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Sample records for biological nutrient removal

  1. Biological nutrient removal from dairy wastewater

    SciTech Connect

    Danalewich, J.R.; Papagiannis, T.G.; Gerards, R.; Vriens, L.; Belyea, R.; Tumbleson, M.E.; Raskin, L.

    1998-07-01

    The authors developed a synthetic wastewater which closely represents actual milk processing wastewater. The design of this synthetic wastewater was facilitated by the collection of composite wastewater samples from 15 milk processing plants in the Upper Midwest. These samples, milk, and milk products were analyzed for various chemical parameters. Based on these results, they diluted evaporated milk and cottage cheese, as well as a number of dry chemicals to create a synthetic wastewater. The concentrations in the resulting synthetic wastewater matched average concentrations of 15 composite wastewater samples. Four continuous-flow activated sludge treatment systems are currently being operated to evaluate biological nutrient removal using this synthetic wastewater as an influent.

  2. [Study on biological nutrients removal in loop reactor].

    PubMed

    Yang, Hai-guang; Chen, Shai-lin; Li, Fei; Jiang, Tian-min; Ding, Fu-xin

    2004-01-01

    The simultaneity nitrification and denitrification (SND) was studied in a loop reactor. In the experiment, the research of biological nutrients removal was carried by changing carbon source and the method of adding carbon source, and the concentration of NOx(-)-N and the dissolved oxygen (DO) level were also inspected. The results indicated that the removal of NH4+-N could be enhanced by adding carbon source with COD 800 mg/L + 800 mg/L. And the concentration of NH4+-N in outlet was lower than 3 mg/L; Lower DO level in the reactor could be made easily by using difficultly reduced carbon source. It was useful to improve the biological nutrients removal. When using ethanol or glycerol as carbon source, the removal efficiency of NH4+-N was better than using glucose.

  3. Prefermentation of liquid dairy manure to support biological nutrient removal.

    PubMed

    Güngör, Kerem; Müftügil, Mert B; Ogejo, Jactone Arogo; Knowlton, Katharine F; Love, Nancy G

    2009-04-01

    A continuously operated, intermittently fed reactor (fermenter) system with a 2-d solids retention time was proposed for supporting biological nutrient removal from liquid dairy manure. The first objective of this study was to select a material with high fermentation potential to be used as the fermenter feed. Primary sludge, liquid separated dairy manure, and flushed dairy manure were investigated for their fermentation potential. Liquid separated dairy manure had the highest fermentation potential, 0.73mg volatile fatty acid as chemical oxygen demand/mg of initial volatile suspended solids (VSS). The second objective was to investigate the performance of a pilot-scale fermenter operated under an average organic loading rate (OLR) of 3 kg-VSS/m(3)/d. The reactor utilized 18% of the manure fermentation potential. Performance comparison of the pilot-scale fermenter and a lab-scale fermenter with an average OLR of 7 kg-VSS/m(3)/d highlighted the need to increase the OLR of the pilot-scale fermenter so that it can exploit a higher fraction of the manure fermentation potential. A continuously operated, intermittently fed fermenter with 2-d SRT can utilize the majority of the manure fermentation potential and support a downstream BNR reactor provided that it receives a sufficiently high OLR.

  4. Characteristics of Biological Nitrogen Removal in a Multiple Anoxic and Aerobic Biological Nutrient Removal Process

    PubMed Central

    Wang, Huoqing; Guan, Yuntao; Li, Li; Wu, Guangxue

    2015-01-01

    Two sequencing batch reactors, one with the conventional anoxic and aerobic (AO) process and the other with the multiple AO process, were operated to examine characteristics of biological nitrogen removal, especially of the multiple AO process. The long-term operation showed that the total nitrogen removal percentage of the multiple AO reactor was 38.7% higher than that of the AO reactor. In the multiple AO reactor, at the initial SBR cycle stage, due to the occurrence of simultaneous nitrification and denitrification, no nitrite and/or nitrate were accumulated. In the multiple AO reactor, activities of nitrite oxidizing bacteria were inhibited due to the multiple AO operating mode applied, resulting in the partial nitrification. Denitrifiers in the multiple AO reactor mainly utilized internal organic carbon for denitrification, and their activities were lower than those of denitrifiers in the AO reactor utilizing external organic carbon. PMID:26491676

  5. 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

  6. Biological nutrient removal in a sequencing batch reactor operated as oxic/anoxic/extended-idle regime.

    PubMed

    Li, Xiao-ming; Chen, Hong-bo; Yang, Qi; Wang, Dong-bo; Luo, Kun; Zeng, Guang-ming

    2014-06-01

    Previous researches have demonstrated that biological phosphorus removal from wastewater could be induced by oxic/extended-idle (O/EI) regime. In this study, an anoxic period was introduced after the aeration to realize biological nutrient removal. High nitrite accumulation ratio and polyhydroxyalkanoates biosynthesis were obtained in the aeration and biological nutrient removal could be well achieved in oxic/anoxic/extended-idle (O/A/EI) regime for the wastewater used. In addition, nitrogen and phosphorus removal performance in O/A/EI regime was compared with that in conventional anaerobic/anoxic/aerobic (A(2)/O) and O/EI processes. The results showed that O/A/EI regime exhibited higher nitrogen and phosphorus removal than A(2)/O and O/EI processes. More ammonium oxidizing bacteria and polyphosphate accumulating organisms and less glycogen accumulating organisms containing in the biomass might be the principal reason for the better nitrogen and phosphorus removal in O/A/EI regime. Furthermore, biological nutrient removal with O/A/EI regime was demonstrated with municipal wastewater. The average TN, SOP and COD removal efficiencies were 93%, 95% and 87%, respectively.

  7. Nutrient removal, microbial community and sludge settlement in anaerobic/aerobic sequencing batch reactors without enhanced biological phosphorus removal.

    PubMed

    Wu, Guangxue; Rodgers, Michael

    2010-01-01

    Nutrient removal, microbial community and sludge settlement were examined in two 3-litre laboratory-scale anaerobic/aerobic sequencing batch reactors (SBRs). One SBR was operated at 10 degrees C and the other SBR at 20 degrees C. Different from conventional enhanced biological phosphorus removal, most of the soluble sodium acetate was removed in the aerobic phase and no organic carbon uptake or biological phosphorus release occurred in the anaerobic phase. In this type of anaerobic/aerobic SBR, the phosphorus removal and sludge settlement seemed to be unstable, and the dominant microorganism was Zoogloea sp. Although no excess biological phosphorus removal occurred, extracellular phosphorus precipitation contributed a significant proportion to total phosphorus removed. Sludge volume index decreased with increasing phosphorus contents in the biomass under all conditions. The functions of extracellular polymeric substances in sludge settlement and phosphorus removal depended on the environmental conditions applied.

  8. Pilot scale study on retrofitting conventional activated sludge plant for biological nutrient removal.

    PubMed

    Chiang, W W; Qasim, S R; Zhu, G; Crosby, E C

    1999-01-01

    Eutrophication of receiving waters due to the discharge of nitrogen and phosphorus through the wastewater effluent has received much interest in recent years. Numerous techniques have been proposed and aimed at retrofitting the existing conventional activated sludge process for nutrient removal. A pilot-scale research program was conducted to evaluate the effectiveness of a biological nutrient process for this purpose. The results indicated that creating an anoxic/anaerobic zone before aeration basin significantly enhances total phosphorus (TP) and total nitrogen (TN) removal. Without internal cycle, about 80 percent TP and TN removal were respectively achieved under their optimal conditions. However, adverse trends for phosphorus and nitrogen removal were observed when the ratio of return sludge to the influent was varied in the range between 0.5 and 3.0. The total phosphorus removal decreased as the concentration of BOD5 in the mixture of influent and return sludge decreased. Improved sludge settling properties and reduced foaming problems were also observed during the pilot plant operation. Based upon experimental results, the strategies to modify an existing conventional activated sludge plant into a biological nutrient removal (BNR) system are discussed.

  9. 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.

  10. Reduction of nitrous oxide emissions from biological nutrient removal processes by thermal decomposition.

    PubMed

    Pedros, Philip B; Askari, Omid; Metghalchi, Hameed

    2016-12-01

    During the last decade municipal wastewater treatment plants have been regulated with increasingly stringent nutrient removal requirements including nitrogen. Typically biological treatment processes are employed to meet these limits. Although the nitrogen in the wastewater stream is reduced, certain steps in the biological processes allow for the release of gaseous nitrous oxide (N2O), a greenhouse gas (GHG). A comprehensive study was conducted to investigate the potential to mitigate N2O emissions from biological nutrient removal (BNR) processes by means of thermal decomposition. The study examined using the off gases from the biological process, instead of ambient air, as the oxidant gas for the combustion of biomethane. A detailed analysis was done to examine the concentration of N2O and 58 other gases that exited the combustion process. The analysis was based on the assumption that the exhaust gases were in chemical equilibrium since the residence time in the combustor is sufficiently longer than the chemical characteristics. For all inlet N2O concentrations the outlet concentrations were close to zero. Additionally, the emission of hydrogen sulfide (H2S) and ten commonly occurring volatile organic compounds (VOCs) were also examined as a means of odor control for biological secondary treatment processes or as potential emissions from an anaerobic reactor of a BNR process. The sulfur released from the H2S formed sulfur dioxide (SO2) and eight of the ten VOCs were destroyed.

  11. Enhanced biological nutrient removal in a simultaneous fermentation, denitrification and phosphate removal reactor using primary sludge as internal carbon source.

    PubMed

    Zhang, Liang; Zhang, Shujun; Wang, Shuying; Wu, Chengcheng; Chen, Yinguang; Wang, Yayi; Peng, Yongzhen

    2013-04-01

    The production of volatile fatty acids (VFAs) from primary sludge and the subsequent application to improve biological nutrient removal has drawn much attention. In this study, a novel approach of using primary sludge as an additional carbon source was conducted in batch tests. The nitritation effluent was directly injected into the sludge fermentation reactor to achieve nitrogen removal. Complete denitrification could be realized in the combined reactor. Moreover, injecting nitrite not only promoted the sludge stabilization process, but also reduced the release of phosphate and ammonium during sludge stabilization. The novel process was further evaluated in a continuous system by treating sludge dewatering liquors. Under optimum conditions, 85% removal of ammonium and 75% of total nitrogen could be obtained using primary sludge, resulting in the suitable effluent for recycling into the inlet of the wastewater treatment plant.

  12. 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.

  13. Simulation and applications of a novel modified SBR system for biological nutrient removal.

    PubMed

    Wu, W; Timpany, P; Dawson, B

    2001-01-01

    Dynamic simulation and applications of a novel, continuous-fed, constant level modified sequencing batch reactor for biological nutrient removal are presented. The underlying mathematical model and practical applications of the simulation are discussed. Case studies are presented to illustrate the applications as well as the flexibility of the system in meeting different wastewater treatment requirements. Operation experience from full-scale wastewater treatment plant demonstrates the reliability, ease of operation and high efficiency of the system. Average BOD5, total nitrogen, total phosphorus and TSS removals of 97, 81, 88 and 94% are achieved respectively on an annual basis with little operator attention. Consistently high waste activated sludge concentrations are demonstrated, averaging approximately 20,000 mg/L.

  14. 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.

  15. Biological nutrient removal in a small-scale MBR treating household wastewater.

    PubMed

    Abegglen, Christian; Ospelt, Mario; Siegrist, Hansruedi

    2008-01-01

    The biological nutrient-removal potential of an on-site Membrane bioreactor (MBR) located in the basement of a four-person house treating domestic wastewater was investigated. The reactor consists of two tanks in series. This treatment plant differs from other conventional MBRs by a highly fluctuating influent water flow and a lack of pretreatment. During the first period, the first reactor was operated as a primary clarifier, resulting in nitrogen and phosphorus removals of 50% and 25%, respectively. Primary sludge production and bad odors in the basement were further disadvantages. When using the first reactor as an anaerobic/anoxic reactor by recycling activated sludge and mixing the first reactor, nitrogen and phosphorus removals of over 90% and 70% were achieved, respectively. By applying a dynamic model of the plant, the return sludge ratio was identified as the most important parameter. With a return sludge ratio of about 1.2, optimal PAO growth and phosphorous removal up to 90% was reached. Since only activated sludge is produced with this operational mode, on-site sludge dewatering is possible. During vacation periods without loading, the Bio-P activity is kept constant if the aeration is reduced to 5-20 min d(-1).

  16. Biological Nutrient Removal Model No. 2 (BNRM2): a general model for wastewater treatment plants.

    PubMed

    Barat, R; Serralta, J; Ruano, M V; Jiménez, E; Ribes, J; Seco, A; Ferrer, J

    2013-01-01

    This paper presents the plant-wide model Biological Nutrient Removal Model No. 2 (BNRM2). Since nitrite was not considered in the BNRM1, and this previous model also failed to accurately simulate the anaerobic digestion because precipitation processes were not considered, an extension of BNRM1 has been developed. This extension comprises all the components and processes required to simulate nitrogen removal via nitrite and the formation of the solids most likely to precipitate in anaerobic digesters. The solids considered in BNRM2 are: struvite, amorphous calcium phosphate, hidroxyapatite, newberite, vivianite, strengite, variscite, and calcium carbonate. With regard to nitrogen removal via nitrite, apart from nitrite oxidizing bacteria two groups of ammonium oxidizing organisms (AOO) have been considered since different sets of kinetic parameters have been reported for the AOO present in activated sludge systems and SHARON (Single reactor system for High activity Ammonium Removal Over Nitrite) reactors. Due to the new processes considered, BNRM2 allows an accurate prediction of wastewater treatment plant performance in wider environmental and operating conditions.

  17. Demonstrating Compliance with Stringent Nitrogen Limits Using a Biological Nutrient Removal Process in California's Central Valley.

    PubMed

    Merlo, Rion; Witzgall, Bob; Yu, William; Ohlinger, Kurt; Ramberg, Steve; De Las Casas, Carla; Henneman, Seppi; Parker, Denny

    2015-12-01

    The Sacramento Regional County Sanitation District (District) must be compliant with stringent nitrogen limits by 2021 that the existing treatment facilities cannot meet. An 11-month pilot study was conducted to confirm that these limits could be met with an air activated sludge biological nutrient removal (BNR) process. The pilot BNR treated an average flow of 946 m(3)/d and demonstrated that it could reliably meet the ammonia limit, but that external carbon addition may be necessary to satisfy the nitrate limit. The BNR process performed well throughout the 11 months of operation with good settleability, minimal nocardioform content, and high quality secondary effluent. The BNR process was operated at a minimum pH of 6.4 with no noticeable impact to nitrification rates. Increased secondary sludge production was observed during rainfall events and is attributed to a change in wastewater influent characteristics.

  18. The stoichiometric ratio during biological removal of inorganic carbon and nutrient in the Mississippi River plume and adjacent continental shelf

    NASA Astrophysics Data System (ADS)

    Huang, W.-J.; Cai, W.-J.; Powell, R. T.; Lohrenz, S. E.; Wang, Y.; Jiang, L.-Q.; Hopkinson, C. S.

    2012-02-01

    The stoichiometric ratios of dissolved inorganic carbon (DIC) and nutrients during biological removal have been widely assumed to follow the Redfield ratios (especially the C/N ratio) in large river plume ecosystems. However, this assumption has not been systematically examined and documented because DIC and nutrients are rarely studied simultaneously in a river plume area, a region in which they can be affected by strong river-ocean mixing as well as intense biological activity. We examined stoichiometric ratios of DIC, total alkalinity (TA), and nutrients (NO3, PO43- and Si(OH)4) data during biological removal in the Mississippi River plume and adjacent continental shelf in June 2003 and August 2004 with biological removals defined as the difference between measured values and values predicted on the basis of conservative mixing determined using a multi-endmember mixing model. Despite complex physical and biogeochemical influences, relationships between DIC and nutrients were strongly dependent on salinity range and geographic location, and influenced by biological removal. Lower C/Si and N/Si ratios in one nearshore area were attributed to a potential silicate source induced by water exchange with coastal salt marshes. When net biological uptake was separated from river-ocean mixing and the impact of marshes and bays excluded, stoichiometric ratios of C/N/Si were similar to the Redfield ratios, thus supporting the applicability of the Redfield-type C/N/Si ratios as a principle in river-plume biogeochemical models.

  19. Benchmarking biological nutrient removal in wastewater treatment plants: influence of mathematical model assumptions.

    PubMed

    Flores-Alsina, Xavier; Gernaey, Krist V; Jeppsson, Ulf

    2012-01-01

    This paper examines the effect of different model assumptions when describing biological nutrient removal (BNR) by the activated sludge models (ASM) 1, 2d & 3. The performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) benchmark wastewater treatment plant was compared for a series of model assumptions. Three different model approaches describing BNR are considered. In the reference case, the original model implementations are used to simulate WWTP1 (ASM1 & 3) and WWTP2 (ASM2d). The second set of models includes a reactive settler, which extends the description of the non-reactive TSS sedimentation and transport in the reference case with the full set of ASM processes. Finally, the third set of models is based on including electron acceptor dependency of biomass decay rates for ASM1 (WWTP1) and ASM2d (WWTP2). The results show that incorporation of a reactive settler: (1) increases the hydrolysis of particulates; (2) increases the overall plant's denitrification efficiency by reducing the S(NOx) concentration at the bottom of the clarifier; (3) increases the oxidation of COD compounds; (4) increases X(OHO) and X(ANO) decay; and, finally, (5) increases the growth of X(PAO) and formation of X(PHA,Stor) for ASM2d, which has a major impact on the whole P removal system. Introduction of electron acceptor dependent decay leads to a substantial increase of the concentration of X(ANO), X(OHO) and X(PAO) in the bottom of the clarifier. The paper ends with a critical discussion of the influence of the different model assumptions, and emphasizes the need for a model user to understand the significant differences in simulation results that are obtained when applying different combinations of 'standard' models.

  20. 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.

  1. Application of the general model 'biological nutrient removal model no. 1' to upgrade two full-scale WWTPs.

    PubMed

    Ruano, M V; Serralta, J; Ribes, J; Garcia-Usach, F; Bouzas, A; Barat, R; Seco, A; Ferrer, J

    2012-01-01

    In this paper, two practical case studies for upgrading two wastewater treatment plants (WWTPs) using the general model BNRM 1 (Biological Nutrient Removal Model No. 1) are presented. In the first case study, the Tarragona WWTP was upgraded by reducing the phosphorus load to the anaerobic digester in order to minimize the precipitation problems. Phosphorus load reduction was accomplished by mixing the primary sludge and the secondary sludge and by elutriating the mixed sludge. In the second case study, the Alcantarilla WWTP, the nutrient removal was enhanced by maintaining a relatively low dissolved oxygen concentration in Stage A to maintain the acidogenic bacteria activity. The VFA produced in Stage A favour the denitrification process and biological phosphorus removal in Stage B. These case studies demonstrate the benefits of using the general model BNRMI to simulate settling processes and biological processes related to both anaerobic and aerobic bacteria in the same process unit.

  2. Characteristics and fate of organic nitrogen in municipal biological nutrient removal wastewater treatment plants.

    PubMed

    Czerwionka, K; Makinia, J; Pagilla, K R; Stensel, H D

    2012-05-01

    The aim of this study was to investigate the occurrence and fate of colloidal and dissolved organic nitrogen (CON and DON) across biological nutrient removal (BNR) activated sludge bioreactors. Primary and secondary effluent total nitrogen (TN) measurements and component fractionation, CON and DON concentration profiles across BNR bioreactors, and laboratory batch experiments with the process mixed liquor were carried out at several full-scale BNR plants in northern Poland. The organic nitrogen (ON) components were divided into high CON, low CON, and DON based on sequential filtration through 1.2, 0.45 and 0.1 μm pore-size filters. The average influent DON(0.1 μm) (<0.1 μm) concentrations ranged from 1.1 g N/m(3) to 3.9 g N/m(3) and accounted for only 4-13% of total organic nitrogen. In the effluents, however, this contribution increased to 12-45% (the DON(0.1 μm) concentrations varied in a narrow range of 0.5-1.3 g N/m(3)). Conversions of ON inside the bioreactors were investigated in more detail in two largest plants, i.e. Gdansk (565,000 PE) and Gdynia (516,000 PE). Inside the two studied bioreactors, the largest reductions of the colloidal fraction were found to occur in the anaerobic and anoxic compartments, whereas an increase of DON(0.1 μm) concentrations was observed under aerobic conditions in the last compartment. Batch experiments with the process mixed liquor confirmed that DON(0.1 μm) was explicitly produced in the aerobic phase and significant amounts of ON were converted in the anoxic phase of the experiments.

  3. Strategies for achieving energy neutrality in biological nutrient removal systems - a case study of the Slupsk WWTP (northern Poland).

    PubMed

    Zaborowska, Ewa; Czerwionka, Krzysztof; Makinia, Jacek

    2017-02-01

    The paper presents a model-based evaluation of technological upgrades on the energy and cost balance in a large biological nutrient removal (BNR) wastewater treatment plant (WWTP) in the city of Slupsk (northern Poland). The proposed upgrades include chemically enhanced primary sludge removal and reduction of the nitrogen load in the deammonification process employed for reject water treatment. Simulations enabled to estimate the increased biogas generation and decreased energy consumption for aeration. The proposed upgrades may lead the studied WWTP from the energy deficit to energy neutrality and positive cost balance, while still maintaining the required effluent standards for nitrogen. The operating cost balance depends on the type of applied coagulants/flocculants and specific costs of electric energy. The choice of the coagulant/flocculent was found as the main factor determining a positive cost balance.

  4. 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

  5. Assessing the effects of silver nanoparticles on biological nutrient removal in bench-scale activated sludge sequencing batch reactors.

    PubMed

    Alito, Christina L; Gunsch, Claudia K

    2014-01-21

    Consumer products such as clothing and medical products are increasingly integrating silver and silver nanoparticles (AgNPs) into base materials to serve as an antimicrobial agent. Thus, it is critical to assess the effects of AgNPs on wastewater microorganisms essential to biological nutrient removal. In the present study, pulse and continuous additions of 0.2 and 2 ppm gum arabic and citrate coated AgNPs as well as Ag as AgNO3 were fed into sequencing batch reactors (SBRs) inoculated with nitrifying sludge. Treatment efficiency (chemical oxygen demand (COD) and ammonia removal), Ag dissolution measurements, and 16S rRNA bacterial community analyses (terminal restriction fragment length polymorphism, T-RFLP) were performed to evaluate the response of the SBRs to Ag addition. Results suggest that the AgNPs may have been precipitating in the SBRs. While COD and ammonia removal decreased by as much as 30% or greater directly after spikes, SBRs were able to recover within 24 h (3 hydraulic retention times (HRTs)) and resume removal near 95%. T-RFLP results indicate Ag spiked SBRs were similar in a 16s rRNA bacterial community. The results shown in this study indicate that wastewater treatment could be impacted by Ag and AgNPs in the short term but the amount of treatment disruption will depend on the magnitude of influent Ag.

  6. 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)

  7. Two-stage thermophilic-mesophilic anaerobic digestion of waste activated sludge from a biological nutrient removal plant.

    PubMed

    Watts, S; Hamilton, G; Keller, J

    2006-01-01

    A two-stage thermophilic-mesophilic anaerobic digestion pilot-plant was operated solely on waste activated sludge (WAS) from a biological nutrient removal (BNR) plant. The first-stage thermophilic reactor (HRT 2 days) was operated at 47, 54 and 60 degrees C. The second-stage mesophilic digester (HRT 15 days) was held at a constant temperature of 36-37 degrees C. For comparison with a single-stage mesophilic process, the mesophilic digester was also operated separately with an HRT of 17 days and temperature of 36-37 degrees C. The results showed a truly thermophilic stage (60 degrees C) was essential to achieve good WAS degradation. The lower thermophilic temperatures examined did not offer advantages over single-stage mesophilic treatment in terms of COD and VS removal. At a thermophilic temperature of 60 degrees C, the plant achieved 35% VS reduction, representing a 46% increase compared to the single-stage mesophilic digester. This is a significant level of degradation which could make such a process viable in situations where there is no primary sludge generated. The fate of the biologically stored phosphorus in this BNR sludge was also investigated. Over 80% of the incoming phosphorus remained bound up with the solids and was not released into solution during the WAS digestion. Therefore only a small fraction of phosphorus would be recycled to the main treatment plant with the dewatering stream.

  8. 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

  9. Modeling external carbon addition in biological nutrient removal processes with an extension of the international water association activated sludge model.

    PubMed

    Swinarski, M; Makinia, J; Stensel, H D; Czerwionka, K; Drewnowski, J

    2012-08-01

    The aim of this study was to expand the International Water Association Activated Sludge Model No. 2d (ASM2d) to account for a newly defined readily biodegradable substrate that can be consumed by polyphosphate-accumulating organisms (PAOs) under anoxic and aerobic conditions, but not under anaerobic conditions. The model change was to add a new substrate component and process terms for its use by PAOs and other heterotrophic bacteria under anoxic and aerobic conditions. The Gdansk (Poland) wastewater treatment plant (WWTP), which has a modified University of Cape Town (MUCT) process for nutrient removal, provided field data and mixed liquor for batch tests for model evaluation. The original ASM2d was first calibrated under dynamic conditions with the results of batch tests with settled wastewater and mixed liquor, in which nitrate-uptake rates, phosphorus-release rates, and anoxic phosphorus uptake rates were followed. Model validation was conducted with data from a 96-hour measurement campaign in the full-scale WWTP. The results of similar batch tests with ethanol and fusel oil as the external carbon sources were used to adjust kinetic and stoichiometric coefficients in the expanded ASM2d. Both models were compared based on their predictions of the effect of adding supplemental carbon to the anoxic zone of an MUCT process. In comparison with the ASM2d, the new model better predicted the anoxic behaviors of carbonaceous oxygen demand, nitrate-nitrogen (NO3-N), and phosphorous (PO4-P) in batch experiments with ethanol and fusel oil. However, when simulating ethanol addition to the anoxic zone of a full-scale biological nutrient removal facility, both models predicted similar effluent NO3-N concentrations (6.6 to 6.9 g N/m3). For the particular application, effective enhanced biological phosphorus removal was predicted by both models with external carbon addition but, for the new model, the effluent PO4-P concentration was approximately one-half of that found from

  10. 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 rangeremovals, compared to those of WWTP 1, due to a greater activity of the simultaneous nitrification-denitrification processes, hydraulic retention time, and solids retention time. The compounds that were more persistent with removals below 50% in both effluents were: carbamazepine, dehydronifedipine, meprobamate, sertraline, propranolol, propoxyphene, norverapamil, diazepam, alprazolam, sulfamethoxazole, metoprolol, ofloxacin, norfloxacin, fluoxetine, erythromycin-H2O, diphenhydramine, dehydronifedipine, clarithromycin, hydrochlorothiazide, and albuterol. The application of neutral Fenton reaction as post-treatment for the two effluents from the WWTPs is promising for the removal of emerging pollutants (up to 100

  11. Filamentous Chloroflexi (green non-sulfur bacteria) are abundant in wastewater treatment processes with biological nutrient removal.

    PubMed

    Björnsson, Lovisa; Hugenholtz, Philip; Tyson, Gene W; Blackall, Linda L

    2002-08-01

    Most filamentous bacteria in biological nutrient removal (BNR) processes have not been identified beyond their morphotype and simple staining reactions. Furthermore, the majority of sludge filaments observed under the microscope do not hybridize to commonly used phylogenetic probes for well characterized bacterial phyla such as the Proteobacteria, Actinobacteria, Firmicutes and BACTEROIDETES: Specific 16S rRNA-targeted oligonucleotide probes were designed for the phylum Chloroflexi (green non-sulfur bacteria) and optimized for use in fluorescence in situ hybridization. Chloroflexi have been implicated in BNR systems by phylogenetic identification of filamentous bacteria isolated by micromanipulation from sludge and culture-independent molecular phylogenetic surveys. The predominant morphotype responding to the probes was filamentous and these filaments were generally abundant in 10 Australian full-scale and two laboratory-scale BNR samples examined. Filamentous bacteria responding to a subdivision 1 Chloroflexi probe were rare in the samples, whereas subdivision 3 Chloroflexi filaments were very common in some sludges. This is in direct contrast to results obtained from molecular phylogenetic surveys of BNR systems where most sludge 16S rDNA clones belong to subdivision 1 and only a few to subdivision 3. It is suggested that filamentous bacteria belonging to the Chloroflexi phylum account for a large fraction of phylogenetically uncharacterized filaments in BNR systems and are likely to be abundant in such systems on a global scale.

  12. Modeling the Effect of External Carbon Source Addition under Different Electron Acceptor Conditions in Biological Nutrient Removal Activated Sludge Systems.

    PubMed

    Hu, Xiang; Wisniewski, Kamil; Czerwionka, Krzysztof; Zhou, Qi; Xie, Li; Makinia, Jacek

    2016-02-16

    The aim of this study was to expand the International Water Association Activated Sludge Model No. 2d (ASM2d) to predict the aerobic/anoxic behavior of polyphosphate accumulating organisms (PAOs) and "ordinary" heterotrophs in the presence of different external carbon sources and electron acceptors. The following new aspects were considered: (1) a new type of the readily biodegradable substrate, not available for the anaerobic activity of PAOs, (2) nitrite as an electron acceptor, and (3) acclimation of "ordinary" heterotrophs to the new external substrate via enzyme synthesis. The expanded model incorporated 30 new or modified process rate equations. The model was evaluated against data from several, especially designed laboratory experiments which focused on the combined effects of different types of external carbon sources (acetate, ethanol and fusel oil) and electron acceptors (dissolved oxygen, nitrate and nitrite) on the behavior of PAOs and "ordinary" heterotrophs. With the proposed expansions, it was possible to improve some deficiencies of the ASM2d in predicting the behavior of biological nutrient removal (BNR) systems with the addition of external carbon sources, including the effect of acclimation to the new carbon source.

  13. Evaluation of biological nutrient removal from wastewater by Twin Circulating Fluidized Bed Bioreactor (TCFBBR) using a predictive fluidization model and AQUIFAS APP.

    PubMed

    Andalib, Mehran; Nakhla, George; Sen, Dipankar; Zhu, Jesse

    2011-02-01

    A two-phase and three-phase predictive fluidization model based on the characteristics of a system such as media type and size, flow rates, and reactor cross sectional area was proposed to calculate bed expansion, solid, liquid and gas hold up and specific surface area (SSA) of the biofilm particles. The model was subsequently linked to 1d AQUIFAS APP software (Aquaregen) to model biological nutrient removal in two phase (anoxic) and three phase (aerobic) fluidized bed bioreactors. The credibility of the proposed model for biological nutrient removal was investigated using the experimental data from a Twin Circulating Fluidized Bed Bioreactors (TCFBBR) treating synthetic and municipal wastewater. The SSA of bio-particles and volume of the expanded bed were simulated as a function of operational parameters. Two-sided t-tests demonstrated that simulated SCOD, NH(4)-N, NO(3)-N, TN, VSS and biomass yields agreed with the experimental values at the 95% confidence level.

  14. 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.

  15. Outcomes of a 2-year investigation on enhanced biological nutrients removal and trace organics elimination in membrane bioreactor (MBR).

    PubMed

    Lesjean, B; Gnirss, R; Buisson, H; Keller, S; Tazi-Pain, A; Luck, F

    2005-01-01

    Two configurations of membrane bioreactors were identified to achieve enhanced biological phosphorus and nitrogen removal, and assessed over more than two years with two parallel pilot plants of 2m3 each. Both configurations included an anaerobic zone ahead of the biological reactor, and differed by the position of the anoxic zone: standard pre-denitrification, or post-denitrification without dosing of carbon source. Both configurations achieved improved phosphorus removal. The goal of 50 microgP/L in the effluent could be consistently achieved with two types of municipal wastewater, the second site requiring a low dose of ferric salt ferric salt < 3 mgFe/L. The full potential of biological phosphorus removal could be demonstrated during phosphate spiking trials, where up to 1 mg of phosphorus was biologically eliminated for 10 mg BOD5 in the influent. The post-denitrification configuration enabled a very good elimination of nitrogen. Daily nitrate concentration as low as 1 mgN/L could be monitored in the effluent in some periods. The denitrification rates, greater than those expected for endogenous denitrification, could be accounted for by the use of the glycogene pool, internally stored by the denitrifying microorganisms in the anaerobic zone. Pharmaceuticals residues and steroids were regularly monitored on the two parallel MBR pilot plants during the length of the trials, and compared with the performance of the Berlin-Ruhleben WWTP. Although some compounds such as carbamazepine were persistent through all the systems, most of the compounds could be better removed by the MBR plants. The influence of temperature, sludge age and compound concentration could be shown, as well as the significance of biological mechanisms in the removal of trace organic compounds.

  16. 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.

  17. Long-term effects of copper nanoparticles on wastewater biological nutrient removal and N2O generation in the activated sludge process.

    PubMed

    Chen, Yinguang; Wang, Dongbo; Zhu, Xiaoyu; Zheng, Xiong; Feng, Leiyu

    2012-11-20

    The increasing use of copper nanoparticles (Cu NPs) raises concerns about their potential toxic effects on the environment. However, their influences on wastewater biological nutrient removal (BNR) and nitrous oxide (N(2)O) generation in the activated sludge process have never been documented. In this study the long-term effects of Cu NPs (0.1-10 mg/L) on BNR and N(2)O generation were investigated. The total nitrogen (TN) removal was enhanced and N(2)O generation was reduced at any Cu NPs levels investigated, but both ammonia and phosphorus removals were not affected. The mechanism studies showed although most of the Cu NPs were absorbed to activated sludge, the activated sludge surface was not damaged, and the released copper ion from Cu NPs dissolution was the main reason for TN removal improvement and N(2)O reduction. It was also found that the transformation of polyhydroxyalkanoates and the activities of ammonia monooxygenase, nitrite oxidoreductase, exopolyphosphatase, and polyphosphate kinase were not affected by Cu NPs, whereas the decreased metabolism of glycogen and the increased activities of denitrification enzymes were observed. Further investigation revealed that Cu NPs increased the number of denitrifiers (especially N(2)O reducing denitrifiers) but decreased nitrite accumulation. All these observations were in correspondence with the enhancement of TN removal and reduction of N(2)O generation.

  18. The variation of volatile fatty acid compositions in sewer length, and its effect on the process design of biological nutrient removal.

    PubMed

    Yun, Z; Yun, G H; Lee, H S; Yoo, T U

    2013-01-01

    The potential of enhanced biological phosphorus removal (EBPR) in biological nutrient removal (BNR) systems critically depends on the availability and types of volatile fatty acids (VFAs) in sewage. Although the characteristics of VFAs in sewage are strongly related with the biochemical transformations in the sewer system, they have not been studied thoroughly in terms of BNR process design. We have investigated the characteristics of VFAs in influent of nine sewage treatment plants which represent typical small to very large sewer systems in Korea. We found that influent total VFACOD (VFA as chemical oxygen demand) concentrations ranged from 20.4 to 65.2 mg/L. Acetic acid was a predominant VFA in sewage, and the propionic acid (HPr) portion averaged 38.7% of total VFACOD. However the sewage from longer sewer systems showed more HPr content, indicating that type of VFA varied with the total sewer length. The finding is a particularly important consideration for BNR process design since availability of HPr positively behaved to suppress the unfavorable growth of glycogen-accumulating organisms. The implication of these findings for BNR process design is discussed in this paper.

  19. Simultaneous nitrogen and phosphorus recovery from sludge-fermentation liquid mixture and application of the fermentation liquid to enhance municipal wastewater biological nutrient removal.

    PubMed

    Zhang, Chao; Chen, Yinguang

    2009-08-15

    Recently, waste activated sludge (WAS) fermentation for short-chain fatty acids (SCFAs) production has drawn much attention because the waste biosolids produced in wastewater treatment plants (WWTP) can be reused, and the produced SCFAs can be applied to promote biological nutrient removal (BNR). Usually, after WAS fermentation, the fermentation liquid is separated and then the recovery of ammonium and phosphorus, which are released during WAS fermentation, is conducted to prevent the increase of nitrogen and phosphorus loadings to WWTP. As an alternative to the traditional process, this paper investigated the recovery of ammonium and phosphorus in the formation of struvite before sludge-liquid separation, and its positive effecton the following sludge-liquid filtration separation. First, the conditions for ammonium and phosphorus recovery from the WAS fermentation mixture were optimized by response surface methodology (RSM). Then, the effect of ammonium and phosphorus recovery on sludge filtration dewatering was investigated. With ammonium and phosphorus recovery, it was observed that the specific resistance to filtration (SRF), the capillary suction time (CST), and the sludge volume after filtration reduced by 96.9, 99.6, and 88.7%, respectively, compared with no ammonium and phosphorus recovered sludge. Third, the mechanisms for ammonium and phosphorus recovery significantly enhancing sludge dewatering capacity were investigated. The formation of struvite, the neutralization of 5 potential, the increase of magnesium ion, which was added during ammonium and phosphorus recovery, and the decrease of sludge polymeric substance caused the improvement of sludge dewatering. Finally, the fermentation liquid was used as the additional carbon source of BNR, and the nutrient removal efficiency was obviously enhanced.

  20. Nutrients removal and recovery in bioelectrochemical systems: a review.

    PubMed

    Kelly, Patrick T; He, Zhen

    2014-02-01

    Nutrient removal and recovery has received less attention during the development of bioelectrochemical systems (BES) for energy efficient wastewater treatment, but it is a critical issue for sustainable wastewater treatment. Both nitrogen and phosphorus can be removed and/or recovered in a BES through involving biological processes such as nitrification and bioelectrochemical denitrification, the NH4(+)/NH3 couple affected by the electrolyte pH, or precipitating phosphorus compounds in the high-pH zone adjacent a cathode electrode. This paper has reviewed the nutrients removal and recovery in various BES including microbial fuel cells and microbial electrolysis cells, discussed the influence factors and potential problems, and identified the key challenges for nitrogen and phosphorus removal/recovery in a BES. It expects to give an informative overview of the current development, and to encourage more thinking and investigation towards further development of efficient processes for nutrient removal and recovery in a BES.

  1. Biological nutrient and organic removal from meat packing wastewater with a unique sequence of suspended growth and fixed-film reactors.

    PubMed

    Lim, S J; Kim, S H; Fox, P

    2009-01-01

    A unique sequence of anaerobic filter/suspended anaerobic/aerobic (AO) reactor/aerobic filter system was developed to alleviate the drawbacks of conventional suspended growth and fixed growth systems. An anaerobic filter (AF) was used to efficiently produce volatile fatty acids (VFAs) prior to the aerobic suspended growth. A second anaerobic reactor was installed in the A/O return activated sludge line to improve phosphorus uptake by potentially controlling glycogen accumulating organisms (GAOs). One biological aerobic filter (BAF) was used for nitrification followed by an anoxic filter for denitrification and a second BAF was used for effluent polishing. The meat packing wastewater had a biochemical oxygen demand (BOD) of 853 mg/L and total nitrogen (T-N) and total phosphorus (T-P) concentrations of 61.1 mg/L and 5.8 mg/L, respectively. The BOD removal efficiency was 99.0-99.7% and the suspended solids (SS) concentration in the effluent was below 10 mg/L. The T-N removal efficiency was maintained at greater than 75.0% except at low C/N ratios. A high T-P removal efficiency, 74.7-83.9%, was also obtained when the system was operated at a hydraulic retention time of 15.7 hrs. The AF successfully produced VFAs that aided in phosphorus removal. Additionally, recycled concrete aggregate used as attachment media in the biological filters continuously provided micronutrients and stabilized the pH.

  2. 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

  3. Biomass fermentation to augment biological phosphorus removal.

    PubMed

    Yuan, Q; Oleszkiewicz, J A

    2010-01-01

    A combination of a lab scale biological phosphorus removal sequencing batch reactor (called mother reactor) and a side-stream biomass fermenter was setup. It was found that when fermented biomass was recirculated back into the mother reactor as volatile fatty acid (VFA) supplement, the phosphate concentration in the effluent decreased from 6 in the control reactor to 4.5 mgL(-1) in the effluent from mother reactor. The addition of the fermentation effluent into the mother reactor increased the phosphate and ammonium loads and resulted in deterioration of nitrification. Phosphorus removal and nitrification improved when the fermented biomass was separated from the liquid phase using an up-flow system, followed by the addition of MgO to the supernatant to precipitate phosphate and ammonium. Phosphorus removal was further improved by delaying the time of VFA addition into mother reactor during the anaerobic period as soon as denitrification ceased. Biomass fermentation was found to generate 157 mg VFA-COD by fermenting 1g of biomass at a solids retention time of 5d. Acetate (78% of generated COD) and propionic acid (10%) were the major components of the produced VFA. It was concluded that biomass fermentation to augment a biological nutrient removal process can be effective if generated phosphate and ammonia are removed, e.g. through struvite precipitation.

  4. Microbial evaluation of activated sludge and filamentous population at eight Czech nutrient removal activated sludge plants during year 2000.

    PubMed

    Krhutková, O; Ruzicková, I; Wanner, J

    2002-01-01

    The long-term project on the survey of filamentous microorganisms, which started in 1996, was finished in 2000 by the survey of eight Czech activated sludge plants with biological nutrient removal (BNR) systems. At all plants with enhanced biological nutrient removal, specific microbial population (mostly from the point of view of filaments occurrence), operational problems (presence of biological foaming, bulking) and plant operation were observed periodically and longer than 1 year. In our paper the relationship between the composition of activated sludge (especially filaments) consortia and modification of the process with nutrient removal is discussed. At the surveyed plants Type 0092 and Microthrix parvicella were identified as dominant Eikelboom filamentous types.

  5. Nutrient removal by prairie filter strips in agricultural landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen and phosphorus from agricultural landscapes have been identified as a primary source of excess nutrients in aquatic systems. The primary objective of this study was to evaluate the effectiveness of prairie filter strips (PFS) in removing nutrients from cropland runoff in 12 small watersheds...

  6. Optimizing Nutrient Uptake in Biological Transport Networks

    NASA Astrophysics Data System (ADS)

    Ronellenfitsch, Henrik; Katifori, Eleni

    2013-03-01

    Many biological systems employ complex networks of vascular tubes to facilitate transport of solute nutrients, examples include the vascular system of plants (phloem), some fungi, and the slime-mold Physarum. It is believed that such networks are optimized through evolution for carrying out their designated task. We propose a set of hydrodynamic governing equations for solute transport in a complex network, and obtain the optimal network architecture for various classes of optimizing functionals. We finally discuss the topological properties and statistical mechanics of the resulting complex networks, and examine correspondence of the obtained networks to those found in actual biological systems.

  7. Nutrient enrichment and fish nutrient tolerance: Assessing biologically relevant nutrient criteria

    USGS Publications Warehouse

    Meador, Michael R.

    2013-01-01

    Relationships between nutrient concentrations and fish nutrient tolerance were assessed relative to established nutrient criteria. Fish community, nitrate plus nitrite (nitrate), and total phosphorus (TP) data were collected during summer low-flow periods in 2003 and 2004 at stream sites along a nutrient-enrichment gradient in an agricultural basin in Indiana and Ohio and an urban basin in the Atlanta, Georgia, area. Tolerance indicator values for nitrate and TP were assigned for each species and averaged separately for fish communities at each site (TIVo). Models were used to predict fish species expected to occur at a site under minimally disturbed conditions and average tolerance indicator values were determined for nitrate and TP separately for expected communities (TIVe). In both areas, tolerance scores (TIVo/TIVe) for nitrate increased significantly with increased nitrate concentrations whereas no significant relationships were detected between TP tolerance scores and TP concentrations. A 0% increase in the tolerance score (TIVo/TIVe = 1) for nitrate corresponded to a nitrate concentration of 0.19 mg/l (compared with a USEPA summer nitrate criterion of 0.17 mg/l) in the urban area and 0.31 mg/l (compared with a USEPA summer nitrate criterion of 0.86 mg/l) in the agricultural area. Fish nutrient tolerance values offer the ability to evaluate nutrient enrichment based on a quantitative approach that can provide insights into biologically relevant nutrient criteria.

  8. Striking the balance between nutrient removal, greenhouse gas emissions, receiving water quality, and costs.

    PubMed

    Falk, Michael W; Reardon, David J; Neethling, J B; Clark, David L; Pramanik, Amit

    2013-12-01

    This Water Environment Research Foundation study considered the relationship between varying nutrient-removal levels at wastewater treatment plants, greenhouse gas emissions, receiving water quality (measured by potential algal production), and costs. The effluent nutrient concentrations required by some U.S. permits are very low, approaching the technology-best-achievable performance. This study evaluated five different treatment levels at a nominal 40 ML/d (10 mgd) flow. Greenhouse gas emissions and costs increase gradually up to the technologies' best-achievable performance, after which they increase exponentially. The gradual increase is attributed to additional biological treatment facilities, increased energy and chemical use, and additional tertiary nitrogen and phosphorus removal processes. Within the limited focus of this study, the evaluation shows that a point of diminishing return is reached as nutrient-removal objectives approach the technology-best-achievable performance, where greenhouse gas emissions and cost of treatment increases rapidly while the potential for algal growth reduce marginally.

  9. Nutrient removal from swine lagoon effluent by duckweed

    SciTech Connect

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

    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{sub 4}-P, TOC, K, Cu, and Zn were 83, 100, 49, 31, 68, 21, 28 and 67%.

  10. Solids and nutrient removal from flushed swine manure using polyacrylamides

    SciTech Connect

    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 performance 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

  11. 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.

  12. Enhancing biological phosphorus removal with glycerol.

    PubMed

    Yuan, Q; Sparling, R; Lagasse, P; Lee, Y M; Taniguchi, D; Oleszkiewicz, J A

    2010-01-01

    An enhanced biological phosphorus removal process (EBPR) was successfully operated in presence of acetate. When glycerol was substituted for acetate in the feed the EBPR process failed. Subsequently waste activated sludge (WAS) from the reactor was removed to an off-line fermenter. The same amount of glycerol was added to the WAS fermenter which led to significant volatile fatty acids (VFA) production. By supplying the system with the VFA-enriched supernatant of the fermentate, biological phosphorus removal was enhanced. It was concluded that, if glycerol was to be used as an external carbon source in EBPR, the effective approach was to ferment glycerol with waste activated sludge.

  13. Enhanced biological phosphorus removal and recovery.

    PubMed

    Machnicka, Alicja; Grubel, Klaudiusz; Suschka, Jan

    2008-07-01

    Activated sludge systems designed for enhanced nutrient removal are based on the principle of altering anaerobic and aerobic conditions for growth of microorganisms with a high capacity of phosphorus accumulation. Most often, filamentous bacteria constitute a component of the activated sludge microflora. The filamentous microorganisms are responsible for foam formation and activated sludge bulking. The results obtained confirm unanimously that the filamentous bacteria have the ability of phosphorus uptake and accumulation as polyphosphates. Hydrodynamic disintegration of the foam microorganisms results in the transfer of phosphorus and metal cations and ammonium-nitrogen into the liquid phase. It was demonstrated that the disintegration of foam permits the removal of a portion of the nutrients in the form of struvite.

  14. 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...

  15. Development of Effects-Based Nutrient Criteria using Biological Endpoints

    NASA Astrophysics Data System (ADS)

    Miltner, R.

    2005-05-01

    Ohio employs biological endpoints to judge the status of aquatic life in rivers and streams. Specifically, numeric criteria derived from biological indices have been incorporated into Ohio's water quality standards for fish and macroinvertebrate communities. When appropriate, chemical-specific water quality standards derived from dose-response curves are used in concert with the biological indices to ascribe the causes and sources of impairment to polluted streams. However, water quality criteria have not been established for all polluting agents, especially those, like nutrients, that do not elicit a simple dose-response curve. In such cases, where biological impairment is observed, the linkage between the impairment and causal agent is made inferentially. Ohio EPA is currently studying the relationship between nutrient concentrations, periphytic chlorophyll a concentrations, and biological indices to ascertain whether a direct relationship exists between nutrient concentration and the biological health of fish and macroinvertebrate communities, with the eventual goal of adopting effects-based nutrient criteria in Ohio's water quality standards. Results from the first field season show a strong relationship between chlorophyll a concentrations, and physical and land use variables. Additionally, 48 h dissolved oxygen flux correlated with periphytic chlorophyll a concentrations and the degree of canopy cover.

  16. Method and apparatus for determining nutrient stimulation of biological processes

    DOEpatents

    Colwell, Frederick S.; Geesey, Gill G.; Gillis, Richard J.; Lehman, R. Michael

    1997-01-01

    A method and apparatus for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for said microorganisms in said sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure differences in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses.

  17. Method and apparatus for determining nutrient stimulation of biological processes

    DOEpatents

    Colwell, F.S.; Geesey, G.G.; Gillis, R.J.; Lehman, R.M.

    1997-11-11

    A method and apparatus is described for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for said microorganisms in said sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure differences in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses. 5 figs.

  18. Method and apparatus for determining nutrient stimulation of biological processes

    DOEpatents

    Colwell, Frederick S.; Geesey, Gill G.; Gillis, Richard J.; Lehman, R. Michael

    1999-01-01

    A method and apparatus for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for said microorganisms in said sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure difference in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses.

  19. Method and apparatus for determining nutrient stimulation of biological processes

    DOEpatents

    Colwell, F.S.; Geesey, G.G.; Gillis, R.J.; Lehman, R.M.

    1999-07-13

    A method and apparatus are disclosed for determining the nutrients to stimulate microorganisms in a particular environment. A representative sample of microorganisms from a particular environment are contacted with multiple support means wherein each support means has intimately associated with the surface of the support means a different nutrient composition for microorganisms in the sample. The multiple support means is allowed to remain in contact with the microorganisms in the sample for a time period sufficient to measure difference in microorganism effects for the multiple support means. Microorganism effects for the multiple support means are then measured and compared. The invention is particularly adaptable to being conducted in situ. The additional steps of regulating nutrients added to the particular environment of microorganisms can enhance the desired results. Biological systems particularly suitable for this invention are bioremediation, biologically enhanced oil recovery, biological leaching of metals, and agricultural bioprocesses. 5 figs.

  20. Enhanced biological phosphorus removal employing EDTA disodium

    SciTech Connect

    Bojinova, D.; Velkova, R.

    1996-12-31

    The biological phosphorus removal is a promising alternative to the conventional chemical technologies for processing of phosphate raw materials. The object of this study was the effect of EDTA disodium on the biotreatment of tunisian phosphorite with the strain of Aspergillus niger. The incubation was carried out in two nutritive mediums, with different phosphate content. The experimental results showed that the additives of EDTA disodium in the nutritive medium increased the rate of extraction of P{sub 2}O{sub 5} and shortened significantly the time for biological leaching. 5 refs., 3 figs., 2 tabs.

  1. [Biological phosphorus removal in intermittent aerated biological filter].

    PubMed

    Zeng, Long-Yun; Yang, Chun-Ping; Guo, Jun-Yuan; Luo, Sheng-Lian

    2012-01-01

    Under intermittent aerated and continuous fed operation where the biofilm system was subjected to alternated anaerobic/aerobic condition, the effect of influent volatile fatty acids (VFAs) concentrations, operation cycle and backwash on the biological phosphorus removal performance of the biofilter was studied. In the experiment, synthetic domestic wastewater was used, and the influent velocity was 5 L x h(-1) with gas versus liquid ratio of 8:1 and hydraulic retention time (HRT) of 1.3 h, resulting in average COD, ammonium and phosphorus load of 4.7, 0.41 and 0.095 g x (L x d) (-1) respectively. Results show that, (1) effective release and uptake of phosphorus was achieved in a operation cycle; (2) when influent VFAs was 100 mg x L(-1) (calculated by COD value) and operation cycle was 6 h the filter performed best in phosphorus removal, the phosphorus loading removal rate can be as much as 0.059 g x (L x d)(-1) at the aerated phase with those of COD and ammonium being 3.8 g x (L x d)(-1) and 0.28 g x (L x d)(-1) respectively, and with average effluent phosphorus, COD and ammonium concentrations being 1.8, 43.6 and 8.7 mg x L(-1), which shows nitrogen loss also happened; (3) the pause of backwash decreased the phosphorus removal performance rapidly with the removal efficiency lower than 40% in two days, but the consequent daily backwash operation gave a short improvement on the phosphorus removal, which disappeared in another two days. Thus, it is shown that biological phosphorus removal achieved with better phosphorus loading removal performance in the biofilter under intermittent aerated and continuous fed operation, and that sufficient and stable influent VFAs concentration, proper operation cycle, and more frequent backwash favored the performance.

  2. The micro and macro of nutrients across biological scales.

    PubMed

    Warne, Robin W

    2014-11-01

    During the past decade, we have gained new insights into the profound effects that essential micronutrients and macronutrients have on biological processes ranging from cellular function, to whole-organism performance, to dynamics in ecological communities, as well as to the structure and function of ecosystems. For example, disparities between intake and organismal requirements for specific nutrients are known to strongly affect animal physiological performance and impose trade-offs in the allocations of resources. However, recent findings have demonstrated that life-history allocation trade-offs and even microevolutionary dynamics may often be a result of molecular-level constraints on nutrient and metabolic processing, in which limiting reactants are routed among competing biochemical pathways. In addition, recent work has shown that complex ecological interactions between organismal physiological states such as exposure to environmental stressors and infectious pathogens can alter organismal requirements for, and, processing of, nutrients, and even alter subsequent nutrient cycling in ecosystems. Furthermore, new research is showing that such interactions, coupled with evolutionary and biogeographical constraints on the biosynthesis and availability of essential nutrients and micronutrients play an important, but still under-studied role in the structuring and functioning of ecosystems. The purpose of this introduction to the symposium "The Micro and Macro of Nutrient Effects in Animal Physiology and Ecology" is to briefly review and highlight recent research that has dramatically advanced our understanding of how nutrients in their varied forms profoundly affect and shape ecological and evolutionary processes.

  3. 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.

  4. Biomass production and nutrient removal by switchgrass under irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  5. Phosphorus removal and recovery from domestic wastewater in a novel process of enhanced biological phosphorus removal coupled with crystallization.

    PubMed

    Zou, Haiming; Wang, Yan

    2016-07-01

    A new process of enhanced biological phosphorus removal coupled with crystallization recovery of phosphorus was developed here, where the feasibility of nutrients removal and potential for phosphorus recovery from domestic wastewater was further assessed. Results showed that an excellent nutrients removal and phosphorus recovery performance was achieved, in which the averaged COD, PO4(3-)-P and NO3(-)-N removal efficiencies were 82.6%, 87.5% and 91.6%, respectively and a total of 59.3% of phosphorus was recovered as hydroxyapatite. What's more, crystallization recovery of phosphorus greatly enhanced the biological phosphorus removal efficiency. After the incorporation of the phosphorus recovery column via side-stream, the phosphorus concentration of effluent was significantly decreased ranging from 1.24mg/L to 0.85mg/L, 0.52mg/L and 0.41mg/L at the lateral flow ratios of 0, 0.1, 0.2 and 0.3, respectively. The results obtained here would be beneficial to provide a prospective alternative for phosphorus removal and recovery from wastewater.

  6. 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.

  7. Nutrient Recovery of Plant Leachates Under Thermal, Biological, and Photocatalytic Pretreatments

    NASA Technical Reports Server (NTRS)

    Wong, Les

    2015-01-01

    Nutrient recovery has always been a problem for long distance and long-term space missions. To allow humans to man these missions, a steady source of oxygen, water, and food are necessary for survival beyond Earth's atmosphere. Plants are currently an area of interest since they are capable of providing all three resources for life sustainability. We are currently interested in nutrient recovery for future plant growth and simple aqueous leachate extractions can recover some of the nutrients. However, leaching plants also removes water-soluble organic plant wastes, which inhibits plant growth if not separated properly. To combat the issues with waste and maximize nutrient recovery, we are attempting to pre-treat the plant matter using biological, thermal, and photocatalytic methods before subjecting the solution with variable-strength acid digestion. For the biological method, the inoculums: mixed heterotrophic/nitrifying bioreactor effluent and Trichoderma vessei are used in an attempt to liberate more nutrients from the plant matter. For the thermal method, plants are subjected to varying temperatures at different retention times to determine nutrient recovery. Lastly, the photocatalytic method utilizes TiO (sub 2)'s oxidizing abilities under specific pHs and retention times to reduce organic wastes and improve nutrient gains. A final acid digestion serves to liberate nutrients even further in order to maximize recovery. So far, we have tested ideal acid digestion variables for practicality and performance in our experiments. We found that a low retention time of 10 minutes and a high acid concentration of 0.1 and 1 mole HCl were the most effective at nutrient recovery. For space travel purposes, 0.1 mole currently looks like a viable acid digestion to use since it is relatively effective and sustainable from a mass and energy balance if acid recovery can be performed on waste brines. Biological pretreatments do not look to be too effective and the thermal and

  8. Hydrologic and biologic influences on stream network nutrient concentrations: Interactions of hydrologic turnover and concentration-dependent nutrient uptake

    NASA Astrophysics Data System (ADS)

    Mallard, J. M.; McGlynn, B. L.; Covino, T. P.; Bergstrom, A.

    2012-12-01

    Stream networks lie in a crucial landscape position between terrestrial ecosystems and downstream water bodies. As such, whether inferring terrestrial watershed processes from watershed outlet nutrient signals or predicting the effect of observed terrestrial processes on stream nutrient signals, it is requisite to understand how stream networks can modulate terrestrial nutrient inputs. To date integrated understanding and modeling of physical and biological influences on nutrient concentrations at the stream network scale have been limited. However, watershed scale groundwater - surface water exchange (hydrologic turnover), concentration-variable biological uptake, and the interaction between the two can strongly modify stream water nutrient concentrations. Stream water and associated nutrients are lost to and replaced from groundwater with a distinct nutrient concentrations while in-stream nutrients can also be retained by biological processes at rates that vary with concentration. We developed an empirically based network scale model to simulate the interaction between hydrologic turnover and concentration-dependent nutrient uptake across stream networks. Exchange and uptake parameters were measured using conservative and nutrient tracer addition experiments in the Bull Trout Watershed, central Idaho. We found that the interaction of hydrologic turnover and concentration-dependent uptake combined to modify and subsequently stabilize in-stream concentrations, with specific concentrations dependent on the magnitude of hydrologic turnover, groundwater concentrations, and the shape of nutrient uptake kinetic curves. We additionally found that by varying these physical and biological parameters within measured ranges we were able to generate a spectrum of stream network concentration distributions representing a continuum of shifting magnitudes of physical and biological influences on in-stream concentrations. These findings elucidate the important and variable role

  9. Hydrologic and biologic influences on stream network nutrient concentrations: Interactions of hydrologic turnover and concentration-dependent nutrient uptake

    NASA Astrophysics Data System (ADS)

    Mallard, John; McGlynn, Brian; Covino, Tim

    2016-04-01

    Stream networks lie in a crucial landscape position between terrestrial ecosystems and downstream water bodies. As such, whether inferring terrestrial watershed processes from watershed outlet nutrient signals or predicting the effect of observed terrestrial processes on stream nutrient signals, it is requisite to understand how stream networks can modulate terrestrial nutrient inputs. To date integrated understanding and modeling of physical and biological influences on nutrient concentrations at the stream network scale have been limited. However, watershed scale groundwater - surface water exchange (hydrologic turnover), concentration-variable biological uptake, and the interaction between the two can strongly modify stream water nutrient concentrations. Stream water and associated nutrients are lost to and replaced from groundwater with distinct nutrient concentrations while in-stream nutrients can also be retained by biological processes at rates that vary with concentration. We developed an empirically based network scale model to simulate the interaction between hydrologic turnover and concentration-dependent nutrient uptake across stream networks. Exchange and uptake parameters were measured using conservative and nutrient tracer addition experiments in the Bull Trout Watershed, central Idaho. We found that the interaction of hydrologic turnover and concentration-dependent uptake combined to modify and subsequently stabilize in-stream concentrations, with specific concentrations dependent on the magnitude of hydrologic turnover, groundwater concentrations, and the shape of nutrient uptake kinetic curves. We additionally found that by varying these physical and biological parameters within measured ranges we were able to generate a spectrum of stream network concentration distributions representing a continuum of shifting magnitudes of physical and biological influences on in-stream concentrations. These findings elucidate the important and variable role of

  10. A comparison between the theory and reality of full-scale step-feed nutrient removal systems.

    PubMed

    Johnson, B R; Goodwin, S; Daigger, G T; Crawford, G V

    2005-01-01

    Capacity enhancement and volume reduction benefits of step-feeding fully aerobic bioreactors has been well documented. Application of step-feed technology to biological nutrient removal (BNR) systems, particularly those removing nitrogen alone or both nitrogen and phosphorus, is relatively new to the industry. In recent years, a number of full-scale step-feed facilities have been brought into service. This paper reviews nine full-scale step-feed biological nutrient removal systems--both nitrogen removal alone, and nitrogen and phosphorus removal. The objective is to compare the theoretical benefits of such systems with their actual operation. The predicted benefits of reduced bioreactor volume or increased process capacity, reduced energy usage, more robust nitrification performance, and the flexibility to tune (or de-tune) nitrification efficiency were verified in full-scale systems. Equations are also presented that may be used in the prediction of step-feed benefits. There are two primary drivers for considering a step-feed biological reactor system: 1. Reduced bioreactor volume for a defined capacity or performance or increased process capacity given a fixed bioreactor volume. 2. More robust nitrification performance. Full-scale operation of these step-feed nutrient removal systems provides a real world basis for the claimed benefits of step-feed operation. These systems have uniformly shown additional capacity. A number of them have also exhibited more robust performance, especially during storms. Where possible, side-by-side comparisons of full-scale step-feed systems with non-step-feed systems have exhibited greater process reliability and flexibility.

  11. Using floating vegetation to remove nutrients from an anaerobic swine wastewater lagoon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods are needed for utilizing nutrients contained within animal wastewater lagoons. One potential method for removing nutrients is to have vegetation growing in the lagoon. A study was conducted from 2005-2007 to determine the feasibility of growing vegetation on floating platforms on a single ...

  12. Expert systems guide biological phosphorus removal

    SciTech Connect

    Krichten, D.J.; Wilson, K.D.; Tracy, K.D. )

    1991-10-01

    There is a large body of knowledge regarding optimum control strategies for new secondary wastewater treatment technology using an anaerobic selector to provide biological phosphorus removal. However, because the selector technology is new and the concepts differ somewhat from those used in conventional activated sludge wastewater treatment, a method of communicating this knowledge to plant operators is needed. Traditional methods such as classroom training and operating manuals are of limited effectiveness. The commonplace availability and low cost of the personal computer (PC) makes it practical to use a computer program to communicate the type of information required to control a wastewater treatment plant. Knowledge-based systems technology, commonly referred to as expert systems (ES) technology, is easy to use, provides useful information regarding a consistent control strategy, relieves the anxiety associated with learning a new process,' and provides instruction for inexperienced personnel. ES technology does not require special formatted input and is therefore easily accessible. All information required by the program is readily available through routine laboratory analysis, common plant instrumentation, or direct user observation. The program was designed for all levels of computer users and will run on all IBM-compatible or Apple MacIntosh systems.

  13. Enhanced biological phosphorus removal and its modeling for the activated sludge and membrane bioreactor processes.

    PubMed

    Zuthi, M F R; Guo, W S; Ngo, H H; Nghiem, L D; Hai, F I

    2013-07-01

    A modified activated sludge process (ASP) for enhanced biological phosphorus removal (EBPR) needs to sustain stable performance for wastewater treatment to avoid eutrophication in the aquatic environment. Unfortunately, the overall efficiency of the EBPR in ASPs and membrane bioreactors (MBRs) is frequently hindered by different operational/system constraints. Moreover, although phosphorus removal data from several wastewater treatment systems are available, a comprehensive mathematical model of the process is still lacking. This paper presents a critical review that highlights the core issues of the biological phosphorus removal in ASPs and MBRs while discussing the inhibitory process requirements for other nutrients' removal. This mini review also successfully provided an assessment of the available models for predicting phosphorus removal in both ASP and MBR systems. The advantages and limitations of the existing models were discussed together with the inclusion of few guidelines for their improvement.

  14. Nutrients, Recycling, and Biological Populations in Upwelling Ecosystems

    SciTech Connect

    Whitledge, T. E.

