BROWARD COUNTY, FLORIDA SUCCESSFUL I/I REHABILITATION PROGRAMS

Various public utilities in Broward County are implementing sanitary sewer rehabilitation programs. Broward County Office of Environmental Services (BCOES) owns and operates the 60 million gallons per day (mgd) North Regional Wastewater Treatment Plant (WWTP). BCOES is responsible for the operation of the unincorporated Broward County's sewer system, which consists of approximately 1,600,000 feet and over 6,200 manholes. During the last 5 years, BCOES has undergone an extensive program to successfully reduce the infiltration and inflow (I/I) into its sewer system. BCOES retained Hazen and Sawyer, P.C. to perform a desktop study to evaluate the I/I in the regional collection system. The study identified the systems with excessive I/I. The study also led to the implementation of the I/I control program for the BCOES wastewater collection system and the initiation of similar programs by some of the large users contributing flows to the regional treatment plant.The I/I control program has three phases: investigation, evaluation and rehabilitation. In conventional programs, flowmeters are strategically located in the sewer system for continuous flow measurements. A less expensive approach was followed in the BCOES program. Instantaneous night flow measurements were taken at each pump station. Ninety-nine of the 162 sewer system areas evaluated were included in the sewer system evaluation survey (SSES). A modified SSES was implemented for the BCOES sewer system. One hundred percent of the manholes were inspected. Also, 100 percent of the pipelines were smoke tested and inspected with TV cameras, including suspect laterals.Good project management and detailed coordination have been the key to the project success to date. Up to 6 different contractors have been issued work tasks, utilizing 9 different rehabilitation technologies. Contractor procurement has ranged from bidding, to piggy backing, to sole sourcing. As a result of the SSES, a total of 7,796 repairs were recommended at a total cost of 25 million. BCOES decided to implement 4,345 repairs by the year 2001, at an approximate cost of 10,500,000. BCOES initiated the rehabilitation program in 1996, and is committed to continue with their sanitary sewer rehabilitation program. By eliminating 5 to 7 mgd (approximately 50 percent of the total I/I), BCOES could realize potential savings of 32 million over a 20 year period.