LESSONS LEARNED IN 25 YEARS OF SANITARY SEWER INVESTIGATION/REHABILITATION

RJN Group, Inc. has completed sanitary sewer system investigation and rehabilitation on over 100 Million linear feet of sanitary sewer in the last 25 years. These projects have included a wide range of local climatic conditions, pipe age and material, and level of previous investigation/rehabilitation. The key variables in each of these investigation/rehabilitation programs were as follows:Inflow source distribution/temporary flow meter spacingRainfall/inflow design storm projectionsPrivate sector/public sector source distributionSystem rehabilitation proceduresSystem rehabilitation costsA representative sample of 100 projects was analyzed and included systems in Illinois, Arkansas, Massachusetts, Virginia, Maryland, Oklahoma, Florida, Georgia, Louisiana, Iowa, Indiana, Kentucky, Kansas, Missouri, Ohio, and Connecticut. Each of these projects contributed to the “lessons learned” matrix for successful I/I reduction programs, with success being defined as when infiltration/inflow reduction levels predicted in the investigation study were equaled or exceeded as measured in post-rehabilitation flow monitoring. Statistics gathered by analyzing each of the representative projects were used to draw conclusions about the investigation and rehabilitation procedures that are most likely to result in successful sewer system rehabilitation programs.