Inflow and Infiltration Reduction - In it for the Long Haul

In the 1980s, subsequent to the passage of the Clean Water Act, the City of Elmhurst was the subject of a Consent Decree to remove significant Inflow and Infiltration from its sanitary system. Much of the City had previously been combined, and while the City had been completely de-combined, there remained 30 permitted overflows (known as Emergency Sewer Overflows or ESOs) within the system which operated frequently. In an effort to reduce the number of these ESOs while at the same time addressing the excess peaking factors, RJN Group undertook a comprehensive SSES study in 1987 and 1988 that comprised flow monitoring, smoke testing, manhole inspection and building inspection. Subsequent to this study, downspouts were disconnected, storm sumps and 'laundry' combination sumps were disconnected, over 90% of the manholes were rehabilitated, remaining direct storm cross-connections removed and a system of relief sewers were constructed.