It’s Been Five Years. How are We Doing?

In 2008, Sanitation District No. 1 of Northern Kentucky (the District), which serves over 250,000 people in Campbell, Kenton, and Boone Counties, developed and implemented an aggressive Continuous Sewer Assessment and Rehabilitation Program (CSAP). The program was developed a part of the CMOM Program required as part of a Consent Decree with USEPA Region 4 and the Kentucky Division of Water (KDOW) to address CSOs and SSOs in the sewer system. In addition to being a CMOM requirement, the program serves as a best practice for SD1 to help achieve the highest level of service to its customers.The goal of the program was to move SD1 into a more proactive mode of sewer assessment and rehabilitation and help to reduce preventable sewer spills. The program has provided a much better picture of the overall condition of the collection system which is over 75 years old in many parts of the District. SD1 took over all of the sewer systems from individual cities in 1996. Many of these sewers had never been inspected or properly maintained.Since SD1 was at the 5-year mark since the inception of CSAP, it was time to assess how the program was doing, to determine if changes should be made, and to utilize the data gathered so far to develop the asset renewal funding needs projection for the next 20 years.The projected asset renewal needs utilized condition data which was in the SCREAM coding format rather than the NASSCO PACP format. The condition scores were used to estimate a remaining useful life (RUL) for each pipe. The RUL for pipes that do not currently have condition data was projected by forecasting the condition based on the distribution of RUL for pipes of the same material that have been inspected. Two renewal rate scenarios were assessed and compared to a typical “rule-of-thumb” 1% per year rate. Under Scenario 1, the average required annual renewal and replacement rate came to 0.92% by total length. Under Scenario 2 the average required renewal and replacement rate came to 0.62% by total lengthThe result is a defensible knowledge-based projection of funding needed to maintain the condition of the collection system at a specified overall condition. In addition, the study showed that the CSAP program has significantly reduced preventable overflows, improved workflow, and has allowed SD1 to move to a proactive mode in the management of its collection system and to provide a higher level of customer service to its customers. Nevertheless some modifications were recommended to help increase efficiency.