城市污泥植物处理对地表径流和下层土壤的影响

Effect of phyto-treatment of municipal sewage sludge on surface runoff and sub-soil

城市污泥的农业利用逐渐成为世界城市污泥处理处置的最具前景的方式之一。通过设置无污泥＋不种植物、污泥＋不种植物、污泥＋东南景天单种、污泥＋东南景天与香芋套种4个处理,对污泥植物处理系统的地表径流以及各处理1年后的下层土壤（20-40 cm）进行了监测。研究结果表明：地表径流中的TN、TP和COD的含量随着时间的推移均有不断下降的趋势,其中,地表径流中的TP含量超出国家污水综合排放中的二级标准。地表径流中Zn、Cd、Cu和Pb的含量随着时间的推移略有上升的趋势,但它们的含量远低于国家污水综合排放标准中的二级标准。处理1年后下层土壤中的氮磷钾和有机质含量明显提高,下层土壤中的Zn、Cd、Cu和Pb含量也有一定程度的增加。

Agricultural application of municipal sewage sludge（MSS）has become one of the best ways to dispose MSS in the world.A field experiment was conducted to evaluate impacts of phyto-treatment of MSS on chemical properties of surface runoff and sub-soil（20~40 cm）.Fresh MSS were treated for about one year by phyto-treatment system,including the treatments of no MSS ＋ no plant,MSS ＋ no plant,MSS ＋ Sedum alfredii,and MSS ＋ co-planting of Sedum alfredii and Alocasia marorrhiza.The contents of TN,TP and COD in the runoff decreased gradually.The content of TP in the runoff was higher than the secondary grade limit of the Chinese National Comprehensive Standards for Wastewater Discharge（GB 8978-1996）.Zn,Cd,Cu and Pb contents in the runoff were lower than the secondary grade limit of the same standards（GB 8978-1996）.The contents of N,P,K,Zn,Cd,Cu,Pb and organic matter in the sub-soil increased after phyto-treatment of MSS.