A successful design, previously adapted for treatment of complex wastewaters in a microbial fuel cell(MFC),was used to fabricate two MFCs, with a few changes for cost reduction and ease of construction. Performance an...A successful design, previously adapted for treatment of complex wastewaters in a microbial fuel cell(MFC),was used to fabricate two MFCs, with a few changes for cost reduction and ease of construction. Performance and electrochemical characteristics of MFCs were evaluated in different environmental conditions(in complete darkness and presence of light), and different flow patterns of batch and continuous in four hydraulic retention times from 8 to 30 h. Changes in chemical oxygen demand, and nitrate and phosphate concentrations were evaluated. In contrast to the microbial fuel cell operated in darkness(D-MFC) with a stable open circuit voltage of 700 mV, presence of light led to growth of other species, and consecutively low and unsteady open circuit voltage. Although the performance of the MFC subjected to light(L-MFC) was quite low and unsteady in dynamic state(internal resistance = 100 Ω, power density = 5.15 W·m^(-3)), it reached power density of 9.2 W·m^(-3) which was close to performance of D-MFC(internal resistance = 50 Ω, power density = 10.3 W·m^(-3)).Evaluated only for D-MFC, the coulombic efficiency observed in batch mode(30%) was quite higher than the maximum acquired in continuous mode(9.6%) even at the highest hydraulic retention time. In this study,changes in phosphate and different types of nitrogen existing in dairy wastewater were investigated for the first time. At hydraulic retention time of 8 h, the orthophosphate concentration in effluent was 84% higher compared to influent. Total nitrogen and total Kjeldahl nitrogen were reduced 70% and 99% respectively at hydraulic retention time of 30 h, while nitrate and nitrite concentrations increased. The microbial electrolysis cell(MEC), revamped from D-MFC, showed the maximum gas production of 0.2 m^3 H_2·m^(-3)·d^(-1) at 700 mV applied voltage.展开更多
A large amount of real complex wastewaters are generated every year,which leads to a great environmental burden.Various treatment technologies were deployed to remove the contaminants in the wastewaters.However,these ...A large amount of real complex wastewaters are generated every year,which leads to a great environmental burden.Various treatment technologies were deployed to remove the contaminants in the wastewaters.However,these actual wastewaters have not been sufficiently treated due to their complex properties,high-concentration organics,incomplete utilization of hard-biodegradable substrates,the high energy input required,etc.Recently,microbial electrolysis cells(MECs),a great potential technology,has emerged for various wastewater treatment,because not only do they demonstrate satisfactory performance during wastewater treatment,but they also generate renewable H2 as a clean energy carrier.Unlike previous reviews,this review introduced the characteristics of every complicated wastewater,and focused on analyzing and summarizing MEC development for wastewater treatment.The performances of MECs were systematically reviewed in terms of organics removal,H2 production,Columbic efficiency,and energy efficiency.MEC performances for treating actual complex wastewaters and producing H2 can be optimized through operation parameters,electrode materials,catalyst materials,etc.In addition,the challenges and opportunities including complexity of wastewaters,instability of H2 production,robust microorganisms,effect of membrane on two-chamber MEC,and integration of MEC with other treatment processes were deeply discussed.Except for the technical feasibility,both environmental feasibility and economic feasibility also need to meet social requirements.This review can indeed provide a basis for high-efficiency treatment and practical commercial applications of recalcitrant wastewaters via MECs in the future.展开更多
