Indirect discharges are discharges from, among others, companies that end up in surface water via the sewer system and the WWTP. These types of discharges can be problematic, particularly for substances that are not or hardly removed by WWTPs (such as PFAS and other micro-pollutants).

 

Together with AD eco advies, and commissioned by STOWA and the Ministry of Infrastructure and Water Management, we have developed a method for source tracing of PFAS discharges via measurements in the sewer system. The methodology can be used for wastewater treatment plants with elevated PFAS loads where the potential source is not apparent. By taking measurements step-by-step upstream in the sewer system and combining these findings with local knowledge regarding the activities taking place, the search area becomes progressively smaller. The method is described in an H2O article.