The combination method of intermittent influent and vertical flow wetlands （VFW） was used in the test to treat the domestic wastewater. Four artificial wetlands including Typha latifolia wetland,Phragmites australis...The combination method of intermittent influent and vertical flow wetlands （VFW） was used in the test to treat the domestic wastewater. Four artificial wetlands including Typha latifolia wetland,Phragmites australis （P.H.） wetland,polyculture wetlands （Typha latifolia and Phragmites australis） and non-vegetation wetland were established in the test. The effects of hydraulic retention time （HRT） and plant species on pollutants removal efficiencies were studied. The results showed that when HRT=7,the treatment efficiencies of wetlands with plants for the removal of TN and NH＋4-N were up to 99.65% and 99.58%,respectively. For the control wetland,TN removal efficiency was up to 87.9% when HRT were 6 days,and NH＋4-N removal efficiency was up to 91.8% when HRT were 5 days. TP removal efficiencies of four wetlands were higher than 93% when HRT was 6 days. Through the studies on different plants,it was found that vegetation wetlands had better nitrogen removal efficiency than non-vegetation wetland. The treatment efficacy of Phragmites australis wetland and polyculture wetland was better than Typha latifolia wetland.展开更多
A novel modified pilot scale anaerobic oxidation ditch with additional internal anoxic zones was operated experimentally, aiming to study the improvement of biological nitrogen and phosphorus removal and the effect of...A novel modified pilot scale anaerobic oxidation ditch with additional internal anoxic zones was operated experimentally, aiming to study the improvement of biological nitrogen and phosphorus removal and the effect of enhanced denitrifying phosphorus removal in the process. Under all experimental conditions, the anaero- bic-oxidation ditch with additional internal anoxic zones and an internal recycle ratio of 200% had the highest nutrient removal efficiency. The effluent NH4 -N, total nitrogen （TN）, PO3 -P and total phosphorus （TP） contents were 1.2 mg.L-1, 13 mg.L 1, 0.3 mg.L -1 and 0.4 mg.L-1, respectively, all met the discharge standards in China. The TN and TP removal efficiencies were remarkably improved from 37% and 50% to 65% and 88% with the presence of additional internal anoxic zones and internal recycle ratio of 200%. The results indicated that additional internal anoxic zones can optimize the utilization of available carbon source from the anaerobic outflow for denitrification. It was also found that phosphorus removal via the denitrification process was stimulated in the additional internal anoxic zones, which was beneficial for biological nitrogen and phosphorus removal when treating wastewater with a limited carbon source. However, an excess internal recycle would cause nitrite to accumulate in the system. This seems to be harmful to biological phosphorus removal.展开更多
In order to investigate the competition for carbon source between denitrification and phosphorus release processes,simultaneous phosphorus release and denitrification in sludge operated in anoxic,aerobic mode are inve...In order to investigate the competition for carbon source between denitrification and phosphorus release processes,simultaneous phosphorus release and denitrification in sludge operated in anoxic,aerobic mode are investigated by varying the ratio of influent COD to nitrogenous compound concentration under anoxic condition using a lab-scale sequencing batch reactor（SBR）.The results show that the nitrate reduction rate is nearly independent of the ratio of influent COD to nitrate under anoxic condition.More NOx^--N in the influent leads to less PO4^3--P release during the feeding period.However, PO4^3--P release proceeds at a low rate simultaneously with denitrification even when the influent NOx^--N concentration is as large as 20 mg·L^-1and its rate is increased obviously when NOx^--N is denitrified to a concentration lower than 0.5 mg·L^-1.The variation of pH during anoxic period gives some information about the biochemical reactions of denitrification and PO4^3--P release.When more nitrate is present in the influent,more acetate uptake in feeding period is used for direct microorganism growth.展开更多
