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
水厂排泥水处理过程中会产生较大量的污泥脱水液。为避免南水北调引江水资源的浪费,同时积极推进水厂的“零排放”建设目标,面向以引江水为水源的超滤处理工艺,评价了将污泥脱水液回流至原水池进行稀释回用的可行性。考察了不同污泥脱水...水厂排泥水处理过程中会产生较大量的污泥脱水液。为避免南水北调引江水资源的浪费,同时积极推进水厂的“零排放”建设目标,面向以引江水为水源的超滤处理工艺,评价了将污泥脱水液回流至原水池进行稀释回用的可行性。考察了不同污泥脱水液/引江原水混合比例下超滤系统的运行特性,发现当污泥脱水液适当稀释后,其对超滤净水效果和膜污染的影响急剧降低,当稀释比例达到1∶800时,出水水质与跨膜压增长曲线已接近引江原水直接超滤的情况。试验中引江原水的跨膜压增长速率为19.7 k Pa/d,而污泥脱水液原液则达到25.8 k Pa/d。当两者以1∶800比例稀释后,跨膜压增长速率下降为21.3 k Pa/d,接近于引江原水。膜表面微观表征结果显示随着稀释比例的提高,滤饼层厚度、溶解性有机物、特征官能团红外峰强、污染元素相对质量分数均显著降低,逐渐下降到与原水直接超滤相近的水平。引江原水组的超滤膜滤饼层厚度为1.77μm,而污泥脱水液原液组的滤饼层厚度为4.00μm,污染程度较重。两者按1∶800比例稀释后的滤饼层厚度降低至1.82μm,污染程度显著降低。研究结果可为南水北调受水城市超滤水厂的“零排放”建设提供参考。但值得注意的是,污泥脱水液的合理处置与利用问题目前仍处于起步和探索阶段,未来仍需从水质生物安全性和化学安全性的角度加以系统评估。同时可考虑氧化、吸附、微滤分离等预处理手段,以提高污泥脱水液回用过程的安全性。展开更多
Bormate （BrO3^-） is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the format...Bormate （BrO3^-） is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet （UV）/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards （10 μg/L）. UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%-32% of Br^- was oxidized to BrO3^-. And the formation of bromate exhibited three stages： rapid stage, slow stage and plateau. Under the experimental conditions （pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L）, low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.展开更多
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.
文摘水厂排泥水处理过程中会产生较大量的污泥脱水液。为避免南水北调引江水资源的浪费,同时积极推进水厂的“零排放”建设目标,面向以引江水为水源的超滤处理工艺,评价了将污泥脱水液回流至原水池进行稀释回用的可行性。考察了不同污泥脱水液/引江原水混合比例下超滤系统的运行特性,发现当污泥脱水液适当稀释后,其对超滤净水效果和膜污染的影响急剧降低,当稀释比例达到1∶800时,出水水质与跨膜压增长曲线已接近引江原水直接超滤的情况。试验中引江原水的跨膜压增长速率为19.7 k Pa/d,而污泥脱水液原液则达到25.8 k Pa/d。当两者以1∶800比例稀释后,跨膜压增长速率下降为21.3 k Pa/d,接近于引江原水。膜表面微观表征结果显示随着稀释比例的提高,滤饼层厚度、溶解性有机物、特征官能团红外峰强、污染元素相对质量分数均显著降低,逐渐下降到与原水直接超滤相近的水平。引江原水组的超滤膜滤饼层厚度为1.77μm,而污泥脱水液原液组的滤饼层厚度为4.00μm,污染程度较重。两者按1∶800比例稀释后的滤饼层厚度降低至1.82μm,污染程度显著降低。研究结果可为南水北调受水城市超滤水厂的“零排放”建设提供参考。但值得注意的是,污泥脱水液的合理处置与利用问题目前仍处于起步和探索阶段,未来仍需从水质生物安全性和化学安全性的角度加以系统评估。同时可考虑氧化、吸附、微滤分离等预处理手段,以提高污泥脱水液回用过程的安全性。
文摘Bormate （BrO3^-） is a carcinogenic chemical produced in ozonation or chlorination of bromide-containing water. Although its formation in seawater with or without sunlight has been previously investigated, the formation of bromate in dilute solutions, particularly raw water for water treatment plant, is unknown. In this article, the results of bench scale tests to measure the formation rates of bromate formation in dilute solutions, including de-ionized water and raw water from Yangtze River, were presented in dark chlorination and ultraviolet （UV）/chlorination processes. And the effects of initial pH, initial concentration of NaOCl, and UV light intensity on bromate formation in UV/chlorination of the diluted solutions were investigated. Detectable bromate was formed in dark chlorination of the two water samples with a relatively slow production rate. Under routine disinfecting conditions, the amount of formed bromate is not likely to exceed the national standards （10 μg/L）. UV irradiation enhanced the decay of free chlorine, and, simultaneously, 6.6%-32% of Br^- was oxidized to BrO3^-. And the formation of bromate exhibited three stages： rapid stage, slow stage and plateau. Under the experimental conditions （pH = 4.41-11.07, CCl2= 1.23-4.50 mg/L）, low pH and high chlorine concentration favored the generation of bromate. High light intensity promoted the production rate of bromate, but decreased its total generation amount due to acceleration of chlorine decomposition.
