Illicit discharge detection and elimination: Low cost options for source identification and trackdown in stormwater systems

Permit regulations in the U. S. for Municipal Separate Storm Sewer Systems (MS4) require the MS4 to develop a program that detects and eliminates illicit discharges (e. g., improper wastewater connections) into the storm sewer system. Municipalities are interested in cost-effective methods to meet the permit requirements of this federal mandate. Our demonstration project with municipalities in Western New York State evaluated low cost options for illicit discharge trackdown. First, a visual reconnaissance was used to document flowing stormwater outfalls in dry weather. Subsequently, a sampling program was conducted, in combination with decision-making tools, to identify possible sources of illicit discharges. Colorimetric techniques were tested for a number of chemical parameters and the Coliscan Easygel (R) system was tested for E. coli analysis. Results from these various cost-effective analytical techniques were compared with analysis by standard methods. The E. coli test, in particular, had good precision and was useful in trackdown.