In this study,an up-flow anaerobic sludge blanket(UASB) reactor was applied to treat the high salinity wastewater from heavy oil production process.At a HRT of ≥24 h,the COD removal reached as high as 65.08% at an in...In this study,an up-flow anaerobic sludge blanket(UASB) reactor was applied to treat the high salinity wastewater from heavy oil production process.At a HRT of ≥24 h,the COD removal reached as high as 65.08% at an influent COD ranging from 350mg/L to 640mg/L.An average of 74.33% oil reduction was also achieved in the UASB reactor at an initial oil concentration between 112mg/L and 205mg/L.These results indicated that this heavy oil production related wastewater could be degraded efficiently in the UASB reactor.Granular sludge was formed in this reactor.In addition,two models,built on the back propagation neural network(BPNN) theory and linear regression techniques were developed for the simulation of the UASB system performance in the oily wastewater biodegradation.The average error of COD and oil removal was-0.65% and 0.84%,respectively.The results indicated that the models built on the BPNN theory were wellfitted to the detected data,and were able to simulate and predict the removal of COD and oil by the UASB reactor.展开更多
The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater.However,acetic acid can also be produced from methanol theoretically,which may probably resul...The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater.However,acetic acid can also be produced from methanol theoretically,which may probably result in an abrupt pH drop and deteriorate the anaerobic process.Therefore,it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater.In this study,an up-flow anaerobic sludge bed(UASB)reactor treating methanol wastewater was operated.The chemical oxygen demand(COD),acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity.The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops.Volatile fatty acids accumulation was not observed even at strong shock loadings.The microorganisms in the sludge at the end of the test became homogeneous in morphology,which were mainly spherical or spheroidal in shape.展开更多
Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content.The aim of this paper is to study the effect of wastewater composition on calcium carbonate precipitation in upf...Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content.The aim of this paper is to study the effect of wastewater composition on calcium carbonate precipitation in upflow anaerobic sludge blanket(UASB)reactors.Two laboratory-scale UASB reactors were operated with calcium-containing influents using acetate and carbohydrate as substrate,respectively.There was an obvious accumulation of inorganic precipitate observed in the biogranules.Observations via scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS)showed that the acclimated biogranules in the two reactors differed in microstructure.Calcium carbonate was found to have precipitated on the surface of acetate-degrading biogranules,but precipitated at the core of the carbohydrate-degrading biogranules.The results indicated that substrates had significant influence on the location of calcium carbonate precipitation in anaerobic granular sludge,which was expected due to the different methanogens distribution and pH gradient within the granular sludge degrading various substrates.Moreover,the location of calcium carbonate precipitation substantially affected the specific methanogenic activity(SMA)of the granular sludge.The SMA of the acetate-degrading biogranules dropped from 1.96 gCODCH4·gVSS^(–1)·d^(–1)to 0.61 gCODCH4·gVSS^(–1)·d^(–1)after 180-d of operation in the reactor.However,the SMA of the carbohydrate-degrading biogranules was not adversely affected by calcium carbonate precipitation.展开更多
Treatment of sulfamethoxazole pharmaceutical wastewater is a big challenge.In this study,a series of anaerobic evaluation tests on pharmaceutical wastewater from different operating units was conducted to evaluate the...Treatment of sulfamethoxazole pharmaceutical wastewater is a big challenge.In this study,a series of anaerobic evaluation tests on pharmaceutical wastewater from different operating units was conducted to evaluate the feasibility of using anaerobic digestion,and the results indicated that the key refractory factor for anaerobic treatment of this wastewater was the high sulfate concentration.A laboratory-scale up-flow anaerobic sludge blanket(UASB)reactor was operated for 195 days to investigate the effects of the influent chemical oxygen demand(COD),organic loading rate(OLR),and COD/SO_(4)^(2-) ratio on the biodegradation of sulfamethoxazole in pharmaceutical wastewater and the process performance.The electron flow indicated that methanogenesis was still the dominant reaction although sulfidogenesis was enhanced with a stepwise decrease in the influent COD/SO_(4)^(2-) ratio.For the treated sulfamethoxazole pharmaceutical wastewater,a COD of 4983 mg/L(diluted by 50%),OLR of 2.5 kg COD/(m^(3)·d),and COD/SO_(4)^(2-) ratio of more than 5 were suitable for practical applications.The recovery performance indicated that the system could resume operation quickly even if production was halted for a few days.展开更多
