渗滤液与城市污水合并处理过程的有机物去除特征

Study on removal characteristics of organics in leachate by co-treatment with domestic wastewater

以上海老港垃圾填埋场调蓄池的渗滤液,及其经厌氧甲烷化垃圾填埋柱循环回灌处理后的出水和其再经过混凝处理后的出水等3种不同处理水平的渗滤液为研究对象,分别以不同的比例与城市污水混合,采用好氧活性污泥法合并进行处理,对进出水的COD、UV254吸光度和溶解性有机物的分子量分布及污泥的脱氢酶活性进行了测定分析.结果表明:当渗滤液混合比例小于10%时,出水的COD和UV254吸光度随混合比例线性升高,污泥的活性相应线性降低;而当混合比例大于20%时,污泥活性阶跃降低,出水COD和UV254吸光度的升高超出线性范围.渗滤液混合比例为20%与比例为5%的混合污水相比,分子量1k～4k的溶解性有机物去除率显著降低.渗滤液与城市污水合并处理的混合比例大于10%时,微生物的有机物降解能力会受到严重损害,且常规的渗滤液生物和物化预处理不能减轻此种损害.

Leachate from the regulation pond of Laogang landfill in Shanghail, effluent from an anaerobic methanogenic lysimeter for recirculating Laogang landfill leachate and the effluent of the recirculated leachate further treated by coagulation were respectively mixed with domestic wastewater in different ratios. The COD and UV_(254) in the influent and effluent, molecular weight (MW) distribution of dissolved organic matter (DOM) and dehydrogenase activity of sludge during aerobic processing were analyzed. The results showed that COD and UV_(254) increased linearly as leachate ratio rose, while the activity of sludge decreased when leachate ratio was less than 10%; COD and UV_(254) increased beyond the linear range while activity of sludge decreased heavily when leachate ratio was more than 20%. Compared the leachate ratio of 20% with 5%, the removal rate of DOM with MW between 1?k and 4?k descended obviously. It can be concluded that if the leachate volume is higher than 10%, microorganism's activity will be seriously impaired, and the impairment cannot be eased by regular biological or physico-chemical pretreatment.