final effluent. Canonical correspondence analysis (CCA) showed that different bacterial populations were significantly impacted by ammonium--NH4 (P=0.035), phosphate--PO4(3-) (P=0.010), chemical oxygen demand--COD (P=0.0165), total solids--TS (P=0.030), and dissolved solids--DS (P=0.030) removal, with 54% of the removal rate explained by NH4+PO4(3-) according to a partial CCA. Our results showed that different bacterial groups were responsible for the composition of different wetland nutrients and decomposition process. This may be the major reason why most wetlands are very efficient in waste decomposition. Published by Elsevier B.V.

Domestic wastewater treatment with purple phototrophic bacteria using a novel continuous photo anaerobic membrane bioreactor.

PubMed

Hülsen, Tim; Barry, Edward M; Lu, Yang; Puyol, Daniel; Keller, Jürg; Batstone, Damien J

2016-09-01

A key future challenge of domestic wastewater treatment is nutrient recovery while still achieving acceptable discharge limits. Nutrient partitioning using purple phototrophic bacteria (PPB) has the potential to biologically concentrate nutrients through growth. This study evaluates the use of PPB in a continuous photo-anaerobic membrane bioreactor (PAnMBR) for simultaneous organics and nutrient removal from domestic wastewater. This process could continuously treat domestic wastewater to discharge limits (<50 mgCOD L(-1), 5 mgN L(-1), 1.0 mgP L(-1)). Approximately 6.4 ± 1.3 gNH4-N and 1.1 ± 0.2 gPO4-P for every 100 gSCOD were removed at a hydraulic retention time of 8-24 h and volumetric loading rates of 0.8-2.5 COD kg m(3) d(-1). Thus, a minimum of 200 mg L(-1) of ethanol (to provide soluble COD) was required to achieve these discharge limits. Microbial community through sequencing indicated dominance of >60% of PPB, though the PPB community was highly variable. The outcomes from the current work demonstrate the potential of PPB for continuous domestic (and possibly industrial) wastewater treatment and nutrient recovery. Technical challenges include the in situ COD supply in a continuous reactor system, as well as efficient light delivery. Addition of external (agricultural or fossil) derived organics is not financially nor environmentally justified, and carbon needs to be sourced internally from the biomass itself to enable this technology. Reduced energy consumption for lighting is technically feasible, and needs to be addressed as a key objective in scaleup. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal.

PubMed

Bu, Fan; Hu, Xiang; Xie, Li; Zhou, Qi

2015-04-01

The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic-anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-β-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating organisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fermentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49-5.99 g N/(kg MLVSS⋅h) (MLVSS is mixed liquor volatile suspended solids) and 6.63-6.81 g N/(kg MLVSS⋅h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes.

Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal*

PubMed Central

Bu, Fan; Hu, Xiang; Xie, Li; Zhou, Qi

2015-01-01

The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal (BNR) from municipal wastewater in anaerobic-anoxic-aerobic sequencing batch reactors (SBRs). Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound (sodium acetate) served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-β-hydroxyalkanoates (PHAs), and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating organisms (PAOs) and denitrifying phosphorus accumulating organisms (DPAOs) demonstrated that the proportion of DPAOs to PAOs reached 62.6% (Day 86) and 61.8% (Day 65) when using cassava stillage and its anaerobic fermentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates (NURs) of the cassava by-products were in the range of 5.49–5.99 g N/(kg MLVSS∙h) (MLVSS is mixed liquor volatile suspended solids) and 6.63–6.81 g N/(kg MLVSS∙h), respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes. PMID:25845364

ENERGY AND NUTRIENT EXTRACTION FROM ONSITE WASTEWATER - PHASE I

EPA Science Inventory

Onsite wastewater systems are a significant source of nutrient loading to the environment and there is a demand for technologies that remove nutrients at the source. Most desired are passive, low-...

Measuring nutrient flux in Pacific Coast salt marshes using fluctuating water-level chambers

EPA Science Inventory

Nutrient removal from the water column is an important ecosystem function that contributes to the production of clean water, a final valued ecosystem service of wetlands. However, little data is currently available for nutrient exchange in Pacific Northwest tidal ecosystems. We h...

Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants

PubMed Central

Tsydenova, Oyuna; Batoev, Valeriy; Batoeva, Agniya

2015-01-01

The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fenton. Complex water matrices with high loads of pathogens and chemical pollutants negatively affect the efficiency of disinfection and pollutant removal. This is due to competition between chemical substances and pathogens for generated ROS. Other possible negative effects include light screening, competitive photon absorption, adsorption on the catalyst surface (thereby inhibiting its photocatalytic activity), etc. Besides, some matrix components may serve as nutrients for pathogens, thus hindering the disinfection process. Each type of water/wastewater would require a tailor-made approach and the variables that were shown to influence the processes—catalyst/oxidant concentrations, incident radiation flux, and pH—need to be adjusted in order to achieve the required degree of pollutant and pathogen removal. Overall, the solar-enhanced AOPs hold promise as an environmentally-friendly way to substitute or supplement conventional water/wastewater treatment, particularly in areas without access to centralized drinking water or sewage/wastewater treatment facilities. PMID:26287222

Nutrient balancing for phytoremediation enhancement of urea manufacturing raw wastewater.

PubMed

Yavari, Sara; Malakahmad, Amirhossein; Sapari, Nasiman B; Yavari, Saba; Khan, Eakalak

2017-11-01

Application of urea manufacturing wastewater to teak (Tectona grandis) trees, a fast growing tropical timber plants, is an environmentally-friendly and cost-effective alternative for treatment of nitrogen-rich wastewater. However, the plant growth is strongly limited by lack of phosphorus (P) and potassium (K) elements when the plants are irrigated with wastewater containing high concentration of nitrogen (N). A greenhouse experiment was conducted to optimize the efficiency of teak-based remediation systems in terms of nutrient balance. Twelve test solutions consisted of 4 levels of P (95, 190, 570, 1140 mgL -1 ) and 3 levels of K (95, 190, 570 mgL -1 ) with a constant level of N (190 mgL -1 ) were applied to teak seedlings every four days during the study period. Evapotranspiration rate, nutrient removal percentage, leaf surface area, dry weight and nutrient contents of experimental plants were determined and compared with those grown in control solution containing only N (N:P:K = 1:0:0). Teak seedlings grown in units with 1:0.5:1 N:P:K ratio were highly effective at nutrient removal upto 47%, 48% and 49% for N, P and K, respectively. Removal efficiency of teak plants grown in other experimental units decreased with increasing P and K concentrations in test solutions. The lowest nutrient removal and plant growth were recorded in units with 1:6:0.5 N:P:K ratio which received the highest ratio of P to K. The findings indicated that teak seedlings functioned effectively as phytoremediation plants for N-rich wastewater treatment when they were being supplied with proper concentrations of P and K. Copyright © 2017. Published by Elsevier Ltd.

On-site nutrient recovery and removal from source-separated urine by phosphorus precipitation and short-cut nitrification-denitrification.

PubMed

Yao, Song; Chen, Liping; Guan, Detian; Zhang, Zhongguo; Tian, Xiujun; Wang, Aimin; Wang, Guotian; Yao, Qian; Peng, Dangcong; Li, Jiuyi

2017-05-01

Source separation and treatment of human urine have been recognized as a resource-efficient alternative to conventional urban drainage, not only reducing nutrient loads on municipal wastewater treatment plants, but recovering valuable resources from waste streams. In this work, on-site phosphorus (P) recovery from real urine was carried out by using the brine from a reverse osmosis process as the flush water for urine-diverting toilets and a P precipitant, while nitrogen (N) was removed via short-cut nitrification-denitrification (SCND) in a membrane bioreactor (MBR). More than 90% of P was recovered by mixing the urine with reverse osmosis brine (1:1, v/v) under the condition of pH > 9.0. The recovered precipitates contained 10-15% of P and can potentially be reused for phosphate fertilizer production. Stable SCND was achieved in a MBR, and 45% of N was removed with the organic compounds in urine as the electron donor for denitrification. Methanol addition significantly elevated denitrification, which in turn replenished the alkalinity required for nitrification. More than 99% of P, 90% of organics and 90% of N were removed in the combined precipitation and MBR process. Nitrosomonas was observed to be the predominant ammonium-oxidizing bacteria, while nitrite-oxidizing bacteria (NOB) were absent in the microbial communities as revealed by fluorescence in situ hybridization and pyrosequencing technique. High concentrations of free ammonia and nitrite acids, as well as low dissolved oxygen, are the prevailing factors to inhibit the growth of NOB, which allows for stable operation of SCND in the MBR. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soil amendment using poplar woodchips to enhance the treatment of wastewater-originated nutrients.

PubMed

Meffe, Raffaella; de Miguel, Ángel; Martínez Hernández, Virtudes; Lillo, Javier; de Bustamante, Irene

2016-09-15

Vegetation filters, a nature based wastewater regeneration technology, have been reported as a feasible solution for small municipalities and scattered populations with limited access to sewage networks. However even when such a treatment is properly planned, the leaching of contaminants through the unsaturated zone may occur. The amendment of soil with a readily-labile source of carbon is supposed to ameliorate the removal of contaminants by stimulating microbial activity and enhancing sorption processes. In this study, lab-scale leaching column experiments were carried out to explore if the addition of woodchips to the soil could be a feasible strategy to be integrated in a vegetation filter. Two different types of arrangement of soil and woodchips layers were tested. The soil was collected from an operating vegetation filter treating wastewater of an office building characterised by a high nutrient load. Daily pulse of synthetic wastewater were applied into the columns and effluent samples were collected and analyzed for major ions, total nitrogen (NT), total phosphorous (PT) and chemical oxygen demand (COD). By the end of the experiment, NT, NO3-N and PT soil contents were also measured. Results indicate that amendments with woodchips enhance the elimination of wastewater-originated contaminants. NT removal in the columns with woodchips reaches a value of 99.4%. The main processes responsible for this elimination are NH4-N sorption and nitrification/denitrification. This latter fostered by the reduced redox conditions due to the enhanced microbial activity. High removal of PT (99%) is achieved independently of the woodchips presence due to retention and/or precipitation phenomena. The COD removal efficiency is not affected by the presence of the woodchips. The leaching of organic carbon occurs only during the experimental start-up period. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enhanced reduction of excess sludge and nutrient removal in a pilot-scale A2O-MBR-TAD system.

PubMed

Ventura, J S; Seo, S; Chung, I; Yeom, I; Kim, H; Oh, Y; Jahng, D

2011-01-01

In this study, a pilot scale anaerobic-anoxic-oxic (A2O) process with submerged membrane (MBR) in the oxic tank was coupled with thermophilic aerobic digestion (TAD) reactor and was operated for longer than 600 days to treat real domestic wastewater. Regardless of the varying conditions of the system, the A2O-MBR-TAD process removed MLSS, TCOD, BOD, TN, TP, and E. coli about 99%, 96%, 96%, 70%, 83%, and 99%, respectively. The additional TP removal of the system was due to the precipitating agent directly added in the oxic reactor, without which TP removal was about 56%. In the TAD reactor, receiving MLSS from the oxic tank (MBR), about 25% of TSS and VSS were solubilized during 2 days of retention. The effluent of the TAD reactor was recycled into the anoxic tank of A2O-MBR to provide organic carbon for denitrification and cryptic growth. By controlling the flowrate of wasting stream from the MBR, sludge production decreased to almost zero. From these results, it was concluded that the A2O-MBR-TAD process could be a reliable option for excellent effluent quality and near zero-sludge production.

Simultaneous removal of aniline, nitrogen and phosphorus in aniline-containing wastewater treatment by using sequencing batch reactor.

PubMed

Jiang, Yu; Wang, Hongyu; Shang, Yu; Yang, Kai

2016-05-01

The high removal efficiencies of traditional biological aniline-degrading systems always lead to accumulation of ammonium. In this study, simultaneous removal of aniline, nitrogen and phosphorus in a single sequencing batch reactor was achieved by using anaerobic/aerobic/anoxic (A/O/A) operational process. The removal efficiencies of COD, NH4(+)-N, TN, TP were over 95.80%, 83.03%, 87.13%, 90.95%, respectively in most cases with 250mgL(-1) of initial aniline at 6h cycle when DO was 5.5±0.5mgL(-1). Aniline was able to be completely degraded when initial concentrations were less than 750mgL(-1). When DO increased, the removal rate of NH4(+)-N and TP slightly increased along with the moderate decrease of removal efficiencies of TN. The variation of HRT had obvious influence on removal performance of pollutants. The system showed high removal efficiencies of aniline, COD and nutrients during the variation of operating conditions, which might contribute to disposal of aniline-rich industrial wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Balancing macronutrient stoichiometry to alleviate eutrophication.

PubMed

Stutter, M I; Graeber, D; Evans, C D; Wade, A J; Withers, P J A

2018-09-01

Reactive nitrogen (N) and phosphorus (P) inputs to surface waters modify aquatic environments, affect public health and recreation. Source controls dominate eutrophication management, whilst biological regulation of nutrients is largely neglected, although aquatic microbial organisms have huge potential to process nutrients. The stoichiometric ratio of organic carbon (OC) to N to P atoms should modulate heterotrophic pathways of aquatic nutrient processing, as high OC availability favours aquatic microbial processing. Heterotrophic microbial processing removes N by denitrification and captures N and P as organically-complexed, less eutrophying forms. With a global data synthesis, we show that the atomic ratios of bioavailable dissolved OC to either N or P in rivers with urban and agricultural land use are often distant from a "microbial optimum". This OC-deficiency relative to high availabilities of N and P likely overwhelms within-river heterotrophic processing. We propose that the capability of streams and rivers to retain N and P may be improved by active stoichiometric rebalancing. Although autotrophic OC production contributes to heterotrophic rates substantial control on nutrient processing from allochthonous OC is documented for N and an emerging field for P. Hence, rebalancing should be done by reconnecting appropriate OC sources such as wetlands and riparian forests that have become disconnected from rivers concurrent with agriculture and urbanisation. However, key knowledge gaps require research prior to the safe implementation of this approach in management: (i) to evaluate system responses to catchment inputs of dissolved OC forms and amounts relative to internal production of autotrophic dissolved OC and aquatic and terrestrial particulate OC and (ii) evaluate risk factors in anoxia-mediated P desorption with elevated OC scenarios. Still, we find stoichiometric rebalancing through reconnecting landscape beneficial OC sources has considerable potential for river management to alleviate eutrophication, improve water quality and aquatic ecosystem health, if augmenting nutrient source control. Copyright © 2018 Elsevier B.V. All rights reserved.

Dominance, biomass and extinction resistance determine the consequences of biodiversity loss for multiple coastal ecosystem processes.

PubMed

Davies, Thomas W; Jenkins, Stuart R; Kingham, Rachel; Kenworthy, Joseph; Hawkins, Stephen J; Hiddink, Jan G

2011-01-01

Key ecosystem processes such as carbon and nutrient cycling could be deteriorating as a result of biodiversity loss. However, currently we lack the ability to predict the consequences of realistic species loss on ecosystem processes. The aim of this study was to test whether species contributions to community biomass can be used as surrogate measures of their contribution to ecosystem processes. These were gross community productivity in a salt marsh plant assemblage and an intertidal macroalgae assemblage; community clearance of microalgae in sessile suspension feeding invertebrate assemblage; and nutrient uptake in an intertidal macroalgae assemblage. We conducted a series of biodiversity manipulations that represented realistic species extinction sequences in each of the three contrasting assemblages. Species were removed in a subtractive fashion so that biomass was allowed to vary with each species removal, and key ecosystem processes were measured at each stage of community disassembly. The functional contribution of species was directly proportional to their contribution to community biomass in a 1:1 ratio, a relationship that was consistent across three contrasting marine ecosystems and three ecosystem processes. This suggests that the biomass contributed by a species to an assemblage can be used to approximately predict the proportional decline in an ecosystem process when that species is lost. Such predictions represent "worst case scenarios" because, over time, extinction resilient species can offset the loss of biomass associated with the extinction of competitors. We also modelled a "best case scenario" that accounts for compensatory responses by the extant species with the highest per capita contribution to ecosystem processes. These worst and best case scenarios could be used to predict the minimum and maximum species required to sustain threshold values of ecosystem processes in the future.

Dominance, Biomass and Extinction Resistance Determine the Consequences of Biodiversity Loss for Multiple Coastal Ecosystem Processes

PubMed Central

Davies, Thomas W.; Jenkins, Stuart R.; Kingham, Rachel; Kenworthy, Joseph; Hawkins, Stephen J.; Hiddink, Jan G.

2011-01-01

Key ecosystem processes such as carbon and nutrient cycling could be deteriorating as a result of biodiversity loss. However, currently we lack the ability to predict the consequences of realistic species loss on ecosystem processes. The aim of this study was to test whether species contributions to community biomass can be used as surrogate measures of their contribution to ecosystem processes. These were gross community productivity in a salt marsh plant assemblage and an intertidal macroalgae assemblage; community clearance of microalgae in sessile suspension feeding invertebrate assemblage; and nutrient uptake in an intertidal macroalgae assemblage. We conducted a series of biodiversity manipulations that represented realistic species extinction sequences in each of the three contrasting assemblages. Species were removed in a subtractive fashion so that biomass was allowed to vary with each species removal, and key ecosystem processes were measured at each stage of community disassembly. The functional contribution of species was directly proportional to their contribution to community biomass in a 1∶1 ratio, a relationship that was consistent across three contrasting marine ecosystems and three ecosystem processes. This suggests that the biomass contributed by a species to an assemblage can be used to approximately predict the proportional decline in an ecosystem process when that species is lost. Such predictions represent “worst case scenarios” because, over time, extinction resilient species can offset the loss of biomass associated with the extinction of competitors. We also modelled a “best case scenario” that accounts for compensatory responses by the extant species with the highest per capita contribution to ecosystem processes. These worst and best case scenarios could be used to predict the minimum and maximum species required to sustain threshold values of ecosystem processes in the future. PMID:22163297

Mass loss and nutrient concentrations of buried wood as a function of organic matter removal, soil compaction, and vegetation control in a regenerating oak-pine forest

Treesearch

Felix Ponder; John M. Kabrick; Mary Beth Adams; Deborah S. Page-Dumroese; Marty F. Jurgensen

2017-01-01

Mass loss and nutrient concentrations of northern red oak (Quercus rubra) and white oak (Q. alba) wood stakes were measured 30 months after their burial in the upper 10 cm of soil in a regenerating forest after harvesting and soil disturbance. Disturbance treatments were two levels of organic matter (OM) removal (only...

Comparative Emergy Evaluation of Nutrient Removal and Nutrient Recovery Technologies and the Implications to Nutrient Management

EPA Science Inventory

The urbanization of the modern community creates large population centers that generate concentrated wastewater. A large expenditure on wastewater treatment has to be invested to make a modern city function without human and environmental health problems. Society relies on syste...

Growth, morphometrics and nutrient content of farmed eastern oysters, Crassostrea virginica (Gmelin), in New Hampshire, USA

EPA Science Inventory

When harvested, oysters represent a removal from the ecosystem of nutrients such as nitrogen (N)and carbon (C). A number of factors potentially affect nutrient content, but a quantitative understanding across the geographical range of the eastern oysters is lacking. This study wa...

Biomass production and nutrient removal by switchgrass under irrigation

USDA-ARS?s Scientific Manuscript database

Switchgrass has been identified to supply a major portion of U.S. energy needs when used as a fuel. Assessments of the export of essential plant nutrients are needed to determine impacts on soil fertility that will influence fertilizer recommendations since the nutrients contained in the above groun...

Long-term trends in nutrient budgets of the western Dutch Wadden Sea (1976-2012)

NASA Astrophysics Data System (ADS)

Jung, A. S.; Brinkman, A. G.; Folmer, E. O.; Herman, P. M. J.; van der Veer, H. W.; Philippart, C. J. M.

2017-09-01

Long-term field observations of nitrogen [N] and phosphorus [P] concentrations were used to construct nutrient budgets for the western Dutch Wadden Sea between 1976 and 2012. Nutrients come into the western Dutch Wadden Sea via river runoff, through exchange with the coastal zone of the North Sea, neighbouring tidal basins and through atmospheric deposition (for N). The highest concentrations in phosphorus and nitrogen were observed in the mid-1980s. Improved phosphorus removal at waste water treatment plants, management of fertilization in agriculture and removal of phosphates from detergents led to reduced riverine nutrient inputs and, consequently, reduced nutrient concentrations in the Wadden Sea. The budgets suggest that the period of the initial net import of phosphorus and nitrogen switched to a net export in 1981 for nitrogen and in 1992 for phosphorus. Such different behaviour in nutrient budgets during the rise and fall of external nutrient concentrations may be the result of different sediment-water exchange dynamics for P and N. It is hypothesized that during the period of increasing eutrophication (1976-1981) P, and to a lesser degree N, were stored in sediments as organic and inorganic nutrients. In the following period (1981-1992) external nutrient concentrations (especially in the North Sea) decreased, but P concentrations in the Wadden Sea remained high due to prolonged sediment release, whilst denitrification removed substantial amounts of N. From 1992 onwards, P and N budgets were closed by net loss, most probably because P stores were then depleted and denitrification continued. Under the present conditions (lower rates of sediment import and depleted P stores), nutrient concentrations in this area are expected to be more strongly influenced by wind-driven exchange with the North Sea and precipitation-driven discharge from Lake IJssel. This implies that the consequences of climate change will be more important, than during the 1970s and 1980s.

Metal removal from oil sands tailings pond water by indigenous micro-alga.

PubMed

Mahdavi, Hamed; Ulrich, Ania C; Liu, Yang

2012-09-01

This paper reports the removal of ten target metals of environmental concern ((53)Cr, Mn, Co, (60)Ni, (65)Cu, (66)Zn, As, (88)Sr, (95)Mo, and Ba) from oil sands tailings pond water. The organism responsible for removal was found to be an indigenous green micro-alga identified as Parachlorella kessleri by sequencing of the 23S rRNA gene. P. kessleri grew in tailings pond water samples taken from two oil sands operators (Syncrude Canada Ltd. and Albian Sands Energy Inc.), and enriched with low (0.24 mM NO(3)(-) and 0.016 mM PO(4)(-3)) and high (1.98 mM NO(3)(-) and 0.20mM PO(4)(-3)) concentrations of nutrient supplements (the most realistic scenario). The removal of (60)Ni, (65)Cu, As, (88)Sr, (95)Mo, and Ba from Syncrude tailings pond water was significantly enhanced by high concentrations of nitrogen and phosphorus, whereas the high nutrient concentrations adversely affected the removal of Co, (60)Ni, As, (88)Sr, and Mo in samples of Albian tailings pond water. Based on ANOVA two-factor analysis, higher nutrient concentration does not always result in higher metal removal, and TPW source must also be considered. Copyright © 2012. Published by Elsevier Ltd.

Effect of nitrogen and phosphorus concentration on their removal kinetic in treated urban wastewater by Chlorella vulgaris.

PubMed

Ruiz, J; Alvarez, P; Arbib, Z; Garrido, C; Barragán, J; Perales, J A

2011-10-01

This study evaluates the feasibility of removing nutrients by the microalgae Chlorella vulgaris, using urban wastewater as culture medium, namely the effluent subjected to secondary biological treatment in a wastewater treatment plant (WWTP). For this, laboratory experiments were performed in batch cultures to study the effect of initial nitrogen and phosphorus concentrations on growth and reduction of nutrient performance of C. vulgaris. The microalga was cultivated in enriched wastewater containing different phosphorus (1.3-143.5 mg x L(-1) P.PO4(3-)), ammonium (5.8-226.8 mg x L(-1) N-NH4+) and nitrate (1.5-198.3 mg x L(-1) N-NO3-) concentrations. The nutrient removal and growth kinetics have been studied: maximum productivity of 0.95 g SS x L(-1) x day(-1), minimum yield factor for cells on substrate (Y) of 11.51 g cells x g nitrogen(-1) and 0.04 g cells x g phosphorus(-1) were observed. The results suggested that C. vulgaris has a high potential to reduce nutrients in secondary WWTP effluents.

A study on the optimal hydraulic loading rate and plant ratios in recirculation aquaponic system.

PubMed

Endut, Azizah; Jusoh, A; Ali, N; Wan Nik, W B; Hassan, A

2010-03-01

The growths of the African catfish (Clarias gariepinus) and water spinach (Ipomoea aquatica) were evaluated in recirculation aquaponic system (RAS). Fish production performance, plant growth and nutrient removal were measured and their dependence on hydraulic loading rate (HLR) was assessed. Fish production did not differ significantly between hydraulic loading rates. In contrast to the fish production, the water spinach yield was significantly higher in the lower hydraulic loading rate. Fish production, plant growth and percentage nutrient removal were highest at hydraulic loading rate of 1.28 m/day. The ratio of fish to plant production has been calculated to balance nutrient generation from fish with nutrient removal by plants and the optimum ratio was 15-42 gram of fish feed/m(2) of plant growing area. Each unit in RAS was evaluated in terms of oxygen demand. Using specified feeding regime, mass balance equations were applied to quantify the waste discharges from rearing tanks and treatment units. The waste discharged was found to be strongly dependent on hydraulic loading rate. 2009 Elsevier Ltd. All rights reserved.

BANR: A Program to Predict Biomass Yield and Nutrient Withdrawal by Harvest of Southern Hardwood Stands

Treesearch

John K. Francis

1986-01-01

Intensive harvest of southern hardwoods can yield biomass in a greatly varied mix. This causes variation in the withdrawal rates of nutrients. A need exists for a computer program to perform biomass and nutrient content calculations on diverse stands. such a program BANR (Biomass And Nutrient Removal) - is described in this paper. It was written for the Hewlett-Packard...

An anaerobic membrane bioreactor - membrane distillation hybrid system for energy recovery and water reuse: Removal performance of organic carbon, nutrients, and trace organic contaminants.

PubMed

Song, Xiaoye; Luo, Wenhai; McDonald, James; Khan, Stuart J; Hai, Faisal I; Price, William E; Nghiem, Long D

2018-07-01

In this study, a direct contact membrane distillation (MD) unit was integrated with an anaerobic membrane bioreactor (AnMBR) to simultaneously recover energy and produce high quality water for reuse from wastewater. Results show that AnMBR could produce 0.3-0.5L/g COD added biogas with a stable methane content of approximately 65%. By integrating MD with AnMBR, bulk organic matter and phosphate were almost completely removed. The removal of the 26 selected trace organic contaminants by AnMBR was compound specific, but the MD process could complement AnMBR removal, leading to an overall efficiency from 76% to complete removal by the integrated system. The results also show that, due to complete retention, organic matter (such as humic-like and protein-like substances) and inorganic salts accumulated in the MD feed solution and therefore resulted in significant fouling of the MD unit. As a result, the water flux of the MD process decreased continuously. Nevertheless, membrane pore wetting was not observed throughout the operation. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Application of food waste disposers and alternate cycles process in small-decentralized towns: a case study.

PubMed

Battistoni, Paolo; Fatone, Francesco; Passacantando, Daniele; Bolzonella, David

2007-02-01

The use of food waste disposers (FWDs) can be an interesting option to integrate the management of municipal wastewaters and household organic waste in small towns and decentralized areas. This strategy can be even more environmentally friendly if a suitable treatment process of the resulting sewage is performed in order to control nutrients emission. However, still nowadays, part of the scientific and technical community considers the application of this technology a possible source of problems. In this study, the FWDs were applied, with a market penetration factor of 67%, in a mountain village of 250 inhabitants. Further, the existing wastewater treatment plant (WWTP) was upgraded by applying an automatically controlled alternate cycles process for the management of nutrients removal. With specific reference to the observed results, the impact of the ground food waste on the sewerage system did not show particular solids sedimentation or significant hydraulic overflows. Further, the WWTP was able to face the overloads of 11, 55 and 2g per capita per day of TSS, COD and TN, respectively. Then, the increase of the readily biodegradable COD (rbCOD/COD from 0.20 to 0.25) and the favourable COD/TN ratio (from 9.9 to 12) led to a specific denitrification rate of some 0.06kgNO(3)-N/(kg MLVSS day). Therefore, not only COD removal, but also the total nitrogen removal increased: the denitrification efficiency reached 85%. That led to a better exploitation of the nitrogen-bound oxygen and a consequent reduction of energy requirements of 39%. The final economic evaluation showed the benefits of the application of this technology with a pay back time of 4-5 years.

Effect of hydraulic retention time on inorganic nutrient recovery and biodegradable organics removal in a biofilm reactor treating plant biomass leachate

NASA Technical Reports Server (NTRS)

Krumins, Valdis; Hummerick, Mary; Levine, Lanfang; Strayer, Richard; Adams, Jennifer L.; Bauer, Jan

2002-01-01

A fixed-film (biofilm) reactor was designed and its performance was determined at various retention times. The goal was to find the optimal retention time for recycling plant nutrients in an advanced life support system, to minimize the size, mass, and volume (hold-up) of a production model. The prototype reactor was tested with aqueous leachate from wheat crop residue at 24, 12, 6, and 3 h hydraulic retention times (HRTs). Biochemical oxygen demand (BOD), nitrates and other plant nutrients, carbohydrates, total phenolics, and microbial counts were monitored to characterize reactor performance. BOD removal decreased significantly from 92% at the 24 h HRT to 73% at 3 h. Removal of phenolics was 62% at the 24 h retention time, but 37% at 3 h. Dissolved oxygen concentrations, nitric acid consumption, and calcium and magnesium removals were also affected by HRT. Carbohydrate removals, carbon dioxide (CO2) productions, denitrification, potassium concentrations, and microbial counts were not affected by different retention times. A 6 h HRT will be used in future studies to determine the suitability of the bioreactor effluent for hydroponic plant production.

Context-dependency in the effects of nutrient loading and consumers on the availability of space in marine rocky environments.

PubMed

Bulleri, Fabio; Russell, Bayden D; Connell, Sean D

2012-01-01

Enhanced nutrient loading and depletion of consumer populations interact to alter the structure of aquatic plant communities. Nonetheless, variation between adjacent habitats in the relative strength of bottom-up (i.e. nutrients) versus top-down (i.e. grazing) forces as determinants of community structure across broad spatial scales remains unexplored. We experimentally assessed the importance of grazing pressure and nutrient availability on the development of macroalgal assemblages and the maintenance of unoccupied space in habitats differing in physical conditions (i.e. intertidal versus subtidal), across regions of contrasting productivity (oligotrophic coasts of South Australia versus the more productive coasts of Eastern Australia). In Eastern Australia, grazers were effective in maintaining space free of macroalgae in both intertidal and subtidal habitats, irrespective of nutrient levels. Conversely, in South Australia, grazers could not prevent colonization of space by turf-forming macroalgae in subtidal habitats regardless of nutrients levels, yet in intertidal habitats removal of grazers reduced unoccupied space when nutrients were elevated. Assessing the effects of eutrophication in coastal waters requires balancing our understanding between local consumer pressure and background oceanographic conditions that affect productivity. This broader-based understanding may assist in reconciling disproportionately large local-scale variation, a characteristic of ecology, with regional scale processes that are often of greater relevance to policy making and tractability to management.

A Potential Waste to be Selected as Media for Metal and Nutrient Removal

NASA Astrophysics Data System (ADS)

Zayadi, N.; Othman, N.; Hamdan, R.

2016-07-01

This study describes the potential of application of cassava peel, banana peel, coconut shell, and coconut coir to be selected as metal removal while limestone and steel slag for nutrient removal. The media were characterized by X-Ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), Field Emission Scanning Electron Microscopy-Energy Dispersive X-Ray (FESEM-EDX), and X-Ray Powder Diffraction (XRD). The results of XRF analysis medias show the present of calcium oxide, CaO which confirm the high efficiency in adsorbing metal ions and nutrient which is in agreement with the result of XRD. The characteristics of medias by FTIR analysis also confirmed the involvement of alcohol, carboxylic, alkanes, amines and ethers which play important role to reduce ions while FESEM-EDX indicates the porous structures of study medias. The characterization analysis highlight that cassava peel and steel slag were selected as a potential media in this study.

Nutrient Removal from Wastewater Using Microalgae: A Kinetic Evaluation and Lipid Analysis.

PubMed

Babu, Anjana; Katam, Keerthi; Gundupalli, Marttin Paulraj; Bhattacharyya, Debraj

2018-06-01

  The objective of this study was to examine the performance of mixed microalgal bioreactors in treating three different types of wastewaters-kitchen wastewater (KWW), palm oil mill effluent (POME), and pharmaceutical wastewater (PWW) in semi-continuous mode and to analyze the lipid content in the harvested algal biomass. The reactors were monitored for total nitrogen and phosphate removal at eight solid retention times (SRTs): 2, 4, 6, 8, 10, 12, 14, and 16 days. The nutrient uptake kinetic parameters were quantified using linearized Michaelis-Menten and Monod models at steady-state conditions. The nutrient removal efficiency and lipid production were found to be higher in KWW when compared with the other wastewaters. Saturated fatty acids (C16:0, C18:0, and C18:1) accounted for more than 60% of the algal fatty acids for all the wastewaters. The lipid is, therefore, considered suitable for synthesizing biodiesel.

Effects of filtration modes on membrane fouling behavior and treatment in submerged membrane bioreactor.

PubMed

Maqbool, Tahir; Khan, Sher Jamal; Lee, Chung-Hak

2014-11-01

Relaxation or backwashing is obligatory for effective operation of membrane module and intermittent aeration is helpful for nutrients removal. This study was performed to investigate effects of different filtration modes on membrane fouling behavior and treatment in membrane bioreactor (MBR) operated at three modes i.e., 12, 10 and 8min filtration and 3, 2, and 2min relaxation corresponding to 6, 5 and 4cycles/hour, respectively. Various parameters including trans-membrane pressure, specific cake resistance, specific oxygen uptake rate, nutrients removal and sludge dewaterability were examined to optimize the filtration mode. TMP profiles showed that MBR(8+2) with 8min filtration and 2min relaxation reduced the fouling rate and depicted long filtration time in MBR treating synthetic wastewater. MBR(12+3) was more efficient in organic and nutrients removal while denitrification rate was high in MBR(8+2). Copyright © 2014 Elsevier Ltd. All rights reserved.

Potential Water Reuse for High Strength Fruit and Vegetable Processor Wastewater with an MBR.

PubMed

Moore, Adam W; Zytner, Richard G; Chang, Sheng

  High strength food processing wastewater from two processing plants was studied to determine the effectiveness of an aerobic membrane bioreactor (MBR) to reduce BOD, TSS and nutrients below municipal sewer discharge limits. The MBR comprised a 20 L lab-scale reactor combined with a flat sheet, ultrafiltration membrane module. The parameters studied included the operational flux, solids and hydraulic retention times and recirculation ratio with regards to nitrification/denitrification. The MBR system provided excellent removal efficiency at 97% COD, 99% BOD, 99.9% TSS, 90% TKN, and 60% TP for both processing plants, which eliminated the surcharges, allowing the firms to stay competitive. Effluent reuse tests showed that activated carbon proved effective in removing color from the MBR permeate, while UV treatment was able to achieve a 5 log reduction in bacteriophage. Overall, these treatment successes show the potential for water reuse in the agrifood sector.

Biomass removal and its effect on productivity of an artificially regenerated forest stand in the Missouri ozarks

Treesearch

Flex Jr. Ponder

2007-01-01

Intensive harvesting, which removes a greater proportion of the forest biomass than conventional harvesting and the associated nutrients, may cause a decline in forest productivity. Planted seedling response to three biomass removal levels (1. removal of boles only=OM1, 2. all surface organic matter removed, forest floor not removed=OM2, and 3. removal of all surface...

Utilization of the water soluable fraction of wheat straw as a plant nutrient source

NASA Technical Reports Server (NTRS)

Mackowiak, C. L.; Garland, J. L.

1990-01-01

Recovery of water soluble, inorganic nutrients from the inedible portion of wheat was found to be an effective means of recycling nutrients within hydroponic systems. Through aqueous extraction (leaching), 60 percent of the total inorganic nutrient weight was removed from wheat straw and roots, although the recovery of individual nutrients varied. Leaching also removed about 20 percent of the total organic carbon from the biomass. In terms of dry weight, the leachate was comprised of approximately 60 percent organic and 40 percent inorganic compounds. Direct use of wheat straw leachate in static hydroponic systems had an inhibitory effect on wheat growth, both in the presence and absence of microorganisms. Biological treatment of leachate either with a mixed microbial community or the oyster mushroom Pleurotus ostreatus L., prior to use in hydroponic solutions, significantly reduced both the organic content and the inhibitory effects of the leachate. The inhibitory effects of unprocessed leachate appear to be a result of rapidly acting phytotoxic compounds that are detoxified by microbial activity. Leaching holds considerable promise as a method for nutrient recycling in a Controlled Ecological Life Support System (CELSS).

Copper import in Escherichia coli by the yersiniabactin metallophore system

PubMed Central

Koh, Eun-Ik; Robinson, Anne E.; Bandara, Nilantha; Rogers, Buck E.; Henderson, Jeffrey P.

2017-01-01

Copper plays a dual role as nutrient and toxin during bacterial infections. While uropathogenic Escherichia coli (UPEC) strains can use the copper-binding metallophore yersiniabactin (Ybt) to resist copper toxicity, Ybt also converts bioavailable copper to Cu(II)-Ybt in low copper conditions. Although E. coli have long been considered to lack a copper import pathway, we observed Ybt-mediated copper import in UPEC using canonical Fe(III)-Ybt transport proteins. UPEC removed copper from Cu(II)-Ybt with subsequent re-export of metal-free Ybt to the extracellular space. Copper released through this process became available to an E. coli cuproenzyme (the amine oxidase TynA), linking this import pathway to a nutrient acquisition function. Ybt-expressing E. coli thus engage in nutritional passivation, a strategy of minimizing a metal ion's toxicity while preserving its nutritional availability. Copper acquisition through this process may contribute to the marked virulence defect of Ybt transport-deficient UPEC. PMID:28759019

Role of modern climate and hydrology in world oil preservation

NASA Astrophysics Data System (ADS)

Szatmari, Peter

1992-12-01

The accumulation of oil requires a favorable source, a reservoir, good seal-rock quality, and suitably timed thermal history and structuring. The accumulated oil, especially its light fractions, may be subsequently removed by hydrologically controlled processes such as water washing, biodegradation, and tilting of the oil-water contact. These processes are dependent on the climate. In regions that have become increasingly cold or dry during late Cenozoic time, low rainfall, low ground-water flow rates, and low input of nutrients and microorganisms have protected the oil; in warm or temperate rainy climates, high flow rates and high input of nutrients and microorganisms have led to partial or total removal of oil. Thus, most of the rich (>500 000 barrels/day) oil provinces on land are in cold or dry regions, where water is recharged in highlands that receive little rain (<500 mm/yr), such as Texas, Oklahoma, Wyoming, Alaska's North Slope, California, Algeria, Libya, Egypt, the Middle East, the Volga-Ural basin, and western Siberia. Where upland recharge areas are warm or temperate and rainy, as in the eastern United States, western Europe, sub-Saharan Africa, Brazil, India, and most of China, rich oil provinces on land (outside young deltas) are rare, and biodegradation is widespread.

