Upflow anaerobic sludge blanket and aerated constructed wetlands for swine wastewater treatment: a pilot study.

PubMed

Masi, F; Rizzo, A; Martinuzzi, N; Wallace, S D; Van Oirschot, D; Salazzari, P; Meers, E; Bresciani, R

2017-07-01

Swine wastewater management is often affected by two main issues: a too high volume for optimal reuse as a fertilizer and a too high strength for an economically sustainable treatment by classical solutions. Hence, an innovative scheme has been tested to treat swine wastewater, combining a low cost anaerobic reactor, upflow anaerobic sludge blanket (UASB), with intensified constructed wetlands (aerated CWs) in a pilot scale experimental study. The swine wastewater described in this paper is produced by a swine production facility situated in North Italy. The scheme of the pilot plant consisted of: (i) canvas-based thickener; (ii) UASB; (iii) two intensified aerated vertical subsurface flow CWs in series; (iv) a horizontal flow subsurface CW. The influent wastewater quality has been defined for total suspended solids (TSS 25,025 ± 9,323 mg/l), organic carbon (chemical oxygen demand (COD) 29,350 ± 16,983 mg/l), total reduced nitrogen and ammonium (total Kjeldahl nitrogen (TKN) 1,783 ± 498 mg/l and N-NH 4 + 735 ± 251 mg/l) and total phosphorus (1,285 ± 270 mg/l), with nitrates almost absent. The overall system has shown excellent performances in terms of TSS, COD, N-NH 4 + and TKN removal efficiencies (99.9%, 99.6%, 99.5%, and 99.0%, respectively). Denitrification (N-NO 3 - effluent concentration equal to 614 ± 268 mg/l) did not meet the Italian quality standards for discharging in water bodies, mainly because the organic carbon was almost completely removed in the intensified CW beds.

Continuous treatment of N-Methyl-p-nitro aniline (MNA) in an Upflow Anaerobic Sludge Blanket (UASB) bioreactor

PubMed Central

Olivares, Christopher I.; Wang, Junqin; Silva Luna, Carlos D.; Field, Jim A.; Abrell, Leif; Sierra-Alvarez, Reyes

2017-01-01

N-methyl-p-nitroaniline (MNA) is an ingredient of insensitive munitions (IM) compounds that serves as a plasticizer and helps reduce unwanted detonations. As its use becomes widespread, MNA waste streams will be generated, necessitating viable treatment options. We studied MNA biodegradation and its inhibition potential to, a representative anaerobic microbial population in wastewater treatment, methanogens. Anaerobic biodegradation and toxicity assays were performed and an up-flow anaerobic sludge blanket reactor (UASB) was operated to test continuous degradation of MNA. MNA was transformed almost stoichiometrically to N-methyl-p-phenylenediamine (MPD). MPD was not mineralized, however, it was readily autoxidized and polymerized extensively upon aeration at pH = 9. In the UASB reactor, MNA was fully degraded up to a loading rate of 297.5 μM MNA d-1). Regarding toxicity, MNA was very inhibitory to acetoclastic methanogens (IC50 = 103 μM) whereas MPD was much less toxic, causing only 13.9% inhibition at the highest concentration tested (1025 μM). The results taken as a whole indicate that anaerobic sludge can transform MNA to MPD continuously, and that the transformation decreases the cytotoxicity of the parent pollutant. MPD can be removed through extensive polymerization. These insights could help define efficient treatment options for waste streams polluted with MNA. PMID:26454121

Performance evaluation of the sulfur-redox-reaction-activated up-flow anaerobic sludge blanket and down-flow hanging sponge anaerobic/anoxic sequencing batch reactor system for municipal sewage treatment.

PubMed

Hatamoto, Masashi; Ohtsuki, Kota; Maharjan, Namita; Ono, Shinya; Dehama, Kazuya; Sakamoto, Kenichi; Takahashi, Masanobu; Yamaguchi, Takashi

2016-03-01

A sulfur-redox-reaction-activated up-flow anaerobic sludge blanket (UASB) and down-flow hanging sponge (DHS) system, combined with an anaerobic/anoxic sequencing batch reactor (A2SBR), has been used for municipal sewage treatment for over 2 years. The present system achieved a removal rate of 95±14% for BOD, 74±22% for total nitrogen, and 78±25% for total phosphorus, including low water temperature conditions. Sludge conversion rates during the operational period were 0.016 and 0.218 g-VSS g-COD-removed(-1) for the UASB, and DHS, respectively, which are similar to a conventional UASB-DHS system, which is not used of sulfur-redox-reaction, for sewage treatment. Using the sulfur-redox reaction made advanced treatment of municipal wastewater with minimal sludge generation possible, even in winter. Furthermore, the occurrence of a unique phenomenon, known as the anaerobic sulfur oxidation reaction, was confirmed in the UASB reactor under the winter season. Copyright © 2016. Published by Elsevier Ltd.

Performance and model of a full-scale up-flow anaerobic sludge blanket (UASB) to treat the pharmaceutical wastewater containing 6-APA and amoxicillin.

PubMed

Chen, Zhiqiang; Wang, Hongcheng; Chen, Zhaobo; Ren, Nanqi; Wang, Aijie; Shi, Yue; Li, Xiaoming

2011-01-30

A full-scale test was conducted with an up-flow anaerobic sludge blanket (UASB) pre-treating pharmaceutical wastewater containing 6-aminopenicillanic acid (6-APA) and amoxicillin. The aim of the study is to investigate the performance of UASB in the condition of a high chemical oxygen demand (COD) loading rate from 12.57 to 21.02 kgm(-3)d(-1) and a wide pH from 5.57 to 8.26, in order to provide a reference for treating the similar chemical synthetic pharmaceutical wastewater containing 6-APA and amoxicillin. The results demonstrated that the UASB average percentage reduction in COD, 6-APA and amoxicillin were 52.2%, 26.3% and 21.6%, respectively. In addition, three models, built on the back propagation neural network (BPNN) theory and linear regression techniques were developed for the simulation of the UASB system performance in the biodegradation of pharmaceutical wastewater containing 6-APA and amoxicillin. The average error of COD, 6-APA and amoxicillin were -0.63%, 2.19% and 5.40%, respectively. The results indicated that these models built on the BPNN theory were well-fitted to the detected data, and were able to simulate and predict the removal of COD, 6-APA and amoxicillin by UASB. Crown Copyright © 2010. Published by Elsevier B.V. All rights reserved.

Anaerobic treatment of coconut husk liquor for biogas production.

PubMed

Leitão, R C; Araújo, A M; Freitas-Neto, M A; Rosa, M F; Santaella, S T

2009-01-01

The market for coconut water causes environmental problems as it is one of the major agro-industrial solid wastes in some developing countries. With the aim of reusing the coconut husk, Embrapa developed a system for processing this raw material. During the dewatering stage Coconut Husk Liquor (CHL) is generated with chemical oxygen demand (COD) varying from 60 to 70 g/L due to high concentrations of sugars and tannins. The present study evaluated the feasibility of anaerobic treatment of CHL through Anaerobic Toxicity Assay and the operation of a lab-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. Results showed that CHL can be treated through a UASB reactor operating with an OLR that reaches up to 10 kg/m3.d and that is maintained stable during the whole operation. With this operational condition, the removal efficiency was higher than 80% for COD and approximately 78% for total tannins, and biogas production was 20 m3 of biogas or 130 KWh per m3 of CHL. Seventy-five percent of the biogas composition was methane and toxicity tests demonstrated that CHL was not toxic to the methanogenic consortia. Conversely, increasing the concentration of CHL leads to increased methanogenic activity.

Antibiotic Fermentation Broth Treatment by a pilot upflow anaerobic sludge bed reactor and kinetic modeling.

PubMed

Coskun, T; Kabuk, H A; Varinca, K B; Debik, E; Durak, I; Kavurt, C

2012-10-01

In this study, an upflow anaerobic sludge blanket (UASB) mesophilic reactor was used to remove antibiotic fermentation broth wastewater. The hydraulic retention time was held constant at 13.3 days. The volumetric organic loading value increased from 0.33 to 7.43 kg(COD)m(-3)d(-1) using antibiotic fermentation broth wastewater gradually diluted with various ratios of domestic wastewater. A COD removal efficiency of 95.7% was obtained with a maximum yield of 3,700 L d(-1) methane gas production. The results of the study were interpreted using the modified Stover-Kincannon, first-order, substrate mass balance and Van der Meer and Heertjes kinetic models. The obtained kinetic coefficients showed that antibiotic fermentation broth wastewater can be successfully treated using a UASB reactor while taking COD removal and methane production into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced biodegradation of hexachlorocyclohexane in upflow anaerobic sludge blanket reactor using methanol as an electron donor.

PubMed

Bhatt, Praveena; Kumar, M Suresh; Mudliar, Sandeep; Chakrabarti, Tapan

2008-05-01

Anaerobic dechlorination of technical grade hexachlorocyclohexane (THCH) was studied in a continuous upflow anaerobic sludge blanket (UASB) reactor with methanol as a supplementary substrate and electron donor. A reactor without methanol served as the experimental control. The inlet feed concentration of THCH in both the experimental and the control UASB reactor was 100 mg l(-1). After 60 days of continuous operation, the removal of THCH was >99% in the methanol-supplemented reactor as compared to 20-35% in the control reactor. THCH was completely dechlorinated in the methanol fed reactor at 48 h HRT after 2 months of continuous operation. This period was also accompanied by increase in biomass in the reactor, which was not observed in the experimental control. Batch studies using other supplementary substrates as well as electron donors namely acetate, butyrate, formate and ethanol showed lower % dechlorination (<85%) and dechlorination rates (<3 mg g(-1)d(-1)) as compared to methanol (98%, 5 mg g(-1)d(-1)). The optimum concentration of methanol required, for stable dechlorination of THCH (100 mg l(-1)) in the UASB reactor, was found to be 500 mg l(-1). Results indicate that addition of methanol as electron donor enhances dechlorination of THCH at high inlet concentration, and is also required for stable UASB reactor performance.

Simultaneous carbon and nitrogen removal from anaerobic effluent of the cassava ethanol industry.

PubMed

Yin, Zhixuan; Xie, Li; Zhou, Qi; Bi, Xuejun

2018-03-01

This study investigated the simultaneous carbon and nitrogen removal from anaerobic effluent of cassava stillage using a lab-scale integrated system consisting of an upflow anaerobic sludge blanket (UASB) reactor and an activated sludge (AS) process. Simultaneous denitrification and methanogenesis (SDM) was observed in the UASB with nitrate recirculation. Compared with the blank reactor without recirculation, the overall chemical oxygen demand (COD) removal efficiencies in the combined system with nitrate recirculation were similar (80-90%), while the TN removal efficiencies were significantly improved from 4.7% to 71.0%. Additionally, the anaerobic COD removal efficiencies increased from 21% to 40% as the recirculation ratio decreased from 3 to 1. Although the influent nitrate concentrations fluctuated (60-140 mg N/L), the nitrate removal efficiencies could be maintained at about 97% under different recirculation conditions. With the decreasing recirculation ratio from 3 to 1, the CH 4 content in biogas improved from 2% to 40% while the N 2 content reduced from 95.8% to 50.6%. The 16S rDNA sequencing results indicated that bacteria diversity in anaerobic SDM granular sludge was much higher than archaea. The effect of recirculation ratios on the bacterial and archaeal communities in SDM granular sludge could be further confirmed by the relative abundance of denitrifying bacteria. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Aminiphilus circumscriptus gen. nov., sp. nov., an anaerobic amino-acid-degrading bacterium from an upflow anaerobic sludge reactor.

PubMed

Díaz, C; Baena, S; Fardeau, M-L; Patel, B K C

2007-08-01

Strain ILE-2(T) was isolated from an upflow anaerobic sludge bed reactor treating brewery wastewater. The motile, non-sporulating, slightly curved cells (2-4 x 0.1 microm) stained Gram-negative and grew optimally at 42 degrees C and pH 7.1 with 0.5 % NaCl. The strain required yeast extract for growth and fermented Casamino acids, peptone, isoleucine, arginine, lysine, alanine, valine, glutamate, histidine, glutamine, methionine, malate, fumarate, glycerol and pyruvate to acetate, propionate and minor amounts of branched-chain fatty acids. Carbohydrates, formate, acetate, propionate, butyrate, isovalerate, methanol, ethanol, 1-propanol, butanol, lactate, succinate, starch, casein, gelatin, xylan and a number of other amino acids were not utilized. The DNA G+C content of strain ILE-2(T) was 52.7 mol%. 16S rRNA gene sequence analysis revealed that ILE-2(T) was distantly related to members of the genera Aminobacterium (83 % similarity) and Aminomonas (85 % similarity) in the family Syntrophomonadaceae, order Clostridiales, phylum Firmicutes. On the basis of the results of our polyphasic analysis, strain ILE-2(T) represents a novel species and genus within the family Syntrophomonadaceae, for which the name Aminiphilus circumscriptus gen. nov., sp. nov. is proposed. The type strain of Aminiphilus circumscriptus is ILE-2(T) (=DSM 16581(T) =JCM 14039(T)).

Mainstream upflow nitritation-anammox system with hybrid anaerobic pretreatment: Long-term performance and microbial community dynamics.

PubMed

Li, Xiaojin; Sun, Shan; Yuan, Heyang; Badgley, Brian D; He, Zhen

2017-11-15

Mainstream nitritation-anammox is of strong interest to energy- and resource-efficient domestic wastewater treatment. However, there lack in-depth studies of pretreatment, tests of actual wastewater, and examination of long-term performance. Herein, an upflow nitritation-anammox granular reactor has been investigated to treat primary effluent with a hybrid anaerobic reactor (HAR) as pretreatment for more than 300 days. This system achieved 92% of COD removal, 75% of which was accomplished by the HAR, and had an average final effluent COD concentration of 22 mg L -1 . More than 90% of ammonium was removed in the nitritation-anammox reactor, achieving a nitrogen removal rate of 81.0 g N m -3  d -1 in the last stage. The accumulation of sulfate-reducing bacteria in the HAR evidenced the effect of sulfate on COD removal and subsequent nitrogen removal. Anammox bacteria (predominantly Ca. Jettenia asiatica) accounted for up to 40.2% of total granular communities, but their abundance decreased over time in the suspended communities. The dynamics of major metabolisms and functional genes involved in nitrogen conversion were predicted by PICRUSt based on the taxonomic data, providing more insights into the functions of the microbial communities. These results have demonstrated the effectiveness and importance of anaerobic pretreatment to successful mainstream nitritation-anammox. Copyright © 2017 Elsevier Ltd. All rights reserved.

Continuous treatment of the insensitive munitions compound N-methyl-p-nitro aniline (MNA) in an upflow anaerobic sludge blanket (UASB) bioreactor.

PubMed

Olivares, Christopher I; Wang, Junqin; Luna, Carlos D Silva; Field, Jim A; Abrell, Leif; Sierra-Alvarez, Reyes

2016-02-01

N-methyl-p-nitroaniline (MNA) is an ingredient of insensitive munitions (IM) compounds that serves as a plasticizer and helps reduce unwanted detonations. As its use becomes widespread, MNA waste streams will be generated, necessitating viable treatment options. We studied MNA biodegradation and its inhibition potential to a representative anaerobic microbial population in wastewater treatment, methanogens. Anaerobic biodegradation and toxicity assays were performed and an up-flow anaerobic sludge blanket reactor (UASB) was operated to test continuous degradation of MNA. MNA was transformed almost stoichiometrically to N-methyl-p-phenylenediamine (MPD). MPD was not mineralized; however, it was readily autoxidized and polymerized extensively upon aeration at pH = 9. In the UASB reactor, MNA was fully degraded up to a loading rate of 297.5 μM MNA d(-1). Regarding toxicity, MNA was very inhibitory to acetoclastic methanogens (IC50 = 103 μM) whereas MPD was much less toxic, causing only 13.9% inhibition at the highest concentration tested (1025 μM). The results taken as a whole indicate that anaerobic sludge can transform MNA to MPD continuously, and that the transformation decreases the cytotoxicity of the parent pollutant. MPD can be removed through extensive polymerization. These insights could help define efficient treatment options for waste streams polluted with MNA. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Feedforward neural network model estimating pollutant removal process within mesophilic upflow anaerobic sludge blanket bioreactor treating industrial starch processing wastewater.

PubMed

Antwi, Philip; Li, Jianzheng; Meng, Jia; Deng, Kaiwen; Koblah Quashie, Frank; Li, Jiuling; Opoku Boadi, Portia

2018-06-01

In this a, three-layered feedforward-backpropagation artificial neural network (BPANN) model was developed and employed to evaluate COD removal an upflow anaerobic sludge blanket (UASB) reactor treating industrial starch processing wastewater. At the end of UASB operation, microbial community characterization revealed satisfactory composition of microbes whereas morphology depicted rod-shaped archaea. pH, COD, NH 4 + , VFA, OLR and biogas yield were selected by principal component analysis and used as input variables. Whilst tangent sigmoid function (tansig) and linear function (purelin) were assigned as activation functions at the hidden-layer and output-layer, respectively, optimum BPANN architecture was achieved with Levenberg-Marquardt algorithm (trainlm) after eleven training algorithms had been tested. Based on performance indicators such the mean squared errors, fractional variance, index of agreement and coefficient of determination (R 2 ), the BPANN model demonstrated significant performance with R 2 reaching 87%. The study revealed that, control and optimization of an anaerobic digestion process with BPANN model was feasible. Copyright © 2018 Elsevier Ltd. All rights reserved.

Anaerobic-aerobic treatment of purified terephthalic acid (PTA) effluent; a techno-economic alternative to two-stage aerobic process.

PubMed

Pophali, G R; Khan, R; Dhodapkar, R S; Nandy, T; Devotta, S

2007-12-01

This paper addresses the treatment of purified terephthalic acid (PTA) effluent using anaerobic and aerobic processes. Laboratory studies were carried out on flow proportionate composite wastewater generated from the manufacturing of PTA. An activated sludge process (ASP-two stage and single stage) and an upflow anaerobic fixed film fixed bed reactor (AFFFBR) were used, individually and in combination. The performance of a full-scale ETP under existing operating conditions was also studied. Full scale ETP studies revealed that the treatment of PTA effluent using a two-stage ASP alone does not meet treated effluent quality within the prescribed Indian Standards. The biomass produced in the two stage ASP was very viscous and fluffy and the sludge volume index (SVI) was very high (200-450 ml/g). However, pretreatment of PTA effluent using an upflow AFFFBR ensured substantial reduction in BOD (63%) and COD (62%) with recovery of biogas at 1.8-1.96 l/l effluent treated at a volumetric loading rate (VLR) 4-5 kg COD/m(3) d. The methane content in the biogas varied between 55% and 60%. The pretreated effluent from the upflow AFFFBR was then treated through a single stage ASP. The biomass produced in the ASP after anaerobic treatment had very good settlability (SVI: 75-90 ml/g) as compared to the two stage ASP and the treated effluent quality with respect to BOD, COD and SS was within the prescribed Indian Standards. The alternative treatment process comprising an upflow AFFFBR and a single stage ASP ensured net power saving of 257 kW and in addition generated 442 kW of power through the AFFFBR.

A combined upflow anaerobic sludge bed and trickling biofilter process for the treatment of swine wastewater.

PubMed

Zhao, Bowei; Li, Jiangzheng; Buelna, Gerardo; Dubé, Rino; Le Bihan, Yann

2016-01-01

A combined upflow anaerobic sludge blanket (UASB)-trickling biofilter (TBF) process was constructed to treat swine wastewater, a typical high-strength organic wastewater with low carbon/nitrogen ratio and ammonia toxicity. The results showed that the UASB-TBF system can remarkably enhance the removal of pollutants in the swine wastewater. At an organic loading rate of 2.29 kg/m(3) d and hydraulic retention time of 48 h in the UASB, the chemical oxygen demand (COD), Suspended Solids and Total Kjeldahl Nitrogen removals of the combined process reached 83.6%, 84.1% and 41.2%, respectively. In the combined system the UASB served as a pretreatment process for COD removal while nitrification and denitrification occurred only in the TBF process. The TBF performed reasonably well at a surface hydraulic load as high as 0.12 m(3)/m(2) d. Since the ratio of influent COD to total mineral nitrogen was less than 3.23, it is reasonable to suggest that the wood chips in TBF can serve as a new carbon source for denitrification.

Minimisation of costs by using disintegration at a full-scale anaerobic digestion plant.

PubMed

Winter, A

2002-01-01

Various half-scale and lab-scale investigations have already shown that the disintegration of excess sludge is a possible pre-treatment to optimise anaerobic digestion. To control these results different methods of disintegration were investigated at a full-scale plant. Two stirred ball mills and a plant for oxidation with ozone were applied. A positive influence of disintegration on the anaerobic biodegradability can be established with application of a stirred ball mill. Biogas production as well as the degree of degradation were increased by about 20%. Laboratory investigations also validate that disintegration increases the polymer demand and leads to a lower solid content after dewatering. A higher pollution level of process water after dewatering even with ammonia and COD corroborates the results of the anaerobic degradation. Capital costs for the stirred ball mill, costs for energy, manpower and maintenance can be covered if the specific costs for disposal are high. If the development of costs in future and the current discussion about sludge disposal are taken into account sewage sludge disintegration can be a suitable technique to minimise costs at waste water treatment plants.

Organic loading rate and food-to-microorganism ratio shape prokaryotic diversity in a demo-scale up-flow anaerobic sludge blanket reactor treating domestic wastewater.

PubMed

Cardinali-Rezende, Juliana; Araújo, Juliana C; Almeida, Paulo G S; Chernicharo, Carlos A L; Sanz, José L; Chartone-Souza, Edmar; Nascimento, Andréa M A

2013-12-01

We investigated the microbial community in an up-flow anaerobic sludge blanket (UASB) reactor treating domestic wastewater (DW) during two different periods of organic loading rate (OLR) and food-to-microorganism (F/M) ratio. 16S rDNA clone libraries were generated, and quantitative real-time PCR (qPCR) analyses were performed. Fluctuations in the OLR and F/M ratio affected the abundance and the composition of the UASB prokaryotic community, mainly at the species level, as well as the performance of the UASB reactor. The qPCR analysis suggested that there was a decrease in the bacterial cell number during the rainy season, when the OLR and F/M ratio were lower. However, the bacterial diversity was higher during this time, suggesting that the community degraded more diversified substrates. The diversity and the abundance of the archaeal community were higher when the F/M ratio was lower. Shifts in the methanogenic community composition might have influenced the route of methane production, with methane produced by acetotrophic methanogens (dry season), and by hydrogenotrophic, methylotrophic and acetotrophic methanogens (rainy season). This study revealed higher levels of bacterial diversity, metabolic specialization and chemical oxygen demand removal efficiency of the DW UASB reactor during the rainy season.

Biofilm formation and granule properties in anaerobic digestion at high salinity.

PubMed

Gagliano, M C; Ismail, S B; Stams, A J M; Plugge, C M; Temmink, H; Van Lier, J B

2017-09-15

For the anaerobic biological treatment of saline wastewater, Anaerobic Digestion (AD) is currently a possibility, even though elevated salt concentrations can be a major obstacle. Anaerobic consortia and especially methanogenic archaea are very sensitive to fluctuations in salinity. When working with Upflow Sludge Blanket Reactor (UASB) technology, in which the microorganisms are aggregated and retained in the system as a granular biofilm, high sodium concentration negatively affects aggregation and consequently process performances. In this research, we analysed the structure of the biofilm and granules formed during the anaerobic treatment of high salinity (at 10 and 20 g/L of sodium) synthetic wastewater at lab scale. The acclimated inoculum was able to accomplish high rates of organics removal at all the salinity levels tested. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses identified the acetoclastic Methanosaeta harundinacea as the key player involved acetate degradation and microbial attachment/granulation. When additional calcium (1 g/L) was added to overcome the negative effect of sodium on microbial aggregation, during the biofilm formation process microbial attachment and acetate degradation decreased. The same result was observed on granules formation: while calcium had a positive effect on granules strength when added to UASB reactors, Methanosaeta filaments were not present and the degradation of the partially acidified substrate was negatively influenced. This research demonstrated the possibility to get granulation at high salinity, bringing to the forefront the importance of a selection towards Methanosaeta cells growing in filamentous form to obtain strong and healthy granules. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Influence of nutrients on biomass evolution in an upflow anaerobic sludge blanket reactor degrading sulfate-laden organics.

PubMed

Patidar, S K; Tare, Vinod

2004-01-01

This paper describes the effect of the nutrients iron (Fe), nickel (Ni), zinc (Zn), cobalt (Co), and molybdenum (Mo) on biomass evolution in an upflow anaerobic sludge blanket (UASB) reactor metabolizing synthetic sulfate-laden organics at varying operating conditions during a period of 540 days. A bench-scale model of a UASB reactor was operated at a temperature of 35 degrees C for a chemical oxygen demand-to-sulfate (COD/SO4(2-)) ratio of 8.59 to 2.0, a sulfate loading rate of 0.54 to 1.88 kg SO4(2-)/m3 x d, and an organic loading rate of 1.9 to 5.75 kg COD/m3 x d. Biomass was characterized in terms of total methanogenic activity, acetate-utilizing methanogenic activity, total sulfidogenic activity, acetate-utilizing sulfidogenic activity, and scanning electron microscopy (SEM). Nickel and cobalt limitation appears to affect the activity of hydrogen-utilizing methane-producing bacteria (HMPB) significantly without having an appreciable effect on the activity of acetate-utilizing methane-producing bacteria (AMPB). Nickel and cobalt supplementation resulted in increased availability and, consequently, restoration of biomass activity and process performance. Iron limitation and sulfidogenic conditions resulted in the growth of low-density, hollow, fragile granules that washed out, causing process instability and performance deterioration. Iron and cobalt supplementation indicated significant stimulation of AMPB with slight inhibition of HMPB. Examination of biomass through SEM indicated a population shift with dominance of sarcina-type organisms and the formation of hollow granules. Granule disintegration was observed toward the end of the study.

Recovering hydrogen production performance of upflow anaerobic sludge blanket reactor (UASBR) fed with galactose via repeated heat treatment strategy.

PubMed

Sivagurunathan, Periyasamy; Anburajan, Parthiban; Kumar, Gopalakrishnan; Park, Jong-Hun; Kim, Sang-Hyoun

2017-09-01

This study evaluated the effect of repeated heat treatment towards the enhancement of hydrogen fermentation from galactose in an upflow anaerobic sludge blanket reactor with the hydraulic retention time of 6h and the operation temperature of 37°C. The hydrogen production rate (HPR) and hydrogen yield (HY) gradually increased up to 9.1L/L/d and 1.1mol/mol galactose, respectively, until the 33rd day of operation. When heat treatment at 80°C for 30min was applied, hydrogen production performance was enhanced by 37% with the enrichment of hydrogen producing bacteria population. The HPR and HY were achieved at 12.5L/L/d and 1.5mol/mol hexose, respectively, during further 30 cycles of reactor operation. The repeated heat treatment would be a viable strategy to warrant reliable continuous hydrogen production using mixed culture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Toxicity of nonylphenol diethoxylate in lab-scale anaerobic digesters.

PubMed

Bozkurt, Hande; Sanin, F Dilek

2014-06-01

Nonylphenol compounds have high commercial, industrial and domestic uses owing to their surface active properties. In addition to their toxic, carcinogenic and persistent characteristics; they have drawn the attention of scientists lately due to their endocrine disrupting properties. Their widespread use and disposal cause them to enter wastewater treatment systems at high concentrations. Since they are highly persistent and hydrophobic, they accumulate mostly on sludge. In this study using Anaerobic Toxicity Assay (ATA) tests, the toxicity of a model nonylphenol compound, nonylphenol diethoxylate (NP2EO), for anaerobic digestion of sludge was determined. The test bottles were dosed with NP2EO in acetone, with concentrations ranging from 1 mg L(-1) to 30 mg L(-1). During the tests, gas productions and compositions in terms of methane and carbon dioxide were monitored. To be able to judge about the fate, the target compounds were extracted from water and sludge and analyzed using GC/MS. The sludge samples used for assembling the reactors were found to contain NP and NP1EO but no NP2EO. After the assay was completed, all the NP2EO spiked into the live reactors was found to disappear. The increase seen in NP1EO and NP and further accumulation of NP in the system, indicated the conversion of NP2EO to these metabolites. On the other hand, no conversion was observed in abiotic reactors. Inhibition of NP2EO for anaerobic microorganisms was not observed throughout the tests considering the biogas production of the test reactors in comparison to the control reactors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Treatment of natural rubber processing wastewater using a combination system of a two-stage up-flow anaerobic sludge blanket and down-flow hanging sponge system.

PubMed

Tanikawa, D; Syutsubo, K; Hatamoto, M; Fukuda, M; Takahashi, M; Choeisai, P K; Yamaguchi, T

2016-01-01

A pilot-scale experiment of natural rubber processing wastewater treatment was conducted using a combination system consisting of a two-stage up-flow anaerobic sludge blanket (UASB) and a down-flow hanging sponge (DHS) reactor for more than 10 months. The system achieved a chemical oxygen demand (COD) removal efficiency of 95.7% ± 1.3% at an organic loading rate of 0.8 kg COD/(m(3).d). Bacterial activity measurement of retained sludge from the UASB showed that sulfate-reducing bacteria (SRB), especially hydrogen-utilizing SRB, possessed high activity compared with methane-producing bacteria (MPB). Conversely, the acetate-utilizing activity of MPB was superior to SRB in the second stage of the reactor. The two-stage UASB-DHS system can reduce power consumption by 95% and excess sludge by 98%. In addition, it is possible to prevent emissions of greenhouse gases (GHG), such as methane, using this system. Furthermore, recovered methane from the two-stage UASB can completely cover the electricity needs for the operation of the two-stage UASB-DHS system, accounting for approximately 15% of the electricity used in the natural rubber manufacturing process.

Up-flow anaerobic sediment trapped (UAST) reactor as a new configuration for the enrichment of anammox bacteria from marine sediments.

PubMed

Rios-Del Toro, E Emilia; López-Lozano, Nguyen E; Cervantes, Francisco J

2017-08-01

A novel reactor configuration for the enrichment of anammox bacteria from marine sediments was developed. Marine sediments were successfully kept inside the bioreactors during the enrichment process by strategically installing traps at different depths to prevent the wash-out of sediments. Three up-flow anaerobic sediment trapped (UAST) reactors were set up (α, β and ω supplied with 50, 150 and 300mgCa 2+ /L, respectively). Nitrogen removal rates (NRR) of up to 3.5gN/L-d and removal efficiencies of >95% were reached. Calcium enhanced biomass production as evidenced by increased volatile suspended solids and extracellular polymeric substances. After the long-term operation, dominant families detected were Rhodobacteracea, Flavobacteracea, and Alteromonadacea, while the main anammox genera detected in the three reactors were Candidatus Kuenenia and Candidatus Anammoximicrobium. The UAST reactor is proposed as suitable technology for the enrichment of anammox bacteria applicable for the treatment of saline industrial wastewaters with high nitrogen content. Copyright © 2017 Elsevier Ltd. All rights reserved.

Application and advantages of novel clay ceramic particles (CCPs) in an up-flow anaerobic bio-filter (UAF) for wastewater treatment.

PubMed

Han, Wei; Yue, Qinyan; Wu, Suqing; Zhao, Yaqin; Gao, Baoyu; Li, Qian; Wang, Yan

2013-06-01

Utilization of clay ceramic particles (CCPs) as the novel filter media employed in an up-flow anaerobic bio-filter (UAF) was investigated. After a series of tests and operations, CCPs have presented higher total porosity and roughness, meanwhile lower bulk and grain density. When CCPs were utilized as fillers, the reactor had a shorter start up period of 45 days comparing with conventional reactors, and removal rate of chemical oxygen demand (COD) still reached about 76% at a relatively lower temperature during the stable state. In addition, degradation of COD and ammonia nitrogen (NH4-N) at different media height along the reactor was evaluated, and the dates showed that the main reduction process happened within the first 30 cm media height from the bottom flange. Five phases were observed according to different organic loadings during the experiment period, and the results indicated that COD removal increased linearly when the organic loading was increased. Copyright © 2013 Elsevier Ltd. All rights reserved.

Foaming phenomenon in bench-scale anaerobic digesters.

PubMed

Siebels, Amanda M; Long, Sharon C

2013-04-01

The Madison Metropolitan Sewerage District (The District) in Madison, Wisconsin has been experiencing seasonal foaming in their anaerobic biosolids digesters, which has occurred from mid-November to late June for the past few years. The exact cause(s) of foaming is unknown. Previous research findings are unclear as to whether applications of advanced anaerobic digestion processes reduce the foaming potential of digesters. The object of this study was to investigate how configurations of thermophilic and acid phase-thermophilic anaerobic digestion would affect foaming at the bench-scale level compared to single stage mesophilic digestion for The District. Bench-scale anaerobic digesters were fed with a 4 to 4.5% by dry weight of solids content blend of waste activated sludge (WAS) and primary sludge from The District. Foaming potential was monitored using Alka-Seltzer and aeration foaming tests. The bench-scale acid phase-thermophilic digester had a higher foaming potential than the bench-scale mesophilic digester. These results indicate that higher temperatures increase the foaming potential of the bench-scale anaerobic digesters. The bench-scale acid phase-thermophilic digesters had a greater percent (approximately 5 to 10%) volatile solids destruction and a greater percent (approximately 5 to 10%) total solids destruction when compared to the bench-scale mesophilic digester. Overall, for the full-scale foaming experienced by The District, it appears that adding an acid phase or switching to thermophilic digestion would not alleviate The District's foaming issues.

Lab-scale demonstration of recuperative thickening technology for enhanced biogas production and dewaterability in anaerobic digestion processes.

PubMed

Cobbledick, Jeffrey; Aubry, Nicholas; Zhang, Victor; Rollings-Scattergood, Sasha; Latulippe, David R

2016-05-15

There is growing interest in the use of high performance anaerobic digestion (AD) processes for the production of biogas at wastewater treatment facilities to offset the energy demands associated with wastewater treatment. Recuperative thickening (RT) is a promising technique which involves recycling a portion of the digested solids back to the incoming feed. In general there exists a significant number of knowledge gaps in the field of RT because the studies that have been conducted to date have almost exclusively occurred in pilot plant or full scale trials; this approach greatly limits the amount of process optimization that can be done in a given trial. In this work, a detailed and comprehensive study of RT was conducted at the lab scale; two custom designed digesters (capacity = 1.5 L) were operated in parallel with one acting as a 'control' digester and the other operating under a semi-batch RT mode. There was no significant change in biogas methane composition for the two digesters, however the RT digester had an average biogas productivity over two times higher than the control one. It was found that the recycling of the polymer flocculant back into the RT digester resulted in a significant improvement in dewatering performance. At the highest polymer concentration tested, the capillary suction time (CST) values for flocculated samples for the RT digester were over 6 times lower than the corresponding values for the control digester. Thus, there exists an opportunity to decrease the overall consumption of polymer flocculants through judicious selection of the dose of polymer flocculant that is used both for the thickening and end-stage dewatering steps in RT processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of screened dairy manure by upflow anaerobic fixed bed reactors packed with waste tyre rubber and a combination of waste tyre rubber and zeolite: effect of the hydraulic retention time.

PubMed

Umaña, Oscar; Nikolaeva, Svetlana; Sánchez, Enrique; Borja, Rafael; Raposo, Francisco

2008-10-01

Two laboratory-scale anaerobic fixed bed reactors were evaluated while treating dairy manure at upflow mode and semicontinuous feeding. One reactor was packed with a combination of waste tyre rubber and zeolite (R1) while the other had only waste tyre rubber as a microorganism immobilization support (R2). Effluent quality improved when the hydraulic retention time (HRT) increased from 1.0 to 5.5 days. Higher COD, BOD5, total and volatile solids removal efficiencies were always achieved in the reactor R1. No clogging was observed during the operation period. Methane yield was also a function of the HRT and of the type of support used, and was 12.5% and 40% higher in reactor R1 than in R2 for HRTs of 5.5 and 1.0 days, respectively. The results obtained demonstrated that this type of reactor is capable of operating with dairy manure at a HRT 5 times lower than that used in a conventional reactor.

Anaerobic treatment of rice winery wastewater in an upflow filter packed with steel slag under different hydraulic loading conditions.

PubMed

Jo, Yeadam; Kim, Jaai; Hwang, Seokhwan; Lee, Changsoo

2015-10-01

Rice-washing drainage (RWD), a strong organic wastewater, was anaerobically treated using an upflow filter filled with blast-furnace slag. The continuous performance of the reactor was examined at varying hydraulic retention times (HRTs). The reactor achieved 91.7% chemical oxygen demand removal (CODr) for a 10-day HRT (0.6 g COD/Ld organic loading rate) and maintained fairly stable performance until the HRT was shortened to 2.2 days (CODr > 84%). Further decreases in HRT caused process deterioration (CODr < 50% and pH < 5.5 for a 0.7-day HRT). The methane production rate increased with decreasing HRT to reach the peak level for a 1.3-day HRT, whereas the yield was significantly greater for 3.4-day or longer HRTs. The substrate removal and methane production kinetics were successfully evaluated, and the generated kinetic models produced good performance predictions. The methanogenic activity of the reactor likely relies on the filter biofilm, with Methanosaeta being the main driver. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nanoscale zero-valent iron/persulfate enhanced upflow anaerobic sludge blanket reactor for dye removal: Insight into microbial metabolism and microbial community

PubMed Central

Pan, Fei; Zhong, Xiaohan; Xia, Dongsheng; Yin, Xianze; Li, Fan; Zhao, Dongye; Ji, Haodong; Liu, Wen

2017-01-01

This study investigated the efficiency of nanoscale zero-valent iron combined with persulfate (NZVI/PS) for enhanced degradation of brilliant red X-3B in an upflow anaerobic sludge blanket (UASB) reactor, and examined the effects of NZVI/PS on anaerobic microbial communities during the treatment process. The addition of NZVI (0.5 g/L) greatly enhanced the decolourization rate of X-3B from 63.8% to 98.4%. The Biolog EcoPlateTM technique was utilized to examine microbial metabolism in the reactor, and the Illumina MiSeq high-throughput sequencing revealed 22 phyla and 88 genera of the bacteria. The largest genera (Lactococcus) decreased from 33.03% to 7.94%, while the Akkermansia genera increased from 1.69% to 20.23% according to the abundance in the presence of 0.2 g/L NZVI during the biological treatment process. Meanwhile, three strains were isolated from the sludge in the UASB reactors and identified by 16 S rRNA analysis. The distribution of three strains was consistent with the results from the Illumina MiSeq high throughput sequencing. The X-ray photoelectron spectroscopy results indicated that Fe(0) was transformed into Fe(II)/Fe(III) during the treatment process, which are beneficial for the microorganism growth, and thus promoting their metabolic processes and microbial community. PMID:28300176

Nanoscale zero-valent iron/persulfate enhanced upflow anaerobic sludge blanket reactor for dye removal: Insight into microbial metabolism and microbial community

NASA Astrophysics Data System (ADS)

Pan, Fei; Zhong, Xiaohan; Xia, Dongsheng; Yin, Xianze; Li, Fan; Zhao, Dongye; Ji, Haodong; Liu, Wen

2017-03-01

This study investigated the efficiency of nanoscale zero-valent iron combined with persulfate (NZVI/PS) for enhanced degradation of brilliant red X-3B in an upflow anaerobic sludge blanket (UASB) reactor, and examined the effects of NZVI/PS on anaerobic microbial communities during the treatment process. The addition of NZVI (0.5 g/L) greatly enhanced the decolourization rate of X-3B from 63.8% to 98.4%. The Biolog EcoPlateTM technique was utilized to examine microbial metabolism in the reactor, and the Illumina MiSeq high-throughput sequencing revealed 22 phyla and 88 genera of the bacteria. The largest genera (Lactococcus) decreased from 33.03% to 7.94%, while the Akkermansia genera increased from 1.69% to 20.23% according to the abundance in the presence of 0.2 g/L NZVI during the biological treatment process. Meanwhile, three strains were isolated from the sludge in the UASB reactors and identified by 16 S rRNA analysis. The distribution of three strains was consistent with the results from the Illumina MiSeq high throughput sequencing. The X-ray photoelectron spectroscopy results indicated that Fe(0) was transformed into Fe(II)/Fe(III) during the treatment process, which are beneficial for the microorganism growth, and thus promoting their metabolic processes and microbial community.

Grey water treatment in upflow anaerobic sludge blanket (UASB) reactor at different temperatures.

PubMed

Elmitwalli, Tarek; Otterpohl, Ralf

2011-01-01

The treatment of grey water in two upflow anaerobic sludge blanket (UASB) reactors, operated at different hydraulic retention times (HRTs) and temperatures, was investigated. The first reactor (UASB-A) was operated at ambient temperature (14-25 degrees C) and HRT of 20, 12 and 8 h, while the second reactor (UASB-30) was operated at controlled temperature of 30 degrees C and HRT of 16, 10 and 6 h. The two reactors were fed with grey water from 'Flintenbreite' settlement in Luebeck, Germany. When the grey water was treated in the UASB reactor at 30 degrees C, total chemical oxygen demand (CODt) removal of 52-64% was achieved at HRT between 6 and 16 h, while at lower temperature lower removal (31-41%) was obtained at HRT between 8 and 20 h. Total nitrogen and phosphorous removal in the UASB reactors were limited (22-36 and 10-24%, respectively) at all operational conditions. The results showed that at increasing temperature or decreasing HRT of the reactors, maximum specific methanogenic activity of the sludge in the reactors improved. As the UASB reactor showed a significantly higher COD removal (31-64%) than the septic tank (11-14%) even at low temperature, it is recommended to use UASB reactor instead of septic tank (the most common system) for grey water pre-treatment. Based on the achieved results and due to high peak flow factor, a HRT between 8 and 12 h can be considered the suitable HRT for the UASB reactor treating grey water at temperature 20-30 degrees C, while a HRT of 12-24 h can be applied at temperature lower than 20 degrees C.

Activated carbon enhanced anaerobic digestion of food waste - Laboratory-scale and Pilot-scale operation.

PubMed

Zhang, Le; Zhang, Jingxin; Loh, Kai-Chee

2018-05-01

Effects of activated carbon (AC) supplementation on anaerobic digestion (AD) of food waste were elucidated in lab- and pilot-scales. Lab-scale AD was performed in 1 L and 8 L digesters, while pilot-scale AD was conducted in a 1000 L digester. Based on the optimal dose of 15 g AC per working volume derived from the 1 L digester, for the same AC dosage in the 8 L digester, an improved operation stability coupled with a higher methane yield was achieved even when digesters without AC supplementation failed after 59 days due to accumulation of substantial organic intermediates. At the same time, color removal from the liquid phase of the digestate was dramatically enhanced and the particle size of the digestate solids was increased by 53% through AC supplementation after running for 59 days. Pyrosequencing of 16S rRNA gene showed the abundance of predominant phyla Firmicutes, Elusimicrobia and Proteobacteria selectively enhanced by 1.7-fold, 2.9-fold and 2.1-fold, respectively. Pilot-scale digester without AC gave an average methane yield of 0.466 L⋅(gVS) -1 ⋅d -1 at a composition of 53-61% v/v methane. With AC augmentation, an increase of 41% in methane yield was achieved in the 1000 L digester under optimal organic loading rate (1.6 g VS FW ·L -1 ·d -1 ). Copyright © 2018 Elsevier Ltd. All rights reserved.

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor

PubMed Central

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-01-01

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria. PMID:26555802

Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor.

PubMed

Guerrero-Barajas, Claudia; Ordaz, Alberto; García-Solares, Selene Montserrat; Garibay-Orijel, Claudio; Bastida-González, Fernando; Zárate-Segura, Paola Berenice

2015-10-15

The importance of microbial sulfate reduction relies on the various applications that it offers in environmental biotechnology. Engineered sulfate reduction is used in industrial wastewater treatment to remove large concentrations of sulfate along with the chemical oxygen demand (COD) and heavy metals. The most common approach to the process is with anaerobic bioreactors in which sulfidogenic sludge is obtained through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. This process may take a long time and does not always eliminate the competition for substrate due to the presence of methanogens in the sludge. In this work, we propose a novel approach to obtain sulfidogenic sludge in which hydrothermal vents sediments are the original source of microorganisms. The microbial community developed in the presence of sulfate and volatile fatty acids is wide enough to sustain sulfate reduction over a long period of time without exhibiting inhibition due to sulfide. This protocol describes the procedure to generate the sludge from the sediments in an upflow anaerobic sludge blanket (UASB) type of reactor. Furthermore, the protocol presents the procedure to demonstrate the capability of the sludge to remove by reductive dechlorination a model of a highly toxic organic pollutant such as trichloroethylene (TCE). The protocol is divided in three stages: (1) the formation of the sludge and the determination of its sulfate reducing activity in the UASB, (2) the experiment to remove the TCE by the sludge, and (3) the identification of microorganisms in the sludge after the TCE reduction. Although in this case the sediments were taken from a site located in Mexico, the generation of a sulfidogenic sludge by using this procedure may work if a different source of sediments is taken since marine sediments are a natural pool of microorganisms that may be enriched in sulfate reducing bacteria.

Combination of upflow anaerobic sludge blanket (UASB) reactor and partial nitritation/anammox moving bed biofilm reactor (MBBR) for municipal wastewater treatment.

PubMed

Malovanyy, Andriy; Yang, Jingjing; Trela, Jozef; Plaza, Elzbieta

2015-03-01

In this study the combination of an upflow anaerobic sludge blanket (UASB) reactor and a deammonification moving bed biofilm reactor (MBBR) for mainstream wastewater treatment was tested. The competition between aerobic ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) was studied during a 5months period of transition from reject water to mainstream wastewater followed by a 16months period of mainstream wastewater treatment. The decrease of influent ammonium concentration led to a wash-out of suspended biomass which had a major contribution to nitrite production. Influence of a dissolved oxygen concentration and a transient anoxia mechanism of NOB suppression were studied. It was shown that anoxic phase duration has no effect on NOB metabolism recovery and oxygen diffusion rather than affinities of AOB and NOB to oxygen determine the rate of nitrogen conversion in a biofilm system. Anammox activity remained on the level comparable to reject water treatment systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of an up-flow anaerobic sludge bed (UASB) reactor containing diatomite and maifanite for the improved treatment of petroleum wastewater.

PubMed

Chen, Chunmao; Liang, Jiahao; Yoza, Brandon A; Li, Qing X; Zhan, Yali; Wang, Qinghong

2017-11-01

Novel diatomite (R1) and maifanite (R2) were utilized as support materials in an up-flow anaerobic sludge bed (UASB) reactor for the treatment of recalcitrant petroleum wastewater. At high organic loadings (11kg-COD/m 3 ·d), these materials were efficient at reducing COD (92.7% and 93.0%) in comparison with controls (R0) (88.4%). Higher percentages of large granular sludge (0.6mm or larger) were observed for R1 (30.3%) and R2 (24.6%) compared with controls (22.6%). The larger portion of granular sludge provided a favorable habitat that resulted in greater microorganism diversity. Increased filamentous bacterial communities are believed to have promoted granular sludge formation promoting a conductive environment for stimulation methanogenic Archaea. These communities had enhanced pH tolerance and produced more methane. This study illustrates a new potential use of diatomite and maifanite as support materials in UASB reactors for increased efficiency when treating refractory wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

PARALLEL EVOLUTION OF QUASI-SEPARATRIX LAYERS AND ACTIVE REGION UPFLOWS

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

Mandrini, C. H.; Cristiani, G. D.; Nuevo, F. A.

2015-08-10

Persistent plasma upflows were observed with Hinode’s EUV Imaging Spectrometer (EIS) at the edges of active region (AR) 10978 as it crossed the solar disk. We analyze the evolution of the photospheric magnetic and velocity fields of the AR, model its coronal magnetic field, and compute the location of magnetic null-points and quasi-sepratrix layers (QSLs) searching for the origin of EIS upflows. Magnetic reconnection at the computed null points cannot explain all of the observed EIS upflow regions. However, EIS upflows and QSLs are found to evolve in parallel, both temporarily and spatially. Sections of two sets of QSLs, calledmore » outer and inner, are found associated to EIS upflow streams having different characteristics. The reconnection process in the outer QSLs is forced by a large-scale photospheric flow pattern, which is present in the AR for several days. We propose a scenario in which upflows are observed, provided that a large enough asymmetry in plasma pressure exists between the pre-reconnection loops and lasts as long as a photospheric forcing is at work. A similar mechanism operates in the inner QSLs; in this case, it is forced by the emergence and evolution of the bipoles between the two main AR polarities. Our findings provide strong support for the results from previous individual case studies investigating the role of magnetic reconnection at QSLs as the origin of the upflowing plasma. Furthermore, we propose that persistent reconnection along QSLs does not only drive the EIS upflows, but is also responsible for the continuous metric radio noise-storm observed in AR 10978 along its disk transit by the Nançay Radio Heliograph.« less

Impact of temperature on feed-flow characteristics and filtration performance of an upflow anaerobic sludge blanket coupled ultrafiltration membrane treating municipal wastewater.

PubMed

Ozgun, Hale; Tao, Yu; Ersahin, Mustafa Evren; Zhou, Zhongbo; Gimenez, Juan B; Spanjers, Henri; van Lier, Jules B

2015-10-15

The objective of this study was to assess the operational feasibility of an anaerobic membrane bioreactor (AnMBR), consisting of an upflow anaerobic sludge blanket (UASB) reactor coupled to an ultrafiltration membrane unit, at two operational temperatures (25°C and 15°C) for the treatment of municipal wastewater. The results showed that membrane fouling at 15°C was more severe than that at 25°C. Higher chemical oxygen demand (COD) and soluble microbial products (SMP) concentrations, lower mean particle diameter, and higher turbidity in the UASB effluent at lower temperature aggravated membrane fouling compared to the 25°C operation. However, the overall AnMBR treatment performance was not significantly affected by temperature, which was attributed to the physical membrane barrier. Cake resistance was found responsible for over 40% of the total fouling in both cases. However, an increase was observed in the contribution of pore blocking resistance at 15°C related to the larger amount of fine particles in the UASB effluent compared to 25°C. Based on the overall results, it is concluded that an AnMBR, consisting of a UASB coupled membrane unit, is not found technically feasible for the treatment of municipal wastewater at 15°C, considering the rapid deterioration of the filtration performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of trichloroethylene removal and bacterial community function based on pH-adjusted in an upflow anaerobic sludge blanket reactor.

PubMed

Zhang, Ying; Hu, Miao; Li, Pengfei; Wang, Xin; Meng, Qingjuan

2015-11-01

The study reported the upflow anaerobic sludge blanket (UASB) reactor performance in treating wastewater containing trichloroethylene (TCE) and characterized variations of bacteria composition and structure by changing the pH from 6.0 to 8.0. A slightly acidic environment (pH < 7.0) had a greater impact on the TCE removal. Illumina pyrosequencing was applied to investigate the bacterial community changes in response to pH shifts. The results demonstrated that pH greatly influenced the dominance and presence of specific populations. The potential TCE degradation pathway in the UASB reactor was proposed. Importantly, the genus Dehalobacter which was capable of reductively dechlorinating TCE was detected, and it was not found at pH of 6.0, which presumably is the reason why the removal efficiency of TCE was the lowest (80.73 %). Through Pearson correlation analyses, the relative abundance of Dehalobacter positively correlated with TCE removal efficiency (R = 0.912). However, the relative abundance of Lactococcus negatively correlated with TCE removal efficiency according to the results from Pearson correlation analyses and redundancy analysis (RDA).

ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE ITER

EPA Science Inventory

In Fall 1994, anaerobic compost wetlands in both upflow and downflow configurations were constructed adjacent to and received drainage from the Burleigh Tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The e...

Clostridium thiosulfatireducens sp. nov., a proteolytic, thiosulfate- and sulfur-reducing bacterium isolated from an upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Hernández-Eugenio, Guadalupe; Fardeau, Marie-Laure; Cayol, Jean-Luc; Patel, Bharat K C; Thomas, Pierre; Macarie, Hervé; Garcia, Jean-Louis; Ollivier, Bernard

2002-09-01

A strictly anaerobic, gram-positive, sporulating rod (0.5-0.6 x 2.0-4.0 microm), designated strain Lup 21T, was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating cheese-factory wastewater. Strain Lup 21T was motile by means of peritrichous flagella, had a G+C content of 31.4 mol% and grew optimally at 37 degrees C, pH 7.4, in the absence of NaCl. It is a heterotrophic micro-organism, utilizing proteinaceous compounds (gelatin, peptides, Casamino acids and various single amino acids) but unable to use any of the carbohydrates tested as a carbon and energy source. It reduced thiosulfate and elemental sulfur to sulfide in the presence of Casamino acids as carbon and energy sources. Acetate, butyrate, isobutyrate, isovalerate, CO2 and sulfide were end products from oxidation of gelatin and Casamino acids in the presence of thiosulfate as an electron acceptor. In the absence of thiosulfate, serine, lysine, methionine and histidine were fermented. On the basis of 16S rRNA similarity, strain Lup 21T was related to members of the low-G+C Clostridiales group, Clostridium subterminale DSM 6970T being the closest relative (with a sequence similarity of 99.4%). DNA-DNA hybridization was 56% with this species. On the basis of phenotypic, genotypic and phylogenetic characteristics, the isolate was designated as a novel species of the genus Clostridium, Clostridium thiosulfatireducens sp. nov. The type strain is strain Lup 21T (= DSM 13105T = CIP 106908T).

Kinetics of anaerobic treatment of landfill leachates combined with urban wastewaters.

PubMed

Fueyo, Gema; Gutiérrez, Antonio; Berrueta, José

2003-04-01

The anaerobic degradation of landfill leachates mixed with domestic wastewater has been studied in a pilot-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. A previous work in laboratory-scale had shown that a fraction (5%) of the refractory organic matter could be additionally degraded when these two substrates were treated in conjunction, but this synergistic effect in the Chemical Oxygen Demand (COD) removal was not reproduced. However, the mass loading rate for which the maximum degradation was obtained was higher for the mixtures (0.5 kg COD/kg SSV x d) than for the separated components (0.18 and 0.19), allowing an increase in the treatment capacity of the leachates. The methane productivity (304 L/kg COD) was close to the theoretical maximum and independent of the proportion of the mixture components. The experimental data were fitted to a modification of Haldane's kinetic model, in which the parameters depend on the hydraulic residence time and the biomass concentration.

Full scale fluidized bed anaerobic reactor for domestic wastewater treatment: performance, sludge production and biofilm.

PubMed

Mendonça, N M; Niciura, C L; Gianotti, E P; Campos, J R

2004-01-01

This paper describes the performance, sludge production and biofilm characteristics of a full scale fluidized bed anaerobic reactor (32 m3) for domestic wastewater treatment. The reactor was operated with 10.5 m x h(-1) upflow velocity, 3.2 h hydraulic retention time, and recirculation ratio of 0.85 and it presented removal efficiencies of 71+/-8% of COD and 77+/-14% of TSS. During the apparent steady-state period, specific sludge production and sludge age in the reactor were (0.116+/-0.033) kgVSS. kgCOD(-1) and (12+/-5)d, respectively. Biofilm formed in the reactor presented two different patterns: one of them at the beginning of the colonization and the other of mature biofilm. These different colonization patterns are due to bed stratification in the reactor, caused by the difference in local-energy dissipation rates along the reactor's height, and density, shape, etc. of the bioparticles. The biofilm population is formed mainly of syntrophic consortia among sulfate reducing bacteria, methanogenic archaea such as Methanobacterium and Methanosaeta-like cells.

Anaerobic bioprocessing of organic wastes.

PubMed

Verstraete, W; de Beer, D; Pena, M; Lettinga, G; Lens, P

1996-05-01

Anaerobic digestion of dissolved, suspended and solid organics has rapidly evolved in the last decades but nevertheless still faces several scientific unknowns. In this review, some fundamentals of bacterial conversions and adhesion are addressed initially. It is argued in the light of ΔG-values of reactions, and in view of the minimum energy quantum per mol, that anaerobic syntrophs must have special survival strategies in order to support their existence: redistributing the available energy between the partners, reduced end-product fermentation reactions and special cell-to-cell physiological interactions. In terms of kinetics, it appears that both reaction rates and residual substrate thresholds are strongly related to minimum ΔG-values. These new fundamental insights open perspectives for efficient design and operation of anaerobic bioprocesses. Subsequently, an overview is given of the current anaerobic biotechnology. For treating wastewaters, a novel and high performance new system has been introduced during the last decade; the upflow anaerobic sludge blanket system (UASB). This reactor concept requires anaerobic consortia to grow in a dense and eco-physiologically well-organized way. The microbial principles of such granular sludge growth are presented. Using a thermodynamic approach, the formation of different types of aggregates is explained. The application of this bioprocess in worldwide wastewater treatment is indicated. Due to the long retention times of the active biomass, the UASB is also suitable for the development of bacterial consortia capable of degrading xenobiotics. Operating granular sludge reactors at high upflow velocities (5-6 m/h) in expanded granular sludge bed (EGSB) systems enlarges the application field to very low strength wastewaters (chemical oxygen demand < 1 g/l) and psychrophilic temperatures (10°C). For the treatment of organic suspensions, there is currently a tendency to evolve from the conventional mesophilic

ANAEROBIC COMPOST CONSTRUCTED WETLANDS SYSTEM TECHNOLOGY - SITE TECHNOLOGY CAPSULE

EPA Science Inventory

In fall 1994, anaerobic compost wetlands in both upflow and down flow configurations were constructed adjacent to and received drainage from the Burleigh tunnel, which forms part of the Clear Creek/Central City Superfund site. The systems were operated over a 3 year period. The ...

Anaerobic treatment of sludge from a nitrification-denitrification landfill leachate plant

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

Maranon, E.; Castrillon, L.; Fernandez, Y.

2006-07-01

The viability of anaerobic digestion of sludge from a MSW landfill leachate treatment plant, with COD values ranging between 15,000 and 19,400 mg O{sub 2} dm{sup -3}, in an upflow anaerobic sludge blanket reactor was studied. The reactor employed had a useful capacity of 9 l, operating at mesophilic temperature. Start-up of the reactor was carried out in different steps, beginning with diluted sludge and progressively increasing the amount of sludge fed into the reactor. The study was carried out over a period of 7 months. Different amounts of methanol were added to the feed, ranging between 6.75 and 1more » cm{sup 3} dm{sup -3} of feed in order to favour the growth of methanogenic flora. The achieved biodegradation of the sludge using an upflow anaerobic sludge blanket Reactor was very high for an HRT of 9 days, obtaining decreases in COD of 84-87% by the end of the process. Purging of the digested sludge represented {approx}16% of the volume of the treated sludge.« less

Subarcsecond bright points and quasi-periodic upflows below a quiescent filament observed by IRIS

NASA Astrophysics Data System (ADS)

Li, T.; Zhang, J.

2016-05-01

Context. The new Interface Region Imaging Spectrograph (IRIS) mission provides high-resolution observations of UV spectra and slit-jaw images (SJIs). These data have become available for investigating the dynamic features in the transition region (TR) below the on-disk filaments. Aims: The driver of "counter-streaming" flows along the filament spine is still unknown yet. The magnetic structures and the upflows at the footpoints of the filaments and their relations with the filament mainbody have not been well understood. We study the dynamic evolution at the footpoints of filaments in order to find some clues for solving these questions. Methods: Using UV spectra and SJIs from the IRIS, along with coronal images and magnetograms from the Solar Dynamics Observatory (SDO), we present the new features in a quiescent filament channel: subarcsecond bright points (BPs) and quasi-periodic upflows. Results: The BPs in the TR have a spatial scale of about 350-580 km and lifetimes of more than several tens of minutes. They are located at stronger magnetic structures in the filament channel with a magnetic flux of about 1017-1018 Mx. Quasi-periodic brightenings and upflows are observed in the BPs, and the period is about 4-5 min. The BP and the associated jet-like upflow comprise a "tadpole-shaped" structure. The upflows move along bright filament threads, and their directions are almost parallel to the spine of the filament. The upflows initiated from the BPs with opposite polarity magnetic fields have opposite directions. The velocity of the upflows in the plane of sky is about 5-50 km s-1. The emission line of Si IV 1402.77 Å at the locations of upflows exhibits obvious blueshifts of about 5-30 km s-1, and the line profile is broadened with the width of more than 20 km s-1. Conclusions: The BPs seem to be the bases of filament threads, and the upflows are able to convey mass for the dynamic balance of the filament. The "counter-streaming" flows in previous observations

Microalgae Cultivation on Anaerobic Digestate of Municipal Wastewater, Sewage Sludge and Agro-Waste.

PubMed

Zuliani, Luca; Frison, Nicola; Jelic, Aleksandra; Fatone, Francesco; Bolzonella, David; Ballottari, Matteo

2016-10-10

Microalgae are fast-growing photosynthetic organisms which have the potential to be exploited as an alternative source of liquid fuels to meet growing global energy demand. The cultivation of microalgae, however, still needs to be improved in order to reduce the cost of the biomass produced. Among the major costs encountered for algal cultivation are the costs for nutrients such as CO₂, nitrogen and phosphorous. In this work, therefore, different microalgal strains were cultivated using as nutrient sources three different anaerobic digestates deriving from municipal wastewater, sewage sludge or agro-waste treatment plants. In particular, anaerobic digestates deriving from agro-waste or sewage sludge treatment induced a more than 300% increase in lipid production per volume in Chlorella vulgaris cultures grown in a closed photobioreactor, and a strong increase in carotenoid accumulation in different microalgae species. Conversely, a digestate originating from a pilot scale anaerobic upflow sludge blanket (UASB) was used to increase biomass production when added to an artificial nutrient-supplemented medium. The results herein demonstrate the possibility of improving biomass accumulation or lipid production using different anaerobic digestates.

Microalgae Cultivation on Anaerobic Digestate of Municipal Wastewater, Sewage Sludge and Agro-Waste

PubMed Central

Zuliani, Luca; Frison, Nicola; Jelic, Aleksandra; Fatone, Francesco; Bolzonella, David; Ballottari, Matteo

2016-01-01

Microalgae are fast-growing photosynthetic organisms which have the potential to be exploited as an alternative source of liquid fuels to meet growing global energy demand. The cultivation of microalgae, however, still needs to be improved in order to reduce the cost of the biomass produced. Among the major costs encountered for algal cultivation are the costs for nutrients such as CO2, nitrogen and phosphorous. In this work, therefore, different microalgal strains were cultivated using as nutrient sources three different anaerobic digestates deriving from municipal wastewater, sewage sludge or agro-waste treatment plants. In particular, anaerobic digestates deriving from agro-waste or sewage sludge treatment induced a more than 300% increase in lipid production per volume in Chlorella vulgaris cultures grown in a closed photobioreactor, and a strong increase in carotenoid accumulation in different microalgae species. Conversely, a digestate originating from a pilot scale anaerobic upflow sludge blanket (UASB) was used to increase biomass production when added to an artificial nutrient-supplemented medium. The results herein demonstrate the possibility of improving biomass accumulation or lipid production using different anaerobic digestates. PMID:27735859

Biogas production from brewery spent grain enhanced by bioaugmentation with hydrolytic anaerobic bacteria.

PubMed

Čater, Maša; Fanedl, Lijana; Malovrh, Špela; Marinšek Logar, Romana

2015-06-01

Lignocellulosic substrates are widely available but not easily applied in biogas production due to their poor anaerobic degradation. The effect of bioaugmentation by anaerobic hydrolytic bacteria on biogas production was determined by the biochemical methane potential assay. Microbial biomass from full scale upflow anaerobic sludge blanket reactor treating brewery wastewater was a source of active microorganisms and brewery spent grain a model lignocellulosic substrate. Ruminococcus flavefaciens 007C, Pseudobutyrivibrio xylanivorans Mz5(T), Fibrobacter succinogenes S85 and Clostridium cellulovorans as pure and mixed cultures were used to enhance the lignocellulose degradation and elevate the biogas production. P. xylanivorans Mz5(T) was the most successful in elevating methane production (+17.8%), followed by the coculture of P. xylanivorans Mz5(T) and F. succinogenes S85 (+6.9%) and the coculture of C. cellulovorans and F. succinogenes S85 (+4.9%). Changes in microbial community structure were detected by fingerprinting techniques. Copyright © 2015 Elsevier Ltd. All rights reserved.

Continuous reduction of tellurite to recoverable tellurium nanoparticles using an upflow anaerobic sludge bed (UASB) reactor.

PubMed

Ramos-Ruiz, Adriana; Sesma-Martin, Juan; Sierra-Alvarez, Reyes; Field, Jim A

2017-01-01

According to the U.S. Department of Energy and the European Union, tellurium is a critical element needed for energy and defense technology. Thus methods are needed to recover tellurium from waste streams. The objectives of this study was to determine the feasibility of utilizing upflow anaerobic sludge bed (UASB) reactors to convert toxic tellurite (Te IV ) oxyanions to non-toxic insoluble elemental tellurium (Te 0 ) nanoparticles (NP) that are amendable to separation from aqueous effluents. The reactors were supplied with ethanol as the electron donating substrate to promote the biological reduction of Te IV . One reactor was additionally amended with the redox mediating flavonoid compound, riboflavin (RF), with the goal of enhancing the bioreduction of Te IV . Its performance was compared to a control reactor lacking RF. The continuous formation of Te 0 NPs using the UASB reactors was found to be feasible and remarkably improved by the addition of RF. The presence of this flavonoid was previously shown to enhance the conversion rate of Te IV by approximately 11-fold. In this study, we demonstrated that this was associated with the added benefit of reducing the toxic impact of Te IV towards the methanogenic consortium in the UASB and thus enabled a 4.7-fold higher conversion rate of the chemical oxygen demand. Taken as a whole, this work demonstrates the potential of a methanogenic granular sludge to be applied as a bioreactor technology producing recoverable Te 0 NPs in a continuous fashion. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of a three-phase separator configuration on the performance of an upflow anaerobic sludge bed reactor treating wastewater from a fruit-canning factory.

PubMed

Wongnoi, Rachbordin; Songkasiri, Warinthorn; Phalakornkule, Chantaraporn

2007-02-01

The objective of this study was to investigate the influence of a three-phase separator configuration on the performance of an upflow anaerobic sludge bed (USAB) treating wastewater from a fruit canning factory. The performances of two 30-L UASB reactors--one with a modified three-phase separator giving a spiral flow pattern and the other with a conventional configuration-were investigated in parallel. Wastewater, with a chemical oxygen demand (COD) concentration between 2000 and 7000 mg/L, was obtained from a fruit-canning factory. Based on the effluent data of the first 100 operation days, the UASB with the three-phase separator giving spiral flow patterns yielded up to 25% lower biomass washout. It also showed better efficiencies in treating wastewater--up to 60% lower effluent COD, up to 20% higher COD percent removal, and up to 29% higher biogas production. This work presents evidence of an improvement on the conventional physical design of a UASB.

Kinetics of anaerobic degradation of screened dairy manure by upflow fixed bed digesters: effect of natural zeolite addition.

PubMed

Nikolaeva, S; Sánchez, E; Borja, R; Raposo, F; Colmenarejo, M F; Montalvo, S; Jiménez-Rodríguez, A M

2009-02-01

The effect of the hydraulic retention time (HRT) on the performance of two up-flow anaerobic fixed bed digesters (UFAFBDs) packed with waste tire rubber (D1) and waste tire rubber and zeolite (D2) as micro-organism immobilization supports was studied. It was found that a first-order kinetic model described well the experimental results obtained. The kinetic constants for COD, BOD5, total solids (TS) and volatile solids (VS) removal were determined to be higher in digester D2 than in digester D1 or control. Specifically, they were 0.28 +/- 0.01, 0.32 +/- 0.02, 0.16 +/- 0.01 and 0.24 +/- 0.01 d(- 1) respectively for D1 and 0.33 +/- 0.02, 0.40 +/- 0.02, 0.21 +/- 0.01 and 0.28 +/- 0.01 d(- 1) respectively for D2. This was significant at the 95% confidence level. In addition, the first-order model was also adequate for assessing the effect of the HRT on the removal efficiency and methane production. Maximum methane yield and the first-order constant for methane production were determined and the results obtained were comparable with those obtained by other authors but operating at higher HRTs. Maximum methane yields and the kinetic constant for methane production were 11.1% and 29.4% higher in digester D2 than in D1.

The performance of biological anaerobic filters packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) during the restart period: effect of the C/N ratios and filter media.

PubMed

Yue, Qinyan; Han, Shuxin; Yue, Min; Gao, Baoyu; Li, Qian; Yu, Hui; Zhao, Yaqin; Qi, Yuanfeng

2009-11-01

Two lab-scale upflow biological anaerobic filters (BAF) packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) were employed to investigate effects of the C/N ratios and filter media on the BAF performance during the restart period. The results indicated that BAF could be restarted normally after one-month cease. The C/N ratio of 4.0 was the thresholds of nitrate removal and nitrite accumulation. TN removal and phosphate uptake reached the maximum value at the same C/N ratio of 5.5. Ammonia formation was also found and excreted a negative influence on TN removal, especially when higher C/N ratios were applied. Nutrients were mainly degraded within the height of 25 cm from the bottom. In addition, SFCP, as novel filter media manufactured by wastes-dewatered sludge and fly ash, represented a better potential in inhibiting nitrite accumulation, TN removal and phosphate uptake due to their special characteristics in comparison with CCP.

Review of feedstock pretreatment strategies for improved anaerobic digestion: From lab-scale research to full-scale application.

PubMed

Carrere, Hélène; Antonopoulou, Georgia; Affes, Rim; Passos, Fabiana; Battimelli, Audrey; Lyberatos, Gerasimos; Ferrer, Ivet

2016-01-01

When properly designed, pretreatments may enhance the methane potential and/or anaerobic digestion rate, improving digester performance. This paper aims at providing some guidelines on the most appropriate pretreatments for the main feedstocks of biogas plants. Waste activated sludge was firstly investigated and implemented at full-scale, its thermal pretreatment with steam explosion being most recommended as it increases the methane potential and digestion rate, ensures sludge sanitation and the heat needed is produced on-site. Regarding fatty residues, saponification is preferred for enhancing their solubilisation and bioavailability. In the case of animal by-products, this pretreatment can be optimised to ensure sterilisation, solubilisation and to reduce inhibition linked to long chain fatty acids. With regards to lignocellulosic biomass, the first goal should be delignification, followed by hemicellulose and cellulose hydrolysis, alkali or biological (fungi) pretreatments being most promising. As far as microalgae are concerned, thermal pretreatment seems the most promising technique so far. Copyright © 2015 Elsevier Ltd. All rights reserved.

Upflow fixed bed bioelectrochemical reactor for wastewater treatment applications.

