组合工艺削减垃圾渗滤液的毒性试验

Experiment on the way for reducing the toxicity of landfill leachate via the integrated process

利用斑马鱼胚胎及幼鱼评价垃圾渗滤液的生物毒性,并结合理化指标对混凝沉淀-厌氧-电化学氧化-好氧组合处理工艺的毒性削减能力进行评估。结果表明,经组合工艺处理后,垃圾渗滤液的化学需氧量、氨氮去除率分别达93.28%和96.84%,出水水质满足排放标准。垃圾渗滤液对斑马鱼胚胎和幼鱼的毒性单位分别由63.69和99.01降至12.78和19.49,组合工艺的毒性削减率分别为79.93%和80.32%。研究表明,组合工艺能显著降低垃圾渗滤液的毒性。

The present paper is aimed to make an assessment of the capability of the coagulant sedimentation-anaerobic-electrochemical oxidation-aerobic integrated process for reducing the toxicity of the landfill leachate.For this purpose,we have chosen zebrafish embryo and larvae as the testing samples for the testing goals.And,then,we have determined the half lethal concentration（LC_（50））and the half maximal effective concentration（EC_（50））of the landfill leachate influent and effluent in the different treating stages.Later,in accordance with their physical and chemical properties of the said leachate,we have done the careful assessment of the toxicity reduction capability of the leachate in the different stages of the entire process in the toxic unit（TU）.The results of our experiment and investigation show that the removal rates of the chemical oxygen demand（COD_（Cr））and the ammonium nitrogen（NH_4~＋-N）content rate can be promoted so high as up to 93.28%and 96.84%,respectively,so as for the effluent quality to meet the standard for the Pollution Control on the Landfill Site of the Municipal Solid Wastes（GB 16889—2008）.What is more,the toxicity testing results we have gained also indicate that the LC_（50）mortality rates of the above-mentioned zebrafish embryo in the effluent from the fore-mentioned four stages may turn to be 2.78%,3.56%,5.71%and 7.82%,with the EC_（50）hatching rates from those 4 stages respectively being 2.44%,3.16%,5.46%and 7.64%.On the other hand,since the effluents from the coagulation sedimentation and the anaerobic tanks are potentially producing some teratogenic effects on the zebrafish embryo,which seems to be abnormal in the evolutionary phenomena and in turn manifested in the symptoms of pericardial effusion,tail bending and so on.The LC_（50）mortality rates of the zebrafish larvae in the above said 4 stages can be found merely equal to 1.44%,1.82%,3.54%and 5.13%,correspondingly.And,in the similar manner,the TU of zebrafish larvae and embryo has been found decreased from 63.69 and 99.01 to 12.78and 19.49,respectively.That is,the toxicity rates have been found reduced by 79.93%and 80.32%through integrated processing,in which the coagulant sedimentation and the electrochemical oxidation treating can be expected to reach the greatest contribution.Besides,no abnormal situation has been observed in the zebrafish embryo of the final effluent.Hence,it can be said that the integrated processing can significantly reduce the toxicity of the landfill leachate.