Exploitation of Trametes versicolor for bioremediation of endocrine disrupting chemicals in bioreactors

PubMed Central

Sannia, Giovanni; Raganati, Francesca; Olivieri, Giuseppe; Marzocchella, Antonio; Schlosser, Dietmar

2017-01-01

Endocrine disrupting chemicals (EDCs) are environmental contaminants causing increasing concerns due to their toxicity, persistence and ubiquity. In the present study, degradative capabilities of Trametes versicolor, Pleurotus ostreatus and Phanerochaete chrysosporium to act on five EDCs, which represent different classes of chemicals (phenols, parabens and phthalate) and were first applied as single compounds, were assessed. T. versicolor was selected due to its efficiency against target EDCs and its potentialities were exploited against a mixture of EDCs in a cost-effective bioremediation process. A fed-batch approach as well as a starvation strategy were applied in order to reduce the need for input of ‘fresh’ biomass, and avoid the requirement for external nutrients. The fungus was successfully operated in two different bioreactors over one week. Semi-batch cultures were carried out by daily adding a mixture of EDCs to the bioreactors in a total of five consecutive degradation cycles. T. versicolor was able to efficiently remove all compounds during each cycle converting up to 21 mg L-1 day-1 of the tested EDCs. The maintained ability of T. versicolor to remove EDCs without any additional nutrients represents the main outcome of this study, which enables to forecast its application in a water treatment process. PMID:28575092

Exploitation of Trametes versicolor for bioremediation of endocrine disrupting chemicals in bioreactors.

PubMed

Pezzella, Cinzia; Macellaro, Gemma; Sannia, Giovanni; Raganati, Francesca; Olivieri, Giuseppe; Marzocchella, Antonio; Schlosser, Dietmar; Piscitelli, Alessandra

2017-01-01

Endocrine disrupting chemicals (EDCs) are environmental contaminants causing increasing concerns due to their toxicity, persistence and ubiquity. In the present study, degradative capabilities of Trametes versicolor, Pleurotus ostreatus and Phanerochaete chrysosporium to act on five EDCs, which represent different classes of chemicals (phenols, parabens and phthalate) and were first applied as single compounds, were assessed. T. versicolor was selected due to its efficiency against target EDCs and its potentialities were exploited against a mixture of EDCs in a cost-effective bioremediation process. A fed-batch approach as well as a starvation strategy were applied in order to reduce the need for input of 'fresh' biomass, and avoid the requirement for external nutrients. The fungus was successfully operated in two different bioreactors over one week. Semi-batch cultures were carried out by daily adding a mixture of EDCs to the bioreactors in a total of five consecutive degradation cycles. T. versicolor was able to efficiently remove all compounds during each cycle converting up to 21 mg L-1 day-1 of the tested EDCs. The maintained ability of T. versicolor to remove EDCs without any additional nutrients represents the main outcome of this study, which enables to forecast its application in a water treatment process.

Removal of an apex predator initiates a trophic cascade that extends from herbivores to vegetation and the soil nutrient pool

PubMed Central

2017-01-01

It is widely assumed that organisms at low trophic levels, particularly microbes and plants, are essential to basic services in ecosystems, such as nutrient cycling. In theory, apex predators' effects on ecosystems could extend to nutrient cycling and the soil nutrient pool by influencing the intensity and spatial organization of herbivory. Here, we take advantage of a long-term manipulation of dingo abundance across Australia's dingo-proof fence in the Strzelecki Desert to investigate the effects that removal of an apex predator has on herbivore abundance, vegetation and the soil nutrient pool. Results showed that kangaroos were more abundant where dingoes were rare, and effects of kangaroo exclusion on vegetation, and total carbon, total nitrogen and available phosphorus in the soil were marked where dingoes were rare, but negligible where dingoes were common. By showing that a trophic cascade resulting from an apex predator's lethal effects on herbivores extends to the soil nutrient pool, we demonstrate a hitherto unappreciated pathway via which predators can influence nutrient dynamics. A key implication of our study is the vast spatial scale across which apex predators' effects on herbivore populations operate and, in turn, effects on the soil nutrient pool and ecosystem productivity could become manifest. PMID:28490624

Rain forest nutrient cycling and productivity in response to large-scale litter manipulation.

PubMed

Wood, Tana E; Lawrence, Deborah; Clark, Deborah A; Chazdon, Robin L

2009-01-01

Litter-induced pulses of nutrient availability could play an important role in the productivity and nutrient cycling of forested ecosystems, especially tropical forests. Tropical forests experience such pulses as a result of wet-dry seasonality and during major climatic events, such as strong El Niños. We hypothesized that (1) an increase in the quantity and quality of litter inputs would stimulate leaf litter production, woody growth, and leaf litter nutrient cycling, and (2) the timing and magnitude of this response would be influenced by soil fertility and forest age. To test these hypotheses in a Costa Rican wet tropical forest, we established a large-scale litter manipulation experiment in two secondary forest sites and four old-growth forest sites of differing soil fertility. In replicated plots at each site, leaves and twigs (< 2 cm diameter) were removed from a 400-m2 area and added to an adjacent 100-m2 area. This transfer was the equivalent of adding 5-25 kg/ha of organic P to the forest floor. We analyzed leaf litter mass, [N] and [P], and N and P inputs for addition, removal, and control plots over a two-year period. We also evaluated basal area increment of trees in removal and addition plots. There was no response of forest productivity or nutrient cycling to litter removal; however, litter addition significantly increased leaf litter production and N and P inputs 4-5 months following litter application. Litter production increased as much as 92%, and P and N inputs as much as 85% and 156%, respectively. In contrast, litter manipulation had no significant effect on woody growth. The increase in leaf litter production and N and P inputs were significantly positively related to the total P that was applied in litter form. Neither litter treatment nor forest type influenced the temporal pattern of any of the variables measured. Thus, environmental factors such as rainfall drive temporal variability in litter and nutrient inputs, while nutrient release from decomposing litter influences the magnitude. Seasonal or annual variation in leaf litter mass, such as occurs in strong El Niño events, could positively affect leaf litter nutrient cycling and forest productivity, indicating an ability of tropical trees to rapidly respond to increased nutrient availability.

Impact of hazardous events on the removal of nutrients and trace organic contaminants by an anoxic-aerobic membrane bioreactor receiving real wastewater.

PubMed

Phan, Hop V; Hai, Faisal I; McDonald, James A; Khan, Stuart J; van de Merwe, Jason P; Leusch, Frederic D L; Zhang, Ren; Price, William E; Broeckmann, Andreas; Nghiem, Long D

2015-09-01

The impacts of four simulated hazardous events, namely, aeration failure, power loss, and chemical shocks (ammonia or bleach) on the performance of an anoxic-aerobic membrane bioreactor (MBR) receiving real wastewater were investigated. Hazardous events could alter pH and/or oxidation reduction potential of the mixed liquor and inhibit biomass growth, thus affecting the removal of bulk organics, nutrients and trace organic contaminants (TrOC). Chemical shocks generally exerted greater impact on MBR performance than aeration/power failure events, with ammonia shock exerting the greatest impact. Compared to total organic carbon, nutrient removal was more severely affected. Removal of the hydrophilic TrOCs that are resistant and/or occur at high concentrations in wastewater was notably affected. The MBR effectively reduced estrogenicity and toxicity from wastewater, but chemical shocks could temporarily increase the endocrine activity of the effluent. Depending on the chemical shock-dose and the membrane flux, hazardous events can exacerbate membrane fouling. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dissolved inorganic carbon enhanced growth, nutrient uptake, and lipid accumulation in wastewater grown microalgal biofilms.

PubMed

Kesaano, Maureen; Gardner, Robert D; Moll, Karen; Lauchnor, Ellen; Gerlach, Robin; Peyton, Brent M; Sims, Ronald C

2015-03-01

Microalgal biofilms grown to evaluate potential nutrient removal options for wastewaters and feedstock for biofuels production were studied to determine the influence of bicarbonate amendment on their growth, nutrient uptake capacity, and lipid accumulation after nitrogen starvation. No significant differences in growth rates, nutrient removal, or lipid accumulation were observed in the algal biofilms with or without bicarbonate amendment. The biofilms possibly did not experience carbon-limited conditions because of the large reservoir of dissolved inorganic carbon in the medium. However, an increase in photosynthetic rates was observed in algal biofilms amended with bicarbonate. The influence of bicarbonate on photosynthetic and respiration rates was especially noticeable in biofilms that experienced nitrogen stress. Medium nitrogen depletion was not a suitable stimulant for lipid production in the algal biofilms and as such, focus should be directed toward optimizing growth and biomass productivities to compensate for the low lipid yields and increase nutrient uptake. Copyright © 2015 Elsevier Ltd. All rights reserved.

An Innovative Design of a Clay-Zeolite Medium for the Adsorption of Total Phosphorus from Wastewater.

PubMed

Ciosek, Amanda Lidia; Luk, Grace K; Warner, Michèle; Warner, R Anthony

2016-02-01

Phosphorus significantly influences the eutrophication process, modifying the quality of waterways and habitat, especially in stagnant waterbodies exposed to septic tank effluent at high nutrient levels. This research explores the development of a cost-effective, efficient, and affordable on-site wastewater treatment system targeted as total phosphorus (TP) removal technology. The research objective is to demonstrate the TP removal efficiency of an optimized clay-zeolite medium by chemical adsorption. The study observes the effects of pellet medium design and modifications, influent concentrations, and contact time. Following various stages of optimization, the preliminary testing achieves a 45 ± 1.8% removal after 45 minutes of contact time. The optimized pellets are contained within a five-layer bench-scale model, achieving equilibrium TP removal of 72 ± 2.9% after 3 hours. Theoretical extrapolation to 12 contact hours indicates an achievement of 88% removal is possible. The results show a positive correlation with the linearized Langmuir and Freundlich adsorption isotherms.

Material and method for promoting the growth of anaerobic bacteria

DOEpatents

Adler, H.I.

1984-10-09

A material and method is disclosed for promoting the growth of anaerobic bacteria which includes a nutrient media containing a hydrogen donor and sterile membrane fragments of bacteria having an electron transfer system which reduces oxygen to water. Dissolved oxygen in the medium is removed by adding the sterile membrane fragments to the nutrient medium and holding the medium at a temperature of about 10 to about 60 C until the dissolved oxygen is removed. No Drawings

Material and method for promoting the growth of anaerobic bacteria

DOEpatents

Adler, Howard I.

1984-01-01

A material and method for promoting the growth of anaerobic bacteria which includes a nutrient media containing a hydrogen donor and sterile membrane fragments of bacteria having an electron transfer system which reduces oxygen to water. Dissolved oxygen in the medium is removed by adding the sterile membrane fragments to the nutrient medium and holding the medium at a temperature of about 10.degree. to about 60.degree. C. until the dissolved oxygen is removed.

Dry Matter Production, Nutrient Cycled and Removed, and Soil Fertility Changes in Yam-Based Cropping Systems with Herbaceous Legumes in the Guinea-Sudan Zone of Benin.

PubMed

Maliki, Raphiou; Sinsin, Brice; Floquet, Anne; Cornet, Denis; Malezieux, Eric; Vernier, Philippe

2016-01-01

Traditional yam-based cropping systems (shifting cultivation, slash-and-burn, and short fallow) often result in deforestation and soil nutrient depletion. The objective of this study was to determine the impact of yam-based systems with herbaceous legumes on dry matter (DM) production (tubers, shoots), nutrients removed and recycled, and the soil fertility changes. We compared smallholders' traditional systems (1-year fallow of Andropogon gayanus-yam rotation, maize-yam rotation) with yam-based systems integrated herbaceous legumes (Aeschynomene histrix/maize intercropping-yam rotation, Mucuna pruriens/maize intercropping-yam rotation). The experiment was conducted during the 2002 and 2004 cropping seasons with 32 farmers, eight in each site. For each of them, a randomized complete block design with four treatments and four replicates was carried out using a partial nested model with five factors: Year, Replicate, Farmer, Site, and Treatment. Analysis of variance (ANOVA) using the general linear model (GLM) procedure was applied to the dry matter (DM) production (tubers, shoots), nutrient contribution to the systems, and soil properties at depths 0-10 and 10-20 cm. DM removed and recycled, total N, P, and K recycled or removed, and soil chemical properties (SOM, N, P, K, and pH water) were significantly improved on yam-based systems with legumes in comparison with traditional systems.

Nature-based solutions for hydro-meteorological risk reduction and nutrient removal in the Nordic and Arctic regions

NASA Astrophysics Data System (ADS)

Bring, Arvid; Kalantari, Zahra

2017-04-01

Natural ecological functions provide essential and fundamental benefits to mankind, but can also be actively employed in nature-based solutions to specific challenges in society. For example, water-related ecosystem services have a role in such societal benefits as flood protection, erosion control, and excess nutrient removal. Ecosystem services may be produced and consumed in different locations, and research has recently attempted to formalize this discrepancy in identifying service providing areas (SPAs), service benefitting areas (SBAs), and service connecting areas (SCAs). However, in terms of water-related services, there is a lack of formal evaluation of how SPAs, SBAs, and SCAs are related to hydrological measures such as discharge, flood recurrence, excess nutrient removal, etc. We seek to map SPAs, SBAs and SCAs for a number of key ecosystem services in the Nordic and Arctic region though established ecological definitions (typically, based on land use) and evaluate the findings alongside metrics of hydrological connectivity (river networks), provisioning areas (runoff generating areas), and benefitting areas (river stretches where water flow is moderated). We make use of extensive GIS analysis using both high-resolution land cover data and river network maps. In the end, the results are expected to contribute to identifying how water-related ecosystem services can be employed as nature-based solutions for hydro-meteorological risk reduction and nutrient removal in a changing climate in the Nordic and Arctic regions.

Dry Matter Production, Nutrient Cycled and Removed, and Soil Fertility Changes in Yam-Based Cropping Systems with Herbaceous Legumes in the Guinea-Sudan Zone of Benin

PubMed Central

Sinsin, Brice; Floquet, Anne; Cornet, Denis; Malezieux, Eric; Vernier, Philippe

2016-01-01

Traditional yam-based cropping systems (shifting cultivation, slash-and-burn, and short fallow) often result in deforestation and soil nutrient depletion. The objective of this study was to determine the impact of yam-based systems with herbaceous legumes on dry matter (DM) production (tubers, shoots), nutrients removed and recycled, and the soil fertility changes. We compared smallholders' traditional systems (1-year fallow of Andropogon gayanus-yam rotation, maize-yam rotation) with yam-based systems integrated herbaceous legumes (Aeschynomene histrix/maize intercropping-yam rotation, Mucuna pruriens/maize intercropping-yam rotation). The experiment was conducted during the 2002 and 2004 cropping seasons with 32 farmers, eight in each site. For each of them, a randomized complete block design with four treatments and four replicates was carried out using a partial nested model with five factors: Year, Replicate, Farmer, Site, and Treatment. Analysis of variance (ANOVA) using the general linear model (GLM) procedure was applied to the dry matter (DM) production (tubers, shoots), nutrient contribution to the systems, and soil properties at depths 0–10 and 10–20 cm. DM removed and recycled, total N, P, and K recycled or removed, and soil chemical properties (SOM, N, P, K, and pH water) were significantly improved on yam-based systems with legumes in comparison with traditional systems. PMID:27446635

The short-term effects of prescribed burning on biomass removal and the release of nitrogen and phosphorus in a treatment wetland.

PubMed

White, J R; Gardner, L M; Sees, M; Corstanje, R

2008-01-01

Nutrient removal by constructed wetlands can decline over time due to the accumulation of organic matter. A prescribed burn is one of many management strategies used to remove detritus in macrophyte-dominated systems. We quantified the short-term effects on effluent water quality and the amount of aboveground detritus removed from a prescribed burn event. Surface water outflow concentrations were approximately three times higher for P and 1.5 times higher for total Kjeldhal nitrogen (TKN) following the burn event when compared to the control. The length of time over which the fire effect was significant (P < 0.05), 3 d for TKN and up to 23 d for P fractions. Over time, the concentration of soluble reactive phosphorus (SRP) in the effluent decreased, but was compensated with increases in dissolved organic phosphorus (DOP) and particulate phosphorus (PP), such that net total P remained the same. Total aboveground biomass decreased by 68.5% as a result of the burn, however, much of the live vegetation was converted to standing dead material. These results demonstrate that a prescribed burn can significantly decrease the amount of senescent organic matter in a constructed wetland. However, short-term nutrient releases following the burn could increase effluent nutrient concentrations. Therefore, management strategies should include hydraulically isolating the burned area immediately following the burn event to prevent nutrient export.

Modeling of land use and reservoir effects on nonpoint source pollution in a highly agricultural basin

USGS Publications Warehouse

Wu, Yiping; Liu, Shu-Guang

2012-01-01

Nonpoint source (NPS) pollution is tightly linked to land use activities that determine the sources and magnitudes of pollutant loadings to stream water. The pollutant loads may also be alleviated within reservoirs because of the physical interception resulting from changed hydrological regimes and other biochemical processes. It is important but challenging to assess the NPS pollution processes with human effects due to the measurement limitations. The objective of this study is to evaluate the effects of human activities such as land uses and reservoir operation on the hydrological and NPS pollution processes in a highly agricultural area-the Iowa River Basin-using the Soil and Water Assessment Tool (SWAT). The evaluation of model performance at multiple sites reveals that SWAT can consistently simulate the daily streamflow, and monthly/annual sediment and nutrient loads (nitrate nitrogen and mineral phosphorus) in the basin. We also used the calibrated model to estimate the trap efficiencies of sediment (~78%) and nutrients (~30%) in the Coralville Reservoir within the basin. These non-negligible effects emphasize the significance of incorporating the sediment and nutrient removal mechanisms into watershed system studies. The spatial quantification of the critical NPS pollution loads can help identify hot-spot areas that are likely locations for the best management practices.

Modeling of land use and reservoir effects on nonpoint source pollution in a highly agricultural basin.

PubMed

Wu, Yiping; Liu, Shuguang

2012-09-01

Nonpoint source (NPS) pollution is tightly linked to land use activities that determine the sources and magnitudes of pollutant loadings to stream water. The pollutant loads may also be alleviated within reservoirs because of the physical interception resulting from changed hydrological regimes and other biochemical processes. It is important but challenging to assess the NPS pollution processes with human effects due to the measurement limitations. The objective of this study is to evaluate the effects of human activities such as land uses and reservoir operation on the hydrological and NPS pollution processes in a highly agricultural area-the Iowa River Basin-using the Soil and Water Assessment Tool (SWAT). The evaluation of model performance at multiple sites reveals that SWAT can consistently simulate the daily streamflow, and monthly/annual sediment and nutrient loads (nitrate nitrogen and mineral phosphorus) in the basin. We also used the calibrated model to estimate the trap efficiencies of sediment (∼78%) and nutrients (∼30%) in the Coralville Reservoir within the basin. These non-negligible effects emphasize the significance of incorporating the sediment and nutrient removal mechanisms into watershed system studies. The spatial quantification of the critical NPS pollution loads can help identify hot-spot areas that are likely locations for the best management practices.

Aerobic granulation in a sequencing batch reactor (SBR) for industrial wastewater treatment.

PubMed

Inizan, M; Freval, A; Cigana, J; Meinhold, J

2005-01-01

Aerobic granulation seems to be an a attractive process for COD removal from industrial wastewater, characterised by a high content of soluble organic compounds. In order to evaluate the practical aspects of the process, comparative experimental tests are performed on synthetic and on industrial wastewater, originating from pharmaceutical industry. Two pilot plants are operated as sequencing batch bubble columns. Focus was put on the feasibility of the process for high COD removal and on its operational procedure. For both wastewaters, a rapid formation of aerobic granules is observed along with a high COD removal rate. Granule characteristics are quite similar with respect to the two types of wastewater. It seems that filamentous bacteria are part of the granule structure and that phosphorus precipitation can play an important role in granule formation. For both wastewaters similar removal performances for dissolved biodegradable COD are observed (> 95%). However, a relatively high concentration of suspended solids in the outlet deteriorates the performance with regard to total COD removal. Biomass detachment seems to play a non-negligible role in the current set-up. After a stable operational phase the variation of the pharmaceutical wastewater caused a destabilisation and loss of the granules, despite the control for balanced nutrient supply. The first results with real industrial wastewater demonstrate the feasibility of this innovative process. However, special attention has to be paid to the critical aspects such as granule stability as well as the economic competitiveness, which both will need further investigation and evaluation.

Treatment of azo dye Acid Orange 52 using ozonation and completed-mixed activated sludge process

NASA Astrophysics Data System (ADS)

Abidin, C. Z. A.; Fahmi; Ong, S. A.; Ahmad, R.; Sabri, S. N.

2017-06-01

In this study, the characteristic of colour and COD removal of azo dye Acid Orange 52 (AO52) by ozonation, in combination with complete-mixed activated sludge process (CMAS) was evaluated. The experimentation was arranged in two phases: during the first one, only ozonation was performed, while, during the second phase, it was integrated with CMAS. The performance of colour and COD concentration of AO52 with and without CMAS treatment, is compared and evaluated. From the results, it is obvious that high decolourization from the start of CMAS was contributed from the pre-treatments. The colour removal was due to the fact that ozonation able to cleave the azo bonds that represent colour. Thus, CMAS without pre-treatment are unable to decolourize the dyes sufficiently. 59.6% COD was removed from the first-stage, while merely 9.8% COD fraction removed from the subsequence second-stage CMAS. It is suggested that the rapid COD removal without ozonation are due to activated sludge adsorption processes. The decreased of mixed liquor suspended solids (MLSS) affected the CMAS performances, as the biomass decreased due to lack of nutrient for activated sludge microorganisms to multiply. Results from pre-ozonation alone contributed more than 50% of total COD removal, which indicated that at higher ozone dosage, tend to mineralize azo dye. Thus, ozonation not oxidized the dye though complete mineralization that produce carbon dioxide and water. However, it is a potential process for enhancing colour removal and biodegradability of dye-containing wastewater, once the appropriate ozonation time is determined. Therefore, the role of ozonation seems to break down the dye molecules and created ozonation by-product that is easily biodegraded in the subsequent biological treatment.

Enhanced Removal of Nutrients and Trace Organics from Urban Runoff with Novel Capture, Treatment, and Recharge Systems

NASA Astrophysics Data System (ADS)

Ashoori, N.; Planes, M. T.; Lefevre, G.; Sedlak, D.; Luthy, R. G.

2017-12-01

Rapid population growth, urban sprawl and impact of climate change are forcing water-stressed areas to rely on new local sources of water supply. Under this scenario, reclamation of stormwater runoff has emerged as a source for irrigation and replenishing drinking-water groundwater reservoirs. However, urban stormwater can be a significant source of pollutants, including nutrients and organic compounds. In order to overcome the stormwater treatment system limitations, this project has developed a pilot-scale column system for passive treatment of infiltrated water using low-cost, low-energy geomedia. The objective was to provide guidance on the design and operation of systems for controlling nutrient and trace organic contaminant releases to surface waters. The work comprised of replicate column studies in the field to test stormwater treatment modules with various media, such as woodchips and biochar, using urban runoff from a watershed in Sonoma, California. Woodchip bioreactors host an endemic population of microorganisms that can be harnessed to biologically degrade nitrate. The columns amended with biochar enhance removal of organic pollutants present in stormwater through physicochemical processes (i.e., adsorption onto biochar) and biodegradation in the column through increasing retention time. The field columns were conditioned with stormwater for eight months before being spiked weekly with 50 ppb of representative trace organics. The key finding was the successful field demonstration of a novel treatment system for both the removal of nitrate and trace organics. Nitrogen removal was successful in all columns for the thirteen month experiment due to the woodchips being an effective source of carbon for denitrifying microorganisms to convert nitrate to nitrogen gases. As for the trace organics experiments, the results highlight an overall attenuation of the studied trace organic compounds by the columns containing woodchip and biochar throughout the five months of contaminant dosing. By developing a fundamental understanding of the mechanisms of contaminant removal in the laboratory and testing system performance at the test-bed scale, the project advances efforts to improve water quality and augment local water supplies through distributed capture, treatment, and recharge systems.

A novel osmosis membrane bioreactor-membrane distillation hybrid system for wastewater treatment and reuse.

PubMed

Nguyen, Nguyen Cong; Nguyen, Hau Thi; Chen, Shiao-Shing; Ngo, Huu Hao; Guo, Wenshan; Chan, Wen Hao; Ray, Saikat Sinha; Li, Chi-Wang; Hsu, Hung-Te

2016-06-01

A novel approach was designed to simultaneously enhance nutrient removal and reduce membrane fouling for wastewater treatment using an attached growth biofilm (AGB) integrated with an osmosis membrane bioreactor (OsMBR) system for the first time. In this study, a highly charged organic compound (HEDTA(3-)) was employed as a novel draw solution in the AGB-OsMBR system to obtain a low reverse salt flux, maintain a healthy environment for the microorganisms. The AGB-OsMBR system achieved a stable water flux of 3.62L/m(2)h, high nutrient removal of 99% and less fouling during a 60-day operation. Furthermore, the high salinity of diluted draw solution could be effectively recovered by membrane distillation (MD) process with salt rejection of 99.7%. The diluted draw solution was re-concentrated to its initial status (56.1mS/cm) at recovery of 9.8% after 6h. The work demonstrated that novel multi-barrier systems could produce high quality potable water from impaired streams. Copyright © 2016. Published by Elsevier Ltd.

Urban wastewater treatment by seven species of microalgae and an algal bloom: Biomass production, N and P removal kinetics and harvestability.

PubMed

Mennaa, Fatima Zahra; Arbib, Zouhayr; Perales, José Antonio

2015-10-15

This study evaluates the capacity of seven species and a Bloom of microalgae to grow in urban wastewater. Nutrient removal kinetics and biomass harvesting by means of centrifugation and coagulation-flocculation-sedimentation have been also tested. Results show that the best biomass productivities ranged from between 118 and 108 mgSS L(-1) d(-1) for the Bloom (Bl) and Scenedesmus obliquus (Sco). Regarding nutrient removal, microalgae were able to remove the total dissolved phosphorus and nitrogen concentrations by more than 80% and 87% respectively, depending on the species tested. The final total dissolved concentration of nitrogen and phosphorus in the culture media complies with the European Commission Directive 98/15/CE on urban wastewater treatment. Regarding harvesting, the results of coagulation-flocculation sedimentation using a 60 mg L(-1) dose of Ferric chloride were similar between species, exceeding the biomass removal efficiency by more than 90%. The results of centrifugation (time required to remove 90% of solids at 1000 rpm) were not similar between species, with the shortest time being 2.9 min for Sco, followed by the bloom (7.25 min). An overall analysis suggested that the natural bloom and Scenedesmus obliquus seem to be the best candidates to grow in pre-treated wastewater, according to their biomass production, nutrient removal capability and harvestability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of nutrient limitations by long-term fertilization decreases nocturnal water loss in savanna trees.

Treesearch

F.G. Scholz; S.J. Bucci; G. Goldstein; F.C. Meinzer; A.C. Franco; F. Miralles-Wilhelm

2007-01-01

Under certain environmental conditions, nocturnal transpiration can be relatively high in temperate and tropical woody species. In nutrient-poor systems such as the Brazilian Cerrado, nocturnal transpiration may enhance delivery of nutrients to roots. We compared nocturnal transpiration of three dominant Cerrado tree species growing in unfertilized plots and plots to...

Belowground legacies of Pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown.

PubMed

Dickie, Ian A; St John, Mark G; Yeates, Gregor W; Morse, Chris W; Bonner, Karen I; Orwin, Kate; Peltzer, Duane A

2014-01-01

Plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. These effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. We used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal legacy caused by invasion of the non-native tree Pinus contorta into a native plant community. Pinus facilitated ectomycorrhizal infection of the co-occurring invasive tree, Pseudotsuga menziesii, but not conspecific Pinus (which always had ectomycorrhizas) nor the native pioneer Kunzea ericoides (which never had ectomycorrhizas). Pinus also caused a major shift in soil nutrient cycling as indicated by increased bacterial dominance, NO3-N (17-fold increase) and available phosphorus (3.2-fold increase) in soils, which in turn promoted increased growth of graminoids. These results parallel field observations, where Pinus removal is associated with invasion by non-native grasses and herbs, and suggest that legacies of Pinus on soil nutrient cycling thus indirectly promote invasion of other non-native plant species. Our findings demonstrate that multi-trophic belowground legacies are an important but hitherto largely unconsidered factor in plant community reassembly following invasive plant removal. Published by Oxford University Press on behalf of the Annals of Botany Company.

Belowground legacies of Pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown

PubMed Central

Dickie, Ian A.; St John, Mark G.; Yeates, Gregor W.; Morse, Chris W.; Bonner, Karen I.; Orwin, Kate; Peltzer, Duane A.

2013-01-01

Plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. These effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. We used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal legacy caused by invasion of the non-native tree Pinus contorta into a native plant community. Pinus facilitated ectomycorrhizal infection of the co-occurring invasive tree, Pseudotsuga menziesii, but not conspecific Pinus (which always had ectomycorrhizas) nor the native pioneer Kunzea ericoides (which never had ectomycorrhizas). Pinus also caused a major shift in soil nutrient cycling as indicated by increased bacterial dominance, NO3-N (17-fold increase) and available phosphorus (3.2-fold increase) in soils, which in turn promoted increased growth of graminoids. These results parallel field observations, where Pinus removal is associated with invasion by non-native grasses and herbs, and suggest that legacies of Pinus on soil nutrient cycling thus indirectly promote invasion of other non-native plant species. Our findings demonstrate that multi-trophic belowground legacies are an important but hitherto largely unconsidered factor in plant community reassembly following invasive plant removal. PMID:25228312

Factors affecting the process performance of biofiltration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kopchynski, D.M.; Farmer, R.W.; Maier, W.J.

1996-11-01

Biofiltration is an emerging biological treatment technology for the removal of airborne VOCs from industrial process waste streams. Removal of air-phase VOCs by biofiltration is accomplished by contacting a process airstream with an active microbial biofilm attached to a solid phase packing. VOCs that partition into the biofilm are aerobically oxidized to the endproducts of water, carbon dioxide and salts. A multiple reactor biofiltration pilot plant test program has been in progress at the University of Minnesota Environmental Engineering Laboratories since 1992. The primary goal of the program is to study factors that affect biofiltration process performance. Initial results ofmore » this test program were reported in a previous conference paper and master`s thesis. This paper presents the results of more recent studies that focus on the effects of: (1) biofilm accumulation (which in turn causes a decrease in biofilter bed porosity and packing bed surface area), (2) rates of nutrient addition, and (3) chemical properties of the target contaminant, on biofiltration removal performance. Removal performance was evaluated by determining biofilter removal capacities and efficiencies for various substrate feeds. The performance parameters were measured under constant contaminant inlet concentrations and under constant temperature. Three VOCs were selected for study and they are: MEK, (methyl ethyl ketone), xylene, and hexane. MEK, xylene, and hexane were chosen because they are representative of widely used industrial solvents and they have significantly different Henry`s law constants relative to each other (the MEK value < Xylene value < Hexane value). Henry`s law constants quantify the partitioning of a chemical between the air and water-biofilm phase and therefore can be used to correlate the effect of chemical properties on biofilter removal capacities. This paper also introduces a new model for the biofiltration process.« less

Comparison of different packing materials for the biofiltration of air toxics.

PubMed

Sakuma, Takeyuki; Hattori, Toshihiro; Deshusses, Marc A

2006-11-01

Four different biofilter packing materials (two porous ceramics, perlite, and open pore polyurethane foam) were compared for the removal of toluene vapors. The focus was on evaluating performance at relatively short gas retention time (13.5 and 27 sec). The reactors were initially operated as biotrickling filters with continuous feeding and trickling of a nutrient solution. After significant plugging of the biotrickling filter beds with biomass was observed, the operation mode was switched to biofiltration with only periodic supply of mineral nutrients. This resulted in stable conditions, which allowed detailed investigations over > 6 months. The reactor packed with cattle bone Porcelite (CBP), a ceramic material containing some macronutrients and micronutrients, exhibited the highest performance. The critical load (i.e., load at which 95% removal occurred) was 29 g m(-3) hr(-1) at a gas retention time of 13.5 sec and 66 g m(-3) hr(-1) at a gas retention time of 27 sec. After the long-term experiment, the packing materials were taken from the reactors and examined. The reactors were divided into three sections, top, middle, and bottom, to determine whether spatial differentiation of biomass occurred. The assays included a double-staining technique to count total and live microorganisms and determination of moisture, protein, and dry weight contents. Microbial community analysis was also conducted by denaturing gradient gel electrophoresis. The results showed that most reactors had a significant fraction of inactive biomass. Comparatively, the CBP biofilter held significantly higher densities of active biomass, which may be the reason for the higher toluene removal performance. The analyses suggest that favorable material properties and the nutrients slowly released by the CBP provided better environmental conditions for the process culture.

A practitioner's perspective on the application and research needs of membrane bioreactors for municipal wastewater treatment.

PubMed

Kraemer, Jeremy T; Menniti, Adrienne L; Erdal, Zeynep K; Constantine, Timothy A; Johnson, Bruce R; Daigger, Glen T; Crawford, George V

2012-10-01

The application of membrane bioreactors (MBRs) for municipal wastewater treatment has increased dramatically over the last decade. From a practitioner's perspective, design practice has evolved over five "generations" in the areas of biological process optimization, separating process design from equipment supply, and reliability/redundancy thereby facilitating "large" MBRs (e.g. 150,000 m(3)/day). MBR advantages and disadvantages, and process design to accommodate biological nutrient removal, high mixed liquor suspended solids concentrations, operation and maintenance, peak flows, and procurement are reviewed from the design practitioner's perspective. Finally, four knowledge areas are identified as important to practitioners meriting further research and development: (i) membrane design and performance such as improving peak flow characteristics and decreasing operating costs; (ii) process design and performance such as managing the fluid properties of the biological solids, disinfection, and microcontaminant removal; (iii) facility design such as equipment standardization and decreasing mechanical complexity; and (iv) sustainability such as anaerobic MBRs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Growing duckweed in swine wastewater for nutrient recovery and biomass production.

PubMed

Xu, Jiele; Shen, Genxiang

2011-01-01

Spirodela oligorrhiza, a promising duckweed identified in previous studies, was examined under different cropping conditions for nutrient recovery from swine wastewater and biomass production. To prevent algae bloom during the start-up of a duckweed system, inoculating 60% of the water surface with duckweed fronds was required. In the growing season, the duckweed system was capable of removing 83.7% and 89.4% of total nitrogen (TN) and total phosphorus (TP) respectively from 6% swine lagoon water in eight weeks at a harvest frequency of twice a week. The total biomass harvested was 5.30 times that of the starting amount. In winter, nutrients could still be substantially removed in spite of the limited duckweed growth, which was probably attributed to the improved protein accumulation of duckweed plants and the nutrient uptake by the attached biofilm (algae and bacteria) on duckweed and walls of the system. Copyright © 2010 Elsevier Ltd. All rights reserved.

Model-based evaluation of struvite recovery from an in-line stripper in a BNR process (BCFS).

PubMed

Hao, X D; van Loosdrecht, M C M

2006-01-01

Phosphate removal and recovery can be combined in BNR processes. This may be realised by struvite precipitation from the supernatant of the sludge in anaerobic compartments. This can be beneficial for either improving bio-P removal effluent quality or lowering the influent COD/P ratio required for bio-P removal. For this reason, a patented BNR process, BCFS, was developed and applied in The Netherlands. Several questions relating to P-recovery and behaviour of the system remain unclear and need to be ascertained. For this purpose, a modelling technique was employed in this study. With the help of a previous developed model describing carbon oxidation and nutrient removal, three cases were fully simulated. The simulations demonstrated that there was an optimal stripping flow rate and P-recovery would increase in costs and bio-P activity might be negatively affected due to decreased bio-P efficiency if this value was exceeded. The simulations indicated that the minimal COD(biod)/P ratio required for the effluent standard (1 g P/m3) could be lowered from 20 to 10 with 36% of P-recovery. A simulation with dynamic inflow revealed that the dynamic influent loads affected slightly the anaerobic supernatant phosphate concentration but the effluent phosphate concentration would not be affected with regular P-recovery.

Food and symptom generation in functional gastrointestinal disorders: physiological aspects.

PubMed

Farré, Ricard; Tack, Jan

2013-05-01

The response of the gastrointestinal tract (GIT) to ingestion of food is a complex and closely controlled process, which allows optimization of propulsion, digestion, absorption of nutrients, and removal of indigestible remnants. This review summarizes current knowledge on the mechanisms that control the response of the GIT to food intake. During the cephalic phase, triggered by cortical food-related influences, the GIT prepares for receiving nutrients. The gastric phase is dominated by the mechanical effect of the meal volume. Accumulation of food in the stomach activates tension-sensitive mechanoreceptors, which in turn stimulate gastric accommodation and gastric acid secretion through the intrinsic and vago-vagal reflex pathways. After meal ingestion, the tightly controlled process of gastric emptying starts, with arrival of nutrients in the duodenum triggering negative feedback on emptying and stimulating secretion of digestive enzymes through the neural (mainly vago-vagal reflex, but also intrinsic) and endocrine (release of peptides from entero-endocrine cells) pathways. Several types of specialized receptors detect the presence of all main categories of nutrients. In addition, the gastrointestinal mucosa expresses receptors of the T1R and T2R families (taste receptors) and several members of the transient receptor potential channel family, all of which are putatively involved in the detection of specific tastants in the lumen. Activation of nutrient and taste sensors also activates the extrinsic and intrinsic neural, as well as entero-endocrine, pathways. During passage through the small bowel, nutrients are progressively extracted, and electrolyte-rich liquid intestinal content with non-digestible residue is delivered to the colon. The colon provides absorption of the water and electrolytes, storage of non-digestible remnants of food, aboral propulsion of contents, and finally evacuation through defecation.