    1980-01-01

    Nutrient recycling has been studied in the upwelling areas of Baja California, Northwest Africa, and Peru. Regeneration by biological populations in these areas contributes significant quantities of recycled nitrogen which is utilized in productivity processes. Each area has a different combination of organisms which leads to differences in the relative contributions of zooplankton, nekton, or benthos to the nutrient cycles. Comparisons of ammonium regeneration rates of zooplankton and nekton-micronekton populations in the three upwelling areas show that zooplankton recycle relatively less nitrogen in the Baja California and Peru systems than nekton. In the Northwest Africa upwelling region, however, zooplankton, fish, and benthic inputs are all substantial. In recent years the Peruvian upwelling system has been altered with the decline of the anchoveta population and an increase in the importance of zooplankton in nutrient recycling. The distribution of recycled nitrogen (ammonium and urea) in transects across the shelf at 10°S and 15°S indicates that regeneration is relatively more important at 10°S in the region of the wide shelf. In both areas the distribution of ammonium and urea are not entirely coincident thereby indicating differences in their production and/or utilization.

  15. Nutrient removal and biodiesel production by integration of freshwater algae cultivation with piggery wastewater treatment.

    PubMed

    Zhu, Liandong; Wang, Zhongming; Shu, Qing; Takala, Josu; Hiltunen, Erkki; Feng, Pingzhong; Yuan, Zhenhong

    2013-09-01

    An integrated approach, which combined freshwater microalgae Chlorella zofingiensis cultivation with piggery wastewater treatment, was investigated in the present study. The characteristics of algal growth, lipid and biodiesel production, and nutrient removal were examined by using tubular bubble column photobioreactors to cultivate C. zofingiensis in piggery wastewater with six different concentrations. Pollutants in piggery wastewater were efficiently removed among all the treatments. The specific growth rate and biomass productivity were different among all the cultures. As the initial nutrient concentration increased, the lipid content of C. zofingiensis decreased. The differences in lipid and biodiesel productivity of C. zofingiensis among all the treatments mainly resulted from the differences in biomass productivity. It is worthy of note that the diluted piggery wastewater with 1900 mg L(-1) COD provided an optimal nutrient concentration for C. zofingiensis cultivation, where the advantageous nutrient removal and the highest productivities of biomass, lipid and biodiesel were presented.

  16. 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...

  17. 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...

  18. Biological phosphorus removal inhibition by roxarsone in batch culture systems.

    PubMed

    Guo, Qingfeng; Liu, Li; Hu, Zhenhu; Chen, Guowei

    2013-06-01

    Roxarsone has been extensively used in the feed of animals, which is usually excreted unchanged in the manure and eventually enter into animal wastewater, challenging the biological phosphorus removal processes. Knowledge of its inhibition effect is key for guiding treatment of roxarsone-contaminated wastewater, and is unfortunately keeping unclear. We study the inhibition of roxarsone on biological phosphorus removal processes for roxarsone-contaminated wastewater treatment, in terms of the removal and rates of chemical oxygen demand (COD), phosphate. Results showed that presence of roxarsone considerably limited the COD removals, especially at roxarsone concentration exceeding 40 mg L(-1). Additionally, roxarsone inhibited both phosphorus release and uptake processes, consistent with the phosphate profiles during the biological phosphorus removal processes; whereas, roxarsone is more toxic to phosphorus uptake process, than release function. The results indicated that it is roxarsone itself, rather than the inorganic arsenics, inhibit biological phosphorus removal processes within both aerobic and anaerobic roxarsone-contaminated wastewater treatment.

  19. Nutrient input and removal trends for agricultural soils in nine geographic regions in Arkansas.

    PubMed

    Slaton, Nathan A; Brye, Kristofor R; Daniels, Mike B; Daniel, Tommy C; Norman, Richard J; Miller, David M

    2004-01-01

    Knowledge of the balance between nutrient inputs and removals is required for identifying regions that possess an excess or deficit of nutrients. This assessment describes the balance between the agricultural nutrient inputs and removals for nine geographical districts within Arkansas from 1997 to 2001. The total N, P, and K inputs were summed for each district and included inorganic fertilizer and collectable nutrients excreted as poultry, turkey, dairy, and hog manures. Nutrients removed by harvested crops were summed and subtracted from total nutrient inputs to calculate the net nutrient balance. The net balances for N, P, and K were distributed across the hectarage used for row crop, hay, pasture, or combinations of these land uses. Row-crop agriculture predominates in the eastern one-third and animal agriculture predominates in the western two-thirds of Arkansas. Nutrients derived from poultry litter accounted for >92% of the total transportable manure N, P, and K. The three districts in the eastern one-third of Arkansas contained 95% of the row-crop hectarage and had net N and P balances that were near zero or negative. The six districts in the western two-thirds of Arkansas accounted for 89 to 100% of the animal populations, had positive net balances for N and P, and excess P ranged from 1 to 9 kg P ha(-1) when distributed across row-crop, hay, and pasture hectarage. Transport of excess nutrients, primarily in poultry litter, outside of the districts in western Arkansas is needed to achieve a balance between soil inputs and removals of P and N.

  20. ENGINEERING DESIGN CONFIGURATIONS FOR BIOLOGICAL AMMONIA REMOVAL

    EPA Science Inventory

    Many regions in the United States have excessive levels of nutrients including ammonia in their source waters. For example, farming and agricultural sources of ammonia in the Midwest contribute to relatively high levels of ammonia in many ground waters. Although ammonia in water ...

  1. Coupling the treatment of low strength anaerobic effluent with fermented biowaste for nutrient removal via nitrite.

    PubMed

    Katsou, E; Malamis, S; Frison, N; Fatone, F

    2015-02-01

    Nutrient removal via nitrite was investigated in a sequencing batch reactor (SBR) treating low strength effluent produced from an upflow anaerobic sludge blanket (UASB). Domestic organic waste (DOW) and vegetable and fruit waste (VFW) were fermented and applied as external carbon source to the SBR. Nutrient removal via nitrite was much higher when DOW fermentation liquid (FL) was applied rather than VFW FL and acetic acid. The DOW FL contained propionic acid and butyric acid in significant proportions, favouring the nutrient removal via nitrite, while the VFW FL contained mainly acetic acid, which was associated with lower nutrient via nitrite activity. The application of high volumetric nitrogen loading rate (vNLR = 0.19-0.21 kgN m(-3) d(-1)) in combination with low dissolved oxygen (DO) concentration during the aerobic phase, resulted in high and stable nitrite accumulation (NO2-N/NOx-N >97%). These conditions favoured the phosphorus uptake via nitrite, which reached high rates (5.95 ± 2.21 mgP (gVSS h)(-1)), while the aerobic phosphorus removal was much lower. Through mass balances, it was demonstrated that the application of the UASB-SBR process with nutrient removal via nitrite at a decentralized level is a sustainable solution for effective co-treatment of domestic sewage and biowaste.

  2. Control of COD/N ratio for nutrient removal in a modified membrane bioreactor (MBR) treating high strength wastewater.

    PubMed

    Fu, Zhimin; Yang, Fenglin; Zhou, Feifei; Xue, Yuan

    2009-01-01

    A modified membrane bioreactor (MBR) system has been developed to evaluate the efficiency of nutrient removal in treating synthetic high strength water. This study examined the effect of influent COD/N ratio on this system. Results showed that above 95.0% removal efficiencies of organic matter were achieved; indicating COD removal was irrespective of COD/N ratio. The average removal efficiencies of total nitrogen (TN) and phosphate (PO(4)(3-)-P) with a COD/N ratio of 9.3 were the highest at 90.6% and 90.5%, respectively. Furthermore, TN removal was primarily based on simultaneous nitrification and denitrification (SND) process occurred in the aerobic zone. Decreased COD/N ratios to 7.0 and 5.3, TN removal efficiencies in steady-states were 69.3% and 71.2%, respectively. Both aerobic SND and conventional biological nitrification/denitrification contributed to nitrogen removal and the latter played dominant effect. PO(4)(3-)-P-release and uptake process ceased in steady-states of COD/N 7.0 and 5.3, which decreased its removal efficiency significantly.

  3. Nutrient and biological conditions of selected small streams in the Edwards Plateau, central Texas, 2005-06, and implications for development of nutrient criteria

    USGS Publications Warehouse

    Mabe, Jeffrey A.

    2007-01-01

    During the summers of 2005 and 2006 the U.S. Geological Survey, in cooperation with the Texas Commission on Environmental Quality, evaluated nutrient and biological conditions in small streams in parts of the Edwards Plateau of Central Texas. Land-cover analysis was used to select 15 small streams that represented a gradient of conditions with the potential to affect nutrient concentrations across the study area, which comprises two of four subregions of the Edwards Plateau ecoregion. All 15 streams were sampled for water properties, nutrients, algae, benthic invertebrates, and fish in summer 2005, and eight streams were resampled in summer 2006. Streams that did not receive wastewater effluent had relatively low nutrient concentrations and were classified as oligotrophic; streams receiving wastewater effluent had relatively high nutrient concentrations and were classified as eutrophic. Nutrient concentrations measured in the least-disturbed streams closely matched the U.S. Environmental Protection Agency nutrient criteria recommendations based on estimated reference concentrations. Nitrogen/phosphorus ratios indicated streams not affected by wastewater effluent might be limited by phosphorus concentrations. Algal indicators of nutrient condition were closely related to dissolved nitrogen concentrations and streamflow conditions. Ambient dissolved nitrogen concentrations (nitrite plus nitrate) were positively correlated with benthic algal chlorophyll-a concentrations. The correlation of benthic algal chlorophyll-a with instantaneous nitrite plus nitrate load was stronger than correlations with ambient nutrients. Increased nutrient concentrations were associated with increased macroalgae cover, wider diel dissolved oxygen ranges, and reduced diel dissolved oxygen minimums. Benthic invertebrate aquatic life use scores generally were classified as High to Exceptional in study streams despite the influence of urbanization or wastewater effluent. Reductions in aquatic

  4. Biological potential of extraterrestrial materials - 1. Nutrients in carbonaceous meteorites, and effects on biological growth

    NASA Astrophysics Data System (ADS)

    Mautner, Michael N.

    1997-06-01

    Soil nutrient analysis of the Murchison C2 carbonaceous chondrite shows biologically available S, P, Ca, Mg, Na, K and Fe and cation exchange capacity (CEC) at levels comparable with terrestrial agricultural soils. Weathering, and aqueous, hydrothermal (121°C, 15 min) and high-temperature (550°C, 3 h) processing increase the extractable nutrients. Extractable phosphorus (by 0.3 M NH 4F + 0.1 M HCl) content, which may be growth-limiting, is 6.3 μg g -1 in the unprocessed meteorite, but increases to 81 μg g -1 by hydrothermal processing and weathering, and to 130 μg g -1 by high temperature processing. The cation exchange capacity (CEC), attributed mainly to the organic fraction, corresponds responds to 345 meq per 100 g of the polymer, suggesting one ionizable COOH or OH group per 3-4 aromatic rings. The Allende C3(V) meteorite has low extractable Ca, Mg and K, in parallel to its low organic content and CEC, but high extractable P levels (160 μg g -1). Biological effects are observed on growth of the soil microorganisms Flavobacterium oryzihabitans and Nocardia asteroides in meteorite extracts, and the population levels suggest that P is the limiting nutrient. Effects on plant growth are examined on Solanum tuberosum (potato), where extracts of the Murchison meteorite lead to enhanced growth and pigmentation. The biologically available organic and inorganic nutrients in carbonaceous chondrites can provide concentrated solutions for prebiotic and early life processes, and serve as soils and fertilizers for future space-based biological expansion.

  5. Assessment of the nutrient removal performance in integrated constructed wetlands with the self-organizing map.

    PubMed

    Zhang, Liang; Scholz, Miklas; Mustafa, Atif; Harrington, Rory

    2008-07-01

    The self-organizing map (SOM) model was applied to predict outflow nutrient concentrations for integrated constructed wetlands (ICWs) treating farmyard runoff. The SOM showed that the outflow ammonia-nitrogen concentrations were strongly correlated with water temperature and salt concentrations, indicating that ammonia-nitrogen removal is effective at low salt concentrations and comparatively high temperatures in ICWs. Soluble reactive phosphorus removal was predominantly affected by salt and dissolved oxygen concentrations. In addition, pH and temperature were weakly correlated with soluble reactive phosphorus removal, suggesting that soluble reactive phosphorus was easily removed within ICWs, if salt concentrations were low, and dissolved oxygen, temperature and pH values were high. The SOM model performed very well in predicting the nutrient concentrations with water quality variables such as temperature, conductivity and dissolved oxygen, which can be measured cost-effectively. The results indicate that the SOM model was an appropriate approach to monitor wastewater treatment processes in ICWs.

  6. 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.

  7. Hydraulic retention time effects on wastewater nutrient removal and bioproduct production via rotating algal biofilm reactor.

    PubMed

    Iman Shayan, Sahand; Agblevor, Foster A; Bertin, Lorenzo; Sims, Ronald C

    2016-07-01

    Rotating algal biofilm reactor (RABR) technology was successfully employed in an effective strategy to couple the removal of wastewater nutrients with accumulation of valuable bioproducts by grown algae. A secondary stage municipal wastewater was fed to the developed system and the effects of the hydraulic retention time (HRT) parameter on both nutrient removal and bioproduct production were evaluated under fed-batch operation mode. Two sets of bench scale RABRs were designed and operated with HRTs of 2 and 6days in order to provide competitive environment for algal growth. The HRT significantly affected nitrogen and phosphorus uptakes along with lipid and starch accumulations by microalgae in harvested biofilms. Domination of nitrogen removal in 2-day HRT with higher lipid accumulation (20% on dried weight basis) and phosphorus removal in 6-day HRT with higher starch production (27% on dried weight basis) was observed by comparing the performances of the RABRs in duplicate runs.

  8. 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.

  9. Vegetation effects on floating treatment wetland nutrient removal and harvesting strategies in urban stormwater ponds.

    PubMed

    Wang, Chih-Yu; Sample, David J; Bell, Cameron

    2014-11-15

    Floating treatment wetlands (FTWs) consist of emergent macrophytes that are placed on a floating mat in a pond for water treatment and aesthetic purposes. FTWs may have unique advantages with respect to treating urban runoff within existing retention ponds for excess nutrients. However, research is lacking in providing guidance on performance of specific species for treating urban runoff, and on timing of harvest. Harvesting is needed to remove nutrients permanently from the retention pond. We investigated vegetation effects on FTWs on nitrogen (N) and phosphorus (P) removal performance and storage in above-ground FTW macrophyte tissues. The study evaluated pickerelweed (PW, Pontederia cordata L.) and softstem bulrush (SB, Schoenoplectus tabernaemontani) over time in microcosms flushed with water obtained from a nearby urban retention pond in northern Virginia near Washington, DC. While the literature exhibits a wide range of experimental sizes, using the term mesocosm, we have chosen the term microcosm to reflect the small size of our vessel; and do not include effects of sediment. The experiment demonstrated PW outperformed SB for P and N removal. Based upon analysis of the accumulated nutrient removal over time, a harvest of the whole PW and SB plants in September or October is recommended. However, when harvesting only the aerial parts, we recommend harvesting above-ground PW tissues in July or August to maximize nutrient removal. This is because PW translocates most of its nutrients to below-ground storage organs in the fall, resulting in less nutrient mass in the above-ground tissue compared to the case in the summer (vegetative stage). Further research is suggested to investigate whether vegetation can be overly damaged from multiple harvests on an annual basis in temperate regions.

  10. A basic study on removal of nutrient salts in wastewater using plants (removal by mung beans; Phaseolus radiatus L).

    PubMed

    Azuma, T; Niiro, M; Motobu, H

    1992-01-01

    Many studies have reported on the removal of pollutants from wastewater using aquatic plants. The water hyacinth has been the most widely used and its system is the most well established. This system however, has a few problems in practical use. The purpose of this study is to obtain basic information on a new system that can substitute for a conventional system or be used as a secondary system to assist the conventional one. We first envisioned a model of this new system and then conducted a preliminary experiment using a small experimental unit to simulate the new system. The experiment showed that mung beans were a suitable plant for our study. Their removal rate of pollutants was the highest before they developed leaves and started photosynthesis. We found that nutrients were expelled outside the plant root when nutrient concentration inside the plant tissue became too high.

  11. Removal of Multiple Contaminants: Biological Treatment

    EPA Science Inventory

    This presentation contains (1) background material on nitrate, perchlorate and ammonia contamination in the continental US; (2) scientific background on biological drinking water treatment; (3) results of bench-scale anaerobic and aerobic treatment studies; (4) results of pilot-s...

  12. Removal of nutrients and metals by constructed and naturally created wetlands in the Las Vegas Valley, Nevada.

    PubMed

    Adhikari, Achyut R; Acharya, Kumud; Shanahan, Seth A; Zhou, Xiaoping

    2011-09-01

    Increased water use associated with rapid growth in the Las Vegas Valley has inadvertently led to the creation of unique wetland systems in Southern Nevada with an abundance of biological diversity. Constructed and naturally created wetlands in the Las Vegas Valley watershed were studied to characterize and understand their potential role for improving ecosystem services (i.e., water purification). Nutrient and metal removal was assessed at four sites including a natural urban runoff wetland, a constructed urban runoff wetland, a constructed wastewater wetland, and a natural urban runoff/wastewater wetland. Plant nutrient uptake was dependent on ambient nutrient concentrations in water and sediments of specific wetlands, irrespective of the type of plants present. Phosphorus was mostly concentrated in below-ground plant parts whereas nitrogen was concentrated in above-ground parts. As for metalloids, bulrushes were more efficient than cattails at taking up arsenic and selenium. Averaging all the wetland sites and plant species, total nitrogen, phosphorus, arsenic and selenium removal was 924.2, 61.5, 0.30, and 0.38 kg/ha/year, respectively. Our findings suggest that natural and created wetland systems can improve water quality in the Las Vegas Valley watershed for some common pollutants, however, other measures are still needed to improve water quality below regulatory thresholds.

  13. Comparison of four aquatic plant treatment systems for nutrient removal from eutrophied water.

    PubMed

    Li, Jihua; Yang, Xiaoying; Wang, Zhengfang; Shan, Ying; Zheng, Zheng

    2015-03-01

    Nutrient removal behaviors of four aquatic plant treatment systems (Oenanthe javanica, Iris pseudacorus L., Canna lily, and Potamogeton crispus) were systematically examined and compared. The kinetics of nutrient uptake were conducted with the standard depletion method. All four aquatic species exhibited a strong preference of ammonium nitrogen (NH4(+)-N) over nitrate nitrogen (NO3(-)-N) and nitrite nitrogen (NO2(-)-N). Main pathways of nutrient removal in the aquatic plant treatment system were examined in details. It was estimated that direct assimilation by plants accounted for 28.2-34.5% of N reduction and 25.2-33.4% of P reduction while substrate absorption accounted for 7.2-25.5% of N reduction and 7.3-25.0% of P reduction. The activity of urease and phosphatase in the substrates could indicate the aquatic plant treatment system's capability for reducing TN and soluble P load.

  14. Removal of nutrients from piggery wastewater using struvite precipitation and pyrogenation technology.

    PubMed

    Huang, Haiming; Xu, Chunlian; Zhang, Wei

    2011-02-01

    In this paper, removal of nutrients from piggery wastewater by struvite crystallization was conducted using a combined technology of low-cost magnesium source in struvite precipitation and recycling of the struvite pyrolysate in the process. In the present research, it was found that high concentrations of K(+) and Ca(2+) present in the solution significantly affected the removal of nutrients. When the struvite crystallization formed at the condition of dosing the magnesite pyrolysate at a Mg:N:P molar ratio of 2.5:1:1, and having a reaction time of 6 h, a majority of nutrients in piggery wastewater can be removed. Surface characterization analysis demonstrated that the main components of the pyrolysate of the obtained struvite were amorphous magnesium sodium phosphate (MgNaPO(4)) and MgO. When the struvite pyrolysate was recycled in the process at the pH range of 8.0-8.5, the precipitation effect was optimum. When the struvite pyrolysate was recycled repeatedly at pH 8.5 or without any adjustment of pH, the outcome of the removal of the nutrients in both cases was similar. With the increase in the number of recycle times, the performance of struvite precipitation progressively decreased. An economic evaluation showed that the combination of using low-cost material and recycling of struvite was feasible. Recycling struvite for three process cycles could save the chemical costs by 81% compared to the use of pure chemicals.

  15. Corn stover nutrient removal estimates for Central Iowa, U.S.A.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the most frequently asked questions to those striving to secure sustainable corn (Zea mays L.) stover feedstock supplies for Iowa’s new bioenergy conversion facilities is “what quantity of nutrients will be removed if I harvest my stover?”. Our objective is to summarize six years of field res...

  16. 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 CO2 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 CO2 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.

  17. Nutrient removal as a function of corn stover cutting height and cob harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One-pass harvest equipment has been developed to collect corn (Zea mays L.) grain, stover, and cobs: three plant components that can be used as bioenergy feedstock. Nutrients removed in these feedstocks have soil fertility implications and affect feedstock quality. The study objectives were to quant...

  18. Detection and prevention of enhanced biological phosphorus removal deterioration caused by Zoogloea overabundance.

    PubMed

    Montoya, T; Borrás, L; Aguado, D; Ferrer, J; Seco, A

    2008-01-01

    A sequencing batch reactor was operated in the conventional anaerobic-aerobic mode for enhanced biological phosphorus removal using acetate as the sole substrate. Despite the nutrients concentrations in the influent being high enough to satisfy the biological requirements, Zoogloea ramigera managed to grow in the system until it had negative effects on the process performance. The excess of exocellular polymeric material produced by this microorganism contributed to a viscous bulking phenomenon and caused important settling problems. The examination of the sludge under the microscope was a valuable tool to diagnose the cause of the imbalance in the process. The strategy adopted to avoid the deterioration of the process (changing key operational factors affecting the Z. ramigera development) allowed the successful recovery the enhanced biological phosphorus removal system. The effectiveness of this approach was confirmed by analyzing several parameters along the operational period (SVI, Y(PO4), TSS, %VSS...) together with microbiological examinations of the sludge.

  19. Biological nitrogen and phosphorus removal in membrane bioreactors: model development and parameter estimation.

    PubMed

    Cosenza, Alida; Mannina, Giorgio; Neumann, Marc B; Viviani, Gaspare; Vanrolleghem, Peter A

    2013-04-01

    Membrane bioreactors (MBR) are being increasingly used for wastewater treatment. Mathematical modeling of MBR systems plays a key role in order to better explain their characteristics. Several MBR models have been presented in the literature focusing on different aspects: biological models, models which include soluble microbial products (SMP), physical models able to describe the membrane fouling and integrated models which couple the SMP models with the physical models. However, only a few integrated models have been developed which take into account the relationships between membrane fouling and biological processes. With respect to biological phosphorus removal in MBR systems, due to the complexity of the process, practical use of the models is still limited. There is a vast knowledge (and consequently vast amount of data) on nutrient removal for conventional-activated sludge systems but only limited information on phosphorus removal for MBRs. Calibration of these complex integrated models still remains the main bottleneck to their employment. The paper presents an integrated mathematical model able to simultaneously describe biological phosphorus removal, SMP formation/degradation and physical processes which also include the removal of organic matter. The model has been calibrated with data collected in a UCT-MBR pilot plant, located at the Palermo wastewater treatment plant, applying a modified version of a recently developed calibration protocol. The calibrated model provides acceptable correspondence with experimental data and can be considered a useful tool for MBR design and operation.

  20. Innovative Biological Water Treatment for the Removal of Elevated Ammonia

    EPA Science Inventory

    The objective of this work was to demonstrate the effectiveness of an innovative and simple biological water treatment approach for removing 3.3 mg N/L ammonia and iron from water using a pilot study conducted at a utility in Iowa. Biological water treatment can be an effective a...

  1. Nutrient and dissolved organic carbon removal from water using mining and metallurgical by-products.

    PubMed

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

    2012-05-15

    Excess nutrient input to water bodies frequently results in algal blooms and development of oxygen deficient conditions. Mining or metallurgical by-products can potentially be utilised as filtration media within water treatment systems such as constructed wetlands, permeable reactive barriers, or drain liners. These materials may offer a cost-effective solution for the removal of nutrients and dissolved organic carbon (DOC) from natural waters. This study investigated steel-making, alumina refining (red mud and red sand) and heavy mineral processing by-products, as well as the low-cost mineral-based material calcined magnesia, in laboratory column trials. Influent water and column effluents were analysed for pH and flow rate, alkalinity, nutrient species and DOC, and a range of major cations and anions. In general, by-products with high Ca or Mg, and to a lesser extent those with high Fe content, were well-suited to nutrient and DOC removal from water. Of the individual materials examined, the heavy mineral processing residue neutralised used acid (NUA) exhibited the highest sorption capacity for P, and removed the greatest proportions of all N species and DOC from influent water. In general, NUA and mixtures containing NUA, particularly those with calcined magnesia or red mud/red sand were the most effective in removing nutrients and DOC from influent water. Post-treatment effluents from columns containing NUA and NUA/steel-making by-product, NUA/red sand and NUA/calcined magnesia mixtures exhibited large reductions in DOC, P and N concentrations and exhibited a shift in nutrient ratios away from potential N- and Si-limitation and towards potential P-limitation. If employed as part of a large-scale water treatment scheme, use of these mining and metallurgical by-products for nutrient removal could result in reduced algal biomass and improved water quality. Identification and effective implementation of mining by-products or blends thereof in constructed wetlands

  2. Identification and evaluation of a dominant alga from municipal wastewater in removal of nutrients.

    PubMed

    Yang, Yixuan; Tang, Fei; Su, Xiaoling; Yin, Hua; Ge, Fei

    2016-12-01

    To access better removal of nutrients with algae-based techniques, a dominant alga from real municipal wastewater was identified and its capacity in removing low concentrations of nitrogen (NH(+)4 or NO(-)3) and phosphorus (PO(3-)4) was evaluated. Results showed that Oedogonium brevicingulatum, a filamentous green alga, was confirmed as the dominant alga in the secondary effluent of a municipal wastewater treatment plant by polymerase chain reaction-denaturing gradient gel electrophoresis. Low concentrations of NH(+)4 or NO(-)3 (≤5 mg N L(-1)) and PO(3-)4 (≤0.5 mg P L(-1)) were 100% removed by the algae in a 7-d test. The maximum nutrient removal rate (Vmax) and the half-saturation constant (Km) for NH(+)4 (10.03 ± 0.95 mg g(-1)d(-1) and 0.19 ± 0.03 mg L(-1)) and NO(-)3 (8.43 ± 0.21 mg g(-1) d(-1) and 0.27 ± 0.11 mg L(-1)) indicated the uptake capability for NH(+)4 is higher than that for NO(-)3. Meanwhile, it showed higher affinity for PO(3-)4 (Vmax: 1.42 ± 0.02 mg g(-1) d(-1); Km: 0.02 ± 0.00 mg L(-1)) with NH(+)4 as nitrogen source than that (Vmax: 1.24 ± 0.15 mg g(-1) d(-1); Km: 0.06 ± 0.03 mg L(-1)) with NO(-)3 as nitrogen source. Moreover, nutrient removal efficiencies were observed steady when nitrogen/phosphorus ratio ranged from 5:1 to 20:1. These results suggest that the dominant algae from municipal wastewater have potentials to be applied in nutrient removal.

  3. Removal of arsenic and iron removal from drinking water using coagulation and biological treatment.

    PubMed

    Pramanik, Biplob Kumar; Pramanik, Sagor Kumar; Suja, Fatihah

    2016-02-01

    Effects of biological activated carbon (BAC), biological aerated filter (BAF), alum coagulation and Moringa oleifera coagulation were investigated to remove iron and arsenic contaminants from drinking water. At an initial dose of 5 mg/L, the removal efficiency for arsenic and iron was 63% and 58% respectively using alum, and 47% and 41% respectively using Moringa oleifera. The removal of both contaminants increased with the increase in coagulant dose and decrease in pH. Biological processes were more effective in removing these contaminants than coagulation. Compared to BAF, BAC gave greater removal of both arsenic and iron, removing 85% and 74%, respectively. Longer contact time for both processes could reduce the greater concentration of arsenic and iron contaminants. The addition of coagulation (at 5 mg/L dosage) and a biological process (with 15 or 60 min contact time) could significantly increase removal efficiency, and the maximum removal was observed for the combination of alum and BAC treatment (60 min contact time), with 100% and 98.56% for arsenic and iron respectively. The reduction efficiency of arsenic and iron reduced with the increase in the concentration of dissolved organics in the feedwater due to the adsorption competition between organic molecules and heavy metals.

  4. Cultivation of Chlorella protothecoides with urban wastewater in continuous photobioreactor: biomass productivity and nutrient removal.

    PubMed

    Ramos Tercero, E A; Sforza, E; Morandini, M; Bertucco, A

    2014-02-01

    The capability to grow microalgae in nonsterilized wastewater is essential for an application of this technology in an actual industrial process. Batch experiments were carried out with the species in nonsterilized urban wastewater from local treatment plants to measure both the algal growth and the nutrient consumption. Chlorella protothecoides showed a high specific growth rate (about 1 day(-1)), and no effects of bacterial contamination were observed. Then, this microalgae was grown in a continuous photobioreactor with CO₂-air aeration in order to verify the feasibility of an integrated process of the removal of nutrient from real wastewaters. Different residence times were tested, and biomass productivity and nutrients removal were measured. A maximum of microalgae productivity was found at around 0.8 day of residence time in agreement with theoretical expectation in the case of light-limited cultures. In addition, N-NH₄ and P-PO₄ removal rates were determined in order to model the kinetic of nutrients uptake. Results from batch and continuous experiments were used to propose an integrated process scheme of wastewater treatment at industrial scale including a section with C. protothecoides.

  5. Growth and efficiency of nutrient removal by Salix jiangsuensis J172 for phytoremediation of urban wastewater.

    PubMed

    Shi, Xiang; Sun, Haijing; Pan, Hongwei; Chen, Yitai; Jiang, Zeping; Liu, Jianfeng; Wang, Shufeng

    2016-02-01

    Willows are a group of versatile tree species that may have multiple environmental applications. In the present study, Salix jiangsuensis J172 plants were grown in the fixed mats as an economic plant-based treatment system to evaluate its potential for removing nutrients in wastewater. Plants grew normally in wastewater compared with those in Hoagland solution. However, wastewater containing a high concentration of chlorine ions was toxic to S. jiangsuensis J172 plants. The plants accumulated large amounts of nitrogen and phosphorus in aboveground tissues under conditions of abundant supply. The removal efficiency for raw wastewater was 82.18-87.78 % for nitrogen, 57.35-65.58 % for phosphorus, and 58.24-59.90 % for chemical oxygen demand. Nutrient removal efficiency was positively correlated with the initial nutrient supply. The results show that S. jiangsuensis J172 grown in the fixed mat economic plant-based treatment system with nutrient-rich, eutrophic water may be an effective, low-cost phytoremediation technology to treat water containing undesirable levels of wastewater.

  6. 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.

  7. Enhanced nutrient removal in three types of step feeding process from municipal wastewater.

    PubMed

    Peng, Yongzhen; Ge, Shijian

    2011-06-01

    An anoxic/oxic step feeding process was improved to enhance nutrient removal by reconfiguring the process into (1) anaerobic/anoxic/oxic step feeding process or (2) modified University of Capetown (UCT) step feeding process. Enhanced nitrogen and phosphorus removal and optimized organics utilization were obtained simultaneously in the modified UCT type with both internal and sludge recycle ratios of 75% as well as anaerobic/anoxic/oxic volume ratio of 1:3:6. Specifically, the UCT configuration and optimized operational conditions lead to the enrichment of denitrifying phosphorus removal microorganisms and achieved improved anaerobic P-release and anoxic P-uptake activities, which were beneficial to the denitrifying phosphorus removal activities and removal efficiencies. Due to high mixed liquor suspended solid and uneven distributed dissolved oxygen, 35% of total nitrogen was eliminated through simultaneous nitrification and denitrification process in aerobic zones. Moreover, 62 ± 6% of influent chemical oxygen demands was involved in the denitrification or phosphorus release processes.

  8. 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.

  9. Impacts of sewage effluent on tree survival, water quality and nutrient removal in coastal plain swamps

    SciTech Connect

    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 the sewage nutrient load to the swamps.

  10. Effect of Nutrient/Carbon Supplements on Biological Phosphate and Nitrate Uptake by Protozoan Isolates

    NASA Astrophysics Data System (ADS)

    Akpor, O. B.; Momba, M. N. B.; Okonkwo, J.

    This study was aimed at investigating the effect of nine different nutrient/carbon supplements in mixed liquor on nutrient uptake ability of three wastewater protozoan isolates, which have previously been screened for phosphate and nitrate uptake efficiency. The results revealed that over 50% of phosphate was removed in the presence of sodium acetate, glucose or sucrose. Similarly, nitrate uptake of over 60% was observed in the presence of sodium acetate, sodium succinate, glucose or sucrose. These trends were common in all the isolates. Chemical Oxygen Demand (COD) removal in the mixed liquor was only found to be significantly removed in mixed liquors that were supplemented with glucose, sucrose or sodium succinate. In the presence of sodium acetate, COD was observed to increase. The findings of this investigation have revealed that nutrient uptake and COD removal by the test protozoan isolates may be dependent primarily on the initial nutrient supplement in mixed liquor.

  11. Increased microalgae growth and nutrient removal using balanced N:P ratio in wastewater.

    PubMed

    Lee, Seung-Hoon; Ahn, Chi-Yong; Jo, Beom-Ho; Lee, Sang-Ah; Park, Ji-Yeon; An, Kwang-Guk; Oh, Hee-Mock

    2013-01-01

    Microalgal cultivation using wastewater is now regarded as essential for biodiesel production, as two goals can be achieved simultaneously; that is, nutrient removal efficiency and biomass production. Therefore, this study examined the effects of carbon sources, the N:P ratio, and the hydraulic retention time (HRT) to identify the optimal conditions for nutrient removal efficiency and biomass production. The effluent from a 2nd lagoon was used to cultivate microalgae. Whereas the algal species diversity and lipid content increased with a longer HRT, the algal biomass productivity decreased. Different carbon sources also affected the algal species composition. Diatoms were dominant with an increased pH when bicarbonate was supplied. However, 2% CO(2) gas led to a lower pH and the dominance of filamentous green algae with a much lower biomass productivity. Among the experiments, the highest chlorophyll-a concentration and lipid productivity were obtained with the addition of phosphate up to 0.5 mg/l P, since phosphorus was in short supply compared with nitrogen. The N and P removal efficiencies were also higher with a balanced N:P ratio, based on the addition of phosphate. Thus, optimizing the N:P ratio for the dominant algae could be critical in attaining higher algal growth, lipid productivity, and nutrient removal efficiency.

  12. Low temperature biological phosphorus removal and partial nitrification in a pilot sequencing batch reactor system.

    PubMed

    Yuan, Qiuyan; Oleszkiewicz, Jan A

    2011-01-01

    Partial nitrification and biological phosphorus removal appear to hold promise of a cost-effective and sustainable biological nutrient removal process. Pilot sequencing batch reactors (SBRs) were operated under anaerobic/aerobic configuration for 8 months. It was found that biological phosphorus removal can be achieved in an SBR system, along with the partial nitrification process. Sufficient volatile fatty acids supply was the key for enhanced biological phosphorus removal. This experiment demonstrated that partial nitrification can be achieved even at low temperature with high dissolved oxygen (>3 mg/L) concentration. Shorter solid retention time (SRT) for nitrite oxidizing bacteria (NOB) than for ammonia oxidizing bacteria due to the nitrite substrate limitation at the beginning of the aeration cycle was the reason that caused NOB wash-out. Controlling SRT should be the strategy for an SBR operated in cold climate to achieve partial nitrification. It was also found that the aerobic phosphorus accumulating organisms' P-uptake was more sensitive to nitrite inhibition than the process of anaerobic P-release.

  13. Estimating the carrying capacity of green mussel cultivation by using net nutrient removal model.

    PubMed

    Srisunont, Chayarat; Babel, Sandhya

    2016-11-15

    This study aims to evaluate the nutrient removal potential and carrying capacity of green mussel cultivation by using the mass balance model. The developed model takes into consideration the green mussel growth rate, density and chlorophyll a concentration. The data employed in this study were based on culture conditions at Sriracha Fisheries Research Station, Thailand. Results show that net nutrient removal by green mussel is 3302, 380, and 124mg/year/indv for carbon, nitrogen, and phosphorus respectively. The carrying capacity of green mussel cultivation was found to be 300indv/m(2) based on chlorophyll a concentration which will not release phosphorus in the water environment beyond the standard (45μg-PO4(-3)-P/L). Higher chlorophyll a concentration results in lowered green mussel carrying capacity. This model can assist farm operators with possible management strategies for a sustainable mussel cultivation and protection of the marine environment.

  14. 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.

  15. 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.

  16. Nutrient removal through autumn harvest of Phragmites australis and Thypha latifolia shoots in relation to nutrient loading in a wetland system used for polishing sewage treatment plant effluent.

    PubMed

    Toet, Sylvia; Bouwman, Meike; Cevaal, Annechien; Verhoeven, Jos T A

    2005-01-01

    The efficacy and feasibility of annual harvesting of Phragmites australis and Typha latifolia shoots in autumn for nutrient removal was evaluated in a wetland system used for polishing sewage treatment plant (STP) effluent. Aboveground biomass and nutrient dynamics nutrient removal through harvest were studied in parallel ditches with stands of Phragmites or Typha that were mown in October during two successive years. The inflow rate of STP effluent to the ditches was experimentally varied, resulting in pairs of ditches with mean hydraulic retention times (HRT) of 0.3, 0.8, 2.3, and 9.3 days, corresponding to N and P mass loading rates of 122-4190 g N m(-2) yr(-1) and 28.3-994 g P m(-2) yr(-1). Nitrogen and P removal efficiency by harvest of Phragmites and Typha shoots in October increased with increasing HRT, despite the opposite HRT effect on N and P standing stocks. This removal through harvest appeared to be useful in treatment wetlands with N and P mass loading rates lower than approximately 120 g N m(-2) yr(-1) and 30 g P m(-2) yr(-1), corresponding to a HRT of roughly 9 days in the ditches of this wetland system. At the HRT of 9.3 days, the annual mass input to the ditches was reduced through the harvest by 7.0-11% and 4.5 -9.2% for N and P, respectively. At the higher nutrient mass loading rates, the nutrient removal through harvest was insignificant compared to the mass inputs. The vitality of Phragmites and Typha, measured as maximum aboveground biomass, was not affected by the annual cutting of the shoots in autumn over two years. The Typha stands yielded higher N and P removal efficiencies through shoot harvest than the Phragmites stands, which was largely the result of lower decreases in N and P standing stocks between August and October. This difference in nutrient standing stocks between the two species was caused by a combined effect of greater decreases in nutrient concentrations largely due to higher nutrient retranslocation efficiencies of

  17. Influence of wastewater composition on nutrient removal behaviors in the new anaerobic–anoxic/nitrifying/induced crystallization process

    PubMed Central

    Shi, Jing; Lu, Xiwu; Yu, Ran; Gu, Qian; Zhou, Yi

    2013-01-01

    In this study, the new anaerobic–anoxic/nitrifying/induced crystallization (A2N–IC) system was compared with anaerobic-anoxic/nitrifying (A2N) process to investigate nutrient removal performance under different influent COD and ammonia concentrations. Ammonia and COD removal rates were very stable in both processes, which were maintained at 84.9% and 86.6% when the influent ammonia varied from 30 mg L−1 to 45 mg L−1 and COD ranged from 250 mg L−1 to 300 mg L−1. The effluent phosphorus always maintained below 0.2 mg L−1 in A2N–IC, whereas in A2N the effluent phosphorus concentration was 0.4–1.7 mg L−1, demonstrating that A2N–IC is suitable to apply in a broader influent COD and ammonia concentration range. Under higher influent COD (300 mg L−1) or lower ammonia conditions (30 mg L−1), the main function of chemical induced crystallization was to coordinate better nutrient ratio for anoxic phosphorus uptake, whereas under high phosphorus concentration, it was to reduce phosphorus loading for biological system. Under the similar influent wastewater compositions, phosphorus release amounts were always lower in A2N–IC. To clarify the decrease procedure of phosphorus release in the A2N–IC, the equilibrium between chemical phosphorus removal and biological phosphorus removal in A2N–IC was analyzed by mass balance equations. During the long-term experiment, some undesirable phenomena were observed: the declining nitrification in post-aerobic tank and calcium phosphorus precipitation in the anaerobic tank. The reasons were analyzed; furthermore, the corresponding improvements were proposed. Nitrification effect could be enhanced in the post-aerobic tank, therefore ammonia removal rate could be increased; and biologically induced phosphorus precipitation could be inhibited by controlling pH at the anaerobic stage, so the phosphorus release and recovery could be improved. PMID:24596502

  18. Boosted Regression Tree Models to Explain Watershed Nutrient Concentrations and Biological Condition

    EPA Science Inventory

    Boosted regression tree (BRT) models were developed to quantify the nonlinear relationships between landscape variables and nutrient concentrations in a mesoscale mixed land cover watershed during base-flow conditions. Factors that affect instream biological components, based on ...

  19. DEVELOPMENT OF NUTRIENT EXPOSURE AND BIOLOGICAL RESPONSE INDICATORS FOR LAKE MICHIGAN COASTAL WETLANDS

    EPA Science Inventory

    This study examines how landscape-scale gradient affect sedimentation rates, nutrient exposure, and biological responses in Lake Michigan coastal wetlands, and assess indicators for these trends. Twenty riverine coastal wetlands in Lake Michigan (Herdendorf 1981) were selected t...

  20. Effects of Cd(II) on wastewater biological nitrogen and phosphorus removal.

    PubMed

    Chen, Hong-Bo; Wang, Dong-Bo; Li, Xiao-Ming; Yang, Qi; Luo, Kun; Zeng, Guang-Ming; Tang, Mao-Lin

    2014-12-01

    Short-term and long-term effects of Cd(II) on wastewater biological nitrogen and phosphorus removal were investigated with respect to microorganism abundances, enzyme activities, and polyhydroxyalkanoates (PHAs) and glycogen transformations. Though no obvious effects on wastewater biological nutrient removal were observed after short-term exposure, the long-term exposure of 10 mg L(-)(1) Cd(II) inhibited nitrification and phosphorus uptake. Compared with the absence of Cd(II), the presence of 10 mg L(-1) of Cd(II) decreased total nitrogen and phosphorus removal efficiencies from 97% and 98% to 88% and 18%, respectively. Mechanism studies revealed that Cd(II) affected the transformations of intracellular PHAs and glycogen, and the activities of oxidoreductase and polyphosphate kinase, resulted in the decrease of nitrite oxidizing bacteria and polyphosphate accumulating organisms abundance, which might be the major reason for the negative effects of long-term exposure to 10 mg L(-1) Cd(II) on biological nitrogen and phosphorus removal.

  1. Biological removal of phenol from wastewaters: a mini review

    NASA Astrophysics Data System (ADS)

    Pradeep, N. V.; Anupama, S.; Navya, K.; Shalini, H. N.; Idris, M.; Hampannavar, U. S.

    2015-06-01

    Phenol and its derivatives are common water pollutants and include wide variety of organic chemicals. Phenol poisoning can occur by skin absorption, inhalation, ingestion and various other methods which can result in health effects. High exposures to phenol may be fatal to human beings. Accumulation of phenol creates toxicity both for flora and fauna. Therefore, removal of phenol is crucial to perpetuate the environment and individual. Among various treatment methods available for removal of phenols, biodegradation is environmental friendly. Biological methods are gaining importance as they convert the wastes into harmless end products. The present work focuses on assessment of biological removal (biodegradation) of phenol. Various factors influence the efficiency of biodegradation of phenol such as ability of the microorganism, enzymes involved, the mechanism of degradation and influencing factors. This study describes about the sources of phenol, adverse effects on the environment, microorganisms involved in the biodegradation (aerobic and anaerobic) and enzymes that polymerize phenol.

  2. BOM removal during biological treatment: A first-order model

    SciTech Connect

    Huck, P.M. ); Zhang, S. . Dept. of Civil Engineering); Price, M.L. )

    1994-06-01

    Using data from two pilot-scale studies and one full-scale investigation, this article demonstrates that the removal rate in biological water treatment is proportional to the influence concentration to the bioreactor, i.e., a first-order process. This is true not only for measures of biodegradable organic matter, e.g., assimilable organic carbon, but also for precursors of chlorination by-products such as trihalomethanes. The slope of the removal rate versus the influent concentration relationship is termed the average specific removal rate, r[sub AS]. When data were available from different studies, the r[sub AS] values tended to fall in the same range. With a first-order model, the performance of biological treatment in a given situation can be estimated from limited data. The model is suggested as an approach for the preliminary design of bioreactors for drinking water treatment.

  3. A novel control strategy for efficient biological phosphorus removal with carbon-limited wastewaters.

    PubMed

    Guerrero, Javier; Guisasola, Albert; Baeza, Juan A

    2014-01-01

    This work shows the development and the in silico evaluation of a novel control strategy aiming at successful biological phosphorus removal in a wastewater treatment plant operating in an A(2)/O configuration with carbon-limited influent. The principle of this novel approach is that the phosphorus in the effluent can be controlled with the nitrate setpoint in the anoxic reactor as manipulated variable. The theoretical background behind this control strategy is that reducing nitrate entrance to the anoxic reactor would result in more organic matter available for biological phosphorus removal. Thus, phosphorus removal would be enhanced at the expense of increasing nitrate in the effluent (but always below legal limits). The work shows the control development, tuning and performance in comparison to open-loop conditions and to two other conventional control strategies for phosphorus removal based on organic matter and metal addition. It is shown that the novel proposed strategy achieves positive nutrient removal results with similar operational costs to the other control strategies and open-loop operation.

  4. Protozoan biomass relation to nutrient and chemical oxygen demand removal in activated sludge mixed liquor.

    PubMed

    Akpor, Oghenerobor B; Momba, Maggy N B; Okonkwo, Jonathan O

    2008-08-01

    The relationship between biomass concentration to nutrient and chemical oxygen demand (COD) removal in mixed liquor supplemented with sodium acetate was investigated, using three protozoan isolates and three different initial biomass concentrations (10(1), 10(2) and 10(3) cells/mL). The study was carried out in a shaking flask environment at a shaking speed of 100 rpm for 96 h at 25 degrees C. Aliquot samples were taken periodically for the determination of phosphate, nitrate, COD and dissolved oxygen, using standard methods. The results revealed remarkable phosphate removal of 82-95% at biomass concentration of 10(3)cells/mL. A high nitrate removal of over 87% was observed at all initial biomass concentration in mixed liquor. There was an observed COD increase of over 50% in mixed liquor in at the end of 96-h incubation and this was irrespective of initial biomass concentration used for inoculation. The study shows the trend in nutrient and COD removal at different biomass concentrations of the test isolates in mixed liquor.

  5. 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.

  6. Effect of the N/P ratio on biomass productivity and nutrient removal from municipal wastewater.

    PubMed

    Choi, Hee Jeong; Lee, Seung Mok

    2015-04-01

    The aim of this study is to investigate the effect of the N/P ratio on biomass growth with the simultaneous removal of nutrients from municipal wastewaters. An optical panel photobioreactor is employed for this investigation because it provides a uniform light distribution within the reactor, which enhances the efficiency of the reactor in the cultivation of microalgae. The N/P ratio is varied over a wide range, i.e., from 5 to 30, for the assessment of its effect on biomass productivity. There is not a strong correlation between biomass productivity and TN removal, and these factors do not seem to be proportional in the wastewater using the microalgae we employed. In contrast, the TP removal depends greatly on both the N/P ratio and biomass productivity. The optimum value of the N/P ratio for biomass productivity in and nutrient removal from municipal wastewater treatment using microalgae varies from 5 to 30, depending on the ecological conditions in the wastewater.

  7. Growth of three microalgae strains and nutrient removal from an agro-zootechnical digestate.

    PubMed

    Franchino, Marta; Comino, Elena; Bona, Francesca; Riggio, Vincenzo A

    2013-07-01

    In this paper three microalgae strains (Neochloris oleoabundans, Chlorella vulgaris and Scenedesmus obliquus) were cultivated on an agro-zootechnical digestate in comparable conditions. The material used as growth media was obtained from a pilot plant anaerobic digestor used to digest several mixes of cattle slurry and raw cheese whey. The main aims were to compare the algae growth, their tolerance with respect to the various dilutions of digestate, their nutrient removal efficiency and their role in the transformation of nitrogen compounds. C. vulgaris presented the highest elimination capacity of ammonium in 1:10 digestate sample; it was also observed that only 4% of ammonia was removed with stripping, microalgal and bacterial consortium recovered the remaining 96%. The three strains almost completely removed different nitrogen forms and phosphate in 11d. The results show that microalgal biomass production offers real opportunities for addressing issues such CO2 sequestration, biofuel production and wastewater treatment.

  8. Biological nitrate removal using wheat straw and PLA as substrate.

    PubMed

    Fan, Zhenxing; Hu, Jun; Wang, Jianlong

    2012-01-01

    Biological nitrate removal using wheat straw and polylactic acid (PLA) as both carbon source and biofilm support was investigated. The results showed that biofilm could develop on the surface of wheat straw within 15 d, the denitrification rate was 0.067 mg-N/(g-wheat straw x h) and nitrate removal efficiency was about 100%. For PLA, the time required for biofilm development was 40 d, the denitrification rate was 0.0026 mg-N/(g-PLA x h) and nitrate removal efficiency could also reach 100%. Temperature had a substantial influence on the denitrification performance of both wheat straw and PLA. The FTIR analysis and SEM observation confirmed that wheat straw and PLA were used for denitrification, and explained some reasons for the differences between the two substrates. The wheat straw was superior to PLA when used as carbon source for nitrate removal, in terms of the denitrification rate.

  9. Removal of geosmin and 2-methylisoborneol by biological filtration.

    PubMed

    Elhadi, S L N; Huck, P M; Slawson, R M

    2004-01-01

    The quality of drinking water is sometimes diminished by the presence of certain compounds that can impart particular tastes or odours. One of the most common and problematic types of taste and odour is the earthy/musty odour produced by geosmin (trans-1, 10-dimethyl-trans-9-decalol) and MIB (2-methylisoborneol). Taste and odour treatment processes including powdered activated carbon, and oxidation using chlorine, chloramines, potassium permanganate, and sometimes even ozone are largely ineffective for reducing these compounds to below their odour threshold concentration levels. Ozonation followed by biological filtration, however, has the potential to provide effective treatment. Ozone provides partial removal of geosmin and MIB but also creates other compounds more amenable to biodegradation and potentially undesirable biological instability. Subsequent biofiltration can remove residual geosmin and MIB in addition to removing these other biodegradable compounds. Bench scale experiments were conducted using two parallel filter columns containing fresh and exhausted granular activated carbon (GAC) media and sand. Source water consisted of dechlorinated tap water to which geosmin and MIB were added, as well as, a cocktail of easily biodegradable organic matter (i.e. typical ozonation by-products) in order to simulate water that had been subjected to ozonation prior to filtration. Using fresh GAC, total removals of geosmin ranged from 76 to 100% and total MIB removals ranged from 47% to 100%. The exhausted GAC initially removed less geosmin and MIB but removals increased over time. Overall the results of these experiments are encouraging for the use of biofiltration following ozonation as a means of geosmin and MIB removal. These results provide important information with respect to the role biofilters play during their startup phase in the reduction of these particular compounds. In addition, the results demonstrate the potential biofilters have in responding to

  10. 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.

  11. Thermophilic biological nitrogen removal in industrial wastewater treatment.

    PubMed

    Lopez-Vazquez, C M; Kubare, M; Saroj, D P; Chikamba, C; Schwarz, J; Daims, H; Brdjanovic, D

    2014-01-01

    Nitrification is an integral part of biological nitrogen removal processes and usually the limiting step in wastewater treatment systems. Since nitrification is often considered not feasible at temperatures higher than 40 °C, warm industrial effluents (with operating temperatures higher than 40 °C) need to be cooled down prior to biological treatment, which increases the energy and operating costs of the plants for cooling purposes. This study describes the occurrence of thermophilic biological nitrogen removal activity (nitritation, nitratation, and denitrification) at a temperature as high as 50 °C in an activated sludge wastewater treatment plant treating wastewater from an oil refinery. Using a modified two-step nitrification-two-step denitrification mathematical model extended with the incorporation of double Arrhenius equations, the nitrification (nitrititation and nitratation) and denitrification activities were described including the cease in biomass activity at 55 °C. Fluorescence in situ hybridization (FISH) analyses revealed that Nitrosomonas halotolerant and obligatehalophilic and Nitrosomonas oligotropha (known ammonia-oxidizing organisms) and Nitrospira sublineage II (nitrite-oxidizing organism (NOB)) were observed using the FISH probes applied in this study. In particular, this is the first time that Nitrospira sublineage II, a moderatedly thermophilic NOB, is observed in an engineered full-scale (industrial) wastewater treatment system at temperatures as high as 50 °C. These observations suggest that thermophilic biological nitrogen removal can be attained in wastewater treatment systems, which may further contribute to the optimization of the biological nitrogen removal processes in wastewater treatment systems that treat warm wastewater streams.

  12. Biological phosphorus and nitrogen removal in sequencing batch reactors: effects of cycle length, dissolved oxygen concentration and influent particulate matter.

    PubMed

    Ginige, Maneesha P; Kayaalp, Ahmet S; Cheng, Ka Yu; Wylie, Jason; Kaksonen, Anna H

    2013-01-01

    Removal of phosphorus (P) and nitrogen (N) from municipal wastewaters is required to mitigate eutrophication of receiving water bodies. While most treatment plants achieve good N removal using influent carbon (C), the use of influent C to facilitate enhanced biological phosphorus removal (EBPR) is poorly explored. A number of operational parameters can facilitate optimum use of influent C and this study investigated the effects of cycle length, dissolved oxygen (DO) concentration during aerobic period and influent solids on biological P and N removal in sequencing batch reactors (SRBs) using municipal wastewaters. Increasing cycle length from 3 to 6 h increased P removal efficiency, which was attributed to larger portion of N being removed via nitrite pathway and more biodegradable organic C becoming available for EBPR. Further increasing cycle length from 6 to 8 h decreased P removal efficiencies as the demand for biodegradable organic C for denitrification increased as a result of complete nitrification. Decreasing DO concentration in the aerobic period from 2 to 0.8 mg L(-1) increased P removal efficiency but decreased nitrification rates possibly due to oxygen limitation. Further, sedimented wastewater was proved to be a better influent stream than non-sedimented wastewater possibility due to the detrimental effect of particulate matter on biological nutrient removal.

  13. 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.

  14. 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

  15. Microalgae screening under CO2 stress: Growth and micro-nutrients removal efficiency.

    PubMed

    Hussain, Fida; Shah, Syed Zahir; Zhou, Wenguang; Iqbal, Munawar

    2017-03-30

    Algae are one of the promising agents for greenhouse gas reduction and biofuel production. Different technologies have been developed and introduced in last decades for algae growth. Algae plays a very imperative role in the aquatic ecosystem regarding CO2 reduction and micro-nutrient removal. In present investigation, eight locally isolated (microalgae) strains and two pure strains were studied. The selected microalgae were grown under variable CO2 concentration and CO2 biofixation efficiencies along with micro-nutrient removal were monitored. Among selected strains, three strains (UMN266, UMN268 and UTEX 2714 showed adaptability up to 20% CO2 concentration with high biomass production of 1.3, 1.4 and 1.21g/L, respectively, whereas UTEX 78 and UMN 230 growth was slow under high CO2 concentration (20% CO2). However, in step wise CO2 feeding, the growth of UTEX 78 and UMN 230 improved considerably and up to 0.9 and 0.97 (g/L) biomasses were recorded, respectively. All algae strains showed high growth rate at 2% CO2 feeding and nitrogen, phosphorus and ammonia removal from the simulated media were also significant. The fast-growing microalgae species tolerant up to 20% CO2 concentration and could be used for flue gas mitigation and valuable products production. These results can contribute to understand the nature of CO2 bio-fixation and microalgae could be a potential alternative for CO2 fixation.

  16. Nutrient removal and biofuel production in high rate algal pond using real municipal wastewater.

    PubMed

    Kim, Byung-Hyuk; Kang, Zion; Ramanan, Rishiram; Choi, Jong-Eun; Cho, Dae-Hyun; Oh, Hee-Mock; Kim, Hee-Sik

    2014-08-01

    This study evaluated the growth and nutrient removal ability of an indigenous algal consortium on real untreated municipal wastewater in a high rate algal pond (HRAP). The HRAP was operated semicontinuously under different hydraulic retention times (HRT: 2, 4, 6, and 8 days). The average removal efficiencies of chemical oxygen demand, and total nitrogen and phosphate of real municipal wastewater were maintained at 85.44 ± 5.10%, 92.74 ± 5.82%, and 82.85 ± 8.63%, respectively, in 2 day HRT. Algae dominated the consortium and showed high settling efficiency (99%), and biomass and lipid productivity of 0.500 ± 0.03 g/l/day and 0.103 ± 0.0083 g/l/day (2 day HRT), respectively. Fatty acid methyl ester analysis revealed a predominance of palmitate (C16:0), palmitoleate (C16:1), linoleate (C18:2), and linolenate (C18:3). Microalgal diversity analyses determined the presence of Chlorella, Scenedesmus, and Stigeoclonium as the dominant microalgae. The algal consortium provides significant value not only in terms of energy savings and nutrient removal but also because of its bioenergy potential as indicated by the lipid content (20-23%) and FAME profiling.

  17. A high loading overland flow system: Impacts on soil characteristics, grass constituents, yields and nutrient removal.

    PubMed

    Wen, C G; Chen, T H; Hsu, F H; Lu, C H; Lin, J B; Chang, C H; Chang, S P; Lee, C S

    2007-04-01

    The objectives of this paper are to determine effects of different grass species and their harvests on pollutant removal, elucidate impacts on soil characteristics and grass constituents, observe grass yield and quantify nutrient uptake by vegetation in an overland flow system (OLFS). Polluted creek water was applied to eight channels in the OLFS, which were planted with Paragrass, Nilegrass, Cattail, and Vetiver, with each two channels being randomly planted with a given grass species. The grass in one channel was harvested while that in the other channel was not. At a high rate of 27.8 m d(-1) hydraulic loading, the removal efficiencies of conventional pollutants such as BOD, COD, suspended solids (SS), and total coliforms in wastewater are not affected by the type of the grasses species, but those of nitrogen and phosphorus are affected by different species. Overall average removal efficiencies of BOD, COD, SS, ammonia, total nitrogen, total phosphorus and total coliforms through the OLFS are 42%, 48%, 78%, 47%, 40%, 33% and 89%, respectively. The concentration of nitrate, however, increases due to nitrification. Soil characteristics in OLFS have been changed significantly; specific conductivity, organic matter, exchangeable magnesium, extractable copper and zinc in soils all increase with time while pHs decrease. During the winter season, there is a significant accumulation of nitrate in grass with the subsequent reduction during the active growing season (Spring). The contents of nitrate and phosphorus in grass tissue are higher than those of grass in general pastureland, probably due to nutrient luxury uptake by grass. The overall grass yield, growth rate and nutrient uptake are quantified and implication of such high rate OLFS discussed.

  18. Nitrification, denitrification and biological phosphorus removal in piggery wastewater using a sequencing batch reactor.

    PubMed

    Obaja, D; Macé, S; Costa, J; Sans, C; Mata-Alvarez, J

    2003-03-01

    Nutrients in piggery wastewater with high organic matter, nitrogen (N) and phosphorus (P) content were biologically removed in a sequencing batch reactor (SBR) with anaerobic, aerobic and anoxic stages. The SBR was operated with 3 cycles/day, temperature 30 degrees C, sludge retention time (SRT) 1 day and hydraulic retention time (HRT) 11 days. With a wastewater containing 1500 mg/l ammonium and 144 mg/l phosphate, a removal efficiency of 99.7% for nitrogen and 97.3% for phosphate was obtained. Experiments set up to evaluate the effect of temperature on the process showed that it should be run at temperatures higher than 16 degrees C to obtain good removals (> 95%). Batch tests (ammonia utilization rate, nitrogen utilization rate and oxygen utilization rate) proved to be good tools to evaluate heterotrophic and autotrophic biomass activity. The SBR proved to be a very flexible tool, and was particularly suitable for the treatment of piggery wastewater, characterized by high nutrient content and by frequent changes in composition and therefore affecting process conditions.

  19. 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

  20. Simultaneous carbon and nitrogen removal in anoxic-aerobic circulating fluidized bed biological reactor (CFBBR).

    PubMed

    Cui, Y; Nakhla, G; Zhu, J; Patel, A

    2004-06-01

    Biological nutrient removal (BNR) in municipal wastewater treatment to remove carbonaceous substrates and nutrients, has recently become increasingly popular worldwide due to increasingly stringent regulations. Biological fluidized bed (BFB) technology, which could be potentially used for BNR, can provide some advantages such as high efficiency and a compact structure. This work shows the results of simultaneous elimination of organic carbon and nitrogen using a circulating fluidized bed biological reactor (CFBBR, which has been developed recently for chemical engineering processes. The CFBBR has two fluidized beds, running as anoxic and aerobic processes to accomplish simultaneous nitrification and denitrification, with continuous liquid recirculation through the anoxic bed and the aerobic bed. Soluble COD concentrations in the effluent ranging from 4 to 20 mg l(-1) were obtained at varying COD loading rates; ammonia nitrogen removal efficiencies averaged in excess of 99% at a minimum total hydraulic retention time (HRT) of 2.0 hours over a temperature range of 25 degrees C to 28 degrees C. Effluent nitrate nitrogen concentration of less than 5 mg l(-1) was achieved by increasing effluent recycle rate. No nitrite accumulation was observed either in the anoxic bed or in the aerobic bed. The system was able to treat grit chamber effluent wastewater at a HRT of 2.0 hours while achieving average effluent BOD, COD, NH3-N, TKN, nitrates, total phosphate, TSS and VSS concentrations of 10 mg l(-1), 18 mg l(-1), 1.3 mg l(-1), 1.5 mg l(-1), 7 mg l(-1), 2.0 mg l(-1), 10 mg l(-1) and 8 mg l(-1) respectively. The CFBBR appears to be not only an excellent alternative for conventional activated sludge type BNR technologies but also capable of processing much higher loadings that are suitable for industrial applications.

  1. Leaching techniques to remove metals and potentially hazardous nutrients from trout farm sludge.

    PubMed

    Jung, I S; Lovitt, R W

    2011-11-15

    A fish farm sludge high in P (2-6% w/w as dry matter), Fe (5-7%), C (40-50%) and N (0.8-4%) was subjected to a series of acid leaching treatments using HCl, organic acids, and biologically mediated acid production. Additions of biodegradable organic acid solubilized heavy metals better than HCl, while additions of 1.5% w/v glucose followed by 7 day incubation stabilized the sludge releasing 92% P, 100% Fe. The use of homo-lactic Lactobacillus plantarum starter cultures were more effective than hetero-lactic Lactobacillus buchneri, solubilizing 81.9% P, 92.2% Fe, 93.0% Zn and 96.4% Ca in the sludge. The anaerobic sludge-glucose fermentation using L. plantarum produced a leached sludge that has low heavy metal and nutrient content while affording the recovery of nutrients. The potential of these methods for practical application are briefly discussed.

  2. Effects of two different nutrient loads on microalgal production, nutrient removal and photosynthetic efficiency in pilot-scale wastewater high rate algal ponds.

