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Chen S, Wang M, Wu M, Lu Y, Fu A, Gobler CJ, Asato C, Mao X. Greenhouse gas emission and denitrification kinetics of woodchip bioreactors treating onsite wastewater. WATER RESEARCH 2024; 268:122562. [PMID: 39393179 DOI: 10.1016/j.watres.2024.122562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2024] [Revised: 09/16/2024] [Accepted: 09/30/2024] [Indexed: 10/13/2024]
Abstract
The accurate evaluation of denitrification rate and greenhouse gas (GHG) emission in field-scale woodchip bioreactors for onsite wastewater treatment are problematic due to inevitably varied environmental conditions and underestimated GHG production with limited analysis of dissolved gas in field samples. To address these problems, batch incubation experiments were conducted with controlled conditions to precisely evaluate the denitrification kinetics and N2O and CH4 emission of both gaseous and dissolved phases in fresh (6 months) and aged (5 years) woodchip bioreactors treating onsite wastewater at high (1-3 mg L-1) and no (0 mg L-1) dissolved oxygen (DO) levels. NO3- removal rate decreased from 37.5-119.0 g NO3--N m-3d-1 at no DO to 8.8-16.6 g NO3--N m-3d-1 at high DO (1-3 mg L-1) due to the growth suppression of NO2- reducing microorganisms (37-55 % lower nirS+nirK abundance). However, the presence of high DO increased N2O emission level from 5.6-6.9 mg N2ON m-3 at no DO to 179.5-273.6 mg N2ON m-3) due to the enhanced growth of NO reducing microorganisms (1-7 times higher norB levels) and the decreased abundance of N2O reducing microorganisms (53-75 % lower nosZ abundance). On the other hand, increased DO level negatively correlated with CH4 production (1.0-3.9 g CH4-C m-3d-1) in fresh woodchips, while showed insignificant impact on CH4 production (0.1-1.4 g CH4-C m-3d-1) in aged woodchips. Woodchip age increase (5 years) negatively impacted the NO3- removal rate (75-85 % lower than fresh woodchips) and CH4 production rate (>3 times lower than fresh woodchips), probably due to the reduced biomass density of NO2- reducing microorganisms (52-58 % lower nirS+nirK abundance) and methanogens (95-98 % lower mcrA levels). The incubation results suggested that long hydraulic retention time (>2-5 days) and anaerobic/anoxic condition are preferred for the optimal NO3- removal and low N2O emission potential of woodchip bioreactors treating onsite wastewater.
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Affiliation(s)
- Siwei Chen
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY, 11794, United States; New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, United States
| | - Mian Wang
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY, 11794, United States; New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, United States
| | - Maggie Wu
- William A. Shine Great Neck South High School, Lake Success, NY, 11020, United States
| | - Yuhang Lu
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY, 11794, United States; New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, United States
| | - Ao Fu
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY, 11794, United States
| | - Christopher J Gobler
- New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, United States; School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY, 11794, United States
| | - Caitlin Asato
- New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, United States
| | - Xinwei Mao
- Department of Civil Engineering, Stony Brook University, Stony Brook, NY, 11794, United States; New York State Center for Clean Water Technology, Stony Brook University, Stony Brook, NY, 11794, United States.
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Li C, Xue C, Ouyang W, Liu M, Sun Y, Liu H. Identification and synergetic mechanism of TCE, H 2 and O 2 metabolic microorganisms in the joint H 2/O 2 system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:163026. [PMID: 36965730 DOI: 10.1016/j.scitotenv.2023.163026] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/19/2023] [Accepted: 03/19/2023] [Indexed: 05/17/2023]
Abstract
The sole H2 and O2 usually promote chlorinated hydrocarbons (CHCs) biotransformation by several mechanisms, including reductive dechlorination and aerobic oxidation. However, the mechanism of the CHCs transformation in joint H2 and O2 system (H2/O2 system) is still unclear. In this study, the degradation kinetics of trichloroethene (TCE) were investigated and DNA stable isotope probing (DNA-SIP) were used to explore the synergistic mechanism of functional microorganisms on TCE degradation under the condition of H2/O2 coexistence. In the H2/O2 microcosm, TCE was significantly removed by 13.00 μM within 40 days, much higher than N2, H2 and O2 microcosms, and 1,1-DCE was detected as an intermediate. DNA-SIP technology identified three anaerobic TCE metabolizers, five aerobic TCE metabolizers, nine hydrogen-oxidizing bacteria (HOB), some TCE metabolizers utilizing limited O2, and some anaerobic dechlorinating bacteria reductively using H2 to dechlorinate TCE. It is also confirmed for the first time that 3 OUTs belonging to Methyloversatilis and SH-PL14 can simultaneously utilize H2 and O2 as energy sources to grow and metabolize TCE or 1,1-DCE. HOB may provide carbon sources or electron acceptors or donors for TCE biotransformation. These findings confirm the coexistence of anaerobic and aerobic TCE metabolizers and degraders, which synergistically promoted the conversion of TCE in the joint H2/O2 system. Our results provide more information about the functional microbe resources and synergetic mechanisms for TCE degradation.