A novel full scale modified A2O （anoxic/anaerobic/aerobic/pre-anoxic）-membrane bioreactor （MBR） plant combined with the step feed strategy was operated to improve the biological nutrient removal （BNR） from low C...A novel full scale modified A2O （anoxic/anaerobic/aerobic/pre-anoxic）-membrane bioreactor （MBR） plant combined with the step feed strategy was operated to improve the biological nutrient removal （BNR） from low C/N ratio municipal wastewater in Southern China. Transformation of organic carbon, nitrogen and phosphorus, and membrane fouling were investigated. Experimental results for over four months demonstrated good efficiencies for chemical oxygen demand （COD） and NH4^＋-N removal, with average values higher than 84.5%and 98.1%, re-spectively. A relatively higher total nitrogen （TN） removal efficiency （52.1%） was also obtained at low C/N ratio of 3.82, contributed by the configuration modification （anoxic zone before anaerobic zone） and the step feed with a distribution ratio of 1：1. Addition of sodium acetate into the anoxic zone as the external carbon source, with a theoretical amount of 31.3 mg COD per liter in influent, enhanced denitrification and the TN removal efficiency in-creased to 74.9%. Moreover, the total phosphate （TP） removal efficiency increased by 18.0%. It is suggested that the external carbon source is needed to improve the BNR performance in treating low C/N ratio municipal waste-water in the modified A^2O-MBR process.展开更多
The aim of this work is to evaluate the feasibility of applying the technology of oxidation-reduction potential （ORP） control on the municipal wastewater treatment system for nitrogen and phosphorus removal. Meanwhi...The aim of this work is to evaluate the feasibility of applying the technology of oxidation-reduction potential （ORP） control on the municipal wastewater treatment system for nitrogen and phosphorus removal. Meanwhile the relation between the optimal ORP （ ORPopt ） and influent C/N ratio was evaluated, in which the influent chemical oxygen demand （ COD ） concentration was stabilized at （290 ± 10 ） mg/L, the influent total phosphorus （TP） concentration was stabilized at （7.0 ± 0.5 ） mg/L. The results indicated that： （1） the ORP in the second anoxic zone had effect on nitrogen and phosphorus removal capability, and the average percentages of phosphorus uptake in ANO2 zone （ ηa ） increased with increasing ORP, i. e. , increasing from 12. 0% at - 143 mV to 22.0%,30.0%,37.0%, and45.0% at -123, -111, -105 and -95 mV, respectively; （2） the ORPopt as function of influent C/N ratio could be calculated by the equation： y ffi 252. 73e〈 -x/3.39） _ 131.01 ; the maximum percentage of phosphorus uptake in ANO2 as function of the ORPopt could be calculated by the equation： y ffi -0.49e（x/15.58） ＋ 1. 51. The ORPopt was the important process control parameter that must be optimized for operation of enhanced biological phosphorus removal （ EBPR ） system. Moreover, ORP sensor is very simple, and the industrial applications of this strategy is practical.展开更多
The application of the Genetic Algorithm （GA） for the influent flow optimized distribution in the four stage pilot plant of Step-Feed Biological Nutrient Removal （BNR） System was discussed. Under decided process p...The application of the Genetic Algorithm （GA） for the influent flow optimized distribution in the four stage pilot plant of Step-Feed Biological Nutrient Removal （BNR） System was discussed. Under decided process parameter and influent water conditions, the objective function of optimization was designed to minimize the difference between estimated and required effluent concentrations at the four stage pilot plant of Step-Feed BNR System, the optimized parameter for influent distribution ratios of the four stages is 37.2%, 27.4%, 23.2% and 12.2% respectively. According to the optimizations results and raw wastewater pilot-scale experiment, the average removal efficiencies for pollutants are higher.展开更多
In order to enhance efficiency of the nitrogen and phosphorus removal of sewage treatment plant, Taking Wu Long kou sewage treatment plant project in Zhengzhou as an example, this article introduces the structure, the...In order to enhance efficiency of the nitrogen and phosphorus removal of sewage treatment plant, Taking Wu Long kou sewage treatment plant project in Zhengzhou as an example, this article introduces the structure, the working principle, the craft character, as well as the problems existed in the practical application of the improved oxidation ditch, and raises some corresponding processing countermeasures. Looked from the running situation of Wu Long kou sewage treatment plant, the improved oxidation ditch have certain advantages in city sewage treatment, such as high organic removing efficiency, good removing effect of nitrogen and phosphorus, low investing expenses and operating cost and so on. It is a craft that is worth promoting in urban sewage treatment.展开更多