PubMed

González-Gutiérrez, Linda; Frontana, Carlos; Martínez, Eduardo

2015-01-01

A cylindrical Upflow Fixed Bed Reactor (UFB-BER) with granular activated carbon, steel mesh electrodes and anaerobic microorganisms, was constructed for analyzing how hydrodynamic parameters affect the reactions involved during wastewater treatment processes for azo dye degradation. Dye removal percentage was not compromised by decreasing HRTm (99-90% upon changing HRTm from 4 to 1h in single pass mode). Using the residence time distribution method for hydrodynamic characterization, it was found that a higher dispersion in the reactor occurs for HRTm=1h, than for HRTm=4h. A kinetic analysis suggests that this dispersion effect could be associated to a higher specific reaction rate dependent on the azo dye concentration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Strategy to identify the causes and to solve a sludge granulation problem in methanogenic reactors: application to a full-scale plant treating cheese wastewater.

PubMed

Macarie, Hervé; Esquivel, Maricela; Laguna, Acela; Baron, Olivier; El Mamouni, Rachid; Guiot, Serge R; Monroy, Oscar

2017-08-26

Granulation of biomass is at the basis of the operation of the most successful anaerobic systems (UASB, EGSB and IC reactors) applied worldwide for wastewater treatment. Despite of decades of studies of the biomass granulation process, it is still not fully understood and controlled. "Degranulation/lack of granulation" is a problem that occurs sometimes in anaerobic systems resulting often in heavy loss of biomass and poor treatment efficiencies or even complete reactor failure. Such a problem occurred in Mexico in two full-scale UASB reactors treating cheese wastewater. A close follow-up of the plant was performed to try to identify the factors responsible for the phenomenon. Basically, the list of possible causes to a granulation problem that were investigated can be classified amongst nutritional, i.e. related to wastewater composition (e.g. deficiency or excess of macronutrients or micronutrients, too high COD proportion due to proteins or volatile fatty acids, high ammonium, sulphate or fat concentrations), operational (excessive loading rate, sub- or over-optimal water upflow velocity) and structural (poor hydraulic design of the plant). Despite of an intensive search, the causes of the granulation problems could not be identified. The present case remains however an example of the strategy that must be followed to identify these causes and could be used as a guide for plant operators or consultants who are confronted with a similar situation independently of the type of wastewater. According to a large literature based on successful experiments at lab scale, an attempt to artificially granulate the industrial reactor biomass through the dosage of a cationic polymer was also tested but equally failed. Instead of promoting granulation, the dosage caused a heavy sludge flotation. This shows that the scaling of such a procedure from lab to real scale cannot be advised right away unless its operability at such a scale can be demonstrated.

An Exploratory Study on the Pathways of Cr (VI) Reduction in Sulfate-reducing Up-flow Anaerobic Sludge Bed (UASB) Reactor

PubMed Central

Qian, Jin; Wei, Li; Liu, Rulong; Jiang, Feng; Hao, Xiaodi; Chen, Guang-Hao

2016-01-01

Electroplating wastewater contains both Cr (VI) and sulfate. So Cr (VI) removal under sulfate-rich condition is quite complicated. This study mainly investigates the pathways for Cr (VI) removal under biological sulfate-reducing condition in the up-flow anaerobic sludge bed (UASB) reactor. Two potential pathways are found for the removal of Cr (VI). The first one is the sulfidogenesis-induced Cr (VI) reduction pathway (for 90% Cr (VI) removal), in which Cr (VI) is reduced by sulfide generated from biological reduction of sulfate. The second one leads to direct reduction of Cr (VI) which is utilized by bacteria as the electron acceptor (for 10% Cr (VI) removal). Batch test results confirmed that sulfide was oxidized to elemental sulfur instead of sulfate during Cr (VI) reduction. The produced extracellular polymeric substances (EPS) provided protection to the microbes, resulting in effective removal of Cr (VI). Sulfate-reducing bacteria (SRB) genera accounted for 11.1% of the total bacterial community; thus they could be the major organisms mediating the sulfidogenesis-induced reduction of Cr (VI). In addition, chromate-utilizing genera (e.g. Microbacterium) were also detected, which were possibly responsible for the direct reduction of Cr (VI) using organics as the electron donor and Cr (VI) as the electron acceptor. PMID:27021522

A case study of coupling upflow anaerobic sludge blanket (UASB) and ANITA™ Mox process to treat high-strength landfill leachate.

PubMed

Lu, Ting; George, Biju; Zhao, Hong; Liu, Wenjun

2016-01-01

A pilot study was conducted to study the treatability of high-strength landfill leachate by a combined process including upflow anaerobic sludge blanket (UASB), carbon removal (C-stage) moving bed biofilm reactor (MBBR) and ANITA™ Mox process. The major innovation on this pilot study is the patent-pending process invented by Veolia that integrates the above three unit processes with an effluent recycle stream, which not only maintains the low hydraulic retention time to enhance the treatment performance but also reduces inhibiting effect from chemicals present in the high-strength leachate. This pilot study has demonstrated that the combined process was capable of treating high-strength leachate with efficient chemical oxygen demand (COD) and nitrogen removals. The COD removal efficiency by the UASB was 93% (from 45,000 to 3,000 mg/L) at a loading rate of 10 kg/(m(3)·d). The C-stage MBBR removed an additional 500 to 1,000 mg/L of COD at a surface removal rate (SRR) of 5 g/(m(2)·d) and precipitated 400 mg/L of calcium. The total inorganic nitrogen removal efficiency by the ANITA Mox reactor was about 70% at SRR of 1.0 g/(m(2)·d).

Competition and coexistence of sulfate-reducing bacteria, acetogens and methanogens in a lab-scale anaerobic bioreactor as affected by changing substrate to sulfate ratio

PubMed Central

Dar, Shabir A.; Kleerebezem, Robbert; Stams, Alfons J. M.; Kuenen, J. Gijs

2008-01-01

The microbial population structure and function of natural anaerobic communities maintained in lab-scale continuously stirred tank reactors at different lactate to sulfate ratios and in the absence of sulfate were analyzed using an integrated approach of molecular techniques and chemical analysis. The population structure, determined by denaturing gradient gel electrophoresis and by the use of oligonucleotide probes, was linked to the functional changes in the reactors. At the influent lactate to sulfate molar ratio of 0.35 mol mol−1, i.e., electron donor limitation, lactate oxidation was mainly carried out by incompletely oxidizing sulfate-reducing bacteria, which formed 80–85% of the total bacterial population. Desulfomicrobium- and Desulfovibrio-like species were the most abundant sulfate-reducing bacteria. Acetogens and methanogenic Archaea were mostly outcompeted, although less than 2% of an acetogenic population could still be observed at this limiting concentration of lactate. In the near absence of sulfate (i.e., at very high lactate/sulfate ratio), acetogens and methanogenic Archaea were the dominant microbial communities. Acetogenic bacteria represented by Dendrosporobacter quercicolus-like species formed more than 70% of the population, while methanogenic bacteria related to uncultured Archaea comprising about 10–15% of the microbial community. At an influent lactate to sulfate molar ratio of 2 mol mol−1, i.e., under sulfate-limiting conditions, a different metabolic route was followed by the mixed anaerobic community. Apparently, lactate was fermented to acetate and propionate, while the majority of sulfidogenesis and methanogenesis were dependent on these fermentation products. This was consistent with the presence of significant levels (40–45% of total bacteria) of D. quercicolus-like heteroacetogens and a corresponding increase of propionate-oxidizing Desulfobulbus-like sulfate-reducing bacteria (20% of the total bacteria). Methanogenic

Turf soil enhances treatment efficiency and performance of phenolic wastewater in an up-flow anaerobic sludge blanket reactor.

PubMed

Chen, Chunmao; Yao, Xianyang; Li, Qing X; Wang, Qinghong; Liang, Jiahao; Zhang, Simin; Ming, Jie; Liu, Zhiyuan; Deng, Jingmin; Yoza, Brandon A

2018-08-01

Phenols are industrially generated intermediate chemicals found in wastewaters that are considered a class of environmental priority pollutants. Up-flow anaerobic sludge blanket (UASB) reactors are used for phenolic wastewater treatment and exhibit high volume loading capability, favorable granule settling, and tolerance to impact loads. Use of support materials can promote biological productivity and accelerate start-up period of UASB. In the present study, turf soil was used as a support material in a mesophilic UASB reactor for the removal of phenols in wastewater. During sludge acclimatization (45-96 days), COD and phenols in the treatments were both reduced by 97%, whereas these contents in the controls were decreased by 81% and 75%, respectively. The phenol load threshold for the turf soil UASB reactor was greater (1200 mg/L, the equivalent of COD 3000 mg/L) in comparison with the control UASB reactor (900 mg/L, the equivalent of COD 2250 mg/L) and the turf soil UASB reactor was also more resistant to shock loading. Improved sludge settling, shear resistance, and higher biological activity occurred with the turf soil UASB reactor due to the formation of large granular sludge (0.6 mm or larger) in higher relative percentages. Granular sludge size was further enhanced by the colonization of filamentous bacteria on the irregular surface of the turf soil. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization and anaerobic treatment of the sanitary landfill leachate in Istanbul.

PubMed

Inanc, B; Calli, B; Saatci, A

2000-01-01

In this study, characterization and anaerobic treatability of leachate from Komurcuoda Sanitary Landfill located on the Asian part of Istanbul were investigated. Time based fluctuations in characteristics of leachate were monitored for an 8 month period. Samples were taken from a 200 m3 holding tank located at the lowest elevation of the landfill. COD concentrations have ranged between 18,800 and 47,800 mg/l while BOD5 between 6820 and 38,500 mg/L. COD and BOD5 values were higher in summer and lower in winter due to dilution by precipitation. On the other hand, it was quite interesting that such a dilution effect was not observed for ammonia. The highest ammonia concentration, 2690 mg/L was in November 1998. BOD5/COD ratio was larger than 0.7 for most samples indicating high biodegradability, and acidic phase of decomposition in the landfill. For anaerobic treatability, three different reactors, namely an upflow anaerobic sludge bed reactor, an anaerobic upflow filter and a hybrid bed reactor, were used. The anaerobic reactors were operated for more than 230 days and were continuing operation when this paper was prepared. Organic loading was increased gradually from 1.3 kg COD/m3.day to 8.2 kg COD/m3.day while hydraulic retention time was reduced from 2.4 days to 2.0 days. All the reactors showed similar performances against organic loadings with efficiencies between 80% and 90%. However the reactors have experienced high ammonia concentrations several times throughout the experimental period, and showed different inhibition levels. Anaerobic filter was the least affected reactor while UASB was the most. Hybrid bed reactor has exhibited a similar performance to anaerobic filter although not to the same degree.

Active region upflows. I. Multi-instrument observations

NASA Astrophysics Data System (ADS)

Vanninathan, K.; Madjarska, M. S.; Galsgaard, K.; Huang, Z.; Doyle, J. G.

2015-12-01

Context. We study upflows at the edges of active regions, called AR outflows, using multi-instrument observations. Aims: This study intends to provide the first direct observational evidence of whether chromospheric jets play an important role in furnishing mass that could sustain coronal upflows. The evolution of the photospheric magnetic field, associated with the footpoints of the upflow region and the plasma properties of active region upflows is investigated with the aim of providing information for benchmarking data-driven modelling of this solar feature. Methods: We spatially and temporally combine multi-instrument observations obtained with the Extreme-ultraviolet Imaging Spectrometer on board the Hinode, the Atmospheric Imaging Assembly and the Helioseismic Magnetic Imager instruments on board the Solar Dynamics Observatory and the Interferometric BI-dimensional Spectro-polarimeter installed at the National Solar Observatory, Sac Peak, to study the plasma parameters of the upflows and the impact of the chromosphere on active region upflows. Results: Our analysis shows that the studied active region upflow presents similarly to those studied previously, i.e. it displays blueshifted emission of 5-20 kms-1 in Fe xii and Fe xiii and its average electron density is 1.8 × 109 cm-3 at 1 MK. The time variation of the density is obtained showing no significant change (in a 3σ error). The plasma density along a single loop is calculated revealing a drop of 50% over a distance of ~20 000 km along the loop. We find a second velocity component in the blue wing of the Fe xii and Fe xiii lines at 105 kms-1 reported only once before. For the first time we study the time evolution of this component at high cadence and find that it is persistent during the whole observing period of 3.5 h with variations of only ±15 kms-1. We also, for the first time, study the evolution of the photospheric magnetic field at high cadence and find that magnetic flux diffusion is

Effect of thermal hydrolysis and ultrasounds pretreatments on foaming in anaerobic digesters.

PubMed

Alfaro, N; Cano, R; Fdz-Polanco, F

2014-10-01

Foam appears regularly in anaerobic digesters producing operational and safety problems. In this research, based on the operational observation at semi-industrial pilot scale where sludge pretreatment mitigated foaming in anaerobic digesters, this study aimed at evaluating any potential relationship between foaming tools applied to activated sludge at lab-scale (foam potential, foam stability and Microthrix parvicella abundance) and the experimental behavior observed in pilot scale and full-scale anaerobic digesters. The potential of thermal hydrolysis and ultrasounds for reducing foaming capacity was also evaluated. Filamentous bacteria abundance was directly linked to foaming capacity in anaerobic processes. A maximum reduction of M.parvicella abundance (from 5 to 2) was reached using thermal hydrolysis with steam explosion at 170°C and ultrasounds at 66.7kWh/m(3), showing both good anti-foaming properties. On the other hand, foam potential and stability determinations showed a lack of consistency with the bacteria abundance results and experimental evidences. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microbial community structure in a full-scale anaerobic treatment plant during start-up and first year of operation revealed by high-throughput 16S rRNA gene amplicon sequencing.

PubMed

Fykse, Else Marie; Aarskaug, Tone; Madslien, Elisabeth H; Dybwad, Marius

2016-12-01

High-throughput amplicon sequencing of six biomass samples from a full-scale anaerobic reactor at a Norwegian wood and pulp factory using Biothane Biobed Expanded Granular Sludge Bed (EGSB) technology during start-up and first year of operation was performed. A total of 106,166 16S rRNA gene sequences (V3-V5 region) were obtained. The number of operational taxonomic units (OTUs) ranged from 595 to 2472, and a total of 38 different phyla and 143 families were observed. The predominant phyla were Bacteroidetes, Chloroflexi, Firmicutes, Proteobacteria, and Spirochaetes. A more diverse microbial community was observed in the inoculum biomass coming from an Upflow Anaerobic Sludge Blanket (USAB) reactor, reflecting an adaptation of the inoculum diversity to the specific conditions of the new reactor. In addition, no taxa classified as obligate pathogens were identified and potentially opportunistic pathogens were absent or observed in low abundances. No Legionella bacteria were identified by traditional culture-based and molecular methods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of low strength industrial cluster wastewater by anaerobic hybrid reactor.

PubMed

Kumar, Amit; Yadav, Asheesh Kumar; Sreekrishnan, T R; Satya, Santosh; Kaushik, C P

2008-05-01

The study was aimed at treating the complex, combined wastewater generated in Mangolpuri industrial cluster. It was considered as a low strength wastewater with respect to its organic content. Anaerobic treatment of this wastewater was studied using an anaerobic hybrid reactor (AHR) which combined the best features of both the upflow anaerobic sludge blanket (UASB) reactor and anaerobic fluidized bed rector (AFBR). The performance of the reactor under different organic and hydraulic loading rates were studied. The COD removal reached 94% at an organic loading rate (OLR) of 2.08 kg COD m(-3)d(-1) at an hydraulic retention time (HRT) of 6.0 h. The granules developed were characterized in terms of their diameter and terminal settling velocity.

Toluene inhibition on an anaerobic reactor sludge in terms of potential activity and composition of acetoclastic methanogens.

PubMed

Ince, Orhan; Kolukirik, Mustafa; Cetecioglu, Zeynep; Eyice, Ozge; Inceoglu, Ozgul; Ince, Bahar

2009-12-01

The aim of this study was to determine the effect of toluene on an anaerobic sludge taken from a full-scale upflow anaerobic sludge blanket (UASB) reactor in terms of potential activity and composition of acetoclastic methanogens. Specific methanogenic activity (SMA) test results showed that 5%, 9.5%, 14%, 24%, 29%, 38% and 62% inhibition occurred in the potential methane production (PMP) rate of the sludge at toluene concentrations of 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM, 0.5 mM, 0.6 mM and 1 mM, respectively. Fluorescence in situ hybridization (FISH) results showed that relative abundance of archaeal cells was approx. 19% throughout the SMA tests. The anaerobic sludge was dominated by acetoclastic genus Methanosaeta which were slightly affected by increasing toluene concentrations do not have any effect on relative abundance of Methanosaeta spp., which was between 73% +/- 1.6 and 68% +/- 2.1 of the archaeal population.

Substrate removal kinetics in high-rate upflow anaerobic filters packed with low-density polyethylene media treating high-strength agro-food wastewaters.

PubMed

Rajagopal, Rajinikanth; Torrijos, Michel; Kumar, Pradeep; Mehrotra, Indu

2013-02-15

The process kinetics for two upflow anaerobic filters (UAFs) treating high strength fruit canning and cheese-dairy wastewaters as feed were investigated. The experimental unit consisted of a 10-L (effective volume) reactor filled with low-density polyethylene media. COD removal efficiencies of about 80% were recorded at the maximum OLRs of 19 and 17 g COD L(-1) d(-1) for the fruit canning and cheese-dairy wastewaters, respectively. Modified Stover-Kincannon and second-order kinetic models were applied to data obtained from the experimental studies in order to determine the substrate removal kinetics. According to Stover-Kincannon model, U(max) and K(B) values were estimated as 109.9 and 109.7 g L(-1) d(-1) for fruit canning, and 53.5 and 49.7 g L(-1) d(-1) for cheese dairy wastewaters, respectively. The second order substrate removal rate k(2(s)) was found to be 5.0 and 1.93 d(-1) respectively for fruit canning and cheese dairy wastewaters. As both these models gave high correlation coefficients (R(2) = 98-99%), they could be used in predicting the behaviour or design of the UAF. Copyright © 2012 Elsevier Ltd. All rights reserved.

Continuous removal of ore floatation reagents by an anaerobic-aerobic biological filter.

PubMed

Cheng, Huang; Lin, Hai; Huo, Hanxin; Dong, Yingbo; Xue, Qiuyu; Cao, Lixia

2012-06-01

A laboratory scale up-flow anaerobic-aerobic biological filter was constructed to treat synthetic ore floatation wastewater. Volcanic stone was applied as packing media for aerobic section. Biodegradation of some common ore floatation reagents as potassium ethyl xanthate dithiophosphate and turpentine were evaluated. An average COD reduction rate of 88.7% for potassium ethyl xanthate by the biofilter was obtained at HRT of 6h, air water flow ratio of 10:1 and pH of 7. Its effluent COD concentration varied between 17 and 43 mg/L. Xanthates and dithiophosphate were found to be easily biodegradable, whereas turpentine was not favorable for microorganism to digest. The performance of the reactor fluctuated slightly within the temperature range of 10-35 °C. Operation of the biofilter was sensitive to influent pH values. A neutral to weak basic influent was preferred for biofilter to maintain an efficient operation. Anaerobic treatment was able to enhance the biodegradability of influents significantly. Copyright © 2012 Elsevier Ltd. All rights reserved.

Artificial intelligence based model for optimization of COD removal efficiency of an up-flow anaerobic sludge blanket reactor in the saline wastewater treatment.

PubMed

Picos-Benítez, Alain R; López-Hincapié, Juan D; Chávez-Ramírez, Abraham U; Rodríguez-García, Adrián

2017-03-01

The complex non-linear behavior presented in the biological treatment of wastewater requires an accurate model to predict the system performance. This study evaluates the effectiveness of an artificial intelligence (AI) model, based on the combination of artificial neural networks (ANNs) and genetic algorithms (GAs), to find the optimum performance of an up-flow anaerobic sludge blanket reactor (UASB) for saline wastewater treatment. Chemical oxygen demand (COD) removal was predicted using conductivity, organic loading rate (OLR) and temperature as input variables. The ANN model was built from experimental data and performance was assessed through the maximum mean absolute percentage error (= 9.226%) computed from the measured and model predicted values of the COD. Accordingly, the ANN model was used as a fitness function in a GA to find the best operational condition. In the worst case scenario (low energy requirements, high OLR usage and high salinity) this model guaranteed COD removal efficiency values above 70%. This result is consistent and was validated experimentally, confirming that this ANN-GA model can be used as a tool to achieve the best performance of a UASB reactor with the minimum requirement of energy for saline wastewater treatment.

Continuously-stirred anaerobic digester to convert organic wastes into biogas: system setup and basic operation.

PubMed

Usack, Joseph G; Spirito, Catherine M; Angenent, Largus T

2012-07-13

Anaerobic digestion (AD) is a bioprocess that is commonly used to convert complex organic wastes into a useful biogas with methane as the energy carrier. Increasingly, AD is being used in industrial, agricultural, and municipal waste(water) treatment applications. The use of AD technology allows plant operators to reduce waste disposal costs and offset energy utility expenses. In addition to treating organic wastes, energy crops are being converted into the energy carrier methane. As the application of AD technology broadens for the treatment of new substrates and co-substrate mixtures, so does the demand for a reliable testing methodology at the pilot- and laboratory-scale. Anaerobic digestion systems have a variety of configurations, including the continuously stirred tank reactor (CSTR), plug flow (PF), and anaerobic sequencing batch reactor (ASBR) configurations. The CSTR is frequently used in research due to its simplicity in design and operation, but also for its advantages in experimentation. Compared to other configurations, the CSTR provides greater uniformity of system parameters, such as temperature, mixing, chemical concentration, and substrate concentration. Ultimately, when designing a full-scale reactor, the optimum reactor configuration will depend on the character of a given substrate among many other nontechnical considerations. However, all configurations share fundamental design features and operating parameters that render the CSTR appropriate for most preliminary assessments. If researchers and engineers use an influent stream with relatively high concentrations of solids, then lab-scale bioreactor configurations cannot be fed continuously due to plugging problems of lab-scale pumps with solids or settling of solids in tubing. For that scenario with continuous mixing requirements, lab-scale bioreactors are fed periodically and we refer to such configurations as continuously stirred anaerobic digesters (CSADs). This article presents a general

Anaerobic treatment of distillery spent wash - a study on upflow anaerobic fixed film bioreactor.

PubMed

Acharya, Bhavik K; Mohana, Sarayu; Madamwar, Datta

2008-07-01

Anaerobic digestion of wastewater from a distillery industry having very high COD (1,10,000-1,90,000 mg/L) and BOD (50,000-60,000 mg/L) was studied in a continuously fed, up flow fixed film column reactor using different support materials such as charcoal, coconut coir and nylon fibers under varying hydraulic retention time and organic loading rates. The seed consortium was prepared by enrichment with distillery spent wash in a conventional type reactor having working capacity of 3 L and was used for charging the anaerobic column reactor. Amongst the various support materials studied the reactor having coconut coir could treat distillery spent wash at 8d hydraulic retention time with organic loading rate of 23.25 kg COD m(-3)d(-1) leading to 64% COD reduction with biogas production of 7.2 m3 m(-3)d(-1) having high methane yield without any pretreatment or neutralization of the distillery spent wash. This study indicates fixed film biomethanation of distillery spent wash using coconut coir as the support material appears to be a cost effective and promising technology for mitigating the problems caused by distillery effluent.

VAPOR PHASE TREATMENT OF PCE IN A SOIL COLUMN BY LAB-SCALE ANAEROBIC BIOVENTING

EPA Science Inventory

Microbial destruction of highly chlorinated organic compounds must be initiated by anaerobic followed by aerobic dechlorination. In-situ dechlorination of vadose zone soil contaminated with these compounds requires, among other factors, the establishment of highly reductive anaer...

Performance evaluation of a large sewage treatment plant in Brazil, consisting of an upflow anaerobic sludge blanket reactor followed by activated sludge.

PubMed

Saliba, Pollyane Diniz; von Sperling, Marcos

2017-10-01

The objective of this study was to evaluate the behaviour of a system comprising an upflow anaerobic sludge blanket reactor followed by activated sludge to treat domestic sewage. The Betim Central sewage treatment plant, Brazil, was designed to treat a mean influent flow of 514 L/s. The study consisted of statistical treatment of monitoring data from the treatment plant covering a period of 4 years. This work presents the concentrations and removal efficiencies of the main constituents in each stage of the treatment process, and a mass balance of chemical oxygen demand (COD) and nitrogen. The results highlight the good overall performance of the system, with high mean removal efficiencies: BOD (biochemical oxygen demand) (94%), COD (91%), ammonia (72%) and total suspended solids (92%). As expected, this system was not effective for the removal of nutrients, since it was not designed for this purpose. The removal of Escherichia coli (99.83%) was higher than expected. There was no apparent influence of operational and design parameters on the effluent quality in terms of organic matter removal, with the exceptions of the BOD load upstream of the aeration tank and the sludge age in the unit. Results suggest that this system is well suited for the treatment of domestic sewage.

Simultaneous carbon and nitrogen removal using a litre-scale upflow microbial fuel cell.

PubMed

Zhao, Ling-ling; Song, Tian-shun

2014-01-01

A 10 L upflow microbial fuel cell (UMFC) was constructed for simultaneous carbon and nitrogen removal. During the 6-month operation, the UMFC constantly removed carbon and nitrogen, and then generated electricity with synthetic wastewater as substrate. At 5.0 mg L(-1) dissolved oxygen, 100 Ω external resistance, and pH 6.5, the maximum power density (Pmax) and nitrification rate for the UMFC was 19.5 mW m(-2) and 17.9 mg·(L d)(-1), respectively. In addition, Pmax in the UMFC with chicken manure wastewater as substrate was 16 mW m(-2), and a high chemical oxygen demand (COD) removal efficiency of 94.1% in the UMFC was achieved at 50 mM phosphate-buffered saline. Almost all ammonia in the cathode effluent was effectively degraded after biological denitrification in the UMFC cathode. The results can help to further develop pilot-scale microbial fuel cells for simultaneous carbon and nitrogen removal.

Modified septic tank-anaerobic filter unit as a two-stage onsite domestic wastewater treatment system.

PubMed

Sharma, Meena Kumari; Khursheed, Anwar; Kazmi, Absar Ahmad

2014-01-01

This study demonstrates the performance evaluation of a uniquely designed two-stage system for onsite treatment of domestic wastewater. The system consisted of two upflow anaerobic bioreactors, a modified septic tank followed by an upflow anaerobic filter, accommodated within a single cylindrical unit. The system was started up without inoculation at 24 h hydraulic retention time (HRT). It achieved a steady-state condition after 120 days. The system was observed to be remarkably efficient in removing pollutants during steady-state condition with the average removal efficiency of 88.6 +/- 3.7% for chemical oxygen demand, 86.3 +/- 4.9% for biochemical oxygen demand and 91.2 +/- 9.7% for total suspended solids. The microbial analysis revealed a high reduction (>90%) capacity of the system for indicator organism and pathogens. It also showed a very good endurance against imposed hydraulic shock load. Tracer study showed that the flow pattern was close to plug flow reactor. Mean HRT was also found to be close to the designed value.

Modeling microbial diversity in anaerobic digestion through an extended ADM1 model.

PubMed

Ramirez, Ivan; Volcke, Eveline I P; Rajinikanth, Rajagopal; Steyer, Jean-Philippe

2009-06-01

The anaerobic digestion process comprises a whole network of sequential and parallel reactions, of both biochemical and physicochemical nature. Mathematical models, aiming at understanding and optimization of the anaerobic digestion process, describe these reactions in a structured way, the IWA Anaerobic Digestion Model No. 1 (ADM1) being the most well established example. While these models distinguish between different microorganisms involved in different reactions, to our knowledge they all neglect species diversity between organisms with the same function, i.e. performing the same reaction. Nevertheless, available experimental evidence suggests that the structure and properties of a microbial community may be influenced by process operation and on their turn also determine the reactor functioning. In order to adequately describe these phenomena, mathematical models need to consider the underlying microbial diversity. This is demonstrated in this contribution by extending the ADM1 to describe microbial diversity between organisms of the same functional group. The resulting model has been compared with the traditional ADM1 in describing experimental data of a pilot-scale hybrid Upflow Anaerobic Sludge Filter Bed (UASFB) reactor, as well as in a more detailed simulation study. The presented model is further shown useful in assessing the relationship between reactor performance and microbial community structure in mesophilic CSTRs seeded with slaughterhouse wastewater when facing increasing levels of ammonia.

Candidatus Accumulibacter phosphatis clades enriched under cyclic anaerobic and microaerobic conditions simultaneously use different electron acceptors

EPA Science Inventory

Lab- and pilot-scale simultaneous nitrification, denitrification and phosphorus removal-sequencing batch reactors were operated under cyclic anaerobic and micro-aerobic conditions. The use of oxygen, nitrite, and nitrate as electron acceptors by Candidatus Accumulibacter phosphat...

Virus removal retention challenge tests performed at lab scale and pilot scale during operation of membrane units.

PubMed

Humbert, H; Machinal, C; Labaye, Ivan; Schrotter, J C

2011-01-01

The determination of the virus retention capabilities of UF units during operation is essential for the operators of drinking water treatment facilities in order to guarantee an efficient and stable removal of viruses through time. In previous studies, an effective method (MS2-phage challenge tests) was developed by the Water Research Center of Veolia Environnement for the measurement of the virus retention rates (Log Removal Rate, LRV) of commercially available hollow fiber membranes at lab scale. In the present work, the protocol for monitoring membrane performance was transferred from lab scale to pilot scale. Membrane performances were evaluated during pilot trial and compared to the results obtained at lab scale with fibers taken from the pilot plant modules. PFU culture method was compared to RT-PCR method for the calculation of LRV in both cases. Preliminary tests at lab scale showed that both methods can be used interchangeably. For tests conducted on virgin membrane, a good consistency was observed between lab and pilot scale results with the two analytical methods used. This work intends to show that a reliable determination of the membranes performances based on RT-PCR analytical method can be achieved during the operation of the UF units.

COMMERCIAL-SCALE AEROBIC-ANAEROBIC BIOREACTOR LANDFILL OPERATIONS

EPA Science Inventory

A sequential aerobic-anaerobic treatment system has been applied at a commercial scale (3,000 ton per day) municipal solid waste landfill in Kentucky, USA since 2001. In this system, the uppermost layer of landfilled waste is aerated and liquid waste including leachate, surface w...

Effects of different nitrogen sources on the biogas production - a lab-scale investigation.

PubMed

Wagner, Andreas Otto; Hohlbrugger, Peter; Lins, Philipp; Illmer, Paul

2012-12-20

For anaerobic digestion processes nitrogen sources are poorly investigated although they are known as possible process limiting factors (in the hydrolysis phase) but also as a source for fermentations for subsequent methane production by methanogenic archaea. In the present study different complex and defined nitrogen sources were investigated in a lab-scale experiment in order to study their potential to build up methane. The outcome of the study can be summarised as follows: from complex nitrogen sources yeast extract and casamino acids showed the highest methane production with approximately 600 ml methane per mole of nitrogen, whereas by the use of skim milk no methane production could be observed. From defined nitrogen sources L-arginine showed the highest methane production with almost 1400 ml methane per mole of nitrogen. Moreover it could be demonstrated that the carbon content and therefore C/N-ratio has only minor influence for the methane production from the used substrates. Copyright © 2011 Elsevier GmbH. All rights reserved.

Determination and Variation of Core Bacterial Community in a Two-Stage Full-Scale Anaerobic Reactor Treating High-Strength Pharmaceutical Wastewater.

PubMed

Ma, Haijun; Ye, Lin; Hu, Haidong; Zhang, Lulu; Ding, Lili; Ren, Hongqiang

2017-10-28

Knowledge on the functional characteristics and temporal variation of anaerobic bacterial populations is important for better understanding of the microbial process of two-stage anaerobic reactors. However, owing to the high diversity of anaerobic bacteria, close attention should be prioritized to the frequently abundant bacteria that were defined as core bacteria and putatively functionally important. In this study, using MiSeq sequencing technology, the core bacterial community of 98 operational taxonomic units (OTUs) was determined in a two-stage upflow blanket filter reactor treating pharmaceutical wastewater. The core bacterial community accounted for 61.66% of the total sequences and accurately predicted the sample location in the principal coordinates analysis scatter plot as the total bacterial OTUs did. The core bacterial community in the first-stage (FS) and second-stage (SS) reactors were generally distinct, in that the FS core bacterial community was indicated to be more related to a higher-level fermentation process, and the SS core bacterial community contained more microbes in syntrophic cooperation with methanogens. Moreover, the different responses of the FS and SS core bacterial communities to the temperature shock and influent disturbance caused by solid contamination were fully investigated. Co-occurring analysis at the Order level implied that Bacteroidales, Selenomonadales, Anaerolineales, Syneristales, and Thermotogales might play key roles in anaerobic digestion due to their high abundance and tight correlation with other microbes. These findings advance our knowledge about the core bacterial community and its temporal variability for future comparative research and improvement of the two-stage anaerobic system operation.

Lab-scale co-digestion of kitchen waste and brown water for a preliminary performance evaluation of a decentralized waste and wastewater management.

PubMed

Lavagnolo, Maria Cristina; Girotto, Francesca; Hirata, Osamu; Cossu, Raffaello

2017-08-01

An overall interaction is manifested between wastewater and solid waste management schemes. At the Laboratory of Environmental Engineering (LISA) of the University of Padova, Italy, the scientific and technical implications of putting into practice a decentralized waste and wastewater treatment based on the separation of grey water, brown water (BW - faecal matter) and yellow water (YW - urine) are currently undergoing investigation in the Aquanova Project. An additional aim of this concept is the source segregation of kitchen waste (KW) for subsequent anaerobic co-digestion with BW. To determine an optimal mixing ratio and temperature for use in the treatment of KW, BW, and eventually YW, by means of anaerobic digestion, a series of lab-scale batch tests were performed. Organic mixtures of KW and BW performed much better (max. 520mlCH 4 /gVS) in terms of methane yields than the individual substrates alone (max. 220mlCH 4 /gVS). A small concentration of urine proved to have a positive effect on anaerobic digestion performance, possibly due to the presence of micronutrients in YW. When considering high YW concentrations in the anaerobically digested mixtures, no ammonia inhibition was observed until a 30% and 10% YW content was added under mesophilic and thermophilic conditions, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Electron Densities in Solar Flare Loops, Chromospheric Evaporation Upflows, and Acceleration Sites

NASA Technical Reports Server (NTRS)

Aschwanden, Markus J.; Benz, Arnold O.

1996-01-01

We compare electron densities measured at three different locations in solar flares: (1) in Soft X-Ray (SXR) loops, determined from SXR emission measures and loop diameters from Yohkoh Soft X-Ray Telescope maps (n(sub e, sup SXR) = (0.2-2.5) x 10(exp 11)/ cu cm); (2) in chromospheric evaporation upflows, inferred from plasma frequency cutoffs of decimetric radio bursts detected with the 0.1-3 GHz spectrometer Phoenix of ETH Zuerich (n(sub e, sup upflow) = (0.3-11) x 10(exp 10)/cu cm; and (3) in acceleration sites, inferred from the plasma frequency at the separatrix between upward-accelerated (type III bursts) and downward-accelerated (reverse-drift bursts) electron beams [n(sub e, sup acc) = (0.6-10) x 10(exp 9)/cu cm]. The comparison of these density measurements, obtained from 44 flare episodes (during 14 different flares), demonstrates the compatibility of flare plasma density diagnostics with SXR and radio methods. The density in the upflowing plasma is found to be somewhat lower than in the filled loops, having ratios in a range n(sub e, sup upflow)/n(sub e, sup SXR) = 0.02-1.3, and a factor of 3.6 higher behind the upflow front. The acceleration sites are found to have a much lower density than the SXR-bright flare loops, i.e., n(sub e, sup acc)/n(sub e, sup SXR) = 0.005- 0.13, and thus must be physically displaced from the SXR-bright flare loops. The scaling law between electron time-of-flight distances l' and loop half-lengths s, l'/s = 1.4 +/- 0.3, recently established by Aschwanden et al. suggests that the centroid of the acceleration region is located above the SXR-bright flare loop, as envisioned in cusp geometries (e.g., in magnetic reconnection models).

Anaerobic Treatment of Palm Oil Mill Effluent in Pilot-Scale Anaerobic EGSB Reactor

PubMed Central

Mahmood, Qaisar; Qiu, Jiang-Ping; Li, Yin-Sheng; Chang, Yoon-Seong; Li, Xu-Dong

2015-01-01

Large volumes of untreated palm oil mill effluent (POME) pose threat to aquatic environment due to the presence of very high organic content. The present investigation involved two pilot-scale anaerobic expanded granular sludge bed (EGSB) reactors, continuously operated for 1 year to treat POME. Setting HRT at 9.8 d, the anaerobic EGSB reactors reduced COD from 71179 mg/L to 12341 mg/L and recycled half of sludge by a dissolved air flotation (DAF). The average effluent COD was 3587 mg/L with the consistent COD removal efficiency of 94.89%. Adding cationic polymer (PAM) dose of 30 mg/L to DAF unit and recycling its half of sludge caused granulation of anaerobic sludge. Bacilli and small coccid bacteria were the dominant microbial species of the reactor. The reactor produced 27.65 m3 of biogas per m3 of POME which was utilized for electricity generation. PMID:26167485

Grey water treatment in a series anaerobic--aerobic system for irrigation.

PubMed

Abu Ghunmi, Lina; Zeeman, Grietje; Fayyad, Manar; van Lier, Jules B

2010-01-01

This study aims at treatment of grey water for irrigation, focusing on a treatment technology that is robust, simple to operate and with minimum energy consumption. The result is an optimized system consisting of an anaerobic unit operated in upflow mode, with a 1 day operational cycle, a constant effluent flow rate and varying liquid volume. Subsequent aerobic step is equipped with mechanical aeration and the system is insulated for sustaining winter conditions. The COD removal achieved by the anaerobic and aerobic units in summer and winter are 45%, 39% and 53%, 64%, respectively. Sludge in the anaerobic and aerobic reactor has a concentration of 168 and 8 mg VSL(-1), respectively. Stability of sludge in the anaerobic and aerobic reactors is 80% and 93%, respectively, based on COD. Aerobic effluent quality, except for pathogens, agrees with the proposed irrigation water quality guidelines for reclaimed water in Jordan.

Plasma characteristics of upflowing ion beams in the polar cap region

NASA Technical Reports Server (NTRS)

Chen, M. W.; Ashour-Abdalla, M.; Peterson, W. K.; Moore, T. E.; Persoon, A. M.

1990-01-01

The plasma characteristics of upflowing ion stream events with energies greater than 10 eV in the polar cap region near solar maximum are analyzed. It is found that, in 22 of the 41 polar ion streaming events studied, O(+) is the dominant ion constituent in the upflowing beam components. There are significant amounts of upflowing O(+) in the plasma even during quiet auroral conditions. In one event, the upflowing O(+) population had two components, a cold distribution and a warm one. In another event the O(+) and H(+) temperatures suggested that ionospheric ions are heated. The cold upflowing ion stream component observed in some of the polar ion streaming events exhibited a filamentary nature. A significant amount of He(+) was also found in some of the events studied.

Immobilization patterns and dynamics of acetate-utilizing methanogens immobilized in sterile granular sludge in upflow anaerobic sludge blanket reactors.

PubMed

Schmidt, J E; Ahring, B K

1999-03-01

Sterile granular sludge was inoculated with either Methanosarcina mazeii S-6, Methanosaeta concilii GP-6, or both species in acetate-fed upflow anaerobic sludge blanket (UASB) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. After several months of reactor operation, the methanogens were immobilized, either separately or together. The fastest immobilization was observed in the reactor containing M. mazeii S-6. The highest effluent concentration of acetate was observed in the reactor with only M. mazeii S-6 immobilized, while the lowest effluent concentration of acetate was observed in the reactor where both types of methanogens were immobilized together. No changes were observed in the kinetic parameters (Ks and mumax) of immobilized M. concilii GP-6 or M. mazeii S-6 compared with suspended cultures, indicating that immobilization does not affect the growth kinetics of these methanogens. An enzyme-linked immunosorbent assay using polyclonal antibodies against either M. concilii GP-6 or M. mazeii S-6 showed significant variations in the two methanogenic populations in the different reactors. Polyclonal antibodies were further used to study the spatial distribution of the two methanogens. M. concilii GP-6 was immobilized only on existing support material without any specific pattern. M. mazeii S-6, however, showed a different immobilization pattern: large clumps were formed when the concentration of acetate was high, but where the acetate concentration was low this strain was immobilized on support material as single cells or small clumps. The data clearly show that the two aceticlastic methanogens immobilize differently in UASB systems, depending on the conditions found throughout the UASB reactor.

Microbial dynamics in upflow anaerobic sludge blanket (UASB) bioreactor granules in response to short-term changes in substrate feed

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

Kovacik, William P.; Scholten, Johannes C.; Culley, David E.

2010-08-01

The complexity and diversity of the microbial communities in biogranules from an upflow anaerobic sludge blanket (UASB) bioreactor were determined in response to short-term changes in substrate feeds. The reactor was fed simulated brewery wastewater (SBWW) (70% ethanol, 15% acetate, 15% propionate) for 1.5 months (phase 1), acetate / sulfate for 2 months (phase 2), acetate-alone for 3 months (phase 3), and then a return to SBWW for 2 months (phase 4). Performance of the reactor remained relatively stable throughout the experiment as shown by COD removal and gas production. 16S rDNA, methanogen-associated mcrA and sulfate reducer-associated dsrAB genes weremore » PCR amplified, then cloned and sequenced. Sequence analysis of 16S clone libraries showed a relatively simple community composed mainly of the methanogenic Archaea (Methanobacterium and Methanosaeta), members of the Green Non-Sulfur (Chloroflexi) group of Bacteria, followed by fewer numbers of Syntrophobacter, Spirochaeta, Acidobacteria and Cytophaga-related Bacterial sequences. Methanogen-related mcrA clone libraries were dominated throughout by Methanobacter and Methanospirillum related sequences. Although not numerous enough to be detected in our 16S rDNA libraries, sulfate reducers were detected in dsrAB clone libraries, with sequences related to Desulfovibrio and Desulfomonile. Community diversity levels (Shannon-Weiner index) generally decreased for all libraries in response to a change from SBWW to acetate-alone feed. But there was a large transitory increase noted in 16S diversity at the two-month sampling on acetate-alone, entirely related to an increase in Bacterial diversity. Upon return to SBWW conditions in phase 4, all diversity measures returned to near phase 1 levels.« less

Immobilization Patterns and Dynamics of Acetate-Utilizing Methanogens Immobilized in Sterile Granular Sludge in Upflow Anaerobic Sludge Blanket Reactors

PubMed Central

Schmidt, Jens Ejbye; Ahring, Birgitte Kjær

1999-01-01

Sterile granular sludge was inoculated with either Methanosarcina mazeii S-6, Methanosaeta concilii GP-6, or both species in acetate-fed upflow anaerobic sludge blanket (UASB) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. After several months of reactor operation, the methanogens were immobilized, either separately or together. The fastest immobilization was observed in the reactor containing M. mazeii S-6. The highest effluent concentration of acetate was observed in the reactor with only M. mazeii S-6 immobilized, while the lowest effluent concentration of acetate was observed in the reactor where both types of methanogens were immobilized together. No changes were observed in the kinetic parameters (Ks and μmax) of immobilized M. concilii GP-6 or M. mazeii S-6 compared with suspended cultures, indicating that immobilization does not affect the growth kinetics of these methanogens. An enzyme-linked immunosorbent assay using polyclonal antibodies against either M. concilii GP-6 or M. mazeii S-6 showed significant variations in the two methanogenic populations in the different reactors. Polyclonal antibodies were further used to study the spatial distribution of the two methanogens. M. concilii GP-6 was immobilized only on existing support material without any specific pattern. M. mazeii S-6, however, showed a different immobilization pattern: large clumps were formed when the concentration of acetate was high, but where the acetate concentration was low this strain was immobilized on support material as single cells or small clumps. The data clearly show that the two aceticlastic methanogens immobilize differently in UASB systems, depending on the conditions found throughout the UASB reactor. PMID:10049862

Lab-scale evaluation of aerated burial concept for treatment and emergency disposal of infectious animal carcasses.

PubMed

Koziel, Jacek A; Ahn, Heekwon; Glanville, Thomas D; Frana, Timothy S; van Leeuwen, J Hans; Nguyen, Lam T

2018-06-01

Nearly 55,000 outbreaks of animal disease were reported to the World Animal Health Information Database between 2005 and 2016. To suppress the spread of disease, large numbers of animal mortalities often must be disposed of quickly and are frequently buried on the farm where they were raised. While this method of emergency disposal is fast and relatively inexpensive, it also can have undesirable and lasting impacts (slow decay, concerns about groundwater contamination, pathogens re-emergence, and odor). Following the 2010 foot-and-mouth disease outbreak, the Republic of Korea's National Institute of Animal Science funded research on selected burial alternatives or modifications believed to have potential to reduce undesirable impacts of burial. One such modification involves the injection of air into the liquid degradation products from the 60-70% water from decomposing carcasses in lined burial trenches. Prior to prototype development in the field, a laboratory-scale study of aerated decomposition (AeD) of poultry carcasses was conducted to quantify improvements in time of carcass decomposition, reduction of potential groundwater pollutants in the liquid products of decomposition (since trench liners may ultimately leak), and reduction of odorous VOCs emitted during decomposition. Headspace gases also were monitored to determine the potential for using gaseous biomarkers in the aerated burial trench exhaust stream to monitor completion of the decomposition. Results of the lab-scale experiments show that the mass of chicken carcasses was reduced by 95.0 ± 0.9% within 3 months at mesophilic temperatures (vs. negligible reduction via mesophilic anaerobic digestion typical of trench burial) with concomitant reduction of biochemical oxygen demand (BOD; 99%), volatile suspended solids (VSS; 99%), total suspended solids (TSS; 99%), and total ammonia nitrogen (TAN; 98%) in the liquid digestate. At week #7 BOD and TSS in digestate met the U.S. EPA standards for

Geomagnetic and solar activity dependence of ionospheric upflowing O+: FAST observations

NASA Astrophysics Data System (ADS)

Zhao, K.; Jiang, Y.; Chen, K. W.; Huang, L. F.

2016-09-01

This paper investigates the dependence of the occurrence frequency of ionospheric upflowing oxygen (O+) ions on the sunspot cycle and geomagnetic activity. We examine the upflows response to the geomagnetic disturbances as well as the influence of the ion energy factor in controlling the magnitude of the occurrence frequency and the net energy flux. We discuss the spatial distribution of the upflow occurrence frequency and construct a regression model as a function of the magnetic latitude. The results show an overall enhancement of the upflow occurrence frequency during magnetically disturbed periods and indicate that the high-occurrence area spreads out from the source regions during magnetically quiet periods. The high-occurrence areas are located at 70° magnetic latitude (mLat) in the dayside auroral oval zone and between 76-80° mLat in the dayside polar cusp region. In the nightside auroral oval zone, these areas are near 60° mLat, penetrating further equatorward to 55° mLat during magnetically disturbed periods. High energy (≥1 keV) upflowing ions are common in the nightside auroral oval zone while low energy (<1 keV) upflowing ions are found escaping from the high latitude dayside cusp region. A Gaussian function is shown to be a good fit to the occurrence frequency over the magnetic latitude. For high energy upflowing O+ ions, the occurrence frequency exhibits a single peak located at about 60° mLat in the nightside auroral oval zone while for low energy upflowing O+ ions, it exhibits two peaks, one near 60° mLat in the auroral oval zone and the other near 78° mLat in the cusp region. We study the solar activity dependence by analyzing the relationship between the upflow occurrence frequency and the sunspot number (RZ). The statistical result shows that the frequency decreases with declining solar activity level, from ˜30 % at solar maximum to ˜5 % at solar minimum. In addition, the correlation coefficient between the occurrence frequency and RZ

Community analysis of a full-scale anaerobic bioreactor treating paper mill wastewater.

PubMed

Roest, Kees; Heilig, Hans G H J; Smidt, Hauke; de Vos, Willem M; Stams, Alfons J M; Akkermans, Antoon D L

2005-03-01

To get insight into the microbial community of an Upflow Anaerobic Sludge Blanket reactor treating paper mill wastewater, conventional microbiological methods were combined with 16S rRNA gene analyses. Particular attention was paid to microorganisms able to degrade propionate or butyrate in the presence or absence of sulphate. Serial enrichment dilutions allowed estimating the number of microorganisms per ml sludge that could use butyrate with or without sulphate (10(5)), propionate without sulphate (10(6)), or propionate and sulphate (10(8)). Quantitative RNA dot-blot hybridisation indicated that Archaea were two-times more abundant in the microbial community of anaerobic sludge than Bacteria. The microbial community composition was further characterised by 16S rRNA-gene-targeted Denaturing Gradient Gel Electrophoresis (DGGE) fingerprinting, and via cloning and sequencing of dominant amplicons from the bacterial and archaeal patterns. Most of the nearly full length (approximately 1.45 kb) bacterial 16S rRNA gene sequences showed less than 97% similarity to sequences present in public databases, in contrast to the archaeal clones (approximately. 1.3 kb) that were highly similar to known sequences. While Methanosaeta was found as the most abundant genus, also Crenarchaeote-relatives were identified. The microbial community was relatively stable over a period of 3 years (samples taken in July 1999, May 2001, March 2002 and June 2002) as indicated by the high similarity index calculated from DGGE profiles (81.9+/-2.7% for Bacteria and 75.1+/-3.1% for Archaea). 16S rRNA gene sequence analysis indicated the presence of unknown and yet uncultured microorganisms, but also showed that known sulphate-reducing bacteria and syntrophic fatty acid-oxidising microorganisms dominated the enrichments.

Nitrogen pools and flows during lab-scale degradation of old landfilled waste under different oxygen and water regimes.

PubMed

Brandstätter, Christian; Laner, David; Fellner, Johann

2015-09-01

Nitrogen emissions from municipal solid waste (MSW) landfills occur primarily via leachate, where they pose a long-term pollution problem in the form of ammonium. In-situ aeration was proposed as a remediation measure to mitigate nitrogenous landfill emissions, turning the anaerobic environment to anoxic and subsequently aerobic. As in-depth studies of the nitrogen cycle during landfill aeration had been largely missing, it was the aim of this work to establish a detailed nitrogen balance for aerobic and anaerobic degradation of landfilled MSW based on lab-scale experiments, and also investigating the effect of different water regimes on nitrogen transformation during aeration. Six landfill simulation reactors were operated in duplicate under different conditions: aerated wet (with water addition and recirculation), aerated dry (without water addition) and anaerobic (wet). The results showed that more than 78 % of the initial total nitrogen (TNinit) remained in the solids in all set ups, with the highest nitrogen losses achieved with water addition during aeration. In this case, gaseous nitrogen losses (as N2 due to denitrification) amounted up to 16.6 % of TNinit and around 4 % of TNinit was discharged via leachate. The aerated dry set-up showed lower denitrification rates (2.6-8.8 % of TNinit was released as N2), but was associated with the highest N2O emissions (3.8-3.9 % of TNinit). For the anaerobic treatment the main pathway of nitrogen discharge was the leachate, where NH4 accounted for around 8 % of TNinit. These findings provide the basis for improved management strategies to enhance nitrogen removal during in-situ aeration of old landfills.

From lab to full-scale ultrafiltration in microalgae harvesting

NASA Astrophysics Data System (ADS)

Wenten, I. G.; Steven, S.; Dwiputra, A.; Khoiruddin; Hakim, A. N.

2017-07-01

Ponding system is generally used for microalgae cultivation. However, selection of appropriate technology for the harvesting process is challenging due to the low cell density of cultivated microalgae from the ponding system and the large volume of water to be handled. One of the promising technologies for microalgae harvesting is ultrafiltration (UF). In this study, the performance of UF during harvesting of microalgae in a lab- and a full-scale test is investigated. The performances of both scales are compared and analyzed to provide an understanding of several aspects which affect the yield produced from lab and actual conditions. Furthermore, a unique self-standing non-modular UF is introduced in the full-scale test. The non-modular UF exhibits several advantages, such as simple piping and connection, single pump for filtration and backwashing, and smaller footprint. With those advantages, the non-modular UF could be a promising technology for microalgae harvesting in industrial-scale.

Heavy metal removal from synthetic wastewaters in an anaerobic bioreactor using stillage from ethanol distilleries as a carbon source.

PubMed

Gonçalves, M M M; da Costa, A C A; Leite, S G F; Sant'Anna, G L

2007-11-01

This work was conducted to investigate the possibility of using stillage from ethanol distilleries as substrate for sulfate reducing bacteria (SRB) growth and to evaluate the removal efficiency of heavy metals present in wastewaters containing sulfates. The experiments were carried out in a continuous bench-scale Upflow Anaerobic Sludge Blanket reactor (13 l) operated with a hydraulic retention time of 18 h. The bioreactor was inoculated with 7 l of anaerobic sludge. Afterwards, an enrichment procedure to increase SRB numbers was started. After this, cadmium and zinc were added to the synthetic wastewater, and their removal as metal sulfide was evaluated. The synthetic wastewater used represented the drainage from a dam of a metallurgical industry to which a carbon source (stillage) was added. The results showed that high percentages of removal (>99%) of Cd and Zn were attained in the bioreactor, and that the removal as sulfide precipitates was not the only form of metal removal occurring in the bioreactor environment.

Anaerobic digestibility of marine microalgae Phaeodactylum tricornutum in a lab-scale anaerobic membrane bioreactor.

PubMed

Zamalloa, Carlos; De Vrieze, Jo; Boon, Nico; Verstraete, Willy

2012-01-01

The biomass of industrially grown Phaeodactylum tricornutum was subjected in a novel way to bio-methanation at 33°C, i.e., in an anaerobic membrane bioreactor (AnMBR) at a hydraulic retention time of 2.5 days, at solid retention times of 20 to 10 days and at loading rates in the range of 2.6-5.9 g biomass-COD L(-1) day(-1) with membrane fluxes ranging from 1 to 0.8 L m(-2) h(-1). The total COD recovered as biogas was in the order of 52%. The input suspension was converted to a clear effluent rich in total ammonium nitrogen (546 mg TAN L(-1)) and phosphate (141 mg PO(4)-P L(-1)) usable as liquid fertilizer. The microbial community richness, dynamics, and organization in the reactor were interpreted using the microbial resource management approach. The AnMBR communities were found to be moderate in species richness and low in dynamics and community organization relative to UASB and conventional CSTR sludges. Quantitative polymerase chain reaction analysis revealed that Methanosaeta sp. was the dominant acetoclastic methanogen species followed by Methanosarcina sp. This work demonstrated that the use of AnMBR for the digestion of algal biomass is possible. The fact that some 50% of the organic matter is not liquefied means that the algal particulates in the digestate constitute a considerable fraction which should be valorized properly, for instance as slow release organic fertilizer. Overall, 1 kg of algae dry matter (DM) could be valorized in the form of biogas ( euro 2.07), N and P in the effluent (euro 0.02) and N and P in the digestate (euro 0.04), thus totaling about euro 2.13 per kilogram algae DM.

Complete Genome Sequence of a New Firmicutes Species Isolated from Anaerobic Biomass Hydrolysis.

PubMed

Abendroth, Christian; Hahnke, Sarah; Codoñer, Francisco M; Klocke, Michael; Luschnig, Olaf; Porcar, Manuel

2017-10-05

A new Firmicutes isolate, strain HV4-6-A5C, was obtained from the hydrolysis stage of a mesophilic and anaerobic two-stage lab-scale leach-bed system for biomethanation of fresh grass. It is assumed that the bacterial isolate contributes to plant biomass degradation. Here, we report a draft annotated genome sequence of this organism. Copyright © 2017 Abendroth et al.

Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes

NASA Astrophysics Data System (ADS)

Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

2010-06-01

Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex "roll-up" of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) "optical flow" code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s-1, which is supersonic for a ~10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s-1. Typical lifetimes range from 300 to 1000 s (~5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km2 s-1 reaching maximum projected areas from 2 to 15 Mm2. Maximum contrast of the dark flows relative to the bright prominence plasma in SOT images

QUIESCENT PROMINENCE DYNAMICS OBSERVED WITH THE HINODE SOLAR OPTICAL TELESCOPE. I. TURBULENT UPFLOW PLUMES

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

Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal

2010-06-20

Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) 'arches' or 'bubbles' that 'inflate' from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate verticallymore » from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex 'roll-up' of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) 'optical flow' code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s{sup -1}, which is supersonic for a {approx}10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s{sup -1}. Typical lifetimes range from 300 to 1000 s ({approx}5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km{sup 2} s{sup -1} reaching maximum projected areas from 2 to 15 Mm{sup 2}. Maximum contrast of the dark flows

Multiplexed chemostat system for quantification of biodiversity and ecosystem functioning in anaerobic digestion

PubMed Central

Plouchart, Diane; Guizard, Guillaume; Latrille, Eric

2018-01-01

Continuous cultures in chemostats have proven their value in microbiology, microbial ecology, systems biology and bioprocess engineering, among others. In these systems, microbial growth and ecosystem performance can be quantified under stable and defined environmental conditions. This is essential when linking microbial diversity to ecosystem function. Here, a new system to test this link in anaerobic, methanogenic microbial communities is introduced. Rigorously replicated experiments or a suitable experimental design typically require operating several chemostats in parallel. However, this is labor intensive, especially when measuring biogas production. Commercial solutions for multiplying reactors performing continuous anaerobic digestion exist but are expensive and use comparably large reactor volumes, requiring the preparation of substantial amounts of media. Here, a flexible system of Lab-scale Automated and Multiplexed Anaerobic Chemostat system (LAMACs) with a working volume of 200 mL is introduced. Sterile feeding, biomass wasting and pressure monitoring are automated. One module containing six reactors fits the typical dimensions of a lab bench. Thanks to automation, time required for reactor operation and maintenance are reduced compared to traditional lab-scale systems. Several modules can be used together, and so far the parallel operation of 30 reactors was demonstrated. The chemostats are autoclavable. Parameters like reactor volume, flow rates and operating temperature can be freely set. The robustness of the system was tested in a two-month long experiment in which three inocula in four replicates, i.e., twelve continuous digesters were monitored. Statistically significant differences in the biogas production between inocula were observed. In anaerobic digestion, biogas production and consequently pressure development in a closed environment is a proxy for ecosystem performance. The precision of the pressure measurement is thus crucial. The

Microthrix parvicella and Gordona amarae in mesophilic and thermophilic anaerobic digestion systems.

PubMed

Marneri, Matina; Mamais, Daniel; Koutsiouki, Efi

2009-04-14

The scope of the study presented in this paper is to determine the fate of the filamentous bacteria Gordona amarae and Microthrix parvicella in anaerobic digestion operating under mesophilic and thermophilic conditions. In order to detect and quantify foaming bacteria in the anaerobic digesters, a fluorescent in situ hybridization (FISH) method was developed and applied. This paper presents the results of a laboratory-scale study that involved the operation of four lab-scale anaerobic digestion systems operating in the mesophilic (35 degrees C) and thermophilic (55 degrees C) temperature ranges at 20 days' detention time. According to the FISH counts of G. amarae and M. parvicella, it appears that thermophilic conditions resulted in a higher destruction of both filamentous bacteria, averaging approximately 97% and 94% for the single thermophilic digester and the dual thermophilic/mesophilic system, respectively. Within the context of this study, the overall performance of the four different anaerobic digestion systems was evaluated in terms of biogas production per mass of volatile solids destroyed, COD destruction, sludge dewaterability and foaming characteristics. The dual stage systems used in this study outperformed the single stage digesters.

Comparison between lab- and full-scale applications of in situ aeration of an old landfill and assessment of long-term emission development after completion

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

Hrad, Marlies; Gamperling, Oliver; Huber-Humer, Marion, E-mail: marion.huber-humer@boku.ac.at

Highlights: ► Current data on in situ aeration effects from the first Austrian full-scale case study. ► Data on lasting waste stabilisation after aeration completion. ► Information on the transferability of results from lab- to full-scale aeration. - Abstract: Sustainable landfilling has become a fundamental objective in many modern waste management concepts. In this context, the in situ aeration of landfills has been recognised for its potential to convert conventional anaerobic landfills into biological stabilised state, whereby both current and potential (long-term) emissions of the landfilled waste are mitigated. In recent years, different in situ aeration concepts have been successfullymore » applied in Europe, North America and Asia, all pursuing different objectives and strategies. In Austria, the first full-scale application of in situ landfill aeration by means of low pressure air injection and simultaneous off-gas collection and treatment was implemented on an old, small municipal solid waste (MSW) landfill (2.6 ha) in autumn 2007. Complementary laboratory investigations were conducted with waste samples taken from the landfill site in order to provide more information on the transferability of the results from lab- to full-scale aeration measures. In addition, long-term emission development of the stabilised waste after aeration completion was assessed in an ongoing laboratory experiment. Although the initial waste material was described as mostly stable in terms of the biological parameters gas generation potential over 21 days (GP{sub 21}) and respiration activity over 4 days (RA{sub 4}), the lab-scale experiments indicated that aeration, which led to a significant improvement of leachate quality, was accompanied by further measurable changes in the solid waste material under optimised conditions. Even 75 weeks after aeration completion the leachate, as well as gaseous emissions from the stabilised waste material, remained low and stayed below

Novel online monitoring and alert system for anaerobic digestion reactors.

PubMed

Dong, Fang; Zhao, Quan-Bao; Li, Wen-Wei; Sheng, Guo-Ping; Zhao, Jin-Bao; Tang, Yong; Yu, Han-Qing; Kubota, Kengo; Li, Yu-You; Harada, Hideki

2011-10-15

Effective monitoring and diagnosis of anaerobic digestion processes is a great challenge for anaerobic digestion reactors, which limits their stable operation. In this work, an online monitoring and alert system for upflow anaerobic sludge blanket (UASB) reactors is developed on the basis of a set of novel evaluating indexes. The two indexes, i.e., stability index S and auxiliary index a, which incorporate both gas- and liquid-phase parameters for UASB, enable a quantitative and comprehensive evaluation of reactor status. A series of shock tests is conducted to evaluate the response of the monitoring and alert system to organic overloading, hydraulic, temperature, and toxicant shocks. The results show that this system enables an accurate and rapid monitoring and diagnosis of the reactor status, and offers reliable early warnings on the potential risks. As the core of this system, the evaluating indexes are demonstrated to be of high accuracy and sensitivity in process evaluation and good adaptability to the artificial intelligence and automated control apparatus. This online monitoring and alert system presents a valuable effort to promote the automated monitoring and control of anaerobic digestion process, and holds a high promise for application.

Applicability of anaerobic membrane bioreactors for landfill leachate treatment: Review and opportunity

NASA Astrophysics Data System (ADS)

Abuabdou, Salahaldin M. A.; Bashir, Mohammed J. K.; Aun, Ng Choon; Sethupathi, Sumathi

2018-04-01

Sanitary landfilling is nowadays the most common way to eliminate municipal solid wastes (MSW). The resulted landfill leachate is a highly contaminated liquid. Even small quantities of this high-strength leachate can cause serious damage to surface and ground water receptors. Thus, these leachates must be appropriately treated before being discharged into the environment. In the last years, anaerobic membrane bioreactor (AnMBR) technology is being considered as a very attractive alternative for leachate treatment due to the significant advantages. In the last decade, many studies have been conducted in which various types of anaerobic reactors were used in combination with membranes. This paper is a review of the potential of anaerobic membrane bioreactor technology for municipal landfill leachate treatment. A critical review in AnMBR performance interesting landfill leachate in lab scale is also done. In addition, the review discusses the impact of the various factors on both biological and filtration performances of anaerobic membrane bioreactors.

BMP FILTERS: UPFLOW VS. DOWNFLOW

EPA Science Inventory

Stormwater filters are typically operated in a downflow mode. This research had two objectives: 1) to determine the increased life of a filter operated in an upflow mode, and 2) to determine if the operation of a downflow, mixed-media filter could be modeled using the power equat...

Lab-Scale Stimulation Results on Surrogate Fused Silica Samples

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

Carlos Fernandez

Lab-scale stimulation work on non-porous fused silica (similar mechanical properties to igneous rock) was performed using pure water, pure CO2 and water/CO2 mixtures to compare back to back fracturing performance of these fluids with PNNL's StimuFrac.

Latitude Dependence of Low-Altitude O+ Ion Upflow: Statistical Results From FAST Observations

NASA Astrophysics Data System (ADS)

Zhao, K.; Chen, K. W.; Jiang, Y.; Chen, W. J.; Huang, L. F.; Fu, S.

2017-09-01

We introduce a statistical model to explain the latitudinal dependence of the occurrence rate and energy flux of the ionospheric escaping ions, taking advantage of advances in the spatial coverage and accuracy of FAST observations. We use a weighted piecewise Gaussian function to fit the dependence, because two probability peaks are located in the dayside polar cusp source region and the nightside auroral oval zone source region. The statistical results show that (1) the Gaussian Mixture Model suitably describes the dayside polar cusp upflows, and the dayside and the nightside auroral oval zone upflows. (2) The magnetic latitudes of the ionospheric upflow source regions expand toward the magnetic equator as Kp increases, from 81° magnetic latitude (MLAT) (cusp upflows) and 63° MLAT (auroral oval upflows) during quiet times to 76° MLAT and 61° MLAT, respectively. (3) The dayside polar cusp region provides only 3-5% O+ upflows among all the source regions, which include the dayside auroral oval zone, dayside polar cusp, nightside auroral oval zone, and even the polar cap. However, observations show that more than 70% of upflows occur in the auroral oval zone and that the occurrence probability increases at the altitudes of 3500-4200 km, which is considered to be the lower altitude boundary of ion beams. This observed result suggests that soft electron precipitation and transverse wave heating are the most efficient ion energization/acceleration mechanisms at the altitudes of FAST orbit, and that the parallel acceleration caused by field-aligned potential drops becomes effective above that altitude.

My Lifelong Passion for Biochemistry and Anaerobic Microorganisms.

PubMed

Thauer, Rudolf Kurt

2015-01-01

Early parental influence led me first to medical school, but after developing a passion for biochemistry and sensing the need for a deeper foundation, I changed to chemistry. During breaks between semesters, I worked in various biochemistry labs to acquire a feeling for the different areas of investigation. The scientific puzzle that fascinated me most was the metabolism of the anaerobic bacterium Clostridium kluyveri, which I took on in 1965 in Karl Decker's lab in Freiburg, Germany. I quickly realized that little was known about the biochemistry of strict anaerobes such as clostridia, methanogens, acetogens, and sulfate-reducing bacteria and that these were ideal model organisms to study fundamental questions of energy conservation, CO2 fixation, and the evolution of metabolic pathways. My passion for anaerobes was born then and is unabated even after 50 years of study.

Metabolic engineering of strains: from industrial-scale to lab-scale chemical production.

PubMed

Sun, Jie; Alper, Hal S

2015-03-01

A plethora of successful metabolic engineering case studies have been published over the past several decades. Here, we highlight a collection of microbially produced chemicals using a historical framework, starting with titers ranging from industrial scale (more than 50 g/L), to medium-scale (5-50 g/L), and lab-scale (0-5 g/L). Although engineered Escherichia coli and Saccharomyces cerevisiae emerge as prominent hosts in the literature as a result of well-developed genetic engineering tools, several novel native-producing strains are gaining attention. This review catalogs the current progress of metabolic engineering towards production of compounds such as acids, alcohols, amino acids, natural organic compounds, and others.

Effect of limited aeration on the anaerobic treatment of evaporator condensate from a sulfite pulp mill.

PubMed

Zhou, Weili; Imai, Tsuyoshi; Ukita, Masao; Li, Fusheng; Yuasa, Akira

2007-01-01

Serious inhibition was found in the regular up-flow anaerobic sludge blanket (UASB) reactor in treating the evaporator condensate from a sulfite pulp mill, which contained high strength sulfur compounds. After applying the direct limited aeration in the UASB, the inhibition was alleviated gradually and the activity of the microorganisms was recovered. The COD removal rate increased from 40% to 80% at the organic loading rate of 8kgCODm(-3)d(-1) and a hydraulic retention time of 12h. Limited aeration caused no oxygen inhibition to the anaerobic microorganisms but instigated sulfide oxidization and H(2)S removal, which was beneficial to the methanogens. The experiment confirmed the feasibility of applying limited aeration in the anaerobic reactor to alleviate the sulfide inhibition. It also proved that the anaerobic system was actually aerotolerant. SEM observation showed that the predominant microorganisms partly changed from rod-shaped methanogens to cocci after the UASB reactor was aerated.

[A novel quantitative approach to study dynamic anaerobic process at micro scale].

PubMed

Zhang, Zhong-Liang; Wu, Jing; Jiang, Jian-Kai; Jiang, Jie; Li, Huai-Zhi

2012-11-01

Anaerobic digestion is attracting more and more interests because of its advantages such as low cost and recovery of clean energy etc. In order to overcome the drawbacks of the existed methods to study the dynamic anaerobic process, a novel microscopical quantitative approach at the granule level was developed combining both the microdevice and the quantitative image analysis techniques. This experiment displayed the process and characteristics of the gas production at static state for the first time and the results indicated that the method was of satisfactory repeatability. The gas production process at static state could be divided into three stages including rapid linear increasing stage, decelerated increasing stage and slow linear increasing stage. The rapid linear increasing stage was long and the biogas rate was high under high initial organic loading rate. The results showed that it was feasible to make the anaerobic process to be carried out in the microdevice; furthermore this novel method was reliable and could clearly display the dynamic process of the anaerobic reaction at the micro scale. The results are helpful to understand the anaerobic process.

Bioelectrochemical enhancement of anaerobic methanogenesis for high organic load rate wastewater treatment in a up-flow anaerobic sludge blanket (UASB) reactor.

PubMed

Zhao, Zhiqiang; Zhang, Yaobin; Chen, Shuo; Quan, Xie; Yu, Qilin

2014-10-17

A coupling process of anaerobic methanogenesis and electromethanogenesis was proposed to treat high organic load rate (OLR) wastewater. During the start-up stage, acetate removal efficiency of the electric-biological reactor (R1) reached the maximization about 19 percentage points higher than that of the control anaerobic reactor without electrodes (R2), and CH4 production rate of R1 also increased about 24.9% at the same time, while additional electric input was 1/1.17 of the extra obtained energy from methane. Coulombic efficiency and current recorded showed that anodic oxidation contributed a dominant part in degrading acetate when the metabolism of methanogens was low during the start-up stage. Along with prolonging operating time, aceticlastic methanogenesis gradually replaced anodic oxidation to become the main pathway of degrading acetate. When the methanogens were inhibited under the acidic conditions, anodic oxidation began to become the main pathway of acetate decomposition again, which ensured the reactor to maintain a stable performance. FISH analysis confirmed that the electric field imposed could enrich the H2/H(+)-utilizing methanogens around the cathode to help for reducing the acidity. This study demonstrated that an anaerobic digester with a pair of electrodes inserted to form a coupling system could enhance methanogenesis and reduce adverse impacts.