    PubMed

    Sutherland, Donna L; Turnbull, Matthew H; Broady, Paul A; Craggs, Rupert J

    2014-12-01

    When wastewater treatment high rate algal ponds (HRAP) are coupled with resource recovery processes, such as biofuel production, short hydraulic retention times (HRTs) are often favoured to increase the microalgal biomass productivity. However, short HRT can result in increased nutrient load to the HRAP which may negatively impact on the performance of the microalgae. This paper investigate the effects of high (NH4-N mean concentration 39.7 ± 17.9 g m(-3)) and moderate ((NH4-N mean concentration 19.9 ± 8.9 g m(-3)) nutrient loads and short HRT on the performance of microalgae with respect to light absorption, photosynthesis, biomass production and nutrient removal in pilot-scale (total volume 8 m(3)) wastewater treatment HRAPs. Microalgal biomass productivity was significantly higher under high nutrient loads, with a 133% and 126% increase in the chlorophyll-a and VSS areal productivities, respectively. Microalgae were more efficient at assimilating NH4-N from the wastewater under higher nutrient loads compared to moderate loads. Higher microalgal biomass with increased nutrient load resulted in increased light attenuation in the HRAP and lower light absorption efficiency by the microalgae. High nutrient loads also resulted in improved photosynthetic performance with significantly higher maximum rates of electron transport, oxygen production and quantum yield. This experiment demonstrated that microalgal productivity and nutrient removal efficiency were not inhibited by high nutrient loads, however, higher loads resulted in lower water quality in effluent discharge.

  3. Dissolved nutrients and atrazine removal by column-scale monophasic and biphasic rain garden model systems.

    PubMed

    Yang, Hanbae; McCoy, Edward L; Grewal, Parwinder S; Dick, Warren A

    2010-08-01

    Rain gardens are bioretention systems that have the potential to reduce peak runoff flow and improve water quality in a natural and aesthetically pleasing manner. We compared hydraulic performance and removal efficiencies of nutrients and atrazine in a monophasic rain garden design versus a biphasic design at a column-scale using simulated runoff. The biphasic rain garden was designed to increase retention time and removal efficiency of runoff pollutants by creating a sequence of water saturated to unsaturated conditions. We also evaluated the effect of C substrate availability on pollutant removal efficiency in the biphasic rain garden. Five simulated runoff events with various concentrations of runoff pollutants (i.e. nitrate, phosphate, and atrazine) were applied to the monophasic and biphasic rain gardens once every 5d. Hydraulic performance was consistent over the five simulated runoff events. Peak flow was reduced by approximately 56% for the monophasic design and 80% for the biphasic design. Both rain garden systems showed excellent removal efficiency of phosphate (89-100%) and atrazine (84-100%). However, significantly (p<0.001) higher removal of nitrate was observed in the biphasic (42-63%) compared to the monophasic rain garden (29-39%). Addition of C substrate in the form of glucose increased removal efficiency of nitrate significantly (p<0.001), achieving up to 87% removal at a treatment C/N ratio of 2.0. This study demonstrates the importance of retention time, environmental conditions (i.e. saturated/unsaturated conditions), and availability of C substrate for bioremediation of pollutants, especially nitrates, in rain gardens.

  4. Nitrification and microalgae cultivation for two-stage biological nutrient valorization from source separated urine.

    PubMed

    Coppens, Joeri; Lindeboom, Ralph; Muys, Maarten; Coessens, Wout; Alloul, Abbas; Meerbergen, Ken; Lievens, Bart; Clauwaert, Peter; Boon, Nico; Vlaeminck, Siegfried E

    2016-07-01

    Urine contains the majority of nutrients in urban wastewaters and is an ideal nutrient recovery target. In this study, stabilization of real undiluted urine through nitrification and subsequent microalgae cultivation were explored as strategy for biological nutrient recovery. A nitrifying inoculum screening revealed a commercial aquaculture inoculum to have the highest halotolerance. This inoculum was compared with municipal activated sludge for the start-up of two nitrification membrane bioreactors. Complete nitrification of undiluted urine was achieved in both systems at a conductivity of 75mScm(-1) and loading rate above 450mgNL(-1)d(-1). The halotolerant inoculum shortened the start-up time with 54%. Nitrite oxidizers showed faster salt adaptation and Nitrobacter spp. became the dominant nitrite oxidizers. Nitrified urine as growth medium for Arthrospira platensis demonstrated superior growth compared to untreated urine and resulted in a high protein content of 62%. This two-stage strategy is therefore a promising approach for biological nutrient recovery.

  5. Assessment of the nutrient removal effectiveness of floating treatment wetlands applied to urban retention ponds.

    PubMed

    Wang, Chih-Yu; Sample, David J

    2014-05-01

    The application of floating treatment wetlands (FTWs) in point and non-point source pollution control has received much attention recently. Although the potential of this emerging technology is supported by various studies, quantifying FTW performance in urban retention ponds remains elusive due to significant research gaps. Actual urban retention pond water was utilized in this mesocosm study to evaluate phosphorus and nitrogen removal efficiency of FTWs. Multiple treatments were used to investigate the contribution of each component in the FTW system with a seven-day retention time. The four treatments included a control, floating mat, pickerelweed (Pontederia cordata L.), and softstem bulrush (Schoenoplectus tabernaemontani). The water samples collected on Day 0 (initial) and 7 were analyzed for total phosphorus (TP), total particulate phosphorus, orthophosphate, total nitrogen (TN), organic nitrogen, ammonia nitrogen, nitrate-nitrite nitrogen, and chlorophyll-a. Statistical tests were used to evaluate the differences between the four treatments. The effects of temperature on TP and TN removal rates of the FTWs were described by the modified Arrhenius equation. Our results indicated that all three FTW designs, planted and unplanted floating mats, could significantly improve phosphorus and nitrogen removal efficiency (%, E-TP and E-TN) compared to the control treatment during the growing season, i.e., May through August. The E-TP and E-TN was enhanced by 8.2% and 18.2% in the FTW treatments planted with the pickerelweed and softstem bulrush, respectively. Organic matter decomposition was likely to be the primary contributor of nutrient removal by FTWs in urban retention ponds. Such a mechanism is fostered by microbes within the attached biofilms on the floating mats and plant root surfaces. Among the results of the four treatments, the FTWs planted with pickerelweed had the highest E-TP, and behaved similarly with the other two FTW treatments for nitrogen removal

  6. 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

  7. Including Life Cycle Assessment for decision-making in controlling wastewater nutrient removal systems.

    PubMed

    Corominas, Lluís; Larsen, Henrik F; Flores-Alsina, Xavier; Vanrolleghem, Peter A

    2013-10-15

    This paper focuses on the use of Life Cycle Assessment (LCA) to evaluate the performance of seventeen control strategies in wastewater treatment plants (WWTPs). It tackles the importance of using site-specific factors for nutrient enrichment when decision-makers have to select best operating strategies. Therefore, the LCA evaluation is repeated for three different scenarios depending on the limitation of nitrogen (N), phosphorus (P), or both, when evaluating the nutrient enrichment impact in water bodies. The LCA results indicate that for treated effluent discharged into N-deficient aquatic systems (e.g. open coastal areas) the most eco-friendly strategies differ from the ones dealing with discharging into P-deficient (e.g. lakes and rivers) and N&P-deficient systems (e.g. coastal zones). More particularly, the results suggest that strategies that promote increased nutrient removal and/or energy savings present an environmental benefit for N&P and P-deficient systems. This is not the case when addressing N-deficient systems for which the use of chemicals (even for improving N removal efficiencies) is not always beneficial for the environment. A sensitivity analysis on using weighting of the impact categories is conducted to assess how value choices (policy decisions) may affect the management of WWTPs. For the scenarios with only N-limitation, the LCA-based ranking of the control strategies is sensitive to the choice of weighting factors, whereas this is not the case for N&P or P-deficient aquatic systems.

  8. Cultivation of Chlorella vulgaris in wastewater with waste glycerol: Strategies for improving nutrients removal and enhancing lipid production.

    PubMed

    Ma, Xiaochen; Zheng, Hongli; Addy, Min; Anderson, Erik; Liu, Yuhuan; Chen, Paul; Ruan, Roger

    2016-05-01

    To improve nutrients removal from wastewater and enhance lipid production, cultivation of Chlorella vulgaris in wastewater with waste glycerol generated from biodiesel production using scum derived oil as feedstock was studied. The results showed that nutrients removal was improved and lipid production of C. vulgaris was enhanced with the addition of waste glycerol into wastewater to balance its C/N ratio. The optimal concentration of the pretreated glycerol for C. vulgaris was 10gL(-1) with biomass concentration of 2.92gL(-1), lipid productivity of 163mgL(-1)d(-1), and the removal of 100% ammonia and 95% of total nitrogen. Alkaline conditions prompted cell growth and lipid accumulation of C. vulgaris while stimulating nutrients removal. The application of the integration process can lower both wastewater treatment and biofuel feedstock costs.

  9. Simultaneous removal of nutrients from milking parlor wastewater using an AO2 sequencing batch reactor (SBR) system.

    PubMed

    Wu, Xiao; Zhu, Jun

    2015-01-01

    The feasibility of using a lab-scale, anaerobic-aerobic-anoxic-aerobic sequencing batch reactor ((AO)2 SBR) to simultaneously remove biological organics, nitrogen and phosphorus from dairy milking parlor wastewater was investigated in this study. Three hydraulic retention times (HRT = 2.1, 2.7, and 3.5 days) and three mixing-to-process time ratios (TM/TP = 0.43, 0.57, and 0.68) were evaluated as two controlling factors using a 3 × 3 experimental design to determine the optimal combination. Results showed that the HRT of 2.7 days with TM/TP = 0.57 was the best to achieve simultaneous nutrients removal for the influent with initial soluble chemical oxygen demand (SCOD) of about 2000 mg L(-1) (only 0.55 mg L(-1) NH4-N, < 0.1 mg L(-1) nitrate, and 0.14 mg L(-1) soluble phosphorus in the effluent). Good correlations between pH and ORP, and ORP and DO, were also obtained with correlation coefficients all higher than or equal to 0.975. These relationships could be used to develop real-time control strategies to optimize the duration of each operating phase in the (AO)2 SBR system to save energy and enhance treatment efficiency.

  10. 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 (PO4-P) and ammonia nitrogen (NH4-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.

  11. Biological removal of dimethyl sulphide from sea water

    NASA Astrophysics Data System (ADS)

    Kiene, Ronald P.; Bates, Timothy S.

    1990-06-01

    DIMETHYL sulphide (DMS) is an important sulphur-containing trace gas in the atmosphere. It is present in oceanic surface waters at concentrations sufficient to sustain a considerable net flux of DMS from the oceans to the atmosphere, estimated to comprise nearly half of the global biogenic input of sulphur to the atmosphere1. DMS emitted from the oceans may be a precursor of tropospheric aerosols and of cloud condensation nuclei in the remote marine atmosphere, thereby affecting the Earth's radiative balance and thus its climate2-4. Relatively little is known, however, about the biogeochemical and physical processes that control the concentration of DMS in sea water. Here we present data from incubation experiments, carried out at sea, which show that DMS is removed by microbial activity. In the eastern, tropical Pacific Ocean, DMS turnover is dominated by biological processes, with turnover times for biological DMS removal generally more than ten (3-430) times faster than turnover by ventilation to the atmosphere. Thus biological consumption of DMS seems to be a more important factor than atmospheric exchange in controlling DMS concentrations in the ocean, and hence its flux to the atmosphere. These results have significant implications for climate feedback models involving DMS emissions3, and highlight the importance of the microbial food web in oceanic DMS cycling.

  12. Southern Ocean nutrient trapping and the efficiency of the biological pump

    NASA Astrophysics Data System (ADS)

    Primeau, FrançOis W.; Holzer, Mark; Devries, Timothy

    2013-05-01

    We present a data-assimilated model of the ocean's phosphorus cycle that is constrained by climatological phosphate, temperature, salinity, sea-surface height, surface heat and freshwater fluxes, as well as chlorofluorocarbon-11(CFC-11) and natural Δ14C. Export production is estimated to be 5.8±2.0×1012 mol P/yr of which (26±6)% originates in the Southern Ocean (SO) south of 40°S. The biological pump efficiency, defined as the proportion of the ocean's phosphate inventory that is regenerated, is (39±7)%. Dividing the SO south of 40°S into a sub-Antarctic zone (SANTZ) and an Antarctic zone (ANTZ) separated by the latitude of maximum Ekman divergence, we estimate that the SANTZ and ANTZ account, respectively, for (23±5)% and (3±1)% of global export production, (17±4)% and (3±1)% of the regenerated nutrient inventory, and (31±1)% and (43±5)% of the preformed nutrient inventory. Idealized SO nutrient depletion experiments reveal a large-scale transfer of nutrients into circumpolar and deep waters and from the preformed to the regenerated pool. In accord with the concept of the biogeochemical divide, we find that nutrient drawdown in the ANTZ is more effective than in the SANTZ for increasing the efficiency of the biological pump, while having a smaller impact on production in regions north of 40°S. Complete SO nutrient drawdown would allow the biological pump to operate at 94% efficiency by short circuiting the transport of nutrients in northward Ekman currents, leading to a trapping of nutrients in circumpolar and deep waters that would decrease production outside the SO by approximately 44% while increasing it in the SO by more than 725%.

  13. Bacterial removal and protozoan grazing in biological sand filters.

    PubMed

    Bomo, Anne-Marie; Stevik, Tor Kristian; Hovi, Ine; Hanssen, Jon Fredrik

    2004-01-01

    The objective of the study was to investigate the importance of protozoan predation as a biological removal mechanism in sand filters used for purification of bacteria from wastewater. Eleven sand filter columns were seeded with a high dose of wastewater (70 mm d(-1)) and a high concentration (10(8) colony forming units [CFU] mL(-1)) of Aeromonas hydrophila (American Type Culture Collection [ATCC] 14715) for a period of 30 d. Water samples from three filter outlets were analyzed for the concentration of A. hydrophila. In addition, one filter column was sacrificed each sampling day for the quantification of A. hydrophila, culturable bacteria (heterotrophic plate counts, HPC), total bacterial counts, and protozoa in the sand. The mean removal efficiency of A. hydrophila in the sand filter columns was 4.7 log units. The concentration of A. hydrophila in the sand filter effluent, however, had a clearly time-dependent pattern from high (log 6) and unstable concentrations to low and more stable levels (log 2). The removal efficiency of A. hydrophila correlated significantly (P = 0.0005, r2 = 0.6) with numbers of protozoa in the sand filters. Significantly higher (P < 0.05) concentrations of A. hydrophila were observed in sand filter effluents from columns treated with the protozoan inhibitor cycloheximide, compared with nontreated columns. Results from the present study show that protozoan grazing plays an important role as a bacterial removal mechanism in sand infiltration systems.

  14. Atrazine removal from aqueous solutions using submerged biological aerated filter

    PubMed Central

    2013-01-01

    Atrazine is widely used in the agriculture as an herbicide. Due to its high mobility, Atrazine leaks into the groundwaters, surface waters, and drinking water wells. Many physical and chemical methods have been suggested for removing Atrazine from aquatic environments. However, these methods are very costly, have many performance problems, produce a lot of toxic intermediates which are very harmful and dangerous, and cannot completely mineralize Atrazine. In this study, biodegradation of Atrazine by microbial consortium was evaluated in the aquatic environment. In order to assess the Atrazine removal from the aquatic environment, submerged biological aerated filter (SBAF) was fed with synthetic wastewater based on sucrose and Atrazine at different hydraulic retention times (HRTs). The maximum efficiencies for Atrazine and Soluble Chemical Oxygen Demand (SCOD) removal were 97.9% and 98.9%, respectively. The study findings showed that Stover-Kincannon model had very good fitness (R2 > 99%) in loading Atrazine in the biofilter and by increasing the initial concentration of Atrazine, the removal efficiency increased. Aerobic mixed biofilm culture was observed to be suitable for the treatment of Atrazine from aquatic environment. There was no significant inhibition effect on mixed aerobic microbial consortia. Atrazine degradation depended on the strength of wastewater and the amount of Atrazine in the influent. PMID:24499572

  15. Water treatment by aquatic ecosystem: Nutrient removal by reservoirs and flooded fields

    NASA Astrophysics Data System (ADS)

    Reddy, K. R.; Sacco, P. D.; Graetz, D. A.; Campbell, K. L.; Sinclair, L. R.

    1982-05-01

    Potential use of reservoirs and flooded fields stocked with aquatic plants for reduction of the nutrient levels of organic soil drainage water was evaluated. The treatment systems include 1) a large single reservoir (R1) stocked with waterhyacinth ( Eichhornia crassipes), elodea ( Egeria densa), and cattails ( Typha sp.) in series; 2) three small reservoirs in series with waterhyacinth (R2), elodea (R3), and cattails (R4), grown in independent reservoirs; 3) a control reservoir (R5) with no cultivated plants; 4) a large single flooded field planted to cattails; 5) three small flooded fields in a series planted to cattails; and 6) a flooded field with no cultivated plants. Drainage water was pumped daily (6 hours a day, and 6 days a week) into these systems for a period of 27 months at predetermined constant flow rates. Water samples were collected at the inlet and outlet of each treatment system and analyzed for N and P forms. The series of reservoirs stocked with aquatic plants functioned effectively in the removal of N and P from agricultural drainage water, compared to a single large reservoir. Allowing the water to flow through the reservoir stocked with waterhyacinth plants with a residence time of 3.6 days was adequate to remove about 50% of the incoming inorganic N. Allowing the water to flow through a series of two small reservoirs, R2 and R3, with a residence time of 7.3 days was necessary to remove about 60% of the incoming ortho-P. Flooded fields were effective in the removal of inorganic N, but showed poor efficiency in the removal of ortho-P.

  16. Removal of nutrients from undiluted anaerobically treated piggery wastewater by improved microalgae.

    PubMed

    Wang, Mingzi; Yang, Yi; Chen, Zhihong; Chen, Yanzhen; Wen, Yangmin; Chen, Bilian

    2016-12-01

    This study aimed at improving the adaptability and biodegradability of tested microalgae in undiluted anaerobic fermentation slurry of piggery wastewater. For that, a two-stage method based on UV irradiation followed by gradual domestication was developed. The distinctness of this method was the elimination of a screening procedure and just needed the UV-irradiated cells with appropriate survival to be subjected to gradual domestication. The microalgae treated with the method not only grew well in undiluted slurry, but achieved outstanding removal efficiencies in total nitrogen (TN) and total phosphorus (TP). Large-scale application was conducted in an open raceway pond, and the concentrations of TN and TP after treatment were 43.80mg/L (removal rate of 89.5%) and 5.83mg/L (removal rate of 85.3%) respectively, which greatly excelled the Chinese discharge standards for livestock and poultry wastewater. The strategy is therefore a promising method for microalgae to purify piggery slurry containing high nutrient contents.

  17. Enhanced nitrogen and phosphorus removal by an advanced simultaneous sludge reduction, inorganic solids separation, phosphorus recovery, and enhanced nutrient removal wastewater treatment process.

    PubMed

    Yan, Peng; Guo, Jin-Song; Wang, Jing; Chen, You-Peng; Ji, Fang-Ying; Dong, Yang; Zhang, Hong; Ouyang, Wen-juan

    2015-05-01

    An advanced wastewater treatment process (SIPER) was developed to simultaneously decrease sludge production, prevent the accumulation of inorganic solids, recover phosphorus, and enhance nutrient removal. The feasibility of simultaneous enhanced nutrient removal along with sludge reduction as well as the potential for enhanced nutrient removal via this process were further evaluated. The results showed that the denitrification potential of the supernatant of alkaline-treated sludge was higher than that of the influent. The system COD and VFA were increased by 23.0% and 68.2%, respectively, after the return of alkaline-treated sludge as an internal C-source, and the internal C-source contributed 24.1% of the total C-source. A total of 74.5% of phosphorus from wastewater was recovered as a usable chemical crystalline product. The nitrogen and phosphorus removal were improved by 19.6% and 23.6%, respectively, after incorporation of the side-stream system. Sludge minimization and excellent nutrient removal were successfully coupled in the SIPER process.

  18. Removal of Biologically Active Organic Contaminants using Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Banks, Michael A. (Inventor); Banks, Eric B. (Inventor)

    2003-01-01

    Biomedical devices that are to come into contact with living tissue, such as prosthetic and other implants for the human body and the containers used to store and transport them, are together cleaned of non-living, but biologically active organic materials, including endotoxins such as lipopolysaccharides, and assembled into a hermetically sealed package without recontamination. This is achieved by cleaning both the device and package components together in an apparatus, which includes a hermetically sealed chamber, in which they are contacted with atomic oxygen which biocleans them, by oxidizing the biologically active organic materials. The apparatus also includes means for manipulating the device and container and hermetically sealing the cleaned device into the cleaned container to form the package. A calibrated witness coupon visually indicates whether or not the device and container have received enough exposure to the atomic oxygen to have removed the organic materials from their surfaces. Gamma radiation is then used to sterilize the device in the sealed container.

  19. 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

    2017-03-22

    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.

  20. 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.

  1. Kinetic start-up performance of two large treatment plants for nutrient removal.

    PubMed

    Haarbo, A; Harremoës, P; Thirsing, C

    2001-01-01

    In 1987 an action plan was passed in the Danish Parliament demanding a considerable reduction of the discharge of nutrients to the aquatic environment in Denmark. Consequently, the two largest wastewater treatment plants in the Copenhagen area had to be upgraded to include nutrient removal. For more than 8 years an extensive effort has been made to determine an optimum solution for this upgrading from a technical and financial point of view. The work included six years of comprehensive pilot plant investigations with the aim of thoroughly studying and interpreting the kinetics of the processes involved. The investigations revealed valuable information particularly concerning limitations of the nitrification process. Consequently, the investigations contributed to an expectation of no unforeseen problems during the implementation of the upgraded plants. This paper presents the results of the start-up of the two full-scale plants with the main emphasis laid on the kinetic performance in relation to the information achieved from the pilot tests. The results showed that the start-up of the full scale plants proceeded with great accuracy as expected from the investigations. Accordingly, the implementation of the plants was carried out successfully, ending an era of more than 10 years in total.

  2. Physical, Nutrient, and Biological Measurements of Coastal Waters off Central California in March 2012

    DTIC Science & Technology

    2012-10-01

    with accession #0098772. 15. SUBJECT TERMS hydrography, physical oceanography, biological oceanography, nutrients, zooplankton , PaCOOS, CalCOFI 16...List of Tables List of Figures Introduction Standard Procedures CTD/Rosette Data Zooplankton Net Tows... Zooplankton volume displacements for Bongo net samples collected during the PaCOOS cruise of March 2012 along CalCOFI line 67. Contours of

  3. Biological removal of cationic fission products from nuclear wastewater.

    PubMed

    Ngwenya, N; Chirwa, E M N

    2011-01-01

    Nuclear energy is becoming a preferred energy source amidst rising concerns over the impacts of fossil fuel based energy on global warming and climate change. However, the radioactive waste generated during nuclear power generation contains harmful long-lived fission products such as strontium (Sr). In this study, cationic strontium uptake from solution by microbial cultures obtained from mine wastewater is evaluated. A high strontium removal capacity (q(max)) with maximum loading of 444 mg/g biomass was achieved by a mixed sulphate reducing bacteria (SRB) culture. Sr removal in SRB was facilitated by cell surface based electrostatic interactions with the formation of weak ionic bonds, as 68% of the adsorbed Sr(2+) was easily desorbed from the biomass in an ion exchange reaction with MgCl₂. To a lesser extent, precipitation reactions were also found to account for the removal of Sr from aqueous solution as about 3% of the sorbed Sr was precipitated due to the presence of chemical ligands while the remainder occurred as an immobile fraction. Further analysis of the Sr-loaded SRB biomass by scanning electron microscopy (SEM) coupled to energy dispersive X-ray (EDX) confirmed extracellular Sr(2+) precipitation as a result of chemical interaction. In summary, the obtained results demonstrate the prospects of using biological technologies for the remediation of industrial wastewaters contaminated by fission products.

  4. Enhanced biological phosphorus removal with different carbon sources.

    PubMed

    Shen, Nan; Zhou, Yan

    2016-06-01

    Enhanced biological phosphorus removal (EBPR) process is one of the most economical and sustainable methods for phosphorus removal from wastewater. However, the performance of EBPR can be affected by available carbon sources types in the wastewater that may induce different functional microbial communities in the process. Glycogen accumulating organisms (GAOs) and polyphosphate accumulating organisms (PAOs) are commonly found by coexisting in the EBPR process. Predominance of GAO population may lead to EBPR failure due to the competition on carbon source with PAO without contributing phosphorus removal. Carbon sources indeed play an important role in alteration of PAOs and GAOs in EBPR processes. Various types of carbon sources have been investigated for EBPR performance. Certain carbon sources tend to enrich specific groups of GAOs and/or PAOs. This review summarizes the types of carbon sources applied in EBPR systems and highlights the roles of these carbon sources in PAO and GAO competition. Both single (e.g., acetate, propionate, glucose, ethanol, and amino acid) and complex carbon sources (e.g., yeast extract, peptone, and mixed carbon sources) are discussed in this review. Meanwhile, the environmental friendly and economical carbon sources that are derived from waste materials, such as crude glycerol and wasted sludge, are also discussed and compared.

  5. Biological nitrate removal using a food waste-derived carbon source in synthetic wastewater and real sewage.

    PubMed

    Zhang, Haowei; Jiang, Jianguo; Li, Menglu; Yan, Feng; Gong, Changxiu; Wang, Quan

    2016-01-15

    The production of volatile fatty acids (VFAs) from food waste to improve biological nutrient removal has drawn much attention. In this study, acidogenic liquid from food waste was used as an alternative carbon source for synthetic wastewater treatment. C/N ratios of 5 and 6 were suitable for denitrification, and the change in acidogenic liquid composition had no negative effect on denitrification. The denitrification rates using optimal carbon-to-nitrate ratios of acidogenic liquid were more than 25 mg NO3-N/(gVSS·h). At the same time, acidogenic liquid was used to improve nutrient removal from summer and winter sewage. C/N ratios of 5 and 6 were acceptable for summer sewage treatment. Total nitrogen in the final effluent was less than 7 mg/L. Two additional hours were required for winter sewage treatment, and the C/N ratio had to be >6.

  6. Phosphorus removal in an enhanced biological phosphorus removal process: roles of extracellular polymeric substances.

    PubMed

    Zhang, Hai-Ling; Fang, Wei; Wang, Yong-Peng; Sheng, Guo-Ping; Zeng, Raymond J; Li, Wen-Wei; Yu, Han-Qing

    2013-10-15

    Phosphorus-accumulating organisms are considered to be the key microorganisms in the enhanced biological phosphorus removal (EBPR) process. A large amount of phosphorus is found in the extracellular polymeric substances (EPS) matrix of these microorganisms. However, the roles of EPS in phosphorus removal have not been fully understood. In this study, the phosphorus in the EBPR sludge was fractionated and further analyzed using quantitative (31)P nuclear magnetic resonance spectroscopy. The amounts and forms of phosphorus in EPS as well as their changes in an anaerobic-aerobic process were also investigated. EPS could act as a reservoir for phosphorus in the anaerobic-aerobic process. About 5-9% of phosphorus in sludge was reserved in the EPS at the end of the aerobic phase and might further contribute to the phosphorus removal. The chain length of the intracellular long-chain polyphosphate (polyP) decreased in the anaerobic phase and then recovered under aerobic conditions. However, the polyP in the EPS had a much shorter chain length than the intracellular polyP in the whole cycle. The migration and transformation of various forms of phosphorus among microbial cells, EPS, and bulk liquid were also explored. On the basis of these results, a model with a consideration of the roles of EPS was proposed, which is beneficial to elucidate the mechanism of phosphorus removal in the EBPR system.

  7. Transport of biologically important nutrients by wind in an eroding cold desert

    USGS Publications Warehouse

    Sankey, Joel B.; Germino, Matthew J.; Benner, Shawn G.; Glenn, Nancy F.; Hoover, Amber N.

    2012-01-01

    Wind erosion following fire is an important landscape process that can result in the redistribution of ecologically important soil resources. In this study we evaluated the potential for a fire patch in a desert shrubland to serve as a source of biologically important nutrients to the adjacent, downwind, unburned ecosystem. We analyzed nutrient concentrations (P, K, Ca, Mg, Cu, Fe, Mn, Al) in wind-transported sediments, and soils from burned and adjacent unburned surfaces, collected during the first to second growing seasons after a wildfire that burned in 2007 in Idaho, USA in sagebrush steppe; a type of cold desert shrubland. We also evaluated the timing of potential wind erosion events and weather conditions that might have contributed to nutrient availability in downwind shrubland. Findings indicated that post-fire wind erosion resulted in an important, but transient, addition of nutrients on the downwind shrubland. Aeolian sediments from the burned area were enriched relative to both the up- and down-wind soil and indicated the potential for a fertilization effect through the deposition of the nutrient-enriched sediment during the first, but not second, summer after wildfire. Weather conditions that could have produced nutrient transport events might have provided increased soil moisture necessary to make nutrients accessible for plants in the desert environment. Wind transport of nutrients following fire is likely important in the sagebrush steppe as it could contribute to pulses of resource availability that might, for example, affect plant species differently depending on their phenology, and nutrient- and water-use requirements.

  8. Biological sulfate removal from gypsum contaminated construction and demolition debris.

    PubMed

    Kijjanapanich, Pimluck; Annachhatre, Ajit P; Esposito, Giovanni; van Hullebusch, Eric D; Lens, Piet N L

    2013-12-15

    Construction and demolition debris (CDD) contains high levels of sulfate that can cause detrimental environmental impacts when disposed without adequate treatment. In landfills, sulfate can be converted to hydrogen sulfide under anaerobic conditions. CDD can thus cause health impacts or odor problems to landfill employees and surrounding residents. Reduction of the sulfate content of CDD is an option to overcome these problems. This study aimed at developing a biological sulfate removal system to reduce the sulfate content of gypsum contaminated CDD in order to decrease the amount of solid waste, to improve the quality of CDD waste for recycling purposes and to recover sulfur from CDD. The treatment leached out the gypsum contained in CDD by water in a leaching column. The sulfate loaded leachate was then treated in a biological sulfate reducing Upflow Anaerobic Sludge Blanket (UASB) reactor to convert the sulfate to sulfide. The UASB reactor was operated at 23 ± 3 °C with a hydraulic retention time and upflow velocity of 15.5 h and 0.1 m h(-1), respectively while ethanol was added as electron donor at a final organic loading rate of 3.46 g COD L(-1) reactor d(-1). The CDD leachate had a pH of 8-9 and sulfate dissolution rates of 526.4 and 609.8 mg L(-1) d(-1) were achieved in CDD gypsum and CDD sand, respectively. Besides, it was observed that the gypsum dissolution was the rate limiting step for the biological treatment of CDD. The sulfate removal efficiency of the system stabilized at around 85%, enabling the reuse of the UASB effluent for the leaching step, proving the versatility of the bioreactor for practical applications.

  9. Combined carbonaceous removal and nitrification with biological aerated filters.

    PubMed

    Belgiorno, Vincenzo; De Feo, Giovanni; Napoli, Rodolfo M A

    2003-01-01

    This paper describes the use of a submerged biological aerated filter (BAFs), on a pilot plant scale, in the secondary nitrification of low strength domestic wastewater. The results, obtained throughout three months of tests, confirmed the ability of BAFs to obtain simultaneous carbonaceous removal and nitrification. In fact, alter a start-up period of 5 weeks, a remarkable steady state condition in the removal of suspended solids (TSS), chemical oxygen demand (COD) and nitrification was reached. For a hydraulic loading rate of 1.6 m3 m(-2) h(-1), the mean efficiency of the process in the removal of TSS and COD was 85% and 83% respectively. Mean concentrations in the influent flow of around 114 mg(TSS)/L and 140 mg(COD)/L were reduced to average values of below 17 mg(TSS)/L and 25 mg(COD)/L. Secondary nitrification was achieved with a mean efficiency of 85% for a mean volumetric loads of 0.45 kg(N-Namm) m(-3) d(-1) (25 degrees C). Through an intensive activity of nitrification, in the steady state condition, mean influent concentrations of around 12 mg(N-Namm)/L were reduced to average values of below 2 mg(N-Namm)/L. The removal loading rate increased linearly with the applied loading rate for volumetric loads of up to 0.7 kg(N-Namm) m(-3) d(-1). The nitrification was not sensitive to the applied COD loads because of the low level of carbon substrate.

  10. Identification and characterization of a freshwater microalga Scenedesmus SDEC-8 for nutrient removal and biodiesel production.

    PubMed

    Song, Mingming; Pei, Haiyan; Hu, Wenrong; Zhang, Shuo; Ma, Guixia; Han, Lin; Ji, Yan

    2014-06-01

    The selection of the right strains is of fundamental important to the success of the algae-based oil industry. From the six newly isolated microalgae strains tested for growth, fatty acid methyl ester (FAME) profiles and biodiesel properties, Scenedesmus SDEC-8, with favorable C16:0 fatty acids (73.43%), showed the best combined results. Then, morphological and molecular identification were examined. From the three wastewaters samples, Scenedesmus SDEC-8 showed good ability to yield oil and remove nutrients, which were comparable with other reports. In b artificial wastewater (TN 40 mg L(-1), TP 8 mg L(-1)), Scenedesmus SDEC-8 achieved the highest value of lipid productivity (53.84 mg L(-1) d(-1)), MUFA content (35.35%) and total FAME content (59.57±0.02 mg g(-1) DW), besides higher removal efficiencies of TN (99.18%) and TP (98.86%) helped effluent directly discharge and smaller dilution factor of N, P (3.3 and 9) which was good for lessening water utilization.

  11. Root features related to plant growth and nutrient removal of 35 wetland plants.

    PubMed

    Lai, Wen-Ling; Wang, Shu-Qiang; Peng, Chang-Lian; Chen, Zhang-He

    2011-07-01

    Morphological, structural, and eco-physiological features of roots, nutrient removal, and correlation between the indices were comparatively studied for 35 emergent wetland plants in small-scale wetlands for further investigation into the hypothesis of two types of wetland plant roots (Chen et al., 2004). Significant differences in root morphological, structural, and eco-physiological features were found among the 35 species. They were divided into two types: fibrous-root plants and thick-root plants. The fibrous-root plants had most or all roots of diameter (D) ≤ 1 mm. Roots of D > 1 mm also had many fine and long lateral roots of D ≤ 1 mm. The roots of these plants were long and had a thin epidermis and a low degree of lignification. The roots of the thick-root plants were almost all thicker than 1 mm, and generally had no further fine lateral roots. The roots were short, smooth, and fleshy, and had a thick epidermis. Root porosity of the fibrous-root plants was higher than that of the thick-root plants (p = 0.001). The aerenchyma of the fibrous-root plants was composed of large cavities which were formed from many small cavities, and distributed radially between the exodermis and vascular tissues. The aerenchyma of the thick-root plants had a large number of small cavities which were distributed in the mediopellis. The fibrous-root plants had a significantly larger root biomass of D ≤ 1 mm, of 1 mm < D < 3 mm, above-ground biomass, total biomass, and longer root system, but shorter root longevity than those of the thick-root plants (p = 0.003, 0.018, 0.020, 0.032, 0.042, 0.001). The fibrous-root plants also had significantly higher radial oxygen loss (ROL), root activity, photosynthetic rate, transpiration rate, and removal rates of total nitrogen and total phosphorus than the thick-root plants (p = 0.001, 0.008, 0.010, 0.004, 0.020, 0.002). The results indicate that significantly different root morphological and structural features existed among different

  12. Modelling biological and chemically induced precipitation of calcium phosphate in enhanced biological phosphorus removal systems.

    PubMed

    Barat, R; Montoya, T; Seco, A; Ferrer, J

    2011-06-01

    The biologically induced precipitation processes can be important in wastewater treatment, in particular treating raw wastewater with high calcium concentration combined with Enhanced Biological Phosphorus Removal. Currently, there is little information and experience in modelling jointly biological and chemical processes. This paper presents a calcium phosphate precipitation model and its inclusion in the Activated Sludge Model No 2d (ASM2d). The proposed precipitation model considers that aqueous phase reactions quickly achieve the chemical equilibrium and that aqueous-solid change is kinetically governed. The model was calibrated using data from four experiments in a Sequencing Batch Reactor (SBR) operated for EBPR and finally validated with two experiments. The precipitation model proposed was able to reproduce the dynamics of amorphous calcium phosphate (ACP) formation and later crystallization to hydroxyapatite (HAP) under different scenarios. The model successfully characterised the EBPR performance of the SBR, including the biological, physical and chemical processes.

  13. High-density spore production of a B. cereus aquaculture biological agent by nutrient supplementation.

    PubMed

    Lalloo, Rajesh; Maharajh, Dheepak; Görgens, Johann; Gardiner, Neil; Görgens, J F

    2009-05-01

    Previous studies have demonstrated the efficacy of our Bacillus cereus isolate (NRRL 100132) in reducing concentrations of nitrogenous wastes and inhibiting growth of fish pathogens. In vivo efficacy and tolerance to a range of physiological conditions in systems used to rear Cyprinus carpio make this isolate an excellent candidate for aquaculture applications. Production cost is an important consideration in development of commercially relevant biological products, and this study examines the optimization of nutrient supplementation, which has an impact on high-density production of spores by fermentation. Corn steep liquor (CSL) was identified as a lower cost and more effective nutrient source in comparison to conventional nutrient substrates, in particular yeast extract and nutrient broth. The improved sporulation performance of B. cereus could be related to the increased availability of free amino acids, carbohydrates, and minerals in CSL, which had a positive effect on sporulation efficiency. The impact of nutrient concentration on spore yield and productivity was modeled to develop a tool for optimization of nutrient concentration in fermentation. An excellent fit of the model was confirmed in laboratory fermentation studies. A cost comparison revealed that production using liquid phytase and ultrafiltered-treated CSL was less expensive than spray-dried CSL and supported cultivation of B. cereus spores at densities higher than 1 x 10(10) CFU ml(-1).

  14. Biomass production and nutrient removal by Chlorella sp. as affected by sludge liquor concentration.

    PubMed

    Åkerström, Anette M; Mortensen, Leiv M; Rusten, Bjørn; Gislerød, Hans Ragnar

    2014-11-01

    The use of microalgae for biomass production and nutrient removal from the reject water produced in the dewatering process of anaerobically digested sludge, sludge liquor, was investigated. The sludge liquor was characterized by a high content of total suspended solids (1590 mg L(-1)), a high nitrogen concentration (1210 mg L(-1)), and a low phosphorus concentration (28 mg L(-1)). Chlorella sp. was grown in sludge liquor diluted with wastewater treatment plant effluent water to different concentrations (12, 25, 40, 50, 70, and 100%) using batch mode. The environmental conditions were 25 °C, a continuous lightning of 115 μmol m(-2) s(-1), and a CO2 concentration of 3.0%. The highest biomass production (0.42-0.45 g dry weight L(-1) Day(-1)) was achieved at 40-50% sludge liquor, which was comparable to the production of the control culture grown with an artificial fertilizer. The biomass production was 0.12 and 0.26 g dry weight L(-1) Day(-1) at 12% and 100% sludge liquor, respectively. The percentage of nitrogen in the algal biomass increased from 3.6% in 12% sludge liquor and reached a saturation of ∼10% in concentrations with 50% sludge liquor and higher. The phosphorus content in the biomass increased linearly from 0.2 to 1.5% with increasing sludge liquor concentrations. The highest nitrogen removal rates by algal biosynthesis were 33.6-42.6 mg TN L(-1) Day(-1) at 40-70% sludge liquor, while the highest phosphorus removal rates were 3.1-4.1 mg TP L(-1) Day(-1) at 50-100% sludge liquor.

  15. Population dynamics of bacteria involved in enhanced biological phosphorus removal in Danish wastewater treatment plants.

    PubMed

    Mielczarek, Artur Tomasz; Nguyen, Hien Thi Thu; Nielsen, Jeppe Lund; Nielsen, Per Halkjær

    2013-03-15

    The enhanced biological phosphorus removal (EBPR) process is increasingly popular as a sustainable method for removal of phosphorus (P) from wastewater. This study consisted of a comprehensive three-year investigation of the identity and population dynamics of polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in 28 Danish municipal wastewater treatment plants with nutrient removal. Fluorescence in situ hybridization was applied to quantify ten probe-defined populations of PAO and GAO that in total constituted a large fraction (30% on average) of the entire microbial community targeted by the EUBmix probes. Two PAO genera, Accumulibacter and Tetrasphaera, were very abundant in all EBPR plants (average of 3.7% and 27% of all bacteria, respectively), and their abundance was relatively stable in the Danish full-scale plants without clear temporal variations. GAOs were occasionally present in some plants (Competibacter in 11 plants, Defluviicoccus in 6 plants) and were consistent in only a few plants. This shows that these were not core species in the EBPR communities. The total GAO abundance was always lower than that of Accumulibacter. In plants without EBPR design, the abundance of PAO and GAO was significantly lower. Competibacter correlated in general with high fraction of industrial wastewater. In specific plants Accumulibacter correlated with high C/P ratio of the wastewater and Tetrasphaera with high organic loading. Interestingly, the relative microbial composition of the PAO/GAO species was unique to each plant over time, which gives a characteristic plant-specific "fingerprint".

  16. Optimization of biological sulfide removal in a CSTR bioreactor.

    PubMed

    Roosta, Aliakbar; Jahanmiri, Abdolhossein; Mowla, Dariush; Niazi, Ali; Sotoodeh, Hamidreza

    2012-08-01

    In this study, biological sulfide removal from natural gas in a continuous bioreactor is investigated for estimation of the optimal operational parameters. According to the carried out reactions, sulfide can be converted to elemental sulfur, sulfate, thiosulfate, and polysulfide, of which elemental sulfur is the desired product. A mathematical model is developed and was used for investigation of the effect of various parameters on elemental sulfur selectivity. The results of the simulation show that elemental sulfur selectivity is a function of dissolved oxygen, sulfide load, pH, and concentration of bacteria. Optimal parameter values are calculated for maximum elemental sulfur selectivity by using genetic algorithm as an adaptive heuristic search. In the optimal conditions, 87.76% of sulfide loaded to the bioreactor is converted to elemental sulfur.

  17. Biological removal of carbon disulfide from waste air streams

    SciTech Connect

    Hugler, W.; Acosta, C.; Revah, S.

    1999-09-30

    A pilot-scale biological control system for the treatment of 3,400 m{sup 3} h{sup {minus}1} of a gaseous stream containing up to 7.8 g CS{sub 2} m{sup {minus}3} and trace amounts of hydrogen sulfide (H{sub 2}S) was installed in a cellulose sponge manufacturing facility. The objective was to demonstrate the capability of the process to attain sustained removal efficiencies of 90% for CS{sub 2} and 99% for H{sub 2}S. The system consisted of two sequential biotrickling reactors, which had been previously inoculated with an adapted microbial consortium. During the pilot test, stable removal efficiency and elimination capacity of +90% and 220g CS{sub 2} m{sup {minus}3} h{sup {minus}1}, respectively, were attained with an empty bed residence time (EBTR) of 33 seconds for a period of several weeks. Efficiencies greater than 99% were always obtained for H{sub 2}S. Based on the results, the system was determined to be an effective process to remediate waste air streams containing reduced sulfur compounds generated at cellulose sponge facilities.

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

    SciTech Connect

    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 the 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.

  19. A multiscale analysis of nutrient transport and biological tissue growth in vitro.

    PubMed

    O'Dea, R D; Nelson, M R; El Haj, A J; Waters, S L; Byrne, H M

    2015-09-01

    In this paper, we consider the derivation of macroscopic equations appropriate to describe the growth of biological tissue, employing a multiple-scale homogenization method to accommodate explicitly the influence of the underlying microscale structure of the material, and its evolution, on the macroscale dynamics. Such methods have been widely used to study porous and poroelastic materials; however, a distinguishing feature of biological tissue is its ability to remodel continuously in response to local environmental cues. Here, we present the derivation of a model broadly applicable to tissue engineering applications, characterized by cell proliferation and extracellular matrix deposition in porous scaffolds used within tissue culture systems, which we use to study coupling between fluid flow, nutrient transport, and microscale tissue growth. Attention is restricted to surface accretion within a rigid porous medium saturated with a Newtonian fluid; coupling between the various dynamics is achieved by specifying the rate of microscale growth to be dependent upon the uptake of a generic diffusible nutrient. The resulting macroscale model comprises a Darcy-type equation governing fluid flow, with flow characteristics dictated by the assumed periodic microstructure and surface growth rate of the porous medium, coupled to an advection-reaction equation specifying the nutrient concentration. Illustrative numerical simulations are presented to indicate the influence of microscale growth on macroscale dynamics, and to highlight the importance of including experimentally relevant microstructural information to correctly determine flow dynamics and nutrient delivery in tissue engineering applications.

  20. Biological response to millennial variability of dust and nutrient supply in the Subantarctic South Atlantic Ocean.

    PubMed

    Anderson, Robert F; Barker, Stephen; Fleisher, Martin; Gersonde, Rainer; Goldstein, Steven L; Kuhn, Gerhard; Mortyn, P Graham; Pahnke, Katharina; Sachs, Julian P

    2014-07-13

    Fluxes of lithogenic material and fluxes of three palaeo-productivity proxies (organic carbon, biogenic opal and alkenones) over the past 100,000 years were determined using the (230)Th-normalization method in three sediment cores from the Subantarctic South Atlantic Ocean. Features in the lithogenic flux record of each core correspond to similar features in the record of dust deposition in the EPICA Dome C ice core. Biogenic fluxes correlate with lithogenic fluxes in each sediment core. Our preferred interpretation is that South American dust, most probably from Patagonia, constitutes a major source of lithogenic material in Subantarctic South Atlantic sediments, and that past biological productivity in this region responded to variability in the supply of dust, probably due to biologically available iron carried by the dust. Greater nutrient supply as well as greater nutrient utilization (stimulated by dust) contributed to Subantarctic productivity during cold periods, in contrast to the region south of the Antarctic Polar Front (APF), where reduced nutrient supply during cold periods was the principal factor limiting productivity. The anti-phased patterns of productivity on opposite sides of the APF point to shifts in the physical supply of nutrients and to dust as cofactors regulating productivity in the Southern Ocean.

  1. 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.

  2. Influence of carbon sources on nutrient removal in A(2)/O-MBRs: Availability assessment of internal carbon source.

    PubMed

    Xu, Rongle; Fan, Yaobo; Wei, Yuansong; Wang, Yawei; Luo, Nan; Yang, Min; Yuan, Xing; Yu, Rong

    2016-10-01

    Both internal carbon source and some external carbon sources were used to improve the nutrient removal in Anaerobic-Anoxic-Oxic-Membrane Bioreactor (A(2)/O-MBRs), and their technical and cost analysis was investigated. The experimental results showed that the nutrient removals were improved by all the carbon source additions. The total nitrogen and phosphorus removal efficiency were higher in the experiments with external carbon source additions than that with internal carbon source addition. It was found that pathways of nitrogen and phosphorus transform were different dependent on different carbon source additions by the mass balance analysis. With external carbon source addition, the simultaneous nitrification and denitrification occurred in aerobic zone, and the P-uptake in aerobic phase was evident. Therefore, with addition of C-MHP (internal carbon source produced from sludge pretreatment by microwave-H2O2 process), the denitrification and phosphorus-uptake in anoxic zone was notable. Cost analysis showed that the unit nitrogen removal costs were 57.13CNY/kg N of C-acetate addition and 54.48CNY/kgN of C-MHP addition, respectively. The results indicated that the C-MHP has a good technical and economic feasibility to substitute external carbon sources partially for nutrient removal.

  3. 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.

  4. 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.

  5. Population dynamics of filamentous bacteria in Danish wastewater treatment plants with nutrient removal.

    PubMed

    Mielczarek, Artur Tomasz; Kragelund, Caroline; Eriksen, Poul Svante; Nielsen, Per Halkjær

    2012-08-01

    Bulking and foaming are two frequently occurring operational problems in activated sludge wastewater treatment plants, and these problems are mainly associated with excessive growth of filamentous bacteria. In this study, a comprehensive investigation of the identity and population dynamics of filamentous bacteria in 28 Danish municipal treatment plants with nutrient removal has been carried out over three years. Fluorescence in situ hybridization was applied to quantify more than twenty probe-defined populations of filamentous bacteria that in total constituted a large fraction of the entire microbial community, on average 24%. Despite the majority being present within the flocs, they occasionally caused settling problems in most of the plants. A low diversity of probe-defined filamentous bacteria was found in the plants with Microthrix and various species belonging to phylum Chloroflexi (e.g., type 0803 and type 0092) as the most abundant. Few other filamentous probe-defined species were found revealing a large similarity between the filamentous populations in the plants investigated. The composition of filamentous populations was stable in each plant with only minor changes in relative abundances observed during the three-year study period. The relative composition of the different species was unique to each plant giving a characteristic "fingerprint". Comprehensive statistical analyses of the presence and abundance of the filamentous organisms did not reveal many correlations with a particular plant design or process parameter.

  6. Removal of organic pollutants and nutrients from olive mill wastewater by a sand filter.

    PubMed

    Achak, M; Mandi, L; Ouazzani, N

    2009-06-01

    The aim of this work was to examine the performance of a sand filter in treating modern olive mill (OMW) effluents after dilution with domestic wastewater on a one-to-one basis. The experimental pilot consisted of a column of opaque PVC, and the sand filter was filled with 50 cm of sand and 10 cm of gravel in the top and the bottom of the filter. The alimentation (4 cm/day) was done sequentially following a 1 day wet/3 days dry cycle. The OMW effluent was very acidic with a pH of 4.12, and had high concentrations of phenolic compounds (7.2g/L) and total chemical oxygen demand (65 g/L). The percolation of the diluted OMW through the sand filters caused an increase in pH from 4.84 to 8.25 and a 90% removal of total suspended solids. The sand filter treatment also led to important reductions in organic matter (90% of total COD, 83% of dissolved COD and 92% of phenolic compounds) and nutrients (91% of Kjeldahl-nitrogen, 97% of ammonia-nitrogen, 99% of nitrate-nitrogen and 99% of phosphates). The flow rate became very low indicating clogging of the sand pores after 10 weeks. HPLC analysis of the diluted OMW before and after passage through the sand filter showed an important reduction in the toxic monomeric compounds after the treatment.

  7. A biological phosphorus removal potential test for wastewaters.

    PubMed

    Park, J K; Whang, L M; Wang, J C; Novotny, G

    2001-01-01

    A simple test was proposed to assess whether phosphorus in a wastewater can be removed using a biological phosphorus removal (BPR) process. The test includes the measurement of phosphorus release during 2 hours of the anaerobic stage in a batch reactor containing phosphorus-accumulating organisms (PAOs) and estimation of the effluent phosphorus concentration using biochemical relationships. The BPR potential test developed allowed for the successful evaluation of BPR feasibility for five wastewater samples. The BPR potential test was validated by comparing the test results with the effluent phosphorus concentrations measured in a sequencing batch reactor (SBR). An effluent phosphorus concentration of 1.9 mg P/L predicted for the BPR potential test performed was close to the effluent phosphorus concentration of 1.8 mg P/L obtained from an SBR on the same day. During the anaerobic stage, phosphorus release was significantly affected by the sludge concentration initially, but became insignificant after 2 hours. The initial sludge concentration affected the phosphorus release rate; thus, it is recommended that the BPR potential test be conducted at a target mixed liquor volatile suspended solids concentration. It is also recommended that the BPR potential test be conducted at the site where the PAO-containing sludge is available and the wastewater sample can be delivered at 4 degrees C in less than 24 hours. The PAOs in different sludges had almost identical phosphorus release after 2 hours; however, the characteristics of facultative bacteria in sludges affected the phosphorus release. If the wastewater is prefermented for at least 3 days before the BPR potential test, the amount of phosphorus released by various PAO-containing sludges is expected to be identical.

  8. Effect of wastewater-borne bacteria on algal growth and nutrients removal in wastewater-based algae cultivation system.

    PubMed

    Ma, Xiaochen; Zhou, Wenguang; Fu, Zongqiang; Cheng, Yanling; Min, Min; Liu, Yuhuan; Zhang, Yunkai; Chen, Paul; Ruan, Roger

    2014-09-01

    Centrate, a type of nutrient-rich municipal wastewater was used to determine the effect of wastewater-borne bacteria on algal growth and nutrients removal efficiency in this study. The characteristics of algal and bacterial growth profiles, wastewater nutrient removal and effect of initial algal inoculums were systematically examined. The results showed that initial algal concentration had apparent effect on bacterial growth, and the presence of bacteria had a significant influence on algal growth pattern, suggesting symbiotic relationship between algae and bacteria at the initial stage of algae cultivation. The maximum algal biomass of 2.01 g/L with 0.1g/L initial algal inoculums concentration can be obtained during algae cultivation in raw centrate medium. The synergistic effect of centrate-borne bacteria and microalgae on algae growth and nutrient removal performance at initial fast growth stage has great potential to be applied to pilot-scale wastewater-based algae wastewater system cultivated in continuous or semi-continuous mode.

  9. From Earth to Space: Application of Biological Treatment for the Removal of Ammonia from Water

    NASA Technical Reports Server (NTRS)

    Pickering, Karen; Adam, Niklas; White, Dawn; Ghosh, Amlan; Seidel, Chad

    2014-01-01

    Managing ammonia is often a challenge in both drinking water and wastewater treatment facilities. Ammonia is unregulated in drinking water, but its presence may result in numerous water quality issues in the distribution system such as loss of residual disinfectant, nitrification, and corrosion. Ammonia concentrations need to be managed in wastewater effluent to sustain the health of receiving water bodies. Biological treatment involves the microbiological oxidation of ammonia to nitrate through a two-step process. While nitrification is common in the environment, and nitrifying bacteria can grow rapidly on filtration media, appropriate conditions, such as the presence of dissolved oxygen and required nutrients, need to be established. This presentation will highlight results from two ongoing research programs - one at NASA's Johnson Space Center, and the other at a drinking water facility in California. Both programs are designed to demonstrate nitrification through biological treatment. The objective of NASA's research is to be able to recycle wastewater to potable water for spaceflight missions. To this end, a biological water processor (BWP) has been integrated with a forward osmosis secondary treatment system (FOST). Bacteria mineralize organic carbon to carbon dioxide as well as ammonia-nitrogen present in the wastewater to nitrogen gas, through a combination of nitrification and denitrification. The effluent from the BWP system is low in organic contaminants, but high in total dissolved solids. The FOST system, integrated downstream of the BWP, removes dissolved solids through a combination of concentration-driven forward osmosis and pressure driven reverse osmosis. The integrated system testing planned for this year is expected to produce water that requires only a polishing step to meet potable water requirements for spaceflight. The pilot study in California is being conducted on Golden State Water Company's Yukon wells that have hydrogen sulfide odor

  10. From Earth to Space: Application of Biological Treatment for the Removal of Ammonia from Water

    NASA Technical Reports Server (NTRS)

    Ghosh, Amlan; Seidel, Chad; Adam, Niklas; Pickering, Karen; White, Dawn

    2014-01-01

    Managing ammonia is often a challenge in both drinking water and wastewater treatment facilities. Ammonia is unregulated in drinking water, but its presence may result in numerous water quality issues in the distribution system such as loss of residual disinfectant, nitrification, and corrosion. Ammonia concentrations need to be managed in wastewater effluent to sustain the health of receiving water bodies. Biological treatment involves the microbiological oxidation of ammonia to nitrate through a two-step process. While nitrification is common in the environment, and nitrifying bacteria can grow rapidly on filtration media, appropriate conditions, such as the presence of dissolved oxygen and required nutrients, need to be established. This presentation will highlight results from two ongoing research programs - one at NASA's Johnson Space Center, and the other at a drinking water facility in California. Both programs are designed to demonstrate nitrification through biological treatment. The objective of NASA's research is to be able to recycle wastewater to potable water for spaceflight mission. To this end, a biological water processor (BWP) has been integrated with a forward osmosis secondary treatment system (FOST). Bacteria mineralize organic carbon to carbon dioxide as well as ammonia-nitrogen present in the wastewater to nitrogen gas, through a combination of nitrification and denitrification. The effluent from the BWP system is low in organic contaminants, but high in total dissolved solids. The FOST system, integrated downstream of the BWP, removes dissolved solids through a combination of concentration-driven forward osmosis and pressure driven reverse osmosis. The integrated system testing planned for this year is expected to produce water that requires only a polishing step to meet potable water requirements for spaceflight. The pilot study in California is being conducted on Golden State Water Company's Yukon wellsthat have hydrogen sulfide odor

  11. Factors affecting population of filamentous bacteria in wastewater treatment plants with nutrients removal.

    PubMed

    Miłobędzka, Aleksandra; Witeska, Anna; Muszyński, Adam

    2016-01-01

    Filamentous population in activated sludge and key operational parameters of full-scale municipal wastewater treatment plants (WWTPs) with bulking problems representative for Poland were investigated with quantitative fluorescence in situ hybridization. Statistical analyses revealed few relationships between operational parameters and biovolume of filamentous bacteria. Sludge age was not only positively correlated with abundance of Chloroflexi (parametric correlation and principal component analysis (PCA)), but also differentiated Microthrix population (analysis of variance (ANOVA)). Phylum Chloroflexi and pH presented a negative relation during the study (PCA). ANOVA showed that pH of influent and sludge volume index (SVI) differentiated abundance of types 0803 and 1851 of Chloroflexi and candidate division TM7. SVI increased along with higher abundance of Microthrix (positive parametric and non-parametric correlations and positive relation in PCA). Biovolumes of morphotypes 0803 and 1851 of Chloroflexi were differentiated by organic matter in influent, also by nutrients in the case of Chloroflexi type 1851. Chemical and biological oxygen demands (COD and BOD5, respectively) were negatively correlated with Microthrix. COD also differentiated the abundance of Haliscomenobacter hydrossis. Results of the study can be used to prevent WWTPs from excessive proliferation of filamentous bacteria and operational problems caused by them--bulking and foaming of activated sludge.

  12. Removal of Pesticides and Inorganic Contaminants in Anaerobic and Aerobic Biological Contactors

    EPA Science Inventory

    This presentation contains data on the removal of pesticides (acetochlor, clethodim, dicrotophos), ammonia, nitrate, bromate and perchlorate through aerobic and anaerobic biological treatment processes.

  13. Removal of chemical oxygen demand and dissolved nutrients by a sunken lawn infiltration system during intermittent storm events.

    PubMed

    Hou, Lizhu; Yang, Huan; Li, Ming

    2014-01-01

    Urban surface water runoff typically contains high but varying amounts of organic matter and nutrients that require removal before reuse. Infiltration systems such as sunken lawns can improve water quality. However, there is currently insufficient information describing the treatment efficiency of lawn-based infiltration systems. In this study, novel sunken lawn infiltration systems (SLISs) were designed and their pollutant removal effectiveness was assessed. The results revealed that SLISs with Poa pratensis and Lolium perenne effectively removed most chemical oxygen demand (CODCr) and dissolved nutrients. Average CODCr, total nitrogen (TN), ammonium-nitrogen (NH4(+)-N) and total phosphorus (TP) concentrations were reduced by 78.93, 66.64, 71.86 and 75.83%, respectively, and the corresponding effluent concentrations met the standard for urban miscellaneous water consumption in China. The NH4(+)-N in the synthetic runoff was shown to be removed by adsorption during the stormwater dosing and nitrification during subsequent dry days, as well as through uptake by plants. Phosphorus was mainly removed by adsorption and chemical precipitation. The NH4(+)-N and phosphorus Langmuir isotherm model fitted the clay loam soil adsorption process better than the Freundlich model. Overall, these results indicate that an SLIS provides an alternative means of removing runoff pollutants owing to its efficiency, easy operation and maintenance.

  14. Nutrient removal and biomass production in an outdoor pilot-scale phototrophic biofilm reactor for effluent polishing.

    PubMed

    Boelee, N C; Janssen, M; Temmink, H; Shrestha, R; Buisman, C J N; Wijffels, R H

    2014-01-01

    An innovative pilot-scale phototrophic biofilm reactor was evaluated over a 5-month period to determine its capacity to remove nitrogen and phosphorus from Dutch municipal wastewater effluents. The areal biomass production rate ranged between 2.7 and 4.5 g dry weight/m(2)/day. The areal nitrogen and phosphorus removal rates averaged 0.13 g N/m(2)/day and 0.023 g P/m(2)/day, which are low compared to removal rates achieved in laboratory biofilm reactors. Nutrient removal increased during the day, decreased with decreasing light intensity and no removal occurred during the night. Additional carbon dioxide supply was not requisite as the wastewater was comprised of enough inorganic carbon to sustain microalgal growth. The study was not conclusive for the limiting factor that caused the low nutrient removal rate, possibly the process was limited by light and temperature, in combination with pH increases above pH 9 during the daytime. This pilot-scale study demonstrated that the proposed phototrophic biofilm reactor is not a viable post-treatment of municipal wastewater effluents under Dutch climate conditions. However, the reactor performance may be improved when controlling the pH and the temperatures in the morning. With these adaptations, a phototrophic biofilm reactor could be feasible at lower latitudes with higher irradiance levels.

  15. High nutrient pulses, tidal mixing and biological response in a small California estuary: Variability in nutrient concentrations from decadal to hourly time scales

    USGS Publications Warehouse

    Caffrey, J.M.; Chapin, T.P.; Jannasch, H.W.; Haskins, J.C.

    2007-01-01

    Elkhorn Slough is a small estuary in Central California, where nutrient inputs are dominated by runoff from agricultural row crops, a golf course, and residential development. We examined the variability in nutrient concentrations from decadal to hourly time scales in Elkhorn Slough to compare forcing by physical and biological factors. Hourly data were collected using in situ nitrate analyzers and water quality data sondes, and two decades of monthly monitoring data were analyzed. Nutrient concentrations increased from the mid 1970s to 1990s as pastures and woodlands were converted to row crops and population increased in the watershed. Climatic variability was also a significant factor controlling interannual nutrient variability, with higher nutrient concentrations during wet than drought years. Elkhorn Slough has a Mediterranean climate with dry and rainy seasons. Dissolved inorganic nitrogen (DIN) concentrations were relatively low (10-70 ??mol L-1) during the dry season and high (20-160 ??mol L-1) during the rainy season. Dissolved inorganic phosphorus (DIP) concentrations showed the inverse pattern, with higher concentrations during the dry season. Pulsed runoff events were a consistent feature controlling nitrate concentrations during the rainy season. Peak nitrate concentrations lagged runoff events by 1 to 6 days. Tidal exchange with Monterey Bay was also an important process controlling nutrient concentrations, particularly near the mouth of the Slough. Biological processes had the greatest effect on nitrate concentrations during the dry season and were less important during the rainy season. While primary production was enhanced by nutrient pulses, chlorophyll a concentrations were not. We believe that the generally weak biological response compared to the strong physical forcing in Elkhorn Slough occurred because the short residence time and tidal mixing rapidly diluted nutrient pulses. ?? 2006 Elsevier Ltd. All rights reserved.

  16. SPREX (Spring Removal Experiment): Hydrographic data report: Volume 3, Chlorophyll and nutrients, April 1985

    SciTech Connect

    Chandler, W.S.; Bush, K.A.; Kim, C.; Berger, T.J.; Atkinson, L.P.

    1987-12-01

    SPREX (Spring Removal Experiment) took place to determine the processes affecting the transport and fate of freshwater input to the continental shelf off Georgia and South Carolina during the time of expected high runoff. It was hypothesized that this water is transported offshore in spring by a semi-permanent cyclonic eddy located at about 32/sup 0/N, 79/sup 0/W. The SPREX field program included a large array of moored current meters and other instruments, and three research vessels (R/V Cape Floria, R/V Cape Hatteras, and R/V Blue Fin) that conducted hydrographic mapping and biological and chemical sampling. The R/V Blue Fin conducted a series of seven one-day cruises covering a small region of the inner continental shelf near the Savannah River, which is the major freshwater source to the area. Ship surveys were designed to provide near synoptic coverage of a few specific events during SPREX. The purpose of the surveys was to determine the time variations in fresh water content and tracer concentrations over the shelf, the characteristics of shelf water/Gulf Stream water interaction, and biological responses to the events. 4 refs., 3 figs., 1 tab.

  17. Carbon dioxide capture and nutrients removal utilizing treated sewage by concentrated microalgae cultivation in a membrane photobioreactor.

