8:30-11:55 a.m.
Sewer Rehabilitation Strategies
George Kurz, P.E., DEE, Consulting Engineer, Sewer Capacity Management
Pat Stevens, P.E., Vice President Engineering, ADS Environmental Services
This seminar includes five related presentations:

  • State-wide Study Finds 45% I/I Wastes Revenue and Steals Capacity
  • A 10-Step Plan for a Municipal I/I Reduction and Sewer Rehabilitation Program
  • “If I had this to do over . . .” 12 Steps to Successfully Measure Effectiveness of Sewer Rehabilitation
  • Nashville & Brentwood – Removing 4.1 Billion Gallons of I/I
  • Service Laterals as a Critical Part of the Rehab Program

A new state-wide study of I/I in Tennessee municipal collection systems showed an average of 45% I/I in collection systems. Two-thirds of the systems had more than 50% I/I. These systems likely are representative of many collection systems in the USA. This level of leakage should provide a powerful incentive for municipalities to measure the condition of their sewers and develop a strategy for corrective action.

This seminar uses the results from work in small and large municipal systems to teach a strategy for conducting a successful sewer rehabilitation program for SSO and I/I reduction. The strategy is based on extensive before-after flow measurements for 30 project areas, including 110 miles of sewer lining, and manhole and service lateral rehabilitation on all lined sewers. The strategy proved the value of the system approach for aggressive rehabilitation of deteriorated sewers targeted in priority basins, versus a “find-and-fix” approach for scattered individual pipe defects. Municipal sewer O&M savings generally resulted in a payback period of about 11-13 years. The approach has been formulated into a logical and intuitive 10-step strategy.

Before-after flow monitoring, and rehabilitation of sewer service laterals were found to be critical for successful programs. The presentations will identify pitfalls for flow/rainfall monitoring and explain the analysis of monitoring data in general terms that can be applied to improve the final results, regardless of equipment brand. Sewer service laterals were found to be significant sources of I/I, and a pilot study will be explained which isolated and measured such I/I contribution.

kurzGeorge Kurz, P.E., DEE, has 40 years of experience in state and local government, sewer service contracting and consulting engineering. For 30 years, he has focused on the development of a strategic approach for eliminating I/I in municipal sewer systems and standard methods for measuring effectiveness of rehabilitation using flow monitoring.


stevensPat Stevens has worked in the environmental field since 1970 in both the public and private sectors. Currently he is vice president of Engineering for ADS Environmental Services, which specializies in measuring sewer performance for cities throughout the country. He has a B.S. in Aeronautical Engineering and an M.S. in Environmental Engineering, both from Purdue University.


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