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Ranzinger F, Horn H, Wagner M. Imaging of particle deposition and resulting flow field during flocculation filtration within a granulated activated carbon filter. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.121033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Yuan J, Passeport E, Hofmann R. Understanding adsorption and biodegradation in granular activated carbon for drinking water treatment: A critical review. WATER RESEARCH 2022; 210:118026. [PMID: 34996013 DOI: 10.1016/j.watres.2021.118026] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Drinking water treatment plants use granular activated carbon (GAC) to adsorb and remove trace organics, but the GAC has a limited lifetime in terms of adsorptive capacity and needs to be replaced before it is exhausted. Biological degradation of target contaminants can also occur in GAC filters, which might allow the GAC to remain in service longer than expected. However, GAC biofiltration remains poorly understood and unpredictable. To increase the understanding of adsorption and biodegradation in GAC, previous studies have conducted parallel column tests that use one column of GAC (potentially biologically active) to assess overall removal via both adsorption and biodegradation, and one column with either sterilized GAC or biological non-adsorbing media to assess adsorption or biodegradation alone. Mathematical models have also been established to give insight into the adsorption and biodegradation processes in GAC. In this review, the experimental and modeling approaches and results used to distinguish between the role of adsorption and biodegradation were summarized and critically discussed. We identified several limitations: (1) using biological non-adsorbing media in column tests might lead to non-representative extents of biodegradation; (2) sterilization methods may not effectively inhibit biological activity and may affect adsorption; (3) using virgin GAC coated with biofilm could overestimate adsorption; (4) potential biofilm detachment during column experiments could lead to biased results; (5) the parallel column test approach itself is not universally applicable; (6) competitive adsorption was neglected by previous models; (7) model formulations were based on virgin GAC only. To overcome these limitations, we proposed four new approaches: the use of gamma irradiation for sterilization, a novel minicolumn test, compound-specific isotope analysis to decipher the role of adsorption and biodegradation in situ, and a new model to simulate trace organic adsorption and biodegradation in a GAC filter .
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Affiliation(s)
- Jie Yuan
- Department of Civil & Mineral Engineering, University of Toronto, 35St George Street, Toronto, ON, M5S 1A4 Canada.
| | - Elodie Passeport
- Department of Civil & Mineral Engineering, University of Toronto, 35St George Street, Toronto, ON, M5S 1A4 Canada; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5 Canada
| | - Ron Hofmann
- Department of Civil & Mineral Engineering, University of Toronto, 35St George Street, Toronto, ON, M5S 1A4 Canada
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Kinetics and Performance of Biological Activated Carbon Reactor for Advanced Treatment of Textile Dye Wastewater. Processes (Basel) 2022. [DOI: 10.3390/pr10010129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The kinetics and performance of a biological activated carbon (BAC) reactor were evaluated to validate the proposed kinetic model. The Freundlich adsorption capacity (Ka) and adsorption intensity constants (n) obtained from the batch experiments were 1.023 ± 0.134 (mg/g) (L/mg)1/n and 2.036 ± 0.785, respectively. The effective diffusivity (Ds) of the substrate within the activated carbon was determined by comparing the adsorption model value with the experimental data to find the best fit value (4.3 × 10–4 cm2/d). The batch tests revealed that the yield coefficient (Y) was 0.18 mg VSS/mg COD. Monod and Haldane kinetics were applied to fit the experimental data and determine the biokinetic constants, such as the maximum specific utilization rate (k), half-saturation constant (KS), inhibition constant (Ki), and biomass death rate coefficient (kd). The results revealed that the Haldane kinetics fit the experimental data better than the Monod kinetics. The values of k, KS, Ki, and kd were 3.52 mg COD/mg VSS-d, 71.7 mg COD/L, 81.63 mg COD/L, and 4.9 × 10−3 1/d, respectively. The BAC reactor had a high COD removal efficiency of 94.45% at a steady state. The average influent color was found to be 62 ± 22 ADMI color units, and the color removal efficiency was 73–100% (average 92.3 ± 10.2%). The removal efficiency for ammonium was 73.9 ± 24.4%, while the residual concentration of ammonium in the effluent was 1.91 ± 2.04 mg/L. The effluent quality from the BAC reactor could meet the discharge standard and satisfy the reuse requirements of textile dye wastewater.
