Considering that contaminated raw water mostly contains high Ammonia-N and a majority of water treatment plants use prechlorination process in China, efficiency of chloramines as a coagulant aid in enhancing coagulati...Considering that contaminated raw water mostly contains high Ammonia-N and a majority of water treatment plants use prechlorination process in China, efficiency of chloramines as a coagulant aid in enhancing coagulation was investigated by Jar stirring and pilot-scale tests, using Yellow River water containing high concentration of natural organic matters （NOM） and bromide in winter. The jar tests results showed that, compared with no preoxidation, preformed chloramine apparently decreased the turbidity of settled and filtered water with low dosage （2.0 rag/L）, and the aid-coagulation efficiency was further enhanced with the increase of chlorine （Cl2） to Ammonia-N （N） ratio. Pilot-scale studies indicated that, in comparison to the case without preoxidation, the turbidity removal efficiency of flotation and filtration effluent water was significantly improved, the particle counts of filtered water were decreased 63.4%, the average rate of filter head loss was reduced 18.2%, and filter run time was prolonged 15.7%. Therefore, chloramine preoxidation may substantially enhance the particle separation efficiency.展开更多
In order to improve the source water quality of drinking water and mitigate the load of drinking water treatment plant, a pilot test was conducted with integrated horizontal flow constructed wetlands to pretreat the w...In order to improve the source water quality of drinking water and mitigate the load of drinking water treatment plant, a pilot test was conducted with integrated horizontal flow constructed wetlands to pretreat the water supply in the reservoirs of Yellow River. Resuhs show that under the hydraulic loading rate of 4 m^3/（ m^2 · d）, the average removal rates of chemical oxygen demand （COD）, total nitrogen （TN）, ammonium nitrogen （ NH4 ^＋ - N）, nitrate nitrogen （ NO3 ^- - N）, nitrite - nitrogen （ NO2^ - - N） and total phosphorus （TP） in the horizontal flow constructed wetlands are 49. 68% , 53.01%, 48.48%, 53.61% , 62. 57% and 49. 56%, re- spectively. The study on purifying mechanism of the constructed wetlands indicates that the disposal of contamination by subsurface wetlands is the combined actions of physical chemistry, plants and microorganism.展开更多
In order to investigate the feasibility of pretreating the micro-polluted Yellow River raw water by constructed wetland, an experiment was conducted using a surface flow constructed wetland with composite plant bed. T...In order to investigate the feasibility of pretreating the micro-polluted Yellow River raw water by constructed wetland, an experiment was conducted using a surface flow constructed wetland with composite plant bed. The contamination removal efficiency and their trends in the wetland treatment system were studied under different hydraulic loading rates(HLR). The contamination removal efficiencies were compared according to the seasonal change under optimum HLR. The result shows that in the same season, under different hydraulic loadings ranging from 2 to 6 m3/(m2·d) at the same period, the best HLR is 4 m3/(m2·d) in the experimental system. The average removal rates of COD, TN, ammoniacal nitrogen(NH4+-N), and TP in the constructed wetland are 38.37%, 45.97%, 39.86% and 41.69%, respectively. According to China Standard for Surface Water Resources (GB3838-2002), mean effluent of COD, TN, NH4+-N and TP can nearly reach Grade Ⅲ, GradeⅤ, GradeⅠand GradeⅠ, respectively. Furthermore, treatment efficiency of the system in summer is obvious higher than that in other seasons. The expenditure of constructing the constructed wetland with the average treating capacity of 176 m3/d and lifetime of 20 years is 17075.00 RMB. The average disposal cost is summed up to 0.17 RMB/m3, which shows that the pretreatment of the micro-polluted Yellow River raw water by constructed wetland is feasible.展开更多
基金Project supported by the Hi-Tech Research and Development Pro- gram (863) of China (No. 2002AA601140)the Natural Science Foundation of Heilongjiang Province (No. E200510), China
文摘Considering that contaminated raw water mostly contains high Ammonia-N and a majority of water treatment plants use prechlorination process in China, efficiency of chloramines as a coagulant aid in enhancing coagulation was investigated by Jar stirring and pilot-scale tests, using Yellow River water containing high concentration of natural organic matters （NOM） and bromide in winter. The jar tests results showed that, compared with no preoxidation, preformed chloramine apparently decreased the turbidity of settled and filtered water with low dosage （2.0 rag/L）, and the aid-coagulation efficiency was further enhanced with the increase of chlorine （Cl2） to Ammonia-N （N） ratio. Pilot-scale studies indicated that, in comparison to the case without preoxidation, the turbidity removal efficiency of flotation and filtration effluent water was significantly improved, the particle counts of filtered water were decreased 63.4%, the average rate of filter head loss was reduced 18.2%, and filter run time was prolonged 15.7%. Therefore, chloramine preoxidation may substantially enhance the particle separation efficiency.
基金Sponsored by the National High Technology Research and Development Program (863) of China (Grant No.2006AA06Z303)the National Natural Sci-ence Foundation of China(Grant No.40671004)the Program for Young Academic Backbone of Harbin Normal University(Grant No.KGB200821)
文摘In order to improve the source water quality of drinking water and mitigate the load of drinking water treatment plant, a pilot test was conducted with integrated horizontal flow constructed wetlands to pretreat the water supply in the reservoirs of Yellow River. Resuhs show that under the hydraulic loading rate of 4 m^3/（ m^2 · d）, the average removal rates of chemical oxygen demand （COD）, total nitrogen （TN）, ammonium nitrogen （ NH4 ^＋ - N）, nitrate nitrogen （ NO3 ^- - N）, nitrite - nitrogen （ NO2^ - - N） and total phosphorus （TP） in the horizontal flow constructed wetlands are 49. 68% , 53.01%, 48.48%, 53.61% , 62. 57% and 49. 56%, re- spectively. The study on purifying mechanism of the constructed wetlands indicates that the disposal of contamination by subsurface wetlands is the combined actions of physical chemistry, plants and microorganism.
基金the National High Technology Research and Development Program of China(863 Program)(Grant No.2006AA06Z303).
文摘In order to investigate the feasibility of pretreating the micro-polluted Yellow River raw water by constructed wetland, an experiment was conducted using a surface flow constructed wetland with composite plant bed. The contamination removal efficiency and their trends in the wetland treatment system were studied under different hydraulic loading rates(HLR). The contamination removal efficiencies were compared according to the seasonal change under optimum HLR. The result shows that in the same season, under different hydraulic loadings ranging from 2 to 6 m3/(m2·d) at the same period, the best HLR is 4 m3/(m2·d) in the experimental system. The average removal rates of COD, TN, ammoniacal nitrogen(NH4+-N), and TP in the constructed wetland are 38.37%, 45.97%, 39.86% and 41.69%, respectively. According to China Standard for Surface Water Resources (GB3838-2002), mean effluent of COD, TN, NH4+-N and TP can nearly reach Grade Ⅲ, GradeⅤ, GradeⅠand GradeⅠ, respectively. Furthermore, treatment efficiency of the system in summer is obvious higher than that in other seasons. The expenditure of constructing the constructed wetland with the average treating capacity of 176 m3/d and lifetime of 20 years is 17075.00 RMB. The average disposal cost is summed up to 0.17 RMB/m3, which shows that the pretreatment of the micro-polluted Yellow River raw water by constructed wetland is feasible.