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Affiliation(s)
- Cui Li
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430078, PR China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei 430078, PR China
| | - Chen Xue
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430078, PR China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei 430078, PR China
| | - Weiwei Ouyang
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430078, PR China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei 430078, PR China
| | - Minghui Liu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430078, PR China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei 430078, PR China
| | - Yingtao Sun
- State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong 510640, PR China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing 100049, PR China
| | - Hui Liu
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan, Hubei 430078, PR China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei 430078, PR China.
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Stein N, Podder A, Goel R. Biodegradation of insensitive munition (IM) formulations: IMX-101 and IMX-104 using aerobic granule technology. JOURNAL OF HAZARDOUS MATERIALS 2023; 449:130942. [PMID: 36801711 DOI: 10.1016/j.jhazmat.2023.130942] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/15/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
A laboratory-scale aerobic granular sludge (AGS) sequencing batch bioreactor (SBR) was initiated in this study for the biodegradation of hazardous insensitive munition (IM) formulation constituents; 2,4-dinitroanisole (DNAN), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 1-nitroguanidine (NQ), and 3-nitro-1,2,4-triazol-5-one (NTO). Efficient (bio)transformation of the influent DNAN and NTO was achieved throughout reactor operation with removal efficiencies greater than 95%. An average removal efficiency of 38.4 ± 17.5% was recorded for RDX. NQ was only slightly removed (3.96 ± 4.15%) until alkalinity was provided in the influent media, which subsequently increased the NQ removal efficiency up to an average of 65.8 ± 24.4%. Batch experiments demonstrated a competitive advantage for aerobic granular biofilms over flocculated biomass for the (bio)transformation DNAN, RDX, NTO, and NQ, as aerobic granules were capable of reductively (bio)transforming each IM compound under bulk aerobic conditions while flocculated biomass could not, thus demonstrating the contribution of inner oxygen-free zones within aerobic granules. A variety of catalytic enzymes were identified in the extracellular polymeric matrix of the AGS biomass. 16 S rDNA amplicon sequencing found Proteobacteria (27.2-81.2%) to be the most abundant phyla, with many genera associated with nutrient removal as well as genera previously described in relation to the biodegradation of explosives or related compounds.
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Affiliation(s)
- Nathan Stein
- Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Ramesh Goel
- Department of Civil and Environmental Engineering, University of Utah, Salt Lake City, UT 84112, USA.
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Fu S, Lian S, Angelidaki I, Guo R. Micro-aeration: an attractive strategy to facilitate anaerobic digestion. Trends Biotechnol 2022; 41:714-726. [PMID: 36216713 DOI: 10.1016/j.tibtech.2022.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/13/2022] [Accepted: 09/19/2022] [Indexed: 01/11/2023]
Abstract
Micro-aeration can facilitate anaerobic digestion (AD) by regulating microbial communities and promoting the growth of facultative taxa, thereby increasing methane yield and stabilizing the AD process. Additionally, micro-aeration contributes to hydrogen sulfide stripping by oxidization to produce molecular sulfur or sulfuric acid. Although micro-aeration can positively affect AD, it must be strictly regulated to maintain an overall anaerobic environment that permits anaerobic microorganisms to thrive. Even so, obligate anaerobes, especially methanogens, could suffer from oxidative stress during micro-aeration. This review describes the applications of micro-aeration in AD and examines the cutting-edge advances in how methanogens survive under oxygen stress. Moreover, barriers and corresponding solutions are proposed to move micro-aeration technology closer to application at scale.
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Key parameters influencing hydrogen sulfide removal in microaerobic sequencing batch reactor. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.107951] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Sousa MR, Oliveira CJS, Carneiro JM, Lopes AC, Rodríguez E, Vasconcelos EAF, Holanda GBM, Landim PGC, Silva MER, Firmino PIM, Dos Santos AB. Evaluation of different air dosing strategies to enhance H 2S removal in microaerobic systems treating low-strength wastewaters. ENVIRONMENTAL TECHNOLOGY 2019; 40:3724-3734. [PMID: 29888986 DOI: 10.1080/09593330.2018.1487470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 05/30/2018] [Indexed: 06/08/2023]
Abstract
This study aimed to evaluate different air dosing strategies such as microaeration flow rates and air dosing points to enhance H2S removal in microaerobic systems treating low-strength wastewaters. Efficiency and stability of the reactors, as well as biogas quality, were assessed, and microbial community changes were evaluated using the PCR-DGGE technique. The results showed that the air dosing point affected the H2S concentration and that air dosing at the headspace promoted the highest H2S removal efficiency. The airflow rate also affected the process, since H2S concentration in the biogas was higher at 0.1 mL air.min-1 than at 0.3 mL air.min-1. The methane concentration in the biogas was also affected by both air dosing point and flow rate, since the lowest value was observed at the highest airflow rate of the headspace dosing point, due to dilution by the N2 influx applied to the system. The highest productivity and operational efficiency were observed at this air dosing point, with this airflow (HD0.3), which corroborates with the operational results and the ecological parameters, since the microaeration at this stage promoted high bacterial and archaeal species richness and diversity, optimum functional organization, high COD and H2S removal efficiencies.
