College of Resources and Environment, Shanxi University of Finance and Economics, Taiyuan 030006, China.
Int J Environ Res Public Health. 2022 Apr 1;19(7):4236. doi: 10.3390/ijerph19074236.
The agricultural use of sewage sludge has become an economic disposal method used worldwide. However, heavy metals contained in sewage sludge have become the crucial limiting factors for this way of disposal. This study showed that regulatory limit values are not enough to determine whether sewage sludge is suitable for agricultural use; risk assessment and potential analysis should be applied. Correlation analysis and hierarchical cluster analysis (HCA) should also be performed to identify heavy metals' sources and show their influence on sewage sludge utilization. Samples were collected from 13 wastewater treatment plants (WWTPs) located in central Shanxi Province. Results indicated that the mean contents of heavy metals in sewage sludge were all less than the limit threshold of China. According to the monomial potential ecological risk coefficient (), the agricultural use of sewage sludge had low ecological risks for all heavy metals, except for Hg and Cd. Based on the potential ecological risk index (RI), only three stations had moderate risk, other nine stations all had higher potential risk. The mean potentials by all heavy metals were all beyond 10 years, which is the limit of the maximum application time specified by China. Combining all heavy metals, only one station's potential was less than 10 years. Although the contents of heavy metals were all within the threshold values, large quantities of sewage sludge are not suitable for agricultural use. Coal-related industries, which were the main sources of Hg and Cd, greatly affected the agricultural use of sewage sludge.
农业污泥的应用已成为一种全球范围内经济的处理方法。然而，污泥中含有的重金属已成为这种处理方式的关键限制因素。本研究表明，监管限值不足以确定污泥是否适合农业应用；应进行风险评估和潜在分析。还应进行相关分析和层次聚类分析（HCA），以确定重金属的来源，并显示其对污泥利用的影响。从山西省中部的 13 个污水处理厂（WWTP）采集了样本。结果表明，污泥中重金属的平均含量均低于中国的限值阈值。根据单项潜在生态风险系数（），除 Hg 和 Cd 外，所有重金属的农业污泥利用均具有低生态风险。根据潜在生态风险指数（RI），只有三个站具有中等风险，其他九个站均具有更高的潜在风险。所有重金属的平均潜力均超过 10 年，这是中国规定的最大应用时间限制。综合所有重金属，只有一个站的潜力不足 10 年。尽管重金属含量均在阈值范围内，但大量的污泥不适合农业应用。与煤炭相关的行业是 Hg 和 Cd 的主要来源，这极大地影响了污泥的农业应用。
