The anaerobic ammonia oxidation(Anammox) granular sludge bed reactor was started up successfully with nitrifying granular sludge. During the operation, the nitrifying granular sludge was gradually converted into Anamm...The anaerobic ammonia oxidation(Anammox) granular sludge bed reactor was started up successfully with nitrifying granular sludge. During the operation, the nitrifying granular sludge was gradually converted into Anammox granular sludge with good settling property and high conversion activity. The Anammox reactor worked well with the shortest HRT of 2 43 h. Under the condition that HRT w as 6 39 h and influent concentration of ammonia and nitrite was 10 mmol/L, the removal of ammonia and nitrite was 97 17% and 100 00%, respectively. Corresponding volumetric total nitrogen loading rate and volumetric total nitrogen conversion rate were 100 83 mmol/(L·d) and 98 95 mmol/(L·d). The performance of Anammox reactor was efficient and stable.展开更多
This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L^-1(Na^+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At ...This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L^-1(Na^+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L^-1(Na^+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L^-1.h^-1, 28.04-28.97ml·g^-1, 7.52-7.83ml·g^-1.h^-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g^-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.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
This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the op...This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the opti- mum sodium ion concentration [1000—2000mg·L-1(Na+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6— 413.1mg·L-1·h-1, 28.04—28.97ml·g-1, 7.52—7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.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
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
Bed expansion serves an important function in the design and operation of an upflow anaerobic reactor. An analysis of the flow pattern of expanded granular sludge bed (EGSB) reactors shows that most EGSB reactors do...Bed expansion serves an important function in the design and operation of an upflow anaerobic reactor. An analysis of the flow pattern of expanded granular sludge bed (EGSB) reactors shows that most EGSB reactors do not behave as expanded bed reactors, as is widely perceived. Rather, these reactors behave as fluidized bed reactors based on the classic chemical reactor theory. In this paper, four bed expansion modes, divided as static bed, expanded bed, suspended bed, and fluidized bed, for bioreactors are proposed. A high-rate anaerobic suspended granular sludge bed (SGSB) reactor was then developed. The SGSB reactor is an upflow anaerobic reactor, and its expansion degree can be easily controlled within a range to maintain the suspended status of the sludge bed by controlling upfiow velocity. The results of the full-scale reactor confirmed that the use of SGSB reactors is advantageous. The full-scale SGSB reactor runs stably and achieves high COD removal efficiency (about 90%) at high loading rates (average 40 kg-COD·m^-3·d^-1, maximum to 52 kg·COD·m^-3 ·d^-1) based on the SGSB theory, and its expansion degree is between 22% and 37%.展开更多
An expanded granular sludge bed (EGSB) reactor was adopted to study the influence factors and rule of enhancing granular sludge concentration and performance. The experiment was performed at 33 ℃, pH 6.0-8.0 with c...An expanded granular sludge bed (EGSB) reactor was adopted to study the influence factors and rule of enhancing granular sludge concentration and performance. The experiment was performed at 33 ℃, pH 6.0-8.0 with continuous flow by adding proper quantity of nutritional trace elements. The results show that SLR was the key of steady operation of EGSB reactor. The increment of the granular sludge was influenced by volume loading rate (VLR), liquid up-flow velocity and sludge loading rate (SLR). Concentration of granular sludge increased rapidly when liquid up-flow velocity was over 0.94 m · h^-1 with SLR being at 1.0-2.0 d ^-1. With the propriety parameters: liquid up-flow velocity 2.52 m · h^-1, SLR 1.0-2.2 d^-1 and VLR 8.2-13.1 kg · m ^3 · d^-1, 23 days' continuous operation resulted in an increment by over 80% of granular sludge concentration in the EGSB reactor, plus good granular sludge property.展开更多
A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a convention...A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.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