In this study,the effects of organic sulfur on anaerobic biological processes were investigated by operating two up-flow anaerobic sludge blanket(UASB)reactors with sodium dodecylbenzene sulfonate(SDBS)as a representa...In this study,the effects of organic sulfur on anaerobic biological processes were investigated by operating two up-flow anaerobic sludge blanket(UASB)reactors with sodium dodecylbenzene sulfonate(SDBS)as a representative of organic sulfur.The results indicated that the specific methanogenic activity(SMA)and chemical oxygen demand(COD)removal efficiency of R2(with SDBS added)were higher than those of R1(without SDBS)when the COD/SO_(4)^(2−)ratio was above 5.0.However,when the COD/SO_(4)^(2−)ratio was lower than 5.0,the sulfate reduction efficiency of R2 was higher than that of R1.These results and the observed SDBS transformation efficiency in anaerobic reactors indicate that low concentrations of SDBS accelerate methane production and the continuous accumulation of SDBS does not weaken the reduction of sulfate.Similarly,the calculated electron flux for a COD/SO_(4)^(2−)ratio of 1.0 indicates that the utilization intensity of electrons by sulfate-reducing bacteria(SRB)in R2 was 36.48%higher than that of SRB in R1 and exceeded that of methane-producing archaea(MPA)under identical working conditions.Moreover,the addition of SDBS in R2 made sulfidogenesis the dominant reaction at low COD/SO_(4)^(2−),and Methanobacterium and Methanobrevibacter with H_(2)/CO_(2)as the substrate and Desulfomicrobium were the dominant MPA and SRB,respectively.However,methanogenesis was still the dominant reaction in R1,and Methanosaeta with acetic acid as the substrate and Desulfovibrio were the dominant MPA and SRB,respectively.展开更多
Kinetics of municipal sewage degradation in Expanded Granular Sludge Bed(EGSB)and Up-flow Anaerobic Sludge Blanket(UASB)reactors at 10℃ were investigated via continuous experimental equipments.The results indicated t...Kinetics of municipal sewage degradation in Expanded Granular Sludge Bed(EGSB)and Up-flow Anaerobic Sludge Blanket(UASB)reactors at 10℃ were investigated via continuous experimental equipments.The results indicated that the whole reaction process can be simulated by the first-order dynamic equation model.Dynamic parameters such as k,Vmax and Ks of UASB in hydrolysis acidification stage were 1.08 d-1,2.8 d-1 and 372 mg/L comparing to those of 1.18 d-1,3.5 d-1 and 112 mg/L in the methanogenesis stage respectively.The EGSB’s k,Vmax and Ks were 2.91 d-1,14.3 d-1 and 470 mg/L in the hydrolysis acidification stage comparing to those of 1.68 d-1,6.6 d-1 and 103 mg/L in the methanogenesis stage respectively.Comparison of k values of the two stages in UASB and EGSB indicates that hydrolysis acidification stage is the controlling step for the whole reaction process of UASB,while methanogenesis stage is the controlling step in EGSB.Compared with UASB,municipal sewage treatment by EGSB at 10 ℃ can reach the same effluent requirement with lower retention time due to its effluent recirculation.展开更多
基金the support provided by the Research & Technology Development Project of China National Petroleum Corporation (06A0302)Postdoctor Innovation Funds in Shandong Province (201002039)the Fundamental Research Funds for the Central Universities (27R1204023A)
文摘In this study,an up-flow anaerobic sludge blanket(UASB) reactor was applied to treat the high salinity wastewater from heavy oil production process.At a HRT of ≥24 h,the COD removal reached as high as 65.08% at an influent COD ranging from 350mg/L to 640mg/L.An average of 74.33% oil reduction was also achieved in the UASB reactor at an initial oil concentration between 112mg/L and 205mg/L.These results indicated that this heavy oil production related wastewater could be degraded efficiently in the UASB reactor.Granular sludge was formed in this reactor.In addition,two models,built on the back propagation neural network(BPNN) theory and linear regression techniques were developed for the simulation of the UASB system performance in the oily wastewater biodegradation.The average error of COD and oil removal was-0.65% and 0.84%,respectively.The results indicated that the models built on the BPNN theory were wellfitted to the detected data,and were able to simulate and predict the removal of COD and oil by the UASB reactor.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20376066 and 20436040).