CO2 , NOx and SOx removal from flue gas via microalgae cultivation: a critical review.

PubMed

Yen, Hong-Wei; Ho, Shih-Hsin; Chen, Chun-Yen; Chang, Jo-Shu

2015-06-01

Flue gas refers to the gas emitting from the combustion processes, and it contains CO2 , NOx , SOx and other potentially hazardous compounds. Due to the increasing concerns of CO2 emissions and environmental pollution, the cleaning process of flue gas has attracted much attention. Using microalgae to clean up flue gas via photosynthesis is considered a promising CO2 mitigation process for flue gas. However, the impurities in the flue gas may inhibit microalgal growth, leading to a lower microalgae-based CO2 fixation rate. The inhibition effects of SOx that contribute to the low pH could be alleviated by maintaining a stable pH level, while NOx can be utilized as a nitrogen source to promote microalgae growth when it dissolves and is oxidized in the culture medium. The yielded microalgal biomass from fixing flue gas CO2 and utilizing NOx and SOx as nutrients would become suitable feedstock to produce biofuels and bio-based chemicals. In addition to the removal of SOx , NOx and CO2 , using microalgae to remove heavy metals from flue gas is also quite attractive. In conclusion, the use of microalgae for simultaneous removal of CO2 , SOx and NOx from flue gas is an environmentally benign process and represents an ideal platform for CO2 reutilization. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bioelectro-Claus processes using MFC technology: Influence of co-substrate.

PubMed

Raschitor, A; Soreanu, G; Fernandez-Marchante, C M; Lobato, J; Cañizares, P; Cretescu, I; Rodrigo, M A

2015-01-01

This work is focused on the removal of sulphide from wastewater using a two chamber microbial fuel cell, seeded with activated sludge and operated in semi-continuous mode. Two co-substrates were used in order to provide the system for carbon and nutrient source: actual urban wastewater and synthetic wastewater. Results show that sulphide is efficiency depleted (removals over 94%) and that electricity is efficiently produced (maximum power density is 150 mW m(-2)) meanwhile COD is also oxidised (removals higher than 60%). Sulphur and sulphate are obtained as the final products of the oxidation and final speciation depends on the type of co-substrate used. The start-up of the system is very rapid and production of electricity and polarisation curves do not depend on the co-substrate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Early-stage changes in natural (13)C and (15)N abundance and nutrient dynamics during different litter decomposition.

PubMed

Gautam, Mukesh Kumar; Lee, Kwang-Sik; Song, Byeong-Yeol; Lee, Dongho; Bong, Yeon-Sik

2016-05-01

Decomposition, nutrient, and isotopic (δ(13)C and δ(15)N) dynamics during 1 year were studied for leaf and twig litters of Pinus densiflora, Castanea crenata, Erigeron annuus, and Miscanthus sinensis growing on a highly weathered soil with constrained nutrient supply using litterbags in a cool temperate region of South Korea. Decay constant (k/year) ranged from 0.58 to 1.29/year, and mass loss ranged from 22.36 to 58.43 % among litter types. The results demonstrate that mass loss and nutrient dynamics of decomposing litter were influenced by the seasonality of mineralization and immobilization processes. In general, most nutrients exhibited alternate phases of rapid mineralization followed by gradual immobilization, except K, which was released throughout the field incubation. At the end of study, among all the nutrients only N and P showed net immobilization. Mobility of different nutrients from decomposing litter as the percentage of initial litter nutrient concentration was in the order of K > Mg > Ca > N ≈ P. The δ(13)C (0.32-6.70 ‰) and δ(15)N (0.74-3.90 ‰) values of residual litters showed nonlinear increase and decrease, respectively compared to initial isotopic values during decomposition. Litter of different functional types and chemical quality converged toward a conservative nutrient use strategy through mechanisms of slow decomposition and slow nutrient mobilization. Our results indicate that litter quality and season, are the most important regulators of litter decomposition in these forests. The results revealed significant relationships between litter decomposition rates and N, C:N ratio and P, and seasonality (temperature). These results and the convergence of different litters towards conservative nutrient use in these nutrient constrained ecosystems imply optimization of litter management because litter removal can have cascading effects on litter decomposition and nutrient availability in these systems.

Nutrients: a major consideration in intensive forest management

Treesearch

James W. Hornbeck

1977-01-01

Estimates of nutrient losses are compared for stem-only harvest versus a whole-tree harvest of a clearcut northern hardwood stand. Combined nutrient losses due to increased leaching and removal of vegetation after stem-only harvesting are estimated to be 334 kg/ha for calcium and 265 kg/ha for nitrogen. For a whole-tree harvest, combined losses are estimated at 537 kg/...

Nutrient availability in rangeland soils: influence of prescribed burning, herbaceous vegetation removal, overseeding with Bromus tectorum, season, and elevation

Treesearch

R. R. Blank; J. Chambers; B. Roundy; A. Whittaker

2007-01-01

Soil nutrient availability influences plant invasions. Resin capsules were used to examine soil nutrient bioavailability along 2 sagebrush-grassland elevation transects in the east Tintic Range (Utah) and Shoshone Range (Nevada). In the fall of 2001, treatments were applied to 3 replicate plots at each site, which included prescribed burning, herbaceous vegetation...

Biofiltration: Fundamentals, design and operations principles and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swanson, W.J.; Loehr, R.C.

1997-06-01

Biofiltration is a biological air pollution control technology for volatile organic compounds (VOCs). This paper summarizes the fundamentals, design and operation, and application of the process. Biofiltration has been demonstrated to be an effective technology for VOCs from many industries. Large and full-scale systems are in use in Europe and the US. With proper design and operation, VOC removal efficiencies of 95--99% have been achieved. Important parameters for design and performance are empty-bed contact time, gas surface loading, mass loading, elimination capacity, and removal efficiency. Key design and operation factors include chemical and media properties, moisture, pH, temperature, nutrient availability,more » gas pretreatment, and variations in loading.« less

Sewage-treatment under substantial load variations in winter tourism areas--a full case study.

PubMed

Winkler, S; Matsché, N; Gamperer, T; Dum, M

2004-01-01

The sewage-load variations in winter tourism areas are characterized by sudden increases--in the range of a factor two to three--within only a few days at the start and the end of the tourist season, especially at Christmas. The sudden load increases occur during periods of low wastewater temperatures, which is an additional demanding factor with respect to nitrogen removal. A full case study was carried out at WWTP Saalfelden, which is located near one of Austria's largest skiing resorts. The plant is designed for 80,000 PE and built according to the HYBRID-concept, which is a special two stage activated sludge process for extensive nutrient removal.

Seasonal variation exceeds effects of salmon carcass additions on benthic food webs in the Elwha River

USGS Publications Warehouse

Morley, S.A.; Coe, H.J.; Duda, J.J.; Dunphy, L.S.; McHenry, M.L.; Beckman, B.R.; Elofson, M.; Sampson, E. M.; Ward, L.

2016-01-01

Dam removal and other fish barrier removal projects in western North America are assumed to boost freshwater productivity via the transport of marine-derived nutrients from recolonizing Pacific salmon (Oncorhynchus spp.). In anticipation of the removal of two hydroelectric dams on the Elwha River in Washington State, we tested this hypothesis with a salmon carcass addition experiment. Our study was designed to examine how background nutrient dynamics and benthic food webs vary seasonally, and how these features respond to salmon subsidies. We conducted our experiment in six side channels of the Elwha River, each with a spatially paired reference and treatment reach. Each reach was sampled on multiple occasions from October 2007 to August 2008, before and after carcass placement. We evaluated nutrient limitation status; measured water chemistry, periphyton, benthic invertebrates, and juvenile rainbow trout (O. mykiss) response; and traced salmon-derived nutrient uptake using stable isotopes. Outside of winter, algal accrual was limited by both nitrogen and phosphorous and remained so even in the presence of salmon carcasses. One month after salmon addition, dissolved inorganic nitrogen levels doubled in treatment reaches. Two months after addition, benthic algal accrual was significantly elevated. We detected no changes in invertebrate or fish metrics, with the exception of 15N enrichment. Natural seasonal variability was greater than salmon effects for the majority of our response metrics. Yet seasonality and synchronicity of nutrient supply and demand are often overlooked in nutrient enhancement studies. Timing and magnitude of salmon-derived nitrogen utilization suggest that uptake of dissolved nutrients was favored over direct consumption of carcasses. The highest proportion of salmon-derived nitrogen was incorporated by herbivores (18–30%) and peaked 1–2 months after carcass addition. Peak nitrogen enrichment in predators (11–16%) occurred 2–3 months after addition. All taxa returned to background δ15N levels by 7 months. Since this study was conducted, both dams on the Elwha River were removed over 2011–2014 to open over 90% of the basin to anadromous fishes. We anticipate that as the full portfolio of salmon species expands through the basin, nutrient supply and demand will come into better balance.

Modeling High Rate Phosphorus and Nitrogen Removal in a Vertical Flow Alum Sludge based Constructed Wetlands

NASA Astrophysics Data System (ADS)

Jeyakumar, Lordwin; Zhao, Yaqian

2014-05-01

Increased awareness of the impacts of diffuse pollution and their intensification has pushed forward the need for the development of low-cost wastewater treatment techniques. One of such efforts is the use of novel DASC (Dewatered Alum Sludge Cakes) based constructed wetlands (CWs) for removing nutrients, organics, trace elements and other pollutants from wastewater. Understanding of the processes in CWs requires a numerical model that describes the biochemical transformation and degradation processes in subsurface vertical flow (VF) CWs. Therefore, this research focuses on the development of a process-based model for phosphorus (P) and nitrogen (N) removal to achieve a stable performance by using DASC as a substrate in CWs treatment system. An object-oriented modelling tool known as "STELLA" which works based on the principle of system dynamics is used for the development of P and N model. The core objective of the modelling work is oriented towards understanding the process in DASC-based CWs and optimizes design criteria. The P and N dynamic model is developed for DASC-based CWs. The P model developed exclusively for DASC-based CW was able to simulate the effluent P concentration leaving the system satisfactorily. Moreover, the developed P dynamic model has identified the major P pathways as adsorption (72%) followed by plant uptake (20%) and microbial uptake (7%) in single-stage laboratory scale DASC-based CW. Similarly, P dynamic simulation model was developed to simulate the four-stage laboratory scale DASC-based CWs. It was found that simulated and observed values of P removal were in good agreement. The fate of P in all the four stages clearly shows that adsorption played a pivotal role in each stage of the system due to the use of the DASC as a substrate. P adsorption by wetland substrate/DASC represents 59-75% of total P reduction. Subsequently, plant uptake and microbial uptake have lesser role regarding P removal (as compared to adsorption).With regard to N, DASC-based CWs dynamic model was developed and was run for 18 months from Feb 2009 to May 2010. The results reveal that the simulated effluent DN, NH4-N, NO3-N and TN had a considerably good agreement with the observed results. The TN removal was found to be 52% in the DASC-based CW. Interestingly, NIT is the main agent (65.60%) for the removal followed by ad (11.90%), AMM (8.90%), NH4-N (P) (5.90%), and NO3-N (P) (4.40%). DeN did not result in any significant removal (2.90%) in DASC-based CW which may be due to lack of anaerobic condition and absence of carbon sources. The N model also attempted to simulate the internal process behaviour of the system which provided a useful tool for gaining insight into the N dynamics of VFCWs. The results obtained for both N and P models can be used to improve the design of the newly developed DASC-based CWs to increase the efficiency of nutrient removal by CWs.

Impacts of sewage effluent on tree survival, water quality and nutrient removal in coastal plain swamps

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuenzler, E.J.

1987-09-01

An investigation was conducted of the impacts of sprayed municipal sewage on swamp tree survival and the effects of the swamp system on nutrient concentrations below the outfalls on two streams on the coastal plain of North Carolina. Effluent was discharged to one swamp stream by aerial spraying and to the other stream by way of a small ditch. Ninety-eight percent of the trees struck directly by the spray were dead within 18 months of the date spraying began. Both swamp systems removed sufficient quantities of nitrogen and phosphorus within a few kilometers to account for virtually all of themore » sewage nutrient load to the swamps.« less

Towards a consensus-based biokinetic model for green microalgae - The ASM-A.

PubMed

Wágner, Dorottya S; Valverde-Pérez, Borja; Sæbø, Mariann; Bregua de la Sotilla, Marta; Van Wagenen, Jonathan; Smets, Barth F; Plósz, Benedek Gy

2016-10-15

Cultivation of microalgae in open ponds and closed photobioreactors (PBRs) using wastewater resources offers an opportunity for biochemical nutrient recovery. Effective reactor system design and process control of PBRs requires process models. Several models with different complexities have been developed to predict microalgal growth. However, none of these models can effectively describe all the relevant processes when microalgal growth is coupled with nutrient removal and recovery from wastewaters. Here, we present a mathematical model developed to simulate green microalgal growth (ASM-A) using the systematic approach of the activated sludge modelling (ASM) framework. The process model - identified based on a literature review and using new experimental data - accounts for factors influencing photoautotrophic and heterotrophic microalgal growth, nutrient uptake and storage (i.e. Droop model) and decay of microalgae. Model parameters were estimated using laboratory-scale batch and sequenced batch experiments using the novel Latin Hypercube Sampling based Simplex (LHSS) method. The model was evaluated using independent data obtained in a 24-L PBR operated in sequenced batch mode. Identifiability of the model was assessed. The model can effectively describe microalgal biomass growth, ammonia and phosphate concentrations as well as the phosphorus storage using a set of average parameter values estimated with the experimental data. A statistical analysis of simulation and measured data suggests that culture history and substrate availability can introduce significant variability on parameter values for predicting the reaction rates for bulk nitrate and the intracellularly stored nitrogen state-variables, thereby requiring scenario specific model calibration. ASM-A was identified using standard cultivation medium and it can provide a platform for extensions accounting for factors influencing algal growth and nutrient storage using wastewater resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Algal biofuels from urban wastewaters: maximizing biomass yield using nutrients recycled from hydrothermal processing of biomass.

PubMed

Selvaratnam, T; Pegallapati, A K; Reddy, H; Kanapathipillai, N; Nirmalakhandan, N; Deng, S; Lammers, P J

2015-04-01

Recent studies have proposed algal cultivation in urban wastewaters for the dual purpose of waste treatment and bioenergy production from the resulting biomass. This study proposes an enhancement to this approach that integrates cultivation of an acidophilic strain, Galdieria sulphuraria 5587.1, in a closed photobioreactor (PBR); hydrothermal liquefaction (HTL) of the wet algal biomass; and recirculation of the nutrient-rich aqueous product (AP) of HTL to the PBR to achieve higher biomass productivity than that could be achieved with raw wastewater. The premise is that recycling nutrients in the AP can maintain optimal C, N and P levels in the PBR to maximize biomass growth to increase energy returns. Growth studies on the test species validated growth on AP derived from HTL at temperatures from 180 to 300°C. Doubling N and P concentrations over normal levels in wastewater resulted in biomass productivity gains of 20-25% while N and P removal rates also doubled. Copyright © 2015 Elsevier Ltd. All rights reserved.

Response to L. Land comment on Bricker, Rice, Bricker (2014) From Headwaters to Coast: Influence of human activities on water quality of the Potomac River Estuary. Aquatic Geochemistry 20: 291-324

USGS Publications Warehouse

Bricker, Suzanne B.; Rice, Karen C.; Bricker, III

2014-01-01

Overabundance of nutrients is considered one of the top challenges to most populated coastal water bodies, including Chesapeake Bay (Executive Order 13508). As scientists, one of our responsibilities is to contribute to the discussion and evaluation of management actions that have the potential to decrease pollution with concomitant improvement of water quality. Results of our science should inform the legislative process for public policy. Bricker et al. (2014) consider the use of shellfish (i.e., oysters) to remediate nutrient pollution in the Potomac River Estuary (PRE), a tributary to Chesapeake Bay. This concept, termed bioextraction, has generated interest around the globe and has shown promise as a nutrient-removal method in other estuaries and with other shellfish species (Lindahl et al. 2005; Ferreira et al. 2009; Shumway 2011; Silva et al. 2011; Carmichael et al. 2012; Pollack et al. 2013; Rose et al. 2014).

A review on experimental design for pollutants removal in water treatment with the aid of artificial intelligence.

PubMed

Fan, Mingyi; Hu, Jiwei; Cao, Rensheng; Ruan, Wenqian; Wei, Xionghui

2018-06-01

Water pollution occurs mainly due to inorganic and organic pollutants, such as nutrients, heavy metals and persistent organic pollutants. For the modeling and optimization of pollutants removal, artificial intelligence (AI) has been used as a major tool in the experimental design that can generate the optimal operational variables, since AI has recently gained a tremendous advance. The present review describes the fundamentals, advantages and limitations of AI tools. Artificial neural networks (ANNs) are the AI tools frequently adopted to predict the pollutants removal processes because of their capabilities of self-learning and self-adapting, while genetic algorithm (GA) and particle swarm optimization (PSO) are also useful AI methodologies in efficient search for the global optima. This article summarizes the modeling and optimization of pollutants removal processes in water treatment by using multilayer perception, fuzzy neural, radial basis function and self-organizing map networks. Furthermore, the results conclude that the hybrid models of ANNs with GA and PSO can be successfully applied in water treatment with satisfactory accuracies. Finally, the limitations of current AI tools and their new developments are also highlighted for prospective applications in the environmental protection. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhancement of nutrient removal from swine wastewater digestate coupled to biogas purification by microalgae Scenedesmus spp.

PubMed

Prandini, Jean Michel; da Silva, Márcio Luís Busi; Mezzari, Melissa Paola; Pirolli, Mateus; Michelon, William; Soares, Hugo Moreira

2016-02-01

This work investigated the effects of swine wastewater-derived biogas on microalgae biomass production and nutrient removal rates from piggery wastewater concomitantly with biogas filtration. Photobioreactors with dominant Scenedesmus spp. were prepared using non-sterile digestate and exposed to different photoperiods. In the presence of biogas and autotrophic conditions microalgae yield of 1.1±0.2 g L(-1) (growth rate of 141.8±3.5 mg L(-1) d(-1)) was obtained leading to faster N-NH3 and P-PO4(3-) assimilation rate of 21.2±1.2 and 3.5±2.5 mg L(-1) d(-1), respectively. H2S up to 3000 ppmv was not inhibitory and completely removed. Maximum CO2 assimilation of 219±4.8 mg L(-1) d(-1) was achieved. Biological consumption of CH4 up to 18% v/v was verified. O2 up to 22% v/v was controlled by adding acetate to exacerbate oxygen demand by microorganisms. Microalgae-based wastewater treatment coupled to biogas purification accelerates nutrient removal concomitantly producing valuable biomass and biomethane. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioremediation of reject water from anaerobically digested waste water sludge with macroalgae (Ulva lactuca, Chlorophyta).

PubMed

Sode, Sidsel; Bruhn, Annette; Balsby, Thorsten J S; Larsen, Martin Mørk; Gotfredsen, Annemarie; Rasmussen, Michael Bo

2013-10-01

Phosphorus and biologically active nitrogen are valuable nutrient resources. Bioremediation with macroalgae is a potential means for recovering nutrients from waste streams. In this study, reject water from anaerobically digested sewage sludge was successfully tested as nutrient source for cultivation of the green macroalgae Ulva lactuca. Maximal growth rates of 54.57±2.16% FW d(-1) were achieved at reject water concentrations equivalent to 50 μM NH4(+). Based on the results, the growth and nutrient removal was parameterised as function of NH4(+) concentration a tool for optimisation of any similar phycoremediation system. Maximal nutrient removal rates of 22.7 mg N g DW(-1) d(-1) and 2.7 mg P g DW(-1) d(-1) were achieved at reject water concentrations equivalent to 80 and 89 μM NH4(+), respectively. A combined and integrated use of the produced biomass in a biorefinery is thought to improve the feasibility of using Ulva for bioremediation of reject water. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

Wetland management reduces sediment and nutrient loading to the upper Mississippi River

USGS Publications Warehouse

Kreiling, Rebecca M.; Schubauer-Berigan, Joseph P.; Richardson, William B.; Bartsch, Lynn; Hughes, Peter E.; Strauss, Eric A.

2013-01-01

Restored riparian wetlands in the Upper Mississippi River basin have potential to remove sediment and nutrients from tributaries before they flow into the Mississippi River. For 3 yr we calculated retention efficiencies of a marsh complex, which consisted of a restored marsh and an adjacent natural marsh that were connected to Halfway Creek, a small tributary of the Mississippi. We measured sediment, N, and P removal through a mass balance budget approach, N removal through denitrification, and N and P removal through mechanical soil excavation. The marsh complex had average retention rates of approximately 30 Mg sediment ha−1 yr−1, 26 kg total N ha−1 yr−1, and 20 kg total P ha−1 yr−1. Water flowed into the restored marsh only during high-discharge events. Although the majority of retention occurred in the natural marsh, portions of the natural marsh were hydrologically disconnected at low discharge due to historical over-bank sedimentation. The natural marsh removed >60% of sediment, >10% of P, and >5% of N loads (except the first year, when it was a N source). The marsh complex was a source of NH4+ and soluble reactive P. The average denitrification rate for the marsh complex was 2.88 mg N m−2 h−1. Soil excavation removed 3600 Mg of sediment, 5.6 Mg of N, and 2.7 Mg of P from the restored marsh. The marsh complex was effective in removing sediment and nutrients from storm flows; however, retention could be increased if more water was diverted into both restored and natural marshes before entering the river.

Micronutrients in Parenteral Nutrition: Boron, Silicon, and Fluoride

USDA-ARS?s Scientific Manuscript database

Long-term parenteral nutrition (providing nutrients intravenously) is a life-saving treatment for patients with severe malabsorption of nutrients caused by intestinal failure, intestinal trauma (for example, gunshot or stab wounds), and intestinal removal. Metabolic bone disease characterized by min...

Pilot investigation of two-stage biofiltration for removal of natural organic matter in drinking water treatment.

PubMed

Fu, Jie; Lee, Wan-Ning; Coleman, Clark; Meyer, Melissa; Carter, Jason; Nowack, Kirk; Huang, Ching-Hua

2017-01-01

A pilot study employing two parallel trains of two-stage biofiltration, i.e., a sand/anthracite (SA) biofilter followed by a biologically-active granular activated carbon (GAC) contactor, was conducted to test the efficiency, feasibility and stability of biofiltration for removing natural organic matter (NOM) after coagulation in a drinking water treatment plant. Results showed the biofiltration process could effectively remove turbidity (<0.1 NTU in all effluents) and NOM (>24% of dissolved organic carbon (DOC), >57% of UV 254 , and >44% of SUVA 254 ), where the SA biofilters showed a strong capacity for turbidity removal, while the GAC contactors played the dominant role in NOM removal. The vertical profile of water quality in the GAC contactors indicated the middle-upper portion was the critical zone for the removal of NOM, where relatively higher adsorption and enhanced biological removal were afforded. Fluorescence excitation-emission matrix (EEM) analysis of NOM showed that the GAC contactors effectively decreased the content of humic-like component, while protein-like component was refractory for the biofiltration process. Nutrients (NH 4 -N and PO 4 -P) supplementation applied upstream of one of the two-stage biofiltration trains (called engineered biofiltration) stimulated the growth of microorganisms, and showed a modest effect on promoting the biological removal of small non-aromatic compositions in NOM. Redundancy analysis (RDA) indicated influent UV 254 was the most explanatory water quality parameter for GAC contactors' treatment performance, and a high load of UV 254 would result in significantly reduced removals of UV 254 and SUVA 254 . Copyright © 2016 Elsevier Ltd. All rights reserved.

Nitrogen removal by recycle water nitritation as an attractive alternative for retrofit technologies in municipal wastewater treatment plants.

PubMed

Gil, K I; Choi, E

2004-01-01

The recycle water from sludge processing in municipal wastewater treatment plants causes many serious problems in the efficiency and stability of the mainstream process. Thus, the design approach for recycle water is an important part of any biological nutrient removal system design when a retrofit technology is required for upgrading an existing plant. Moreover, the application of nitrogen removal from recycle water using the nitritation process has recently increased due to economic reasons associated with an effective carbon allocation as well as the minimization of aeration costs. However, for the actual application of recycle water nitritation, it has not been fully examined whether or not additional volume would be required in an existing plant. In this paper, the addition of recycle water nitritation to an existing plant was evaluated based on a volume analysis and estimation of final effluent quality. It was expected that using the reserve volume of the aeration tank in existing plants, recycle water nitritation could be applied to a plant without any enlargement. With the addition of recycle water nitritation, it was estimated that the final effluent quality would be improved and stabilized, especially in the winter season.

Space Bioreactor Science Workshop

NASA Technical Reports Server (NTRS)

Morrison, Dennis R. (Editor)

1987-01-01

The first space bioreactor has been designed for microprocessor control, no gaseous headspace, circulation and resupply of culture medium, and a slow mixing in very low shear regimes. Various ground based bioreactors are being used to test reactor vessel design, on-line sensors, effects of shear, nutrient supply, and waste removal from continuous culture of human cells attached to microcarriers. The small (500 ml) bioreactor is being constructed for flight experiments in the Shuttle middeck to verify systems operation under microgravity conditions and to measure the efficiencies of mass transport, gas transfer, oxygen consumption, and control of low shear stress on cells. Applications of microcarrier cultures, development of the first space bioreactor flight system, shear and mixing effects on cells, process control, and methods to monitor cell metabolism and nutrient requirements are among the topics covered.

Removing organic and nitrogen content from a highly saline municipal wastewater reverse osmosis concentrate by UV/H2O2-BAC treatment.

PubMed

Pradhan, Shovana; Fan, Linhua; Roddick, Felicity A

2015-10-01

Reverse osmosis (RO) concentrate (ROC) streams generated from RO-based municipal wastewater reclamation processes pose potential health and environmental risks on their disposal to confined water bodies such as bays. A UV/H2O2 advanced oxidation process followed by a biological activated carbon (BAC) treatment was evaluated at lab-scale for the removal of organic and nutrient content from a highly saline ROC (TDS 16 g L(-1), EC 23.5 mS cm(-1)) for its safe disposal to the receiving environment. Over the 230-day operation of the UV/H2O2-BAC process, the colour and UV absorbance (254 nm) of the ROC were reduced to well below those of the influent to the reclamation process. The concentrations of DOC and total nitrogen (TN) were reduced by approximately 60% at an empty bed contact time (EBCT) of 60 min. The reduction in ammonia nitrogen by the BAC remained high under all conditions tested (>90%). Further investigation confirmed that the presence of residual peroxide in the UV/H2O2 treated ROC was beneficial for DOC removal, but markedly inhibited the activities of the nitrifying bacteria (i.e., nitrite oxidising bacteria) in the BAC system and hence compromised total nitrogen removal. This work demonstrated that the BAC treatment could be acclimated to the very high salinity environment, and could be used as a robust method for the removal of organic matter and nitrogen from the pre-oxidised ROC under optimised conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Functional profile of black spruce wetlands in Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Post, R.A.

1996-09-01

The profile describes the ecologic context and wetland functions of black spruce (Picea mariana) wetlands (BSWs) covering about 14 million ha of Alaska taiga. Ecologic descriptions include climate, permafrost, landforms, post-Pleistocene vegetation, fire, successional processes, black spruce community types and adaptations, and characteristics of BSWs. The profile describes human activities potentially affecting BSWs and identifies research literature and data gaps generally applicable to BSWs. Hydrologic, water quality, global biogeochemical, and ecologic functions of BSWs, as well as their socioeconomic uses, appear in the profile, along with potential functional indicators, expected sensitivities of functions to fill placement or weltand drainage, andmore » potential mitigation strategies for impacts. Functional analysis separately considers ombrotrophic and minerotrophic BSWs where appropriate. Depending on trophic status, Alaska`s BSWs perform several low-magnitude hydrologic (groundwater discharge and recharge, flow regulation, and erosion control) and ecologic (nutrient export, nutrient cycling, and food-chain support) functions and several substantial water quality (sediment retention, nutrient transformation, nutrient uptake, and contaminant removal), global biogeochemical (carbon cycling and storage), and ecologic (avian and mammalian habitat) functions. BSWs also provide important socioeconomic uses: harvested of wetland-dependent fish, wildlife, and plant resources and active winter recreation.« less

Nutrient capture and recycling by periphyton attached to modified agrowaste carriers.

PubMed

Wan, Juanjuan; Liu, Xuemei; Wu, Chenxi; Wu, Yonghong

2016-04-01

The reuse of periphytic biofilm from traditional wastewater treatment (i.e., active sludge process) is inefficient to recycle nutrients due to low accumulation of nutrients. Then, in this study, peanut shell (PS), rice husk (RH), decomposed peanut shell (DPS), acidified rice husks (ARH), and a commonly used carrier-ceramsite (C, as the control)-were used to support the growth of periphyton. Results showed that DPS and ARH supported significantly higher periphyton biomass and metabolic versatility than PS and RH, respectively, due to the increased presence of positive groups. The total nitrogen (TN) and total phosphorus (TP) captured by periphyton were enhanced by 600-657 and 833-3255 % for DPS, and 461-1808 and 21-308 % for ARH, respectively. The removal of nutrients from simulated eutrophic surface waters using periphyton attached to DPS was improved by 24-47 % for TP, 12-048 % for TN, and 15-78 % for nitrate compared to the control. The results indicate that the periphyton attached to modified agrowaste was capable of efficiently entrapping and storing N and P from eutrophic water. This study also implies that the mixture of periphyton and the modified agrowaste carriers are promising raw materials of biofertilizer.

You are what you eat: O-linked N-acetylglucosamine in disease, development and epigenetics.

PubMed

Olivier-Van Stichelen, Stéphanie; Hanover, John A

2015-07-01

The O-linked N-acetylglucosamine (O-GlcNAc) modification is both responsive to nutrient availability and capable of altering intracellular cellular signalling. We summarize data defining a role for O-GlcNAcylation in metabolic homeostasis and epigenetic regulation of development in the intrauterine environment. O-GlcNAc transferase (OGT) catalyzes nutrient-driven O-GlcNAc addition and is subject to random X-inactivation. OGT plays key roles in growth factor signalling, stem cell biology, epigenetics and possibly imprinting. The O-GlcNAcase, which removes O-GlcNAc, is subject to tight regulation by higher order chromatin structure. O-GlcNAc cycling plays an important role in the intrauterine environment wherein OGT expression is an important biomarker of placental stress. Regulation of O-GlcNAc cycling by X-inactivation, epigenetic regulation and nutrient-driven processes makes it an ideal candidate for a nutrient-dependent epigenetic regulator of human disease. In addition, O-GlcNAc cycling influences chromatin modifiers critical to the regulation and timing of normal development including the polycomb repression complex and the ten-eleven translocation proteins mediating DNA methyl cytosine demethylation. The pathway also impacts the hypothalamic-pituitary-adrenal axis critical to intrauterine programming influencing disease susceptibility in later life.

Effect of treatment in a constructed wetland on toxicity of textile wastewater

USGS Publications Warehouse

Baughman, G.L.; Perkins, W.S.; Lasier, P.J.; Winger, P.V.

2003-01-01

Constructed wetlands for treating wastewater have proliferated in recent years and their characteristics have been studied extensively. In most cases, constructed wetlands have been used primarily for removal of nutrients and heavy metals. Extensive literature is available concerning construction and use of wetlands for treatment of wastewater. Even so, quantitative descriptions of wetland function and processes are highly empirical and difficult to extrapolate. The processes involved in removal of pollutants by wetlands are poorly understood, especially for waste streams as complex as textile effluents. The few studies conducted on treatment of textile wastewater in constructed wetlands were cited in earlier publications. Results of a two-year study of a full-scale wetland treating textile effluent are presented here. The paper describes the effects of the wetland on aquatic toxicity of the wastewater and draws conclusions about the utility and limitations of constructed wetlands for treatment of textile effluents.

Degradation of cyanotoxins (microcystin) in drinking water using photoelectrooxidation.

PubMed

Garcia, A C A; Rodrigues, M A S; Xavier, J L N; Gazulla, V; Meneguzzi, A; Bernardes, A M

2015-05-01

The discharge of sewage and industrial effluents containing high concentrations of pollutants in water bodies increases eutrophication. Cyanobacteria, some of the organisms whose growth is promoted by high nutrient concentrations, are resistant and produce several types of toxins, known as cyanotoxins, highly harmful to human beings. Current water treatment systems for the public water supply are not efficient in degradation of toxins. Advanced oxidation processes (AOP) have been tested for the removal of cyanotoxins, and the results have been positive. This study examines the application of photoelectrooxidation in the degradation of cyanotoxins (microcystins). The performance of the oxidative processes involved was evaluated separately: Photocatalysis, Electrolysis and Photoelectrooxidation. Results showed that the electrical current and UV radiation were directly associated with toxin degradation. The PEO system is efficient in removing cyanotoxins, and the reduction rate reached 99%. The final concentration of toxin was less than 1 µg/L of microcystin in the treated solution.

An evaluation of the sustainability of onsite wastewater treatment systems for nutrient management.

PubMed

Diaz-Elsayed, Nancy; Xu, Xiaofan; Balaguer-Barbosa, Maraida; Zhang, Qiong

2017-09-15

The impairment of water bodies from nutrient pollution is a challenging environmental problem that could lead to high eutrophic conditions, fish kills, and human illness, while negatively impacting industries that rely on thriving water bodies. Onsite wastewater treatment systems (OWTSs) are a major source of nutrients, however no prior studies have conducted a holistic sustainability assessment of OWTSs that considers their ability to manage nutrients at the household-level in the United States. The aim of this study is therefore to evaluate the environmental and economic impacts of conventional and advanced OWTSs with respect to their ability to remove total nitrogen (TN). Septic tank and drainfield materials were varied for conventional systems, and the advanced systems evaluated consisted of aerobic treatment units (ATUs) and passive nitrogen reduction systems (PNRSs) with nitrification and denitrification stages. Life cycle assessment and life cycle cost analysis were performed to evaluate OWTSs operating in different soil and temperature conditions. Nutrient management of the advanced OWTSs outperformed the conventional systems (96.7-100% vs. 61-65% TN removal), and resulted in less than 40% of the freshwater (0.06-0.14 vs. 0.37-0.40 kg P-eq/kg TN) and marine eutrophication (0.04-0.06 vs. 0.54-0.65 kg N-eq/kg TN). However, the tradeoff for nutrient management was higher life cycle costs ($101-$121 vs. $45-$58 USD 2015/kg TN) and environmental impacts for the remaining impact categories. Lastly, when the TN removed by the drainfield was <20%, the advanced system had lower impacts than conventional OWTSs across all impact categories except ecotoxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Diminished brain resilience syndrome: A modern day neurological pathology of increased susceptibility to mild brain trauma, concussion, and downstream neurodegeneration.

PubMed

Morley, Wendy A; Seneff, Stephanie

2014-01-01

The number of sports-related concussions has been steadily rising in recent years. Diminished brain resilience syndrome is a term coined by the lead author to describe a particular physiological state of nutrient functional deficiency and disrupted homeostatic mechanisms leading to increased susceptibility to previously considered innocuous concussion. We discuss how modern day environmental toxicant exposure, along with major changes in our food supply and lifestyle practices, profoundly reduce the bioavailability of neuro-critical nutrients such that the normal processes of homeostatic balance and resilience are no longer functional. Their diminished capacity triggers physiological and biochemical 'work around' processes that result in undesirable downstream consequences. Exposure to certain environmental chemicals, particularly glyphosate, the active ingredient in the herbicide, Roundup(®), may disrupt the body's innate switching mechanism, which normally turns off the immune response to brain injury once danger has been removed. Deficiencies in serotonin, due to disruption of the shikimate pathway, may lead to impaired melatonin supply, which reduces the resiliency of the brain through reduced antioxidant capacity and alterations in the cerebrospinal fluid, reducing critical protective buffering mechanisms in impact trauma. Depletion of certain rare minerals, overuse of sunscreen and/or overprotection from sun exposure, as well as overindulgence in heavily processed, nutrient deficient foods, further compromise the brain's resilience. Modifications to lifestyle practices, if widely implemented, could significantly reduce this trend of neurological damage.

Integrating nano- and microparticles in practical decontamination processes for water and sediments in a green technology approach

NASA Astrophysics Data System (ADS)

Eggen, Trine; Soran, Maria-Loredana

2015-12-01

Historically, pollution has been associated with heavy metals and hydrophobic persistent organic pollutants (POPs). This has changed. Today, legacy or emerging contaminants cover a vast number of compounds including industrial man-made chemicals, pesticides and pharmaceuticals in addition to inorganic elements and nanomaterials. These compounds are transferred to the environment via wastewater effluents and leachates and via sludge/biosolids such as fertilizers or soil amendments. Compared to previous POPs, today's legacy and emerging contaminants cover a broader spectrum of structures and properties, including a high number of persistent medium to highly water. For most emerging contaminants, neither the environmental transfer and residue nor the short- and long ecotoxicological and human adverse effects are known. Thus, it's time for precautionary acting and to replace conventional treatment processes originally designed for removal of organic matter and nutrients with processes suitable for removal of hazardous chemicals with a wide range of properties before entering water and terrestrial recipients.

Optimization of A(2)O BNR processes using ASM and EAWAG Bio-P models: model performance.

