In this study, a full-scale internal circulation（IC） reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste（MSW）incineration plant, in which ...In this study, a full-scale internal circulation（IC） reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste（MSW）incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates（OLR） of 21.06–25.16 kg chemical oxygen demand（COD）/（m3？ day）. The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances（EPS） was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid（VSS） during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy（3 D-EEM） and Fourier transform infrared spectroscopy（FT-IR）analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation.展开更多
Sludge granulation and the effect of gas-liquid-solid separator （GLSS） design on the efficiency of upflow anaerobic sludge blanket （UASB） and upflow anaerobic sludge filter （UASF） reactors, operating at HRTs ran...Sludge granulation and the effect of gas-liquid-solid separator （GLSS） design on the efficiency of upflow anaerobic sludge blanket （UASB） and upflow anaerobic sludge filter （UASF） reactors, operating at HRTs ranging from 3 to 12 h was investigated. VSS/TS ratio gradually increased in both the reactors with increasing sludge age （from 0.5 to more than 0.7 for UASB reactor and 0.012 to 0.043 for UASF reactor）. X-Ray diffraction analysis of the UASF sludge showed the presence of expanding clays revealing its additional absorption capability. Fuoraphyllite and albite precipitation related to excellular polymers of the microbial shell structure, showed the extended growth of microorganisms during sludge granulation. A gradual decrease （82%-69%） in COD removal with decreasing HRT was apparent in UASF reactor. In case of UASB reactor, this decrease was marginal because addition of GLSS device significantly improved （14%-20%） the overall efficiency of the UASB reactor. GLSS enhanced the efficiency of the UASB reactor by increasing the settleability of suspended particles and accelerating the coagulation of colloidal particles due to the velocity gradient.展开更多
Four reactors of up-flow anaerobic sludge blanket (UASB) were concurrentlyoperated to examine the effects of the xonotlite secondary particles on promoting the sludgegranulation during the starting-up stage at room te...Four reactors of up-flow anaerobic sludge blanket (UASB) were concurrentlyoperated to examine the effects of the xonotlite secondary particles on promoting the sludgegranulation during the starting-up stage at room temperature. The results show that the putting ofthe xonotlite secondary particles into the UASB reactors can increase the basicity of the reactingliquid significantly. The particles can act as the media for biomass accumulation. Thus, thegranulation process of the sludge within the reactor can be largely promoted by the specialperformances of the particles both in physical and chemical aspects.展开更多
Three UASB reactors were operated to investigate the population dynamics of anaerobic sludge granulation. It is found that the increase of bacterial population relates to the bacterial status in anaerobic food chain a...Three UASB reactors were operated to investigate the population dynamics of anaerobic sludge granulation. It is found that the increase of bacterial population relates to the bacterial status in anaerobic food chain and relates to sludge organic loading rates. In order to form granular sludge, it is necessary to have sufficient amount of different groups of bacteria in the sludge. In our experiment, the population of fermentative bacteria, propionate degraders, butyrate degraders and methanogens is about 107-8, 105-7, 105-7 and 105-7 cells/ml respectively at the appearance of granular sludge. Filamentous methanogenic bacteria are found to be the important species in sludge granulation. Based on the results obtained, a descriptive model is proposed to describe the microbial characteristics of granulation.展开更多
[Objective]We aimed to discuss the optimal conditions of sludge granulation on the basis of IC reactor.[Method]By using the formulated glucose wastewater,we studied the rapid cultivation of granular sludge as well as ...[Objective]We aimed to discuss the optimal conditions of sludge granulation on the basis of IC reactor.[Method]By using the formulated glucose wastewater,we studied the rapid cultivation of granular sludge as well as its influencing factors,so as to discuss the optimal conditions of sludge granulation.[Result]Through the static culture outside of IC reactor and dynamic culture in IC reactor,granular sludge appeared within a training cycle,with particle size of 1.0-1.5 mm.In IC reactor,when COD concentration of influent water was 5 000 mg /L,rising velocity was 0.9 m /h,pH was around 7,and auxiliary materials (like flocculant and active carbon) and mature granular sludge were added to the actor during the training process,the granulation process of sludge was accelerated.[Conclusion]The research could provide references for the rapid start-up of IC reactor.展开更多
Effective cultivation of stable aerobic granular sludge(AGS)is a crucial step in the successful application of this technology,and the formation of AGS could be facilitated by some environmental stress conditions.Four...Effective cultivation of stable aerobic granular sludge(AGS)is a crucial step in the successful application of this technology,and the formation of AGS could be facilitated by some environmental stress conditions.Four identical sequencing batch reactors(SBRs)were established to investigate the aerobic granulation process under the same alternating ammonia nitrogen feeding strategy superimposed with different environmental conditions(inorganic carbon source,temperature,N/COD).Although various superimposed conditions induced a significant difference in the size,settling velocity,mechanic strength of AGS,mature aerobic granules could be successfully obtained in all four reactors after 70 days’operation,indicating the alternating ammonia nitrogen feeding strategy was the most critical factor for AGS formation.Based on the results of redundancy analysis,the presence of an inorganic carbon source could facilitate the cultivation of AGS with nitrification function,while the moderate temperature and fluctuant N/COD might benefit the cultivation of more stable AGS.In addition,superimposed stress conditions could result in the difference in the microbial population between four reactors,but the population diversity and abundance of microorganisms were not the determinants of AGS formation.This study provided an effective method for the cultivation of AGS by using alternating ammonia nitrogen feeding strategy.展开更多
