臭氧活性炭-后置砂滤工艺对水中农药的控制效能

选择我国饮用水水质标准中有相关规定,以及部分用量较大或虽被禁用但仍有残留的农药共25种,对黄浦江水源水以及采用臭氧活性炭-后置砂滤工艺的某水厂工艺段出水中的浓度分布进行了调查,评估了砂滤后置工艺条件下相应农药的实际处理效果。结果表明:原水中有包括莠去津、乐果、六氯苯、敌敌畏、乙草胺、丁草胺、仲丁威和p,p'-DDT的8种农药检出,且总浓度较高达到760 ng/L,其中莠去津和乙草胺含量较高,最高浓度分别达到531 ng/L和277 ng/L;从季节性分布来看,春季总农药浓度最高达760 ng/L,秋季最低为175 ng/L。从工艺去除效果来看,臭氧活性炭砂滤后置工艺对农药的总体去除率为62%~78%,与冬春季相比,夏秋季节的农药的去除率提高约10%左右,这可能与高温期微生物活性较高有关。值得关注的是,砂滤后置工艺与同期常规臭氧活性炭工艺相比农药的总去除率要低10%左右,应结合总体出水水质情况对其进一步评估。

Pesticides removal evaluation for O3/BAC with post filtration process in drinking water

In this study, 25 pesticide variations were investigated throughout the ozone (O3)-biological activated carbon (BAC) with post-filtration process in one drinking water plant using the Huangpu River as the source water. As indicated, among the pesticides, eight species were detected in the raw water, including atrazine, dimethoate, hexachlorobenzene, dichlorvos, acetochlor, butachlor, fenobucarb, and p,p'-DDT. The highest concentration of 760 ng/L was detected in the spring, among which, atrazine and acetochlor had much higher concentrations, 531 ng/L and 277 ng/L, respectively. A removal rate of 62% to 78% was obtained for the O3-BAC with post-filtration process in this plant. A removal efficiency of 10% higher than the winter season was obtained during the summer and autumn. Much higher temperatures may be the main reason, as they induce a much more active microbial metabolism process in the BAC. However, compared to the conventional O3-BAC process, the total removal efficiency was lower by about 10%. The feasibility of this advanced process should be further evaluated combing with the whole water quality control effects in drinking water.