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Hess A, Morgenroth E. Biological activated carbon filter for greywater post-treatment: Long-term TOC removal with adsorption and biodegradation. WATER RESEARCH X 2021; 13:100113. [PMID: 34611621 PMCID: PMC8476437 DOI: 10.1016/j.wroa.2021.100113] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/19/2021] [Accepted: 08/09/2021] [Indexed: 05/30/2023]
Abstract
Biological activated carbon (BAC) filters can be used to remove residual total organic carbon (TOC) from greywater after a membrane bioreactor. The two main TOC removal processes are adsorption to the granular activated carbon (GAC) and biological degradation. Biodegradation leads to the growth of microorganisms in the filter bed, which can lead to increased pressure loss over the filter bed. However, the roles of sorption and biodegradation in long-term TOC removal and how they complement each other are unclear. We monitored TOC removal from greywater in a BAC filter installed following a membrane bioreactor over more than 900 days. Removal performance depended on the operational time of the BAC filter, the influent TOC concentration, and in the upper part of the filter on the empty bed contact time (EBCT). Across the overall filter, the EBCT did not significantly influence TOC removal, showing that the filter was sufficiently large for the range of flow rates observed. Analysis of the long-term data revealed the equal importance of sorption and biodegradation over the whole operation period and the whole filter bed. Most of the TOC was removed in the upper part of the filter, where biodegradation was the dominant mechanism. In the lower part of the filter, sorption capacity remained and allowed high influent TOC concentrations to be buffered. The generous filter design with low average filtration rates ensured long-term TOC removal. The only maintenance needed was backwashing, which was required only after more than 800 days of operation. Backwashing effectively reduced the pressure loss but had no significant influence on the effluent water quality. Our study shows that BAC filters are a suitable post-treatment step for the treatment of greywater with highly variable flow and TOC concentrations.
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Affiliation(s)
- Angelika Hess
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Eberhard Morgenroth
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
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Zhiteneva V, Ziemendorf É, Sperlich A, Drewes JE, Hübner U. Differentiating between adsorption and biodegradation mechanisms while removing trace organic chemicals (TOrCs) in biological activated carbon (BAC) filters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140567. [PMID: 32659552 DOI: 10.1016/j.scitotenv.2020.140567] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/20/2020] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
Efficient adsorption of certain trace organic chemicals (TOrCs) present in secondary treated municipal wastewater treatment plant (WWTP) effluents onto granular activated carbon (GAC) has already been demonstrated at lab- and full-scale. Due to high organic matter concentrations in WWTP effluents, GAC filters eventually develop a biofilm and turn into biological activated carbon filters (BAC), where removal of organic compounds is governed by biodegradation as well as by adsorption. However, determining TOrC breakthrough by conducting a long-term BAC column experiment to discern between the removal mechanisms is not possible due to competition for adsorption sites, fluctuating water quality, and other variables. Therefore, a rapid small scale column test (RSSCT) was conducted to determine the contribution of adsorption for select chemicals at 10,000 bed volumes treated (BVT). These results were then used in the pore surface diffusion model (PSDM) to model adsorption behavior at 40,000 BVTs. Pseudo-Freundlich K values obtained from the PSDM model were compared with K values obtained from an integral mass balance calculation. This comparison revealed that the modeling was most accurate for moderately to poorly adsorptive compounds. In comparing RSSCT results to long-term BAC columns, the modeling approach best predicted BAC removal of well adsorbing compounds, such as atenolol, trimethoprim, metoprolol, citalopram, and benzotriazole. However, differences in predicted vs observed BAC removal for the removals of venlafaxine, tramadol and carbamazepine revealed that BAC adsorption capacity was not yet exhausted for these compounds. Therefore, a comparison was not possible. The approach would be improved by operation at longer EBCT and improved calculation of compound fouling indices.
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Affiliation(s)
- Veronika Zhiteneva
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany.
| | - Éric Ziemendorf
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany.
| | - Alexander Sperlich
- Berliner Wasserbetriebe, Research and Development, 10864 Berlin, Germany.
| | - Jörg E Drewes
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany.
| | - Uwe Hübner
- Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany.