    PubMed

    Honda, Ryo; Boonnorat, Jarungwit; Chiemchaisri, Chart; Chiemchaisri, Wilai; Yamamoto, Kazuo

    2012-12-01

    A highly efficient microalgae cultivation process was developed for carbon dioxide capture using nutrients from treated sewage. A submerged-membrane filtration system was installed in a photobioreactor to achieve high nutrient loading and to maintain a high concentration and production of microalgae. Chlorella vulgaris, Botryococcus braunii and Spirulina platensis were continuously cultivated with simulated treated sewage and 1%-CO(2) gas. The optimum hydraulic retention time (HRT) and solids retention time (SRT) were explored to achieve the maximum CO(2) capture rate, nutrient removal rate and microalgae biomass productivity. The carbon dioxide capture rate and volumetric microalgae productivity were high when the reactor was operated under 1-day (HRT) and 18-days (SRT) conditions. The independent control of HRT and SRT is effective for efficient microalgae cultivation and carbon dioxide capture using treated sewage.

  18. Biomass Production and Nutrient Removal by Switchgrass (Panicum virgatum) under Irrigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Perennial herbaceous bioenergy crops have the potential to improve soil quality, sequester soil C, enhance nutrient cycling improve wildlife habitat, and supply a portion of U.S. energy needs when used as a fuel. Assessments of the export of essential plant nutrients are needed to determine impacts ...

  19. Biologically-based signal processing system applied to noise removal for signal extraction

    DOEpatents

    Fu, Chi Yung; Petrich, Loren I.

    2004-07-13

    The method and system described herein use a biologically-based signal processing system for noise removal for signal extraction. A wavelet transform may be used in conjunction with a neural network to imitate a biological system. The neural network may be trained using ideal data derived from physical principles or noiseless signals to determine to remove noise from the signal.

  20. 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

  1. Microbiological study of bacteriophage induction in the presence of chemical stress factors in enhanced biological phosphorus removal (EBPR).

    PubMed

    Motlagh, Amir Mohaghegh; Bhattacharjee, Ananda S; Goel, Ramesh

    2015-09-15

    Polyphosphate accumulating organisms (PAOs) are responsible for carrying the enhanced biological phosphorus removal (EBPR). Although the EBPR process is well studied, the failure of EBPR performance at both laboratory and full-scale plants has revealed a lack of knowledge about the ecological and microbiological aspects of EBPR processes. Bacteriophages are viruses that infect bacteria as their sole host. Bacteriophage infection of polyphosphate accumulating organisms (PAOs) has not been considered as a main contributor to biological phosphorus removal upsets. This study examined the effects of different stress factors on the dynamics of bacteriophages and the corresponding effects on the phosphorus removal performance in a lab-scale EBPR system. The results showed that copper (heavy metal), cyanide (toxic chemical), and ciprofloxacin (antibiotic), as three different anthropogenic stress factors, can induce phages integrated onto bacterial genomes (i.e. prophages) in an enriched EBPR sequencing batch reactor, resulting in a decrease in the polyphosphate kinase gene ppk1 clades copy number, phosphorus accumulation capacity, and phosphorus removal performance. This study opens opportunities for further research on the effects of bacteriophages in nutrient cycles both in controlled systems such as wastewater treatment plants and natural ecosystems.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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.

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

    PubMed

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

    2015-02-27

    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.

  4. Inhibition of chemical dose in biological phosphorus and nitrogen removal in simultaneous chemical precipitation for phosphorus removal.

    PubMed

    Liu, Yanchen; Shi, Hanchang; Li, Wenlin; Hou, Yanling; He, Miao

    2011-03-01

    A study on the influence of chemical dosing on biological phosphorus and nitrogen removal was carried out through batch experimental tests by lab-scale and a full-scale wastewater treatment plant (employing a typical anaerobic-anoxic-oxic treatment). Results indicated that the inhibition of aluminum salt on biological phosphorus release and uptake processes is significant, as well as the inhibition of aluminum salt on Ammonia-Oxidizing Bacteria (AOB) is dominantly observed in the nitrification process and is recoverability. The inhibition of iron salt in biological phosphorus and nitrogen removal is weak, and only the inhibition of iron salt on phosphorus release at anaerobic periods emerge under large dosing. Evidence shows persistent inhibition from the accumulation of chemical doses in sludge mass. Intermittent chemical dosing proves recommendable for simultaneous chemical phosphorus removal.

  5. Nutrient removal of agricultural drainage water using algal turf scrubbers and solar power

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  6. Scrubbing the Bay: Nutrient Removal Using Small Algal Turf Scrubbers on Chesapeake Bay Tributaries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  7. 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.

  8. Improvement of DOC removal by multi-stage AOP-biological treatment.

    PubMed

    Fahmi; Nishijima, Wataru; Okada, Mitsumasa

    2003-03-01

    The single and multi-stages advanced oxidation process (AOP)-biological treatments were evaluated to apply for drinking water treatment, especially for the water containing less susceptible dissolved organic carbon (DOC) to ozone, comparing with the ozonation-biological treatment. Minaga reservoir water and the secondary effluent from a Municipal wastewater treatment plant were used as dissolved organic matter (DOM) solutions. DOC removals after 60 min AOP-biological treatment were 62% and 41% in the Minaga reservoir water and the secondary effluent, respectively, whereas those in the ozonation-biological treatment only 40% and 15% of DOC were removed, respectively. The result indicated that the single-stage AOP-biological treatment could improve DOC removal in comparison with the single-stage ozonation-biological treatment. This is because the AOP mineralized both biodegradable dissolved organic carbon (BDOC) produced in the early stage of oxidation and non-biodegradable dissolved organic carbon (NBDOC), whereas only BDOC was mineralized by further ozonation and NBDOC was not oxidized in the ozonation-biological treatment. The multi-stage treatment could not improve DOC removal in comparison with the single-stage treatment in the ozonation-biological treatment for the secondary effluent containing less susceptible DOC to ozone. However, the multi-stage AOP-biological treatment significantly reduced DOC and achieved 71% of DOC removal by 4 times repetition of 15 min oxidation, whereas DOC removal was 41% in the single-stage AOP-biological treatment for the same oxidation time. The improvement of DOC removal by the multi-stage AOP-biological treatment was due to BDOC removal as a radical scavenger by subsequent biological treatment in the early stage of oxidation and direct mineralization in the latter stage of oxidation.

  9. Removal of nutrients and organic pollution load from pulp and paper mill effluent by microalgae in outdoor open pond.

    PubMed

    Usha, M T; Sarat Chandra, T; Sarada, R; Chauhan, V S

    2016-08-01

    A mixed culture of microalgae, containing two Scenedesmus species, was analysed to determine its potential in coupling of pulp and paper mill effluent treatment and microalgal cultivation. Laboratory studies suggested that 60% concentration of wastewater was optimum for microalgal cultivation. A maximum of 82% and 75% removal of BOD and COD respectively was achieved with microalgal cultivation in outdoor open pond. By the end of the cultivation period, 65% removal of NO3-N and 71.29% removal of PO4-P was observed. The fatty acid composition of mixed microalgal culture cultivated with effluent showed the palmitic acid, oleic acid, linoleic acid and α-linolenic acid as major fatty acids. The results obtained suggest that pulp and paper mill effluent could be used effectively for cultivation of microalgae to minimise the freshwater and nutrient requirements.

  10. Effect of subalpine canopy removal on snowpack, soil solution, and nutrient export, Fraser Experimental Forest, CO

    USGS Publications Warehouse

    Stottlemyer, R.; Troendle, C.A.

    1999-01-01

    proportionally greater than water flux. Increased subsurface flow accounted for most of the increase in non-limiting nutrient loss. For limiting nutrients, loss of plant uptake and increased shallow subsurface flow accounted for the greater loss. Seasonal ion concentration patterns in streamwater and subsurface flow were similar.Research on the effects of vegetation manipulation on snowpack, soil water, and streamwater chemistry and flux has been underway at the Fraser Experimental Forest (FEF), CO, since 1982. Greater than 95% of FEF snowmelt passes through watersheds as subsurface flow where soil processes significantly alter meltwater chemistry. To better understand the mechanisms accounting for annual variation in watershed streamwater ion concentration and flux with snowmelt, we studied subsurface water flow, its ion concentration, and flux in conterminous forested and clear cut plots. Repetitive patterns in subsurface flow and chemistry were apparent. Control plot subsurface flow chemistry had the highest ion concentrations in late winter and fall. When shallow subsurface flow occurred, its Ca2+, SO42-, and HCO3- concentrations were lower and K+ higher than deep flow. The percentage of Ca2+, NO3-, SO42-, and HCO3- flux in shallow depths was less and K+ slightly greater than the percentage of total flow. Canopy removal increased precipitation reaching the forest floor by about 40%, increased peak snowpack water equivalent (SWE) > 35%, increased the average snowpack Ca2+, NO3-, and NH4+ content, reduced the snowpack K+ content, and increased the runoff four-fold. Clear cutting doubled the percentage of subsurface flow at shallow depths, and increased K+ concentration in shallow subsurface flow and NO3- concentrations in both shallow and deep flow. The percentage change in total Ca2+, SO42-, and HCO3- flux in shallow depths was less than the change in water flux, while that of K+ and NO3- flux was greater. Relative to the control, in the clear cut the percentage of total Ca

  11. Long-term study on the impact of temperature on enhanced biological phosphorus and nitrogen removal in membrane bioreactor.

    PubMed

    Sayi-Ucar, N; Sarioglu, M; Insel, G; Cokgor, E U; Orhon, D; van Loosdrecht, M C M

    2015-11-01

    The study involved experimental observation and performance evaluation of a membrane bioreactor system treating municipal wastewater for nutrient removal for a period 500 days, emphasizing the impact of high temperature on enhanced biological phosphorus removal (EBPR). The MBR system was operated at relatively high temperatures (24-41 °C). During the operational period, the total phosphorus (TP) removal gradually increased from 50% up to 95% while the temperature descended from 41 to 24 °C. At high temperatures, anaerobic volatile fatty acid (VFA) uptake occurred with low phosphorus release implying the competition of glycogen accumulating organisms (GAOs) with polyphosphate accumulating organisms (PAOs). Low dissolved oxygen conditions associated with high wastewater temperatures did not appreciable affected nitrification but enhanced nitrogen removal. Dissolved oxygen levels around 1.0 mgO2/L in membrane tank provided additional denitrification capacity of 6-7 mgN/L by activating simultaneous nitrification and denitrification. As a result, nearly complete removal of nitrogen could be achieved in the MBR system, generating a permeate with no appreciable nitrogen content. The gross membrane flux was 43 LMH corresponding to the specific permeability (K) of 413 LMH/bar at 39 °C in the MBR tank. The specific permeability increased by the factor of 43% at 39 °C compared to that of 25 °C during long-term operation.

  12. High and stable substrate specificities of microorganisms in enhanced biological phosphorus removal plants.

    PubMed

    Kindaichi, Tomonori; Nierychlo, Marta; Kragelund, Caroline; Nielsen, Jeppe Lund; Nielsen, Per Halkjaer

    2013-06-01

    Microbial communities are typically characterized by conditions of nutrient limitation so the availability of the resources is likely a key factor in the niche differentiation across all species and in the regulation of the community structure. In this study we have investigated whether four species exhibit any in situ short-term changes in substrate uptake pattern when exposed to variations in substrate and growth conditions. Microautoradiography was combined with fluorescence in situ hybridization to investigate in situ cell-specific substrate uptake profiles of four probe-defined coexisting species in a wastewater treatment plant with enhanced biological phosphorus removal. These were the filamentous 'Candidatus Microthrix' and Caldilinea (type 0803), the polyphosphate-accumulating organism 'Candidatus Accumulibacter', and the denitrifying Azoarcus. The experimental conditions mimicked the conditions potentially encountered in the respective environment (starvation, high/low substrate concentration, induction with specific substrates, and single/multiple substrates). The results showed that each probe-defined species exhibited very distinct and constant substrate uptake profile in time and space, which hardly changed under any of the conditions tested. Such niche partitioning implies that a significant change in substrate composition will be reflected in a changed community structure rather than the substrate uptake response from the different species.

  13. Enhanced mixotrophic growth of microalga Chlorella sp. on pretreated swine manure for simultaneous biofuel feedstock production and nutrient removal.

    PubMed

    Hu, Bing; Min, Min; Zhou, Wenguang; Du, Zhenyi; Mohr, Michael; Chen, Paul; Zhu, Jun; Cheng, Yanling; Liu, Yuhuan; Ruan, Roger

    2012-12-01

    The objectives were to assess the feasibility of using fermented liquid swine manure (LSM) as nutrient supplement for cultivation of Chlorella sp. UMN271, a locally isolated facultative heterotrophic strain, and to evaluate the nutrient removal efficiencies by alga compared with those from the conventionally decomposed LSM-algae system. The results showed that addition of 0.1% (v/v) acetic, propionic and butyric acids, respectively, could promote algal growth, enhance nutrient removal efficiencies and improve total lipids productivities during a 7-day batch cultivation. Similar results were observed when the acidogenic fermentation was applied to the sterilized and raw digested LSM rich in volatile fatty acids (VFAs). High algal growth rate (0.90 d(-1)) and fatty acid content (10.93% of the dry weight) were observed for the raw VFA-enriched manure sample. Finally, the fatty acid profile analyses showed that Chlorella sp. grown on acidogenically digested manure could be used as a feedstock for high-quality biodiesel production.

  14. Effect of mine wastewater on nutrient removal and lipid production by a green microalga Micratinium reisseri from concentrated municipal wastewater.

    PubMed

    Ji, Min-Kyu; Kabra, Akhil N; Salama, El-Sayed; Roh, Hyun-Seog; Kim, Jung Rae; Lee, Dae Sung; Jeon, Byong-Hun

    2014-04-01

    Effect of mine wastewater on the nutrient removal efficiency of a green microalga Micratinium reisseri from concentrated municipal wastewater (CMW) with simultaneous lipid production was investigated. Different dilution ratios (1-10%) of CMW either with mine wastewater (MWF) or mine wastewater without Fe (MWOF) were used. M. reisseri showed the highest growth (0.8gL(-1)) and nutrient uptake (35.9mgTNL(-1) and 5.4mgTPL(-1)) at 3% MWF ([Fe]tot=6.7mgL(-1)), and the highest lipid productivity (10.4mgL(-1)day(-1)) at 5% MWF ([Fe]tot=11.2mgL(-1)) after 15days. CMW supported the algal autoflocculation due to formation of phosphate, calcium and magnesium precipitates at a high suspension pH. Fatty acid methyl ester analysis revealed that the microalgal lipids possessed 79-82% of C16/C18 fatty acids. Application of mine wastewater improved the nutrient removal efficiency, growth and lipid productivity of M. reisseri cultivated in CMW.

  15. Nutrient Regulation by Continuous Feeding Removes Limitations on Cell Yield in the Large-Scale Expansion of Mammalian Cell Spheroids

    PubMed Central

    Weegman, Bradley P.; Nash, Peter; Carlson, Alexandra L.; Voltzke, Kristin J.; Geng, Zhaohui; Jahani, Marjan; Becker, Benjamin B.; Papas, Klearchos K.; Firpo, Meri T.

    2013-01-01

    Cellular therapies are emerging as a standard approach for the treatment of several diseases. However, realizing the promise of cellular therapies across the full range of treatable disorders will require large-scale, controlled, reproducible culture methods. Bioreactor systems offer the scale-up and monitoring needed, but standard stirred bioreactor cultures do not allow for the real-time regulation of key nutrients in the medium. In this study, β-TC6 insulinoma cells were aggregated and cultured for 3 weeks as a model of manufacturing a mammalian cell product. Cell expansion rates and medium nutrient levels were compared in static, stirred suspension bioreactors (SSB), and continuously fed (CF) SSB. While SSB cultures facilitated increased culture volumes, no increase in cell yields were observed, partly due to limitations in key nutrients, which were consumed by the cultures between feedings, such as glucose. Even when glucose levels were increased to prevent depletion between feedings, dramatic fluctuations in glucose levels were observed. Continuous feeding eliminated fluctuations and improved cell expansion when compared with both static and SSB culture methods. Further improvements in growth rates were observed after adjusting the feed rate based on calculated nutrient depletion, which maintained physiological glucose levels for the duration of the expansion. Adjusting the feed rate in a continuous medium replacement system can maintain the consistent nutrient levels required for the large-scale application of many cell products. Continuously fed bioreactor systems combined with nutrient regulation can be used to improve the yield and reproducibility of mammalian cells for biological products and cellular therapies and will facilitate the translation of cell culture from the research lab to clinical applications. PMID:24204645

  16. Achieving the nitrite pathway using aeration phase length control and step-feed in an SBR removing nutrients from abattoir wastewater.

    PubMed

    Lemaire, Romain; Marcelino, Marcos; Yuan, Zhiguo

    2008-08-15

    Aeration phase length control and step-feed of wastewater are used to achieve nitrogen removal from wastewater via nitrite in sequencing batch reactors (SBR). Aeration is switched off as soon as ammonia oxidation is completed, which is followed by the addition of a fraction of the wastewater that the SBR receives over a cycle to facilitate denitrification. The end-point of ammonia oxidation is detected from the on-line measured pH and oxygen uptake rate (OUR). The method was implemented in an SBR achieving biological nitrogen and phosphorus removal from anaerobically pre-treated abattoir wastewater. The degree of nitrite accumulation during the aeration period was monitored along with the variation in the nitrite oxidizing bacteria (NOB) population using fluorescence in situ hybridization (FISH) techniques. It is demonstrated that the nitrite pathway could be repeatedly and reliably achieved, which significantly reduced the carbon requirement for nutrient removal. Model-based studies show that the establishment of the nitrite pathway was primarily the result of a gradual reduction of the amount of nitrite that is available to provide energy for the growth of NOB, eventually leading to the elimination of NOB from the system.

  17. EBP2R - an innovative enhanced biological nutrient recovery activated sludge system to produce growth medium for green microalgae cultivation.

    PubMed

    Valverde-Pérez, Borja; Ramin, Elham; Smets, Barth F; Plósz, Benedek Gy

    2015-01-01

    Current research considers wastewater as a source of energy, nutrients and water and not just a source of pollution. So far, mainly energy intensive physical and chemical unit processes have been developed to recover some of these resources, and less energy and resource demanding alternatives are needed. Here, we present a modified enhanced biological phosphorus removal and recovery system (referred to as EBP2R) that can produce optimal culture media for downstream micro-algal growth in terms of N and P content. Phosphorus is recovered as a P-stream by diversion of some of the effluent from the upstream anaerobic reactor. By operating the process at comparably low solids retention times (SRT), the nitrogen content of wastewater is retained as free and saline ammonia, the preferred form of nitrogen for most micro-algae. Scenario simulations were carried out to assess the capacity of the EBP2R system to produce nutrient rich organic-carbon depleted algal cultivation media of target composition. Via SRT control, the quality of the constructed cultivation media can be optimized to support a wide range of green micro-algal growth requirements. Up to 75% of the influent phosphorus can be recovered, by diverting 30% of the influent flow as a P-stream at an SRT of 5 days. Through global sensitivity analysis we find that the effluent N-to-P ratio and the P recovered are mainly dependent on the influent quality rather than on biokinetics or stoichiometry. Further research is needed to demonstrate that the system performance predicted through the model-based design can be achieved in reality.

  18. Soil fertility in deserts: a review on the influence of biological soil crusts and the effect of soil surface disturbance on nutrient inputs and losses

    USGS Publications Warehouse

    Reynolds, R.; Phillips, S.; Duniway, M.; Belnap, J.

    2003-01-01

    Sources of desert soil fertility include parent material weathering, aeolian deposition, and on-site C and N biotic fixation. While parent materials provide many soil nutrients, aeolian deposition can provide up to 75% of plant-essential nutrients including N, P, K, Mg, Na, Mn, Cu, and Fe. Soil surface biota are often sticky, and help retain wind-deposited nutrients, as well as providing much of the N inputs. Carbon inputs are from both plants and soil surface biota. Most desert soils are protected by cyanobacterial-lichen-moss soil crusts, chemical crusts and/or desert pavement. Experimental disturbances applied in US deserts show disruption of soil surfaces result in decreased N and C inputs from soil biota by up to 100%. The ability to glue aeolian deposits in place is compromised, and underlying soils are exposed to erosion. The ability to withstand wind increases with biological and physical soil crust development. While most undisturbed sites show little sediment production, disturbance by vehicles or livestock produce up to 36 times more sediment production, with soil movement initiated at wind velocities well below commonly-occurring wind speeds. Soil fines and flora are often concentrated in the top 3 mm of the soil surface. Winds across disturbed areas can quickly remove this material from the soil surface, thereby potentially removing much of current and future soil fertility. Thus, disturbances of desert soil surfaces can both reduce fertility inputs and accelerate fertility losses.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. Effect of gradual-increasing aeration mode in an aerobic tank on nutrients' removal and functional microbial communities.

    PubMed

    Zhao, Yang-Guo; Guo, Xiaoma; She, Zonglian; Gao, Mengchun; Guo, Liang

    2016-12-30

    Different aeration rates and modes in an aerobic tank of an anaerobic/anoxic/aerobic (A(2)O) process were investigated to reveal their influence on nitrogen and phosphorus removal efficiency. Meanwhile, Illumina high-throughput sequencing of partial 16S rRNA gene of bacteria was conducted to monitor the abundance and composition of microbial communities. The results showed that higher aeration rate led to better nutrients' removal efficiency. The gradual-increasing aeration mode along the wastewater stream enhanced the contaminants' removal and the system achieved chemical oxygen demand, [Formula: see text]-N, total nitrogen (TN) removal rates of 72%, 96% and 51%, respectively. However, the gradual-decreasing or uniform aeration modes resulted in inefficient removal of TN, especially the ammonia due to low DO in the end parts of A(2)O. Microbial community analysis indicated that denitrifying phosphorus-accumulating bacteria Acinetobacter spp. were the most dominant groups under the gradual-increasing aeration mode in all tanks of the A(2)O bioreactor. Moreover, the members of genera Clostridium, Thauera and Dechloromonas also largely existed in the system. The gradual-increasing aeration mode and cooperation of different groups of bacteria made the system stable and high-performance.

  1. 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

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

    PubMed

    Scholz, Fabian G; Bucci, Sandra J; Goldstein, Guillermo; Meinzer, Frederick C; Franco, Augusto C; Miralles-Wilhelm, Fernando

    2007-04-01

    Under certain environmental conditions, nocturnal transpiration can be relatively high in temperate and tropical woody species. We have previously shown that nocturnal sap flow accounts for up to 28% of total daily transpiration in woody species growing in a nutrient-poor Brazilian Cerrado ecosystem. In the present study, we assessed the effect of increased nutrient supply on nocturnal transpiration in three dominant Cerrado tree species to explore the hypothesis that, in nutrient-poor systems, continued transpiration at night may enhance delivery of nutrients to root-absorbing surfaces. We compared nocturnal transpiration of trees growing in unfertilized plots and plots to which nitrogen (N) and phosphorus (P) had been added twice yearly from 1998 to 2005. Three independent indicators of nocturnal transpiration were evaluated: sap flow in terminal branches, stomatal conductance (g(s)), and disequilibrium in water potential between covered and exposed leaves (DeltaPsi(L)). In the unfertilized trees, about 25% of the total daily sap flow occurred at night. Nocturnal sap flow was consistently lower in the N- and P-fertilized trees, significantly so in trees in the N treatment. Similarly, nocturnal g(s) was consistently lower in fertilized trees than in unfertilized trees where it sometimes reached values of 150 mmol m(-2) s(-1) by the end of the dark period. Predawn gs and the percentage of nocturnal sap flow were linearly related. Nocturnal DeltaPsi(L) was significantly greater in the unfertilized trees than in N- and P-fertilized trees. The absolute magnitude of DeltaPsi(L) increased linearly with the percentage of nocturnal sap flow. These results are consistent with the idea that enhancing nutrient uptake by allowing additional transpiration to occur at night when evaporative demand is lower may avoid excessive dehydration associated with increased stomatal opening during the day when evaporative demand is high.

  3. Impact of nitrite on aerobic phosphorus uptake by poly-phosphate accumulating organisms in enhanced biological phosphorus removal sludges.

    PubMed

    Zeng, Wei; Li, Boxiao; Yang, Yingying; Wang, Xiangdong; Li, Lei; Peng, Yongzhen

    2014-02-01

    Impact of nitrite on aerobic phosphorus (P) uptake of poly-phosphate accumulating organisms (PAOs) in three different enhanced biological phosphorus removal (EBPR) systems was investigated, i.e., the enriched PAOs culture fed with synthetic wastewater, the two lab-scale sequencing batch reactors (SBRs) treating domestic wastewater for nutrient removal through nitrite-pathway nitritation and nitrate-pathway nitrification, respectively. Fluorescence in situ hybridization results showed that PAOs in the three sludges accounted for 72, 7.6 and 6.5% of bacteria, respectively. In the enriched PAOs culture, at free nitrous acid (FNA) concentration of 0.47 × 10(-3) mg HNO₂-N/L, aerobic P-uptake and oxidation of intercellular poly-β-hydroxyalkanoates were both inhibited. Denitrifying phosphorus removal under the aerobic conditions was observed, indicating the existence of PAOs using nitrite as electron acceptor in this culture. When the FNA concentration reached 2.25 × 10(-3) mg HNO2-N/L, denitrifying phosphorus removal was also inhibited. And the inhibition ceased once nitrite was exhausted. Corresponding to both SBRs treating domestic wastewater with nitritation and nitrification pathway, nitrite inhibition on aerobic P-uptake by PAOs did not occur even though FNA concentration reached 3 × 10(-3) and 2.13 × 10(-3) mg HNO₂-N/L, respectively. Therefore, PAOs taken from different EBPR activated sludges had different tolerance to nitrite.

  4. Nutrient removal and energy production from aqueous phase of bio-oil generated via hydrothermal liquefaction of algae.

    PubMed

    Shanmugam, Saravanan R; Adhikari, Sushil; Shakya, Rajdeep

    2017-04-01

    Removal of nutrients (phosphorus and nitrogen) as struvite from bio-oil aqueous phase generated via hydrothermal liquefaction of algae was evaluated in this study. Effect of process parameters such as pH, temperature and reaction time on struvite formation was studied. More than 99% of phosphorus and 40-100% ammonium nitrogen were removed under all experimental conditions. X-ray diffraction analysis confirmed the formation of struvite, and the struvite recovered from bio-oil aqueous phase can be used as a slow-release fertilizer. Biogas production from struvite recovered bio-oil aqueous phase showed 3.5 times higher CH4 yield (182±39mL/g COD) as compared to non-struvite recovered aqueous phase. The results from this study indicate that both struvite and methane can be produced from bio-oil aqueous phase.

  5. Environmental distribution and population biology of Candidatus Accumulibacter, a primary agent of Biological Phosphorus Removal

    PubMed Central

    Peterson, S. Brook; Warnecke, Falk; Madejska, Julita; McMahon, Katherine D.; Hugenholtz, Philip

    2008-01-01

    Summary Members of the uncultured bacterial genus Candidatus Accumulibacter are capable of intracellular accumulation of inorganic phosphate (Pi) in activated sludge wastewater treatment plants (WWTPs) performing enhanced biological phosphorus removal (EBPR), but were also recently shown to inhabit freshwater and estuarine sediments. Additionally, metagenomic sequencing of two bioreactor cultures enriched in Candidatus Accumulibacter, but housed on separate continents, revealed the potential for global dispersal of particular Candidatus Accumulibacter strains, that we hypothesize is facilitated by the ability of Candidatus Accumulibacter to persist in environmental habitats. In the current study, we used sequencing of a phylogenetic marker, the ppk1 gene, to characterize Candidatus Accumulibacter populations in diverse environments, at varying distances from WWTPs. We discovered several new lineages of Candidatus Accumulibacter which had not previously been detected in WWTPs, and also uncovered new diversity and structure within previously detected lineages. Habitat characteristics were found to be a key determinant of Candidatus Accumulibacter lineage distribution, while, as predicted, geographic distance played little role in limiting dispersal on a regional scale. However, on a local scale, enrichment of particular Candidatus Accumulibacter lineages in WWTP appeared to impact local environmental populations. These results provide evidence of ecological differences among Candidatus Accumulibacter lineages. PMID:18643843

  6. 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.

  7. 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.

  8. Microalgal-biotechnology as a platform for an integral biogas upgrading and nutrient removal from anaerobic effluents.

    PubMed

    Bahr, Melanie; Díaz, Ignacio; Dominguez, Antonio; González Sánchez, Armando; Muñoz, Raul

    2014-01-01

    The potential of a pilot high rate algal pond (HRAP) interconnected via liquid recirculation with an external absorption column for the simultaneous removal of H2S and CO2 from biogas using an alkaliphilic microalgal-bacterial consortium was evaluated. A bubble column was preferred as external absorption unit to a packed bed column based on its ease of operation, despite showing a comparable CO2 mass transfer capacity. When the combined HRAP-bubble column system was operated under continuous mode with mineral salt medium at a biogas residence time of 30 min in the absorption column, the system removed 100% of the H2S (up to 5000 ppmv) and 90% of the CO2 supplied, with O2 concentrations in the upgraded biogas below 0.2%. The use of diluted centrates as a free nutrient source resulted in a gradual decrease in CO2 removal to steady values of 40%, while H2S removal remained at 100%. The anaerobic digestion of the algal-bacterial biomass produced during biogas upgrading resulted in a CH4 yield of 0.21-0.27 L/gVS, which could satisfy up to 60% of the overall energy demand for biogas upgrading. This proof of concept study confirmed that algal-bacterial photobioreactors can support an integral upgrading without biogas contamination, with a net negative CO2 footprint, energy production, and a reduction of the eutrophication potential of the residual anaerobic effluents.

  9. Growth rate, organic carbon and nutrient removal rates of Chlorella sorokiniana in autotrophic, heterotrophic and mixotrophic conditions.

    PubMed

    Kim, Sunjin; Park, Jeong-eun; Cho, Yong-Beom; Hwang, Sun-Jin

    2013-09-01

    This study sought to investigate the growth rate and organic carbon and nutrient removal efficiency of Chlorella sorokiniana under autotrophic, heterotrophic and mixotrophic conditions. Growth rates of the microalgae were 0.24 d(-1), 0.53 d(-1) and 0.44 d(-1) in autotrophic, heterotrophic and mixotrophic conditions, respectively. The growth rate of C. sorokiniana was significantly higher for that grown under heterotrophic conditions. The nitrogen removal rates were 13.1 mg-N/L/day, 23.9 mg-N/L/day and 19.4 mg-N/L/day, respectively. The phosphorus removal rates reached to 3.4 mg-P/L/day, 5.6 mg-P/L/day and 5.1 mg-P/L/day, respectively. Heterotrophic conditions were superior in terms of the microalgae growth and removal of nitrogen and phosphorus compared to autotrophic and mixotrophic conditions, suggesting that microalgae cultured under this condition would be most useful for application in wastewater treatment systems.

  10. Sand filters for removal of microbes and nutrients from wastewater during a one-year pilot study in a cold temperate climate.

    PubMed

    Kauppinen, Ari; Martikainen, Kati; Matikka, Ville; Veijalainen, Anna-Maria; Pitkänen, Tarja; Heinonen-Tanski, Helvi; Miettinen, Ilkka T

    2014-01-15

    Onsite wastewater treatment systems (OWTS) are recognised as potential threats to groundwater or other water environments subject to discharged effluents. In this study, the microbiological and nutrient removal properties of three different pilot-scale sand filters (SFs) were followed over a one-year period. Moreover, a separate phosphorus removal unit was tested for six months. For the best treatment system, the average log removals were 2.2-3.5 for pathogenic human noro- and adenoviruses and 4.3-5.2 and 4.6-5.4 for indicator viruses and bacteria, respectively. The system that effectively removed microbes was also efficient at removing nutrients. However, the poorest treatment system yielded substantially lower removals. The remarkable differences noted between the studied SFs highlights the importance of construction materials and the careful planning of the filters. Moreover, seasonal conditions appear to have a clear effect on purification efficiencies, emphasising the vulnerability of these systems especially in cold climates.

  11. The Impact of Temperature on Anaerobic Biological Perchlorate Removal and Aerobic Polishing of the Effluent - paper

    EPA Science Inventory

    This abstract describes a pilot-scale evaluation of anaerobic biological perchlorate (C1O4) removal followed by aerobic effluent polishing. The anaerobic biological contactor operated for 3.5 years. During that period, two effluent polishing evaluations, lasting 311 an...

  12. The Impact of Temperature on Anaerobic Biological Perchlorate Removal and Aerobic Polishing of the Effluent

    EPA Science Inventory

    This abstract describes a pilot-scale evaluation of anaerobic biological perchlorate (C1O4) removal followed by aerobic effluent polishing. The anaerobic biological contactor operated for 3.5 years. During that period, two effluent polishing evaluations, lasting 311 an...

  13. NITRIFICATION AND ARSENIC REMOVAL IN BIOLOGICALLY ACTIVE FILTERS: A CASE STUDY

    EPA Science Inventory

    Ammonia in source waters can cause water treatment and distribution system problems, many of which are associated with biological nitrification. Therefore, in some cases, the removal of ammonia from water is desirable. Biological oxidation of ammonia to nitrate and nitrate (nitr...

  14. NITRIFICATION AND IRON AND ARSENIC REMOVAL IN BIOLOGICALLY ACTIVE FILTERS: A CASE STUDY

    EPA Science Inventory

    Ammonia in source waters can cause water treatment and distribution system problems, many of which are associated with biological nitrification. Therefore, in some cases, the removal of ammonia from water is desirable. Biological oxidation of ammonia to nitrate and nitrate (nitr...

  15. Hybrid Adsorption-Membrane Biological Reactors for Improved Performance and Reliability of Perchlorate Removal Processes

    DTIC Science & Technology

    2008-12-01

    carbon supply for the autotrophic perchlorate reducing bacteria. The membrane used in the reactor is a hollow-fiber microfiltration membrane made from...1 HYBRID ADSORPTION- MEMBRANE BIOLOGICAL REACTORS FOR IMPROVED PERFORMANCE AND RELIABILITY OF PERCHLORATE REMOVAL PROCESSES L.C. Schideman...Center Champaign, IL 61826, USA ABSTRACT This study introduces the novel HAMBgR process (Hybrid Adsorption Membrane Biological Reactor) and

  16. Ecological Limits to Terrestrial Biological Carbon Dioxide Removal

    NASA Astrophysics Data System (ADS)

    Torn, M. S.; Smith, L. J.; Mishra, U.; Sanchez, D.; Williams, J.

    2014-12-01

    Many climate change mitigation scenarios include terrestrial atmospheric carbon dioxide removal (BCDR) or carbon neutral bioenergy production through bioenergy with carbon capture and storage (BECS) or afforestation/reforestation. Very high sequestration potentials for these strategies have been reported, and we evaluate the potential ecological limits (e.g., land and resource requirements) to implementation at the 1 Pg C y-1 scale relevant to climate change mitigation for U.S. and global scenarios. We estimate that removing 1 Pg C y-1 via tropical afforestation would require at least 7×106 ha y-1 of land, 0.09 Tg y-1 of nitrogen, and 0.2 Tg y-1 of phosphorous, and would increase evapotranspiration from those lands by almost 50%. Because of improved carbon capture technologies, we are updating (and reducing) our previous estimates for switchgrass BECS (previous estimate was 2×108 ha land and 20 Tg y-1 of nitrogen (20 % of global fertilizer nitrogen production)). Miscanthus could meet the same biomass production with much lower N demand. Moreover, transitioning the U.S land currently under corn- ethanol production to no-till perennial grasses for bioenergy would meet U.S. needs and have additional environmental benefits (such as improved wildlife habitat and soil restoration). Thus, there are both signficant ecological limits to BCDR as well as potential ecological benefits, depending on implementation.

  17. A novel membrane distillation-thermophilic bioreactor system: biological stability and trace organic compound removal.

    PubMed

    Wijekoon, Kaushalya C; Hai, Faisal I; Kang, Jinguo; Price, William E; Guo, Wenshan; Ngo, Hao H; Cath, Tzahi Y; Nghiem, Long D

    2014-05-01

    The removal of trace organic compounds (TrOCs) by a novel membrane distillation-thermophilic bioreactor (MDBR) system was examined. Salinity build-up and the thermophilic conditions to some extent adversely impacted the performance of the bioreactor, particularly the removal of total nitrogen and recalcitrant TrOCs. While most TrOCs were well removed by the thermophilic bioreactor, compounds containing electron withdrawing functional groups in their molecular structure were recalcitrant to biological treatment and their removal efficiency by the thermophilic bioreactor was low (0-53%). However, the overall performance of the novel MDBR system with respect to the removal of total organic carbon, total nitrogen, and TrOCs was high and was not significantly affected by the conditions of the bioreactor. All TrOCs investigated here were highly removed (>95%) by the MDBR system. Biodegradation, sludge adsorption, and rejection by MD contribute to the removal of TrOCs by MDBR treatment.

  18. Riparian and Associated Habitat Characteristics Related to Nutrient Concentrations and Biological Responses of Small Streams in Selected Agricultural Areas, United States, 2003-04

    USGS Publications Warehouse

    Zelt, Ronald B.; Munn, Mark D.

    2009-01-01

    sampled sites. The habitat characteristics sampled within the five study units were compared statistically. Bivariate correlations between riparian habitat variables and either nutrient-chemistry or biological-response variables were examined for all sites combined, and for sites within each study area. Nutrient concentrations were correlated with the extent of riparian cropland. For nitrogen species, these correlations were more frequently at the basin scale, whereas for phosphorus, they were about equally frequent at the segment and basin scales. Basin-level extents of riparian cropland and reach-level bank vegetative cover were correlated strongly with both total nitrogen and dissolved inorganic nitrogen (DIN) among multiple study areas, reflecting the importance of agricultural land-management and conservation practices for reducing nitrogen delivery from near-stream sources. When sites lacking segment-level wetlands were excluded, the negative correlation of riparian wetland extent with DIN among 49 sites was strong at the reach and segment levels. Riparian wetland vegetation thus may be removing dissolved nutrients from soil water and shallow groundwater passing through riparian zones. Other habitat variables that correlated strongly with nitrogen and phosphorus species included suspended sediment, light availability, and antecedent water temperature. Chlorophyll concentrations in seston were positively correlated with phosphorus concentrations for all sites combined. Benthic chlorophyll was correlated strongly with nutrient concentrations in only the Delmarva study area and only in fine-grained habitats. Current velocity or hydraulic scour could explain correlation patterns for benthic chlorophyll among Georgia sites, whereas chlorophyll in seston was correlated with antecedent water temperature among Washington and Delmarva sites. The lack of any consistent correlation pattern between habitat characteristics and organic material density (ash-free dry mass)

  19. Biomass production and nutrient removal potential of water hyacinth cultured in sewage effluent

    SciTech Connect

    Reddy, K.R.; Hueston, F.M.; McKinn, T.

    1985-05-01

    Growth and nutrient uptake of water hyacinth (Eichhornia crassipes (Mart Solms)) cultured in sewage effluent were measured over a period of one year in a prototype wastewater treatment system which has been in operation at Walt Disney World near Orlando, Florida. Annual productivity of water hyacinth cultured in primary sewage effluent (Channel II) was found to be in the range of 5 to 27 g dry wt/m/sup 2/ day (23.6 dry tons/acre yr). Average growth rate during the months of May through October 1982 for hyacinth cultured in Channel II (primary sewage effluent) and Channel I (treated primary sewage effluent leaving Channel II) was about 16 g dry wt/m/sup 2/ (27 dry tons/acre yr), compared to the growth rate of 13 g dry wt/m/sup 2/ (22 dry tons/acre yr) for hyacinths cultured in secondary sewage effluent. Plants cultured in secondary sewage effluent generally had longer roots than the plants cultured in primary sewage effluent. A significant relationship was observed between the growth rate of hyacinth and the solar radiation. N and P concentration of the plant tissue were higher in the hyacinths cultured during winter months compared to the plants grown in summer months. Average N and P concentration of the plants cultured im primary sewage effluent were found to be 3.7% N and 0.94% P, respectively, while the plants cultured in secondary sewage effluent had a total N and P content of 2.8% N and 0.79% P. Nutrient ratios of the major plant nurtrients were found to be approximately the same as the nutrient ratios in the sewage effluent. Annual N and P uptake rates of hyacinth cultured in sewage effluent were found to be in the range of 1176 to 1193 kg N/ha yr and 321 to 387 kg P/ha yr, respectively.

  20. Comparison of biological and chemical phosphorus removals in continuous and sequencing batch reactors

    SciTech Connect

    Ketchum, L.H.; Irvine, R.L. Jr.; Breyfogle, R.E.; Manning, J.F. Jr.

    1987-01-01

    A full-scale study of phosphorus removal has been conducted at Culver using continuous-flow operation, SBR operation, and several different chemical treatment schemes. A full-scale demonstration of SBR biological phosphorus removal also has been shown to be effective. Four contributing groups of organisms and their roles in biological SBR phosphorus removal have been described: denitrifying organisms, fermentation product-manufacturing organisms, phosphorus- accumulating organisms, and aerobic autotrophs and heterotrophs. The SBR can provide the proper balance of anoxic, anaerobic, and aerobic conditions to allow these group of organisms to successfully remove phosphorus biologically, without chemical addition. Treatment results using various chemicals for phosphorus removal, both during conventional, continuous-flow operation and after the plant was converted for SBR operation, have also been provided for comparison. Effluent phosphorus concentrations were almost identical for each period, except for the period when phosphorus was removed biologically and without any chemical addition when effluent phosphorus concentrations were the lowest. These removals were made as a result of settling alone; no tertiary rapid stand filter was used or required.

  1. Biomass production and nutrient removal potential of water hyacinth cultured in sewage effluent

    SciTech Connect

    Reddy, K.R.; Hueston, F.M.; McKim, T.

    1985-05-01

    Growth and nutrient uptake of water hyacinth (Eichhornia crassipes (Mart) Solms) cultured in sewage effluent were measured over a period of 1 year in a prototype wastewater treatment system which has been in operation at Walt Disney World near Orlando, Florida. Annual productivity of water hyacinth cultured in primary sewage effluent (Channel II) was found to be in the range of 5 to 27 g dry wt m/sup -2/ day/sup -1/ (23.6 dry tons acre/sup -1/ yr/sup -1/). Average growth rate during the months of May through October 1982 for hyacinth cultured in Channel II (primary sewage effluent) and Channel I (treated primary sewage effluent leaving Channel II) was about 16 g dry wt m/sup -2/ day/sup -1/ (27 dry tons acre/sup -1/ yr/sup -1/), compared to the growth rate of 13 g dry wt m/sup -2/ day/sup -1/ (22 dry tons acre/sup -1/ yr/sup -1/) for hyacinths cultured in secondary sewage effluent. Plants cultured in secondary sewage effluent generally had longer roots than the plants cultured in primary sewage effluent. A significant relationship was observed between the growth rate of hyacinth and the solar radiation. Nitrogen and P concentration of the plant tissue were higher in the hyacinths cultured during winter months compared to the plants grown in summer months. Average N and P concentration of the plants cultured in primary sewage effluent were found to be 3.7 percent N and 0.94 percent P, respectively, while the plants cultured in secondary sewage effluent had a total N and P content of 2.8 percent N and 0.79 percent P. Nutrient ratios of the major plant nutrients were found to be approximately the same as the nutrient ratios in the sewage effluent. Annual N and P uptake rates of hyacinth cultured in sewage effluent were found to be in the range of 1176 to 1193 kg N ha/sup -1/ yr/sup -1/ and 321 to 387 kg P ha/sup -1/ yr/sup -1/, respectively.

  2. Efficient nutrient removal from swine manure in a tubular biofilm photo-bioreactor using algae-bacteria consortia.

    PubMed

    González, C; Marciniak, J; Villaverde, S; León, C; García, P A; Muñoz, R

    2008-01-01

    Concentrated animals feeding operations (CAFOs) often pose a negative environmental impact due to the uncontrolled spreading of manure into soils that ends up in the release of organic matter and nutrients into water bodies. Conventional aerobic methods treating CAFOs wastewater require intensive oxygenation, which significantly increases the operational costs. The alternative proposed in this research is the application of micro-algae based systems by taking advantage of the cost-effective in situ oxygenation via photosynthesis. A 4.9 L enclosed tubular biofilm photo-bioreactor was inoculated with an algal-bacterial consortium formed by the micro-algae Chlorella sorokiniana and a mixed bacterial culture from an activated sludge process. C. sorokiniana delivers the O(2) necessary to accomplish both organic matter and ammonium oxidation. The reactor was fed with diluted swine wastewater containing 180, 15 and 2,000 mg/L of NH(4) (+)-N, soluble P and total COD, respectively. The photo-bioreactor exhibited good and sustained nutrient removal efficiencies (up to 99% and 86% for NH(4) (+) and PO(4) (3-), respectively) while total COD was removed up to 75% when the biofilm was properly established. Liquid superficial velocities up to 0.4 m/s (achieved by culture broth recirculation) hindered the formation of a stable biofilm, while operation at velocities lower than 0.1 m/s supported stable process performance. The high shear stress imposed by the centrifugal recirculation pump disintegrated the large aggregates detached from the biofilm, which resulted in a poor settling performance and therefore poor COD removal efficiencies. Enclosed biofilm photo-bioreactors therefore offer a potentially more economical alternative to conventional tertiary treatments process.

  3. Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.

    PubMed

    Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2014-02-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4(2-)/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production and oxygen demand. Recently, the SANI(®) process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30 °C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0 mg P/mg S. There were no conventional PAOs in the sludge.

  4. Biological regeneration of ferric (Fe3+) solution during desulphurisation of gaseous streams: effect of nutrients and support material.

    PubMed

    Mulopo, Jean; Schaefer, L

    2015-01-01

    This paper evaluates the biological regeneration of ferric Fe3+ solution during desulphurisation of gaseous streams. Hydrogen sulphide (H2S) is absorbed into aqueous ferric sulphate solution and oxidised to elemental sulphur, while ferric ions Fe3+ are reduced to ferrous ions Fe2+. During the industrial regeneration of Fe3+, nutrients and trace minerals usually provided in a laboratory setup are not present and this depletion of nutrients may have a negative impact on the bacteria responsible for ferrous iron oxidation and may probably affect the oxidation rate. In this study, the effect of nutrients and trace minerals on ferrous iron oxidation have been investigated and the results showed that the presence of nutrients and trace minerals affects the efficiency of bacterial Fe2+oxidation. The scanning electron microscopy analysis of the geotextile support material was also conducted and the results showed that the iron precipitate deposits appear to play a direct role on the bacterial biofilm formation.

  5. 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

  6. Imaging through a biological medium using speckle noise removal techniques

    NASA Astrophysics Data System (ADS)

    Cuddihy, Aoife; Hennelly, Bryan; Naughton, Thomas J.; Markham, Charles; O'Neill, Raymond

    2007-07-01

    Experimental work has been carried out to extend a recently introduced technique, namely non-invasive optical imaging by speckle ensemble (NOISE), to non-invasively image a structure embedded beneath a 2.5mm thick layer of biological tissue (bacon). This method uses a microlens array and a coherent light source in transmission mode. Image reconstruction is achieved by averaging individual images from selected microlenses, thus reducing the speckle noise created due to the tissue layers. We advance on previous work by use of a more powerful laser source (75mW HeNe) and a higher resolution camera (2048x2048). Further advancement led to the introduction of a rotating ground glass diffuser into the system, which additionally reduced the speckle noise and enhanced the image quality. Leading on from this, an even simpler method of imaging beneath biological tissue is devised using the same setup, but without the microlens array. The principle is the same as the NOISE technique, except instead of taking a spatial average of independent speckle patterns a time average is taken within the exposure time of the CCD camera. Experimental results and comparisons are provided that support the theory.

  7. Corn grain, stover yield and nutrient removal validations at regional partnership sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn (Zea mays, L.) stover has been identified as a major feedstock for cellulosic bioenergy. This report summarizes grain and stover yield as well as N, P, and K removal at several Sun Grant Regional Partnership (SGRP) sites. National Agricultural Statistical Service (NASS) grain yields were used t...

  8. Removal of nutrients from septic tank effluent with baffle subsurface-flow constructed wetlands.

    PubMed

    Cui, Lihua; Ouyang, Ying; Yang, Weizhi; Huang, Zhujian; Xu, Qiaoling; Yu, Guangwei

    2015-04-15

    Three new baffle flow constructed wetlands (CWs), namely the baffle horizontal flow CW (Z1), baffle vertical flow CW (Z2) and baffle hybrid flow CW (Z3), along with one traditional horizontal subsurface flow CW (Z4) were designed to test the removal efficiency of nitrogen (N) and phosphorus (P) from the septic tank effluent under varying hydraulic retention times (HRTs). Results showed that the optimal HRT was two days for maximal removal of N and P from the septic tank effluent among the four CWs. At this HRT, the Z1, Z2, Z3 and Z4 CWs removed, respectively, 49.93, 58.50, 46.01 and 44.44% of TN as well as 87.82, 93.23, 95.97 and 91.30% of TP. Our study further revealed that the Z3 CW was the best design for overall removal of N and P from the septic tank effluent due to its hybrid flow directions with better oxygen supply inside the CW system.

  9. Osmotic versus conventional membrane bioreactors integrated with reverse osmosis for water reuse: Biological stability, membrane fouling, and contaminant removal.

    PubMed

    Luo, Wenhai; Phan, Hop V; Xie, Ming; Hai, Faisal I; Price, William E; Elimelech, Menachem; Nghiem, Long D

    2017-02-01

    This study systematically compares the performance of osmotic membrane bioreactor - reverse osmosis (OMBR-RO) and conventional membrane bioreactor - reverse osmosis (MBR-RO) for advanced wastewater treatment and water reuse. Both systems achieved effective removal of bulk organic matter and nutrients, and almost complete removal of all 31 trace organic contaminants investigated. They both could produce high quality water suitable for recycling applications. During OMBR-RO operation, salinity build-up in the bioreactor reduced the water flux and negatively impacted the system biological treatment by altering biomass characteristics and microbial community structure. In addition, the elevated salinity also increased soluble microbial products and extracellular polymeric substances in the mixed liquor, which induced fouling of the forward osmosis (FO) membrane. Nevertheless, microbial analysis indicated that salinity stress resulted in the development of halotolerant bacteria, consequently sustaining biodegradation in the OMBR system. By contrast, biological performance was relatively stable throughout conventional MBR-RO operation. Compared to conventional MBR-RO, the FO process effectively prevented foulants from permeating into the draw solution, thereby significantly reducing fouling of the downstream RO membrane in OMBR-RO operation. Accumulation of organic matter, including humic- and protein-like substances, as well as inorganic salts in the MBR effluent resulted in severe RO membrane fouling in conventional MBR-RO operation.

  10. Molecular characterization of denitrifying bacteria isolated from the anoxic reactor of a modified DEPHANOX plant performing enhanced biological phosphorus removal.

    PubMed

    Zafiriadis, Ilias; Ntougias, Spyridon; Mirelis, Paraskevi; Kapagiannidis, Anastasios G; Aivasidis, Alexander

    2012-06-01

    Enhanced Biological Phosphorus Removal (EBPR) under anoxic conditions was achieved using a Biological Nutrient Removal (BNR) system based on a modification of the DEPHANOX configuration. Double-probe Fluorescence in Situ Hybridization (FISH) revealed that Polyphosphate Accumulating Organisms (PAOs) comprised 12.3 +/- 3.2% of the total bacterial population in the modified DEPHANOX plant. The growing bacterial population on blood agar and Casitone Glycerol Yeast Autolysate agar (CGYA) medium was 16.7 +/- 0.9 x 10(5) and 3.0 +/- 0.6 x 10(5) colony forming units (cfu) mL(-1) activated sludge, respectively. A total of 121 bacterial isolates were characterized according to their denitrification ability, with 26 bacterial strains being capable of reducing nitrate to gas. All denitrifying isolates were placed within the alpha-, beta-, and gamma-subdivisions of Proteobacteria and the family Flavobacteriaceae. Furthermore, a novel denitrifying bacterium within the genus Pseudomonas was identified. This is the first report on the isolation and molecular characterization of denitrifying bacteria from EBPR sludge using a DEPHANOX-type plant.

  11. Comparison between a moving bed bioreactor and a fixed bed bioreactor for biological phosphate removal and denitrification.

    PubMed

    Choi, H J; Lee, A H; Lee, S M

    2012-01-01

    Moving bed bioreactors (MBBR) and fixed bed bioreactors (FBBR) were compared for biological phosphorus removal and denitrification. The sorption denitrification P-elimination (S-DN-P) process was selected for this study. Results indicated that all nutrients were removed by the FBBR process compared with the MBBR process: 19.8% (total COD), 35.5% (filtered COD), 27.6% (BOD(5)), 62.2% (acetate), 78.5% (PO(4)-P), and 54.2% (NO(3)-N) in MBBR; 49.7% (total COD), 54.0% (filtered COD), 63.2% (BOD(5)), 99.6% (acetate), 98.6% (PO(4)-P), and 75.9% (NO(3)-N) in FBBR. The phosphate uptake and NO(3)-N decomposition in the FBBR process during the denitrification phase were much higher than for the MBBR process despite being of shorter duration. Results obtained from this study are helpful in elucidating the practical implications of using MBBR and FBBR for the removal of bio-P and denitrification from wastewater.

  12. Nutrient availability affects pigment production but not growth in lichens of biological soil crusts

    USGS Publications Warehouse

    Bowker, M.A.; Koch, G.W.; Belnap, J.; Johnson, N.C.

    2008-01-01

    Recent research suggests that micronutrients such as Mn may limit growth of slow-growing biological soil crusts (BSCs) in some of the drylands of the world. These soil surface communities contribute strongly to arid ecosystem function and are easily degraded, creating a need for new restoration tools. The possibility that Mn fertilization could be used as a restoration tool for BSCs has not been tested previously. We used microcosms in a controlled greenhouse setting to investigate the hypothesis that Mn may limit photosynthesis and consequently growth in Collema tenax, a dominant N-fixing lichen found in BSCs worldwide. We found no evidence to support our hypothesis; furthermore, addition of other nutrients (primarily P, K, and Zn) had a suppressive effect on gross photosynthesis (P = 0.05). We also monitored the growth and physiological status of our microcosms and found that other nutrients increased the production of scytonemin, an important sunscreen pigment, but only when not added with Mn (P = 0.01). A structural equation model indicated that this effect was independent of any photosynthesis-related variable. We propose two alternative hypotheses to account for this pattern: (1) Mn suppresses processes needed to produce scytonemin; and (2) Mn is required to suppress scytonemin production at low light, when it is an unnecessary photosynthate sink. Although Mn fertilization does not appear likely to increase photosynthesis or growth of Collema, it could have a role in survivorship during environmentally stressful periods due to modification of scytonemin production. Thus, Mn enrichment should be studied further for its potential to facilitate BSC rehabilitation. ?? 2008 Elsevier Ltd.

  13. Effect of different plant species on nutrient removal and rhizospheric microorganisms distribution in horizontal-flow constructed wetlands.

    PubMed

    Meng, Panpan; Hu, Wenrong; Pei, Haiyan; Hou, Qingjie; Ji, Yan

    2014-01-01

    Three macrophyte species, Phragmites australis, Arundo donax L., and Typha latifolia L. have been separately grown in a horizontal-flow (HF) constructed wetland (CW) fed with domestic wastewater to investigate effects of plant species on nutrient removal and rhizospheric microorganisms. All the three mesocosms have been in operation for eight months under the loading rates of 1.14 g Nm(-2) d(-1) and 0.014gP m(-2) d(-1). Appropriately 34-43% phosphorus (P) was removed in HF CWs, and no distinct difference was found among the plants. In the growing season, A. donax L. removed 31.19 gm(-2) of nitrogen (N), followed by P. australis (29.96 g m(-2)), both of which were significantly higher than T. latifolia L. (7.21 g m(-2). Depending on the species, plants absorbed 1.73-7.15% of the overall N, and 0.06-0.56% of the P input. At least 10 common dominant microorganisms were found in the rhizosphere of all the three plants, and 6 of the 10 kinds of bacteria had close relationship with denitrifying bacteria, implying that denitrifiers were dominant microorganism distributed in rhizosphere of wetland plants.

  14. Effect of algae growth on aerobic granulation and nutrients removal from synthetic wastewater by using sequencing batch reactors.

    PubMed

    Huang, Wenli; Li, Bing; Zhang, Chao; Zhang, Zhenya; Lei, Zhongfang; Lu, Baowang; Zhou, Beibei

    2015-03-01

    The effect of algae growth on aerobic granulation and nutrients removal was studied in two identical sequencing batch reactors (SBRs). Sunlight exposure promoted the growth of algae in the SBR (Rs), forming an algal-bacterial symbiosis in aerobic granules. Compared to the control SBR (Rc), Rs had a slower granulation process with granules of loose structure and smaller particle size. Moreover, the specific oxygen uptake rate was significantly decreased for the granules from Rs with secretion of 25.7% and 22.5% less proteins and polysaccharides respectively in the extracellular polymeric substances. Although little impact was observed on chemical oxygen demand (COD) removal, algal-bacterial symbiosis deteriorated N and P removals, about 40.7-45.4% of total N and 44% of total P in Rs in contrast to 52.9-58.3% of TN and 90% of TP in Rc, respectively. In addition, the growth of algae altered the microbial community in Rs, especially unfavorable for Nitrospiraceae and Nitrosomonadaceae.

  15. In situ biological resources: Soluble nutrients and electrolytes in carbonaceous asteroids/meteorites. Implications for astroecology and human space populations

    NASA Astrophysics Data System (ADS)

    Mautner, Michael N.

    2014-12-01

    Ecosystems in space will need in-situ bioavailable nutrients. The measured nutrients in meteorites allow experiment-based estimates of nutrients in asteroids, and of the biomass and populations that can be derived from these in situ bioresources. In this respect, we found that carbonaceous chondrite meteorites can support microorganisms and plant cultures, suggesting that similar asteroid materials are also biologically fertile. The sustainable biomass and populations are determined by the available resource materials, their yields of nutrients and biomass, the biomass needed to support human populations, the duration of the ecosystem, and wastage. The bioavailable C, N, and electrolytes in carbonaceous chondrite meteorites vary as CM2>CR2>CV3>CO3>CK4>CK5 in correlation with petrologic type, including aqueous alteration. Their average bioavailable C, N, K and P can yield 2.4, 3.5, 2.5, and 0.08 g biomass/kg resource material, respectively, showing phosphorus as the limiting nutrient. On this basis, soluble nutrients in a 100 km radius, 1019 kg resource asteroid can sustain an ecosystem of 108 kg biomass and a human population of 10,000 for >109 years, and its total nutrient contents can sustain a population of one million, by replacing a wastage of 1% of the biomass per year. Overall, the total nutrient contents of the 1022 kg carbonaceous asteroids can yield a biomass of 1020 kg that supports a steady-state human population of one billion during the habitable future of the Solar System, contributing a time-integrated biomass of 1022 kg-years. These astroecology estimates use experimental data on nutrients in asteroids/meteorites to quantify the sustainable biomass and human populations in this and similar solar systems.

  16. Investigation into ammonia stress on Cyperus alternifolius and its impact on nutrient removal in microcosm experiments.

    PubMed

    Tao, Wendong; Han, Jianqiu; Li, Hanyan

    2015-11-01

    Ammonia stress on plants has been investigated at discrete ammonia concentrations in constructed wetlands. This study introduced a Gaussian model to simulate the kinetics of ammonia stress and investigated reversible and irreversible ammonia stress on Cyperus alternifolius in wetland-like microcosms. Ammonia stress on plant weight increase and oxygen release potential started at weekly ammonia concentrations of 27 and 28 mg N/L, reached 50% inhibition at 178 and 158 mg N/L, and resulted in lethal effects at 311 and 303 mg N/L, respectively. The stress of one-time ammonia concentrations up to 400 mg N/L could be reversible. Ammonia concentrations constantly above 219 mg N/L exerted irreversible stress. In the microcosms with ammonia concentrations above the 50% inhibition levels, plants played a minor role in nitrogen removal. Nitrogen removal performance was not affected considerably by ammonia stress. Orthophosphate removal was suppressed by ammonia stress due to less plant uptake. Design and operation of constructed wetlands should consider wastewater ammonia concentration so that the integrity of constructed wetland ecosystems can be maintained.

  17. A tracer study for assessing the interactions between hydraulic retention time and transport processes in a wetland system for nutrient removal.

    PubMed

    Chang, Ni-Bin; Xuan, Zhemin; Wanielista, Martin P

    2012-03-01

    In this study, a new-generation subsurface upflow wetland (SUW) system packed with the unique sorption media was introduced for nutrient removal. To explore the interface between hydraulic and environmental performance, a tracer study was carried out in concert with a transport model to collectively provide hydraulic retention time (7.1 days) and compelling evidence of pollutant fate and transport processes. Research findings indicate that our pollution-control media demonstrate smooth nutrient removal efficiencies across different sampling port locations given the appropriate size distribution conversant with the anticipated hydraulic patterns and layered structure among the sorption media components. The sizable capacity for nutrient removal in this bioprocess confirms that SUW is a promising substitute for an extension of traditional on-site wastewater treatment systems.

  18. 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.

  19. Development of a 2-sludge, 3-stage system for nitrogen and phosphorous removal from nutrient-rich wastewater using granular sludge and biofilms.

    PubMed

    Zhou, Yan; Pijuan, Maite; Yuan, Zhiguo

    2008-06-01

    A novel 2-sludge 3-stage process using a combination of granular sludge and biofilm was developed to achieve biological removal of nitrogen and phosphorus from nutrient-rich wastewater. The system consists of a granular sequencing batch reactor (SBR) working under alternating anaerobic/anoxic conditions supplemented with a short aerobic phase and an aerobic biofilm SBR. The wastewater is first fed to the granular SBR reactor, where easily biodegradable carbon sources are taken up primarily by polyphosphate accumulating organisms (PAOs). The supernatant resulting from quick settling of the granular sludge is then fed to the biofilm SBR for nitrification, which produces oxidized nitrogen that is returned to the granular reactor for simultaneous denitrification and phosphorus removal. While maximizing the utilization of organic substrates and reducing operational costs, as do other 2-sludge processes previously reported in literature, the proposed system solves the bottleneck problem of traditional 2-sludge systems, namely high effluent ammonia concentration, due to its high-volume exchange ratios. An ammonia oxidation rate of 32 mg N/Lh was achieved in the biofilm SBR, which produced nitrite as the final product. This nitrite stream was found to cause major inhibition on the anoxic P uptake and also to result in the accumulation of N(2)O. These problems were solved by feeding the nitrite-containing stream continuously to the granular reactor in the anoxic phase. With a nitrogen and phosphorus removal efficiency of 81% and 94%, respectively, the system produces an effluent that is suitable for land irrigation from a wastewater stream containing 270 mg N/L of total nitrogen and 40 mg P/L of total phosphorus.

  20. 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

  1. A diatom-based biological condition gradient (BCG) approach for assessing impairment and developing nutrient criteria for streams.

    PubMed

    Hausmann, Sonja; Charles, Donald F; Gerritsen, Jeroen; Belton, Thomas J

    2016-08-15

    Over-enrichment leading to excess algal growth is a major problem in rivers and streams. Regulations to protect streams typically incorporate nutrient criteria, concentrations of phosphorus and nitrogen that should not be exceeded in order to protect biological communities. A major challenge has been to develop an approach for both categorizing streams based on their biological conditions and determining scientifically defensible nutrient criteria to protect the biotic integrity of streams in those categories. To address this challenge, we applied the Biological Condition Gradient (BCG) approach to stream diatom assemblages to develop a system for categorizing sites by level of impairment, and then examined the related nutrient concentrations to identify potential nutrient criteria. The six levels of the BCG represent a range of ecological conditions from natural (1) to highly disturbed (6). A group of diatom experts developed a set of rules and a model to assign sites to these levels based on their diatom assemblages. To identify potential numeric nutrient criteria, we explored the relation of assigned BCG levels to nutrient concentrations, other anthropogenic stressors, and possible confounding variables using data for stream sites in New Jersey (n=42) and in surrounding Mid-Atlantic states, USA (n=1443). In both data sets, BCG levels correlated most strongly with total phosphorus and the percentage of forest in the watershed, but were independent of pH. We applied Threshold Indicator Taxa Analysis (TITAN) to determine change-points in the diatom assemblages along the BCG gradient. In both data sets, statistically significant diatom changes occurred between BCG levels 3 and 4. Sites with BCG levels 1 to 3 were dominated by species that grow attached to surfaces, while sites with BCG scores of 4 and above were characterized by motile diatoms. The diatom change-point corresponded with a total phosphorus concentration of about 50μg/L.