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Affiliation(s)
- M R Sousa
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - C J S Oliveira
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - J M Carneiro
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - A C Lopes
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - E Rodríguez
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - E A F Vasconcelos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - G B M Holanda
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - P G C Landim
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - M E R Silva
- Department of Civil Construction, Federal Institute of Science and Technology of Ceará, Fortaleza, Ceará, Brazil
| | - P I M Firmino
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | - A B Dos Santos
- Department of Hydraulic and Environmental Engineering, Federal University of Ceará, Fortaleza, Ceará, Brazil
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Tabla-Hernandez J, Lopez-Galvan E. Effect of packing material on organic matter removal efficiency in an anaerobic-aerobic baffled bioreactor. ENVIRONMENTAL TECHNOLOGY 2018; 39:1032-1040. [PMID: 28406061 DOI: 10.1080/09593330.2017.1319423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Accepted: 04/08/2017] [Indexed: 06/07/2023]
Abstract
The aim of the present work was to study the effect of packing material on the organic matter removal efficiency (OMRE) in an anaerobic-aerobic baffled bioreactor (AAB). For this purpose, two different experiments were conducted with two types of packing material: activated carbon (AC) particles and polyurethane foam (PF). The system consisted of two treatments; the first one was anaerobic, where hydrolysis, acetogenesis and methanogenesis took place. In anaerobic chambers, there were no packing materials and the operating conditions were the same in both experiments. The second treatment was aerobic and both materials were placed at different times as a bedding. The parameters measured were chemical oxygen demand (COD), dissolved chemical oxygen demand (CODd), total organic carbon (TOC), nitrate concentration (NO3-), ammonium concentration (NH4+), electric conductivity (σ), alkalinity (Alky) and hydrogen potential (pH). Paired t-Student test showed that there was no significant difference in the OMRE in anaerobic treatment, whereas there was in aerobic treatment, due to the effect of packing material. NH4+ and NO3- showed a negative Pearson correlation in both experiments, indicating the presence of the nitrification process in the aerobic chamber. AAB packed with PF had better performance at obtaining an OMRE of around 63%, whereas AAB packed with AC presented an OMRE of around 51%.
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Affiliation(s)
- Jacobo Tabla-Hernandez
- a Departamento de ciencias básicas e ingeniería, Dirección de Ciencia Básicas e Ingeniería , Universidad Autónoma Metropolitana , Ciudad de México , México
- b Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente y Desarrollo (CIIEMAD), Instituto Politécnico Nacional (IPN) , Ciudad de México , México
| | - Edgar Lopez-Galvan
- c Departamento de Recursos de la Tierra, Dirección de Ciencia Básicas e Ingeniería , Universidad Autónoma Metropolitana , Lerma de Villada , Estado de México , México
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Pokorna-Krayzelova L, Mampaey KE, Vannecke TP, Bartacek J, Jenicek P, Volcke EI. Model-based optimization of microaeration for biogas desulfurization in UASB reactors. Biochem Eng J 2017. [DOI: 10.1016/j.bej.2017.06.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Krohn J, Lozanovska I, Kuzyakov Y, Parvin S, Dorodnikov M. CH 4 and CO 2 production below two contrasting peatland micro-relief forms: An inhibitor and δ 13C study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 586:142-151. [PMID: 28169027 DOI: 10.1016/j.scitotenv.2017.01.192] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/24/2017] [Accepted: 01/27/2017] [Indexed: 06/06/2023]
Abstract
Two peatland micro-relief forms (microforms) - hummocks and hollows - differ by their hydrological characteristics (water table level, i.e. oxic-anoxic conditions) and vegetation communities. We studied the CH4 and CO2 production potential and the localization of methanogenic pathways in both hummocks and hollows at depths of 15, 50, 100, 150 and 200cm in a laboratory incubation experiment. For this purpose, we measured CH4 and CO2 production rates, peat elemental composition, as well as δ13C values of gases and solids; the specific inhibitor of methanogenesis BES (2-bromo-ethane sulfonate, 1mM) was aimed to preferentially block the acetoclastic pathway. The cumulative CH4 production of all depths was almost one fold higher in hollows than in hummocks, with no differences in CO2. With depth, CO2 and CH4 production decreased, and the relative contribution of the hydrogenotrophic pathway of methanogenesis increased. The highest methanogenic activity among all depths and both microforms was measured at 15cm of hollows (91%) at which the highest relative contribution of acetoclastic vs. hydrogenotrophic pathway (92 and 8%, respectively) was detected. For hummocks, the CH4 production was the highest at 50cm (82%), where relative contribution of acetoclastic methanogenesis comprised 89%. The addition of 1mM BES was not selective and inhibited both methanogenic pathways in the soil. Thus, BES was less efficient in partitioning the pathways compared with the δ13C signature. We conclude that the peat microforms - dry hummocks and wet hollows - play an important role for CH4 but not for CO2 production when the effects of living vegetation are excluded.