PubMed

El Shorbagy, Walid E; Radif, Nawras N; Droste, Ronald L

2013-12-01

This paper presents the performance of an optimization model for a biological nutrient removal (BNR) system using the anaerobic-anoxic-oxic (A(2)O) process. The formulated model simulates removal of organics, nitrogen, and phosphorus using a reduced International Water Association (IWA) Activated Sludge Model #3 (ASM3) model and a Swiss Federal Institute for Environmental Science and Technology (EAWAG) Bio-P module. Optimal sizing is attained considering capital and operational costs. Process performance is evaluated against the effect of influent conditions, effluent limits, and selected parameters of various optimal solutions with the following results: an increase of influent temperature from 10 degrees C to 25 degrees C decreases the annual cost by about 8.5%, an increase of influent flow from 500 to 2500 m(3)/h triples the annual cost, the A(2)O BNR system is more sensitive to variations in influent ammonia than phosphorus concentration and the maximum growth rate of autotrophic biomass was the most sensitive kinetic parameter in the optimization model.

Aerobic sludge granulation for simultaneous anaerobic decolorization and aerobic aromatic amines mineralization for azo dye wastewater treatment.

PubMed

Yan, Lawrence K Q; Fung, Ka Y; Ng, Ka M

2018-06-01

In this study, the capability of using aerobic granules to undergo simultaneous anaerobic decolorization and aerobic aromatic amines degradation was demonstrated for azo dye wastewater treatment. An integrated acclimation-granulation process was devised, with Mordant Orange 1 as the model pollutant. Performance tests were carried out in a batch column reactor to evaluate the effect of various operating parameters. The optimal condition was to use 1.0-1.7 mm (1.51 ± 0.33 mm) granules, 5 g/L biomass, and 4000 mg/L organics as nutrient; and supplement the wastewater with 1  mg/L dissolved oxygen. This led to a dye mineralization of 61 ± 2%, an anaerobic dye removal of 88 ± 1%, and an aerobic aromatic amines removal of 70 ± 3% within 48 h. This study showed that simultaneous anaerobic/aerobic process by aerobic granules could be a possible alternative to the conventional activated sludge process.

Sequential nutrient uptake as a potential mechanism for phytoplankton to maintain high primary productivity and balanced nutrient stoichiometry

NASA Astrophysics Data System (ADS)

Yin, Kedong; Liu, Hao; Harrison, Paul J.

2017-05-01

We hypothesize that phytoplankton have the sequential nutrient uptake strategy to maintain nutrient stoichiometry and high primary productivity in the water column. According to this hypothesis, phytoplankton take up the most limiting nutrient first until depletion, continue to draw down non-limiting nutrients and then take up the most limiting nutrient rapidly when it is available. These processes would result in the variation of ambient nutrient ratios in the water column around the Redfield ratio. We used high-resolution continuous vertical profiles of nutrients, nutrient ratios and on-board ship incubation experiments to test this hypothesis in the Strait of Georgia. At the surface in summer, ambient NO3- was depleted with excess PO43- and SiO4- remaining, and as a result, both N : P and N : Si ratios were low. The two ratios increased to about 10 : 1 and 0. 45 : 1, respectively, at 20 m. Time series of vertical profiles showed that the leftover PO43- continued to be removed, resulting in additional phosphorus storage by phytoplankton. The N : P ratios at the nutricline in vertical profiles responded differently to mixing events. Field incubation of seawater samples also demonstrated the sequential uptake of NO3- (the most limiting nutrient) and then PO43- and SiO4- (the non-limiting nutrients). This sequential uptake strategy allows phytoplankton to acquire additional cellular phosphorus and silicon when they are available and wait for nitrogen to become available through frequent mixing of NO3- (or pulsed regenerated NH4). Thus, phytoplankton are able to maintain high productivity and balance nutrient stoichiometry by taking advantage of vigorous mixing regimes with the capacity of the stoichiometric plasticity. To our knowledge, this is the first study to show the in situ dynamics of continuous vertical profiles of N : P and N : Si ratios, which can provide insight into the in situ dynamics of nutrient stoichiometry in the water column and the inference of the transient status of phytoplankton nutrient stoichiometry in the coastal ocean.

A study on the use of the BioBall® as a biofilm carrier in a sequencing batch reactor.

PubMed

Masłoń, Adam; Tomaszek, Janusz A

2015-11-01

Described in this study are experiments conducted to evaluate the removal of organics and nutrients from synthetic wastewater by a moving bed sequencing batch biofilm reactor using BioBall® carriers as biofilm media. The work involving a 15L-laboratory scale MBSBBR (moving bed sequencing batch biofilm reactor) model showed that the wastewater treatment system was based on biochemical processes taking place with activated sludge and biofilm microorganisms developing on the surface of the BioBall® carriers. Classical nitrification and denitrification and the typical enhanced biological phosphorus removal process were achieved in the reactor analyzed, which operated with a volumetric organic loading of 0.84-0.978gCODL(-1)d(-1). The average removal efficiencies for COD, total nitrogen and total phosphorus were found to be 97.7±0.5%, 87.8±2.6% and 94.3±1.3%, respectively. Nitrification efficiency reached levels in the range 96.5-99.7%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Cultivation of the Marine Macroalgae Chaetomorpha linum in Municipal Wastewater for Nutrient Recovery and Biomass Production.

PubMed

Ge, Shijian; Champagne, Pascale

2017-03-21

Compared to microalgae, macroalgae are larger in size, thereby imposing lower separation and drying costs. This study demonstrates the feasibility of cultivating macroalgae Chaetomorpha linum in different types of municipal wastewaters, their ability to remove nutrient and their biomass composition for downstream biofuel production. Screening experiments indicated that C. linum grew well on primary (PW) and secondary wastewaters (SW), as well as centrate wastewater (CW) diluted to less than 20%. In a subsequent experiment, a step feeding approach was found to significantly increase biomass productivity to 10.7 ± 0.2 g AFDW·m -2 ·d -1 (p < 0.001), a 26.5% improvement in comparison to the control with single feeding, when grown on 10-CW; meanwhile, nitrogen and phosphorus removal efficiencies rose to 86.8 ± 1.1% (p < 0.001) and 92.6 ± 0.2% (p < 0.001), respectively. The CO 2 -supplemented SW cultures (10.1 ± 0.4 g AFDW·m -2 ·d -1 ) were 1.20 times more productive than the corresponding controls without CO 2 supplementation (p < 0.001); however, similar improvements were not observed in PW (p = 0.07) and 10-CW cultures (p = 0.07). Moreover, wastewater type and nutrient concentration influenced biomass composition (protein, carbohydrate and lipid). These findings indicate that the application of the macroalgae C. linum could represent an effective wastewater treatment alternative that could also provide a feedstock for downstream processing to biofuels.

Simultaneous nitrogen, phosphorous, and hardness removal from reverse osmosis concentrate by microalgae cultivation.

PubMed

Wang, Xiao-Xiong; Wu, Yin-Hu; Zhang, Tian-Yuan; Xu, Xue-Qiao; Dao, Guo-Hua; Hu, Hong-Ying

2016-05-01

While reverse osmosis (RO) is a promising technology for wastewater reclamation, RO concentrate (ROC) treatment and disposal are important issues to consider. Conventional chemical and physical treatment methods for ROC present certain limitations, such as relatively low nitrogen and phosphorus removal efficiencies as well as the requirement of an extra process for hardness removal. This study proposes a novel biological approach for simultaneous removal of nitrogen, phosphorus, and calcium (Ca(2+)) and magnesium (Mg(2+)) ions from the ROC of municipal wastewater treatment plants by microalgal cultivation and algal biomass production. Two microalgae strains, Chlorella sp. ZTY4 and Scenedesmus sp. LX1, were used for batch cultivation of 14-16 days. Both strains grew well in ROC with average biomass production of 318.7 mg/L and lipid contents up to 30.6%, and nitrogen and phosphorus could be effectively removed with efficiencies of up to 89.8% and 92.7%, respectively. Approximately 55.9%-83.7% Ca(2+) could be removed from the system using the cultured strains. Mg(2+) removal began when Ca(2+) precipitation ceased, and the removal efficiency of the ion could reach up to 56.0%. The most decisive factor influencing Ca(2+) and Mg(2+) removal was chemical precipitation with increases in pH caused by algal growth. The results of this study provide a new biological approach for removing nitrogen, phosphorous, and hardness from ROC. The results suggest that microalgal cultivation presents new opportunities for applying an algal process to ROC treatment. The proposed approach serves dual purposes of nutrient and hardness reduction and production of lipid rich micro-algal biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improvement in the productivity of xylooligosaccharides from waste medium after mushroom cultivation by hydrothermal treatment with suitable pretreatment.

PubMed

Sato, Nobuaki; Shinji, Kazunori; Mizuno, Masahiro; Nozaki, Kouichi; Suzuki, Masayuki; Makishima, Satoshi; Shiroishi, Masahiro; Onoda, Takeru; Takahashi, Fumihiro; Kanda, Takahisa; Amano, Yoshihiko

2010-08-01

The effective xylooligosaccharides (XOs) production from the waste medium after mushroom cultivation (WM) was investigated. The WM contains rich nutrients (protein, etc.) which induce Maillard reaction with reducing sugars under hydrothermal conditions. To improve the productivity of XOs, the suitable pretreatment combined with washing and grinding was investigated, and subsequently hydrothermal treatment was demonstrated with batch type and continuous flow type reactor. The washing pretreatment with hot water of 60 degrees C was effective to remove nutrients from the WM, and it led to prevent brownish discoloration on the hydrothermal treatment. On the basis of experimental data, industrial XOs production processes consisting of the pretreatment, hydrothermal treatment and purification step was designed. During the designed process, 2.3 kg-dry of the purified XOs was produced from 30 kg-wet of the WM (15% yield as dry basis weight). Theoretical yield of XOs attained to 48% as xylan weight in the WM. (c) 2010 Elsevier Ltd. All rights reserved.

Phycoremediation of Heavy Metals in Wet Market Wastewater

NASA Astrophysics Data System (ADS)

Apandi, Najeeha; Saphira Radin Mohamed, Radin Maya; Al-Gheethi, Adel; Latiffi, Atikah; Nor Hidayah Arifin, Siti; Gani, Paran

2018-04-01

The efficiency of phycoremediation using microalgae for removing nutrients and heavy metals from wastewaters has been proved. However, the differences in the composition of wastewaters as well as microalgae species play an important role in the efficient of this process. Therefore, the present study aimed to investigate the effectiveness of Scenedesmus sp. to removal of heavy metals from wet market wastewater. Scenedesmus sp. was inoculated with 106 cells/mL into each wet market wastewater concentration included 10, 25, 50, 75 and 100% and incubated for 18 days. The highest growth rate was recorded in 50% WM with a maximum dry weight of 2006 mg L-1 which subsequently removed 93.06% of Cd, 91.5% of Cr, 92.47% of Fe, 92.40% of Zn. These findings reflected the high potential of Scenedesmus sp. in the treatment of wet market wastewater and production microalgae biomass.

WATER LEVEL AND OXYGEN DELIVERY/UTILIZATION IN POROUS SALT MARSH SEDIMENTS

EPA Science Inventory

Increasing terrestrial nutrient inputs to coastal waters is a global water quality issue worldwide, and salt marshes may provide a valuable nutrient buffer, either by direct removal or by smoothing out pulse inputs between sources and sensitive estuarine habitats. A major challen...

Nutrient removal of agricultural drainage water using algal turf scrubbers and solar power

USDA-ARS?s Scientific Manuscript database

Restoration of the Chesapeake Bay poses significant challenges because of increasing population pressure, conversion of farmland to urban/suburban development, and the expense of infrastructure needed to achieve significant and sustained nutrient reductions from agricultural and urban sources. One ...

Hydrology in a peaty high marsh: hysteretic flow and biogeochemical implications

EPA Science Inventory

Terrestrial nutrient input to coastal waters is a critical water quality problem worldwide, and salt marshes may provide a valuable nutrient buffer (either by removal or by smoothing out pulse inputs) between terrestrial sources and sensitive estuarine habitats. One of the major...

Laboratory experiments on simultaneous removal of K and P from synthetic and real urine for nutrient recycle by crystallization of magnesium-potassium-phosphate-hexahydrate in a draft tube and baffle reactor.

PubMed

Xu, Kangning; Wang, Chengwen; Wang, Xiaoxue; Qian, Yi

2012-06-01

The simultaneous removal of K and P from urine for nutrient recycling by crystallization of magnesium potassium phosphate hexahydrate (MPP) in a laboratory-scale draft tube and baffle reactor (DTBR) is investigated. Results show that mixing speed and hydraulic retention time are important operating factors that influence crystallization and crystal settlement. Slurry should be discharged at a crystal retention time of 11 h to maintain fluidity in the reactor. Further applications of the DTBR using real urine (pretreated by ammonia stripping and diluted five times) showed that 76% K and 68% P were recycled to multi-nutrient products. The crystals collected were characterized and confirmed mainly as a mixture of magnesium ammonium phosphate hexahydrate, MPP, and magnesium sodium phosphate heptahydrate. Results indicate that the DTBR effectively achieved the simultaneous recycling of K and P from urine to multi-nutrient products through MPP crystallization. Copyright © 2012 Elsevier Ltd. All rights reserved.

Yield and Nutrient Removal by Whole-Tree Harvest of a Young Bottomland Hardwood Stand

Treesearch

John K. Francis

1984-01-01

The yield and nutrient withdrawal by whole-tree harvest of young bottomland hardwoods has heretofore been unknown. In this study of intensive harvest, samples of chipped whole trees and soil from 16 test plots were analyzed for nutrient content. Eighty-two percent of the stems and 59 percent of the dry weight were green ash. The balance was divided among a number of...

Using extension phosphorus uptake research to improve Idaho's nutrient management planning program

USDA-ARS?s Scientific Manuscript database

Irrigated silage corn is the main crop used for phosphorus removal; however little is known about the actual amounts of phosphorus removed under southern Idaho growing conditions. The purpose of this study was to survey phosphorus removal by irrigated corn grown for silage in southern Idaho under va...

Studies on crude oil removal from pebbles by the application of biodiesel.

PubMed

Xia, Wen-xiang; Xia, Yan; Li, Jin-cheng; Zhang, Dan-feng; Zhou, Qing; Wang, Xin-ping

2015-02-15

Oil residues along shorelines are hard to remove after an oil spill. The effect of biodiesel to eliminate crude oil from pebbles alone and in combination with petroleum degrading bacteria was investigated in simulated systems. Adding biodiesel made oil detach from pebbles and formed oil-biodiesel mixtures, most of which remained on top of seawater. The total petroleum hydrocarbon (TPH) removal efficiency increased with biodiesel quantities but the magnitude of augment decreased gradually. When used with petroleum degrading bacteria, the addition of biodiesel (BD), nutrients (NUT) and BD+NUT increased the dehydrogenase activity and decreased the biodegradation half lives. When BD and NUT were replenished at the same time, the TPH removal efficiency was 7.4% higher compared to the total improvement of efficiency when BD and NUT was added separately, indicating an additive effect of biodiesel and nutrients on oil biodegradation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Response surface analysis and modeling of n-alkanes removal through bioremediation of weathered crude oil.

PubMed

Mohajeri, Leila; Abdul Aziz, Hamidi; Ali Zahed, Mohammad; Mohajeri, Soraya; Mohamed Kutty, Shamsul Rahman; Hasnain Isa, Mohamed

2011-01-01

Central composite design (CCD) and response surface methodology (RSM) were employed to optimize four important variables, i.e. amounts of oil, bacterial inoculum, nitrogen and phosphorus, for the removal of selected n-alkanes during bioremediation of weathered crude oil in coastal sediments using laboratory bioreactors over a 60 day experimentation period. The reactors contained 1 kg soil with different oil, microorganisms and nutrients concentrations. The F Value of 26.89 and the probability value (P < 0.0001) demonstrated significance of the regression model. For crude oil concentration of 2, 16 and 30 g per kg sediments and under optimized conditions, n-alkanes removal was 97.38, 93.14 and 90.21% respectively. Natural attenuation removed 30.07, 25.92 and 23.09% n-alkanes from 2, 16 and 30 g oil/kg sediments respectively. Excessive nutrients addition was found to inhibit bioremediation.

Long-term records reveal decoupling of nitrogen and phosphorus cycles in a large, urban lake in response to an extreme rainfall event

NASA Astrophysics Data System (ADS)

Corman, J. R.; Loken, L. C.; Oliver, S. K.; Collins, S.; Butitta, V.; Stanley, E. H.

2017-12-01

Extreme events can play powerful roles in shifting ecosystem processes. In lakes, heavy rainfall can transport large amounts of particulates and dissolved nutrients into the water column and, potentially, alter biogeochemical cycling. However, the impacts of extreme rainfall events are often difficult to study due to a lack of long-term records. In this paper, we combine daily discharge records with long-term lake water quality information collected by the North Temperate Lakes Long-Term Ecological Research (NTL LTER) site to investigate the impacts of extreme events on nutrient cycling in lakes. We focus on Lake Mendota, an urban lake within the Yahara River Watershed in Madison, Wisconsin, USA, where nutrient data are available at least seasonally from 1995 - present. In June 2008, precipitation amounts in the Yahara watershed were 400% above normal values, triggering the largest discharge event on record for the 40 years of monitoring at the streamgage station; hence, we are able to compare water quality records before and after this event as a case study of how extreme rain events couple or decouple lake nutrient cycling. Following the extreme event, the lake-wide mass of nitrogen and phosphorus increased in the summer of 2008 by 35% and 21%, respectively, shifting lake stoichiometry by increasing N:P ratios (Figure 1). Nitrogen concentrations remained elevated longer than phosphorus, suggesting (1) that nitrogen inputs into the lake were sustained longer than phosphorus (i.e., a "smear" versus "pulse" loading of nitrogen versus phosphorus, respectively, in response to the extreme event) and/or (2) that in-lake biogeochemical processing was more efficient at removing phosphorus compared to nitrogen. While groundwater loading data are currently unavailable to test the former hypothesis, preliminary data from surficial nitrogen and phosphorus loading to Lake Mendota (available for 2011 - 2013) suggest that nitrogen removal efficiency is less than phosphorus, supporting the latter hypothesis. As climate change is expected to increase the frequency of extreme events, continued monitoring of lakes is needed to understand biogeochemical responses and when and how water quality threats may occur.

Microalgae treatment removes nutrients and reduces ecotoxicity of diluted piggery digestate.

PubMed

Franchino, Marta; Tigini, Valeria; Varese, Giovanna Cristina; Mussat Sartor, Rocco; Bona, Francesca

2016-11-01

Liquid digestate is considered as an important by-product of anaerobic digestion of agriculture wastes. Currently, it is very often directly spread on local agricultural land. Yet recently concerns on its environmental risk of this processing has begun to rise. On the other hand, investigations on the effectiveness of microalgae for wastewater treatment have started to consider also this complex matrix. In this study, we cultured the green alga Chlorella vulgaris in diluted digestate coming from the anaerobic digestion of pig slurry and corn, with the aim to significantly reduce its toxicity and its very high nutrient concentration. For this purpose, a battery of toxicity tests composed of four acute and two chronic bioassays was applied after the alga cultivation. Results were compared with those obtained in the initial characterization of the digestate. Results show that highly diluted piggery digestate can be a suitable medium for culturing microalgae, as we obtained a high removal efficiency (>90%) for ammonia, total nitrogen and phosphate, though after a few days phosphorus limitation occurred. Toxicity was significantly reduced for all the organisms tested. Possible solutions for optimizing this approach avoiding high dilution rates are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Arctic water tracks retain phosphorus and transport ammonium

NASA Astrophysics Data System (ADS)

Harms, T.; Cook, C. L.; Wlostowski, A. N.; Godsey, S.; Gooseff, M. N.

2017-12-01

Hydrologic flowpaths propagate biogeochemical signals among adjacent ecosystems, but reactions may attenuate signals by retaining, removing, or transforming dissolved and suspended materials. The theory of nutrient spiraling describes these simultaneous reaction and transport processes, but its application has been limited to stream channels. We applied nutrient spiraling theory to water tracks, zero-order channels draining Arctic hillslopes that contain perennially saturated soils and flow at the surface either perennially or in response to precipitation. In the Arctic, experimental warming results in increased availability of nitrogen, the limiting nutrient for hillslope vegetation at the study site, which may be delivered to aquatic ecosystems by water tracks. Increased intensity of rain events, deeper snowpack, earlier snowmelt, and increasing thaw depth resulting from climate change might support increased transport of nutrients, but the reactive capacity of hillslope flowpaths, including sorption and uptake by plants and microbes, could counter transport to regulate solute flux. Characteristics of flowpaths might influence the opportunity for reaction, where slower flowpaths increase the contact time between solutes and soils or roots. We measured nitrogen and phosphorus uptake and transient storage of water tracks through the growing season and found that water tracks retain inorganic phosphorus, but transport ammonium. Nutrient uptake was unrelated to transient storage, suggesting high capacity for nutrient retention by shallow organic soils and vegetation. These observations indicate that increased availability of ammonium, the biogeochemical signal of warming tundra, is propagated by hillslope flowpaths, whereas water tracks attenuate delivery of phosphorus to aquatic ecosystems, where its availability typically limits production.

River delta network hydraulic residence time distributions and their role in coastal nutrient biogeochemistry

NASA Astrophysics Data System (ADS)

Hiatt, M. R.; Castaneda, E.; Twilley, R.; Hodges, B. R.; Passalacqua, P.

2015-12-01

River deltas have the potential to mitigate increased nutrient loading to coastal waters by acting as biofilters that reduce the impact of nutrient enrichment on downstream ecosystems. Hydraulic residence time (HRT) is known to be a major control on biogeochemical processes and deltaic floodplains are hypothesized to have relatively long HRTs. Hydrological connectivity and delta floodplain inundation induced by riverine forces, tides, and winds likely alter surface water flow patterns and HRTs. Since deltaic floodplains are important elements of delta networks and receive significant fluxes of water, sediment, and nutrients from distributary channels, biogeochemical transformations occurring within these zones could significantly reduce nutrient loading to coastal receiving waters. However, network-scale estimates of HRT in river deltas are lacking and little is known about the effects of tides, wind, and the riverine input on the HRT distribution. Subsequently, there lacks a benchmark for evaluating the impact of engineered river diversions on coastal nutrient ecology. In this study, we estimate the HRT of a coastal river delta by using hydrodynamic modeling supported by field data and relate the HRT to spatial and temporal patterns in nitrate levels measured at discrete stations inside a delta island at Wax Lake Delta. We highlight the control of the degree of hydrological connectivity between distributary channels and interdistributary islands on the network HRT distribution and address the roles of tides and wind on altering the shape of the distribution. We compare the observed nitrate concentrations to patterns of channel-floodplain hydrological connectivity and find this connectivity to play a significant role in the nutrient removal. Our results provide insight into the potential role of deltaic wetlands in reducing the nutrient loading to near-shore waters in response to large-scale river diversions.

Effects of Successive Harvests on Soil Nutrient Stocks in Established Tropical Plantation Forests

NASA Astrophysics Data System (ADS)

Mendoza, L.; McMahon, D.; Jackson, R. B.

2017-12-01

Large-scale plantation forests in tropical regions alter biogeochemical processes, raising concerns about the long-term sustainability of this land use. Current commercial practices result in nutrient export with removed biomass that may not be balanced by fertilizer application. Consequent changes in a landscape's nutrient distributions can affect the growth of future plantations or other vegetation. Prior studies have reported changes in soil chemical and physical properties when plantation forests replace pastures or native vegetation, but few have examined the impacts of multiple harvest cycles following plantation establishment. This study analyzed macronutrient and carbon content of soil samples from the world's most productive plantation forests, in southeastern Brazil, to understand the long-term effects of plantation forests on soil nutrient stocks and soil fertility. Soil was collected from Eucalyptus plantation sites and adjacent vegetation in 2004 and again in 2016, after at least one full cycle of harvesting and replanting. We found that within surface soil (0-10 cm) Mg and N did not change significantly and C, P, K and Ca concentrations generally increased, but to varying extents within individual management units. This trend of increasing nutrient concentrations suggests that additional harvests do not result in cumulative nutrient depletion. However, large changes in Ca and K concentrations in individual plantation units indicate that added fertilizer does not consistently accumulate in the surface soil. Analysis of deeper soil layers and comparison to unfertilized vegetation will help to determine the fate of fertilizers and native soil nutrients in repeatedly harvested plantations. These results address the necessity of long-term investigation of nutrient changes to better understand and determine the impacts of different types of land use in the tropics.

Wetland management reduces sediment and nutrient loading to the upper Mississippi river.

PubMed

Kreiling, Rebecca M; Schubauer-Berigan, Joseph P; Richardson, William B; Bartsch, Lynn A; Hughes, Peter E; Cavanaugh, Jennifer C; Strauss, Eric A

2013-01-01

Restored riparian wetlands in the Upper Mississippi River basin have potential to remove sediment and nutrients from tributaries before they flow into the Mississippi River. For 3 yr we calculated retention efficiencies of a marsh complex, which consisted of a restored marsh and an adjacent natural marsh that were connected to Halfway Creek, a small tributary of the Mississippi. We measured sediment, N, and P removal through a mass balance budget approach, N removal through denitrification, and N and P removal through mechanical soil excavation. The marsh complex had average retention rates of approximately 30 Mg sediment ha yr, 26 kg total N ha yr, and 20 kg total P ha yr. Water flowed into the restored marsh only during high-discharge events. Although the majority of retention occurred in the natural marsh, portions of the natural marsh were hydrologically disconnected at low discharge due to historical over-bank sedimentation. The natural marsh removed >60% of sediment, >10% of P, and >5% of N loads (except the first year, when it was a N source). The marsh complex was a source of NH and soluble reactive P. The average denitrification rate for the marsh complex was 2.88 mg N m h. Soil excavation removed 3600 Mg of sediment, 5.6 Mg of N, and 2.7 Mg of P from the restored marsh. The marsh complex was effective in removing sediment and nutrients from storm flows; however, retention could be increased if more water was diverted into both restored and natural marshes before entering the river. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The effects of CO₂ addition along a pH gradient on wastewater microalgal photo-physiology, biomass production and nutrient removal.

PubMed

Sutherland, Donna L; Howard-Williams, Clive; Turnbull, Matthew H; Broady, Paul A; Craggs, Rupert J

2015-03-01

Carbon limitation in domestic wastewater high rate algal ponds is thought to constrain microalgal photo-physiology and productivity, particularly in summer. This paper investigates the effects of CO₂ addition along a pH gradient on the performance of wastewater microalgae in high rate algal mesocosms. Performance was measured in terms of light absorption, electron transport rate, photosynthetic efficiency, biomass production and nutrient removal efficiency. Light absorption by the microalgae increased by up to 128% with increasing CO₂ supply, while a reduction in the package effect meant that there was less internal self-shading thereby increasing the efficiency of light absorption. CO₂ augmentation increased the maximum rate of both electron transport and photosynthesis by up to 256%. This led to increased biomass, with the highest yield occurring at the highest dissolved inorganic carbon/lowest pH combination tested (pH 6.5), with a doubling of chlorophyll-a (Chl-a) biomass while total microalgal biovolume increased by 660% in Micractinium bornhemiense and by 260% in Pediastrum boryanum dominated cultures. Increased microalgal biomass did not off-set the reduction in ammonia volatilisation in the control and overall nutrient removal was lower with CO₂ than without. Microalgal nutrient removal efficiency decreased as pH decreased and may have been related to decreased Chl-a per cell. This experiment demonstrated that CO₂ augmentation increased microalgal biomass in two distinct communities, however, care must be taken when interpreting results from standard biomass measurements with respect to CO₂ augmentation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Monitoring of Commitment, Blocking, and Continuation of Nutrient Germination of Individual Bacillus subtilis Spores

PubMed Central

Zhang, Pengfei; Liang, Jintao; Yi, Xuan; Setlow, Peter

2014-01-01

Short exposures of Bacillus spores to nutrient germinants can commit spores to germinate when germinants are removed or their binding to the spores' nutrient germinant receptors (GRs) is inhibited. Bacillus subtilis spores were exposed to germinants for various periods, followed by germinant removal to prevent further commitment. Release of spore dipicolinic acid (DPA) was then measured by differential interference contrast microscopy to monitor germination of multiple individual spores, and spores did not release DPA after 1 to 2 min of germinant exposure until ∼7 min after germinant removal. With longer germinant exposures, percentages of committed spores with times for completion of DPA release (Trelease) greater than the time of germinant removal (Tb) increased, while the time Tlag − Tb, where Tlag represents the time when rapid DPA release began, was decreased but rapid DPA release times (ΔTrelease = Trelease − Tlag) were increased; Factors affecting average Trelease values and the percentages of committed spores were germinant exposure time, germinant concentration, sporulation conditions, and spore heat activation, as previously shown for commitment of spore populations. Surprisingly, germination of spores given a 2nd short germinant exposure 30 to 45 min after a 1st exposure of the same duration was significantly higher than after the 1st exposure, but the number of spores that germinated in the 2nd germinant exposure decreased as the interval between germinant exposures increased up to 12 h. The latter results indicate that spores have some memory, albeit transient, of their previous exposure to nutrient germinants. PMID:24769693

Wetland Management Reduces Sediment and Nutrient Loading to the Upper Mississippi River

EPA Science Inventory

Restored riparian wetlands in the Upper Mississippi River basin have the potential to remove sediment and nutrients from tributaries before they flow into the Mississippi River. For 3 yr we calculated retention efficiencies of a marsh complex, which consisted of a restored marsh...

Nutrient Removal and Resource Recovery: Effect on Life Cycle Cost and Environmental Impacts of Small Scale Wastewater Treatment

EPA Science Inventory

Many communities across the U.S. are required to upgrade wastewater treatment plants (WWTP) to meet increasingly stringent nutrient effluent standards. However, increased capital, energy and chemical requirements of upgrades create potential trade-offs between eutrophication pote...

Mass algal culture system

DOEpatents

Raymond, Lawrence P.

1982-01-01

An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

Mass algal culture system

DOEpatents

Raymond, Lawrence P.

1981-01-01

An apparatus and process for the culture of algae in a liquid medium is disclosed. The medium circulates through an open trough and is exposed to an atmosphere which is temperature regulated. The nutrient content of the liquid medium is regulated to control the chemical composition growth and reproduction characteristics of the cultured algae. Before it is allowed to strike the medium, sunlight is passed through a filter to remove wavelengths which are not photosynthetically active. Heat energy can be recovered from the filter.

Evaluation of the Effects of AFFF Inputs on the VIP Biological Nutrient Removal Process and Pass-Through Toxicity.

DTIC Science & Technology

1999-01-01

AFFF ( aqueous film - forming foam ), is widely used by the U.S. Navy in fire fighting water to improve the ability to control petroleum...Chan, D. B., (1978). " Disposal of Wastewater Containing Aqueous Film Forming Foam ." Technical Memorandum No. M-54-78-06, Civil Engineering...Inmand, R.C. (1975). "Biodegradability and Toxicity of ANSUL K74-100, Aqueous Film Forming Foam ." Report No. EHL(K) 75-3, USAF Environmental

Comparative renal anatomy of exotic species.

PubMed

Holz, Peter H; Raidal, Shane R

2006-01-01

All living organisms consume nutrients that are required for the production of both tissue and energy. The waste products of this process include nitrogenous materials and inorganic salts. They are removed from the body by excretory organs, which in vertebrate shave developed into kidneys and into salt glands in some birds and reptiles. Many invertebrates use a series of excretory organs called nephridia to perform the same function. Even though they perform similar functions, there is no evolutionary connection between invertebrate nephridia and vertebrate kidneys. Both evolved independently.

Nitrogen Removal from Landfill Leachate by Microalgae.

PubMed

Pereira, Sérgio F L; Gonçalves, Ana L; Moreira, Francisca C; Silva, Tânia F C V; Vilar, Vítor J P; Pires, José C M

2016-11-17

Landfill leachates result from the degradation of solid residues in sanitary landfills, thus presenting a high variability in terms of composition. Normally, these effluents are characterized by high ammoniacal-nitrogen (N-NH₄⁺) concentrations, high chemical oxygen demands and low phosphorus concentrations. The development of effective treatment strategies becomes difficult, posing a serious problem to the environment. Phycoremediation appears to be a suitable alternative for the treatment of landfill leachates. In this study, the potential of Chlorella vulgaris for biomass production and nutrients (mainly nitrogen and phosphorus) removal from different compositions of a landfill leachate was evaluated. Since microalgae also require phosphorus for their growth, different loads of this nutrient were evaluated, giving the following N:P ratios: 12:1, 23:1 and 35:1. The results have shown that C. vulgaris was able to grow in the different leachate compositions assessed. However, microalgal growth was higher in the cultures presenting the lowest N-NH₄⁺ concentration. In terms of nutrients uptake, an effective removal of N-NH₄⁺ and phosphorus was observed in all the experiments, especially in those supplied with phosphorus. Nevertheless, N-NO₃ - removal was considered almost negligible. These promising results constitute important findings in the development of a bioremediation technology for the treatment of landfill leachates.

Nitrogen Removal from Landfill Leachate by Microalgae

PubMed Central

Pereira, Sérgio F. L.; Gonçalves, Ana L.; Moreira, Francisca C.; Silva, Tânia F. C. V.; Vilar, Vítor J. P.; Pires, José C. M.

2016-01-01

Landfill leachates result from the degradation of solid residues in sanitary landfills, thus presenting a high variability in terms of composition. Normally, these effluents are characterized by high ammoniacal-nitrogen (N–NH4+) concentrations, high chemical oxygen demands and low phosphorus concentrations. The development of effective treatment strategies becomes difficult, posing a serious problem to the environment. Phycoremediation appears to be a suitable alternative for the treatment of landfill leachates. In this study, the potential of Chlorella vulgaris for biomass production and nutrients (mainly nitrogen and phosphorus) removal from different compositions of a landfill leachate was evaluated. Since microalgae also require phosphorus for their growth, different loads of this nutrient were evaluated, giving the following N:P ratios: 12:1, 23:1 and 35:1. The results have shown that C. vulgaris was able to grow in the different leachate compositions assessed. However, microalgal growth was higher in the cultures presenting the lowest N–NH4+ concentration. In terms of nutrients uptake, an effective removal of N–NH4+ and phosphorus was observed in all the experiments, especially in those supplied with phosphorus. Nevertheless, N–NO3− removal was considered almost negligible. These promising results constitute important findings in the development of a bioremediation technology for the treatment of landfill leachates. PMID:27869676

A Leptolyngbya-based microbial consortium for agro-industrial wastewaters treatment and biodiesel production.

PubMed

Tsolcha, Olga N; Tekerlekopoulou, Athanasia G; Akratos, Christos S; Antonopoulou, Georgia; Aggelis, George; Genitsaris, Savvas; Moustaka-Gouni, Maria; Vayenas, Dimitrios V

2018-04-22

A mixed cyanobacterial-mixotrophic algal population, dominated by the filamentous cyanobacterium Leptolyngbya sp. and the microalga Ochromonas (which contributed to the total photosynthetic population with rates of less than 5%), was studied under non-aseptic conditions for its efficiency to remove organic and inorganic compounds from different types of wastes/wastewaters while simultaneously producing lipids. Second cheese whey, poplar sawdust, and grass hydrolysates were used in lab-scale experiments, in photobioreactors that operated under aerobic conditions with different initial nutrient (C, N and P) concentrations. Nutrient removal rates, biomass productivity, and the maximum oil production rates were determined. The highest lipid production was achieved using the biologically treated dairy effluent (up to 14.8% oil in dry biomass corresponding to 124 mg L -1 ) which also led to high nutrient removal rates (up to 94%). Lipids synthesized by the microbial consortium contained high percentages of saturated and mono-unsaturated fatty acids (up to 75% in total lipids) for all the substrates tested, which implies that the produced biomass may be harnessed as a source of biodiesel.

Nutrient and suspended solids removal from petrochemical wastewater via microalgal biofilm cultivation.

PubMed

Hodges, Alan; Fica, Zachary; Wanlass, Jordan; VanDarlin, Jessica; Sims, Ronald

2017-05-01

Wastewater derived from petroleum refining currently accounts for 33.6 million barrels per day globally. Few wastewater treatment strategies exist to produce value-added products from petroleum refining wastewater. In this study, mixed culture microalgal biofilm-based treatment of petroleum refining wastewater using rotating algae biofilm reactors (RABRs) was compared with suspended-growth open pond lagoon reactors for removal of nutrients and suspended solids. Triplicate reactors were operated for 12 weeks and were continuously fed with petroleum refining wastewater. Effluent wastewater was monitored for nitrogen, phosphorus, total suspended solids (TSS), and chemical oxygen demand (COD). RABR treatment demonstrated a statistically significant increase in removal of nutrients and suspended solids, and increase in biomass productivity, compared to the open pond lagoon treatment. These trends translate to a greater potential for the production of biomass-based fuels, feed, and fertilizer as value-added products. This study is the first demonstration of the cultivation of mixed culture biofilm microalgae on petroleum refining wastewater for the dual purposes of treatment and biomass production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nitrogen and organic carbon cycling processes in tidal marshes and shallow estuarine habitats

NASA Astrophysics Data System (ADS)

Bergamaschi, B. A.; Downing, B. D.; Pellerin, B. A.; Kraus, T. E. C.; Fleck, J.; Fujii, R.

2016-02-01

Tidal wetlands and shallow water habitats can be sites of high aquatic productivity, and they have the potential of exchanging this newly produced organic carbon with adjacent deeper habitats. Indeed, export of organic carbon from wetlands and shallow water habitats to pelagic food webs is one of the primary ecosystem functions targeted in tidal wetland restorations. Alternatively, wetlands and shallow water habitats can function as retention areas for nutrients due to the nutrient demand of emergent macrophytes and denitrification in anoxic zones. They can also remove phytoplankton and non-algal particles from the aquatic food webs because the shallower waters can result in higher rates of benthic grazing and higher settling due to lower water velocities. We conducted studies in wetland and channel sites in the San Francisco estuary (USA) to investigate the dynamics of nutrients and carbon production at a variety of temporal scales. We collected continuous time series of nutrients, oxygen, chlorophyll and pH in conjunction with continuous acoustic measurement of water velocity and discharge to provide mass controls and used simple biogeochemical models to assess rates. We found a high degree of temporal variability in individual systems, corresponding to, for example, changes in nutrient supply, water level, light level, wind, wind direction, and other physical factors. There was also large variability among the different systems, probably due to differences in flows and geomorphic features. We compare the aquatic productivity of theses environments and speculate as to the formative elements of each. Our findings demonstrate the complex interaction between physical, chemical, and biological factors that determine the type of production and degree of export from tidal wetlands and shallow water habitats, suggesting that a clearer picture of these processes is important for guiding future large scale restoration efforts.