Anaerobic biodegradability of Category 2 animal by-products: methane potential and inoculum source.

PubMed

Pozdniakova, Tatiana A; Costa, José C; Santos, Ricardo J; Alves, M M; Boaventura, Rui A R

2012-11-01

Category 2 animal by-products that need to be sterilized with steam pressure according Regulation (EC) 1774/2002 are studied. In this work, 2 sets of experiments were performed in mesophilic conditions: (i) biomethane potential determination testing 0.5%, 2.0% and 5.0% total solids (TS), using sludge from the anaerobic digester of a wastewater treatment plant as inoculum; (ii) biodegradability tests at a constant TS concentration of 2.0% and different inoculum sources (digested sludge from a wastewater treatment plant; granular sludge from an upflow anaerobic sludge blanket reactor; leachate from a municipal solid waste landfill; and sludge from the slaughterhouse wastewater treatment anaerobic lagoon) to select the more adapted inoculum to the substrate in study. The higher specific methane production was of 317 mL CH(4)g(-1) VS(substrate) for 2.0% TS. The digested sludge from the wastewater treatment plant led to the lowest lag-phase period and higher methane potential rate. Copyright © 2012 Elsevier Ltd. All rights reserved.

Evaluation and characterization during the anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor.

PubMed

Xiao, Xiaolan; Huang, Zhenxing; Ruan, Wenquan; Yan, Lintao; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing

2015-10-01

The anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor (AnMBR) was investigated at two different operational modes, including no sludge discharge and daily sludge discharge of 20 L. The AnMBR provided excellent and reliable permeate quality with high COD removal efficiencies over 99%. The obvious accumulations of long chain fatty acids (LCFAs) and Ca(2+) were found in the anaerobic digester by precipitation and agglomeration. Though the physicochemical process contributed to attenuating the free LCFAs toxicity on anaerobic digestion, the digestion efficiency was partly influenced for the low bioavailability of those precipitates. Moreover, higher organic loading rate (OLR) of 5.8 kg COD/(m(3) d) and digestion efficiency of 78% were achieved as the AnMBR was stably operated with sludge discharge, where the membrane fouling propensity was also alleviated, indicating the crucial significance of SRT control on the treatment of high-strength kitchen waste slurry via AnMBRs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Anaerobic biodegradation of cyanide under methanogenic conditions.

PubMed Central

Fallon, R D; Cooper, D A; Speece, R; Henson, M

1991-01-01

Upflow, anaerobic, fixed-bed, activated charcoal biotreatment columns capable of operating at free cyanide concentrations of greater than 100 mg liter-1 with a hydraulic retention time of less than 48 h were developed. Methanogenesis was maintained under a variety of feed medium conditions which included ethanol, phenol, or methanol as the primary reduced carbon source. Under optimal conditions, greater than 70% of the inflow free cyanide was removed in the first 30% of the column height. Strongly complexed cyanides were resistant to removal. Ammonia was the nitrogen end product of cyanide transformation. In cell material removed from the charcoal columns, [14C]bicarbonate was the major carbon end product of [14C]cyanide transformation. PMID:1872600

Comparison between lab- and full-scale applications of in situ aeration of an old landfill and assessment of long-term emission development after completion.

PubMed

Hrad, Marlies; Gamperling, Oliver; Huber-Humer, Marion

2013-10-01

Sustainable landfilling has become a fundamental objective in many modern waste management concepts. In this context, the in situ aeration of landfills has been recognised for its potential to convert conventional anaerobic landfills into biological stabilised state, whereby both current and potential (long-term) emissions of the landfilled waste are mitigated. In recent years, different in situ aeration concepts have been successfully applied in Europe, North America and Asia, all pursuing different objectives and strategies. In Austria, the first full-scale application of in situ landfill aeration by means of low pressure air injection and simultaneous off-gas collection and treatment was implemented on an old, small municipal solid waste (MSW) landfill (2.6ha) in autumn 2007. Complementary laboratory investigations were conducted with waste samples taken from the landfill site in order to provide more information on the transferability of the results from lab- to full-scale aeration measures. In addition, long-term emission development of the stabilised waste after aeration completion was assessed in an ongoing laboratory experiment. Although the initial waste material was described as mostly stable in terms of the biological parameters gas generation potential over 21days (GP21) and respiration activity over 4days (RA4), the lab-scale experiments indicated that aeration, which led to a significant improvement of leachate quality, was accompanied by further measurable changes in the solid waste material under optimised conditions. Even 75weeks after aeration completion the leachate, as well as gaseous emissions from the stabilised waste material, remained low and stayed below the authorised Austrian discharge limits. However, the application of in situ aeration at the investigated landfill is a factor 10 behind the lab-based predictions after 3years of operation, mainly due to technical limitations in the full-scale operation (e.g. high air flow resistivity due

Survival of Alternaria alternata during anaerobic digestion of biomass in stirred tank reactors.

PubMed

Schleusner, Y; Bandte, M; Gossmann, M; Heiermann, M; Plöchl, M; Büttner, C

2012-01-01

The survival of Alternaria alternate during anaerobic digestion was investigated in context of a joint research project. The aim of this project was to estimate the phytosanitary risk of dissemination of pathogens by returning treated biomass as organic fertilizer to arable land. The studies were carried out in lab-scale stirred tank reactors under mesophilic conditions. After insertion of infected plant material into the reactors the influence on the viability of the fungal pathogen was studied concerning exposure time, pretreatment and storage of the digestates for four weeks or six months. The results clearly showed that anaerobic digestion leads to a complete inactivation of A. alternate already after an exposure time of six hours.

A super high-rate sulfidogenic system for saline sewage treatment.

PubMed

Tsui, To-Hung; Chen, Lin; Hao, Tianwei; Chen, Guang-Hao

2016-11-01

This study proposes a novel approach to resolve the challenging issue of sludge bed clogging in a granular sulfate-reducing upflow sludge bed (GSRUSB) reactor by means of introducing intermittent gas sparging to advance it into a super high-rate anaerobic bioreactor. Over a 196-day lab-scale trial, the GSRUSB system was operated from nominal hydraulic retention time of 4-hr to 40-min and achieved the highest organic loading rate of 13.31 kg COD/m 3 ·day which is substantially greater than the typical loading of 2.0-3.5 kg COD/m 3 ·day in a conventional upflow anaerobic sludge bed reactor treating dilute organic strength wastewater. The average organic removal efficiency and total dissolved sulfide of this system were 90 ± 4.2% and 158 ± 28 mg S/L, while organics residual in the effluent was 34 ± 14 mg COD/L. The control stage (without gas sparging) revealed that the sludge bed clogging happened concomitantly with the significant drop in extracellular polymeric substance content of granular sludge, through relevant chemical measurements and confocal laser scanning microscopy analyses. On the other hand, compared with increasing the effluent recirculation ratio (from 1.4 to 5), the three-dimensional computational fluid dynamics modeling in combination with energy dissipation analysis demonstrated that the gas sparging (at a superficial gas velocity of 0.8 m s -1 ) can create a 23 times higher liquid shear as well as enhanced particle attrition. Overall, this study not only developed a super high-rate anaerobic bioreactor for saline sewage treatment, but also shed light on the role of intermittent gas sparging in control of sludge bed clogging for anaerobic bioreactors. Copyright © 2016 Elsevier Ltd. All rights reserved.

Complete genome sequence of Peptoniphilus sp. strain ING2-D1G isolated from a mesophilic lab-scale completely stirred tank reactor utilizing maize silage in co-digestion with pig and cattle manure for biomethanation.

PubMed

Tomazetto, Geizecler; Hahnke, Sarah; Maus, Irena; Wibberg, Daniel; Pühler, Alfred; Schlüter, Andreas; Klocke, Michael

2014-12-20

The bacterium Peptoniphilus sp. strain ING2-D1G (DSM 28672), a mesophilic and obligate anaerobic bacterium belonging to the order Clostridiales was isolated from a biogas-producing lab-scale completely stirred tank reactor (CSTR) optimized for anaerobic digestion of maize silage in co-fermentation with pig and cattle manure. In this study, the whole genome sequence of Peptoniphilus sp. strain ING2-D1G, a new isolate potentially involved in protein breakdown and acidogenesis during biomass degradation, is reported. The chromosome of this strain is 1.6Mb in size and encodes genes predicted to be involved in the production of acetate, lactate and butyrate specifying the acidogenic metabolism of the isolate. Copyright © 2014 Elsevier B.V. All rights reserved.

Anaerobic biodegradation of aircraft deicing fluid in UASB reactors.

PubMed

Tham, P T Pham thi; Kennedy, K J Kevin J

2004-05-01

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions (0.8% 1.6% ADF (6000-12,000mg/L COD), 12-56h HRT, and 18-36gVSS/L) were conducted in continuous mode. The development of four empirical models describing process responses (i.e. COD removal efficiency, biomass-specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time, and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass-specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass-specific acetoclastic activity was improved two-fold from 0.23gCOD/gVSS/d for inoculum to a maximum of 0.55gCOD/gVSS/d during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. The predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate is increased. ADF toxicity effects were evident for 1.6% ADF at medium organic loadings (SOLR above 0.5gCOD/gVSS/d). In contrast, good reactor stability and excellent COD removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73gCOD/gVSS/d).

A new neural observer for an anaerobic bioreactor.

PubMed

Belmonte-Izquierdo, R; Carlos-Hernandez, S; Sanchez, E N

2010-02-01

In this paper, a recurrent high order neural observer (RHONO) for anaerobic processes is proposed. The main objective is to estimate variables of methanogenesis: biomass, substrate and inorganic carbon in a completely stirred tank reactor (CSTR). The recurrent high order neural network (RHONN) structure is based on the hyperbolic tangent as activation function. The learning algorithm is based on an extended Kalman filter (EKF). The applicability of the proposed scheme is illustrated via simulation. A validation using real data from a lab scale process is included. Thus, this observer can be successfully implemented for control purposes.

Treatment of ferrous-NTA-based NO x scrubber solution by an up-flow anaerobic packed bed bioreactor.

PubMed

Chandrashekhar, B; Sahu, Nidhi; Tabassum, Heena; Pai, Padmaraj; Morone, Amruta; Pandey, R A

2015-06-01

A bench scale system consisting of an up-flow packed bed bioreactor (UAPBR) made of polyurethane foam was used for the treatment and regeneration of aqueous solution of ferrous-NTA scrubbed with nitric oxide (NO). The biomass in the UAPBR was sequentially acclimatized under denitrifying and iron reducing conditions using ethanol as electron donor, after which nitric oxide (NO) gas was loaded continuously to the system by absorption. The system was investigated for different parameters viz. pH, removal efficiency of nitric oxide, biological reduction efficiency of Fe(II)NTA-NO and COD utilization. The Fe(II)NTA-NO reduction efficiency reached 87.8 % at a loading rate of 0.24 mmol L(-1) h(-1), while the scrubber efficiency reached more than 75 % with 250 ppm NO. Stover-Kincannon and a Plug-flow kinetic model based on Michaelis-Menten equation were used to describe the UAPBR performance with respect to Fe(II)NTA-NO and COD removal. The Stover-Kincannon model was found capable of describing the Fe(II)NTA-NO reduction (R m = 8.92 mM h(-1) and K NO = 11.46 mM h(-1)) while plug-flow model provided better fit to the COD utilization (U m = 66.62 mg L(-1) h(-1), K COD = 7.28 mg L(-1)). Analyses for pH, Fe(III)NTA, ammonium, nitrite concentration, and FTIR analysis of the medium samples indicated degradation of NTA, which leads to ammonium and nitrite accumulation in the medium, and affect the regeneration process.

Performance evaluation of a pilot-scale anaerobic membrane bioreactor (AnMBR) treating ethanol thin stillage.

PubMed

Dereli, R K; Urban, D R; Heffernan, B; Jordan, J A; Ewing, J; Rosenberger, G T; Dunaev, T I

2012-01-01

The ethanol industry has grown rapidly during the past ten years, mainly due to increasing oil prices. However, efficient and cost-effective solutions for treating thin stillage wastewater have still to be developed. The anaerobic membrane bioreactor (AnMBR) technology combines classical anaerobic treatment in a completely-stirred tank reactor (CSTR) with membrane separation. The combination of these two technologies can achieve a superior effluent quality and also increase biogas production compared to conventional anaerobic solutions. A pilot-scale AnMBR treating thin stillage achieved very high treatment efficiencies in terms of chemical oxygen demand (COD) and total suspended solids (TSS) removal (>98%). An average permeate flux of 4.3 L/m2 x h was achieved at relatively low transmembrane pressure (TMP) values (0.1-0.2 bars) with flat-sheet membranes. Experience gained during the pilot-scale studies provides valuable information for scaling up of AnMBRs treating complex and high-strength wastewaters.

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

PubMed

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

2013-10-01

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

Allometric Scaling of Wingate Anaerobic Power Test Scores in Women

ERIC Educational Resources Information Center

Hetzler, Ronald K.; Stickley, Christopher D.; Kimura, Iris F.

2011-01-01

In this study, we developed allometric exponents for scaling Wingate anaerobic test (WAnT) power data that are reflective in controlling for body mass (BM) and lean body mass (LBM) and established a normative WAnT data set for college-age women. One hundred women completed a standard WAnT. Allometric exponents and percentile ranks for peak (PP)…

Mesophilic biomethanation and treatment of poultry waste-water using pilot scale UASB reactor.

PubMed

Atuanya, Ernest I; Aigbirior, Moses

2002-07-01

The feasibility of applying the up-flow anaerobic sludge blanket (UASB) treatment for poultry waste (faeces) water was examined. A continuous-flow UASB pilot scale reactor of 3.50 L capacity using mixed culture was operated for 95 days to assess the treatability of poultry waste-water and its methane production. The maximum chemical oxygen demand (COD) removed was found to be 78% when organic loading rate (OLR) was 2.9 kg COD m(-3) day(-1) at hydraulic retention times (HRT) of 13.2 hr. The average biogas recovery was 0.26 m3 CH4 kg COD with an average methane content of 57% at mean temperature of 30 degrees C. Data indicate more rapid methanogenesis with higher loading rates and shorter hydraulic retention times. At feed concentration of 4.8 kg COD m(-3) day(-1), anaerobic digestion was severely retarded at all hydraulic retention time tested. This complication in the reactor operations may be linked to build-up of colloidal solids often associated with poultry waste water and ammonia toxicity. Isolates from granular sludge and effluent were found to be facultative anaerobes most of which were Pseudomonas genera.

Occurrence of ion upflow associated with ion/electron heating in the polar cap and cusp regions

NASA Astrophysics Data System (ADS)

Ji, E. Y.; Jee, G.; Kwak, Y. S.

2017-12-01

We investigate the occurrence frequency of ion upflow in association with ion/electron heating in the polar cap and cusp regions, using the data obtained from the European Incoherent Scatter Svalbard radar (ESR) during the period of 2000 to 2010. We classify the upflow events by four cases: driven by ion heating (case 1), electron heating (case 2), both ion and electron heatings (case 3), and without any heating (case 4). The statistical analysis of the data shows that the upflow normaly starts at around 350 km altitude and the occurrence seems to peak at 11 MLT. Among the four cases, the occurrence frequency of the upflow is maximized for the case 3 and then followed by case 2, case 1 and case 3, which indicates that both ion and electron heatings are associated with ion upflow. At around 500 km altitude, however, the occurrence frequency is maximized when there is no heating (case 4). We also investigate the dependence of the occurrence frequency of the upflow on Kp and F10.7 indices. The maximum occurrence frequency seems to occur at moderate geomagnetic condition (2 ≤ Kp < 5). As for the solar activity, the occurrence frequency is higher for low solar activity than for high solar activity. The results of this study suggest that the ion upflow occurring in the polar cap/cusp region is mostly driven by both ion and electron heatings.

End-effects-regime in full scale and lab scale rocket nozzles

NASA Astrophysics Data System (ADS)

Rojo, Raymundo; Tinney, Charles; Baars, Woutijn; Ruf, Joseph

2014-11-01

Modern rockets utilize a thrust-optimized parabolic-contour design for their nozzles for its high performance and reliability. However, the evolving internal flow structures within these high area ratio rocket nozzles during start up generate a powerful amount of vibro-acoustic loads that act on the launch vehicle. Modern rockets must be designed to accommodate for these heavy loads or else risk a catastrophic failure. This study quantifies a particular moment referred to as the ``end-effects regime,'' or the largest source of vibro-acoustic loading during start-up [Nave & Coffey, AIAA Paper 1973-1284]. Measurements from full scale ignitions are compared with aerodynamically scaled representations in a fully anechoic chamber. Laboratory scale data is then matched with both static and dynamic wall pressure measurements to capture the associating shock structures within the nozzle. The event generated during the ``end-effects regime'' was successfully reproduced in the both the lab-scale models, and was characterized in terms of its mean, variance and skewness, as well as the spectral properties of the signal obtained by way of time-frequency analyses.

Reproducibility of up-flow column percolation tests for contaminated soils

PubMed Central

Naka, Angelica; Sakanakura, Hirofumi; Kurosawa, Akihiko; Inui, Toru; Takeo, Miyuki; Inoba, Seiji; Watanabe, Yasutaka; Fujikawa, Takuro; Miura, Toshihiko; Miyaguchi, Shinji; Nakajou, Kunihide; Sumikura, Mitsuhiro; Ito, Kenichi; Tamoto, Shuichi; Tatsuhara, Takeshi; Chida, Tomoyuki; Hirata, Kei; Ohori, Ken; Someya, Masayuki; Katoh, Masahiko; Umino, Madoka; Negishi, Masanori; Ito, Keijiro; Kojima, Junichi; Ogawa, Shohei

2017-01-01

Up-flow column percolation tests are used at laboratory scale to assess the leaching behavior of hazardous substance from contaminated soils in a specific condition as a function of time. Monitoring the quality of these test results inter or within laboratory is crucial, especially if used for Environment-related legal policy or for routine testing purposes. We tested three different sandy loam type soils (Soils I, II and III) to determine the reproducibility (variability inter laboratory) of test results and to evaluate the difference in the test results within laboratory. Up-flow column percolation tests were performed following the procedure described in the ISO/TS 21268–3. This procedure consists of percolating solution (calcium chloride 1 mM) from bottom to top at a flow rate of 12 mL/h through softly compacted soil contained in a column of 5 cm diameter and 30 ± 5 cm height. Eluate samples were collected at liquid-to-solid ratio of 0.1, 0.2, 0.5, 1, 2, 5 and 10 L/kg and analyzed for quantification of the target elements (Cu, As, Se, Cl, Ca, F, Mg, DOC and B in this research). For Soil I, 17 institutions in Japan joined this validation test. The up-flow column experiments were conducted in duplicate, after 48 h of equilibration time and at a flow rate of 12 mL/h. Column percolation test results from Soils II and III were used to evaluate the difference in test results from the experiments conducted in duplicate in a single laboratory, after 16 h of equilibration time and at a flow rate of 36 mL/h. Overall results showed good reproducibility (expressed in terms of the coefficient of variation, CV, calculated by dividing the standard deviation by the mean), as the CV was lower than 30% in more than 90% of the test results associated with Soil I. Moreover, low variability (expressed in terms of difference between the two test results divided by the mean) was observed in the test results related to Soils II and III, with a variability lower than 30% in more

Effect of organic matter strength on anammox for modified greenhouse turtle breeding wastewater treatment.

PubMed

Chen, Chongjun; Huang, Xiaoxiao; Lei, Chenxiao; Zhang, Tian C; Wu, Weixiang

2013-11-01

Anaerobic ammonium-N removal from modified greenhouse turtle breeding wastewater with different chemical oxygen demand (COD) strengths (194.0-577.8 mg L(-1)) at relatively fixed C/N ratios (≈ 2) was investigated using a lab-scale up-flow anaerobic sludge blanket (UASB) anammox reactor. During the entire experiment, the total nitrogen (TN) removal efficiency was about 85% or higher, while the average COD removal efficiency was around 56.5 ± 7.9%. Based on the nitrogen and carbon balance, the nitrogen removal contribution was 79.6 ± 4.2% for anammox, 12.7 ± 3.0% for denitrification+denitritation and 7.7 ± 4.9% for other mechanisms. Denaturing gradient gel electrophoresis (DGGE) analyses revealed that Planctomycete, Proteobacteria and Chloroflexi bacteria were coexisted in the reactor. Anammox was always dominant when the reactor was fed with different COD concentrations, which indicated the stability of the anammox process with the coexistence of the denitrification process in treating greenhouse turtle breeding wastewater. Copyright © 2013 Elsevier Ltd. All rights reserved.

Suitability assessment of grey water quality treated with an upflow-downflow siliceous sand/marble waste filtration system for agricultural and industrial purposes.

PubMed

Chaabane, Safa; Riahi, Khalifa; Hamrouni, Hédi; Thayer, Béchir Ben

2017-04-01

The present study examines the suitability assessment of an upflow-downflow siliceous sand/marble waste filtration system for treatment and reuse of grey water collected from bathrooms of the student residential complex at the Higher Institute of Engineering Medjez El Bab (Tunisia). Once the optimization of grey water pre-treatment system has been determined, the filtration system was operated at different hydraulic loading rate and media filter proportions in order to assess the suitability of treated grey water for irrigational purpose according to salinity hazard, sodium hazard, magnesium hazard, permeability index, water infiltration rate, and widely used graphical methods. Suitability of the treated grey water for industrial purpose was evaluated in terms of foaming, corrosion, and scaling. Under optimal operational conditions, results reveals that treated grey water samples with an upflow-downflow siliceous sand/marble waste filtration system may be considered as a good and an excellent water quality suitable for irrigation purpose. However, treated grey water was found not appropriate for industrial purpose due to high concentrations of calcium and sodium that can generate foaming and scaling harm to boilers. These results suggest that treated grey water with an upflow-downflow siliceous sand/marble waste filtration system would support production when used as irrigation water.

Influence of thermal hydrolysis pretreatment on organic transformation characteristics of high solid anaerobic digestion.

PubMed

Han, Yun; Zhuo, Yang; Peng, Dangcong; Yao, Qian; Li, Huijuan; Qu, Qiliang

2017-11-01

The study evaluated the influence of thermal hydrolysis pretreatment (THP) on anaerobic digestion (AD) ability of high solid sludge. The transformation characteristics of organics during the THP+AD process of dewatering sludge from wastewater treatment plant was investigated using a lab-scale THP reactor and four anaerobic digesters. The reduction efficiency of volatile suspended solids using THP+AD exceeded 49%. The acceleration of biogas production during AD was due to the enhancement of protein hydrolysis and acidogenesis by THP. THP had only minimal influence on the improvement of carbohydrate acidogenesis. The hydrolysis of poly phosphates was likely the main reaction of phosphorus transformation. Biochemical generation of sulfide and ammonia nitrogen occurred during the acidogenesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

NMR and MALDI-TOF MS based characterization of exopolysaccharides in anaerobic microbial aggregates from full-scale reactors

PubMed Central

Gonzalez-Gil, Graciela; Thomas, Ludivine; Emwas, Abdul-Hamid; Lens, Piet N. L.; Saikaly, Pascal E.

2015-01-01

Anaerobic granular sludge is composed of multispecies microbial aggregates embedded in a matrix of extracellular polymeric substances (EPS). Here we characterized the chemical fingerprint of the polysaccharide fraction of EPS in anaerobic granules obtained from full-scale reactors treating different types of wastewater. Nuclear magnetic resonance (NMR) signals of the polysaccharide region from the granules were very complex, likely as a result of the diverse microbial population in the granules. Using nonmetric multidimensional scaling (NMDS), the 1H NMR signals of reference polysaccharides (gellan, xanthan, alginate) and those of the anaerobic granules revealed that there were similarities between the polysaccharides extracted from granules and the reference polysaccharide alginate. Further analysis of the exopolysaccharides from anaerobic granules, and reference polysaccharides using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that exopolysaccharides from two of the anaerobic granular sludges studied exhibited spectra similar to that of alginate. The presence of sequences related to the synthesis of alginate was confirmed in the metagenomes of the granules. Collectively these results suggest that alginate-like exopolysaccharides are constituents of the EPS matrix in anaerobic granular sludge treating different industrial wastewater. This finding expands the engineered environments where alginate has been found as EPS constituent of microbial aggregates. PMID:26391984

NMR and MALDI-TOF MS based characterization of exopolysaccharides in anaerobic microbial aggregates from full-scale reactors.

PubMed

Gonzalez-Gil, Graciela; Thomas, Ludivine; Emwas, Abdul-Hamid; Lens, Piet N L; Saikaly, Pascal E

2015-09-22

Anaerobic granular sludge is composed of multispecies microbial aggregates embedded in a matrix of extracellular polymeric substances (EPS). Here we characterized the chemical fingerprint of the polysaccharide fraction of EPS in anaerobic granules obtained from full-scale reactors treating different types of wastewater. Nuclear magnetic resonance (NMR) signals of the polysaccharide region from the granules were very complex, likely as a result of the diverse microbial population in the granules. Using nonmetric multidimensional scaling (NMDS), the (1)H NMR signals of reference polysaccharides (gellan, xanthan, alginate) and those of the anaerobic granules revealed that there were similarities between the polysaccharides extracted from granules and the reference polysaccharide alginate. Further analysis of the exopolysaccharides from anaerobic granules, and reference polysaccharides using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) revealed that exopolysaccharides from two of the anaerobic granular sludges studied exhibited spectra similar to that of alginate. The presence of sequences related to the synthesis of alginate was confirmed in the metagenomes of the granules. Collectively these results suggest that alginate-like exopolysaccharides are constituents of the EPS matrix in anaerobic granular sludge treating different industrial wastewater. This finding expands the engineered environments where alginate has been found as EPS constituent of microbial aggregates.

Significance of dissolved methane in effluents of anaerobically ...

EPA Pesticide Factsheets

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10–30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11–100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Micro

A modified two-point titration method for the determination of volatile fatty acids in anaerobic systems.

PubMed

Mu, Zhe-Xuan; He, Chuan-Shu; Jiang, Jian-Kai; Zhang, Jie; Yang, Hou-Yun; Mu, Yang

2018-08-01

The volatile fatty acids (VFA) concentration plays important roles in the rapid start-up and stable operation of anaerobic reactors. It's essential to develop a simple and accurate method to monitor the VFA concentration in the anaerobic systems. In present work, a modified two-point titration method was developed to determine the VFA concentration. The results show that VFA concentration in standard solutions estimated by the titration method coincided well with that measured by gas chromatograph, where all relative errors were lower than 5.5%. Compared with the phosphate, ammonium and sulfide subsystems, the effect of bicarbonate on the accuracy of the developed method was relatively significant. When the bicarbonate concentration varied from 0 to 8 mmol/L, the relative errors increased from 1.2% to 30% for VFA concentration at 1 mmol/L, but were within 2.0% for that at 5 mmol/L. In addition, the VFA composition affected the accuracy of the titration method to some extent. This developed titration method was further proved to be effective with practical effluents from a lab-scale anaerobic reactor under organic shock loadings and an unstable full-scale anaerobic reactor. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of pentachlorophenol and chemical oxygen demand mass concentrations in influent on operational behaviors of upflow anaerobic sludge blanket (UASB) reactor.

PubMed

Shen, Dong-Sheng; He, Ruo; Liu, Xin-Wen; Long, Yan

2006-08-25

Upflow anaerobic sludge blanket (UASB) reactor that was seeded with anaerobic sludge acclimated to chlorophenols was used to investigate the feasibility of anaerobic biotreatment of synthetic wastewater containing pentachlorophenol (PCP) with additional sucrose as carbon source. Two sets of UASB reactors were operated at one time. But the seeded sludge for the two reactors was different and Reactor I was seeded with the sludge that was acclimated to PCP completely for half a year, and Reactor II was seeded with the mixed sludge that was acclimated for half a year to PCP, 4-CP, 3-CP or 2-CP, respectively. The degradation of PCP and the operation fee treating the wastewater are affected by the concentration of MEDS (microorganism easily degradable substrate). So the confirmation of the suitable ratio of [COD] and [PCP] was the key factor of treating the wastewater containing PCP economically and efficiently. During the experiment, the synthetic wastewater with 180.0 mg L(-1) PCP and 1250-10000 mg L(-1) COD could be treated steadily in the experimental Reactor I. The removal efficiency of PCP was more than 99.5% and the removal efficiency of COD was up to 90%. [PCP] (concentration of PCP) in effluent was less than 0.5 mg L(-1). [PCP] in influent could affect proper [COD] (concentration of COD) range in influent that was required for maintenance of steady running of the experimental reactor with a hydraulic retention time (HRT) from 20 to 22 h. [PCP] in influent would directly affect the necessary [COD] in influent when the UASB reactor ran normally and treated the wastewater containing PCP. When [PCP] was 100.4, 151.6 and 180.8 mg L(-1) in influent, respectively, [COD] in influent had to be controlled about 1250-7500, 2500-5000 and 5000 mg L(-1) to maintain the UASB reactor steady running normally and contemporarily ensure that [COD] and [PCP] in effluent were less than 300 and 0.5 mg L(-1), respectively. With the increase of [PCP] in influent, the range of variation

Performance assessment of two-stage anaerobic digestion of kitchen wastes.

PubMed

Bo, Zhang; Pin-Jing, He

2014-01-01

This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

Effect of ultrasonication on anaerobic degradability of solid waste digestate.

PubMed

Boni, M R; D'Amato, E; Polettini, A; Pomi, R; Rossi, A

2016-02-01

This paper evaluates the effect of ultrasonication on anaerobic biodegradability of lignocellulosic residues. While ultrasonication has been commonly applied as a pre-treatment of the feed substrate, in the present study a non-conventional process configuration based on recirculation of sonicated digestate to the biological reactor was evaluated at the lab-scale. Sonication tests were carried out at different applied energies ranging between 500 and 50,000kJ/kg TS. Batch anaerobic digestion tests were performed on samples prepared by mixing sonicated and untreated substrate at two different ratios (25:75 and 75:25 w/w). The results showed that when applied as a post-treatment of digestate, ultrasonication can positively affect the yield of anaerobic digestion, mainly due to the dissolution effect of complex organic molecules that have not been hydrolyzed by biological degradation. A good correlation was found between the CH4 production yield and the amount of soluble organic matter at the start of digestion tests. The maximum gain in biogas production was 30% compared to that attained with the unsonicated substrate, which was tentatively related to the type and concentration of the metabolic products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of high gas production during thermophilic anaerobic digestion in pilot-scale and lab-scale reactors on survival of the thermotolerant pathogens Clostridium perfringens and Campylobacter jejuni in piggery wastewater.

PubMed

Skillman, L C; Bajsa, O; Ho, L; Santhanam, B; Kumar, M; Ho, G

2009-07-01

Safe reuse of animal wastes to capture energy and nutrients, through anaerobic digestion processes, is becoming an increasingly desirable solution to environmental pollution. Pathogen decay is the most important safety consideration and is in general, improved at elevated temperatures and longer hydraulic residence times. During routine sampling to assess pathogen decay in thermophilic digestion, an inversely proportional relationship between levels of Clostridium perfringens and gas production was observed. Further samples were collected from pilot-scale, bench-scale thermophilic reactors and batch scale vials to assess whether gas production (predominantly methane) could be a useful indicator of decay of the thermotolerant pathogens C. perfringens and Campylobacter jejuni. Pathogen levels did appear to be lower where gas production and levels of methanogens were higher. This was evident at each operating temperature (50, 57, 65 degrees C) in the pilot-scale thermophilic digesters, although higher temperatures also reduced the numbers of pathogens detected. When methane production was higher, either when feed rate was increased, or pH was lowered from 8.2 (piggery wastewater) to 6.5, lower numbers of pathogens were detected. Although a number of related factors are known to influence the amount and rate of methane production, it may be a useful indicator of the removal of the pathogens C. perfringens and C. jejuni.

Anaerobic treatment of antibiotic production wastewater pretreated with enhanced hydrolysis: Simultaneous reduction of COD and ARGs.

PubMed

Yi, Qizhen; Zhang, Yu; Gao, Yingxin; Tian, Zhe; Yang, Min

2017-03-01

The presence of high concentration antibiotics in wastewater can disturb the stability of biological wastewater treatment systems and promote generation of antibiotic resistance genes (ARGs) during the treatment. To solve this problem, a pilot system consisting of enhanced hydrolysis pretreatment and an up-flow anaerobic sludge bed (UASB) reactor in succession was constructed for treating oxytetracycline production wastewater, and the performance was evaluated in a pharmaceutical factory in comparison with a full-scale anaerobic system operated in parallel. After enhanced hydrolysis under conditions of pH 7 and 85 °C for 6 h, oxytetracycline production wastewater with an influent chemical oxygen demand (COD) of 11,086 ± 602 mg L -1 was directly introduced into the pilot UASB reactor. With the effective removal of oxytetracycline and its antibacterial potency (from 874 mg L -1 to less than 0.61 mg L -1 and from 900 mg L -1 to less than 0.84 mg L -1 , respectively) by the enhanced hydrolysis pretreatment, an average COD removal rate of 83.2%, 78.5% and 68.9% was achieved at an organic loading rate of 3.3, 4.8 and 5.9 kg COD m -3  d -1 , respectively. At the same time, the relative abundances of the total tetracycline (tet) genes and a mobile element (Class 1 integron (intI1)) in anaerobic sludge on day 96 were one order of magnitude lower than those in inoculated sludge on day 0 (P < 0.01). The reduction of ARGs was further demonstrated by metagenomic sequencing. By comparison, the full-scale anaerobic system treating oxytetracycline production wastewater with an influent COD of 3720 ± 128 mg L -1 after dilution exhibited a COD removal of 51 ± 4% at an organic loading rate (OLR) 1.2 ± 0.2 kg m -3  d -1 , and a total tet gene abundance in sludge was five times higher than the pilot-scale system (P < 0.01). The above result demonstrated that enhanced hydrolysis as a pretreatment method could enable efficient anaerobic treatment of

Studies on the toxic effects of pentachlorophenol on the biological activity of anaerobic granular sludge.

PubMed

Liu, Xin-Wen; He, Ruo; Shen, Dong-Sheng

2008-09-01

In order to explore the pathway of the anaerobic biotreatment of the wastewater containing pentachlorophenol (PCP) and ensure the normal operation of Upflow Anaerobic Sludge Blanket (UASB) reactor, the anaerobic sludge under different acclimation conditions were selected to seed and start up UASB reactors. Anaerobic toxicity assays were employed to study the biological activity, the tolerance and the capacity to degrade PCP of different anaerobic granular sludge from UASB reactors. Results showed that the anaerobic granular sludge acclimated to chlorophenols (CPs) could degrade PCP more quickly (up to 9.50mg-PCP g(-1)TVS d(-1)). And the anaerobic granular sludge without acclimation to CPs had only a little activity of degrading PCP (less than 0.07 mg-PCP g(-1)TVS d(-1)). Different PCP concentrations (2, 4, 6, 8 mg L(-1)) had different inhibition effects on glucose utilization, volatile fatted acidity (VFA)-degrading and methanogens activity of PCP degradation anaerobic granular sludge, and the biological activity declined with the increase in PCP concentration. The methanogens activity suffered inhibition from PCP more easily. The different acclimation patterns of seeded sludge had distinctly different effects on biological activity of the degradation of PCP of anaerobic granular sludge from UASB reactors. The biological activity of the anaerobic granular sludge acclimated to PCP only was also inhibited. This inhibition was weak compared to that of anaerobic granular sludge acclimated to CPs, further, the activity could recover more quickly in this case. In the same reactor, the anaerobic granular sludge from the mid and base layers showed higher tolerance to PCP than that from super layer or if the sludge is unacclimated to CPs, and the corresponding recovery time of the biological activity in the mid and base layers were short. Acetate-utilizing methanogens and syntrophic propinate degraders were sensitive to PCP, compared to syntrophic butyrate degraders.

Kinetic modeling of the effect of solids retention time on methanethiol dynamics in anaerobic digestion.

PubMed

Zhang, Dian; Strawn, Mary; Novak, John T; Wang, Zhi-Wu

2018-07-01

The highly volatile methanethiol (MT) with an extremely low odor threshold and distinctive putrid smell is often identified as a major odorous compound generated under anaerobic conditions. As an intermediate compound in the course of anaerobic digestion, the extent of MT emission is closely related to the time of anaerobic reaction. In this study, lab-scale anaerobic digesters were operated at solids retention time (SRTs) of 15, 20, 25, 30, 40 and 50 days to investigate the effect of SRT on MT emission. The experimental results demonstrated a bell-shaped curve of MT emission versus SRT with a peak around 20 days SRT. In order to understand this SRT effect, a kinetic model was developed to describe MT production and utilization dynamics in the course of anaerobic digestion and calibrated with the experimental results collected from this study. The model outcome revealed that the high protein content in the feed sludge together with the large maintenance coefficient of MT fermenters are responsible for the peak MT emission emergence in the range of typical SRT used for anaerobic digestion. A further analysis of the kinetic model shows that it can be extensively simplified with reasonable approximation to a form that anaerobic digestion practitioners could easily use to predict the MT and SRT relationship. Copyright © 2018 Elsevier Ltd. All rights reserved.

Anaerobic/aerobic treatment of greywater via UASB and MBR for unrestricted reuse.

PubMed

Abdel-Shafy, Hussein I; Al-Sulaiman, Ahmed Makki; Mansour, Mona S M

2015-01-01

The aim of the present study was to investigate the efficiency of integrated up-flow anaerobic sludge blanket (UASB) as anaerobic system followed by membrane bioreactor (MBR) as aerobic system for the treatment of greywater for unrestricted reuse. Pilot-scale UASB and MBR units were installed and operated in the NRC, Egypt. Real raw greywater was subjected to UASB and the effluent was further treated with microfiltration MBR. The necessary trans-membrane pressure difference is applied by the water head above the membrane (gravity flow) without any energy input. The average characteristics of the raw greywater were 95, 392, 298, 10.45, 0.4, 118.5 and 28 mg/L for total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphates, nitrates, oil and grease, and total Kjeldahl nitrogen (TKN), respectively. The pH was 6.71. The UASB treatment efficiency reached 19.3, 57.8, 67.5 and 83.7% for TSS, COD, BOD5 and oil and grease, respectively. When the UASB effluent was further treated with MBR, the overall removal rate achieved 97.7, 97.8, 97.4 and 95.8% for the same parameters successively. The characteristics of the final effluent reached 2.5, 8.5, 6.1, 0.95, 4.6 and 2.3 mg/L for TSS, COD, BOD, phosphates, oil and grease and TKN, respectively. This final treated effluent could cope with the unrestricted water reuse of local Egyptian guidelines.

Application of Methanobrevibacter acididurans in anaerobic digestion.

PubMed

Savant, D V; Ranade, D R

2004-01-01

To operate anaerobic digesters successfully under acidic conditions, hydrogen utilizing methanogens which can grow efficiently at low pH and tolerate high volatile fatty acids (VFA) are desirable. An acid tolerant hydrogenotrophic methanogen viz. Methanobrevibacter acididurans isolated from slurry of an anaerobic digester running on alcohol distillery wastewater has been described earlier by this lab. This organism could grow optimally at pH 6.0. In the experiments reported herein, M. acididurans showed better methanogenesis under acidic conditions with high VFA, particularly acetate, than Methanobacterium bryantii, a common hydrogenotrophic inhabitant of anaerobic digesters. Addition of M. acididurans culture to digesting slurry of acidogenic as well as methanogenic digesters running on distillery wastewater showed increase in methane production and decrease in accumulation of volatile fatty acids. The results proved the feasibility of application of M. acididurans in anaerobic digesters.

Removal of tetracyclines, sulfonamides, and quinolones by industrial-scale composting and anaerobic digestion processes.

PubMed

Liu, Hang; Pu, Chengjun; Yu, Xiaolu; Sun, Ying; Chen, Junhao

2018-02-15

This study evaluated and compared the removal of antibiotics by industrial-scale composting and anaerobic digestion at different seasons. Twenty compounds belonged to three classes of widely used veterinary antibiotics (i.e., tetracyclines, sulfonamides, and quinolones) were investigated. Results show that of the three groups of antibiotics, tetracyclines were dominant in swine feces and poorly removed by anaerobic digestion with significant accumulation in biosolids, particularly in winter. Compared to that in winter, a much more effective removal (> 97%) by anaerobic digestion was observed for sulfonamides in summer. By contrast, quinolones were the least abundant antibiotics in swine feces and exhibited a higher removal by anaerobic digestion in winter than in summer. The overall removal of antibiotics by aerobic composting could be more than 90% in either winter or summer. Nevertheless, compost products from livestock farms in Beijing contained much higher antibiotics than commercial organic fertilizers. Thus, industrial composting standards should be strictly applied to livestock farms to further remove antibiotics and produce high quality organic fertilizer.

Evaluation of decentralized treatment of sewage employing Upflow Septic Tank/Baffled Reactor (USBR) in developing countries.

PubMed

Sabry, Tarek

2010-02-15

A new concept for a low-cost modified septic tank, named Upflow Septic Tank/Baffled Reactor (USBR), was constructed and tested in a small village in Egypt. During almost one year of continuous operation and monitoring, this system was found to have very satisfactory removal results, where the average results of COD, BOD, and TSS removal efficiencies were 84%, 81%, and 89%, respectively, and the results of the experiment proved that the second compartment (Anaerobic Baffled Reactor) was the main treatment unit in removing the pollutants during the start-up period and at the very early steady-state stage. However, after this period and during the steady-state operation conditions, the second compartment served as a polishing step. Also, it was observed that the USBR system was not affected by the imposed shock loads at the peak flow and organic periods. The results showed that the system is slightly influenced by the drop in the temperature. Decreasing in BOD and COD removal by factor of 9% was observed, when temperature decreases from the average of 35 degrees C in summer time (for the first 127 days) to the average of 22 degrees C in winter time (between day 252 and day 280). Whereas, the TSS removals were not affected by the drop in temperature. The results of the sewage flow variations during one year of operation were compared with Goodrich Formula to see the applicability of this equation in rural developing countries. MAIN FINDING OF THE WORK: The Upflow Septic Tank/Baffled Reactor system could become a promising alternative to the conventional treatment plants in rural developing countries.

Accelerated anaerobic hydrolysis rates under a combination of intermittent aeration and anaerobic conditions.

PubMed

Jensen, T R; Lastra Milone, T; Petersen, G; Andersen, H R

2017-04-01

Anaerobic hydrolysis in activated return sludge was investigated in laboratory scale experiments to find if intermittent aeration would accelerate anaerobic hydrolysis rates compared to anaerobic hydrolysis rates under strict anaerobic conditions. The intermittent reactors were set up in a 240 h experiment with intermittent aeration (3 h:3 h) in a period of 24 h followed by a subsequent anaerobic period of 24 h in a cycle of 48 h which was repeated five times during the experiment. The anaerobic reactors were kept under strict anaerobic conditions in the same period (240 h). Two methods for calculating hydrolysis rates based on soluble chemical oxygen demand were compared. Two-way analysis of variance with the Bonferroni post-test was performed in order to register any significant difference between reactors with intermittent aeration and strictly anaerobic conditions respectively. The experiment demonstrated a statistically significant difference in favor of the reactors with intermittent aeration showing a tendency towards accelerated anaerobic hydrolysis rates due to application of intermittent aeration. The conclusion of the work is thus that intermittent aeration applied in the activated return sludge process can improve the treatment capacity further in full scale applications.

Lab and Pore-Scale Study of Low Permeable Soils Diffusional Tortuosity

NASA Astrophysics Data System (ADS)

Lekhov, V.; Pozdniakov, S. P.; Denisova, L.

2016-12-01

Diffusion plays important role in contaminant spreading in low permeable units. The effective diffusion coefficient of saturated porous medium depends on this coefficient in water, porosity and structural parameter of porous space - tortuosity. Theoretical models of relationship between porosity and diffusional tortuosity are usually derived for conceptual granular models of medium filled by solid particles of simple geometry. These models usually do not represent soils with complex microstructure. The empirical models, like as Archie's law, based on the experimental electrical conductivity data are mostly useful for practical applications. Such models contain empirical parameters that should be defined experimentally for given soil type. In this work, we compared tortuosity values obtained in lab-scale diffusional experiments and pore scale diffusion simulation for the studied soil microstructure and exanimated relationship between tortuosity and porosity. Samples for the study were taken from borehole cores of low-permeable silt-clay formation. Using the samples of 50 cm3 we performed lab scale diffusional experiments and estimated the lab-scale tortuosity. Next using these samples we studied the microstructure with X-ray microtomograph. Shooting performed on undisturbed microsamples of size 1,53 mm with a resolution ×300 (10243 vox). After binarization of each obtained 3-D structure, its spatial correlation analysis was performed. This analysis showed that the spatial correlation scale of the indicator variogram is considerably smaller than microsample length. Then there was the numerical simulation of the Laplace equation with binary coefficients for each microsamples. The total number of simulations at the finite-difference grid of 1753 cells was 3500. As a result the effective diffusion coefficient, tortuosity and porosity values were obtained for all studied microsamples. The results were analyzed in the form of graph of tortuosity versus porosity. The 6

Microbial monitoring of ammonia removal in a UASB reactor treating pre-digested chicken manure with anaerobic granular inoculum.

PubMed

Yangin-Gomec, Cigdem; Pekyavas, Goksen; Sapmaz, Tugba; Aydin, Sevcan; Ince, Bahar; Akyol, Çağrı; Ince, Orhan

2017-10-01

Performance and microbial community dynamics in an upflow anaerobic sludge bed (UASB) reactor coupled with anaerobic ammonium oxidizing (Anammox) treating diluted chicken manure digestate (Total ammonia nitrogen; TAN=123±10mg/L) were investigated for a 120-d operating period in the presence of anaerobic granular inoculum. Maximum TAN removal efficiency reached to above 80% with as low as 20mg/L TAN concentrations in the effluent. Moreover, total COD (tCOD) with 807±215mg/L in the influent was removed by 60-80%. High-throughput sequencing revealed that Proteobacteria, Actinobacteria, and Firmicutes were dominant phyla followed by Euryarchaeota and Bacteroidetes. The relative abundance of Planctomycetes significantly increased from 4% to 8-9% during the late days of the operation with decreased tCOD concentration, which indicated a more optimum condition to favor ammonia removal through anammox route. There was also significant association between the hzsA gene and ammonia removal in the UASB reactor. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fast Startup of Semi-Pilot-Scale Anaerobic Digestion of Food Waste Acid Hydrolysate for Biogas Production.

PubMed

Huang, Chao; Zhao, Cheng; Guo, Hai-Jun; Wang, Can; Luo, Mu-Tan; Xiong, Lian; Li, Hai-Long; Chen, Xue-Fang; Chen, Xin-De

2017-12-27

In this study, a fast startup of semi-pilot-scale anaerobic digestion of food waste acid hydrolysate for biogas production was carried out for the first time. During the period of fast startup, more than 85% of chemical oxygen demand (COD) can be degraded, and even more than 90% of COD can be degraded during the later stage of anaerobic digestion. During this anaerobic digestion process, the biogas yield, the methane yield, and the CH 4 content in biogas were 0.542 ± 0.056 m 3 /kg COD consumption , 0.442 ± 0.053 m 3 /kg COD consumption , and 81.52 ± 3.05%, respectively, and these values were high and stable. Besides, the fermentation pH was very stable, in which no acidification was observed during the anaerobic digestion process (outlet pH was 7.26 ± 0.05 for the whole anaerobic digestion). Overall, the startup of this anaerobic digestion can be completed in a short period (the system can be stable 2 days after the substrate was pumped into the bioreactor), and anaerobic digestion of food waste acid hydrolysate is feasible and attractive for industrial treatment of food waste and biogas production.

Anaerobic treatment of winery wastewater in fixed bed reactors.

PubMed

Ganesh, Rangaraj; Rajinikanth, Rajagopal; Thanikal, Joseph V; Ramanujam, Ramamoorty Alwar; Torrijos, Michel

2010-06-01

The treatment of winery wastewater in three upflow anaerobic fixed-bed reactors (S9, S30 and S40) with low density floating supports of varying size and specific surface area was investigated. A maximum OLR of 42 g/l day with 80 +/- 0.5% removal efficiency was attained in S9, which had supports with the highest specific surface area. It was found that the efficiency of the reactors increased with decrease in size and increase in specific surface area of the support media. Total biomass accumulation in the reactors was also found to vary as a function of specific surface area and size of the support medium. The Stover-Kincannon kinetic model predicted satisfactorily the performance of the reactors. The maximum removal rate constant (U(max)) was 161.3, 99.0 and 77.5 g/l day and the saturation value constant (K(B)) was 162.0, 99.5 and 78.0 g/l day for S9, S30 and S40, respectively. Due to their higher biomass retention potential, the supports used in this study offer great promise as media in anaerobic fixed bed reactors. Anaerobic fixed-bed reactors with these supports can be applied as high-rate systems for the treatment of large volumes of wastewaters typically containing readily biodegradable organics, such as the winery wastewater.

Redundancy in Anaerobic Digestion Microbiomes during Disturbances by the Antibiotic Monensin

PubMed Central

Spirito, Catherine M.; Daly, Sarah E.; Werner, Jeffrey J.

2018-01-01

ABSTRACT The antibiotic monensin is fed to dairy cows to increase milk production efficiency. A fraction of this monensin is excreted into the cow manure. Previous studies have found that cow manure containing monensin can negatively impact the performance of anaerobic digesters, especially upon first introduction. Few studies have examined whether the anaerobic digester microbiome can adapt to monensin during the operating time. Here, we conducted a long-term time series study of four lab-scale anaerobic digesters fed with cow manure. We examined changes in both the microbiome composition and function of the anaerobic digesters when subjected to the dairy antibiotic monensin. In our digesters, monensin was not rapidly degraded under anaerobic conditions. The two anaerobic digesters that were subjected to manure from monensin feed-dosed cows exhibited relatively small changes in microbiome composition and function due to relatively low monensin concentrations. At higher concentrations of monensin, which we dosed directly to control manure (from dairy cows without monensin), we observed major changes in the microbiome composition and function of two anaerobic digesters. A rapid introduction of monensin to one of these anaerobic digesters led to the impairment of methane production. Conversely, more gradual additions of the same concentrations of monensin to the other anaerobic digester led to the adaptation of the anaerobic digester microbiomes to the relatively high monensin concentrations. A member of the candidate OP11 (Microgenomates) phylum arose in this anaerobic digester and appeared to be redundant with certain Bacteroidetes phylum members, which previously were dominating. IMPORTANCE Monensin is a common antibiotic given to dairy cows in the United States and is partly excreted with dairy manure. An improved understanding of how monensin affects the anaerobic digester microbiome composition and function is important to prevent process failure for farm

Influence of preservation temperature on the characteristics of anaerobic ammonium oxidation (anammox) granular sludge.

PubMed

Xing, Bao-Shan; Guo, Qiong; Jiang, Xiao-Yan; Chen, Qian-Qian; Li, Peng; Ni, Wei-Min; Jin, Ren-Cun

2016-05-01

Preserving active anaerobic ammonium oxidation (anammox) biomass is a potential method for securing sufficient seeding biomass for the rapid start-up of full-scale anammox processes. In this study, anammox granules were cultured in an upflow anaerobic sludge blanket (UASB) reactor (R0), and then the enriched anammox granules were preserved at 35, 20, 4, and -30 °C. The subsequent reactivation characteristics of the granules were evaluated in four UASB reactors (denoted R1, R2, R3, and R4, respectively) to investigate the effect of preservation temperature on the characteristics of anammox granules and their reactivation performance. The results demonstrated that 4 °C was the optimal preservation temperature for maintaining the biomass, activity, settleability, and integrity of the anammox granules and their cellular structures. During the preservation period, a first-order exponential decay model may be used to simulate the decay of anammox biomass and activity. The protein-to-polysaccharide ratio in the extracellular polymeric substances and the heme c content could not effectively indicate the changes in settleability and activity of the anammox granules, respectively, and a loss of bioactivity was positively associated with the degree of anaerobic ammonium-oxidizing bacteria cell lysis. After 42 days of storage, the anammox granules preserved at 4 °C (R3) exhibited a better recovery performance than those preserved at 20 °C (R2), -30 °C (R4), and 35 °C (R1). The comprehensive comparison indicated that 4 °C is the optimal storage temperature for anammox granular sludge because it promotes improved maintenance and recovery performance properties.

Impacts of auroral current systems on ionospheric upflow/outflow

NASA Astrophysics Data System (ADS)

Burleigh, M.; Zettergren, M. D.; Lynch, K. A.; Lessard, M.; Harrington, M.; Varney, R. H.; Reimer, A.

2017-12-01

The downward current region of an auroral current system often contains large perpendicular DC electric fields. These DC electric fields frictionally heat the local ion population resulting in anisotropic increases in ion temperature that cause large pressure gradients which push the ions outward and upward. These ions may undergo further acceleration from transverse heating by broadband ELF waves and at high altitudes the mirror force can propel ions to escape velocities, resulting in outflow to the magnetosphere. Despite these processes being generally well-known, ion outflow remains difficult to predict due to the myriad of processes acting over a large range of altitudes and physical regimes. The resulting temperature anisotropies, which are known to be able to affect upflow, have an unclear degree of impact in highly variable situations like substorm expansions on the nightside or PMAFs/FTEs on the dayside.In this study we use an anisotropic fluid model, GEMINI-TIA, to examine detailed features of temperature anisotropies and resulting ion downflows/upflows/outflows occurring during the ISINGLASS and RENU2 sounding rocket campaigns. GEMINI-TIA is a 2D ionospheric model is based on a truncated 16-moment description and solves the conservation of mass, momentum, parallel energy, and perpendicular energy for species relevant to the E, F, and topside ionospheric regions. This model encapsulates ionospheric upflow and outflow processes through the inclusion of DC electric fields, and empirical descriptions of heating by soft electron precipitation and BBELF waves. The fluid transport equations are accompanied by an electrostatic current continuity equation to self-consistently describe auroral electric fields. Data used to constrain the model can include perpendicular electric fields, characteristic energy, and total energy flux from incoherent scatter radar, any available neutral density and wind measurements, and precipitating electron fluxes. Results from these

Toxicity and biodegradability of selected N-substituted phenols under anaerobic conditions

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

Donlon, B.; Razo-Flores, E.; Hwu, C.S.

1995-12-31

The anaerobic toxicity and biodegradability of N-substituted aromatics were evaluated in order to obtain information on their ultimate biotreatment. The toxicity of selected N-substituted aromatic compounds toward acetoclastic methanogens in granular sludge was measured in batch assays. This toxicity was highly correlated with compound hydrophobicity, indicating that partitioning into the bacterial membranes was an important factor in the toxicity. However, other factors, such as chemical interactions with key cell components, were suggested to be playing an important role. Nitroaromatic compounds were, on the average, over 300-fold more toxic than their amino-substituted counterparts. This finding suggests that the facile reduction ofmore » nitro-groups known to occur in anaerobic environments would result in a high level of detoxification. To test this hypothesis, continuous lab-scale upward-flow anaerobic sludge bed reactors treating 2-nitrophenol and 4-nitrophenol were established. The 4-nitrophenol was readily converted to the corresponding 4-aminophenol, whereas complete mineralization of 2-nitrophenol via intermediate formation of 2-aminophenol was obtained. These conversions led to a dramatic detoxification of the nitrophenols, because it was feasible to treat the highly toxic nitrophenolics at high organic loading rates.« less

[Pilot-scale opposite folded plate hybrid anaerobic reactor (OFPHAR) in treatment of sewage].

PubMed

Han, Xiang-Kui; Ye, Chang-Bing; Zhuang, Jin-Peng; Bi, Dong; Wang, Lei

2008-11-01

Based on the theories of mass-transfer and two-double integrated staged multi-phase anaerobe (TSMPA), a pilot-scale opposite folded plate hybrid anaerobic reactor (OFPHAR) was designed to treat low concentration sewage. All the trial lasted 12 months and the results indicated that the optimal HRT was 6h. At this HRT, the COD, TP and TN removal rate were 78.58%, 35.15%, 39.17%, respectively, at 25 degrees C +/- 2 degrees C. The optimal rate of anaerobic section was 45%-65%. Controlled HRT = 6 h, the COD, TP and TN removal rate were 64.37%, 20.72%, 23.65%, respectively, and the specific methane production capacity were 1.85 mL/(g x h) when the temperature decreased to 7 degrees C. The results of trial indicated that apply this OFPHAR to treat low concentration sewage at low temperature in north China is feasible.

Evaluation of Integrated Anaerobic Digestion and Hydrothermal Carbonization for Bioenergy Production

PubMed Central

Reza, M. Toufiq; Werner, Maja; Pohl, Marcel; Mumme, Jan

2014-01-01

Lignocellulosic biomass is one of the most abundant yet underutilized renewable energy resources. Both anaerobic digestion (AD) and hydrothermal carbonization (HTC) are promising technologies for bioenergy production from biomass in terms of biogas and HTC biochar, respectively. In this study, the combination of AD and HTC is proposed to increase overall bioenergy production. Wheat straw was anaerobically digested in a novel upflow anaerobic solid state reactor (UASS) in both mesophilic (37 °C) and thermophilic (55 °C) conditions. Wet digested from thermophilic AD was hydrothermally carbonized at 230 °C for 6 hr for HTC biochar production. At thermophilic temperature, the UASS system yields an average of 165 LCH4/kgVS (VS: volatile solids) and 121 L CH4/kgVS at mesophilic AD over the continuous operation of 200 days. Meanwhile, 43.4 g of HTC biochar with 29.6 MJ/kgdry_biochar was obtained from HTC of 1 kg digestate (dry basis) from mesophilic AD. The combination of AD and HTC, in this particular set of experiment yield 13.2 MJ of energy per 1 kg of dry wheat straw, which is at least 20% higher than HTC alone and 60.2% higher than AD only. PMID:24962786

Slow swimming, fast strikes: effects of feeding behavior on scaling of anaerobic metabolism in epipelagic squid.

PubMed

Trueblood, Lloyd A; Seibel, Brad A

2014-08-01

Many pelagic fishes engage prey at high speeds supported by high metabolic rates and anaerobic metabolic capacity. Epipelagic squids are reported to have among the highest metabolic rates in the oceans as a result of demanding foraging strategies and the use of jet propulsion, which is inherently inefficient. This study examined enzymatic proxies of anaerobic metabolism in two species of pelagic squid, Dosidicus gigas and Doryteuthis pealeii (Lesueur 1821), over a size range of six orders of magnitude. We hypothesized that activity of the anaerobically poised enzymes would be high and increase with size as in ecologically similar fishes. In contrast, we demonstrate that anaerobic metabolic capacity in these organisms scales negatively with body mass. We explored several cephalopod-specific traits, such as the use of tentacles to capture prey, body morphology and reduced relative prey size of adult squids, that may create a diminished reliance on anaerobically fueled burst activity during prey capture in large animals. © 2014. Published by The Company of Biologists Ltd.

Upflow bioreactor with septum and pressure release mechanism

DOEpatents

Hansen, Conly L.; Hansen, Carl S.; Pack, Kevin; Milligan, John; Benefiel, Bradley C.; Tolman, C. Wayne; Tolman, Kenneth W.

2010-04-20

An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes means for releasing pressure buildup in the lower chamber. In one configuration, the septum includes a releasable portion having an open position and a closed position. The releasable portion is configured to move to the open position in response to pressure buildup in the lower chamber. In the open position fluid communication between the lower chamber and the upper chamber is increased. Alternatively the lower chamber can include a pressure release line that is selectively actuated by pressure buildup. The pressure release mechanism can prevent the bioreactor from plugging and/or prevent catastrophic damage to the bioreactor caused by high pressures.

Comparative performance evaluation of full-scale anaerobic and aerobic wastewater treatment processes in Brazil.

PubMed

von Sperling, M; Oliveira, S C

2009-01-01

This article evaluates and compares the actual behavior of 166 full-scale anaerobic and aerobic wastewater treatment plants in operation in Brazil, providing information on the performance of the processes in terms of the quality of the generated effluent and the removal efficiency achieved. The observed results of effluent concentrations and removal efficiencies of the constituents BOD, COD, TSS (total suspended solids), TN (total nitrogen), TP (total phosphorus) and FC (faecal or thermotolerant coliforms) have been compared with the typical expected performance reported in the literature. The treatment technologies selected for study were: (a) predominantly anaerobic: (i) septic tank + anaerobic filter (ST + AF), (ii) UASB reactor without post-treatment (UASB) and (iii) UASB reactor followed by several post-treatment processes (UASB + POST); (b) predominantly aerobic: (iv) facultative pond (FP), (v) anaerobic pond followed by facultative pond (AP + FP) and (vi) activated sludge (AS). The results, confirmed by statistical tests, showed that, in general, the best performance was achieved by AS, but closely followed by UASB reactor, when operating with any kind of post-treatment. The effluent quality of the anaerobic processes ST + AF and UASB reactor without post-treatment was very similar to the one presented by facultative pond, a simpler aerobic process, regarding organic matter.

RANS Simulation (Virtual Blade Model [VBM]) of Single Lab Scaled DOE RM1 MHK Turbine

DOE Data Explorer

Javaherchi, Teymour; Stelzenmuller, Nick; Aliseda, Alberto; Seydel, Joseph

2014-04-15

Attached are the .cas and .dat files for the Reynolds Averaged Navier-Stokes (RANS) simulation of a single lab-scaled DOE RM1 turbine implemented in ANSYS FLUENT CFD-package. The lab-scaled DOE RM1 is a re-design geometry, based of the full scale DOE RM1 design, producing same power output as the full scale model, while operating at matched Tip Speed Ratio values at reachable laboratory Reynolds number (see attached paper). In this case study the flow field around and in the wake of the lab-scaled DOE RM1 turbine is simulated using Blade Element Model (a.k.a Virtual Blade Model) by solving RANS equations coupled with k-\\omega turbulence closure model. It should be highlighted that in this simulation the actual geometry of the rotor blade is not modeled. The effect of turbine rotating blades are modeled using the Blade Element Theory. This simulation provides an accurate estimate for the performance of device and structure of it's turbulent far wake. Due to the simplifications implemented for modeling the rotating blades in this model, VBM is limited to capture details of the flow field in near wake region of the device. The required User Defined Functions (UDFs) and look-up table of lift and drag coefficients are included along with the .cas and .dat files.

Kinetics of thermophilic anaerobes in fixed-bed reactors.

PubMed

Perez, M; Romero, L I; Sales, D

2001-08-01

The main objective of this study is to estimate growth kinetic constants and the concentration of "active" attached biomass in two anaerobic thermophilic reactors which contain different initial sizes of immobilized anaerobic mixed cultures and decompose distillery wastewater. This paper studies the substrate decomposition in two lab-scale fixed-bed reactors operating at batch conditions with corrugated tubes as support media. It can be demonstrated that high micro-organisms-substrate ratios favor the degradation activity of the different anaerobic cultures, allowing the stable operation without lag-phases and giving better quality in effluent. The kinetic parameters obtained--maximum specific growth rates (mu(max)), non-biodegradable substrate (S(NB)) and "active or viable biomass" concentrations (X(V0))--were obtained by applying the Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz], with COD as substrate and methane (CH4) as the main product of the anaerobic process. This method is suitable to calculate and to differentiate the main kinetic parameters of both the total anaerobic mixed culture and the methanogenic population. Comparison of experimental measured concentration of volatile attached solids (VS(att)) in both reactors with the estimated "active" biomass concentrations obtained by applying Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz] shows that a large amount of inert matter is present in the fixed-bed reactor.

Releasing characteristics and fate of heavy metals from phytoremediation crop residues during anaerobic digestion.

PubMed

Lee, Jongkeun; Park, Ki Young; Cho, Jinwoo; Kim, Jae Young

2018-01-01

In this study, lab-scale batch tests were conducted to investigate releasing characteristics of heavy metals according to degradation of heavy metal containing biomass. The fate of heavy metals after released from biomass was also determined through adsorption tests and Visual MINTEQ simulation. According to the anaerobic batch test results as well as volatile solids and carbon balance analyses, maximum of 60% by wt. of biomass was degraded. During the anaerobic biodegradation, among Cd, Cu, Ni, Pb, and Zn, only Cu and Zn were observed in soluble form (approximately 40% by wt. of input mass). The discrepancy between degradation ratio of biomass and ratio of released heavy metals mass from biomass was observed. It seems that this discordance was caused by the fate (i.e., precipitated with sulfur/hydroxide or adsorbed onto sorbents) of each heavy metal types in solution after being released from biomass. Thus, releasing characteristics and fate of heavy metal should be considered carefully to predict stability of anaerobic digestion process for heavy metal-containing biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

Occurrence rate of ion upflow and downflow observed by the Poker Flat Incoherent Scatter Radar (PFISR)

NASA Astrophysics Data System (ADS)

Zou, S.; Lu, J.; Varney, R. H.

2017-12-01

This study aims to investigate the occurrence rate of ion upflow and downflow events in the auroral ionosphere, using a full 3-year (2011-2013) dataset collected by the Poker Flat Incoherent Scatter Radar (PFISR) at 65.5° magnetic latitude. Ion upflow and downflow events are defined if there are three consecutive data points larger/smaller than 100/-100 m/s in the ion field-aligned velocity altitude profile. Their occurrence rates have been evaluated as a function of magnetic local time (MLT), season, geomagnetic activity, solar wind and interplanetary magnetic field (IMF). We found that the ion upflows are twice more likely to occur on the nightside than the dayside, and have slightly higher occurrence rate near Fall equinox. In contrast, the ion downflow events are more likely to occur in the afternoon sector but also during Fall equinox. In addition, the occurrence rate of ion upflows on the nightside increases when the aurora electrojet index (AE) and planetary K index (Kp) increase, while the downflows measured on the dayside clearly increase as the AE and Kp increase. In general, the occurrence rate of ion upflows increases with enhanced solar wind and IMF drivers. This correlation is particularly strong between the upflows on the nightside and the solar wind dynamic pressure and IMF Bz. The lack of correlation of upflows on the dayside with these parameters is due to the location of PFISR, which is usually equatorward of the dayside auroral zone and within the nightside auroral zone under disturbed conditions. The occurrence rate of downflow at all MLTs does not show strong dependence on the solar wind and IMF conditions. However, it occurs much more frequently on the dayside when the IMF By is strongly positive, i.e., >10 nT and the IMF Bz is strongly negative, i.e., < -10 nT. We suggest that the increased occurrence rate of downflows on the dayside is associated with dayside storm-enhanced density and the plume.

Anaerobic sequencing batch reactor in pilot scale for treatment of tofu industry wastewater

NASA Astrophysics Data System (ADS)

Rahayu, Suparni Setyowati; Purwanto, Budiyono

2015-12-01

The small industry of tofu production process releases the waste water without being processed first, and the wastewater is directly discharged into water. In this study, Anaerobic Sequencing Batch Reactor in Pilot Scale for Treatment of Tofu Industry was developed through an anaerobic process to produce biogas as one kind of environmentally friendly renewable energy which can be developed into the countryside. The purpose of this study was to examine the fundamental characteristics of organic matter elimination of industrial wastewater with small tofu effective method and utilize anaerobic active sludge with Anaerobic Sequencing Bath Reactor (ASBR) to get rural biogas as an energy source. The first factor is the amount of the active sludge concentration which functions as the decomposers of organic matter and controlling selectivity allowance to degrade organic matter. The second factor is that HRT is the average period required substrate to react with the bacteria in the Anaerobic Sequencing Bath Reactor (ASBR).The results of processing the waste of tofu production industry using ASBR reactor with active sludge additions as starter generates cumulative volume of 5814.4 mL at HRT 5 days so that in this study it is obtained the conversion 0.16 L of CH4/g COD and produce biogas containing of CH4: 81.23% and CO2: 16.12%. The wastewater treatment of tofu production using ASBR reactor is able to produce renewable energy that has economic value as well as environmentally friendly by nature.

Why do lab-scale experiments ever resemble geological scale patterning?

NASA Astrophysics Data System (ADS)

Ferdowsi, Behrooz; Jones, Brandon C.; Stein, Jeremy L.; Shinbrot, Troy

2017-11-01

The Earth and other planets are abundant with curious and poorly understood surface patterns. Examples include sand dunes, periodic and aperiodic ridges and valleys, and networks of river and submarine channels. We make the minimalist proposition that the dominant mechanism governing these varied patterns is mass conservation: notwithstanding detailed particulars, the universal rule is mass conservation and there are only a finite number of surface patterns that can result from this process. To test this minimalist proposition, we perform experiments in a vertically vibrated bed of fine grains, and we show that every one of a wide variety of patterns seen in the laboratory is also seen in recorded geomorphologies. We explore a range of experimental driving frequencies and amplitudes, and we complement these experimental results with a non-local cellular automata model that reproduces the surface patterns seen using a minimalist approach that allows a free surface to deform subject to mass conservation and simple known forces such as gravity. These results suggest a common cause for the effectiveness of lab-scale models for geological scale patterning that otherwise ought to have no reasonable correspondence.

Characterization of an Autotrophic Nitrogen-Removing Biofilm from a Highly Loaded Lab-Scale Rotating Biological Contactor

PubMed Central

Pynaert, Kris; Smets, Barth F.; Wyffels, Stijn; Beheydt, Daan; Siciliano, Steven D.; Verstraete, Willy

2003-01-01

In this study, a lab-scale rotating biological contactor (RBC) treating a synthetic NH4+ wastewater devoid of organic carbon and showing high N losses was examined for several important physiological and microbial characteristics. The RBC biofilm removed 89% ± 5% of the influent N at the highest surface load of approximately 8.3 g of N m−2 day−1, with N2 as the main end product. In batch tests, the RBC biomass showed good aerobic and anoxic ammonium oxidation (147.8 ± 7.6 and 76.5 ± 6.4 mg of NH4+-N g of volatile suspended solids [VSS]−1 day−1, respectively) and almost no nitrite oxidation (< 1 mg of N g of VSS−1 day−1). The diversity of aerobic ammonia-oxidizing bacteria (AAOB) and planctomycetes in the biofilm was characterized by cloning and sequencing of PCR-amplified partial 16S rRNA genes. Phylogenetic analysis of the clones revealed that the AAOB community was fairly homogeneous and was dominated by Nitrosomonas-like species. Close relatives of the known anaerobic ammonia-oxidizing bacterium (AnAOB) Kuenenia stuttgartiensis dominated the planctomycete community and were most probably responsible for anoxic ammonium oxidation in the RBC. Use of a less specific planctomycete primer set, not amplifying the AnAOB, showed a high diversity among other planctomycetes, with representatives of all known groups present in the biofilm. The spatial organization of the biofilm was characterized using fluorescence in situ hybridization (FISH) with confocal scanning laser microscopy (CSLM). The latter showed that AAOB occurred side by side with putative AnAOB (cells hybridizing with probe PLA46 and AMX820/KST1275) throughout the biofilm, while other planctomycetes hybridizing with probe PLA886 (not detecting the known AnAOB) were present as very conspicuous spherical structures. This study reveals that long-term operation of a lab-scale RBC on a synthetic NH4+ wastewater devoid of organic carbon yields a stable biofilm in which two bacterial groups, thought

RANS Simulation (Rotating Reference Frame Model [RRF]) of Single Lab-Scaled DOE RM1 MHK Turbine

DOE Data Explorer

Javaherchi, Teymour; Stelzenmuller, Nick; Aliseda, Alberto; Seydel, Joseph

2014-04-15

Attached are the .cas and .dat files for the Reynolds Averaged Navier-Stokes (RANS) simulation of a single lab-scaled DOE RM1 turbine implemented in ANSYS FLUENT CFD-package. The lab-scaled DOE RM1 is a re-design geometry, based of the full scale DOE RM1 design, producing same power output as the full scale model, while operating at matched Tip Speed Ratio values at reachable laboratory Reynolds number (see attached paper). In this case study taking advantage of the symmetry of lab-scaled DOE RM1 geometry, only half of the geometry is models using (Single) Rotating Reference Frame model [RRF]. In this model RANS equations, coupled with k-\\omega turbulence closure model, are solved in the rotating reference frame. The actual geometry of the turbine blade is included and the turbulent boundary layer along the blade span is simulated using wall-function approach. The rotation of the blade is modeled by applying periodic boundary condition to sets of plane of symmetry. This case study simulates the performance and flow field in the near and far wake of the device at the desired operating conditions. The results of these simulations were validated against in-house experimental data. Please see the attached paper.