A two-phase anaerobic reactor fed with glucose substrate(3 g chemical oxygen demand(COD)/L) was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product(SMP...A two-phase anaerobic reactor fed with glucose substrate(3 g chemical oxygen demand(COD)/L) was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product(SMP) formation. Low concentrations of Ni(II)(5 and10 mg/L) promoted the acid phase, whereas high concentrations(15, 20, and 25 mg/L)exhibited an inhibitory effect on, but did not alter the fermentative method, which mainly involved the fermentation of propionic acid. The methanogenic microorganism exhibited a strong capability adapting constantly increased Ni(II) levels. The acid phase was an accumulation stage of SMP. In the absence of Ni(II), the high-molecular-weight material in the effluent SMP mainly contained polysaccharide, tryptophan, and casein. Methanogens metabolized most of the polysaccharide, the whole tryptophan content, and part of the casein, leading to the presence of humic acid and protein in effluent. After Ni(II) dosage, the protein and polysaccharide of the acid phase increased, and tryptophan changed, while casein remained stable. More protein than polysaccharide was produced, suggesting the prominent function of protein when addressing the negative effect of toxic metals. The analysis of DNA confirmed the change of bacterial activity.展开更多
The stability of performance of anaerobic ammonium oxidation (ANAMMOX) reactors was studied and the indices of performance stability were compared.The results showed that under different types of shock load, the react...The stability of performance of anaerobic ammonium oxidation (ANAMMOX) reactors was studied and the indices of performance stability were compared.The results showed that under different types of shock load, the reactors with different configurations displayed different stability.The biofilm reactor stood first in stability towards substrate shock load, followed by anaerobic sequencing batch reactor (SBR) and the granular sludge bed.And the biofilm reactor took the first place towards hydraulic shock load, followed by the granular sludge bed and SBR.The three ANAMMOX reactors were more tolerant to hydraulic shock load than to substrate shock load.When different kinds of stability assessment indices(i.e., sensitivity ratio, mean variance ratio and derivative regression function) were used, inconsistent assessment conclusions were reached.It was suggested that the mean deviation ratio and derivative regression function were more effective and universal.展开更多
针对A^2/O+移动床生物膜反应器(A^2/O+MBBR)双污泥系统,以低碳氮比(C/N)生活污水为处理对象,考察启动过程的污泥特性和反硝化除磷特性,基于脱氮除磷的代谢机理建立系统的快速启动策略。研究结果表明:启动过程历时21 d完成,污泥结构稳定...针对A^2/O+移动床生物膜反应器(A^2/O+MBBR)双污泥系统,以低碳氮比(C/N)生活污水为处理对象,考察启动过程的污泥特性和反硝化除磷特性,基于脱氮除磷的代谢机理建立系统的快速启动策略。研究结果表明:启动过程历时21 d完成,污泥结构稳定且具有较好的污泥沉降性和生物活性;平均重量污泥浓度从1 189 mg/L增加到1 760 mg/L,SVI值在95 m L/g MLSS以下,反硝化聚磷菌(DNPAOs)占聚磷菌(PAOs)的百分比从接种污泥时的10.87%增加到25.46%。启动过程,COD的去除效果基本稳定,A^2/O反应器可实现碳源的高效利用;硝化过程为反硝化除磷提供电子受体,TN的高效去除需要建立在NH+4-N氧化完全的基础上;PO_4^(3-)-P的去除特性与NO_3^--N的变化密切相关,除了缺氧区的同步脱氮除磷,好氧吸磷对稳定PO_4^(3-)-P出水浓度发挥着重要作用。在平均进水碳氮比为3.44的运行条件下,A^2/O+MBBR系统可实现有机物、氮、磷等污染物的同步高效去除,稳定运行阶段出水COD、NH_4^+-N、TN和PO_4^(3-)-P浓度分别为38.5、1.15、14.2、0.15 mg/L,COD、TN和PO_4^(3-)-P去除率分别为82.23%,74.72%和96.80%。DO、pH和ORP等实时控制参数的变化规律与脱氮除磷存在定量关系,稳定运行阶段厌氧区ORP为-398^-336 m V,反硝化过程pH值增幅0.55,ORP增加到-300^-175 m V,硝化过程pH值降低0.37。ORP、pH值可以直观地反映反硝化过程,pH值能够灵敏地反映硝化进程,实时控制参数的联合调控有利于促进系统的快速启动和稳定运行。展开更多
文摘The anaerobic ammonia oxidation(Anammox) granular sludge bed reactor was started up successfully with nitrifying granular sludge. During the operation, the nitrifying granular sludge was gradually converted into Anammox granular sludge with good settling property and high conversion activity. The Anammox reactor worked well with the shortest HRT of 2 43 h. Under the condition that HRT w as 6 39 h and influent concentration of ammonia and nitrite was 10 mmol/L, the removal of ammonia and nitrite was 97 17% and 100 00%, respectively. Corresponding volumetric total nitrogen loading rate and volumetric total nitrogen conversion rate were 100 83 mmol/(L·d) and 98 95 mmol/(L·d). The performance of Anammox reactor was efficient and stable.
基金Supported by the National Natural Science Foundation of China (No.20122203).
文摘This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L^-1(Na^+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the optimum sodium ion concentration [1000-2000mg·L^-1(Na^+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6-413.1mg·L^-1.h^-1, 28.04-28.97ml·g^-1, 7.52-7.83ml·g^-1.h^-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g^-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.