文摘The direct conversion of methanol into methane is the main process in anaerobic treatment of methanol containing wastewater.However,acetic acid can also be produced from methanol theoretically,which may probably result in an abrupt pH drop and deteriorate the anaerobic process.Therefore,it is interesting to know what would really happen in an anaerobic reactor treating methanol wastewater.In this study,an up-flow anaerobic sludge bed(UASB)reactor treating methanol wastewater was operated.The chemical oxygen demand(COD),acetic acid and pH of the effluent were monitored at different loadings and influent alkalinity.The results showed that the anaerobic reactor could be operated steadily at as low as 119 mg/L of influent alkalinity and high organic loading rate with no obvious pH drops.Volatile fatty acids accumulation was not observed even at strong shock loadings.The microorganisms in the sludge at the end of the test became homogeneous in morphology,which were mainly spherical or spheroidal in shape.
基金the National Science and Technology Major Special“Water Pollution Control and Governance”of China(No.2009ZX07212-002-002)the National Natural Science Foundation of China(Grant No.20946001)+1 种基金the Science and Technology Development Program of Shanxi Province in China(No.2006kz08-G2)the Fundamental Research Funds for the Central Universities.
文摘Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content.The aim of this paper is to study the effect of wastewater composition on calcium carbonate precipitation in upflow anaerobic sludge blanket(UASB)reactors.Two laboratory-scale UASB reactors were operated with calcium-containing influents using acetate and carbohydrate as substrate,respectively.There was an obvious accumulation of inorganic precipitate observed in the biogranules.Observations via scanning electron microscope(SEM)and energy dispersive spectroscopy(EDS)showed that the acclimated biogranules in the two reactors differed in microstructure.Calcium carbonate was found to have precipitated on the surface of acetate-degrading biogranules,but precipitated at the core of the carbohydrate-degrading biogranules.The results indicated that substrates had significant influence on the location of calcium carbonate precipitation in anaerobic granular sludge,which was expected due to the different methanogens distribution and pH gradient within the granular sludge degrading various substrates.Moreover,the location of calcium carbonate precipitation substantially affected the specific methanogenic activity(SMA)of the granular sludge.The SMA of the acetate-degrading biogranules dropped from 1.96 gCODCH4·gVSS^(–1)·d^(–1)to 0.61 gCODCH4·gVSS^(–1)·d^(–1)after 180-d of operation in the reactor.However,the SMA of the carbohydrate-degrading biogranules was not adversely affected by calcium carbonate precipitation.
基金supported by the Fundamental Research Funds for the Central Universities(No.2015XKMS053).
