1Quantifying exfiltration from leaky sewers with artificial traces

A novel approach to directly quantify exfiltration from leaky sewer systems is presented. The loss of wastewater is computed using a mass balance for an artificial tracer substance. The method is developed and tested and an application study for validation purposes is analysed. It is shown that the use of sodium chloride as a tracer implies certain drawbacks that mainly originate from the varying natural background concentrations. Problems concerning the experimental procedure and data analysis are identified and discussed. Further development of the method should concentrate on the assessment of the measurement uncertainty