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Affiliation(s)
- Johannes Krohn
- Department of Soil Science of Temperate Ecosystems, Faculty of Forest Sciences and Forest Ecology, Georg-August University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Ivana Lozanovska
- Department of Soil Science of Temperate Ecosystems, Faculty of Forest Sciences and Forest Ecology, Georg-August University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Yakov Kuzyakov
- Department of Soil Science of Temperate Ecosystems, Faculty of Forest Sciences and Forest Ecology, Georg-August University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany; Department of Agricultural Soil Science, Georg-August University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Shahnaj Parvin
- Department of Soil Science of Temperate Ecosystems, Faculty of Forest Sciences and Forest Ecology, Georg-August University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
| | - Maxim Dorodnikov
- Department of Soil Science of Temperate Ecosystems, Faculty of Forest Sciences and Forest Ecology, Georg-August University Göttingen, Büsgenweg 2, 37077 Göttingen, Germany.
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Meng Y, Jost C, Mumme J, Wang K, Linke B. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system. J Environ Sci (China) 2016; 45:200-206. [PMID: 27372134 DOI: 10.1016/j.jes.2016.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/18/2016] [Accepted: 01/21/2016] [Indexed: 06/06/2023]
Abstract
In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.
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Affiliation(s)
- Yao Meng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Department Bioengineering, Leibniz Institute for Agricultural Engineering, Max-Eyth-Allee 100, 14469 Potsdam, Germany.
| | - Carsten Jost
- Department Bioengineering, Leibniz Institute for Agricultural Engineering, Max-Eyth-Allee 100, 14469 Potsdam, Germany
| | - Jan Mumme
- UK Biochar Centre, School of GeoSciences, University of Edinburgh, Crew Building, King's Buildings, Edinburgh EH9 3JN, UK
| | - Kaijun Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
| | - Bernd Linke
- Department Bioengineering, Leibniz Institute for Agricultural Engineering, Max-Eyth-Allee 100, 14469 Potsdam, Germany
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Krayzelova L, Bartacek J, Kolesarova N, Jenicek P. Microaeration for hydrogen sulfide removal in UASB reactor. BIORESOURCE TECHNOLOGY 2014; 172:297-302. [PMID: 25270045 DOI: 10.1016/j.biortech.2014.09.056] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/10/2014] [Accepted: 09/13/2014] [Indexed: 06/03/2023]
Abstract
The removal of hydrogen sulfide from biogas by microaeration was studied in Up-flow Anaerobic Sludge Blanket (UASB) reactors treating synthetic brewery wastewater. A fully anaerobic UASB reactor served as a control while air was dosed into a microaerobic UASB reactor (UMSB). After a year of operation, sulfur balance was described in both reactors. In UASB, sulfur was mainly presented in the effluent as sulfide (49%) and in biogas as hydrogen sulfide (34%). In UMSB, 74% of sulfur was detected in the effluent (41% being sulfide and 33% being elemental sulfur), 10% accumulated in headspace as elemental sulfur and 9% escaped in biogas as hydrogen sulfide. The efficiency of hydrogen sulfide removal in UMSB was on average 73%. Microaeration did not cause any decrease in COD removal or methanogenic activity in UMSB and the elemental sulfur produced by microaeration did not accumulate in granular sludge.
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Affiliation(s)
- Lucie Krayzelova
- Department of Water Technology and Environmental Engineering, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic.
| | - Jan Bartacek
- Department of Water Technology and Environmental Engineering, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
| | - Nina Kolesarova
- Department of Chemical and Environmental Engineering, Slovak University of Technology in Bratislava, Radlinskeho 9, 812 37 Bratislava, Slovakia
| | - Pavel Jenicek
- Department of Water Technology and Environmental Engineering, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6, Czech Republic
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da Cruz GF, de Vasconcellos SP, Angolini CFF, Dellagnezze BM, Garcia INS, de Oliveira VM, dos Santos Neto EV, Marsaioli AJ. Could petroleum biodegradation be a joint achievement of aerobic and anaerobic microrganisms in deep sea reservoirs? AMB Express 2011; 1:47. [PMID: 22196374 PMCID: PMC3279308 DOI: 10.1186/2191-0855-1-47] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 12/23/2011] [Indexed: 11/10/2022] Open
Abstract
Several studies suggest that petroleum biodegradation can be achieved by either aerobic or anaerobic microorganisms, depending on oxygen input or other electron acceptors and appropriate nutrients. Evidence from in vitro experiments with samples of petroleum formation water and oils from Pampo Field indicate that petroleum biodegradation is more likely to be a joint achievement of both aerobic and anaerobic bacterial consortium, refining our previous observations of aerobic degradation. The aerobic consortium depleted, in decreasing order, hydrocarbons > hopanes > steranes > tricyclic terpanes while the anaerobic consortium depleted hydrocarbons > steranes > hopanes > tricyclic terpanes. The oxygen content of the mixed consortia was measured from time to time revealing alternating periods of microaerobicity (O2 ~0.8 mg.L-1) and of aerobicity (O2~6.0 mg.L-1). In this experiment, the petroleum biodegradation changed from time to time, alternating periods of biodegradation similar to the aerobic process and periods of biodegradation similar to the anaerobic process. The consortia showed preferences for metabolizing hydrocarbons > hopanes > steranes > tricyclic terpanes during a 90-day period, after which this trend changed and steranes were more biodegraded than hopanes. The analysis of aerobic oil degrading microbiota by the 16S rRNA gene clone library detected the presence of Bacillus, Brevibacterium, Mesorhizobium and Achromobacter, and the analysis of the anaerobic oil degrading microbiota using the same technique detected the presence of Bacillus and Acinetobacter (facultative strains). In the mixed consortia Stenotrophomonas, Brevibacterium, Bacillus, Rhizobium, Achromobacter and 5% uncultured bacteria were detected. This is certainly a new contribution to the study of reservoir biodegradation processes, combining two of the more important accepted hypotheses.
