Source identification and mitigation options of industrial pollution in municipal sewage sludge

In Sweden, municipal sewage sludge are not applied as nutrient supply on agricultural land used for crops for human consumption, due to a resistance among consumer, farmers associations and leading producers and grocery distributors. Thus, a nationwide initiative, ReVAQ, with a wide range of different stakeholders was established in 2003. The aim was to identify approaches to be implemented to improve the quality of the sludge in order to make it possible to use municipal sewage sludge on agricultural land in a sustainable and socially acceptable manor. Here, a ReVAQ subproject, organic substances in industrial effluents to Eslöv ́s wastewater treatment plant, is investigated and the hazardous substances are identified. 42 businesses participated and lists including 901 commodities (detergents, lubricants, process chemicals, glues etc) were obtained from these businesses. The lists contained more than 2300 substances. 343 unique organic substances were selected for further evaluation. 51 of these were found to constitute potentially priority pollutants in sludge based on inherent properties and in a subsequent environmental risk assessment were 15 of these found to present a risk. Mitigation options such as legislation; environmentally sound purchasing; and treatment barriers (e.g. oil separators) are important in order to achieve an improved sludge quality.