With rural population expansion and improvement of the socio-economic standard of living, treatment of rural domestic wastewater has rapidly become a major aspect of environmental concern. Selection of a suitable meth...With rural population expansion and improvement of the socio-economic standard of living, treatment of rural domestic wastewater has rapidly become a major aspect of environmental concern. Selection of a suitable method for treatment of rural domestic wastewater depends on its efficiency, simplicity, and cost-effectiveness. This study investigated the effects of hydraulic retention time （HRT）, temperature, and effluent recycling on the treatment efficiency of an anaerobic filter （AF） reactor. The first round of experimental operations was run for three months with HRTs of one, two, and three days, temperatures of 18℃, 21℃, and 24℃, and no effluent recycling. The second round of experimental operations was conducted for another three months with HRTs of three and four days; temperatures of 30.67℃, 30.57℃, and 26.91 ℃ ; and three effluent recycling ratios of 1：1, 1：2, and 2：1. The first round of operations showed removal rates of 32% to 44% for COD, 30% to 35% for TN, 32% to 36% for NH4-N, 19% to 23% for NO3-N, and 12% to 22% for TE In the second round of operations, the removal rates varied from 75% to 81% for COD, 35% to 41% for TN, 31% to 39% for NH4-N, 30% to 34% for NO3-N, and 41% to 48% for TP. The average gas production rates were 6.72 L/d and 7.26 L/d for the first and second rounds of operations, respectively. The gas production rate increased in the second round of operations as a result of applied effluent recycling. The best removal efficiency was obtained for an optimum HRT of three days, a temperature of 30℃, and an effluent recycling ratio of 2：1. The results show that the removal efficiency of the AF reactor was affected by HRT, temperature, and effluent recycling.展开更多
This paper describes the feasibility of fresh leachate treatment by an upflow blanket filter(UBF).Through dilution and partial effluent recycling,the organic loading rates increased from 0.51 to 14.56 kg COD/(m^(3)...This paper describes the feasibility of fresh leachate treatment by an upflow blanket filter(UBF).Through dilution and partial effluent recycling,the organic loading rates increased from 0.51 to 14.56 kg COD/(m^(3)·d),meanwhile the corresponding hydraulic retention time decreased from 9.0 to 3.6 d.The reactor was able to achieve steady-state within 80 d.Based on the distribution of COD fluxes in the process,it was concluded that anabolism was the main pathway of COD removal in the initial phase(1–33 d),accounting for 57%–85%of total COD removed.As the anaerobic consortium of bacteria reached steady-state(after 70–86 d),the majority of COD removed was transformed into methane,because the specific methane yield was close to the theoretical value(0.36 L CH4/(g CODdeg)).展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51078074)the Key Project of the Chinese Ministry of Education(Grant No.308010)
文摘With rural population expansion and improvement of the socio-economic standard of living, treatment of rural domestic wastewater has rapidly become a major aspect of environmental concern. Selection of a suitable method for treatment of rural domestic wastewater depends on its efficiency, simplicity, and cost-effectiveness. This study investigated the effects of hydraulic retention time （HRT）, temperature, and effluent recycling on the treatment efficiency of an anaerobic filter （AF） reactor. The first round of experimental operations was run for three months with HRTs of one, two, and three days, temperatures of 18℃, 21℃, and 24℃, and no effluent recycling. The second round of experimental operations was conducted for another three months with HRTs of three and four days; temperatures of 30.67℃, 30.57℃, and 26.91 ℃ ; and three effluent recycling ratios of 1：1, 1：2, and 2：1. The first round of operations showed removal rates of 32% to 44% for COD, 30% to 35% for TN, 32% to 36% for NH4-N, 19% to 23% for NO3-N, and 12% to 22% for TE In the second round of operations, the removal rates varied from 75% to 81% for COD, 35% to 41% for TN, 31% to 39% for NH4-N, 30% to 34% for NO3-N, and 41% to 48% for TP. The average gas production rates were 6.72 L/d and 7.26 L/d for the first and second rounds of operations, respectively. The gas production rate increased in the second round of operations as a result of applied effluent recycling. The best removal efficiency was obtained for an optimum HRT of three days, a temperature of 30℃, and an effluent recycling ratio of 2：1. The results show that the removal efficiency of the AF reactor was affected by HRT, temperature, and effluent recycling.
基金the National High-Tech Research and Development Program(863 Program)of China(Grant No.2008AA062101)the Key Project of Chinese Ministry of Education(No.107122)。
文摘This paper describes the feasibility of fresh leachate treatment by an upflow blanket filter(UBF).Through dilution and partial effluent recycling,the organic loading rates increased from 0.51 to 14.56 kg COD/(m^(3)·d),meanwhile the corresponding hydraulic retention time decreased from 9.0 to 3.6 d.The reactor was able to achieve steady-state within 80 d.Based on the distribution of COD fluxes in the process,it was concluded that anabolism was the main pathway of COD removal in the initial phase(1–33 d),accounting for 57%–85%of total COD removed.As the anaerobic consortium of bacteria reached steady-state(after 70–86 d),the majority of COD removed was transformed into methane,because the specific methane yield was close to the theoretical value(0.36 L CH4/(g CODdeg)).
