垃圾填埋场覆盖层灌溉处理渗滤液的试验研究

在模拟的填埋场封场覆盖层上灌溉处理不同强度的渗滤液稀释液，研究其水量减量和主要污染物COD和NH3-N的去除效果。结果表明：一个生长季内，灌溉水量负荷12 mm/d条件下，裸土覆盖层的水量减量负荷均为7 mm/d左右，狗牙根覆盖层的水量减量负荷为7.7~11 mm/d，渗滤液原液灌溉处理时为7.7 mm/d；而灌溉渗滤液的强度从低到高，狗牙根生物量先增大后减小，狗牙根覆盖层的水量减量负荷与其生物量正相关；裸土覆盖层的COD去除率为65 %左右，NH3-N去除率为70 %~93 %；狗牙根覆盖层的COD去除率为68 %~93 %，NH3-N去除率为89 %~99 %； NH3-N的去除途径主要是转化为硝态氮和被植物吸收。渗滤液覆盖层灌溉处理有良好的水量减量和主要污染物去除效果，且有植被时效果更佳，表明填埋场封场覆盖层灌溉处理渗滤液是可行的。

EFFECTS OF THE RECIRCULATED LANDFILL LEACHATE BY IRRIGATION

The study was carried out on the volume reduction and main pollutants removal of recirculated landfill leachate with different diluted concentrations by irrigation on the soil planted with and without Cynodon dactyton. The results showed that during one field season, the average volume reduction rate of the recirculated landfill leachate by soil planted withCynodon dactytonwas 7.7~11 mm/d, and among it the undiluted leachte one was 7.7 mm/d, while 7 mm/d by soil without vegetation, and the former was correlated with the dry weight of the grass; the dry weight of the recirculated landfill leachate-irrigated grass was larger than the tap water-irrigated one, and decreased with rising of leachate concentration; 89% ~99% of NH3-N and 68%~93% of COD in the recirculated landfill leachate was removed by the soil withCynodon dactytonrespectively, while 70% ~ 93% of NH3- N and about 65% of COD by the soil without vegetation. NH3-N was removed mainly by conversion to NOx-N and vegetation intake.Recir- culated landfill leachate irrigation benefits to its volume reduction and pollutants removal, especially on soil withCynodon dactyton. The results show that it is feasible to irrigate the landfill closure system with re- circulated landfill leachate in practice.