  2. Comparison of the biological NH3 removal characteristics among four inorganic packing materials.

    PubMed

    Hirai, M; Kamamoto, M; Yani, M; Shoda, M

    2001-01-01

    Four inorganic packing materials were evaluated in terms of their availability as a packing material of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological NH3 removal characteristics and some physical properties. Porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calculated soil (D) were used. The superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of NH3 per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately = C > B > or = D. Packing materials A and C with high porosity, maximum water content, and suitable mean pore diameter showed excellent removal capacity.

  3. Bacterial composition and nutrient removal with a novel PIA-A(2)/O sewage treatment.

    PubMed

    Dong, Li; Yahong, Luo; Yanan, Cai; Huiping, Zeng; Jie, Zhang

    2016-01-01

    A novel post intermittent aeration anaerobic-anoxic-oxic (PIA-A(2)/O) process was developed to integrate shortcut nitrification-denitrification with denitrifying phosphorus (P) removal for domestic sewage treatment. With the transformation in configuration and phased start-up strategy, the nitritation rate and the ratio of denitrifying phosphorus accumulating organisms to phosphorus accumulating organisms (DPAO/PAO) were enhanced greatly to 88.2% and 83.9-91.7% in the PIA-A(2)/O process, respectively. Improved total nitrogen and phosphorus removal were achieved at long sludge retention time and low aeration. High sludge activity was maintained through the periodic selection of the additional intermittent aeration zone. High-throughput sequencing revealed that Bacteroidetes (38.96%), Proteobacteria (33.59%), TM7 (4.53%), Chloroflexi (3.09%), and Firmicutes (2.49%) were the dominant phyla in the resultant bacterial community. Abundant anaerobic and facultative bacteria conducive to excess sludge reduction were generated by this process. Potential DPAOs involve the genera of Brevundimonas, Brachymonas, Steroidobacter, Haliscomenobacter, and Rhodocyclus.

  4. Bioremediation efficiency in the removal of dissolved inorganic nutrients by the red seaweed, Porphyra yezoensis, cultivated in the open sea.

    PubMed

    He, Peimin; Xu, Shannan; Zhang, Hanye; Wen, Shanshan; Dai, Yongjing; Lin, Senjie; Yarish, Charles

    2008-02-01

    The bioremediation capability and efficiency of large-scale Porphyra cultivation in the removal of inorganic nitrogen and phosphorus from open sea area were studied. The study took place in 2002-2004, in a 300 ha nori farm along the Lusi coast, Qidong County, Jiangsu Province, China, where the valuable rhodophyte seaweed Porphyra yezoensis has been extensively cultivated. Nutrient concentrations were significantly reduced by the seaweed cultivation. During the non-cultivation period of P. yezoensis, the concentrations of NH4-N, NO2-N, NO3-N and PO4-P were 43-61, 1-3, 33-44 and 1-3 micromol L(-1), respectively. Within the Porphyra cultivation area, the average nutrient concentrations during the Porphyra cultivation season were 20.5, 1.1, 27.9 and 0.96 micromol L(-1) for NH4-N, NO2-N, NO3-N and PO4-P, respectively, significantly lower than in the non-cultivation season (p<0.05). Compared with the control area, Porphyra farming resulted in the reduction of NH4-N, NO2-N, NO3-N and PO4-P by 50-94%, 42-91%, 21-38% and 42-67%, respectively. Nitrogen and phosphorus contents in dry Porphyra thalli harvested from the Lusi coast averaged 6.3% and 1.0%, respectively. There were significant monthly variations in tissue nitrogen content (p<0.05) but not in tissue phosphorus content (p>0.05). The highest tissue nitrogen content, 7.65% in dry wt, was found in December and the lowest value, 4.85%, in dry wt, in April. The annual biomass production of P. yezoensis was about 800 kg dry wt ha(-1) at the Lusi Coast in 2003-2004. An average of 14708.5 kg of tissue nitrogen and 2373.5 kg of tissue phosphorus in P. yezoensis biomass were harvested annually from 300 ha of cultivation from Lusi coastal water. These results indicated that Porphyra efficiently removed excess nutrient from nearshore eutrophic coastal areas. Therefore, large-scale cultivation of P. yezoensis could alleviate eutrophication in coastal waters economically.

  5. Understanding the granulation process of activated sludge in a biological phosphorus removal sequencing batch reactor.

    PubMed

    Wu, Chang-Yong; Peng, Yong-Zhen; Wang, Ran-Deng; Zhou, Yue-Xi

    2012-02-01

    The granulation of activated sludge was investigated using two parallel sequencing batch reactors (SBRs) operated in biological nitrogen and phosphorus removal conditions though the reactor configuration and operating parameters did not favor the granulation. Granules were not observed when the SBR was operated in biological nitrogen removal period for 30d. However, aerobic granules were formed naturally without the increase of aeration intensity when enhanced biological phosphorus removal (EBPR) was achieved. It can be detected that plenty of positive charged particles were formed with the release of phosphorus during the anaerobic period of EBPR. The size of the particles was about 5-20 μm and their highest positive ζ potential was about 73 mV. These positive charged particles can stimulate the granulation. Based on the experimental results, a hypothesis was proposed to interpret the granulation process of activated sludge in the EBPR process in SBR. Dense and compact subgranules were formed stimulated by the positive charged particles. The subgranules grew gradually by collision, adhesion and attached growth of bacteria. Finally, the extrusion and shear of hydrodynamic shear force would help the maturation of granules. Aerobic granular SBR showed excellent biological phosphorus removal ability. The average phosphorus removal efficiency was over 95% and the phosphorus in the effluent was below 0.50 mg L(-1) during the operation.

  6. Fouling of enhanced biological phosphorus removal-membrane bioreactors by humic-like substances.

    PubMed

    Poorasgari, Eskandar; König, Katja; Fojan, Peter; Keiding, Kristian; Christensen, Morten Lykkegaard

    2014-12-01

    Fouling by free extracellular polymeric substances was studied in an enhanced biological phosphorus removal-membrane bioreactor. It was demonstrated that the free extracellular polymeric substances, primarily consisting of humic-like substances, were adsorbed to the membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant. Infrared analyses indicated the presence of the humic-like substances on the membrane's active surface after filtration of the free extracellular polymeric substances suspension. Scanning electron microscopy showed the presence of a gel layer on the membrane surface after filtration of the free extracellular polymeric substances suspension. The gel layer caused a significant decline in water flux. This layer was not entirely removed by a backwashing, and the membrane's water flux could not be re-established. The membrane used in the enhanced biological phosphorus removal-membrane bioreactor plant showed infrared spectra similar to that fouled by the free extracellular polymeric substances suspension in the laboratory. Thus, the results of this study show the importance of humic-like substances in irreversible fouling of enhanced biological phosphorus removal-membrane bioreactor systems.

  7. [Review on the main microorganisms and their metabolic mechanisms in enhanced biological phosphorus removal (EBPR) systems].

    PubMed

    Sun, Xue; Zhu, Wei-Jing; Wang, Liang; Wu, Wei-Xiang

    2014-03-01

    Enhanced biological phosphorus removal (EBPR) process is applied widely for removing phosphorus from wastewater. Studies on functional microorganisms and their metabolic mechanisms are fundamental to effective regulation for stable operation and performance improvement of EBPR process. Two main types of microorganisms in EBPR systems, polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) were selected to summarize their metabolic mechanisms such as substrate uptake mechanisms, glycogen degradation pathways, extent of TCA cycle involvement and metabolic similarity between PAOs and GAOs. Application of molecular biology techniques in microbiology and metabolic mechanisms involved in the EBPR system was evaluated. Potential future research areas for the EBPR system and process optimization were also proposed.

  8. Simultaneous removal of nanosilver and fullerene in sequencing batch reactors for biological wastewater treatment.

    PubMed

    Yang, Yu; Wang, Yifei; Hristovski, Kiril; Westerhoff, Paul

    2015-04-01

    Increasing use of engineered nanomaterials (ENMs) inevitably leads to their potential release to the sewer system. The co-removal of nano fullerenes (nC60) and nanosilver as well as their impact on COD removal were studied in biological sequencing batch reactors (SBR) for a year. When dosing nC60 at 0.07-2mgL(-1), the SBR removed greater than 95% of nC60 except for short-term interruptions occurred (i.e., dysfunction of bioreactor by nanosilver addition) when nC60 and nanosilver were dosed simultaneously. During repeated 30-d periods of adding both 2 mg L(-1) nC60 and 2 mg L(-1) nanosilver, short-term interruption of SBRs for 4d was observed and accompanied by (1) reduced total suspended solids in the reactor, (2) poor COD removal rate as low as 22%, and (3) decreased nC60 removal to 0%. After the short-term interruption, COD removal gradually returned to normal within one solids retention time. Except for during these "short-term interruptions", the silver removal rate was above 90%. A series of bottle-point batch experiments was conducted to determine the distribution coefficients of nC60 between liquid and biomass phases. A linear distribution model on nC60 combined with a mass balance equation simulated well its removal rate at a range of 0.07-0.76 mg L(-1) in SBRs. This paper illustrates the effect of "pulse" inputs (i.e., addition for a short period of time) of ENMs into biological reactors, demonstrates long-term capability of SBRs to remove ENMs and COD, and provides an example to predict the removal of ENMs in SBRs upon batch experiments.

  9. Embedding constructed wetland in sequencing batch reactor for enhancing nutrients removal: A comparative evaluation.

    PubMed

    Liu, Ranbin; Zhao, Yaqian; Zhao, Jinhui; Xu, Lei; Sibille, Caroline

    2017-05-01

    In the present study, a novel green bio-sorption reactor (GBR) was firstly proposed and preliminarily investigated by embedding constructed wetland (CW) into the aeration tank of the conventional activated sludge (CAS). This integrated novel system owns the striking features of adding carriers of wetland substrate (i.e. the dewatered alum sludge in this case) in CAS for robust phosphorus adsorption and enriching the biomass. Meanwhile, the "green" feature of this GBR imparted aesthetic value of CW to the CAS system. The preliminary 3-month trial of GBR based on a sequencing batch reactor (GB-SBR) with diluted piggery wastewater demonstrated an average removal of 96%, 99% and 90% for BOD, TP and TN, respectively. The comparison with moving bed biofilm reactor (MBBR) and integrated fixed-film activated sludge (IFAS) reflected the advantages of GBR over purification performance, aesthetic value and potential carbon sink. Moreover, the carriers used in the GBR are dewatered alum sludge which is in line with the policy of "recycle, reuse and reduce". Overall, this GBR undoubtedly offered a more sustainable and economical solution for retrofitting the aging CAS.

  10. Comparison of Three Bed Packings for the Biological Removal of Nitric Oxide from Gas Streams

    SciTech Connect

    Lee, Brady Douglas; Flanagan, W. P.; Barnes, Charles Marshall; Barrett, Karen B.; Zaccardi, Larry Bryan; Apel, William Arnold

    2000-10-01

    Environmental and health issues coupled with increasingly stringent nitrogen oxide (NOx) emission standards indicates a need for the development of alternative low-cost technologies for the removal of NOx from gas streams. Biological NOx conversion offers promise as a novel treatment method. Thermophilic denitrifying bacteria indigenous to composts and soils are capable of converting NOx to environmentally benign nitrogen via a dissimilatory reductive pathway. The present study compares the performance of three bioreactor packing materials (compost, perlite, and biofoam) for the removal of nitric oxide (NO) from a simulated wet-scrubbed combustion gas. Although all three materials performed well (>85% NO removal) at residence times of 70-80 seconds, the compost performed better than the other materials at shorter residence times (13-44 seconds). The perlite and biofoam materials, however, both offer long-term thermal stability and lower pressure drop compared with compost. The feasibility of biological NOx conversion processes will depend on the combined factors of NOx removal ability and pressure drop. The results presented here suggest that the compost, perlite and biofoam systems, subject to further optimization, offer potential for the biological removal of NOx from gas streams.

  11. Nitrate-reducing, sulfide-oxidizing bacteria as microbial oxidants for rapid biological sulfide removal.

    PubMed

    De Gusseme, Bart; De Schryver, Peter; De Cooman, Michaël; Verbeken, Kim; Boeckx, Pascal; Verstraete, Willy; Boon, Nico

    2009-01-01

    The emission of hydrogen sulfide into the atmosphere of sewer systems induces the biological production of sulfuric acid, causing severe concrete corrosion. As a possible preventive solution, a microbial consortium of nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB) was enriched in a continuously stirred tank reactor in order to develop a biological technique for the removal of dissolved sulfide. The consortium, dominated by Arcobacter sp., was capable of removing 99% of sulfide. Stable isotope fractioning of the sulfide indicated that the oxidation was a biological process. The capacity of the NR-SOB consortium for rapid removal of sulfide was demonstrated by using it as an inoculum in synthetic and real sewage. Removal rates up to 52 mg sulfide-S g VSS(-1) h(-1) were achieved, to our knowledge the highest removal rate reported so far for freshwater species in the absence of molecular oxygen. Further long-term incubation experiments revealed the capacity of the bacteria to oxidize sulfide without the presence of nitrate, suggesting that an oxidized redox reserve is present in the culture.

  12. Biological Ammonia Removal: From Theory to Case Studies in 20 Minutes

    EPA Science Inventory

    This presentation documents the results of two pilot-scale treatment studies, in Ohio and Iowa, that investigated the biological removal of ammonia from ground water. Influent ammonia concentrations in the Ohio and Iowa studies averaged 1.3 and 3.3 mg/L - N, respectively. Both ...

  13. A hypothesis on Microthrix parvicella proliferation in biological nutrient removal activated sludge systems with selector tanks.

    PubMed

    Noutsopoulos, Constantinos; Mamais, Daniel; Andreadakis, Andreas; Stams, Alfons

    2012-05-01

    The objective of this study was to evaluate the ability of Microthrix parvicella for long-chain fatty acids uptake under anaerobic, anoxic, and aerobic conditions as well as its ability to utilize volatile fatty acids and long-chain fatty acids under anoxic and aerobic conditions. According to the results, a hypothesis on the competition between floc-forming microorganisms and M. parvicella for long-chain fatty acids uptake under aerobic, anoxic, and anaerobic conditions was formulated. According to this hypothesis, M. parvicella exhibits similar long-chain fatty acids uptake capacity with floc-forming microorganisms even at relatively high floc loading values that are very often imposed at selector tanks. Following this hypothesis, the failure of selector tanks to provide for an effective M. parvicella control is evidenced. Based on the experimental results, the ability of M. parvicella to utilize long-chain fatty acids with rates comparable to those of floc formers, even in anoxic conditions, in conjunction with its lower acetate utilization rates, provides a good explanation regarding its preference to slowly biodegradable organic carbon compounds.

  14. Treatment of sludge containing nitro-aromatic compounds in reed-bed mesocosms - Water, BOD, carbon and nutrient removal

    SciTech Connect

    Gustavsson, L.; Engwall, M.

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer It is necessary to improve existing and develop new sludge management techniques. Black-Right-Pointing-Pointer One method is dewatering and biodegradation of compounds in constructed wetlands. Black-Right-Pointing-Pointer The result showed high reduction of all tested parameters after treatment. Black-Right-Pointing-Pointer Plants improve degradation and Phragmites australis is tolerant to xenobiotics. Black-Right-Pointing-Pointer The amount of sludge could be reduced by 50-70%. - Abstract: Since the mid-1970s, Sweden has been depositing 1 million ton d.w sludge/year, produced at waste water treatment plants. Due to recent legislation this practice is no longer a viable method of waste management. It is necessary to improve existing and develop new sludge management techniques and one promising alternative is the dewatering and treatment of sludge in constructed wetlands. The aim of this study was to follow reduction of organic carbon, BOD and nutrients in an industrial sludge containing nitro-aromatic compounds passing through constructed small-scale wetlands, and to investigate any toxic effect such as growth inhibition of the common reed Phragmites australis. The result showed high reduction of all tested parameters in all the outgoing water samples, which shows that constructed wetlands are suitable for carbon and nutrient removal. The results also showed that P. australis is tolerant to xenobiotics and did not appear to be affected by the toxic compounds in the sludge. The sludge residual on the top of the beds contained low levels of organic carbon and is considered non-organic and could therefore be landfilled. Using this type of secondary treatment method, the amount of sludge could be reduced by 50-70%, mainly by dewatering and biodegradation of organic compounds.

  15. Impacts of membrane flux enhancers on activated sludge respiration and nutrient removal in MBRs.

    PubMed

    Iversen, Vera; Koseoglu, Hasan; Yigit, Nevzat O; Drews, Anja; Kitis, Mehmet; Lesjean, Boris; Kraume, Matthias

    2009-02-01

    This paper presents the findings of experimental investigations regarding the influence of 13 different flux enhancing chemicals (FeCl3, polyaluminium chloride, 2 chitosans, 5 synthetic polymers, 2 starches and 2 activated carbons) on respirometric characteristics and nitrification/denitrification performance of membrane bioreactor (MBR) mixed liquor. Flux enhancing chemicals are a promising method to reduce the detrimental effects of fouling phenomena via the modification of mixed liquor characteristics. However, potentially inhibiting effects of these chemicals on mixed liquor biological activity triggered the biokinetic studies (in jar tests) conducted in this work. The tested polyaluminium chloride (PACl) strongly impacted on nitrification (-16%) and denitrification rate (-43%). The biodegradable nature of chitosan was striking in endogenous and exogenous tests. Considering the relatively high costs of this chemical, an application for wastewater treatment does thus not seem to be advisable. Also, addition of one of the tested activated carbons strongly impacted on the oxygen uptake rate (-28%), nitrification (-90%) and denitrification rate (-43%), due to a decrease of pH. Results show that the changes in kLa values were mostly not significant, however, a decrease of 13% in oxygen transfer was found for sludge treated with PACl.

  16. Use of low-cost biological wastes and vermiculite for removal of chromium from tannery effluent.

    PubMed

    Sumathi, K M S; Mahimairaja, S; Naidu, R

    2005-02-01

    Biological wastes (sawdust, rice husk, coirpith and charcoal) and a naturally occurring mineral (vermiculite) have been tested for their effectiveness in removing Cr from tannery effluent through batch and column experiments. The adsorption capacities of the substrates were also evaluated using isotherm tests and computing distribution co-efficient. The sawdust exhibited a higher adsorption capacity (k = 1482 mgkg(-1)), followed by coirpith (k = 159 mgkg(-1)). The biosorbent and mineral vermiculite in columns were found very effective in removing Cr from tannery effluent. About 94% removal of Cr was achieved by a column of coirpith, and equally (93%) by a column containing a mixture of coirpith and vermiculite. This study showed that biological wastes are potential adsorbents of Cr, which could be successfully used to reduce the Cr concentrations in tannery effluent.

  17. [Oxygen-limited autotrophic nitrification and denitrification--a novel technology for biological nitrogen removal].

    PubMed

    Zhang, Dan; Xu, Hui; Li, Xiangli; Zhang, Ying; Chen, Guanxiong

    2003-12-01

    Oxygen-limited autotrophic nitrification and denitrification (OLAND) is a biological nitrogen removal process coupled with partial nitrification and anaerobic ammonium oxidation. In our study, the nitrification was blocked at nitrite stage by controlling the dissolved oxygen concentration at 0.1-0.3 mg.L-1, and then, the denitrification proceeded, with the residual ammonium at the partial nitrification stage as electron donor. As a completely autotrophic nitrification-denitrification process, the OLAND was of many advantages (e.g., low energy consumption, high nitrogen removal rate and small footprint of system), and suitable in particular for treating low COD/NH4(+)-N ratio wastewater. It has become one of the most prosperous and practicable biological nitrogen removal technologies. The recent research of OLAND was reviewed, and its microbial mechanism as well as its applicable prospect was remarked in this paper.

  18. Comparison of the biological H2S removal characteristics among four inorganic packing materials.

    PubMed

    Hirai, M; Kamamoto, M; Yani, M; Shoda, M

    2001-01-01

    Four inorganic packing materials were evaluated in terms of their availability as packing materials of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological H2S removal characteristics and some physical properties. Among porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calcinated soil (D), the superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of H2S per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately equal to C > D approximately equal to B, which is correlated with the maximum water content, porosity, and mean pore diameter.

  19. Effects of idle time on biological phosphorus removal by sequencing batch reactors.

    PubMed

    Gao, Dawen; Yin, Hang; Liu, Lin; Li, Xing; Liang, Hong

    2013-12-01

    Three identical sequencing batch reactors (SBRs) were operated to investigate the effects of various idle times on the biological phosphorus (P) removal. The idle times were set to 3 hr (R1), 10 hr (R2) and 17 hr (R3). The results showed that the idle time of a SBR had potential impact on biological phosphorus removal, especially when the influent phosphorus concentration increased. The phosphorus removal efficiencies of the R2 and R3 systems declined dramatically compared with the stable R1 system, and the P-release and P-uptake rates of the R3 system in particular decreased dramatically. The PCR-DGGE analysis showed that uncultured Pseudomonas sp. (GQ183242.1) and beta-Proteobacteria (AY823971) were the dominant phosphorus removal bacteria for the R1 and R2 systems, while uncultured gamma-Proteobacteria were the dominant phosphorus removal bacteria for the R3 system. Glycogen-accumulating organisms (GAOs), such as uncultured Sphingomonas sp. (AM889077), were found in the R2 and R3 systems. Overall, the R1 system was the most stable and exhibited the best phosphorus removal efficiency. It was found that although the idle time can be prolonged to allow the formation of intracellular polymers when the phosphorus concentration of the influent is low, systems with a long idle time can become unstable when the influent phosphorus concentration is increased.

  20. Biological N removal from wastes generated from amine-based CO2 capture: case monoethanolamine.

    PubMed

    Hauser, Ingrid; Colaço, Ana B; Skjæran, Julie A; Einbu, Aslak; Ostgaard, Kjetill; Svendsen, Hallvard F; Cervantes, Francisco J

    2013-02-01

    Large-scale amine-based CO(2) capture will generate waste containing large amounts of ammonia, in addition to contaminants such as the actual amine as well as degradation products thereof. Monoethanolamine (MEA) has been a dominant amine applied so far in this context. This study reveals how biological N removal can be achieved even in systems heavily contaminated by MEA in post- as well as pre-denitrification treatment systems, elucidating the rate-limiting factors of nitrification as well as aerobic and denitrifying biodegradation of MEA. The hydrolysis of MEA to ammonia readily occurred both in post- and pre-denitrification treatment systems with a hydraulic retention time of 7 h. MEA removal was ≥99 ± 1 % and total nitrogen removal 77 ± 10 % in both treatment systems. This study clearly demonstrates the advantage of pre-denitrification over post-denitrification for achieving biological nitrogen removal from MEA-contaminated effluents. Besides the removal of MEA, the removal efficiency of total nitrogen as well as organic matter was high without additional carbon source supplied.

  1. Effects of photoperiod on nutrient removal, biomass production, and algal-bacterial population dynamics in lab-scale photobioreactors treating municipal wastewater.

    PubMed

    Lee, Chang Soo; Lee, Sang-Ah; Ko, So-Ra; Oh, Hee-Mock; Ahn, Chi-Yong

    2015-01-01

    Effects of photoperiod were investigated in lab-scale photobioreactors containing algal-bacterial consortia to reduce organic nutrients from municipal wastewater. Under three photoperiod conditions (12 h:12 h, 36 h:12 h, and 60 h:12 h dark–light cycles), nutrient removals and biomass productions were measured along with monitoring microbial population dynamics. After a batch operation for 12 days, 59–80% carbon, 35–88% nitrogen, and 43–89% phosphorus were removed from influents, respectively. In this study, carbon removal was related positively to the length of dark cycles, while nitrogen and phosphorus removals inversely. On the contrast, the highest microbial biomass in terms of chlorophyll a, dry cell weight, and algal/bacterial rRNA gene markers was produced under the 12 h:12 h dark–light cycle among the three photoperiods. The results showed 1) simultaneous growths between algae and bacteria in the microbial consortia and 2) efficient nitrogen and phosphorus removals along with high microbial biomass production under prolonged light conditions. Statistical analyses indicated that carbon removal was significantly related to the ratio of bacteria to algae in the microbial consortia along with prolonged dark conditions (p < 0.05). In addition, the ratio of nitrogen removal to phosphorus removal decreased significantly under prolonged dark conditions (p < 0.001). These results indicated that the photoperiod condition has remarkable impacts on adjusting nutrient removal, producing microbial biomass, and altering algal-bacterial population dynamics. Therefore, the control of photoperiod was suggested as an important operating parameter in the algal wastewater treatment.

  2. Characteristics and transformations of dissolved organic nitrogen in municipal biological nitrogen removal wastewater treatment plants

    NASA Astrophysics Data System (ADS)

    Huo, Shouliang; Xi, Beidou; Yu, Honglei; Qin, Yanwen; Zan, Fengyu; Zhang, Jingtian

    2013-12-01

    Dissolved organic nitrogen (DON) represents most of the dissolved nitrogen in the effluent of biological nitrogen removal (BNR) wastewater treatment plants (WWTPs). The characteristics of wastewater-derived DON in two different WWTPs were investigated by several different methods. The major removals of DON and biodegradable dissolved organic nitrogen (BDON) along the treatment train were observed in the anaerobic process. Dissolved combined amino acids (DCAA) and dissolved free amino acids (DFAA) in the effluent accounted approximately for less than 4% and 1% of the effluent DON, respectively. Approximately half of wastewater-derived DON was capable of passing through a 1 kDa ultrafilter, and low MW DON cannot effectively be removed by BNR processes. More than 80% of effluent DON was composed of hydrophilic compounds, which stimulate algal growth. The study provided important information for future upgrading of WWTPs or the selection of DON removal systems to meet more demanding nitrogen discharge limits.

  3. Removal and fate of emerging contaminants combining biological, flocculation and membrane treatments.

    PubMed

    Melo-Guimarães, Anemir; Torner-Morales, Francisco J; Durán-Álvarez, Juan C; Jiménez-Cisneros, Blanca E

    2013-01-01

    An experimental study combining biological treatment with flocculation (F) and ultrafiltration (UF) membrane technology was conducted, separately and in combination, seeking to increase insight into the capability of such treatment processes to remove emerging contaminants (ECs). The occurrence and removal efficiencies of 17 ECs are reported for wastewater from Mexico City. Results showed that activated sludge (AS) is the predominant process for removing acidic pharmaceutical compounds, and the use of a cationic flocculant increases the biodegradability of these compounds as well as that of 4-nonylphenol. The UF process alone showed greater removal of phenolic compounds than AS. However, the contribution of flocculation to EC removal by the UF unit was fairly limited. In general, the F + AS + UF processes yielded better results than their separate use, leading to the highest removal rates of 15 of the 17 compounds. In the case of some phenolic compounds and the phthalic acid esters, a competitive sorption process between the membrane and the sludge steps seemed to take place. Bis-2-ethylhexylphthalate (DEHP) was found to be significantly sorbed onto sludge. The F + AS + UF process operated as a membrane bioreactor (MBR) using 16 gL(-1) of suspended solids in the mixed liquor (MLSS) yielded the highest removal efficiencies for the ECs tested.

  4. Biological nitrogen removal from landfill leachate by deammonification assisted by heterotrophic denitrification in a rotating biological contactor (RBC).

    PubMed

    Cema, G; Wiszniowski, J; Zabczyński, S; Zabłocka-Godlewska, E; Raszka, A; Surmacz-Górska, J

    2007-01-01

    Due to negative environmental effects of nitrogen discharge to recipients and increasingly stringent effluent standards, effective nitrogen removal is necessity. Biological methods are the simplest and cheapest way to treat wastewater; however, it may become an extremely expensive option when high influent nitrogen concentrations are measured and there is a lack of biodegradable organic carbon. Therefore, there is a great need to find new solutions and improve existing technologies. The deammonification is an excellent example of such a new process that requires considerably low amounts of organic carbon and oxygen in comparison to conventional nitrification/denitrification. The main objective of presented research was to investigate an Anammox process accompanied with autotrophic nitrification and heterotrophic denitrification in one rotating biological contactor (RBC). During the research period, it was possible to carry out the Anammox process in low temperature below 20 'C. Additionally, it was found that the process is insensitive to high nitrite concentration in the reactor, up to 100 g NO2-N m(-3), resulting only in a temporary decrease in removal rates. Furthermore, analysis of data indicated that the Stover-Kincannon model can be used for the description of ammonium and nitrite removal processes.

  5. Biological groundwater treatment for chromium removal at low hexavalent chromium concentrations.

    PubMed

    Mamais, Daniel; Noutsopoulos, Constantinos; Kavallari, Ioanna; Nyktari, Eleni; Kaldis, Apostolos; Panousi, Eleni; Nikitopoulos, George; Antoniou, Kornilia; Nasioka, Maria

    2016-06-01

    The objective of this work is to develop and evaluate biological groundwater treatment systems that will achieve hexavalent chromium reduction and total chromium removal from groundwater at hexavalent chromium (Cr(VI)) groundwater concentrations in the 0-200 μg/L range. Three lab-scale units operated, as sequencing batch reactors (SBR) under aerobic, anaerobic and anaerobic-aerobic conditions. All systems received groundwater with a Cr(VI) content of 200 μg/L. In order to support biological growth, groundwater was supplemented with milk, liquid cheese whey or a mixture of sugar and milk to achieve a COD concentration of 200 mg/L. The results demonstrate that a fully anaerobic system or an anaerobic-aerobic system dosed with simple or complex external organic carbon sources can lead to practically complete Cr(VI) reduction to Cr(III). The temperature dependency of maximum Cr(VI) removal rates can be described by the Arrhenius relationship. Total chromium removal in the biological treatment systems was not complete because a significant portion of Cr(III) remained in solution. An integrated system comprising of an anaerobic SBR followed by a sand filter achieved more than 95% total chromium removal thus resulting in average effluent total and dissolved chromium concentrations of 7 μg/L and 3 μg/L, respectively.

  6. Baffled membrane bioreactor (BMBR) for advanced wastewater treatment: easy modification of existing MBRs for efficient nutrient removal.

    PubMed

    Kimura, K; Watanabe, Y

    2005-01-01

    In this study, a novel membrane bioreactor (MBR) in which nitrification and denitrification simultaneously proceed in a single reaction chamber is proposed for advanced municipal wastewater treatment. Anoxic/aerobic environments are alternatively created in the proposed MBR by inserting baffles inside the membrane chamber. The performance of the proposed baffled membrane bioreactor (BMBR) was examined at an existing municipal wastewater treatment facility based on long-term operation. Although the procedure was simple, insertion of the baffles actually created the alternative anoxic/aerobic environments in the chamber at a constant interval and showed a great improvement in the nutrient removal. The insertion did not cause any adverse effect on membrane permeability. In this study, almost complete elimination of NH4+-N was observed while around 8 mg/L of NO(3-)-N was detected in the treated water. The modification proposed in this study can immediately be applied to most existing MBRs and is highly recommended for more efficient wastewater treatment.

  7. Full-scale demonstration of step feed concept for improving an anaerobic/anoxic/aerobic nutrient removal process.

    PubMed

    Ge, Shijian; Zhu, Yunpeng; Lu, Congcong; Wang, Shuying; Peng, Yongzhen

    2012-09-01

    A small wastewater treatment plant (WWTP) failed to meet effluent requirements of the first-A discharge standard in China, with the anaerobic/anoxic/oxic (A/A/O) process treating municipal and partial industrial wastewater. Thus an A/O step feed process (Anoxic/oxic/anoxic/oxic/anoxic/oxic) with floating plastic carriers in aerobic units was proposed to improve nutrient removal within the existing WWTP. Four main reform strategies were applied: (1) the original influent was divided into three streams which led into corresponding anoxic units; (2) floating plastic carriers were placed in the second and third oxic units; (3) nitrified liquid recycling was omitted; (4) channel shapes and sizes were adjusted between adjacent units to prevent backflow. After these modifications were implemented, the total nitrogen and phosphorus concentrations in the effluent were reduced from 20.8 to 14.2mg/L, and from 1.89 to 0.57 mg/L, respectively. Moreover, annual electricity consumption in the WWTP was reduced by 245 MWh as a result of these modifications.

  8. Effects of internal recycling time mode and hydraulic retention time on biological nitrogen and phosphorus removal in a sequencing anoxic/anaerobic membrane bioreactor process.

    PubMed

    Song, Kyung-Guen; Cho, Jinwoo; Ahn, Kyu-Hong

    2009-01-01

    This study investigated the effects of internal recycling time mode and hydraulic retention time (HRT) on nutrient removal in the sequencing anoxic/anaerobic membrane bioreactor process. Denitrification and phosphorus release were reciprocally dependent on the anoxic/anaerobic time ratio (Ax/An). As Ax/An increased, nitrogen removal rate increased but phosphorus removal rate decreased. The increasing Ax/An provided the longer denitrification period so that the organic substrate were consumed more for denitrification rather than phosphorus release in the limited condition of readily biodegradable substrate. Decreasing HRT increased both nitrogen and phosphorus removal efficiency because as HRT decreased, food-to-microorganism loading ratio increased and thus enhanced the biological capacity and activity of denitrifying bacteria. This could be verified from the observation mixed liquor suspended solids concentration and specific denitrification rate. The change of Ax/An and HRT affected phosphorus removal more than nitrogen removal due to the limitation of favourable carbon source for phosphorus accumulating organisms.

  9. Experimental and modeling study on removal of pharmaceutically active compounds in rotating biological contactors.

    PubMed

    Vasiliadou, I A; Molina, R; Martínez, F; Melero, J A

    2014-06-15

    The aim of this work was to study the biological removal of pharmaceutical compounds in rotating biological contactors (RBCs) under continuous operation. A two-stage RBC was used, providing a total surface area of 1.41 m(2). Four pharmaceuticals of different therapeutic classes; caffeine, sulfamethoxazole, ranitidine and carbamazepine, were studied. Six experimental scenarios were applied to the RBC-system by varying substrates' loadings (12-54 gCOD/d), volumetric flow rate (2-5L/d), and pharmaceuticals' concentration (20-50 μg/L). The different conditions resulted to different solid retention times (SRT: 7-21 d) in each scenario. The increase of SRT due to variations of the operating conditions seemed to have a positive effect on pharmaceuticals' removal. Likewise, a negative correlation was observed between substrates' loading and pharmaceuticals' removal. An increase of initial pharmaceuticals' concentration resulted to decrease of SRT and pharmaceuticals' removal, suggesting a toxic effect to the biofilm. The maximum removals achieved were greater than 85% for all pharmaceuticals. Finally, a mathematical model which includes biofilm growth, substrates' utilization and pharmaceuticals' elimination was developed. The model predicts the contribution of sorption and biodegradation on pharmaceuticals' elimination taking into account the diffusion of pharmaceuticals inside biofilm.

  10. Combined advanced oxidation and biological treatment processes for the removal of pesticides from aqueous solutions.

    PubMed

    Lafi, Walid K; Al-Qodah, Z

    2006-09-01

    Advanced oxidation processes were combined with biological treatment processes in this study to remove both pesticides and then the COD load from aqueous solutions. It was found that O(3) and O(3)/UV oxidation systems were able to reach 90 and 100%, removal of the pesticide Deltamethrin, respectively, in a period of 210 min. The use of O(3) combined with UV radiation enhances pesticides degradation and the residual pesticide reaches zero in the case of Deltamethrin. The combined O(3)/UV system can reduce COD up to 20% if the pH of the solution is above 4. Both pesticide degradation and COD removal in the combined O(3)/UV system follow the pseudo-first-order kinetics and the parameters of this model were evaluated. The application of the biological treatment to remove the bulk COD from different types of feed solution was investigated. More than 95% COD removal was achieved when treated wastewater by the O(3)/UV system was fed to the bioreactor. The parameters of the proposed Grau model were estimated.

  11. Removal of anaerobic soluble microbial products in a biological activated carbon reactor.

    PubMed

    Dong, Xiaojing; Zhou, Weili; He, Shengbing

    2013-09-01

    The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable. Focusing on the biodegradation of anaerobic SMP, the biological activated carbon (BAC) was introduced into the anaerobic system. The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors. The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2, i.e., BAC) functioned as a polishing step to remove SMP produced in UASB1. The results showed that 90% of the SMP could be removed before granular activated carbon was saturated. After the saturation, the SMP removal decreased to 60% on the average. Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation. A strain of SMP-degrading bacteria, which was found highly similar to Klebsiella sp., was isolated, enriched and inoculated back to the BAC reactor. When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m3 x day), the effluent from the BAC reactor could meet the discharge standard without further treatment. Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective, cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L.

  12. 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.

  13. Biological-Community Composition in Small Streams and its Relations to Habitat, Nutrients, and Land Use in Agriculturally Dominated Landscapes in Indiana and Ohio, 2004, and Implications for Assessing Nutrient Conditions in Midwest Streams

    USGS Publications Warehouse

    Caskey, Brian J.; Frey, Jeffrey W.

    2009-01-01

    The objective of this study was to relate algal-, invertebrate-, and fish-community composition to habitat, nutrients, and land-use variables in small streams in agriculturally dominated landscapes of the Midwest in Indiana and Ohio. Thirty sample locations were selected from a single ecoregion; all were small wadable streams within agriculturally dominated landscapes with similar substrate and canopy. Biological and nutrient samples were collected during stable flow conditions in August 2004. Canonical correspondence analysis was used to determine which variables most influenced each community. Total phosphorus concentrations significantly influenced the depositional-targeted habitat algal-diatom community and the richest-targeted habitat invertebrate community. Multivariate statistical analysis showed that habitat variables were more influential to the richest-targeted habitat algal-diatom and fish communities than nutrient concentrations. Although the nutrient concentrations measured during this study indicate that most streams were not eutrophic, the biological communities were dominated by eutrophic species, suggesting streams sampled were eutrophic. Consequently, it was concluded that biological relations to nutrients in agriculturally dominated landscapes are complex and habitat variables should be included in biological assessments of nutrient conditions in agriculturally dominated landscapes.

  14. Feasibility of removing surface deposits on stone using biological and chemical remediation methods.

    PubMed

    Polo, A; Cappitelli, F; Brusetti, L; Principi, P; Villa, F; Giacomucci, L; Ranalli, G; Sorlini, C

    2010-07-01

    The study was conducted on alterations found on stone artwork and integrates microbial control and a biotechnological method for the removal of undesirable chemical substances. The Demetra and Cronos sculptures are two of 12 stone statues decorating the courtyard of the Buonconsiglio Castle in Trento (Italy). An initial inspection of the statues revealed putative black crusts and highlighted the microbial contamination causing discoloration. In 2006, the Cultural Heritage Superintendence of Trento commissioned us to study and remove these chemical and biological stains. Stereomicroscopy characterised the stone of the sculptures as oolitic limestone, and infrared analyses confirmed the presence of black crusts. To remove the black crusts, we applied a remediation treatment of sulphate-reducing bacteria, which removes the chemical alteration but preserves the original stone and the patina noble. Using traditional and biomolecular methods, we studied the putative microbial contamination and confirmed the presence of biodeteriogens and chose biocide Biotin N for the removal of the agents causing the discolouration. Denaturing gradient gel electrophoresis fluorescent in situ hybridisation established that Cyanobacteria and green algae genera were responsible for the green staining whereas the black microbial contamination was due to dematiaceous fungi. After the biocide Biotin N treatment, we applied molecular methods and demonstrated that the Cyanobacteria, and most of the green algae and dematiaceous fungi, had been efficiently removed. The reported case study reveals that conservators can benefit from an integrated biotechnological approach aimed at the biocleaning of chemical alterations and the abatement of biodeteriogens.

  15. Temperature influence on biological phosphorus removal induced by aerobic/extended-idle regime.

    PubMed

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

    2014-05-01

    Previous researches have demonstrated that biological phosphorus removal (BPR) from wastewater could be driven by the aerobic/extended-idle (A/EI) regime. This study further investigated temperature effects on phosphorus removal performance in six A/EI sequencing batch reactors (SBRs) operated at temperatures ranging from 5 to 30 °C. The results showed that phosphorus removal efficiency increased with temperature increasing from 5 to 20 °C but slightly decreased when temperature continually increased to 30 °C. The highest phosphorus removal rate of 97.1 % was obtained at 20 °C. The biomass cultured at 20 °C contained more polyphosphate accumulating organisms (PAO) and less glycogen accumulating organisms (GAO) than that cultured at any other temperatures investigated. The mechanism studies revealed that temperature affected the transformations of glycogen and polyhydroxyalkanoates, and the activities of exopolyphosphatase and polyphosphate kinase activities. In addition, phosphorus removal performances of the A/EI and traditional anaerobic/oxic (A/O) SBRs were compared at 5 and 20 °C, respectively. The results showed the A/EI regime drove better phosphorus removal than the A/O regime at both 5 and 20 °C, and more PAO and less GAO abundances in the biomass might be the principal reason for the higher BPR in the A/EI SBRs as compared with the A/O SBRs.

  16. Inducing mechanism of biological phosphorus removal driven by the aerobic/extended-idle regime.

    PubMed

    Wang, Dongbo; Yang, Guojing; Li, Xiaoming; Zheng, Wei; Wu, Yan; Yang, Qi; Zeng, Guangming

    2012-11-01

    Recently, it was found that excess phosphorus (Pi) removal could be achieved in activated sludge with an aerobic/extended-idle (AEI) process. In this study, batch tests were performed to further reveal the inducing mechanism of Pi removal involved in the AEI process. Unlike the classical anaerobic/aerobic process where an anaerobic Pi release along with a significant polyhydroxyalkanoate (PHA) accumulation drives polyphosphate (poly-P) accumulating organisms (PAOs) to over-store Pi as poly-P, an idle Pi release accompanied by a low-idle PHA production, which is usually considered to be detrimental for biological Pi removal, was observed to induce some cells to effectively uptake Pi in excess of metabolic requirement in the AEI process. With the increase of idle Pi release, Pi removal efficiency linearly increased. The results also showed that a long idle period with a low level of intracellular glycogen could significantly increase Pi release contents, thus remarkably enhancing Pi removal performances. Fluorescence in situ hybridization analysis further revealed that activated sludge in the AEI process contained 37.6% of Accumulibacter (PAOs) and 28.2% of Competibacter and Defluviicoccus-related organisms (glycogen accumulating organisms). This study revealed an actually existent, yet previously unrecognized, inducing mechanism of poly-P accumulation, and this mechanism behind the AEI regime may provide a scientific basis for the development of an alternative strategy for Pi removal from wastewaters.

  17. Effect of side-stream phosphorus recovery on biological phosphorus removal performance investigated by chemical and microbial analyses in a novel BNR-IC process.

    PubMed

    Zou, H M; Lu, X W; Li, T

    2014-01-01

    The aim of this study was to assess the effect of side-stream ratio (SSR) on performance of phosphorus (P) removal and recovery in a novel process linking biological nutrients removal (BNR) and induced crystallization (IC). Results showed that P removal efficiency was significantly enhanced when given an appropriate SSR, resulting in effluent P concentrations decreasing from 0.75 to 0.39 mg/L with an increase of SSR from 0 to 35%, where a maximum of 7.19 mg/L P recovery amount was obtained at 35% of SSR. Increasing the SSR can favor the P recovery, while an excessively high SSR (more than 35%) would have a negative effect on the subsequent biological P removal in the BNR-IC system. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis showed that in total, 11 DGGE bands of highest species richness were visually detected and significant changes in microbial community structure were found, with SSR variations ranging from 0 to 55%. Moreover, an increase in SSR can cause an increase in microbial community biodiversity; where microbial populations correspond to the 11 bands, they were generally classified into five different phyla or classes (Beta-, Gamma-, and Deltaproteobacteria, as well as Clostridia and Flavobacteria) based on the evolutionary tree analysis.

  18. Review on fate and mechanism of removal of pharmaceutical pollutants from wastewater using biological approach.

    PubMed

    Tiwari, Bhagyashree; Sellamuthu, Balasubramanian; Ouarda, Yassine; Drogui, Patrick; Tyagi, Rajeshwar D; Buelna, Gerardo

    2017-01-01

    Due to research advancement and discoveries in the field of medical science, maintains and provides better human health and safer life, which lead to high demand for production of pharmaceutical compounds with a concomitant increase in population. These pharmaceutical (biologically active) compounds were not fully metabolized by the body and excreted out in wastewater. This micro-pollutant remains unchanged during wastewater treatment plant operation and enters into the receiving environment via the discharge of treated water. Persistence of pharmaceutical compounds in both surface and ground waters becomes a major concern due to their potential eco-toxicity. Pharmaceuticals (emerging micro-pollutants) deteriorate the water quality and impart a toxic effect on living organisms. Therefore, from last two decades, plenty of studies were conducted on the occurrence, impact, and removal of pharmaceutical residues from the environment. This review provides an overview on the fate and removal of pharmaceutical compounds via biological treatment process.

  19. The ability of biologically based wastewater treatment systems to remove emerging organic contaminants--a review.

    PubMed

    Garcia-Rodríguez, Aida; Matamoros, Víctor; Fontàs, Clàudia; Salvadó, Victòria

    2014-10-01

    Biologically based wastewater treatment systems are considered a sustainable, cost-effective alternative to conventional wastewater treatment systems. These systems have been used and studied for the treatment of urban sewage from small communities, and recently, it has been reported that they can also effectively remove emerging organic contaminants (EOCs). EOCs are a new group of unregulated contaminants which include pharmaceutical and personal care products, some pesticides, veterinary products, and industrial compounds among others that are thought to have long-term adverse effects on human health and ecosystems. This review is focused on reporting the ability of biologically based wastewater treatment systems to remove EOCs and the main elimination mechanisms and degradation processes (i.e., biodegradation, photodegradation, phytoremediation, and sorption) taking place in constructed wetlands, ponds, and Daphnia and fungal reactors.

  20. PAH removal from spiked municipal wastewater sewage sludge using biological, chemical and electrochemical treatments.

    PubMed

    Zheng, Xue-Jing; Blais, Jean-François; Mercier, Guy; Bergeron, Mario; Drogui, Patrick

    2007-06-01

    Polycyclic aromatic hydrocarbons (PAHs) have been widely studied due to their presence in all the environmental media and toxicity to life. These molecules are strongly adsorbed on the particulate matters of soils, sludges or sediments because of their strong hydrophobicity which makes them less bioavailability, thus limiting their bioremediation. Different sludge treatment processes were tested to evaluate their performances for PAH removal from sludge prealably doped with 11 PAHs (5.5mg each PAH kg(-1) of dry matter (DM)): two biological processes (mesophilic aerobic digestion (MAD) and simultaneous sewage sludge digestion and metal leaching (METIX-BS)) were tested to evaluate PAH biodegradation in sewage sludge. In parallel, two chemical processes (quite similar Fenton processes: chemical metal leaching (METIX-AC) and chemical stabilization (STABIOX)) and one electrochemical process (electrochemical stabilization (ELECSTAB)) were tested to measure PAH removal by these oxidative processes. Moreover, PAH solubilisation from sludge by addition of a nonionic surfactant Tween 80 (Tw80) was also tested. The best yields of PAH removal were obtained by MAD and METIX-BS with more than 95% 3-ring PAH removal after a 21-day treatment period. Tw80 addition during MAD treatment increased 4-ring PAHs removal rate. In addition, more than 45% of 3-ring PAHs were removed from sludge by METIX-AC and during ELECSTAB process were quiet good with approximately 62% of 3-ring PAHs removal. However, little weaker removal of 3-ring PAHs (<35%) by STABIOX. None of the tested processes were efficient for the elimination of high molecular weight (> or = 5-ring) PAHs from sludge.

  1. [Mechanism of nitrogen removal by partial nitrification-denitrification biological filter].

    PubMed

    Sun, Ying-Xue; Xu, Dong; Tian, Yuan; Li, Yan-Fei

    2012-10-01

    The controlling factors for nitrite accumulation in partial nitrification and mechanism of nitrogen removal from the secondary effluent of wastewater treatment plant by partial nitrification-denitrification biological filter were investigated. The results showed that nitrite accumulated with increasing of pH value in the influent under the condition of temperature was (30 +/- 1) degrees C. The nitrite accumulation achieved to the highest at a pH value of 8.5 in this batch experiments. In addition, the nitrite accumulation presented increasing tendency through the up-flow nitrifying biological filter, which can be adjusted by the changes of pH and DO through the filter. The removal efficiency of NH4+ -N was over 90% by the partial nitrification-denitrification biological filter. Meanwhile, carbon sources were supplied for the denitrifying bacteria to accomplish denitrification process. Under the condition of COD/TN at a value of 3.0, the concentration of TN in the effluent of denitrifying biofilter was 8-9 mg x L(-1) and the removal efficiency achieved 79% - 81%, stably.

  2. [Effect of magnesium ion content on the biological phosphorus removal system in SBR].

    PubMed

    Li, Xing; Gao, Da-Wen; Liu, Lin

    2011-07-01

    This study investigated the effect of magnesium iron content on the enhanced biological phosphorus removal system, which performed differently at magnesium content of 0 mg/L, 8 mg/L and 24 mg/L (R1-R3). The results indicated appropriate Mg addition could enrich phosphorus accumulating organisms and keep stable running. During the steady state period, phosphorus removal rate declined to below 50% gradually, moreover, the system tended to deteriorate with the shortage of magnesium in R1. However, the system with appropriate magnesium kept the higher phosphorus removal rate (more than 90%). The statistical analysis of the experimental data also showed a strong correlation between Mg and phosphorus concentrations in R2 and R3, the ratios of Mg and P were 0.29-0.59 and 0.25-0.54 in two reactors respectively. In the anaerobic phase of EBPR, the magnesium content, the absolute value of ORP and the phosphates release had a correlation. Meanwhile, magnesium was released together with phosphates in the anaerobic phase, and that would uptake under aerobic conditions. Thus it was obvious that magnesium played a key role on the biological phosphorus removal system.

  3. Enhancing combined biological nitrogen and phosphorus removal from wastewater by applying mechanically disintegrated excess sludge.

    PubMed

    Zubrowska-Sudol, Monika; Walczak, Justyna

    2015-06-01

    The goal of the study was to evaluate the possibility of applying disintegrated excess sludge as a source of organic carbon to enhance biological nitrogen and phosphorus removal. The experiment, performed in a sequencing batch reactor, consisted of two two-month series, without and with applying mechanically disintegrated excess sludge, respectively. The effects on carbon, nitrogen and phosphorus removal were observed. It was shown that the method allows enhancement of combined nitrogen and phosphorus removal. After using disintegrated sludge, denitrification effectiveness increased from 49.2 ± 6.8% to 76.2 ± 2.3%, which resulted in a decline in the NOx-N concentration in the effluent from the SBR by an average of 21.4 mg NOx-N/L. Effectiveness of biological phosphorus removal increased from 28.1 ± 11.3% to 96.2 ± 2.5%, thus resulting in a drop in the [Formula: see text] concentration in the effluent by, on average, 6.05 mg PO4(3-)-P/L. The application of disintegrated sludge did not deteriorate effluent quality in terms of COD and NH4(+)-N. The concentration of NH4(+)-N in both series averaged 0.16 ± 0.11 mg NH4(+)-N/L, and the concentration of COD was 15.36 ± 3.54 mg O2/L.

  4. Effects of Litter Removal and Addition on the Nutrient Mineralization Dynamics in Hyperseasonal Tropical Savannas of the Brazilian Pantanal

    NASA Astrophysics Data System (ADS)

    Hentz, C. S.; Pinto-Jr, O. B.; Vourlitis, G. L.

    2015-12-01

    The tropical savanna of Brazil (cerrado) is extremely species diverse and it encompasses many different physiognomic features, which are influenced by rainfall, fire, and soil nutrient availability. Plant litter decomposition recycles nutrients to the soil, and in turn, assists plant growth. However the rate at which these nutrients become available to the soil is poorly understood. Thus, a six month field experiment that encompassed the wet and dry seasons was conducted to assess how different quantities of litter inputs affect nutrient (P, N, C, K, Ca, and Mg) availability. It was hypothesized that nutrient mineralization would be significantly influenced by manipulation of the surface litter and that there would be a positive correlation between soil moisture and nutrient mineralization. Initial results indicate that there were significant differences in mineralization over time for all nutrients, except P, supporting our hypothesis of changes in mineralization with soil moisture. However, there were no significant differences between litter treatments and net mineralization rates for all the nutrients tested. Our results indicate that litterpool size has little effect on short-term nutrient mineralization dynamics.

  5. LANDSCAPE INDICATORS FOR PESTICIDES, NUTRIENTS, EMERGING CONTAMINANTS, AND AQUATIC BIOLOGY IN MIDWESTERN CORN BELT STREAMS

    EPA Science Inventory

    This study is part of a long-term cooperative national research project among the US EPA and the USGS to collect comparable water-quality data from small streams and to develop regional predicitive models that use landscape characteristics to estimate pesticide and nutrient conce...

  6. Ocean nutrients

    NASA Astrophysics Data System (ADS)

    Boyd, Philip W.; Hurd, Catriona L.

    Nutrients provide the chemical life-support system for phytoplankton in the ocean. Together with the carbon fixed during photosynthesis, nutrients provide the other elements, such as N and P, needed to synthesize macromolecules to build cellular constituents such as ribosomes. The makeup of these various biochemicals, such as proteins, pigments, and nucleic acids, together determine the elemental stoichiometry of an individual phytoplankton cell. The stoichiometry of different phytoplankton species or groups will vary depending on the proportions of distinct cellular machinery, such as for growth or resource acquisition, they require for their life strategies. The uptake of nutrients by phytoplankton helps to set the primary productivity, and drives the biological pump, of the global ocean. In the case of nitrogen, the supply of nutrients is categorized as either new or regenerated. The supply of new nitrogen, such as nitrate upwelled from the ocean' interior or biological nitrogen fixation, is equal to the vertical export of particular organic matter from the upper ocean on a timescale of years. Nutrients such as silica can also play a structural role in some phytoplankton groups, such as diatoms, where they are used to synthesize a siliceous frustule that offers some mechanical protection from grazers. In this chapter, we also explore nutrient uptake kinetics, patterns in nutrient distributions in space and time, the biogeochemical cycle of nitrogen, the atmospheric supply of nutrients, departures from the Redfield ratio, and whether nutrient distributions and cycling will be altered in the future

  7. Two-phase photoperiodic cultivation of algal-bacterial consortia for high biomass production and efficient nutrient removal from municipal wastewater.

    PubMed

    Lee, Chang Soo; Oh, Hyung-Seok; Oh, Hee-Mock; Kim, Hee-Sik; Ahn, Chi-Yong

    2016-01-01

    This study investigated the photoperiodic effects on the biomass production and nutrient removal in the algal-bacterial wastewater treatment, under the following three conditions: (1) a natural 12h:12h LD cycle, (2) a dark-elongated 12h:60h LD cycle, and (3) a two-phase photoperiodic 12h:60h LD, followed by 12h:12h LD cycles. The two-phase photoperiodic operation showed the highest dry cell weight and lipid productivity (282.6mgL(-1)day(-1), 71.4mgL(-1)day(-1)) and most efficient nutrient removals (92.3% COD, 95.8% TN, 98.1% TP). The genetic markers and sequencing analyses indicated rapid increments of bacteria, subsequent growths of Scenedesmus, and stabilized population balances between algae and bacteria. In addition, the two-phase photoperiod provided a higher potential for the algal-bacterial consortia to utilize various organic carbon substrates.

  8. Biological phosphorus removal from a phosphorus-rich dairy processing wastewater.

    PubMed

    Bickers, P O; Bhamidimarri, R; Shepherd, J; Russell, J

    2003-01-01

    Dairy industry processing wastewaters consist mainly of dilutions of milk, milk products and cleaning solutions and, depending on the processes used, may be rich in phosphorus. In New Zealand and internationally, chemical removal of phosphorus is typically the phosphorus removal method of choice from dairy processing wastewaters. The enhanced biological phosphorus removal (EBPR) process was investigated in this study as an alternative phosphorus removal option using a continuous activated sludge system. A synthetic dairy processing wastewater was firstly subjected to fermentation in an anaerobic reactor (HRT = 12 hrs, pH = 6.5, temperature = 35 degrees C) resulting in a fermented wastewater with an average volatile fatty acid (VFA) concentration of 1055 mg COD/L. The activated sludge reactor was operated in an AO configuration with an HRT of 2.5 days and an SRT of 15 days. Stable EBPR was exhibited with 42 mg P/L removed, resulting in a final sludge phosphorus content of 4.9% mg P/mg TSS. In the anaerobic zone (HRT = 2.85 hrs) the sludge had a phosphorus content of 3.16% mg P/mg TSS and a poly-beta-hydroxyalkanoate (PHA) concentration of 86 mg COD/g TS.

  9. The oxidation of As(III) in groundwater using biological manganese removal filtration columns.

    PubMed

    Yang, Hong; Sun, Wenyong; Ge, Huoqing; Yao, Renda

    2015-01-01

    Arsenic is known as a toxic element to humans, and has been reported to co-exist with iron and manganese in groundwater worldwide. The typical method for arsenic removal from groundwater is to oxidize trivalent (As(III)) to pentavalent (As(V)) followed by the As(V) removal. This study aims to evaluate the oxidization efficiency of As(III) in a mature biological manganese (Mn(2+)) removal filtration system with different elevated influent As(III) concentrations. The effects of influent Mn(2+) concentrations, influent As(III) concentrations, filtration rates and dissolved oxygen (DO) levels on the efficiency of As(III) oxidation were assessed. The results showed that As(III) oxidation can be simultaneously achieved with removing Mn(2+) in the filtration system. The oxidation efficiency was not impacted by increasing the influent As(III) concentration up to nearly 2500 µg L(-1), but the filtration rate was limited at 11 m h(-1) for maintaining the effluent As(III) concentration below 10 µg L(-1). The oxidation process followed first-order kinetics with the constant reaching 0.56-0.61 min(-1). The As(III) oxidation process was most likely to be mediated by the bacterial community initially developed for Mn(2+) removal in the filtration system, which performed the catalytic oxidation for As(III).

  10. Effects of ZnO nanoparticles on wastewater biological nitrogen and phosphorus removal.

    PubMed

    Zheng, Xiong; Wu, Rui; Chen, Yinguang

    2011-04-01

    With the increasing utilization of nanomaterials, zinc oxide nanoparticles (ZnO NPs) have been reported to induce adverse effects on human health and aquatic organisms. However, the potential impacts of ZnO NPs on wastewater nitrogen and phosphorus removal with an activated sludge process are unknown. In this paper, short-term exposure experiments were conducted to determine whether ZnO NPs caused adverse impacts on biological nitrogen and phosphorus removal in the unacclimated anaerobic-low dissolved oxygen sequencing batch reactor. Compared with the absence of ZnO NPs, the presence of 10 and 50 mg/L of ZnO NPs decreased total nitrogen removal efficiencies from 81.5% to 75.6% and 70.8%, respectively. The corresponding effluent phosphorus concentrations increased from nondetectable to 10.3 and 16.5 mg/L, respectively, which were higher than the influent phosphorus (9.8 mg/L), suggesting that higher concentration of ZnO NPs induced the loss of normal phosphorus removal. It was found that the inhibition of nitrogen and phosphorus removal induced by higher concentrations of ZnO NPs was due to the release of zinc ions from ZnO NPs dissolution and increase of reactive oxygen species (ROS) production, which caused inhibitory effect on polyphosphate-accumulating organisms and decreased nitrate reductase, exopolyphosphatase, and polyphosphate kinase activities.

  11. Influence of SiO2 and graphene oxide nanoparticles on efficiency of biological removal process.

    PubMed

    Esmaeili-Faraj, Seyyed Hamid; Nasr Esfahany, Mohsen

    2017-01-19

    The effects of the presence of synthesized silica (SS) and exfoliated graphene oxide (EGO) on the removal of sulfide ion with activated sludge (AS) are experimentally investigated. The maximum removal efficiency of sulfide ion for AS without nanoparticles, and the samples with SS and EGO nanoparticles were 81%, 88% and 79%, respectively. Moreover, the maximum elimination capacity (ECmax) for the bioreactor with SS-nanoparticles is 7542 mg/L s, while the ECmax of AS and EGO samples were 7075 and 6625 mg/L s, respectively. Two filamentous microbial strains as Gram-negative and Gram-positive bacteria are discerned that removed sulfide ion in the presence of nanoparticles. The measurement of mixture liquor volatile suspended solid that indicates the biomass growth rate during the test shows that the bioreactor containing SS-nanoparticles has more biomass content than the other samples. Our findings indicate that SS-nanoparticles with 0.1% wt. concentration in the bioreactor have no negative effects on the efficiency of the biological removal of sulfide and the presence of SS-nanoparticles even enhances the performance of the bioreactor. On the other side, a bioreactor with EGO nanosheets, as highly antibacterial nanoparticles, with 0.02% wt. concentration significantly influences the microbial growth and reduces sulfide removal efficiency.

  12. Comparison of quartz sand, anthracite, shale and biological ceramsite for adsorptive removal of phosphorus from aqueous solution.

    PubMed

    Jiang, Cheng; Jia, Liyue; Zhang, Bo; He, Yiliang; Kirumba, George

    2014-02-01

    The choice of substrates with high phosphorus adsorption capacity is vital for sustainable phosphorus removal from waste water in constructed wetlands. In this study, four substrates were used: quartz sand, anthracite, shale and biological ceramsite. These substrate samples were characterized by Xray diffractometry and scanning electron microscopy studies for their mineral components (chemical components) and surface characteristics. The dynamic experimental results revealed the following ranking order for total phosphorus (TP) removal efficiency: anthracite > biological ceramsite > shale > quartz sand. The adsorptive removal capacities for TP using anthracite, biological ceramsite, shale and quartz sand were 85.87, 81.44, 59.65, and 55.98 mg/kg, respectively. Phosphorus desorption was also studied to analyze the substrates' adsorption efficiency in wastewater treatment as well as the substrates' ability to be reused for treatment. It was noted that the removal performance for the different forms of phosphorus was dependent on the nature of the substrate and the adsorption mechanism. A comparative analysis showed that the removal of particulate phosphorus was much easier using shale. Whereas anthracite had the highest soluble reactive phosphorus (SRP) adsorptive capacity, biological ceramsite had the highest dissolved organic phosphorus (DOP) removal capacity. Phosphorus removal by shale and biological ceramsite was mainly through chemical adsorption, precipitation or biological adsorption. On the other hand, phosphorus removal through physical adsorption (electrostatic attraction or ion exchange) was dominant in anthracite and quartz sand.

  13. Mechanisms of manganese removal from wastewaters in constructed wetlands comprising water hyacinth (Eichhornia crassipes (Mart.) Solms) grown under different nutrient conditions.

    PubMed

    Kularatne, Ranil K A; Kasturiarachchi, Jagath C; Manatunge, Jagath M A; Wijeyekoon, Suren L J

    2009-02-01

    This article discusses key mechanisms involved in removing 1 mg/L Mn from synthetic wastewaters in constructed wetlands comprising water hyacinth (Eichhornia crassipes (Mart.) Solms) grown under different nutrient levels of 1-fold (28 mg/L and 7.7 mg/L of total nitrogen and total phosphorus, respectively), 2-fold, 1/4-fold, and 1/8-fold. A mass balance was carried out to evaluate the key removal mechanisms. Phytoremediation mainly due to phytoextraction substantially contributed to manganese removal. However, chemical precipitation was absent, suggesting that manganese has a higher solubility in the given average pH (6.2 to 7.1) conditions in constructed wetlands. Bacterial mediated immobilization mechanisms also did not contribute to manganese removal. Sediments constituted a minor sink to manganese, implying that manganese has a poor adsorption potential. Constructed wetlands comprising water hyacinth are effective at removing manganese from wastewaters despite the fact that the plants are grown under higher or lower nutrient conditions.