Evaluation of simultaneous organic matters and nutrients removal from municipal wastewater using a novel bioreactor (D-A2O) system.

PubMed

Ye, Changbing; Zhou, Zhiming; Li, Ming; Liu, Qin; Xu, Tiantian; Li, Jia

2018-07-15

A novel bioreactor, the divisional influent dual-anaerobic-anoxic/oxic (D-A 2 O) system, was applied to treat municipal wastewater. This new system improved the removal efficiency of simultaneous organic matters and nutrients, and provided a reduction in the system's energy costs and sludge yield. Results from the reactor's 18 months of operation demonstrated the following optimal conditions for the 4 key parameters of the system: (1) a divisional ratio (DR) of 8:2 between the influent flow volumes fed into the anaerobic and anoxic tanks, (2) a hydraulic retention time (HRT) of 6 h, (3) a R:r ratio of 200%:100% between the mixed liquor return ratio (R) and the return activated sludge ratio (r), and (4) an alternative operating time (t A/B ) of 1 h for the A/B anaerobic-anoxia series. Under optimal conditions, the system showed a high removal efficiency for the chemical oxygen demand (COD), total nitrogen (TN), ammonia nitrogen (NH 3 -N), and total phosphorus (TP) removals, with the average removal efficiencies (with a standard deviation of less than 3%) being 95.23%, 80.64%, 90.42%, and 90.03%, respectively. The final concentration ranges of COD, TN, NH 3 -N, and TP in the effluent were 26-48 mg L -1 , 6.11-11.03 mg L -1 , 2.93-4.04 mg L -1 , and 0.21-0.45 mg L -1 , respectively. The concentrations of the pollutants in the effluent from the D-A 2 O system were lower than those required for Level 1A (Chinese quality of wastewater discharge standard GB18918-2002). According to the results, we concluded that the divisional influent dual-anaerobic-anoxic system (which integrated the A 2 O and sequencing batch reactor (SBR) process) was successfully provided sufficient carbon sources for denitrification and phosphorus uptake without external carbon addition. Compared to the conventional anaerobic-anoxic/oxic (A 2 O) process, the D-A 2 O system offers a high removal efficiency, simple operation, and significant energy saving of about 0.276 kWh m -3 based on the volume of the treated water. Therefore, the new D-A 2 O system has a strong potential for use in treatment plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Impacts of light shading and nutrient enrichment geo-engineering approaches on the productivity of a stratified, oligotrophic ocean ecosystem.

PubMed

Hardman-Mountford, Nick J; Polimene, Luca; Hirata, Takafumi; Brewin, Robert J W; Aiken, Jim

2013-12-06

Geo-engineering proposals to mitigate global warming have focused either on methods of carbon dioxide removal, particularly nutrient fertilization of plant growth, or on cooling the Earth's surface by reducing incoming solar radiation (shading). Marine phytoplankton contribute half the Earth's biological carbon fixation and carbon export in the ocean is modulated by the actions of microbes and grazing communities in recycling nutrients. Both nutrients and light are essential for photosynthesis, so understanding the relative influence of both these geo-engineering approaches on ocean ecosystem production and processes is critical to the evaluation of their effectiveness. In this paper, we investigate the relationship between light and nutrient availability on productivity in a stratified, oligotrophic subtropical ocean ecosystem using a one-dimensional water column model coupled to a multi-plankton ecosystem model, with the goal of elucidating potential impacts of these geo-engineering approaches on ecosystem production. We find that solar shading approaches can redistribute productivity in the water column but do not change total production. Macronutrient enrichment is able to enhance the export of carbon, although heterotrophic recycling reduces the efficiency of carbon export substantially over time. Our results highlight the requirement for a fuller consideration of marine ecosystem interactions and feedbacks, beyond simply the stimulation of surface blooms, in the evaluation of putative geo-engineering approaches.

Impacts of light shading and nutrient enrichment geo-engineering approaches on the productivity of a stratified, oligotrophic ocean ecosystem

PubMed Central

Hardman-Mountford, Nick J.; Polimene, Luca; Hirata, Takafumi; Brewin, Robert J. W.; Aiken, Jim

2013-01-01

Geo-engineering proposals to mitigate global warming have focused either on methods of carbon dioxide removal, particularly nutrient fertilization of plant growth, or on cooling the Earth's surface by reducing incoming solar radiation (shading). Marine phytoplankton contribute half the Earth's biological carbon fixation and carbon export in the ocean is modulated by the actions of microbes and grazing communities in recycling nutrients. Both nutrients and light are essential for photosynthesis, so understanding the relative influence of both these geo-engineering approaches on ocean ecosystem production and processes is critical to the evaluation of their effectiveness. In this paper, we investigate the relationship between light and nutrient availability on productivity in a stratified, oligotrophic subtropical ocean ecosystem using a one-dimensional water column model coupled to a multi-plankton ecosystem model, with the goal of elucidating potential impacts of these geo-engineering approaches on ecosystem production. We find that solar shading approaches can redistribute productivity in the water column but do not change total production. Macronutrient enrichment is able to enhance the export of carbon, although heterotrophic recycling reduces the efficiency of carbon export substantially over time. Our results highlight the requirement for a fuller consideration of marine ecosystem interactions and feedbacks, beyond simply the stimulation of surface blooms, in the evaluation of putative geo-engineering approaches. PMID:24132201

Biophysical Controls on Carbon Cycling in Restored and Unrestored Urban Streams

NASA Astrophysics Data System (ADS)

Larsen, L. G.; Harvey, J. W.; Singh, J. D.; Sinclair, G. A.; Langston, T.; Maglio, M. M.

2012-12-01

Stream restoration is a multibillion dollar industry, yet how restoration impacts the ecological functioning of streams remains poorly understood. Because stream restoration may alter numerous biophysical controls, including light availability (through tree removal during bank regrading), hydraulics, sediment characteristics, and/or nutrient concentrations, it can be challenging to achieve a general understanding of how different aspects of stream restoration design influence ecosystem function (e.g., carbon cycling). In this study we combined strategies of continuously monitoring hydrology, turbidity, and dissolved oxygen at a station with spatially distributed but temporally sparse synoptic sampling to understand how restoration and land-use impact carbon fixation and respiration in urban streams. The study was performed over three years in three adjacent 3rd-4th order stream reaches in the urban Chesapeake Bay watershed, one of which was restored in 2002 using the ubiquitous Natural Channel Design method. By parsing the dissolved oxygen time series into contributions from respiration and gross primary production, we found the unrestored urban reach to be the most heterotrophic. It removed two times more carbon from the stream to the atmosphere than an unrestored suburban stream that was nutrient impacted and five times more carbon than the restored urban stream. The synoptic sampling revealed that nutrients, light, and hydrodynamic disturbance were the primary controls on carbon fixation and respiration, with fine sediment also exhibiting importance, likely as a vehicle for nutrient transport. Low rates of net carbon removal in the restored stream arose from high light availability resulting in high primary production, combined with low fine sediment availability restricting respiration. Thus, while restoration may have been effective for stream stabilization, it has decreased the functionality of the stream for net carbon removal to the atmosphere. Surprisingly, streambed potential respiration rates were indistinguishable between different geomorphic zones within the streams, suggesting that large-scale factors (i.e., nutrient and fine sediment supply) were more dominant controls than geomorphically controlled local variability.

Response of the soil microbial community and soil nutrient bioavailability to biomass harvesting and reserve tree retention in northern Minnesota aspen-dominated forests

Treesearch

Tera E. Lewandowski; Jodi A. Forrester; David J. Mladenoff; Anthony W. D' Amato; Brian J. Palik

2016-01-01

Intensive forest biomass harvesting, or the removal of harvesting slash (woody debris from tree branches and tops) for use as biofuel, has the potential to negatively affect the soil microbial community (SMC) due to loss of carbon and nutrient inputs from the slash, alteration of the soil microclimate, and increased nutrient leaching. These effects could result in...

Long-term performance evaluation of EBPR process in tropical climate: start-up, process stability, and the effect of operational pH and influent C:P ratio.

PubMed

Ong, Y H; Chua, A S M; Lee, B P; Ngoh, G C

2013-01-01

To date, little information is known about the operation of the enhanced biological phosphorus removal (EBPR) process in tropical climates. Along with the global concerns on nutrient pollution and the increasing array of local regulatory requirements, the applicability and compliance accountability of the EBPR process for sewage treatment in tropical climates is being evaluated. A sequencing batch reactor (SBR) inoculated with seed sludge from a conventional activated sludge (CAS) process was successfully acclimatized to EBPR conditions at 28 °C after 13 days' operation. Enrichment of Candidatus Accumulibacter phosphatis in the SBR was confirmed through fluorescence in situ hybridization (FISH). The effects of operational pH and influent C:P ratio on EBPR were then investigated. At pH 7 or pH 8, phosphorus removal rates of the EBPR processes were relatively higher when operated at C:P ratio of 3 than C:P ratio of 10, with 0.019-0.020 and 0.011-0.012 g-P/g-MLVSS•day respectively. One-year operation of the 28 °C EBPR process at C:P ratio of 3 and pH 8 demonstrated stable phosphorus removal rate of 0.020 ± 0.003 g-P/g-MLVSS•day, corresponding to effluent with phosphorus concentration <0.5 mg/L. This study provides the first evidence on good EBPR activity at relatively high temperature, indicating its applicability in a tropical climate.

Maize (Zea mays L) cultivars nutrients concentration in leaves and stalks

USDA-ARS?s Scientific Manuscript database

There is pressure for crop residue removal for use as biofuel, animal feed, animal bedding and many other functions which may increase nutrient export. However, there is little information about nutritional composition of maize stover considering the wide variability of cultivars used. The aim of th...

Carbohydrate and nutrient composition of corn stover from three Southeastern USA locations

USDA-ARS?s Scientific Manuscript database

Corn (Zea mays L.) stover has been identified as an important feedstock for bioenergy and bio-product production. Our objective was to quantify nutrient removal, carbohydrate composition, theoretical ethanol yield (TEY) for various stover fractions. In 2009, 2010, and 2011, whole-plant samples were ...

Nutrient leaching when compost is part of plant growth media

USDA-ARS?s Scientific Manuscript database

Bioretention cells collect urban runoff and are used to slow storm water surge, reduce or remove nutrients or other pollutants, and provide aesthetics to the landscape. A cell is filled with soil mixed with sand, compost, and other materials, and underlain by an aggregate layer and drainage pipe. Th...

Plant Leachate Nutrient Recovery with Biological, Thermal, and Photocatalytic Pretreatments

NASA Technical Reports Server (NTRS)

Wong, Les

2015-01-01

Plants are ideal for long term space travel: provide essential resources - oxygen, water, food; Water-soaked plants expel soluble nutrients in a leachate solution - toxins and wastes are also expelled and inhibit growth; biological, thermal, photocatalytic coupled with an acid digestion treatment will hopefully maximize recovery and remove wastes

Removal of nutrients and veterinary antibiotics from swine wastewater by a constructed macrophyte floating bed system.

PubMed

Xian, Qiming; Hu, Lixia; Chen, Hancheng; Chang, Zhizhou; Zou, Huixian

2010-12-01

The potential of three varieties of Italian ryegrass (Lolium multiflorum Lam.), Dryan, Tachimasari and Waseyutaka, to improve the water quality of swine wastewater was evaluated using a constructed macrophyte floating bed system. With respect to reductions in levels of nutrients, chemical oxygen demand (COD), and sulfonamide antimicrobials (SAs, including sulfadiazine, sulfamethazine, and sulfamethoxazole), Dryan performed better than Tachimasari and Waseyutaka. For Dryan, total N was reduced by 84.0%, total P by 90.4%, COD by 83.4% and sulfonamide antimicrobials by 91.8-99.5%. Similar results were observed for Tachimasari and Waseyutaka. The results indicated that the treatment of swine wastewater using the constructed macrophyte floating bed system was effective in the removal of nutrients and veterinary antibiotics. Copyright © 2010 Elsevier Ltd. All rights reserved.

[Effect of pilot UASB-SFSBR-MAP process for the large scale swine wastewater treatment].

PubMed

Wang, Liang; Chen, Chong-Jun; Chen, Ying-Xu; Wu, Wei-Xiang

2013-03-01

In this paper, a treatment process consisted of UASB, step-fed sequencing batch reactor (SFSBR) and magnesium ammonium phosphate precipitation reactor (MAP) was built to treat the large scale swine wastewater, which aimed at overcoming drawbacks of conventional anaerobic-aerobic treatment process and SBR treatment process, such as the low denitrification efficiency, high operating costs and high nutrient losses and so on. Based on the treatment process, a pilot engineering was constructed. It was concluded from the experiment results that the removal efficiency of COD, NH4(+) -N and TP reached 95.1%, 92.7% and 88.8%, the recovery rate of NH4(+) -N and TP by MAP process reached 23.9% and 83.8%, the effluent quality was superior to the discharge standard of pollutants for livestock and poultry breeding (GB 18596-2001), mass concentration of COD, TN, NH4(+) -N, TP and SS were not higher than 135, 116, 43, 7.3 and 50 mg x L(-1) respectively. The process developed was reliable, kept self-balance of carbon source and alkalinity, reached high nutrient recovery efficiency. And the operating cost was equal to that of the traditional anaerobic-aerobic treatment process. So the treatment process could provide a high value of application and dissemination and be fit for the treatment pf the large scale swine wastewater in China.

Plant functional types do not predict biomass responses to removal and fertilization in Alaskan tussock tundra

PubMed Central

Bret-Harte, M Syndonia; Mack, Michelle C; Goldsmith, Gregory R; Sloan, Daniel B; DeMarco, Jennie; Shaver, Gaius R; Ray, Peter M; Biesinger, Zy; Chapin, F Stuart

2008-01-01

Plant communities in natural ecosystems are changing and species are being lost due to anthropogenic impacts including global warming and increasing nitrogen (N) deposition. We removed dominant species, combinations of species and entire functional types from Alaskan tussock tundra, in the presence and absence of fertilization, to examine the effects of non-random species loss on plant interactions and ecosystem functioning. After 6 years, growth of remaining species had compensated for biomass loss due to removal in all treatments except the combined removal of moss, Betula nana and Ledum palustre (MBL), which removed the most biomass. Total vascular plant production returned to control levels in all removal treatments, including MBL. Inorganic soil nutrient availability, as indexed by resins, returned to control levels in all unfertilized removal treatments, except MBL. Although biomass compensation occurred, the species that provided most of the compensating biomass in any given treatment were not from the same functional type (growth form) as the removed species. This provides empirical evidence that functional types based on effect traits are not the same as functional types based on response to perturbation. Calculations based on redistributing N from the removed species to the remaining species suggested that dominant species from other functional types contributed most of the compensatory biomass. Fertilization did not increase total plant community biomass, because increases in graminoid and deciduous shrub biomass were offset by decreases in evergreen shrub, moss and lichen biomass. Fertilization greatly increased inorganic soil nutrient availability. In fertilized removal treatments, deciduous shrubs and graminoids grew more than expected based on their performance in the fertilized intact community, while evergreen shrubs, mosses and lichens all grew less than expected. Deciduous shrubs performed better than graminoids when B. nana was present, but not when it had been removed. Synthesis. Terrestrial ecosystem response to warmer temperatures and greater nutrient availability in the Arctic may result in vegetative stable-states dominated by either deciduous shrubs or graminoids. The current relative abundance of these dominant growth forms may serve as a predictor for future vegetation composition. PMID:18784797

Phosphate removal by refined aspen wood fiber treated with carboxymethyl cellulose and ferrous chloride

Treesearch

Thomas L. Eberhardt; Soo-Hong Min; James S. Han

2006-01-01

Biomass-based filtration media are of interest as an economical means to remove pollutants and nutrients found in stormwater runoff. Refined aspen wood fiber samples treated with iron salt solutions demonstrated limited capacities to remove (ortho)phosphate from test solutions. To provide additional sites for iron complex formation, and thereby impart a greater...

Interactions among irradiance, nutrients, and herbivores constrain a stream algal community.

PubMed

Rosemond, A D

1993-07-01

Using stream-side, flow-through channels, I tested for the effects of nutrients (NU) (nitrogen plus phosphorus), irradiance (L), and snail grazing (G) on a benthic algal community in a small, forested stream. Grazed communities were-dominated by a chlorophyte (basal cells ofStigeoclonium) and a cyanophyte (Chamaesiphon investiens), whereas ungrazed communities were comprised almost entirely of diatoms, regardless of nutrient and light levels. Snails maintained low algal biomass in all grazed treatments, presumably by consuming increased algal production in treatments to which L and NU were increased. When nutrients were increased, cellular nutrient content increased under ambient conditions (shaded, grazed) and biomass and productivity increased when snails were removed and light was increased. Together, nutrients and light had positive effects and grazing had negative effects on biomass (chlorophylla, AFDM, algal biovolume) and chlorophyll-and areal-specific productivity in ANOVAs. However, in most cases, only means from treatments in which all three factors were manipulated (ungrazed, +NU&L treatments) were significantly different from controls; effects of single factors were generally undetectable. These results indicate that all three factors simultaneously limited algal biomass and productivity in this stream during the summer months. Additionally, the effects of these factors in combination were in some cases different from the effects of single factors. For example, light had slight negative effects on some biomass parameters when added at ambient snail densities and nutrient concentrations, but had strong positive effects in conjunction with nutrient addition and snail removal. This study demonstrates that algal biomass and productivity can be under multiple constraints by irradiance, nutrients, and herbivores and indicates the need to employ multifactor experiments to test for such interactive effects.

Development of complementary feeding recommendations for 12-23-month-old children from low and middle socio-economic status in West Java, Indonesia: contribution of fortified foods towards meeting the nutrient requirement.

PubMed

Fahmida, Umi; Santika, Otte

2016-07-01

Inadequate nutrient intake as part of a complementary feeding diet is attributable to poor feeding practices and poor access to nutritious foods. Household socio-economic situation (SES) has an influence on food expenditure and access to locally available, nutrient-dense foods and fortified foods. This study aimed to develop and compare complementary feeding recommendations (CFR) for 12-23-month-old children in different SES and evaluate the contribution of fortified foods in meeting nutrient requirements. A cross-sectional survey was conducted in low and medium SES households (n 114/group) in urban Bandung district, West Java province, Indonesia. Food pattern, portion size and affordability were assessed, and CFR were developed for the low SES (LSES) and middle SES (MSES) using a linear programming (LP) approach; two models - with and without fortified foods - were run using LP, and the contribution of fortified foods in the final CFR was identified. Milk products, fortified biscuits and manufactured infant cereals were the most locally available and consumed fortified foods in the market. With the inclusion of fortified foods, problem nutrients were thiamin in LSES and folate and thiamin in MSES groups. Without fortified foods, more problem nutrients were identified in LSES, that is, Ca, Fe, Zn, niacin and thiamin. As MSES consumed more fortified foods, removing fortified foods was not possible, because most of the micronutrient-dense foods were removed from their food basket. There were comparable nutrient adequacy and problem nutrients between LSES and MSES when fortified foods were included. Exclusion of fortified foods in LSES was associated with more problem nutrients in the complementary feeding diet.

Nutrient Mitigation Efficiency in Agricultural Drainage Ditches: An Influence of Landscape Management.

PubMed

Iseyemi, Oluwayinka O; Farris, Jerry L; Moore, Matthew T; Choi, Seo-Eun

2016-06-01

Drainage systems are integral parts of agricultural landscapes and have the ability to intercept nutrient loading from runoff to surface water. This study investigated nutrient removal efficiency within replicated experimental agricultural drainage ditches during a simulated summer runoff event. Study objectives were to examine the influence of routine mowing of vegetated ditches on nutrient mitigation and to assess spatial transformation of nutrients along ditch length. Both mowed and unmowed ditch treatments decreased NO3 (-)-N by 79 % and 94 % and PO4 (3-) by 95 % and 98 %, respectively, with no significant difference in reduction capacities between the two treatments. This suggests occasional ditch mowing as a management practice would not undermine nutrient mitigation capacity of vegetated drainage ditches.

Development of anaerobic ammonium oxidation (anammox) for biological nitrogen removal in domestic wastewater treatment (Case study: Surabaya City, Indonesia)

NASA Astrophysics Data System (ADS)

Wijaya, I. Made Wahyu; Soedjono, Eddy Setiadi; Fitriani, Nurina

2017-11-01

Domestic wastewater effluent is the main contributor to diverse water pollution problems. The contaminants contained in the wastewater lead the low quality of water. The presence of ammonium and nitrate along with phosphorus are potentially cause eutrophication and endanger aquatic life. Excess nutrients, mostly N and P is the main cause of eutrophication which is result in oxygen depletion, biodiversity reduction, fish kills, odor and increased toxicity. Most of the domestic wastewater in Surabaya City still contains nitrogen that exceeded the threshold. The range of ammonium and orthophosphate concentration in the domestic wastewater is between 6.29 mg/L - 38.91 mg/L and 0.44 mg/L - 1.86 mg/L, respectively. An advance biological nitrogen removal process called anammox is a sustainable and cost effective alternative to the basic method of nitrogen removal, such as nitrification and denitrification. Many research have been conducted through anammox and resulted promisingly way to remove nitrogen. In this process, ammonium will be oxidized with nitrite as an electron acceptor to produce nitrogen gas and low nitrate in anoxic condition. Anammox requires less oxygen demand, no needs external carbon source, and low operational cost. Based on its advantages, anammox is possible to apply in domestic wastewater treatment in Surabaya with many further studies.

Comparative study on nutrient removal of agricultural non-point source pollution for three filter media filling schemes in eco-soil reactors.

PubMed

Du, Fuyi; Xie, Qingjie; Fang, Longxiang; Su, Hang

2016-08-01

Nutrients (nitrogen and phosphorus) from agricultural non-point source (NPS) pollution have been increasingly recognized as a major contributor to the deterioration of water quality in recent years. The purpose of this article is to investigate the discrepancies in interception of nutrients in agricultural NPS pollution for eco-soil reactors using different filling schemes. Parallel eco-soil reactors of laboratory scale were created and filled with filter media, such as grit, zeolite, limestone, and gravel. Three filling schemes were adopted: increasing-sized filling (I-filling), decreasing-sized filling (D-filling), and blend-sized filling (B-filling). The systems were intermittent operations via simulated rainstorm runoff. The nutrient removal efficiency, biomass accumulation and vertical dissolved oxygen (DO) distribution were defined to assess the performance of eco-soil. The results showed that B-filling reactor presented an ideal DO for partial nitrification-denitrification across the eco-soil, and B-filling was the most stable in the change of bio-film accumulation trends with depth in the three fillings. Simultaneous and highest removals of NH4(+)-N (57.74-70.52%), total nitrogen (43.69-54.50%), and total phosphorus (42.50-55.00%) were obtained in the B-filling, demonstrating the efficiency of the blend filling schemes of eco-soil for oxygen transfer and biomass accumulation to cope with agricultural NPS pollution.

Fate of Nutrients in Shallow Groundwater Receiving Treated Septage, Malibu, CA

PubMed Central

Izbicki, John A

2014-01-01

Treated wastewater discharged from more than 400 onsite wastewater treatment systems (OWTS) near the Civic Center area of Malibu, California, 40 km west of downtown Los Angeles, composes 28% of the recharge to a 3.4 km2 alluvial aquifer. On the basis of δ18O and δD data, the fraction of wastewater in some samples was >70%. Ammonium and nitrate concentrations in water from 15 water-table wells sampled in July 2009 and April 2010 ranged from <0.01 to 12 milligrams per liter as nitrogen (mg/L as N), and from <0.01 to 11 mg/L as N, respectively. Chemical and isotopic data (δ15N of ammonium and nitrate, and δ18O of nitrate) show two processes remove nitrogen discharged from OWTS. Where groundwater was reducing, sorption of ammonium resulted in 30 to 50% nitrogen removal. Where groundwater was initially oxic, nitrification with subsequent denitrification as reducing conditions developed, resulted in up to 60% nitrogen removal. Nitrogen removal through sorption dominated during the cooler April sample period, and denitrification dominated during the warmer July sample period. The combination of mixing and nitrogen removal due to denitrification, sorption, and volatilization produces a δ15N apparent fractionation factor (εapp = −5), that can be explained using laboratory-derived fractionation factors (ε) for the individual processes. Phosphate concentrations ranged from < 0.04 to 2 mg/L as phosphorous. Sorption to iron oxides on the surfaces of mineral grains at near-neutral pH's removed some phosphate; however, little removal occurred at more alkaline pH's (>7.3). PMID:24902718

Fate of nutrients in shallow groundwater receiving treated septage, Malibu, CA

USGS Publications Warehouse

Izbicki, John

2014-01-01

Treated wastewater discharged from more than 400 onsite wastewater treatment systems (OWTS) near the Civic Center area of Malibu, California, 40 km west of downtown Los Angeles, composes 28% of the recharge to a 3.4 km2 alluvial aquifer. On the basis of δ18O and δD data, the fraction of wastewater in some samples was >70%. Ammonium and nitrate concentrations in water from 15 water-table wells sampled in July 2009 and April 2010 ranged from <0.01 to 12 milligrams per liter as nitrogen (mg/L as N), and from <0.01 to 11 mg/L as N, respectively. Chemical and isotopic data (δ15N of ammonium and nitrate, and δ18O of nitrate) show two processes remove nitrogen discharged from OWTS. Where groundwater was reducing, sorption of ammonium resulted in 30 to 50% nitrogen removal. Where groundwater was initially oxic, nitrification with subsequent denitrification as reducing conditions developed, resulted in up to 60% nitrogen removal. Nitrogen removal through sorption dominated during the cooler April sample period, and denitrification dominated during the warmer July sample period. The combination of mixing and nitrogen removal due to denitrification, sorption, and volatilization produces a δ15N apparent fractionation factor (εapp= -5), that can be explained using laboratory-derived fractionation factors (ε) for the individual processes. Phosphate concentrations ranged from <0.04 to 2 mg/L as phosphorous. Sorption to iron oxides on the surfaces of mineral grains at near-neutral pH's removed some phosphate; however, little removal occurred at more alkaline pH's (>7.3).

Assessing Chemical Retention Process Controls in Ponds

NASA Astrophysics Data System (ADS)

Torgersen, T.; Branco, B.; John, B.

2002-05-01

Small ponds are a ubiquitous component of the landscape and have earned a reputation as effective chemical retention devices. The most common characterization of pond chemical retention is the retention coefficient, Ri= ([Ci]inflow-[Ci] outflow)/[Ci]inflow. However, this parameter varies widely in one pond with time and among ponds. We have re-evaluated literature reported (Borden et al., 1998) monthly average retention coefficients for two ponds in North Carolina. Employing a simple first order model that includes water residence time, the first order process responsible for species removal have been separated from the water residence time over which it acts. Assuming the rate constant for species removal is constant within the pond (arguable at least), the annual average rate constant for species removal is generated. Using the annual mean rate constant for species removal and monthly water residence times results in a significantly enhanced predictive capability for Davis Pond during most months of the year. Predictive ability remains poor in Davis Pond during winter/unstratified periods when internal loading of P and N results in low to negative chemical retention. Predictive ability for Piedmont Pond (which has numerous negative chemical retention periods) is improved but not to the same extent as Davis Pond. In Davis Pond, the rate constant for sediment removal (each month) is faster than the rate constant for water and explains the good predictability for sediment retention. However, the removal rate constant for P and N is slower than the removal rate constant for sediment (longer water column residence time for P,N than for sediment). Thus sedimentation is not an overall control on nutrient retention. Additionally, the removal rate constant for P is slower than for TOC (TOC is not the dominate removal process for P) and N is removed slower than P (different in pond controls). For Piedmont Pond, sediment removal rate constants are slower than the removal rate constant for water indicating significant sediment resuspension episodes. It appears that these sediment resuspension events are aperiodic and control the loading and the chemical retention capability of Piedmont Pond for N,P,TOC. These calculated rate constants reflect the differing internal loading processes for each component and suggest means and mechanisms for the use of ponds in water quality management.

Geoengineering, marine microalgae, and climate stabilization in the 21st century

NASA Astrophysics Data System (ADS)

Greene, Charles H.; Huntley, Mark E.; Archibald, Ian; Gerber, Léda N.; Sills, Deborah L.; Granados, Joe; Beal, Colin M.; Walsh, Michael J.

2017-03-01

Society has set ambitious targets for stabilizing mean global temperature. To attain these targets, it will have to reduce CO2 emissions to near zero by mid-century and subsequently remove CO2 from the atmosphere during the latter half of the century. There is a recognized need to develop technologies for CO2 removal; however, attempts to develop direct air-capture systems have faced both energetic and financial constraints. Recently, BioEnergy with Carbon Capture and Storage (BECCS) has emerged as a leading candidate for removing CO2 from the atmosphere. However, BECCS can have negative consequences on land, nutrient, and water use as well as biodiversity and food production. Here, we describe an alternative approach based on the large-scale industrial production of marine microalgae. When cultivated with proper attention to power, carbon, and nutrient sources, microalgae can be processed to produce a variety of biopetroleum products, including carbon-neutral biofuels for the transportation sector and long-lived, potentially carbon-negative construction materials for the built environment. In addition to these direct roles in mitigating and potentially reversing the effects of fossil CO2 emissions, microalgae can also play an important indirect role. As microalgae exhibit much higher primary production rates than terrestrial plants, they require much less land area to produce an equivalent amount of bioenergy and/or food. On a global scale, the avoided emissions resulting from displacement of conventional agriculture may exceed the benefits of microalgae biofuels in achieving the climate stabilization goals.

Biotite weathering in a natural forest setting near Derome, Sweden

NASA Astrophysics Data System (ADS)

Balogh-Brunstad, Z.; Negrich, K.; Hassenkam, T.; Wallander, H.; Stipp, S. L.

2011-12-01

Chemical weathering is a key process in non-nitrogen nutrient acquisition by microbes, fungi and plants. Biotite is commonly the major source of potassium, magnesium and iron. A unique opportunity arose to study natural weathering of biotite by mixed conifer and hardwood forest vegetation and associated microbes and fungi at an abandoned mine site. After the mining stopped over 30 years ago biotite was left behind in piles and the forest vegetation progressively colonized the site. Samples were collected from the top 40 cm of the biotite piles in a vicinity of pine, spruce and birch trees and included some young seedlings. Macroscopic observations documented abundant hyphal growth between the sheets of biotite. We hypothesized that fungal hyphae grow between the sheets to explore the nutrient source and weather the biotite leaving hyphal-sized etched channels on the basal surfaces. Biotite surfaces were examined with atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM) in their natural state and after removing the biological material from the mineral surfaces. The ESEM images show extensive hyphal colonization and patchy biofilm cover of the entire biotite surface on and within the sheets and at the edges of the particles. Fungal hyphae did not attach strongly to the basal surfaces of the biotite flakes as a result of small particles on the surfaces and the uneven micro-topography. The AFM images illustrate a complex microbial community around the fungal hyphae and detailed fungal morphology. High resolution AFM images show unique globular features of diameter 10-100 nm on all biofilm surfaces. However, removal of the biological material resulted in smooth and un-etched surfaces indicating that either our removal techniques are too invasive and destroy the surface layers of interest, or the etching of the basal surface is not the main mechanism for chemical weathering and base-cation nutrient immobilization in this natural setting. Species-specific interactions at the biofilm-microbe-fungus-mineral interface and spatial distribution in the biotite pile are under further investigation.

Solute-specific scaling of inorganic nitrogen and phosphorus uptake in streams

NASA Astrophysics Data System (ADS)

Hall, R. O., Jr.; Baker, M. A.; Rosi-Marshall, E. J.; Tank, J. L.; Newbold, J. D.

2013-11-01

Stream ecosystem processes such as nutrient cycling may vary with stream position in the network. Using a scaling approach, we examined the relationship between stream size and nutrient uptake length, which represents the mean distance that a dissolved solute travels prior to removal from the water column. Ammonium (NH4+) uptake length increased proportionally with stream size measured as specific discharge (discharge/stream width) with a scaling exponent = 1.01. In contrast, uptake lengths for nitrate (NO3-) and soluble reactive phosphorus (SRP) increased more rapidly than increases in specific discharge (scaling exponents = 1.19 for NO3- and 1.35 for SRP). Additionally, the ratio of inorganic nitrogen (N) uptake length to SRP uptake length declined with stream size; there was relatively lower demand for SRP compared to N as stream size increased. Finally, we related the scaling of uptake length with specific discharge to that of stream length using Hack's law and downstream hydraulic geometry. Ammonium uptake length increased less than proportionally with distance from the headwaters, suggesting a strong role for larger streams and rivers in regulating nutrient transport.

Impact of seasonality on the nutrient concentrations in Gautami-Godavari Estuarine Mangrove Complex, Andhra Pradesh, India.

PubMed

Rao, Karuna; Priya, Namrata; Ramanathan, A L

2018-04-01

Spatiotemporal variations of dissolved nutrients were studied along Gautami-Godavari mangrove ecosystem to delineate their sources and fate. Average values of nitrate (NO 3 - ), dissolved silica (DSi) and phosphate (PO 4 3- ) is 2.09 mg/l, 12.7 mg/l and 0.16 mg/l in wet season and 0.47 mg/l, 6.96 mg/l and 0.29 mg/l in dry season respectively. In wet season river discharge has significant influence on NO 3 - and DSi. In dry season, NO 3 - and PO 4 3- are controlled by groundwater discharge, benthic exchange and various in situ processes owing to sediment redox condition. Mixing model shows net addition of phosphate in Coringa mangroves (95%) and Lower estuary (13%) and net removal of nitrate (24.79%) in Coringa mangrove and in estuary (58.9%). Thus present mangrove acts as net source for phosphate and net sink for nitrate and DSi. Nutrient ratio shows seasonal switching between potential Phosphorus and Nitrogen limitation in wet and dry season respectively. Copyright © 2018 Elsevier Ltd. All rights reserved.

Proline Precursors and Collagen Synthesis: Biochemical Challenges of Nutrient Supplementation and Wound Healing.

PubMed

Albaugh, Vance L; Mukherjee, Kaushik; Barbul, Adrian

2017-11-01

Wound healing is a complex process marked by highly coordinated immune fluxes into an area of tissue injury; these are required for re-establishment of normal tissue integrity. Along with this cascade of cellular players, wound healing also requires coordinated flux through a number of biochemical pathways, leading to synthesis of collagen and recycling or removal of damaged tissues. The availability of nutrients, especially amino acids, is critical for wound healing, and enteral supplementation has been intensely studied as a potential mechanism to augment wound healing-either by increasing tensile strength, decreasing healing time, or both. From a practical standpoint, although enteral nutrient supplementation may seem like a reasonable strategy to augment healing, a number of biochemical and physiologic barriers exist that limit this strategy. In this critical review, the physiology of enteral amino acid metabolism and supplementation and challenges therein are discussed in the context of splanchnic physiology and biochemistry. Additionally, a review of studies examining various methods of amino acid supplementation and the associated effects on wound outcomes are discussed. © 2017 American Society for Nutrition.

Removal of trace organic chemicals and performance of a novel hybrid ultrafiltration-osmotic membrane bioreactor.

PubMed

Holloway, Ryan W; Regnery, Julia; Nghiem, Long D; Cath, Tzahi Y

2014-09-16

A hybrid ultrafiltration-osmotic membrane bioreactor (UFO-MBR) was investigated for over 35 days for nutrient and trace organic chemical (TOrC) removal from municipal wastewater. The UFO-MBR system uses both ultrafiltration (UF) and forward osmosis (FO) membranes in parallel to simultaneously extract clean water from an activated sludge reactor for nonpotable (or environmental discharge) and potable reuse, respectively. In the FO stream, water is drawn by osmosis from activated sludge through an FO membrane into a draw solution (DS), which becomes diluted during the process. A reverse osmosis (RO) system is then used to reconcentrate the diluted DS and produce clean water suitable for direct potable reuse. The UF membrane extracts water, dissolved salts, and some nutrients from the system to prevent their accumulation in the activated sludge of the osmotic MBR. The UF permeate can be used for nonpotable reuse purposes (e.g., irrigation and toilet flushing). Results from UFO-MBR investigation illustrated that the chemical oxygen demand, total nitrogen, and total phosphorus removals were greater than 99%, 82%, and 99%, respectively. Twenty TOrCs were detected in the municipal wastewater that was used as feed to the UFO-MBR system. Among these 20 TOrCs, 15 were removed by the hybrid UFO-MBR system to below the detection limit. High FO membrane rejection was observed for all ionic and nonionic hydrophilic TOrCs and lower rejection was observed for nonionic hydrophobic TOrCs. With the exceptions of bisphenol A and DEET, all TOrCs that were detected in the DS were well rejected by the RO membrane. Overall, the UFO-MBR can operate sustainably and has the potential to be utilized for direct potable reuse applications.

Design of a Nutrient Reclamation System for the Cultivation of Microalgae for Biofuel Production and Other Industrial Applications

NASA Astrophysics Data System (ADS)

Sandefur, Heather Nicole

Microalgal biomass has been identified as a promising feedstock for a number of industrial applications, including the synthesis of new pharmaceutical and biofuel products. However, there are several economic limitations associated with the scale up of existing algal production processes. Critical economic studies of algae-based industrial processes highlight the high cost of supplying essential nutrients to microalgae cultures. With microalgae cells having relatively high nitrogen contents (4 to 8%), the N fertilizer cost in industrial-scale production is significant. In addition, the disposal of the large volumes of cell residuals that are generated during product extraction stages can pose other economic challenges. While waste streams can provide a concentrated source of nutrients, concerns about the presence of biological contaminants and the expense of heat treatment pose challenges to processes that use wastewater as a nutrient source in microalgae cultures. The goal of this study was to evaluate the potential application of ultrafiltration technology to aid in the utilization of agricultural wastewater in the cultivation of a high-value microalgae strain. An ultrafiltration system was used to remove inorganic solids and biological contaminants from wastewater taken from a swine farm in Savoy, Arkansas. The permeate from the system was then used as the nutrient source for the cultivation of the marine microalgae Porphyridium cruentum. During the ultrafiltration system operation, little membrane fouling was observed, and permeate fluxes remained relatively constant during both short-term and long-term tests. The complete rejection of E. coli and coliforms from the wastewater was also observed, in addition to a 75% reduction in total solids, including inorganic materials. The processed permeate was shown to have very high concentrations of total nitrogen (695.6 mg L-1) and total phosphorus (69.1 mg L-1 ). In addition, the growth of P. cruentum was analyzed in a medium containing swine waste permeate, and was compared to P. cruentum growth in a control medium. A higher biomass productivity, lipid productivity, and lipid content were observed in the microalgae cultivated in the swine waste medium compared to that of the control medium. These results suggest that, through the use of ultrafiltration technology as an alternative to traditional heat treatment, agricultural wastewaters could be effectively utilized as a nutrient source for microalgae cultivation.