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
A new anaerobic reactor, Jet-loop anaerobic fluidized bed （JLAFB）, was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO42 ratio and alkalinity and...A new anaerobic reactor, Jet-loop anaerobic fluidized bed （JLAFB）, was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO42 ratio and alkalinity and sulfide inhibition in reactors, were discussed for a JLAFB and a general anaerobic fiuidized bed （AFB） reactor used as sulfate-reducing phase and methane-producing phase, respectively, in two-phase anaerobic digestion process. The formation of granules in the two reactors was also examined. The results indicated that COD and sulfate removal had different demand of influent COD/SO4^2- ratios. When total COD removal was up to 85%, the ratio was only required up to 1.2, whereas, total sulfate removal up to 95% required it exceeding 3.0. The alkalinity in the two reactors increased linearly with the growth of influent alkalinity. Moreover, the change of influent alkalinity had no significant effect on pH and volatile fatty acids （VFA） in the two reactors. Influent alkalinity kept at 400-500 mg/L could meet the requirement of the treating process. The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms. When sulfate loading rate was up to 8. 1 kg/（m^3.d）, the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L, respectively. Furthermore, the granules, with offwhite color, ellipse shape and diameters of 1.0-3.0 mm, could be developed in JLAFB reactor. In granules, different groups of bacteria were distributed in different layers, and some inorganic metal compounds such as Fe, Ca, Mg etc. were found.展开更多
A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose w...A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose wastewater treatment. With the wastewater recycle ratio of 2.5 ： 1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the JBILAFB reactor could be completed in less than 70 d through maintenance of hydraulic retention time （HR^I＂） and stepwise increase of feed total organic carbon （TOC） concentration. After the start-up, with the volumetric TOC loadings of 14.3 kg·m ^-3·d^-1, the TOC removal ratio, the effluent pH, and the volatile fatty acids （VFA）/alkalinity of the JBILAFB reactor were more than 80%, close to 7.0 and less than 0.4, respectively. Moreover, CH4 was produced at more than 70% of the theoretical value, The reactor exhibited high stability under the condition of high volumetric TOC loading. Sludge granules in the JBILAFB reactor were developed during the start-up and their sizes were enlarged with the stepwise increase of volumetric TOC loadings from 0.8 kg.m^-3.d ^-1 to 14.3 kg.m^-3.d^-1. Granules, an offwhite color and a similar spherical shape, were mainly comprised of global-like bacteria. These had good methanogenic activity and settleability, which were formed probably through adhesion of the bacteria. Some inorganic metal compounds such as Fe, Ca, Mg, Al, etc. were advantageous to the formation of the granules.展开更多
The sequencing batch reactor (SBR) was started up by seeding the anaerobic granular sludge and the aerobic granular sludge was successfully cultivated. The performance characteristic of the aerobic granules for nitrog...The sequencing batch reactor (SBR) was started up by seeding the anaerobic granular sludge and the aerobic granular sludge was successfully cultivated. The performance characteristic of the aerobic granules for nitrogen removal was investigated in detail. The experimental results demonstrated the relationship between operational parameters [dissolved oxygen (DO) and pH] and variation of chemical oxygen demand (COD), ammonium (NH4+-N)and total nitrogen (TN). In continuous flow pattern, COD was too low in the reactor at the later stage of a cycle,which restrained denitrification and decreased the removal of nitrogen, while in discontinuous flow pattern, the carbon source could be supplemented in time, which improved denitrification and increased the removal of TN from 66% to 81%.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21506076,51678279 and 51508230)the National Science and Technological Support of China(No.2014BAC25B01)
文摘In this study, a full-scale internal circulation（IC） reactor coupled with an external circulation system was developed to treat high-strength leachate from a municipal solid waste（MSW）incineration plant, in which anaerobic sludge granulation was intensively investigated. Results showed that the IC reactor achieved excellent treatment performance under high organic loading rates（OLR） of 21.06–25.16 kg chemical oxygen demand（COD）/（m3？ day）. The COD removal efficiency and biogas yield respectively reached 89.4%–93.4% and 0.42–0.50 m3/kg COD.The formation of extracellular polymeric substances（EPS） was closely associated with sludge granulation. Protein was the dominant component in sludge EPS, and its content was remarkably increased from 21.6 to 99.7 mg/g Volatile Suspended Solid（VSS） during the reactor operation. The sludge Zeta potential and hydrophobicity positively correlated with the protein/polysaccharide ratio in EPS, and they were respectively increased from-26.2 m V and 30.35% to-10.6 m V and 78.67%, which was beneficial to microbial aggregation. Three-dimensional fluorescence spectroscopy（3 D-EEM） and Fourier transform infrared spectroscopy（FT-IR）analysis further indicated the importance of protein-like EPS substances in the sludge granulation. Moreover, it was also found that the secondary structures of EPS proteins varied during the reactor operation.