基金Supported by National Natural Science Foundation of China(50908116 )211 Foundation of Nanjing Normal University(2009112XGQ0054)+1 种基金Jiang su High-funded Construction ProjectsMajor Project of Jiangsu Provincial Department of Education(2009105TSJ0165)~~
文摘The combination method of intermittent influent and vertical flow wetlands （VFW） was used in the test to treat the domestic wastewater. Four artificial wetlands including Typha latifolia wetland,Phragmites australis （P.H.） wetland,polyculture wetlands （Typha latifolia and Phragmites australis） and non-vegetation wetland were established in the test. The effects of hydraulic retention time （HRT） and plant species on pollutants removal efficiencies were studied. The results showed that when HRT=7,the treatment efficiencies of wetlands with plants for the removal of TN and NH＋4-N were up to 99.65% and 99.58%,respectively. For the control wetland,TN removal efficiency was up to 87.9% when HRT were 6 days,and NH＋4-N removal efficiency was up to 91.8% when HRT were 5 days. TP removal efficiencies of four wetlands were higher than 93% when HRT was 6 days. Through the studies on different plants,it was found that vegetation wetlands had better nitrogen removal efficiency than non-vegetation wetland. The treatment efficacy of Phragmites australis wetland and polyculture wetland was better than Typha latifolia wetland.
基金Supported by Major Science and Technology Program for Water Pollution Control and Treatment(2008ZX07316)
文摘A novel modified pilot scale anaerobic oxidation ditch with additional internal anoxic zones was operated experimentally, aiming to study the improvement of biological nitrogen and phosphorus removal and the effect of enhanced denitrifying phosphorus removal in the process. Under all experimental conditions, the anaero- bic-oxidation ditch with additional internal anoxic zones and an internal recycle ratio of 200% had the highest nutrient removal efficiency. The effluent NH4 -N, total nitrogen （TN）, PO3 -P and total phosphorus （TP） contents were 1.2 mg.L-1, 13 mg.L 1, 0.3 mg.L -1 and 0.4 mg.L-1, respectively, all met the discharge standards in China. The TN and TP removal efficiencies were remarkably improved from 37% and 50% to 65% and 88% with the presence of additional internal anoxic zones and internal recycle ratio of 200%. The results indicated that additional internal anoxic zones can optimize the utilization of available carbon source from the anaerobic outflow for denitrification. It was also found that phosphorus removal via the denitrification process was stimulated in the additional internal anoxic zones, which was beneficial for biological nitrogen and phosphorus removal when treating wastewater with a limited carbon source. However, an excess internal recycle would cause nitrite to accumulate in the system. This seems to be harmful to biological phosphorus removal.
基金Supported by the Scientific Innovation Platform of Beijing Municipal Education Commission(PXM2008_014204_050843)State Key Laboratory of Urban Water Resource and Environment(HIT)(QAK200802)Environment and Water Industry(EWI)Development Scheme of Singapore-The Process Control and Enhanced Biological Nutrient Removal of CSTR Proc-ess(EDB S07/1-53974082)
文摘In order to investigate the competition for carbon source between denitrification and phosphorus release processes,simultaneous phosphorus release and denitrification in sludge operated in anoxic,aerobic mode are investigated by varying the ratio of influent COD to nitrogenous compound concentration under anoxic condition using a lab-scale sequencing batch reactor（SBR）.The results show that the nitrate reduction rate is nearly independent of the ratio of influent COD to nitrate under anoxic condition.More NOx^--N in the influent leads to less PO4^3--P release during the feeding period.However, PO4^3--P release proceeds at a low rate simultaneously with denitrification even when the influent NOx^--N concentration is as large as 20 mg·L^-1and its rate is increased obviously when NOx^--N is denitrified to a concentration lower than 0.5 mg·L^-1.The variation of pH during anoxic period gives some information about the biochemical reactions of denitrification and PO4^3--P release.When more nitrate is present in the influent,more acetate uptake in feeding period is used for direct microorganism growth.