Inhibitory effect of high phenol concentration in treating coal gasification wastewater in anaerobic biofilter.

PubMed

Li, Yajie; Tabassum, Salma; Chu, Chunfeng; Zhang, Zhenjia

2018-02-01

In this paper, the inhibition of methanogens by phenol in coal gasification wastewater (CGW) was investigated by both anaerobic toxicity tests and a lab-scale anaerobic biofilter reactor (AF). The anaerobic toxicity tests indicated that keeping the phenol concentration in the influent under 280mg/L could maintain the methanogenic activity. In the AF treating CGW, the result showed that adding glucose solution as co-substrate could be beneficial for the quick start-up of the reactor. The effluent chemical oxygen demand (COD) and total phenol reached 1200 and 100mg/L, respectively, and the methane production rate was 175mLCH 4 /gCOD/day. However, if the concentration of phenol was increased, the inhibition of anaerobic micro-organisms was irreversible. The threshold of total phenol for AF operation was 200-250mg/L. The extracellular polymeric substances (EPS) and particle size distribution of anaerobic granular sludge in the different stages were also examined, and the results indicated that the influence of toxicity in the system was more serious than its effect on flocculation of EPS. Moreover, the proportion of small size anaerobic granular sludge gradually increased from 10.2% to 34.6%. The results of high through-put sequencing indicated that the abundance of the Chloroflexi and Planctomycetes was inhibited by the toxicity of the CGW, and some shifts in the microbial community were observed at different stages. Copyright © 2017. Published by Elsevier B.V.

Assessing the changes in E. coli levels and nutrient dynamics during vermicomposting of food waste under lab and field scale conditions.

PubMed

Cao, Wenlong; Vaddella, Venkata; Biswas, Sagor; Perkins, Katherine; Clay, Cameron; Wu, Tong; Zheng, Yawen; Ndegwa, Pius; Pandey, Pramod

2016-11-01

Vermicomposting (VC) has proven to be a promising method for treating garden, household, and municipal wastes. Although the VC has been used extensively for converting wastes into fertilizers, pathogens such as Escherichia coli (E. coli) survival during this process is not well documented. In this study, both lab and field scale experiments were conducted assessing the impacts of earthworms in reducing E. coli concentration during VC of food waste. In addition, other pertinent parameters such as temperature, carbon and nitrogen content, moisture content, pH, volatile solids, micronutrients (P, K, Ca, Mg, and S), and heavy metals (Zn, Mn, Fe, and Cu) were monitored during the study. The lab and field scale experiments were conducted for 107 and 103 days, respectively. The carbon to nitrogen ratio (C/N) decreased by 54 % in the lab scale study and by 36 % in the field study. Results showed that VC was not significantly effective in reducing E. coli levels in food waste under both lab and field scale settings. The carbon to nitrogen ratio (C/N) decreased by 54 % in the lab scale study and by 36 % in the field study.

Thermospheric neutral density estimates from heater-induced ion up-flow at EISCAT

NASA Astrophysics Data System (ADS)

Kosch, Michael; Ogawa, Yasunobu; Yamazaki, Yosuke; Vickers, Hannah; Blagoveshchenskaya, Nataly

We exploit a recently-developed technique to estimate the upper thermospheric neutral density using measurements of ionospheric plasma parameters made by the EISCAT UHF radar during ionospheric modification experiments. Heating the electrons changes the balance between upward plasma pressure gradient and downward gravity, resulting in ion up-flow up to ~200 m/s. This field-aligned flow is retarded by collisions, which is directly related to the neutral density. Whilst the ion up-flow is consistent with the plasma pressure gradient, the estimated thermospheric neutral density depends on the assumed composition, which varies with altitude. Results in the topside ionosphere are presented.

Application of lab derived kinetic biodegradation parameters at the field scale

NASA Astrophysics Data System (ADS)

Schirmer, M.; Barker, J. F.; Butler, B. J.; Frind, E. O.

2003-04-01

Estimating the intrinsic remediation potential of an aquifer typically requires the accurate assessment of the biodegradation kinetics, the level of available electron acceptors and the flow field. Zero- and first-order degradation rates derived at the laboratory scale generally overpredict the rate of biodegradation when applied to the field scale, because limited electron acceptor availability and microbial growth are typically not considered. On the other hand, field estimated zero- and first-order rates are often not suitable to forecast plume development because they may be an oversimplification of the processes at the field scale and ignore several key processes, phenomena and characteristics of the aquifer. This study uses the numerical model BIO3D to link the laboratory and field scale by applying laboratory derived Monod kinetic degradation parameters to simulate a dissolved gasoline field experiment at Canadian Forces Base (CFB) Borden. All additional input parameters were derived from laboratory and field measurements or taken from the literature. The simulated results match the experimental results reasonably well without having to calibrate the model. An extensive sensitivity analysis was performed to estimate the influence of the most uncertain input parameters and to define the key controlling factors at the field scale. It is shown that the most uncertain input parameters have only a minor influence on the simulation results. Furthermore it is shown that the flow field, the amount of electron acceptor (oxygen) available and the Monod kinetic parameters have a significant influence on the simulated results. Under the field conditions modelled and the assumptions made for the simulations, it can be concluded that laboratory derived Monod kinetic parameters can adequately describe field scale degradation processes, if all controlling factors are incorporated in the field scale modelling that are not necessarily observed at the lab scale. In this way

Nitrification denitrification enhanced biological phosphorous removal (NDEBPR) occurs in a lab-scale alternating hypoxic/oxic membrane bioreactor.

PubMed

Sibag, Mark; Kim, Han-Seung

2012-01-01

Strict anaerobic or anoxic maintenance of the system and process susceptibility to low organic loading are major concerns in nitrification denitrification enhanced biological phosphorous removal (NDEBPR). The study has initiated NDEBPR in a lab-scale alternating hypoxic/oxic membrane bioreactor by developing an enhanced mixed microbial culture capable of removing 97±2% COD, 99±0.84% NH(3)-N, 90±3% TN, and 96±1% TP-PO(4)(3-) with 20-day SRT. The viable cells ranging from 1.6×10(8) to 2.0×10(8)cells/ml estimated from the total bacterial genomic DNA (6.43-7.83 μg DNA/ml) represented only 5% of the MLVSS indicating low microbial biomass concentration. Reducing the organic load from 1250 to 750 mg COD/ml as glucose did not deteriorate the effluent quality (3.77±1.0 mg N-TN/l; 0.08±0.24 mg NH(3)-N/l; and 0.32±0.10 mg PO(4)(3-)-P/l). These observations are characteristics of activated sludge that harbors denitrifying polyphosphate accumulating organisms (DPAOs). The results showed that NDEBPR can be achieved under alternating hypoxic/oxic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of chlortetracycline amended feed on anaerobic sequencing batch reactor performance of swine manure digestion.

PubMed

Dreher, Teal M; Mott, Henry V; Lupo, Christopher D; Oswald, Aaron S; Clay, Sharon A; Stone, James J

2012-12-01

The effects of antimicrobial chlortetracycline (CTC) on the anaerobic digestion (AD) of swine manure slurry using anaerobic sequencing batch reactors (ASBRs) was investigated. Reactors were loaded with manure collected from pigs receiving CTC and no-antimicrobial amended diets at 2.5 g/L/d. The slurry was intermittently fed to four 9.5L lab-scale anaerobic sequencing batch reactors, two with no-antimicrobial manure, and two with CTC-amended manure, and four 28 day ASBR cycles were completed. The CTC concentration within the manure was 2 8 mg/L immediately after collection and 1.02 mg/L after dilution and 250 days of storage. CTC did not inhibit ASBR biogas production extent, however the volumetric composition of methane was significantly less (approximately 13% and 15% for cycles 1 and 2, respectively) than the no-antimicrobial through 56 d. CTC decreased soluble chemical oxygen demand and acetic acid utilization through 56 d, after which acclimation to CTC was apparent for the duration of the experiment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Field Performance of a Newly Developed Upflow Filtration Device

EPA Science Inventory

The objective of this research is to examine the removal capacities of a newly developed Upflow filtration device for treatment of stormwater. The device was developed by engineers at the University of Alabama through a Small Business Innovative Research (SBIR) grant from the U....

Evaluation the anaerobic hydrolysis acidification stage of kitchen waste by pH regulation.

PubMed

Wang, Yaya; Zang, Bing; Li, Guoxue; Liu, Yu

2016-07-01

This study analyzed the composition and characteristic of kitchen waste (KW) from closed cleaning station of Chaoyang District, Beijing. It was featured by high vegetables and peels contents. This study investigated effect of pH regulation and uncontrolled pH (CK) on the lab-scale anaerobic hydrolysis acidification stage of KW. The optimal adjusting mode by NaOH (including dosage and frequency) was evaluated according to indexes of pH, VFAs, NH4(+)-N, TS, VS, TS/VS, TS and VS removal rate. The treatment 4 as first two days adjusting per 16h and then one time per day at pH 7 was chosen as the optimal mode with high VFAs content(47.31g/L), TS and VS removal rate (42.95% and 54.01%, respectively), low adjusting frequency, fewer dosage and practical operability. Thus, adjusting mode of treatment 4 could be considered using in anaerobic hydrolysis acidification stage on engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of the inter-tablet coating uniformity for an active coating process at lab and pilot scale.

PubMed

Just, Sarah; Toschkoff, Gregor; Funke, Adrian; Djuric, Dejan; Scharrer, Georg; Khinast, Johannes; Knop, Klaus; Kleinebudde, Peter

2013-11-30

The objective of this study was to enhance the inter-tablet coating uniformity in an active coating process at lab and pilot scale by statistical design of experiments. The API candesartan cilexetil was applied onto gastrointestinal therapeutic systems containing the API nifedipine to obtain fixed dose combinations of these two drugs with different release profiles. At lab scale, the parameters pan load, pan speed, spray rate and number of spray nozzles were examined. At pilot scale, the parameters pan load, pan speed, spray rate, spray time, and spray pressure were investigated. A low spray rate and a high pan speed improved the coating uniformity at both scales. The number of spray nozzles was identified as the most influential variable at lab scale. With four spray nozzles, the highest CV value was equal to 6.4%, compared to 13.4% obtained with two spray nozzles. The lowest CV of 4.5% obtained with two spray nozzles was further reduced to 2.3% when using four spray nozzles. At pilot scale, CV values between 2.7% and 11.1% were achieved. Since the test of uniformity of dosage units accepts CV values of up to 6.25%, this active coating process is well suited to comply with the pharmacopoeial requirements. Copyright © 2013 Elsevier B.V. All rights reserved.

Performance of a lab-scale bio-electrochemical assisted septic tank for the anaerobic treatment of black water.

PubMed

Zamalloa, Carlos; Arends, Jan B A; Boon, Nico; Verstraete, Willy

2013-06-25

Septic tanks are used for the removal of organic particulates in wastewaters by physical accumulation instead of through the biological production of biogas. Improved biogas production in septic tanks is crucial to increase the potential of this system for both energy generation and organic matter removal. In this study, the effect on the biogas production and biogas quality of coupling a 20 L lab-scale septic tank with a microbial electrolysis cell (MEC) was investigated and compared with a standard septic tank. Both reactors were operated at a volumetric organic loading rate of 0.5gCOD/Ld and a hydraulic retention time between 20 and 40 days using black water as an input under mesophilic conditions for a period of 3 months. The MEC-septic tank was operated at an applied voltage of 2.0±0.1V and the current experienced ranged from 40 mA (0.9A/m(2) projected electrode area) to 180 mA (5A/m(2) projected electrode area). The COD removal was of the order of 85% and the concentration of residual COD was not different between both reactors. Yet, the total phosphorous in the output was on average 39% lower in the MEC-septic tank. Moreover, the biogas production rate in the MEC-septic tank was a factor of 5 higher than in the control reactor and the H2S concentration in the biogas was a factor of 2.5 lower. The extra electricity supplied to the MEC-septic tank was recovered as extra biogas produced. Overall, it appears that the combination of MEC and a septic tank offers perspectives in terms of lower discharge of phosphorus and H2S, nutrient recuperation and a more reliable supply of biogas. Copyright © 2013 Elsevier B.V. All rights reserved.

Steady performance of a zero valent iron packed anaerobic reactor for azo dye wastewater treatment under variable influent quality.

PubMed

Zhang, Yaobin; Liu, Yiwen; Jing, Yanwen; Zhao, Zhiqiang; Quan, Xie

2012-01-01

Zero valent iron (ZVI) is expected to help create an enhanced anaerobic environment that might improve the performance of anaerobic treatment. Based on this idea, a novel ZVI packed upflow anaerobic sludge blanket (ZVI-UASB) reactor was developed to treat azo dye wastewater with variable influent quality. The results showed that the reactor was less influenced by increases of Reactive Brilliant Red X-3B concentration from 50 to 1000 mg/L and chemical oxygen demand (COD) from 1000 to 7000 mg/L in the feed than a reference UASB reactor without the ZVI. The ZVI decreased oxidation-reduction potential in the reactor by about 80 mV. Iron ion dissolution from the ZVI could buffer acidity in the reactor, the amount of which was related to the COD concentration. Fluorescence in situ hybridization test showed the abundance of methanogens in the sludge of the ZVI-UASB reactor was significantly greater than that of the reference one. Denaturing gradient gel electrophoresis showed that the ZVI increased the diversity of microbial strains responsible for high efficiency.

Anaerobic digestion of olive oil mill effluents together with swine manure in UASB reactors.

PubMed

Aangelidaki, I; Ahrin, B K; Deng, H; Schmidt, J E

2002-01-01

Combined anaerobic digestion of olive oil mill effluent (OME) with swine manure, was investigated. In batch experiments was shown that for anaerobic degradation of OME alone nitrogen addition was needed. A COD:N ratio in the range of 65:1 to 126:1 was necessary for the optimal degradation process. Furthermore, it was found that methane productions rates during digestion of either swine manure alone or OME alone were much lower than the rates achieved when OME and manure were digested together. Admixing OME with manure at a concentration of 5 to 10% OME resulted in the highest methane production rates. Using upflow anaerobic sludge blanket (UASB) reactors, it was shown that codigestion of OME with swine manure (up to 50% OME) was successful with a COD reduction up to 75%. The process was adapted for degradation of OME with stepwise increase of the OME load to the UASB reactor. The results showed that the high content of ammonia in swine manure, together with content of other nutrients, make it possible to degrade OME without addition of external alkalinity and without addition of external nitrogen source. Anaerobic treatment of OME in UASB reactors resulted in reduction of simple phenolic compounds such as mequinol, phenyl ethyl alcohol and ethyl methyl phenol. After anaerobic treatment the concentration of these compounds was reduced between 75 and 100%. However, the concentration of some degradation products such as methyl phenol and ethyl phenol were detected in significantly higher concentrations after treatment, indicating that the process has to be further optimised to achieve satisfactory removal of all xenobiotic compounds.

Significance of dissolved methane in effluents of anaerobically treated low strength wastewater and potential for recovery as an energy product: A review.

PubMed

Crone, Brian C; Garland, Jay L; Sorial, George A; Vane, Leland M

2016-11-01

The need for energy efficient Domestic Wastewater (DWW) treatment is increasing annually with population growth and expanding global energy demand. Anaerobic treatment of low strength DWW produces methane which can be used to as an energy product. Temperature sensitivity, low removal efficiencies (Chemical Oxygen Demand (COD), Suspended Solids (SS), and Nutrients), alkalinity demand, and potential greenhouse gas (GHG) emissions have limited its application to warmer climates. Although well designed anaerobic Membrane Bioreactors (AnMBRs) are able to effectively treat DWW at psychrophilic temperatures (10-30 °C), lower temperatures increase methane solubility leading to increased energy losses in the form of dissolved methane in the effluent. Estimates of dissolved methane losses are typically based on concentrations calculated using Henry's Law but advection limitations can lead to supersaturation of methane between 1.34 and 6.9 times equilibrium concentrations and 11-100% of generated methane being lost in the effluent. In well mixed systems such as AnMBRs which use biogas sparging to control membrane fouling, actual concentrations approach equilibrium values. Non-porous membranes have been used to recover up to 92.6% of dissolved methane and well suited for degassing effluents of Upflow Anaerobic Sludge Blanket (UASB) reactors which have considerable solids and organic contents and can cause pore wetting and clogging in microporous membrane modules. Microporous membranes can recover up to 98.9% of dissolved methane in AnMBR effluents which have low COD and SS concentrations. Sequential Down-flow Hanging Sponge (DHS) reactors have been used to recover between 57 and 88% of dissolved methane from Upflow Anaerobic Sludge Blanket (UASB) reactor effluent at concentrations of greater than 30% and oxidize the rest for a 99% removal of total dissolved methane. They can also remove 90% of suspended solids and COD in UASB effluents and produce a high quality effluent. In

Phenotypic properties and microbial diversity of methanogenic granules from a full-scale upflow anaerobic sludge bed reactor treating brewery wastewater.

PubMed

Díaz, Emiliano E; Stams, Alfons J M; Amils, Ricardo; Sanz, José L

2006-07-01

Methanogenic granules from an anaerobic bioreactor that treated wastewater of a beer brewery consisted of different morphological types of granules. In this study, the microbial compositions of the different granules were analyzed by molecular microbiological techniques: cloning, denaturing gradient gel electrophoresis and fluorescent in situ hybridization (FISH), and scanning and transmission electron microscopy. We propose here that the different types of granules reflect the different stages in the life cycle of granules. Young granules were small, black, and compact and harbored active cells. Gray granules were the most abundant granules. These granules have a multilayer structure with channels and void areas. The core was composed of dead or starving cells with low activity. The brown granules, which were the largest granules, showed a loose and amorphous structure with big channels that resulted in fractured zones and corresponded to the older granules. Firmicutes (as determined by FISH) and Nitrospira and Deferribacteres (as determined by cloning and sequencing) were the predominant Bacteria. Remarkably, Firmicutes could not be detected in the brown granules. The methanogenic Archaea identified were Methanosaeta concilii (70 to 90% by FISH and cloning), Methanosarcina mazei, and Methanospirillum spp. The phenotypic appearance of the granules reflected the physiological condition of the granules. This may be valuable to easily select appropriate seed sludges to start up other reactors.

Anaerobic on-site black water and kitchen waste treatment using UASB-septic tanks at low temperatures.

PubMed

Luostarinen, S; Rintala, J

2006-01-01

Anaerobic on-site treatment of black water (BW) and a mixture of black water and kitchen waste (BWKW) was studied in a two-phased upflow anaerobic sludge blanket septic tank (UASBst) at 10-20 degrees C. The processes were fed either continuously or discontinuously (twice per weekday). Moreover, BWKW was post-treated for nitrogen removal in an intermittently aerated moving bed biofilm reactor (MBBR) at 20 degrees C. Removal of total chemical oxygen demand (COD1) was efficient at minimum 90% with all three UASBst at all temperatures. Removal of dissolved COD (CODdis) was also high at approx. 70% with continuously fed BW and discontinuously fed BWKW, while with discontinuous BW feeding it was 20%. Temperature decrease had little effect on COD removals, though the need for phase 2 increased with decreasing temperature, especially with BWKW. Post-treatment of BWKW in MBBR resulted in approx. 50% nitrogen removal, but suffered from lack of carbon for denitrification. With carbon addition, removal of ca. 83% was achieved.

Kinetic of carbonaceous substrate in an upflow anaerobic sludge sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP).

PubMed

Sponza, Delia Teresa; Uluköy, Ayşen

2008-01-01

The performance of an upflow anaerobic sludge blanket (UASB) reactor treating 2,4 dichlorophenol (2,4 DCP) was evaluated at different hydraulic retention times (HRTs) using synthetic wastewater in order to obtain the growth substrate (glucose-COD) and 2,4 DCP removal kinetics. Treatment efficiencies of the UASB reactor were investigated at different hydraulic retention times (2-20 h) corresponding to a food to mass (F/M) ratio of 1.2-1.92 g-COD g(-1) VSS day(-1). A total of 65-83% COD removal efficiencies were obtained at HRTs of 2-20 h. In all, 83% and 99% 2,4 DCP removals were achieved at the same HRTs in the UASB reactor. Conventional Monod, Grau Second-order and Modified Stover-Kincannon models were applied to determine the substrate removal kinetics of the UASB reactor. The experimental data obtained from the kinetic models showed that the Monod kinetic model is more appropriate for correlating the substrate removals compared to the other models for the UASB reactor. The maximum specific substrate utilization rate (k) (mg-COD mg(-1) SS day(-1)), half-velocity concentration (K(s)) (mg COD l(-1)), growth yield coefficient (Y) (mg mg(-1)) and bacterial decay coefficient (b) (day(-1)) were 0.954 mg-COD mg(-1) SS day(-1), 560.29 mg-COD l(-1), 0.78 mg-SS g(-1)-COD, 0.093 day(-1) in the Conventional Monod kinetic model. The second-order kinetic coefficient (k(2)) was calculated as 0.26 day(-1) in the Grau reaction kinetic model. The maximum COD removal rate constant (U(max)) and saturation value (K(B)) were calculated as 7.502 mg CODl(-1)day(-1) and 34.56 mg l(-1)day(-1) in the Modified Stover-Kincannon Model. The (k)(mg-2,4 DCP mg(-1) SS day(-1)), (K(s)) (mg 2,4 DCPl(-1)), (Y) (mg SS mg(-1) 2,4 DCP) and (k(d)) (day(-1)) were 0.0041 mg-2,4 DCP mg(-1) SS day(-1), 2.06 mg-COD l(-1), 0.0017 mg-SS mg(-1) 2,4 DCP and 3.1 x 10(-5) day(-1) in the Conventional Monod kinetic model for 2,4 DCP degradation. The second-order kinetic coefficient (k(2)) was calculated as 0.30 day

A study of energy-size relationship and wear rate in a lab-scale high pressure grinding rolls unit

NASA Astrophysics Data System (ADS)

Rashidi Dashtbayaz, Samira

This study is focused on two independent topics of energy-size relationship and wear-rate measurements on a lab-scale high pressure grinding rolls (HPGR). The first part of this study has been aimed to investigate the influence of the operating parameters and the feed characteristics on the particle-bed breakage using four different ore samples in a 200 mm x 100 mm lab-scale HPGR. Additionally, multistage grinding, scale-up from a lab-scale HPGR, and prediction of the particle size distributions have been studied in detail. The results obtained from energy-size relationship studies help with better understanding of the factors contributing to more energy-efficient grinding. It will be shown that the energy efficiency of the two configurations of locked-cycle and open multipass is completely dependent on the ore properties. A test procedure to produce the scale-up data is presented. The comparison of the scale-up factors between the data obtained on the University of Utah lab-scale HPGR and the industrial machine at the Newmont Boddington plant confirmed the applicability of lab-scale machines for trade-off studies. The population balance model for the simulation of product size distributions has shown to work well with the breakage function estimated through tests performed on the HPGR at high rotational speed. Selection function has been estimated by back calculation of population balance model with the help of the experimental data. This is considered to be a major step towards advancing current research on the simulation of particle size distribution by using the HPGR machine for determining the breakage function. Developing a technique/setup to measure the wear rate of the HPGR rolls' surface is the objective of the second topic of this dissertation. A mockup was initially designed to assess the application of the linear displacement sensors for measuring the rolls' weight loss. Upon the analysis of that technique and considering the corresponding sources of

Anaerobic co-digestion of Tunisian green macroalgae Ulva rigida with sugar industry wastewater for biogas and methane production enhancement.

PubMed

Karray, Raida; Karray, Fatma; Loukil, Slim; Mhiri, Najla; Sayadi, Sami

2017-03-01

Ulva rigida is a green macroalgae, abundantly available in the Mediterranean which offers a promising source for the production of valuable biomaterials, including methane. In this study, anaerobic digestion assays in a batch mode was performed to investigate the effects of various inocula as a mixture of fresh algae, bacteria, fungi and sediment collected from the coast of Sfax, on biogas production from Ulva rigida. The results revealed that the best inoculum to produce biogas and feed an anaerobic reactor is obtained through mixing decomposed macroalgae with anaerobic sludge and water, yielding into 408mL of biogas. The process was then investigated in a sequencing batch reactor (SBR) which led to an overall biogas production of 375mL with 40% of methane. Further co-digestion studies were performed in an anaerobic up-flow bioreactor using sugar wastewater as a co-substrate. A high biogas production yield of 114mL g -1 VS added was obtained with 75% of methane. The co-digestion proposed in this work allowed the recovery of natural methane, providing a promising alternative to conventional anaerobic microbial fermentation using Tunisian green macroalgae. Finally, in order to identify the microbial diversity present in the reactor during anaerobic digestion of Ulva rigida, the prokaryotic diversity was investigated in this bioreactor by the denaturing gradient gel electrophoresis (DGGE) method targeting the 16S rRNA gene. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transfer of tracers and pesticides in lab scale wetland systems: the role of vegetation

NASA Astrophysics Data System (ADS)

Durst, R.; Imfeld, G.; Lange, J.

2012-04-01

Surface wetlands can collect contaminated runoff from urban or agricultural catchments and have intrinsic physical, chemical and biological retention and removal processes useful for mitigating contaminants, including pesticides, and thus limiting the contamination of aquatic ecosystems. Yet little is known about the transfer of pesticides between wetlands collecting pesticides runoff and groundwater, and the subsequent threat of groundwater contamination. In particular, the influence of wetland vegetation and related processes during pesticide transfer is largely unknown. Here we evaluate the transfer of the widely used herbicide Isoproturon (IPU) and the fungicide Metalaxyl (MTX) with that of Uranine (UR) and Sulphorhodamine (SRB) in a vegetated and a non-vegetated lab-scale wetland. UR and SRB had successfully served as a reference for pesticides in surface wetlands. We filled two 65 cm long and 15 cm diameter borosilicate columns with sediment cores from a wetland, one without and one with vegetation (Phragmites australis, Cav.). When a constant flow-through rate of 0.33 ml min-1 was reached, tracers and pesticides were injected simultaneously and continuously. The hydrological mass balance and tracer concentrations were measured daily at the outlet of the lab-scale wetland. Samples for pesticides and hydrochemical analyses were collected biweekly. The lab-scale wetlands were covered to limit evaporation and light decay of injected compounds. The reactive transfer of compounds in the vegetated and non-vegetated lab-scale wetland was compared based on breakthrough curves (BTC's) and model parameters of the lumped parameter model CXTFIT. The hydrologic balance revealed that the intensity of transpiration and hence plant activity in the lab-scale wetlands progressively decreased and then apparently ceased after about eight days following continuous pesticide injection. In this first phase, no significant difference in the hydrologic balances could be observed

Kinetics and advanced digester design for anaerobic digestion of water hyacinth and primary sludge

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

Chynoweth, D.P.; Dolenc, D.A.; Ghosh, S.

1982-01-01

A research program centered around a facility located at Walt Disney World (WDW) is in progress to evaluate the use of water hyacinth (WH) for secondary and tertiary wastewater treatment, to optimize growth of WH under these conditions, and to convert the resultant primary sludge (PS) and WH to methane via anaerobic digestion. This article describes the status of the biogasification component of this program, which includes baseline and advanced digestion experiments with individual feeds and blends and the design of an experimental test unit (ETU) to be installed at WDW. Experiments with several blends demonstrated that methane yields canmore » be predicted from the fractional content and methane yield of each component. The process was found to adhere to the Monod kinetic model for microbial growth, and associated kinetic parameters were developed for various feed combinations. A novel upflow digester is achieving significantly higher conversion than a stirred-tank digester. Of several pretreatment techniques used, only alkaline treatment resulted in increased biodegradability. A larger scale (4.5 m/sup 3/) experimental test unit is being designed for installation at WDW in 1982. 13 figures, 4 tables.« less

Structures of microbial communities found in anaerobic batch runs that produce methane from propionic acid--Seeded from full-scale anaerobic digesters above a certain threshold.

PubMed

Kim, Woong; Shin, Seung Gu; Han, Gyuseong; Cho, Kyungjin; Hwang, Seokhwan

2015-11-20

The volatile fatty acid propionate inhibits anaerobic digestion during organic waste treatments. To examine potential microbial interactions that accelerate propionate oxidation, anaerobic digestion systems seeded with various types of anaerobic sludge were analyzed. Seed samples were collected from 10 different full-scale anaerobic reactors in South Korea. Propionate oxidation was estimated as the methane production rate per gram of propionate used per day. Two domestic sewage sludge showed the highest methane production rate values, 109.1 ± 4.2 and 74.5 ± 8.6 mL CH4/(g propionate ∙ d). A food waste recycling wastewater source exhibited the lowest methane production rate, 33.2 ± 2.6 mL CH4/(g propionate ∙ d). To investigate how the microbial community structure affected propionate oxidation, qualitative molecular analyses were carried out using denaturing gradient gel electrophoresis. Methanosaeta concilii, an aceticlastic methanogen, was detected in most batch runs. Smithella propionica, a unique propionate oxidizer and simultaneous producer of acetate, was found in domestic sewage sludge sources showing the highest methane production rate; in contrast, Desulfobulbus rhabdoformis, a sulfate reducer coupled with the consumption of acetate to be used as a precursor of methane, was observed in food waste recycling wastewater sludge source showing the lowest methane production rate. Thus, we propose that S. propionica, a syntrophic acetate producer using propionate, might cooperate with aceticlastic methanogens for high methane production during anaerobic digestion that included propionate. Copyright © 2015 Elsevier B.V. All rights reserved.

A new method of two-phase anaerobic digestion for fruit and vegetable waste treatment.

PubMed

Wu, Yuanyuan; Wang, Cuiping; Liu, Xiaoji; Ma, Hailing; Wu, Jing; Zuo, Jiane; Wang, Kaijun

2016-07-01

A novel method of two-phase anaerobic digestion where the acid reactor is operated at low pH 4.0 was proposed and investigated. A completely stirred tank acid reactor and an up-flow anaerobic sludge bed methane reactor were operated to examine the possibility of efficient degradation of lactate and to identify their optimal operating conditions. Lactate with an average concentration of 14.8g/L was the dominant fermentative product and Lactobacillus was the predominant microorganism in the acid reactor. The effluent from the acid reactor was efficiently degraded in the methane reactor and the average methane yield was 261.4ml/gCOD removed. Organisms of Methanosaeta were the predominant methanogen in granular sludge of methane reactor, however, after acclimation hydrogenotrophic methanogens enriched, which benefited for the conversion of lactate to acetate. The two-phase AD system exhibited a low hydraulic retention time of 3.56days and high methane yield of 348.5ml/g VS removed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anisotropic ion heating and BBELF waves within the low-altitude ion upflow region

NASA Astrophysics Data System (ADS)

Shen, Y.; Knudsen, D. J.; Burchill, J. K.; James, H. G.; Miles, D. M.

2016-12-01

Previous studies have shown that low-energy (<10 eV) ion upflow energization processes involve multiple steps. At the initial stage, contributions from transverse-to-B ion heating by wave-particle interaction (WPI) are often underestimated. The wave-generation mechanisms, the specific wave modes leading to the ion heating, and the minimum altitude where WPI takes place remain unresolved. With this in mind, we statistically investigate the relation between anisotropic ion temperature enhancements and broadband extremely low frequency (BBELF) wave emissions within the ion upflow region using data from the Suprathermal Electron imager (SEI), the Fluxgate Magnetometer (MGF), and the Radio Receiver Instrument (RRI) onboard the e-POP satellite. Initial results demonstrate that perpendicular-to-B ion temperatures can reach up to 4.3 eV in approximately 1 km wide spatial region near 410 km altitude inside an active auroral surge. Intense small-scale field-aligned currents (FACs) as well as strong BBELF wave emissions, comprising electromagnetic waves below 80 Hz and electrostatic waves above, accompany these ion heating events. The minimum altitude of potential WPI reported here is lower than as previously suggested as 520 km by Frederick-Frost et al. 2007. We measure polarization and power spectral density for specific wave modes to explore the nature of ion heating within the BBELF waves. Acknowledgement: This research is supported by an Eyes High Doctoral Recruitment Scholarship at University of Calgary.

Buoyant Filter Bio-Reactor (BFBR)--a novel anaerobic wastewater treatment unit.

PubMed

Panicker, Soosan J; Philipose, M C; Haridas, Ajit

2008-01-01

The Buoyant Filter Bio-Reactor (BFBR) is a novel and very efficient method for the treatment of complex wastewater. Sewage is a complex wastewater containing insoluble COD contributed by fat and proteins. The fat and proteins present in the domestic sewage cause operational problems and underperformance in the Upflow Anaerobic Sludge Blanket Reactor, used now for treating sewage anaerobically. The biogas yield from the BFBR is 0.36 m3/kg COD reduced and the methane content was about 70-80%. Production of methane by anaerobic digestion of organic waste had the benefit of lower energy costs for treatment and is thus environmentally beneficial to the society by providing a clean fuel from renewable feed stocks. The BFBR achieved a COD removal efficiency of 80-90% for an organic loading rate of 4.5 kg/m3/d at a hydraulic retention time of 3.25 hours. The effluent COD was less than 100 mg/l, thus saving on secondary treatment cost. No pretreatment like sedimentation was required for the influent to the BFBR. The BFBR can produce low turbidity effluent as in the activated sludge process (ASP). The land area required for the BFBR treatment plant is less when compared to ASP plant. Hence the problem of scarcity of land for the treatment plant is reduced. The total expenditure for erecting the unit was less than 50% as that of conventional ASP for the same COD removal efficiency including land cost. IWA Publishing 2008.

Qualitative Analysis of Microbial Dynamics during Anaerobic Digestion of Microalgal Biomass in a UASB Reactor

PubMed Central

Doloman, Anna; Soboh, Yousef; Walters, Andrew J.; Sims, Ronald C.

2017-01-01

Anaerobic digestion (AD) is a microbiologically coordinated process with dynamic relationships between bacterial players. Current understanding of dynamic changes in the bacterial composition during the AD process is incomplete. The objective of this research was to assess changes in bacterial community composition that coordinates with anaerobic codigestion of microalgal biomass cultivated on municipal wastewater. An upflow anaerobic sludge blanket reactor was used to achieve high rates of microalgae decomposition and biogas production. Samples of the sludge were collected throughout AD and extracted DNA was subjected to next-generation sequencing using methanogen mcrA gene specific and universal bacterial primers. Analysis of the data revealed that samples taken at different stages of AD had varying bacterial composition. A group consisting of Bacteroidales, Pseudomonadales, and Enterobacteriales was identified to be putatively responsible for the hydrolysis of microalgal biomass. The methanogenesis phase was dominated by Methanosarcina mazei. Results of observed changes in the composition of microbial communities during AD can be used as a road map to stimulate key bacterial species identified at each phase of AD to increase yield of biogas and rate of substrate decomposition. This research demonstrates a successful exploitation of methane production from microalgae without any biomass pretreatment. PMID:29259629

Anaerobic digestibility of beef hooves with swine manure or slaughterhouse sludge.

PubMed

Xia, Yun; Wang, Ding-Kang; Kong, Yunhong; Ungerfeld, Emilio M; Seviour, Robert; Massé, Daniel I

2015-04-01

Anaerobic digestion is an effective method for treating animal by-products, generating at the same time green energy as methane (CH4). However, the methods and mechanisms involved in anaerobic digestion of α-keratin wastes like hair, nails, horns and hooves are still not clear. In this study we investigated the feasibility of anaerobically co-digesting ground beef hooves in the presence of swine manure or slaughterhouse sludge at 25 °C using eight 42-L Plexiglas lab-scale digesters. Our results showed addition of beef hooves statistically significantly increased the rate of CH4 production with swine manure, but only increased it slightly with slaughterhouse sludge. After 90-day digestion, 73% of beef hoof material added to the swine manure-inoculated digesters had been converted into CH4, which was significantly higher than the 45% level achieved in the slaughterhouse sludge inoculated digesters. BODIPY-Fluorescent casein staining detected proteolytic bacteria in all digesters with and without added beef hooves, and their relative abundances corresponded to the rate of methanogenesis of the digesters with the different inocula. Fluorescence in situ hybridization in combination with BODIPY-Fluorescent casein staining identified most proteolytic bacteria as members of genus Alkaliphilus in the subfamily Clostridiaceae 2 of family Clostridiaceae. They thus appear to be the bacteria mainly responsible for digestion of beef hooves. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Nitrogen and phosphorus removal in pilot-scale anaerobic-anoxic oxidation ditch system.

PubMed

Peng, Yongzhen; Hou, Hongxun; Wang, Shuying; Cui, Youwei; Zhiguo, Yuan

2008-01-01

To achieve high efficiency of nitrogen and phosphorus removal and to investigate the rule of simultaneous nitrification and denitrification phosphorus removal (SNDPR), a whole course of SNDPR damage and recovery was studied in a pilot-scale, anaerobic-anoxic oxidation ditch (OD), where the volumes of anaerobic zone, anoxic zone, and ditches zone of the OD system were 7, 21, and 280 L, respectively. The reactor was fed with municipal wastewater with a flow rate of 336 L/d. The concept of simultaneous nitrification and denitrification (SND) rate (r(SND)) was put forward to quantify SND. The results indicate that: (1) high nitrogen and phosphorus removal efficiencies were achieved during the stable SND phase, total nitrogen (TN) and total phosphate (TP) removal rates were 80% and 85%, respectively; (2) when the system was aerated excessively, the stability of SND was damaged, and r(SND) dropped from 80% to 20% or less; (3) the natural logarithm of the ratio of NO(x) to NH4+ in the effluent had a linear correlation to oxidation-reduction potential (ORP); (4) when NO3- was less than 6 mg/L, high phosphorus removal efficiency could be achieved; (5) denitrifying phosphorus removal (DNPR) could take place in the anaerobic-anoxic OD system. The major innovation was that the SND rate was devised and quantified.

Comparison of lab, pilot, and industrial scale low consistency mechanical refining for improvements in enzymatic digestibility of pretreated hardwood.

PubMed

Jones, Brandon W; Venditti, Richard; Park, Sunkyu; Jameel, Hasan

2014-09-01

Mechanical refining has been shown to improve biomass enzymatic digestibility. In this study industrial high-yield sodium carbonate hardwood pulp was subjected to lab, pilot and industrial refining to determine if the mechanical refining improves the enzymatic hydrolysis sugar conversion efficiency differently at different refining scales. Lab, pilot and industrial refining increased the biomass digestibility for lignocellulosic biomass relative to the unrefined material. The sugar conversion was increased from 36% to 65% at 5 FPU/g of biomass with industrial refining at 67.0 kWh/t, which was more energy efficient than lab and pilot scale refining. There is a maximum in the sugar conversion with respect to the amount of refining energy. Water retention value is a good predictor of improvements in sugar conversion for a given fiber source and composition. Improvements in biomass digestibility with refining due to lab, pilot plant and industrial refining were similar with respect to water retention value. Published by Elsevier Ltd.

Biological treatment of TMAH (tetra-methyl ammonium hydroxide) in a full-scale TFT-LCD wastewater treatment plant.

PubMed

Hu, Tai-Ho; Whang, Liang-Ming; Liu, Pao-Wen Grace; Hung, Yu-Ching; Chen, Hung-Wei; Lin, Li-Bin; Chen, Chia-Fu; Chen, Sheng-Kun; Hsu, Shu Fu; Shen, Wason; Fu, Ryan; Hsu, Romel

2012-06-01

This study evaluated biological treatment of TMAH in a full-scale methanogenic up-flow anaerobic sludge blanket (UASB) followed by an aerobic bioreactor. In general, the UASB was able to perform a satisfactory TMAH degradation efficiency, but the effluent COD of the aerobic bioreactor seemed to increase with an increased TMAH in the influent wastewater. The batch test results confirmed that the UASB sludge under methanogenic conditions would be favored over the aerobic ones for TMAH treatment due to its superb ability of handling high strength of TMAH-containing wastewaters. Based on batch experiments, inhibitory chemicals present in TFT-LCD wastewater like surfactants and sulfate should be avoided to secure a stable methanogenic TMAH degradation. Finally, molecular monitoring of Methanomethylovorans hollandica and Methanosarcina mazei in the full-scale plant, the dominant methanogens in the UASB responsible for TMAH degradation, may be beneficial for a stable TMAH treatment performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

PubMed

Luostarinen, Sari A; Rintala, Jukka A

2005-01-01

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

Hydrogen generation via anaerobic fermentation of paper mill wastes.

PubMed

Valdez-Vazquez, Idania; Sparling, Richard; Risbey, Derek; Rinderknecht-Seijas, Noemi; Poggi-Varaldo, Héctor M

2005-11-01

The objective of this work was to determine the hydrogen production from paper mill wastes using microbial consortia of solid substrate anaerobic digesters. Inocula from mesophilic, continuous solid substrate anaerobic digestion (SSAD) reactors were transferred to small lab scale, batch reactors. Milled paper (used as a surrogate paper waste) was added as substrate and acetylene or 2-bromoethanesulfonate (BES) was spiked for methanogenesis inhibition. In the first phase of experiments it was found that acetylene at 1% v/v in the headspace was as effective as BES in inhibiting methanogenic activity. Hydrogen gas accumulated in the headspace of the bottles, reaching a plateau. Similar final hydrogen concentrations were obtained for reactors spiked with acetylene and BES. In the second phase of tests the headspace of the batch reactors was flushed with nitrogen gas after the first plateau of hydrogen was reached, and subsequently incubated, with no further addition of inhibitor nor substrate. It was found that hydrogen production resumed and reached a second plateau, although somewhat lower than the first one. This procedure was repeated a third time and an additional amount of hydrogen was obtained. The plateaux and initial rates of hydrogen accumulation decreased in each subsequent incubation cycle. The total cumulative hydrogen harvested in the three cycles was much higher (approx. double) than in the first cycle alone. We coined this procedure as IV-SSAH (intermittently vented solid substrate anaerobic hydrogen generation). Our results point out to a feasible strategy for obtaining higher hydrogen yields from the fermentation of industrial solid wastes, and a possible combination of waste treatment processes consisting of a first stage IV-SSAH followed by a second SSAD stage. Useful products of this approach would be hydrogen, organic acids or methane, and anaerobic digestates that could be used as soil amenders after post-treatment.

Effects of Predation by Protists on Prokaryotic Community Function, Structure, and Diversity in Anaerobic Granular Sludge.

PubMed

Hirakata, Yuga; Oshiki, Mamoru; Kuroda, Kyohei; Hatamoto, Masashi; Kubota, Kengo; Yamaguchi, Takashi; Harada, Hideki; Araki, Nobuo

2016-09-29

Predation by protists is top-down pressure that regulates prokaryotic abundance, community function, structure, and diversity in natural and artificial ecosystems. Although the effects of predation by protists have been studied in aerobic ecosystems, they are poorly understood in anoxic environments. We herein studied the influence of predation by Metopus and Caenomorpha ciliates-ciliates frequently found in anoxic ecosystems-on prokaryotic community function, structure, and diversity. Metopus and Caenomorpha ciliates were cocultivated with prokaryotic assemblages (i.e., anaerobic granular sludge) in an up-flow anaerobic sludge blanket (UASB) reactor for 171 d. Predation by these ciliates increased the methanogenic activities of granular sludge, which constituted 155% of those found in a UASB reactor without the ciliates (i.e., control reactor). Sequencing of 16S rRNA gene amplicons using Illumina MiSeq revealed that the prokaryotic community in the UASB reactor with the ciliates was more diverse than that in the control reactor; 2,885-3,190 and 2,387-2,426 operational taxonomic units (>97% sequence similarities), respectively. The effects of predation by protists in anaerobic engineered systems have mostly been overlooked, and our results show that the influence of predation by protists needs to be examined and considered in the future for a better understanding of prokaryotic community structure and function.

Effect of upflow velocity on the performance of an inclined plate membrane bioreactor treating municipal wastewater.

PubMed

Fontanos, P M; Yamamoto, K; Nakajima, F

2011-01-01

An inclined plate membrane bioreactor (iPMBR) was introduced to meet the challenge of handling high mixed liquor suspended solids when operating at long sludge retention times. During the first 407 days of operation, the iPMBR was able to rezone more sludge (1.5-10.5 times greater) in its upstream, anoxic tank compared to its downstream, aerobic tank. This could extend membrane filtration by diverting most of the sludge from the aerobic zone. During this period, the upflow velocities through the inclined plates of the anoxic tank ranged from 2.3 x 10(-4) to 7.7 x 10(-4) m/s. After Day 407, the operating conditions were changed to determine whether the iPMBR would fail to create a sludge concentration difference between its two tanks. When the upflow velocity was increased to 1.8 x 10(-3) m/s, the sludge concentration difference between the two zones was removed. This indicated that the upflow velocity had increased sufficiently to overcome the settling velocities of most flocs, resulting in more solids being carried from the anoxic to the aerobic tank. For the configuration of this iPMBR, operating at flow rates where the upflow velocity through the inclined plates was less than 1.0 x 10(-3) m/s would be necessary to keep a significant sludge concentration difference between its two zones.

Heat transfer analysis of a lab scale solar receiver using the discrete ordinates model

NASA Astrophysics Data System (ADS)

Dordevich, Milorad C. W.

This thesis documents the development, implementation and simulation outcomes of the Discrete Ordinates Radiation Model in ANSYS FLUENT simulating the radiative heat transfer occurring in the San Diego State University lab-scale Small Particle Heat Exchange Receiver. In tandem, it also serves to document how well the Discrete Ordinates Radiation Model results compared with those from the in-house developed Monte Carlo Ray Trace Method in a number of simplified geometries. The secondary goal of this study was the inclusion of new physics, specifically buoyancy. Implementation of an additional Monte Carlo Ray Trace Method software package known as VEGAS, which was specifically developed to model lab scale solar simulators and provide directional, flux and beam spread information for the aperture boundary condition, was also a goal of this study. Upon establishment of the model, test cases were run to understand the predictive capabilities of the model. It was shown that agreement within 15% was obtained against laboratory measurements made in the San Diego State University Combustion and Solar Energy Laboratory with the metrics of comparison being the thermal efficiency and outlet, wall and aperture quartz temperatures. Parametric testing additionally showed that the thermal efficiency of the system was very dependent on the mass flow rate and particle loading. It was also shown that the orientation of the small particle heat exchange receiver was important in attaining optimal efficiency due to the fact that buoyancy induced effects could not be neglected. The analyses presented in this work were all performed on the lab-scale small particle heat exchange receiver. The lab-scale small particle heat exchange receiver is 0.38 m in diameter by 0.51 m tall and operated with an input irradiation flux of 3 kWth and a nominal mass flow rate of 2 g/s with a suspended particle mass loading of 2 g/m3. Finally, based on acumen gained during the implementation and development

Enrichment of acetogenic bacteria in high rate anaerobic reactors under mesophilic and thermophilic conditions.

PubMed

Ryan, P; Forbes, C; McHugh, S; O'Reilly, C; Fleming, G T A; Colleran, E

2010-07-01

The objective of the current study was to expand the knowledge of the role of acetogenic Bacteria in high rate anaerobic digesters. To this end, acetogens were enriched by supplying a variety of acetogenic growth supportive substrates to two laboratory scale high rate upflow anaerobic sludge bed (UASB) reactors operated at 37 degrees C (R1) and 55 degrees C (R2). The reactors were initially fed a glucose/acetate influent. Having achieved high operational performance and granular sludge development and activity, both reactors were changed to homoacetogenic bacterial substrates on day 373 of the trial. The reactors were initially fed with sodium vanillate as a sole substrate. Although % COD removal indicated that the 55 degrees C reactor out performed the 37 degrees C reactor, effluent acetate levels from R2 were generally higher than from R1, reaching values as high as 5023 mg l(-1). Homoacetogenic activity in both reactors was confirmed on day 419 by specific acetogenic activity (SAA) measurement, with higher values obtained for R2 than R1. Sodium formate was introduced as sole substrate to both reactors on day 464. It was found that formate supported acetogenic activity at both temperatures. By the end of the trial, no specific methanogenic activity (SMA) was observed against acetate and propionate indicating that the methane produced was solely by hydrogenotrophic Archaea. Higher SMA and SAA values against H(2)/CO(2) suggested development of a formate utilising acetogenic population growing in syntrophy with hydrogenotrophic methanogens. Throughout the formate trial, the mesophilic reactor performed better overall than the thermophilic reactor. Copyright 2010 Elsevier Ltd. All rights reserved.

Behaviour of molecular weight distribution for the liquid fraction of pig slurry treated by anaerobic digestion.

PubMed

Rodríguez, D C; Belmonte, M; Peñuela, G; Campos, J L; Vidal, G

2011-01-01

Pig slurry was treated in an upflow anaerobic sludge blanket (UASB) reactor. To maintain a stable operation, the organic loading rate (OLR) applied to the system was increased stepwise by decreasing the dilution ratio of the pig slurry. Finally, during the last operational stage, no dilution was applied to the influent. The reactor maintained a soluble chemical oxygen demand (CODs) removal efficiency of 82% when OLRs lower than 1.73 g CODs l(-1) d(-1) were applied, although its efficiency fell to 55% when operated at 2.48 g CODs l(-1) d(-1). System performance was not affected by the presence of free ammonia (concentrations up to 375 mg NH3 l(-1)). The distribution of the different molecular weight fractions changed significantly during anaerobic digestion. Proteins contained in the fractions higher than 10,000 Daltons are less degraded than those belonging to the lower fractions. An important percentage of both COD and BOD5 in the effluent were observed in the lowest fraction, probably caused by the presence of volatile fatty acids (VFA).

Kinetic modelling and microbial community assessment of anaerobic biphasic fixed film bioreactor treating distillery spent wash.

PubMed

Acharya, Bhavik K; Pathak, Hilor; Mohana, Sarayu; Shouche, Yogesh; Singh, Vasdev; Madamwar, Datta

2011-08-01

Anaerobic digestion, microbial community structure and kinetics were studied in a biphasic continuously fed, upflow anaerobic fixed film reactor treating high strength distillery wastewater. Treatment efficiency of the bioreactor was investigated at different hydraulic retention times (HRT) and organic loading rates (OLR 5-20 kg COD m⁻³ d⁻¹). Applying the modified Stover-Kincannon model to the reactor, the maximum removal rate constant (U(max)) and saturation value constant (K(B)) were found to be 2 kg m⁻³ d⁻¹ and 1.69 kg m⁻³ d⁻¹ respectively. Bacterial community structures of acidogenic and methanogenic reactors were assessed using culture-independent analyses. Sequencing of 16S rRNA genes exhibited a total of 123 distinct operational taxonomic units (OTUs) comprising 49 from acidogenic reactor and 74 (28 of eubacteria and 46 of archaea) from methanogenic reactor. The findings reveal the role of Lactobacillus sp. (Firmicutes) as dominant acid producing organisms in acidogenic reactor and Methanoculleus sp. (Euryarchaeotes) as foremost methanogens in methanogenic reactor. Copyright © 2011 Elsevier Ltd. All rights reserved.

New insights into enhanced anaerobic degradation of coal gasification wastewater (CGW) with the assistance of graphene.

PubMed

Zhu, Hao; Han, Yuxing; Ma, Wencheng; Han, Hongjun; Ma, Weiwei; Xu, Chunyan

2018-08-01

The up-flow anaerobic sludge blanket (UASB) system with graphene assisted was developed for coal gasification wastewater (CGW) treatment. Short-term results showed that optimal graphene addition (0.5 g/L) resulted in a more significant enhancement of methane production and chemical oxygen demand (COD) removal compared with that of the optimal activated carbon addition (10.0 g/L). Long-term results demonstrated that COD removal efficiency and methane production rate with graphene assisted achieved 64.7% and 180.5 mL/d, respectively. In addition, graphene could promote microbes accumulation and enzymes activity, resulting in higher extracellular polymeric substances (EPS) and coenzyme F 420 concentrations. X-ray Diffraction (XRD) analysis indicated that chemical of graphene changed insignificantly during the experiment. Meanwhile, with graphene assisted, cells were attached together to form microbial aggregates to facilitate sludge granulation process. Furthermore, the enriched Geobacter and Pseudomonas might perform direct interspecies electron transfer (DIET) with Methanosaeta via biological electrical connection, enhancing the anaerobic degradation of CGW. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kinetics and mass-transfer phenomena in anaerobic granular sludge.

PubMed

Gonzalez-Gil, G; Seghezzo, L; Lettinga, G; Kleerebezem, R

2001-04-20

The kinetic properties of acetate-degrading methanogenic granular sludge of different mean diameters were assessed at different up-flow velocities (V(up)). Using this approach, the influence of internal and external mass transfer could be estimated. First, the apparent Monod constant (K(S)) for each data set was calculated by means of a curve-fitting procedure. The experimental results revealed that variations in the V(up) did not affect the apparent K(S)-value, indicating that external mass-transport resistance normally can be neglected. With regard to the granule size, a clear increase in K(S) was found at increasing granule diameters. The experimental data were further used to validate a dynamic mathematical biofilm model. The biofilm model was able to describe reaction-diffusion kinetics in anaerobic granules, using a single value for the effective diffusion coefficient in the granules. This suggests that biogas formation did not influence the diffusion-rates in the granular biomass. Copyright 2001 John Wiley & Sons, Inc.

Upflow bioreactor having a septum and an auger and drive assembly

DOEpatents

Hansen, Carl S.; Hansen, Conly L.

2007-11-06

An upflow bioreactor includes a vessel having an inlet and an outlet configured for upflow operation. A septum is positioned within the vessel and defines a lower chamber and an upper chamber. The septum includes an aperture that provides fluid communication between the upper chamber and lower chamber. The bioreactor also includes an auger positioned in the aperture of the septum. The vessel includes an opening in the top for receiving the auger. The auger extends from a drive housing, which is position over the opening and provides a seal around the opening. The drive housing is adjustable relative to the vessel. The position of the auger in the aperture can be adjusted by adjusting the drive housing relative to the vessel. The auger adjustment mechanism allows the auger to be accurately positioned within the aperture. The drive housing can also include a fluid to provide an additional seal around the shaft of the auger.

mcrA Gene abundance correlates with hydrogenotrophic methane production rates in full-scale anaerobic waste treatment systems.

PubMed

Morris, R L; Tale, V P; Mathai, P P; Zitomer, D H; Maki, J S

2016-02-01

Anaerobic treatment is a sustainable and economical technology for waste stabilization and production of methane as a renewable energy. However, the process is under-utilized due to operational challenges. Organic overload or toxicants can stress the microbial community that performs waste degradation, resulting in system failure. In addition, not all methanogenic microbial communities are equally capable of consistent, maximum biogas production. Opinion varies as to which parameters should be used to monitor the fitness of digester biomass. No standard molecular tools are currently in use to monitor and compare full-scale operations. It was hypothesized that determining the number of gene copies of mcrA, a methanogen-specific gene, would positively correlate with specific methanogenic activity (SMA) rates from biomass samples from six full-scale anaerobic digester systems. Positive correlations were observed between mcrA gene copy numbers and methane production rates against H2  : CO2 and propionate (R(2)  = 0·67-0·70, P < 0·05) but not acetate (R(2)  = 0·49, P > 0·05). Results from this study indicate that mcrA gene targeted qPCR can be used as an alternate tool to monitor and compare certain methanogen communities in anaerobic digesters. Using quantitative PCR (qPCR), we demonstrate that the abundance of mcrA, a gene specific to methane producing archaea, correlated with specific methanogenic activity (SMA) measurements when H2 and CO2 , or propionate were provided as substrates. However, mcrA abundance did not correlate with SMA with acetate. SMA values are often used as a fitness indicator of anaerobic biomass. Results from qPCR can be obtained within a day while SMA analysis requires days to weeks to complete. Therefore, qPCR for mcrA abundance is a sensitive and fast method to compare and monitor the fitness of certain anaerobic biomass. As a monitoring tool, qPCR of mcrA will help anaerobic digester operators optimize treatment and encourage

Assessing Methanogenic Archaeal Community in Full Scale Anaerobic Sludge Digester Systems in Dubai, United Arab Emirates

PubMed Central

Khan, Munawwar A.; Patel, Poojabahen G.; Ganesh, Arpitha G.; Rais, Naushad; Faheem, Sultan M.; Khan, Shams T.

2018-01-01

Introduction: Anaerobic digestion for methane production comprises of an exceptionally diverse microbial consortium, a profound understanding about which is still constrained. In this study, the methanogenic archaeal communities in three full-scale anaerobic digesters of a Municipal Wastewater Treatment Plant were analyzed by Fluorescence in situ hybridization and quantitative real-time Polymerase Chain Reaction (qPCR) technique. Methods & Materials: Fluorescence in situ hybridization (FISH) was performed to detect and quantify the methanogenic Archaea in the sludge samples whereas qPCR was carried out to support the FISH analysis. Multiple probes targeting domain archaea, different orders and families of Archaea were used for the studies. Results and Discussion: In general, the aceticlastic organisms (Methanosarcinaceae & Methanosaetaceae) were more abundant than the hydrogenotrophic organisms (Methanobacteriales, Methanomicrobiales, Methanobacteriaceae & Methanococcales). Both FISH and qPCR indicated that family Methanosaetaceae was the most abundant suggesting that aceticlastic methanogenesis is probably the dominant methane production pathway in these digesters. Conclusion: Future work involving high-throughput sequencing methods and correlating archaeal communities with the main operational parameters of anaerobic digesters will help to obtain a better understanding of the dynamics of the methanogenic archaeal community in wastewater treatment plants in United Arab Emirates (UAE) which in turn would lead to improved performance of anaerobic sludge digesters. PMID:29785219

Methane-yielding microbial communities processing lactate-rich substrates: a piece of the anaerobic digestion puzzle.

PubMed

Detman, Anna; Mielecki, Damian; Pleśniak, Łukasz; Bucha, Michał; Janiga, Marek; Matyasik, Irena; Chojnacka, Aleksandra; Jędrysek, Mariusz-Orion; Błaszczyk, Mieczysław K; Sikora, Anna

2018-01-01

Anaerobic digestion, whose final products are methane and carbon dioxide, ensures energy flow and circulation of matter in ecosystems. This naturally occurring process is used for the production of renewable energy from biomass. Lactate, a common product of acidic fermentation, is a key intermediate in anaerobic digestion of biomass in the environment and biogas plants. Effective utilization of lactate has been observed in many experimental approaches used to study anaerobic digestion. Interestingly, anaerobic lactate oxidation and lactate oxidizers as a physiological group in methane-yielding microbial communities have not received enough attention in the context of the acetogenic step of anaerobic digestion. This study focuses on metabolic transformation of lactate during the acetogenic and methanogenic steps of anaerobic digestion in methane-yielding bioreactors. Methane-yielding microbial communities instead of pure cultures of acetate producers were used to process artificial lactate-rich media to methane and carbon dioxide in up-flow anaerobic sludge blanket reactors. The media imitated the mixture of acidic products found in anaerobic environments/digesters where lactate fermentation dominates in acidogenesis. Effective utilization of lactate and biogas production was observed. 16S rRNA profiling was used to examine the selected methane-yielding communities. Among Archaea present in the bioreactors, the order Methanosarcinales predominated. The acetoclastic pathway of methane formation was further confirmed by analysis of the stable carbon isotope composition of methane and carbon dioxide. The domain Bacteria was represented by Bacteroidetes , Firmicutes , Proteobacteria , Synergistetes , Actinobacteria , Spirochaetes , Tenericutes , Caldithrix , Verrucomicrobia , Thermotogae , Chloroflexi , Nitrospirae, and Cyanobacteria. Available genome sequences of species and/or genera identified in the microbial communities were searched for genes encoding the lactate

Effect of long residence time and high temperature over anaerobic biodegradation of Scenedesmus microalgae grown in wastewater.

PubMed

Greses, S; Zamorano-López, N; Borrás, L; Ferrer, J; Seco, A; Aguado, D

2018-07-15

Anaerobic digestion of indigenous Scenedesmus spp. microalgae was studied in continuous lab-scale anaerobic reactors at different temperatures (35 °C and 55 °C), and sludge retention time - SRT (50 and 70 days). Mesophilic digestion was performed in a continuous stirred-tank reactor (CSTR) and in an anaerobic membrane bioreactor (AnMBR). Mesophilic CSTR operated at 50 days SRT only achieved 11.9% of anaerobic biodegradability whereas in the AnMBR at 70 days SRT and 50 days HRT reached 39.5%, which is even higher than the biodegradability achieved in the thermophilic CSTR at 50 days SRT (30.4%). Microbial analysis revealed a high abundance of cellulose-degraders in both reactors, AnMBR (mainly composed of 9.4% Bacteroidetes, 10.1% Chloroflexi, 8.0% Firmicutes and 13.2% Thermotogae) and thermophilic CSTR (dominated by 23.8% Chloroflexi and 12.9% Firmicutes). However, higher microbial diversity was found in the AnMBR compared to the thermophilic CSTR which is related to the SRT. since high SRT promoted low growth-rate microorganisms, increasing the hydrolytic potential of the system. These results present the membrane technology as a promising approach to revalue microalgal biomass, suggesting that microalgae biodegradability and consequently the methane production could be improved operating at higher SRT. Copyright © 2018 Elsevier Ltd. All rights reserved.

Biogas generation in anaerobic wastewater treatment under tetracycline antibiotic pressure

NASA Astrophysics Data System (ADS)

Lu, Meiqing; Niu, Xiaojun; Liu, Wei; Zhang, Jun; Wang, Jie; Yang, Jia; Wang, Wenqi; Yang, Zhiquan

2016-06-01

The effect of tetracycline (TC) antibiotic on biogas generation in anaerobic wastewater treatment was studied. A lab-scale Anaerobic Baffled Reactor (ABR) with three compartments was used. The reactor was operated with synthetic wastewater in the absence of TC and in the presence of 250 μg/L TC for 90 days, respectively. The removal rate of TC, volatile fatty acids (VFAs), biogas compositions (hydrogen (H2), methane (CH4), carbon dioxide (CO2)), and total biogas production in each compartment were monitored in the two operational conditions. Results showed that the removal rate of TC was 14.97-67.97% in the reactor. The presence of TC had a large negative effect on CH4 and CO2 generation, but appeared to have a positive effect on H2 production and VFAs accumulation. This response indicated that the methanogenesis process was sensitive to TC presence, but the acidogenesis process was insensitive. This suggested that the presence of TC had less influence on the degradation of organic matter but had a strong influence on biogas generation. Additionally, the decrease of CH4 and CO2 generation and the increase of H2 and VFAs accumulation suggest a promising strategy to help alleviate global warming and improve resource recovery in an environmentally friendly approach.

Evaluation of biological hydrogen sulfide oxidation coupled with two-stage upflow filtration for groundwater treatment.

PubMed

Levine, Audrey D; Raymer, Blake J; Jahn, Johna

2004-01-01

Hydrogen sulfide in groundwater can be oxidized by aerobic bacteria to form elemental sulfur and biomass. While this treatment approach is effective for conversion of hydrogen sulfide, it is important to have adequate control of the biomass exiting the biological treatment system to prevent release of elemental sulfur into the distribution system. Pilot scale tests were conducted on a Florida groundwater to evaluate the use of two-stage upflow filtration downstream of biological sulfur oxidation. The combined biological and filtration process was capable of excellent removal of hydrogen sulfide and associated turbidity. Additional benefits of this treatment approach include elimination of odor generation, reduction of chlorine demand, and improved stability of the finished water.

Comparison of semi-batch vs. continuously fed anaerobic bioreactors for the treatment of a high-strength, solids-rich pumpkin-processing wastewater.

PubMed

del Agua, Isabel; Usack, Joseph G; Angenent, Largus T

2015-01-01

The objective of this work was to compare two different high-rate anaerobic bioreactor configurations--the anaerobic sequencing batch reactor (ASBR) and the upflow anaerobic solid removal (UASR) reactor--for the treatment of a solid-rich organic wastewater with a high strength. The two, 4.5-L reactors were operated in parallel for close to 100 days under mesophilic conditions (37°C) with non-granular biomass by feeding a pumpkin wastewater with ∼4% solids. The organic loading rate of pumpkin wastewater was increased periodically to a maximum of 8 g COD L(-1) d(-1) by shortening the hydraulic retention time to 5.3 days. Compositional analysis of pumpkin wastewater revealed deficiencies in the trace metal cobalt and alkalinity. With supplementation, the ASBR outperformed the UASR reactor with total chemical oxygen demand (COD) removal efficiencies of 64% and 53%, respectively, achieving a methane yield of 0.27 and 0.20 L CH4 g(-1) COD fed to the ASBR and UASR, respectively. The better performance realized with the ASBR and this specific wastewater was attributed to its semi-batch, dynamic operating conditions rather than the continuous operating conditions of the UASR reactor.

Model-based strategy for cell culture seed train layout verified at lab scale.

PubMed

Kern, Simon; Platas-Barradas, Oscar; Pörtner, Ralf; Frahm, Björn

2016-08-01

Cell culture seed trains-the generation of a sufficient viable cell number for the inoculation of the production scale bioreactor, starting from incubator scale-are time- and cost-intensive. Accordingly, a seed train offers potential for optimization regarding its layout and the corresponding proceedings. A tool has been developed to determine the optimal points in time for cell passaging from one scale into the next and it has been applied to two different cell lines at lab scale, AGE1.HN AAT and CHO-K1. For evaluation, experimental seed train realization has been evaluated in comparison to its layout. In case of the AGE1.HN AAT cell line, the results have also been compared to the formerly manually designed seed train. The tool provides the same seed train layout based on the data of only two batches.

Anaerobic co-digestion of dairy manure and potato waste

NASA Astrophysics Data System (ADS)

Yadanaparthi, Sai Krishna Reddy

Dairy and potato are two important agricultural commodities in Idaho. Both the dairy and potato processing industries produce a huge amount of waste which could cause environmental pollution. To minimize the impact of potential pollution associated with dairy manure (DM) and potato waste (PW), anaerobic co-digestion has been considered as one of the best treatment process. The purpose of this research is to evaluate the anaerobic co-digestion of dairy manure and potato waste in terms of process stability, biogas generation, construction and operating costs, and potential revenue. For this purpose, I conducted 1) a literature review, 2) a lab study on anaerobic co-digestion of dairy manure and potato waste at three different temperature ranges (ambient (20-25°C), mesophilic (35-37°C) and thermophilic (55-57°C) with five mixing ratios (DM:PW-100:0, 90:10, 80:20, 60:40, 40:60), and 3) a financial analysis for anaerobic digesters based on assumed different capital costs and the results from the lab co-digestion study. The literature review indicates that several types of organic waste were co-digested with DM. Dairy manure is a suitable base matter for the co-digestion process in terms of digestion process stability and methane (CH4) production (Chapter 2). The lab tests showed that co-digestion of DM with PW was better than digestion of DM alone in terms of biogas and CH4 productions (Chapter 3). The financial analysis reveals DM and PW can be used as substrate for full size anaerobic digesters to generate positive cash flow within a ten year time period. Based on this research, the following conclusions and recommendations were made: ▸ The ratio of DM:PW-80:20 is recommended at thermophilic temperatures and the ratio of DM:PW-90:10 was recommended at mesophilic temperatures for optimum biogas and CH4 productions. ▸ In cases of anaerobic digesters operated with electricity generation equipment (generators), low cost plug flow digesters (capital cost of 600/cow

Anaerobic co-digestion of sewage sludge and food waste.

PubMed

Prabhu, Meghanath S; Mutnuri, Srikanth

2016-04-01

Anaerobic co-digestion of organic matter improves digester operating characteristics and its performance. In the present work, food waste was collected from the institute cafeteria. Two types of sludge (before centrifuge and after centrifuge) were collected from the fluidised bed reactor of the institute treating sewage wastewater. Food waste and sludge were studied for their physico-chemical characteristics, such as pH, chemical oxygen demand, total solids, volatile solids, ammoniacal nitrogen, and total nitrogen. A biomethane potential assay was carried out to find out the optimum mixing ratio of food waste and sludge for anaerobic co-digestion. Results indicated that food waste mixed with sludge in the ratio of 1:2 produced the maximum biogas of 823 ml gVS(-1)(21 days) with an average methane content of 60%. Batch studies were conducted in 5 L lab-glass reactors at a mesophilic temperature. The effect of different substrate loading rates on biogas production was investigated. The mixing ratio of food waste and sludge was 1:2. A loading rate of 1 gVS L d(-1)gave the maximum biogas production of 742 ml g(-1)VS L d(-1)with a methane content of 50%, followed by 2 gVS L d(-1)with biogas of 539 ml g(-1)VS L d(-1) Microbial diversity of the reactor during fed batch studies was investigated by terminal restriction fragment length polymorphism. A pilot-scale co-digestion of food waste and sludge (before centrifuge) indicated the process stability of anaerobic digestion. © The Author(s) 2016.

Anaerobic co-digestion of microalgal biomass and wheat straw with and without thermo-alkaline pretreatment.