  14. Effect of earthworm loads on organic matter and nutrient removal efficiencies in synthetic domestic wastewater, and on bacterial community structure and diversity in vermifiltration.

    PubMed

    Wang, L M; Luo, X Z; Zhang, Y M; Lian, J J; Gao, Y X; Zheng, Z

    2013-01-01

    In this paper, we studied the effect of earthworm loads on the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen, and total phosphorus from synthetic domestic sewage and on the bacterial community structure and diversity of substrates in earthworm packing beds. The different vermifiltrations (VFs), including the control, are successful in removing both organic matter (OM) and nutrients. The removal rate of NH3-N at 12.5 g of earthworm/L of soil VF is higher compared with that at 0 and 4.5 earthworm load VFs. The highest Shannon index, in the earthworm packing bed, occurred at 16.5 earthworm load VF. Furthermore, the COD removal rate is significantly correlated with the Shannon index, which reveals that OM removal for synthetic domestic sewage treatment at VF might be more dependent on bacterial diversity at the earthworm packing bed. The band distributions and diversities of the bacterial community for samples from different earthworm loads in VFs suggest that the bacterial community structure was only affected within the earthworm packing bed when the earthworm load reached a certain level. The present study adds to the current understanding of OM and nutrient degradation processes in VF domestic wastewater treatment.

  15. 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.

  16. 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

  17. 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.

  18. Vascular plant removal effects on biological N fixation vary across a boreal forest island gradient.

    PubMed

    Gundale, Michael J; Wardle, David A; Nilsson, Marie-Charlotte

    2010-06-01

    There is currently much interest in understanding how biodiversity loss affects the functioning of ecosystems, but few studies have evaluated how ecosystem processes change in response to one another following biodiversity loss. We focused on a well-described gradient of 30 forested lake islands in northern Sweden, where island size determines the occurrence of lightning-ignited wildfire, which in turn determines successional stage, plant species composition, and productivity. We investigated the effect of biodiversity loss on biological nitrogen fixation by feathermosses through an experiment consisting of factorial removals of three understory shrub species (Vaccinium myrtillis, Vaccinium vitis-idaea, and Empetrum hermaphroditum) and two plant functional groups (shrubs and tree roots). We tested the hypothesis that, following vascular plant species loss, N fixation rates would be impaired by changes in pools or processes that increase extractable soil N, because changes in the supply rate of N to feathermosses should influence their demand for newly fixed N. Further, we hypothesized that the effects of removals on N fixation would depend on environmental context (i.e., island size), because it has been previously demonstrated that the effect of vascular plant species removal on N recycling pools and processes was strongest on productive islands. The data demonstrated that removal of two shrub species (V. vitis-idaea and E. hermaphroditum) negatively aflected the N fixation of Hylocomium splendens, but positively affected Pleurozium schreberi, resulting in unchanged areal N fixation rates. In the functional removal experiment, tree root removal resulted in a significant negative effect on N fixation. The effects of shrub and root removals on N fixation occurred only on small islands and thus were context dependent. This pattern did not correspond to the effect of shrub and root removal treatments on N-recycling pools or processes, which only occurred in response

  19. Effect of drinking water treatment process parameters on biological removal of manganese from surface water.

    PubMed

    Hoyland, Victoria W; Knocke, William R; Falkinham, Joseph O; Pruden, Amy; Singh, Gargi

    2014-12-01

    Soluble manganese (Mn) presents a significant treatment challenge to many water utilities, causing aesthetic and operational concerns. While application of free chlorine to oxidize Mn prior to filtration can be effective, this is not feasible for surface water treatment plants using ozonation followed by biofiltration because it inhibits biological removal of organics. Manganese-oxidizing bacteria (MOB) readily oxidize Mn in groundwater treatment applications, which normally involve pH > 7.0. The purpose of this study was to evaluate the potential for biological Mn removal at the lower pH conditions (6.2-6.3) often employed in enhanced coagulation to optimize organics removal. Four laboratory-scale biofilters were operated over a pH range of 6.3-7.3. The biofilters were able to oxidize Mn at a pH as low as pH 6.3 with greater than 98% Mn removal. Removal of simulated organic ozonation by-products was also greater than 90% in all columns. Stress studies indicated that well-acclimated MOB can withstand variations in Mn concentration (e.g., 0.1-0.2 mg/L), hydraulic loading rate (e.g., 2-4 gpm/ft(2); 1.36 × 10(-3)-2.72 × 10(-3) m/s), and temperature (e.g., 7-22 °C) typically found at surface water treatment plants at least for relatively short (1-2 days) periods of time.

  20. Interaction between common antibiotics and a Shewanella strain isolated from an enhanced biological phosphorus removal activated sludge system.

    PubMed

    Liu, Hang; Yang, Yongkui; Ge, Yanhui; Zhao, Lin; Long, Sha; Zhang, Ruochun

    2016-12-01

    With increasing production and consumption, more antibiotics are discharged into wastewater treatment plants and generally cannot be sufficiently removed. Because of the complexities of biological treatment processes, the fates of antibiotics and their effects on microorganisms, particularly those involved in the phosphorus removal system, are still unclear. Here, a Shewanella strain was isolated from an enhanced biological phosphorus removal (EBPR) system and was found to have the ability to remove phosphorus (P) and chemical oxygen demand (CODcr). Antibiotics affected the Shewanella strain through metabolism of the three main intracellular polymers, altering the ability of the strain to remove P and CODcr. These effects varied with the structure and concentration of the antibiotics. The Shewanella strain removed cefalexin and amoxicillin by degradation or adsorption, producing 2-hydroxy-3-phenyl pyrazine from cefalexin. This study enabled the recognition of the effect and removal of antibiotics during wastewater treatment.

  1. Environmental assessment of nutrient recycling from biological pig slurry treatment--impact of fertilizer substitution and field emissions.

    PubMed

    Brockmann, Doris; Hanhoun, Mary; Négri, Ophélie; Hélias, Arnaud

    2014-07-01

    Pig slurry treatment is an important means in reducing nitrogen loads applied to farmland. Solid phase separation prior to biological treatment further allows for recovering phosphorus with the solid phase. The organic residues from the pig slurry treatment can be applied as organic fertilizers to farmland replacing mineral fertilizers. The environmental impacts of nutrient recycling from aerobic, biological pig slurry treatment were evaluated applying the life cycle assessment (LCA) methodology. LCA results revealed that direct field emissions from organic fertilizer application and the amount of avoided mineral fertilizers dominated the environmental impacts. A modified plant available nitrogen calculation (PAN) was introduced taking into account calculated nitrogen emissions from organic fertilizer application. Additionally, an equation for calculating the quantity of avoided mineral fertilizers based on the modified PAN calculation was proposed, which accounted for nitrogen emissions from mineral fertilizer application.

  2. Removal of stigmasterol from Kraft mill effluent by aerobic biological treatment with steroidal metabolite detection.

    PubMed

    Chamorro, Soledad; Vergara, Juan P; Jarpa, Mayra; Hernandez, Victor; Becerra, Jose; Vidal, Gladys

    2016-10-14

    Stigmasterol is a phytosterol contained in Kraft mill effluent that is able to increase over 100% after aerobic biological treatment. This compound can act as an endocrine disrupter as its structure is similar to that of cholesterol. The aim of this study was to evaluate the removal of stigmasterol from Kraft mill effluents treated by a moving bed biofilm reactor (MBBR) with steroidal metabolite detection. The MBBR was operated for 145 days, with a hydraulic retention time of 2 days. Stigmasterol and steroidal metabolites were detected by gas chromatography with a flame ionization detector during MBBR operation. The results show that the MBBR removed 87.4% of biological oxygen demand (BOD5), 61.5% of chemical oxygen demand (COD), 24.5% of phenol and 31.5% of lignin, expressed in average values. The MBBR system successfully removed 100% of the stigmasterol contained in the influent (33 µg L(-1)) after 5 weeks of operation. In that case, the organic load rate was 0.343 kg COD m(-3) d(-1). Furthermore, different steroidal compounds (e.g., testosterone propionate, stigmast-4-en-3-one, 5α-pregnan-12-one-20α-hydroxy, 5α-pregnane-3,11,20-trione and 3α-hydroxy-5α-androstane-11,17-dione were detected in the Kraft mill effluent as potential products of phytosterol biotransformation.

  3. Performance of a constructed wetland in Grand Marais, Manitoba, Canada: Removal of nutrients, pharmaceuticals, and antibiotic resistance genes from municipal wastewater

    PubMed Central

    2013-01-01

    Background The discharge of complex mixtures of nutrients, organic micropollutants, and antibiotic resistance genes from treated municipal wastewater into freshwater systems are global concerns for human health and aquatic organisms. Antibiotic resistance genes (ARGs) are genes that have the ability to impart resistance to antibiotics and reduce the efficacy of antibiotics in the systems in which they are found. In the rural community of Grand Marais, Manitoba, Canada, wastewater is treated passively in a sewage lagoon prior to passage through a treatment wetland and subsequent release into surface waters. Using this facility as a model system for the Canadian Prairies, the two aims of this study were to assess: (a) the presence of nutrients, micropollutants (i.e., pesticides, pharmaceuticals), and ARGs in lagoon outputs, and (b) their potential removal by the treatment wetland prior to release to surface waters in 2012. Results As expected, concentrations of nitrogen and phosphorus species were greatest in the lagoon and declined with movement through the wetland treatment system. Pharmaceutical and agricultural chemicals were detected at concentrations in the ng/L range. Concentrations of these compounds spiked downstream of the lagoon following discharge and attenuation was observed as the effluent migrated through the wetland system. Hazard quotients calculated for micropollutants of interest indicated minimal toxicological risk to aquatic biota, and results suggest that the wetland attenuated atrazine and carbamazepine significantly. There was no significant targeted removal of ARGs in the wetland and our data suggest that the bacterial population in this system may have genes imparting antibiotic resistance. Conclusions The results of this study indicate that while the treatment wetland may effectively attenuate excess nutrients and remove some micropollutants and bacteria, it does not specifically target ARGs for removal. Additional studies would be

  4. Physical-biological coupling induced aggregation mechanism for the formation of high biomass red tides in low nutrient waters.

    PubMed

    Lai, Zhigang; Yin, Kedong

    2014-01-01

    Port Shelter is a semi-enclosed bay in northeast Hong Kong where high biomass red tides are observed to occur frequently in narrow bands along the local bathymetric isobars. Previous study showed that nutrients in the Bay are not high enough to support high biomass red tides. The hypothesis is that physical aggregation and vertical migration of dinoflagellates appear to be the driving mechanism to promote the formation of red tides in this area. To test this hypothesis, we used a high-resolution estuarine circulation model to simulate the near-shore water dynamics based on in situ measured temperature/salinity profiles, winds and tidal constitutes taken from a well-validated regional tidal model. The model results demonstrated that water convergence occurs in a narrow band along the west shore of Port Shelter under a combined effect of stratified tidal current and easterly or northeasterly wind. Using particles as dinoflagellate cells and giving diel vertical migration, the model results showed that the particles aggregate along the convergent zone. By tracking particles in the model predicted current field, we estimated that the physical-biological coupled processes induced aggregation of the particles could cause 20-45 times enhanced cell density in the convergent zone. This indicated that a high cell density red tide under these processes could be initialized without very high nutrients concentrations. This may explain why Port Shelter, a nutrient-poor Bay, is the hot spot for high biomass red tides in Hong Kong in the past 25 years. Our study explains why red tide occurrences are episodic events and shows the importance of taking the physical-biological aggregation mechanism into consideration in the projection of red tides for coastal management.

  5. Enrichment and immobilization of sulfide removal microbiota applied for environmental biological remediation of aquaculture area.

    PubMed

    Zhao, Yang-Guo; Zheng, Yu; Tian, Weijun; Bai, Jie; Feng, Gong; Guo, Liang; Gao, Mengchun

    2016-07-01

    To remove sulfide in the deteriorating aquaculture sediment and water, sulfide-oxidizing microbiota was enriched from Jiaozhou Bay, China, by using sulfide-rich medium. Composition and structure of microbial communities in the enrichments were investigated by 16S rDNA molecular biotechniques. Results showed that microbial community structure continuously shifted and the abundance of sulfate reducing bacteria, i.e., Desulfobacterium, Desulfococcus and Desulfobacca apparently declined. Several halophile genera, Vibrio, Marinobacter, Pseudomonas, Prochlorococcus, Pediococcus and Thiobacillus predominated finally in the microbiota. The enriched microbiota was capable of removing a maximum of 1000 mg/L sulfide within 12 h with 10% inoculum at pH 7.0, 20-30 °C. After immobilized, the microbiota presented excellent resistance to impact and could completely remove 600 mg/L sulfide in 12 h. Moreover, the immobilized microbiota recovered well even recycled for five times. In conclusion, the immobilized sulfide-removing microbiota showed a quite promising application for biological restoring of sulfide-rich aquaculture environment.

  6. Biologically active carbon filtration for haloacetic acid removal from swimming pool water.

    PubMed

    Tang, Hao L; Xie, Yuefeng F

    2016-01-15

    A biologically activate carbon (BAC) filter was continuously operated on site for the treatment of haloacetic acids (HAAs) in an outdoor swimming pool at an average empty bed contact time (EBCT) of 5.8 min. Results showed that BAC filtration was a viable technology for direct removal of HAAs from the pool water with a nominal efficiency of 57.7% by the filter while the chlorine residuals were 1.71 ± 0.90 mg/L during the study. THMs and TOC were not removed and thus were not considered as indicators of the effectiveness of BAC filtration. Increased EBCT in the range of 4.5 and 6.4 min led to improved HAA removal performance, which could be best fit by a logarithmic regression model. BAC filtration also affected the HAA speciation by removing more dichloroacetic acid (DCAA) than trichloroacetic acid (TCAA), resulting in a lower ratio of DCAA/TCAA in the filtered effluent. However, the observation of an overall constant ratio could be attributable to a complex formation and degradation mechanism occurring in swimming pools.

  7. Biological phosphorus removal in sequencing batch reactor with single-stage oxic process.

    PubMed

    Wang, Dong-Bo; Li, Xiao-Ming; Yang, Qi; Zeng, Guang-Ming; Liao, De-Xiang; Zhang, Jie

    2008-09-01

    The performance of biological phosphorus removal (BPR) in a sequencing batch reactor (SBR) with single-stage oxic process was investigated using simulated municipal wastewater. The experimental results showed that BPR could be achieved in a SBR without anaerobic phase, which was conventionally considered as a key phase for BPR. Phosphorus (P) concentration 0.22-1.79 mg L(-1) in effluent can be obtained after 4h aeration when P concentration in influent was about 15-20 mg L(-1), the dissolved oxygen (DO) was controlled at 3+/-0.2 mg L(-1) during aerobic phase and pH was maintained 7+/-0.1, which indicated the efficiencies of P removal were achieved 90% above. Experimental results also showed that P was mainly stored in the form of intracellular storage of polyphosphate (poly-P), and about 207.235 mg phosphates have been removed by the discharge of rich-phosphorus sludge for each SBR cycle. However, the energy storage poly-beta-hydroxyalkanoates (PHA) was almost kept constant at a low level (5-6 mg L(-1)) during the process. Those results showed that phosphate could be transformed to poly-P with single-stage oxic process without PHA accumulation, and BPR could be realized in net phosphate removal.

  8. A combined biological removal of Cd(2+) from aqueous solutions using Phanerochaete chrysosporium and rice straw.

    PubMed

    Zhao, Meihua; Zhang, Chaosheng; Zeng, Guangming; Cheng, Min; Liu, Yang

    2016-08-01

    The removal of Cd(2+) from aqueous solutions by agricultural residues rice straw combined with white rot fungus Phanerochaete chrysosporium (P. chrysosporium) was investigated. The results showed that over 99% of the total Cd(2+) (initial concentration of 150mgL(-1)) was removed at the optimal operating conditions (pH 5.0 at 35°C). We also found that P. chrysosporium could survive under Cd(2+) stress even with an initial Cd(2+) concentration of 250mgL(-1). But when Cd(2+) concentration increased to 250mgL(-1), fungus growth and reproduction were remarkably restrained, and as a result, Cd(2+) removal dropped to 59.2%. It was observed that the fungus biomass and activities of ligninolytic enzymes decreased at some degree under high concentration of Cd(2+) (above 100mgL(-1)). Also, we found that a moderate Cd(2+) stress (below 150mgL(-1)) could stimulate P. chrysosporium's production of the heavy metals chelator - oxalate. This study will provide useful information for the application of biological removal of heavy metal irons from wastewater.

  9. A comparative study of the bacterial community in denitrifying and traditional enhanced biological phosphorus removal processes.

    PubMed

    Lv, Xiao-Mei; Shao, Ming-Fei; Li, Chao-Lin; Li, Ji; Gao, Xin-Lei; Sun, Fei-Yun

    2014-09-17

    Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphorus removal rates being 87.9% and 89.0% respectively. The community structures in denitrifying and traditional EBPR processes were evaluated by high-throughput sequencing of the PCR-amplified partial 16S rRNA genes from each sludge. The results obtained showed that the bacterial community was more diverse in A-O sludge than in A-A sludge. Taxonomy and β-diversity analyses indicated that a significant shift occurred in the dominant microbial community in A-A sludge compared with the seed sludge during the whole acclimation phase, while a slight fluctuation was observed in the abundance of the major taxonomies in A-O sludge. One Dechloromonas-related OTU outside the 4 known Candidatus "Accumulibacter" clades was detected as the main OTU in A-A sludge at the stationary operation, while Candidatus "Accumulibacter" dominated in A-O sludge.

  10. Impact of butyrate on microbial selection in enhanced biological phosphorus removal systems.

    PubMed

    Begum, Shamim A; Batista, Jacimaria R

    2014-01-01

    Microbial selection in an enhanced biological phosphorus removal system was investigated in a laboratory-scale sequencing batch reactor fed exclusively with butyrate as a carbon source. As reported in the few previous studies, butyrate uptake was slow and phosphorus (P) release occurred during the entire anaerobic period. Polyphosphate-accumulating organism (PAO), i.e. Candidatus Accumulibacter phosphatis (named as Accumulibacter), glycogen-accumulating organisms (GAOs), i.e. Candidatus Competibacter phosphatis (named as Competibacter) and Defluviicoccus-related, tetrad-forming alphaproteobacteria (named as Defluviicoccus) were identified using fluorescence in situ hybridization analysis. The results show that Accumulibacter and Defluviicoccus were selected in the butyrate-fed reactor, whereas Competibacter was not selected. P removal was efficient at the beginning of the experiment with an increasing percentage relative abundance (% RA) of PAOs. The % RA of Accumulibacter and Defluviicoccus increased from 13% to 50% and 8% to 16%, respectively, and the % RA of Competibacter decreased from 8% to 2% during the experiment. After 6 weeks, P removal deteriorated with the poor correlation between the percentage of P removal and % RA of GAOs.

  11. Performance enhancement and background removal to improve dynamic phase imaging of biological organisms

    PubMed Central

    Creath, Katherine; Goldstein, Goldie

    2014-01-01

    This paper describes recent advances in enhancing optical imaging performance and removal of background shape for a new, novel interference dynamic microscope system. The specially designed optical system enables instantaneous 4-dimensional video measurements of dynamic motions within and among live cells without the need for labels or contrast agents. This instrument utilizes a pixelated phase mask enabling simultaneous measurement of multiple interference patterns. It incorporates the polarization properties of light to capture phase image movies in real time at video rates enabling tracking of dynamic motions and volumetric changes. Optical thickness data are obtained from phase images after processing to remove the background surface shape to quantify changes in cell position and volume. Data from a number of different biological organisms will be presented. These data highlight examples of the optical image quality and image processing. PMID:23366597

  12. Effects of glucose on the performance of enhanced biological phosphorus removal activated sludge enriched with acetate.

    PubMed

    Gebremariam, Seyoum Yami; Beutel, Marc W; Christian, David; Hess, Thomas F

    2012-10-01

    The effects of glucose on enhanced biological phosphorus removal (EBPR) activated sludge enriched with acetate was investigated using sequencing batch reactors. A glucose/acetate mixture was serially added to the test reactor in ratios of 25/75%, 50/50%, and 75/25% and the EBPR activity was compared to the control reactor fed with 100% acetate. P removal increased at a statistically significant level to a near-complete in the test reactor when the mixture increased to 50/50%. However, EBPR deteriorated when the glucose/acetate mixture increased to 75/25% in the test reactor and when the control reactor abruptly switched to 100% glucose. These results, in contrast to the EBPR conventional wisdom, suggest that the addition of glucose at moderate levels in wastewaters does not impede and may enhance EBPR, and that glucose waste products should be explored as an economical sustainable alternative when COD enhancement of EBPR is needed.

  13. [Kinetic simulation of enhanced biological phosphorus removal with fermentation broth as carbon source].

    PubMed

    Zhang, Chao; Chen, Yin-Guang

    2013-07-01

    As a high-quality carbon source, fermentation broth could promote the phosphorus removal efficiency in enhanced biological phosphorus removal (EBPR). The transformation of substrates in EBPR fed with fermentation broth was well simulated using the modified activated sludge model No. 2 (ASM2) based on the carbon source metabolism. When fermentation broth was used as the sole carbon source, it was found that heterotrophic bacteria acted as a promoter rather than a competitor to the phosphorus accumulating organisms (PAO). When fermentation broth was used as a supplementary carbon source of real municipal wastewater, the wastewater composition was optimized for PAO growth; and the PAO concentration, which was increased by 3.3 times compared to that in EBPR fed with solely real municipal wastewater, accounting for about 40% of the total biomass in the reactor.

  14. An observation on sludge granulation in an enhanced biological phosphorus removal process.

    PubMed

    Ong, Ying Hui; Chua, Adeline Seak May; Lee, Boon Pin; Ngoh, Gek Cheng; Hashim, Mohd Ali

    2012-01-01

    A sequencing batch reactor (SBR) seeded with flocculated sludge and fed with synthetic wastewater was operated for an enhanced biological phosphorus removal (EBPR) process. Eight weeks after reactor startup, sludge granules were observed. The granules had a diameter of 0.5 to 3.0 mm and were brownish in color and spherical or ellipsoidal in shape. No significant change was observed in sludge granule size when operational pH was changed from 7 to 8. The 208-day continuous operation of the SBR showed that sludge granules were stably maintained with a sludge volume index (SVI) between 30 to 55 mL/g while securing a removal efficiency of 83% for carbon and 97% for phosphorus. Fluorescent in situ hybridization (FISH) confirmed the enrichment of polyphosphate accumulating organisms (PAOs) in the SBR. The observations of sludge granulation in this study encourage further studies in the development of granules-based EBPR process.

  15. Biological treatment process for removing petroleum hydrocarbons from oil field produced waters

    SciTech Connect

    Tellez, G.; Khandan, N.

    1995-12-31

    The feasibility of removing petroleum hydrocarbons from oil fields produced waters using biological treatment was evaluated under laboratory and field conditions. Based on previous laboratory studies, a field-scale prototype system was designed and operated over a period of four months. Two different sources of produced waters were tested in this field study under various continuous flow rates ranging from 375 1/D to 1,800 1/D. One source of produced water was an open storage pit; the other, a closed storage tank. The TDS concentrations of these sources exceeded 50,000 mg/l; total n-alkanes exceeded 100 mg/l; total petroleum hydrocarbons exceeded 125 mg/l; and total BTEX exceeded 3 mg/l. Removals of total n-alkanes, total petroleum hydrocarbons, and BTEX remained consistently high over 99%. During these tests, the energy costs averaged $0.20/bbl at 12 bbl/D.

  16. 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.

  17. Microbial communities involved in biological ammonium removal from coal combustion wastewaters.

    PubMed

    Vishnivetskaya, Tatiana A; Fisher, L Suzanne; Brodie, Greg A; Phelps, Tommy J

    2013-07-01

    The efficiency of a novel integrated treatment system for biological removal of ammonium, nitrite, nitrate, and heavy metals from fossil power plant effluent was evaluated. Microbial communities were analyzed using bacterial and archaeal 16S rRNA gene clone libraries (Sanger sequences) and 454 pyrosequencing technology. While seasonal changes in microbial community composition were observed, the significant (P = 0.001) changes in bacterial and archaeal communities were consistent with variations in ammonium concentration. Phylogenetic analysis of 16S rRNA gene sequences revealed an increase of potential ammonium-oxidizing bacteria (AOB), Nitrosomonas, Nitrosococcus, Planctomycetes, and OD1, in samples with elevated ammonium concentration. Other bacteria, such as Nitrospira, Nitrococcus, Nitrobacter, Thiobacillus, ε-Proteobacteria, Firmicutes, and Acidobacteria, which play roles in nitrification and denitrification, were also detected. The AOB oxidized 56 % of the ammonium with the concomitant increase in nitrite and ultimately nitrate in the trickling filters at the beginning of the treatment system. Thermoprotei within the phylum Crenarchaeota thrived in the splitter box and especially in zero-valent iron extraction trenches, where an additional 25 % of the ammonium was removed. The potential ammonium-oxidizing Archaea (AOA) (Candidatus Nitrosocaldus) were detected towards the downstream end of the treatment system. The design of an integrated treatment system consisting of trickling filters, zero-valent iron reaction cells, settling pond, and anaerobic wetlands was efficient for the biological removal of ammonium and several other contaminants from wastewater generated at a coal burning power plant equipped with selective catalytic reducers for nitrogen oxide removal.

  18. Application of vascular aquatic plants for pollution removal, energy and food production in a biological system

    NASA Technical Reports Server (NTRS)

    Wolverton, B. C.; Barlow, R. M.; Mcdonald, R. C.

    1975-01-01

    Vascular aquatic plants such as water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb., when utilized in a controlled biological system (including a regular program of harvesting to achieve maximum growth and pollution removal efficiency), may represent a remarkably efficient and inexpensive filtration and disposal system for toxic materials and sewage released into waters near urban and industrial areas. The harvested and processed plant materials are sources of energy, fertilizer, animal feed, and human food. Such a system has industrial, municipal, and agricultural applications.

  19. Intensification of ammonia removal from waste water in biologically active zeolitic ion exchange columns.

    PubMed

    Almutairi, Azel; Weatherley, Laurence R

    2015-09-01

    The use of nitrification filters for the removal of ammonium ion from waste-water is an established technology deployed extensively in municipal water treatment, in industrial water treatment and in applications such as fish farming. The process involves the development of immobilized bacterial films on a solid packing support, which is designed to provide a suitable host for the film, and allow supply of oxygen to promote aerobic action. Removal of ammonia and nitrite is increasingly necessary to meet drinking water and discharge standards being applied in the US, Europe and other places. Ion-exchange techniques are also effective for removal of ammonia (as the ammonium ion) from waste water and have the advantage of fast start-up times compared to biological filtration which in some cases may take several weeks to be fully operational. Here we explore the performance of ion exchange columns in which nitrifying bacteria are cultivated, with the goal of a "combined" process involving simultaneous ion-exchange and nitrification, intensified by in-situ aeration with a novel membrane module. There were three experimental goals. Firstly, ion exchange zeolites were characterized and prepared for comparative column breakthrough studies for ammonia removal. Secondly effective in-situ aeration for promotion of nitrifying bacterial growth was studied using a number of different membranes including polyethersulfone (PES), polypropylene (PP), nylon, and polytetra-fluoroethylene (PTFE). Thirdly the breakthrough performance of ion exchange columns filled with zeolite in the presence of aeration and in the presence of nitrifying bacteria was determined to establish the influence of biomass, and aeration upon breakthrough during ammonium ion uptake. The methodology adopted included screening of two types of the naturally occuring zeolite clinoptilolite for effective ammonia removal in continuous ion-exchange columns. Next, the performance of fixed beds of clinoptilolite in the

  20. Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

    NASA Astrophysics Data System (ADS)

    He, Shijun; Wang, Jianlong; Ye, Longfei; Zhang, Youxue; Yu, Jiang

    2014-12-01

    The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.

  1. 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

  2. Biological phosphorus removal in anoxic-aerobic sequencing batch reactor with starch as sole carbon source.

    PubMed

    Luo, Dacheng; Yuan, Linjiang; Liu, Lun; Chai, Lu; Wang, Xin

    2017-01-01

    In traditional biological phosphorus removal (BPR), phosphorus release in anaerobic stage is the prerequisite of phosphorus excessive uptake in aerobic conditions. Moreover, when low molecular weight of the organic substance such as volatile fatty acids (VFAs) is scarce in bulk liquid or anaerobic condition does not exist, phosphate accumulating organisms (PAOs) have difficulty removing phosphorus. However, in this work, phosphorus removal in two anoxic-aerobic sequencing batch reactors (SBRs) was observed when starch was supplied as a sole carbon source. The relations of the BPR with idle period were investigated in the two identical SBRs; the idle times were set to 0.5 hr (R1) and 4 hr (R2), respectively. Results of the study showed that, in the two SBRs, phosphorus concentrations of 0.26-3.11 mg/L in effluent were obtained after aeration when phosphorus concentration in influent was about 8 mg/L. Moreover, lower accumulations/transformations of polyhydroxyalkanoates (PHAs) and higher transformation of glycogen occurred in the SBRs, indicating that glycogen was the main energy source that was different from the traditional mechanism of BPR. Under the different idle time, the phosphorus removal was a little different. In R2, which had a longer idle period, phosphorus release was very obvious just as occurs in a anaerobic-aerobic regime, but there was a special phenomenon of chemical oxygen demand increase, while VFAs had no notable change. It is speculated that PAOs can assimilate organic compounds in the mixed liquor, which were generated from glycolysis by fermentative organisms, coupled with phosphorus release. In R1, which had a very short idle period, anaerobic condition did not exist; phosphorus removal rate reached 63%. It is implied that a new metabolic pathway can occur even without anaerobic phosphorus release when starch is supplied as the sole carbon source.

  3. 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.

  4. Evaluating our understanding of the biological carbon pump using the transport matrix method and global nutrient distributions.

    NASA Astrophysics Data System (ADS)

    Bernardello, Raffaele; Martin, Adrian; Khatiwala, Samar; Kriest, Iris; Henson, Stephanie; Dunne, John; Totterdell, Ian; Allen, Icarus; Yool, Andrew

    2015-04-01

    Global net primary production by marine phytoplankton plays a key role in the Earth system, fuelling the marine ecosystem and supporting resources such as fisheries. A fraction of the resulting organic material sinks out of the euphotic zone as 'export production', sequestering large amounts of carbon at depth, away from the atmosphere. Model studies have demonstrated that atmospheric pCO2 concentrations can be very sensitive to small changes in the depth at which this organic material is remineralised into CO2 and nutrients. The accuracy of parameterisations for remineralisation has often been assessed by direct comparison of simulated and sparse observed fluxes of sinking material. The consequences of remineralisation, i.e. the global distribution of inorganic nutrients, provide a much stronger test of our knowledge concerning the impact of remineralisation on ocean nutrient cycles because they are much more densely sampled. In this study, we investigate how alternative paradigms for the Biological Carbon Pump (BCP) have distinctive signatures in the consequent global distribution of nutrients. We compare several combinations of parameterisations for export production and remineralisation within two different representations of ocean circulation using the Transport Matrix Method (Khatiwala, 2007). Export production is represented using an NPZD-DOP model (Kriest et al., 2010) and three remote sensing-derived estimates while remineralisation is represented by either constant or spatially variable values of the Martin's curve exponent (Martin et al., 1987). In order to evaluate the ability of each export-remineralisation combination to correctly represent the BCP, we introduce a set of diagnostics to allow the intercomparison between in-situ data and simulations. These diagnostics are based on both nutrient fields and water masses and are designed to minimize the influence of biases originating from the representation of ocean circulation on the model

  5. Nitrogen Eutrophication on the Colorado Plateau: Using Biological Indicators to Detect Nutrient Enrichment in the Grand Canyon Region

    NASA Astrophysics Data System (ADS)

    Kenkel, J. A.; Johnson, N.; Hultine, K. R.; Sesnie, S.; Sisk, T.

    2012-12-01

    Human activities have more than doubled the availability of biologically reactive forms of nitrogen (N) since the industrial and agricultural revolutions. Though N is an important plant nutrient, increased deposition initiates a cascade of deleterious effects including ecosystem acidification, biodiversity loss, and increased smog and haze. Atmospheric pollution continues to threaten the air quality of the 16 Class 1 Wilderness areas on the Colorado Plateau, including Grand Canyon National Park (GCNP). However, the ecological impacts of N deposition in these historically N-limited, nutrient sensitive arid regions, are little- known. Here, we report baseline atmospheric and terrestrial responses to anthropogenic N deposition derived from vehicular exhaust in GCNP and long-range deposition from a local coal-fired power plant, the Navajo Generating Station (NGS). We used passive air samplers, natural abundance δ15N stable isotope analysis, and nutrient analysis to observe N patterns in air, soils, and pinyon pine (Pinus edulis) foliage. In GCNP, samples were collected from ten sites over an eight-month period in areas of projected low to high vehicular N deposition (i.e. distance from primary roadways). On the Paria Plateau, northeast of GCNP and in close proximity to the NGS, samples were collected along a distance gradient from the NGS, across the Plateau. In both study areas, atmospheric deposition, as well as soil and pine- needle nutrient concentrations show significant negative relationships with increased distance from N-source (p<0.05). In heavily trafficked sites of GCNP, atmospheric nitrogen oxides (NOx) were 65% lower at 30m compared to the roadside. Likewise, on the Paria, NOx were 54% lower at 50km compared to 25km from NGS (p<0.01; R2 =0.87, for GCNP and the Paria, respectively). In GCNP, soil δ15N, and pinyon needle δ15N decrease significantly 30m from the roadside (18%, F= 4.07, p<0.05; 40%, F=4.34, p<0.05). On the Paria Plateau, soil δ15N, C

  6. Effect of influent nutrient ratios and hydraulic retention time (HRT) on simultaneous phosphorus and nitrogen removal in a two-sludge sequencing batch reactor process.

    PubMed

    Wang, Yayi; Peng, Yongzhen; Stephenson, Tom

    2009-07-01

    A laboratory-scale anaerobic-anoxic/nitrification sequencing batch reactor (A(2)N-SBR) fed with domestic wastewater was operated to examine the effect of varying ratios of influent COD/P, COD/TN and TN/P on the nutrient removal. With the increased COD/P, the phosphorus removals exhibited an upward trend. The influent TN/P ratios had a positive linear correlation with the phosphorus removal efficiencies, mainly because nitrates act as electron acceptors for the phosphorus uptake in the A(2)N-SBR. Moreover, it was found that lower COD/TN ratio, e.g. 3.5, did not significantly weaken the phosphorus removal, though the nitrogen removal first decreased greatly. The optimal phosphorus and nitrogen removals of 94% and 91%, respectively were achieved with influent COD/P and COD/TN ratios of 19.9 and 9.9, respectively. Additionally, a real-time control strategy for A(2)N-SBR can be undertaken based on some characteristic points of pH, redox potential (ORP) and dissolved oxygen (DO) profiles in order to obtain the optimum hydraulic retention time (HRT) and improve the operating reliability.

  7. Effects of an urban wetland on sediment and nutrient loads in runoff

    USGS Publications Warehouse

    Brown, R.G.

    1984-01-01

    Retention of sediment and nutrient loads in the wetland was associated with sedimentation processes. Dissolved nutrients generally were not retained in the wetland because the residence time of water passing through was not long enough for removal by biological processes. Effectiveness of the wetland in retaining sediment and nutrient loads in runoff varies annually. Long-term and short-term impacts of the retention of sediment and nutrients in the wetland on wetland flora and fauna are unknown.

  8. Biological redox cycling of iron in nontronite and its potential application in nitrate removal.

    PubMed

    Zhao, Linduo; Dong, Hailiang; Kukkadapu, Ravi K; Zeng, Qiang; Edelmann, Richard E; Pentrák, Martin; Agrawal, Abinash

    2015-05-05

    Biological redox cycling of structural Fe in phyllosilicates is an important but poorly understood process. The objective of this research was to study microbially mediated redox cycles of Fe in nontronite (NAu-2). During the reduction phase, structural Fe(III) in NAu-2 served as electron acceptor, lactate as electron donor, AQDS as electron shuttle, and dissimilatory Fe(III)-reducing bacterium Shewanella putrefaciens CN32 as mediator in bicarbonate- and PIPES-buffered media. During the oxidation phase, biogenic Fe(II) served as electron donor and nitrate as electron acceptor. Nitrate-dependent Fe(II)-oxidizing bacterium Pseudogulbenkiania sp. strain 2002 was added as mediator in the same media. For all three cycles, structural Fe in NAu-2 was able to reversibly undergo three redox cycles without significant dissolution. Fe(II) in bioreduced samples occurred in two distinct environments, at edges and in the interior of the NAu-2 structure. Nitrate reduction to nitrogen gas was coupled with oxidation of edge-Fe(II) and part of interior-Fe(II) under both buffer conditions, and its extent and rate did not change with Fe redox cycles. These results suggest that biological redox cycling of structural Fe in phyllosilicates is a reversible process and has important implications for biogeochemical cycles of carbon, nitrogen, and other nutrients in natural environments.

  9. Integration of photocatalysis and biological treatment for azo dye removal--application to AR183.

    PubMed

    Chebli, Derradji; Fourcade, Florence; Brosillon, Stephan; Nacef, Saci; Amrane, Abdeltif

    2011-04-01

    The feasibility of coupling photocatalysis with biological treatment to treat effluents containing azo dyes was examined in this work. With this aim, the degradation of Acid Red 183 was investigated. The very low biodegradability of AR183 was confirmed beforehand by measuring the biological oxygen demand (BOD5). Photocatalysis experiments were carried out in a closed-loop step photoreactor. The reactor walls were covered by TiO2 catalyst coated on non-woven paper, and the effluent flowed over the photocatalyst as a thin falling film. The removal of the dye was 82.7% after 4 h, and a quasi-complete decolorization (98.5%) was obtained for 10 h of irradiation (initial concentration 100 mg L(-1)). The decrease in concentration followed pseudo-first-order kinetics, with a constant k of 0.47 h(-1). Mineralization and oxidation yields were 80% and 75%, respectively, after 10 h of pretreatment. Therefore, even if target compound oxidation occurs (COD removal), indicating a modification to the chemical structure, the concomitant high mineralization was not in favour of subsequent microbial growth. The BOD5 measurement confirmed the non-biodegradability of the irradiated solution, which remained toxic since the EC50 decreased from 35 to 3 mg L(-1). The proposed integrated process appeared, therefore, to be not relevant for the treatment of AR183. However, this result should be confirmed for other azo dyes.

  10. Biological removal of the xenobiotic trichloroethylene (TCE) through cometabolism in nitrifying systems.

    PubMed

    Kocamemi, B Alpaslan; Ceçen, F

    2010-01-01

    In the present study, cometabolic TCE degradation was evaluated using NH(4)-N as the growth-substrate. At initial TCE concentrations up to 845 microg/L, TCE degradation followed first-order kinetics. The increase in ammonium utilization rate favored the degradation of TCE. This ensured that biological transformation of TCE in nitrifying systems is accomplished through a cometabolic pathway by the catalysis of non-specific ammonia oxygenase enzyme of nitrifiers. The transformation yield (T(y)) of TCE, the amount of TCE degraded per unit mass of NH(4)-N, strongly depended on the initial NH(4)-N and TCE concentrations. In order to allow a rough estimation of TCE removal and nitrification at different influent TCE and NH(4)-N concentrations, a linear relationship was developed between 1/T(y) and the initial NH(4)-N/TCE ratio. The estimated T(y) values lead to the conclusion that nitrifying systems are promising candidates for biological removal of TCE through cometabolism.

  11. BIOLOGICALLY-MEDIATED REMOVAL AND RECOVERY OF PLUTONIUM FROM CONTAMINATED SOIL

    SciTech Connect

    Jerger, Douglas E., Ph.D.,; Alperin, Edward S., QEP,; Holmes, Robert G., Ph.D.

    2003-02-27

    An innovative biological treatment technology successfully reduced plutonium concentration in soil from the Nevada Test Site (NTS) by over 80%. The final volume of plutonium-contaminated material that required disposal was reduced by over 90%. These results, achieved by an independent testing laboratory, confirm the results reported previously using NTS soil. In the previous test a 2530-gram sample of soil (350 to 400 pCi/g Pu) resulted in production of 131 grams of sludge (6,320 pCi/ g Pu) and a treated soil containing 72 pCi/g of Pu. The technology is based on the biological acidification of the soil and subsequent removal of the plutonium and other dissolved metals by a low volume, low energy water leaching process. The leachate is treated in a sulfate-reducing bioreactor to precipitate the metals as metal sulfides. Water may be recycled as process water or disposed since the treatment process removes over 99% of the dissolved metals including plutonium from the water. The plutonium is contained as a stable sludge that can be containerized for final disposal. Full-scale process costs have been developed which employ widely used treatment technologies such as aerated soil piles (biopiles) and bioreactors. The process costs were less than $10 per cubic foot, which were 40 to 50% lower than the baseline costs for the treatment of the NTS soil. The equipment and materials for water and sludge treatment and soil handling are commercially available.

  12. Calcium effect on the metabolic pathway of phosphorus accumulating organisms in enhanced biological phosphorus removal systems.

    PubMed

    Zhang, Hai-Ling; Sheng, Guo-Ping; Fang, Wei; Wang, Yong-Peng; Fang, Cai-Yun; Shao, Li-Min; Yu, Han-Qing

    2015-11-01

    Phosphorus accumulating organisms (PAOs) have been found to act as glycogen-accumulating organisms (GAOs) under certain conditions, thus, the deterioration in the performance of enhanced biological phosphorus removal systems is not always attributed to the proliferation of GAOs. In this work, the effects of calcium on the metabolic pathway of PAOs were explored. It was found that when the influent Ca(2+) concentration was elevated, the tendency and extent of extracellular calcium phosphate precipitation increased, and the intracellular inert Ca-bound polyphosphate was synthesized, while the microbial population remained almost unchanged. The changes in the ratios of phosphorus released/acetate uptaken, the glycogen degraded/acetate uptaken and the poly-β-hydroxyalkanoates synthesized/acetate uptaken during the anaerobic period confirm that, as the influent Ca(2+) concentration was increased, the polyphosphate-accumulating metabolism was partially shifted to the glycogen-accumulating metabolism. At an influent Ca(2+) around 50 mg/L, in addition to the extracellular calcium phosphate precipitation, the intracellular inert Ca-bound polyphosphate synthesis might also be involved in the metabolic change of PAOs. The results of the present work would be beneficial to better understand the biochemical metabolism of PAOs in enhanced biological phosphorus removal systems.

  13. Biological Nitrogen Removal through Nitritation Coupled with Thiosulfate-Driven Denitritation

    NASA Astrophysics Data System (ADS)

    Qian, Jin; Zhou, Junmei; Zhang, Zhen; Liu, Rulong; Wang, Qilin

    2016-06-01

    A novel biological nitrogen removal system based on nitritation coupled with thiosulfate-driven denitritation (Nitritation-TDD) was developed to achieve a high nitrogen removal rate and low sludge production. A nitritation sequential batch reactor (nitritation SBR) and an anoxic up-flow sludge bed (AnUSB) reactor were applied for effective nitritation and denitritation, respectively. Above 75% nitrite was accumulated in the nitritation SBR with an influent ammonia loading rate of 0.43 kg N/d/m3. During Nitritation-TDD operation, particle sizes (d50) of the sludge decreased from 406 to 225 um in nitritation SBR and from 327–183 um in AnUSB reactor. Pyrosequencing tests revealed that ammonium-oxidizing bacteria (AOB) population was stabilized at approximately 7.0% (calculated as population of AOB-related genus divided by the total microbial population) in the nitritation SBR. In contrast, nitrite-oxidizing bacteria (NOB) population decreased from 6.5–0.6% over the same time, indicating the effective nitrite accumulation in the nitritation SBR. Thiobacillus, accounting for 34.2% in the AnUSB reactor, was mainly responsible for nitrogen removal via autotrophic denitritation, using an external source of thiosulfate as electron donor. Also, it was found that free nitrous acid could directly affect the denitritation activity.

  14. Could nitrite/free nitrous acid favour GAOs over PAOs in enhanced biological phosphorus removal systems?

    PubMed

    Pijuan, M; Ye, L; Yuan, Z

    2011-01-01

    Enhanced biological phosphorus removal (EBPR) normally occurs together with nitrogen removal in wastewater treatment plants (WWTPs). In recent years, efforts have been devoted to remove nitrogen via the nitrite pathway (oxidation of ammonia to nitrite and reduction of nitrite to nitrogen gas without going through nitrate), reducing the requirement for carbon and oxygen in the plant. However nitrite and free nitrous acid (FNA), the protonated species of nitrite, have been shown to cause EBPR deterioration under certain concentrations. This study provides a direct comparison between the different levels of FNA inhibition in the aerobic processes of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) by reviewing the studies published in this area. Also, new data is presented assessing the FNA effect on the anaerobic metabolism of these two groups of bacteria. Overall, FNA has shown inhibitory effects on most of the processes involved in the metabolism of PAOs and GAOs. However, the inhibition-initiation levels are different between different processes and, even more importantly between the two groups. In general, PAOs appear to be more affected than GAOs at the same level of FNA, thus giving GAOs competitive advantage over PAOs in EBPR systems when nitrite is present.

  15. Roles of extracellular polymeric substances in enhanced biological phosphorus removal process.

    PubMed

    Li, Wen-Wei; Zhang, Hai-Ling; Sheng, Guo-Ping; Yu, Han-Qing

    2015-12-01

    Enhanced biological phosphorus removal (EBPR) process is known to mainly rely on the ability of phosphorus-accumulating organisms to take up, transform and store excess amount of phosphorus (P) inside the cells. However, recent studies have revealed considerable accumulation of P also in the extracellular polymeric substances (EPS) of sludge, implying a non-negligible role of EPS in P removal by EBPR sludge. However, the contribution of EPS to P uptake and the forms of accumulated extracellular P vary substantially in different studies, and the underlying mechanism of P transformation and transportation in EPS remains poorly understood. This review provides a new recognition into the P removal process in EBPR system by incorporating the role of EPS. It overviews on the characteristics of P accumulation in EPS, explores the mechanism of P transformation and transportation in EBPR sludge and EPS, summarizes the main influential factors for the P-accumulation properties of EPS, and discusses the remaining knowledge gaps and needed future efforts that may lead to better understanding and use of such an EPS role for maximizing P recovery from wastewater.

  16. Microbial selection on enhanced biological phosphorus removal systems fed exclusively with glucose.

    PubMed

    Begum, Shamim A; Batista, Jacimaria R

    2012-05-01

    The microbial selection on an enhanced biological phosphorus removal (EBPR) system was investigated in a laboratory-scale sequencing batch reactor fed exclusively with glucose as the carbon source. Fluorescence In Situ Hybridization analysis was performed to target two polyphosphate accumulating organisms (PAOs) (i.e., Candidatus Accumulibacter phosphatis and Microlunatus phosphovorus) and two glycogen accumulating organisms (GAOs) (i.e., Candidatus Competibacter phosphatis and Micropruina glycogenica). The results show that glucose might not select for Candidatus Accumulibacter phosphatis. However, Microlunatus phosphovorus, Candidatus Competibacter phosphatis, and Micropruina glycogenica might be selected. The highest percent relative abundance (% RA) of Candidatus Accumulibacter phosphatis was about 42%; this occurred at the beginning of the experimental period when phosphorus removal was efficient. However, the % RA of these bacteria decreased, reaching below 4% at the end of the run. The maximum % RA of Microlunatus phosphovorus, Candidatus Competibacter phosphatis, and Micropruina glycogenica was about 21, 37, 17%, respectively. It appears that a higher glucose concentration might be detrimental for Microlunatus phosphovorus and Micropruina glycogenica. Results also indicate a dominance of GAOs over PAOs when EBPR systems are fed with glucose. It is possible that the GAOs outcompete the PAOs at low pH values; it has been reported that at low pH, GAOs use glycogen as the energy source to uptake glucose. As a result, P-removal deteriorated. Therefore, glucose is not a strong candidate as a carbon source to supplement EBPR systems that do not contain sufficient volatile fatty acids.

  17. Biological Nitrogen Removal through Nitritation Coupled with Thiosulfate-Driven Denitritation

    PubMed Central

    Qian, Jin; Zhou, Junmei; Zhang, Zhen; Liu, Rulong; Wang, Qilin

    2016-01-01

    A novel biological nitrogen removal system based on nitritation coupled with thiosulfate-driven denitritation (Nitritation-TDD) was developed to achieve a high nitrogen removal rate and low sludge production. A nitritation sequential batch reactor (nitritation SBR) and an anoxic up-flow sludge bed (AnUSB) reactor were applied for effective nitritation and denitritation, respectively. Above 75% nitrite was accumulated in the nitritation SBR with an influent ammonia loading rate of 0.43 kg N/d/m3. During Nitritation-TDD operation, particle sizes (d50) of the sludge decreased from 406 to 225 um in nitritation SBR and from 327–183 um in AnUSB reactor. Pyrosequencing tests revealed that ammonium-oxidizing bacteria (AOB) population was stabilized at approximately 7.0% (calculated as population of AOB-related genus divided by the total microbial population) in the nitritation SBR. In contrast, nitrite-oxidizing bacteria (NOB) population decreased from 6.5–0.6% over the same time, indicating the effective nitrite accumulation in the nitritation SBR. Thiobacillus, accounting for 34.2% in the AnUSB reactor, was mainly responsible for nitrogen removal via autotrophic denitritation, using an external source of thiosulfate as electron donor. Also, it was found that free nitrous acid could directly affect the denitritation activity. PMID:27272192

  18. Biological sulfate removal from construction and demolition debris leachate: effect of bioreactor configuration.

    PubMed

    Kijjanapanich, Pimluck; Do, Anh Tien; Annachhatre, Ajit P; Esposito, Giovanni; Yeh, Daniel H; Lens, Piet N L

    2014-03-30

    Due to the contamination of construction and demolition debris (CDD) by gypsum drywall, especially, its sand fraction (CDD sand, CDDS), the sulfate content in CDDS exceeds the posed limit of the maximum amount of sulfate present in building sand (1.73 g sulfate per kg of sand for the Netherlands). Therefore, the CDDS cannot be reused for construction. The CDDS has to be washed in order to remove most of the impurities and to obtain the right sulfate content, thus generating a leachate, containing high sulfate and calcium concentrations. This study aimed at developing a biological sulfate reduction system for CDDS leachate treatment and compared three different reactor configurations for the sulfate reduction step: the upflow anaerobic sludge blanket (UASB) reactor, inverse fluidized bed (IFB) reactor and gas lift anaerobic membrane bioreactor (GL-AnMBR). This investigation demonstrated that all three systems can be applied for the treatment of CDDS leachate. The highest sulfate removal efficiency of 75-85% was achieved at a hydraulic retention time (HRT) of 15.5h. A high calcium concentration up to 1,000 mg L(-1) did not give any adverse effect on the sulfate removal efficiency of the IFB and GL-AnMBR systems.

  19. A Biophysicochemical Model for NO Removal by the Chemical Absorption-Biological Reduction Integrated Process.

    PubMed

    Zhao, Jingkai; Xia, Yinfeng; Li, Meifang; Li, Sujing; Li, Wei; Zhang, Shihan

    2016-08-16

    The chemical absorption-biological reduction (CABR) integrated process is regarded as a promising technology for NOx removal from flue gas. To advance the scale-up of the CABR process, a mathematic model based on mass transfer with reaction in the gas, liquid, and biofilm was developed to simulate and predict the NOx removal by the CABR system in a biotrickling filter. The developed model was validated by the experimental results and subsequently was used to predict the system performance under different operating conditions, such as NO and O2 concentration and gas and liquid flow rate. NO distribution in the gas phase along the biotrickling filter was also modeled and predicted. On the basis of the modeling results, the liquid flow rate and total iron concentration were optimized to achieve >90% NO removal efficiency. Furthermore, sensitivity analysis of the model revealed that the performance of the CABR process was controlled by the bioreduction activity of Fe(III)EDTA. This work will provide the guideline for the design and operation of the CABR process in the industrial application.

  20. Biological Phosphorus Removal During High-Rate, Low-Temperature, Anaerobic Digestion of Wastewater

    PubMed Central

    Keating, Ciara; Chin, Jason P.; Hughes, Dermot; Manesiotis, Panagiotis; Cysneiros, Denise; Mahony, Therese; Smith, Cindy J.; McGrath, John W.; O’Flaherty, Vincent

    2016-01-01

    We report, for the first time, extensive biologically mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12°C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis revealed the accumulation of elemental phosphorus (∼2%) within the sludge bed and fixed-film biofilms. 4′, 6-diamidino-2-phenylindole (DAPI) staining indicated phosphorus accumulation was biological in nature and mediated through the formation of intracellular inorganic polyphosphate (polyP) granules within these biofilms. DAPI staining further indicated that polyP accumulation was rarely associated with free cells. Efficient and consistent chemical oxygen demand (COD) removal was recorded, throughout the 732-day trial, at applied organic loading rates between 0.4 and 1.5 kg COD m-3 d-1 and hydraulic retention times of 8–24 h, while phosphate removal efficiency ranged from 28 to 78% on average per phase. Analysis of protein hydrolysis kinetics and the methanogenic activity profiles of the biomass revealed the development, at 12°C, of active hydrolytic and methanogenic populations. Temporal microbial changes were monitored using Illumina MiSeq analysis of bacterial and archaeal 16S rRNA gene sequences. The dominant bacterial phyla present in the biomass at the conclusion of the trial were the Proteobacteria and Firmicutes and the dominant archaeal genus was Methanosaeta. Trichococcus and Flavobacterium populations, previously associated with low temperature protein degradation, developed in the reactor biomass. The presence of previously characterized polyphosphate accumulating organisms (PAOs) such as Rhodocyclus, Chromatiales, Actinobacter, and Acinetobacter was recorded

  1. Biological Phosphorus Removal During High-Rate, Low-Temperature, Anaerobic Digestion of Wastewater.

    PubMed

    Keating, Ciara; Chin, Jason P; Hughes, Dermot; Manesiotis, Panagiotis; Cysneiros, Denise; Mahony, Therese; Smith, Cindy J; McGrath, John W; O'Flaherty, Vincent

    2016-01-01

    We report, for the first time, extensive biologically mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12°C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis revealed the accumulation of elemental phosphorus (∼2%) within the sludge bed and fixed-film biofilms. 4', 6-diamidino-2-phenylindole (DAPI) staining indicated phosphorus accumulation was biological in nature and mediated through the formation of intracellular inorganic polyphosphate (polyP) granules within these biofilms. DAPI staining further indicated that polyP accumulation was rarely associated with free cells. Efficient and consistent chemical oxygen demand (COD) removal was recorded, throughout the 732-day trial, at applied organic loading rates between 0.4 and 1.5 kg COD m(-3) d(-1) and hydraulic retention times of 8-24 h, while phosphate removal efficiency ranged from 28 to 78% on average per phase. Analysis of protein hydrolysis kinetics and the methanogenic activity profiles of the biomass revealed the development, at 12°C, of active hydrolytic and methanogenic populations. Temporal microbial changes were monitored using Illumina MiSeq analysis of bacterial and archaeal 16S rRNA gene sequences. The dominant bacterial phyla present in the biomass at the conclusion of the trial were the Proteobacteria and Firmicutes and the dominant archaeal genus was Methanosaeta. Trichococcus and Flavobacterium populations, previously associated with low temperature protein degradation, developed in the reactor biomass. The presence of previously characterized polyphosphate accumulating organisms (PAOs) such as Rhodocyclus, Chromatiales, Actinobacter, and Acinetobacter was recorded

  2. Biological flocculation of suspended particles in nutrient-rich aqueous ecosystems

    NASA Astrophysics Data System (ADS)

    Maggi, Federico

    2009-09-01

    SummaryWe describe the development and testing of a mechanistic model (BFLOC) to predict the average size of sediment aggregates in nutrient-rich aqueous ecosystems. The original capability of BFLOC is to couple turbulence-induced flocculation of suspended minerals and micro-organisms with the nutrient-related dynamics of aggregate-attached micro-organisms. The model, calibrated and validated against the average floc size recorded at two stations in the Belgian North Sea [Fettweis, M., Francken, F., Pison V., Ven den Eynde, D., 2006. Suspended particulate matter dynamics and aggregate sizes in a high turbidity area. Marine Geology 235, 63-74], closely captured site conditions and significantly clarified interpretation of field measurements. Modeling results indicated that an accurate prediction of time-varying floc sizes was possible only by taking into account the organic fraction of the suspended particle matter and the micro-organism colonization of the floc micro-environment. BFLOC showed that the floc excess density strongly correlated with the floc biomass volume, while the settling velocity strongly correlated with the floc mineral volume. We noticed that the settling velocity was poorly correlated with the total floc volume (and floc size), suggesting a revision of current methods that assess suspended matter deposition uniquely on the basis of the floc size. Additionally, various hypotheses tested with BFLOC suggested that the effect of aggregate-attached biomass on aggregation and breakup rates was very small when it was accounted for with a first-order description. More generally, the sediment and biomass parameters found here were nearly site independent suggesting that the mechanistic approach of BFLOC was relatively robust.

  3. Identification of a Novel Group of Bacteria in Sludge from a Deteriorated Biological Phosphorus Removal Reactor

    PubMed Central

    Nielsen, Alex T.; Liu, Wen-Tso; Filipe, Carlos; Grady, Leslie; Molin, Søren; Stahl, David A.

    1999-01-01

    The microbial diversity of a deteriorated biological phosphorus removal reactor was investigated by methods not requiring direct cultivation. The reactor was fed with media containing acetate and high levels of phosphate (P/C weight ratio, 8:100) but failed to completely remove phosphate in the effluent and showed very limited biological phosphorus removal activity. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S ribosomal DNA was used to investigate the bacterial diversity. Up to 11 DGGE bands representing at least 11 different sequence types were observed; DNA from the 6 most dominant of these bands was further isolated and sequenced. Comparative phylogenetic analysis of the partial 16S rRNA sequences suggested that one sequence type was affiliated with the alpha subclass of the Proteobacteria, one was associated with the Legionella group of the gamma subclass of the Proteobacteria, and the remaining four formed a novel group of the gamma subclass of the Proteobacteria with no close relationship to any previously described species. The novel group represented approximately 75% of the PCR-amplified DNA, based on the DGGE band intensities. Two oligonucleotide rRNA probes for this novel group were designed and used in a whole-cell hybridization analysis to investigate the abundance of this novel group in situ. The bacteria were coccoid and 3 to 4 μm in diameter and represented approximately 35% of the total population, suggesting a relatively close agreement with the results obtained by the PCR-based DGGE method. Further, based on electron microscopy and standard staining microscopic analysis, this novel group was able to accumulate granule inclusions, possibly consisting of polyhydroxyalkanoate, inside the cells. PMID:10049891

  4. BIOLOGICAL NITRIFICATION IN A FULL-SCALE AND PILOT-SCALE IRON REMOVAL DRINKING WATER TREATMENT PLANT

    EPA Science Inventory

    Ammonia in source waters can cause water treatment and distribution system problems, many of which are associated with biological nitrification. Therefore, in some cases, the removal of ammonia from water is desirable. Biological oxidation of ammonia to nitrite and nitrate (nitr...

  5. Impact of salinity on organic matter and nitrogen removal from a municipal wastewater RO concentrate using biologically activated carbon coupled with UV/H2O2.

    PubMed

    Pradhan, Shovana; Fan, Linhua; Roddick, Felicity A; Shahsavari, Esmaeil; Ball, Andrew S

    2016-05-01

    The concentrate streams generated from reverse osmosis (RO)-based municipal wastewater reclamation processes contain organic substances and nutrients at elevated concentrations, posing environmental and health risks on their disposal to confined receiving environments such as bays. The impact of salinity (TDS at 7, 10 and 16 g/L) of a RO concentrate (ROC) on the treatment efficiency of a biological activated carbon (BAC) system after pre-oxidation with UV/H2O2 was characterised in terms of removal of organic matter and nitrogen species, and the bacterial communities. Organic matter removal was comparable for the ROC over the tested salinity range, with 45-49% of DOC and 70-74% of UVA254 removed by the combined treatment. However, removal in total nitrogen (TN) was considerably higher for the ROC at the high salinity (TDS ∼ 16 mg/L) compared with the low (∼7 g/L) and medium salinity (∼10 g/L). Effective nitrification with high ammonium removal (>90%) was achieved at all salinity levels, whereas greater denitrification (39%) was obtained at high salinity than low (23%) and medium salinity (27%) which might suggest that the bacterial communities contributing to the greater denitrification were more halotolerant. Microbiological characterisation using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and culture based techniques showed that diversified bacterial communities were present in the BAC system as evident from different 16S rDNA. The major bacterial groups residing on the BAC media belonged to Bacillus (Firmicutes), Pseudomonas (γ-Proteobacteria), and Rhodococcus (Actinobacteria) for all salinity levels, confirming that these microbial communities could be responsible for carbon and nitrogen removal at the different salinity levels. This has implications in understanding the effectiveness and robustness of the BAC system over the salinity range of the ROC and so would be useful for optimising the treatment efficiency of

  6. Characterization of nutrient removal and microalgal biomass production on an industrial waste-stream by application of the deceleration-stat technique.

    PubMed

    Van Wagenen, Jon; Pape, Mathias Leon; Angelidaki, Irini

    2015-05-15

    Industrial wastewaters can serve as a nutrient and water source for microalgal production. In this study the effluent of an internal circulation (IC) reactor anaerobically treating the wastes of a biotechnology production facility were chosen as the cultivation medium for Chlorella sorokiniana in batch and continuous cultures. The aim was to evaluate the rates of nutrient removal and biomass production possible at various dilution rates. The results demonstrate that the industrial wastewater served as a highly effective microalgae culture medium and that dilution rate strongly influenced algae productivity in a short light-path photobioreactor. Batch culture on undiluted wastewater showed biomass productivity of 1.33 g L(-1)day(-1), while removing over 99% of the ammonia and phosphate from the wastewater. Deceleration-stat (D-stat) experiments performed at high and low intensities of 2100 and 200 (μmol photon m(2)s(-1)) established the optimal dilution rates to reach volumetric productivity of 5.87 and 1.67 g L(-1)day(-1) respectively. The corresponding removal rates of nitrogen were 238 and 93 mg L(-1)day(-1) and 40 and 19 mg L(-1)day(-1) for phosphorous. The yield on photons at low light intensity was as high as had been observed in any previous report indicating that the waste stream allowed the algae to grow at its full potential.

  7. Pilot-scale test of an advanced, integrated wastewater treatment process with sludge reduction, inorganic solids separation, phosphorus recovery, and enhanced nutrient removal (SIPER).

    PubMed

    Yan, Peng; Ji, Fangying; Wang, Jing; Fan, Jianping; Guan, Wei; Chen, Qingkong

    2013-08-01

    Sludge reduction technologies are increasingly important in wastewater treatment, but have some defects. In order to remedy them, a novel, integrated process including sludge reduction, inorganic solids separation, phosphorus recovery, and enhanced nutrient removal was developed. The pilot-scale system was operated steadily at a treatment scale of 10 m(3)/d for 90 days. The results showed excellent nutrient removal, with average removal efficiencies for NH4(+)-N, TN, TP, and COD reaching 98.2 ± 1.34%, 75.5 ± 3.46%, 95.3 ± 1.65%, and 92.7 ± 2.49%, respectively. The ratio of mixed liquor volatile suspended solids (MLVSS) to mixed liquor suspended solids (MLSS) in the system gradually increased, from 0.33 to 0.52. The process effectively prevented the accumulation of inert or inorganic solids in activated sludge. Phosphorus was recovered as a crystalline product with aluminum ion from wastewater. The observed sludge yield Yobs of the system was 0.103 gVSS/g COD, demonstrating that the system's sludge reduction potential is excellent.

