河北南部南水北调原水强化混凝效果及残余铝含量

采用浓度分别为15、20、25 mg/L的聚合氯化铝(PAC)联合硅藻土强化混凝处理河北南部南水北调水源水,研究了对浊度、叶绿素a、CODMn和UV254的去除效果以及残余铝含量;通过改变硅藻土与PAC的投加时间和顺序,确定最佳混凝条件。结果表明:单独投加PAC时,其最佳投加量为25 mg/L,对浊度、叶绿素a、CODMn、UV254的去除率分别为92%、86.7%、34%、30%;同时投加PAC和吸附剂硅藻土时,对叶绿素a的去除率有大幅度提高,强化混凝处理南水北调水源水的最佳药剂组合为15 mg/L的PAC和20 mg/L硅藻土,对浊度和叶绿素a的去除率均为93%,对CODMn及UV254的去除率分别达到41.4%和37.9%,残余铝含量降至0.179 mg/L;先投加PAC慢速搅拌10 min后再投加硅藻土进行混凝对各指标的去除率最高,对浊度、叶绿素a、CODMn及UV254的去除率分别达到94.4%、93%、41.8%、38.4%,残余铝含量低至0.176 mg/L。

Enhanced Coagulation and Residual Aluminum Content of Source Water from South-to-North Water Diversion Project in Southern Hebei Province

The removal of turbidity,chlorophyll a,CODMn,and UV254 by polyaluminium chloride (PAC) and diatomite was studied,using source water from the South-to-North Water Diversion Project in southern Hebei Province. The residual aluminum content was analyzed as well. PAC concentrations of 15 mg/L,20 mg/L,and 25 mg/L were tested. The dosing time and order of diatomite and PAC were tested to achieve the best coagulation condition. The results showed that the optimal amount of PAC was 25 mg/L where used separately,and the removal rates of turbidity,chlorophyll a,CODMn,and UV254 were 92%,86. 7%,34%,and 30%,respectively. When PAC and diatomite was added together,the removal rate of chlorophyll a was substantially increased. The optimal dosages were 15 mg/L PAC and 20 mg/L diatomite,and the removal rates of turbidity,chlorophyll a,CODMn,and UV254 reached 93%,93%,41. 4%,and 37. 9%,respectively. The residual aluminum content was reduced to 0. 179 mg/L.The removal rate reached the highest level when diatomite was added after PAC was added and slowly stirred for 10 min,the removal rates of turbidity,chlorophyll a,CODMn,and UV254 were 94. 4%,93%,41. 8%,and 38. 4%,respectively. The residual aluminum content was as low as 0. 176 mg/L.