基金Supported by the National Water Pollution Control and Management(2008ZX07316-002)the University of Macao Research Committee(RG067/09-10S/SHJ/FST)
文摘A novel full scale modified A2O （anoxic/anaerobic/aerobic/pre-anoxic）-membrane bioreactor （MBR） plant combined with the step feed strategy was operated to improve the biological nutrient removal （BNR） from low C/N ratio municipal wastewater in Southern China. Transformation of organic carbon, nitrogen and phosphorus, and membrane fouling were investigated. Experimental results for over four months demonstrated good efficiencies for chemical oxygen demand （COD） and NH4^＋-N removal, with average values higher than 84.5%and 98.1%, re-spectively. A relatively higher total nitrogen （TN） removal efficiency （52.1%） was also obtained at low C/N ratio of 3.82, contributed by the configuration modification （anoxic zone before anaerobic zone） and the step feed with a distribution ratio of 1：1. Addition of sodium acetate into the anoxic zone as the external carbon source, with a theoretical amount of 31.3 mg COD per liter in influent, enhanced denitrification and the TN removal efficiency in-creased to 74.9%. Moreover, the total phosphate （TP） removal efficiency increased by 18.0%. It is suggested that the external carbon source is needed to improve the BNR performance in treating low C/N ratio municipal waste-water in the modified A^2O-MBR process.
基金National Natural Science Foundation of China(NSFC)(No.50978118)
文摘The aim of this work is to evaluate the feasibility of applying the technology of oxidation-reduction potential （ORP） control on the municipal wastewater treatment system for nitrogen and phosphorus removal. Meanwhile the relation between the optimal ORP （ ORPopt ） and influent C/N ratio was evaluated, in which the influent chemical oxygen demand （ COD ） concentration was stabilized at （290 ± 10 ） mg/L, the influent total phosphorus （TP） concentration was stabilized at （7.0 ± 0.5 ） mg/L. The results indicated that： （1） the ORP in the second anoxic zone had effect on nitrogen and phosphorus removal capability, and the average percentages of phosphorus uptake in ANO2 zone （ ηa ） increased with increasing ORP, i. e. , increasing from 12. 0% at - 143 mV to 22.0%,30.0%,37.0%, and45.0% at -123, -111, -105 and -95 mV, respectively; （2） the ORPopt as function of influent C/N ratio could be calculated by the equation： y ffi 252. 73e〈 -x/3.39） _ 131.01 ; the maximum percentage of phosphorus uptake in ANO2 as function of the ORPopt could be calculated by the equation： y ffi -0.49e（x/15.58） ＋ 1. 51. The ORPopt was the important process control parameter that must be optimized for operation of enhanced biological phosphorus removal （ EBPR ） system. Moreover, ORP sensor is very simple, and the industrial applications of this strategy is practical.
文摘The application of the Genetic Algorithm （GA） for the influent flow optimized distribution in the four stage pilot plant of Step-Feed Biological Nutrient Removal （BNR） System was discussed. Under decided process parameter and influent water conditions, the objective function of optimization was designed to minimize the difference between estimated and required effluent concentrations at the four stage pilot plant of Step-Feed BNR System, the optimized parameter for influent distribution ratios of the four stages is 37.2%, 27.4%, 23.2% and 12.2% respectively. According to the optimizations results and raw wastewater pilot-scale experiment, the average removal efficiencies for pollutants are higher.
文摘In order to enhance efficiency of the nitrogen and phosphorus removal of sewage treatment plant, Taking Wu Long kou sewage treatment plant project in Zhengzhou as an example, this article introduces the structure, the working principle, the craft character, as well as the problems existed in the practical application of the improved oxidation ditch, and raises some corresponding processing countermeasures. Looked from the running situation of Wu Long kou sewage treatment plant, the improved oxidation ditch have certain advantages in city sewage treatment, such as high organic removing efficiency, good removing effect of nitrogen and phosphorus, low investing expenses and operating cost and so on. It is a craft that is worth promoting in urban sewage treatment.