Coastal eutrophication as a driver of salt marsh loss.

PubMed

Deegan, Linda A; Johnson, David Samuel; Warren, R Scott; Peterson, Bruce J; Fleeger, John W; Fagherazzi, Sergio; Wollheim, Wilfred M

2012-10-18

Salt marshes are highly productive coastal wetlands that provide important ecosystem services such as storm protection for coastal cities, nutrient removal and carbon sequestration. Despite protective measures, however, worldwide losses of these ecosystems have accelerated in recent decades. Here we present data from a nine-year whole-ecosystem nutrient-enrichment experiment. Our study demonstrates that nutrient enrichment, a global problem for coastal ecosystems, can be a driver of salt marsh loss. We show that nutrient levels commonly associated with coastal eutrophication increased above-ground leaf biomass, decreased the dense, below-ground biomass of bank-stabilizing roots, and increased microbial decomposition of organic matter. Alterations in these key ecosystem properties reduced geomorphic stability, resulting in creek-bank collapse with significant areas of creek-bank marsh converted to unvegetated mud. This pattern of marsh loss parallels observations for anthropogenically nutrient-enriched marshes worldwide, with creek-edge and bay-edge marsh evolving into mudflats and wider creeks. Our work suggests that current nutrient loading rates to many coastal ecosystems have overwhelmed the capacity of marshes to remove nitrogen without deleterious effects. Projected increases in nitrogen flux to the coast, related to increased fertilizer use required to feed an expanding human population, may rapidly result in a coastal landscape with less marsh, which would reduce the capacity of coastal regions to provide important ecological and economic services.

Global riverine N and P transport to ocean increased during the 20th century despite increased retention along the aquatic continuum

NASA Astrophysics Data System (ADS)

Beusen, Arthur H. W.; Bouwman, Alexander F.; Van Beek, Ludovicus P. H.; Mogollón, José M.; Middelburg, Jack J.

2016-04-01

Various human activities - including agriculture, water consumption, river damming, and aquaculture - have intensified over the last century. This has had a major impact on nitrogen (N) and phosphorus (P) cycling in global continental waters. In this study, we use a coupled nutrient-input-hydrology-in-stream nutrient retention model to quantitatively track the changes in the global freshwater N and P cycles over the 20th century. Our results suggest that, during this period, the global nutrient delivery to streams increased from 34 to 64 Tg N yr-1 and from 5 to 9 Tg P yr-1. Furthermore, in-stream retention and removal grew from 14 to 27 Tg N yr-1 and 3 to 5 Tg P yr-1. One of the major causes of increased retention is the growing number of reservoirs, which now account for 24 and 22 % of global N and P retention/removal in freshwater systems, respectively. This increase in nutrient retention could not balance the increase in nutrient delivery to rivers with the consequence that river nutrient transport to the ocean increased from 19 to 37 Tg N yr-1 and from 2 to 4 Tg P yr-1. Human activities have also led to a global increase in the molar N : P ratio in freshwater bodies.

Global riverine N and P transport to ocean increased during the twentieth century despite increased retention along the aquatic continuum

NASA Astrophysics Data System (ADS)

Beusen, A. H. W.; Bouwman, A. F.; Van Beek, L. P. H.; Mogollón, J. M.; Middelburg, J. J.

2015-12-01

Various human activities, including agriculture, water consumption, river damming, and aquaculture, have intensified over the last century. This has had a major impact on nitrogen (N) and phosphorus (P) cycling in global continental waters. In this study, we use a coupled nutrient-input, hydrology, in-stream nutrient retention model to quantitatively track the changes in the global freshwater N and P cycles over the 20th century. Our results suggest that, during this period, the global nutrient delivery to streams increased from 34 to 64 Tg N yr-1 and from 5 to 9 Tg N yr-1. Furthermore, in-stream retention and removal grew from 14 to 27 Tg N yr-1 and 3 to 5 Tg N yr-1. One of the major cause of increased retention is the growing number of reservoirs which now account for 24 and 22 % of global N and P retention/removal in freshwater systems, respectively. This increase in nutrient retention could not balance the increase in nutrient delivery to rivers with the consequence that river nutrient transport to the ocean increased from 19 to 37 Tg N yr-1 and from 2 to 4 Tg N yr-1. Human activities have also led to a global increase in the molar N : P ratio in freshwater bodies.

Sequential Sedimentation-Biofiltration System for the purification of a small urban river (the Sokolowka, Lodz) supplied by stormwater.

PubMed

Szklarek, S; Wagner, I; Jurczak, T; Zalewski, M

2018-01-01

The study analyses the efficiency of a Sequentional Sedimentation-Biofiltration System (SSBS) built on the Sokolowka river in Lodz (Poland). It was constructed to purify a small urban river whose hydrological regime is dominated by stormwater and meltwater. The SSBS was constructed on a limited area as multi-zone constructed wetlands. The SSBS consists of three zones: sedimentation zone with structures added to improve sedimentation, a geochemical barrier made of limestone deposit and biofiltration zone. The purification processes of total suspended solids (TSS), total phosphorus (TP), total nitrogen (TP) and other nutrients: phosphates (PO 4 3- ), ammonium (NH 4 + ) and nitrates (NO 3 - ) of the SSBS were analyzed. Chloride (Cl - ) reduction was investigated. Monitoring conducted in the first two hydrological years after construction indicated that the SSBS removed 61.4% of TSS, 37.3% of TP, 30.4% of PO 4 3- , 46.1% of TN, 2.8% of NH4+, 44.8% of NO 3 - and 64.0% of Cl - . The sedimentation zone played a key role in removing TSS and nutrients. The geochemical barrier and biofiltration zone each significantly improved overall efficiency by 4-10% for TSS, PO 4 3- , TN, NO 3 - and Cl - . Although the system reduced the concentration of chloride, further studies are needed to determine the circulation of Cl - in constructed wetlands (CWs), and to assess its impact on purification processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential and costs of carbon dioxide removal by enhanced weathering of rocks

NASA Astrophysics Data System (ADS)

Strefler, Jessica; Amann, Thorben; Bauer, Nico; Kriegler, Elmar; Hartmann, Jens

2018-03-01

The chemical weathering of rocks currently absorbs about 1.1 Gt CO2 a-1 being mainly stored as bicarbonate in the ocean. An enhancement of this slow natural process could remove substantial amounts of CO2 from the atmosphere, aiming to offset some unavoidable anthropogenic emissions in order to comply with the Paris Agreement, while at the same time it may decrease ocean acidification. We provide the first comprehensive assessment of economic costs, energy requirements, technical parameterization, and global and regional carbon removal potential. The crucial parameters defining this potential are the grain size and weathering rates. The main uncertainties about the potential relate to weathering rates and rock mass that can be integrated into the soil. The discussed results do not specifically address the enhancement of weathering through microbial processes, feedback of geogenic nutrient release, and bioturbation. We do not only assess dunite rock, predominantly bearing olivine (in the form of forsterite) as the mineral that has been previously proposed to be best suited for carbon removal, but focus also on basaltic rock to minimize potential negative side effects. Our results show that enhanced weathering is an option for carbon dioxide removal that could be competitive already at 60 US  t-1 CO2 removed for dunite, but only at 200 US  t-1 CO2 removed for basalt. The potential carbon removal on cropland areas could be as large as 95 Gt CO2 a-1 for dunite and 4.9 Gt CO2 a-1 for basalt. The best suited locations are warm and humid areas, particularly in India, Brazil, South-East Asia and China, where almost 75% of the global potential can be realized. This work presents a techno-economic assessment framework, which also allows for the incorporation of further processes.

Cost-performance analysis of nutrient removal in a full-scale oxidation ditch process based on kinetic modeling.

PubMed

Li, Zheng; Qi, Rong; Wang, Bo; Zou, Zhe; Wei, Guohong; Yang, Min

2013-01-01

A full-scale oxidation ditch process for treating sewage was simulated with the ASM2d model and optimized for minimal cost with acceptable performance in terms of ammonium and phosphorus removal. A unified index was introduced by integrating operational costs (aeration energy and sludge production) with effluent violations for performance evaluation. Scenario analysis showed that, in comparison with the baseline (all of the 9 aerators activated), the strategy of activating 5 aerators could save aeration energy significantly with an ammonium violation below 10%. Sludge discharge scenario analysis showed that a sludge discharge flow of 250-300 m3/day (solid retention time (SRT), 13-15 days) was appropriate for the enhancement of phosphorus removal without excessive sludge production. The proposed optimal control strategy was: activating 5 rotating disks operated with a mode of "111100100" ("1" represents activation and "0" represents inactivation) for aeration and sludge discharge flow of 200 m3/day (SRT, 19 days). Compared with the baseline, this strategy could achieve ammonium violation below 10% and TP violation below 30% with substantial reduction of aeration energy cost (46%) and minimal increment of sludge production (< 2%). This study provides a useful approach for the optimization of process operation and control.

Application of Moringa Oleifera seed extract to treat coffee fermentation wastewater.

PubMed

Garde, William K; Buchberger, Steven G; Wendell, David; Kupferle, Margaret J

2017-05-05

Wastewater generated from wet processing of coffee cherries degrades stream water quality downstream of processing mills and impacts human health. The widespread popularity of coffee as an export makes this a global problem, although the immediate impact is local. Approximately 40% of all coffee around the world is wet processed, producing wastewater rich in organic nutrients that can be hazardous to aquatic systems. Moringa Oleifera Seed Extract (MOSE) offers promise as a local and affordable "appropriate" coagulation technology for aiding in the treatment of coffee wastewater. Field research was conducted at the Kauai Coffee Company to investigate the application of MOSE to treat coffee fermentation wastewater (CFW). Coagulation tests were conducted at five pH CFW levels (3-7) and MOSE doses (0-4g/L). After settling, TSS, COD, nitrate, nitrite, total nitrogen, and pH of supernatant from each test were measured. MOSE reduced TSS, COD, nitrate, and nitrite in CFW to varying degrees dependent on pH and dose applied. TSS removal ranged from 8% to 54%. Insoluble COD removal ranged from 26% to 100% and total COD removal ranged from 1% to 25%. Nitrate and nitrite reduction ranged from 20% to 100%. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of physical and morphometric factors on nutrient removal properties in agricultural ponds.

PubMed

Saito, M; Onodera, S; Okubo, K; Takagi, S; Maruyama, Y; Jin, G; Shimizu, Y

2015-01-01

Effects of physical and morphometric factors on nutrient removal properties were studied in small agricultural ponds with different depths, volumes, and residence times in western Japan. Average residence time was estimated to be >15 days, and it tended to decrease from summer to winter because of the increase in water withdrawal for agricultural activity. Water temperature was clearly different between the surface and bottom layers; this indicates that thermal stratification occurred in summer. Chlorophyll-a was significantly high (>20 μg/L) in the surface layer (<0.5 m) and influenced by the thermal stratification. Removal ratios of dissolved total nitrogen (DTN) and dissolved total phosphorus in the ponds were estimated to be 53-98% and 39-98% in August and 10-92% and 36-57% in December, respectively. Residence time of the ponds was longer in August than in December, and DTN removal, in particular, was more significant in ponds with longer residence time. Our results suggest residence time is an important factor for nitrogen removal in small agricultural ponds as well as large lakes.

Simulating phosphorus removal from a vertical-flow constructed wetland grown with C alternifolius species

Treesearch

Ying Ouyang; Lihua Cui; Gary Feng; John Read

2015-01-01

Vertical flow constructed wetland (VFCW) is a promising technique for removal of excess nutrients and certain pollutants from wastewaters. The aim of this study was to develop a STELLA (structural thinking, experiential learning laboratory with animation) model for estimating phosphorus (P) removal in an artificial VFCW (i.e., a substrate column with six zones) grown...

Illustrated manual on composting for improved soil fertility and enhanced cocoa production

USDA-ARS?s Scientific Manuscript database

In West and Central Africa, most cocoa farms are old and the soils are highly depleted in major nutrients. Cocoa pod harvest continues to remove nutrients, and this loss of soil fertility is one of the major causes of low cocoa yields and subsequent economic losses. Plant pathogens, including nema...

Comparison of nutrient removal capacity and biomass settleability of four high-potential microalgal species.

PubMed

Su, Yanyan; Mennerich, Artur; Urban, Brigitte

2012-11-01

Four common used microalgae species were compared in terms of settleability, nutrient removal capacity and biomass productivity. After 1 month training, except cyanobacteria Phormidium sp., three green microalgae species, Chlamydomonas reinhardtii, Chlorella vulgaris and Scenedesmus rubescens, showed good settleability. The N and P removal efficiency was all above 99% within 7, 4, 6 and 6 days for N and 4, 2, 3 and 4 days for P, resulting in the N removal rates of 3.66±0.17, 6.39±0.20, 4.39±0.06 and 4.31±0.18 mg N/l/d and P removal rates of 0.56±0.07, 0.89±0.05, 0.76±0.09 and 0.60±0.05 mg P/l/d for Phormidium sp., C. reinhardtii, C. vulgaris and S. rubescens, respectively. Phormidium sp. had the lowest algal biomass productivity (2.71±0.7 g/m(2)/d) and the other three green microalgae showed higher algal biomass productivity (around 6 g/m(2)/d). Assimilation into biomass was the main removal mechanism for N and P. Copyright © 2012 Elsevier Ltd. All rights reserved.

Optimization of operation conditions for the startup of aerobic granular sludge reactors biologically removing carbon, nitrogen, and phosphorous.

PubMed

Lochmatter, Samuel; Holliger, Christof

2014-08-01

The transformation of conventional flocculent sludge to aerobic granular sludge (AGS) biologically removing carbon, nitrogen and phosphorus (COD, N, P) is still a main challenge in startup of AGS sequencing batch reactors (AGS-SBRs). On the one hand a rapid granulation is desired, on the other hand good biological nutrient removal capacities have to be maintained. So far, several operation parameters have been studied separately, which makes it difficult to compare their impacts. We investigated seven operation parameters in parallel by applying a Plackett-Burman experimental design approach with the aim to propose an optimized startup strategy. Five out of the seven tested parameters had a significant impact on the startup duration. The conditions identified to allow a rapid startup of AGS-SBRs with good nutrient removal performances were (i) alternation of high and low dissolved oxygen phases during aeration, (ii) a settling strategy avoiding too high biomass washout during the first weeks of reactor operation, (iii) adaptation of the contaminant load in the early stage of the startup in order to ensure that all soluble COD was consumed before the beginning of the aeration phase, (iv) a temperature of 20 °C, and (v) a neutral pH. Under such conditions, it took less than 30 days to produce granular sludge with high removal performances for COD, N, and P. A control run using this optimized startup strategy produced again AGS with good nutrient removal performances within four weeks and the system was stable during the additional operation period of more than 50 days. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biological nutrient removal with low nitrous oxide generation by cancelling the anaerobic phase and extending the idle phase in a sequencing batch reactor.

PubMed

Chen, Yinguang; Wang, Dongbo; Zheng, Xiong; Li, Xiang; Feng, Leiyu; Chen, Hong

2014-08-01

Although wastewater biological nutrient removal can be achieved by alternating the anaerobic-oxic-anoxic phases, significant amount of nitrous oxide (N2O) is generated in oxic phases, where ammonia-oxidizing bacteria (AOB) rather than heterotrophic denitrifiers are the main contributors. Here a new efficient strategy to remarkably reduce N2O generation was reported. It was found that by cancelling the anaerobic phase and extending the idle phase the N2O generation was reduced by 42% using synthetic wastewater, whereas the total nitrogen and phosphorus removals were unaffected. The mechanistic investigations revealed that the cancelling of anaerobic phase benefited heterotrophic denitrifiers instead of AOB to be responsible for nitrogen removal in the oxic phases, increased the ratio of total nitrogen removal driven by external carbon source, and decreased nitrite accumulation. Quantitative real-time polymerase chain reaction and fluorescence in situ hybridization analyses further showed that the new strategy increased the number of N2O reducing bacteria but decreased the abundance of glycogen accumulating organisms, with N2O as their primary denitrification product. It was also determined that the ratio of nitric oxide reductase activity to N2O reductase activity was significantly decreased after anaerobic phase was cancelled. All these observations were in accord with the reduction of N2O production. The feasibility of this strategy to minimize the generation of N2O was finally confirmed for a real municipal wastewater. The results reported in this paper provide a new viewpoint to reduce N2O generation from wastewater biological nutrient removal. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influences of seasons, N/P ratios and chemical compounds on phosphorus removal performance in algal pond combined with constructed wetlands.

PubMed

Zhimiao, Zhao; Xinshan, Song; Yanping, Xiao; Yufeng, Zhao; Zhijie, Gong; Fanda, Lin; Yi, Ding; Wei, Wang; Tianling, Qin

2016-12-15

Nitrogen (N) and phosphorous (P) are main contaminants and P removal was restrained by several factors: season, N/P, and chemical compounds (CCs) in water ecosystems. In this paper, two algal ponds combined with constructed wetlands were built to increase the removal performance. Different hydraulic retention time (HRT), different N/P and chemical compounds were chosen to investigate the influences of the above factors on the contaminant removal performance. The optimum phosphorus removal rate was 69.74% under the nitrogen removal of 92.85% in influent containing PO 4 3- after 3-day HRT in algal pond combined with constructed wetlands. The investigation results indicated that these factors improved the nutrient removal efficiencies. Seasonal influence on the removal performance can be avoided by choosing the optimal HRT length of 3days. The higher N/P at 60 can improve the phosphorus removal and the lower N/P at 15 showed the stronger synergistic effect between phosphorus and nitrogen removals. Compared with PO 3 - and P 2 O 7 4- in influent, PO 4 3- affected phosphorus removal more significantly. The better linear fitting between organic phosphorus removal and nitrogen removal in influent contained P 2 O 7 4- was found. Algae can absorb nutrients for growth, and oxygen release, microbial activity intensification and microbial carbon replenishment induced by algae will improve the performance. The study suggested that the control of HRTs, N/Ps, CCs, and algae might be an effective way to improve wastewater treatment performance. Copyright © 2016 Elsevier B.V. All rights reserved.

Mechanism of charged pollutants removal in an ion exchange membrane bioreactor: drinking water denitrification.

PubMed

Velizarov, S; Rodrigues, C M; Reis, M A; Crespo, J G

The mechanism of anionic pollutant removal in an ion exchange membrane bioreactor (IEMB) was studied for drinking water denitrification. This hybrid process combines continuous ion exchange transport (Donnan dialysis) of nitrate and its simultaneous bioreduction to gaseous nitrogen. A nonporous mono-anion permselective membrane precludes direct contact between the polluted water and the denitrifying culture and prevents secondary pollution of the treated water with dissolved nutrients and metabolic products. Complete denitrification may be achieved without accumulation of NO3(-) and NO2(-) ions in the biocompartment. Focus was given to the effect of the concentration of co-ions, counterions, and ethanol on the IEMB performance. The nitrate overall mass transfer coefficient in this hybrid process was found to be 2.8 times higher compared to that in a pure Donnan dialysis process without denitrification. Furthermore, by adjusting the ratio of co-ions between the biocompartment and the polluted water compartment, the magnitude and direction of each individual anion flux can be easily regulated, allowing for flexible process operation and control. Synthetic groundwater containing 135-350 mg NO3(-) L(-1) was treated in the IEMB system. A surface denitrification rate of 33 g NO3(-) per square meter of membrane per day was obtained at a nitrate loading rate of 360 g NO3(-) m(-3)d(-1), resulting in a nitrate removal efficiency of 85%.

Comparison of Removal Behavior of Two Biotrickling Filters under Transient Condition and Effect of pH on the Bacterial Communities

PubMed Central

Tu, Xiang; Li, Jianjun; Feng, Rongfang; Sun, Guoping; Guo, Jun

2016-01-01

Although biotrickling filters (BTFs) applied under acidic condition to remove H2S from waste gases have been reported, the removal behavior of the acidic BTF under transient condition which was normal in most industry processes, and corresponding bacterial community have not been thoroughly studied. In the present study, two BTFs were run under neutral (BTFn) and acidic (BTFa) conditions, respectively. The results revealed that the removal performance of BTFa under transient condition was superior to that of BTFn; the maximum H2S eliminating capacities (ECs) achieved by BTFa and BTFn were 489.9 g/m3 h and 443.6 g/m3 h, respectively. High-throughput sequencing suggested that pH was the critical factor and several other factors including nutrient and the inlet loadings also had roles in shaping bacterial community structure. Acidithiobacillus was the most abundant bacterial group. The results indicated that BTF acclimation under acidic condition may facilitate generating microbial community with high H2S-degrading capability. PMID:27196300

Improvement of the degradation of sulfate rich wastewater using sweetmeat waste (SMW) as nutrient supplement.

PubMed

Das, Bidus Kanti; Roy, Shantonu; Dev, Subhabrata; Das, Debabrata; Bhattacharya, Jayanta

2015-12-30

External dosing of sweetmeat waste (SMW) dosing into exhausted upflow packed bed bioreactor (PBR) resulted in prompt reactivation of SO4(2-) removal. Different SMW concentrations in terms of chemical oxygen demand (COD)/SO4(2-) ratios (1, 2, 4 and 8) were introduced into four identical PBR where process stability was found within 3 weeks of operation. SO4(2-) removal was proportional to COD/SO4(2-) ratios up to 4 at which maximum sulfate removal (99%) was achieved at a rate of 607 mg/d. The value of COD consumption:SO4(2-)removal was much higher at ratio 4 than 8 whereas, ratio 2 was preferred over all. Net effluent acetate concentration profile and total microbial population attached to the reactor matrices were corresponding to COD/SO4(2-) ratio as 4>8>2>1. Sulfate reducing bacteria (SRB) population was found to be inversely proportional to COD/SO4(2-) ratio in which acetate oxidizing SRB and fermentative bacteria were the dominant. Copyright © 2015 Elsevier B.V. All rights reserved.

Study of the recovery of phosphorus from struvite precipitation in supernatant line from anaerobic digesters of sludge.

PubMed

Xavier, Luciano Dias; Cammarota, Magali Christe; Yokoyama, Lídia; Volschan Junior, Isaac

2014-01-01

The goal of this work was to study the effective recovery of phosphorus from the supernatant of anaerobic digestion of sewage sludge by precipitation as struvite. The formation of struvite is envisioned as a promising process for nutrient removal and subsequent recovery, thus providing a strong incentive for its implementation, since the sewage is a renewable source of phosphorus. Struvite precipitation was obtained by controlled addition of Mg(OH)2 or MgCl2. We evaluated the removal of ammonia and phosphate under equimolar conditions of magnesium and magnesium stoichiometric excess of 100 to 200% relative to the limiting reagent, under a stirring speed of 300 rpm at pH 8, 9 and 10. The best condition was MgCl2 in 1:1 molar ratio to phosphate, considering the stoichiometric ratio [PO4(3-)]:[NH4(+)] of 0.13 (presented by raw sample). The results show the best cost-benefit ratio, removal of phosphate of 90.6% and ammonium removal of 29%, resulting in 23 mg l(-1) PO4(3-) and 265 mg l(-1) NH4(+) concentration in effluent.

Feasibility of using brewery wastewater for biodiesel production and nutrient removal by Scenedesmus dimorphus.

PubMed

Lutzu, Giovanni Antonio; Zhang, Wei; Liu, Tianzhong

2016-01-01

This work investigates the potential use of a brewery wastewater as a medium for the cultivation of the oleaginous species Scenedesmus dimorphus with the double aim of removing nutrients and to produce biomass as feedstock for biodiesel. For this purpose, effects of nitrogen (61.8-247 mg L(-1)), phosphorous (1.4-5.5 mg L(-1)), and iron (1.5-6 mg L(-1)) concentrations on growth, nutrients uptake, lipid accumulation, and fatty acids profile of this microalga were investigated. Results showed that brewery wastewater can be used as a culture medium even if nitrogen and phosphorous concentrations should have been modified to improve both biomass (6.82 g L(-1)) and lipid accumulation (44.26%). The analysis revealed a C16-C18 composition of 93.47% fatty acids methyl esters with a relative high portion of unsaturated ones (67.24%). High removal efficiency (>99%) for total nitrogen and total phosphorous and a reduction of up to 65% in chemical oxygen demand were achieved, respectively. The final microalgae biomass, considering its high lipid content as well as its compliance with the standards for the quality of biodiesel, and considering also the high removal efficiencies obtained for macronutrients and organic carbon, makes the brewery wastewater a viable option as a priceless medium for the cultivation of microalgae.

Treatment of highway runoff : engineered filter media for pollutant removal through enhanced sorption : final report.

DOT National Transportation Integrated Search

2015-07-27

The work performed in this study focused on the investigation of the use of engineered biofiltration layers to enhance the removal of roadway stormwater runoff contaminants (specifically nutrients, solids, heavy metals, and pH). Six Georgia native gr...

Hydroponics reducing effluent's heavy metals discharge.

PubMed

Rababah, Abdellah; Al-Shuha, Ahmad

2009-01-01

This paper investigates the capacity of Nutrient Film Technique (NFT) to control effluent's heavy metals discharge. A commercial hydroponic system was adapted to irrigate lettuces with primary treated wastewater for studying the potential heavy metals removal. A second commercial hydroponic system was used to irrigate the same type of lettuces with nutrient solution and this system was used as a control. Results showed that lettuces grew well when irrigated with primary treated effluent in the commercial hydroponic system. The NFT-plant system heavy metals removal efficiency varied amongst the different elements, The system's removal efficiency for Cr was more than 92%, Ni more than 85%, in addition to more than 60% reduction of B, Pb, and Zn. Nonetheless, the NFT-plants system removal efficiencies for As, Cd and Cu were lower than 30%. Results show that lettuces accumulated heavy metals in leaves at concentrations higher than the maximum acceptable European and Australian levels. Therefore, non-edible plants such as flowers or pyrethrum are recommended as value added crops for the proposed NFT.

Assessing biological and chemical signatures related to nutrient removal by floating islands in stormwater mesocosms.

PubMed

Chang, Ni-Bin; Islam, Kamrul; Marimon, Zachary; Wanielista, Martin P

2012-07-01

Aquatic floating plants on BioHaven mats were tested for their potential use as a Best Management Practice to be incorporated within existing stormwater detention ponds. Plants were analyzed for their capability to remove nutrient-pollution in parallel with the study of ecological dynamics. Experiments were carried out in cylindrical mesocosms of 5 m diameter and 1.2 m height, above-ground pools with a water volume of 14 m(3). The design parameters tested were for 5% and 10% vegetated floating island coverage of the mesocosm, both with and without shoreline plants called littoral zone. This littoral shelf was 0.5 m thick, graded at a downward slope of 1:5 toward the center using loamy soil with low organic matter content, excavated from below turf grass. Endemic plant species were chosen for the experimental location in central Florida based on a wetland identification manual by the Florida Department of Environmental Protection to ensure the study was not compromised by unique climate requirements of the plants. Nutrient and aquatic chemical conditions such as pH, dissolved oxygen, temperature, turbidity, and chlorophyll a were monitored to understand their relationships to the general wetland ecosystem. Real-time polymerase chain reaction analysis identified the microbial activity near the rhizospheric zone. Logistical placement considerations were made using spatial sampling across the horizontal plane of the mesocosms, beneath and around the root zone, to determine if nutrients tend to aggregate around the floating island. This study concluded that the application of floating islands as a stormwater technology can remove nutrients through plant uptake and biological activity. The most cost-effective size in the outdoor mesocosms was 5% surface area coverage of the mat. Copyright © 2012 Elsevier Ltd. All rights reserved.

Nutrient Removal Vis-à-Vis Change in Partial Pressure of CO2 During Post-Monsoon Season in a Tropical Lentic and Lotic Aquatic Body: A Comparative Study

NASA Astrophysics Data System (ADS)

Bhattacharyya, Sourav; Chanda, Abhra; Das, Sourav; Akhand, Anirban; Pattanaik, Suchismita; Choudhury, S. B.; Dutta, Dibyendu; Hazra, Sugata

2018-04-01

The rate of nutrient removal and changes in pCO2 (water) were compared between a lentic aquaculture pond [East Kolkata Wetlands (EKW), India] and a lotic estuarine system [Diamond Harbor (DH) in Hugli Estuary, India] during the post-monsoon season (experiencing a similar tropical climate) by means of ex situ microcosm experiment. Though the DH waters were found to be substantial source of CO2 towards atmosphere and EKW waters to be sink for CO2 (according to the initial concentration of CO2), the eight consecutive days microcosm experiment revealed that the nutrient removal and pCO2 reduction efficiency were significantly higher in DH (ΔpCO2—90%) compared to EKW (ΔpCO2—78%). Among the five nutrients studied [dissolved nitrate-nitrogen (NO3-N), dissolved ammonium nitrogen (NH4-N), silicate, phosphate and iron], dissolved NO3-N followed by NH4-N was the most utilized in both EKW and DH. Except silicate, the other nutrients reduced to 78-91% in EKW and 84-99% in DH samples of their initial concentrations. Chlorophyll-a concentration steadily depleted in EKW ( 68-26 mg m-3) during the experiment indicating intense zooplankton grazing, whereas in DH it increased rapidly ( 3.4-23 mg m-3) with decreasing pCO2 (water). The present observations further indicated that regular flushing of EKW aquaculture ponds is required to avoid stagnation of water column which would enhance the zooplankton grazing and hamper the primary production of an otherwise sink of CO2. In DH, controlled freshwater discharge from Farakka and reduction of untreated organic waste might allow the existing phytoplankton community to enhance their photosynthetic activity.

Internal ecosystem feedbacks enhance nitrogen-fixing cyanobacteria blooms and complicate management in the Baltic Sea.

PubMed

Vahtera, Emil; Conley, Daniel J; Gustafsson, Bo G; Kuosa, Harri; Pitkänen, Heikki; Savchuk, Oleg P; Tamminen, Timo; Viitasalo, Markku; Voss, Maren; Wasmund, Norbert; Wulff, Fredrik

2007-04-01

Eutrophication of the Baltic Sea has potentially increased the frequency and magnitude of cyanobacteria blooms. Eutrophication leads to increased sedimentation of organic material, increasing the extent of anoxic bottoms and subsequently increasing the internal phosphorus loading. In addition, the hypoxic water volume displays a negative relationship with the total dissolved inorganic nitrogen pool, suggesting greater overall nitrogen removal with increased hypoxia. Enhanced internal loading of phosphorus and the removal of dissolved inorganic nitrogen leads to lower nitrogen to phosphorus ratios, which are one of the main factors promoting nitrogenfixing cyanobacteria blooms. Because cyanobacteria blooms in the open waters of the Baltic Sea seem to be strongly regulated by internal processes, the effects of external nutrient reductions are scale-dependent. During longer time scales, reductions in external phosphorus load may reduce cyanobacteria blooms; however, on shorter time scales the internal phosphorus loading can counteract external phosphorus reductions. The coupled processes inducing internal loading, nitrogen removal, and the prevalence of nitrogen-fixing cyanobacteria can qualitatively be described as a potentially self-sustaining "vicious circle." To effectively reduce cyanobacteria blooms and overall signs of eutrophication, reductions in both nitrogen and phosphorus external loads appear essential.

A low-cost municipal sewage treatment system with a combination of UASB and the "fourth-generation" downflow hanging sponge reactors.

PubMed

Tandukar, M; Uemura, S; Machdar, I; Ohashi, A; Harada, H

2005-01-01

This paper presents an evaluation of the process performance of a pilot-scale "fourth generation" downflow hanging sponge (DHS) post-treatment system combined with a UASB pretreatment unit treating municipal wastewater. After the successful operation of the second- and third-generation DHS reactors, the fourth-generation DHS reactor was developed to overcome a few shortcomings of its predecessors. This reactor was designed to further enhance the treatment efficiency and simplify the construction process in real scale, especially for the application in developing countries. Configuration of the reactor was modified to enhance the dissolution of air into the wastewater and to avert the possible clogging of the reactor especially during sudden washout from the UASB reactor. The whole system was operated at a total hydraulic retention time (HRT) of 8 h (UASB: 6 h and DHS: 2 h) for a period of over 600 days. The combined system was able to remove 96% of unfiltered BOD with only 9 mg/L remaining in the final effluent. Likewise, F. coli were removed by 3.45 log with the final count of 10(3) to 10(4) MPN/100 ml. Nutrient removal by the system was also satisfactory.

Nitrogen Removal over Nitrite by Aeration Control in Aerobic Granular Sludge Sequencing Batch Reactors

PubMed Central

Lochmatter, Samuel; Maillard, Julien; Holliger, Christof

2014-01-01

This study investigated the potential of aeration control for the achievement of N-removal over nitrite with aerobic granular sludge in sequencing batch reactors. N-removal over nitrite requires less COD, which is particularly interesting if COD is the limiting parameter for nutrient removal. The nutrient removal performances for COD, N and P have been analyzed as well as the concentration of nitrite-oxidizing bacteria in the granular sludge. Aeration phase length control combined with intermittent aeration or alternate high-low DO, has proven to be an efficient way to reduce the nitrite-oxidizing bacteria population and hence achieve N-removal over nitrite. N-removal efficiencies of up to 95% were achieved for an influent wastewater with COD:N:P ratios of 20:2.5:1. The total N-removal rate was 0.18 kgN·m−3·d−1. With N-removal over nitrate the N-removal was only 74%. At 20 °C, the nitrite-oxidizing bacteria concentration decreased by over 95% in 60 days and it was possible to switch from N-removal over nitrite to N-removal over nitrate and back again. At 15 °C, the nitrite-oxidizing bacteria concentration decreased too but less, and nitrite oxidation could not be completely suppressed. However, the combination of aeration phase length control and high-low DO was also at 15 °C successful to maintain the nitrite pathway despite the fact that the maximum growth rate of nitrite-oxidizing bacteria at temperatures below 20 °C is in general higher than the one of ammonium-oxidizing bacteria. PMID:25006970

Seasonal change in precipitation, snowpack, snowmelt, soil water and streamwater chemistry, northern Michigan

USGS Publications Warehouse

Stottlemyer, R.; Toczydlowski, D.

1999-01-01

We have studied weekly precipitation, snowpack, snowmelt, soil water and streamwater chemistry throughout winter for over a decade in a small (176 ha) northern Michigan watershed with high snowfall and vegetated by 60 to 80 year-old northern hardwoods. In this paper, we examine physical, chemical, and biological processes responsible for observed seasonal change in streamwater chemistry based upon intensive study during winter 1996-1997. The objective was to define the contributions made to winter and spring streamwater chemical concentration and flux by processes as snowmelt, over-winter forest floor and surface soil mineralization, immobilization, and exchange, and subsurface flowpath. The forest floor and soil were unfrozen beneath the snowpack which permitted most snowmelt to enter. Over-winter soil mineralization and other biological processes maintain shallow subsurface ion and dissolved organic carbon (DOC) reservoirs. Small, but steady, snowmelt throughout winter removed readily mobilized soil NO3- which resulted in high over-winter streamwater concentrations but little flux. Winter soil water levels and flowpaths were generally deep which increased soil water and streamwater base cation (C(B)), HCO3-, and Si concentrations. Spring snowmelt increased soil water levels and removal of ions and DOC from the biologically active forest floor and shallow soils. The snowpack solute content was a minor component in determining streamwater ion concentration or flux during and following peak snowmelt. Exchangeable ions, weakly adsorbed anions, and DOC in the forest floor and surface soils dominated the chemical concentration and flux in soil water and streamwater. Following peak snowmelt, soil microbial immobilization and rapidly increased plant uptake of limiting nutrients removed nearly all available nitrogen from soil water and streamwater. During the growing season high evapotranspiration increased subsurface flowpath depth which in turn removed weathering products, especially C(B), HCO3-, and Si, from deeper soils. Soil water was a major component in the hydrologic and chemical budgets.We have studied weekly precipitation, snowpack, snowmelt, soil water and streamwater chemistry throughout winter for over a decade in a small (176 ha) northern Michigan watershed with high snowfall and vegetated by 60 to 80 year-old northern hardwoods. In this paper, we examine physical, chemical, and biological processes responsible for observed seasonal change in streamwater chemistry based upon intensive study during winter 1996-1997. The objective was to define the contributions made to winter and spring streamwater chemical concentration and flux by processes as snowmelt, over-winter forest floor and surface soil mineralization, immobilization, and exchange, and subsurface flowpath. The forest floor and soils were unfrozen beneath the snowpack which permitted most snowmelt to enter. Over-winter soil mineralization and other biological processes maintain shallow subsurface ion and dissolved organic carbon (DOC) reservoirs. Small, but steady, snowmelt throughout winter removed readily mobilized soil NO3- which resulted in high over-winter streamwater concentrations but little flux. Winter soil water levels and flowpaths were generally deep which increased soil water and streamwater base cation (CB), HCO3-, and Si concentrations. Spring snowmelt increased soil water levels and removal of ions and DOC from the biologically active forest floor and shallow soils. The snowpack solute content was a minor component in determining streamwater ion concentration or flux during and following peak snowmelt. Exchangeable ions, weakly adsorbed anions, and DOC in the forest floor and surface soils dominated the chemical concentration and flux in soil water and streamwater. Following peak snowmelt, soil microbial immobilization and rapidly increased plant uptake of limiting nutrients removed nearly all available nitrogen from soil water and streamwater. D

Nutrient removal and greenhouse gas emissions in duckweed treatment ponds.

