Emerging organic contaminants in sewage sludge: Current status, technological challenges and regulatory perspectives

Sewage sludge is the source and sink of pollutants. It accumulates a large number of organic contaminants such as endocrine disrupting compounds (EDCs), persistent organic pollutants (POPs), microplastics (MPs) and pharmaceuticals and personal care products (PPCPs), thus posing threats to the ecological environment and human health. The harmlessness of sludge provides the possibility to realize the recycling of resources. In this study, the VOSviewer software is used to visualize published papers related to organic contaminants in sewage sludge. The sources and hazards of emerging pollutants in sewage sludge are outlined, as well as the current state of research on composting, hydrothermal treatment, electrochemical technology, and advanced oxidation processes applied to this area. Key challenges facing this field include the low mineralization rate of contaminants, the ecological risks posed by degradation products, reasonableness of regulations, and effectiveness of enforcement. In conclusion, the integration of existing removal technologies, exploration of degradation pathways, and toxicity assessment of degradation products are the key to achieving the harmlessness and resource utilization of sewage sludge. Additionally, it is also necessary to strengthen the international consensus on the prevention and control of emerging organic contaminants in sewage sludge, improve regulatory frameworks, enhance law enforcement, and implement comprehensive management strategies.