PubMed

Solé-Bundó, Maria; Eskicioglu, Cigdem; Garfí, Marianna; Carrère, Hélène; Ferrer, Ivet

2017-08-01

This study aimed at analyzing the anaerobic co-digestion of microalgal biomass grown in wastewater and wheat straw. To this end, Biochemical Methane Potential (BMP) tests were carried out testing different substrate proportions (20-80, 50-50 and 80-20%, on a volatile solid basis). In order to improve their biodegradability, the co-digestion of both substrates was also evaluated after applying a thermo-alkaline pretreatment (10% CaO at 75°C for 24h). The highest synergies in degradation rates were observed by adding at least 50% of wheat straw. Therefore, the co-digestion of 50% microalgae - 50% wheat straw was investigated in mesophilic lab-scale reactors. The results showed that the methane yield was increased by 77% with the co-digestion as compared to microalgae mono-digestion, while the pretreatment only increased the methane yield by 15% compared to the untreated mixture. Thus, the anaerobic co-digestion of microalgae and wheat straw was successful even without applying a thermo-alkaline pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quick-start of full-scale anaerobic digestion (AD) using aeration

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

Lagerkvist, Anders, E-mail: al@ltu.se; Pelkonen, Markku; Wikström, Tommy

Highlights: • A fast, and original, start up procedure for anaerobic digestors has been applied at full scale. • The development of a methanogenic culture has been documented using fluorescent in situ hybridization. • The technique can be widely applied. - Abstract: A conventional 1300 m{sup 3} continuously stirred anaerobic tank reactor at the city of Boden, north Sweden, which was receiving a feed of both sewage sludge and food waste, was put out of operation due to the build-up of a float phase. The reactor was emptied and cleaned. At start-up there was no methanogenic sludge available, so anmore » unconventional start-up procedure was applied: The reactor was rapidly (8 days with 1200 kg of total solids (TS) added daily) filled with thickened, and slightly acidic sewage sludge, showing only slight methane generation, which was subsequently heated to 55 °C. Then compressed air was blown into the digester and within a month a fully functional methanogenic culture was established. The transfer from acidogenic to methanogenic conditions happened in about one week. As a start-up technique this is fast and cost efficient, it only requires the access of a compressor, electricity and a source of air. In total, about 16 tonnes of oxygen were used. It is proposed that this method may also be used as an operational amendment technique, should a reactor tend to acidify.« less

Iron and manganese removal from textile effluents in anaerobic attached-growth bioreactor filled with coirfibres.

PubMed

Jayaweera, M W; Gomes, P I A; Wijeyekoon, S L J

2007-01-01

A laboratory scale study on Fe and Mn removal in upflow anaerobic bioreactor of a working volume of 20 L with coir fibre as the filter medium was investigated for a period of 312 days. The maximum Fe and Mn levels considered were 10 and 5 mg/L respectively, which are the typical average values of textile effluents subsequent to the primary and secondary treatments. Ten sub-experimental runs were conducted with varying HRTs (5 days to 1 day), ratios of COD:SO42- (20 to 3.5), Fe levels (0.005 to 10 mg/L) and Mn levels (0 to 5 mg/L). COD:SO2 of 3.5 was identified as the optimum point at which sulphate reducing bacteria (SRBs) out competed methane producing bacteria (MPBs) and further reduction of this ratio caused total and/or significant inhibition of MPBs, thus building sulphate reducing conditions. The effluent contained Fe and Mn below the permissible levels (1.6 and 1.1 mg/L for Fe and Mn, respectively) stipulated by US National Pollution Discharge Elimination System (NPDES) for inland surface waters at HRTs higher than 3 days. Results of the mass balance showed more Fe accumulation (60%) in sediments whereas 27% in the filter media. An opposite observation was noticed for Mn.

Enhancing the anaerobic digestion potential of dairy waste activated sludge by two step sono-alkalization pretreatment.

PubMed

Rani, R Uma; Kumar, S Adish; Kaliappan, S; Yeom, Ick-Tae; Banu, J Rajesh

2014-05-01

High efficiency resource recovery from dairy waste activated sludge (WAS) has been a focus of attention. An investigation into the influence of two step sono-alkalization pretreatment (using different alkaline agents, pH and sonic reaction times) on sludge reduction potential in a semi-continuous anaerobic reactor was performed for the first time in literature. Firstly, effect of sludge pretreatment was evaluated by COD solubilization, suspended solids reduction and biogas production. At optimized condition (4172 kJ/kg TS of supplied energy for NaOH - pH 10), COD solubilization, suspended solids reduction and biogas production was 59%, 46% and 80% higher than control. In order to clearly describe the hydrolysis of waste activated sludge during sono-alkalization pretreatment by a two step process, concentrations of ribonucleic acid (RNA) and bound extracellular polymeric substance (EPS) were also measured. Secondly, semi-continuous process performance was studied in a lab-scale semi-continuous anaerobic reactor (5L), with 4 L working volume. With three operated SRTs, the SRT of 15 d was found to be most appropriate for economic operation of the reactor. Combining pretreatment with anaerobic digestion led to 58% and 62% of suspended solids and volatile solids reduction, respectively, with an improvement of 83% in biogas production. Thus, two step sono-alkalization pretreatment laid the basis in enhancing the anaerobic digestion potential of dairy WAS. Copyright © 2013 Elsevier B.V. All rights reserved.

Behavior of TiO₂ nanoparticles during incineration of solid paint waste: a lab-scale test.

PubMed

Massari, Andrea; Beggio, Marta; Hreglich, Sandro; Marin, Riccardo; Zuin, Stefano

2014-10-01

In order to assess the potential impacts posed by products containing engineered nanoparticles, it is essential to generate more data about the release of these particles from products' life cycle. Although first studies were performed to investigate the release of nanoparticles from use phase, very few data are available on the potential release from recycling or disposal of nano-enhanced products. In this work, we investigated the behavior of TiO2 nanoparticles from incineration of solid paint waste containing these particles. Solid paint debris with and without TiO2 nanoparticles were treated in a lab scale incineration plant at 950°C (combustion temperature) and in oxidizing atmosphere. The obtained ashes were also vitrified with additives and the release of Ti was finally evaluated by leaching test. From our incineration lab-scale experiment, we did not observe a release of TiO2 nanoparticles into the atmosphere, and Ti was attached to the surface of obtained solid residues (i.e. ashes). The characterization of ashes showed that TiO2 nanoparticles reacted during the incineration to give calcium titanate. Finally, a very low release of Ti was measured, less 1 mg/kg, during the leaching test of ashes vitrified with glass cullet and feldspathic inert. Our work suggests that TiO2 nanoparticles added in paints may undergo to physicochemical transformation during the incineration, and that Ti found in ashes may be strongly immobilized in glass matrix. Since this conclusion is based on lab-scale experiment, further research is required to identify which nanoparticles will be emitted to the environment from a real-word-incineration system of household hazardous waste. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anaerobic Cultures from Preserved Tissues of Baby Mammoth

NASA Technical Reports Server (NTRS)

Pikuta, Elena V.; Hoover, Richard B.; Fisher, Daniel

2011-01-01

Microbiological analysis of several cold-preserved tissue samples from the Siberian baby mammoth known as Lyuba revealed a number of culturable bacterial strains that were grown on anaerobic media at 4 C. Lactic acid produced by LAB (lactic acid bacteria) group, usually by members of the genera Carnobacterium and Lactosphera, appears to be a wonderful preservative that prevents other bacteria from over-dominating a system. Permafrost and lactic acid preserved the body of this one-month old baby mammoth and kept it in exceptionally good condition, resulting in this mammoth being the most complete such specimen ever recovered. The diversity of novel anaerobic isolates was expressed on morphological, physiological and phylogenetic levels. Here we discuss the specifics of the isolation of new strains, differentiation from trivial contamination, and preliminary results for the characterization of cultures.

An integrated anaerobic digestion and UV photocatalytic treatment of distillery wastewater.

PubMed

Apollo, Seth; Onyango, Maurice S; Ochieng, Aoyi

2013-10-15

Anaerobic up-flow fixed bed reactor and annular photocatalytic reactor were used to study the efficiency of integrated anaerobic digestion (AD) and ultraviolet (UV) photodegradation of real distillery effluent and raw molasses wastewater (MWW). It was found that UV photodegradation as a stand-alone technique achieved colour removal of 54% and 69% for the distillery and MWW, respectively, with a COD reduction of <20% and a negligible BOD reduction. On the other hand, AD as a single treatment technique was found to be effective in COD and BOD reduction with efficiencies of above 75% and 85%, respectively, for both wastewater samples. However, the AD achieved low colour removal efficiency, with an increase in colour intensity of 13% recorded when treating MWW while a colour removal of 51% was achieved for the distillery effluent. The application of UV photodegradation as a pre-treatment method to the AD process reduced the COD removal and biogas production efficiency. However, an integration in which UV photodegradation was employed as a post-treatment to the AD process achieved high COD removal of above 85% for both wastewater samples, and colour removal of 88% for the distillery effluent. Thus, photodegradation can be employed as a post-treatment technique to an AD system treating distillery effluent for complete removal of the biorecalcitrant and colour imparting compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterizing the Performance of Gas-Permeable Membranes as an Ammonia Recovery Strategy from Anaerobically Digested Dairy Manure

PubMed Central

Fillingham, Melanie; Singh, Jessica; Burtt, Stephen; Crolla, Anna; Kinsley, Chris; MacDonald, J. Douglas

2017-01-01

Capturing ammonia from anaerobically digested manure could simultaneously decrease the adverse effects of ammonia inhibition on biogas production, reduce reactive nitrogen (N) loss to the environment, and produce mineral N fertilizer as a by-product. In this study, gas permeable membranes (GPM) were used to capture ammonia from dairy manure and digestate by the diffusion of gaseous ammonia across the membrane where ammonia is captured by diluted acid, forming an aqueous ammonium salt. A lab-scale prototype using tubular expanded polytetrafluoroethylene (ePTFE) GPM was used to (1) characterize the effect of total ammonium nitrogen (TAN) concentration, temperature, and pH on the ammonia capture rate using GPM, and (2) to evaluate the performance of a GPM system in conditions similar to a mesophilic anaerobic digester. The GPM captured ammonia at a rate between 2.2 and 6.3% of gaseous ammonia in the donor solution per day. Capture rate was faster in anaerobic digestate than raw manure. The ammonia capture rate could be predicted using non-linear regression based on the factors of total ammonium nitrogen concentration, temperature, and pH. This use of membranes shows promise in reducing the deleterious impacts of ammonia on both the efficiency of biogas production and the release of reactive N to the environment. PMID:28991162

Effect of feeding mode and dilution on the performance and microbial community population in anaerobic digestion of food waste.

PubMed

Park, Jong-Hun; Kumar, Gopalakrishnan; Yun, Yeo-Myeong; Kwon, Joong-Chun; Kim, Sang-Hyoun

2018-01-01

The effect of feeding mode and dilution was studied in anaerobic digestion of food waste. An upflow anaerobic digester with a settler was fed at six different organic loading rates (OLRs) from 4.6 to 8.6kgCOD/m 3 /d for 200days. The highest methane productivity of 2.78LCH 4 /L/d was achieved at 8.6kgCOD/m 3 /d during continuous feeding of diluted FW. Continuous feeding of diluted food waste showed more stable and efficient performance than stepwise feeding of undiluted food waste. Sharp increase in propionate concentration attributed towards deterioration of the digester performances in stepwise feeding of undiluted food waste. Microbial communities at various OLRs divulged that the microbial distribution in the continuous feeding of diluted food waste was not significantly perturbed despite the increase of OLR up to 8.6kgCOD/m 3 /d, which was contrast to the unstable distribution in stepwise feeding of undiluted food waste at 6.1kgCOD/m 3 /d. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparing centralised and decentralised anaerobic digestion of stillage from a large-scale bioethanol plant to animal feed production.

PubMed

Drosg, B; Wirthensohn, T; Konrad, G; Hornbachner, D; Resch, C; Wäger, F; Loderer, C; Waltenberger, R; Kirchmayr, R; Braun, R

2008-01-01

A comparison of stillage treatment options for large-scale bioethanol plants was based on the data of an existing plant producing approximately 200,000 t/yr of bioethanol and 1,400,000 t/yr of stillage. Animal feed production--the state-of-the-art technology at the plant--was compared to anaerobic digestion. The latter was simulated in two different scenarios: digestion in small-scale biogas plants in the surrounding area versus digestion in a large-scale biogas plant at the bioethanol production site. Emphasis was placed on a holistic simulation balancing chemical parameters and calculating logistic algorithms to compare the efficiency of the stillage treatment solutions. For central anaerobic digestion different digestate handling solutions were considered because of the large amount of digestate. For land application a minimum of 36,000 ha of available agricultural area would be needed and 600,000 m(3) of storage volume. Secondly membrane purification of the digestate was investigated consisting of decanter, microfiltration, and reverse osmosis. As a third option aerobic wastewater treatment of the digestate was discussed. The final outcome was an economic evaluation of the three mentioned stillage treatment options, as a guide to stillage management for operators of large-scale bioethanol plants. Copyright IWA Publishing 2008.

Substrate Type and Free Ammonia Determine Bacterial Community Structure in Full-Scale Mesophilic Anaerobic Digesters Treating Cattle or Swine Manure.

PubMed

Li, Jiabao; Rui, Junpeng; Yao, Minjie; Zhang, Shiheng; Yan, Xuefeng; Wang, Yuanpeng; Yan, Zhiying; Li, Xiangzhen

2015-01-01

The microbial-mediated anaerobic digestion (AD) process represents an efficient biological process for the treatment of organic waste along with biogas harvest. Currently, the key factors structuring bacterial communities and the potential core and unique bacterial populations in manure anaerobic digesters are not completely elucidated yet. In this study, we collected sludge samples from 20 full-scale anaerobic digesters treating cattle or swine manure, and investigated the variations of bacterial community compositions using high-throughput 16S rRNA amplicon sequencing. Clustering and correlation analysis suggested that substrate type and free ammonia (FA) play key roles in determining the bacterial community structure. The COD: [Formula: see text] (C:N) ratio of substrate and FA were the most important available operational parameters correlating to the bacterial communities in cattle and swine manure digesters, respectively. The bacterial populations in all of the digesters were dominated by phylum Firmicutes, followed by Bacteroidetes, Proteobacteria and Chloroflexi. Increased FA content selected Firmicutes, suggesting that they probably play more important roles under high FA content. Syntrophic metabolism by Proteobacteria, Chloroflexi, Synergistetes and Planctomycetes are likely inhibited when FA content is high. Despite the different manure substrates, operational conditions and geographical locations of digesters, core bacterial communities were identified. The core communities were best characterized by phylum Firmicutes, wherein Clostridium predominated overwhelmingly. Substrate-unique and abundant communities may reflect the properties of manure substrate and operational conditions. These findings extend our current understanding of the bacterial assembly in full-scale manure anaerobic digesters.

Lab-scaled model to evaluate odor and gas production from cattle confinement facilities with deep bedded packs

USDA-ARS?s Scientific Manuscript database

A lab-scaled simulated bedded pack model was developed to study air quality and nutrient composition of deep-bedded packs found in cattle monoslope facilities. This protocol has been used to effectively evaluate many different bedding materials, environmental variables (temperature, humidity), and ...

Consecutive anaerobic-aerobic treatment of the organic fraction of municipal solid waste and lignocellulosic materials in laboratory-scale landfill-bioreactors.

PubMed

Pellera, Frantseska-Maria; Pasparakis, Emmanouil; Gidarakos, Evangelos

2016-10-01

The scope of this study is to evaluate the use of laboratory-scale landfill-bioreactors, operated consecutively under anaerobic and aerobic conditions, for the combined treatment of the organic fraction of municipal solid waste (OFMSW) with two different co-substrates of lignocellulosic nature, namely green waste (GW) and dried olive pomace (DOP). According to the results such a system would represent a promising option for eventual larger scale applications. Similar variation patterns among bioreactors indicate a relatively defined sequence of processes. Initially operating the systems under anaerobic conditions would allow energetic exploitation of the substrates, while the implementation of a leachate treatment system ultimately aiming at nutrient recovery, especially during the anaerobic phase, could be a profitable option for the whole system, due to the high organic load that characterizes this effluent. In order to improve the overall effectiveness of such a system, measures towards enhancing methane contents of produced biogas, such as substrate pretreatment, should be investigated. Moreover, the subsequent aerobic phase should have the goal of stabilizing the residual materials and finally obtain an end material eventually suitable for other purposes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removal of chemical oxygen demand, nitrogen, and heavy metals using a sequenced anaerobic-aerobic treatment of landfill leachates at 10-30 degrees C.

PubMed

Kalyuzhnyi, Sergey; Gladchenko, Marina; Epov, Andrey; Appanna, Vasu

2003-01-01

As a first step of treatment of landfill leachates (total chemical oxygen demand [COD]: 1.43-3.81 g/L; total nitrogen: 90-162 mg/L), performance of laboratory upflow anaerobic sludge bed reactors was investigated under mesophilic (30 degrees C), submesophilic (20 degrees C), and psychrophilic (10 degrees C) conditions. Under hydraulic retention times (HRTs) of about 0.3 d, when the average organic loading rates (OLRs) were about 5 g of COD/(L.d), the total COD removal accounted for 81% (on average) with the effluent concentrations close to the anaerobic biodegradability limit (0.25 g of COD/L) for mesophilic and submesophilic regimes. The psychrophilic treatment conducted under an average HRT of 0.34 d and an average OLR of 4.22 g of COD/(L.d) showed a total COD removal of 47%, giving effluents (0.75 g of COD/L) more suitable for subsequent biologic nitrogen removal. All three anaerobic regimes used for leachate treatment were quite efficient for elimination of heavy metals (Fe, Zn, Cu, Pb, Cd) by concomitant precipitation in the form of insoluble sulfides inside the sludge bed. The application of aerobic/ anoxic biofilter as a sole polishing step for psychrophilic anaerobic effluents was acceptable for elimination of biodegradable COD and nitrogen approaching the current standards for direct discharge of treated wastewater.

Anaerobic treatment of Tequila vinasses in a CSTR-type digester.

PubMed

Méndez-Acosta, Hugo Oscar; Snell-Castro, Raúl; Alcaraz-González, Víctor; González-Alvarez, Víctor; Pelayo-Ortiz, Carlos

2010-06-01

Tequila industries in general produce great volumes of effluents with high pollutant loads, which are discharged (untreated or partially treated) into natural receivers, thus causing severe environmental problems. In this contribution, we propose an integrated system as a first step to comply with the Mexican ecological norms and stabilize the anaerobic treatment of Tequila vinasses with main design criteria: simple and easy operation, reduce operating time and associated costs (maintenance), integrated and compact design, minimal cost of set-up, start-up, monitoring and control. This system is composed of a fully instrumented and automated lab-scale CSTR-type digester, on-line measuring devices of key variables (pH, temperature, flow rates, etc.), which are used along with off-line readings of chemical oxygen demand (COD), biogas composition, alkalinity and volatile fatty acids to guarantee the operational stability of the anaerobic digestion process. The system performance was evaluated for 200 days and the experimental results show that even under the influence of load disturbances, it is possible to reduce the COD concentration to 85% in the start-up phase and up to 95% during the normal operation phase while producing a biogas with a methane composition greater than 65%. It is also shown that in order to maintain an efficient treatment, the buffering capacity (given by the alkalinity ratio, alpha = intermediate alkalinity/total alkalinity) must be closely monitored.

Impact of paper and cardboard suppression on OFMSW anaerobic digestion.

PubMed

Fonoll, X; Astals, S; Dosta, J; Mata-Alvarez, J

2016-10-01

Mechanical-biological treatment plants treat municipal solid waste to recover recyclable materials, nutrients and energy. Waste paper and cardboard (WP), the second main compound in municipal solid waste (∼30% in weight basis), is typically used for biogas generation. However, its recovery is gaining attention as it can be used to produce add-value products like bioethanol and residual derived fuel. Nevertheless, WP suppression or replacement will impact anaerobic digestion in terms of biogas production, process stability and digestate management. Two lab-scale reactors were used to assess the impact of WP in anaerobic digestion performance. A control reactor was only fed with biowaste (BioW), while a second reactor was fed with two different mixtures of BioW and WP, i.e. 85/15% and 70/30% (weight basis). Results indicate that either replacing half of the WP by BioW or removing half of the WP has little impact on the methane production. When removing half of the WP, methane production could be sustained by a larger waste biodegradability. The replacement of all WP by BioW increased the reactor methane production (∼37%), while removing all WP would have reduced the methane production about 15%. Finally, replacing WP loading rate by BioW led to a system less tolerant to instability periods and with poorer digestate quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biogas generation in anaerobic wastewater treatment under tetracycline antibiotic pressure

PubMed Central

Lu, Meiqing; Niu, Xiaojun; Liu, Wei; Zhang, Jun; Wang, Jie; Yang, Jia; Wang, Wenqi; Yang, Zhiquan

2016-01-01

The effect of tetracycline (TC) antibiotic on biogas generation in anaerobic wastewater treatment was studied. A lab-scale Anaerobic Baffled Reactor (ABR) with three compartments was used. The reactor was operated with synthetic wastewater in the absence of TC and in the presence of 250 μg/L TC for 90 days, respectively. The removal rate of TC, volatile fatty acids (VFAs), biogas compositions (hydrogen (H2), methane (CH4), carbon dioxide (CO2)), and total biogas production in each compartment were monitored in the two operational conditions. Results showed that the removal rate of TC was 14.97–67.97% in the reactor. The presence of TC had a large negative effect on CH4 and CO2 generation, but appeared to have a positive effect on H2 production and VFAs accumulation. This response indicated that the methanogenesis process was sensitive to TC presence, but the acidogenesis process was insensitive. This suggested that the presence of TC had less influence on the degradation of organic matter but had a strong influence on biogas generation. Additionally, the decrease of CH4 and CO2 generation and the increase of H2 and VFAs accumulation suggest a promising strategy to help alleviate global warming and improve resource recovery in an environmentally friendly approach. PMID:27341657

Anaerobic cultures from preserved tissues of baby mammoth

NASA Astrophysics Data System (ADS)

Pikuta, Elena V.; Fisher, Daniel; Hoover, Richard B.

2011-10-01

Microbiological analysis of several cold-preserved tissue samples from the Siberian baby mammoth known as Lyuba revealed a number of culturable bacterial strains that were grown on anaerobic media at 3 oC. Lactic acid produced by LAB (lactic acid bacteria) group, usually by members of the genera Carnobacterium and Lactosphera, appears to be a wonderful preservative that keeps other bacteria from colonizing a system. Permafrost and lactic acid preserved the body of this one month-old baby mammoth and kept it in exceptionally good condition, resulting in this mammoth being the most complete sample of the species ever recovered. The diversity of novel psychrophilic anaerobic isolates was expressed on morphological, physiological and phylogenetic levels. Here, we discuss the specifics of the isolation of new psychrophilic strains, differentiation from trivial contamination, and preliminary results for characterization of the cultures.

Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure.

PubMed

Arikan, Osman A; Mulbry, Walter; Lansing, Stephanie

2015-09-01

Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion. In temperate climates, digesters require a considerable amount of additional heat energy to maintain temperatures at these levels. In this study, the effects of lower digestion temperatures (22 and 28°C), on the methane production from dairy digesters were evaluated and compared with 35°C using duplicate replicates of field-scale (FS) digesters with a 17-day hydraulic retention time. After acclimation, the FS digesters were operated for 12weeks using solids-separated manure at an organic loading rate (OLR) of 1.4kgVSm(-3)d(-1) and then for 8weeks using separated manure amended with manure solids at an OLR of 2.6kgVSm(-3)d(-1). Methane production values of the FS digesters at 22 and 28°C were about 70% and 87%, respectively, of the values from FS digesters at 35°C. The results suggest that anaerobic digesters treating dairy manure at 28°C were nearly as efficient as digesters operated at 35°C, with 70% of total methane achievable at 22°C. These results are relevant to small farms interested in anaerobic digestion for methane reduction without heat recovery from generators or for methane recovery from covered lagoon digesters. Copyright © 2015 Elsevier Ltd. All rights reserved.

Demonstration-scale evaluation of a novel high-solids anaerobic digestion process for converting organic wastes to fuel gas and compost.

PubMed

Rivard, C J; Duff, B W; Dickow, J H; Wiles, C C; Nagle, N J; Gaddy, J L; Clausen, E C

1998-01-01

Early evaluations of the bioconversion potential for combined wastes such as tuna sludge and sorted municipal solid waste (MSW) were conducted at laboratory scale and compared conventional low-solids, stirred-tank anaerobic systems with the novel, high-solids anaerobic digester (HSAD) design. Enhanced feedstock conversion rates and yields were determined for the HSAD system. In addition, the HSAD system demonstrated superior resiliency to process failure. Utilizing relatively dry feedstocks, the HSAD system is approximately one-tenth the size of conventional low-solids systems. In addition, the HSAD system is capable of organic loading rates (OLRs) on the order of 20-25 g volatile solids per liter digester volume per d (gVS/L/d), roughly 4-5 times those of conventional systems. Current efforts involve developing a demonstration-scale (pilot-scale) HSAD system. A two-ton/d plant has been constructed in Stanton, CA and is currently in the commissioning/startup phase. The purposes of the project are to verify laboratory- and intermediate-scale process performance; test the performance of large-scale prototype mechanical systems; demonstrate the long-term reliability of the process; and generate the process and economic data required for the design, financing, and construction of full-scale commercial systems. This study presents conformational fermentation data obtained at intermediate-scale and a snapshot of the pilot-scale project.

RANS Simulation (Virtual Blade Model [VBM]) of Array of Three Coaxial Lab Scaled DOE RM1 MHK Turbine with 5D Spacing

DOE Data Explorer

Javaherchi, Teymour

2016-06-08

Attached are the .cas and .dat files along with the required User Defined Functions (UDFs) and look-up table of lift and drag coefficients for the Reynolds Averaged Navier-Stokes (RANS) simulation of three coaxially located lab-scaled DOE RM1 turbine implemented in ANSYS FLUENT CFD-package. The lab-scaled DOE RM1 is a re-design geometry, based of the full scale DOE RM1 design, producing same power output as the full scale model, while operating at matched Tip Speed Ratio values at reachable laboratory Reynolds number (see attached paper). In this case study the flow field around and in the wake of the lab-scaled DOE RM1 turbines in a coaxial array is simulated using Blade Element Model (a.k.a Virtual Blade Model) by solving RANS equations coupled with k-\\omega turbulence closure model. It should be highlighted that in this simulation the actual geometry of the rotor blade is not modeled. The effect of turbine rotating blades are modeled using the Blade Element Theory. This simulation provides an accurate estimate for the performance of each device and structure of their turbulent far wake. The results of these simulations were validated against the developed in-house experimental data. Simulations for other turbine configurations are available upon request.

Microbial characteristics in anaerobic digestion process of food waste for methane production-A review.

PubMed

Wang, Pan; Wang, Hongtao; Qiu, Yinquan; Ren, Lianhai; Jiang, Bin

2018-01-01

Food waste (FW) is rich in starch, fat, protein and cellulose. It is easy to decay and brings environmental pollution and other social problems. FW shows a high potential to produce methane by anaerobic digestion (AD) due to its high organic content. However, many inhibitors, such as accumulation of ammonia and volatile fatty acids (VFAs), usually result in inefficient performances and even process failure. Microorganisms play an important role in the process of hydrolysis, acidogenesis, acetogenesis and methanogenesis. This review provided a critical summary of microbial characteristics to obtain connects of microbial community structure with operational conditions at various states of AD, such as mesophilic and thermophilic, wet and dry, success and failure, pretreated or not, lab-scale and full-scale. This article emphasizes that it is necessary to analyze changes and mechanisms of microbial communities in unbalanced system and seek efficiency dynamic succession rules of the dominant microorganisms. Copyright © 2017. Published by Elsevier Ltd.

Sustainable green technology on wastewater treatment: The evaluation of enhanced single chambered up-flow membrane-less microbial fuel cell.

PubMed

Thung, Wei-Eng; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Ridwan, Fahmi; Oon, Yoong-Ling; Oon, Yoong-Sin; Lehl, Harvinder Kaur

2018-04-01

This study demonstrated the potential of single chamber up-flow membrane-less microbial fuel cell (UFML-MFC) in wastewater treatment and power generation. The purpose of this study was to evaluate and enhance the performance under different operational conditions which affect the chemical oxygen demand (COD) reduction and power generation, including the increase of KCl concentration (MFC1) and COD concentration (MFC2). The results showed that the increase of KCl concentration is an important factor in up-flow membrane-less MFC to enhance the ease of electron transfer from anode to cathode. The increase of COD concentration in MFC2 could led to the drop of voltage output due to the prompt of biofilm growth in MFC2 cathode which could increase the internal resistance. It also showed that the COD concentration is a vital issue in up-flow membrane-less MFC. Despite the COD reduction was up to 96%, the power output remained constrained. Copyright © 2017. Published by Elsevier B.V.

Production of polyhydroxyalkanoates (PHA) by bacterial consortium from excess sludge fermentation liquid at laboratory and pilot scales.

PubMed

Jia, Qianqian; Xiong, Huilei; Wang, Hui; Shi, Hanchang; Sheng, Xinying; Sun, Run; Chen, Guoqiang

2014-11-01

The generation of polyhydroxyalkanoates (PHA) from excess sludge fermentation liquid (SFL) was studied at lab and pilot scale. A PHA-accumulated bacterial consortium (S-150) was isolated from activated sludge using simulated SFL (S-SFL) contained high concentration volatile fatty acids (VFA) and nitrogen. The maximal PHA content accounted for 59.18% in S-SFL and dropped to 23.47% in actual SFL (L-SFL) of the dry cell weight (DCW) at lab scale. The pilot-scale integrated system comprised an anaerobic fermentation reactor (AFR), a ceramic membrane system (CMS) and a PHA production bio-reactor (PHAR). The PHA content from pilot-scale SFL (P-SFL) finally reached to 59.47% DCW with the maximal PHA yield coefficient (YP/S) of 0.17 g PHA/g COD. The results indicated that VFA-containing SFL was suitable for PHA production. The adverse impact of excess nitrogen and non-VFAs in SFL might be eliminated by pilot-scale domestication, which might resulted in community structure optimization and substrate selective ability improvement of S-150. Copyright © 2014 Elsevier Ltd. All rights reserved.

[Effect of NaOH-treatment on advanced anaerobic biogasification of Spartina alterniflora].

PubMed

Chen, Guang-Yin; Zheng, Zheng; Chang, Zhi-Zhou; Ye, Xiao-Mei

2011-08-01

In order to improve the biotransformation rate of Sparnina alterniflora, effect of NaOH-treatment on anaerobic dry-mesophilic digestion of Spartina alterniflora and feasibility of NaOH-treatment as a pretreatment of biogas residues of Spartina alterniflora for advanced anaerobic biogasification were conducted under lab-scale conditions. The results indicated that there was less improvement to biogas yield with NaOH-treatment and the cumulative biogas yield of Spartina alterniflora was 358.94 mL/g TS which was 92.42% to that of control (CK). However, the average methane content was improved slightly with 1.84% improvement. After solid-state pretreatment with 5% NaOH solution for 48 h, the biogas residue of Spartina alterniflora was used for advanced biogasification. This experiment was conducted under 35 degrees C +/- 1 degrees C with initial total solid loading of 8%. The cumulative biogas yield was 209.73 mL/g TS with 70.78% of average methane content, but the biotransformation rate was only 23.29% which was much lower than that of Spartina alterniflora. The fermentation type was propionic acid type fermentation. After two-phase fermentation treatment, cellulose content was decreased significantly while lignin and hemicellulose content were increased. The crystalinity of cellulose of biogas residue decreased after two-phase anaerobic fermentation which was consistent to result of FTIR. The comprehensive analysis of experiment indicated that biogas residue of Spartina alterniflora was still a good material for biogas production and NaOH-treatment was a good pretreatment for biogas production.

Berkeley Lab - Materials Sciences Division

Science.gov Websites

Synthesis Condensed Matter and Materials Physics Scattering and Instrumentation Science Centers Center for materials and phenomena at multiple time and length scales. Through our core programs and research centers Berkeley Lab Berkeley Lab A-Z Index Phone Book Jobs Search DOE Search MSD Go MSD - Materials

Anaerobic reactor/high rate pond combined technology for sewage treatment in the Mediterranean area.

PubMed

El Hafiane, F; El Hamouri, B

2005-01-01

Two high-rate, anaerobic/aerobic units were used to treat the sewage of the Institut Agronomique st Vétérinaire Hassan II (Morocco) campus in a 1,100 m2-plant designed for 1,500 e.p. and receiving 63 m3 per day. The anaerobic pre-treatment consisted of a two-step up-flow anaerobic reactor (TSUAR) comprising two reactors and one external settler all in series. The aerobic line, or post-treatment, consisted of a high-rate algal pond (HRAP) and one maturation pond in series. The system totalized a hydraulic retention time (HRT) of 9 days. A gravel filter (GF) was constructed behind the TSUAR to trap low-density particles. The TSUAR removed 80% of COD and 90% of SS within 48 h. Solids retention time in the reactors averaged 32 d with a specific sludge production of 0.28 g SS g(-1) COD removed. Almost 93% of the sludge evacuated from the settler was stabilized. Specific biogas production from both reactors was 0.25m3 kg(-1) COD removed. Used in this configuration, the HRAP lost its BOD removal activity and increased its nutrients and pathogens removal capabilities (tertiary treatment). Results showed that 85% of total nitrogen and 48% of total phosphorus were removed by the HRAP. Land area requirement of this combination was less than 1 m2 per capita and filtered final effluent was of excellent quality (COD, 82 mg/l; TKN, 8.3 mg/l; total P, 2.7 mg/l, faecal coliforms, 2.4 10(3)/100 ml and zero helminths eggs).

Is aceticlastic methanogen composition in full-scale anaerobic processes related to acetate utilization capacity?

PubMed

Yilmaz, Vedat; Ince-Yilmaz, Ebru; Yilmazel, Yasemin Dilsad; Duran, Metin

2014-06-01

In this study, biomass samples were obtained from six municipal and nine industrial full-scale anaerobic processes to investigate whether the aceticlastic methanogen population composition is related to acetate utilization capacity and the nature of the wastewater treated, i.e. municipal sludge or industrial wastewater. Batch serum bottle tests were used to determine the specific acetate utilization rate (AUR), and a quantitative real-time polymerase chain reaction protocol was used to enumerate the acetate-utilizing Methanosaeta and Methanosarcina populations in the biomass samples. Methanosaeta was the dominant aceticlastic methanogen in all samples, except for one industrial wastewater-treating anaerobic process. However, Methanosarcina density in industrial biomass samples was higher than the Methanosarcina density in the municipal samples. The average AUR values of municipal and industrial wastewater treatment plant biomass samples were 10.49 and 10.65 mg CH3COO(-)/log(aceticlastic methanogen gene copy).d, respectively. One-way ANOVA test and principle component analysis showed that the acetate utilization capacities and aceticlastic methanogen community composition did not show statistically significant correlation among the municipal digesters and industrial wastewater-treating processes investigated.

TREATMENT OF CHLORINATED VOLATILE ORGANIC COMPOUNDS IN UPFLOW WETLAND MESOCOSMS. (R828773C003)

EPA Science Inventory

Sorption, biodegradation and hydraulic parameters were determined in the laboratory for two candidate soil substrate mixtures for construction of an upflow treatment wetland for volatile organic compounds (VOCs) at a Superfund site. The major parent contaminants in the groundw...

Co-ensiling as a new technique for long-term storage of agro-industrial waste with low sugar content prior to anaerobic digestion.

PubMed

Hillion, Marie-Lou; Moscoviz, Roman; Trably, Eric; Leblanc, Yoann; Bernet, Nicolas; Torrijos, Michel; Escudié, Renaud

2018-01-01

Biodegradable wastes produced seasonally need an upstream storage, because of the requirement for a constant feeding of anaerobic digesters. In the present article, the potential of co-ensiling biodegradable agro-industrial waste (sugar beet leaves) and lignocellulosic agricultural residue (wheat straw) to obtain a mixture with low soluble sugar content was evaluated for long-term storage prior to anaerobic digestion. The aim is to store agro-industrial waste while pretreating lignocellulosic biomass. The dynamics of co-ensiling was evaluated in vacuum-packed bags at lab-scale during 180 days. Characterization of the reaction by-products and microbial communities showed a succession of metabolic pathways. Even though the low initial sugars content was not sufficient to lower the pH under 4.5 and avoid undesirable fermentations, the methane potential was not substantially impacted all along the experiment. No lignocellulosic damages were observed during the silage process. Overall, it was shown that co-ensiling was effective to store highly fermentable fresh waste evenly with low sugar content and offers new promising possibilities for constant long-term supply of industrial anaerobic digesters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Behaviour of a full-scale expanded bed reactor with overlaid anaerobic and aerobic zones for domestic wastewater treatment.

PubMed

Mendonça, N M; Siman, R R; Niciura, C L; Campos, J R

2006-01-01

This paper presents the behaviour of a full-scale expanded bed reactor (160 m3) with overlaid anaerobic and aerobic zones used for municipal wastewater treatment. The research was carried out in two experimental steps: anaerobic and anaerobic-aerobic conditions, and the experimental results presented in this paper refer to four months of reactor operation. In the anaerobic condition, after inoculation and 60 days of operation, the reactor treating 3.40 kg CODm(-3)d(-1) for thetaH of 2.69 h, reached mean removal efficiencies of 76% for BOD, 72% for COD, and 80% for TSS, when the effluent presented mean values of 225 mg.L(-1) of COD, 98 mg.L(-1) of BOD and 35 mg.L(-1) of TSS. Under these conditions, for nitrogen loading of 0.27 kgN.m(-3)d(-1), the reactor generated an effluent with mean N-org. of 8 mg.L(-1) and N-ammon. of 37 mg.L(-1), demonstrating high potential of ammonification. For the anaerobic-aerobic condition (118th day) the system was operated with thetaH of 5.38 h presented mean removal efficiencies of 84% for BOD, 79% for COD, 76% for TSS, and 30% for TKN. The reactor's operation time was less than two months, which was not long enough to reach nitrification. Regarding the obtained results, this research confirmed that this reactor is configured as a flexible and adequate alternative for the treatment of sewage, requiring relatively small area and only thetaH of 10 h that can be adjusted to the local circumstances.

Substrate Type and Free Ammonia Determine Bacterial Community Structure in Full-Scale Mesophilic Anaerobic Digesters Treating Cattle or Swine Manure

PubMed Central

Li, Jiabao; Rui, Junpeng; Yao, Minjie; Zhang, Shiheng; Yan, Xuefeng; Wang, Yuanpeng; Yan, Zhiying; Li, Xiangzhen

2015-01-01

The microbial-mediated anaerobic digestion (AD) process represents an efficient biological process for the treatment of organic waste along with biogas harvest. Currently, the key factors structuring bacterial communities and the potential core and unique bacterial populations in manure anaerobic digesters are not completely elucidated yet. In this study, we collected sludge samples from 20 full-scale anaerobic digesters treating cattle or swine manure, and investigated the variations of bacterial community compositions using high-throughput 16S rRNA amplicon sequencing. Clustering and correlation analysis suggested that substrate type and free ammonia (FA) play key roles in determining the bacterial community structure. The COD: NH4+-N (C:N) ratio of substrate and FA were the most important available operational parameters correlating to the bacterial communities in cattle and swine manure digesters, respectively. The bacterial populations in all of the digesters were dominated by phylum Firmicutes, followed by Bacteroidetes, Proteobacteria and Chloroflexi. Increased FA content selected Firmicutes, suggesting that they probably play more important roles under high FA content. Syntrophic metabolism by Proteobacteria, Chloroflexi, Synergistetes and Planctomycetes are likely inhibited when FA content is high. Despite the different manure substrates, operational conditions and geographical locations of digesters, core bacterial communities were identified. The core communities were best characterized by phylum Firmicutes, wherein Clostridium predominated overwhelmingly. Substrate-unique and abundant communities may reflect the properties of manure substrate and operational conditions. These findings extend our current understanding of the bacterial assembly in full-scale manure anaerobic digesters. PMID:26648921

Deterministic mechanisms define the long-term anaerobic digestion microbiome and its functionality regardless of the initial microbial community.

PubMed

Peces, M; Astals, S; Jensen, P D; Clarke, W P

2018-05-17

The impact of the starting inoculum on long-term anaerobic digestion performance, process functionality and microbial community composition remains unclear. To understand the impact of starting inoculum, active microbial communities from four different full-scale anaerobic digesters were each used to inoculate four continuous lab-scale anaerobic digesters, which were operated identically for 295 days. Digesters were operated at 15 days solid retention time, an organic loading rate of 1 g COD L r -1 d -1 (75:25 - cellulose:casein) and 37 °C. Results showed that long-term process performance, metabolic rates (hydrolytic, acetogenic, and methanogenic) and microbial community are independent of the inoculum source. Digesters process performance converged after 80 days, while metabolic rates and microbial communities converged after 120-145 days. The convergence of the different microbial communities towards a core-community proves that the deterministic factors (process operational conditions) were a stronger driver than the initial microbial community composition. Indeed, the core-community represented 72% of the relative abundance among the four digesters. Moreover, a number of positive correlations were observed between higher metabolic rates and the relative abundance of specific microbial groups. These correlations showed that both substrate consumers and suppliers trigger higher metabolic rates, expanding the knowledge of the nexus between microorganisms and functionality. Overall, these results support that deterministic factors control microbial communities in bioreactors independently of the inoculum source. Hence, it seems plausible that a desired microbial composition and functionality can be achieved by tuning process operational conditions. Copyright © 2018. Published by Elsevier Ltd.

[Study on the start-up of anaerobic ammonium oxidation process in biological activated carbon reactor].

PubMed

Lai, Wei-Yi; Zhou, Wei-Li; He, Sheng-Bing

2013-08-01

In order to shorten the start-up time of anaerobic ammonium oxidation (ANAMMOX) reactor, biological activated cabon reactor was applied. Three lab scale UASB reactors were seeded with anaerobic sludge, fed with synthetic wastewater containing ammonia and nitrite, and supplemented with granular activated carbon on day 0, 33 and 56, respectively. The nitrogen removal performance of the first reactor, into which GAC was added on day 0, showed no significant improvement in 90 days. After being suspended for about one month, the secondary start-up of this reactor succeeded in another 33 days (totally 123 days). 49 d and 85 d were taken for the other two reactors started up by the addition of GAC on day 33 and 56, respectively. After the reactors were started up, the average removal rates of total nitrogen were 89.8%, 86.7% and 86.7%, respectively. The start-up process could be divided into four stages, namely, the bacterial autolysis phase, the lag phase, the improve phase and the stationary phase, and the best time for adding GAC carrier was right after the start of the lag phase.

Fact-finding survey of actual garbage discharged from dormitory and its biological anaerobic-aerobic treatment.

PubMed

Imai, T; Ukita, M; Sekine, M; Fukagawa, M; Nakanishi, H

2000-01-01

The objective of this study is to find a possibility of complete treatment of garbage and resource recovery (production of methane from available utility of carbon resource in garbage) by biological treatment process. As the first step, a fact-finding survey of actual garbage discharged from the dormitory of the Ube National College of Technology (equivalent to 300 population) was carried out. Second, the combined biological anaerobic-aerobic treatment, i.e. combination of upflow anaerobic sludge blanket (UASB) process and aerobic membrane bioreactor (AMB) process, was applied to the garbage treatment. The applicability and efficiency of this system were investigated in this study. The survey results showed that the composition and quantity of garbage from a student dormitory changed slightly during a week due to the change of the menu, however, they remained almost unchanged during the entire experimental period. The experimental results showed high biodegradability of the garbage, and demonstrated its suitability for methane production. The soluble nitrogen removal was high: over 97%. No excess sludge was wasted from the system. A high treatment efficiency of simultaneous organic carbon and nitrogen was obtained. The possibility of complete treatment of garbage with this process has been positively demonstrated by this study.

Scaling behavior in exclusive meson photoproduction from Jefferson Lab at large momentum transfers

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

Dey, Biplab

2014-07-01

With the availability of new high-statistics and wide-angle measurements for several exclusive non-πN meson photoproduction channels from Jefferson Lab, we examine the fundamental scaling law of 90° scattering in QCD that was originally derived in the high-energy perturbative limit. The data show scaling to be prominently visible even in the medium-energy domain of 2.5 GeV ≲√s≲2.84 GeV, where √s is the center-of-mass energy. While constituent quark exchange suffices for pseudoscalar mesons, additional gluon exchanges from higher Fock states of the hadronic wave functions appear be needed for vector-meson production. Finally, the case of the Φ(1020), where two-gluon exchanges are knownmore » to dominate, is especially illuminating.« less

Advanced LabVIEW Labs

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

Jones, Eric D.

1999-06-17

In the world of computer-based data acquisition and control, the graphical interface program LabVIEW from National Instruments is so ubiquitous that in many ways it has almost become the laboratory standard. To date, there have been approximately fifteen books concerning LabVIEW, but Professor Essick's treatise takes on a completely different tack than all of the previous discussions. In the more standard treatments of the ways and wherefores of LabVIEW such as LabVIEW Graphical Programming: Practical Applications in Instrumentation and Control by Gary W. Johnson (McGraw Hill, NY 1997), the emphasis has been instructing the reader how to program LabVIEW tomore » create a Virtual Instrument (VI) on the computer for interfacing to a particular instruments. LabVIEW is written in G a graphical programming language developed by National Instruments. In the past the emphasis has been on training the experimenter to learn G . Without going into details here, G incorporates the usual loops, arithmetic expressions, etc., found in many programming languages, but in an icon (graphical) environment. The net result being that LabVIEW contains all of the standard methods needed for interfacing to instruments, data acquisition, data analysis, graphics, and also methodology to incorporate programs written in other languages into LabVIEW. Historically, according to Professor Essick, he developed a series of experiments for an upper division laboratory course for computer-based instrumentation. His observation was that while many students had the necessary background in computer programming languages, there were students who had virtually no concept about writing a computer program let alone a computer- based interfacing program. Thus the beginnings of a concept for not only teaching computer- based instrumentation techniques, but aiso a method for the beginner to experience writing a com- puter program. Professor Essick saw LabVIEW as the perfect environment in which to teach

Advanced LabVIEW Labs

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

Jones, Eric D.

1999-06-17

In the world of computer-based data acquisition and control, the graphical interface program LabVIEW from National Instruments is so ubiquitous that in many ways it has almost become the laboratory standard. To date, there have been approximately fifteen books concerning LabVIEW, but Professor Essick's treatise takes on a completely different tack than all of the previous discussions. In the more standard treatments of the ways and wherefores of LabVIEW such as LabVIEW Graphical Programming: Practical Applications in Instrumentation and Control by Gary W. Johnson (McGraw Hill, NY 1997), the emphasis has been instructing the reader how to program LabVIEW tomore » create a Virtual Instrument (VI) on the computer for interfacing to a particular instruments. LabVIEW is written in "G" a graphical programming language developed by National Instruments. In the past the emphasis has been on training the experimenter to learn "G". Without going into details here, "G" incorporates the usual loops, arithmetic expressions, etc., found in many programming languages, but in an icon (graphical) environment. The net result being that LabVIEW contains all of the standard methods needed for interfacing to instruments, data acquisition, data analysis, graphics, and also methodology to incorporate programs written in other languages into LabVIEW. Historically, according to Professor Essick, he developed a series of experiments for an upper division laboratory course for computer-based instrumentation. His observation was that while many students had the necessary background in computer programming languages, there were students who had virtually no concept about writing a computer program let alone a computer- based interfacing program. Thus the beginnings of a concept for not only teaching computer- based instrumentation techniques, but aiso a method for the beginner to experience writing a com- puter program. Professor Essick saw LabVIEW as the "perfect environment in which to

Energy performance evaluation of ultrasonic pretreatment of organic solid waste in a pilot-scale digester.

PubMed

Rasapoor, Mazdak; Adl, Mehrdad; Baroutian, Saeid; Iranshahi, Zeynab; Pazouki, Mohammad

2018-04-30

It has been proven that ultrasonic pretreatment (UP) has positive effect on biogas generation from previous lab-scale studies. However, that is not always the case in larger scale processes. The purpose of this study was to evaluate the effectiveness of UP to biogas generation in terms of anaerobic digestion process and energy efficiency. Parameters including total solids (TS) and ultrasonic treatment operational parameters of organic solid waste (OSW) resulted from our past lab scale UP studies were applied in this study. OSW with 6-10% TS was treated using a lab-scale ultrasonic processor using various power densities (0.2-0.6 W/mL) at different time periods up to 30 min. Results of lab scale confirmed that OSW with 6% TS sonicated with 0.2 W/mL power density in 30 min gave the best outcome for the pilot scale experiment. To simulate the condition of an actual scale, in addition to energy analysis, two different organic loading rates (OLR), namely 500 and 1500 gVS/m 3 day were examined. The pilot digester was fed with OSW with or without the pretreatment based on the aforementioned specifications. The results showed that UP effectively improves biogas generation in terms of quantity and quality (CH 4 /CO 2 ). Furthermore, it decreases the time to reach the maximum cumulative biogas volume comparing to the untreated feed. The key achievement of this research has confirmed that although the relative increase in the energy gain by the influence of UP was more remarkable under the 500 gVS/m 3 day OLR, energy analysis showed a better energy gain and energy benefit as well as jumping in biogas yield up to 80% for UP treated OSW under 1500 gVS/m 3 day OLR. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of pore-scale hydrate phase equilibria in sediments using lab-on-a-chip technology.

PubMed

Almenningen, Stian; Flatlandsmo, Josef; Kovscek, Anthony R; Ersland, Geir; Fernø, Martin A

2017-11-21

We present an experimental protocol for fast determination of hydrate stability in porous media for a range of pressure and temperature (P, T) conditions. Using a lab-on-a-chip approach, we gain direct optical access to dynamic pore-scale hydrate formation and dissociation events to study the hydrate phase equilibria in sediments. Optical pore-scale observations of phase behavior reproduce the theoretical hydrate stability line with methane gas and distilled water, and demonstrate the accuracy of the new method. The procedure is applicable for any kind of hydrate transitions in sediments, and may be used to map gas hydrate stability zones in nature.

New insights into the enhanced performance of high solid anaerobic digestion with dewatered sludge by thermal hydrolysis: Organic matter degradation and methanogenic pathways.

PubMed

Chen, Sisi; Li, Ning; Dong, Bin; Zhao, Wentao; Dai, Lingling; Dai, Xiaohu

2018-01-15

Two lab-scale high solid anaerobic digesters fed with untreated sludge (R1) and thermally hydrolyzed sludge (R2) were operated to investigate the influence of thermal hydrolysis pretreatment (THP) on the degradation of individual macromolecular organic components (MOCs), as well as the functional and metabolic responses of microbes during anaerobic digestion (AD). The degradation of MOCs was improved by THP at different rates, in which improved degradation of proteins (by 49.0%) and hemicelluloses (by 25.0%) were the main factors contributing to the increase in volatile solids (VS) reduction. However, no enhancement of final degradation extent of MOCs was observed. With a more densified microbial population, R2 was also enriched in genes involved in amino acid and carbohydrate metabolism, reflected in the enhanced degradation of proteins and carbohydrates. After THP, the methanogenic pathway shifted from strict acetoclastic methanogenesis to acetoclastic/hydrogenotrophic methanogenesis, consistent with the enhanced methane production and the increase of methane content. Copyright © 2017 Elsevier B.V. All rights reserved.

Determinant impact of waste collection and composition on anaerobic digestion performance: industrial results.

PubMed

Saint-Joly, C; Desbois, S; Lotti, J P

2000-01-01

The performance of the anaerobic digestion process depends deeply on the quality of the waste to be treated. This has been already demonstrated at the lab-scale. The objective of this study is to confirm this result at the industrial scale, with very long representative period and with the same process, the Valorga process. According to the waste quality and the collection type and even with the same conditions of fermentation, the biogas yield can vary by a factor of 1.5 when it is expressed (under normal conditions of pressure and temperature) in m3 biogas/t fresh waste, and by a factor of 2 when it is expressed in m3 CH4/t volatile solids. So, the biogas performance does not characterise a process since it is deeply governed by waste composition. This biogas productivity becomes a pertinent parameter only with consistent and relevant hypothesis and/or analytical results on the waste composition which depends on the collection procedure, the site characteristics and the season.

Removal of Total Coliforms, Thermotolerant Coliforms, and Helminth Eggs in Swine Production Wastewater Treated in Anaerobic and Aerobic Reactors

PubMed Central

Zacarias Sylvestre, Silvia Helena; Lux Hoppe, Estevam Guilherme; de Oliveira, Roberto Alves

2014-01-01

The present work evaluated the performance of two treatment systems in reducing indicators of biological contamination in swine production wastewater. System I consisted of two upflow anaerobic sludge blanket (UASB) reactors, with 510 and 209 L in volume, being serially arranged. System II consisted of a UASB reactor, anaerobic filter, trickling filter, and decanter, being also organized in series, with volumes of 300, 190, 250, and 150 L, respectively. Hydraulic retention times (HRT) applied in the first UASB reactors were 40, 30, 20, and 11 h in systems I and II. The average removal efficiencies of total and thermotolerant coliforms in system I were 92.92% to 99.50% and 94.29% to 99.56%, respectively, and increased in system II to 99.45% to 99.91% and 99.52% to 99.93%, respectively. Average removal rates of helminth eggs in system I were 96.44% to 99.11%, reaching 100% as in system II. In reactor sludge, the counts of total and thermotolerant coliforms ranged between 105 and 109 MPN (100 mL)−1, while helminth eggs ranged from 0.86 to 9.27 eggs g−1 TS. PMID:24812560

Treatment of a chocolate industry wastewater in a pilot-scale low-temperature UASB reactor operated at short hydraulic and sludge retention time.

PubMed

Esparza-Soto, M; Arzate-Archundia, O; Solís-Morelos, C; Fall, C

2013-01-01

The aim of this work was to evaluate the performance of a 244-L pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of chocolate-processing industry wastewater under low-temperature conditions (18 ± 0.6 °C) for approximately 250 d. The applied organic loading rate (OLR) was varied between 4 and 7 kg/m(3)/d by varying the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (6.4 ± 0.3 h). The CODsol removal efficiency was low (59-78%). The measured biogas production increased from 240 ± 54 to 431 ± 61 L/d during the experiments. A significant linear correlation between the measured biogas production and removed OLR indicated that 81.69 L of biogas were produced per kg/m(3) of CODsol removed. Low average reactor volatile suspended solids (VSS) (2,700-4,800 mg/L) and high effluent VSS (177-313 mg/L) were derived in a short sludge retention time (SRT) (4.9 d). The calculated SRT was shorter than those reported in the literature, but did not affect the reactor's performance. Average sludge yield was 0.20 kg-VSS/kg-CODsol. The low-temperature anaerobic treatment was a good option for the pre-treatment of chocolate-processing industry wastewater.

Elimination patterns of worldwide used sulfonamides and tetracyclines during anaerobic fermentation.

PubMed

Spielmeyer, Astrid; Breier, Bettina; Groißmeier, Kathrin; Hamscher, Gerd

2015-10-01

Antibiotics such as sulfonamides and tetracyclines are frequently used in veterinary medicine. Due to incomplete absorption in the animal gut and/or unmetabolized excretion, the substances can enter the environment by using manure as soil fertilizer. The anaerobic fermentation process of biogas plants is discussed as potential sink for antibiotic compounds. However, negative impacts of antibiotics on the fermentation process are suspected. The elimination of sulfadiazine, sulfamethazine, tetracycline and chlortetracycline in semi-continuous lab-scale fermenters was investigated. Both biogas production and methane yield were not negatively affected by concentrations up to 38 mg per kg for sulfonamides and 7 mg per kg for tetracyclines. All substances were partly eliminated with elimination rates between 14% and 89%. Both matrix and structure of the target molecule influenced the elimination rate. Chlortetracycline was mainly transformed into iso-chlortetracycline. In all other cases, the elimination pathways remained undiscovered; however, sorption processes seem to have a negligible impact. Copyright © 2015 Elsevier Ltd. All rights reserved.

First-order kinetics of landfill leachate treatment in a pilot-scale anaerobic sequence batch biofilm reactor.

PubMed

Contrera, Ronan Cleber; da Cruz Silva, Katia Cristina; Morita, Dione Mari; Domingues Rodrigues, José Alberto; Zaiat, Marcelo; Schalch, Valdir

2014-12-01

This paper reports the kinetics evaluation of landfill leachate anaerobic treatment in a pilot-scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR). The experiment was carried out at room temperature (23.8 ± 2.1 °C) in the landfill area in São Carlos-SP, Brazil. Biomass from the bottom of a local landfill leachate stabilization pond was used as inoculum. After acclimated and utilizing leachate directly from the landfill, the AnSBBR presented efficiency over 70%, in terms of COD removal, with influent COD ranging from 4825 mg L(-1) to 12,330 mg L(-1). To evaluate the kinetics of landfill leachate treatment, temporal profiles of CODFilt. concentration were performed and a first-order kinetics model was adjusted for substrate consumption, obtaining an average k1 = 4.40 × 10(-5) L mgTVS(-1) d(-1), corrected to 25 °C. Considering the temperature variations, a temperature-activity coefficient θ = 1.07 was obtained. Statistical "Randomness" and "F" tests were used to successfully validate the model considered. Thus, the results demonstrate that the first-order kinetic model is adequate to model the anaerobic treatment of the landfill leachate in the AnSBBR. Copyright © 2014 Elsevier Ltd. All rights reserved.

Treatment of radioactive liquid effluents by reverse osmosis membranes: From lab-scale to pilot-scale.

PubMed

Combernoux, Nicolas; Schrive, Luc; Labed, Véronique; Wyart, Yvan; Carretier, Emilie; Moulin, Philippe

2017-10-15

The recent use of the reverse osmosis (RO) process at the damaged Fukushima-Daiichi nuclear power plant generated a growing interest in the application of this process for decontamination purposes. This study focused on the development of a robust RO process for decontamination of two kinds of liquid effluents: a contaminated groundwater after a nuclear disaster and a contaminated seawater during a nuclear accident. The SW30 HR membrane was selected among other in this study due to higher retentions (96% for Cs and 98% for Sr) in a true groundwater. Significant fouling and scaling phenomenon, attributed to calcium and strontium precipitation, were evidenced in this work: this underscored the importance of the lab scale experiment in the process. Validation of the separation performances on trace radionuclides concentration was performed with similar retention around 96% between surrogates Cs (inactive) and 137 Cs (radioactive). The scale up to a 2.6 m 2 spiral wound membrane led to equivalent retentions (around 96% for Cs and 99% for Sr) but lower flux values: this underlined that the hydrodynamic parameters (flowrate/cross-flow velocity) should be optimized. This methodology was also applied on the reconstituted seawater effluent: retentions were slightly lower than for the groundwater and the same hydrodynamic effects were observed on the pilot scale. Then, ageing of the membrane through irradiation experiments were performed. Results showed that the membrane active layer composition influenced the membrane resistance towards γ irradiation: the SW30 HR membrane performances (retention and permeability) were better than the Osmonics SE at 1 MGy. Finally, to supplement the scale up approach, the irradiation of a spiral wound membrane revealed a limited effect on the permeability and retention. This indicated that irradiation conditions need to be controlled for a further development of the process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transport of pesticides and artificial tracers in vertical-flow lab-scale wetlands

NASA Astrophysics Data System (ADS)

Durst, Romy; Imfeld, Gwenaël.; Lange, Jens

2013-01-01

Wetland systems can be hydrologically connected to a shallow aquifer and intercept upward flow of pesticide-contaminated water during groundwater discharge. However, pesticide transport and attenuation through wetland sediments (WSs) intercepting contaminated water is rarely evaluated quantitatively. The use of artificial tracers to evaluate pesticide transport and associated risks is a fairly new approach that requires evaluation and validation. Here we evaluate during 84 days the transport of two pesticides (i.e., isoproturon (IPU) and metalaxyl (MTX)) and three tracers (i.e., bromide (Br), uranine (UR), and sulforhodamine B (SRB)) in upward vertical-flow vegetated and nonvegetated lab-scale wetlands. The lab-scale wetlands were filled with outdoor WSs and were continuously supplied with tracers and the pesticide-contaminated water. The transport of IPU and UR was characterized by high solute recovery (approximately 80%) and low retardation compared to Br. The detection of desmethylisoproturon in the wetlands indicated IPU degradation. SRB showed larger retardation (>3) and lower recovery (approximately 60%) compared to Br, indicating that sorption controlled SRB transport. MTX was moderately retarded (approximately 1.5), and its load attenuation in the wetland reached 40%. In the vegetated wetland, preferential flow along the roots decreased interactions between solutes and sediments, resulting in larger pesticide and tracer recovery. Our results show that UR and IPU have similar transport characteristics under the tested subsurface-flow conditions, whereas SRB may serve as a proxy for less mobile and more persistent pesticides. Since UR and SRB are not significantly affected by degradation, their use as proxies for fast degrading pollutants may be limited. We anticipate our results to be a starting point for considering artificial tracers for investigating pesticide transport in environments at groundwater/surface-water interfaces.

Engineering and Two-Stage Evolution of a Lignocellulosic Hydrolysate-Tolerant Saccharomyces cerevisiae Strain for Anaerobic Fermentation of Xylose from AFEX Pretreated Corn Stover

PubMed Central

Parreiras, Lucas S.; Breuer, Rebecca J.; Avanasi Narasimhan, Ragothaman; Higbee, Alan J.; La Reau, Alex; Tremaine, Mary; Qin, Li; Willis, Laura B.; Bice, Benjamin D.; Bonfert, Brandi L.; Pinhancos, Rebeca C.; Balloon, Allison J.; Uppugundla, Nirmal; Liu, Tongjun; Li, Chenlin; Tanjore, Deepti; Ong, Irene M.; Li, Haibo; Pohlmann, Edward L.; Serate, Jose; Withers, Sydnor T.; Simmons, Blake A.; Hodge, David B.; Westphall, Michael S.; Coon, Joshua J.; Dale, Bruce E.; Balan, Venkatesh; Keating, David H.; Zhang, Yaoping; Landick, Robert; Gasch, Audrey P.; Sato, Trey K.

2014-01-01

The inability of the yeast Saccharomyces cerevisiae to ferment xylose effectively under anaerobic conditions is a major barrier to economical production of lignocellulosic biofuels. Although genetic approaches have enabled engineering of S. cerevisiae to convert xylose efficiently into ethanol in defined lab medium, few strains are able to ferment xylose from lignocellulosic hydrolysates in the absence of oxygen. This limited xylose conversion is believed to result from small molecules generated during biomass pretreatment and hydrolysis, which induce cellular stress and impair metabolism. Here, we describe the development of a xylose-fermenting S. cerevisiae strain with tolerance to a range of pretreated and hydrolyzed lignocellulose, including Ammonia Fiber Expansion (AFEX)-pretreated corn stover hydrolysate (ACSH). We genetically engineered a hydrolysate-resistant yeast strain with bacterial xylose isomerase and then applied two separate stages of aerobic and anaerobic directed evolution. The emergent S. cerevisiae strain rapidly converted xylose from lab medium and ACSH to ethanol under strict anaerobic conditions. Metabolomic, genetic and biochemical analyses suggested that a missense mutation in GRE3, which was acquired during the anaerobic evolution, contributed toward improved xylose conversion by reducing intracellular production of xylitol, an inhibitor of xylose isomerase. These results validate our combinatorial approach, which utilized phenotypic strain selection, rational engineering and directed evolution for the generation of a robust S. cerevisiae strain with the ability to ferment xylose anaerobically from ACSH. PMID:25222864

Reflections on Three Corporate Research Labs: Bell Labs, HP Labs, Agilent Labs

NASA Astrophysics Data System (ADS)

Hollenhorst, James

2008-03-01

This will be a personal reflection on corporate life and physics-based research in three industrial research labs over three decades, Bell Labs during the 1980's, HP Labs during the 1990's, and Agilent Labs during the 2000's. These were times of great change in all three companies. I'll point out some of the similarities and differences in corporate cultures and how this impacted the research and development activities. Along the way I'll mention some of the great products that resulted from physics-based R&D.

Performance assessment and calibration of a profiling lab-scale acoustic Doppler velocimeter for application over mixed sand-gravel beds

USDA-ARS?s Scientific Manuscript database

Acoustic Doppler velocimetry has made high-resolution turbulence measurements in sediment-laden flows possible. Recent developments have resulted in a commercially available lab-scale acoustic Doppler profiling device, a Nortek Vectrino II, that allows for three-dimensional velocity data to be colle...

The effect of enzymatic pre-hydrolysis of dairy wastewater on the granular and immobilized microbial community in anaerobic bioreactors.

PubMed

Cammarota, Magali C; Rosa, Daniela R; Duarte, Iolanda C S; Saavedra, Nora K; Varesche, Maria B A; Zaiat, Marcelo; Freire, Denise M G

2013-01-01

The effect of a lipase-rich enzyme preparation produced by the fungus Penicillium sp. on solid-state fermentation was evaluated in two anaerobic bioreactors (up-flow anaerobic sludge blanket (UASB) and horizontal-flow anaerobic immobilized biomass (HAIB)) treating dairy wastewater with 1200 mg oil and grease/L. The oil and grease hydrolysis step was carried out with 0.1% (w/v) of the solid enzymatic preparation at 30 degrees C for 24 h. This resulted in a final concentration of free acids eight times higher than the initial value. The bioreactors operated at 30 degrees C with hydraulic retention times of 12 h (HAIB) and 20 h (UASB) for a period of 430 days, and had high chemical oxygen demand (COD) removal efficiencies (around 90%) when fed with pre-hydrolyzed wastewater. There was, however, an increase in the effluent oil and grease concentration (from values as low as 17 mg/L to values above 150 mg/L in the UASB bioreactor, and from 38-242 mg/L in the HAIB bioreactor), and oil and grease accumulation in the biomass throughout the operational period (the oil and grease content reached 1.7 times that found in the inoculum of the UASB bioreactor). The HAIB bioreactor gave better results because the support for biomass immobilization acted as a filter, retaining oil and grease at the entry of the bioreactor. The molecular analysis of the Bacteria and Archaea domains revealed significant differences in the microbial profiles in experiments conducted with and without the pre-hydrolysis step. The differences observed in the overall parameters could be related to the microbial diversity of the anaerobic sludge.

Low-altitude ion heating with downflowing and upflowing ions

NASA Astrophysics Data System (ADS)

Shen, Y.; Knudsen, D. J.; Burchill, J. K.; Howarth, A. D.; Yau, A. W.; James, G.; Miles, D.; Cogger, L. L.; Perry, G. W.

2017-12-01

Mechanisms that energize ions at the initial stage of ion upflow are still not well understood. We statistically investigate ionospheric ion energization and field-aligned motion at very low altitudes (330-730 km) using simultaneous plasma, magnetic field, wave electric field and optical data from the e-POP satellite. The high-time-resolution (10 ms) dataset enables us to study the micro-structures of ion heating and field-aligned ion motion. The ion temperature and field-aligned bulk flow velocity are derived from 2-D ion distribution functions measured by the SEI instrument. From March 2015 to March 2016, we've found 17 orbits (in total 24 ion heating periods) with clear ion heating signatures passing across the dayside cleft or the nightside auroral regions. Most of these events have consistent ion heating and flow velocity characteristics observed from both the SEI and IRM instruments. The perpendicular ion temperature goes up to 4.5 eV within a 2 km-wide region in some cases, in which the Radio Receiver Instrument (RRI) sees broadband extremely low frequency (BBELF) waves, demonstrating significant wave-ion heating down to as low as 350 km. The e-POP Fast Auroral Imager (FAI) and Magnetic Field (MGF) instruments show that many events are associated with active aurora and are within downward current regions. Contrary to what would be expected from mirror-force acceleration of heated ions, the majority of these heating events (17 out of 24) are associated with the core ion downflow rather than upflow. These statistical results provide us with new sights into ion heating and field-aligned flow processes at very low altitudes.

Thermal hydrolysis integration in the anaerobic digestion process of different solid wastes: energy and economic feasibility study.

PubMed

Cano, R; Nielfa, A; Fdz-Polanco, M

2014-09-01

An economic assessment of thermal hydrolysis as a pretreatment to anaerobic digestion has been achieved to evaluate its implementation in full-scale plants. Six different solid wastes have been studied, among them municipal solid waste (MSW). Thermal hydrolysis has been tested with batch lab-scale tests, from which an energy and economic assessment of three scenarios is performed: with and without energy integration (recovering heat to produce steam in a cogeneration plant), finally including the digestate management costs. Thermal hydrolysis has lead to an increase of the methane productions (up to 50%) and kinetics parameters (even double). The study has determined that a proper energy integration design could lead to important economic savings (5 €/t) and thermal hydrolysis can enhance up to 40% the incomes of the digestion plant, even doubling them when digestate management costs are considered. In a full-scale MSW treatment plant (30,000 t/year), thermal hydrolysis would provide almost 0.5 M€/year net benefits. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anaerobic biorefinery: Current status, challenges, and opportunities.

PubMed

Sawatdeenarunat, Chayanon; Nguyen, Duc; Surendra, K C; Shrestha, Shilva; Rajendran, Karthik; Oechsner, Hans; Xie, Li; Khanal, Samir Kumar

2016-09-01

Anaerobic digestion (AD) has been in use for many decades. To date, it has been primarily aimed at treating organic wastes, mainly manures and wastewater sludge, and industrial wastewaters. However, with the current advancements, a more open mind is required to look beyond these somewhat restricted original applications of AD. Biorefineries are such concepts, where multiple products including chemicals, fuels, polymers etc. are produced from organic feedstocks. The anaerobic biorefinery concept is now gaining increased attention, utilizing AD as the final disposal step. This review aims at evaluating the potential significance of anaerobic biorefineries, including types of feedstocks, uses for the produced energy, as well as sustainable applications of the generated residual digestate. A comprehensive analysis of various types of anaerobic biorefineries has been developed, including both large-scale and household level applications. Finally, future directives are highlighted showing how anaerobic biorefinery concept could impact the bioeconomy in the near future. Copyright © 2016 Elsevier Ltd. All rights reserved.

Prediction of anaerobic biodegradability and bioaccessibility of municipal sludge by coupling sequential extractions with fluorescence spectroscopy: towards ADM1 variables characterization.

PubMed

Jimenez, Julie; Gonidec, Estelle; Cacho Rivero, Jesús Andrés; Latrille, Eric; Vedrenne, Fabien; Steyer, Jean-Philippe

2014-03-01

Advanced dynamic anaerobic digestion models, such as ADM1, require both detailed organic matter characterisation and intimate knowledge of the involved metabolic pathways. In the current study, a methodology for municipal sludge characterization is investigated to describe two key parameters: biodegradability and bioaccessibility of organic matter. The methodology is based on coupling sequential chemical extractions with 3D fluorescence spectroscopy. The use of increasingly strong solvents reveals different levels of organic matter accessibility and the spectroscopy measurement leads to a detailed characterisation of the organic matter. The results obtained from testing 52 municipal sludge samples (primary, secondary, digested and thermally treated) showed a successful correlation with sludge biodegradability and bioaccessibility. The two parameters, traditionally obtained through the biochemical methane potential (BMP) lab tests, are now obtain in only 5 days compared to the 30-60 days usually required. Experimental data, obtained from two different laboratory scale reactors, were used to validate the ADM1 model. The proposed approach showed a strong application potential for reactor design and advanced control of anaerobic digestion processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

Aeration of the teuftal landfill: Field scale concept and lab scale simulation.

