河北应急水源的预臭氧化工艺研究

Study on pre-ozonation effect of Hebei temporary raw water

南水北调的应急工程是从河北四水库调水进京,四水库水源水质与密云水库水质相差较大。为了保证河北水进京后水厂工艺运行的稳定性,根据水厂现行工艺(混凝—沉淀—煤砂过滤—活性炭过滤)增加预臭氧在河北黄壁庄水库进行适应性研究。试验结果表明:在投加臭氧1.5～2.6mg/L后炭出水基本无味;试验条件为:臭氧浓度0.4mg/L,接触时间8min时,预臭氧能够将剑水蚤杀死去除;预臭氧后系统对有机物去除效果较好,且沉后藻类去除率达到80%以上,煤滤池出水藻类低于2万个/L;中试系统煤滤池出水和炭滤池出水溴酸盐浓度均小于5μg/L,因此臭氧氧化后不存在溴酸盐副产物超标的风险。同时,建议在河北水进京前测定水中MIB浓度,适时调整臭氧投加量,在有必要的情况下考虑增加粉末活性炭预吸附。

The emergency measure for the South-to-North Water Diversion project is to transmit water from Hebei Sishui reservoir to Beijing, and the water quality is different between Miyun reservoir and Sishui reservoir. To ensure the stability of water treatment, jar test and pilot test were carried out in Huangbizhuang reservoir of Hebei province, according to the present water process （coagulation--sedimentation--coal and sand filtration--GAC filtration） and the addition of the pre-ozonation. The results showed that. the smell level of effluent （after GAC） was zero when pre-ozonation dosage was 1.5-2.6 mg/L; pre-ozonation can kill and remove Cyclops, and residual ozone concentration was 0.4 mg/L, contacting time was 8 min; the removing efficiency of organ substance could be enhanced by pre-ozonation, and alga removing efficiency of sedimentation can achieve 80%, alga in coal-sand effluent was less than 2 × 10^4cell/L; bromate of filer and GAC effluent was less than 5 μg/L, which means that by-product of bromate was in control. Meanwhile, it was recommended to detect MIB concentration of Hebei temporary raw water before its arrival in Beijing, and adjust pre-ozonation dosage according to current situation, and increase pre-adsorption of PAC if necessary.