DIMES

Diffuse pollution of Micropollutants from sewer systems (Dimes)

Background information

Micropollutants belong to a group of substances possibly affecting human health and the environment in very small concentrations. Important examples are pharmaceuticals, biocides or flame retardants and radio-opaque substances. For a subset of these active agents that are readily biodegradable continuous discharges like waste water treatment plants are of minor importance. Instead wet-weather dischargers will likely contribute the majority of the annular load originating from urban settlements. Of particular interest are combined sewer overflows because in the combined system foul sewerage is mixed with surface runoff. During a relevant number of storm water events combined sewer overflows discharge diluted foul sewerage directly into the receiving water body.

Aim

Supported by the federal bureau of the environment the study aims to quantify emitting loads of micropollutants for Switzerland. In this framework we look at separate systems and combined systems.

Expected impact

Effective and cost-efficient water quality control requires to simultaneously optimize the design and operation of both waste water treatment plants and urban drainage resulting in an integrated urban water management system. After micropollutants originating directly from sewers are quantified their environmental impact can be evaluated and their relevance compared to point-sources can be stated. If necessary, this research provides a fundament to initiate a transfer process acknowledging the special requirements of emerging pollutants and large infrastructure.