PubMed

Ritzkowski, Marco; Walker, Beat; Kuchta, Kerstin; Raga, Roberto; Stegmann, Rainer

2016-09-01

Long lasting post-closure care (PCC) is often the major financial burden for operators of municipal solid waste (MSW) landfills. Beside costs for the installation and maintenance of technical equipment and barriers, in particular long term treatment of leachate and landfill gas has to be paid from capital surplus. Estimations based on laboratory experiments project time periods of many decades until leachate quality allows for direct discharge (i.e. no need for further purification). Projections based on leachate samples derived from the last 37years for 35 German landfills confirm these assumption. Moreover, the data illustrate that in particular ammonium nitrogen concentrations are likely to fall below limit values only after a period of 300years. In order to avoid long lasting PCC the operator of Teuftal landfill, located in the Swiss canton Bern, decided to biologically stabilize the landfill by means of a combined in situ aeration and moisturization approach. In December 2014 the aeration started at a landfill section containing approximately 30% of the total landfill volume. From summer 2016 onwards the remaining part of the landfill will be aerated. Landfill aeration through horizontal gas and leachate drains is carried out for the first time in field scale in Europe. The technical concept is described in the paper. Parallel to field scale aeration, investigations for the carbon and nitrogen turnover are carried out by means of both simulated aerated landfills and simulated anaerobic landfills. The results presented in this paper demonstrate that aeration is capable to enhance, both carbon mobilization and discharge via the gas phase. This effect comes along with a significant increase in bio-stabilization of the waste organic fraction, which positively affects the landfill emission behavior in the long run. In terms of leachate pollution reduction it could be demonstrated that the organic load decrease fast and widely independent of the adjusted aeration

Removal of steroid estrogens from municipal wastewater in a pilot scale expanded granular sludge blanket reactor and anaerobic membrane bioreactor

PubMed Central

Ito, Ayumi; Mensah, Lawson; Cartmell, Elise; Lester, John N.

2016-01-01

Anaerobic treatment of municipal wastewater offers the prospect of a new paradigm by reducing aeration costs and minimizing sludge production. It has been successfully applied in warm climates, but does not always achieve the desired outcomes in temperate climates at the biochemical oxygen demand (BOD) values of municipal crude wastewater. Recently the concept of ‘fortification' has been proposed to increase organic strength and has been demonstrated at the laboratory and pilot scale treating municipal wastewater at temperatures of 10–17°C. The process treats a proportion of the flow anaerobically by combining it with primary sludge from the residual flow and then polishing it to a high effluent standard aerobically. Energy consumption is reduced as is sludge production. However, no new treatment process is viable if it only addresses the problems of traditional pollutants (suspended solids – SS, BOD, nitrogen – N and phosphorus – P); it must also treat hazardous substances. This study compared three potential municipal anaerobic treatment regimes, crude wastewater in an expanded granular sludge blanket (EGSB) reactor, fortified crude wastewater in an EGSB and crude wastewater in an anaerobic membrane bioreactor. The benefits of fortification were demonstrated for the removal of SS, BOD, N and P. These three systems were further challenged with the removal of steroid estrogens at environmental concentrations from natural indigenous sources. All three systems removed these compounds to a significant degree, confirming that estrogen removal is not restricted to highly aerobic autotrophs, or aerobic heterotrophs, but is also a faculty of anaerobic bacteria. PMID:26212345

Performance and kinetic study of semi-dry thermophilic anaerobic digestion of organic fraction of municipal solid waste

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

Sajeena Beevi, B., E-mail: sajeenanazer@gmail.com; Madhu, G., E-mail: profmadhugopal@gmail.com; Sahoo, Deepak Kumar, E-mail: dksahoo@gmail.com

2015-02-15

Highlights: • Performance of the reactor was evaluated by the degradation of volatile solids. • Biogas yield at the end of the digestion was 52.9 L/kg VS. • Value of reaction rate constant, k, obtained was 0.0249 day{sup −1}. • During the digestion 66.7% of the volatile solid degradation was obtained. - Abstract: Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and waste disposal. In this study semi dry anaerobic digestion of organic solid wastes was conducted for 45 days in a lab-scale batch experiment for total solid concentration ofmore » 100 g/L for investigating the start-up performances under thermophilic condition (50 °C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9 L/kg VS (volatile solid) for the total solid (TS) concentration of 100 g/L. About 66.7% of the volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249 day{sup −1}.« less

Biogas potential from anaerobic co-digestion of faecal sludge with food waste and garden waste

NASA Astrophysics Data System (ADS)

Afifah, Ukhtiy; Priadi, Cindy Rianti

2017-03-01

The limited faecal sludge management can be optimized by converting the sludge into biogas. This study purposed to optimize the biogas potential of faecal sludge with food waste and garden waste. The system using Anaerobic Co-digestion on the variation 25% and 50% concentration of faecal sludge based on Volatile Solids (VS). Inoculum used was cow's rumen. The study was operated using lab-scale batch reactor 51 L for 42 days. Biogas produced at 25% concentration of faecal sludge is 0,30 m3CH4/kg with 71,93% VS and 72,42% COD destruction. Meanwhile, at 50% concentration of faecal sludge produce 0,56 m3CH4/kg VS biogas with 92,43% VS and 87,55% COD destruction. This study concludes that biogas potential of 50% concentration greater than 25% concentration of faecal sludge.

Anaerobic

MedlinePlus

... oxygen." The term has many uses in medicine. Anaerobic bacteria are germs that can survive and grow where ... Infections like tetanus and gangrene are caused by anaerobic bacteria. Anaerobic infections typically cause abscesses (buildups of pus), ...

Orodispersible films: Product transfer from lab-scale to continuous manufacturing.

PubMed

Thabet, Yasmin; Breitkreutz, Joerg

2018-01-15

Orodispersible films have been described as new beneficial dosage forms for special patient populations. Due to various production settings, different requirements on film formulations are required for non- continuous and continuous manufacturing. In this study, a continuous coating machine was qualified in regards of the process conditions for film compositions and their effects on the formed films. To investigate differences between both manufacturing processes, various film formulations of hydrochlorothiazide and hydroxypropylcellulose (HPC) or hydroxypropylmethycellulose (HPMC) as film formers were produced and the resulting films were characterized. The qualification of the continuously operating coating machine reveals no uniform heat distribution during drying. Coating solutions for continuous manufacturing should provide at least a dynamic viscosity of 1 Pa*s (wet film thickness of 500 μm, velocity of 15.9 cm/min). HPC films contain higher residuals of ethanol or acetone in bench-scale than in continuous production mode. Continuous production lead to lower drug content of the films. All continuously produced films disintegrate within less than 30 s. There are observed significant effects of the production process on the film characteristics. When transferring film manufacturing from lab-scale to continuous mode, film compositions, processing conditions and suitable characterization methods have to be carefully selected and adopted. Copyright © 2017 Elsevier B.V. All rights reserved.

Evolution of microorganisms in thermophilic-dry anaerobic digestion.

PubMed

Montero, B; Garcia-Morales, J L; Sales, D; Solera, R

2008-05-01

Microbial population dynamics were studied during the start-up and stabilization periods in thermophilic-dry anaerobic digestion at lab-scale. The experimental protocol was defined to quantify Eubacteria and Archaea using Fluorescent in situ hybridization (FISH) in a continuously stirred tank reactor (CSTR), without recycling solids. The reactor was subjected to a programme of steady-state operation over a range of the retention times from 40 to 25 days, with an organic loading rate between 4.42 and 7.50 kg volatile solid/m3/day. Changes in microbial concentrations were linked to traditional performance parameters such as biogas production and VS removal. The relations of Eubacteria:Archaea and H2-utilising methanogens:acetate-utilising methanogens were 88:12 and 11:1, respectively, during start-up stage. Hydrogenotrophic methanogens, although important in the initial phase of the reactor start-up, were displaced by acetoclastic methanogens at steady-state, thus their relation were 7:32, respectively. The methane yield coefficient, the methane content in the biogas and VS removal were stabilized around 0.30 LCH4/gCOD, 50% and 80%, respectively. Methanogenic population correlated well with performance measurements.

Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

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

Liu Xiao, E-mail: liuxiao07@mails.tsinghua.edu.cn; Wang Wei; Shi Yunchun

2012-11-15

Highlights: Black-Right-Pointing-Pointer Co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) was examined on a pilot-scale reactor. Black-Right-Pointing-Pointer System performance and stability under OLR of 1.2, 2.4, 3.6, 4.8, 6.0 and 8.0 kg VS (m{sup 3} d){sup -1} were analyzed. Black-Right-Pointing-Pointer A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and HRT of 15d. Black-Right-Pointing-Pointer With the increasing OLRs, pH values, VS removal rate and methane concentration decreased and VFA increased. Black-Right-Pointing-Pointer The changing of biogas production rate can be a practicalmore » approach to monitor and control anaerobic digestion system. - Abstract: The effects of organic loading rate on the performance and stability of anaerobic co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) were investigated on a pilot-scale reactor. The results showed that stable operation was achieved with organic loading rates (OLR) of 1.2-8.0 kg volatile solid (VS) (m{sup 3} d){sup -1}, with VS reduction rates of 61.7-69.9%, and volumetric biogas production of 0.89-5.28 m{sup 3} (m{sup 3} d){sup -1}. A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and hydraulic retention time of 15 days. With increasing OLRs, the anaerobic reactor showed a decrease in VS removal rate, average pH value and methane concentration, and a increase of volatile fatty acid concentration. By monitoring the biogas production rate (BPR), the anaerobic digestion system has a higher acidification risk under an OLR of 8.0 kg VS (m{sup 3} d){sup -1}. This result remarks the possibility of relating bioreactor performance with BPR in order to better understand and monitor anaerobic digestion process.« less

Diversity and degradation mechanism of an anaerobic bacterial community treating phenolic wastewater with sulfate as an electron acceptor.

PubMed

Guo, X J; Lu, Z Y; Wang, P; Li, H; Huang, Z Z; Lin, K F; Liu, Y D

2015-10-01

Petrochemical wastewater often contains high concentrations of phenol and sulfate that must be properly treated to meet discharge standards. This study acclimated anaerobic-activated sludge to treat saline phenolic wastewater with sulfate reduction and clarified the diversity and degradation mechanism of the microbial community. The active sludge in an upflow anaerobic sludge blanket (UASB) reactor could remove 90 % of phenol and maintain the effluent concentration of SO4 (2-) below 400 mg/L. Cloning and sequencing showed that Clostridium spp. and Desulfotomaculum spp. were major phenol-degrading bacteria. Phenol was probably degraded through the carboxylation pathway and sulfate reduction catalyzed by adenosine-5'-phosphosulfate (APS) reductase and dissimilatory sulfite reductase (DSR). A real-time polymerase chain reaction (RT-PCR) showed that as phenol concentration increased, the quantities of 16S rRNA gene, dsrB, and mcrA in the sludge all decreased. The relative abundance of dsrB dropped to 12.46 %, while that of mcrA increased to 56.18 %. The change in the electron flow ratio suggested that the chemical oxygen demand (COD) was removed mainly by sulfate-reducing bacteria under a phenol concentration of 420 mg/L, whereas it was removed mainly by methanogens above 630 mg/L.

Anaerobic digestion of selected Italian agricultural and industrial residues (grape seeds and leather dust): combined methane production and digestate characterization.

PubMed

Caramiello, C; Lancellotti, I; Righi, F; Tatàno, F; Taurino, R; Barbieri, L

2013-01-01

A combined experimental evaluation of methane production (obtained by anaerobic digestion) and detailed digestate characterization (with physical-chemical, thermo-gravimetric and mineralogical approaches) was conducted on two organic substrates, which are specific to Italy (at regional and national levels). One of the substrates was grape seeds, which have an agricultural origin, whereas the other substrate was vegetable-tanned leather dust, which has an industrial origin. Under the assumed experimental conditions of the performed lab-scale test series, the grape seed substrate exhibited a resulting net methane production of 175.0 NmL g volatile solids (VS)(-1); hence, it can be considered as a potential energy source via anaerobic digestion. Conversely, the net methane production obtained from the anaerobic digestion of the vegetable-tanned leather dust substrate was limited to 16.1 NmL gVS(-1). A detailed characterization of the obtained digestates showed that there were both nitrogen-containing compounds and complex organic compounds present in the digestate that was obtained from the mixture of leather dust and inoculum. As a general perspective of this experimental study, the application of diversified characterization analyzes could facilitate (1) a better understanding of the main properties of the obtained digestates to evaluate their potential valorization, and (2) a combination of the digestate characteristics with the corresponding methane productions to comprehensively evaluate the bioconversion process.

Kinetics of Anaerobic Digestion of Palm Oil Mill Effluent (POME) in Double-Stage Batch Bioreactor with Recirculation and Fluidization of Microbial Immobilization Media

NASA Astrophysics Data System (ADS)

Ramadhani, L. I.; Damayanti, S. I.; Sudibyo, H.; Budhijanto, W.

2018-03-01

Palm Oil Mill Effluent (POME) becomes big problem for palm oil industries, especially for Crude Palm Oil (CPO) industry since it produces 3 tons of POME for every ton of CPO production.The high amount of organic loading in POME makes it potential as a substrate in anaerobic digestion to generate biogas as renewable energy source. The most common but conventional method by using open lagoon is still preferred for most CPO industry in Indonesia to treat POME because of its simplicity and easiness. However, this method creates new major problem for the water bodies since it has no significant chemical oxygen demand (COD) removal and needs wide area. Besides, greenhouse gas (CH4) is also released during the process. An innovation was made in this study by designing vertical column process equipment to run an anaerobic digestion of POME. The vertical column was functioned as anaerobic fluidized bed reactor (AFBR). To enhance the digestion rate in AFBR, natural zeolite was used as the immobilization media and the inoculum was taken from digested biodiesel waste. This research aimed to determine the kinetic constants of double-stage anaerobic POME digestion for COD removal and biogas production. To get close to the real condition, the POME used in this experiment had 8,000 mg/L of sCOD (the real sCOD was ±16,000 mg/L). The experiment was conducted under room temperature with up-flow velocity between 1.75 and 2.3 cm/s for optimum fluidization of immobilization media.

Wastewater Treatment Anaerobic Digester Foaming Prevention and Control Methods - Literature Review and Survey - Full-Scale Studies (WERF Report INFR1SG10)

EPA Science Inventory

This project addresses the issue of anaerobic digester (AD) foaming in different water resource recovery facilities (WRRFs). This two-volume report is a compilation of an AD foaming literature review, a plant survey, and findings from full-scale studies. The literature review hel...

Simultaneous Microwave Extraction and Separation of Volatile and Non-Volatile Organic Compounds of Boldo Leaves. From Lab to Industrial Scale

PubMed Central

Petigny, Loïc; Périno, Sandrine; Minuti, Matteo; Visinoni, Francesco; Wajsman, Joël; Chemat, Farid

2014-01-01

Microwave extraction and separation has been used to increase the concentration of the extract compared to the conventional method with the same solid/liquid ratio, reducing extraction time and separate at the same time Volatile Organic Compounds (VOC) from non-Volatile Organic Compounds (NVOC) of boldo leaves. As preliminary study, a response surface method has been used to optimize the extraction of soluble material and the separation of VOC from the plant in laboratory scale. The results from the statistical analysis revealed that the optimized conditions were: microwave power 200 W, extraction time 56 min and solid liquid ratio of 7.5% of plants in water. Lab scale optimized microwave method is compared to conventional distillation, and requires a power/mass ratio of 0.4 W/g of water engaged. This power/mass ratio is kept in order to upscale from lab to pilot plant. PMID:24776762

Ethanol Production from Wet-Exploded Wheat Straw Hydrolysate by Thermophilic Anaerobic Bacterium Thermoanaerobacter BG1L1 in a Continuous Immobilized Reactor

NASA Astrophysics Data System (ADS)

Georgieva, Tania I.; Mikkelsen, Marie J.; Ahring, Birgitte K.

Thermophilic ethanol fermentation of wet-exploded wheat straw hydrolysate was investigated in a continuous immobilized reactor system. The experiments were carried out in a lab-scale fluidized bed reactor (FBR) at 70°C. Undetoxified wheat straw hydrolysate was used (3-12% dry matter), corresponding to sugar mixtures of glucose and xylose ranging from 12 to 41 g/1. The organism, thermophilic anaerobic bacterium Thermoanaerobacter BG1L1, exhibited significant resistance to high levels of acetic acid (up to 10 g/1) and other metabolic inhibitors present in the hydrolysate. Although the hydrolysate was not detoxified, ethanol yield in a range of 0.39-0.42 g/g was obtained. Overall, sugar efficiency to ethanol was 68-76%. The reactor was operated continuously for approximately 143 days, and no contamination was seen without the use of any agent for preventing bacterial infections. The tested microorganism has considerable potential to be a novel candidate for lignocellulose bioconversion into ethanol. The work reported here also demonstrates that the use of FBR configuration might be a viable approach for thermophilic anaerobic ethanol fermentation.

Ultrasound pre-treatment for anaerobic digestion improvement.

PubMed

Pérez-Elvira, S; Fdz-Polanco, M; Plaza, F I; Garralón, G; Fdz-Polanco, F

2009-01-01

Prior research indicates that ultrasounds can be used in batch reactors as pre-treatment before anaerobic digestion, but the specific energy required at laboratory-scale is too high. This work evaluates both the continuous ultrasound device performance (efficiency and solubilisation) and the operation of anaerobic digesters continuously fed with sonicated sludge, and presents energy balance considerations. The results of sludge solubilisation after the sonication treatment indicate that, applying identical specific energy, it is better to increase the power than the residence time. Working with secondary sludge, batch biodegradability tests show that by applying 30 kWh/m3 of sludge, it is possible to increase biogas production by 42%. Data from continuous pilot-scale anaerobic reactors (V=100 L) indicate that operating with a conventional HRT=20 d, a reactor fed with pre-treated sludge increases the volatile solids removal and the biogas production by 25 and 37% respectively. Operating with HRT=15 d, the removal efficiency is similar to the obtained with a reactor fed with non-hydrolysed sludge at HTR=20 d, although the specific biogas productivity per volume of reactor is higher for the pretreated sludge. Regarding the energy balance, although for laboratory-scale devices it is negative, full-scale suppliers state a net generation of 3-10 kW per kW of energy used.

Imaging the internal structure of fluid upflow zones with detailed digital Parasound echosounder surveys

NASA Astrophysics Data System (ADS)

Spiess, V.; Zuehlsdorff, L.; von Lom-Keil, H.; Schwenk, T.

2001-12-01

Sites of venting fluids both with continuous and episodic supply often reveal complex surface and internal structures, which are difficult to image and cause problems to transfer results from local sampling towards a structural reconstruction and a quantification of (average) flux rates. Detailed acoustic and seismic surveys would be required to retrieve this information, but also an appropriate environment, where fluid migration can be properly imaged from contrasts to unaffected areas. Hemipelagic sediments are most suitable, since typically reflectors are coherent and of low lateral amplitude variation and structures are continuous over distances much longer than the scale of fluid migration features. During RV Meteor Cruise M473 and RV Sonne Cruise SO 149 detailed studies were carried out in the vicinity of potential fluid upflow zones in the Lower Congo Basin at 5oS in 3000 m water depth and at the Northern Cascadia Margin in 1000 m water depth. Unexpected sampling of massive gas hydrates from the sea floor as well as of carbonate concretions, shell fragments and different liveforms indicated active fluid venting in a typically hemipelagic realm. The acoustic signature of such zones includes columnar blanking, pockmark depressions at the sea floor, association with small offset faults (< 1m). A dedicated survey with closely spaced grid lines was carried out with the Parasound sediment echosounder (4 kHz), which data were digitally acquired with the ParaDigMA System for further processing and display, to image the spatial structure of the upflow zones. Due to the high data density amplitudes and other acoustic properties could be investigated in a 3D volume and time slices as well as reflector surfaces were analyzed. Pronounced lateral variations of reflection amplitudes within a complex pattern indicate potential pathways for fluid/gas migration and occurrences of near-surface gas hydrate deposits, which may be used to trace detailed surface evidence from side

Modelling an industrial anaerobic granular reactor using a multi-scale approach.

PubMed

Feldman, H; Flores-Alsina, X; Ramin, P; Kjellberg, K; Jeppsson, U; Batstone, D J; Gernaey, K V

2017-12-01

The objective of this paper is to show the results of an industrial project dealing with modelling of anaerobic digesters. A multi-scale mathematical approach is developed to describe reactor hydrodynamics, granule growth/distribution and microbial competition/inhibition for substrate/space within the biofilm. The main biochemical and physico-chemical processes in the model are based on the Anaerobic Digestion Model No 1 (ADM1) extended with the fate of phosphorus (P), sulfur (S) and ethanol (Et-OH). Wastewater dynamic conditions are reproduced and data frequency increased using the Benchmark Simulation Model No 2 (BSM2) influent generator. All models are tested using two plant data sets corresponding to different operational periods (#D1, #D2). Simulation results reveal that the proposed approach can satisfactorily describe the transformation of organics, nutrients and minerals, the production of methane, carbon dioxide and sulfide and the potential formation of precipitates within the bulk (average deviation between computer simulations and measurements for both #D1, #D2 is around 10%). Model predictions suggest a stratified structure within the granule which is the result of: 1) applied loading rates, 2) mass transfer limitations and 3) specific (bacterial) affinity for substrate. Hence, inerts (X I ) and methanogens (X ac ) are situated in the inner zone, and this fraction lowers as the radius increases favouring the presence of acidogens (X su ,X aa , X fa ) and acetogens (X c4 ,X pro ). Additional simulations show the effects on the overall process performance when operational (pH) and loading (S:COD) conditions are modified. Lastly, the effect of intra-granular precipitation on the overall organic/inorganic distribution is assessed at: 1) different times; and, 2) reactor heights. Finally, the possibilities and opportunities offered by the proposed approach for conducting engineering optimization projects are discussed. Copyright © 2017 Elsevier Ltd. All

Cleavage of the main carbon chain backbone of high molecular weight polyacrylamide by aerobic and anaerobic biological treatment.

PubMed

Song, Wenzhe; Zhang, Yu; Gao, Yingxin; Chen, Dong; Yang, Min

2017-12-01

High molecular weight partially hydrolyzed polyacrylamide (PAM) can be bio-hydrolyzed on the amide side group, however, solid evidence regarding the biological cleavage of its main carbon chain backbone is limited. In this study, viscometry, flow field-flow fractionation multi-angle light scattering (FFF-MALS), and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) analysis were used to investigate the biodegradability of PAM with a nominal molecular weight of 2 × 10 7  Da (Da) in two suspended aerobic (25 and 40 °C) and two upflow anaerobic blanket reactors (35 and 55 °C) operated for 470 d under a hydraulic residence time (HRT) of 2 d. Both anaerobic and aerobic biological treatment reduced the viscosity from 2.02 cp in the influent to 1.45-1.60 cp, and reduced the molecular weight of PAM using FFF-MALS from 2.17 × 10 7  Da to less than one-third its original size. The removals of both the amide group and carbon chain backbone in the PAM molecule were further supported by the FTIR analysis. In comparison with the other conditions, thermophilic anaerobic treatment exhibited higher efficiency for PAM biodegradation. Batch test excluded the influence of temperature on the molecular weight of PAM over the range 25-55 °C, suggesting that cleavage of the main carbon chain backbone was attributed to biological degradation. Our results suggested that high molecular weight PAM was biodegradable, but mineralization did not occur. Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential use of duckweed based anaerobic digester effluent as a feed source for heterotrophic growth of micro-algae

NASA Astrophysics Data System (ADS)

Ahmadi, L.; Dupont, R.

2013-12-01

Finding an alternative source of energy for the growing world's demand is a challenging task being considered by many scientists. Various types of renewable energy alternatives are being investigated by researchers around the world. The abundance of duckweed (i.e., Lemna and Wolfia sp.) in wetlands and wastewater lagoons, their rapid growth, and their capacity for nutrient, metal and other contaminant removal from wastewater suggests their potential as an inexpensive source of biomass for biofuel production. Another source of biomass for biofuel and energy production is micro-algae. The large-scale growth of micro-algae can potentially be achieved in a smaller footprint and at a higher rate and lower cost via heterotrophic growth compared to autotrophic growth for specific species that can grow under both conditions. Here we describe two types of research. First, two lab-scale, 5 L anaerobic digesters containing municipal raw wastewater that were set up, maintained and monitored over the course of 6 months using duckweed as the feed source. The pH, salinity, amount of gas production and gas composition were measured on a daily basis. The results from these measurements show that duckweed can be used as a good source of biofuel production in the form of methane gas. The second set of reactors consisted of two 1 L batch fed reactors containing algae (Chlorella vulgaris) grown in the lab environment heterotrophically. The pH and DO were monitored on a daily basis in order to investigate their effect on algae growth. Lipid analysis of the harvested algal biomass was done to investigate the efficiency of harvestable biofuel products. A nutrient solution containing glucose as an energy source was used as the initial feed solution, and the potential substitution of the glucose solution with the organic carbon residue from the duckweed digester effluent was investigated. Methane production, carbon stabilization, and gas composition results from the duckweed fed anaerobic

Dry anaerobic digestion of cow manure and agricultural products in a full-scale plant: Efficiency and comparison with wet fermentation.

PubMed

Chiumenti, Alessandro; da Borso, Francesco; Limina, Sonia

2018-01-01

For years, anaerobic digestion processes have been implemented for the management of organic wastes, agricultural residues, and animal manure. Wet anaerobic digestion still represents the most common technology, while dry fermentation, dedicated to the treatment of solid inputs (TS>20%) can be considered as an emerging technology, not in terms of technological maturity, but of diffusion. The first agricultural dry anaerobic digestion plant constructed in Italy was monitored from the start-up, for over a year. The plant was fed with manure and agricultural products, such as corn silage, triticale, ryegrass, alfalfa, and straw. Three Combined Heat and Power units, for a total installed power of 910kW e , converted biogas into thermal and electric energy. The monitoring included the determination of quality and quantity of input feedstocks, of digestate (including recirculation rate), of leachate, biogas quality (CH 4 , CO 2 , H 2 S), biogas yield, energy production, labor requirement for loading, and unloading operations. The results of the monitoring were compared to performance data obtained in several full scale wet digestion plants. The dry fermentation plant revealed a start-up phase that lasted several months, during which the average power resulted in 641kW e (70.4% of nominal power), and the last period the power resulted in 788kW e (86.6% of installed power). Improving the balance of the input, the dry fermentation process demonstrated biogas yields similar to wet anaerobic digestion, congruent to the energy potential of the biomasses used in the process. Furthermore, the operation of the plant required significant man labor, mainly related to loading and unloading of the anaerobic cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed

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

2014-10-01

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

Decentralised treatment of concentrated sewage at low temperature in a two-step anaerobic system: two upflow-hybrid septic tanks.

PubMed

Elmitwalli, T A; Sayed, S; Groendijk, L; van Lier, J; Zeeman, G; Lettinga, G

2003-01-01

The decentralised treatment of concentrated sewage (about 3,600 mgCOD/l) at low temperature was investigated in a two-step anaerobic system: two-anaerobic hybrid (AH) septic tanks (each 0.575 m3). The two reactors were placed in a temperature controlled-room and the HRT was 2.5 days for each reactor. The system was fed with concentrated domestic sewage, mainly black water from about 40 toilets flushed with only 4 litre of water and a limited amount of grey water. The system showed high removal efficiency for the different COD fractions. Mean removal efficiencies in the two-step AH-septic tank at 5 days HRT and 13 degrees C were 94, 98, 74 and 78% for total COD, suspended COD, colloidal COD and dissolved COD respectively. The results of short run experiments indicated that the presence of reticulated polyurethane foam (RPF) media in the AH-septic tank improved the removal of suspended COD by 22%. The first AH-septic tank was full of sludge after 4 months of operation due to the high removal of particulate COD and the limited hydrolysis at low temperature conditions. Therefore, a simple mathematical model was developed based on ADM1 (the IWA model in 2002). Based on the experimental results and the mathematical model, only a one-step AH septic tank is required. An HRT of 5.5-7.5 days is needed for that one-step AH septic tank to treat concentrated sewage at a low temperature of 13 degrees C. Such a system can provide a total COD removal as high as 87% and will be full of sludge after a period of more than a year.

Method for treating wastewater using microorganisms and vascular aquatic plants

NASA Technical Reports Server (NTRS)

Wolverton, B. C. (Inventor)

1983-01-01

A method for treating wastewater compresses subjecting the wastewater to an anaerobic setting step for at least 6 hours and passing the liquid effluent from the anaerobic settling step through a filter cell in an upflow manner. There the effluent is subjected first to the action of anaerobic and facultative microorganisms, and then to the action of aerobic microorganisms and the roots of at least one vascular aquatic plant.

Methanogenic population dynamics during startup of a full-scale anaerobic sequencing batch reactor treating swine waste.

PubMed

Angenent, Largus T; Sung, Shihwu; Raskin, Lutgarde

2002-11-01

Changes in methanogenic population levels were followed during startup of a full-scale, farm-based anaerobic sequencing batch reactor (ASBR) and these changes were linked to operational and performance data. The ASBR was inoculated with anaerobic digester sludge from a municipal wastewater treatment facility. During an acclimation period of approximately 3 months, the ASBR content was diluted to maintain a total ammonia-N level of approximately 2000mg l(-1). After this acclimation period, the volatile solids loading rate was increased to its design value of 1.7g l(-1) day(-1) with a 15-day hydraulic retention time, which increased the total ammonia-N level in the ASBR to approximately 3,600 mg l(-1). The 16S ribosomal RNA (rRNA) levels of the acetate-utilizing methanogens of the genus Methanosarcina decreased from 3.8% to 1.2% (expressed as a percentage of the total 16S rRNA levels) during this period, while the 16S rRNA levels of Methanosaeta concilii remained low (below 2.2%). Methane production and reactor performance were not affected as the 16S rRNA levels of the hydrogen-utilizing methanogens of the order Methanomicrobiales increased from 2.3% to 7.0%. Hence, it is likely that during operation with high ammonia levels, the major route of methane production is through a syntrophic relationship between acetate-oxidizing bacteria and hydrogen-utilizing methanogens. Anaerobic digestion at total ammonia-N levels exceeding 3500mg l(-1) was sustainable apparently due to the acclimation of hydrogen-utilizing methanogens to high ammonia levels.

Effect of electrode position on azo dye removal in an up-flow hybrid anaerobic digestion reactor with built-in bioelectrochemical system

NASA Astrophysics Data System (ADS)

Cui, Min-Hua; Cui, Dan; Lee, Hyung-Sool; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

2016-04-01

In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m3·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment.

Microaerobic DO-induced microbial mechanisms responsible for enormous energy saving in upflow microaerobic sludge blanket reactor.

PubMed

Zheng, Shaokui; Cui, Cancan; Quan, Ying; Sun, Jian

2013-07-01

This study experimentally examined the microaerobic dissolved oxygen (DO)-induced microbial mechanisms that are responsible for enormous energy savings in the upflow microaerobic sludge blanket reactor (UMSB) for domestic wastewater treatment. Phylogenetic and kinetic analyses (as determined by clone library analyses and sludge oxygen affinity analyses) showed that the microaerobic conditions in the UMSB led to the proliferation and dominance of microaerophilic bacteria that have higher oxygen affinities (i.e., lower sludge oxygen half-saturation constant values), which assured efficient COD and NH3-N removals and sludge granulation in the UMSB similar as those achieved in the aerobic control. However, the microaerobic DO level in the UMSB achieved significant short-cut nitrification, a 50-90% reduction in air supply, and an 18-28% reduction in alkali consumption. Furthermore, the disappearance of sludge bulking in the UMSB when it was dominated by "bulking-induced" filamentous bacteria should be attributed to its upflow column-type configuration. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

PubMed

Grübel, Klaudiusz; Suschka, Jan

2015-05-01

The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

The Immersive Virtual Reality Lab: Possibilities for Remote Experimental Manipulations of Autonomic Activity on a Large Scale.

PubMed

Juvrud, Joshua; Gredebäck, Gustaf; Åhs, Fredrik; Lerin, Nils; Nyström, Pär; Kastrati, Granit; Rosén, Jörgen

2018-01-01

There is a need for large-scale remote data collection in a controlled environment, and the in-home availability of virtual reality (VR) and the commercial availability of eye tracking for VR present unique and exciting opportunities for researchers. We propose and provide a proof-of-concept assessment of a robust system for large-scale in-home testing using consumer products that combines psychophysiological measures and VR, here referred to as a Virtual Lab. For the first time, this method is validated by correlating autonomic responses, skin conductance response (SCR), and pupillary dilation, in response to a spider, a beetle, and a ball using commercially available VR. Participants demonstrated greater SCR and pupillary responses to the spider, and the effect was dependent on the proximity of the stimuli to the participant, with a stronger response when the spider was close to the virtual self. We replicated these effects across two experiments and in separate physical room contexts to mimic variability in home environment. Together, these findings demonstrate the utility of pupil dilation as a marker of autonomic arousal and the feasibility to assess this in commercially available VR hardware and support a robust Virtual Lab tool for massive remote testing.

The Immersive Virtual Reality Lab: Possibilities for Remote Experimental Manipulations of Autonomic Activity on a Large Scale

PubMed Central

Juvrud, Joshua; Gredebäck, Gustaf; Åhs, Fredrik; Lerin, Nils; Nyström, Pär; Kastrati, Granit; Rosén, Jörgen

2018-01-01

There is a need for large-scale remote data collection in a controlled environment, and the in-home availability of virtual reality (VR) and the commercial availability of eye tracking for VR present unique and exciting opportunities for researchers. We propose and provide a proof-of-concept assessment of a robust system for large-scale in-home testing using consumer products that combines psychophysiological measures and VR, here referred to as a Virtual Lab. For the first time, this method is validated by correlating autonomic responses, skin conductance response (SCR), and pupillary dilation, in response to a spider, a beetle, and a ball using commercially available VR. Participants demonstrated greater SCR and pupillary responses to the spider, and the effect was dependent on the proximity of the stimuli to the participant, with a stronger response when the spider was close to the virtual self. We replicated these effects across two experiments and in separate physical room contexts to mimic variability in home environment. Together, these findings demonstrate the utility of pupil dilation as a marker of autonomic arousal and the feasibility to assess this in commercially available VR hardware and support a robust Virtual Lab tool for massive remote testing. PMID:29867318

Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes.

PubMed

García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh; Lema, Juan M; Rodríguez, Jorge; Steyer, Jean-Philippe; Torrijos, Michel

2015-01-01

A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 gVS/Ld. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Does the addition of proteases affect the biogas yield from organic material in anaerobic digestion?

PubMed

Müller, Liane; Kretzschmar, Jörg; Pröter, Jürgen; Liebetrau, Jan; Nelles, Michael; Scholwin, Frank

2016-03-01

The aim of this study was to investigate the biochemical disintegration effect of hydrolytic enzymes in lab scale experiments. Influences of enzyme addition on the biogas yield as well as effects on the process stability were examined. The addition of proteases occurred with low and high dosages in batch and semi-continuous biogas tests. The feed mixture consisted of maize silage, chicken dung and cow manure. Only very high concentrated enzymes caused an increase in biogas production in batch experiments. In semi-continuous biogas tests no positive long-term effects (100 days) were observed. Higher enzyme-dosage led to a reduced biogas-yield (13% and 36% lower than the reference). Phenylacetate and -propionate increased (up to 372 mgl(-1)) before the other volatile fatty acids did. Volatile organic acids rose up to 6.8 gl(-1). The anaerobic digestion process was inhibited. Copyright © 2015 Elsevier Ltd. All rights reserved.

Molecular Ions in Ion Upflows and their Effects on Hot Atomic Oxygen Production

NASA Astrophysics Data System (ADS)

Foss, V.; Yau, A. W.; Shizgal, B.

2017-12-01

We present new direct ion composition observations of molecular ions in auroral ion upflows from the CASSIOPE Enhanced Polar Outflow Probe (e-POP). These observed molecular ions are N2+, NO+, and possibly O2+, and are found to occur at all e-POP altitudes starting at about 400 km, during auroral substorms and the different phases of magnetic storms, sometimes with upflow velocities exceeding a few hundred meters per second and abundances of 5-10%. The dissociative recombination of both O2+ and NO+ was previously proposed as an important source of hot oxygen atoms in the topside thermosphere [Hickey et al., 1995]. We investigate the possible effect of the observed molecular ions on the production of hot oxygen atoms in the storm and substorm-time auroral thermosphere. We present numerical solutions of the Boltzmann equation for the steady-state oxygen energy distribution function, taking into account both the production of the hot atoms and their subsequent collisional relaxation. Our result suggests the formation of a hot oxygen population with a characteristic temperature on the order of 0.3 eV and constituting 1-5% of the oxygen density near the exobase. We discuss the implication of this result in the context of magnetosphere-ionosphere-thermosphere coupling.

Identification and characterization of odorous gas emission from a full-scale food waste anaerobic digestion plant in China.

PubMed

Kong, Xin; Liu, Jianguo; Ren, Lianhai; Song, Minying; Wang, Xiaowei; Ni, Zhe; Nie, Xiaoqin

2015-10-01

Odorous gas emission characteristic along with the successive processes of a typical full-scale food waste (FW) anaerobic digestion plant in China was investigated in September and January. Seasonal variations in pollutant concentration and principal component analysis (PCA) showed markedly different characteristics between the two months. However, the main reason for the seasonal difference at the sorting process differed from the reason for the seasonal difference at other treatment units. Most odorous volatile organic compound (VOC) concentrations tested near an anaerobic digestion tank were similar and low in both months. Odor indices, including odor contribution (OC) and odor activity value (OAV) of various odorants, were further calculated to evaluate the malodor degree and contribution to the nuisance smell of any odorant. Brought about by people's different dietary habits, H2S and sulfocompounds were found to be dominant contributors to the large total OVA in the January test. By contrast, oxygenated organic compounds played an important role on the sum of OVA in September.

[Isolation and characterization of Thermopirellula anaerolimosa gen. nov., sp. nov., an obligate anaerobic hydrogen-producing bacterium of the phylum Planctomycetes].

PubMed

Liu, Dongying; Liu, Yi; Men, Xuehui; Guo, Qunqun; Guo, Rongbo; Qiu, Yanling

2012-08-04

To cultivate various yet-to-be cultured heterotrophs from anaerobic granule sludge, we used a selective culture medium with low concentrations of substrates supplemented a variety of antibiotics. An obligate anaerobic, thermophilic, hydrogen-producing bacterium, strain VM20-7(T), was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating high-strength organic wastewater from isomerized sugar production processes. Cells of strain VM20-7(T) are non-motile, spherical, pear or teardrop shaped, occurring singly(o)r as aggregates (0.7 - 2.0 microm x 0.7 - 2.0 microm). Spore formation was not observed. Growth temperature ranges from 35 - 50 degrees C (optimum 45 degrees C), pH ranges from 6.0 - 8.3 (optimum 7.0 - 7.5) , NaCl tolerant concentration ranges from 0% - 0.5% (w/v, optimum 0% ). Nitrate, sulfate, thiosulfate, sulfite, elemental sulfur and Fe (III)-NTA were not used as terminal electron acceptors. Strain VM20-7(T) utilizes a wide range of carbohydrates, including glucose, maltose, ribose, xylose, sucrose, galactose, mannose, raffinose, pectin, yeast extract and xylan. Acetate and H2 are the main end products of glucose fermentation. The G + C content of the genomic DNA was 60.9 mol%. 16S rRNA gene sequence analysis revealed that it is related to the Pirellula-Rhodopirellula-Blastopirellula (PRB) clade within the order Planctomycetales (82.7 - 84.3% similarity with 16S rRNA genes of other known related species). The first obligate anaerobic bacterium within the phylum Planctomycetes was isolated with low concentration of carbohydrates and antibiotics. On the basis of the physiological and phylogenetic data, the name Thermopirellula anaerolimosa gen. nov. , sp. nov. is proposed for strain VM20-7(T) (= CGMCC 1.5169(T) = JCM 17478(T) = DSM 24165(T)).

Effect of electrode position on azo dye removal in an up-flow hybrid anaerobic digestion reactor with built-in bioelectrochemical system

PubMed Central

Cui, Min-Hua; Cui, Dan; Lee, Hyung-Sool; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

2016-01-01

In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m3·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment. PMID:27121278

Simple, rapid and effective preservation and reactivation of anaerobic ammonium oxidizing bacterium "Candidatus Brocadia sinica".

PubMed

Ali, Muhammad; Oshiki, Mamoru; Okabe, Satoshi

2014-06-15

It is still the biggest challenge to secure enough seeding biomass for rapid start-up of full-scale (anaerobic ammonium oxidation) anammox processes due to slow growth. Preservation of active anammox biomass could be one of the solutions. In this study, biomass of anammox bacterium, "Candidatus Brocadia sinica", immersed in various nutrient media were preserved at -80 °C, 4 °C and room temperature. After 45, 90 and 150 days of preservation, specific anammox activity (SAA) of the preserved anammox biomass was determined by measuring (29)N2 production rate and transcription levels of hzsA gene encoding hydrazine synthase alpha subunit. Storage in nutrient medium containing 3 mM of molybdate at room temperature with periodical (every 45 days) supply of NH4(+) and NO2(-) was proved to be the most effective storage technique for "Ca. Brocadia sinica" biomass. Using this preservation condition, 96, 92 and 65% of the initial SAA was sustained after 45, 90 and 150 days of storage, respectively. Transcription levels of hzsA gene in biomass correlated with the SAA (R(2) = 0.83), indicating it can be used as a genetic marker to evaluate the anammox activity of preserved biomass. Furthermore, the 90-day-stored biomass was successfully reactivated by immobilizing in polyvinyl alcohol (6%, w/v) and sodium alginate (2%, w/v) gel and then inoculated to up-flow column reactors. Total nitrogen removal rates rapidly increased to 7 kg-N m(-3) d(-1) within 35 days of operation. Based on these results, the room temperature preservation with molybdate addition is simple, cost-effective and feasible at a practical scale, which will accelerate the practical use of anammox process for wastewater treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of the biomethane potential from multiple waste streams for a proposed community scale anaerobic digester.

PubMed

Browne, James D; Allen, Eoin; Murphy, Jerry D

2013-01-01

This paper examines the biomethane potential from organic waste for a proposed community scale anaerobic digester in a rural town. The biomethane potential test is used to assess the suitability of waste streams for biomethane production and to examine the variation in biomethane potential between waste sub-streams. A methodology for accurately estimating the biomethane potential from multiple heterogeneous organic waste substrates is sought. Five main waste streams were identified as possible substrates for biogas production, namely Abattoir waste (consisting of paunch and de-watered activated sludge); cheese factory effluent; commercial and domestic food waste; pig slurry and waste water treatment sludge. The biomethane potential of these waste streams ranged from as low as 99 L CH4 kg VS(-1) for pig slurry to as high as 787 L CH4 kg VS(-1) for dissolved air floatation (DAF) sludge from a cheese effluent treatment plant. The kinetic behaviour of the biomethane production in the batch test is also examined. The objective of the paper is to suggest an optimum substrate mix in terms of biomethane yield per unit substrate for the proposed anaerobic digester. This should maximize the yield of biomethane per capital investment. Food waste displayed the highest biomethane yield (128 m(n)(3) t(-1)) followed by cheese waste (38 m(n)(3) t(-1)) and abattoir waste (36 m(n)(3) t(-1)). It was suggested that waste water sludge (16 m(n)(3) t(-1)) and pig slurry (4 m(n)(3) t(-1)) should not be digested. However, the biomethane potential test does not give information on the continuous operation of an anaerobic digester.

[Anaerobic bacteria isolated from patients with suspected anaerobic infections].

PubMed

Ercis, Serpil; Tunçkanat, Ferda; Hasçelik, Gülşen

2005-10-01

The study involved 394 clinical samples sent to the Clinical Microbiology Laboratory of Hacettepe University Adult Hospital between January 1997 and May 2004 for anaerobic cultivation. Since multiple cultures from the same clinical samples of the same patient were excluded, the study was carried on 367 samples. The anaerobic cultures were performed in anaerobic jar using AnaeroGen kits (Oxoid, Basingstoke, U.K.) or GENbox (bioMérieux, Lyon, France). The isolates were identified by both classical methods and "BBL Crystal System" (Becton Dickinson, U.S.A.). While no growth was detected in 120 (32.7%) of the clinical samples studied, in 144 samples (39.2%) only aerobes, in 28 (7.6%) only anaerobes and in 75 (20.5%) of the samples both aerobes and anaerobes were isolated. The number of the anaerobic isolates was 217 from 103 samples with anaerobic growth. Of these 103 samples 15 showed single bacterial growth whereas in 88 samples multiple bacterial isolates were detected. Anaerobic isolates consisted of 92 Gram negative bacilli (Bacteroides spp. 50, Prevotella spp. 14, Porphyromonas spp. 10, Fusobacterium spp. 7, Tisierella spp. 2, unidentified 9), 57 Gram positive bacilli (Clostridium spp.17, Propionibacterium spp. 16, Lactobacillus spp. 8, Actinomyces spp. 5, Eubacterium spp. 2, Bifidobacterium adolescentis 1, Mobiluncus mulieris 1, unidentified nonspore forming rods 7), 61 Gram positive cocci (anaerobic cocci 44, microaerophilic cocci 17), and 7 Gram negative cocci (Veillonella spp.). In conclusion, in the samples studied with prediagnosis of anaerobic infection, Bacteroides spp. (23%) were the most common bacteria followed by anaerobic Gram positive cocci (20.3%) and Clostridium spp (7.8%).

Observation and Modeling of the Generation Mechanism of Ion Upflow during Sudden Commencement

NASA Astrophysics Data System (ADS)

Zou, S.; Ozturk, D. S.; Li, C.; Varney, R. H.; Reimer, A.

2017-12-01

Sudden commencement (SC) induced by solar wind pressure enhancement can produce significant global impact on the coupled magnetosphere-ionosphere (MI) system, and its effects have been studied extensively using ground magnetometers and coherent scatter radars. However, very limited observations have been reported about the effects of SC on the ionospheric plasma. We study the ionosphere response to the SC using the Poker Flat incoherent scatter radar (PFISR) and numerical simulations. A detailed case study of SC during the 17 March 2015 storm was conducted. PFISR observed lifting of the F region ionosphere, transient field-aligned ion upflow, prompt but short-lived ion temperature increase, subsequent F region density decrease, and persistent electron temperature increase. A global magnetohydrodynamic (MHD) simulation has been carried out to characterize the SC-induced current, convection, and magnetic perturbations. Simulated magnetic perturbations at Poker Flat show a satisfactory agreement with observations. The simulation provides a global context for linking localized PFISR observations to large-scale dynamic processes in the MI system. Following the case study, we also perform a statistical study of the effects of SC on the ionosphere focusing on the magnetic local time and latitudinal asymmetries using PFISR and GPS TEC.

Potential Application of Anaerobic Extremophiles for Hydrogen Production

NASA Technical Reports Server (NTRS)

Pikuta, Elena V.; Hoover, Richard B.

2004-01-01

During substrate fermentation many anaerobes produce the hydrogen as a waste product, which often regulates the growth of the cultures as an inhibitor. In nature the hydrogen is usually removed from the ecosystem due to its physical properties or by consumption of hydrogen by secondary anaerobes, which sometimes behave as competitors for electron donors as is seen in the classical example in anaerobic microbial communities via the interaction between methanogens and sulfate- or sulfur- reducers. It was demonstrated previously on mixed cultures of anaerobes at neutral pH that bacterial hydrogen production could provide an alternative energy source. But at neutral pH the original cultures can easily be contaminated by methanogens, a most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and the cultivation of human pathogens on a global scale is very dangerous. In our laboratory, experiments with obligately alkaliphilic bacteria that excrete hydrogen as the end metabolic product were performed at different temperature regimes. Mesophilic and moderately thermophilic bacterial cultures have been studied and compared for the most effective hydrogen production. For high-mineralized media with pH 9.5-10.0 not many methanogens are known to exist. Furthermore, the development of pathogenic contaminant microorganisms is virtually impossible: carbonate-saturated solutions are used as antiseptics in medicine. Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as most safe process for global Scale industry in future. Here we present experimental data on the rates of hydrogen productivity for mesophilic, alkaliphilic, obligately anaerobic bacterium Spirocheta americana ASpG1 and moderately thermophilic, alkaliphilic, facultative anaerobe Anoxybacillus pushchinoensis K1 and

Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems.

PubMed

Luostarinen, Sari; Sanders, Wendy; Kujawa-Roeleveld, Katarzyna; Zeeman, Grietje

2007-03-01

The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The results indicated the feasibility of the UASB-septic tank for (pre)treatment of black water at low temperatures with respect to removal of suspended solids and dissolved organic material. Inoculum sludge had little effect on COD(ss) removal, though in the start-up phase some poorly adapted inoculum disintegrated and washed out, thus requiring consideration when designing the process. Removal of COD(dis) was at first negative, but improved as the sludge adapted to low temperature. The UASB-septic tank alone did not comply with Finnish or Dutch treatment requirements and should therefore be considered mainly as a pre-treatment method. However, measuring the requirements as mgCOD l(-1) may not always be the best method, as the volume of the effluent discharged is also an important factor in the final amount of COD entering the receiving water bodies.

Cocoa residues as viable biomass for renewable energy production through anaerobic digestion.

PubMed

Acosta, Nayaret; De Vrieze, Jo; Sandoval, Verónica; Sinche, Danny; Wierinck, Isabella; Rabaey, Korneel

2018-05-31

The aim of this work was to evaluate the bioenergy potential of cocoa residue via anaerobic digestion. Batch and fed-batch lab-scale reactors were operated under low and high solids conditions. In the batch tests, 59 ± 4% of Chemical Oxygen Demand (COD) was recovered as methane. This corresponded with an average methane yield of 174 (wet) and 193 (dry) L kg -1 volatile solids fed, whereas a series of fed-batch reactors produced 70 ± 24 (wet) and 107 ± 39 (dry) L CH 4  kg -1 volatile solids fed during stable conditions. A case study was developed for canton Balao (Ecuador) based on our experimental data, operational estimates and available cocoa waste in the area. Annually, 8341 MWh could be produced, meeting 88% of the current electricity demand in Balao. This case study proves the potential for cocoa waste as a source of renewable energy in rural areas. Copyright © 2018 Elsevier Ltd. All rights reserved.

Analysis and modeling of metals release from MBT wastes through batch and up-flow column tests.

PubMed

Pantini, Sara; Verginelli, Iason; Lombardi, Francesco

2015-04-01

The leaching behavior of wastes coming out from Mechanical Biological Treatment (MBT) plants is still poorly investigated in literature. This work presents an attempt to provide a deeper insight about the contaminants release from this type of waste. To this end, results of several batch and up-flow percolation tests, carried out on different biologically treated waste samples collected from an Italian MBT plant, are reported. The obtained results showed that, despite MBT wastes are characterized by relatively high heavy metals content, only a limited amount was actually soluble and thus bioavailable. Namely, the release percentage was generally lower than 5% of the total content with the only exception of dissolved organic carbon (DOC), Zn, Ni and Co with release percentages up to 20%. The information provided by the different tests also allowed to highlight some key factors governing the kinetics release of DOC and metals from this type of material. In particular, results of up-flow column percolation tests showed that metals such as Cr, Mg, Ni and Zn followed essentially the leaching trend of DOC suggesting that these elements were mainly released as organo-compounds. Actually, a strong linear correlation (R(2) > 0.8) between DOC and metals concentration in eluates was observed, especially for Cr, Ni and Zn (R(2)>0.94). Thus, combining the results of batch and up-flow column percolation tests, partition coefficients between DOC and metals concentration were derived. These data, coupled with a simplified screening model for DOC release, allowed to get a very good prediction of metal release during the different column tests. Finally, combining the experimental data with a simplified model provided some useful indications for the evaluation of long-term emissions from this type of waste in landfill disposal scenarios. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluating inhibition conditions in high-solids anaerobic digestion of organic fraction of municipal solid waste.

PubMed

Schievano, Andrea; D'Imporzano, Giuliana; Malagutti, Luca; Fragali, Emilio; Ruboni, Gabriella; Adani, Fabrizio

2010-07-01

High-solids anaerobic digestion (HSAD) processes, when applied to different types of organic fractions of municipal solid waste (OFMSW), may easily be subjected to inhibition due to organic overloading. In this study, a new approach for predicting these phenomena was proposed based on the estimation of the putrescibility (oxygen consumption in 20 h biodegradation, OD(20)) of the organic mixtures undergoing the HSAD process. Different wastes exhibiting different putrescibility were subjected to lab-scale batch-HSAD. Measuring the organic loading (OL) as volatile solids (VS) was found unsuitable for predicting overload inhibition, because similar VS contents corresponded to both inhibited and successful trials. Instead, the OL calculated as OD(20) was a very good indicator of the inhibiting conditions (inhibition started for OD(20)>17-18 g O(2)kg(-1)). This new method of predicting inhibition in the HSAD process of diverse OFMSW may be useful for developing a correct approach to the technology in very different contexts. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Biological denitrification of high concentration nitrate waste

DOEpatents

Francis, Chester W.; Brinkley, Frank S.

1977-01-01

Biological denitrification of nitrate solutions at concentrations of greater than one kilogram nitrate per cubic meter is accomplished anaerobically in an upflow column having as a packing material a support for denitrifying bacteria.

Laboratory-scale anaerobic sequencing batch reactor for treatment of stillage from fruit distillation.

PubMed

Rada, Elena Cristina; Ragazzi, Marco; Torretta, Vincenzo

2013-01-01

This work describes batch anaerobic digestion tests carried out on stillages, the residue of the distillation process on fruit, in order to contribute to the setting of design parameters for a planned plant. The experimental apparatus was characterized by three reactors, each with a useful volume of 5 L. The different phases of the work carried out were: determining the basic components of the chemical oxygen demand (COD) of the stillages; determining the specific production of biogas; and estimating the rapidly biodegradable COD contained in the stillages. In particular, the main goal of the anaerobic digestion tests on stillages was to measure the parameters of specific gas production (SGP) and gas production rate (GPR) in reactors in which stillages were being digested using ASBR (anaerobic sequencing batch reactor) technology. Runs were developed with increasing concentrations of the feed. The optimal loads for obtaining the maximum SGP and GPR values were 8-9 gCOD L(-1) and 0.9 gCOD g(-1) volatile solids.

Perspectives on ecological research at the Outdoor StreamLab, a field-scale experimental stream

NASA Astrophysics Data System (ADS)

Merten, E. C.; Dieterman, D.; Kramarczuk, K.; Lightbody, A.; Orr, C. H.; Wellnitz, T.

2009-12-01

Artificial streams hold great promise for examining ecological processes. They lend themselves to manipulations of discharge, sediment load, water chemistry, and other parameters difficult or impossible to control in natural streams. However, artificial streams also have important limitations. In this presentation we describe insights gained from several ecological studies conducted at the St. Anthony Falls Laboratory’s Outdoor StreamLab, including, 1) short-term turbidity exposure effects on fish health, 2) macroinvertebrate grazing rates on periphyton as a function of velocity, 3) rates of macroinvertebrate colonization as related to velocity, and 4) fine-scale correlations of periphytic biomass with hydraulic conditions. Several lessons emerge from these initial attempts at ecological research in the Outdoor StreamLab. We have learned that the size, flow rate, substrate, water chemistry, and available colonization population of the artificial stream limit the kinds of organisms and types of ecological processes that can be examined and the types of experiments that can be run. We suggest that short-term biotic responses are best for study in a system of this type, and note that constant experiment maintenance is essential. Operating artificial streams to meet the needs of multiple researchers also presents challenges of scheduling, coordination, and conflict resolution. Although ecological research in artificial streams has considerable potential, the planning required is no less than that of traditional field studies.

Treatment and Energy Valorisation of an Agro-Industrial Effluent in Upflow Anaerobic Sludge Reactor (UASB)

NASA Astrophysics Data System (ADS)

Martins, Ramiro; Boaventura, Rui; Paulista, Larissa

2017-12-01

The accelerated growth of the population brings with it an increase in the generation of agro-industrial effluents. The inadequate discharge of these effluents significantly affects the quality of water resources. In this way, it becomes important to invest in treatment processes for agro-industrial effluents, particularly low-cost ones. In this context, the present study includes the design and construction of an UASB reactor and optimization of the anaerobic digestion treatment of the raw effluent from sweet chestnut production in the agro-industrial company Sortegel. The efficiency of the system was evaluated through the determination / monitoring of oxygen chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), biogas production rate and quality (% methane). The reactor was fed for 25 weeks and operated under mesophilic conditions (temperature 30-40 °C). Different values were tested for the hydraulic retention time (HRT) and volumetric flow rate (VF): 0.66 days (VF=1509 L.m-3.d-1); 1.33 days (VF=755 L.m-3.d-1); 2.41 d days (VF=415 L.m-3.d-1). The average COD removal efficiency reached values of 69%, 82% and 75%, respectively, and simultaneously the associated BOD5 removal efficiency was 84%, 91% and 70%. As regards TSS, removal values were 78%, 94% and 63%. In addition, high methane production rates were obtained, between 2500 and 4800 L CH4.kg-1 COD removed d-1. For all the hydraulic retention times tested, high concentrations of methane in the biogas were recorded: 66-75%, 70% and 75% for HRT of 0.66, 1.33 and 2.41 days, respectively.

Effects of pH buffering agents on the anaerobic hydrolysis acidification stage of kitchen waste.

PubMed

Wang, Yaya; Zang, Bing; Gong, Xiaoyan; Liu, Yu; Li, Guoxue

2017-10-01

This study investigated effects of initial pH buffering agents on the lab-scale anaerobic hydrolysis acidification stage of kitchen waste (KW). Different cheap, available and suitable buffering agents (NaOH(s), NaOH(l), CaO(s)-NaOH, KOH(l)-NaOH, K 2 HPO 4 (s)-KOH, Na 2 CO 3 (s)-NaOH) were added under optimal adjusting mode (first two days: per 16h, after: one time per day) which was obtained in previous work. The effects of buffering agents were evaluated according to indexes of pH, VFAs, NH 4 + -N, TS, VS, VS/TS, TS and VS removal rate. The results showed treatment 5 with adding K 2 HPO 4 -KOH buffering agents had the most stable pH (6.7-7.0). Also treatment 5, 2, 4 and 6 provided stable pH ranging in 5-8. Among the treatments, treatment 6 with adding Na 2 CO 3 as initial buffering agents and 10mol/L NaOH as regulator was chosen as the optimal mode for highest VFAs content (44.05g/L) with high acetic acid and butyrate acid proportion (42.64%), TS and VS removal rate (44.84% and 58.67%, respectively), low VS/TS ratio (58.55), fewer adding dosage and low adjusting frequency. The VFAs content of treatment 6 at the end of hydrolysis acidification stage could be used for methanogenic phase of anaerobic two-phase digestion. Thus, treatment 6 (adding Na 2 CO 3 as initial buffering agents and 10mol/L NaOH as regulator) with highest VFAs content and TS and VS removal rate could be considered using in anaerobic hydrolysis acidification stage pH adjustment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stream piracy in the Black Hills: A geomorphology lab exercise

USGS Publications Warehouse

Zaprowski, B.J.; Evenson, E.B.; Epstein, J.B.

2002-01-01

The Black Hills of South Dakota exhibits many fine examples of stream piracy that are very suitable for teaching geomorphology lab exercises. This lab goes beyond standard topographic map interpretation by using geologic maps, well logs, gravel provenance and other types of data to teach students about stream piracy. Using a step-by-step method in which the lab exercises ramp up in difficulty, students hone their skills in deductive reasoning and data assimilation. The first exercises deal with the identification of stream piracy at a variety of spatial scales and the lab culminates with an exercise on landscape evolution and drainage rearrangement.

Intensification of anaerobic digestion efficiency with use of mechanical excess sludge disintegration in the context of increased energy production in wastewater treatment plants

NASA Astrophysics Data System (ADS)

Żubrowska-Sudoł, Monika; Podedworna, Jolanta; Bisak, Agnieszka; Sytek-Szmeichel, Katarzyna; Krawczyk, Piotr; Garlicka, Agnieszka

2017-11-01

The main goal of the study was to evaluate the effects of mechanical sludge disintegration for enhancing full scale anaerobic digestion of municipal sludge. Batch disintegration tests and lab dewatering tests were also performed aiming at determining the release of organic compounds and assessing the impact of disintegration of excess sludge before the fermentation process of mixed sludge on the dewaterability of post-fermented sludge, respectively. In the study a disc disintegrator driven by a motor with a power of 30 kW, revolutions n = 2950 rpm has been used. It was shown that with increase of energy consumed in the disintegration, the increased amounts of organic compounds were released from the sludge. It was also documented that the introduction of the excess sludge disintegration prior to fermentation tank, resulted in a significant increase in biogas production (by an average of 33.9%) and in increase in volatile total solids reduction in the fermented sludge (by an average of 22.7%). Moreover, the obtained results indicate the possibility of obtaining a higher degree of sludge dewatering, which was subjected to anaerobic stabilization with using disintegrated excess sludge.

Anaerobic co-digestion of the organic fraction of municipal solid waste with FOG waste from a sewage treatment plant: Recovering a wasted methane potential and enhancing the biogas yield

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

Martin-Gonzalez, L., E-mail: lucia.martin@uab.ca; Colturato, L.F.; Font, X.

2010-10-15

Anaerobic digestion is applied widely to treat the source collected organic fraction of municipal solid wastes (SC-OFMSW). Lipid-rich wastes are a valuable substrate for anaerobic digestion due to their high theoretical methane potential. Nevertheless, although fat, oil and grease waste from sewage treatment plants (STP-FOGW) are commonly disposed of in landfill, European legislation is aimed at encouraging more effective forms of treatment. Co-digestion of the above wastes may enhance valorisation of STP-FOGW and lead to a higher biogas yield throughout the anaerobic digestion process. In the present study, STP-FOGW was evaluated as a co-substrate in wet anaerobic digestion of SC-OFMSWmore » under mesophilic conditions (37 {sup o}C). Batch experiments carried out at different co-digestion ratios showed an improvement in methane production related to STP-FOGW addition. A 1:7 (VS/VS) STP-FOGW:SC-OFMSW feed ratio was selected for use in performing further lab-scale studies in a 5 L continuous reactor. Biogas yield increased from 0.38 {+-} 0.02 L g VS{sub feed}{sup -1} to 0.55 {+-} 0.05 L g VS{sub feed}{sup -1} as a result of adding STP-FOGW to reactor feed. Both VS reduction values and biogas methane content were maintained and inhibition produced by long chain fatty acid (LCFA) accumulation was not observed. Recovery of a currently wasted methane potential from STP-FOGW was achieved in a co-digestion process with SC-OFMSW.« less

Anaerobic co-digestion of the organic fraction of municipal solid waste with FOG waste from a sewage treatment plant: recovering a wasted methane potential and enhancing the biogas yield.

PubMed

Martín-González, L; Colturato, L F; Font, X; Vicent, T

2010-10-01

Anaerobic digestion is applied widely to treat the source collected organic fraction of municipal solid wastes (SC-OFMSW). Lipid-rich wastes are a valuable substrate for anaerobic digestion due to their high theoretical methane potential. Nevertheless, although fat, oil and grease waste from sewage treatment plants (STP-FOGW) are commonly disposed of in landfill, European legislation is aimed at encouraging more effective forms of treatment. Co-digestion of the above wastes may enhance valorisation of STP-FOGW and lead to a higher biogas yield throughout the anaerobic digestion process. In the present study, STP-FOGW was evaluated as a co-substrate in wet anaerobic digestion of SC-OFMSW under mesophilic conditions (37 degrees C). Batch experiments carried out at different co-digestion ratios showed an improvement in methane production related to STP-FOGW addition. A 1:7 (VS/VS) STP-FOGW:SC-OFMSW feed ratio was selected for use in performing further lab-scale studies in a 5L continuous reactor. Biogas yield increased from 0.38+/-0.02 L g VS(feed)(-1) to 0.55+/-0.05 L g VS(feed)(-1) as a result of adding STP-FOGW to reactor feed. Both VS reduction values and biogas methane content were maintained and inhibition produced by long chain fatty acid (LCFA) accumulation was not observed. Recovery of a currently wasted methane potential from STP-FOGW was achieved in a co-digestion process with SC-OFMSW. (c) 2010 Elsevier Ltd. All rights reserved.

Implementation and process analysis of pilot scale multi-phase anaerobic fermentation and digestion of faecal sludge in Ghana

PubMed Central

Shih, Justin; Fanyin-Martin, Ato; Taher, Edris; Chandran, Kartik

2017-01-01

Background.  In Ghana, faecal sludge (FS) from on-site sanitation facilities is often discharged untreated into the environment, leading to significant insults to environmental and human health. Anaerobic digestion offers an attractive pathway for FS treatment with the concomitant production of energy in the form of methane. Another innovative option includes separating digestion into acidogenesis (production of volatile fatty acids (VFA)) and methanogenesis (production of methane), which could ultimately facilitate the production of an array of biofuels and biochemicals from the VFA. This work describes the development, implementation and modeling based analysis of a novel multiphase anaerobic fermentation-digestion process aimed at FS treatment in Kumasi, Ghana.  Methods.  A pilot-scale anaerobic fermentation process was implemented at the Kumasi Metropolitan Assembly’s Oti Sanitary Landfill Site at Adanse Dompoase.  The process consisted of six 10 m reactors in series, which were inoculated with bovine rumen and fed with fecal sludge obtained from public toilets.  The performance of the fermentation process was characterized in terms of both aqueous and gaseous variables representing the conversion of influent organic carbon to VFA as well as CH 4.  Using the operating data, the first-ever process model for FS fermentation and digestion was developed and calibrated, based on the activated sludge model framework. Results and Conclusions.  This work represents one of the first systematic efforts at integrated FS characterization and process modeling to enable anaerobic fermentation and digestion of FS. It is shown that owing to pre-fermentation of FS in public septage holding tanks, one could employ significantly smaller digesters (lower capital costs) or increased loading capabilities for FS conversion to biogas or VFA. Further, using the first-ever calibrated process model for FS fermentation and digestion presented herein, we expect improved and more

Implementation and process analysis of pilot scale multi-phase anaerobic fermentation and digestion of faecal sludge in Ghana.

PubMed

Shih, Justin; Fanyin-Martin, Ato; Taher, Edris; Chandran, Kartik

2017-11-06

Background.  In Ghana, faecal sludge (FS) from on-site sanitation facilities is often discharged untreated into the environment, leading to significant insults to environmental and human health. Anaerobic digestion offers an attractive pathway for FS treatment with the concomitant production of energy in the form of methane. Another innovative option includes separating digestion into acidogenesis (production of volatile fatty acids (VFA)) and methanogenesis (production of methane), which could ultimately facilitate the production of an array of biofuels and biochemicals from the VFA. This work describes the development, implementation and modeling based analysis of a novel multiphase anaerobic fermentation-digestion process aimed at FS treatment in Kumasi, Ghana.  Methods.  A pilot-scale anaerobic fermentation process was implemented at the Kumasi Metropolitan Assembly's Oti Sanitary Landfill Site at Adanse Dompoase.  The process consisted of six 10 m reactors in series, which were inoculated with bovine rumen and fed with fecal sludge obtained from public toilets.  The performance of the fermentation process was characterized in terms of both aqueous and gaseous variables representing the conversion of influent organic carbon to VFA as well as CH 4 .  Using the operating data, the first-ever process model for FS fermentation and digestion was developed and calibrated, based on the activated sludge model framework. Results and Conclusions.  This work represents one of the first systematic efforts at integrated FS characterization and process modeling to enable anaerobic fermentation and digestion of FS. It is shown that owing to pre-fermentation of FS in public septage holding tanks, one could employ significantly smaller digesters (lower capital costs) or increased loading capabilities for FS conversion to biogas or VFA. Further, using the first-ever calibrated process model for FS fermentation and digestion presented herein, we expect improved and more

Influence of fluid dynamics on anaerobic digestion of food waste for biogas production.

PubMed

Wang, Fengping; Zhang, Cunsheng; Huo, Shuhao

2017-05-01

To enhance the stability and efficiency of an anaerobic process, the influences of fluid dynamics on the performance of anaerobic digestion and sludge granulation were investigated using computational fluid dynamics (CFD). Four different propeller speeds (20, 60, 100, 140 r/min) were adopted for anaerobic digestion of food waste in a 30 L continuously stirred tank reactor (CSTR). Experimental results indicated that the methane yield increased with increasing the propeller speed within the experimental range. Results from CFD simulation and sludge granulation showed that the optimum propeller speed for anaerobic digestion was 100 r/min. Lower propeller speed (20 r/min) inhibited mass transfer and resulted in the failure of anaerobic digestion, while higher propeller speed (140 r/min) would lead to higher energy loss and system instability. Under this condition, anaerobic digestion could work effectively with higher efficiency of mass transfer which facilitated sludge granulation and biogas production. The corresponding mean liquid velocity and shear strain rate were 0.082 m/s and 10.48 s -1 , respectively. Moreover, compact granular sludge could be formed, with lower energy consumption. CFD was successfully used to study the influence of fluid dynamics on the anaerobic digestion process. The key parameters of the optimum mixing condition for anaerobic digestion of food waste in a 30 L CSTR including liquid velocity and shear strain rate were obtained using CFD, which were of paramount significance for the scale-up of the bioreactor. This study provided a new way for the optimization and scale-up of the anaerobic digestion process in CSTR based on the fluid dynamics analysis.

Bacterial community structure of a lab-scale anammox membrane bioreactor.

PubMed

Gonzalez-Martinez, Alejandro; Osorio, F; Rodriguez-Sanchez, Alejandro; Martinez-Toledo, Maria Victoria; Gonzalez-Lopez, Jesus; Lotti, Tommaso; van Loosdrecht, M C M

2015-01-01

Autotrophic nitrogen removal technologies have proliferated through the last decade. Among these, a promising one is the membrane bioreactor (MBR) Anammox, which can achieve very high solids retention time and therefore sets a proper environment for the cultivation of anammox bacteria. In this sense, the MBR Anammox is an efficient technology for the treatment of effluents with low organic carbon and high ammonium concentrations once it has been treated under partial nitrification systems. A lab-scale MBR Anammox bioreactor has been built at the Technological University of Delft, The Netherlands and has been proven for efficient nitrogen removal and efficient cultivation of anammox bacteria. In this study, next-generation sequencing techniques have been used for the investigation of the bacterial communities of this MBR Anammox for the first time ever. A strong domination of Candidatus Brocadia bacterium and also the presence of a myriad of other microorganisms that have adapted to this environment were detected, suggesting that the MBR Anammox bioreactor might have a more complex microbial ecosystem that it has been thought. Among these, nitrate-reducing heterotrophs and primary producers, among others, were identified. Definition of the ecological roles of the OTUs identified through metagenomic analysis was discussed. © 2014 American Institute of Chemical Engineers.