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Shin C, Lee E, McCarty PL, Bae J. Effects of influent DO/COD ratio on the performance of an anaerobic fluidized bed reactor fed low-strength synthetic wastewater. BIORESOURCE TECHNOLOGY 2011; 102:9860-9865. [PMID: 21906938 DOI: 10.1016/j.biortech.2011.07.109] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/27/2011] [Accepted: 07/29/2011] [Indexed: 05/31/2023]
Abstract
The effect of influent DO/COD (dissolved oxygen/chemical oxygen demand) ratio on the performance of an anaerobic fluidized bed reactor (AFBR) containing GAC was studied. A high influent DO concentration was found to have adverse impacts on organic removal efficiency, methane production, and effluent suspended solids (SS) concentration. These problems resulted with a DO/COD ratio of 0.12, but not at a lower ratio of 0.05. At first organic removal appeared satisfactory at the higher DO/COD ratio at a hydraulic retention time of 0.30 h, but soon a rapid growth of oxygen-consuming zoogloeal-like organisms resulted, eventually causing high effluent SS concentrations. The influent DO also had an inhibitory effect, resulting in a long recovery time for adequate methanogenic activity to return after influent DO removal began. With the growing interest in anaerobic treatment of low COD wastewaters, the increased possibility of similar adverse DO effects occurring needs consideration.
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Affiliation(s)
- Chungheon Shin
- Department of Environmental Engineering, Inha University, Namgu, Yonghyun dong 253, Incheon, Republic of Korea
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14
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Schneider I, Topalova Y. Effect of bioaugmentation on anaerobic wastewater treatment in the dairy industry. J Dairy Sci 2011; 94:4389-97. [DOI: 10.3168/jds.2009-2670] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 05/03/2011] [Indexed: 11/19/2022]
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15
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Chen YC, Lin CJ, Chen HL, Fu SY, Zhan HY. Cultivation of Biogranules in a Continuous Flow Reactor at Low Dissolved Oxygen. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11267-009-9216-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Venkata Mohan S, Purushotham Reddy B, Sarma PN. Ex situ slurry phase bioremediation of chrysene contaminated soil with the function of metabolic function: process evaluation by data enveloping analysis (DEA) and Taguchi design of experimental methodology (DOE). BIORESOURCE TECHNOLOGY 2009; 100:164-172. [PMID: 18657417 DOI: 10.1016/j.biortech.2008.06.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Revised: 06/03/2008] [Accepted: 06/04/2008] [Indexed: 05/26/2023]
Abstract
Bioremediation of chrysene in soil matrix was evaluated in soil slurry phase bioreactor in conjugation with metabolic functions (aerobic, anoxic and anaerobic), microenvironment (single and mixed) conditions and nature of mixed consortia (native/resident mixed microflora and bioaugmented inoculum). Twelve experiments were operated independently in agitated-batch reactor keeping all other operating conditions constant (substrate loading rate--0.084 g chrysene/kg soil-day; soil loading rate--10 kg soil/m(3)-day (3:25 soil water ratio); operating temperature--35+/-2 degrees C). Data envelopment analysis (DEA) procedure was employed to analyze the performance of experimental variations in terms of chrysene degradation and pH. The efficacy of anoxic metabolism over the corresponding aerobic and anaerobic metabolic functions was documented. Aerobic metabolic function showed effective degradation capability under mixed microenvironment after augmentation with anaerobic inoculum. Anaerobic metabolic function showed lowest degradation potential. Application of bioaugmentation showed positive influence on the chrysene degradation rate. Design of experimental methodology (DOE) by Taguchi approach was applied to evaluate the effect of four selected factors (native soil microflora, microenvironment, metabolic function and bioaugmentation) on the chrysene degradation process. The optimized factors derived from analysis depicted the requirement of native soil microflora under anoxic metabolic function using mixed microenvironment after augmenting with anaerobic inoculum for achieving effective chrysene degradation efficacy.
