title: Estimating sewer leakage from continuous tracer experiments.
abstract: Direct measurements of sewer leakage with continuous dosing of tracers are often considered too imprecise for practical applications. However, no mathematical framework for data analysis is reported in literature. In this paper, we present an improved experimental design and data analysis procedure together with a comprehensive framework for uncertainty assessment. Test runs in a 700 m-long watertight sewer showed no significant bias and a very high precision of the methodology. The standard error in the results was assessed to 2.6% of the labeled flow with a simplified model. It could be reduced to 1.2% when a dynamic data analysis procedure was applied. The major error contribution was caused by transient transport phenomena, which suggests that careful choosing of the experimental time is more important than the choice of a very specific tracer substance. Although the method is not intended to replace traditional CCTV inspections, it can provide complementary information for rational rehabilitation planning.
authors.affiliation: Swiss Federal Institute of Aquatic Science and Technology (Eawag) and Swiss Federal Institute of Technology (ETH), 8600 Dübendorf, Switzerland. joerg.rieckermann@eawag.ch
authors.forename: Jörg
authors.initials: J
authors.lastname: Rieckermann
authors.forename: Vojtech
authors.initials: V
authors.lastname: Bares
authors.forename: Oliver
authors.initials: O
authors.lastname: Kracht
authors.forename: Daniel
authors.initials: D
authors.lastname: Braun
authors.forename: Willi
authors.initials: W
authors.lastname: Gujer
mesh_terms: D003198:Computer Simulation; D003661:Decision Support Techniques; D004323:Drainage, Sanitary; D004784:Environmental Monitoring / Q000379:methods*; D015203:Reproducibility of Results; D012107:Research Design; D012722:Sewage; D014865:Waste Disposal, Fluid; D014873:Water Pollutants / Q000032:analysis
chemical_list: D012722:Sewage; D014873:Water Pollutants