Abstract
Two innovative tracer methods for the quantification of extraneous discharges in sewers have been proposed as routine applications within the scope of the European research project APUSS (Assessing Infiltration and Exfiltration on the Performance of Urban Sewer Systems). In order to improve the accuracy of wastewater hydrograph separation compared to conventional practice, the novel approaches use intrinsic physicochemical characteristics (stable isotopes, pollutographs) of the wastewater as a natural tracer for the differentiation of its constituting components. The methods were evaluated and tested under field conditions and have been validated in the course of a comparative experimental study. We analyse the state of development achieved and demonstrate the application of the protocols with data from a reference experiment conducted in a combined sewer catchment housing 5400 inhabitants. The article details the requirements for suitable boundary conditions and presents a comprehensive assessment of measurement uncertainties.
Acknowledgements
This study was funded by the Swiss Federal Office for Education and Science within the framework of the European research project APUSS (BBW-0.0097). APUSS was funded by the European Commission under the 5th Framework Programme and contributed to the implementation of the Key Action ‘Sustainable Management and Quality of Water’ (Energy, Environment and Sustainable Development, EVK1-CT-2000-00072). We acknowledge the municipality of Rümlang for practical support during our experiments, R. Angst, J. Keller and E. Werner for their valuable technical assistance, and R. Siegwolf and M. Saurer (Paul-Scherrer-Institut, CH) for helping with isotope analyses.