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Affiliation(s)
- S Venkata Mohan
- Bioengineering and Environmental Centre, Indian Institute of Chemical Technology, Hyderabad, India.
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17
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Zhu GF, Li JZ, Wu P, Jin HZ, Wang Z. The performance and phase separated characteristics of an anaerobic baffled reactor treating soybean protein processing wastewater. BIORESOURCE TECHNOLOGY 2008; 99:8027-8033. [PMID: 18450441 DOI: 10.1016/j.biortech.2008.03.046] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 03/19/2008] [Accepted: 03/20/2008] [Indexed: 05/26/2023]
Abstract
A laboratory-scale anaerobic baffled reactor (ABR) with four compartments using soybean protein processing wastewater as organic loading rates (OLRs) was investigated for the performance and phase separated characteristics. It was found that the chemical oxygen demand (COD) removal efficiencies were 92-97% at 1.2-6.0kgCOD/m3d feeding. The dominated species, propionate and butyrate, were found in the 1st compartment. Acetate was dominated in the 2nd compartment and then decreased in the 3rd and 4th. Meanwhile, 93% volatile fatty acids (VFAs) were removed in the 3rd and 4th compartments. In the 1st compartment, biogas revealed carbon dioxide (CO2) and hydrogen (H2). The highest H2 yield was found in the 2nd compartment, thereafter decreased from the 2nd to 4th which corresponded to the increased of the methane (CH4) yield. It indicated that the proper anaerobic consortium in each separate compartment was developed along with substrate availability and specific environmental conditions.
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Affiliation(s)
- Ge-Fu Zhu
- Institute of Urban Environment, Chinese Academy of Sciences, No. 2 Huyuan Road, Xiamen 361003, China.
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18
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Guiot SR, Cimpoia R, Kuhn R, Alaplantive A. Electrolytic methanogenic-methanotrophic coupling for tetrachloroethylene bioremediation: proof of concept. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:3011-3017. [PMID: 18497159 DOI: 10.1021/es702121u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Coupling of methanogenic and methanotrophic catabolisms was performed in a single-stage technology equipped with a water electrolysis cell placed in the effluent recirculation loop. The electrolysis-generated hydrogen served as an electron donor for both bicarbonate reduction into CH4 and reductive dechlorination, while the O2 and CH4, supported the cometabolic oxidation of chlorinated intermediates left over by the tetrachloroethylene (PCE) transformation. The electrolytical methanogenic/methanotrophic coupled (eMaMoC) process was tested in a laboratory-scale setup at PCE loads ranging from 5 to 50 micromol/L(rx) x d (inlet concentrations from 4 to 11 mg/L), and at various hydraulic residence times (HRT). Degradation followed essentially a reductive dechlorination pathway from PCE to cis-1,2-dichloroethene (DCE), and an oxidative pathway from DCE to CO2. PCE reductive dechlorination to DCE was consistently over 98% while a maximum oxidative DCE mineralization of 89% was obtained at a load of 4.3 micromol PCE/ L(rx) x d and an HRT of 6 days. Controlling dissolved oxygen concentrations within a relatively low range (2-3 mg/L) seemed instrumental to sustain the overall degradation capacity. Degradation kinetics were further evaluated: the apparent half-saturation constant (K(s)) had to be set relatively high (29 microM) for the simulated data to best fit the experimental ones. In spite of such kinetic limitations, the eMaMoC system, while fueled by water electrolysis, was effective in building and sustaining a functional methanogenic/methanotrophic consortium capable of significant PCE mineralization in a single-stage process. Hence, degradation standards are within reach so long as the methanotrophic DCE-oxidizing potential, including substrate affinity, are optimized and HRT accordingly adjusted.
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Affiliation(s)
- Serge R Guiot
- National Research Council, Biotechnology Research Institute, 6100 Royalmount Avenue, Montreal, QC H4P 2R2, Canada.
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19
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Baloch MI, Akunna JC, Kierans M, Collier PJ. Structural analysis of anaerobic granules in a phase separated reactor by electron microscopy. BIORESOURCE TECHNOLOGY 2008; 99:922-9. [PMID: 17531476 DOI: 10.1016/j.biortech.2007.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 03/11/2007] [Accepted: 03/11/2007] [Indexed: 05/15/2023]
Abstract
This paper discusses the microbial community structure of anaerobic granules and the effect of phase separation in anaerobic reactor on the characteristics of granules. Electron micrographs revealed that the core of anaerobic granular sludge consists predominantly of Methanosaeta-like cells, a key microorganism in granulation process. Granules in the methanogenic dominant zone of the reactor were stable and densely packed with smooth regular surface. On the other hand, granules subjected to acidogenic activities were less stable structures with broken parts and an irregular fissured surface. Anaerobic granules consisted of a vast diversity of species from the outer surface to the core of the granule and possessed a multi-layered structure. Viruses in the granules suggests the presence of bacteriophage in the granular biomass. These could be responsible for destroying cells and weakening the internal structure of granules, and thus possibly causing the breaking of granules. The observation of protozoa-like microorganism on the exterior zone of granular structure is believed to play an important role as bacterial predator and control the growth of bacterial cells. The images observed in this study shows that anaerobic granule harbour diverse number of microbial species, and act differently in acidogenic and methanogenic microbial zones.