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6
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Nigri EM, Cechinel MAP, Mayer DA, Mazur LP, Loureiro JM, Rocha SDF, Vilar VJP. Cow bones char as a green sorbent for fluorides removal from aqueous solutions: batch and fixed-bed studies. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:2364-2380. [PMID: 27815851 DOI: 10.1007/s11356-016-7816-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/03/2016] [Indexed: 06/06/2023]
Abstract
Cow bone char was investigated as sorbent for the defluoridation of aqueous solutions. The cow bone char was characterized in terms of its morphology, chemical composition, and functional groups present on the bone char surface using different analytical techniques: SEM, EDS, N2-BET method, and FTIR. Batch equilibrium studies were performed for the bone chars prepared using different procedures. The highest sorption capacities for fluoride were obtained for the acid washed (q = 6.2 ± 0.5 mg/g) and Al-doped (q = 6.4 ± 0.3 mg/g) bone chars. Langmuir and Freundlich models fitted well the equilibrium sorption data. Fluoride removal rate in batch system is fast in the first 5 h, decreasing after this time until achieving equilibrium due to pore diffusion. The presence of carbonate and bicarbonate ions in the aqueous solution contributes to a decrease of the fluoride sorption capacity of the bone char by 79 and 31 %, respectively. Regeneration of the F-loaded bone char using 0.5 M NaOH solution leads to a sorption capacity for fluoride of 3.1 mg/g in the second loading cycle. Fluoride breakthrough curve obtained in a fixed-bed column presents an asymmetrical S-shaped form, with a slow approach of C/C 0 → 1.0 due to pore diffusion phenomena. Considering the guideline value for drinking water of 1.5 mg F-/L, as recommended by World Health Organization, the service cycle for fluoride removal was of 71.0 h ([F-]feed ∼ 9 mg/L; flow rate = 1 mL/min; m sorbent = 12.6 g). A mass transfer model considering the pore diffusion was able to satisfactorily describe the experimental data obtained in batch and continuous systems.
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Affiliation(s)
- Elbert M Nigri
- Mining Engineering Department, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 7727, Pampulha, Belo Horizonte, Brazil
| | - Maria Alice P Cechinel
- Laboratório de Transferência de Massa e Simulação Numérica de Sistemas Químicos, Federal University of Santa Catarina, PO Box 476, Florianópolis, SC, CEP 88040-900, Brazil
| | - Diego A Mayer
- Laboratório de Transferência de Massa e Simulação Numérica de Sistemas Químicos, Federal University of Santa Catarina, PO Box 476, Florianópolis, SC, CEP 88040-900, Brazil
| | - Luciana P Mazur
- Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - José M Loureiro
- Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal
| | - Sônia D F Rocha
- Mining Engineering Department, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 7727, Pampulha, Belo Horizonte, Brazil.
| | - Vítor J P Vilar
- Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Chemical Engineering Department, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal.
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Li H, Fu Z, Yan C, Huang J, Liu YN, Kirin SI. Hydrophobic–hydrophilic post-cross-linked polystyrene/poly (methyl acryloyl diethylenetriamine) interpenetrating polymer networks and its adsorption properties. J Colloid Interface Sci 2016; 463:61-8. [DOI: 10.1016/j.jcis.2015.10.044] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/08/2015] [Accepted: 10/17/2015] [Indexed: 10/22/2022]
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Islam MS, Zhang Y, McPhedran KN, Liu Y, Gamal El-Din M. Mechanistic investigation of industrial wastewater naphthenic acids removal using granular activated carbon (GAC) biofilm based processes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 541:238-246. [PMID: 26410699 DOI: 10.1016/j.scitotenv.2015.09.091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/16/2015] [Accepted: 09/17/2015] [Indexed: 06/05/2023]
Abstract
Naphthenic acids (NAs) found in oil sands process-affected waters (OSPW) have known environmental toxicity and are resistant to conventional wastewater treatments. The granular activated carbon (GAC) biofilm treatment process has been shown to effectively treat OSPW NAs via combined adsorption/biodegradation processes despite the lack of research investigating their individual contributions. Presently, the NAs removals due to the individual processes of adsorption and biodegradation in OSPW bioreactors were determined using sodium azide to inhibit biodegradation. For raw OSPW, after 28 days biodegradation and adsorption contributed 14% and 63% of NA removal, respectively. For ozonated OSPW, biodegradation removed 18% of NAs while adsorption reduced NAs by 73%. Microbial community 454-pyrosequencing of bioreactor matrices indicated the importance of biodegradation given the diverse carbon degrading families including Acidobacteriaceae, Ectothiorhodospiraceae, and Comamonadaceae. Overall, results highlight the ability to determine specific processes of NAs removals in the combined treatment process in the presence of diverse bacteria metabolic groups found in GAC bioreactors.
