城市污水处理厂污泥中重金属海水浸出影响因素的研究

研究不同因素对城市污水污泥中重金属浸出的影响可以为城市污水污泥最终处理方法的选择、污泥投海对海洋环境的影响评估和海洋生态环境保护提供一定的数据支撑。为了解不同因素对污水污泥中重金属浸出情况的影响,以上海7处污水处理厂的污水污泥为研究对象,采用改进的水平振荡法,探讨了海水温度、盐度和微生物活动对污水污泥中重金属浸出的影响。结果表明,由于不同季节海水温度的差异,而温度影响重金属的存在形态,污泥中Zn和Hg在水温较高的夏季释放的较多,Cu、Cd、Pb和As则在春秋时释放的较多;海水盐度的高低影响海水中电解质的浓度和部分生物体内相关酶的活性,因此污泥在低盐度水域环境中释放出较多的Zn、Cu、Pb和Cd;同时细菌等微生物在污水污泥中可能会发生氧化、硝化等一系列生理生化反应,因此会影响重金属在污水污泥中的存在形态和环境,灭菌后的污泥较未灭菌时更易释放出Zn、Cu、Hg和As。

Understanding of the influences on the leaching ability of heavy metals from sewage sludge of municipal wastewater treatment plant in seawater

This study is aiming to describe the different influences on the leaching process of heavy metals from urban sewage sludge, which mainly conduce to the establishment of hazard-free treatment strategy of sewage sludge and a framework of marine environment protection. The modified horizontal extraction procedure was utilized to study the impact of temperature, salinity and microbial activity on the leaching of sewage sludge-associated heavy metal which collected from seven typical waste water treatment plants (WWTPs) in Shanghai. The results indicated that 1) the releasing of Zn and Hg may dominant in summer and the releasing of Zn, Cu, Pb and Cd may dominant in spring and autumn according to the temperature-based experiment; 2) Salinity in seawater could affect the electrolyte concentration which mean that Zn, Cu, Pb and Cd were trend to release in sea water with low salinity. 3) Microbial activities were conductive to the releasing of Zn, Cu, Hg and As from sewage sludge.