A COMPARATIVE ANALYSIS OF SEWER REHABILITATION STRATEGIES Application, Selection, and Effectiveness in Practice

It has been almost 30 years since the passage of the Clean Water Act (PL 92–500) ushered in a heighten concern about the impact of infiltration and inflow on the performance of sewers. Over this period thousands of sewer systems have been evaluated and rehabilitated to varying degrees using numerous technologies and approaches. Historically the decision as to the rehabilitation method selected for implementation has been based on the recommendations of suppliers of rehabilitation services and technologies. To promote their products or services these suppliers have developed guidelines and specifications for application of their respective systems. Independent guidance concerning selection, design, and the expected effectiveness of the various rehabilitation methods and technologies is often limited. Only in recent years have efforts been undertaken to objectively assess the actual in-service performance and effectiveness of various sewer rehabilitation strategies and technologies and to identify the factors that impact performance and contribute to their effectiveness.This paper presents an objective review of a number of completed rehabilitation projects in United States that have been placed in-service over the past 30 years. Available results concerning application, performance and overall effectiveness were evaluated to assess the applicability, selection and design considerations of various rehabilitation strategies. This evaluation was based on observed effectiveness and where available measured performance of completed sewer rehabilitation projects. Using the results of this evaluation, the authors have characterized the factors which influence overall performance of sewer rehabilitation projects.