文摘Treatment of sulfamethoxazole pharmaceutical wastewater is a big challenge.In this study,a series of anaerobic evaluation tests on pharmaceutical wastewater from different operating units was conducted to evaluate the feasibility of using anaerobic digestion,and the results indicated that the key refractory factor for anaerobic treatment of this wastewater was the high sulfate concentration.A laboratory-scale up-flow anaerobic sludge blanket(UASB)reactor was operated for 195 days to investigate the effects of the influent chemical oxygen demand(COD),organic loading rate(OLR),and COD/SO_(4)^(2-) ratio on the biodegradation of sulfamethoxazole in pharmaceutical wastewater and the process performance.The electron flow indicated that methanogenesis was still the dominant reaction although sulfidogenesis was enhanced with a stepwise decrease in the influent COD/SO_(4)^(2-) ratio.For the treated sulfamethoxazole pharmaceutical wastewater,a COD of 4983 mg/L(diluted by 50%),OLR of 2.5 kg COD/(m^(3)·d),and COD/SO_(4)^(2-) ratio of more than 5 were suitable for practical applications.The recovery performance indicated that the system could resume operation quickly even if production was halted for a few days.
基金the Fundamental Research Funds for the Central Universities(2019XKQYMS78)for the support of this study.
文摘In this study,the effects of organic sulfur on anaerobic biological processes were investigated by operating two up-flow anaerobic sludge blanket(UASB)reactors with sodium dodecylbenzene sulfonate(SDBS)as a representative of organic sulfur.The results indicated that the specific methanogenic activity(SMA)and chemical oxygen demand(COD)removal efficiency of R2(with SDBS added)were higher than those of R1(without SDBS)when the COD/SO_(4)^(2−)ratio was above 5.0.However,when the COD/SO_(4)^(2−)ratio was lower than 5.0,the sulfate reduction efficiency of R2 was higher than that of R1.These results and the observed SDBS transformation efficiency in anaerobic reactors indicate that low concentrations of SDBS accelerate methane production and the continuous accumulation of SDBS does not weaken the reduction of sulfate.Similarly,the calculated electron flux for a COD/SO_(4)^(2−)ratio of 1.0 indicates that the utilization intensity of electrons by sulfate-reducing bacteria(SRB)in R2 was 36.48%higher than that of SRB in R1 and exceeded that of methane-producing archaea(MPA)under identical working conditions.Moreover,the addition of SDBS in R2 made sulfidogenesis the dominant reaction at low COD/SO_(4)^(2−),and Methanobacterium and Methanobrevibacter with H_(2)/CO_(2)as the substrate and Desulfomicrobium were the dominant MPA and SRB,respectively.However,methanogenesis was still the dominant reaction in R1,and Methanosaeta with acetic acid as the substrate and Desulfovibrio were the dominant MPA and SRB,respectively.
基金This work was supported by the Project of Science and Technology Commission of Shanghai Municipality(No.042312076,062R14089)the Key Technologies Research and Development Program(No.2003BA808A17)the High Tech Research and Development(863)Program(No.2004AA649310)
文摘Kinetics of municipal sewage degradation in Expanded Granular Sludge Bed(EGSB)and Up-flow Anaerobic Sludge Blanket(UASB)reactors at 10℃ were investigated via continuous experimental equipments.The results indicated that the whole reaction process can be simulated by the first-order dynamic equation model.Dynamic parameters such as k,Vmax and Ks of UASB in hydrolysis acidification stage were 1.08 d-1,2.8 d-1 and 372 mg/L comparing to those of 1.18 d-1,3.5 d-1 and 112 mg/L in the methanogenesis stage respectively.The EGSB’s k,Vmax and Ks were 2.91 d-1,14.3 d-1 and 470 mg/L in the hydrolysis acidification stage comparing to those of 1.68 d-1,6.6 d-1 and 103 mg/L in the methanogenesis stage respectively.Comparison of k values of the two stages in UASB and EGSB indicates that hydrolysis acidification stage is the controlling step for the whole reaction process of UASB,while methanogenesis stage is the controlling step in EGSB.Compared with UASB,municipal sewage treatment by EGSB at 10 ℃ can reach the same effluent requirement with lower retention time due to its effluent recirculation.
