华南亚热带土壤-植被处理稳定渗沥液的现场试验

本研究采用不透水衬垫的土壤-植被层,在我国华南气候与土质条件下,验证土壤-植被灌溉工艺处理稳定渗沥液的效果,同时与同区域填埋场的膜处理工艺进行比较。在海南海口市某填埋场现场,进行了覆盖全年气候期的渗沥液生物处理出水灌溉试验及同场纳滤工序的取样测试。结果表明:比较高羊茅草、高羊茅+夹竹桃和空白3种植被,高羊茅+夹竹桃植被土壤层灌溉的水分减量率最高,以总水分(灌溉量+降雨量)和灌溉量计的减量率分别为53.2%和38.7%,而且同样具有最佳的灌溉污染物去除效率;计入灌溉水分减量贡献的COD、总氮和氨氮去除率分别为85.3%、83.0%和93.9%。该场纳滤工艺处理同一水源的稳定渗沥液,其COD、总氮和氨氮去除率分别为90.9%、87.8%和84.0%。虽然表观去除率略优于灌溉,但从污染物总量削减的角度考虑,灌溉处理更具有实质性的环境效益。

On-site Experiment of Stable Leachate Treatment by Soil-vegetation Irrigation in Sub-tropical Southern China

Through a soil-vegetation layer above the waterproof liner, under the climate and soil condition in southern China, the treatment effect of stable leachate by soil-vegetation irrigation was verified to compare with membrane treatment technology. In one waste landfill site of Haikou, Hainan, a irrigation experiment of leachate effluent after bio-treatment was carried out. The irrigation last for the whole climate year, during which the influent and effluent of leachate irrigation were analyzed, as well as the leachate effluent samples from nano-filtration. The soil-vegetation layer was divided into 3 areas, including tall fescue, mixture of tall fescue and oleander, and blank control area. The results showed that mixing vegetation-soil layer of tall fescue and oleander contributed the highest water removal rate, in which reduced 53. 2% of total water （including irrigation and rainfall） and 38. 7% of irrigation water. Also, the best removal rate of pollutants occurred in the mixing vegetation-soil layer. Calculating the water reduction of irrigation, the removal rates of COD, total nitrogen and ammonia nitrogen were 85.3%, 83.0% and 93. 9%, respectively. The stable leachate in this landfill site was treated by nano-filtration, by which the removal rates of COD, total nitrogen and ammonia nitrogen were 90. 9%, 87. 8% and 84. 0%, respectively. Although the apparent removal efficiency of nano-filtration was higher than that of irrigation, the higher substantial environmental effects were obtained in the irrigation treatment, considering the total pollution reduction.