Microbial electrochemical technology has drawn increasing attention for the treatment of recalcitrant wastewater as well as production of energy or value-added chemicals recently.However,the study on the treatment of ...Microbial electrochemical technology has drawn increasing attention for the treatment of recalcitrant wastewater as well as production of energy or value-added chemicals recently.However,the study on the treatment of hydrothermal liquefied wastewater(HTL-WW)using microbial electrolysis cell(MEC)is still in its infancy.This study focused on the effects of organic loading rates(OLRs)on the treatment efficiency of recalcitrant HTL-WW and hydrogen production via the MEC.In general,the chemical oxygen demand(COD)removal rate was more than 71.74%at different initial OLRs.Specially,up to 83.84%of COD removal rate was achieved and the volatile fatty acids were almost degraded at the initial OLR of 2 g COD/L·d in the anode of MEC.The maximum hydrogen production rate was 3.92 mL/L·d in MEC cathode,corresponding to a hydrogen content of 7.10%at the initial OLR of 2 g COD/L·d.And in the anode,the maximum methane production rate of 826.87 mL/L·d was reached with its content of 54.75%at the initial OLR of 10 g COD/L·d.Analysis of electrochemical properties showed that the highest open circuit voltage of 0.48 V was obtained at the initial OLR of 10 g COD/L·d,and the maximum power density(1546.22 mW/m3)as well as the maximum coulombic efficiency(6.01%)were obtained at the initial OLR of 8 g COD/L·d.GC-MS analysis revealed the existence of phenols and heterocyclic matters in the HTL-WW,such as 1-acetoxynonadecane and 2,4-bis(1-phenylethyl)-phenol.These recalcitrant compounds in HTL-WW were efficiently removed via MEC,which was probably due to the combination effect of microbial community and electrochemistry in MEC anode.展开更多
The combination of the microbial electrolysis desalination and chemical-production cell(MEDCC)and Fenton process for the pesticide wastewater treatment was investigate in this study.Real wastewater with several toxic ...The combination of the microbial electrolysis desalination and chemical-production cell(MEDCC)and Fenton process for the pesticide wastewater treatment was investigate in this study.Real wastewater with several toxic pesticides,1633 mg/L COD,and 200 in chromaticity was used for the investigation.Results showed that desalination in the desalination chamber of MEDCC reached 78%.Organics with low molecular weights in the desalination chamber could be removed from the desalination chamber,resulting in 28%and 23%of the total COD in the acid-production and cathode chambers,respectively.The desalination in the desalination chamber and organic transfer contributed to removal of pesticides(e.g.,triadimefon),which could not be removed with other methods,and of the organics with low molecular weights.The COD in the effluent of the MEDCC combined the Fenton process was much lower than that in the perixo-coagulaiton process(<150 vs.555 mg/L).The combined method consumed much less energy and acid for the pH adjustment than that the Fenton.展开更多
基金supported by Sharif University of Technology,Vice President for Research Grant G930111
文摘A successful design, previously adapted for treatment of complex wastewaters in a microbial fuel cell(MFC),was used to fabricate two MFCs, with a few changes for cost reduction and ease of construction. Performance and electrochemical characteristics of MFCs were evaluated in different environmental conditions(in complete darkness and presence of light), and different flow patterns of batch and continuous in four hydraulic retention times from 8 to 30 h. Changes in chemical oxygen demand, and nitrate and phosphate concentrations were evaluated. In contrast to the microbial fuel cell operated in darkness(D-MFC) with a stable open circuit voltage of 700 mV, presence of light led to growth of other species, and consecutively low and unsteady open circuit voltage. Although the performance of the MFC subjected to light(L-MFC) was quite low and unsteady in dynamic state(internal resistance = 100 Ω, power density = 5.15 W·m^(-3)), it reached power density of 9.2 W·m^(-3) which was close to performance of D-MFC(internal resistance = 50 Ω, power density = 10.3 W·m^(-3)).Evaluated only for D-MFC, the coulombic efficiency observed in batch mode(30%) was quite higher than the maximum acquired in continuous mode(9.6%) even at the highest hydraulic retention time. In this study,changes in phosphate and different types of nitrogen existing in dairy wastewater were investigated for the first time. At hydraulic retention time of 8 h, the orthophosphate concentration in effluent was 84% higher compared to influent. Total nitrogen and total Kjeldahl nitrogen were reduced 70% and 99% respectively at hydraulic retention time of 30 h, while nitrate and nitrite concentrations increased. The microbial electrolysis cell(MEC), revamped from D-MFC, showed the maximum gas production of 0.2 m^3 H_2·m^(-3)·d^(-1) at 700 mV applied voltage.
基金supported by China Postdoctoral Science Foundation(2018M641295)China Agriculture Research System(CARS-02)National Natural Science Foundation of China(51561145013).