  8. Removal of novel antiandrogens identified in biological effluents of domestic wastewater by activated carbon.

    PubMed

    Ma, Dehua; Chen, Lujun; Liu, Rui

    2017-04-10

    Environmental antiandrogenic (AA) contaminants in effluents from wastewater treatment plants have the potential for negative impacts on wildlife and human health. The aim of our study was to identify chemical contaminants with likely AA activity in the biological effluents and evaluate the removal of these antiandrogens (AAs) during advanced treatment comprising adsorption onto granular activated carbon (GAC). In this study, profiling of AA contaminants in biological effluents and tertiary effluents was conducted using effect-directed analysis (EDA) including high performance liquid chromatography (HPLC) fractionation, a recombinant yeast screen containing androgen receptor (YAS), in combination with mass spectrometry analyses. Analysis of a wastewater secondary effluent from a membrane bioreactor revealed complex profiles of AA activity comprising 14 HPLC fractions and simpler profiles of GAC effluents with only 2 to 4 moderately polar HPLC fractions depending on GAC treatment conditions. Gas chromatography-mass spectrometry and ultra-high performance liquid chromatography-nanospray mass spectrometry analyses of AA fractions in the secondary effluent resulted in detection of over 10 chemical contaminants, which showed inhibition of YAS activity and were potential AAs. The putative AAs included biocides, food additives, flame retardants, pharmaceuticals and industrial contaminants. To our knowledge, it is the first time that the AA properties of N-ethyl-2-isopropyl-5-methylcyclohexanecarboxamide (WS3), cetirizine, and oxcarbazepine are reported. The EDA used in this study was proven to be a powerful tool to identify novel chemical structures with AA activity in the complex aquatic environment. The adsorption process to GAC of all the identified antiandrogens, except WS3 and triclosan, fit well with the pseudo-second order kinetics models. Adsorption to GAC could further remove most of the AAs identified in the biological effluents with high efficiencies.

  9. Is biological treatment a viable alternative for micropollutant removal in drinking water treatment processes?

    PubMed

    Benner, Jessica; Helbling, Damian E; Kohler, Hans-Peter E; Wittebol, Janneke; Kaiser, Elena; Prasse, Carsten; Ternes, Thomas A; Albers, Christian N; Aamand, Jens; Horemans, Benjamin; Springael, Dirk; Walravens, Eddy; Boon, Nico

    2013-10-15

    In western societies, clean and safe drinking water is often taken for granted, but there are threats to drinking water resources that should not be underestimated. Contamination of drinking water sources by anthropogenic chemicals is one threat that is particularly widespread in industrialized nations. Recently, a significant amount of attention has been given to the occurrence of micropollutants in the urban water cycle. Micropollutants are bioactive and/or persistent chemicals originating from diverse sources that are frequently detected in water resources in the pg/L to μg/L range. The aim of this review is to critically evaluate the viability of biological treatment processes as a means to remove micropollutants from drinking water resources. We first place the micropollutant problem in context by providing a comprehensive summary of the reported occurrence of micropollutants in raw water used directly for drinking water production and in finished drinking water. We then present a critical discussion on conventional and advanced drinking water treatment processes and their contribution to micropollutant removal. Finally, we propose biological treatment and bioaugmentation as a potential targeted, cost-effective, and sustainable alternative to existing processes while critically examining the technical limitations and scientific challenges that need to be addressed prior to implementation. This review will serve as a valuable source of data and literature for water utilities, water researchers, policy makers, and environmental consultants. Meanwhile this review will open the door to meaningful discussion on the feasibility and application of biological treatment and bioaugmentation in drinking water treatment processes to protect the public from exposure to micropollutants.

  10. Nutrient cycling and soil biology in row crop systems under intensive tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent interest in management of the soil biological component to improve soil health requires a better understanding on how management practices (e.g., tillage) and environmental conditions influence soil organisms. Intensive tillage often results in reduced organic matter content in the surface so...

  11. Occurrence of cyclophosphamide and ifosfamide in aqueous environment and their removal by biological and abiotic wastewater treatment processes.

    PubMed

    Česen, Marjeta; Kosjek, Tina; Laimou-Geraniou, Maria; Kompare, Boris; Širok, Brane; Lambropolou, Dimitra; Heath, Ester

    2015-09-15

    Cytostatic drug residues in the aqueous environment are of concern due to their possible adverse effects on non-target organisms. Here we report the occurrence and removal efficiency of cyclophosphamide (CP) and ifosfamide (IF) by biological and abiotic treatments including advanced oxidation processes (AOPs). Cyclophosphamide was detected in hospital wastewaters (14-22,000 ng L(-1)), wastewater treatment plant influents (19-27 ng L(-1)) and effluent (17 ng L(-1)), whereas IF was detected only in hospital wastewaters (48-6800 ng L(-1)). The highest removal efficiency during biological treatment (attached growth biomass in a flow through bioreactor) was 59 ± 15% and 35 ± 9.3% for CP and IF, respectively. Also reported are the removal efficiencies of both compounds from wastewater using hydrodynamic cavitation (HC), ozonation (O3) and/or UV, either individually or in combination with hydrogen peroxide (H2O2). Hydrodynamic cavitation did not remove CP and IF to any significant degree. The highest removal efficiencies: 99 ± 0.71% for CP and 94 ± 2.4% for IF, were achieved using UV/O3/H2O2 at 5 g L(-1) for 120 min. When combined with biological treatment, removal efficiencies were >99% for both compounds. This is the first report of combined biological and AOP treatment of CP and IF from wastewater with a removal efficiency >99%.

  12. Efficient nitrogen removal via simultaneous nitrification and denitrification in a penicillin wastewater biological treatment plant.

    PubMed

    Luo, Weiwei; Jin, Xibiao; Yu, Yonglian; Zhou, Sichen; Lu, Shuguang

    2014-01-01

    Nitrogen-removal performance was investigated in a penicillin wastewater biological treatment plant (P-WWTP) reconstructed from a cyclic activated sludge system (CASS) tank designed for simultaneous nitrification and denitrification (SND). Good performance was obtained during a 900-day operation period, as indicated by effluent chemical oxygen demand (COD), total nitrogen (TN) and ammonia nitrogen (NH₃‒N) values of 318 ± 34, 28.7 ± 2.4 and<0.2 mg L⁻¹ when the influent COD, total Kjeldahl nitrogen (TKN) and NH₃‒N were 3089 ± 453, 251.4 ± 26.5 and 124.8 ± 26.8 mg L⁻¹, respectively. Nitrification and denitrification occurred at different spaces, that is, 71.4% of TN removal occurred in the first 40% of the aeration tank, while 68.8% of the TKN removal occurred in 40-100% of the aeration tank. Sufficient easily biodegradable organics (EBO) in wastewater were key to the occurrence of SND. The denitrification rate under aeration conditions was 10.7 mg N g VSS⁻¹ h⁻¹ when EBO were sufficient, but 0.98 mg N g VSS⁻¹ h⁻¹ when EBO were completely degraded. Nitrification primarily occurred in the rear of the aeration tank owing to the competition for oxygen between carbonaceous oxidation and nitrification. The nitrification rate was only 7.13 mg NOD g VSS⁻¹ h⁻¹ at the beginning of the reaction, but 14.7 mg NOD g VSS⁻¹ h⁻¹ when EBO were completely degraded. These results will facilitate the improvement of nitrogen removal by existing WWTPs.

  13. Changes in soil carbon and nutrients following 6 years of litter removal and addition in a tropical semi-evergreen rain forest

    NASA Astrophysics Data System (ADS)

    Tanner, Edmund Vincent John; Sheldrake, Merlin W. A.; Turner, Benjamin L.

    2016-11-01

    Increasing atmospheric CO2 and temperature may increase forest productivity, including litterfall, but the consequences for soil organic matter remain poorly understood. To address this, we measured soil carbon and nutrient concentrations at nine depths to 2 m after 6 years of continuous litter removal and litter addition in a semi-evergreen rain forest in Panama. Soils in litter addition plots, compared to litter removal plots, had higher pH and contained greater concentrations of KCl-extractable nitrate (both to 30 cm); Mehlich-III extractable phosphorus and total carbon (both to 20 cm); total nitrogen (to 15 cm); Mehlich-III calcium (to 10 cm); and Mehlich-III magnesium and lower bulk density (both to 5 cm). In contrast, litter manipulation did not affect ammonium, manganese, potassium or zinc, and soils deeper than 30 cm did not differ for any nutrient. Comparison with previous analyses in the experiment indicates that the effect of litter manipulation on nutrient concentrations and the depth to which the effects are significant are increasing with time. To allow for changes in bulk density in calculation of changes in carbon stocks, we standardized total carbon and nitrogen on the basis of a constant mineral mass. For 200 kg m-2 of mineral soil (approximately the upper 20 cm of the profile) about 0.5 kg C m-2 was "missing" from the litter removal plots, with a similar amount accumulated in the litter addition plots. There was an additional 0.4 kg C m-2 extra in the litter standing crop of the litter addition plots compared to the control. This increase in carbon in surface soil and the litter standing crop can be interpreted as a potential partial mitigation of the effects of increasing CO2 concentrations in the atmosphere.

  14. Functionalized Nanoporous Silica for Removal of Heavy Metals from Biological Systems; Adsorption and Application

    SciTech Connect

    Yantasee, Wassana; Rutledge, Ryan D.; Chouyyok, Wilaiwan; Sukwarotwat, Vichaya; Orr, Galya; Warner, Cynthia L.; Warner, Marvin G.; Fryxell, Glen E.; Wiacek, Robert J.; Timchalk, Charles; Addleman, Raymond S.

    2010-10-01

    Functionalized nanoporous silica, often referred to as self-assembled monolayers on mesoporous supports (SAMMS) have previously demonstrated the ability to serve as very effective heavy metal sorbents in a range of aquatic and environmental systems suggesting they may be advantageously utilized for biomedical applications such as chelation therapy. Herein we evaluate surface chemistries for heavy metal capture from biological fluids, various facets of the materials biocompatibility and the suitability of these materials as potential therapeutics. Of the materials tested, thiol-functionalized SAMMS proved most capable of removing selected heavy metals from biological solutions (i.e. blood, urine, etc.) As a result, thiol SAMMS was further analyzed to assess the material’s performance under a number of different biologically relevant conditions (i.e. variable pH and ionic strength) as well to gauge any potentially negative cellular effects resulting from interaction with the sorbent, such as cellular toxicity or possible chelation of essential minerals. Additionally, cellular uptake studies demonstrated no cell membrane permeation by the silica-based materials generally highlighting their ability to remain cellularly inert and thus non-toxic. As a result, it has been determined that organic ligand-functionalized nanoporous silica materials could be a valuable material for detoxification therapeutics and potentially other biomedical applications as needed.

  15. Enhanced Removal of Lead by Chemically and Biologically Treated Carbonaceous Materials

    PubMed Central

    Mahmoud, Mohamed E.; Osman, Maher M.; Ahmed, Somia B.; Abdel-Fattah, Tarek M.

    2012-01-01

    Hybrid sorbents and biosorbents were synthesized via chemical and biological treatment of active carbon by simple and direct redox reaction followed by surface loading of baker's yeast. Surface functionality and morphology of chemically and biologically modified sorbents and biosorbents were studied by Fourier Transform Infrared analysis and scanning electron microscope imaging. Hybrid carbonaceous sorbents and biosorbents were characterized by excellent efficiency and superiority toward lead(II) sorption compared to blank active carbon providing a maximum sorption capacity of lead(II) ion as 500 μmol g−1. Sorption processes of lead(II) by these hybrid materials were investigated under the influence of several controlling parameters such as pH, contact time, mass of sorbent and biosorbent, lead(II) concentration, and foreign ions. Lead(II) sorption mechanisms were found to obey the Langmuir and BET isotherm models. The potential applications of chemically and biologically modified-active carbonaceous materials for removal and extraction of lead from real water matrices were also studied via a double-stage microcolumn technique. The results of this study were found to denote to superior recovery values of lead (95.0–99.0 ± 3.0–5.0%) by various carbonaceous-modified-bakers yeast biosorbents. PMID:22629157

  16. Biofilm establishment and heavy metal removal capacity of an indigenous mining algal-microbial consortium in a photo-rotating biological contactor.

    PubMed

    Orandi, S; Lewis, D M; Moheimani, N R

    2012-09-01

    An indigenous mining algal-microbial consortium was immobilised within a laboratory-scale photo-rotating biological contactor (PRBC) that was used to investigate the potential for heavy metal removal from acid mine drainage (AMD). The microbial consortium, dominated by Ulothrix sp., was collected from the AMD at the Sar Cheshmeh copper mine in Iran. This paper discusses the parameters required to establish an algal-microbial biofilm used for heavy metal removal, including nutrient requirements and rotational speed. The PRBC was tested using synthesised AMD with the multi-ion and acidic composition of wastewater (containing 18 elements, and with a pH of 3.5 ± 0.5), from which the microbial consortium was collected. The biofilm was successfully developed on the PRBC's disc consortium over 60 days of batch-mode operation. The PRBC was then run continuously with a 24 h hydraulic residence time (HRT) over a ten-week period. Water analysis, performed on a weekly basis, demonstrated the ability of the algal-microbial biofilm to remove 20-50 % of the various metals in the order Cu > Ni > Mn > Zn > Sb > Se > Co > Al. These results clearly indicate the significant potential for indigenous AMD microorganisms to be exploited within a PRBC for AMD treatment.

  17. Effects of interspecific competition on the growth of macrophytes and nutrient removal in constructed wetlands: A comparative assessment of free water surface and horizontal subsurface flow systems.

    PubMed

    Zheng, Yucong; Wang, Xiaochang; Dzakpasu, Mawuli; Zhao, Yaqian; Ngo, Huu Hao; Guo, Wenshan; Ge, Yuan; Xiong, Jiaqing

    2016-05-01

    The outcome of competition between adjoining interspecific colonies of Phragmites and Typha in two large field pilot-scale free water surface (FWS) and subsurface flow (SSF) CWs is evaluated. According to findings, the effect of interspecific competition was notable for Phragmites australis, whereby it showed the highest growth performance in both FWS and SSF wetland. In a mixed-culture, P. australis demonstrates superiority in terms of competitive interactions for space between plants. Furthermore, the interspecific competition among planted species seemed to cause different ecological responses of plant species in the two CWs. For example, while relatively high density and shoot height determined the high aboveground dry weight of P. australis in the FWS wetland, this association was not evident in the SSF. Additionally, while plants nutrients uptake accounts for a higher proportion of the nitrogen removal in FWS, that in the SSF accounts for a higher proportion of the phosphorous removal.

  18. Effects of carriers on nutrient removal and membrane fouling in combined process of inclined-plates hydrolytic tank and membrane bioreactor.

    PubMed

    Li, Xin; Liu, Yali; Chu, Mingxing; Liu, Aimin

    2016-11-01

    A novel process, inclined-plates hydrolytic tank (IHT) and membrane bioreactor (MBR), was used to treat domestic sewage continuously. In this study, the effects of carriers' addition on operational performances of IHT-MBR were studied at the hydraulic retention time of 5.4 h and the recycling rate of 200%. Experimental results indicated the removal efficiencies of chemical oxygen demand, total nitrogen and total phosphorus reached 86.8%, 82.9% and 89.6%, respectively, corresponding trans-membrane pressure decreased to 1.50 kPa/d at a packing ratio of 20%. Simultaneously, the scanning electron microscope and soluble microbial products analysis demonstrated that high nutrient removal and low membrane fouling were attributed to the attached growth of microorganisms on carriers. The bioattachment and adsorption of carriers not only decreased the soluble proteins and polysaccharide in MBR, but also provided good living environments for denitrifying bacteria and phosphorus-accumulating bacteria.

  19. Dynamics of intracellular polymers in enhanced biological phosphorus removal processes under different organic carbon concentrations.

    PubMed

    Xing, Lizhen; Ren, Li; Tang, Bo; Wu, Guangxue; Guan, Yuntao

    2013-01-01

    Enhanced biological phosphorus removal (EBPR) may deteriorate or fail during low organic carbon loading periods. Polyphosphate accumulating organisms (PAOs) in EBPR were acclimated under both high and low organic carbon conditions, and then dynamics of polymers in typical cycles, anaerobic conditions with excess organic carbons, and endogenous respiration conditions were examined. After long-term acclimation, it was found that organic loading rates did not affect the yield of PAOs and the applied low organic carbon concentrations were advantageous for the enrichment of PAOs. A low influent organic carbon concentration induced a high production of extracellular carbohydrate. During both anaerobic and aerobic endogenous respirations, when glycogen decreased to around 80 ± 10 mg C per gram of volatile suspended solids, PAOs began to utilize polyphosphate significantly. Regressed by the first-order reaction model, glycogen possessed the highest degradation rate and then was followed by polyphosphate, while biomass decay had the lowest degradation rate.

  20. The effect of free nitrous acid on key anaerobic processes in enhanced biological phosphorus removal systems.

    PubMed

    Ye, Liu; Pijuan, Maite; Yuan, Zhiguo

    2013-02-01

    In this study, the effect of nitrite/FNA on the anaerobic metabolism of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) is investigated. The results clearly show that FNA has a detrimental effect on the acetate uptake rate by both PAOs and GAOs, but this adverse effect is much stronger on PAOs than on GAOs. Also, when FNA was increased, phosphate release to acetate uptake ratio by PAOs increased substantially (250-300% compared to control), which was accompanied by decreases (40-60%) in glycogen degradation and PHA production to VFA uptake. In contrast, these ratios for GAOs remained constant or increased slightly towards the highest FNA concentration applied. These results indicate that the anaerobic metabolism of PAOs is more adversely affected than that of GAOs when FNA is present. This might provide a competitive advantage to GAOs over PAOs in enhanced biological phosphorus removal systems when nitrite is present.

  1. Prediction of intracellular storage polymers using quantitative image analysis in enhanced biological phosphorus removal systems.

    PubMed

    Mesquita, Daniela P; Leal, Cristiano; Cunha, Jorge R; Oehmen, Adrian; Amaral, A Luís; Reis, Maria A M; Ferreira, Eugénio C

    2013-04-03

    The present study focuses on predicting the concentration of intracellular storage polymers in enhanced biological phosphorus removal (EBPR) systems. For that purpose, quantitative image analysis techniques were developed for determining the intracellular concentrations of PHA (PHB and PHV) with Nile blue and glycogen with aniline blue staining. Partial least squares (PLS) were used to predict the standard analytical values of these polymers by the proposed methodology. Identification of the aerobic and anaerobic stages proved to be crucial for improving the assessment of PHA, PHB and PHV intracellular concentrations. Current Nile blue based methodology can be seen as a feasible starting point for further enhancement. Glycogen detection based on the developed aniline blue staining methodology combined with the image analysis data proved to be a promising technique, toward the elimination of the need for analytical off-line measurements.

  2. Simultaneous biological removal of endosulfan (alpha+beta) and nitrates from drinking waters using wheat straw as substrate.

    PubMed

    Aslan, Sükrü; Türkman, Ayşen

    2004-06-01

    Nitrate and endosulfan (alpha+beta) removal was studied in an upflow biological denitrification reactor packed with wheat straw as carbon source and support particles for microorganisms. While almost complete nitrate elimination and between 65% and 70% endosulfan (alpha+beta) elimination occurred when the temperature was higher than 20 degrees C; below that value, nitrate removal efficiency decreased to about 10%. Nitrate, dissolved organic carbon (DOC), and endosulfan (alpha+beta) removal efficiencies decreased considerably at 1500 microg/l endosulfan concentration in the batch experiments. Although a high removal efficiency was observed for endosulfan (alpha+beta) and nitrate in the biological denitrification continuous reactor, the effluent water could not be used for drinking purpose because of the unacceptable levels of endosulfan (alpha+beta), colour and dissolved organic content. During the continuous study, 23.4% of the initial weight of wheat straw was lost and 24 g was consumed per gram of nitrogen removed. The results of the continuous study showed that 21.3% of the endosulfan removal was achieved by adsorption onto the wheat straw and 68.2% of the endosulfan removal occurred by biological activity and the remaining portion was detected in the effluent water.

  3. Effects of Eichhornia crassipes and Ceratophyllum demersum on Soil and Water Environments and Nutrient Removal in Wetland Microcosms.

    PubMed

    Sung, Kijune; Lee, Geun-Joo; Munster, Clyde

    2015-01-01

    Wetland plants are important components that influence the biogeochemistry of wetland ecosystems. Therefore, remediation performance in wetlands can differ depending on the growth forms of plants. In this study, the effects of Eichhornia crassipes (floating plant) and Ceratophyllum demersum (submerged plant) on the wetland soil and water environments were investigated using a microcosm study with simulated hydrology of retention-type wetlands between rainfall events. The C. demersum microcosm (SP) showed the fastest recovery with a diel fluctuation pattern of dissolved oxygen, pH, and oxidation-reduction potential (ORP) from the impacts of nutrient inflow. Moreover, SP exhibited the lowest decrease in sediment ORP, the highest dehydrogenase activity, and more organic forms of nitrogen and phosphorus. E. crassipes microcosms exhibited the lowest water temperature, and efficiently controlled algae. In the presence of plants, the total nitrogen and phosphorus concentrations in water rapidly decreased, and the composition of organic and inorganic nutrient forms was altered along with a decrease in concentration. The results indicate that wetland plants help retain nutrients in the system, but the effects varied based on the wetland plant growth forms.

  4. Enhanced primary sludge sonication by heat insulation to reclaim carbon source for biological phosphorous removal.

    PubMed

    Tian, Qing; Wang, Qi; Zhu, Yanbing; Li, Fang; Zhuang, Lin; Yang, Bo

    2017-01-01

    Ultrasound pretreatment is a potent step to disintegrate primary sludge (PS). The supernatant of sonicated PS is recycled as an alternative carbon source for biological phosphorus removal. In this study, we investigated the role of temperature on PS disintegration during sonication. We found that a temperature of 60°C yielded a dissolution rate of about 2% soluble chemical oxygen demand (SCOD) as compared to 7% SCOD using sonication at the specific energy (SE) of 7359kJ/kg TS. Using the SE of 6000kJ/kg TS with heat insulation during sonication, the SCOD dissolution rate of PS was similar to the result at the SE of 7051kJ/kg TS without heat insulation. Upon treatment with sonication, the PS released low concentrations of Cu and Zn into the supernatant. The phosphorus-accumulating organisms (PAOs) used the supernatant of sonicated PS as the carbon source. Supplementation with the diluted sonicated PS supernatant (SCOD≈1000mg/L) in anaerobic phase resulted in the release of phosphorus (36mg/L) and the production of polyhydroxyalkanoates (PHAs) (0.36g PHA/g SS). Compared with sodium acetate, higher polyhydroxyvalerate (PHV) faction in the polyhydroxyalkanoates (PHAs) was observed in the biomass when incubated with sonicated PS as the carbon source. This work provides a simple pathway to conserve energy and to enhance efficiencies of ultrasonic pretreatment and the recovery of carbon source from the sludge for improving the phosphorus removal in the ENR system.

  5. Exploring the Shift in Structure and Function of Microbial Communities Performing Biological Phosphorus Removal

    PubMed Central

    Mao, Yanping; Wang, Zhiping; Li, Liguan; Jiang, Xiaotao; Zhang, Xuxiang; Ren, Hongqiang; Zhang, Tong

    2016-01-01

    A sequencing batch reactor fed mainly by acetate was operated to perform enhanced biological phosphorus removal (EBPR). A short-term pH shock from 7.0 to 6.0 led to a complete loss of phosphate-removing capability and a drastic change of microbial communities. 16S rRNA gene pyrosequencing showed that large proportions of glycogen accumulating organisms (GAOs) (accounted for 16% of bacteria) bloomed, including Candidatus Competibacter phosphatis and Defluviicoccus-related tetrad-forming organism, causing deteriorated EBPR performance. The EBPR performance recovered with time and the dominant Candidatus Accumulibacter (Accumulibacter) clades shifted from Clade IIC to IIA while GAOs populations shrank significantly. The Accumulibacter population variation provided a good opportunity for genome binning using a bi-dimensional coverage method, and a genome of Accumulibacter Clade IIC was well retrieved with over 90% completeness. Comparative genomic analysis demonstrated that Accumulibacter clades had different abilities in nitrogen metabolism and carbon fixation, which shed light on enriching different Accumulibacter populations selectively. PMID:27547976

  6. Integrative microbial community analysis reveals full-scale enhanced biological phosphorus removal under tropical conditions

    NASA Astrophysics Data System (ADS)

    Law, Yingyu; Kirkegaard, Rasmus Hansen; Cokro, Angel Anisa; Liu, Xianghui; Arumugam, Krithika; Xie, Chao; Stokholm-Bjerregaard, Mikkel; Drautz-Moses, Daniela I.; Nielsen, Per Halkjær; Wuertz, Stefan; Williams, Rohan B. H.

    2016-05-01

    Management of phosphorus discharge from human waste is essential for the control of eutrophication in surface waters. Enhanced biological phosphorus removal (EBPR) is a sustainable, efficient way of removing phosphorus from waste water without employing chemical precipitation, but is assumed unachievable in tropical temperatures due to conditions that favour glycogen accumulating organisms (GAOs) over polyphosphate accumulating organisms (PAOs). Here, we show these assumptions are unfounded by studying comparative community dynamics in a full-scale plant following systematic perturbation of operational conditions, which modified community abundance, function and physicochemical state. A statistically significant increase in the relative abundance of the PAO Accumulibacter was associated with improved EBPR activity. GAO relative abundance also increased, challenging the assumption of competition. An Accumulibacter bin-genome was identified from a whole community metagenomic survey, and comparative analysis against extant Accumulibacter genomes suggests a close relationship to Type II. Analysis of the associated metatranscriptome data revealed that genes encoding proteins involved in the tricarboxylic acid cycle and glycolysis pathways were highly expressed, consistent with metabolic modelling results. Our findings show that tropical EBPR is indeed possible, highlight the translational potential of studying competition dynamics in full-scale waste water communities and carry implications for plant design in tropical regions.

  7. Removal of nitrate and sulphate from biologically treated municipal wastewater by electrocoagulation

    NASA Astrophysics Data System (ADS)

    Sharma, Arun Kumar; Chopra, A. K.

    2015-07-01

    The present investigation observed the effect of current density (j), electrocoagulation (EC) time, inter electrode distance, electrode area, initial pH and settling time on the removal of nitrate (NO3 -) and sulphate (SO4 2-) from biologically treated municipal wastewater (BTMW), and optimization of the operating conditions of the EC process. A glass chamber of two-liter volume was used for the experiments with DC power supply using two electrode plates of aluminum (Al-Al). The maximum removal of NO3 - (63.21 %) and SO4 2- (79.98 %) of BTMW was found with the optimum operating conditions: current density: 2.65 A/m2, EC time: 40 min, inter electrode distance: 0.5 cm, electrode area: 160 cm2, initial pH: 7.5 and settling time: 60 min. The EC brought down the concentration of NO3 - within desirable limit of the Bureau of Indian Standard (BIS)/WHO for drinking water. Under optimal operating conditions, the operating cost was found to be 1.01/m3 of water in terms of the electrode consumption (23.71 × 10-5 kg Al/m3) and energy consumption (101.76 kWh/m3).

  8. Removal of methyl bromide in coastal seawater: Chemical and biological rates

    NASA Astrophysics Data System (ADS)

    King, Daniel B.; Saltzman, Eric S.

    1997-08-01

    A stable isotope tracer technique was used to investigate the loss rate of methyl bromide in surface ocean waters. Unfiltered and 0.2 μm-filtered or autoclaved aliquants of Biscayne Bay seawater samples were spiked with 13CH3Br at roughly 10-100 times ambient concentrations (50-800 pM) and incubated for 10-30 hours. The concentration of 13CH3Br was monitored using gas chromatography with isotope dilution mass spectrometry, with CD3Br as the isotope spike. Removal rates in unfiltered aliquants were significantly faster than in the 0.2 μm-filtered or autoclaved aliquants, indicating that some of the loss of methyl bromide was associated with particulate matter. Filtration experiments indicate that the particulate material responsible for methyl bromide loss is between 0.2 and 1.2 μm in diameter, suggesting that bacteria are likely to be responsible. The particulate-related removal of methyl bromide was inhibited by autoclaving, supporting a biological mechanism.

  9. Methanol-driven enhanced biological phosphorus removal with a syntrophic consortium.

    PubMed

    Tayà, Carlota; Guerrero, Javier; Vanneste, Gianni; Guisasola, Albert; Baeza, Juan A

    2013-02-01

    The presence of suitable carbon sources for enhanced biological phosphorus removal (EBPR) plays a key role in phosphorus removal from wastewater in urban WWTP. For wastewaters with low volatile fatty acids (VFAs) content, an external carbon addition is necessary. As methanol is the most commonly external carbon source used for denitrification it could be a priori a promising alternative, but previous attempts to use it for EBPR have failed. This study is the first successful report of methanol utilization as external carbon source for EBPR. Since a direct replacement strategy (i.e., supply of methanol as a sole carbon source to a propionic-fed PAO-enriched sludge) failed, a novel process was designed and implemented successfully: development of a consortium with anaerobic biomass and polyphosphate accumulating organisms (PAOs). Methanol-degrading acetogens were (i) selected against other anaerobic methanol degraders from an anaerobic sludge; (ii) subjected to conventional EBPR conditions (anaerobic + aerobic); and (iii) bioaugmented with PAOs. EBPR with methanol as a sole carbon source was sustained in a mid-term basis with this procedure.

  10. Integrative microbial community analysis reveals full-scale enhanced biological phosphorus removal under tropical conditions

    PubMed Central

    Law, Yingyu; Kirkegaard, Rasmus Hansen; Cokro, Angel Anisa; Liu, Xianghui; Arumugam, Krithika; Xie, Chao; Stokholm-Bjerregaard, Mikkel; Drautz-Moses, Daniela I.; Nielsen, Per Halkjær; Wuertz, Stefan; Williams, Rohan B. H.

    2016-01-01

    Management of phosphorus discharge from human waste is essential for the control of eutrophication in surface waters. Enhanced biological phosphorus removal (EBPR) is a sustainable, efficient way of removing phosphorus from waste water without employing chemical precipitation, but is assumed unachievable in tropical temperatures due to conditions that favour glycogen accumulating organisms (GAOs) over polyphosphate accumulating organisms (PAOs). Here, we show these assumptions are unfounded by studying comparative community dynamics in a full-scale plant following systematic perturbation of operational conditions, which modified community abundance, function and physicochemical state. A statistically significant increase in the relative abundance of the PAO Accumulibacter was associated with improved EBPR activity. GAO relative abundance also increased, challenging the assumption of competition. An Accumulibacter bin-genome was identified from a whole community metagenomic survey, and comparative analysis against extant Accumulibacter genomes suggests a close relationship to Type II. Analysis of the associated metatranscriptome data revealed that genes encoding proteins involved in the tricarboxylic acid cycle and glycolysis pathways were highly expressed, consistent with metabolic modelling results. Our findings show that tropical EBPR is indeed possible, highlight the translational potential of studying competition dynamics in full-scale waste water communities and carry implications for plant design in tropical regions. PMID:27193869

  11. Exploring the Shift in Structure and Function of Microbial Communities Performing Biological Phosphorus Removal.

    PubMed

    Mao, Yanping; Wang, Zhiping; Li, Liguan; Jiang, Xiaotao; Zhang, Xuxiang; Ren, Hongqiang; Zhang, Tong

    2016-01-01

    A sequencing batch reactor fed mainly by acetate was operated to perform enhanced biological phosphorus removal (EBPR). A short-term pH shock from 7.0 to 6.0 led to a complete loss of phosphate-removing capability and a drastic change of microbial communities. 16S rRNA gene pyrosequencing showed that large proportions of glycogen accumulating organisms (GAOs) (accounted for 16% of bacteria) bloomed, including Candidatus Competibacter phosphatis and Defluviicoccus-related tetrad-forming organism, causing deteriorated EBPR performance. The EBPR performance recovered with time and the dominant Candidatus Accumulibacter (Accumulibacter) clades shifted from Clade IIC to IIA while GAOs populations shrank significantly. The Accumulibacter population variation provided a good opportunity for genome binning using a bi-dimensional coverage method, and a genome of Accumulibacter Clade IIC was well retrieved with over 90% completeness. Comparative genomic analysis demonstrated that Accumulibacter clades had different abilities in nitrogen metabolism and carbon fixation, which shed light on enriching different Accumulibacter populations selectively.

  12. Optimization of a full-scale Unitank wastewater treatment plant for biological phosphorus removal.

    PubMed

    Zhou, Zhen; Xing, Can; Wu, Zhichao; Tong, Fei; Wang, Junru

    2014-01-01

    The Unitank process combines the advantages of traditional continuous-flow activated sludge processes and sequencing batch reactors, and has been extensively employed in many wastewater treatment plants (WWTPs) in China. Biological phosphorus removal (BPR) of a full-scale Unitank WWTP was optimized by increasing anaerobic time from 80 to 120 min in an operation cycle of 360 min and reducing solid retention time (SRT) from 21.3 to 13.1 d. The BPR efficiency of the full-scale Unitank system increased from 63.8% (SRT of 21.3 d) to 83.2% for a SRT of 13.1 d. When the anaerobic time increased from 80 to 120 min, the net anaerobic phosphorus release amount increased from 0.25 to 1.06 mg L(-1), and sludge phosphorus content rose from 13.8 to 15.0 mgP x (gSS)(-1). During half an operation cycle, the average specific phosphorus release rate increased from 0.097mgP x (gVSS x h)(-1) in 0-40 min to 0.825 mgP x (gVSS x h)(-1) in 40-60 min. Reducing SRT and increasing anaerobic time account for 84.6% and 15.4% in the total increment of phosphorus removal of 1.15 mgL(-1).

  13. Metabolic versatility in full-scale wastewater treatment plants performing enhanced biological phosphorus removal.

    PubMed

    Lanham, Ana B; Oehmen, Adrian; Saunders, Aaron M; Carvalho, Gilda; Nielsen, Per H; Reis, Maria A M

    2013-12-01

    This study analysed the enhanced biological phosphorus removal (EBPR) microbial community and metabolic performance of five full-scale EBPR systems by using fluorescence in situ hybridisation combined with off-line batch tests fed with acetate under anaerobic-aerobic conditions. The phosphorus accumulating organisms (PAOs) in all systems were stable and showed little variability between each plant, while glycogen accumulating organisms (GAOs) were present in two of the plants. The metabolic activity of each sludge showed the frequent involvement of the anaerobic tricarboxylic acid cycle (TCA) in PAO metabolism for the anaerobic generation of reducing equivalents, in addition to the more frequently reported glycolysis pathway. Metabolic variability in the use of the two pathways was also observed, between different systems and in the same system over time. The metabolic dynamics was linked to the availability of glycogen, where a higher utilisation of the glycolysis pathway was observed in the two systems employing side-stream hydrolysis, and the TCA cycle was more active in the A(2)O systems. Full-scale plants that showed higher glycolysis activity also exhibited superior P removal performance, suggesting that promotion of the glycolysis pathway over the TCA cycle could be beneficial towards the optimisation of EBPR systems.

  14. Integrative microbial community analysis reveals full-scale enhanced biological phosphorus removal under tropical conditions.

    PubMed

    Law, Yingyu; Kirkegaard, Rasmus Hansen; Cokro, Angel Anisa; Liu, Xianghui; Arumugam, Krithika; Xie, Chao; Stokholm-Bjerregaard, Mikkel; Drautz-Moses, Daniela I; Nielsen, Per Halkjær; Wuertz, Stefan; Williams, Rohan B H

    2016-05-19

    Management of phosphorus discharge from human waste is essential for the control of eutrophication in surface waters. Enhanced biological phosphorus removal (EBPR) is a sustainable, efficient way of removing phosphorus from waste water without employing chemical precipitation, but is assumed unachievable in tropical temperatures due to conditions that favour glycogen accumulating organisms (GAOs) over polyphosphate accumulating organisms (PAOs). Here, we show these assumptions are unfounded by studying comparative community dynamics in a full-scale plant following systematic perturbation of operational conditions, which modified community abundance, function and physicochemical state. A statistically significant increase in the relative abundance of the PAO Accumulibacter was associated with improved EBPR activity. GAO relative abundance also increased, challenging the assumption of competition. An Accumulibacter bin-genome was identified from a whole community metagenomic survey, and comparative analysis against extant Accumulibacter genomes suggests a close relationship to Type II. Analysis of the associated metatranscriptome data revealed that genes encoding proteins involved in the tricarboxylic acid cycle and glycolysis pathways were highly expressed, consistent with metabolic modelling results. Our findings show that tropical EBPR is indeed possible, highlight the translational potential of studying competition dynamics in full-scale waste water communities and carry implications for plant design in tropical regions.

  15. Rare taxa have potential to make metabolic contributions in enhanced biological phosphorus removal ecosystems.

    PubMed

    Lawson, Christopher E; Strachan, Blake J; Hanson, Niels W; Hahn, Aria S; Hall, Eric R; Rabinowitz, Barry; Mavinic, Donald S; Ramey, William D; Hallam, Steven J

    2015-12-01

    Enhanced biological phosphorus removal (EBPR) relies on diverse but specialized microbial communities to mediate the cycling and ultimate removal of phosphorus from municipal wastewaters. However, little is known about microbial activity and dynamics in relation to process fluctuations in EBPR ecosystems. Here, we monitored temporal changes in microbial community structure and potential activity across each bioreactor zone in a pilot-scale EBPR treatment plant by examining the ratio of small subunit ribosomal RNA (SSU rRNA) to SSU rRNA gene (rDNA) over a 120 day study period. Although the majority of operational taxonomic units (OTUs) in the EBPR ecosystem were rare, many maintained high potential activities based on SSU rRNA : rDNA ratios, suggesting that rare OTUs contribute substantially to protein synthesis potential in EBPR ecosystems. Few significant differences in OTU abundance and activity were observed between bioreactor redox zones, although differences in temporal activity were observed among phylogenetically cohesive OTUs. Moreover, observed temporal activity patterns could not be explained by measured process parameters, suggesting that other ecological drivers, such as grazing or viral lysis, modulated community interactions. Taken together, these results point towards complex interactions selected for within the EBPR ecosystem and highlight a previously unrecognized functional potential among low abundance microorganisms in engineered ecosystems.

  16. Lead removal and toxicity reduction from industrial wastewater through biological sulfate reduction process.

    PubMed

    Teekayuttasakul, Paphungkorn; Annachhatre, Ajit P

    2008-10-01

    The practicability of lead removal from sulfate-rich wastewater through biological sulfate reduction process with hydrogen as electron donor was investigated. Sulfide, which was converted from sulfate by a sulfate-reducing bacteria (SRB) in a gas-lift reactor, was used to remove lead as lead sulfide precipitate. Furthermore, the toxicity of wastewater in terms of whole effluent toxicity (WET) before and after treatment was analyzed by using Microtox analyzer. The experiment was divided into three stages as follows: Stage I, startup and operation of sulfidogenic process fed with synthetic wastewater in a gas-lift reactor; Stage II, operation of sulfidogenic process fed with real wastewater in the same reactor and analysis of toxicity; and Stage III, separation of lead from wastewater. In stage I, the volumetric sulfate-sulfur loading rate was gradually increased from 1.0 g/L.d until no improvement of sulfide-sulfur production efficiency was evident at 2.58 g/L.d and maximum sulfide-sulfur concentration was set to 340 mg/L. In stage II, the results showed that the laboratory scale reactor could treat a real wastewater without inhibition or any remarkable problem. The produced sulfide-sulfur, 200 mg/L, was a little less in comparison with that of the previous stage. It could be due to the higher concentration of total dissolved solid (TDS). However, the sulfate concentration was still reduced by approximately 30%. The WET test by Microtox showed that toxicity was reduced more than 13 times. In stage III, the effluent from the reactor containing sulfide-sulfur of about 200 mg/L and lead-containing solution of 20 mg/L were fed with sulfide to lead ratio 3 moles: 1 mole into the precipitation chamber in which the optimum pH for lead sulfide precipitation of 8.0 was maintained. It was found that lead removal of 99% was attained.

  17. A metagenome of a full-scale microbial community carrying out enhanced biological phosphorus removal

    PubMed Central

    Albertsen, Mads; Hansen, Lea Benedicte Skov; Saunders, Aaron Marc; Nielsen, Per Halkjær; Nielsen, Kåre Lehmann

    2012-01-01

    Enhanced biological phosphorus removal (EBPR) is widely used for removal of phosphorus from wastewater. In this study, a metagenome (18.2 Gb) was generated using Illumina sequencing from a full-scale EBPR plant to study the community structure and genetic potential. Quantitative fluorescence in situ hybridization (qFISH) was applied as an independent method to evaluate the community structure. The results were in qualitative agreement, but a DNA extraction bias against gram positive bacteria using standard extraction protocols was identified, which would not have been identified without the use of qFISH. The genetic potential for community function showed enrichment of genes involved in phosphate metabolism and biofilm formation, reflecting the selective pressure of the EBPR process. Most contigs in the assembled metagenome had low similarity to genes from currently sequenced genomes, underlining the need for more reference genomes of key EBPR species. Only the genome of ‘Candidatus Accumulibacter', a genus of phosphorus-removing organisms, was closely enough related to the species present in the metagenome to allow for detailed investigations. Accumulibacter accounted for only 4.8% of all bacteria by qFISH, but the depth of sequencing enabled detailed insight into their microdiversity in the full-scale plant. Only 15% of the reads matching Accumulibacter had a high similarity (>95%) to the sequenced Accumulibacter clade IIA strain UW-1 genome, indicating the presence of some microdiversity. The differences in gene complement between the Accumulibacter clades were limited to genes for extracellular polymeric substances and phage-related genes, suggesting a selective pressure from phages on the Accumulibacter diversity. PMID:22170425

  18. A metagenome of a full-scale microbial community carrying out enhanced biological phosphorus removal.

    PubMed

    Albertsen, Mads; Hansen, Lea Benedicte Skov; Saunders, Aaron Marc; Nielsen, Per Halkjær; Nielsen, Kåre Lehmann

    2012-06-01

    Enhanced biological phosphorus removal (EBPR) is widely used for removal of phosphorus from wastewater. In this study, a metagenome (18.2 Gb) was generated using Illumina sequencing from a full-scale EBPR plant to study the community structure and genetic potential. Quantitative fluorescence in situ hybridization (qFISH) was applied as an independent method to evaluate the community structure. The results were in qualitative agreement, but a DNA extraction bias against gram positive bacteria using standard extraction protocols was identified, which would not have been identified without the use of qFISH. The genetic potential for community function showed enrichment of genes involved in phosphate metabolism and biofilm formation, reflecting the selective pressure of the EBPR process. Most contigs in the assembled metagenome had low similarity to genes from currently sequenced genomes, underlining the need for more reference genomes of key EBPR species. Only the genome of 'Candidatus Accumulibacter', a genus of phosphorus-removing organisms, was closely enough related to the species present in the metagenome to allow for detailed investigations. Accumulibacter accounted for only 4.8% of all bacteria by qFISH, but the depth of sequencing enabled detailed insight into their microdiversity in the full-scale plant. Only 15% of the reads matching Accumulibacter had a high similarity (>95%) to the sequenced Accumulibacter clade IIA strain UW-1 genome, indicating the presence of some microdiversity. The differences in gene complement between the Accumulibacter clades were limited to genes for extracellular polymeric substances and phage-related genes, suggesting a selective pressure from phages on the Accumulibacter diversity.

  19. A new biological phosphorus removal process in association with sulfur cycle.

    PubMed

    Wu, Di; Ekama, George A; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2013-06-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production. This study seeks to expand the SANI process into an enhanced biological phosphorus removal (EBPR) process. A sulfur cycle associated EBPR was explored in an alternating anaerobic/oxygen-limited aerobic sequencing batch reactor with acetate fed as sole electron donor and sulfate as sulfur source at a total organic carbon to sulfur ratio of 1.1-3.1 (mg C/mg S). Phosphate uptake and polyphosphate formation was observed in this reactor that sustained high phosphate removal (20 mg P/L removed with 320 mg COD/L). This new EBPR process was supported by six observations: 1) anaerobic phosphate release associated with acetate uptake, poly-phosphate hydrolysis, poly-hydroxyalkanoate (PHA) (and poly-S(2-)/S(0)) formation and an "aerobic" phosphate uptake associated with PHA (and poly-S(2-)/S(0)) degradation, and polyphosphate formation; 2) a high P/VSS ratio (>0.16 mg P/mg VSS) and an associated low VSS/TSS ratio (0.75) characteristic of conventional PAOs; 3) a lack of P-release and P-uptake with formaldehyde inactivation and autoclaved sterilized biomass; 4) an absence of chemical precipitated P crystals as determined by XRD analysis; 5) a sludge P of more than 90% polyphosphate as determined by sequential P extraction; and 6) microscopically, observed PHA, poly-P and S globules in the biomass.

  20. 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

    2017-03-14

    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.

  1. Large-scale utilization of water hyacinth for nutrient removal in Lake Dianchi in China: the effects on the water quality, macrozoobenthos and zooplankton.

    PubMed

    Wang, Zhi; Zhang, Zhiyong; Zhang, Junqian; Zhang, Yingying; Liu, Haiqing; Yan, Shaohua

    2012-11-01

    An ecological engineering project using water hyacinth for nutrient removal was performed in Baishan Bay of a large shallow eutrophic lake, Lake Dianchi in China. In the present study, a systematic survey of water quality, macrozoobenthos and zooplankton inside (IWH), around (AWH) and far away (FWH) water hyacinth mats was conducted in Baishan Bay from August to October 2010. The results showed that the water quality significantly improved at AWH area. Concentrations of nitrogen and phosphorus were lower and transparency was higher at AWH area than those in IWH and FWH areas. Total densities, dominant species densities, and biodiversity indexes of macrozoobenthos and cladocerans as well as copepods did not differ (P>0.05) among each other in all three areas. It was significantly (P<0.05) different for those of rotifers at IWH area compared to those in AWH and FWH areas. The results might suggest a tremendous potential for the utilization of water hyacinth in the eutrophic lake like Lake Dianchi for nutrients removal.

  2. Removing constraints on the biomass production of freshwater macroalgae by manipulating water exchange to manage nutrient flux.

    PubMed

    Cole, Andrew J; de Nys, Rocky; Paul, Nicholas A

    2014-01-01

    Freshwater macroalgae represent a largely overlooked group of phototrophic organisms that could play an important role within an industrial ecology context in both utilising waste nutrients and water and supplying biomass for animal feeds and renewable chemicals and fuels. This study used water from the intensive aquaculture of freshwater fish (Barramundi) to examine how the biomass production rate and protein content of the freshwater macroalga Oedogonium responds to increasing the flux of nutrients and carbon, by either increasing water exchange rates or through the addition of supplementary nitrogen and CO2. Biomass production rates were highest at low flow rates (0.1-1 vol.day-1) using raw pond water. The addition of CO2 to cultures increased biomass production rates by between 2 and 25% with this effect strongest at low water exchange rates. Paradoxically, the addition of nitrogen to cultures decreased productivity, especially at low water exchange rates. The optimal culture of Oedogonium occurred at flow rates of between 0.5-1 vol.day-1, where uptake rates peaked at 1.09 g.m-2.day-1 for nitrogen and 0.13 g.m-2.day-1 for phosphorous. At these flow rates Oedogonium biomass had uptake efficiencies of 75.2% for nitrogen and 22.1% for phosphorous. In this study a nitrogen flux of 1.45 g.m-2.day-1 and a phosphorous flux of 0.6 g.m-2.day-1 was the minimum required to maintain the growth of Oedogonium at 16-17 g DW.m-2.day-1 and a crude protein content of 25%. A simple model of minimum inputs shows that for every gram of dry weight biomass production (g DW.m-2.day-1), Oedogonium requires 0.09 g.m-2.day-1 of nitrogen and 0.04 g.m-2.day-1 of phosphorous to maintain growth without nutrient limitation whilst simultaneously maintaining a high-nutrient uptake rate and efficiency. As such the integrated culture of freshwater macroalgae with aquaculture for the purposes of nutrient recovery is a feasible solution for the bioremediation of wastewater and the supply of a

  3. Removing Constraints on the Biomass Production of Freshwater Macroalgae by Manipulating Water Exchange to Manage Nutrient Flux

    PubMed Central

    Cole, Andrew J.; de Nys, Rocky; Paul, Nicholas A.

    2014-01-01

    Freshwater macroalgae represent a largely overlooked group of phototrophic organisms that could play an important role within an industrial ecology context in both utilising waste nutrients and water and supplying biomass for animal feeds and renewable chemicals and fuels. This study used water from the intensive aquaculture of freshwater fish (Barramundi) to examine how the biomass production rate and protein content of the freshwater macroalga Oedogonium responds to increasing the flux of nutrients and carbon, by either increasing water exchange rates or through the addition of supplementary nitrogen and CO2. Biomass production rates were highest at low flow rates (0.1–1 vol.day−1) using raw pond water. The addition of CO2 to cultures increased biomass production rates by between 2 and 25% with this effect strongest at low water exchange rates. Paradoxically, the addition of nitrogen to cultures decreased productivity, especially at low water exchange rates. The optimal culture of Oedogonium occurred at flow rates of between 0.5–1 vol.day−1, where uptake rates peaked at 1.09 g.m−2.day−1 for nitrogen and 0.13 g.m−2.day−1 for phosphorous. At these flow rates Oedogonium biomass had uptake efficiencies of 75.2% for nitrogen and 22.1% for phosphorous. In this study a nitrogen flux of 1.45 g.m−2.day−1 and a phosphorous flux of 0.6 g.m−2.day−1 was the minimum required to maintain the growth of Oedogonium at 16–17 g DW.m−2.day−1 and a crude protein content of 25%. A simple model of minimum inputs shows that for every gram of dry weight biomass production (g DW.m−2.day−1), Oedogonium requires 0.09 g.m−2.day−1 of nitrogen and 0.04 g.m−2.day−1 of phosphorous to maintain growth without nutrient limitation whilst simultaneously maintaining a high-nutrient uptake rate and efficiency. As such the integrated culture of freshwater macroalgae with aquaculture for the purposes of nutrient recovery is a feasible solution for the

  4. Is anaerobic digestion effective for the removal of organic micropollutants and biological activities from sewage sludge?

    PubMed

    Gonzalez-Gil, L; Papa, M; Feretti, D; Ceretti, E; Mazzoleni, G; Steimberg, N; Pedrazzani, R; Bertanza, G; Lema, J M; Carballa, M

    2016-10-01

    The occurrence of emerging organic micropollutants (OMPs) in sewage sludge has been widely reported; nevertheless, their fate during sludge treatment remains unclear. The objective of this work was to study the fate of OMPs during mesophilic and thermophilic anaerobic digestion (AD), the most common processes used for sludge stabilization, by using raw sewage sludge without spiking OMPs. Moreover, the results of analytical chemistry were complemented with biological assays in order to verify the possible adverse effects (estrogenic and genotoxic) on the environment and human health in view of an agricultural (re)use of digested sludge. Musk fragrances (AHTN, HHCB), ibuprofen (IBP) and triclosan (TCS) were the most abundant compounds detected in sewage sludge. In general, the efficiency of the AD process was not dependent on operational parameters but compound-specific: some OMPs were highly biotransformed (e.g. sulfamethoxazole and naproxen), while others were only slightly affected (e.g. IBP and TCS) or even unaltered (e.g. AHTN and HHCB). The MCF-7 assay evidenced that estrogenicity removal was driven by temperature. The Ames test did not show point mutation in Salmonella typhimurium while the Comet test exhibited a genotoxic effect on human leukocytes attenuated by AD. This study highlights the importance of combining chemical analysis and biological activities in order to establish appropriate operational strategies for a safer disposal of sewage sludge. Actually, it was demonstrated that temperature has an insignificant effect on the disappearance of the parent compounds while it is crucial to decrease estrogenicity.

  5. Fate and behaviour of copper and zinc in secondary biological wastewater treatment processes: II. Removal at varying sludge age.

    PubMed

    Santos, A; Barton, P; Cartmell, E; Coulon, F; Crane, R S; Hillis, P; Lester, J N; Stephenson, T; Judd, S J

    2010-06-01

    The mechanisms for the removal of heavy metals during secondary biological treatment of wastewater, with particular emphasis on the activated sludge process, are considered. It is concluded that the predominant mechanism is the entrapment and co-settlement of insoluble metal species in the mixed liquor (biomass). Secondary extracellular polymeric materials, particularly extracellular polysaccharides and other capsule-forming materials, may also play a role. In general, removal of both copper and zinc was superior at the higher sludge ages employed in this study, 4.3 and 8 days, and can in part be attributed to the superior removals of both biochemical oxygen demand and effluent suspended solids achieved at these sludge ages compared with the lowest sludge age studied, 3.6 days. For both copper and zinc there is an increase in soluble metal across the activated sludge process. However, significant removal of both metals occurs as a consequence of the removal of substantial amounts of insoluble metal. The presence of returned sludge liquors, high in settleable solids, to the mixed liquor appears to moderately enhance the percentage removal of copper and zinc. Membranes used in place of secondary sedimentation also enhance removal of both metals by reducing effluent suspended solids. It is concluded that there is potential for maximizing metal removal by optimization of secondary biological treatment in a sustainable manner, without recourse to energy-intensive or chemically-dependent tertiary treatment technologies.

  6. Evaluation of Simultaneous Nutrient and COD Removal with Polyhydroxybutyrate (PHB) Accumulation Using Mixed Microbial Consortia under Anoxic Condition and Their Bioinformatics Analysis

    PubMed Central

    Jena, Jyotsnarani; Kumar, Ravindra; Dixit, Anshuman; Pandey, Sony; Das, Trupti

    2015-01-01

    Simultaneous nitrate-N, phosphate and COD removal was evaluated from synthetic waste water using mixed microbial consortia in an anoxic environment under various initial carbon load (ICL) in a batch scale reactor system. Within 6 hours of incubation, enriched DNPAOs (Denitrifying Polyphosphate Accumulating Microorganisms) were able to remove maximum COD (87%) at 2g/L of ICL whereas maximum nitrate-N (97%) and phosphate (87%) removal along with PHB accumulation (49 mg/L) was achieved at 8 g/L of ICL. Exhaustion of nitrate-N, beyond 6 hours of incubation, had a detrimental effect on COD and phosphate removal rate. Fresh supply of nitrate-N to the reaction medium, beyond 6 hours, helped revive the removal rates of both COD and phosphate. Therefore, it was apparent that in spite of a high carbon load, maximum COD and nutrient removal can be maintained, with adequate nitrate-N availability. Denitrifying condition in the medium was evident from an increasing pH trend. PHB accumulation by the mixed culture was directly proportional to ICL; however the time taken for accumulation at higher ICL was more. Unlike conventional EBPR, PHB depletion did not support phosphate accumulation in this case. The unique aspect of all the batch studies were PHB accumulation was observed along with phosphate uptake and nitrate reduction under anoxic conditions. Bioinformatics analysis followed by pyrosequencing of the mixed culture DNA from the seed sludge revealed the dominance of denitrifying population, such as Corynebacterium, Rhodocyclus and Paraccocus (Alphaproteobacteria and Betaproteobacteria). Rarefaction curve indicated complete bacterial population and corresponding number of OTUs through sequence analysis. Chao1 and Shannon index (H’) was used to study the diversity of sampling. “UCI95” and “LCI95” indicated 95% confidence level of upper and lower values of Chao1 for each distance. Values of Chao1 index supported the results of rarefaction curve. PMID:25689047

  7. Evaluation of simultaneous nutrient and COD removal with polyhydroxybutyrate (PHB) accumulation using mixed microbial consortia under anoxic condition and their bioinformatics analysis.

    PubMed

    Jena, Jyotsnarani; Kumar, Ravindra; Dixit, Anshuman; Pandey, Sony; Das, Trupti

    2015-01-01

    Simultaneous nitrate-N, phosphate and COD removal was evaluated from synthetic waste water using mixed microbial consortia in an anoxic environment under various initial carbon load (ICL) in a batch scale reactor system. Within 6 hours of incubation, enriched DNPAOs (Denitrifying Polyphosphate Accumulating Microorganisms) were able to remove maximum COD (87%) at 2 g/L of ICL whereas maximum nitrate-N (97%) and phosphate (87%) removal along with PHB accumulation (49 mg/L) was achieved at 8 g/L of ICL. Exhaustion of nitrate-N, beyond 6 hours of incubation, had a detrimental effect on COD and phosphate removal rate. Fresh supply of nitrate-N to the reaction medium, beyond 6 hours, helped revive the removal rates of both COD and phosphate. Therefore, it was apparent that in spite of a high carbon load, maximum COD and nutrient removal can be maintained, with adequate nitrate-N availability. Denitrifying condition in the medium was evident from an increasing pH trend. PHB accumulation by the mixed culture was directly proportional to ICL; however the time taken for accumulation at higher ICL was more. Unlike conventional EBPR, PHB depletion did not support phosphate accumulation in this case. The unique aspect of all the batch studies were PHB accumulation was observed along with phosphate uptake and nitrate reduction under anoxic conditions. Bioinformatics analysis followed by pyrosequencing of the mixed culture DNA from the seed sludge revealed the dominance of denitrifying population, such as Corynebacterium, Rhodocyclus and Paraccocus (Alphaproteobacteria and Betaproteobacteria). Rarefaction curve indicated complete bacterial population and corresponding number of OTUs through sequence analysis. Chao1 and Shannon index (H') was used to study the diversity of sampling. "UCI95" and "LCI95" indicated 95% confidence level of upper and lower values of Chao1 for each distance. Values of Chao1 index supported the results of rarefaction curve.

  8. COD, nutrient removal and disinfection efficiency of a combined subsurface and surface flow constructed wetland: A case study.

    PubMed

    Sartori, Laura; Canobbio, Sergio; Fornaroli, Riccardo; Cabrini, Riccardo; Marazzi, Francesca; Mezzanotte, Valeria

    2016-01-01

    A constructed wetland system composed of a subsurface flow wetland, a surface flow wetland and a facultative pond was studied from July 2008 until May 2012. It was created to treat the domestic sewage produced by a hamlet of 150 inhabitants. Monthly physicochemical and microbiological analyses were carried out in order to evaluate the removal efficiency of each stage of the process and of the total treatment system. Pair-wise Student's t-tests showed that the mean removal of each considered parameter was significantly different (α = 0.05) between the various treatment phases. Two-way ANOVA and Tukey's HSD tests were used to find significant differences between wetland types and seasons in the removal efficiency of the considered water quality parameters. Significant differences in percent removal efficiency between the treatment phases were observed for total phosphorus, total nitrogen, ammonia nitrogen and organic load (expressed as Chemical Oxygen Demand). In general, the wastewater treatment was carried by the sub-superficial flow phase mainly, both in growing season and in quiescence season. Escherichia coli removal ranged from 98% in quiescence season to >99% in growing season (approximately 2-3 orders of magnitude). The inactivation of fecal bacteria was not influenced by the season, but only by the treatment phase.

  9. 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

  10. Growth and nutrient removal in free and immobilized green algae in batch and semi-continuous cultures treating real wastewater.

    PubMed

    Ruiz-Marin, Alejandro; Mendoza-Espinosa, Leopoldo G; Stephenson, Tom

    2010-01-01

    Two species of microalgae growing as immobilized and free-cells were compared to test its ability to remove N and P in batch cultures of urban wastewater. The best microalgae-cell growth configuration was selected to be tested in bioreactor operated in semi-continuous mode. Scenedesmus obliquus showed a higher N and P uptake rate in urban wastewater than Chlorella vulgaris. When tested in semi-continuous mode and with the re-calcification of beads, S. obliquus was more effective in removing N and P for longer periods (181 h) than batch cultures; fecal coliforms removal was good (95%) although the final concentration was still unsuitable for discharge to natural water bodies. Protein and lipids content analysis suggest that, from a practical point of view, immobilized systems could facilitate the separation of the biomass from the treated wastewater although in terms of nutritional value of the biomass, immobilized systems do not represent an advantage over free-cell systems.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

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

    PubMed

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

    2015-05-11

    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.

  13. Seasonal nutrient and plankton dynamics in a physical-biological model of Crater Lake

    USGS Publications Warehouse

    Fennel, K.; Collier, R.; Larson, G.; Crawford, G.; Boss, E.

    2007-01-01

    A coupled 1D physical-biological model of Crater Lake is presented. The model simulates the seasonal evolution of two functional phytoplankton groups, total chlorophyll, and zooplankton in good quantitative agreement with observations from a 10-year monitoring study. During the stratified period in summer and early fall the model displays a marked vertical structure: the phytoplankton biomass of the functional group 1, which represents diatoms and dinoflagellates, has its highest concentration in the upper 40 m; the phytoplankton biomass of group 2, which represents chlorophyta, chrysophyta, cryptomonads and cyanobacteria, has its highest concentrations between 50 and 80 m, and phytoplankton chlorophyll has its maximum at 120 m depth. A similar vertical structure is a reoccurring feature in the available data. In the model the key process allowing a vertical separation between biomass and chlorophyll is photoacclimation. Vertical light attenuation (i.e., water clarity) and the physiological ability of phytoplankton to increase their cellular chlorophyll-to-biomass ratio are ultimately determining the location of the chlorophyll maximum. The location of the particle maxima on the other hand is determined by the balance between growth and losses and occurs where growth and losses equal. The vertical particle flux simulated by our model agrees well with flux measurements from a sediment trap. This motivated us to revisit a previously published study by Dymond et al. (1996). Dymond et al. used a box model to estimate the vertical particle flux and found a discrepancy by a factor 2.5-10 between their model-derived flux and measured fluxes from a sediment trap. Their box model neglected the exchange flux of dissolved and suspended organic matter, which, as our model and available data suggests is significant for the vertical exchange of nitrogen. Adjustment of Dymond et al.'s assumptions to account for dissolved and suspended nitrogen yields a flux estimate that is

  14. Growth and nutrient removal of three macrophytes in response to concentrations and ratios of N and P.

    PubMed

    Liao, JianXiong; Zhang, DeNan; Mallik, Azim; Huang, YuQing; He, ChengXin; Xu, GuangPing

    2017-01-13

    Wastewater from different sources show great differences in concentrations and ratios of N and P. In order to choose suitable plant species to remove excess N and/or P from polluted waters, it is important to know the performances of these plants under different N and P concentrations. In this study, we investigated the growth and N and P removal of three macrophytes, Coix lacryma-jobi, Iris wilsonii and Arundo donax under six N and P combination treatments. C. lacryma-jobi preferred higher N and P concentrations (16 mg N L(-1) and 3.2 mg P L(-1)), and increasing N supply could increase its P removal rate. I. wilsonii exhibited a growth preference at a combination of moderate N and P concentrations (8 mg N L(-1) and 0.8 mg P L(-1)). A. donax could grow well at all combinations of N and P and had significantly higher relative growth rate (RGR) and N and P removal rates than the other two species. These results showed A. donax is a promising species to treat various polluted waters and the other two species can be used specifically to treat certain types of wastewater.

  15. Nutrient removal of a floating plant system receiving low- pollution wastewater: Effects of plant species and influent concentration

    NASA Astrophysics Data System (ADS)

    Duan, J. J.; Zhao, J. N.; Xue, L. H.; Yang, L. Z.

    2016-08-01

    Plant floating bed was adopted in this study to compare the purification effect of four plant species (Oenanthe javanica, Ipomoea aquatica, Hydrocotyle vulgaris, and Iris sibirica) receiving high and low treated domestic sewage. The experiment was conducted for eight months during the low temperature season. The results indicated that the average removal rates of TN and NH4+-N in I. aquatica floating bed were relatively high both under high and low influent concentration during the first stage of the experiment. During the second stage, H. vulgaris showed the best performance for nitrogen treatment, and the average removal rates of TN were 70.7% and 87.7% under high and low influent concentration, while the average removal rates of NH4 +-N were as high as 98.9% and 98.9%, accordingly. Moreover, H. vulgaris contributed most for plant assimilation to nitrogen removal among different plant floating systems. It was also found that the existence of hydrophytes effectively controlled the rise of water pH value and algae growth and reproduction, which helped to improve the aquatic environment. The results provide engineering parameters for the future design of an ecological remediation technology for low-pollution wastewater purification.