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.
基金Supported by the National Natural Science Foundation of China (No.20122203).
文摘This work evaluated the effects of sodium ion concentration, ranging from 0 to 16000mg·L-1(Na+), on the conversion of sucrose to hydrogen by a high-activity anaerobic hydrogen-producing granular sludge. At the opti- mum sodium ion concentration [1000—2000mg·L-1(Na+)] for hydrogen production at 37℃, the maximum sucrose degradation rate, the specific hydrogen production yield and the specific hydrogen production rate were 393.6— 413.1mg·L-1·h-1, 28.04—28.97ml·g-1, 7.52—7.83ml·g-1·h-1, respectively. The specific production yields of propionate, butyrate and valerate decreased with increasing sodium ion concentration, whereas the specific acetate production yield increased, meanwhile the specific production yields of ethanol and caproate were less than 55.3 and 12.6mg·g-1, respectively. The hybrid fermentation composition gradually developed from acetate, propionate and butyrate to acetate with the increase in sodium ion concentration.
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Acknowledgements This study was supported by the National Natural Science Foundation of China (Grant Nos. 50978146 and 51278271) and by the Environmental Scientific Research in the Public Interest (No. 201009017) from the Ministry of Environmental Protection of China.
文摘Bed expansion serves an important function in the design and operation of an upflow anaerobic reactor. An analysis of the flow pattern of expanded granular sludge bed (EGSB) reactors shows that most EGSB reactors do not behave as expanded bed reactors, as is widely perceived. Rather, these reactors behave as fluidized bed reactors based on the classic chemical reactor theory. In this paper, four bed expansion modes, divided as static bed, expanded bed, suspended bed, and fluidized bed, for bioreactors are proposed. A high-rate anaerobic suspended granular sludge bed (SGSB) reactor was then developed. The SGSB reactor is an upflow anaerobic reactor, and its expansion degree can be easily controlled within a range to maintain the suspended status of the sludge bed by controlling upfiow velocity. The results of the full-scale reactor confirmed that the use of SGSB reactors is advantageous. The full-scale SGSB reactor runs stably and achieves high COD removal efficiency (about 90%) at high loading rates (average 40 kg-COD·m^-3·d^-1, maximum to 52 kg·COD·m^-3 ·d^-1) based on the SGSB theory, and its expansion degree is between 22% and 37%.
基金Supported by Key Project of the Tenth Five-Year Plan of the Ministry of Science and Technology of China (02-2-2)
文摘An expanded granular sludge bed (EGSB) reactor was adopted to study the influence factors and rule of enhancing granular sludge concentration and performance. The experiment was performed at 33 ℃, pH 6.0-8.0 with continuous flow by adding proper quantity of nutritional trace elements. The results show that SLR was the key of steady operation of EGSB reactor. The increment of the granular sludge was influenced by volume loading rate (VLR), liquid up-flow velocity and sludge loading rate (SLR). Concentration of granular sludge increased rapidly when liquid up-flow velocity was over 0.94 m · h^-1 with SLR being at 1.0-2.0 d ^-1. With the propriety parameters: liquid up-flow velocity 2.52 m · h^-1, SLR 1.0-2.2 d^-1 and VLR 8.2-13.1 kg · m ^3 · d^-1, 23 days' continuous operation resulted in an increment by over 80% of granular sludge concentration in the EGSB reactor, plus good granular sludge property.
基金Sponsored by the National Natural Science Foundation of China(Grant No.20876117)National Key Technologies Research & Development Program(Grant No.2006BAJ08B10,2006BAJ04A07,2008BAJ08B21)
文摘A novel modified expanded granular sludge bed(EGSBm) reactor was developed for anaerobic treatment of municipal sewage with mixed liquid recirculation instead of effluent recirculation commonly adopted by a conventional EGSB(EGSBc) reactor.Performances of these two reactors were compared in treating municipal sewage at ambient temperatures ranging from 8 to 26 ℃.At an upflow liquid velocity(Vup) of 10.3 m/h,the mean concentrations of filtrated COD(CODfilt) and COD of the EGSBm effluent were determined to be 59.4 and 95.9 mg/L,respectively,which were significantly lower than those of the EGSBc effluent operated under identical experimental conditions.When the organic loading rate was suddenly increased from 1.2 to 7.2 kg COD/(m3·d),the EGSBm regained the removal efficiency of previous operation phase in 10 d.Hydrodynamic characteristics of the reactors were compared using the residence time distribution(RTD) model.It was found that the treatment efficiency of EGSBm kept increasing as the Vup increased.The polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis(PCR-DGGE) technique was used to analyze the microbial diversity in EGSBm.Fingerprinting pattern indicated that some species in the inoculating sludge were still reserved in the granular sludge of EGSBm,moreover,several new species occurred.