PubMed

Sims, Atreyee; Gajaraj, Shashikanth; Hu, Zhiqiang

2013-03-01

Stormwater treatment ponds provide a variety of functions including sediment retention, organic and nutrient removal, and habitat restoration. The treatment ponds are, however, also a source of greenhouse gases. The objectives of this study were to assess greenhouse gas (CH(4), CO(2) and N(2)O) emissions in duckweed treatment ponds (DWPs) treating simulated stormwater and to determine the role of ammonia-oxidizing organisms in nutrient removal and methanogens in greenhouse gas emissions. Two replicated DWPs operated at a hydraulic retention time (HRT) of 10 days were able to remove 84% (± 4% [standard deviation]) chemical oxygen demand (COD), 79% (± 3%) NH(4)(+)-N, 86% (± 2%) NO(3)(-)-N and 56% (± 7%) orthophosphate. CH(4) emission rates in the DWPs ranged from 502 to 1900 mg CH(4) m(-2) d(-1) while those of nitrous oxide (N(2)O) ranged from 0.63 to 4 mg N(2)O m(-2) d(-1). The CO(2) emission rates ranged from 1700 to 3300 mg CO(2) m(-2) day(-1). Duckweed coverage on water surface along with the continued deposit of duckweed debris in the DWPs and low-nutrient influent water created a low dissolved oxygen environment for the growth of unique ammonia-oxidizing organisms and methanogens. Archaeal and bacterial amoA abundance in the DWPs ranged from (1.5 ± 0.2) × 10(7) to (1.7 ± 0.2) × 10(8) copies/g dry soil and from (1.0 ± 0.3) × 10(3) to (1.5 ± 0.4) × 10(6) copies/g dry soil, respectively. The 16S rRNA acetoclastic and hydrogenotrophic methanogens ranged from (5.2 ± 0.2) × 10(5) to (9.0 ± 0.3) × 10(6) copies/g dry soil and from (1.0 ± 0.1) × 10(2) to (5.5 ± 0.4) × 10(3) copies/g dry soil, respectively. Ammonia-oxidizing archaea (AOA) appeared to be the dominant nitrifiers and acetoclastic Methanosaeta was the major methanogenic genus. The results suggest that methane is the predominant (>90%) greenhouse gas in the DWPs, where the relatively low stormwater nutrient inputs facilitate the growth of K-strategists such as AOA and Methanosaeta that may be responsible for ammonia removal and greenhouse gas emissions, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Is groundwater discharge the dominant source of nutrients to Alabama estuaries and will it keep impacting these waters for the foreseeable future?

NASA Astrophysics Data System (ADS)

Mortazavi, B.; Domangue, R.; Kleinhuizen, A.; Tatariw, C.

2017-12-01

Land use change and population growth are dominant factors impacting coastal waters. Populations in Alabama coastal counties have increased by several folds since the 1950s and a large fraction of the farmed land are now being used for growing sod requiring large amounts of fertilizers. Concurrent with these changes, marshes bordering Mobile Bay have been disappearing such that they now only cover 50% of their areal extent compared to the 1780s. These changes in land use and coastal geomorphology, as well as the population growth ultimately result in larger delivery of nutrients either through runoff or groundwater discharge to the coastal waters. The Mobile Bay estuary in Alabama is bordered with several subestuaries and a coastal lagoon. Our investigations suggest that the large inputs of nutrients through river discharge in Weeks Bay (140 g N m-2 yr-1) and groundwater discharge in Little Lagoon (300 g N m-2 yr-1) by far dominate inputs of N to the water column and exceed N input, for example, from benthic regeneration, by an order of magnitude. Furthermore, the capacity for N removal through denitrification in these systems is low and instead nitrogen is retained through dissimilatory nitrate reduction to ammonium at a rate that exceed denitrification by an order of magnitude. Our measurements also suggest that once marshes are transformed to subtidal unvegetated sediments rates of nitrogen removal by denitrification decline four folds. Excessive inputs of nitrogen and the high efficiency with which nitrogen is retained in these systems is impacting the foodweb and harmful algal blooms and fish kills are reoccurring events. While changes in agricultural practices and reconstruction of marshes can potentially reduce the delivery of N or enhance N removal by denitrification, nutrient inputs through groundwater discharge are going to impact these estuaries for the foreseeable future. Our capacity to construct nutrient budgets and to predict the trajectory of ecosystem changes will therefore depend greatly on accurate knowledge of groundwater discharge to these systems. Quantifying the magnitudes of groundwater derived nutrients and the fate of these nutrients in nearshore systems requires concerted efforts amongst hydrologists, biogeochemists, and ecologists.

Denitrification and Phosphorus Sequestration in Restored Oyster Beds in the Indian River Lagoon, Florida, USA

NASA Astrophysics Data System (ADS)

Gallagher, S. M.; Schmidt, C. A.; Walters, L.

2016-12-01

In 2016, an algae bloom in the St. Lucie River in Florida led the governor to declare a state of emergency. The river is part of a connected system of estuaries along the Atlantic coast of Florida called the Indian River Lagoon (IRL). As with many estuaries around the world, nutrient loading in the IRL has led to periodic eutrophication. As a result, much research has been done to address nutrients in these systems. Previous estuary studies have related oyster restoration to denitrification and phosphorus sequestration in their bed sediment. To this point, these studies have been inconclusive, and have only focused on seasonal variation in nutrient cycling. In 2007, yearly oyster bed installation and restoration began in a study area in the IRL. By 2016, beds aged up to eleven years were available for sampling. This unique advantage allowed investigation of bed sediment and nutrient cycling over long periods of time. Sediment from the IRL was measured for organic matter, microbial weight, carbon, nitrogen, and phosphorus. Denitrification was measured using an acetylene block technique. A statistical analysis was used to find differences in sediment characteristics and denitrification between restored beds and control sites over time. In addition, sequencing of 16S rRNA DNA and a variety of denitrifying genes was used to identify bacterial species and their denitrifying capability in the sediment. The ability to sequence denitrification genes in established oyster beds over a period of years was also unique to this study. Significant differences were found in soil properties, denitrification rates, and phosphorus sequestration between control sites and restored oyster beds. Gene sequencing also found differences in bacterial populations between the sites. Oyster bed restoration resulted in a rapid increase in nutrient removal as beds developed over three years, but additional benefits were limited as restoration progressed further. This study adds an investigation of IRL oysters to existing knowledge of nutrient removal by oysters in other estuaries. These results help clarify single year studies focused on seasonal changes by showing a rapid increase in oyster bed nutrient removal over a period of three years.

Investigation of the potential of Cyperus alternifolius in the phytoremediation of palm oil mill effluent

NASA Astrophysics Data System (ADS)

Sa'at, Siti Kamariah Md; Zaman, Nastaein Qamaruz; Yusoff, Suffian Mohd; Ismail, Hirun Azaman

2017-10-01

Phytoremediation is an emerging technology nowadays due to demand in environmental sustainability which requires cost-effective solutions in terms of capital and operational cost. The treatment gain attention due to their potential in wastewater treatment especially in organics, nutrients, and heavy metal removal of domestics, agricultural, and industrial wastewater treatment. Plant functions in phytoremediation make the plant selection as an essential element. The plant should have the ability to tolerate with the toxic effluent and able to uptake the contaminant. Cyperus alternifolius (umbrella grass) was chosen as aquatic plant due to the ability to tolerance in municipal and industrial effluent sources with strong and dense root systems. Thus, the objectives of this study are to determine the potential and effectiveness of Cyperus alternifolius in the palm oil mill effluent treatment especially in the removal of organics (COD), nutrients (NH3-N and TP) and suspended solid. The batch experiment was run using Cyperus alternifolius to determine their potential of aerobic pond effluent for 21 days of treatment. Cyperus alternifolius treatment shows the great removal of COD and TSS with 96% and 91%, respectively at the end of 21 days of treatment. Nutrients removal achieved the maximum removal of 92% NH3-N and 99% TP shows after 11 days of treatment and percentage slowly decrease until the end of 21 days of treatment. Cyperus alternifolius had shown potential in the palm oil mill effluent treatment and can be combined with ponding treatment to enhance to water quality prior discharge.

Sediment Budgets and Sources Inform a Novel Valley Bottom Restoration Practice Impacted by Legacy Sediment: The Big Spring Run, PA, Restoration Experiment

NASA Astrophysics Data System (ADS)

Walter, R. C.; Merritts, D.; Rahnis, M. A.; Gellis, A.; Hartranft, J.; Mayer, P. M.; Langland, M.; Forshay, K.; Weitzman, J. N.; Schwarz, E.; Bai, Y.; Blair, A.; Carter, A.; Daniels, S. S.; Lewis, E.; Ohlson, E.; Peck, E. K.; Schulte, K.; Smith, D.; Stein, Z.; Verna, D.; Wilson, E.

2017-12-01

Big Spring Run (BSR), a small agricultural watershed in southeastern Pennsylvania, is located in the Piedmont Physiographic Province, which has the highest nutrient and sediment yields in the Chesapeake Bay watershed. To effectively reduce nutrient and sediment loading it is important to monitor the effect of management practices on pollutant reduction. Here we present results of an ongoing study, begun in 2008, to understand the impact of a new valley bottom restoration strategy for reducing surface water sediment and nutrient loads. We test the hypotheses that removing legacy sediments will reduce sediment and phosphorus loads, and that restoring eco-hydrological functions of a buried Holocene wetland (Walter & Merritts 2008) will improve surface and groundwater quality by creating accommodation space to trap sediment and process nutrients. Comparisons of pre- and post-restoration gage data show that restoration lowered the annual sediment load by at least 118 t yr-1, or >75%, from the 1000 m-long restoration reach, with the entire reduction accounted for by legacy sediment removal. Repeat RTK-GPS surveys of pre-restoration stream banks verified that >90 t yr-1 of suspended sediment was from bank erosion within the restoration reach. Mass balance calculations of 137Cs data indicate 85-100% of both the pre-restoration and post-restoration suspended sediment storm load was from stream bank sources. This is consistent with trace element data which show that 80-90 % of the pre-restoration outgoing suspended sediment load at BSR was from bank erosion. Meanwhile, an inventory of fallout 137Cs activity from two hill slope transects adjacent to BSR yields average modern upland erosion rates of 2.7 t ha-1 yr-1 and 5.1 t ha-1 yr-1, showing modest erosion on slopes and deposition at toe of slopes. We conclude that upland farm slopes contribute little soil to the suspended sediment supply within this study area, and removal of historic valley bottom sediment effectively reduced bank erosion and sediment and phosphorus loads. Enhanced deposition further contributed to load reductions; prior to restoration, there was no deposition on tile pads on the 1.5 m-high legacy sediment "floodplain" terrace, whereas after restoration deposition on the low, restored floodplain showed net accumulation of 0.009 ± 0.012 m yr-1.

Polyhydroxyalkanoate (PHA) production from waste.

PubMed

Rhu, D H; Lee, W H; Kim, J Y; Choi, E

2003-01-01

PHA (polyhydroxyalkanoate) production was attempted with SBRs from food waste. Seed microbes were collected from a sewage treatment plant with a biological nutrient removal process, and acclimated with synthetic substrate prior to the application of the fermented food waste. Laboratory SBRs were used to produce PHA with limited oxygen and nutrients. The maximum content of 51% PHA was obtained with an anaerobic/aerobic cycle with P limitation, and the yield was estimated to be about 0.05 gPHA(produced)/gCOD(applied) or 25 kg PHA/dry ton of food waste, assuming more than 40% of the PHA contents were recoverable. PHB/PHA ratios were 0.74 to 0.77 due to the higher acetate concentrations. Economical analysis seemed to suggest the PHA produced from the food waste could be an alternative material to produce the biodegradable plastic to be used for the collection bags for solid waste.

Nitrogen-limited mangrove ecosystems conserve N through dissimilatory nitrate reduction to ammonium.

PubMed

Fernandes, Sheryl Oliveira; Bonin, Patricia C; Michotey, Valérie D; Garcia, Nicole; LokaBharathi, P A

2012-01-01

Earlier observations in mangrove sediments of Goa, India have shown denitrification to be a major pathway for N loss. However, percentage of total nitrate transformed through complete denitrification accounted for <0-72% of the pore water nitrate reduced. Here, we show that up to 99% of nitrate removal in mangrove sediments is routed through dissimilatory nitrate reduction to ammonium (DNRA). The DNRA process was 2x higher at the relatively pristine site Tuvem compared to the anthropogenically-influenced Divar mangrove ecosystem. In systems receiving low extraneous nutrient inputs, this mechanism effectively conserves and re-circulates N minimizing nutrient loss that would otherwise occur through denitrification. In a global context, the occurrence of DNRA in mangroves has important implications for maintaining N levels and sustaining ecosystem productivity. For the first time, this study also highlights the significance of DNRA in buffering the climate by modulating the production of the greenhouse gas nitrous oxide.

Understanding the fate of sanitation-related nutrients in a shallow sandy aquifer below an urban slum area

NASA Astrophysics Data System (ADS)

Nyenje, P. M.; Havik, J. C. N.; Foppen, J. W.; Muwanga, A.; Kulabako, R.

2014-08-01

We hypothesized that wastewater leaching from on-site sanitation systems to alluvial aquifers underlying informal settlements (or slums) may end up contributing to high nutrient loads to surface water upon groundwater exfiltration. Hence, we conducted a hydro-geochemical study in a shallow sandy aquifer in Bwaise III parish, an urban slum area in Kampala, Uganda, to assess the geochemical processes controlling the transport and fate of dissolved nutrients (NO3, NH4 and PO4) released from on-site sanitation systems to groundwater. Groundwater was collected from 26 observation wells. The samples were analyzed for major ions (Ca, Mg, Na, Mg, Fe, Mn, Cl and SO4) and nutrients (o-PO4, NO3 and NH4). Data was also collected on soil characteristics, aquifer conductivity and hydraulic heads. Geochemical modeling using PHREEQC was used to determine the level of o-PO4 control by mineral solubility and sorption. Groundwater below the slum area was anoxic and had near neutral pH values, high values of EC (average of 1619 μS/cm) and high concentrations of Cl (3.2 mmol/L), HCO3 (11 mmol/L) and nutrients indicating the influence from wastewater leachates especially from pit latrines. Nutrients were predominantly present as NH4 (1-3 mmol/L; average of 2.23 mmol/L). The concentrations of NO3 and o-PO4 were, however, low: average of 0.2 mmol/L and 6 μmol/L respectively. We observed a contaminant plume along the direction of groundwater flow (NE-SW) characterized by decreasing values of EC and Cl, and distinct redox zones. The redox zones transited from NO3-reducing in upper flow areas to Fe-reducing in the lower flow areas. Consequently, the concentrations of NO3 decreased downgradient of the flow path due to denitrification. Ammonium leached directly into the alluvial aquifer was also partially removed because the measured concentrations were less than the potential input from pit latrines (3.2 mmol/L). We attributed this removal (about 30%) to anaerobic ammonium oxidation (anammox) given that the cation exchange capacity of the aquifer was low (< 6 meq/100 g) to effectively adsorb NH4. Phosphate transport was, on the other hand, greatly retarded and our results showed that this was due to the adsorption of P to calcite and the co-precipitation of P with calcite and rhodochrosite. Our findings suggest that shallow alluvial sandy aquifers underlying urban slum areas are an important sink of excessive nutrients leaching from on-site sanitation systems.

Optimizing T Cell Expansion in a Hollow-Fiber Bioreactor.

PubMed

Nankervis, Brian; Jones, Mark; Vang, Boah; Brent Rice, R; Coeshott, Claire; Beltzer, Jim

2018-01-01

Recent developments in regenerative medicine have precipitated the need to expand gene-modified human T cells to numbers that exceed the capacity of well-plate-based, and flask-based processes. This review discusses the changes in process development that are needed to meet the cell expansion requirements by utilizing hollow-fiber bioreactors . Maintenance of cell proliferation over long periods can become limited by unfilled demands for nutrients and oxygen and by the accumulation of waste products in the local environment. Perfusion feeding, improved gas exchange, and the efficient removal of lactate can increase the yield of T cells from an average of 10.8E +09 to more than 28E +09 in only 10 days. Aggressively feeding cells and actively keeping cells in the bioreactor improves gas exchange and metabolite management over semi-static methods. The ability to remove the environmental constraints that can limit cell expansion by using a two-chamber hollow-fiber bioreactor will be discussed.

Poultry slaughterhouse wastewater treatment plant for high quality effluent.

PubMed

Del Nery, V; Damianovic, M H Z; Moura, R B; Pozzi, E; Pires, E C; Foresti, E

2016-01-01

This paper assesses a wastewater treatment plant (WWTP) regarding the technology used, as well as organic matter and nutrient removal efficiencies aiming to optimize the treatment processes involved and wastewater reclamation. The WWTP consists of a dissolved air flotation (DAF) system, an upflow anaerobic sludge blanket (UASB) reactor, an aerated-facultative pond (AFP) and a chemical-DAF system. The removal efficiencies of chemical oxygen demand (COD) (97.9 ± 1.0%), biochemical oxygen demand (BOD) (98.6 ± 1.0%) and oil and grease (O&G) (91.1 ± 5.2%) at the WWTP, the nitrogen concentration of 17 ± 11 mg N-NH3 and phosphorus concentration of 1.34 ± 0.93 mg PO4(-3)/L in the final effluent indicate that the processes used are suitable to comply with discharge standards in water bodies. Nitrification and denitrification tests conducted using biomass collected at three AFP points indicated that nitrification and denitrification could take place in the pond.

Fixed-bed biosorption of cadmium using immobilized Scenedesmus obliquus CNW-N cells on loofa (Luffa cylindrica) sponge.

PubMed

Chen, Bor-Yann; Chen, Chun-Yen; Guo, Wan-Qian; Chang, Hao-Wei; Chen, Wen-Ming; Lee, Duu-Jong; Huang, Chieh-Chen; Ren, Nan-Qi; Chang, Jo-Shu

2014-05-01

A continuous fixed-bed biosorption process was established for cadmium (Cd) removal by Scenedesmus obliquus CNW-N (isolated from southern Taiwan) cells immobilized onto loofa sponge. This immobilized-cell biosorption process allows better recovery and reusability of the microalgal biomass. The growth of microalgae on the matrix support with appropriate nutrient supplementation could enhance the overall metal removal activity. Major operating parameters (e.g., feeding flow rate, cycle number of medium replacement, and particle diameter of the sponge) were studied for treatability evaluation. The most promising cell growth on the sponge support was obtained at a flow rate of 0.284 bed volume (BV)/min, sponge particle diameter of 1 cm, and with one cycle of medium replacement. The performance of fixed-bed biosorption (adsorption capacity of 38.4 mg, breakthrough time at 15.5 h) was achieved at a flow rate of 5 ml/min with an influent concentration of 7.5 mg Cd/l. Copyright © 2014 Elsevier Ltd. All rights reserved.

Idaho forest growth response to post-thinning energy biomass removal and complementary soil amendments

Treesearch

Lauren A. Sherman; Deborah S. Page-Dumroese; Mark D. Coleman

2018-01-01

Utilization of woody biomass for biofuel can help meet the need for renewable energy production. However, there is a concern biomass removal will deplete soil nutrients, having short- and long-term effects on tree growth. This study aimed to develop short-term indicators to assess the impacts of the first three years after small-diameter woody biomass removal on forest...

Regulation of bone remodeling by vitamin K2.

PubMed

Myneni, V D; Mezey, E

2017-11-01

All living tissues require essential nutrients such as amino acids, fatty acids, carbohydrates, minerals, vitamins, and water. The skeleton requires nutrients for development, maintaining bone mass and density. If the skeletal nutritional requirements are not met, the consequences can be quite severe. In recent years, there has been growing interest in promotion of bone health and inhibition of vascular calcification by vitamin K2. This vitamin regulates bone remodeling, an important process necessary to maintain adult bone. Bone remodeling involves removal of old or damaged bone by osteoclasts and its replacement by new bone formed by osteoblasts. The remodeling process is tightly regulated, when the balance between bone resorption and bone formation shifts to a net bone loss results in the development of osteoporosis in both men and women. In this review, we focus on our current understanding of the effects of vitamin K2 on bone cells and its role in prevention and treatment of osteoporosis. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Grazer removal and nutrient enrichment as recovery enhancers for overexploited rocky subtidal habitats.

PubMed

Guarnieri, Giuseppe; Bevilacqua, Stanislao; Vignes, Fabio; Fraschetti, Simonetta

2014-07-01

Increasing anthropogenic pressures are causing long-lasting regime shifts from high-diversity ecosystems to low-diversity degraded ones. Understanding the effects of multiple threats on ecosystems, and identifying processes allowing for the recovery of biodiversity, are the current major challenges in ecology. In several temperate marine areas, large parts of rocky subtidal habitats characterised by high diversity have been completely degraded to barren grounds by overfishing, including illegal date mussel fishing. Bare areas are characterized by the dominance of sea urchins whose grazing perpetuates the impact of overfishing. We investigated experimentally the separate and combined effects of nutrient enrichment and sea urchin exclusion on the recovery of barren grounds. Our results indicate that the two factors have a synergistic effect leading to the re-establishment of erect macroalgal canopies, enhancing the structural complexity of subtidal assemblages. In particular, in the overfished system considered here, the recovery of disturbed assemblages could occur only if sea urchins are removed. However, the recolonization of barren grounds by erect macroalgae is further enhanced under enriched conditions. This study demonstrates that the recovery of dramatically depleted marine habitats is possible, and provides useful indications for specific management actions, which at present are totally lacking, to achieve the restoration of barren grounds caused by human activity.

Hillslope nutrient dynamics following upland riparian vegetation disturbance

Treesearch

J. Alan Yeakley; David C. Coleman; Bruce L. Haines; Brian D. Kloeppel; Judy L. Meyer; Wayne T. Swank; Barry W. Argo; James M. Deal; Sharon F. Taylor

2003-01-01

We investigated the effects of removing nearstream Rhododendron and of the natural blowdown of canopy trees on nutrient export to streams in the southern Appalachians. Transects were instrumented on adjacent hillslopes in a first-order watershed at the Coweeta Hydrologic Laboratory (35°03'N, 83°25'W). Dissolved organic carbon (DOC), K+...

Weed management, training, and irrigation practices for organic production of trailing blackberry: III. Accumulation and removal of aboveground biomass, carbon, and nutrients

USDA-ARS?s Scientific Manuscript database

The effects of various production practices on biomass, C, and nutrient content, accumulation, and loss were assessed over 2 years in a mature organic trailing blackberry (Rubus L. subgenus Rubus, Watson) production system. Treatments included two irrigation options (no irrigation after harvest and ...

International Conference on Snow Hydrology: The Integration of Physical, Chemical, and Biological Systems Held in Brownsville, Vermont on 6-9 October 1998

DTIC Science & Technology

1998-08-01

5 Estimating Snowmelt Infiltration into Frozen Soils L . Zhao and D .M . G ray...andY Matsuura ......................................................... 17 Effect of Subalpine Canopy Removal on Snowpack, Soil Solution, and Nutrient...Tonnessen, and K. Heuer ..................................................................... 26 Snow Depth. Soil Frost, and Nutrient Loss in a Northern

Effects of vegetations and temperature on nutrient removal and microbiology in horizontal subsurface low constructed wetland for treatment of domestic sewage

USDA-ARS?s Scientific Manuscript database

The direct discharge of untreated domestic wastewater represents a major source of nutrients entering into aquatic environments, which may cause serious ecological problems, e.g., eutrophication. In this regard, low-cost and easily managed technologies such as constructed wetlands (CWs) provide a go...

Nutrient availability constrains the hydraulic architecture and water relations of savannah trees.

Treesearch

S.J. Bucci; F.G. Scholz; G. Goldstein; F.C. Meinzer; A.C. Franco; P.I. Campanello; R. Villalobos-Vega; M. Bustamante; F. Miralles-Wilhelm

2006-01-01

Several plant functional traits were studied in five dominant woody savanna species in a Brazilian savanna to determine whether removal of nutrient limitations has an effect on carbon allocation, water relations, and hydraulic architecture. Four treatments consisting of a control, and nitrogen (N), phosphorus (P), and N plus P additions were maintained for 5 years....

Assessment of Two Different Drinking Water Treatment Plants for the Removal of Free-living Amoebae, Egypt.

PubMed

Al-Herrawy, Ahmad Z; Gad, Mahmoud A

2017-01-01

The aim of this study was to compare between slow and rapid sand filters for the removal of free-living amoebae during drinking water treatment production. Overall, 48 water samples were collected from two drinking water treatment plants having two different filtration systems (slow and rapid sand filters) and from inlet and outlet of each plant. Water samples were collected from Fayoum Drinking Water and Wastewater Holding Company, Egypt, during the year 2015. They were processed for detection of FLAs using non-nutrient agar (NNA). The isolates of FLAs were microscopically identified to the genus level based on the morphologic criteria and molecularly confirmed by the aid of PCR using genus-specific primers. The percentage of removal for FLAs through different treatment processes reached its highest rate in the station using slow sand filters (83%), while the removal by rapid sand filter system was 71.4%. Statistically, there was no significant difference ( P =0.55) for the removal of FLAs between the two different drinking water treatment systems. Statistically, seasons had no significant effect on the prevalence of FLAs in the two different drinking water treatment plants. Morphological identification of the isolated FLAs showed the presence of 3 genera namely Acanthamoeba , Naegleria , and Vermamoeba ( Hartmannella ) confirmed by PCR. The appearance of FLAs especially pathogenic amoebae in completely treated drinking water may cause potential health threat although there is no statistical difference between the two examined drinking water filtration systems.

Wastewater influences nitrogen dynamics in a coastal catchment during a prolonged drought

PubMed Central

Hoellein, Timothy J.; Mooney, Rae F.; Gardner, Wayne S.; Buskey, Edward J.

2017-01-01

Abstract Ecosystem function measurements can enhance our understanding of nitrogen (N) delivery in coastal catchments across river and estuary ecosystems. Here, we contrast patterns of N cycling and export in two rivers, one heavily influenced by wastewater treatment plants (WWTP), in a coastal catchment of south Texas. We measured N export from both rivers to the estuary over 2 yr that encompass a severe drought, along with detailed mechanisms of N cycling in river, tidal river, and two estuary sites during prolonged drought. WWTP nutrient inputs stimulated uptake of N, but denitrification resulting in permanent N removal accounted for only a small proportion of total uptake. During drought periods, WWTP N was the primary source of exported N to the estuary, minimizing the influence of episodic storm‐derived nutrients from the WWTP‐influenced river to the estuary. In the site without WWTP influence, the river exported very little N during drought, so storm‐derived nutrient pulses were important for delivering N loads to the estuary. Overall, N is processed from river to estuary, but sustained WWTP‐N loads and periodic floods alter the timing of N delivery and N processing. Research that incorporates empirical measurements of N fluxes from river to estuary can inform management needs in the face of multiple anthropogenic stressors such as demand for freshwater and eutrophication. PMID:29263559

Investigation of the effectiveness of nutrient release from sludge foam after hybrid pretreatment processes by IR analysis and EDX Quantification.

PubMed

Machnicka, Alicja; Grübel, Klaudiusz

2016-12-01

One of the problems in wastewater treatment technologies is the formation of foam/scum. It is thought that filamentous microorganisms are responsible for foam formation and foam elimination/destruction can be carried out by various methods, among which disintegration is included. Hybrid disintegration (chemical decomposition and hydrodynamic cavitation) of foam microorganisms results in the transfer of phosphates, ammonium nitrogen, magnesium and potassium from the foam solids into the liquid phase. Application of both methods as a hybrid pretreatment process caused an increase in the concentration of phosphates of about 650 mg [Formula: see text] L(-1) and ammonium nitrogen of about 30 mg [Formula: see text] L(-1). The concentration of Mg(2+) and K(+) in the solution increased from 6.8 and 26.1 mg Mg(2+) L(-1) to 32.2 and 82.2 mg K(+) L(-1), respectively. The presence of nutrients and metal cations in the solid phase of foam was acknowledged by EDX Quantification. The confirmation of physico-chemical changes and release of cellular matter as a result of cellular lysis (hybrid disintegration) was done by infrared analysis. It was demonstrated that the disintegration of foam permits the removal of a part of nutrients in the form of struvite.

Development of natural treatment system consisting of black soil and Kentucky bluegrass for the post-treatment of anaerobically digested strong wastewater.

PubMed

Chen, Xiaochen; Fukushi, Kensuke

2016-03-01

To develop a sound post-treatment process for anaerobically-digested strong wastewater, a novel natural treatment system comprising two units is put forward. The first unit, a trickling filter, provides for further reduction of biochemical oxygen demand and adjustable nitrification. The subsequent soil-plant unit aims at removing and recovering the nutrients nitrogen (N), phosphorus (P) and potassium (K). As a lab-scale feasibility study, a soil column test was conducted, in which black soil and valuable Kentucky bluegrass were integrated to treat artificial nutrient-enriched wastewater. After a long-term operation, the nitrification function was well established in the top layers, despite the need for an improved denitrification process prior to discharge. P and K were retained by the soil through distinct mechanisms. Since they either partially or totally remained in plant-available forms in the soil, indirect nutrient reuse could be achieved. As for Kentucky bluegrass, it displayed better growth status when receiving wastewater, with direct recovery of 8%, 6% and 14% of input N, P and K, respectively. Furthermore, the indispensable role of Kentucky bluegrass for better treatment performance was proved, as it enhanced the cell-specific nitrification potential of the soil nitrifying microorganisms inhabiting the rhizosphere. After further upgrade, the proposed system is expected to become a new solution for strong wastewater pollution. Copyright © 2015. Published by Elsevier B.V.

Inorganic arsenic removal in rice bran by percolating cooking water.

PubMed

Signes-Pastor, Antonio J; Carey, Manus; Meharg, Andrew A

2017-11-01

Rice bran, a by-product of milling rice, is highly nutritious but contains very high levels of the non-threshold carcinogen inorganic arsenic (i-As), at concentrations around 1mg/kg. This i-As content needs to be reduced to make rice bran a useful food ingredient. Evaluated here is a novel approach to minimizing rice bran i-As content which is also suitable for its stabilization namely, cooking bran in percolating arsenic-free boiling water. Up to 96% of i-As removal was observed for a range of rice bran products, with i-As removal related to the volume of cooking water used. This process reduced the copper, potassium, and phosphorus content, but had little effect on other trace- and macro-nutrient elements in the rice bran. There was little change in organic composition, as assayed by NIR, except for a decrease in the soluble sugar and an increase, due to biomass loss, in dietary fiber. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using a Spectral Method to Evaluate Hyporheic Exchange and its Effect on Reach Scale Nitrate Removal.

NASA Astrophysics Data System (ADS)

Moren, I.; Worman, A. L. E.; Riml, J.

2017-12-01

Previous studies have shown that hyporheic exchange processes can be of great importance for the transport, retention and mass removal of nutrients in streams. Specifically, the flow of surface water through the hyporheic zone enhances redox-sensitive reactions such as coupled nitrification-denitrification. This self-cleaning capacity of streams can be utilized in stream restoration projects aiming to improve water quality by reconstructing the geomorphology of the streams. To optimize the effect of restoration actions we need quantitative understanding of the linkage between stream geomorphology, hyporheic exchange processes and the desired water quality targets. Here we propose an analytical, spectral methodology to evaluate how different stream geomorphologies induce hyporheic exchange on a wide range of spatial and temporal scales. Measurements of streambed topographies and surface water profiles from agricultural streams were used to calculate the average hyporheic exchange velocity and residence times and the result was compared with in-stream tracer test. Furthermore, the hyporheic exchange induced by steps in the surface water profile was derived as a comparison of the theoretical capacity of the system. Based on differences in hyporheic exchange, the mass removal of nitrate could be derived for the different geomorphologies. The maximum nitrate mass removal was found to be related to a specific Damkhöler number, which reflects that the mass removal can be either reaction or transport controlled. Therefore, although hyporheic exchange induced by steps in the surface water profile was generally larger than the hyporheic exchange in the observed natural reaches, this would not necessarily lead a larger nitrate mass removal provided that the hyporheic residence times are not long enough to facilitate denitrification processes. The study illustrates the importance to investigate a stream thoroughly before any remediation actions are implemented, specifically to evaluate if the mass removal is reaction or transport controlled.

Simulating phosphorus removal from a vertical-flow constructed wetland grown with C. alternifolius species

USDA-ARS?s Scientific Manuscript database

Vertical flow constructed wetland (VFCW) is a promising engineering technique for removal of excess nutrients and certain pollutants from wastewater and stormwater. The aim of this study was to develop a STELLA (Structural Thinking, Experiential Learning Laboratory with Animation) model for estimati...

Evaluation of a biological wastewater treatment system combining an OSA process with ultrasound for sludge reduction.

PubMed

Romero-Pareja, P M; Aragon, C A; Quiroga, J M; Coello, M D

2017-05-01

Sludge production is an undesirable by-product of biological wastewater treatment. The oxic-settling-anaerobic (OSA) process constitutes one of the most promising techniques for reducing the sludge produced at the treatment plant without negative consequences for its overall performance. In the present study, the OSA process is applied in combination with ultrasound treatment, a lysis technique, in a lab-scale wastewater treatment plant to assess whether sludge reduction is enhanced as a result of mechanical treatment. Reported sludge reductions of 45.72% and 78.56% were obtained for the two regimes of combined treatment tested in this study during two respective stages: UO1 and UO2. During the UO1 stage, the general performance and nutrient removal improved, obtaining 47.28% TN removal versus 21.95% in the conventional stage. However, the performance of the system was seriously damaged during the UO2 stage. Increases in dehydrogenase and protease activities were observed during both stages. The advantages of the combined process are not necessarily economic, but operational, as US treatment acts as contributing factor in the OSA process, inducing mechanisms that lead to sludge reduction in the OSA process and improving performance parameters. Copyright © 2016 Elsevier B.V. All rights reserved.

Microbial Bioreactor Development in the ALS NSCORT

NASA Astrophysics Data System (ADS)

Mitchell, Cary; Whitaker, Dawn; Banks, M. Katherine; Heber, Albert J.; Turco, Ronald F.; Nies, Loring F.; Alleman, James E.; Sharvelle, Sybil E.; Li, Congna; Heller, Megan

The NASA Specialized Center of Research and Training in Advanced Life Support (the ALS NSCORT), a partnership of Alabama A & M, Howard, and Purdue Universities, was established by NASA in 2002 to develop technologies that will reduce the Equivalent System Mass (ESM) of regenerative processes within future space life-support systems. A key focus area of NSCORT research has been the development of efficient microbial bioreactors for treatment of human, crop, and food-process wastes while enabling resource recovery. The approach emphasizes optimizing the energy-saving advantages of hydrolytic enzymes for biomass degradation, with focus on treatment of solid wastes including crop residue, paper, food, and human metabolic wastes, treatment of greywater, cabin air, off-gases from other treatment systems, and habitat condensate. This summary includes important findings from those projects, status of technology development, and recommendations for next steps. The Plant-based Anaerobic-Aerobic Bioreactor-Linked Operation (PAABLO) system was developed to reduce crop residue while generating energy and/or food. Plant residues initially were added directly to the bioreactor, and recalcitrant residue was used as a substrate for growing plants or mushrooms. Subsequently, crop residue was first pretreated with fungi to hydrolyze polymers recalcitrant to bacteria, and leachate from the fungal beds was directed to the anaerobic digester. Exoenzymes from the fungi pre-soften fibrous plant materials, improving recovery of materials that are more easily biodegraded to methane that can be used for energy reclamation. An Autothermal Thermophilic Aerobic Digestion (ATAD) system was developed for biodegradable solid wastes. Objectives were to increase water and nutrient recovery, reduce waste volume, and inactivate pathogens. Operational parameters of the reactor were optimized for degradation and resource recovery while minimizing system requirements and footprint. The start-up behavior and recycling of effluent supernatant were evaluated to maximize degradation and minimize water input. The off-gases proceeded to a bioregenerative air-treatment reactor, and the sludge effluent was investigated for multiple downstream uses including dewatering by reed beds, use as a nutrient supplement for fish or mushroom growth, and as a growth medium and nutrient source for various crops. The Bio-Regenerative Environmental Air Treatment for Health (BREATHe I) reactor treated greywater and off-gases from the thermophilic aerobic digestion reactor which contained elevated levels of ammonia (NH3 ) and hydrogen sulfide (H2 S). BREATHe I development focused initially on removing greywater contaminants with clean air supplied to a biotrickling filter. Limited removal of organic carbon (70%) led to studies indicating that biodegradation metabolites of the surfactant disodium cocoamphodiacetate are recalcitrant. Subsequent studies showed that NH3 loaded at 150 mg/min and H2 S at 0.83 mg/min were removed completely, while removal of carbonaceous compounds from greywater remained constant. A BREATHe II reactor emphasized biofilters and biotrickling filters for removal of ersatz multicomponent gaseous waste streams representative of habitat air and atmospheric condensate. The model waste stream contained a mixture of acetone, n-butanol, methane, ethylene, and ammonia. Both biofilters and biotrickling filters packed with different media were able to achieve complete removal of easily soluble compounds such as acetone, n-butanol, and ammonia within a short startup period, whereas methane was not removed because of its extreme aqueous insolubility. Different packing media and bioreactor configurations were subsequently assessed, as well as the effect of influent ammonia concentration. Research sponsored in part by NASA grant NAG5-12686.

[Research of urban eutrophic water repair by water/sediment biological bases].

PubMed

Zhou, Hui-Hua; Song, Xiao-Guang; Wu, Ge; Xie, Xin-Yuan

2013-10-01

A micro power turbine water aeration system with a water biological base and a sediment biological base was independently developed, aimed at urban water eutrophication. The results showed that the average removal rates of COD, NH+4 -N, TP by the water biological base were 82. 33% , 98. 00% and 54. 73% , respectively; The sediment reduction rate achieved by the sediment biological base could reach 20% within 5 days, and aeration in the overlying water could relieve the nutrient releasing caused by the degradation of organic matter; The effect of nutrient removal and organic matter reduction in sediment by the combined ecological restoration technology was perfect in pilot scale. The average removal rates of COD, NH+4 -N, TP were 52. 0%, 33. 6% and 23.4%, respectively, and the organic content in sediment was reduced from 38. 20% to 12.20% .