  16. Biological nitrogen removal from plating wastewater by submerged membrane bioreactor packed with granular sulfur.

    PubMed

    Moon, Jinyoung; Hwang, Yongwoo; Kim, Junbeum; Kwak, Inho

    Recent toughened water quality standards have necessitated improvements for existing sewer treatment facilities through advanced treatment processes. Therefore, an advanced treatment process that can be installed through simple modification of existing sewer treatment facilities needs to be developed. In this study, a new submerged membrane bioreactor process packed with granular sulfur (MBR-GS) was developed and operated to determine the biological nitrogen removal behaviors of plating wastewater containing a high concentration of NO3(-). Continuous denitrification was carried out at various nitrogen loading rates at 20 °C using synthetic wastewater, which was comprised of NO3(-) and HCO3(-), and actual plating wastewater, which was collected from the effluent water of a plating company called 'H Metals'. High-rate denitrification in synthetic plating wastewater was accomplished at 0.8 kg NO3(-)-N/m(3)·day at a nitrogen loading rate of 0.9 kg NO3(-)-N/m(3)·day. The denitrification rate further increased in actual plating wastewater to 0.91 kg NO3(-)-N/m(3)·day at a nitrogen loading rate of 1.11 kg NO3(-)-N/m(3)·day. Continuous filtration was maintained for up to 30 days without chemical cleaning with a transmembrane pressure in the range of 20 cmHg. Based on stoichiometry, SO4(2-) production and alkalinity consumption could be calculated theoretically. Experimental alkalinity consumption was lower than the theoretical value. This newly proposed MBR-GS process, capable of high-rate nitrogen removal by compulsive flux, is expected to be applicable as an alternative renovation technique for nitrogen treatment of plating wastewater as well as municipal wastewater with a low C/N ratio.

  17. State observers for a biological wastewater nitrogen removal process in a sequential batch reactor.

    PubMed

    Boaventura, K M; Roqueiro, N; Coelho, M A; Araújo, O Q

    2001-08-01

    Biological removal of nitrogen is a two-step process: aerobic autotrophic microorganisms oxidize ammoniacal nitrogen to nitrate, and the nitrate is further reduced to elementary nitrogen by heterotrophic microorganisms under anoxic condition with concomitant organic carbon removal. Several state variables are involved which render process monitoring a demanding task, as in most biotechnological processes, measurement of primary variables such as microorganism, carbon and nitrogen concentrations is either difficult or expensive. An alternative is to use a process model of reduced order for on-line inference of state variables based on secondary process measurements, e.g. pH and redox potential. In this work, two modeling approaches were investigated: a generic reduced order model based on the generally accepted IAWQ No. 1 Model [M. Henze, C.P.L., Grady, W., Gujer, G.V.R., Marais, T., Matsuo, Water Res. 21 (5) (1987) 505-515]-generic model (GM), and a reduced order model specially validated with the data acquired from a benchscale sequential batch reactor (SBR) specific model (SM). Model inaccuracies and measurement errors were compensated for with a Kalman filter structure to develop two state observers: one built with GM, the generic observer (GO), and another based on SM, the specific observer (SO). State variables estimated by GM, SM, GO and SO were compared to experimental data from the SBR unit. GM gave the worst performance while SM predictions presented some model to data mismatch. GO and SO, on the other hand, were both in very good agreement with experimental data showing that filters add robustness against model errors, which reduces the modeling effort while assuring adequate inference of process variables.

  18. Evaluation of the treatment performance of lab-scaled vertical flow constructed wetlands in removal of organic compounds, color and nutrients in azo dye-containing wastewater.

    PubMed

    Dogdu, Gamze; Yalcuk, Arda

    2016-01-01

    The objective of this study is to examine the treatment performance of vertical flow intermittent feeding constructed wetland (VFCW) in removal of organic pollution, nutrients and color in azo-dye containing wastewater. The systems consisted of PVC reactors, some filling materials such as gravel, sand and zeolite and wetland plants including Typha angustifolia and Canna indica. The average treatment efficiency of the systems for COD, color, sulphate, NH4-N, and PO4-P were in the range of 57-63%, 94-99%, 44-48%, 39-44%, and 84-88%, respectively among the VFCW reactors. It is concluded that VFCW reactor system can effectively be used in the treatment of dye-rich wastewater, especially for the removal of color and in the reduction of COD. Biofilm formation and cleavage of azo bonds could be observed by SEM and FTIR results, respectively. Almost similar NH4-N and PO4-P removal were obtained in all reactors by using same amount of zeolite media.

  19. Impact of Cr(VI) on P removal performance in enhanced biological phosphorus removal (EBPR) system based on the anaerobic and aerobic metabolism.

    PubMed

    Fang, Jing; Sun, Pei-de; Xu, Shao-juan; Luo, Tao; Lou, Ju-qing; Han, Jing-yi; Song, Ying-qi

    2012-10-01

    Influence of Cr(VI) on P removal in enhanced biological phosphorus removal (EBPR) system was investigated with respect to the composition of poly-phosphate-accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), the transformation of poly-β-hydroxyalkanoates (PHA) and glycogen, enzymes' activities, and the intracellular Cr. Whether EBPR system could revive after Cr(VI) shock was also explored. Results showed P removal performance was completely inhibited by Cr(VI) with the concentration more than 5 mg L(-1). PAOs were more sensitive to Cr(VI) than GAOs and the other bacteria were. PHA consumption, glycogen synthesis and adenylate kinase's activity had been inhibited by 5 mg L(-1) Cr(VI). Both adenylate kinase's activity and P removal efficiency were negatively correlated with the intracellular Cr. Recovery experiments revealed that P removal performance with 5 mg L(-1) Cr(VI) shock could revive after a 2-day recovery treatment, while systems with high level Cr(VI) (20 and 60 mg L(-1)) shock could not.

  20. Effects of injection of acetic acid and propionic acid for total phosphorus removal at high temperature in enhanced biological phosphorus removal process.

    PubMed

    Ki, C Y; Kwon, K H; Kim, S W; Min, K S; Lee, T U; Park, D J

    2014-01-01

    In summer, wastewater treatment plant total phosphorus (TP) removal efficiency is low in South Korea. The reason is because of high temperatures or significant fluctuation of inflow characteristics caused by frequent rainfall. Hence, this study tried to raise TP removal efficiency by injecting fixed external carbon sources in real sewage. Polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) compete to occupy microorganisms at high temperature. Propionate is known to restrain GAOs. Thus, acetate and propionate were chosen as the external carbon source in this study to find out the suitable volume and ratio of carbon source which ensured the dominance of PAOs. An external carbon source was supplied in the anaerobic reactor of the biological phosphorus removal process at high temperature (above 25 °C). TP removal efficiency was improved by injecting an external carbon source compared to that without an external carbon source. Also, it remained relatively stable when injecting an external carbon source, despite the variation in temperature. TP removal efficiency was the highest when injecting acetate and propionate in the proportion of 2:1 (total concentration as chemical oxygen demand (COD) is 12 mg/L in influent).

  1. Investigation on thiosulfate-involved organics and nitrogen removal by a sulfur cycle-based biological wastewater treatment process.

    PubMed

    Qian, Jin; Lu, Hui; Cui, Yanxiang; Wei, Li; Liu, Rulong; Chen, Guang-Hao

    2015-02-01

    Thiosulfate, as an intermediate of biological sulfate/sulfite reduction, can significantly improve nitrogen removal potential in a biological sulfur cycle-based process, namely the Sulfate reduction-Autotrophic denitrification-Nitrification Integrated (SANI(®)) process. However, the related thiosulfate bio-activities coupled with organics and nitrogen removal in wastewater treatment lacked detailed examinations and reports. In this study, S2O3(2-) transformation during biological SO4(2-)/SO3(2-) co-reduction coupled with organics removal as well as S2O3(2-) oxidation coupled with chemolithotrophic denitrification were extensively evaluated under different experimental conditions. Thiosulfate is produced from the co-reduction of sulfate and sulfite through biological pathway at an optimum pH of 7.5 for organics removal. And the produced S2O3(2-) may disproportionate to sulfide and sulfate during both biological S2O3(2-) reduction and oxidation most possibly carried out by Desulfovibrio-like species. Dosing the same amount of nitrate, pH was found to be the more direct factor influencing the denitritation activity than free nitrous acid (FNA) and the optimal pH for denitratation (7.0) and denitritation (8.0) activities were different. Spiking organics significantly improved both denitratation and denitritation activities while minimizing sulfide inhibition of NO3(-) reduction during thiosulfate-based denitrification. These findings in this study can improve the understanding of mechanisms of thiosulfate on organics and nitrogen removal in biological sulfur cycle-based wastewater treatment.

  2. Development of Peptoid-Based Ligands for the Removal of Cadmium from Biological Media

    PubMed Central

    Knight, Abigail S.; Zhou, Effie Y.; Francis, Matthew B.

    2015-01-01

    Cadmium poisoning poses a serious health concern due to cadmium’s increasing industrial use, yet there is currently no recommended treatment. The selective coordination of cadmium in a biological environment—i.e. in the presence of serum ions, small molecules, and proteins—is a difficult task. To address this challenge, a combinatorial library of peptoid-based ligands has been evaluated to identify structures that selectively bind to cadmium in human serum with minimal chelation of essential metal ions. Eighteen unique ligands were identified in this screening procedure, and the binding affinity of each was measured using metal titrations monitored by UV-vis spectroscopy. To evaluate the significance of each chelating moiety, sequence rearrangements and substitutions were examined. Analysis of a metal-ligand complex by NMR spectroscopy highlighted the importance of particular residues. Depletion experiments were performed in serum mimetics and human serum with exogenously added cadmium. These depletion experiments were used to compare and demonstrate the ability of these peptoids to remove cadmium from blood-like mixtures. In one of these depletion experiments, the peptoid sequence was able to deplete the cadmium to a level comparable to the reported acute toxicity limit. Evaluation of the metal selectivity in buffered solution and in human serum was performed to verify minimal off-target binding. These studies highlight a screening platform for of the identification of metal-ligands that are capable of binding in a complex environment. They additionally demonstrate the potential utility of biologically-compatible ligands for the treatment of heavy metal poisoning. PMID:26918113

  3. Development of peptoid-based ligands for the removal of cadmium from biological media

    DOE PAGES

    Knight, Abigail S.; Zhou, Effie Y.; Francis, Matthew B.

    2015-05-14

    Cadmium poisoning poses a serious health concern due to cadmium's increasing industrial use, yet there is currently no recommended treatment. The selective coordination of cadmium in a biological environment—i.e. in the presence of serum ions, small molecules, and proteins—is a difficult task. To address this challenge, a combinatorial library of peptoid-based ligands has been evaluated to identify structures that selectively bind to cadmium in human serum with minimal chelation of essential metal ions. Eighteen unique ligands were identified in this screening procedure, and the binding affinity of each was measured using metal titrations monitored by UV-vis spectroscopy. To evaluate themore » significance of each chelating moiety, sequence rearrangements and substitutions were examined. Analysis of a metal–ligand complex by NMR spectroscopy highlighted the importance of particular residues. Depletion experiments were performed in serum mimetics and human serum with exogenously added cadmium. These depletion experiments were used to compare and demonstrate the ability of these peptoids to remove cadmium from blood-like mixtures. In one of these depletion experiments, the peptoid sequence was able to deplete the cadmium to a level comparable to the reported acute toxicity limit. Evaluation of the metal selectivity in buffered solution and in human serum was performed to verify minimal off-target binding. These studies highlight a screening platform for the identification of metal–ligands that are capable of binding in a complex environment. They additionally demonstrate the potential utility of biologically-compatible ligands for the treatment of heavy metal poisoning.« less

  4. Development of peptoid-based ligands for the removal of cadmium from biological media

    SciTech Connect

    Knight, Abigail S.; Zhou, Effie Y.; Francis, Matthew B.

    2015-05-14

    Cadmium poisoning poses a serious health concern due to cadmium's increasing industrial use, yet there is currently no recommended treatment. The selective coordination of cadmium in a biological environment—i.e. in the presence of serum ions, small molecules, and proteins—is a difficult task. To address this challenge, a combinatorial library of peptoid-based ligands has been evaluated to identify structures that selectively bind to cadmium in human serum with minimal chelation of essential metal ions. Eighteen unique ligands were identified in this screening procedure, and the binding affinity of each was measured using metal titrations monitored by UV-vis spectroscopy. To evaluate the significance of each chelating moiety, sequence rearrangements and substitutions were examined. Analysis of a metal–ligand complex by NMR spectroscopy highlighted the importance of particular residues. Depletion experiments were performed in serum mimetics and human serum with exogenously added cadmium. These depletion experiments were used to compare and demonstrate the ability of these peptoids to remove cadmium from blood-like mixtures. In one of these depletion experiments, the peptoid sequence was able to deplete the cadmium to a level comparable to the reported acute toxicity limit. Evaluation of the metal selectivity in buffered solution and in human serum was performed to verify minimal off-target binding. These studies highlight a screening platform for the identification of metal–ligands that are capable of binding in a complex environment. They additionally demonstrate the potential utility of biologically-compatible ligands for the treatment of heavy metal poisoning.

  5. Growth and nutrient removal properties of the diatoms, Chaetoceros curvisetus and C. simplex under different nitrogen sources

    NASA Astrophysics Data System (ADS)

    Karthikeyan, Panneerselvam; Manimaran, Kuppusamy; Sampathkumar, Pitchai; Rameshkumar, Lakshmanan

    2013-03-01

    To investigate the suitability of the marine diatoms, Chaetoceros curvisetus and C. simplex for the removal of macronutrients from different wastewater, the growth and nitrate-phosphate removal properties were studied with nitrate, ammonium and urea nitrogen sources. Three separate experiments were conducted using modified F/2 medium with 12.35 mg L-1 total nitrogen and 1.12 mg L-1 total phosphorous (simulating the typical concentration of nitrogen and phosphorus in secondary effluent) as growth medium. The maximum cell densities of C. curvisetus and C. simplex were 7.16 ± 0.34 × 104 cells mL-1 in {{NO}}3^{ - } and 3.88 ± 0.32 × 105 cells mL-1 in urea, respectively. The maximum chlorophyll a per cell was 1.7 and 4.7 pg for C. simplex and C. curvisetus, cultured with urea and nitrate, respectively. The high protein contents of 4.7 pg cell-1 in C. simplex with urea and 19.7 pg cell-1 in C. curvisetus nitrate nitrogen sources were found. The higher cell density and protein content of both species from urea and nitrate nitrogen sources ( p < 0.05) have shown that these were utilized by microalgae and were converted to protein. The C. simplex and C. curvisetus showed maximum removal efficiencies of nitrate by 97.86 and 91.62 % and phosphate by 98.5 and 100 %, respectively when urea used as nitrogen source than ammonia. The results indicated the C. simplex was more efficient than C. curvisetus and suitable for the removal of macronutrients when cultured with urea and nitrate nitrogen sources.

  6. 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.

  7. The effect of amino acids on lipid production and nutrient removal by Rhodotorula glutinis cultivation in starch wastewater.

    PubMed

    Liu, Meng; Zhang, Xu; Tan, Tianwei

    2016-10-01

    In this paper, the components of amino acids in mixed starch wastewater (corn steep water/corn gluten water=1/3, v/v) were analyzed by GC-MS. Effects of amino acids on lipid production by Rhodotorula glutinis and COD removal were studied. The results showed that mixed starch wastewater contained 9 kinds of amino acids and these amino acids significantly improved the biomass (13.63g/L), lipid yield (2.48g/L) and COD removal compared to the basic medium (6.23g/L and 1.56g/L). In a 5L fermentor containing mixed starch wastewater as substrate to culture R. glutinis, the maximum biomass, lipid content and lipid yield reached 26.38g/L, 28.90% and 7.62g/L, with the associated removal rates of COD, TN and TP reaching 77.41%, 69.12% and 73.85%, respectively. The results revealed a promising approach for lipid production with using amino acids present in starch wastewater as an alternative nitrogen source.

  8. Project summary: Emerging technology assessment of phostrip, a/o, and bardenpho processes for biological phosphorus removal

    SciTech Connect

    1985-03-01

    This technology assessment addresses the process capabilities and limitations of three proprietary processes (PhoStrip, A/O, and Bardenpho) to biologically remove phosphorus from municipal wastewaters. The primary objective of this report is to provide guidance to individuals involved with reviewing new processes as part of the Innovative and Alternative Technology Program.

  9. A metabolic model for members of the genus Tetrasphaera involved in enhanced biological phosphorus removal

    PubMed Central

    Kristiansen, Rikke; Nguyen, Hien Thi Thu; Saunders, Aaron Marc; Nielsen, Jeppe Lund; Wimmer, Reinhard; Le, Vang Quy; McIlroy, Simon Jon; Petrovski, Steve; Seviour, Robert J; Calteau, Alexandra; Nielsen, Kåre Lehmann; Nielsen, Per Halkjær

    2013-01-01

    Members of the genus Tetrasphaera are considered to be putative polyphosphate accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) from wastewater. Although abundant in Danish full-scale wastewater EBPR plants, how similar their ecophysiology is to ‘Candidatus Accumulibacter phosphatis' is unclear, although they may occupy different ecological niches in EBPR communities. The genomes of four Tetrasphaera isolates (T. australiensis, T. japonica, T. elongata and T. jenkinsii) were sequenced and annotated, and the data used to construct metabolic models. These models incorporate central aspects of carbon and phosphorus metabolism critical to understanding their behavior under the alternating anaerobic/aerobic conditions encountered in EBPR systems. Key features of these metabolic pathways were investigated in pure cultures, although poor growth limited their analyses to T. japonica and T. elongata. Based on the models, we propose that under anaerobic conditions the Tetrasphaera-related PAOs take up glucose and ferment this to succinate and other components. They also synthesize glycogen as a storage polymer, using energy generated from the degradation of stored polyphosphate and substrate fermentation. During the aerobic phase, the stored glycogen is catabolized to provide energy for growth and to replenish the intracellular polyphosphate reserves needed for subsequent anaerobic metabolism. They are also able to denitrify. This physiology is markedly different to that displayed by ‘Candidatus Accumulibacter phosphatis', and reveals Tetrasphaera populations to be unusual and physiologically versatile PAOs carrying out denitrification, fermentation and polyphosphate accumulation. PMID:23178666

  10. Continuous biological waste gas treatment in stirred trickle-bed reactor with discontinuous removal of biomass.

    PubMed

    Laurenzis, A; Heits, H; Wübker, S; Heinze, U; Friedrich, C; Werner, U

    1998-02-20

    A new reactor for biological waste gas treatment was developed to eliminate continuous solvents from waste gases. A trickle-bed reactor was chosen with discontinuous movement of the packed bed and intermittent percolation. The reactor was operated with toluene as the solvent and an optimum average biomass concentration of between 5 and 30 kg dry cell weight per cubic meter packed bed (m3pb). This biomass concentration resulted in a high volumetric degradation rate. Reduction of surplus biomass by stirring and trickling caused a prolonged service life and prevented clogging of the trickle bed and a pressure drop increase. The pressure drop after biomass reduction was almost identical to the theoretical pressure drop as calculated for the irregular packed bed without biomass. The reduction in biomass and intermittent percolation of mineral medium resulted in high volumetric degradation rates of about 100 g of toluene m-3pb h-1 at a load of 150 g of toluene m-3pb h-1. Such a removal rate with a trickle-bed reactor was not reported before.

  11. A review and update of the microbiology of enhanced biological phosphorus removal in wastewater treatment plants.

    PubMed

    Blackall, Linda L; Crocetti, Gregory R; Saunders, Aaron M; Bond, Philip L

    2002-08-01

    Enhanced biological phosphorus removal (EBPR) from wastewater can be more-or-less practically achieved but the microbiological and biochemical components are not completely understood. EBPR involves cycling microbial biomass and influent wastewater through anaerobic and aerobic zones to achieve a selection of microorganisms with high capacity to accumulate polyphosphate intracellularly in the aerobic period. Biochemical or metabolic modelling of the process has been used to explain the types of carbon and phosphorus transformations in sludge biomass. There are essentially two broad-groupings of microorganisms involved in EBPR. They are polyphosphate accumulating organisms (PAOs) and their supposed carbon-competitors called glycogen accumulating organisms (GAOs). The morphological appearance of microorganisms in EBPR sludges has attracted attention. For example, GAOs as tetrad-arranged cocci and clusters of coccobacillus-shaped PAOs have been much commented upon and the use of simple cellular staining methods has contributed to EBPR knowledge. Acinetobacter and other bacteria were regularly isolated in pure culture from EBPR sludges and were initially thought to be PAOs. However, when contemporary molecular microbial ecology methods in concert with detailed process performance data and simple intracellular polymer staining methods were used, a betaproteobacteria called 'Candidatus Accumulibacter phosphatis' was confirmed as a PAO and organisms from a novel gammaproteobacteria lineage were GAOs. To preclude making the mistakes of previous researchers, it is recommended that the sludge 'biography' be well understood--i.e. details of phenotype (process performance and biochemistry) and microbial community structure should be linked.

  12. Biological wastewater treatment followed by physicochemical treatment for the removal of fluorinated surfactants.

    PubMed

    Schröder, H F R; José, H J; Gebhardt, W; Moreira, R F P M; Pinnekamp, J

    2010-01-01

    Perfluorinated surfactants (PFS) have become compounds of high concern during the last decade. While "conventional surfactants" are degraded to a great extent in the biological wastewater treatment process, partly or perfluorinated surfactants are not only stable against biodegradation but also against oxidizing agents, they even resist OH-radical attacks. Our objectives were to eliminate the fluorinated surfactants perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) by adsorption, separation or degradation with a balance of precursor compounds and follow-up of degradation products. Therefore, municipal wastewater was spiked with these fluorinated surfactants before membrane bioreactor (MBR) treatment-applying microfiltration membranes--was performed and before permeates were treated using ozone (O3) or different advanced oxidation treatment (AOP) techniques. O3 or hydrogen peroxide (H2O2), both in combination with UV radiation or in combination with catalysts, was applied. Removal by adsorption or membrane separation as well as degradation were monitored by substance specific determination and identification. High resolution mass spectrometry after high performance liquid chromatography (HPLC/HRMS and -MS(n)) was used for analysis. Contact to Teflon and/or glass during all analytical procedures was avoided.

  13. Genome reconstruction and gene expression of "Candidatus Accumulibacter phosphatis" Clade IB performing biological phosphorus removal.

    PubMed

    Mao, Yanping; Yu, Ke; Xia, Yu; Chao, Yuanqing; Zhang, Tong

    2014-09-02

    We report the first integrated metatranscriptomic and metagenomic analysis of enhanced biological phosphorus removal (EBPR) sludge. A draft genome of Candidatus Accumulibacter spp. strain HKU-1, a member of Clade IB, was retrieved. It was estimated to be ∼90% complete and shared average nucleotide identities of 83% and 88% with the finished genome CAP IIA UW-1 and the draft genome CAP IA UW-2, respectively. Different from CAP IIA UW-1, the phosphotransferase (pap) in polyphosphate metabolism and V-ATPase in orthophosphate transport were absent from CAP IB HKU-1. Additionally, unlike CAP IA UW-2, CAP IB HKU-1 carried the genes for carbon fixation and nitrogen fixation. Despite these differences, the key genes required for acetate uptake, glycolysis and polyhydroxyalkanoate (PHA) synthesis were conserved in all these Accumulibacter genomes. The preliminary metatranscriptomic results revealed that the most significantly up-regulated genes of CAP IB HKU-1 from the anaerobic to the aerobic phase were responsible for assimilatory sulfate reduction, genetic information processing and phosphorus absorption, while the down-regulated genes were related to N2O reduction, PHA synthesis and acetyl-CoA formation. This study yielded another important Accumulibacter genome, revealed the functional difference within the Accumulibacter Type I, and uncovered the genetic responses to EBPR stimuli at a higher resolution.

  14. Monitoring intracellular polyphosphate accumulation in enhanced biological phosphorus removal systems by quantitative image analysis.

    PubMed

    Mesquita, Daniela P; Amaral, A Luís; Leal, Cristiano; Carvalheira, Mónica; Cunha, Jorge R; Oehmen, Adrian; Reis, Maria A M; Ferreira, Eugénio C

    2014-01-01

    A rapid methodology for intracellular storage polyphosphate (poly-P) identification and monitoring in enhanced biological phosphorus removal (EBPR) systems is proposed based on quantitative image analysis (QIA). In EBPR systems, 4',6-diamidino-2-phenylindole (DAPI) is usually combined with fluorescence in situ hybridization to evaluate the microbial community. The proposed monitoring technique is based on a QIA procedure specifically developed for determining poly-P inclusions within a biomass suspension using solely DAPI by epifluorescence microscopy. Due to contradictory literature regarding DAPI concentrations used for poly-P detection, the present work assessed the optimal DAPI concentration for samples acquired at the end of the EBPR aerobic stage when the accumulation occurred. Digital images were then acquired and processed by means of image processing and analysis. A correlation was found between average poly-P intensity values and the analytical determination. The proposed methodology can be seen as a promising alternative procedure for quantifying intracellular poly-P accumulation in a faster and less labour-intensive way.

  15. Microbial community analysis involved in the aerobic/extended-idle process performing biological phosphorus removal.

    PubMed

    Zeng, Tian-jing; Yang, Guo-jing; Wang, Dong-bo; Li, Xiao-ming; Zheng, Wei; Yang, Qi; Zeng, Guang-ming

    2013-01-01

    Recently, it has been found that biological phosphorus removal can be achieved in an aerobic/extended-idle (AEI) process using both glucose and acetate as the sole substrate. However, the microbial consortiums involved in glucose-fed and acetate-fed systems have not yet been characterized. Thus the aims of this paper were to investigate the diversities and dynamics of bacterial communities during the acclimation period, and to quantify polyphosphate-accumulating organisms (PAOs) and glycogen-accumulating organisms (GAOs) in the systems. The phylogenetic analysis showed that the microbial communities were mainly composed of phylum Proteobacteria, Bacteroidetes, Chlorobi and another six kinds of unclassified bacteria. Fluorescence in-situ hybridization (FISH) analysis revealed that PAOs and GAOs accounted for 43 ± 7 and 16 ± 3% of all bacteria in the glucose-fed system, and 19 ± 4 and 35 ± 5% of total bacteria in the acetate-fed system, respectively. The results showed that the conventional PAOs could thrive in the AEI process, and a defined anaerobic zone was not necessarily required for putative PAOs growth.

  16. A metabolic model for members of the genus Tetrasphaera involved in enhanced biological phosphorus removal.

    PubMed

    Kristiansen, Rikke; Nguyen, Hien Thi Thu; Saunders, Aaron Marc; Nielsen, Jeppe Lund; Wimmer, Reinhard; Le, Vang Quy; McIlroy, Simon Jon; Petrovski, Steve; Seviour, Robert J; Calteau, Alexandra; Nielsen, Kåre Lehmann; Nielsen, Per Halkjær

    2013-03-01

    Members of the genus Tetrasphaera are considered to be putative polyphosphate accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) from wastewater. Although abundant in Danish full-scale wastewater EBPR plants, how similar their ecophysiology is to 'Candidatus Accumulibacter phosphatis' is unclear, although they may occupy different ecological niches in EBPR communities. The genomes of four Tetrasphaera isolates (T. australiensis, T. japonica, T. elongata and T. jenkinsii) were sequenced and annotated, and the data used to construct metabolic models. These models incorporate central aspects of carbon and phosphorus metabolism critical to understanding their behavior under the alternating anaerobic/aerobic conditions encountered in EBPR systems. Key features of these metabolic pathways were investigated in pure cultures, although poor growth limited their analyses to T. japonica and T. elongata. Based on the models, we propose that under anaerobic conditions the Tetrasphaera-related PAOs take up glucose and ferment this to succinate and other components. They also synthesize glycogen as a storage polymer, using energy generated from the degradation of stored polyphosphate and substrate fermentation. During the aerobic phase, the stored glycogen is catabolized to provide energy for growth and to replenish the intracellular polyphosphate reserves needed for subsequent anaerobic metabolism. They are also able to denitrify. This physiology is markedly different to that displayed by 'Candidatus Accumulibacter phosphatis', and reveals Tetrasphaera populations to be unusual and physiologically versatile PAOs carrying out denitrification, fermentation and polyphosphate accumulation.

  17. Metagenomes obtained by 'deep sequencing' - what do they tell about the enhanced biological phosphorus removal communities?

    PubMed

    Albertsen, Mads; Saunders, Aaron M; Nielsen, Kåre L; Nielsen, Per H

    2013-01-01

    Metagenomics enables studies of the genomic potential of complex microbial communities by sequencing bulk genomic DNA directly from the environment. Knowledge of the genetic potential of a community can be used to formulate and test ecological hypotheses about stability and performance. In this study deep metagenomics and fluorescence in situ hybridization (FISH) were used to study a full-scale wastewater treatment plant with enhanced biological phosphorus removal (EBPR), and the results were compared to an existing EBPR metagenome. EBPR is a widely used process that relies on a complex community of microorganisms to function properly. Insight into community and species level stability and dynamics is valuable for knowledge-driven optimization of the EBPR process. The metagenomes of the EBPR communities were distinct compared to metagenomes of communities from a wide range of other environments, which could be attributed to selection pressures of the EBPR process. The metabolic potential of one of the key microorganisms in the EPBR process, Accumulibacter, was investigated in more detail in the two plants, revealing a potential importance of phage predation on the dynamics of Accumulibacter populations. The results demonstrate that metagenomics can be used as a powerful tool for system wide characterization of the EBPR community as well as for a deeper understanding of the function of specific community members. Furthermore, we discuss and illustrate some of the general pitfalls in metagenomics and stress the need of additional DNA extraction independent information in metagenome studies.

  18. Understanding the role of extracellular polymeric substances in an enhanced biological phosphorus removal granular sludge system.

    PubMed

    Wang, Randeng; Peng, Yongzhen; Cheng, Zhanli; Ren, Nanqi

    2014-10-01

    The role of extracellular polymeric substances (EPS) in the enhanced biological phosphorus removal (EBPR) process was investigated in a P-accumulating granular sludge system by analyzing the distribution and transfer of P, K(+), Mg(2+) and Ca(2+) in the sludge phase, EPS, and the bulk liquid. In the sludge phase, about 30% P, 44.7% K(+), 27.7% Mg(2+), 28% Ca(2+) accumulated in the EPS at the end of aeration. The rate of P, K(+), Mg(2+) and Ca(2+) released from the EPS matrix into the bulk liquid in the anaerobic phase was faster than the rate they were adsorbed from the bulk liquid into the EPS in the aerobic phase. P, K(+), Mg(2+) and Ca(2+) were retained in EPS before transferring into the phosphorus accumulating organisms (PAOs). These results suggest that EPS play a critical role in facilitating the accumulation and transfer of P, K(+), Ca(2+) and Mg(2+) between PAO cells and bulk liquid.

  19. Metatranscriptomic array analysis of 'Candidatus Accumulibacter phosphatis'-enriched enhanced biological phosphorus removal sludge.

    PubMed

    He, Shaomei; Kunin, Victor; Haynes, Matthew; Martin, Hector Garcia; Ivanova, Natalia; Rohwer, Forest; Hugenholtz, Philip; McMahon, Katherine D

    2010-05-01

    Here we report the first metatranscriptomic analysis of gene expression and regulation of 'Candidatus Accumulibacter'-enriched lab-scale sludge during enhanced biological phosphorus removal (EBPR). Medium density oligonucleotide microarrays were generated with probes targeting most predicted genes hypothesized to be important for the EBPR phenotype. RNA samples were collected at the early stage of anaerobic and aerobic phases (15 min after acetate addition and switching to aeration respectively). We detected the expression of a number of genes involved in the carbon and phosphate metabolisms, as proposed by EBPR models (e.g. polyhydroxyalkanoate synthesis, a split TCA cycle through methylmalonyl-CoA pathway, and polyphosphate formation), as well as novel genes discovered through metagenomic analysis. The comparison between the early stage anaerobic and aerobic gene expression profiles showed that expression levels of most genes were not significantly different between the two stages. The majority of upregulated genes in the aerobic sample are predicted to encode functions such as transcription, translation and protein translocation, reflecting the rapid growth phase of Accumulibacter shortly after being switched to aerobic conditions. Components of the TCA cycle and machinery involved in ATP synthesis were also upregulated during the early aerobic phase. These findings support the predictions of EBPR metabolic models that the oxidation of intracellularly stored carbon polymers through the TCA cycle provides ATP for cell growth when oxygen becomes available. Nitrous oxide reductase was among the very few Accumulibacter genes upregulated in the anaerobic sample, suggesting that its expression is likely induced by the deprivation of oxygen.

  20. Effect of salinity on N₂O production during shortcut biological nitrogen removal from landfill leachate.

    PubMed

    Liu, Mu; Liu, Tiantian; Peng, Yongzhen; Wang, Shuying; Xiao, Han

    2014-05-01

    Three identical SBR adapted to different salinity were applied to investigate the characteristics of the treatment performance and N2O production [Formula: see text] during shortcut biological nitrogen removal from landfill leachate under various operating parameters. Increase of salinity might deteriorate the activity of the microorganisms leading to the increase of [Formula: see text] , however, the system could be gradually adapted to the inhibition and alleviate the detrimental effect to some extent. The system acclimated to high salinity provided better performance under high salinity shock and a lower possibility of [Formula: see text] , while a sudden decrease in salinity can cause a temporary increase in [Formula: see text] . High salinity strengthened the influence of high ammonia nitrogen concentration and low DO concentration on [Formula: see text] while the strengthening effect was unconspicuous at high DO concentration. The anoxic phase did not produce a significant amount of N2O even at the lowest C/N ratio of 0.5 and was less susceptible to salinity. Characterization of the biomass composition using fluorescence in situ hybridization analysis confirmed that the relative proportion of Nitrosomonas europaea was increased with the increase of the salinity, which may be an important factor for the strengthening effect of salinity on [Formula: see text] .

  1. Chemically and biologically modified activated carbon sorbents for the removal of lead ions from aqueous media.

    PubMed

    Mahmoud, Mohamed E; Abdel-Fattah, Tarek M; Osman, Maher M; Ahmed, Somia B

    2012-01-01

    A method is described for hybridization of the adsorption and biosorption characteristics of chemically treated commercial activated carbon and baker's yeast, respectively, for the formation of environmental friendly multifunctional sorbents. Activated carbon was loaded with baker's yeast after acid-base treatment. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) Spectroscopy were used to characterize these sorbents. Moreover, the sorption capabilities for lead (II) ions were evaluated. A value of 90 μmol g(-1) was identified as the maximum sorption capacity of activated carbon. Acid-base treatment of activated carbon was found to double the sorption capacity (140-180 μmol g(-1)). Immobilization of baker's yeast on the surface of activated carbon sorbents was found to further improve the sorption capacity efficiency of lead to 360, 510 and 560 μmol g(-1), respectively. Several important factors such as pH, contact time, sorbent dose, lead concentration and interfering ions were examined. Lead sorption process was studied and evaluated by several adsorption isotherms and found to follow the Langmuir and BET models. The potential applications of various chemically and biologically modified sorbents and biosorbents for removal of lead from real water matrices were also investigated via multistage micro-column technique and the results referred to excellent recovery values of lead (95.0-99.0 ± 3.0-5.0 %).

  2. Current advances of integrated processes combining chemical absorption and biological reduction for NO x removal from flue gas.

    PubMed

    Zhang, Shihan; Chen, Han; Xia, Yinfeng; Liu, Nan; Lu, Bi-Hong; Li, Wei

    2014-10-01

    Anthropogenic nitrogen oxides (NO x ) emitted from the fossil-fuel-fired power plants cause adverse environmental issues such as acid rain, urban ozone smoke, and photochemical smog. A novel chemical absorption-biological reduction (CABR) integrated process under development is regarded as a promising alternative to the conventional selective catalytic reduction processes for NO x removal from the flue gas because it is economic and environmentally friendly. CABR process employs ferrous ethylenediaminetetraacetate [Fe(II)EDTA] as a solvent to absorb the NO x following microbial denitrification of NO x to harmless nitrogen gas. Meanwhile, the absorbent Fe(II)EDTA is biologically regenerated to sustain the adequate NO x removal. Compared with conventional denitrification process, CABR not only enhances the mass transfer of NO from gas to liquid phase but also minimize the impact of oxygen on the microorganisms. This review provides the current advances of the development of the CABR process for NO x removal from the flue gas.

  3. Optimization of three operating parameters for a two-step fed sequencing batch reactor (SBR) system to remove nutrients from swine wastewater.

    PubMed

    Wu, Xiao; Zhu, Jun; Cheng, Jiehong; Zhu, Nanwen

    2015-03-01

    In this study, the effect of three operating parameters, i.e., the first/second volumetric feeding ratio (milliliters/milliliters), the first anaerobic/aerobic (an/oxic) time ratio (minute/minute), and the second an/oxic time ratio (minute/minute), on the performance of a two-step fed sequencing batch reactor (SBR) system to treat swine wastewater for nutrients removal was examined. Central Composite Design, coupled with Response Surface Methodology, was employed to test these parameters at five levels in order to optimize the SBR to achieve the best removal efficiencies for six response variables including total nitrogen (TN), ammonium nitrogen (NH4-N), total phosphorus (TP), dissolved phosphorus (DP), chemical oxygen demand (COD), and biochemical oxygen demand (BOD). The results showed that the three parameters investigated had significant impact on all the response variables (TN, NH4-N, TP, DP, COD, and BOD), although the highest removal efficiency for each individual responses was associated with different combination of the three parameters. The maximum TN, NH4-N, TP, DP, COD, and BOD removal efficiencies of 96.38%, 95.38%, 93.62%, 94.3%, 95.26%, and 92.84% were obtained at the optimal first/second volumetric feeding ratio, first an/oxic time ratio, and second an/oxic time ratio of 3.23, 0.4, and 0.8 for TN; 2.64, 0.72, and 0.76 for NH4-N; 3.08, 1.16, and 1.07 for TP; 1.32, 0.81, and 1.0 for DP; 2.57, 0.96, and 1.12 for COD; and 1.62, 0.64, and 1.61 for BOD, respectively. Good linear relationships between the predicted and observed results for all the response variables were observed.

  4. Sequential ozone advanced oxidation and biological oxidation processes to remove selected pharmaceutical contaminants from an urban wastewater.

    PubMed

    Espejo, Azahara; Aguinaco, Almudena; García-Araya, J F; Beltrán, Fernando J

    2014-01-01

    Sequential treatments consisting in a chemical process followed by a conventional biological treatment, have been applied to remove mixtures of nine contaminants of pharmaceutical type spiked in a primary sedimentation effluent of a municipal wastewater. Combinations of ozone, UVA black light (BL) and Fe(III) or Fe₃O₄ catalysts constituted the chemical systems. Regardless of the Advanced Oxidation Process (AOP), the removal of pharmaceutical compounds was achieved in 1 h of reaction, while total organic carbon (TOC) only diminished between 3.4 and 6%. Among selected ozonation systems to be implemented before the biological treatment, the application of ozone alone in the pre-treatment stage is recommended due to the increase of the biodegradability observed. The application of ozone followed by the conventional biological treatment leads high TOC and COD removal rates, 60 and 61%, respectively, and allows the subsequent biological treatment works with shorter hydraulic residence time (HRT). Moreover, the influence of the application of AOPs before and after a conventional biological process was compared, concluding that the decision to take depends on the characterization of the initial wastewater with pharmaceutical compounds.

  5. From the conventional biological wastewater treatment to hybrid processes, the evaluation of organic micropollutant removal: A review.

    PubMed

    Grandclément, Camille; Seyssiecq, Isabelle; Piram, Anne; Wong-Wah-Chung, Pascal; Vanot, Guillaume; Tiliacos, Nicolas; Roche, Nicolas; Doumenq, Pierre

    2017-03-15

    Because of the recalcitrance of some micropollutants to conventional wastewater treatment systems, the occurrence of organic micropollutants in water has become a worldwide issue, and an increasing environmental concern. Their biodegradation during wastewater treatments could be an interesting and low cost alternative to conventional physical and chemical processes. This paper provides a review of the organic micropollutants removal efficiency from wastewaters. It analyses different biological processes, from conventional ones, to new hybrid ones. Micropollutant removals appear to be compound- and process- dependent, for all investigated processes. The influence of the main physico-chemical parameters is discussed, as well as the removal efficiency of different microorganisms such as bacteria or white rot fungi, and the role of their specific enzymes. Even though some hybrid processes show promising micropollutant removals, further studies are needed to optimize these water treatment processes, in particular in terms of technical and economical competitiveness.

  6. Fate and effect of benzalkonium chlorides in a continuous-flow biological nitrogen removal system treating poultry processing wastewater.

    PubMed

    Hajaya, Malek G; Pavlostathis, Spyros G

    2012-08-01

    Quaternary ammonium compounds (QACs) are used for sanitation in many poultry processing facilities. This work investigated the fate and effect of a mixture of benzalkonium chlorides (BACs), a class of QACs widely used in commercial antimicrobial formulations, on the biological nitrogen removal (BNR) processes. A laboratory-scale BNR system was operated continuously for 670 days, fed with poultry processing wastewater amended with a mixture of BACs. Initially, the nitrogen removal efficiency deteriorated at a BAC feed concentration of 5 mg/L due to the complete inhibition of nitrification. However, after 27 days of operation, the system recovered and achieved 100% ammonia removal. High nitrogen removal efficiency was achieved even after the feed BAC concentration was stepwise increased up to 120 mg/L. Batch nitrification assays performed before, during, and after BAC exposure, showed that rapid microbial acclimation and BAC biodegradation contributed to the recovery of nitrification achieving efficient and stable long-term BNR system operation.

  7. A novel approach for phosphorus recovery and no wasted sludge in enhanced biological phosphorus removal process with external COD addition.

    PubMed

    Xia, Cheng-Wang; Ma, Yun-Jie; Zhang, Fang; Lu, Yong-Ze; Zeng, Raymond J

    2014-01-01

    In enhanced biological phosphorus removal (EBPR) process, phosphorus (P) in wastewater is removed via wasted sludge without actual recovery. A novel approach to realize phosphorus recovery with special external chemical oxygen demand (COD) addition in EBPR process was proposed. During the new operating approach period, it was found that (1) no phosphorus was detected in the effluent; (2) with an external addition of 10 % of influent COD amount, 79 % phosphorus in the wastewater influent was recovered; (3) without wasted sludge, the MLVSS concentration in the system increased from 2,010 to 3,400 mg/L and kept stable after day 11 during 24-day operating period. This demonstrates that the novel approach is feasible to realize phosphorus recovery with no wasted sludge discharge in EBPR process. Furthermore, this approach decouples P removal and sludge age, which may enhance the application of membrane bioreactor for P removal.

  8. The potential role of 'Candidatus Microthrix parvicella' in phosphorus removal during sludge bulking in two full-scale enhanced biological phosphorus removal plants.

    PubMed

    Wang, Juan; Qi, Rong; Liu, Miaomiao; Li, Qian; Bao, Haipeng; Li, Yaming; Wang, Shen; Tandoi, Valter; Yang, Min

    2014-01-01

    We investigated the bacterial community compositions and phosphorus removal performance under sludge bulking and non-bulking conditions in two biological wastewater treatment systems (conventional A²/O (anaerobic/anoxic/aerobic) and inverted A²/O (anoxic/anaerobic/aerobic) processes) receiving the same raw wastewater. Sludge bulking resulted in significant shift in bacterial compositions from Proteobacteria dominance to Actinobacteria dominance, characterized by the significant presence of filamentous 'Candidatus Microthrix parvicella'. Quantitative real-time polymerase chain reaction (PCR) analysis revealed that the relative abundance of 'Candidatus Accumulibacter phosphatis', a key polyphosphate-accumulating organism responsible for phosphorus removal, with respect to 16s rRNA genes of total bacteria was 0.8 and 0.7%, respectively, for the conventional and inverted A²/O systems when sludge bulking occurred, which increased to 8.2 and 12.3% during the non-bulking period. However, the total phosphorus removal performance during the bulking period (2-week average: 97 ± 1 and 96 ± 1%, respectively) was not adversely affected comparable to that during the non-bulking period (2-week average: 96 ± 1 and 96 ± 1%, respectively). Neisser staining revealed the presence of large polyphosphate granules in 'Candidatus Microthrix parvicella', suggesting that this microbial group might have been responsible for phosphorus removal during the sludge bulking period when 'Candidatus Accumulibacter phosphatis' was excluded from the systems.

  9. Relations of biological indicators to nutrient data for lakes and streams in Pennsylvania and West Virginia, 1990-98

    USGS Publications Warehouse

    Brightbill, Robin A.; Koerkle, Edward H.

    2003-01-01

    The Clean Water Action Plan of 1998 provides a blueprint for federal agencies to work with states, tribes, and other stakeholders to protect and restore the Nation?s water resources. The plan includes an initiative that addresses the nutrientenrichment problem of lakes and streams across the United States. The U.S. Environmental Protection Agency (USEPA) is working to set nutrient criteria by nationwide nutrient ecoregions that are an aggregation of the Omernik level III ecoregions.Because low levels of nutrients are necessary for healthy streams and elevated concentrations can cause algal blooms that deplete available oxygen and kill off aquatic organisms, criteria levels are to be set, in part, using the relation between chlorophyll a and concentrations of total nitrogen and total phosphorus. Data from Pennsylvania and West Virginia, collected between 1990 and 1998, were analyzed for relations between chlorophyll a, nutrients, and other explanatory variables. Both phytoplankton and periphyton chlorophyll a concentrations from lakes and streams were analyzed separately within each of the USEPA nutrient ecoregions located within the boundaries of the two states. These four nutrient ecoregions are VII (Mostly Glaciated Dairy), VIII (Nutrient Poor, Largely Glaciated Upper Midwest and Northeast), IX (Southeastern Temperate Forested Plains and Hills), and XI (Central and Eastern Forested Uplands).ytoplankton chlorophyll a concentrations in lakes were related to total nitrogen, total phosphorus, Secchi depth, concentration of dissolved oxygen, pH, water temperature, and specific conductivity. In nutrient ecoregion VII, nutrients were not significant predictors of chlorophyll a concentrations. Total nitrogen, Secchi depth, and pH were significantly related to phytoplankton chlorophyll a concentrations in nutrient ecoregion IX. Lake periphyton chlorophyll a concentrations from nutrient ecoregion XI were related to total phosphorus rather than total nitrogen, Secchi depth

  10. Dissolved Nutrient Retention Dynamics in River Networks: A Modeling Investigation of Transient Flow and Scale Effects

    SciTech Connect

    Ye, Sheng; Covino, Timothy P.; Sivapalan, Murugesu; Basu, Nandita; Li, Hongyi; Wang, Shaowen

    2012-06-30

    In this paper, we use a dynamic network flow model, coupled with a transient storage zone biogeochemical model, to simulate dissolved nutrient removal processes at the channel network scale. We have explored several scenarios in respect of the combination of rainfall variability, and the biological and geomorphic characteristics of the catchment, to understand the dominant controls on removal and delivery of dissolved nutrients (e.g., nitrate). These model-based theoretical analyses suggested that while nutrient removal efficiency is lower during flood events compared to during baseflow periods, flood events contribute significantly to bulk nutrient removal, whereas bulk removal during baseflow periods is less. This is due to the fact that nutrient supply is larger during flood events; this trend is even stronger in large rivers. However, the efficiency of removal during both periods decreases in larger rivers, however, due to (i) increasing flow velocities and thus decreasing residence time, and (ii) increasing flow depth, and thus decreasing nutrient uptake rates. Besides nutrient removal processes can be divided into two parts: in the main channel and in the hyporheic transient storage zone. When assessing their relative contributions the size of the transient storage zone is a dominant control, followed by uptake rates in the main channel and in the transient storage zone. Increasing size of the transient storage zone with downstream distance affects the relative contributions to nutrient removal of the water column and the transient storage zone, which also impacts the way nutrient removal rates scale with increasing size of rivers. Intra-annual hydrologic variability has a significant impact on removal rates at all scales: the more variable the streamflow is, compared to mean discharge, the less nutrient is removed in the channel network. A scale-independent first order uptake coefficient, ke, estimated from model simulations, is highly dependent on the

  11. Integrated biological and physiochemical treatment process for nitrate and fluoride removal.

    PubMed

    Mekonen, A; Kumar, P; Kumar, A

    2001-09-01

    The feasibility of an integrated biological and physiochemical water treatment process for nitrate and fluoride removal has been evaluated. It consisted of two sequencing batch reactors (SBRs) in series. Performance of the process in the treatment of 24 synthetic water samples having nitrate concentrations of 40, 80, 120, 160, 200, and 250 mg/l (as N) and fluoride concentrations of 6, 10, 15, and 20 mg/l at different combinations was studied. Denitrification followed by defluoridation proved to be the best sequence of treatment. In all cases nitrate could be reduced to an acceptable level of less than 10 mg/l (as N) at 3, 5, and 7 h hydraulic retention times (HRTs) depending on its initial concentration. Fluoride concentrations up to 15 mg/l associated with nitrate concentrations up to 80 mg/l (as N) could be reduced acceptable 1.5 mg/l by alum-PAC slurry using alum doses up 850 mg/l [as Al2(SO4)3 x 16H2O] along with 100 mg/l of powdered activated carbon (PAC). Additional alkalinity produced during denitrification was used up during defluoridation for maintenance of pH avoiding the need for lime addition. On the other hand, residual organics, turbidity, and sulfide present in the denitrified water are removed by alum and PAC at the defluoridation stage along with fluoride, eliminating the need for an additional post-treatment step. At higher nitrate concentrations (> or = 120 mg/l as N), the alkalinity produced at the denitrification stage was in the range of 715-1175 mg/l as CaCO3. This excessive alkalinity inhibited reduction of fluoride to the level of 1.5 mg/l at the defluoridation stage, using alum doses up to 900 mg/l along with 100 mg/l of PAC. In all cases a fluoride concentration of 20 mg/l in water could not be reduced to the acceptable level of 1.5 mg/l.

  12. Ammonium removal of drinking water at low temperature by activated carbon filter biologically enhanced with heterotrophic nitrifying bacteria.

    PubMed

    Qin, Wen; Li, Wei-Guang; Zhang, Duo-Ying; Huang, Xiao-Fei; Song, Yang

    2016-03-01

    We sought to confirm whether use of Acinetobacter strains Y7 and Y16, both strains of heterotrophic nitrifying bacteria, was practical for removing ammonium (NH4 (+)-N) from drinking water at low temperatures. To test this, ammonium-containing drinking water was treated with strains Y7 and Y16 at 8 and 2 °C. Continuous ammonium treatment was conducted in order to evaluate the performance of three biologically enhanced activated carbon (BEAC) filters in removing ammonium. The three BEAC filters were inoculated with strain Y7, strain Y16, and a mixture of strains Y7 and Y16, respectively. A granular activated carbon (GAC) filter, without inoculation by any strains, was tested in parallel with the BEAC filters as control. The results indicated that NH4 (+)-N removal was significant when a BEAC filter was inoculated with the mixture of strains Y7 and Y16 (BEAC-III filter). Amounts of 0.44 ± 0.05 and 0.25 ± 0.05 mg L(-1) NH4 (+)-N were removed using the BEAC-III filter at 8 and 2 °C, respectively. These values were 2.8-4.0-fold higher than the values of ammonium removal acquired using the GAC filter. The synergistic effect of using strains Y7 and Y16 in concert was the cause of the high-ammonium removal efficiency achieved by using the BEAC-III filter at low temperatures. In addition, a high C/N ratio may promote NH4 (+)-N removal efficiency by improving biomass and microbial activity. This study provides new insight into the use of biofilters to achieve biological removal of ammonium at low temperature.

  13. Environmental and Biological Data of the Nutrient Enrichment Effects on Stream Ecosystems Project of the National Water Quality Assessment Program, 2003-04

    USGS Publications Warehouse

    Brightbill, Robin A.; Munn, Mark D.

    2008-01-01

    In 2000, the U.S. Environmental Protection Agency began the process of developing regional nutrient criteria for streams and rivers. In response to concerns about nutrients by the U.S. Environmental Protection Agency and others, the U.S. Geological Survey National Water Quality Assessment Program began studying the effects of nutrient enrichment on agricultural stream ecosystems to aid in the understanding of how nutrients affect the biota in agricultural streams. Streams within five study areas were sampled either in 2003 or 2004. These five study areas were located within six NAWQA study units: the combined Apalachicola-Chattahoochee-Flint River Basin (ACFB) and Georgia-Florida Coastal Plain Drainages (GAFL), Central Columbia Plateau?Yakima River Basin (CCYK), Central Nebraska Basins (CNBR), Potomac River?Delmarva Peninsula (PODL), and the White-Miami River Basin (WHMI). Data collected included nutrients (nitrogen and phosphorous) and other chemical parameters, biological samples (chlorophyll, algal assemblages, invertebrate assemblages, and some fish assemblages), stream habitat, and riparian and basin information. This report describes and presents the data collected from these study areas.

  14. Biological removal of selenate and ammonium by activated sludge in a sequencing batch reactor.

    PubMed

    Mal, J; Nancharaiah, Y V; van Hullebusch, E D; Lens, P N L

    2017-04-01

    Wastewaters contaminated by both selenium and ammonium need to be treated prior to discharge into natural water bodies, but there are no studies on the simultaneous removal of selenium and ammonium. A sequencing batch reactor (SBR) was inoculated with activated sludge and operated for 90days. The highest ammonium removal efficiency achieved was 98%, while the total nitrogen removal was 75%. Nearly a complete chemical oxygen demand removal efficiency was attained after 16days of operation, whereas complete selenate removal was achieved only after 66days. The highest total Se removal efficiency was 97%. Batch experiments showed that the total Se in the aqueous phase decreased by 21% with increasing initial ammonium concentration from 50 to 100mgL(-1). This study showed that SBR can remove both selenate and ammonium via, respectively, bioreduction and partial nitrification-denitrification and thus offer possibilities for treating selenium and ammonium contaminated effluents.

  15. 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.

  16. 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.

  17. Biological mechanisms associated with triazophos (TAP) removal by horizontal subsurface flow constructed wetlands (HSFCW).

    PubMed

    Wu, Juan; Feng, Yuqin; Dai, Yanran; Cui, Naxin; Anderson, Bruce; Cheng, Shuiping

    2016-05-15

    Triazophos (TAP) is a widely used pesticide that is easily accumulated in the environment due to its relatively high stability: this accumulation from agricultural runoff results in potential hazards to aquatic ecosystems. Constructed wetlands are generally considered to be an effective technology for treating TAP polluted surface water. However, knowledge about the biological mechanisms of TAP removal is still lacking. This study investigates the responses of a wetland plant (Canna indica), substrate enzymes and microbial communities in bench-scale horizontal subsurface-flow constructed wetlands (HSCWs) loaded with different TAP concentrations (0, 0.1, 0.5 and 5 mg · L(-1)). The results indicate that TAP stimulated the activities of superoxide dismutase (SOD) and peroxidase (POD) in the roots of C. indica. The highest TAP concentrations significantly inhibited photosynthetic activities, as shown by a reduced effective quantum yield of PS II (ΦPS II) and lower electron transport rates (ETR). However, interestingly, the lower TAP loadings exhibited some favorable effects on these two variables, suggesting that C. indica is a suitable species for use in wetlands designed for treatment of low TAP concentrations. Urease and alkaline phosphatase (ALP) in the wetland substrate were activated by TAP. Two-way ANOVA demonstrated that urease activity was influenced by both the TAP concentrations and season, while acidphosphatase (ACP) only responded to seasonal variations. Analysis of high throughput sequencing of 16S rRNA revealed seasonal variations in the microbial community structure of the wetland substrate at the phylum and family levels. In addition, urease activity had a greater correlation with the relative abundance of some functional microbial groups, such as the Bacillaceae family, and the ALP and ACP may be influenced by the plant more than substrate microbial communities.

  18. Biological Redox Cycling Of Iron In Nontronite And Its Potential Application In Nitrate Removal

    SciTech Connect

    Zhao, Linduo; Dong, Hailiang; Kukkadapu, Ravi K.; Zeng, Qiang; Edelmann, Richard E.; Pentrak, Martin; Agrawal, Abinash

    2015-05-05

    Redox cycling of structural Fe in phyllosilicates provides a potential method to remediate nitrate contamination in natural environment. Past research has only studied chemical redox cycles or a single biologically mediated redox cycle of Fe in phyllosilicates. The objective of this research was to study three microbially driven redox cycles of Fe in one phyllosilicate, nontronite (NAu-2). During the reduction phase structural Fe(III) in NAu-2 served as electron acceptor, lactate as electron donor, AQDS as electron shuttle, and dissimilatory Fe(III)-reducing bacteria Shewanella putrefaciens CN32 as mediator in bicarbonate-buffered and PIPES-buffered media. During the oxidation phase, biogenic Fe(II) served an electron donor, nitrate as electron acceptor, and nitrate-dependent Fe(II)-oxidizing bacteria Pseudogulbenkiania sp. strain 2002 as mediator in the same media. For all three cycles, structural Fe in NAu-2 was able to reversibly undergo 3 redox cycles without significant reductive or oxidative dissolution. X-ray diffraction and scanning and transmission electron microscopy revealed that NAu-2 was the dominant residual mineral throughout the 3 redox cycles with some dissolution textures but no significant secondary mineralization. Mössbauer spectroscopy revealed that Fe(II) in bio-reduced samples likely occurred in two distinct environments, at edges and the interior of the NAu-2 structure. Nitrate was completely reduced to nitrogen gas under both buffer conditions and this extent and rate did not change with Fe redox cycles. Mössbauer spectroscopy further revealed that nitrate reduction was coupled to predominant/preferred oxidation of edge Fe(II). These results suggest that structural Fe in phyllosilicates may represent a renewable source to continuously remove nitrate in natural environments.

  19. Bioenergetic models for acetate and phosphate transport in bacteria important in enhanced biological phosphorus removal.

    PubMed

    Burow, Luke C; Mabbett, Amanda N; McEwan, Alastair G; Bond, Philip L; Blackall, Linda L

    2008-01-01

    Most of our understanding of the physiology of microorganisms is the result of investigations in pure culture. However, in order to understand complex environmental processes, there is a need to investigate mixed microbial communities. This is true for enhanced biological phosphorus removal (EBPR), an environmental process that results in the enrichment of the polyphosphate-accumulating organism Accumulibacter spp. and the glycogen non-polyphosphate accumulating organism Defluviicoccus spp. We investigated acetate and inorganic phosphate (P(i)) uptake in enrichments of Accumulibacter spp. and acetate uptake in enrichments of Defluviicoccus spp. For both enrichments, anaerobic acetate uptake assays in the presence of the protonophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP) or the membrane potential (Delta psi) uncoupler valinomycin, indicated that acetate is likely to be taken up by a permease-mediated process driven by the Delta psi. Further investigation with the sodium ionophore monensin suggested that anaerobic acetate uptake by Defluviicoccus spp. may in part be dependent on a sodium potential. Results of this study also suggest that Accumulibacter spp. generate a proton motive force (pmf or Delta p) for anaerobic acetate uptake by efflux of protons in symport with P(i) through an inorganic phosphate transport (Pit) system. In contrast, we suggest that the anaerobic Delta p in Defluviicoccus spp. is generated by an efflux of protons across the cell membrane by the fumarate respiratory system, or by extrusion of sodium ions via decarboxylation of methylmalonyl-CoA. Aerobic P(i) uptake by the Accumulibacter spp. enrichment was strongly inhibited in the presence of an ATPase inhibitor, suggesting that the phosphate-specific transport (Pst) system is important even under relatively high concentrations of P(i). Acetate permease activity in these microorganisms may play an important role in the competition for acetate in the often acetate-limited EBPR

  20. Comparative genomics of two 'Candidatus Accumulibacter' clades performing biological phosphorus removal.

    PubMed

    Flowers, Jason J; He, Shaomei; Malfatti, Stephanie; del Rio, Tijana Glavina; Tringe, Susannah G; Hugenholtz, Philip; McMahon, Katherine D

    2013-12-01

    Members of the genus Candidatus Accumulibacter are important in many wastewater treatment systems performing enhanced biological phosphorus removal (EBPR). The Accumulibacter lineage can be subdivided phylogenetically into multiple clades, and previous work showed that these clades are ecologically distinct. The complete genome of Candidatus Accumulibacter phosphatis strain UW-1, a member of Clade IIA, was previously sequenced. Here, we report a draft genome sequence of Candidatus Accumulibacter spp. strain UW-2, a member of Clade IA, assembled following shotgun metagenomic sequencing of laboratory-scale bioreactor sludge. We estimate the genome to be 80-90% complete. Although the two clades share 16S rRNA sequence identity of >98.0%, we observed a remarkable lack of synteny between the two genomes. We identified 2317 genes shared between the two genomes, with an average nucleotide identity (ANI) of 78.3%, and accounting for 49% of genes in the UW-1 genome. Unlike UW-1, the UW-2 genome seemed to lack genes for nitrogen fixation and carbon fixation. Despite these differences, metabolic genes essential for denitrification and EBPR, including carbon storage polymer and polyphosphate metabolism, were conserved in both genomes. The ANI from genes associated with EBPR was statistically higher than that from genes not associated with EBPR, indicating a high selective pressure in EBPR systems. Further, we identified genomic islands of foreign origins including a near-complete lysogenic phage in the Clade IA genome. Interestingly, Clade IA appeared to be more phage susceptible based on it containing only a single Clustered Regularly Interspaced Short Palindromic Repeats locus as compared with the two found in Clade IIA. Overall, the comparative analysis provided a genetic basis to understand physiological differences and ecological niches of Accumulibacter populations, and highlights the importance of diversity in maintaining system functional resilience.

  1. Metabolic modelling of full-scale enhanced biological phosphorus removal sludge.

    PubMed

    Lanham, Ana B; Oehmen, Adrian; Saunders, Aaron M; Carvalho, Gilda; Nielsen, Per H; Reis, Maria A M

    2014-12-01

    This study investigates, for the first time, the application of metabolic models incorporating polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) towards describing the biochemical transformations of full-scale enhanced biological phosphorus removal (EBPR) activated sludge from wastewater treatment plants (WWTPs). For this purpose, it was required to modify previous metabolic models applied to lab-scale systems by incorporating the anaerobic utilisation of the TCA cycle and the aerobic maintenance processes based on sequential utilisation of polyhydroxyalkanoates, followed by glycogen and polyphosphate. The abundance of the PAO and GAO populations quantified by fluorescence in situ hybridisation served as the initial conditions of each biomass fraction, whereby the models were able to describe accurately the experimental data. The kinetic rates were found to change among the four different WWTPs studied or even in the same plant during different seasons, either suggesting the presence of additional PAO or GAO organisms, or varying microbial activities for the same organisms. Nevertheless, these variations in kinetic rates were largely found to be proportional to the difference in acetate uptake rate, suggesting a viable means of calibrating the metabolic model. The application of the metabolic model to full-scale sludge also revealed that different Accumulibacter clades likely possess different acetate uptake mechanisms, as a correlation was observed between the energetic requirement for acetate transport across the cell membrane with the diversity of Accumulibacter present. Using the model as a predictive tool, it was shown that lower acetate concentrations in the feed as well as longer aerobic retention times favour the dominance of the TCA metabolism over glycolysis, which could explain why the anaerobic TCA pathway seems to be more relevant in full-scale WWTPs than in lab-scale systems.

  2. Determination of biological removal of recalcitrant organic contaminants in coal gasification waste water.

    PubMed

    Ji, Qinhong; Tabassum, Salma; Yu, Guangxin; Chu, Chunfeng; Zhang, Zhenjia

    2015-01-01

    Coal gasification waste water treatment needed a sustainable and affordable plan to eliminate the organic contaminants in order to lower the potential environmental and human health risk. In this paper, a laboratory-scale anaerobic-aerobic intermittent system carried out 66 operational cycles together for the treatment of coal gasification waste water and the removal capacity of each organic pollutant. Contaminants included phenols, carboxylic acids, long-chain hydrocarbons, and heterocyclic compounds, wherein the relative content of phenol is up to 57.86%. The long-term removal of 77 organic contaminants was evaluated at different hydraulic retention time (anaerobic24 h + aerobic48 h and anaerobic48 h +aerobic48 h). Contaminant removal ranged from no measurable removal to near-complete removal with effluent concentrations below the detection limit. Contaminant removals followed one of four trends: steady-state removal throughout, increasing removal to steady state (acclimation), decreasing removal, and no removal. Organic degradation and transformation in the reaction were analysed by gas chromatography/mass spectromet