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Affiliation(s)
- M I Baloch
- Wessex Water, Bristol Wastewater Treatment Works, Kings Weston Lane, Avonmouth, Bristol BS11 0YS, UK.
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20
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Garibay-Orijel C, Hoyo-Vadillo C, Ponce-Noyola T, García-Mena J, Poggi-Varaldo HM. Impact of long-term partial aeration on the removal of 2,4,6-trichlorophenol in an initially methanogenic fluidized bed bioreactor. Biotechnol Bioeng 2006; 94:949-60. [PMID: 16586508 DOI: 10.1002/bit.20918] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A fluidized bed bioreactor (FBBR) was operated for more than 1000 days under two regimes, Methanogenic (M) and Methanogenic-Aerobic (M-A), to remove 2,4,6-trichlorophenol (TCP) and phenol (Phe) from a synthetic wastewater, containing different amounts of TCP and Phe, using different aeration flow-rates (0, 2.13, and 1.06 NL O(2)/L.day). M conditions (80:20 mg/L of TCP:Phe, 0 NL O(2)/L.day) showed similar TCP and Phe removal (>95%). Nevertheless accumulation of 4-chlorophenol (4CP) up to 16 mg/L and Phe up to 4 mg/L was observed, while in M-A conditions (80:20 mg/L of TCP:Phe, 2.13 NL O(2)/L.day) TCP and Phe removal achieved 99.9(+)% and after 70 days no accumulation of intermediates were detected. The increase of TCP and Phe in the influent under M-A conditions from 80:20 to 120:30 mg/L of TCP:Phe did not negatively affect the removal of TCP, intermediates and Phe; in fact, they were similar to those in previous M-A conditions. The decrease in the oxygen flow rate from 2.13 to 1.06 NL O(2)/L.day had no negative effect on pollutant removals, which were as high as in previous two M-A conditions. The specific methanogenic activity of bioparticles of the fluidized bed decreased with long-term partial aeration, starting from 1.097 mmol CH(4)/h.g(TKN) in the M regime (day 60) to <0.02 mmolCH(4)/h.g(TKN) at day 1050, suggesting aerobic regime in the bioreactor rather than an M-A regime. In conclusion, complete removal of TCP and less chlorinated intermediates could be achieved in an initially methanogenic FBBR under conditions of partial aeration, although long-term operation seemed to negatively affect the methanogenic activity of biomass. It is also likely that after extended aeration the microbial community was finally enriched with strains with the ability to attack 2,4,6-TCP under aerobic conditions. This report represents the first evidence of a long exposure to oxygen of an anaerobic microbial consortium that efficiently remove TCP.
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21
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Baloch MI, Akunna JC, Collier PJ. Assessment of morphology for anaerobic-granular particles. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2006; 78:643-6. [PMID: 16894989 DOI: 10.2175/106143005x90056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
This study shows that a proper assessment of granule morphology is fundamental before applying any mathematical derivation or empirical formula based on the shape factor of anaerobic-granular particles to determine granular characteristics. The granular images and size distribution of samples observed in this study revealed two different dimensions along two axes, which characterize these particles as ellipsoids. In the literature, theoretical-settling velocities and particle-size distribution of anaerobic granules have been calculated by assuming granules as spherical-shaped and using the numerical correlation between the size and settling velocity. This resulted in large deviations in results reported for settling velocities and size distribution calculated by using empirical equations when compared with experimentally measured values. It is believed that, because of the nonspherical nature of these particles, errors have been made in the earlier studies (which considered these particles as spherical), while evaluating granular-physical properties.
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Affiliation(s)
- M I Baloch
- Wessex Water, Wessex Engineering Services, Claverton Down, Bath, United Kingdom.
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22
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Chipasa KB, Medrzycka K. Behavior of lipids in biological wastewater treatment processes. J Ind Microbiol Biotechnol 2006; 33:635-45. [PMID: 16491352 DOI: 10.1007/s10295-006-0099-y] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Accepted: 02/03/2006] [Indexed: 11/28/2022]
Abstract
Lipids (characterized as oils, greases, fats and long-chain fatty acids) are important organic components of wastewater. Their amount, for example, in municipal wastewater is approximately 30-40% of the total chemical oxygen demand. The concern over the behavior of lipids in biological treatment systems has led to many studies, which have evaluated their removal, but still the exact behavior of lipids in these processes is not well understood. In this review, we discuss the current knowledge of how lipids/fatty acids affect both aerobic and anaerobic processes and specific methods that have been used in an attempt to enhance their removal from wastewater. Overall, the literature shows that lipids/fatty acids are readily removed by biological treatment methods, inhibitory to microbial growth as well as the cause of foaming, growth of filamentous bacteria and floc flotation.
