污泥苯酚的释放特征及其风险评价与控制

The release characteristics of phenol in sewage sludge and its risk assessment and control

在测定不同类型污泥中苯酚含量的基础上,通过模拟试验,研究自然状态和不同干化温度下污泥苯酚的释放特征及其影响因素,同时对污泥释放苯酚进行致癌风险评价,并提出收集与控制措施.结果表明,被测污泥中苯酚的含量范围在0.17～3.22μg/g之间,污泥中苯酚含量呈现出随暴露在空气下时间的增加而降低的趋势;污泥在低温干化时,苯酚释放量较低,主要来源于污泥中原有的苯酚,当污泥在较高温度下干化时,释放的苯酚主要来源于污泥的热解作用;杭州市政污泥在350℃干化时的苯酚释放量,对男、女性暴露人员均存在较高的致癌风险.降低污泥干化温度,控制苯酚的释放与扩散,并通过综合处理措施,可以有效地防治污泥干化过程苯酚污染对人体健康造成的威胁.

The phenol contents in several types of sewage sludge were determined. The characteristics of phenol release under natural condition and at various temperatures,as well as factors that impact this process were assessed. The carcinogenic risks due to the phenol release were evaluated,based on which a number of potential control measures were proposed. Phenol content in the sewage sludge ranged from 0.17 to 3.22μg/g. The phenol release decreased as the aerial exposure of sewage sludge prolonged. When dried at low temperature,the released phenol was mainly derived from the phenol pre-dissolved in the sewage sludge. When dried at higher temperature,the primary phenol release was resulted from the pyrogenation of organic matters contained in the sewage sludge. The current sewage sludge drying protocol adopted by the Hangzhou municipal sewage management required a drying temperature at 350℃,which exerted high carcinogenic risks to workers with exposure potentials. By lowering the temperature of sewage sludge drying,it could effectively lower the health harm risks due to the phenol release in this process.