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.
基金supported by the National Natural Science Foundation of China (Nos. 51178215 and 51378251)the Jiangsu Nature Science Fund (No. BK2011032)+2 种基金Open Science Foundation of Jiangsu (No. 50808121)the National Science and Technology Major Project for Water Pollution Control and Treatment (No. 2012ZX07301-005)the 2012 Scientific Research Open Found of Jiangsu Key Laboratory of Environmental Engineering
文摘A two-phase anaerobic reactor fed with glucose substrate(3 g chemical oxygen demand(COD)/L) was used to investigate the effects of toxic metals on the degradation of organics and the soluble microbial product(SMP) formation. Low concentrations of Ni(II)(5 and10 mg/L) promoted the acid phase, whereas high concentrations(15, 20, and 25 mg/L)exhibited an inhibitory effect on, but did not alter the fermentative method, which mainly involved the fermentation of propionic acid. The methanogenic microorganism exhibited a strong capability adapting constantly increased Ni(II) levels. The acid phase was an accumulation stage of SMP. In the absence of Ni(II), the high-molecular-weight material in the effluent SMP mainly contained polysaccharide, tryptophan, and casein. Methanogens metabolized most of the polysaccharide, the whole tryptophan content, and part of the casein, leading to the presence of humic acid and protein in effluent. After Ni(II) dosage, the protein and polysaccharide of the acid phase increased, and tryptophan changed, while casein remained stable. More protein than polysaccharide was produced, suggesting the prominent function of protein when addressing the negative effect of toxic metals. The analysis of DNA confirmed the change of bacterial activity.
文摘The stability of performance of anaerobic ammonium oxidation (ANAMMOX) reactors was studied and the indices of performance stability were compared.The results showed that under different types of shock load, the reactors with different configurations displayed different stability.The biofilm reactor stood first in stability towards substrate shock load, followed by anaerobic sequencing batch reactor (SBR) and the granular sludge bed.And the biofilm reactor took the first place towards hydraulic shock load, followed by the granular sludge bed and SBR.The three ANAMMOX reactors were more tolerant to hydraulic shock load than to substrate shock load.When different kinds of stability assessment indices(i.e., sensitivity ratio, mean variance ratio and derivative regression function) were used, inconsistent assessment conclusions were reached.It was suggested that the mean deviation ratio and derivative regression function were more effective and universal.
文摘针对A^2/O+移动床生物膜反应器(A^2/O+MBBR)双污泥系统,以低碳氮比(C/N)生活污水为处理对象,考察启动过程的污泥特性和反硝化除磷特性,基于脱氮除磷的代谢机理建立系统的快速启动策略。研究结果表明:启动过程历时21 d完成,污泥结构稳定且具有较好的污泥沉降性和生物活性;平均重量污泥浓度从1 189 mg/L增加到1 760 mg/L,SVI值在95 m L/g MLSS以下,反硝化聚磷菌(DNPAOs)占聚磷菌(PAOs)的百分比从接种污泥时的10.87%增加到25.46%。启动过程,COD的去除效果基本稳定,A^2/O反应器可实现碳源的高效利用;硝化过程为反硝化除磷提供电子受体,TN的高效去除需要建立在NH+4-N氧化完全的基础上;PO_4^(3-)-P的去除特性与NO_3^--N的变化密切相关,除了缺氧区的同步脱氮除磷,好氧吸磷对稳定PO_4^(3-)-P出水浓度发挥着重要作用。在平均进水碳氮比为3.44的运行条件下,A^2/O+MBBR系统可实现有机物、氮、磷等污染物的同步高效去除,稳定运行阶段出水COD、NH_4^+-N、TN和PO_4^(3-)-P浓度分别为38.5、1.15、14.2、0.15 mg/L,COD、TN和PO_4^(3-)-P去除率分别为82.23%,74.72%和96.80%。DO、pH和ORP等实时控制参数的变化规律与脱氮除磷存在定量关系,稳定运行阶段厌氧区ORP为-398^-336 m V,反硝化过程pH值增幅0.55,ORP增加到-300^-175 m V,硝化过程pH值降低0.37。ORP、pH值可以直观地反映反硝化过程,pH值能够灵敏地反映硝化进程,实时控制参数的联合调控有利于促进系统的快速启动和稳定运行。