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Affiliation(s)
- K B Chipasa
- Chemical Faculty, Gdansk University of Technology, Narutowicza 11/12, 80-952, Gdansk, Poland.
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23
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Shaw CB, Carliell CM, Wheatley AD. Anaerobic/aerobic treatment of coloured textile effluents using sequencing batch reactors. WATER RESEARCH 2002; 36:1993-2001. [PMID: 12092574 DOI: 10.1016/s0043-1354(01)00392-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Conventional biological wastewater treatment plants do not easily degrade the dyes and polyvinyl alcohols (PVOH) in textile effluents. Results are reported on the possible advantages of anaerobic/aerobic cometabolism in sequenced redox reactors. A six phase anaerobic/aerobic sequencing laboratory scale batch reactor was developed to treat a synthetic textile effluent. The wastewater included PVOH from desizing and an azo dye (Remazol Black). The reactor removed 66% of the applied total organic carbon (load F: M 0.15) compared to 76% from a control reactor without dye. Colour removal was 94% but dye metabolites caused reactor instability. Aromatic amines from the anaerobic breakdown of the azo dyes were not completely mineralised by the aerobic phase. Breakdown of PVOH by the reactor (20-30%) was not as good as previous reports with entirely aerobic cultures. The anaerobic cultures were able to tolerate the oxygen and methane continued to be produced but there was a deterioration in settlement.
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Affiliation(s)
- C B Shaw
- Department of Civil & Building Engineering, Loughborough University, UK
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24
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Tartakovsky B, Levesque M, Dumortier R, Beaudet R, Guiot SR. Biodegradation of pentachlorophenol in a continuous anaerobic reactor augmented with Desulfitobacterium frappieri PCP-1. Appl Environ Microbiol 1999; 65:4357-62. [PMID: 10508060 PMCID: PMC91578 DOI: 10.1128/aem.65.10.4357-4362.1999] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this work, a strain of anaerobic pentachlorophenol (PCP) degrader, Desulfitobacterium frappieri PCP-1, was used to augment a mixed bacterial community of an anaerobic upflow sludge bed reactor degrading PCP. To estimate the efficiency of augmentation, the population of PCP-1 in the reactor was enumerated by a competitive PCR technique. The PCP-1 strain appeared to compete well with other microorganisms of the mixed bacterial community, with its population increasing from 10(6) to 10(10) cells/g of volatile suspended solids within a period of 70 days. Proliferation of strain PCP-1 allowed for a substantial increase of the volumetric PCP load from 5 to 80 mg/liter of reaction volume/day. A PCP removal efficiency of 99% and a dechlorination efficiency of not less than 90.5% were observed throughout the experiment, with 3-Cl-phenol and phenol being observable dechlorination intermediates.
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Affiliation(s)
- B Tartakovsky
- Biotechnology Research Institute, NRC, Montreal, Quebec, Canada H4P 2A2
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25
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Miguez CB, Shen CF, Bourque D, Guiot SR, Groleau D. Monitoring methanotrophic bacteria in hybrid anaerobic-aerobic reactors with PCR and a catabolic gene probe. Appl Environ Microbiol 1999; 65:381-8. [PMID: 9925557 PMCID: PMC91036 DOI: 10.1128/aem.65.2.381-388.1999] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/1998] [Accepted: 11/04/1998] [Indexed: 11/20/2022] Open
Abstract
We attempted to mimic in small upflow anaerobic sludge bed (UASB) bioreactors the metabolic association found in nature between methanogens and methanotrophs. UASB bioreactors were inoculated with pure cultures of methanotrophs, and the bioreactors were operated by using continuous low-level oxygenation in order to favor growth and/or survival of methanotrophs. Unlike the reactors in other similar studies, the hybrid anaerobic-aerobic bioreactors which we used were operated synchronously, not sequentially. Here, emphasis was placed on monitoring various methanotrophic populations by using classical methods and also a PCR amplification assay based on the mmoX gene fragment of the soluble methane monooxygenase (sMMO). The following results were obtained: (i) under the conditions used, Methylosinus sporium appeared to survive better than Methylosinus trichosporium; (ii) the PCR method which we used could detect as few as about 2,000 sMMO gene-containing methanotrophs per g (wet weight) of granular sludge; (iii) inoculation of the bioreactors with pure cultures of methanotrophs contributed greatly to increases in the sMMO-containing population (although the sMMO-containing population decreased gradually with time, at the end of an experiment it was always at least 2 logs larger than the initial population before inoculation); (iv) in general, there was a good correlation between populations with the sMMO gene and populations that exhibited sMMO activity; and (v) inoculation with sMMO-positive cultures helped increase significantly the proportion of sMMO-positive methanotrophs in reactors, even after several weeks of operation under various regimes. At some point, anaerobic-aerobic bioreactors like those described here might be used for biodegradation of various chlorinated pollutants.
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Affiliation(s)
- C B Miguez
- Microbial and Enzymatic Technology Group, Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada H4P 2R2
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