Biohydrogen production and wastewater treatment from organic wastewater by anaerobic fermentation with UASB

NASA Astrophysics Data System (ADS)

Wang, Lu; Li, Yong-feng; Wang, Yi-xuan; Yang, Chuan-ping

2010-11-01

In order to discuss the ability of H2-production and wastewater treatment, an up-flow anaerobic sludge bed (UASB) using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, hydrogen producing rate, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the biomass of inoculants was 22.5 g SSṡL-1 and the influent concentration, hydraulic retention time (HRT) and initial pH were within the ranges of 4000˜6000 mg CODṡL-1, 8 h and 5-5.5, respectively, and the biohydrogen producing reactor could work effectively. The maximum hydrogen production rate is 5.98 Lṡd-1. Simultaneously, the concentration of ethanol and acetic acid is around 80% of the aqueous terminal production in the system, which presents the typical ethanol type fermentation. pH is at the range of 4˜4.5 during the whole performing process, however, the removal rate of COD is just about 20%. Therefore, it's still needs further research to successfully achieve the biohydrogen production and wastewater treatment, simultaneously.

Love the Lab, Hate the Lab Report?

ERIC Educational Resources Information Center

Bjorn, Genevive

2018-01-01

In the author's large, urban high school, enrollment in a laboratory science is mandatory. While the student participation rate for lab activities is over 98%, the turn-in rate for traditional lab reports averages just 35% to 85%. Those students who don't produce a lab report miss a critical opportunity to improve their skills in scientific…

Advanced anaerobic bioconversion of lignocellulosic waste for the melissa life support system

NASA Astrophysics Data System (ADS)

Lissens, G.; Verstraete, W.; Albrecht, T.; Brunner, G.; Creuly, C.; Dussap, G.; Kube, J.; Maerkl, H.; Lasseur, C.

The feasibility of nearly-complete conversion of lignocellulosic waste (70% food crops, 20% faecal matter and 10% green algae) into biogas was investigated in the context of the MELiSSA loop (Micro-Ecological Life Support System Alternative). The treatment comprised a series of processes, i.e. a mesophilic laboratory scale CSTR (continuously stirred tank reactor), an upflow biofilm reactor, a fiber liquefaction reactor employing the rumen bacterium Fibrobacter succinogenes and a hydrothermolysis system in near-critical water. By the one-stage CSTR, a biogas yield of 75% with a specific biogas production of 0.37 l biogas g-1 VSS (volatile suspended solids) added at a RT (hydraulic retention time) of 20-25 d was obtained. Biogas yields could not be increased considerably at higher RT, indicating the depletion of readily available substrate after 25 d. The solids present in the CSTR-effluent were subsequently treated in two ways. Hydrothermal treatment (T ˜ 310-350C, p ˜ 240 bar) resulted in effective carbon liquefaction (50-60% without and 83% with carbon dioxide saturation) and complete sanitation of the residue. Application of the cellulolytic Fibrobacter succinogenes converted remaining cellulose contained in the CSTR-effluent into acetate and propionate mainly. Subsequent anaerobic digestion of the hydrothermolysis and the Fibrobacter hydrolysates allowed conversion of 48-60% and 30%, respectively. Thus, the total process yielded biogas corresponding with conversions up to 90% of the original organic matter. It appears that particularly mesophilic digestion in conjunction with hydrothermolysis offers interesting features for (nearly) the MELiSSA system. The described additional technologies show that complete and hygienic carbon and energy recovery from human waste within MELiSSA is technically feasible, provided that the extra energy needed for the thermal treatment is guaranteed.

University of Wisconsin Oshkosh Anaerobic Dry Digestion Facility

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

Koker, John; Lizotte, Michael

The University of Wisconsin Oshkosh Anaerobic Dry Digestion Facility is a demonstration project that supported the first commercial-scale use in the United States of high solids, static pile technology for anaerobic digestion of organic waste to generate biogas for use in generating electricity and heat. The research adds to the understanding of startup, operation and supply chain issues for anaerobic digester technology. Issues and performance were documented for equipment installation and modifications, feedstock availability and quality, weekly loading and unloading of digestion chambers, chemical composition of biogas produced, and energy production. This facility also demonstrated an urban industrial ecology approachmore » to siting such facilities near sewage treatment plants (to capture and use excess biogas generated by the plants) and organic yard waste collection sites (a source of feedstock).« less

The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC) Treatment by 454-Pyrosequencing.

PubMed

Wei, Chao; He, Wenjie; Wei, Li; Li, Chunying; Ma, Jun

2015-01-01

In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O) integrated process for the treatment of petrochemical nanofiltration concentrate (NFC) wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A) and aerobic biofilm (Sample O), 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH) biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB) Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN) on average were 90.51% and 75.11% during the entire treatment process.

The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC) Treatment by 454-Pyrosequencing

PubMed Central

Wei, Chao; He, Wenjie; Wei, Li; Li, Chunying; Ma, Jun

2015-01-01

In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O) integrated process for the treatment of petrochemical nanofiltration concentrate (NFC) wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A) and aerobic biofilm (Sample O), 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH) biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB) Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC) removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN) on average were 90.51% and 75.11% during the entire treatment process. PMID:26461260

Analysis of up-flow aerated biological activated carbon filter technology in drinking water treatment.

PubMed

Lu, Shaoming; Liu, Jincui; Li, Shaowen; Biney, Elizabeth

2013-01-01

Problems have been found in the traditional post-positioned down-flow biological activated carbon filter (DBACF), such as microorganism leakage and low biodegradability. A pilot test was carried out to place a BACF between the sediment tank and the sand filter; a new technology of dual media up-flow aerated biological activated carbon filter (UBACF) was developed. Results showed that in terms of the new process, the up-flow mode was better than the down-flow. Compared with the DBACF, the problem of microorganism leakage could be well resolved with the UBACF process by adding disinfectant before the sand filtration, and a similar adsorption effect could be obtained. For the tested raw water, the COD(Mn) and NH3-N removal rate was 54.6% and 85.0%, respectively, similar to the waterworks with the DBACF process. The UBACF greatly enhanced oxygen supply capability and mass transfer rate via aeration, and the NH3-N removal ability was significantly improved from 1.5 mg/L to more than 3 mg/L. Influent to the UBACF with higher turbidity could be coped with through the primary filtration of the ceramisite layer combined with fluid-bed technology, which gave the carbon bed a low-turbidity environment of less than 1.0 NTU. The backwashing parameters and carbon abrasion rate of the two processes were almost the same.

Comparison of start-up strategies and process performance during semi-continuous anaerobic digestion of sugarcane filter cake co-digested with bagasse.

PubMed

Janke, Leandro; Leite, Athaydes F; Nikolausz, Marcell; Radetski, Claudemir M; Nelles, Michael; Stinner, Walter

2016-02-01

The anaerobic digestion of sugarcane filter cake and the option of co-digestion with bagasse were investigated in a semi-continuous feeding regime to assess the main parameters used for large-scale process designing. Moreover, fresh cattle manure was considered as alternative inoculum for the start-up of biogas reactors in cases where digestate from a biogas plant would not be available in remote rural areas. Experiments were carried out in 6 lab-scale semi-continuous stirred-tank reactors at mesophilic conditions (38±1°C) while the main anaerobic digestion process parameters monitored. Fresh cattle manure demonstrated to be appropriate for the start-up process. However, an acclimation period was required due to the high initial volatile fatty acids concentration (8.5gL(-1)). Regardless the mono-digestion of filter cake presented 50% higher biogas yield (480mLgVS(-1)) than co-digestion with bagasse (320mLgVS(-1)) during steady state conditions. A large-scale co-digestion system would produce 58% more biogas (1008m(3)h(-1)) than mono-digestion of filter cake (634m(3)h(-1)) due to its higher biomass availability for biogas conversion. Considering that the biogas production rate was the technical parameter that displayed the most relevant differences between the analyzed substrate options (0.99-1.45m(3)biogasm(3)d(-1)). The decision of which substrate option should be implemented in practice would be mainly driven by the available construction techniques, since economically efficient tanks could compensate the lower biogas production rate of co-digestion option. Copyright © 2015 Elsevier Ltd. All rights reserved.

Anaerobic bioconversion of organic waste into biogas by hot water treatment at near-critical conditions: application in bioregenerative life support.

PubMed

Lissens, Geert; Verstraete, Willy; Albrecht, Tobias; Brunner, Gerd; Lasseur, Christophe

2003-01-01

The feasibility of nearly-complete conversion of lignocellulosic waste (70% food crops, 20% faecal matter and 10% green algae) into biogas was investigated in the context of a Life Support Project. The treatment comprised a series of processes, i.e. a mesophilic laboratory scale CSTR (continuously stirred tank reactor), an upflow biofilm reactor and a hydrothermolysis system in near-critical water. By the one-stage CSTR, a biogas yield of 75% with a specific biogas production of 0.37 l biogas g(-1) VSS (volatile suspended solids) added at a HRT (hydraulic retention time) of 20 d was obtained. Biogas yields further increased with 10-15% at HRT > 20 d, indicating the hydrolysis of lignocellulose to be the rate-limiting conversion step. The solids present in the CSTR-effluent were subsequently treated by hot water treatment (T approximately 310-350 degrees C, p approximately 240 bar), resulting in effective carbon liquefaction (50-60% without and 83% with carbon dioxide saturation) and complete hygienisation of the residue. Subsequent anaerobic digestion of the hydrolysate allowed further conversion of 48-60% on COD (chemical oxygen demand) basis. Thus, the total process yielded biogas corresponding with a COD conversion up to 90% of the original organic matter. It appears that mesophilic digestion in conjunction with hydrothermolysis at near-critical conditions offers interesting features for (nearly) complete, non-toxic and hygienic carbon and energy recovery from human waste in a bioregenerative life support context.

Quantitative investigation of hydraulic mixing energy input during batch mode anaerobic digestion and its impact on performance.

PubMed

McLeod, James; Othman, Maazuza Z; Parthasarathy, Rajarathinam

2018-05-26

The relationship between mixing energy input and biogas production was investigated by anaerobically digesting sewage sludge in lab scale, hydraulically mixed, batch mode digesters at six different specific energy inputs. The goal was to identify how mixing energy influenced digestion performance at quantitative levels to help explain the varying results in other published works. The results showed that digester homogeneity was largely uninfluenced by energy input, whereas cumulative biogas production and solids destruction were. With similar solids distributions between conditions, the observed differences were attributed to shear forces disrupting substrate-microbe flocs rather than the formation of temperature and/or concentration gradients. Disruption of the substrate-microbe flocs produced less favourable conditions for hydrolytic bacteria, resulting in less production of biomass and more biogas. Overall, this hypothesis explains the current body of research including the inhibitory conditions reported at extreme mixing power inputs. However, further work is required to definitively prove it. Copyright © 2018 Elsevier Ltd. All rights reserved.

Production of biogas from solid organic wastes through anaerobic digestion: a review.

PubMed

Muhammad Nasir, Ismail; Mohd Ghazi, Tinia I; Omar, Rozita

2012-07-01

Anaerobic digestion treatments have often been used for biological stabilization of solid wastes. These treatment processes generate biogas which can be used as a renewable energy sources. Recently, anaerobic digestion of solid wastes has attracted more interest because of current environmental problems, most especially those concerned with global warming. Thus, laboratory-scale research on this area has increased significantly. In this review paper, the summary of the most recent research activities covering production of biogas from solid wastes according to its origin via various anaerobic technologies was presented.

Lab experiments investigating astrophysical jet physics

NASA Astrophysics Data System (ADS)

Bellan, Paul

2014-10-01

Dynamics relevant to astrophysical plasmas is being investigated in lab experiments having similar physics and topology, but much smaller time and space scales. High speed movies and numerical simulations both show that highly collimated MHD-driven plasma flows are a critical feature; these collimated flows can be considered to be a lab version of an astrophysical jet. Having both axial and azimuthal magnetic fields, the jet is effectively an axially lengthening plasma-confining flux tube with embedded helical magnetic field (flux rope). The jet velocity is in good agreement with an MHD acceleration model. Axial stagnation of the jet compresses embedded azimuthal magnetic flux and so results in jet self-collimation. Jets kink when they breach the Kruskal-Shafranov stability limit. The lateral acceleration of a sufficiently strong kink can provide an effective gravity which provides the environment for a spontaneously-developing, fine-scale, extremely fast Rayleigh-Taylor instability that erodes the current channel to be smaller than the ion skin depth. This cascade from the ideal MHD scale of the kink to the non-MHD ion skin depth scale can result in a fast magnetic reconnection whereby the jet breaks off from its source electrode. Supported by USDOE and NSF.

Comparison of Leachate Quality from Aerobic and Anaerobic Municipal Solid Waste Bioreactors

NASA Astrophysics Data System (ADS)

Borglin, S. E.; Hazen, T. C.; Oldenburg, C. M.

2002-12-01

Municipal solid waste landfills are becoming a drain on the resources of local municipalities as the requirements for stabilization and containment become increasingly stringent. Current regulations limit the moisture in the landfill to minimize leachate production and lower the potential for release of leachate to the environment. Recent research has shown that addition and recycling of moisture in the waste optimizes the biodegradation of stabilization and also provides a means for leachate treatment. This study compares the characteristics of leachate produced from aerobic and anaerobic laboratory bioreactors, and leachate collected from a full-scale anaerobic bioreactor. The laboratory reactors consisted of 200-liter tanks filled with fresh waste materials with the following conditions: (a) aerobic (air injection with leachate recirculation), (b) anaerobic (leachate recirculation). The leachate from the reactors was monitored for metals, nutrients, organic carbon, and microbiological activity for up to 500 days. Leachate from the aerobic tank had significantly lower concentrations of all potential contaminants, both organic and metal, after only a few weeks of operation. Metals leaching was low throughout the test period for the aerobic tanks, and decreased over time for the anaerobic tanks. Organic carbon as measured by BOD, COD, TOC, and COD were an order of magnitude higher in the leachate from the anaerobic system. Microbiological assessment by lipid analysis, enzyme activity assays, and cell counts showed high biomass and diversity in both the aerobic and anaerobic bioreactors, with higher activity in the anaerobic leachate. Results from the full-scale anaerobic bioreactor were not significantly different from those of the laboratory anaerobic bioreactor. The reduction in noxious odors was a significant advantage of the aerobic system. These results suggest that aerobic management of landfills could reduce or eliminate the need for leachate treatment

Modeling Lab-sized Anaerobic Fluidized Bed Reactor (AFBR) for Palm Oil Mill Effluent (POME) treatment: from Batch to Continuous Reactors

NASA Astrophysics Data System (ADS)

Mufti Azis, Muhammad; Sudibyo, Hanifrahmawan; Budhijanto, Wiratni

2018-03-01

Indonesia is aiming to produce 30 million tones/year of crude palm oil (CPO) by 2020. As a result, 90 million tones/year of POME will be produced. POME is highly polluting wastewater which may cause severe environmental problem due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Due to the limitation of open pond treatment, the use of AFBR has been considered as a potential technology to treat POME. This study aims to develop mathematical models of lab-sized Anaerobic Fluidized Bed Reactor (AFBR) in batch and continuous processes. In addition, the AFBR also utilized natural zeolite as an immobilized media for microbes. To initiate the biomass growth, biodiesel waste has been used as an inoculum. In the first part of this study, a batch AFBR was operated to evaluate the COD, VFA, and CH4 concentrations. By comparing the batch results with and without zeolite, it showed that the addition of 17 g/gSCOD zeolite gave larger COD decrease within 20 days of operation. In order to elucidate the mechanism, parameter estimations of 12 kinetic parameters were proposed to describe the batch reactor performance. The model in general could describe the batch experimental data well. In the second part of this study, the kinetic parameters obtained from batch reactor were used to simulate the performance of double column AFBR where the acidogenic and methanogenic biomass were separated. The simulation showed that a relatively long residence time (Hydraulic Residence Time, HRT) was required to treat POME using the proposed double column AFBR. Sensitivity analyses was conducted and revealed that μm1 appeared to be the most sensitive parameter to reduce the HRT of double column AFBR.

Enhancement of the anaerobic hydrolysis and fermentation of municipal solid waste in leachbed reactors by varying flow direction during water addition and leachate recycle

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

Uke, Matthew N., E-mail: cnmnu@leeds.ac.uk; Stentiford, Edward

2013-06-15

Highlights: ► Combined downflow and upflow water addition improved hydraulic conductivity. ► Upflow water addition unclogged perforated screen leading to more leachate flow. ► The volume of water added and transmitted positively correlated with hydrolysis process. ► Combined downflow and upflow water addition increased COD production and yield. ► Combined downflow and upflow leachate recycle improved leachate and COD production. - Abstract: Poor performance of leachbed reactors (LBRs) is attributed to channelling, compaction from waste loading, unidirectional water addition and leachate flow causing reduced hydraulic conductivity and leachate flow blockage. Performance enhancement was evaluated in three LBRs M, D andmore » U at 22 ± 3 °C using three water addition and leachate recycle strategies; water addition was downflow in D throughout, intermittently upflow and downflow in M and U with 77% volume downflow in M, 54% volume downflow in U while the rest were upflow. Leachate recycle was downflow in D, alternately downflow and upflow in M and upflow in U. The strategy adopted in U led to more water addition (30.3%), leachate production (33%) and chemical oxygen demand (COD) solubilisation (33%; 1609 g against 1210 g) compared to D (control). The total and volatile solids (TS and VS) reductions were similar but the highest COD yield (g-COD/g-TS and g-COD/g-VS removed) was in U (1.6 and 1.9); the values were 1.33 and 1.57 for M, and 1.18 and 1.41 for D respectively. The strategy adopted in U showed superior performance with more COD and leachate production compared to reactors M and D.« less

Application of molecular techniques to evaluate the methanogenic archaea and anaerobic bacteria in the presence of oxygen with different COD:sulfate ratios in a UASB reactor.

PubMed

Hirasawa, Julia Sumiko; Sarti, Arnaldo; Del Aguila, Nora Katia Saavedra; Varesche, Maria Bernadete A

2008-10-01

In this paper, the microbial characteristics of the granular sludge in the presence of oxygen (3.0+/-0.7 mg O2 l(-1)) were analyzed using molecular biology techniques. The granules were provided by an upflow anaerobic sludge blanket (UASB) operated over 469 days and fed with synthetic substrate. Ethanol and sulfate were added to obtain different COD/SO4(2-) ratios (3.0, 2.0, and 1.6). The results of fluorescent in situ hybridization (FISH) analyses showed that archaeal cells, detected by the ARC915 probe, accounted for 77%, 84%, and 75% in the COD/SO(4)(2-) ratios (3.0, 2.0, and 1.6, respectively). Methanosaeta sp. was the predominant acetoclastic archaea observed by optical microscopy and FISH analyses, and confirmed by sequencing of the excised bands of the DGGE gel with a similarity of 96%. The sulfate-reducing bacterium Desulfovibrio vulgaris subsp. vulgaris (similarity of 99%) was verified by sequencing of the DGGE band. Others identified microorganism were similar to Shewanella sp. and Desulfitobacterium hafniense, with similarities of 95% and 99%, respectively. These results confirmed that the presence of oxygen did not severely affect the metabolism of microorganisms that are commonly considered strictly anaerobic. We obtained mean efficiencies of organic matter conversion and sulfate reducing higher than 74%.

High-pressure anaerobic digestion up to 100 bar: influence of initial pressure on production kinetics and specific methane yields.

PubMed

Merkle, Wolfgang; Baer, Katharina; Haag, Nicola Leonard; Zielonka, Simon; Ortloff, Felix; Graf, Frank; Lemmer, Andreas

2017-02-01

To ensure an efficient use of biogas produced by anaerobic digestion, in some cases it would be advisable to upgrade the biogenic gases and inject them into the transnational gas grids. To investigate biogas production under high-pressure conditions up to 100 bar, new pressure batch methane reactors were developed for preliminary lab-scale experiments with a mixture of grass and maize silage hydrolysate. During this investigation, the effects of different initial pressures (1, 50 and 100 bar) on pressure increase, gas production and the specific methane yield using nitrogen as inert gas were determined. Based on the experimental findings increasing initial pressures alter neither significantly, further pressure increases nor pressure increase rates. All supplied organic acids were degraded and no measurable inhibition of the microorganisms was observed. The results show that methane reactors can be operated at operating pressures up to 100 bar without any negative effects on methane production.

Integrated anaerobic/aerobic biological treatment for intensive swine production.

PubMed

Bortone, Giuseppe

2009-11-01

Manure processing could help farmers to effectively manage nitrogen (N) surplus load. Many pig farms have to treat wastewater. Piggery wastewater treatment is a complex challenge, due to the high COD and N concentrations and low C/N ratio. Anaerobic digestion (AD) could be a convenient pre-treatment, particularly from the energetic view point and farm income, but this causes further reduction of C/N ratio and makes denitrification difficult. N removal can only be obtained integrating anaerobic/aerobic treatment by taking into account the best use of electron donors. Experiences gained in Italy during development of integrated biological treatment approaches for swine manure, from bench to full scale, are reported in this paper. Solid/liquid separation as pre-treatment of raw manure is an efficient strategy to facilitate liquid fraction treatment without significantly lowering C/N ratio. In Italy, two full scale SBRs showed excellent efficiency and reliability. Current renewable energy policy and incentives makes economically attractive the application of AD to the separated solid fraction using high solid anaerobic digester (HSAD) technology. Economic evaluation showed that energy production can reduce costs up to 60%, making sustainable the overall treatment.

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...

Anaerobic Digestion of Laminaria japonica Waste from Industrial Production Residues in Laboratory- and Pilot-Scale.

PubMed

Barbot, Yann Nicolas; Thomsen, Claudia; Thomsen, Laurenz; Benz, Roland

2015-09-18

The cultivation of macroalgae to supply the biofuel, pharmaceutical or food industries generates a considerable amount of organic residue, which represents a potential substrate for biomethanation. Its use optimizes the total resource exploitation by the simultaneous disposal of waste biomaterials. In this study, we explored the biochemical methane potential (BMP) and biomethane recovery of industrial Laminaria japonica waste (LJW) in batch, continuous laboratory and pilot-scale trials. Thermo-acidic pretreatment with industry-grade HCl or industrial flue gas condensate (FGC), as well as a co-digestion approach with maize silage (MS) did not improve the biomethane recovery. BMPs between 172 mL and 214 mL g(-1) volatile solids (VS) were recorded. We proved the feasibility of long-term continuous anaerobic digestion with LJW as sole feedstock showing a steady biomethane production rate of 173 mL g(-1) VS. The quality of fermentation residue was sufficient to serve as biofertilizer, with enriched amounts of potassium, sulfur and iron. We further demonstrated the upscaling feasibility of the process in a pilot-scale system where a CH₄ recovery of 189 L kg(-1) VS was achieved and a biogas composition of 55% CH₄ and 38% CO₂ was recorded.

Hydroponic system for the treatment of anaerobic liquid.

PubMed

Krishnasamy, K; Nair, J; Bäuml, B

2012-01-01

The effluent from anaerobic digestion process has high concentrations of nutrients, particularly nitrogen, essential for plant growth but is not suitable for direct disposal or application due to high chemical oxygen demand (COD), low dissolved oxygen (DO), odour issues and is potentially phytotoxic. This research explored the optimum conditions of anaerobic effluent for application and dilutions of the effluent required to obtain better plant growth. A small-scale hydroponic system was constructed in a glasshouse to test different concentrations of anaerobic effluent against a commercial hydroponic medium as the control for the growth of silverbeet. It was found that the survival of silverbeet was negatively affected at 50% concentration due to low DO and NH(4) toxicity. The concentration of 20% anaerobic liquid was found to be the most efficient with highest foliage yield and plant growth. The hydroponic system with 20% concentrated effluent had better utilisation of nutrients for plant growth and a COD reduction of 95% was achieved during the 50-day growth period. This preliminary evaluation revealed that the growth and development of silverbeet was significantly lower in anaerobic effluent compared with a commercial hydroponic plant growth solution. The nutrient quality of anaerobic effluent could be highly variable with the process and the waste material used and dilution may depend on the nutrient content of the effluent. It is recommended that, a pre-treatment of the effluent to increase DO and reduce ammonium content is required before plant application, and simple dilution by itself is not suitable for optimum plant growth in a hydroponic system.

Implementation of in-line infrared monitor in full-scale anaerobic digestion process.

PubMed

Spanjers, H; Bouvier, J C; Steenweg, P; Bisschops, I; van Gils, W; Versprille, B

2006-01-01

During start up but also during normal operation, anaerobic reactor systems should be run and monitored carefully to secure trouble-free operation, because the process is vulnerable to disturbances such as temporary overloading, biomass wash out and influent toxicity. The present method of monitoring is usually by manual sampling and subsequent laboratory analysis. Data collection, processing and feedback to system operation is manual and ad hoc, and involves high-level operator skills and attention. As a result, systems tend to be designed at relatively conservative design loading rates resulting in significant over-sizing of reactors and thus increased systems cost. It is therefore desirable to have on-line and continuous access to performance data on influent and effluent quality. Relevant variables to indicate process performance include VFA, COD, alkalinity, sulphate, and, if aerobic post-treatment is considered, total nitrogen, ammonia and nitrate. Recently, mid-IR spectrometry was demonstrated on a pilot scale to be suitable for in-line simultaneous measurement of these variables. This paper describes a full-scale application of the technique to test its ability to monitor continuously and without human intervention the above variables simultaneously in two process streams. For VFA, COD, sulphate, ammonium and TKN good agreement was obtained between in-line and manual measurements. During a period of six months the in-line measurements had to be interrupted several times because of clogging. It appeared that the sample pre-treatment unit was not able to cope with high solids concentrations all the time.

Biomethanation of Syngas Using Anaerobic Sludge: Shift in the Catabolic Routes with the CO Partial Pressure Increase.

PubMed

Sancho Navarro, Silvia; Cimpoia, Ruxandra; Bruant, Guillaume; Guiot, Serge R

2016-01-01

Syngas generated by thermal gasification of biomass or coal can be steam reformed and purified into methane, which could be used locally for energy needs, or re-injected in the natural gas grid. As an alternative to chemical catalysis, the main components of the syngas (CO, CO2, and H2) can be used as substrates by a wide range of microorganisms, to be converted into gas biofuels, including methane. This study evaluates the carboxydotrophic (CO-consuming) methanogenic potential present in an anaerobic sludge from an upflow anaerobic sludge bed (UASB) reactor treating waste water, and elucidates the CO conversion routes to methane at 35 ± 3°C. Kinetic activity tests under CO at partial pressures (pCO) varying from 0.1 to 1.5 atm (0.09-1.31 mmol/L in the liquid phase) showed a significant carboxydotrophic activity potential for growing conditions on CO alone. A maximum methanogenic activity of 1 mmol CH4 per g of volatile suspended solid and per day was achieved at 0.2 atm of CO (0.17 mmol/L), and then the rate decreased with the amount of CO supplied. The intermediary metabolites such as acetate, H2, and propionate started to accumulate at higher CO concentrations. Inhibition experiments with 2-bromoethanesulfonic acid (BES), fluoroacetate, and vancomycin showed that in a mixed culture CO was converted mainly to acetate by acetogenic bacteria, which was further transformed to methane by acetoclastic methanogens, while direct methanogenic CO conversion was negligible. Methanogenesis was totally blocked at high pCO in the bottles (≥1 atm). However it was possible to achieve higher methanogenic potential under a 100% CO atmosphere after acclimation of the sludge to CO. This adaptation to high CO concentrations led to a shift in the archaeal population, then dominated by hydrogen-utilizing methanogens, which were able to take over acetoclastic methanogens, while syntrophic acetate oxidizing (SAO) bacteria oxidized acetate into CO2 and H2. The disaggregation of the

Biomethanation of Syngas Using Anaerobic Sludge: Shift in the Catabolic Routes with the CO Partial Pressure Increase

PubMed Central

Sancho Navarro, Silvia; Cimpoia, Ruxandra; Bruant, Guillaume; Guiot, Serge R.

2016-01-01

Syngas generated by thermal gasification of biomass or coal can be steam reformed and purified into methane, which could be used locally for energy needs, or re-injected in the natural gas grid. As an alternative to chemical catalysis, the main components of the syngas (CO, CO2, and H2) can be used as substrates by a wide range of microorganisms, to be converted into gas biofuels, including methane. This study evaluates the carboxydotrophic (CO-consuming) methanogenic potential present in an anaerobic sludge from an upflow anaerobic sludge bed (UASB) reactor treating waste water, and elucidates the CO conversion routes to methane at 35 ± 3°C. Kinetic activity tests under CO at partial pressures (pCO) varying from 0.1 to 1.5 atm (0.09–1.31 mmol/L in the liquid phase) showed a significant carboxydotrophic activity potential for growing conditions on CO alone. A maximum methanogenic activity of 1 mmol CH4 per g of volatile suspended solid and per day was achieved at 0.2 atm of CO (0.17 mmol/L), and then the rate decreased with the amount of CO supplied. The intermediary metabolites such as acetate, H2, and propionate started to accumulate at higher CO concentrations. Inhibition experiments with 2-bromoethanesulfonic acid (BES), fluoroacetate, and vancomycin showed that in a mixed culture CO was converted mainly to acetate by acetogenic bacteria, which was further transformed to methane by acetoclastic methanogens, while direct methanogenic CO conversion was negligible. Methanogenesis was totally blocked at high pCO in the bottles (≥1 atm). However it was possible to achieve higher methanogenic potential under a 100% CO atmosphere after acclimation of the sludge to CO. This adaptation to high CO concentrations led to a shift in the archaeal population, then dominated by hydrogen-utilizing methanogens, which were able to take over acetoclastic methanogens, while syntrophic acetate oxidizing (SAO) bacteria oxidized acetate into CO2 and H2. The disaggregation of the

Anaerobic bacteria

MedlinePlus

Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Brook I. Diseases caused by non-spore-forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

Start-up of simultaneous removal of ammonium and sulfate from an anaerobic ammonium oxidation (anammox) process in an anaerobic up-flow bioreactor.

PubMed

Yang, Zhiquan; Zhou, Shaoqi; Sun, Yanbo

2009-09-30

A laboratory testing of simultaneous removal of ammonium and sulfate (SRAS) was studied from an anammox process in an anaerobic bioreactor filled with granular activated carbon. Two different phases of experiment were investigated to start up the SRAS process, and final batch tests were performed to analyze the SRAS process. The experiment included an anammox process and an SRAS process. During the anammox process, the highest removal efficiency of ammonium and nitrite was up to 97 and 98%, respectively. After 160 days in the stationary phase of anammox process, the ratio of ammonium to nitrite consumption was approximately 1:1.15, which is much higher than 1:1.32 in the traditional anammox process. The extra electron acceptor, such as sulfate, was thought to react with ammonium by bacteria. Synthetic wastewater containing ammonium chlorine and sodium sulfate was used as the feed for the bioreactor in the second phase of experiment. During the SRAS process, the influent concentrations of ammonium and sulfate were controlled to be 50-60 and 210-240 mg L(-1) respectively. After start-up and acclimatization of this process for 60 days, the average effluent concentrations of ammonium and sulfate were 30 and 160 mg L(-1), respectively. The simultaneous ammonium and sulfate removal was detected in the reactor. In order to further validate the biochemical interaction between ammonium and sulfate, batch tests was carried out. Abiotic tests were carried out to demonstrate that the pure chemical action between ammonium and sulfate without microorganism was not possible. Biotic assays with different ammonium and sulfate concentrations were further investigated that high concentrations of ammonium and sulfate could promote simultaneous removal of ammonium and sulfate. And elemental sulfur and nitrogen gas as the products measured in the SRAS process helped to demonstrate the occurrence of new interaction between nitrogen and sulfur. The new process of SRAS in the inorganic

Devolatilization of oil sludge in a lab-scale bubbling fluidized bed.

PubMed

Liu, Jianguo; Jiang, Xiumin; Han, Xiangxin

2011-01-30

Devolatilization of oil sludge pellets was investigated in nitrogen and air atmosphere in a lab-scale bubbling fluidized bed (BFB). Devolatilization times were measured by the degree of completion of the evolution of the volatiles for individual oil sludge pellets in the 5-15 mm diameter range. The influences of pellet size, bed temperature and superficial fluidization velocity on devolatilization time were evaluated. The variation of devolatilization time with particle diameter was expressed by the correlation, τ(d) = Ad(p)(N). The devolatilization time to pellet diameter curve shows nearly a linear increase in nitrogen, whereas an exponential increase in air. No noticeable effect of superficial fluidization velocity on devolatilization time in air atmosphere was observed. The behavior of the sludge pellets in the BFB was also focused during combustion experiments, primary fragmentation (a micro-explosive combustion phenomenon) was observed for bigger pellets (>10mm) at high bed temperatures (>700 °C), which occurred towards the end of combustion and remarkably reduce the devolatilization time of the oil sludge pellet. The size analysis of bed materials and fly ash showed that entire ash particle was entrained or elutriated out of the BFB furnace due to the fragile structure of oil sludge ash particles. Copyright © 2010 Elsevier B.V. All rights reserved.

Comparison of simple, small, full-scale sewage treatment systems in Brazil: UASB-maturation ponds-coarse filter; UASB-horizontal subsurface-flow wetland; vertical-flow wetland (first stage of French system).

PubMed

von Sperling, M

2015-01-01

This paper presents a comparison between three simple sewage treatment lines involving natural processes: (a) upflow anaerobic sludge blanket (UASB) reactor-three maturation ponds in series-coarse rock filter; (b) UASB reactor-horizontal subsurface-flow constructed wetland; and (c) vertical-flow constructed wetlands treating raw sewage (first stage of the French system). The evaluation was based on several years of practical experience with three small full-scale plants receiving the same influent wastewater (population equivalents of 220, 60 and 100 inhabitants) in the city of Belo Horizonte, Brazil. The comparison included interpretation of concentrations and removal efficiencies based on monitoring data (organic matter, solids, nitrogen, phosphorus, coliforms and helminth eggs), together with an evaluation of practical aspects, such as land and volume requirements, sludge production and handling, plant management, clogging and others. Based on an integrated evaluation of all aspects involved, it is worth emphasizing that each system has its own specificities, and no generalization can be made on the best option. The overall conclusion is that the three lines are suitable for sewage treatment in small communities in warm-climate regions.

A comparison of the technological effectiveness of dairy wastewater treatment in anaerobic UASB reactor and anaerobic reactor with an innovative design.

PubMed

Jedrzejewska-Cicinska, M; Kozak, K; Krzemieniewski, M

2007-10-01

The present research was an investigation of the influence of an innovative design of reactor filled with polyethylene (PE) granulate on model dairy wastewater treatment efficiency under anaerobic conditions compared to that obtained in a typical UASB reactor. The experiment was conducted at laboratory scale. An innovative reactor was designed with the reaction chamber inclined 30 degrees in relation to the ground with upward waste flow and was filled with PE granular material. Raw model dairy wastewater was fed to two anaerobic reactors of different design at the organic loading rate of 4 kg COD m(-3)d(-1). Throughout the experiment, a higher removal efficiency of organic compounds was observed in the reactor with an innovative design and it was higher by 7.1% on average than in the UASB reactor. The total suspended solids was lower in the wastewater treated in the anaerobic reactor with the innovative design. Applying a PE granulated filling in the chamber of the innovative reactor contributed to an even distribution of sludge biomass in the reactor, reducing washout of anaerobic sludge biomass from the reaction chamber and giving a higher organic compounds removal efficiency.

Preservation of Ceriporiopsis subvermispora and Lentinula edodes treated wheat straw under anaerobic conditions.

PubMed

Mao, Lei; Sonnenberg, Anton S M; Hendriks, Wouter H; Cone, John W

2018-02-01

No attention has been paid so far to the preservation of fungal-treated lignocellulose for longer periods. In the present study, we treated wheat straw (WS) with the white-rot fungi Ceriporiopsis subvermispora and Lentinula edodes for 8 weeks and assessed changes in pH, chemical composition and in vitro gas production (IVGP) weekly. Fungal-treated WS was also stored for 64 days 'as is', with the addition of lactic acid bacteria (LAB) or with a combination of LAB and molasses in airtight glass jars mimicking ensiling conditions. Both fungi significantly reduced the lignin and hemicellulose content of WS, and increased the cellulose content. The IVGP increased with increasing time of incubation, indicating the increase in digestibility. Both fungi lowered the pH of WS under 4.3, which guarantees an initial and stable low pH during anaerobic storage. Minor changes in fibre composition and IVGP were observed for stored L. edodes treated WS, whereas no change occurred for C. subvermispora. It is possible to conserve C. subvermispora and L. edodes treated straw under anaerobic condition without additives up to 64 days. This finding is important for practical application to supply fungi-treated feed to ruminant animals for a prolonged period. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

INFLUENCE OF HYDRAULIC RETENTION TIME ON EXTENT OF PCE DECHLORINATION AND PRELIMINARY CHARACTERIZATION OF THE ENRICHMENT CULTURE. (R826694C703)

EPA Science Inventory

The extent of tetrachloroethene (PCE) dechlorination in two chemostats was evaluated as a function of hydraulic retention time (HRT). The inoculum of these chemostats was from an upflow anaerobic sludge blanket (UASB) reactor that rapidly converts PCE to vinyl chloride (VC) an...

Spatio-temporal variation of landfill gas in pilot-scale semi-aerobic and anaerobic landfills over 5years.

PubMed

Wu, Xiaohui; Yue, Bo; Huang, Qifei; Wang, Qi; Lin, Ye; Zhang, Wei; Yan, Zhuoyi

2017-04-01

Variation of CH 4 , CO 2 , and O 2 concentrations in layers of different depths in semi-aerobic and anaerobic landfills was analyzed over a period of 5years. The results showed that most of the municipal solid waste became basically stable after 5years of landfill disposal. In the upper and middle layer, the concentration of CH 4 in the semi-aerobic landfill was significantly lower than that in the anaerobic landfill in different landfill periods, while in the lower layer, there was little difference in the CH 4 concentration between the semi-aerobic and anaerobic landfills. The average concentration of CH 4 and CO 2 in the anaerobic landfill was always higher than that in the semi-aerobic landfill, while the O 2 concentration showed an opposite variation in different landfill periods. This was related to the aerobic reaction of landfill waste around the perforated pipe in the semi-aerobic landfill, which inhibited effective landfill gas generation. Copyright © 2016. Published by Elsevier B.V.

Potential application of anaerobic extremophiles for hydrogen production

NASA Astrophysics Data System (ADS)

Pikuta, Elena V.; Hoover, Richard B.

2004-11-01

In processes of the substrate fermentation most anaerobes produce molecular hydrogen as a waste end product, which often controls the culture growth as an inhibitor. Usually in nature the hydrogen is easily removed from an ecosystem, due to its physical features, and an immediate consumption by the secondary anaerobes that sometimes behave as competitors for electron donors; a classical example of this kind of substrate competition in anaerobic microbial communities is the interaction between methanogens and sulfate- or sulfur-reducers. Previously, on the mixed cultures of anaerobes at neutral pH, it was demonstrated that bacterial hydrogen production could provide a good alternative energy source. At neutral pH the original cultures could easily contaminated by methanogens, and the most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and furthermore, the cultivation with pathogenic contaminants on an industrial scale would create an unsafe situation. In our laboratory the experiments with obligately alkaliphilic bacteria producing hydrogen as an end metabolic product were performed at different conditions. The mesophilic, haloalkaliphilic and obligately anaerobic bacterium Spirochaeta americana ASpG1T was studied and various cultivation regimes were compared for the most effective hydrogen production. In a highly mineralized media with pH 9.5-10.0 not many known methanogens are capable of growth, and the probability of developing pathogenic contaminants is theoretically is close to zero (in medicine carbonate- saturated solutions are applied as antiseptics). Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as a safe and economical process for large-scale industrial bio-hydrogen production in the future. Here we present and discuss the experimental data

Statistical Exposé of a Multiple-Compartment Anaerobic Reactor Treating Domestic Wastewater.

PubMed

Pfluger, Andrew R; Hahn, Martha J; Hering, Amanda S; Munakata-Marr, Junko; Figueroa, Linda

2018-06-01

  Mainstream anaerobic treatment of domestic wastewater is a promising energy-generating treatment strategy; however, such reactors operated in colder regions are not well characterized. Performance data from a pilot-scale, multiple-compartment anaerobic reactor taken over 786 days were subjected to comprehensive statistical analyses. Results suggest that chemical oxygen demand (COD) was a poor proxy for organics in anaerobic systems as oxygen demand from dissolved inorganic material, dissolved methane, and colloidal material influence dissolved and particulate COD measurements. Additionally, univariate and functional boxplots were useful in visualizing variability in contaminant concentrations and identifying statistical outliers. Further, significantly different dissolved organic removal and methane production was observed between operational years, suggesting that anaerobic reactor systems may not achieve steady-state performance within one year. Last, modeling multiple-compartment reactor systems will require data collected over at least two years to capture seasonal variations of the major anaerobic microbial functions occurring within each reactor compartment.

Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes

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

García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh

2015-01-15

Highlights: • Fractionation of solid wastes into readily and slowly biodegradable fractions. • Kinetic coefficients estimation from mono-digestion batch assays. • Validation of kinetic coefficients with a co-digestion continuous experiment. • Simulation of batch and continuous experiments with an ADM1-based model. - Abstract: A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowlymore » biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 g VS/L d. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.« less

Monitoring CO2 invasion processes at the pore scale using geological labs on chip.

PubMed

Morais, S; Liu, N; Diouf, A; Bernard, D; Lecoutre, C; Garrabos, Y; Marre, S

2016-09-21

In order to investigate at the pore scale the mechanisms involved during CO2 injection in a water saturated pore network, a series of displacement experiments is reported using high pressure micromodels (geological labs on chip - GLoCs) working under real geological conditions (25 < T (°C) < 75 and 4.5 < p (MPa) < 8). The experiments were focused on the influence of three experimental parameters: (i) the p, T conditions, (ii) the injection flow rates and (iii) the pore network characteristics. By using on-chip optical characterization and imaging approaches, the CO2 saturation curves as a function of either time or the number of pore volume injected were determined. Three main mechanisms were observed during CO2 injection, namely, invasion, percolation and drying, which are discussed in this paper. Interestingly, besides conventional mechanisms, two counterintuitive situations were observed during the invasion and drying processes.

Online oxygen control for sulfide oxidation in anaerobic treatment of high-sulfate wastewater.

PubMed

Khanal, Samir Kumar; Huang, Ju-Chang

2006-04-01

A new technique for sulfide control was investigated in an upflow-anaerobic filter (UAF) treating high-strength, sulfate-rich wastewater. The technique used periodic oxygen injection using oxidation-reduction potential (ORP) as a controlling parameter to regulate oxygen injection. The UAF was operated at a constant influent total-organic carbon of 6740 mg/L but with different influent sulfates of 1000, 3000, and 6000 mg/L. At 1000 and 3000 mg/L influent sulfates, the produced sulfide did not impose any inhibition to methane-producing bacteria (MPB). However, at 6000 mg/L influent sulfate, the produced dissolved sulfide of 804 mg S/L (free sulfide = 280 mg S/L) severely inhibited the methanogenesis, but not the sulfidogenesis. Upon oxygen injection at elevated ORP of -265 mV, sulfides were almost completely eliminated with a concomitant improvement in methane yield by 46%. If oxygenation was excessive because of an oversetting of ORP, the excess oxygen could be used rapidly by facultative heterotrophs, thereby protecting the MPB from oxygen stress. Regarding online sulfide oxidation, it was found that the biogas and injected oxygen needed to pass through an aqueous layer containing trace metals, which were found to have a significant catalytic effect on abiotic sulfide oxidation.

Berkeley Lab Training

Science.gov Websites

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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...

Anaerobic digestion of glycerol derived from biodiesel manufacturing.

PubMed

Siles López, José Angel; Martín Santos, María de Los Angeles; Chica Pérez, Arturo Francisco; Martín Martín, Antonio

2009-12-01

The anaerobic digestion of glycerol derived from biodiesel manufacturing, in which COD was found to be 1010 g/kg, was studied in batch laboratory-scale reactors at mesophilic temperature using granular and non-granular sludge. Due to the high KOH concentration of this by-product, H(3)PO(4) was added to recover this alkaline catalyst as agricultural fertilizer (potassium phosphates). Although it would not be economically viable, a volume of glycerol was distilled and utilised as reference substrate. The anaerobic revalorisation of glycerol using granular sludge achieved a biodegradability of around 100%, while the methane yield coefficient was 0.306 m(3) CH(4)/kg acidified glycerol. Anaerobic digestion could be a good option for revalorising this available, impure and low priced by-product derived from the surplus of biodiesel companies. The organic loading rate studied was 0.21-0.38 g COD/g VSS d, although an inhibition phenomenon was observed at the highest load.

Microbial community structures in an integrated two-phase anaerobic bioreactor fed by fruit vegetable wastes and wheat straw.

PubMed

Wang, Chong; Zuo, Jiane; Chen, Xiaojie; Xing, Wei; Xing, Linan; Li, Peng; Lu, Xiangyang; Li, Chao

2014-12-01

The microbial community structures in an integrated two-phase anaerobic reactor (ITPAR) were investigated by 16S rDNA clone library technology. The 75L reactor was designed with a 25L rotating acidogenic unit at the top and a 50L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales, Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid (VFA) concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient. Copyright © 2014. Published by Elsevier B.V.

The Impact of Temperature on Anaerobic Biological Perchlorate Treatment

EPA Science Inventory

A 20-month pilot-scale study was conducted to examine the impact of temperature on the performance of an anaerobic biological contactor used to treat perchlorate-contaminated water. The contactor was successfully acclimated with indigenous micro-organisms. Influent temperatures...

Anaerobic power and physical function in strength-trained and non-strength-trained older adults.

PubMed

Slade, Jill M; Miszko, Tanya A; Laity, Jennifer H; Agrawal, Subodoh K; Cress, M Elaine

2002-03-01

Challenging daily tasks, such as transferring heavy items or rising from the floor, may be dependent on the ability to generate short bursts of energy anaerobically. The purposes of this study were to determine if strength-trained (ST) older adults have higher anaerobic power output compared with non-strength-trained (NST) older adults and to determine the relationship between anaerobic power and performance-based physical function. Thirty-five men and women (age 71.5 +/- 6.4 years, mean +/- SD; NST: n = 18, ST: n = 17) were grouped by training status. Outcome variables included relative anaerobic power (Wingate test), physical function measured with the Continuous Scale Physical Functional Performance Test (CS-PFP, scaled 0 to 100), and anthropometric lean thigh volume (LTV). Analysis of covariance (with age and sex as covariates) was used to determine group differences in the dependent variables listed above. Pearson's r was used to determine the relationship between anaerobic power, CS-PFP total score (TOT), and CS-PFP lower body strength domain score (LBS). The ST group had significantly higher mean anaerobic power (NST 58.9 +/- 16 W/l, ST 96.3 +/- 23 W/l), CS-PFP total (NST 61.2 +/- 13, ST 73.7 +/- 8), and LBS (NST 54.1 +/- 17, ST 70.9 +/- 8) compared with the NST group (p <.05). However, LTV was similar for both groups (NST 3.323 +/- 0.75; ST 3.179 +/- 0.79), which suggests that the ST group had higher muscle quality compared with the NST group. Anaerobic power was significantly related to TOT (r =.611, p =.001) and LBS (r =.650, p =.001). High levels of physical function in ST older adults may in part be explained by higher levels of anaerobic power associated with strength training.

Anaerobic rumen SBR for degradation of cellulosic material.

PubMed

Barnes, S P; Keller, J

2004-01-01

Hydrolysis of organic particulates under anaerobic conditions is generally regarded as the rate limiting step in solid digestion processes. Rumen-based ecosystems appear to achieve very high hydrolysis rates for cellulosic organic material. This study aimed at the development and demonstration of an anaerobic sequencing batch reactor (SBR) process operating with a rumen-based microbial inoculum. Fibrous alpha cellulose was used as sole carbon substrate and the use of an SBR operating cycle allowed the utilisation of a high liquid flow rate (hydraulic retention time of 0.67 d) while maintaining a much longer solids retention time of 7 d. Complete mass balances for carbon and nitrogen, as well as COD balancing allowed the full characterisation of the process stoichiometry and kinetics. Elemental analysis of the biomass revealed a composition of C5H4.8O2.4N0.7, which is quite different from other generic biomass compositions used in the literature. The anaerobic rumen SBR was compared with another rumen-based reactor system in the literature which used a continuous filtration process for solid/liquid separation. This comparison showed that the volatile fatty acid production rate from cellulose in the anaerobic SBR was comparable with the performance achieved in the continuous system, although loading, substrate type and media composition were quite different between these two studies. Further evaluation of the anaerobic rumen SBR is required to determine its practical application for other substrates and to demonstrate the scale-up potential of this concept.

Palm oil mill effluent treatment using a two-stage microbial fuel cells system integrated with immobilized biological aerated filters.

PubMed

Cheng, Jia; Zhu, Xiuping; Ni, Jinren; Borthwick, Alistair

2010-04-01

An integrated system of two-stage microbial fuel cells (MFCs) and immobilized biological aerated filters (I-BAFs) was used to treat palm oil mill effluent (POME) at laboratory scale. By replacing the conventional two-stage up-flow anaerobic sludge blanket (UASB) with a newly proposed upflow membrane-less microbial fuel cell (UML-MFC) in the integrated system, significant improvements on NH(3)-N removal were observed and direct electricity generation implemented in both MFC1 and MFC2. Moreover, the coupled iron-carbon micro-electrolysis in the cathode of MFC2 further enhanced treatment efficiency of organic compounds. The I-BAFs played a major role in further removal of NH(3)-N and COD. For influent COD and NH(3)-N of 10,000 and 125 mg/L, respectively, the final effluents COD and NH(3)-N were below 350 and 8 mg/L, with removal rates higher than 96.5% and 93.6%. The GC-MS analysis indicated that most of the contaminants were satisfactorily biodegraded by the integrated system. Copyright 2009 Elsevier Ltd. All rights reserved.

Effect of thermal hydrolysis pre-treatment on anaerobic digestion of municipal biowaste: a pilot scale study in China.

PubMed

Zhou, Yingjun; Takaoka, Masaki; Wang, Wei; Liu, Xiao; Oshita, Kazuyuki

2013-07-01

Co-digestion of wasted sewage sludge, restaurant kitchen waste, and fruit-vegetable waste was carried out in a pilot plant with thermal hydrolysis pre-treatment. Steam was used as heat source for thermal hydrolysis. It was found 38.3% of volatile suspended solids were dissolved after thermal hydrolysis, with digestibility increased by 115%. These results were more significant than those from lab studies using electricity as heat source due to more uniform heating. Anaerobic digesters were then operated under organic loading rates of about 1.5 and 3 kg VS/(m³ d). Little difference was found for digesters with and without thermal pre-treatment in biogas production and volatile solids removal. However, when looking into the digestion process, it was found digestion rate was almost doubled after thermal hydrolysis. Digester was also more stable with thermal hydrolysis pre-treatment. Less volatile fatty acids (VFAs) were accumulated and the VFAs/alkalinity ratio was also lower. Batch experiments showed the lag phase can be eliminated by thermal pre-treatment, implying the advantage could be more significant under a shorter hydraulic retention time. Moreover, it was estimated energy cost for thermal hydrolysis can be partly balanced by decreasing viscosity and improving dewaterability of the digestate. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

POLISHING EFFLUENT FROM A PERCHLORATE-REDUCING ANAEROBIC BIOLOGICAL CONTACTOR

EPA Science Inventory

The U.S. Environmental Protection Agency undertook at 3 ½ year pilot-scale biological perchlorate treatment study that included two long (311 and 340 days) examinations of anaerobic effluent polishing. The polishing system consisted of hydrogen peroxide addition and aeration, fo...

Treatment of seafood processing wastewater using upflow microbial fuel cell for power generation and identification of bacterial community in anodic biofilm.

PubMed

Jayashree, C; Tamilarasan, K; Rajkumar, M; Arulazhagan, P; Yogalakshmi, K N; Srikanth, M; Banu, J Rajesh

2016-09-15

Tubular upflow microbial fuel cell (MFC) utilizing sea food processing wastewater was evaluated for wastewater treatment efficiency and power generation. At an organic loading rate (OLR) of 0.6 g d(-1), the MFC accomplished total and soluble chemical oxygen demand (COD) removal of 83 and 95%, respectively. A maximum power density of 105 mW m(-2) (2.21 W m(-3)) was achieved at an OLR of 2.57 g d(-1). The predominant bacterial communities of anode biofilm were identified as RB1A (LC035455), RB1B (LC035456), RB1C (LC035457) and RB1E (LC035458). All the four strains belonged to genera Stenotrophomonas. The results of the study reaffirms that the seafood processing wastewater can be treated in an upflow MFC for simultaneous power generation and wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gas-solid fluidized bed reactors: Scale-up, flow regimes identification and hydrodynamics

NASA Astrophysics Data System (ADS)

Zaid, Faraj Muftah

This research studied the scale-up, flow regimes identification and hydrodynamics of fluidized beds using 6-inch and 18- inch diameter columns and different particles. One of the objectives was to advance the scale-up of gas-solid fluidized bed reactors by developing a new mechanistic methodology for hydrodynamic similarity based on matching the radial or diameter profile of gas phase holdup, since gas dynamics dictate the hydrodynamics of these reactors. This has been successfully achieved. However, the literature reported scale-up methodology based on matching selected dimensionless groups was examined and it was found that it was not easy to match the dimensionless groups and hence, there was some deviation in the hydrodynamics of the studied two different fluidized beds. A new technique based on gamma ray densitometry (GRD) was successfully developed and utilized to on-line monitor the implementation of scale-up, to identify the flow regime, and to measure the radial or diameter profiles of gas and solids holdups. CFD has been demonstrated as a valuable tool to enable the implementation of the newly developed scale-up methodology based on finding the conditions that provide similar or closer radial profile or cross sectional distribution of the gas holdup. As gas velocity increases, solids holdup in the center region of the column decreases in the fully developed region of both 6 inch and 18 inch diameter columns. Solids holdup increased with the increase in the particles size and density. Upflowing particles velocity increased with the gas velocity and became steeper at high superficial gas velocity at all axial heights where the center line velocity became higher than that in the wall region. Smaller particles size and lower density gave larger upflowing particles velocity. Minimum fluidization velocity and transition velocity from bubbly to churn turbulent flow regimes were found to be lower in 18 inch diameter column compared to those obtained in 6 inch

Leaching behaviour of different scrap materials at recovery and recycling companies: full-, pilot- and lab-scale investigation.

PubMed

Blondeel, E; Chys, M; Depuydt, V; Folens, K; Du Laing, G; Verliefde, A; Van Hulle, S W H

2014-12-01

Scrap material recovery and recycling companies are confronted with waste water that has a highly fluctuating flow rate and composition. Common pollutants, such as COD, nutrients and suspended solids, potentially toxic metals, polyaromatic hydrocarbons and poly chlorinated biphenyls can exceed the discharge limits. An analysis of the leaching behaviour of different scrap materials and scrap yard sweepings was performed at full-scale, pilot-scale and lab-scale in order to find possible preventive solutions for this waste water problem. The results of these leaching tests (with concentrations that frequently exceeded the Flemish discharge limits) showed the importance of regular sweeping campaigns at the company, leak proof or covered storage of specific scrap materials and oil/water separation on particular leachates. The particulate versus dissolved fraction was also studied for the pollutants. For example, up to 98% of the polyaromatic hydrocarbons, poly chlorinated biphenyls and some metals were in the particulate form. This confirms the (potential) applicability of sedimentation and filtration techniques for the treatment of the majority of the leachates, and as such the rainwater run-off as a whole. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anaerobic Digestion and its Applications

EPA Science Inventory

Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

Anaerobic Biodegradation of Detergent Surfactants

PubMed Central

Merrettig-Bruns, Ute; Jelen, Erich

2009-01-01

Detergent surfactants can be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants).

Anaerobic Digestion of Laminaria japonica Waste from Industrial Production Residues in Laboratory- and Pilot-Scale

PubMed Central

Barbot, Yann Nicolas; Thomsen, Claudia; Thomsen, Laurenz; Benz, Roland

2015-01-01

The cultivation of macroalgae to supply the biofuel, pharmaceutical or food industries generates a considerable amount of organic residue, which represents a potential substrate for biomethanation. Its use optimizes the total resource exploitation by the simultaneous disposal of waste biomaterials. In this study, we explored the biochemical methane potential (BMP) and biomethane recovery of industrial Laminaria japonica waste (LJW) in batch, continuous laboratory and pilot-scale trials. Thermo-acidic pretreatment with industry-grade HCl or industrial flue gas condensate (FGC), as well as a co-digestion approach with maize silage (MS) did not improve the biomethane recovery. BMPs between 172 mL and 214 mL g−1 volatile solids (VS) were recorded. We proved the feasibility of long-term continuous anaerobic digestion with LJW as sole feedstock showing a steady biomethane production rate of 173 mL g−1 VS. The quality of fermentation residue was sufficient to serve as biofertilizer, with enriched amounts of potassium, sulfur and iron. We further demonstrated the upscaling feasibility of the process in a pilot-scale system where a CH4 recovery of 189 L kg−1 VS was achieved and a biogas composition of 55% CH4 and 38% CO2 was recorded. PMID:26393620

Biomass growth restriction in a packed bed reactor

DOEpatents

Griffith, William L.; Compere, Alicia L.

1978-01-01

When carrying out continuous biologically catalyzed reactions with anaerobic microorganisms attached to a support in an upflow packed bed column, growth of the microorganisms is restricted to prevent the microorganisms from plugging the column by limiting the availability of an essential nutrient and/or by the presence of predatory protozoa which consume the anaerobic microorganisms. A membrane disruptive detergent may be provided in the column to lyse dead microorganisms to make them available as nutrients for live microorganisms.

Biogas and biohydrogen production potential of high strength automobile industry wastewater during anaerobic degradation.

PubMed

Bajaj, Mini; Winter, Josef

2013-10-15

High strength automobile industry wastewater, collected from decanters (DECA) of the pre-treatment plant after oil, grease and sludge separation, was investigated for production of methane in the absence and presence of glucose or excess aerobic sludge (AS) from a lab scale suspension reactor as co-substrates. The highest methane production from DECA wastewater was 335.4 L CH4/kg CODsoluble removal which decreased in the presence of the co-substrates to 232.5 (with 2 g/L glucose) and to 179 (with 40% AS) L CH4/kg CODsoluble removal, respectively. Around 95% of total methane was produced within 5 days of incubation of DECA at 37 °C when no co-substrate was added. Addition of co-substrates did not improve biodegradation of DECA but overall methane production from DECA + co-substrates was increased due to co-substrate biodegradation. The anaerobic inoculum, capable of producing 2.4 mol of hydrogen/mol of glucose under zinc induced inhibitory conditions, was unable to produce hydrogen from DECA as substrate under the same conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Numerical prediction of wall temperatures for near-critical para-hydrogen in turbulent upflow inside vertical tubes

NASA Technical Reports Server (NTRS)

Bellmore, C. P.; Reid, R. L.

1980-01-01

Presented herein is a method of including density fluctuations in the equations of turbulent transport. Results of a numerical analysis indicate that the method may be used to predict heat transfer for the case of near-critical para-hydrogen in turbulent upflow inside vertical tubes. Wall temperatures, heat transfer coefficients, and velocities obtained by coupling the equations of turbulent momentum and heat transfer with a perturbed equation of state show good agreement with experiment for inlet reduced pressures of 1.28-5.83.

In-situ biogas upgrading during anaerobic digestion of food waste amended with walnut shell biochar at bench scale.

PubMed

Linville, Jessica L; Shen, Yanwen; Ignacio-de Leon, Patricia A; Schoene, Robin P; Urgun-Demirtas, Meltem

2017-06-01

A modified version of an in-situ CO 2 removal process was applied during anaerobic digestion of food waste with two types of walnut shell biochar at bench scale under batch operating mode. Compared with the coarse walnut shell biochar, the fine walnut shell biochar has a higher ash content (43 vs. 36 wt%) and higher concentrations of calcium (31 vs. 19 wt% of ash), magnesium (8.4 vs. 5.6 wt% of ash) and sodium (23.4 vs. 0.3 wt% of ash), but a lower potassium concentration (0.2 vs. 40% wt% of ash). The 0.96-3.83 g biochar (g VS added ) -1 fine walnut shell biochar amended digesters produced biogas with 77.5%-98.1% CH 4 content by removing 40%-96% of the CO 2 compared with the control digesters at mesophilic and thermophilic temperature conditions. In a direct comparison at 1.83 g biochar (g VS added ) -1 , the fine walnut shell biochar amended digesters (85.7% CH 4 content and 61% CO 2 removal) outperformed the coarse walnut shell biochar amended digesters (78.9% CH 4 content and 51% CO 2 removal). Biochar addition also increased alkalinity as CaCO 3 from 2800 mg L -1 in the control digesters to 4800-6800 mg L -1 , providing process stability for food waste anaerobic digestion.

Microbial community dynamics and biogas production from manure fractions in sludge bed anaerobic digestion.

PubMed

Nordgård, A S R; Bergland, W H; Bakke, R; Vadstein, O; Østgaard, K; Bakke, I

2015-12-01

To elucidate how granular sludge inoculum and particle-rich organic loading affect the structure of the microbial communities and process performance in upflow anaerobic sludge bed (UASB) reactors. We investigated four reactors run on dairy manure filtrate and four on pig manure supernatant for three months achieving similar methane yields. The reactors fed with less particle rich pig manure stabilized faster and had highest capacity. Microbial community dynamics analysed by a PCR/denaturing gradient gel electrophoresis approach showed that influent was a major determinant for the composition of the reactor communities. Comparisons of pre- and non-adapted inoculum in the reactors run on pig manure supernatant showed that the community structure of the nonadapted inoculum adapted in approximately two months. Microbiota variance partitioning analysis revealed that running time, organic loading rate and inoculum together explained 26 and 31% of the variance in bacterial and archaeal communities respectively. The microbial communities of UASBs adapted to the reactor conditions in treatment of particle rich manure fractions, obtaining high capacity, especially on pig manure supernatant. These findings provide relevant insight into the microbial community dynamics in startup and operation of sludge bed reactors for methane production from slurry fractions, a major potential source of biogas. © 2015 The Society for Applied Microbiology.

Visualization of High Latitude Ion Upflow in Support of the Image Mission

NASA Technical Reports Server (NTRS)

Wilson, Gordon R.

1996-01-01

The study of the magnetosphere is a 400 year old science that began with the publication by Gilbert, in 1600, of his hypotheses that the Earth was a giant magnet. Since then we have learned many things about the magnetosphere, particularly in the last 40 years of the space age, but we still have many unanswered questions. In spite of the many thousands of observations of this system we still lack a global understanding of how it works. This is due to its large size and tenuous nature that mean that any measurement made of the fields or particles involved only give one a knowledge of the local conditions at a given time. To gain a global perspective through such observations would require the simultaneous operation of thousands of satellites spread throughout the magnetospheric system in addition to observations made on the ground. Such a program would be impractical at least from financial considerations. What is needed for the advancement of magnetospheric physics is to develop the same capabilities that astrophysicists, solar physicists and meteorologists have been using for years --- the ability to stand back from the object under study and see it in its entirety. The challenge for doing this for the magnetosphere is that the particle densities are very low and the material is, for the most part, not luminous. In the last 25 years several ideas have been proposed that would allow at least the imaging of certain portions of the magnetosphere. These include imaging of the plasmasphere through the resonant scattering of solar 304 A from He+ ions, imaging of various hot plasma populations (i.e. the ring current, plasmasheet, upflowing ionospheric ions, etc.) from the neutral atoms that result when ions of these populations charge exchange with the hydrogen geocorona, and imaging the aurora at various wavelengths in the far ultraviolet. In addition, a novel technique for probing various boundaries in the magnetosphere by bouncing low frequency radio waves off of them

Anaerobic digestion of macroalgae: methane potentials, pre-treatment, inhibition and co-digestion.

PubMed

Nielsen, H B; Heiske, S

2011-01-01

In the present study we tested four macroalgae species--harvested in Denmark--for their suitability of bioconversion to methane. In batch experiments (53 degrees C) methane yields varied from 132 ml g volatile solids(-1) (VS) for Gracillaria vermiculophylla, 152 mi gVS(-1) for Ulva lactuca, 166 ml g VS(-1) for Chaetomorpha linum and 340 ml g VS(-1) for Saccharina latissima following 34 days of incubation. With an organic content of 21.1% (1.5-2.8 times higher than the other algae) S. latissima seems very suitable for anaerobic digestion. However, the methane yields of U. lactuca, G. vermiculophylla and C. linum could be increased with 68%, 11% and 17%, respectively, by pretreatment with maceration. U. lactuca is often observed during 'green tides' in Europe and has a high cultivation potential at Nordic conditions. Therefore, U. lactuca was selected for further investigation and co-digested with cattle manure in a lab-scale continuously stirred tank reactor. A 48% increase in methane production rate of the reactor was observed when the concentration of U. lactuca in the feedstock was 40% (VS basis). Increasing the concentration to 50% had no further effect on the methane production, which limits the application of this algae at Danish centralized biogas plant.

Genome-centric resolution of microbial diversity, metabolism and interactions in anaerobic digestion.

PubMed

Vanwonterghem, Inka; Jensen, Paul D; Rabaey, Korneel; Tyson, Gene W

2016-09-01

Our understanding of the complex interconnected processes performed by microbial communities is hindered by our inability to culture the vast majority of microorganisms. Metagenomics provides a way to bypass this cultivation bottleneck and recent advances in this field now allow us to recover a growing number of genomes representing previously uncultured populations from increasingly complex environments. In this study, a temporal genome-centric metagenomic analysis was performed of lab-scale anaerobic digesters that host complex microbial communities fulfilling a series of interlinked metabolic processes to enable the conversion of cellulose to methane. In total, 101 population genomes that were moderate to near-complete were recovered based primarily on differential coverage binning. These populations span 19 phyla, represent mostly novel species and expand the genomic coverage of several rare phyla. Classification into functional guilds based on their metabolic potential revealed metabolic networks with a high level of functional redundancy as well as niche specialization, and allowed us to identify potential roles such as hydrolytic specialists for several rare, uncultured populations. Genome-centric analyses of complex microbial communities across diverse environments provide the key to understanding the phylogenetic and metabolic diversity of these interactive communities. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Microbial community changes with decaying chloramine residuals in a lab-scale system.

PubMed

Bal Krishna, K C; Sathasivan, Arumugam; Ginige, Maneesha P

2013-09-01

When chloramine is used as a disinfectant, managing an acceptable "residual" throughout the water distribution systems particularly once nitrification has set in is challenging. Managing chloramine decay prior to the onset of nitrification through effective control strategies is important and to-date the strategies developed around nitrification has been ineffective. This study aimed at developing a more holistic knowledge on how decaying chloramine and nitrification metabolites impact microbial communities in chloraminated systems. Five lab-scale reactors (connected in series) were operated to simulate a full-scale chloraminated distribution system. Culture independent techniques (cloning and qPCR) were used to characterise and quantify the mixed microbial communities in reactors maintaining a residual of high to low (2.18-0.03 mg/L). The study for the first time associates chloramine residuals and nitrification metabolites to different microbial communities. Bacterial classes Solibacteres, Nitrospira, Sphingobacteria and Betaproteobacteria dominated at low chloramine residuals whereas Actinobacteria and Gammaproteobacteria dominated at higher chloramine residuals. Prior to the onset of nitrification bacterial genera Pseudomonas, Methylobacterium and Sphingomonas were found to be dominant and Sphingomonas in particular increased with the onset of nitrification. Nitrosomonas urea, oligotropha, and two other novel ammonia-oxidizing bacteria were detected once the chloramine residuals had dropped below 0.65 mg/L. Additionally nitrification alone failed to explain chloramine decay rates observed in these reactors. The finding of this study is expected to re-direct the focus from nitrifiers to heterotrophic bacteria, which the authors believe could hold the key towards developing a control strategy that would enable better management of chloramine residuals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Association Between Anaerobic Metabolic Demands During Simulated Brazilian Jiu-Jitsu Combat and Specific Jiu-Jitsu Anaerobic Performance Test.

PubMed

Villar, Rodrigo; Gillis, Jason; Santana, Givanildo; Pinheiro, Daniel S; Almeida, André L R A

2018-02-01

Villar, R, Gillis, J, Santana, G, Pinheiro, DS, and Almeida, ALRA. Association between anaerobic metabolic demands during simulated Brazilian jiu-jitsu combat and specific jiu-jitsu anaerobic performance test. J Strength Cond Res 32(2): 432-440, 2018-The aims of this study were to design a specific Jiu-Jitsu anaerobic performance test (JJAPT) and investigate the relationship between blood lactate ([La]), heart rate (HR), and rating of perceived exertion (RPE) during simulated Brazilian Jiu-Jitsu combat (SBJJC) and JJAPT. Nine male elite Brazilian medium heavy weight athletes performed a 10-minute SBJJC and JJAPT that required performance of a common BJJ technique for 5 consecutive bouts of 1-minute with 45-second rest between bouts. [La] was measured by a lactate analyzer, HR by an HR monitor, and RPE using Borg's scale, and the number of repetitions of butterfly lifts (NBL) was recorded. During JJAPT, NBL decreased in the fourth and fifth bouts (p ≤ 0.05) with increases in [La], HR, and RPE (p ≤ 0.05), indicating that the JJAPT measured anaerobic performance. [La] during SBJJC was not different than [La] at the third and fourth bouts, but was significantly different than the fifth bout (p ≤ 0.05). [La] showed strong correlation between SBJJC and JJAPT for the third (r = 0.80, p ≤ 0.05), fourth (r = 0.83, p ≤ 0.05), and fifth (r = 0.82, p ≤ 0.05) bouts, but not between the HR and RPE. The JJAPT with 4 bouts presented the best combination of stimulus and highest correlation with SBJJC, supporting its use to assess anaerobic performance of BJJ athletes. These data will aid coaches and athletes to better understand the demands of their sport and may help to monitor adaptation in sport-specific performance across periodized training plans.

[Current clinical significance of anaerobic bacteremia].

PubMed

Jirsa, Roman; Marešová, Veronika; Brož, Zdeněk

2010-10-01

to estimate tje current clinical significance of anaerobic bacteremia in a group of Czech hospitals. this retrospective analysis comprised 8 444 anaerobic blood cultures in patients admitted to four Czech hospitals between 2004 and 2007. in 16 patients, blood cultures yielded significant anaerobic bacteria. Thus, anaerobic bacteremia accounted for less than 2 % of clinically significant bacteremia. Four patients (18 %) died but none of the deaths could be clearly attributable to anaerobic bacteria in the bloodstream. The most common comorbidities predisposing to anaerobic bacteremia and the most frequent sources of infection were similar to those reported by other authors. The majority of anaerobic bacteremia cases were due to gram-negative bacteria, followed by Clostridium perfringens and, surprisingly, Eubacterium spp. (particularly Eubacterium lentum). anaerobic bacteremia remains rare. The comparison of our data with those by other authors suggests that (despite the reported high mortality) the actual clinical significance of anaerobic bacteremia is rather controversial and that the anaerobic bacteremia might not correspond to more serious pathogenic role of the anaerobic bacteria as the source of infection.

