ABSTRACT

Mature landfill leachate usually contains high levels of both recalcitrant organic matters and nitrogen compounds, which are hard to be removed simultaneously. In view of the difficulty, this study explored an innovative alternative that treated organic matters and nitrogen compounds separately by combining ferric trichloride (FTC) and polyacrylamide (PAM) coagulation with activated coke adsorption. Our study results have shown that the combination of chemical coagulation (750 mg/L of ferric trichloride and 2.0 mg/L of anionic polyacrylamide at pH = 5) with activated coke adsorption (5 g per 100 mL) was able to remove total organic carbon (TOC), chemical oxygen demand (COD), and colority by 91%, 57%, 100%, respectively. The removal efficiency (R.E.) of humic- and protein-like matters both exceeded 95%. Meanwhile, nitrogen compounds, such as nitrite and ammonia nitrogen, were mostly retained in the effluent. They could either be recovered as value-added products through technologies such as negative pressure steam-stripping or removed through methods such as air stripping and ion exchange. Overall, the proposed coagulation-adsorption process may provide a feasible alternative for tackling the worldwide concern over the secondary pollution caused by mature landfill leachate and its effective disposal.

摘要

成熟的垃圾渗滤液通常含有高含量的顽固性有机物和氮化合物，难以同时去除。针对难点，本研究探索了一种创新的替代方案，将三氯化铁（FTC）和聚丙烯酰胺（PAM）混凝与活性焦吸附相结合，将有机物和氮化合物分开处理。我们的研究结果表明，化学混凝（750 mg/L 三氯化铁和 2.0 mg/L 阴离子聚丙烯酰胺，pH = 5）与活性炭吸附（5 g/100 mL）的组合能够去除总有机碳(TOC)、化学需氧量 (COD) 和色度分别增加 91%、57%、100%。腐殖质和类蛋白质物质的去除效率（RE）均超过 95%。同时，含氮化合物，如亚硝酸盐和氨氮，大部分保留在流出物中。它们既可以通过负压汽提等技术作为增值产品回收，也可以通过空气汽提和离子交换等方法去除。总体而言，所提出的混凝吸附工艺可能为解决世界范围内对成熟垃圾渗滤液及其有效处置造成的二次污染的担忧提供一种可行的替代方案。