Spatial Distribution Characteristics and Potential Risk Assessment of Heavy Metals in Sludge of Shanghai Sewage Treatment Plant: A Case Study

Sewage treatment is an important indicator of the urban environment and an important method of sustainable development. In this paper, the spatial distribution characteristics of 8 heavy metals in sewage sludge from 44 sewage treatment plants in Shanghai were analyzed. The pollution degree and potential ecological risk of heavy metals in sludge were evaluated by the Nemerow comprehensive pollution index and Hakanson potential ecological risk index. First, the single factor pollution index of heavy metals was ranked. The Nemerow comprehensive pollution index showed that five sewage treatment plants in Nanxiang, Dongqu, Liantang, Songjiang west, and Xinhe were heavily polluted. Second, the single factor potential ecological risk index of each heavy metal was analyzed. Finally, it is concluded that in the monitoring and control of sewage treatment, Shanghai should pay attention to the sewage treatment plants with high potential ecological risks and gain an excellent performance in the reduction in the emissions of pollution sources, so as to improve environmental quality and reduce the potential ecological risks. This paper provides the basis for studying the characteristics of heavy metal pollution of sewage sludge.

Automated summary

This paper analyzed the spatial distribution characteristics of 8 heavy metals in sewage sludge from 44 sewage treatment plants in Shanghai. The pollution degree and potential ecological risk of heavy metals in sludge were evaluated using the Nemerow comprehensive pollution index and Hakanson potential ecological risk index. The results showed that five sewage treatment plants were heavily polluted and measures should be taken to reduce pollution emissions and improve environmental quality to reduce potential ecological risks. This study provides a basis for studying the characteristics of heavy metal pollution in sewage sludge.