文摘Sludge granulation and the effect of gas-liquid-solid separator （GLSS） design on the efficiency of upflow anaerobic sludge blanket （UASB） and upflow anaerobic sludge filter （UASF） reactors, operating at HRTs ranging from 3 to 12 h was investigated. VSS/TS ratio gradually increased in both the reactors with increasing sludge age （from 0.5 to more than 0.7 for UASB reactor and 0.012 to 0.043 for UASF reactor）. X-Ray diffraction analysis of the UASF sludge showed the presence of expanding clays revealing its additional absorption capability. Fuoraphyllite and albite precipitation related to excellular polymers of the microbial shell structure, showed the extended growth of microorganisms during sludge granulation. A gradual decrease （82%-69%） in COD removal with decreasing HRT was apparent in UASF reactor. In case of UASB reactor, this decrease was marginal because addition of GLSS device significantly improved （14%-20%） the overall efficiency of the UASB reactor. GLSS enhanced the efficiency of the UASB reactor by increasing the settleability of suspended particles and accelerating the coagulation of colloidal particles due to the velocity gradient.
基金This work was supported by the National Natural Science Foundation of China (No.50172009).
文摘Four reactors of up-flow anaerobic sludge blanket (UASB) were concurrentlyoperated to examine the effects of the xonotlite secondary particles on promoting the sludgegranulation during the starting-up stage at room temperature. The results show that the putting ofthe xonotlite secondary particles into the UASB reactors can increase the basicity of the reactingliquid significantly. The particles can act as the media for biomass accumulation. Thus, thegranulation process of the sludge within the reactor can be largely promoted by the specialperformances of the particles both in physical and chemical aspects.
文摘Three UASB reactors were operated to investigate the population dynamics of anaerobic sludge granulation. It is found that the increase of bacterial population relates to the bacterial status in anaerobic food chain and relates to sludge organic loading rates. In order to form granular sludge, it is necessary to have sufficient amount of different groups of bacteria in the sludge. In our experiment, the population of fermentative bacteria, propionate degraders, butyrate degraders and methanogens is about 107-8, 105-7, 105-7 and 105-7 cells/ml respectively at the appearance of granular sludge. Filamentous methanogenic bacteria are found to be the important species in sludge granulation. Based on the results obtained, a descriptive model is proposed to describe the microbial characteristics of granulation.
基金Supported by University Students' Innovation Project of Jiangsu Province,China (166201100022 )Scientific Research Foundation of Nanjing Institute of Technology (QKJC2010011)Science and Technology Support (Industrial) Project of Jiangsu Province,China(BE2010203)
文摘[Objective]We aimed to discuss the optimal conditions of sludge granulation on the basis of IC reactor.[Method]By using the formulated glucose wastewater,we studied the rapid cultivation of granular sludge as well as its influencing factors,so as to discuss the optimal conditions of sludge granulation.[Result]Through the static culture outside of IC reactor and dynamic culture in IC reactor,granular sludge appeared within a training cycle,with particle size of 1.0-1.5 mm.In IC reactor,when COD concentration of influent water was 5 000 mg /L,rising velocity was 0.9 m /h,pH was around 7,and auxiliary materials (like flocculant and active carbon) and mature granular sludge were added to the actor during the training process,the granulation process of sludge was accelerated.[Conclusion]The research could provide references for the rapid start-up of IC reactor.
基金supported by the National Natural Science Foundation of China(No.42077213)the Natural Science Foundation of Shanghai(Nos.19ZR1403700 and 20ZR1406100).