Optimization of micro-aeration intensity in acidogenic reactor of a two-phase anaerobic digester treating food waste.

PubMed

Xu, Suyun; Selvam, Ammaiyappan; Wong, Jonathan W C

2014-02-01

Micro-aeration is known to promote the activities of hydrolytic exo-enzymes and used as a strategy to improve the hydrolysis of particulate substrate. The effect of different micro-aeration rates, 0, 129, 258, and 387 L-air/kg TS/d (denoted as LBR-AN, LBR-6h, LBR-3h and LBR-2h, respectively) on the solubilization of food waste was evaluated at 35°C in four leach bed reactors (LBR) coupled with methanogenic upflow anaerobic sludge blanket (UASB) reactor. Results indicate that the intensity of micro-aeration influenced the hydrolysis and methane yield. Adequate micro-aeration intensity in LBR-3h and LBR-2h significantly enhanced the carbohydrate and protein hydrolysis by 21-27% and 38-64% respectively. Due to the accelerated acidogenesis, more than 3-fold of acetic acid and butyric acid were produced in LBR-3h as compared to the anaerobic treatment LBR-AN resulting in the maximum methane yield of 0.27 L CH4/g VS(added) in the UASB. The performance of LBR-6h with inadequate aeration was similar to that of LBR-AN with a comparable hydrolysis degree. Nevertheless, higher aeration intensity in LBR-2h was also unfavorable for methane yield due to significant biomass generation and CO2 respiration of up to 18.5% and 32.8% of the total soluble hydrolysate, respectively. To conclude, appropriate micro-aeration rate can promote the hydrolysis of solid organic waste and methane yield without undesirable carbon loss and an aeration intensity of 258 L-air/kg TS/d is recommended for acidogenic LBR treating food waste. Copyright © 2013 Elsevier Ltd. All rights reserved.

Predominant Lactobacillus species types of vaginal microbiota in pregnant Korean women: quantification of the five Lactobacillus species and two anaerobes.

PubMed

Kim, Jeong Hyun; Yoo, Seung Min; Sohn, Yong Hak; Jin, Chan Hee; Yang, Yun Suk; Hwang, In Taek; Oh, Kwan Young

2017-10-01

To investigate the predominant Lactobacillus species types (LSTs) of vaginal microbiota in pregnant Korean women by quantifying five Lactobacillus species and two anaerobes. In all, 168 pregnant Korean women under antenatal care at Eulji University Hospital and local clinics were enrolled in the prospective cohort study during pregnancy (10-14 weeks). Vaginal samples were collected with Eswab for Quantitative polymerase chain reaction (qPCR) and stored in a -80 °C freezer. qPCR was performed for five Lactobacillus species and two anaerobes. To identify the predominant LSTs, quantifications were analyzed by the Cluster and Tree View programs of Eisen Lab. Also the quantifications were compared among classified groups. L. crispatus and L. iners were most commonly found in pregnant Korean women, followed by L. gasseri and L. jensenii; L. vaginalis was nearly absent. Five types (four predominant LSTs and one predominant anaerobe type without predominant Lactobacillus species) were classified. Five predominant LSTs were identified in vaginal microbiota of pregnant Korean women. L. crispatus and L. iners predominant types comprised a large proportion.

e-Learning - Physics Labs

NASA Astrophysics Data System (ADS)

Mohottala, Hashini

2014-03-01

The general student population enrolled in any college level class is highly diverse. An increasing number of ``nontraditional'' students return to college and most of these students follow distance learning degree programs while engaging in their other commitments, work and family. However, those students tend to avoid taking science courses with labs, mostly because of the incapability of remotely completing the lab components in such courses. In order to address this issue, we have come across a method where introductory level physics labs can be taught remotely. In this process a lab kit with the critical lab components that can be easily accessible are conveniently packed into a box and distributed among students at the beginning of the semester. Once the students are given the apparatus they perform the experiments at home and gather data All communications with reference to the lab was done through an interactive user-friendly webpage - Wikispaces (WikiS). Students who create pages on WikiS can submit their lab write-ups, embed videos of the experiments they perform, post pictures and direct questions to the lab instructor. The students who are enrolled in the same lab can interact with each other through WikiS to discuss labs and even get assistance.

INCREASE OF INDICATOR ORGANISMS FOLLOWING ANAEROBIC DIGESTION AND CENTRIFUGE DEWATERING.

EPA Science Inventory

The Water Environment Research Foundation (WERF) recently published a report titled “Examination of Reactivation and Regrowth of Fecal Coliforms in Anaerobically Digested Sludges”. Seven full-scale publicly owned treatment facilities were sampled several times to determine if bac...

Yolo County's Accelerated Anaerobic and Aerobic Composting (Full-Scale Controlled Landfill Bioreactor) Project

NASA Astrophysics Data System (ADS)

Yazdani, R.; Kieffer, J.; Akau, H.; Augenstein, D.

2002-12-01

Sanitary landfilling is the dominant method of solid waste disposal in the United States, accounting for about 217 million tons of waste annually (U.S. EPA, 1997) and has more than doubled since 1960. In spite of increasing rates of reuse and recycling, population and economic growth will continue to render landfilling as an important and necessary component of solid waste management. Yolo County Department of Planning and Public Works, Division of Integrated Waste Management is demonstrating a new landfill technology called Bioreactor Landfill to better manage solid waste. In a Bioreactor Landfill, controlled quantities of liquid (leachate, groundwater, gray-water, etc.) are added and recirculated to increase the moisture content of the waste and improve waste decomposition. As demonstrated in a small-scale demonstration project at the Yolo County Central Landfill in 1995, this process significantly increases the biodegradation rate of waste and thus decreases the waste stabilization and composting time (5 to 10 years) relative to what would occur within a conventional landfill (30 to 50 years or more). When waste decomposes anaerobically (in absence of oxygen), it produces landfill gas (biogas). Biogas is primarily a mixture of methane, a potent greenhouse gas, carbon dioxide, and small amounts of Volatile Organic Compounds (VOC's) which can be recovered for electricity or other uses. Other benefits of a bioreactor landfill composting operation include increased landfill waste settlement which increases in landfill capacity and life, improved leachate chemistry, possible reduction of landfill post-closure management time, opportunity to explore decomposed waste for landfill mining, and abatement of greenhouse gases through highly efficient methane capture over a much shorter period of time than is typical of waste management through conventional landfilling. This project also investigates the aerobic decomposition of waste of 13,000 tons of waste (2.5 acre) for

A STUDY OF LAND APPLICATION OF ANAEROBICALLY DIGESTED BIOSOLIDS

EPA Science Inventory

A field-scale research project was conducted in 2004-2005 to evaluate land application of anaerobically digested biosolids at agronomic levels. Biosolids had not been applied to this land previously. For this study, biosolids wee applied in a 100-m diameter circle by a side dis...

Investigations into Improving Dewaterability at a Bio-P/Anaerobic Digestion Plant.

PubMed

Alm, Rebecca; Sealock, Adam W; Nollet, Yabing; Sprouse, George

2016-11-01

  Metropolitan Council Environmental Services has observed poorer than expected dewatering performance at its Empire Plant. This plant has both anaerobic digestion and enhanced biological phosphorus removal in its treatment train. A research program using pilot-scale anaerobic digesters investigated potential solutions to the plant's poor dewaterability. The dewaterability goal was to increase the cake solids from 12% total solids (TS) to 16% TS or higher. This research investigated 20 different reactor conditions including chemical, feed sludge, and digested sludge treatments. At the pilot scale, unaerated storage of waste activated sludge prior to thickening and addition of ferric chloride to digestion was found to achieve dewatered cake solids of nearly 17% TS with the added benefit of reducing polymer demand. Issues including the amount of chemical required and the resulting volatile solids destruction influence the viability of the process change, so a full-scale pilot and financial analysis is recommended before making permanent process changes.

Genome-scale analysis of anaerobic benzoate and phenol metabolism in the hyperthermophilic archaeon Ferroglobus placidus

PubMed Central

Holmes, Dawn E; Risso, Carla; Smith, Jessica A; Lovley, Derek R

2012-01-01

Insight into the mechanisms for the anaerobic metabolism of aromatic compounds by the hyperthermophilic archaeon Ferroglobus placidus is expected to improve understanding of the degradation of aromatics in hot (>80° C) environments and to identify enzymes that might have biotechnological applications. Analysis of the F. placidus genome revealed genes predicted to encode enzymes homologous to those previously identified as having a role in benzoate and phenol metabolism in mesophilic bacteria. Surprisingly, F. placidus lacks genes for an ATP-independent class II benzoyl-CoA (coenzyme A) reductase (BCR) found in all strictly anaerobic bacteria, but has instead genes coding for a bzd-type ATP-consuming class I BCR, similar to those found in facultative bacteria. The lower portion of the benzoate degradation pathway appears to be more similar to that found in the phototroph Rhodopseudomonas palustris, than the pathway reported for all heterotrophic anaerobic benzoate degraders. Many of the genes predicted to be involved in benzoate metabolism were found in one of two gene clusters. Genes for phenol carboxylation proceeding through a phenylphosphate intermediate were identified in a single gene cluster. Analysis of transcript abundance with a whole-genome microarray and quantitative reverse transcriptase polymerase chain reaction demonstrated that most of the genes predicted to be involved in benzoate or phenol metabolism had higher transcript abundance during growth on those substrates vs growth on acetate. These results suggest that the general strategies for benzoate and phenol metabolism are highly conserved between microorganisms living in moderate and hot environments, and that anaerobic metabolism of aromatic compounds might be analyzed in a wide range of environments with similar molecular targets. PMID:21776029

Large-scale laboratory testing of bedload-monitoring technologies: overview of the StreamLab06 Experiments

USGS Publications Warehouse

Marr, Jeffrey D.G.; Gray, John R.; Davis, Broderick E.; Ellis, Chris; Johnson, Sara; Gray, John R.; Laronne, Jonathan B.; Marr, Jeffrey D.G.

2010-01-01

A 3-month-long, large-scale flume experiment involving research and testing of selected conventional and surrogate bedload-monitoring technologies was conducted in the Main Channel at the St. Anthony Falls Laboratory under the auspices of the National Center for Earth-surface Dynamics. These experiments, dubbed StreamLab06, involved 25 researchers and volunteers from academia, government, and the private sector. The research channel was equipped with a sediment-recirculation system and a sediment-flux monitoring system that allowed continuous measurement of sediment flux in the flume and provided a data set by which samplers were evaluated. Selected bedload-measurement technologies were tested under a range of flow and sediment-transport conditions. The experiment was conducted in two phases. The bed material in phase I was well-sorted siliceous sand (0.6-1.8 mm median diameter). A gravel mixture (1-32 mm median diameter) composed the bed material in phase II. Four conventional bedload samplers – a standard Helley-Smith, Elwha, BLH-84, and Toutle River II (TR-2) sampler – were manually deployed as part of both experiment phases. Bedload traps were deployed in study Phase II. Two surrogate bedload samplers – stationarymounted down-looking 600 kHz and 1200 kHz acoustic Doppler current profilers – were deployed in experiment phase II. This paper presents an overview of the experiment including the specific data-collection technologies used and the ambient hydraulic, sediment-transport and environmental conditions measured as part of the experiment. All data collected as part of the StreamLab06 experiments are, or will be available to the research community.

High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation.

PubMed

Ekstrand, Eva-Maria; Karlsson, Marielle; Truong, Xu-Bin; Björn, Annika; Karlsson, Anna; Svensson, Bo H; Ejlertsson, Jörgen

2016-10-01

Kraft fibre sludge from the pulp and paper industry constitutes a new, widely available substrate for the biogas production industry, with high methane potential. In this study, anaerobic digestion of kraft fibre sludge was examined by applying continuously stirred tank reactors (CSTR) with sludge recirculation. Two lab-scale reactors (4L) were run for 800days, one on fibre sludge (R1), and the other on fibre sludge and activated sludge (R2). Additions of Mg, K and S stabilized reactor performance. Furthermore, the Ca:Mg ratio was important, and a stable process was achieved at a ratio below 16:1. Foaming was abated by short but frequent mixing. Co-digestion of fibre sludge and activated sludge resulted in more robust conditions, and high-rate operation at stable conditions was achieved at an organic loading rate of 4g volatile solids (VS)L(-1)day(-1), a hydraulic retention time of 4days and a methane production of 230±10NmL per g VS. Copyright © 2016. Published by Elsevier Ltd.

Assessment of hydrogen metabolism in commercial anaerobic digesters.

PubMed

Kern, Tobias; Theiss, Juliane; Röske, Kerstin; Rother, Michael

2016-05-01

Degradation of biomass in the absence of exogenous electron acceptors via anaerobic digestion involves a syntrophic association of a plethora of anaerobic microorganisms. The commercial application of this process is the large-scale production of biogas from renewable feedstock as an alternative to fossil fuels. After hydrolysis of polymers, monomers are fermented to short-chain fatty acids and alcohols, which are further oxidized to acetate. Carbon dioxide, molecular hydrogen (H2), and acetate generated during the process are converted to methane by methanogenic archaea. Since many of the metabolic pathways as well as the syntrophic interactions and dependencies during anaerobic digestion involve formation, utilization, or transfer of H2, its metabolism and the methanogenic population were assessed in various samples from three commercial biogas plants. Addition of H2 significantly increased the rate of methane formation, which suggested that hydrogenotrophic methanogenesis is not a rate-limiting step during biogas formation. Methanoculleus and Methanosarcina appeared to numerically dominate the archaeal population of the three digesters, but their proportion and the Bacteria-to-Archaea ratio did not correlate with the methane productivity. Instead, hydrogenase activity in cell-free extracts from digester sludge correlated with methane productivity in a positive fashion. Since most microorganisms involved in biogas formation contain this activity, it approximates the overall anaerobic metabolic activity and may, thus, be suitable for monitoring biogas reactor performance.

Microbial Insight into a Pilot-Scale Enhanced Two-Stage High-Solid Anaerobic Digestion System Treating Waste Activated Sludge.

PubMed

Wu, Jing; Cao, Zhiping; Hu, Yuying; Wang, Xiaolu; Wang, Guangqi; Zuo, Jiane; Wang, Kaijun; Qian, Yi

2017-11-30

High solid anaerobic digestion (HSAD) is a rapidly developed anaerobic digestion technique for treating municipal sludge, and has been widely used in Europe and Asia. Recently, the enhanced HSAD process with thermal treatment showed its advantages in both methane production and VS reduction. However, the understanding of the microbial community is still poor. This study investigated microbial communities in a pilot enhanced two-stage HSAD system that degraded waste activated sludge at 9% solid content. The system employed process "thermal pre-treatment (TPT) at 70 °C, thermophilic anaerobic digestion (TAD), and mesophilic anaerobic digestion (MAD)". Hydrogenotrophic methanogens Methanothermobacter spp. dominated the system with relative abundance up to about 100% in both TAD and MAD. Syntrophic acetate oxidation (SAO) bacteria were discovered in TAD, and they converted acetate into H₂ and CO₂ to support hydrogenotrophic methanogenesis. The microbial composition and conversion route of this system are derived from the high solid content and protein content in raw sludge, as well as the operational conditions. This study could facilitate the understanding of the enhanced HSAD process, and is of academic and industrial importance.

Wingate Anaerobic Test peak power and anaerobic capacity classifications for men and women intercollegiate athletes.

PubMed

Zupan, Michael F; Arata, Alan W; Dawson, Letitia H; Wile, Alfred L; Payn, Tamara L; Hannon, Megan E

2009-12-01

The Wingate Anaerobic Test (WAnT) has been established as an effective tool in measuring both muscular power and anaerobic capacity in a 30-second time period; however, there are no published normative tables by which to compare WAnT performance in men and women intercollegiate athletics. The purpose of this study was to develop a classification system for anaerobic peak power and anaerobic capacity for men and women National Collegiate Athletic Association (NCAA) Division I college athletes using the WAnT. A total of 1,585 (1,374 men and 211 women) tests were conducted on athletes ranging from the ages of 18 to 25 years using the WAnT. Absolute and relative peak power and anaerobic capacity data were recorded. One-half standard deviations were used to set up a 7-tier classification system (poor to elite) for these assessments. These classifications can be used by athletes, coaches, and practitioners to evaluate anaerobic peak power and anaerobic capacity in their athletes.

Syntrophic acetate oxidation in two-phase (acid-methane) anaerobic digesters.

PubMed

Shimada, T; Morgenroth, E; Tandukar, M; Pavlostathis, S G; Smith, A; Raskin, L; Kilian, R E

2011-01-01

The microbial processes involved in two-phase anaerobic digestion were investigated by operating a laboratory-scale acid-phase (AP) reactor and analyzing two full-scale, two-phase anaerobic digesters operated under mesophilic (35 °C) conditions. The digesters received a blend of primary sludge and waste activated sludge (WAS). Methane levels of 20% in the laboratory-scale reactor indicated the presence of methanogenic activity in the AP. A phylogenetic analysis of an archaeal 16S rRNA gene clone library of one of the full-scale AP digesters showed that 82% and 5% of the clones were affiliated with the orders Methanobacteriales and Methanosarcinales, respectively. These results indicate that substantial levels of aceticlastic methanogens (order Methanosarcinales) were not maintained at the low solids retention times and acidic conditions (pH 5.2-5.5) of the AP, and that methanogenesis was carried out by hydrogen-utilizing methanogens of the order Methanobacteriales. Approximately 43, 31, and 9% of the archaeal clones from the methanogenic phase (MP) digester were affiliated with the orders Methanosarcinales, Methanomicrobiales, and Methanobacteriales, respectively. A phylogenetic analysis of a bacterial 16S rRNA gene clone library suggested the presence of acetate-oxidizing bacteria (close relatives of Thermacetogenium phaeum, 'Syntrophaceticus schinkii,' and Clostridium ultunense). The high abundance of hydrogen consuming methanogens and the presence of known acetate-oxidizing bacteria suggest that acetate utilization by acetate oxidizing bacteria in syntrophic interaction with hydrogen-utilizing methanogens was an important pathway in the second-stage of the two-phase digestion, which was operated at high ammonium-N concentrations (1.0 and 1.4 g/L). A modified version of the IWA Anaerobic Digestion Model No. 1 (ADM1) with extensions for syntrophic acetate oxidation and weak-acid inhibition adequately described the dynamic profiles of volatile acid production

Single-chamber microbial fuel cells as on-line shock-sensors for volatile fatty acids in anaerobic digesters.

PubMed

Schievano, Andrea; Colombo, Alessandra; Cossettini, Alessandra; Goglio, Andrea; D'Ardes, Vincenzo; Trasatti, Stefano; Cristiani, Pierangela

2018-01-01

In anaerobic digesters (AD), volatile fatty acids (VFAs) concentration is a critical operative parameter, which is usually manually monitored to prevent inhibition of microbial consortia. An on-line VFAs monitoring system as early-warning for increasing concentrations would be of great help for operators. Here, air-cathode membraneless microbial fuel cells (MFCs) were investigated as potential biosensors, whose electrical signal instantaneously moves from its steady value with the accumulation of VFAs in the anodic solution. MFCs were operated equipping four lab-scale ADs with carbon-based electrodes. Reactors were filled with the digestate from a full-scale AD and fed in batch with four kinds of feedstock (cheese whey, kitchen waste, citrus pulp and fishery waste). The MFC signal initially increased in parallel to VFAs production, then tended to a steady value for VFAs concentrations above 1000mg Ac L -1 . Peak concentrations of tVFAs (2500-4500mg Ac L -1 ) and MFCs potentials were negatively correlated (r=0.916, p<0.05), regardless of the type of substrate. Inhibition of the MFC system occurred when VFAs increased fast above 4000mg Ac L -1 . Polarization curves of electrodes stressed that electroactive bacteria on bioanodes were strongly subjected to inhibition. The inhibition of electroactivity on bioanode trended like typical shock-sensors, opening to direct application as early-warning monitoring system in full-scale ADs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advanced anaerobic bioconversion of lignocellulosic waste for bioregenerative life support following thermal water treatment and biodegradation by Fibrobacter succinogenes.

PubMed

Lissens, Geert; Verstraete, Willy; Albrecht, Tobias; Brunner, Gerd; Creuly, Catherine; Seon, Jerome; Dussap, Gilles; Lasseur, Christophe

2004-06-01

The feasibility of nearly-complete conversion of lignocellulosic waste (70% food crops, 20% faecal matter and 10% green algae) into biogas was investigated in the context of a life support project. The treatment comprised a series of processes, i.e., a mesophilic laboratory scale CSTR (continuously stirred tank reactor), an upflow biofilm reactor, a fiber liquefaction reactor employing the rumen bacterium Fibrobacter succinogenes and a hydrothermolysis system in near-critical water. By the one-stage CSTR, a biogas yield of 75% with a specific biogas production of 0.37 l biogas g(-1) VSS (volatile suspended solids) added at a RT (hydraulic retention time) of 20-25 d was obtained. Biogas yields could not be increased considerably at higher RT, indicating the depletion of readily available substrate after 25 d. The solids present in the CSTR-effluent were subsequently treated in two ways. Hydrothermal treatment (T approximately 310-350 degrees C, p approximately 240 bar) resulted in effective carbon liquefaction (50-60% without and 83% with carbon dioxide saturation) and complete sanitation of the residue. Application of the cellulolytic Fibrobacter succinogenes converted remaining cellulose contained in the CSTR-effluent into acetate and propionate mainly. Subsequent anaerobic digestion of the hydrothermolysis and the Fibrobacter hydrolysates allowed conversion of 48-60% and 30%, respectively. Thus, the total process yielded biogas corresponding with conversions up to 90% of the original organic matter. It appears that particularly mesophilic digestion in conjunction with hydrothermolysis at near-critical conditions offers interesting features for (nearly) complete and hygienic carbon and energy recovery from human waste in a bioregenerative life support context.

Effects of mixture ratio on anaerobic co-digestion with fruit and vegetable waste and food waste of China.

PubMed

Lin, Jia; Zuo, Jiane; Gan, Lili; Li, Peng; Liu, Fenglin; Wang, Kaijun; Chen, Lei; Gan, Hainan

2011-01-01

The biochemical methane potentials for typical fruit and vegetable waste (FVW) and food waste (FW) from a northern China city were investigated, which were 0.30, 0.56 m3 CH4/kgVS (volatile solids) with biodegradabilities of 59.3% and 83.6%, respectively. Individual anaerobic digestion testes of FVW and FW we re conducted at the organic loading rate (OLR) of 3 k g VS/(m3.day) using a lab-scale continuous stirred-tank reactor at 350C. FVW could b e digested stably with the biogas production rate of 2.17 m3/(m3 .day)and methane production yield of 0.42 m3 CH4/kg VS. However, anaerobic digestion process for FW was failed due to acids accumulation. The effects of FVW: FW ratio on co-digestion stability and performance were further investigated at the same OLR. At FVW and FW mixing ratios of 2:1 and 1:1, the performance and operation of the digester were maintained stable, with no accumulation of volatile fatty acids (VFA) and ammonia. Changing the feed to a higher FW content in a ratio of FVW to FW 1:2, resulted in an increase inVFAs concentration to 1100-1200 mg/L, and the methanogenesis was slightly inhibited. At the optimum mixture ratio 1:1 for co-digestion of FVW with FW, the methane production yield was 0.49 m3 CH4/kg VS, and the volatile solids and soluble chemical oxygen demand (sCOD) removal efficiencies were 74.9% and 96.1%, respectively.

Assessing the fate of Ascaris suum ova during mesophilic anaerobic digestion.

PubMed

Manser, Nathan D; Wald, Ileana; Ergas, Sarina J; Izurieta, Ricardo; Mihelcic, James R

2015-03-03

There is limited knowledge about the survival of geohelminths, which are soil-transmitted human pathogens, in mesophilic anaerobic digestion processes. This study examined the fate of embryonated and unembryonated Ascaris suum ova in six laboratory-scale mesophilic (35 °C) anaerobic digesters processing swine manure to identify their survival strategies and investigate potential mechanisms to enhance their destruction. There was no significant difference in inactivation of Ascaris suum ova in digesters operated at different solids residence times (SRT) or feeding frequencies. Ova exposed to an anaerobic environment became dormant, or remained unembryonated throughout their residence in the reactors. Approximately 65% of ova were able to retain their viability for up to 16 days, after which the rate of inactivation increased until nearly all ova were nonviable by day 24. In contrast, ova exposed to aerobic conditions did not become dormant and progressed through several developmental stages until day 16, after which nearly all ova were observed to be nonviable. In addition, only 35% of fully developed ova exposed to the anaerobic environment retained their viability by day 16 compared to 65% for dormant ova. Results suggest that some ova are physically destroyed during digestion and ova can be inactivated faster if their development cycle is aerobically triggered before entering the anaerobic digestion process. Results also suggest that transfer of resource recovery technologies such as mesophilic anaerobic digestion to developing world settings must account for local climatic and health conditions so mutually beneficial outcomes can be attained.

Fate of estradiol and testosterone in anaerobic lagoon digestors

USDA-ARS?s Scientific Manuscript database

Laboratory-scale lagoon digestors were constructed, and the fate of 14C-labelled 17ß-estradiol (E2) and testosterone (Test) were monitored for 42 d anaerobically under biological and sterile conditions. Hormone levels decreased in the liquid layer and increased in the sludge with time. At 42 d, 16-2...

Cultivation of Anaerobic and Facultatively Anaerobic Bacteria from Spacecraft-Associated Clean Rooms▿

PubMed Central

Stieglmeier, Michaela; Wirth, Reinhard; Kminek, Gerhard; Moissl-Eichinger, Christine

2009-01-01

In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus. PMID:19363082

Cultivation of anaerobic and facultatively anaerobic bacteria from spacecraft-associated clean rooms.

PubMed

Stieglmeier, Michaela; Wirth, Reinhard; Kminek, Gerhard; Moissl-Eichinger, Christine

2009-06-01

In the course of this biodiversity study, the cultivable microbial community of European spacecraft-associated clean rooms and the Herschel Space Observatory located therein were analyzed during routine assembly operations. Here, we focused on microorganisms capable of growing without oxygen. Anaerobes play a significant role in planetary protection considerations since extraterrestrial environments like Mars probably do not provide enough oxygen for fully aerobic microbial growth. A broad assortment of anaerobic media was used in our cultivation strategies, which focused on microorganisms with special metabolic skills. The majority of the isolated strains grew on anaerobic, complex, nutrient-rich media. Autotrophic microorganisms or microbes capable of fixing nitrogen were also cultivated. A broad range of facultatively anaerobic bacteria was detected during this study and also, for the first time, some strictly anaerobic bacteria (Clostridium and Propionibacterium) were isolated from spacecraft-associated clean rooms. The multiassay cultivation approach was the basis for the detection of several bacteria that had not been cultivated from these special environments before and also led to the discovery of two novel microbial species of Pseudomonas and Paenibacillus.

Microbial community shifts in a farm-scale anaerobic digester treating swine waste: Correlations between bacteria communities associated with hydrogenotrophic methanogens and environmental conditions.

PubMed

Cho, Kyungjin; Shin, Seung Gu; Kim, Woong; Lee, Joonyeob; Lee, Changsoo; Hwang, Seokhwan

2017-12-01

Microbial community structure in a farm-scale anaerobic digester treating swine manure was investigated during three process events: 1) prolonged starvation, and changes of 2) operating temperature (between meso- and thermophilic) and 3) hydraulic retention time (HRT). Except during the initial period, the digester was dominated by hydrogenotrophic methanogens (HMs). The bacterial community structure significantly shifted with operating temperature and HRT but not with long-term starvation. Clostridiales (26.5-54.4%) and Bacteroidales (2.5-13.7%) became dominant orders in the digester during the period of HM dominance. Abundance of diverse meso- and thermophilic bacteria increased during the same period; many of these species may be H 2 producers, and/or syntrophic acetate oxidizers. Some of these species showed positive correlations with [NH 4 + -N] (p<0.1); this relationship suggests that ammonia was a significant parameter for bacterial selection. The bacterial niche information reported in this study can be useful to understand the ecophysiology of anaerobic digesters treating swine manure that contains high ammonia content. Copyright © 2017 Elsevier B.V. All rights reserved.

Potential of hydrolysis of particulate COD in extended anaerobic conditions to enhance biological phosphorous removal.

PubMed

Jabari, P; Yuan, Q; Oleszkiewicz, J A

2016-11-01

The effect of anaerobic hydrolysis of particulate COD (pCOD) on biological phosphorous removal in extended anaerobic condition was investigated through (i) sequencing batch reactors (SBR)s with anaerobic hydraulic retention time (HRT) of 0.8, 2, and 4 h; (ii) batch tests using biomass from a full scale biological nutrient removal (BNR) plant; and (iii) activated sludge modeling (BioWin 4.1 simulation). The results from long-term SBRs operation showed that phosphorus removal was correlated to the ratio of filtered COD (FCOD) to total phosphorus (TP) in the influent. Under conditions with low FCOD/TP ratio (average of 20) in the influent, extending anaerobic HRT to 4 h in the presence of pCOD did not significantly improve overall phosphorous removal. During the period with high FCOD/TP ratio (average of 37) in the influent, all SBRs removed phosphorous completely, and the long anaerobic HRT did not have negative effect on overall phosphorous removal. The batch tests also showed that pCOD at different concentration during 4 h test did not affect the rate of anaerobic phosphorus release. The rate of anaerobic hydrolysis of pCOD was significantly low and extending the anaerobic HRT was ineffective. The simulation (BioWin 4.1) of SBRs with low influent FCOD/TP ratio showed that the default kinetics of anaerobic hydrolysis in ASM2d overestimated phosphorous removal in the SBRs (high anaerobic hydrolysis of pCOD). The default anaerobic hydrolysis rate in BioWin 4.1 (ten times lower) could produce similar phosphorous removal to that in the experiment. Results showed that the current kinetics of anaerobic hydrolysis in ASM2d could lead to considerable error in predicting phosphorus removal in processes with extended anaerobic HRT. Biotechnol. Bioeng. 2016;113: 2377-2385. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Microbial Insight into a Pilot-Scale Enhanced Two-Stage High-Solid Anaerobic Digestion System Treating Waste Activated Sludge

PubMed Central

Wu, Jing; Cao, Zhiping; Hu, Yuying; Wang, Xiaolu; Wang, Guangqi; Zuo, Jiane; Wang, Kaijun; Qian, Yi

2017-01-01

High solid anaerobic digestion (HSAD) is a rapidly developed anaerobic digestion technique for treating municipal sludge, and has been widely used in Europe and Asia. Recently, the enhanced HSAD process with thermal treatment showed its advantages in both methane production and VS reduction. However, the understanding of the microbial community is still poor. This study investigated microbial communities in a pilot enhanced two-stage HSAD system that degraded waste activated sludge at 9% solid content. The system employed process “thermal pre-treatment (TPT) at 70 °C, thermophilic anaerobic digestion (TAD), and mesophilic anaerobic digestion (MAD)”. Hydrogenotrophic methanogens Methanothermobacter spp. dominated the system with relative abundance up to about 100% in both TAD and MAD. Syntrophic acetate oxidation (SAO) bacteria were discovered in TAD, and they converted acetate into H2 and CO2 to support hydrogenotrophic methanogenesis. The microbial composition and conversion route of this system are derived from the high solid content and protein content in raw sludge, as well as the operational conditions. This study could facilitate the understanding of the enhanced HSAD process, and is of academic and industrial importance. PMID:29189754

Present-day biogeochemical activities of anaerobic bacteria and their relevance to future exobiological investigations

USGS Publications Warehouse

Oremland, R.S.

1989-01-01

If the primordial atmosphere was reducing, then the first microbial ecosystem was probably composed of anaerobic bacteria. However, despite the presence of an oxygen-rich atmosphere, anaerobic habitats are important, commonplace components of the Earth's present biosphere. The geochemical activities displayed by these anaerobes impact the global cycling of certain elements (e.g., C, N, S, Fe, Mn, etc.). Methane provides an obvious example of how human-enhanced activities on a global scale can influence the content of a "radiative" (i.e., infrared absorbing) trace gas in the atmosphere. Methane can be oxidized by anaerobic bacteria, but this does not appear to support their growth. Acetylene, however, does support such growth. This may form the basis for future exobiological investigations of the atmospheres of anoxic, hydrocarbon-rich planets like Jupiter and Saturn, as well as the latter's satellite Titan. ?? 1989.

On-field study of anaerobic digestion full-scale plants (part I): an on-field methodology to determine mass, carbon and nutrients balance.

PubMed

Schievano, Andrea; D'Imporzano, Giuliana; Salati, Silvia; Adani, Fabrizio

2011-09-01

The mass balance (input/output mass flows) of full-scale anaerobic digestion (AD) processes should be known for a series of purposes, e.g. to understand carbon and nutrients balances, to evaluate the contribution of AD processes to elemental cycles, especially when digestates are applied to agricultural land and to measure the biodegradation yields and the process efficiency. In this paper, three alternative methods were studied, to determine the mass balance in full-scale processes, discussing their reliability and applicability. Through a 1-year survey on three full-scale AD plants and through 38 laboratory-scale batch digesters, the congruency of the considered methods was demonstrated and a linear equation was provided that allows calculating the wet weight losses (WL) from the methane produced (MP) by the plant (WL=41.949*MP+20.853, R(2)=0.950, p<0.01). Additionally, this new tool was used to calculate carbon, nitrogen, phosphorous and potassium balances of the three observed AD plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

A Comparative Study on Real Lab and Simulation Lab in Communication Engineering from Students' Perspectives

ERIC Educational Resources Information Center

Balakrishnan, B.; Woods, P. C.

2013-01-01

Over the years, rapid development in computer technology has engendered simulation-based laboratory (lab) in addition to the traditional hands-on (physical) lab. Many higher education institutions adopt simulation lab, replacing some existing physical lab experiments. The creation of new systems for conducting engineering lab activities has raised…

Kinematic Labs with Mobile Devices

NASA Astrophysics Data System (ADS)

Kinser, Jason M.

2015-07-01

This book provides 13 labs spanning the common topics in the first semester of university-level physics. Each lab is designed to use only the student's smartphone, laptop and items easily found in big-box stores or a hobby shop. Each lab contains theory, set-up instructions and basic analysis techniques. All of these labs can be performed outside of the traditional university lab setting and initial costs averaging less than 8 per student, per lab.

MethLAB

PubMed Central

Kilaru, Varun; Barfield, Richard T; Schroeder, James W; Smith, Alicia K

2012-01-01

Recent evidence suggests that DNA methylation changes may underlie numerous complex traits and diseases. The advent of commercial, array-based methods to interrogate DNA methylation has led to a profusion of epigenetic studies in the literature. Array-based methods, such as the popular Illumina GoldenGate and Infinium platforms, estimate the proportion of DNA methylated at single-base resolution for thousands of CpG sites across the genome. These arrays generate enormous amounts of data, but few software resources exist for efficient and flexible analysis of these data. We developed a software package called MethLAB (http://genetics.emory.edu/conneely/MethLAB) using R, an open source statistical language that can be edited to suit the needs of the user. MethLAB features a graphical user interface (GUI) with a menu-driven format designed to efficiently read in and manipulate array-based methylation data in a user-friendly manner. MethLAB tests for association between methylation and relevant phenotypes by fitting a separate linear model for each CpG site. These models can incorporate both continuous and categorical phenotypes and covariates, as well as fixed or random batch or chip effects. MethLAB accounts for multiple testing by controlling the false discovery rate (FDR) at a user-specified level. Standard output includes a spreadsheet-ready text file and an array of publication-quality figures. Considering the growing interest in and availability of DNA methylation data, there is a great need for user-friendly open source analytical tools. With MethLAB, we present a timely resource that will allow users with no programming experience to implement flexible and powerful analyses of DNA methylation data. PMID:22430798

Teachers' Perspectives on Online Virtual Labs vs. Hands-On Labs in High School Science

NASA Astrophysics Data System (ADS)

Bohr, Teresa M.

This study of online science teachers' opinions addressed the use of virtual labs in online courses. A growing number of schools use virtual labs that must meet mandated laboratory standards to ensure they provide learning experiences comparable to hands-on labs, which are an integral part of science curricula. The purpose of this qualitative case study was to examine teachers' perceptions of the quality and effectiveness of high school virtual labs. The theoretical foundation was constructivism, as labs provide student-centered activities for problem solving, inquiry, and exploration of phenomena. The research questions focused on experienced teachers' perceptions of the quality of virtual vs. hands-on labs. Data were collected through survey questions derived from the lab objectives of The Next Generation Science Standards . Eighteen teachers rated the degree of importance of each objective and also rated how they felt virtual labs met these objectives; these ratings were reported using descriptive statistics. Responses to open-ended questions were few and served to illustrate the numerical results. Many teachers stated that virtual labs are valuable supplements but could not completely replace hands-on experiences. Studies on the quality and effectiveness of high school virtual labs are limited despite widespread use. Comprehensive studies will ensure that online students have equal access to quality labs. School districts need to define lab requirements, and colleges need to specify the lab experience they require. This study has potential to inspire positive social change by assisting science educators, including those in the local school district, in evaluating and selecting courseware designed to promote higher order thinking skills, real-world problem solving, and development of strong inquiry skills, thereby improving science instruction for all high school students.

Enhancing post aerobic digestion of full-scale anaerobically digested sludge using free nitrous acid pretreatment.

PubMed

Wang, Qilin; Zhou, Xu; Peng, Lai; Wang, Dongbo; Xie, Guo-Jun; Yuan, Zhiguo

2016-05-01

Post aerobic digestion of anaerobically digested sludge (ADS) has been extensively applied to the wastewater treatment plants to enhance sludge reduction. However, the degradation of ADS in the post aerobic digester itself is still limited. In this work, an innovative free nitrous acid (HNO2 or FNA)-based pretreatment approach is proposed to improve full-scale ADS degradation in post aerobic digester. The post aerobic digestion was conducted by using an activated sludge to aerobically digest ADS for 4 days. Degradations of the FNA-treated (treated at 1.0 and 2.0 mg N/L for 24 h) and untreated ADSs were then determined and compared. The ADS was degraded by 26% and 32%, respectively, in the 4-day post aerobic digestion period while being pretreated at 1.0 and 2.0 mg HNO2-N/L. In comparison, only 20% of the untreated ADS was degraded. Economic analysis demonstrated that the implementation of FNA pretreatment can be economically favourable or not depending on the sludge transport and disposal cost. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biogas by semi-continuous anaerobic digestion of food waste.

PubMed

Zhang, Cunsheng; Su, Haijia; Wang, Zhenbin; Tan, Tianwei; Qin, Peiyong

2015-04-01

The semi-continuous anaerobic digestion of food waste was investigated in 1-L and 20-L continuously stirred tank reactors (CSTRs), to identify the optimum operation condition and the methane production of the semi-continuous anaerobic process. Results from a 1-L digester indicated that the optimum organic loading rate (OLR) for semi-continuous digestion is 8 g VS/L/day. The corresponding methane yield and chemical oxygen demand (COD) reduction were 385 mL/g VS and 80.2 %, respectively. Anaerobic digestion was inhibited at high OLRs (12 and 16 g VS/L/day), due to volatile fatty acid (VFA) accumulation. Results from a 20-L digester indicated that a higher methane yield of 423 mL/g VS was obtained at this larger scale. The analysis showed that the methane production at the optimum OLR fitted well with the determined kinetics equation. An obvious decrease on the methane content was observed at the initial of digestion. The increased metabolization of microbes and the activity decrease of methanogen caused by VFA accumulation explained the lower methane content at the initial of digestion.

Experimental and modelling studies on a laboratory scale anaerobic bioreactor treating mechanically biologically treated municipal solid waste.

PubMed

Lakshmikanthan, P; Sughosh, P; White, James; Sivakumar Babu, G L

2017-07-01

The performance of an anaerobic bioreactor in treating mechanically biologically treated municipal solid waste was investigated using experimental and modelling techniques. The key parameters measured during the experimental test period included the gas yield, leachate generation and settlement under applied load. Modelling of the anaerobic bioreactor was carried out using the University of Southampton landfill degradation and transport model. The model was used to simulate the actual gas production and settlement. A sensitivity analysis showed that the most influential model parameters are the monod growth rate and moisture. In this case, pH had no effect on the total gas production and waste settlement, and only a small variation in the gas production was observed when the heat transfer coefficient of waste was varied from 20 to 100 kJ/(m d K) -1 . The anaerobic bioreactor contained 1.9 kg (dry) of mechanically biologically treated waste producing 10 L of landfill gas over 125 days.

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

PubMed

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

2018-02-01

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

TangoLab-2 Card Troubleshooting

NASA Image and Video Library

2017-10-17

iss053e105442 (Oct. 17, 2017) --- Flight Engineer Mark Vande Hei swaps out a payload card from the TangoLab-1 facility and places into the TangoLab-2 facility. TangoLab provides a standardized platform and open architecture for experimental modules called CubeLabs. CubeLab modules may be developed for use in 3-dimensional tissue and cell cultures.

[Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

PubMed

Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

2015-09-01

The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium.

Improving anaerobic and aerobic degradation by ultrasonic disintegration of biomass.

PubMed

Neis, Uwe; Nickel, Klaus; Lundén, Anna

2008-11-01

Biological cell lysis is known to be the rate-limiting step of anaerobic biosolids degradation. Due to the slow pace by which this reaction occurs, it is necessary to equip treatment plants with large digesters or alternatively incorporate technological aids. High-power ultrasound used to disintegrate bacterial cells has been utilized as a pre-treatment process prior to anaerobic digestion. Through this application, as seen on pilot- and full-scales, it is possible to attain up to 30% more biogas, an increase in VS-destruction of up to 30% and a reduced sludge mass for disposal. Utilizing ultrasound technology in aerobic applications is a new and innovative approach. Improved denitrification through a more readily available internal carbon source, and less excess sludge mass can be traced to the positive effects that sonication of sludge has on the overall biological wastewater treatment process. Reference full-scale installations suggest that the technology is both technically feasible and economically sound.

Solar photocatalitycal treatment of carbofuran at lab and pilot scale: effect of classical parameters, evaluation of the toxicity and analysis of organic by-products.

PubMed

Lopez-Alvarez, Blady; Torres-Palma, Ricardo A; Peñuela, Gustavo

2011-07-15

In this work the TiO(2) solar-photocatalytical degradation of the pesticide carbofuran (CBF) in water, at lab and pilot scale, was studied. At lab scale the evaluation of CBF concentration (14-282 μmol L(-1)) showed that the system followed a Langmuir-Hinshelwood kinetics type. TiO(2) concentration (0.05-2 g L(-1)) and initial pH (3-9) were also evaluated and optimized using the surface response methodology and the Pareto diagram. In the range of variables studied, initial pH 7.60 and 1.43 g L(-1) of TiO(2) favoured the efficiency of the process. Under optimal conditions the evolution of substrate, chemical oxygen demand, dissolved organic carbon, toxicity and organics by-products were evaluated. In the pilot scale tests, using direct sunlight, 55 mg L(-1) of CBF in a commercial formulation was eliminated after 420 min; while after 900 min of treatment 80% of toxicity (1/E(50) on Vibrium Fischeri), 80% of chemical oxygen demand and 60% of dissolved organic carbon were removed. The analysis and evolution of five CBF by-products, as well the evaluation of the treatment in the presence of isopropanol or using acetonitrile as a solvent suggest that the degradation is mainly carried out by OH radical attack. Finally, a schema depicting the main degradation pathway is proposed. Copyright © 2011 Elsevier B.V. All rights reserved.

Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure

USDA-ARS?s Scientific Manuscript database

Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion, yet in temperate climate digesters, require a considerable amount of additional heat en...

A comparative study of thermophilic and mesophilic anaerobic co-digestion of food waste and wheat straw: Process stability and microbial community structure shifts.

PubMed

Shi, Xuchuan; Guo, Xianglin; Zuo, Jiane; Wang, Yajiao; Zhang, Mengyu

2018-05-01

Renewable energy recovery from organic solid waste via anaerobic digestion is a promising way to provide sustainable energy supply and eliminate environmental pollution. However, poor efficiency and operational problems hinder its wide application of anaerobic digestion. The effects of two key parameters, i.e. temperature and substrate characteristics on process stability and microbial community structure were studied using two lab-scale anaerobic reactors under thermophilic and mesophilic conditions. Both the reactors were fed with food waste (FW) and wheat straw (WS). The organic loading rates (OLRs) were maintained at a constant level of 3 kg VS/(m 3 ·d). Five different FW:WS substrate ratios were utilized in different operational phases. The synergetic effects of co-digestion improved the stability and performance of the reactors. When FW was mono-digested, both reactors were unstable. The mesophilic reactor eventually failed due to volatile fatty acid accumulation. The thermophilic reactor had better performance compared to mesophilic one. The biogas production rate of the thermophilic reactor was 4.9-14.8% higher than that of mesophilic reactor throughout the experiment. The shifts in microbial community structures throughout the experiment in both thermophilic and mesophilic reactors were investigated. With increasing FW proportions, bacteria belonging to the phylum Thermotogae became predominant in the thermophilic reactor, while the phylum Bacteroidetes was predominant in the mesophilic reactor. The genus Methanosarcina was the predominant methanogen in the thermophilic reactor, while the genus Methanothrix remained predominant in the mesophilic reactor. The methanogenesis pathway shifted from acetoclastic to hydrogenotrophic when the mesophilic reactor experienced perturbations. Moreover, the population of lignocellulose-degrading microorganisms in the thermophilic reactor was higher than those in mesophilic reactor, which explained the better

Kinetic study on the effect of temperature on biogas production using a lab scale batch reactor.

PubMed

Deepanraj, B; Sivasubramanian, V; Jayaraj, S

2015-11-01

In the present study, biogas production from food waste through anaerobic digestion was carried out in a 2l laboratory-scale batch reactor operating at different temperatures with a hydraulic retention time of 30 days. The reactors were operated with a solid concentration of 7.5% of total solids and pH 7. The food wastes used in this experiment were subjected to characterization studies before and after digestion. Modified Gompertz model and Logistic model were used for kinetic study of biogas production. The kinetic parameters, biogas yield potential of the substrate (B), the maximum biogas production rate (Rb) and the duration of lag phase (λ), coefficient of determination (R(2)) and root mean square error (RMSE) were estimated in each case. The effect of temperature on biogas production was evaluated experimentally and compared with the results of kinetic study. The results demonstrated that the reactor with operating temperature of 50°C achieved maximum cumulative biogas production of 7556ml with better biodegradation efficiency. Copyright © 2015 Elsevier Inc. All rights reserved.

A comparative study on real lab and simulation lab in communication engineering from students' perspectives

NASA Astrophysics Data System (ADS)

Balakrishnan, B.; Woods, P. C.

2013-05-01

Over the years, rapid development in computer technology has engendered simulation-based laboratory (lab) in addition to the traditional hands-on (physical) lab. Many higher education institutions adopt simulation lab, replacing some existing physical lab experiments. The creation of new systems for conducting engineering lab activities has raised concerns among educators on the merits and shortcomings of both physical and simulation labs; at the same time, many arguments have been raised on the differences of both labs. Investigating the effectiveness of both labs is complicated, as there are multiple factors that should be considered. In view of this challenge, a study on students' perspectives on their experience related to key aspects on engineering laboratory exercise was conducted. In this study, the Visual Auditory Read and Kinetic model was utilised to measure the students' cognitive styles. The investigation was done through a survey among participants from Multimedia University, Malaysia. The findings revealed that there are significant differences for most of the aspects in physical and simulation labs.

Metagenomic insights into the microbiota profiles and bioaugmentation mechanism of organics removal in coal gasification wastewater in an anaerobic/anoxic/oxic system by methanol.

PubMed

Xu, Weichao; Zhang, Yuxiu; Cao, Hongbin; Sheng, Yuxing; Li, Haibo; Li, Yuping; Zhao, He; Gui, Xuefei

2018-05-18

Coal gasification wastewater is a typical high phenol-containing, toxic and refractory industrial wastewater. Here, lab-scale anaerobic-anoxic-oxic system was employed to treat real coal gasification wastewater, and methanol was added to oxic tank as the co-substrate to enhance the removal of refractory organic pollutants. The results showed that the average COD removal in oxic effluent increased from 24.9% to 36.0% by adding methanol, the total phenols concentration decreased from 54.4 to 44.9 mg/L. GC-MS analysis revealed that contents of phenolic components and polycyclic aromatic hydrocarbons (PAHs) were decreased compared to the control and their degradation intermediates were observed. Microbial community revealed that methanol increased the abundance of phenolics and PAHs degraders such as Comamonas, Burkholderia and Sphingopyxis. Moreover, functional analysis revealed the relative abundance of functional genes associated with toluene, benzoate and PAHs degradation pathways was higher than that of control based on KEGG database. Copyright © 2018. Published by Elsevier Ltd.

Molecular and conventional analyses of microbial diversity in mesophilic and thermophilic upflow anaerobic sludge blanket granular sludges.

PubMed

Sekiguchi, Y; Kamagata, Y; Ohashi, A; Harada, H

2002-01-01

The microbial community structure of mesophilic (35 degrees C) and thermophilic (55 degrees C) methanogenic granular sludges was surveyed by using both cultivation-independent molecular approach and conventional cultivation technique in order to address the fundamental questions on the microbial populations, i.e. who are present, where they are located, and what they are doing there. To elucidate the microbial constituents within both sludges, we first constructed 16S ribosomal DNA clone libraries, and partial sequencing of the clones was conducted for phylogenetic analysis. In this experiment, we found a number of unidentifiable clones within the domain Bacteria as well as clones that were closely related with 16S rDNAs of cultured microbes. The unidentifiable clones accounted for approximately 60-70% of the total clones in both mesophilic and thermophilic libraries. 16S rRNA-targeted in situ hybridization combined with confocal laser scanning microscopy was subsequently employed to examine where the uncultured populations were located within sludge granules. Spatial organization of uncultured microbes was visualized in thin-sections of both types of granules using fluorescent oligonucleotide probes, which were designed based on the clone sequences of certain novel clusters. This resulted in the detection of two types of uncultured cells in specific locations inside the granules. Finally, the goal-directed conventional cultivation technique was employed to recover such uncultured anaerobes and uncover their physiology and functions. In this approach, a total of five new species of thermophilic microorganisms were isolated, including several types of syntrophs and a novel sugar-fermenting bacterium. In the previous molecular approaches, all of these isolates were suggested to be significant populations within thermophilic granular sludge, hence obtaining these isolates in pure culture decreased the fraction of unknown clones in the previous thermophilic clone

A Constructivist Cloud Lab.

ERIC Educational Resources Information Center

Emery, Dave

1996-01-01

Describes a lab involving a cloud formation activity that uses the constructivist learning model to get students more involved in creating the lab. Enables students to develop a greater understanding of the concepts involved and more interest in the lab's outcomes. (JRH)

Virtual Reality Lab Assistant

NASA Technical Reports Server (NTRS)

Saha, Hrishikesh; Palmer, Timothy A.

1996-01-01

Virtual Reality Lab Assistant (VRLA) demonstration model is aligned for engineering and material science experiments to be performed by undergraduate and graduate students in the course as a pre-lab simulation experience. This will help students to get a preview of how to use the lab equipment and run experiments without using the lab hardware/software equipment. The quality of the time available for laboratory experiments can be significantly improved through the use of virtual reality technology.

Anaerobic hydrogen production with an efficient carrier-induced granular sludge bed bioreactor.

PubMed

Lee, Kuo-Shing; Wu, Ji-Fang; Lo, Yung-Sheng; Lo, Yung-Chung; Lin, Ping-Jei; Chang, Jo-Shu

2004-09-05

A novel bioreactor containing self-flocculated anaerobic granular sludge was developed for high-performance hydrogen production from sucrose-based synthetic wastewater. The reactor achieved an optimal volumetric hydrogen production rate of approximately 7.3 L/h/L (7,150 mmol/d/L) and a maximal hydrogen yield of 3.03 mol H2/mol sucrose when it was operated at a hydraulic retention time (HRT) of 0.5 h with an influent sucrose concentration of 20 g COD/L. The gas-phase hydrogen content and substrate conversion also exceeded 40 and 90%, respectively, under optimal conditions. Packing of a small quantity of carrier matrices on the bottom of the upflow reactor significantly stimulated sludge granulation that can be accomplished within 100 h. Among the four carriers examined, spherical activated carbon was the most effective inducer for granular sludge formation. The carrier-induced granular sludge bed (CIGSB) bioreactor was started up with a low HRT of 4-8 h (corresponding to an organic loading rate of 2.5-5 g COD/h/L) and enabled stable operations at an extremely low HRT (up to 0.5 h) without washout of biomass. The granular sludge was rapidly formed in CIGSB supported with activated carbon and reached a maximal concentration of 26 g/L at HRT = 0.5 h. The ability to maintain high biomass concentration at low HRT (i.e., high organic loading rate) highlights the key factor for the remarkable hydrogen production efficiency of the CIGSB processes.

Performance of sequential anaerobic/aerobic digestion applied to municipal sewage sludge.

PubMed

Tomei, M Concetta; Rita, Sara; Mininni, Giuseppe

2011-07-01

A promising alternative to conventional single phase processing, the use of sequential anaerobic-aerobic digestion, was extensively investigated on municipal sewage sludge from a full scale wastewater treatment plant. The objective of the work was to evaluate sequential digestion performance by testing the characteristics of the digested sludge in terms of volatile solids (VS), Chemical Oxygen Demand (COD) and nitrogen reduction, biogas production, dewaterability and the content of proteins and polysaccharides. VS removal efficiencies of 32% in the anaerobic phase and 17% in the aerobic one were obtained, and similar COD removal efficiencies (29% anaerobic and 21% aerobic) were also observed. The aerobic stage was also efficient in nitrogen removal providing a decrease of the nitrogen content in the supernatant attributable to nitrification and simultaneous denitrification. Moreover, in the aerobic phase an additional marked removal of proteins and polysaccharides produced in the anaerobic phase was achieved. The sludge dewaterability was evaluated by determining the Optimal Polymer Dose (OPD) and the Capillary Suction Time (CST) and a significant positive effect due to the aerobic stage was observed. Biogas production was close to the upper limit of the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days. From a preliminary analysis it was found that the energy demand of the aerobic phase was significantly lower than the recovered energy in the anaerobic phase and the associated additional cost was negligible in comparison to the saving derived from the reduced amount of sludge to be disposed. Copyright © 2011 Elsevier Ltd. All rights reserved.

A new hydrodynamic prediction of the peak heat flux from horizontal cylinders in low speed upflow

NASA Technical Reports Server (NTRS)

Ungar, E. K.; Eichhorn, R.

1988-01-01

Flow-boiling data have been obtained for horizontal cylinders in saturated acetone, isopropanol, and water, yielding heat flux vs. wall superheat boiling curves for the organic liquids. A region of low speed upflow is identified in which long cylindrical bubbles break off from the wake with regular frequency. The Strouhal number of bubble breakoff is a function only of the Froude number in any liquid, and the effective wake thickness in all liquids is a function of the density ratio and the Froude number. A low speed flow boiling burnout prediction procedure is presented which yields accurate results in widely dissimilar liquids.

Livestock Anaerobic Digester Database

EPA Pesticide Factsheets

The Anaerobic Digester Database provides basic information about anaerobic digesters on livestock farms in the United States, organized in Excel spreadsheets. It includes projects that are under construction, operating, or shut down.

Nutrients recovery from anaerobic digestate of agro-waste: Techno-economic assessment of full scale applications.

PubMed

Bolzonella, D; Fatone, F; Gottardo, M; Frison, N

2018-06-15

The sustainable production of fertilizers, especially those based on phosphorus, will be one of the challenges of this century. Organic wastes produced by the agriculture, urban and industrial sectors are rich in nutrients which can be conveniently recovered and used as fertilizers. In this study five full scale systems for the recovery of nutrients from anaerobic digestate produced in farm-scale plants were studied. Monitored technologies were: drying with acidic recovery, stripping with acidic recovery and membrane separation. Results showed good performances in terms of nutrients recovery with average yields always over 50% for both nitrogen and phosphorus. The techno-economic assessment showed how the specificity of the monitored systems played a major role: in particular, membranes were able to produce a stream of virtually pure water (up to 50% of the treated digestate) reducing the digestate volume, while drying, because of the limitation on recoverable heat, could treat only a limited portion (lower than 50%) of produced digestate while stripping suffered some problems because of the presence of suspended solids in the liquid fraction treated. Specific capital and operational costs for the three systems were comparable ranging between 5.40 and 6.97 € per m 3 of digestate treated and followed the order stripping > drying > membranes. Costs determined in this study were similar to those observed in other European experiences reported in literature. Copyright © 2017 Elsevier Ltd. All rights reserved.

Observation of Flame Stabilized at a Hydrogen-Turbojet-Engine Injector Installed into a Lab-Scale Combustion Wind Tunnel

NASA Astrophysics Data System (ADS)

Michishita, Kazutaka; Nomura, Hiroshi; Ujiie, Yasushige; Okai, Keiichi

A lab-scale combustion wind tunnel was developed for investigation of low-pressure ignition and flame holding in a sub-scale pre-cooled turbojet engine with hydrogen fuel in order to make engine start at high altitudes sure. The combustion wind tunnel is a blow-down type. A fuel injector of the sub-scale pre-cooled turbojet engine was installed into the combustion wind tunnel. Conditions in which a flame can be stabilized at the fuel injector were examined. The combustor pressure and equivalence ratio were varied from 10 to 40 kPa and from 0.4 to 0.8, respectively. The mean inlet air velocity was varied from 2 to 48 m/s. Flames stabilized at 20 kPa in pressure and 0.6 in equivalence ratio were observed. It was found that the decrease in the combustor pressure narrows the mean inlet air velocity range for successful flame holdings. Flame holding at lower combustor pressures is realized at the equivalence ratio of 0.4 in the low mean inlet air velocity range, and at the equivalence ratio of 0.6 in the high mean inlet air velocity range. Flame luminosity is the largest near the fuel injector. The flame luminosity distribution becomes flatter as the increase in the mean inlet air velocity.

Utilization of vegetable dumplings waste from industrial production by anaerobic digestion

NASA Astrophysics Data System (ADS)

Pilarska, Agnieszka A.; Pilarski, Krzysztof; Ryniecki, Antoni; Tomaszyk, Kamila; Dach, Jacek; Wolna-Maruwka, Agnieszka

2017-01-01

This paper provides the analysis of results of biogas and methane yield for vegetable dumplings waste: dough with fat, vegetable waste, and sludge from the clarifier. Anaerobic digestion of food waste used in the experiments was stable after combining the substrates with a digested pulp composed of maize silage and liquid manure (as inoculum), at suitable ratios. The study was carried out in a laboratory scale using anaerobic batch reactors, at controlled (mesophilic) temperature and pH conditions. The authors present the chemical reactions accompanying biodegradation of the substrates and indicate the chemical compounds which may lead to acidification during the anaerobic digestion. An anaerobic digestion process carried out with the use of a dough-and-fat mixture provided the highest biogas and methane yields. The following yields were obtained in terms of fresh matter: 242.89 m3 Mg-1 for methane and 384.38 m3 Mg-1 for biogas, and in terms of volatile solids: 450.73 m3 Mg-1 for methane and 742.40 m3 Mg-1 for biogas. Vegetables and sludge from the clarifier (as fresh matter) provided much lower yields.

LabSkills

ERIC Educational Resources Information Center

O'Brien, Nick

2010-01-01

This article describes LabSkills, a revolutionary teaching tool to improve practical science in schools. LabSkills offers the chance to help improve the exposure that the average Key Stage 5 (age 16-19) student has to practical work. This is a huge area for development being highlighted by universities who are seeing a worryingly growing trend in…

Large-scale horizontal flows from SOUP observations of solar granulation

NASA Technical Reports Server (NTRS)

November, L. J.; Simon, G. W.; Tarbell, T. D.; Title, A. M.; Ferguson, S. H.

1987-01-01

Using high resolution time sequence photographs of solar granulation from the SOUP experiment on Spacelab 2, large scale horizontal flows were observed in the solar surface. The measurement method is based upon a local spatial cross correlation analysis. The horizontal motions have amplitudes in the range 300 to 1000 m/s. Radial outflow of granulation from a sunspot penumbra into surrounding photosphere is a striking new discovery. Both the supergranulation pattern and cellular structures having the scale of mesogranulation are seen. The vertical flows that are inferred by continuity of mass from these observed horizontal flows have larger upflow amplitudes in cell centers than downflow amplitudes at cell boundaries.

Large-scale horizontal flows from SOUP observations of solar granulation

NASA Astrophysics Data System (ADS)

November, L. J.; Simon, G. W.; Tarbell, T. D.; Title, A. M.; Ferguson, S. H.

1987-09-01

Using high-resolution time-sequence photographs of solar granulation from the SOUP experiment on Spacelab 2 the authors observed large-scale horizontal flows in the solar surface. The measurement method is based upon a local spatial cross correlation analysis. The horizontal motions have amplitudes in the range 300 to 1000 m/s. Radial outflow of granulation from a sunspot penumbra into the surrounding photosphere is a striking new discovery. Both the supergranulation pattern and cellular structures having the scale of mesogranulation are seen. The vertical flows that are inferred by continuity of mass from these observed horizontal flows have larger upflow amplitudes in cell centers than downflow amplitudes at cell boundaries.

Assessment of Subjective Perceived Exertion at the Anaerobic Threshold with the Borg CR-10 Scale.

PubMed

Zamunér, Antonio R; Moreno, Marlene A; Camargo, Taís M; Graetz, Juliana P; Rebelo, Ana C S; Tamburús, Nayara Y; da Silva, Ester

2011-01-01

The purpose of this study was to evaluate the anaerobic threshold (AT) with a graphic visual method for estimating the intensity of ventilatory and metabolic exertion and to determine the ratings of perceived exertion (RPE) on the Borg CR-10 scale during a continuous ramp type exercise test (CT-R). Forty healthy, physically active and sedentary young women (age 23.1 ± 3.52 years) were divided into two groups according to their fitness level: active group (AG) and sedentary group (SG) and were submitted to a CT-R on a cycloergometer with 20 to 25 W/min increments. Shortly before the end of each one-minute period, the subjects were asked to rate dyspnea (RPE-D) and leg fatigue (RPE-L) on the Borg CR-10 scale. After the AT was determined with the graphic visual method, the score that the volunteers gave on the Borg CR10 scale was verified. Data were analyzed using the Mann-Whitney and Spearman correlation tests with the significance level set at 5%. The mean ratings of RPE-L and RPE-D at the AT level were not significantly different between groups (p > 0.05). Significant correlations were found between VO2, heart rate (HR), power output and RPE for both groups. The muscular and respiratory RPE, according to the Borg CR-10 scale, were correlated with the AT, suggesting that scores close to 5, which correspond to a "strong" perception, may be used as parameters for quantifying aerobic exercise intensity for active and sedentary individuals. The similar perception of exercise intensity, which corresponded to the AT of different individuals, makes it possible to prescribe exercise at an intensity equivalent to the AT by means of the RPE. Key pointsInterest in quantitative and systematic determination of the AT is growing, however, qualitative studies measure the AT by perceived exertion, are still unsubstantial.Borg CR-10 scale is a category scale with ratio properties consisting of numbers related to verbal expressions, which allows rate comparison between intensities

High rate mesophilic, thermophilic, and temperature phased anaerobic digestion of waste activated sludge: A pilot scale study

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

Bolzonella, David, E-mail: david.bolzonella@univr.it; Cavinato, Cristina, E-mail: cavinato@unive.it; Fatone, Francesco, E-mail: francesco.fatone@univr.it

2012-06-15

Highlights: Black-Right-Pointing-Pointer High temperatures were tested in single and two-stage anaerobic digestion of waste activated sludge. Black-Right-Pointing-Pointer The increased temperature demonstrated the possibility of improving typical yields of the conventional mesophilic process. Black-Right-Pointing-Pointer The temperature phased anaerobic digestion process (65 + 55 Degree-Sign C) showed the best performances with yields of 0.49 m{sup 3}/kgVS{sub fed}. Black-Right-Pointing-Pointer Ammonia and phosphate released from solids destruction determined the precipitation of struvite in the reactor. - Abstract: The paper reports the findings of a two-year pilot scale experimental trial for the mesophilic (35 Degree-Sign C), thermophilic (55 Degree-Sign C) and temperature phased (65 +more » 55 Degree-Sign C) anaerobic digestion of waste activated sludge. During the mesophilic and thermophilic runs, the reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 20 days. In the temperature phased run, the first reactor operated at an organic loading rate of 15 kgVS/m{sup 3}d and a hydraulic retention time of 2 days while the second reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 18 days (20 days for the whole temperature phased system). The performance of the reactor improved with increases in temperature. The COD removal increased from 35% in mesophilic conditions, to 45% in thermophilic conditions, and 55% in the two stage temperature phased system. As a consequence, the specific biogas production increased from 0.33 to 0.45 and to 0.49 m{sup 3}/kgVS{sub fed} at 35, 55, and 65 + 55 Degree-Sign C, respectively. The extreme thermophilic reactor working at 65 Degree-Sign C showed a high hydrolytic capability and a specific yield of 0.33 gCOD (soluble) per gVS{sub fed}. The effluent of the extreme thermophilic reactor showed an average concentration of soluble COD and

Anaerobic muscle strengthening physical activity and depression severity among USA adults.

PubMed

Cangin, Causenge; Harris, Randall; Binkley, Philip; Schwartzbaum, Judith; Focht, Brian

2018-06-01

We investigated the association between depression and anaerobic physical activity (while controlling aerobic physical activity), using a nationally representative sample of USA adults ( n  = 7354) who participated in the cross sectional National Health and Nutrition Examination Survey (NHANES, 1999-2006). We defined depression using the validated "Patient Health Questionnaire" (PHQ 9 ) scale of 0-27 as PHQ 9   ≥  10. Severity of depression was classified by clinically established PHQ 9 levels: mild (5-9), dysthymic (10-14), moderate (15-19), and major depression ( ≥ 20). We used logistic regression to estimate adjusted odds ratios of depression associated with distinct types of activity (only aerobic, only anaerobic, combined regime). We used multinomial logistic regression to examine associations of anaerobic activity with various severity levels of depression (mild, dysthymic, moderate, and major depression) with adjustment for aerobic activity. Women had higher prevalence of depression than men (8.4% versus 5.7%), whereas anaerobic muscle strengthening activity was more common in men than women (35% versus 24%). Adjusting for aerobic activity , anaerobic activity was inversely associated with depression (PHQ 9   ≥  10) in women under 50 (OR = 0.57; 95%CI = 0.41-0.81), all women (OR = 0.59; 0.43-0.80), men under 50 (OR = 0.85; 0.58-1.2), and all men (OR = 0.72; 0.51-1.01). Anaerobic activity was inversely associated with severity level of depressive symptoms in women and men. The combined regimen of anaerobic muscle strengthening activity and meeting the Physical Activity Guideline for America (PAGA) was related to the lowest odds ratio of depression in women (OR = 0.50; 95%CI = 0.33-0.75) and men (OR = 0.39; 95%CI = 0.23-0.62). Independent of aerobic physical activity, anaerobic muscle strengthening activity is significantly and inversely associated with depression among USA adults.

Economic viability of anaerobic digestion

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

Wellinger, A.

1996-01-01

The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs ofmore » an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.« less

Methane and hydrogen sulfide production during co-digestion of forage radish and dairy manure

USDA-ARS?s Scientific Manuscript database

Forage radish cover crops were investigated as a co-substrate to increase biogas production from dairy manure-based anaerobic digestion. Lab-scale batch digesters (300 mL) were operated under mesophilic conditions during two experiments. In the first experiment, the optimal co-digestion ratio for ...

Development of image analysis techniques as a tool to detect and quantify morphological changes in anaerobic sludge: I. Application to a granulation process.

PubMed

Araya-Kroff, P; Amaral, A L; Neves, L; Ferreira, E C; Pons, M-N; Mota, M; Alves, M M

2004-07-20

Image analysis techniques were developed and applied to quantify the process of anaerobic granulation in an expanded granular sludge blanket reactor (EGSB) fed with a synthetic substrate based on glucose [60-30% COD (chemical oxygen demand)] and volatile fatty acids (40-70% COD) over 376 days. In a first operation period that lasted 177 days, the aggregation of dispersed sludge was quantitatively monitored through the recognition and quantification of aggregates and filaments. A parameter defined as the ratio between the filaments' length and the aggregates projected area (LfA) has proven to be sensitive to detect changes in the aggregation status of the anaerobic sludge. The aggregation time-defined as the moment when a balance between filaments' length and aggregates' size was established-was recognized through the LfA. The percentage of projected area of aggregates within three size ranges (0.01-0.1 mm, 0.1-1 mm, and >1 mm, equivalent diameter) reflected the granular size spectrum during the aggregation process. When sudden increases on the upflow velocity and on the organic loading rate were applied to the previously formed granules, the developed image analysis techniques revealed to be good indicators of granular sludge stability, since they were sensitive to detected filaments release, fragmentation, and erosion that usually leads to washout. The specific methanogenic activities in the presence of acetate, propionate, butyrate, and H(2)/CO(2) increased along the operation, particularly relevant was the sudden increase in the specific hydrogenophilic activity, immediately after the moment recognized as aggregation time. Copyright 2004 Wiley Periodicals, Inc.

The national labs and their future

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

Crease, R.P.

National laboratories of the USA, born with the atomic age and raised to prominence by the need for scientific superiority during the long Cold War, are facing the most critical challenge: how best to support the nation's current need to improve its international competitiveness through superior technology The charge that the national laboratories are [open quotes]Cold War relics[close quotes] that have outlived their usefulness is based on a misunderstanding of their mission, says Robert P. Crease, historian for Brookhaven National laboratory. Three of the labs-Los Alamos, Sandia, and Lawrence Livermore- are weapons laboratories and their missions must change. Oak Ridge,more » Argonne, and Brookhaven laboratories are multipurpose: basic research facilities with a continuing role in the world of science The national laboratory system traces its origins to the Manhattan Project. Over the next half-century, America's national labs grew into part of the most effective scientific establishment in the world, a much-copied model for management of large-scale scientific programs. In the early years, each lab defined a niche in the complex world of reactors, accelerators, and high-energy proton and electron physics. In the 1970s, several labs worked on basic energy sciences to help solve a national energy crisis. Today, the labs are pressured to do more applied research-research to transfer to the private sector and will have to respond by devising more effective ways of coordinating basic and applied research. But, Crease warns, [open quotes]It also will be essential that any commitment to applied research not take place at the cost of reducing the wellspring of basic research from which so much applied research flows. [open quotes]Making a solid and persuasive case for the independent value of basic research, and for their own role in that enterprise, may be the most important task facing the laboratories in their next half-century,[close quotes].« less