自来水厂石英砂滤池铊析出风险及控制技术研究

Study on risk and control technology of thallium release in quartz sand filter

通过小试研究了自来水厂石英砂滤池的铊析出风险,考察了预氧化及增设拦截筛网等处理工艺对铊析出的控制效果。研究结果表明,自来水厂的石英砂滤池在过滤时,滤料表面的活性滤膜会对水中的铊进行吸附,使其在活性滤膜中逐渐积累;滤料表面的活性滤膜脱落进入到后续工艺段后,在长时间的浸泡过程中会向水体中逐渐析出铊,且在水体受污染时,其铊的析出量明显增大;在常规处理前分别采用高锰酸钾、次氯酸钠和二氧化氯等对受污染水体进行预氧化,对铊的析出没有明显的控制效果;在石英砂滤池出水溢流堰处增设拦截筛网,能够有效控制泄漏的污泥量,从而降低铊析出的风险。

The risk of thallium release in quartz sand filter was studied and the control effect on thallium release by preoxidation and adding nets was investigated.The results show that,when the water passes through the filter,the thallium in the water will be adsorbed by the active filter membrane covered on the filter material and gradually accumulated.When the active filter membrane flows into the subsequent processes,it will gradually release thallium into the water during a long soaking process,and the amount of thallium release increased significantly when the water was polluted.Preoxidation of polluted water by potassium permanganate,sodium hypochlorite and chlorine dioxide respectively before conventional treatment all have no obvious control effect on thallium release.Adding nets to the overflow weir of quartz sand filter can effectively control the sludge leakage,thereby reducing the risk of thallium release.