混凝沉淀法处理含铅矿坑涌水

实验采用常见的聚合氯化铝(PAC)、聚合硫酸铁(PFS)、聚丙烯酰胺(PAM)通过烧杯混凝实验进行除铅, 比较了3种絮凝剂对矿坑涌水中铅的去除效果;进而比较了3种絮凝剂分别组合之后对铅的去除效果, 筛选出既高效又经济的混凝剂组合, 并最终确定混凝剂组合为PFS和PAM。并且考察了投加顺序和pH值对组合混凝剂除铅效果的影响。结果表明:分别在最佳PAC、PFS投药条件下与PAM混用, 对含铅矿坑涌水的处理效果要比单独使用PAC、PFS任何一种絮凝剂效果好, PAM有利于提高PAC、PFS对铅的去除率。PFS与PAM组合除铅最佳工艺条件为:pH值为9.5, PFS投加量200mg/L, PAM投加量1mg/L, 投加顺序为快速搅拌时投加PFS, 慢速搅拌时投加PAM, 混凝反应时间14min, 静沉15min, 含铅矿坑涌水经该工艺处理后, 铅去除率可达99.05%, 出水铅浓度降至0.238mg/L, 达到国家污水综合排放标准(GB8978—1996)。

Treatment of Lead-containing mine pit water discharge by coagulation and sedimentation process

This research designed an experiment using polyaluminium chloride(PAC) and polymeric ferric sulfate(FPS), polyacrylamide(PAM) by beaker coagulation experiment to compare the three types of flocculants in the removal of lead in mine pit water discharge. The removal results from three flocculants were compared, coagulant combinations were screened based on effectiveness and economic, and PFS and PAM were determined to be the coagulant combination. Under the best PAC, PFS dosing conditions combined with PAM, the treatment effects of lead was better than using PAC or PFS alone. The added PAM improved the PAC and PFS for lead removal. The optimum lead removal conditions with PFS and PAM were at pH of 9.5, PFS dose of 200mg/L, and PAM dose of 1mg/L. The order of the experimental steps was:Rapid stirring dosing PFS followed by PAM at the slowing stirring at coagulation reaction time of 14 min and precipitation time of 15min. The removal rate of lead could reach 99.05% and the concentration of lead in effluent water was 0.238mg/L meeting the standard of Integrated Wastewater Discharge Standard(GB8978—1996).