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Affiliation(s)
- Md Shahinoor Islam
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 2W2, Canada; Department of Chemical Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh
| | - Yanyan Zhang
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 2W2, Canada
| | - Kerry N McPhedran
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 2W2, Canada; Department of Civil and Geological Engineering, College of Engineering, University of Saskatchewan, Saskatoon S7N 5A9, Canada
| | - Yang Liu
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 2W2, Canada.
| | - Mohamed Gamal El-Din
- Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 2W2, Canada.
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The Removal of Hydrogen Sulfide from Biogas in a Microaerobic Biotrickling Filter Using Polypropylene Carrier as Packing Material. Appl Biochem Biotechnol 2015; 175:3763-77. [DOI: 10.1007/s12010-015-1545-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 02/09/2015] [Indexed: 10/24/2022]
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10
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Lee MC, Lin YH, Yu HW. Kinetics of nitrification in a fixed biofilm reactor using dewatered sludge-fly ash composite ceramic particle as a supporting medium. Biodegradation 2014; 25:849-65. [DOI: 10.1007/s10532-014-9705-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 08/05/2014] [Indexed: 11/30/2022]
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Wu W, Zhang L, Chen Y, Liu W, Tu Y, Zhou J. Interaction between activated carbon and microorganisms in PACT process. CAN J CHEM ENG 2014. [DOI: 10.1002/cjce.21983] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Wei Wu
- State Key Laboratory of Pollution Control and Resources Reuse; School of the Environment; Nanjing University; Nanjing 210046 China
- Jiangsu Provincial Academy of Environmental Science; Nanjing 210036 China
| | - Long Zhang
- Jiangsu Provincial Academy of Environmental Science; Nanjing 210036 China
| | - Yong Chen
- Jiangsu Provincial Academy of Environmental Science; Nanjing 210036 China
| | - Weijing Liu
- Jiangsu Provincial Academy of Environmental Science; Nanjing 210036 China
| | - Yong Tu
- Jiangsu Provincial Academy of Environmental Science; Nanjing 210036 China
| | - Jun Zhou
- Jiangsu Provincial Academy of Environmental Science; Nanjing 210036 China
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Oh WD, Lim PE, Seng CE, Sujari ANA. Kinetic modeling of bioregeneration of chlorophenol-loaded granular activated carbon in simultaneous adsorption and biodegradation processes. BIORESOURCE TECHNOLOGY 2012; 114:179-187. [PMID: 22503192 DOI: 10.1016/j.biortech.2012.03.065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/12/2012] [Accepted: 03/13/2012] [Indexed: 05/31/2023]
Abstract
A kinetic model incorporating adsorption, desorption and biodegradation processes was developed to describe the bioregeneration of granular activated carbon (GAC) loaded with 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP), respectively, in simultaneous adsorption and biodegradation processes. The model was numerically solved and the results showed that the kinetic model was well-fitted (R(2)>0.83) to the experimental data at different GAC dosages and at various initial 4-CP and 2,4-DCP concentrations. The rate of bioregeneration in simultaneous adsorption and biodegradation processes was influenced by the ratio of initial chlorophenol concentration to GAC dosage. Enhancement in the rate of bioregeneration was achieved by using the lowest ratio under either one of the following experimental conditions: (1) increasing initial chlorophenol concentration at constant GAC dosage and (2) increasing GAC dosage at constant initial chlorophenol concentration. It was found that the rate enhancement was more pronounced under the second experimental condition.
