Measured I&I Reductions using Various Trenchless Technologies

There are few long-term flow studies on the measured impact of various types of sewer rehabilitation that account for seasonal and antecedent conditions in a meaningful manner. This work will share the true measured impact of various commonly used trenchless technologies, with a special emphasis on addressing both the private and the public portions of the laterals, as well providing construction cost data against which to assess cost/benefit of each project. This paper shares the evaluation results of nearly a decade of ongoing rehabilitation effectiveness flow monitoring. Flow reduction and cost to construct/rehabilitate data from approximately two dozen projects using various combinations of trenchless rehabilitation methods are presented. Several of these data sets include continuous flow performance data collected since 2004. Specifically shared information includes:• The measured effect on Inflow and Infiltration (I&I) from holistically rehabilitating every aspect of a sewer system, including sewer mains, tap connections, manholes, and both public and private lateral sewers. The percent of I&I removal data are presented relative to total I&I volume and baseline infiltration.• The impact of seasonal and antecedent conditions on I&I as demonstrated using both a pre- vs. post- flow data comparison and a normalizing control basin methodology, including an explanation of how the two methodologies are implemented.• The measured difference in I&I reduction effectiveness and associated costs when rehabilitating both main line and lateral sewers as opposed to only rehabilitating the main line sewers. The measured changes in I&I leakage (I&I creep)over the years following holistic rehabilitation to quantify the longevity of rehabilitation I&I benefits.