Wong M H, Li M M, Leung C K, Lan C Y
Department of Biology, Hong Kong Baptist College, Kowloon.
Biomed Environ Sci. 1990 Dec;3(4):429-42.
Soils with different textures (sandy, loamy, and clay soils) were used as filters to attenuate leachate from the Gin Drinkers' Bay landfill. They were used to pack columns of different depths: 0.2, 0.6, and 1.0 m. Eight millimeters of leachate was drained into the soil columns each day for 56 days. The percolated leachates were collected weekly and their properties analyzed. It was revealed that the properties became rather stable at Day 28 and therefore only the data from Day 28 are presented. The effluents from the loamy and clay columns with depths of 0.6 and 1.0 m contained significantly lower (P less than 0.05) ammonia contents and had lower chemical oxygen demand than those from sandy soil columns. Moreover, the depth of the columns of loam and clay did not show a significant difference (P greater than 0.05). Sandy soil was the least effective in attenuating the leachate. The efficiency of all the soil columns decrease as the soil depth decreased. It was also noted that growing of tree seedings (Acacia confusa) could further improve the efficiency of the loamy soil, especially for the removal of Na. The phytotoxicity of the raw and percolated leachate was evaluated using seed germination of two plant species (Brassica chinensis and Lolium perenne) and the growth of an uncellular green alga (Chlorella pyrenoidosa). In general, the raw leachate was toxic and inhibited seed germination and root growth of the two plant species and the growth rate of the unicellular green alga. The toxicity was due to the high levels of ammonia-nitrogen. COD, iron, manganese, and sodium ions. Percolated leachate, especially from loamy and clay soil columns, exhibited a decrease in phytotoxicity. Clay or loamy soil columns of 0.6-m soil depth seemed to be sufficient to remove the phytotoxic substances in landfill leachate.
不同质地的土壤（砂土、壤土和黏土）被用作过滤器，以衰减醉酒湾垃圾填埋场的渗滤液。它们被用来填充不同深度的柱体：0.2米、0.6米和1.0米。每天有8毫米的渗滤液排入土壤柱体，持续56天。每周收集渗滤后的渗滤液并分析其性质。结果表明，在第28天性质变得相当稳定，因此仅呈现第28天的数据。深度为0.6米和1.0米的壤土柱体和黏土柱体的流出物中氨含量显著更低（P小于0.05），且化学需氧量低于砂土柱体的流出物。此外，壤土和黏土柱体的深度没有显示出显著差异（P大于0.05）。砂土在衰减渗滤液方面效果最差。所有土壤柱体的效率随着土壤深度的减小而降低。还注意到种植树苗（台湾相思树）可以进一步提高壤土的效率，尤其是对于钠的去除。使用两种植物（小白菜和黑麦草）的种子发芽以及单细胞绿藻（蛋白核小球藻）的生长来评估原渗滤液和渗滤后渗滤液的植物毒性。一般来说，原渗滤液有毒，会抑制这两种植物的种子发芽和根系生长以及单细胞绿藻的生长速率。毒性是由于高含量的氨氮、化学需氧量、铁、锰和钠离子。渗滤后的渗滤液，尤其是来自壤土和黏土柱体的，植物毒性有所降低。0.6米土壤深度的黏土或壤土柱体似乎足以去除垃圾填埋场渗滤液中的植物毒性物质。