Geoengineering, marine microalgae, and climate stabilization in the 21st century

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greene, Charles H.; Huntley, Mark E.; Archibald, Ian

Society has set ambitious targets for stabilizing mean global temperature. To attain these targets, it will have to reduce CO 2 emissions to near zero by mid-century and subsequently remove CO 2 from the atmosphere during the latter half of the century. There is a recognized need to develop technologies for CO 2 removal; however, attempts to develop direct air-capture systems have faced both energetic and financial constraints. Recently, BioEnergy with Carbon Capture and Storage (BECCS) has emerged as a leading candidate for removing CO 2 from the atmosphere. But, BECCS can have negative consequences on land, nutrient, and watermore » use as well as biodiversity and food production. Here, we describe an alternative approach based on the large-scale industrial production of marine microalgae. When cultivated with proper attention to power, carbon, and nutrient sources, microalgae can be processed to produce a variety of biopetroleum products, including carbon-neutral biofuels for the transportation sector and long-lived, potentially carbon-negative construction materials for the built environment. In addition to these direct roles in mitigating and potentially reversing the effects of fossil CO 2 emissions, microalgae can also play an important indirect role. Furthermore, as microalgae exhibit much higher primary production rates than terrestrial plants, they require much less land area to produce an equivalent amount of bioenergy and/or food. On a global scale, the avoided emissions resulting from displacement of conventional agriculture may exceed the benefits of microalgae biofuels in achieving the climate stabilization goals.« less

Geoengineering, marine microalgae, and climate stabilization in the 21st century

DOE PAGES

Greene, Charles H.; Huntley, Mark E.; Archibald, Ian; ...

2017-03-21

Society has set ambitious targets for stabilizing mean global temperature. To attain these targets, it will have to reduce CO 2 emissions to near zero by mid-century and subsequently remove CO 2 from the atmosphere during the latter half of the century. There is a recognized need to develop technologies for CO 2 removal; however, attempts to develop direct air-capture systems have faced both energetic and financial constraints. Recently, BioEnergy with Carbon Capture and Storage (BECCS) has emerged as a leading candidate for removing CO 2 from the atmosphere. But, BECCS can have negative consequences on land, nutrient, and watermore » use as well as biodiversity and food production. Here, we describe an alternative approach based on the large-scale industrial production of marine microalgae. When cultivated with proper attention to power, carbon, and nutrient sources, microalgae can be processed to produce a variety of biopetroleum products, including carbon-neutral biofuels for the transportation sector and long-lived, potentially carbon-negative construction materials for the built environment. In addition to these direct roles in mitigating and potentially reversing the effects of fossil CO 2 emissions, microalgae can also play an important indirect role. Furthermore, as microalgae exhibit much higher primary production rates than terrestrial plants, they require much less land area to produce an equivalent amount of bioenergy and/or food. On a global scale, the avoided emissions resulting from displacement of conventional agriculture may exceed the benefits of microalgae biofuels in achieving the climate stabilization goals.« less

Wastewater nutrient removal in a mixed microalgae-bacteria culture: effect of light and temperature on the microalgae-bacteria competition.

PubMed

González-Camejo, J; Barat, R; Pachés, M; Murgui, M; Seco, A; Ferrer, J

2018-02-01

The aim of this study was to evaluate the effect of light intensity and temperature on nutrient removal and biomass productivity in a microalgae-bacteria culture and their effects on the microalgae-bacteria competition. Three experiments were carried out at constant temperature and various light intensities: 40, 85 and 125 µE m -2  s -1 . Other two experiments were carried out at variable temperatures: 23 ± 2°C and 28 ± 2°C at light intensity of 85 and 125 µE m -2  s -1 , respectively. The photobioreactor was fed by the effluent from an anaerobic membrane bioreactor. High nitrogen and phosphorus removal efficiencies (about 99%) were achieved under the following operating conditions: 85-125 µE m -2  s -1 and 22 ± 1°C. In the microalgae-bacteria culture studied, increasing light intensity favoured microalgae growth and limited the nitrification process. However, a non-graduated temperature increase (up to 32°C) under the light intensities studied caused the proliferation of nitrifying bacteria and the nitrite and nitrate accumulation. Hence, light intensity and temperature are key parameters in the control of the microalgae-bacteria competition. Biomass productivity significantly increased with light intensity, reaching 50.5 ± 9.6, 80.3 ± 6.5 and 94.3 ± 7.9 mgVSS L -1  d -1 for a light intensity of 40, 85 and 125 µE m -2  s -1 , respectively.

Effect of Staged Dissolved Oxygen Optimization on In-situ sludge Reduction and Enhanced Nutrient Removal in an A2MMBR-M System

NASA Astrophysics Data System (ADS)

Yang, Shan-Shan; Pang, Ji-Wei; Jin, Xiao-Man; Wu, Zhong-Yang; Yang, Xiao-Yin; Guo, Wan-Qian; Zhao, Zhi-Qing; Ren, Nan-Qi

2018-03-01

Redundant excess sludge production and considerable non-standard wastewater discharge from existing activated sludge processes are facing more and more challenges. The investigations on lower sludge production and higher sewage treatment efficiency are urgently needed. In this study, an anaerobic/anoxic/micro-aerobic/oxic-MBR combining a micro-aerobic starvation sludge holding tank (A2MMBR-M) system is developed. Batch tests on the optimization of the staged dissolved oxygen (DO) in the micro-aerobic, the first oxic, and the second oxic tanks were carried out by a 3-factor and 3-level Box-Behnken design (BBD). The optimal actual values of X1 , X2 , and X3 were DO1 of 0.3-0.5 mg/L, DO2 of 3.5-4.5 mg/L, and DO3 of 3-4 mg/L. After the optimization tests, continuous-flow experiments of anaerobic/anoxic/oxic (AAO) and A2MMBR-M systems were further conducted. Compared to AAO system, a 37.45% reduction in discharged excess sludge in A2MMBR-M system was achieved. The COD, TN, and TP removal efficiencies in A2MMBR-M system were respective 4.06%, 2.68%, and 4.04% higher than AAO system. The A2MMBR-M system is proved a promising wastewater treatment technology possessing enhanced in-situ sludge reduction and improved effluent quality. The staged optimized DO concentrations are the key controlling parameters for the realization of simultaneous in-situ sludge reduction and nutrient removal.

A hybrid constructed wetland for organic-material and nutrient removal from sewage: Process performance and multi-kinetic models.

PubMed

Nguyen, X Cuong; Chang, S Woong; Nguyen, Thi Loan; Ngo, H Hao; Kumar, Gopalakrishnan; Banu, J Rajesh; Vu, M Cuong; Le, H Sinh; Nguyen, D Duc

2018-09-15

A pilot-scale hybrid constructed wetland with vertical flow and horizontal flow in series was constructed and used to investigate organic material and nutrient removal rate constants for wastewater treatment and establish a practical predictive model for use. For this purpose, the performance of multiple parameters was statistically evaluated during the process and predictive models were suggested. The measurement of the kinetic rate constant was based on the use of the first-order derivation and Monod kinetic derivation (Monod) paired with a plug flow reactor (PFR) and a continuously stirred tank reactor (CSTR). Both the Lindeman, Merenda, and Gold (LMG) analysis and Bayesian model averaging (BMA) method were employed for identifying the relative importance of variables and their optimal multiple regression (MR). The results showed that the first-order-PFR (M 2 ) model did not fit the data (P > 0.05, and R 2  < 0.5), whereas the first-order-CSTR (M 1 ) model for the chemical oxygen demand (COD Cr ) and Monod-CSTR (M 3 ) model for the COD Cr and ammonium nitrogen (NH 4 -N) showed a high correlation with the experimental data (R 2  > 0.5). The pollutant removal rates in the case of M 1 were 0.19 m/d (COD Cr ) and those for M 3 were 25.2 g/m 2 ∙d for COD Cr and 2.63 g/m 2 ∙d for NH 4 -N. By applying a multi-variable linear regression method, the optimal empirical models were established for predicting the final effluent concentration of five days' biochemical oxygen demand (BOD 5 ) and NH 4 -N. In general, the hydraulic loading rate was considered an important variable having a high value of relative importance, which appeared in all the optimal predictive models. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhancing the Process of Anaerobic Ammonium Oxidation Coupled to Iron Reduction in Constructed Wetland Mesocosms with Supplementation of Ferric Iron Hydroxides

NASA Astrophysics Data System (ADS)

Shuai, W.; Jaffe, P. R.

2017-12-01

Effective ammonium (NH4+) removal has been a challenge in wastewater treatment processes. Aeration, which is required for the conventional NH4+ removal approach by ammonium oxidizing bacteria, is an energy intensive process during the operation of wastewater treatment plant. The efficiency of NH4+ oxidation in natural systems is also limited by oxygen transfer in water and sediments. The objective of this study is to enhance NH4+ removal by applying a novel microbial process, anaerobic NH4+ oxidation coupled to iron (Fe) reduction (also known as Feammox), in constructed wetlands (CW). Our studies have shown that an Acidimicrobiaceae bacterium named A6 can carry out the Feammox process using ferric Fe (Fe(III)) minerals like ferrihydrite as their electron acceptor. To investigate the properties of the Feammox process in CW as well as the influence of electrodes, Feammox bacterium A6 was inoculated in planted CW mesocosms with electrodes installed at multiple depths. CW mesocosms were operated using high NH4+ nutrient solution as inflow under high or low sediment Fe(III) level. During the operation, NH4+ and ferrous Fe concentration, pore water pH, voltages between electrodes, oxidation reduction potential and dissolved oxygen were measured. At the end of the experiment, CW sediment samples at different depths were taken, DNAs were extracted and quantitative polymerase chain reaction and pyrosequencing were performed to analyze the microbial communities. The results show that the high Fe level CW mesocosm has much higher NH4+ removal ability than the low Fe level CW mesocosm after Fe-reducing conditions are developed. This indicates the enhanced NH4+ removal can be attributed to elevated Feammox activity in high Fe level CW mesocosm. The microbial community structures are different in high or low Fe level CW mesocosms and on or away from the installed electrodes. The voltages between cathode and anode increased after the injection of A6 enrichment culture in low Fe level CW mesocosm but remained stable in high Fe level CW mesocosm, indicating A6 may use electrodes as their electron acceptor in the scarcity of Fe(III). The application of Feammox process in Fe-rich CW is promising in providing a cost and energy effective NH4+ removal approach, and the electrogenesis of A6 may also be useful in enhancing the Feammox process.

Effect of site treatments on soil temperature and moisture and oak and pine growth and nutrient concentrations

Treesearch

Felix, Jr. Ponder

2003-01-01

Five years after planting, measurements of soil moisture and temperature, leaf nutrient concentrations and growth, were compared for plots of northern red oak, white oak, and shortleaf pine for treatment combinations that included two levels each of harvesting intensity (organic matter removal), site disturbance (soil compaction), and weed control (control of the...

Evaluation of the effectiveness of riparian zone restoration in the southern Appalachians by assessing soil microbial populations

Treesearch

Guanglong Tian; James M. Vose; David C. Coleman; Christopher D. Geron; John T. Walker

2004-01-01

Microbial biomass, nitrifiers and denitrifiers in surface soil (0-10 cm) were quantified in a riparian zone restoration project at Coweeta, North Carolina, USA. Four treatments are included in this study: ( I ) a degraded (+N) riparian zone with continued compaction, vegetation removal, and nutrient addition (mow, roll, and nutrient addition);(2) a degraded (-N)...

Characteristics of nitrogen and phosphorus removal by a surface-flow constructed wetland for polluted river water treatment.

PubMed

Dzakpasu, Mawuli; Wang, Xiaochang; Zheng, Yucong; Ge, Yuan; Xiong, Jiaqing; Zhao, Yaqian

2015-01-01

The characteristics of nitrogen (N) and phosphorus (P) removal were studied during the 2-year operation of a free water surface flow wetland of 900 m² with hydraulic loading of 0.1 m/d to evaluate its potential to treat water from an urban stream polluted with municipal and industrial wastewater. Attention was focused on the removal of dissolved N and P by harvesting plants (local Phragmites australis and Typha orientalis) at the end of each growing season. According to findings, the removals of N and P increased from 47.1% and 17.6%, respectively, in the 1st year to 52.3% and 32.4%, respectively, in the 2nd year. Increments of N and P removal were largely attributable to plant biomass, which increased from an average dry weight of 1.77 kg/m² in the 1st year to 3.41 kg/m² in the 2nd year. The amount of nutrients assimilated by plants in the 2nd year was almost double that of the 1st year. Increasing biomass in the 2nd year also improved redox conditions in the substrate layer, which contributed to increasing the efficiency of N removal. Compared with T. orientalis, P. australis was more competitive and adapted to conditions in the wetland better; it regenerated more vigorously and contributed more to nutrient removal.

Differential Response of High-Elevation Planktonic Bacterial Community Structure and Metabolism to Experimental Nutrient Enrichment

PubMed Central

Nelson, Craig E.; Carlson, Craig A.

2011-01-01

Nutrient enrichment of high-elevation freshwater ecosystems by atmospheric deposition is increasing worldwide, and bacteria are a key conduit for the metabolism of organic matter in these oligotrophic environments. We conducted two distinct in situ microcosm experiments in a high-elevation lake (Emerald Lake, Sierra Nevada, California, USA) to evaluate responses in bacterioplankton growth, carbon utilization, and community structure to short-term enrichment by nitrate and phosphate. The first experiment, conducted just following ice-off, employed dark dilution culture to directly assess the impact of nutrients on bacterioplankton growth and consumption of terrigenous dissolved organic matter during snowmelt. The second experiment, conducted in transparent microcosms during autumn overturn, examined how bacterioplankton in unmanipulated microbial communities responded to nutrients concomitant with increasing phytoplankton-derived organic matter. In both experiments, phosphate enrichment (but not nitrate) caused significant increases in bacterioplankton growth, changed particulate organic stoichiometry, and induced shifts in bacterial community composition, including consistent declines in the relative abundance of Actinobacteria. The dark dilution culture showed a significant increase in dissolved organic carbon removal in response to phosphate enrichment. In transparent microcosms nutrient enrichment had no effect on concentrations of chlorophyll, carbon, or the fluorescence characteristics of dissolved organic matter, suggesting that bacterioplankton responses were independent of phytoplankton responses. These results demonstrate that bacterioplankton communities in unproductive high-elevation habitats can rapidly alter their taxonomic composition and metabolism in response to short-term phosphate enrichment. Our results reinforce the key role that phosphorus plays in oligotrophic lake ecosystems, clarify the nature of bacterioplankton nutrient limitation, and emphasize that evaluation of eutrophication in these habitats should incorporate heterotrophic microbial communities and processes. PMID:21483836

Anaerobic digestion for sustainable development: a natural approach.

PubMed

Gljzen, H J

2002-01-01

After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These 'natural reactors' exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic posttreatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery.

Modeling Nitrogen Processing in Northeast US River Networks

NASA Astrophysics Data System (ADS)

Whittinghill, K. A.; Stewart, R.; Mineau, M.; Wollheim, W. M.; Lammers, R. B.

2013-12-01

Due to increased nitrogen (N) pollution from anthropogenic sources, the need for aquatic ecosystem services such as N removal has also increased. River networks provide a buffering mechanism that retains or removes anthropogenic N inputs. However, the effectiveness of N removal in rivers may decline with increased loading and, consequently, excess N is eventually delivered to estuaries. We used a spatially distributed river network N removal model developed within the Framework for Aquatic Modeling in the Earth System (FrAMES) to examine the geography of N removal capacity of Northeast river systems under various land use and climate conditions. FrAMES accounts for accumulation and routing of runoff, water temperatures, and serial biogeochemical processing using reactivity derived from the Lotic Intersite Nitrogen Experiment (LINX2). Nonpoint N loading is driven by empirical relationships with land cover developed from previous research in Northeast watersheds. Point source N loading from wastewater treatment plants is estimated as a function of the population served and the volume of water discharged. We tested model results using historical USGS discharge data and N data from historical grab samples and recently initiated continuous measurements from in-situ aquatic sensors. Model results for major Northeast watersheds illustrate hot spots of ecosystem service activity (i.e. N removal) using high-resolution maps and basin profiles. As expected, N loading increases with increasing suburban or agricultural land use area. Network scale N removal is highest during summer and autumn when discharge is low and river temperatures are high. N removal as the % of N loading increases with catchment size and decreases with increasing N loading, suburban land use, or agricultural land use. Catchments experiencing the highest network scale N removal generally have N inputs (both point and non-point sources) located in lower order streams. Model results can be used to better predict nutrient loading to the coastal ocean across a broad range of current and future climate variability.

Sediments influence accumulation of two macroalgal species through novel but differing interactions with nutrients and herbivory

NASA Astrophysics Data System (ADS)

Clausing, Rachel J.; Bittick, Sarah Joy; Fong, Caitlin R.; Fong, Peggy

2016-12-01

Despite increasing concern that sediment loads from disturbed watersheds facilitate algal dominance on tropical reefs, little is known of how sediments interact with two primary drivers of algal communities, nutrients and herbivory. We examined the effects of sediment loads on the thalli of two increasingly abundant genera of macroalgae, Galaxaura and Padina, in a bay subject to terrestrial sediment influx in Mo'orea, French Polynesia. Field experiments examining (1) overall effects of ambient sediments and (2) interacting effects of sediments (ambient/removal) and herbivores (caged/uncaged) demonstrated that sediments had strong but opposite effects on both species' biomass accumulation. Sediment removal increased accumulation of Padina boryana Thivy 50% in the initial field experiment but had no effect in the second; rather, in a novel interaction, herbivores overcompensated for increases in tissue nutrient stores that occurred with sediments loads, likely by preferential consumption of nutrient-rich meristematic tissues. Despite negative effects of sediments on biomass, Padina maintained rapid growth across treatments in both experiments. In contrast, positive growth in Galaxaura divaricata Kjellman only occurred with ambient sediment loads. In mesocosm experiments testing interactions of added nutrients and sediments on growth, Galaxaura grew at equivalent rates with sediments (collected from thalli on the reef) as with additions of nitrate and phosphate, suggesting sediments provide a nutrient subsidy. For Padina, however, the only effect was a 50% reduction in growth with sediment. Overall, retention of thallus sediments creates a positive feedback that Galaxaura appears to require to sustain net growth, while Padina merely tolerates sediments. These results indicate that sediments can modify nutrient and herbivore control of algae in ways that differ among species, with the potential for strong and unexpected effects on the abundance and composition of tropical reef macroalgae.

The use of cross-linked chitosan beads for nutrients (nitrate and orthophosphate) removal from a mixture of P-PO4, N-NO2 and N-NO3.

PubMed

Jóźwiak, Tomasz; Filipkowska, Urszula; Szymczyk, Paula; Kuczajowska-Zadrożna, Małgorzata; Mielcarek, Artur

2017-11-01

A hydrogel chitosan sorbent ionically cross-linked with sodium citrate and covalently cross-linked with epichlorohydrin was used to remove nutrients from an equimolar mixture of P-PO 4 , N-NO 2 and N-NO 3 . The scope of the study included, among other things, determination of the influence of pH on nutrient sorption effectiveness, nutrient sorption kinetics as well as determination of the maximum sorption capacity of cross-linked chitosan sorbents regarding P-PO 4 (H 2 PO 4 - , HPO 4 2- ), N-NO 2 (HNO 2 , NO 2 - ), and N-NO 3 (NO 3 - ). The effect of the type of the cross-linking agent on the affinity of the modified chitosan to each nutrient was studied as well. The kinetics of nutrient sorption on the tested chitosan sorbents was best described with the pseudo-second order model. The model of intramolecular diffusion showed that P-PO 4 , N-NO 2 and N-NO3 sorption on cross-linked hydrogel chitosan beads proceeded in two phases. The best sorbent of nutrients turned out to be chitosan cross-linked covalently with epichlorohydrin; with P-PO 4 , N-NO 2 and N-NO 3 sorption capacity reaching: 1.23, 0.94 and 0.76mmol/g, respectively (total of 2.92mmol/g). For comparison, the sorption capacity of chitosan cross-linked ionically with sodium citrate was: 0.43, 0.39 and 0.39mmol/g for P-PO 4 , N-NO 2 and N-NO 3 , respectively (total of 1.21mmol/g). Copyright © 2017 Elsevier B.V. All rights reserved.

Oxygen transfer and uptake, nutrient removal, and energy footprint of parallel full-scale IFAS and activated sludge processes.

PubMed

Rosso, Diego; Lothman, Sarah E; Jeung, Matthew K; Pitt, Paul; Gellner, W James; Stone, Alan L; Howard, Don

2011-11-15

Integrated fixed-film activated sludge (IFAS) processes are becoming more popular for both secondary and sidestream treatment in wastewater facilities. These processes are a combination of biofilm reactors and activated sludge processes, achieved by introducing and retaining biofilm carrier media in activated sludge reactors. A full-scale train of three IFAS reactors equipped with AnoxKaldnes media and coarse-bubble aeration was tested using off-gas analysis. This was operated independently in parallel to an existing full-scale activated sludge process. Both processes achieved the same percent removal of COD and ammonia, despite the double oxygen demand on the IFAS reactors. In order to prevent kinetic limitations associated with DO diffusional gradients through the IFAS biofilm, this systems was operated at an elevated dissolved oxygen concentration, in line with the manufacturer's recommendation. Also, to avoid media coalescence on the reactor surface and promote biofilm contact with the substrate, high mixing requirements are specified. Therefore, the air flux in the IFAS reactors was much higher than that of the parallel activated sludge reactors. However, the standardized oxygen transfer efficiency in process water was almost same for both processes. In theory, when the oxygen transfer efficiency is the same, the air used per unit load removed should be the same. However, due to the high DO and mixing requirements, the IFAS reactors were characterized by elevated air flux and air use per unit load treated. This directly reflected in the relative energy footprint for aeration, which in this case was much higher for the IFAS system than activated sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

The precipitation of magnesium potassium phosphate hexahydrate for P and K recovery from synthetic urine.

PubMed

Xu, Kangning; Li, Jiyun; Zheng, Min; Zhang, Chi; Xie, Tao; Wang, Chengwen

2015-09-01

Nutrients recovery from urine to close the nutrient loop is one of the most attractive benefits of source separation in wastewater management. The current study presents an investigation of the thermodynamic modeling of the recovery of P and K from synthetic urine via the precipitation of magnesium potassium phosphate hexahydrate (MPP). Experimental results show that maximum recovery efficiencies of P and K reached 99% and 33%, respectively, when the precipitation process was initiated only through adding dissolvable Mg compound source. pH level and molar ratio of Mg:P were key factors determining the nutrient recovery efficiencies. Precipitation equilibrium of MPP and magnesium sodium phosphate heptahydrate (MSP) was confirmed via precipitates analysis using a Scanning Electron Microscope/Energy Dispersive Spectrometer and an X-ray Diffractometer. Then, the standard solubility products of MPP and MSP in the synthetic urine were estimated to be 10(-12.2 ± 0.0.253) and 10(-11.6 ± 0.253), respectively. The thermodynamic model formulated on chemical software PHREEQC could well fit the experimental results via comparing the simulated and measured concentrations of K and P in equilibrium. Precipitation potentials of three struvite-type compounds were calculated through thermodynamic modeling. Magnesium ammonium phosphate hexahydrate (MAP) has a much higher tendency to precipitate than MPP and MSP in normal urine while MSP was the main inhibitor of MPP in ammonium-removed urine. To optimize the K recovery, ammonium should be removed prior as much as possible and an alternative alkaline compound should be explored for pH adjustment rather than NaOH. Copyright © 2015 Elsevier Ltd. All rights reserved.

Growth characteristics and nutrient removal capability of eco-ditch plants in mesocosm sediment receiving primary domestic wastewater.

PubMed

Kumwimba, Mathieu Nsenga; Zhu, Bo; Muyembe, Diana Kavidia; Dzakpasu, Mawuli

2017-10-01

Eco-ditches are being explored to maximize their capability of capturing pollutants and mitigate any harmful side effects in rivers. In this study, mesocosm plastic drum sediment and field experiments were set up to screen 18 plant species found in ditches and identify those with potential for high biomass production and nutrients removal. Terrestrial plants grown in the mesocosm system were shown to be able to acclimate to aquatic conditions and to survive in primary domestic sewage. About 73-95% increase in plant biomass was recorded. Removal efficiencies for total nitrogen, total phosphorus, and ammonium-nitrogen from the sewage of 72-99%, 64-99%, and 75-100%, respectively, were recorded. Furthermore, complete removal of the applied nitrate-nitrogen load was achieved in mesocosm systems. Findings also show that all species, but especially Acorus calamus, Canna indica, Canna lily, Cyperus alternifolius, Colocasia gigantea, Eichhornia crassipes, Iris sibirica, and Typha latifolia had the highest efficiencies for nitrogen and phosphorous removal. The N and P mass balance analysis demonstrated that plant uptake and sediment N and P accumulation accounted for 41-86% and 18-49% of the total influent TN and TP loads, respectively. In addition, the amounts of nitrogen and phosphorous uptake by these plant species were influenced significantly by biomass. The field-culture experiment further identified Canna indica followed by Cyperus alternifolius as the most promising for high biomass production and nutrients uptake. Therefore, these plants may be recommended for extensive use in treating highly eutrophicated rivers. Outcomes of this work can be useful for model design specifications in eco-ditch mitigation of sewage pollution.

Electricity generation and nutrients removal from high-strength liquid manure by air-cathode microbial fuel cells.

PubMed

Lin, Hongjian; Wu, Xiao; Nelson, Chad; Miller, Curtis; Zhu, Jun

2016-01-01

Air-cathode microbial fuel cells (MFCs) are widely tested to recover electrical energy from waste streams containing organic matter. When high-strength wastewater, such as liquid animal manure, is used as a medium, inhibition on anode and cathode catalysts potentially impairs the effectiveness of MFC performance in power generation and pollutant removal. This study evaluated possible inhibitive effects of liquid swine manure components on MFC power generation, improved liquid manure-fed MFCs performance by pretreatment (dilution and selective adsorption), and modeled the kinetics of organic matter and nutrients removal kinetics. Parameters monitored included pH, conductivity, chemical oxygen demand (COD), volatile fatty acids (VFAs), total ammoniacal nitrogen (TAN), nitrite, nitrate, and phosphate concentrations. The removals of VFA and TAN were efficient, indicated by the short half-life times of 4.99 and 7.84 d, respectively. The mechanism for phosphate decrease was principally the salt precipitation on cathode, but the removal was incomplete after 42-d operation. MFC with an external resistor of 2.2 kΩ and fed with swine wastewater generated relatively small power (28.2 μW), energy efficiency (0.37%) and Coulombic efficiency (1.5%). Dilution of swine wastewater dramatically improved the power generation as the inhibitory effect was decreased. Zeolite and granular activated carbon were effective in the selective adsorption of ammonia or organic matter in swine wastewater, and so substantially improved the power generation, energy efficiency, and Coulombic efficiency. A smaller external resistor in the circuit was also observed to promote the organic matter degradation and thus to shorten the treatment time. Overall, air-cathode MFCs are promising for generating electrical power from livestock wastewater and meanwhile reducing the level of organic matter and nutrients.

Digestate color and light intensity affect nutrient removal and competition phenomena in a microalgal-bacterial ecosystem.

PubMed

Marcilhac, Cyril; Sialve, Bruno; Pourcher, Anne-Marie; Ziebal, Christine; Bernet, Nicolas; Béline, Fabrice

2014-11-01

During anaerobic digestion, nutrients are mineralized and may require post-treatment for optimum valorization. The cultivation of autotrophic microalgae using the digestate supernatant is a promising solution; however the dark color of the influent poses a serious problem. First, the color of the digestates was studied and the results obtained using three different digestates demonstrated a strong heterogeneity although their color remained rather constant over time. The digestates absorbed light over the whole visible spectrum and remained colored even after a ten-fold dilution. Secondly, the impact of light and of substrate color on the growth of Scenedesmus sp. and on nitrogen removal were assessed. These experiments led to the construction of a model for predicting the impact of influent color and light intensity on N removal. Maximum N removal (8.5 mgN- [Formula: see text]  L(-1) d(-1)) was observed with an initial optical density of 0.221 and 244 μmolE m(-)² s(-1) light and the model allows to determine N removal between 15.9 and 22.7 mgN- [Formula: see text]  L(-1) d(-1) in real conditions according to the dilution level of the influent and related color. Changes in the microalgae community were monitored and revealed the advantage of Chlorella over Scenedesmus under light-limitation. Additionally microalgae outcompeted nitrifying bacteria and experiments showed how microalgae become better competitors for nutrients when phosphorus is limiting. Furthermore, nitrification was limited by microalgae growth, even when P was not limiting. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of phenanthrene removal by Aspergillus niger ATC 16404 (filamentous fungi) and Pseudomonas putida KT2442 (bacteria) in enriched nutrient-liquid medium

NASA Astrophysics Data System (ADS)

Hamzah, N.; Kamil, N. A. F. M.; Singhal, N.; Padhye, L.; Swift, S.

2018-04-01

Polycyclic Aromatic Hydrocarbons (PAHs) is one of the persistent and carcinogenic pollutants that needs to be eliminated from the environment. The study on degradation of PAHs by bacteria is thoroughly discussed in literature. Many strains of bacteria were chosen in order to eliminate the PAHs compound in the environment. However, there are less study on the filamentous fungi although fungi appears to be an abundant population and as dominant group in PAHs contaminated soil habitats [1], [2]. This study was conducted to determine and compare the Phenanthrene (PHE) removal by fungi and bacteria in excessive nutrient-liquid culture. Then, the survival for both strains was investigated in the presence of PHE and finally, the analysis on the fungi-PHE interaction was carried out. In condition of excessive nutrient, the removal of PHE was evaluated for fungi and bacteria in batch experiment for 5 days. PHE removal for A.niger and P.putida were found to be 97% and 20% respectively after 5 days. The presence of PHE was negatively inhibits the grow of the bacteria and the fungus. The PHE uptake mechanism for A.niger was observed to be a passive transport mechanism with 45 μg per g fungus dry weight within 24 hr of incubation. As a conclusion, filamentous fungi have the potent role in the removal of PHE as well as bacteria but depending on the strains and the condition of the environment. Fungi is known to co-metabolize the PHE meanwhile, PHE can be used as sole carbon for bacteria. This preliminary result is significant in understanding the bacteria-fungi-PHE interaction to enhance the degradation of PAHs for co-culture study in the future.

Altered resource availability and the population dynamics of tree species in Amazonian secondary forests.

PubMed

Fortini, Lucas Berio; Bruna, Emilio M; Zarin, Daniel J; Vasconcelos, Steel S; Miranda, Izildinha S

2010-04-01

Despite research demonstrating that water and nutrient availability exert strong effects on multiple ecosystem processes in tropical forests, little is known about the effect of these factors on the demography and population dynamics of tropical trees. Over the course of 5 years, we monitored two common Amazonian secondary forest species-Lacistema pubescens and Myrcia sylvatica-in dry-season irrigation, litter-removal and control plots. We then evaluated the effects of altered water and nutrient availability on population demography and dynamics using matrix models and life table response experiments. Our results show that despite prolonged experimental manipulation of water and nutrient availability, there were nearly no consistent and unidirectional treatment effects on the demography of either species. The patterns and significance of observed treatment effects were largely dependent on cross-year variability not related to rainfall patterns, and disappeared once we pooled data across years. Furthermore, most of these transient treatment effects had little effect on population growth rates. Our results suggest that despite major experimental manipulations of water and nutrient availability-factors considered critical to the ecology of tropical pioneer tree species-autogenic light limitation appears to be the primary regulator of tree demography at early/mid successional stages. Indeed, the effects of light availability may completely override those of other factors thought to influence the successional development of Amazonian secondary forests.

Does the presence of large down wood at the time of a forest fire impact soil recovery?

DOE PAGES

Smith, Jane E.; Kluber, Laurel A.; Jennings, Tara N.; ...

2017-02-23

Fire may remove or create dead wood aboveground, but it is less clear how high severity burning of soils affects belowground microbial communities and soil processes, and for how long. Here, we investigated soil fungal and bacterial communities and biogeochemical responses of severely burned red soil and less severely burned black soil from a burned forest on the eastern slope of the Cascade Range in Oregon. We examined the effects of burn severity on soil nutrients and microbial communi- ties for 14 years after wildfire. Soil nutrients were significantly reduced in red soils. Soil fungi and bac teria, assessed withmore » molecular methods, steadily colonized both burn severities and soil biodiversity increased throughout the study showing that microbial communities seem to have the capacity to quickly adjust to extreme disturbances. Although richness did not vary by soil type, the fungal and bacterial community compositions varied with burn severity. This difference was greatest in the early time points following the fire and decreased with time. But, nutrient-limited conditions of red soils were detected for four years after the wildfire and raise concern about soil productivity at these sites.« less

Does the presence of large down wood at the time of a forest fire impact soil recovery?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jane E.; Kluber, Laurel A.; Jennings, Tara N.

Fire may remove or create dead wood aboveground, but it is less clear how high severity burning of soils affects belowground microbial communities and soil processes, and for how long. Here, we investigated soil fungal and bacterial communities and biogeochemical responses of severely burned red soil and less severely burned black soil from a burned forest on the eastern slope of the Cascade Range in Oregon. We examined the effects of burn severity on soil nutrients and microbial communi- ties for 14 years after wildfire. Soil nutrients were significantly reduced in red soils. Soil fungi and bac teria, assessed withmore » molecular methods, steadily colonized both burn severities and soil biodiversity increased throughout the study showing that microbial communities seem to have the capacity to quickly adjust to extreme disturbances. Although richness did not vary by soil type, the fungal and bacterial community compositions varied with burn severity. This difference was greatest in the early time points following the fire and decreased with time. But, nutrient-limited conditions of red soils were detected for four years after the wildfire and raise concern about soil productivity at these sites.« less

Towards the development of a novel construction solid waste (CSW) based constructed wetland system for tertiary treatment of secondary sewage effluents.

PubMed

Yang, Y; Zhang, L; Zhao, Y Q; Wang, S P; Guo, X C; Guo, Y; Wang, L; Ren, Y X; Wang, X C

2011-01-01

This study was conducted to examine the possibility of using construction solid waste (CSW), an inevitable by-product of the construction and demolition process, as the main substrate in a laboratory scale multi-stage constructed wetland system (CWs) to improve phosphorus (P) removal from secondary sewage effluent. A tidal-flow operation strategy was employed to enhance the wetland aeration. This will stimulate aerobic biological processes and benefit the organic pollutants decomposition and nitrification process for ammoniacal-nitrogen (NH(+)(4)-N) removal. The results showed that the average P concentration in the secondary sewage effluent was reduced from 1.90 mg-P/L to 0.04 mg-P/L. CSW presents excellent P removal performance. The average NH(+)(4)-N concentration was reduced from 9.94 mg-N/L to 1.0 mg-N/L through nitrification in the system. The concentration of resultant nitrite and nitrate in the effluent of the CSW based CWs ranged from 0.1 to 2.4 mg-N/L and 0.01 to 0.8 mg-N/L, respectively. The outcome of this study has shown that CSW can be successfully used to act as main substrate in CWs. The application of CSW based CWs on improving N and P removals from secondary sewage effluent presents a win-win scenario. Such the reuse of CSW will benefit both the CSW disposal and nutrient control from wastewater. More significantly, such the application can transfer the CSW from a 'waste' to 'useful' material and can ease the pressure of construction waste solid management. Meanwhile, the final effluent from the CSW-based CWs can be used as non-potable water source in landscape irrigation, agriculture and industrial process.

Total nitrogen and total phosphorus removal from brackish aquaculture wastewater using effective microorganism

NASA Astrophysics Data System (ADS)

Mohamad, K. A.; Mohd, S. Y.; Sarah, R. S.; Mohd, H. Z.; Rasyidah, A.

2017-09-01

Aquaculture is one of dominant food based industry in the world with 8.3% annual growth rate and its development had led to adverse effect on the environment. High nutrient production in form of nitrogenous compound and phosphorus contributed to environmental deterioration such as eutrophication and toxicity to the industry. Usage of Effective Microorganism (EM), one of the biological approaches to remove Total Nitrogen (TN) and Total Phosphorus (TP) in aquaculture pond was proposed. Samples were obtained from the Sea Bass intensive brackish aquaculture wastewater (AW) from fish farm at Juru, Penang and the parameters used to measure the removal of nitrogenous compounds include, pH, EM dosage, shaking, contact time and optimum variable conditions. From the study, for effective contact time, day 6 is the optimum contact time for both TN and TP with 99.74% and 62.78% removal respectively while in terms of optimum pH, the highest TN removal was at pH 7 with 66.89 %. The optimum dosage of EM is 1.5 ml with ratio 1:166 for 81.5 % TN removal was also found appropriate during the experiment. At varied optimum conditions of EM, the removal efficiency of TN and TP were 81.53% and 38.94% respectively while the removal mechanism of TN was highly dependent on the decomposition rate of specific bacteria such as Nitrobacter bacteria, Yeast and Bacillus Subtilis sp. The study has established the efficacy of EM's ability to treat excessive nutrient of TN and TP from AW.

Membrane-based processes for wastewater nutrient recovery: Technology, challenges, and future direction.

PubMed

Xie, Ming; Shon, Ho Kyong; Gray, Stephen R; Elimelech, Menachem

2016-02-01

Wastewater nutrient recovery holds promise for more sustainable water and agricultural industries. We critically review three emerging membrane processes - forward osmosis (FO), membrane distillation (MD) and electrodialysis (ED) - that can advance wastewater nutrient recovery. Challenges associated with wastewater nutrient recovery were identified. The advantages and challenges of applying FO, MD, and ED technologies to wastewater nutrient recovery are discussed, and directions for future research and development are identified. Emphasis is given to exploration of the unique mass transfer properties of these membrane processes in the context of wastewater nutrient recovery. We highlight that hybridising these membrane processes with existing nutrient precipitation process will lead to better management of and more diverse pathways for near complete nutrient recovery in wastewater treatment facilities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of phosphorus using AMD-treated lignocellulosic material

Treesearch

James S. Han; Soo-Hong Min; Yeong-Kwan Kim

2005-01-01

Excess nutrients, including phosphorus, can cause eutrophication in surface water and reservoirs. We tested the phosphate removal capacity of juniper fiber through isotherm, kinetic, column, and field tests. Heavy metals from an acid mine drainage (AMD) site were precipitated on the surface ofjuniper fiber. The modified fiber was tested in laboratory- caled batch and...