污泥放置时间对其浸提液毒性的影响

以接纳工业废水的城市综合污水处理厂污泥的水浸提液对Daphnia magna的24h急性毒性为指标，研究了该厂在不同季节运行时的污泥，放置时间对其浸提毒性的影响。结果表明，无论是春季还是冬季，污泥浸提液对Daphnia magna的急性毒性随放置时间增长，总体呈上升趋势。污泥放置1－2个月后毒性趋于稳定。利用毒性鉴别评价程序，对不同放置时间（1d、8d和64d)的污泥的浸提液，进行了毒性原因鉴别。结果表明，污泥放置时间越长，有毒重金属含量越高。GC／MS分析表明，放置1d和8d的污泥的浸提液中，有机毒物主要是含苯环的化合物，如各种取代苯胺、芳香酸生成的盐或酯以及甲基酚等，放置64d的污泥的浸提液中，有机毒物主要是含氮氧的杂环物质和小分子脂肪酸。另外，对污泥浸提毒性随放置时间变化的原因也进行了探讨。

Effects of Sewage Sludge Storage on the Toxicity of its Extracts

Agricultural application of sewage sludge is getting more and more popular in the world in recent years. But organic pollutants and heavy metals widely exist in most of the sludge, which is harmful to the ecosystem and limits the agricultural utilization of the sludge. The 24?h acute toxicity of the water extracts of municipal sewage sludge to Daphnia magna and the relation between the toxicity and the storage duration of the sludge are studied. The longer the storage duration of the sewage sludge is, the higher the acute toxicity is. But the toxicity increases slightly after one or two month storage. In order to explore the relation between the toxicants in the extracts and the storage duration, the characteristics of toxicants existing in the extracts for different storage duration (1?d, 8?d and 64?d) are tested by using toxicity identification evaluation (TIE) procedures. During the storage of the sewage sludge, more and more toxic heavy metal irons come into the extracts. And GC/MS analysis indicates organic toxicants in the extracts of 1?d and 8?d sludge are mainly aromatic compounds such as benzenamine, phenol 4-methyl, and so on, while toxicants in extracts of 64?d sludge include 1-methyl-2-pyrrolidinone, piperidinone and 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-2-benzofuranone etc. The possible reasons for the increase of the sludge toxicity are also discussed.