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Affiliation(s)
- Wen-Da Oh
- School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
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Nath K, Bhakhar MS. Microbial regeneration of spent activated carbon dispersed with organic contaminants: mechanism, efficiency, and kinetic models. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2011; 18:534-546. [PMID: 21152991 DOI: 10.1007/s11356-010-0426-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 11/25/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND AND PURPOSE Regeneration of spent activated carbon assumes paramount importance in view of its economic reuse during adsorptive removal of organic contaminants. Classical thermal, chemical, or electrochemical regeneration methods are constrained with several limitations. Microbial regeneration of spent activated carbon provides a synergic combination of adsorption and biodegradation. METHODS Microorganisms regenerate the surface of activated carbon using sorbed organic substrate as a source of food and energy. Aromatic hydrocarbons, particularly phenols, including their chlorinated derivatives and industrial waste water containing synthetic organic compounds and explosives-contaminated ground water are the major removal targets in adsorption-bioregeneration process. Popular mechanisms of bioregeneration include exoenzymatic hypothesis and biodegradation following desorption. Efficiency of bioregeneration can be quantified using direct determination of the substrate content on the adsorbent, the indirect measurement of substrate consumption by measuring the carbon dioxide production and the measurement of oxygen uptake. Modeling of bioregeneration involves the kinetics of adsorption/desorption and microbial growth followed by solute degradation. Some modeling aspects based on various simplifying assumptions for mass transport resistance, microbial kinetics and biofilm thickness, are briefly exposed. RESULTS Kinetic parameters from various representative bioregeneration models and their solution procedure are briefly summarized. The models would be useful in predicting the mass transfer driving forces, microbial growth, substrate degradation as well as the extent of bioregeneration. CONCLUSIONS Intraparticle mass transfer resistance, incomplete regeneration, and microbial fouling are some of the problems needed to be addressed adequately. A detailed techno-economic evaluation is also required to assess the commercial aspects of bioregeneration.
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Affiliation(s)
- Kaushik Nath
- Department of Chemical Engineering, G H Patel College of Engineering and Technology, Vallabh Vidyanagar, Gujarat 399120, India.
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Jiang X, Tay JH. Removal mechanisms of H(2)S using exhausted carbon in biofiltration. JOURNAL OF HAZARDOUS MATERIALS 2011; 185:1543-1549. [PMID: 21075518 DOI: 10.1016/j.jhazmat.2010.10.085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/14/2010] [Accepted: 10/20/2010] [Indexed: 05/30/2023]
Abstract
Exhausted carbon which comes from the H(2)S adsorption process may be a hazardous waste. In this study, exhausted carbon was re-used in biofiltration for H(2)S removal. Two identical columns were used for exhausted carbon (Column A) and fresh carbon (Column B). They were operated in the same mode with 35 ppmv of H(2)S gas at an empty bed residence time (EBRT) of 10s. The results show that the removal efficiency of H(2)S in the two columns was almost identical at 95-100%. The removal mechanisms of H(2)S was explored and explained by developing a mathematical model. The model incorporated mass transfer, biodegradation, adsorption, as well as biofilm growth. The developed model can predict the experimental results very well. The modeled results suggest that the removal of H(2)S in Column A was attributed to the adsorption mechanism much less than in Column B during the start-up stage, while the removal of H(2)S by the biodegradation in Column A was much higher. The removal of H(2)S by the adsorption was significantly affected by the biodegradation. The simulation results also suggest that column A achieved the steady-state biodegradation in a shorter time than in Column B. This could result from higher biomass concentration of biofilm in Column A, due to the extra sulfur source from pre-adsorbed sulfur on exhausted carbon besides H(2)S gas feeding.
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Affiliation(s)
- Xia Jiang
- School of Civil and Environmental Engineering, Nanyang Technological University, Blk N1, 50 Nanyang Avenue, Singapore 639798, Singapore.
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Mohamed M, Hatfield K. Dimensionless parameters to summarize the influence of microbial growth and inhibition on the bioremediation of groundwater contaminants. Biodegradation 2010; 22:877-96. [DOI: 10.1007/s10532-010-9445-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 12/10/2010] [Indexed: 10/18/2022]
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16
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Simpson DR. Biofilm processes in biologically active carbon water purification. WATER RESEARCH 2008; 42:2839-48. [PMID: 18405938 DOI: 10.1016/j.watres.2008.02.025] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Revised: 02/26/2008] [Accepted: 02/27/2008] [Indexed: 05/12/2023]
Abstract
This review paper serves to describe the composition and activity of a biologically active carbon (BAC) biofilm used in water purification. An analysis of several physical-chemical, biochemical and microbiological methods (indicators) used to characterize the BAC biofilm's composition and activity is provided. As well, the ability of the biofilm to remove and biodegrade waterborne organic substances and pollutants will be reviewed, with context to other industrial processes such as pre-ozonation and post-membrane filtration. Strategies to control the growth of the BAC biofilm, such as varying the nutrient loading rate, manipulating influent DO and pH levels, altering the frequency of BAC filter backwashing and applying oxidative disinfection, will be described in detail along with their respective process control challenges.
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Affiliation(s)
- David R Simpson
- Ontario Clean Water Agency, 1 Yonge Street, Suite 1700, Toronto, Ontario, Canada M5E 1E5.
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