文摘A large amount of real complex wastewaters are generated every year,which leads to a great environmental burden.Various treatment technologies were deployed to remove the contaminants in the wastewaters.However,these actual wastewaters have not been sufficiently treated due to their complex properties,high-concentration organics,incomplete utilization of hard-biodegradable substrates,the high energy input required,etc.Recently,microbial electrolysis cells(MECs),a great potential technology,has emerged for various wastewater treatment,because not only do they demonstrate satisfactory performance during wastewater treatment,but they also generate renewable H2 as a clean energy carrier.Unlike previous reviews,this review introduced the characteristics of every complicated wastewater,and focused on analyzing and summarizing MEC development for wastewater treatment.The performances of MECs were systematically reviewed in terms of organics removal,H2 production,Columbic efficiency,and energy efficiency.MEC performances for treating actual complex wastewaters and producing H2 can be optimized through operation parameters,electrode materials,catalyst materials,etc.In addition,the challenges and opportunities including complexity of wastewaters,instability of H2 production,robust microorganisms,effect of membrane on two-chamber MEC,and integration of MEC with other treatment processes were deeply discussed.Except for the technical feasibility,both environmental feasibility and economic feasibility also need to meet social requirements.This review can indeed provide a basis for high-efficiency treatment and practical commercial applications of recalcitrant wastewaters via MECs in the future.
基金through National Science Foundation of China(21106080,51561145013)Beijing Youth Top-notch Talents Program(2015000026833ZK10).
文摘Microbial electrochemical technology has drawn increasing attention for the treatment of recalcitrant wastewater as well as production of energy or value-added chemicals recently.However,the study on the treatment of hydrothermal liquefied wastewater(HTL-WW)using microbial electrolysis cell(MEC)is still in its infancy.This study focused on the effects of organic loading rates(OLRs)on the treatment efficiency of recalcitrant HTL-WW and hydrogen production via the MEC.In general,the chemical oxygen demand(COD)removal rate was more than 71.74%at different initial OLRs.Specially,up to 83.84%of COD removal rate was achieved and the volatile fatty acids were almost degraded at the initial OLR of 2 g COD/L·d in the anode of MEC.The maximum hydrogen production rate was 3.92 mL/L·d in MEC cathode,corresponding to a hydrogen content of 7.10%at the initial OLR of 2 g COD/L·d.And in the anode,the maximum methane production rate of 826.87 mL/L·d was reached with its content of 54.75%at the initial OLR of 10 g COD/L·d.Analysis of electrochemical properties showed that the highest open circuit voltage of 0.48 V was obtained at the initial OLR of 10 g COD/L·d,and the maximum power density(1546.22 mW/m3)as well as the maximum coulombic efficiency(6.01%)were obtained at the initial OLR of 8 g COD/L·d.GC-MS analysis revealed the existence of phenols and heterocyclic matters in the HTL-WW,such as 1-acetoxynonadecane and 2,4-bis(1-phenylethyl)-phenol.These recalcitrant compounds in HTL-WW were efficiently removed via MEC,which was probably due to the combination effect of microbial community and electrochemistry in MEC anode.
基金This work was partly supported by grants from the National Natural Science Foundation of China(Grant Nos.51278500 and 51308557)the Program of Guangdong Science&Technology Department(No.2017A010104007).
文摘The combination of the microbial electrolysis desalination and chemical-production cell(MEDCC)and Fenton process for the pesticide wastewater treatment was investigate in this study.Real wastewater with several toxic pesticides,1633 mg/L COD,and 200 in chromaticity was used for the investigation.Results showed that desalination in the desalination chamber of MEDCC reached 78%.Organics with low molecular weights in the desalination chamber could be removed from the desalination chamber,resulting in 28%and 23%of the total COD in the acid-production and cathode chambers,respectively.The desalination in the desalination chamber and organic transfer contributed to removal of pesticides(e.g.,triadimefon),which could not be removed with other methods,and of the organics with low molecular weights.The COD in the effluent of the MEDCC combined the Fenton process was much lower than that in the perixo-coagulaiton process(<150 vs.555 mg/L).The combined method consumed much less energy and acid for the pH adjustment than that the Fenton.
基金supported by the National Natural Science Foundation of China(No.21566025 and No.21875253)the Natural Science Foundation of Jiangxi Province(No.20152ACB21019 and No.20162BCB23044)。
