微污染水库原水的消毒副产物控制

上海市南汇自来水厂从青草沙水库取水,原水加氯后在输送途中反应生成的消毒副产物(DBPs)使得原有处理技术和工艺难以达到上海市的新版地方标准DB31/T 1091—2018,为此,需要进行研究改进DBPs的控制方法和工艺。试验以水厂原水为研究对象,分析活性炭的吸附、多点加氯等工艺对消毒副产物生成的影响,同时研究了温度与消毒副产物产生的关系。研究发现,投加粉末活性炭15~20 mg/L后,三卤甲烷(THMs)的控制效果明显,即使加氯量达到3 mg/L,THMs也不超过0.15mg/L。多点加氯可以有效降低前期加氯造成的消毒副产物生成量,水温升高使得余氯量明显降低,从而影响消毒副产物的生成量。消毒后的水样中三氯甲烷浓度约为其他组分的一倍,控制三氯甲烷的生成是控制THMs的关键。本研究推荐采用添加粉末活性炭、控制水温夏天方法来削减南汇自来水厂出水中THMs的总量,研究也为自来水厂消毒副产物的控制提供了实操性的建议和技术依据。

Control of Disinfection By-Products in Micro-Polluted Raw Water of Reservoir

The raw water of Shanghai Nanhui Water Treatment Plant originate from Qingcaosha reservoir,which could form disinfection by-products(DBPs)during transportation.Therefore,the original treatment and process could be hard to reach the new local standard DB31/T 1091—2018,and need to be improved.The raw water of Shanghai Nanhui Water Treatment Plant was studied,the effects of the absorption of activated carbon and multi-point chlorination to DBPs was analyzed,and the relationship between temperature and DBPs was studied.Evident control of trihalomethanes(THMs)was found after adding 15~20 mg/L powder activated carbon,and THMs wouldn’t exceed 0.15 mg/L even when the addition of chloride was 3 mg/L.The multi-point chlorination could effectively decrease the formation of DBPs caused by former chloride addition.The chloride residue reduced obviously by the rise of temperatures and thus deducing the formation of DBPs.The concentration of CHCl3 was twice as much as other substances,and the reduction of CHCl3 forming was the key to control the THMs.In this study,addition of powder activated carbon and adjustment of temperature was recommended for reducing the THMs of Shanghai Nanhui Water Treatment Plant,and practical suggestions and technical proofs was also provided for controlling DBPs.