Measurement and evaluation of pollutants in landfill leachate.

我们对三个固体废物处理场的渗滤液进行了多次调查。垃圾渗滤液中各种重金属的浓度都很低，仅为每升微克。虽然没有发现个别金属违反日本排放标准，但渗滤液或处理后的渗滤液中总重金属的浓度仍高于周围水环境。处理后的出水浓度与原渗滤液浓度相当。考虑到无机金属络合物的存在，计算了渗滤液中金属的最大溶解度。金属的溶解度足够高，并不是决定混凝后浓度的限制因素。与纯化学金属相反，较高pH的混凝不能成功降低渗滤液中金属的浓度。渗滤液中的重金属，特别是镍和铜，与有机物结合在一起，因此，除非有机物被去除，否则它们仍留在溶液中。研究了纳滤技术在渗滤液处理中的应用。用低截留率纳滤膜分离金属和毒性较小的盐是可能的。我们还用GC/MS测定了有机微污染物。每个位置都检测到塑料添加剂。具有较低辛醇-水分配系数的疏水性较小的化合物的浓度随着处理时间的推移而降低。在渗滤液中检测到高水平的消毒副产物形成潜力。垃圾渗滤液的处理工艺对塑料添加剂非常有效，但对消毒副产物的形成潜力不大。

We investigated the leachates from three solid waste disposal sites for several times. Various heavy metals in the landfill leachates were measured up to very low concentration level of microgram per liter. Though no violation to Japanese effluent standard was found in respect of individual metal, leachate or treated leachate still contains higher concentration of total heavy metals than surrounding water enviromment. The effluent concentration after treatment was of the same order of raw leachate. Maximum metal solubilities in leachate were calculated taking the presence of inorganic metal complexes into account. Solubilities of metals were enough high and they were not the limiting factor determining concentrations after coagulation. The coagulation with higher pH was not successful in reducing concentration of leachate-origin-metals contrary to the case of pure chemical metals. The heavy metals especially nickel and copper in the leachate were associated with organic matters and consequently they remained in solution unless organic matters were removed. Application of nanofiltration to leachate treatment was studied. It was possible to separate metals from less toxic salts by low retention nanofiltration membranes.We also measured organic micropollutants by GC/MS.Plastic additives were detected at every site. Less hydrophobic compounds with low octanol-water partition coefficient were decreased in concentration with time elapsed from disposal. High level of disinfection by-products formation potential was detected in leachate. The treatment process of landfill leachate was very effective for plastic additives but not effective for disinfection by-products formation potential.