文摘Effective cultivation of stable aerobic granular sludge(AGS)is a crucial step in the successful application of this technology,and the formation of AGS could be facilitated by some environmental stress conditions.Four identical sequencing batch reactors(SBRs)were established to investigate the aerobic granulation process under the same alternating ammonia nitrogen feeding strategy superimposed with different environmental conditions(inorganic carbon source,temperature,N/COD).Although various superimposed conditions induced a significant difference in the size,settling velocity,mechanic strength of AGS,mature aerobic granules could be successfully obtained in all four reactors after 70 days’operation,indicating the alternating ammonia nitrogen feeding strategy was the most critical factor for AGS formation.Based on the results of redundancy analysis,the presence of an inorganic carbon source could facilitate the cultivation of AGS with nitrification function,while the moderate temperature and fluctuant N/COD might benefit the cultivation of more stable AGS.In addition,superimposed stress conditions could result in the difference in the microbial population between four reactors,but the population diversity and abundance of microorganisms were not the determinants of AGS formation.This study provided an effective method for the cultivation of AGS by using alternating ammonia nitrogen feeding strategy.
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Project supported by the National Natural Science Foundation of China(No. 50278036)the Natural Science Foundation of Guangdong Province (No. 04105951)
文摘A new anaerobic reactor, Jet-loop anaerobic fluidized bed （JLAFB）, was designed for treating high-sulfate wastewater. The treatment characteristics, including the effect of influent COD/SO42 ratio and alkalinity and sulfide inhibition in reactors, were discussed for a JLAFB and a general anaerobic fiuidized bed （AFB） reactor used as sulfate-reducing phase and methane-producing phase, respectively, in two-phase anaerobic digestion process. The formation of granules in the two reactors was also examined. The results indicated that COD and sulfate removal had different demand of influent COD/SO4^2- ratios. When total COD removal was up to 85%, the ratio was only required up to 1.2, whereas, total sulfate removal up to 95% required it exceeding 3.0. The alkalinity in the two reactors increased linearly with the growth of influent alkalinity. Moreover, the change of influent alkalinity had no significant effect on pH and volatile fatty acids （VFA） in the two reactors. Influent alkalinity kept at 400-500 mg/L could meet the requirement of the treating process. The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms. When sulfate loading rate was up to 8. 1 kg/（m^3.d）, the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L, respectively. Furthermore, the granules, with offwhite color, ellipse shape and diameters of 1.0-3.0 mm, could be developed in JLAFB reactor. In granules, different groups of bacteria were distributed in different layers, and some inorganic metal compounds such as Fe, Ca, Mg etc. were found.
基金Supported by the National Natural Science Foundation of China （No.50278036）, the Natural Science Foundation of Guangdong Province （No.04105951） and the National High Technology Research and Development Program of China （No.2006AA06Z378）.
文摘A novel anaerobic reactor, jet biogas inter-loop anaerobic fluidized bed （JBILAFB）, was designed and constructed. The start-up and performance of the reactor was investigated in the Process. of .artificial glucose wastewater treatment. With the wastewater recycle ratio of 2.5 ： 1, the recycled wastewater with biogas could mix sludge and wastewater in the JBILAFB reactor completely. The start-up of the JBILAFB reactor could be completed in less than 70 d through maintenance of hydraulic retention time （HR^I＂） and stepwise increase of feed total organic carbon （TOC） concentration. After the start-up, with the volumetric TOC loadings of 14.3 kg·m ^-3·d^-1, the TOC removal ratio, the effluent pH, and the volatile fatty acids （VFA）/alkalinity of the JBILAFB reactor were more than 80%, close to 7.0 and less than 0.4, respectively. Moreover, CH4 was produced at more than 70% of the theoretical value, The reactor exhibited high stability under the condition of high volumetric TOC loading. Sludge granules in the JBILAFB reactor were developed during the start-up and their sizes were enlarged with the stepwise increase of volumetric TOC loadings from 0.8 kg.m^-3.d ^-1 to 14.3 kg.m^-3.d^-1. Granules, an offwhite color and a similar spherical shape, were mainly comprised of global-like bacteria. These had good methanogenic activity and settleability, which were formed probably through adhesion of the bacteria. Some inorganic metal compounds such as Fe, Ca, Mg, Al, etc. were advantageous to the formation of the granules.
文摘The sequencing batch reactor (SBR) was started up by seeding the anaerobic granular sludge and the aerobic granular sludge was successfully cultivated. The performance characteristic of the aerobic granules for nitrogen removal was investigated in detail. The experimental results demonstrated the relationship between operational parameters [dissolved oxygen (DO) and pH] and variation of chemical oxygen demand (COD), ammonium (NH4+-N)and total nitrogen (TN). In continuous flow pattern, COD was too low in the reactor at the later stage of a cycle,which restrained denitrification and decreased the removal of nitrogen, while in discontinuous flow pattern, the carbon source could be supplemented in time, which improved denitrification and increased the removal of TN from 66% to 81%.
