Life Cycle Cost Analysis for Decision Making in Collection System Rehabilitation

Life cycle cost analysis (LCC) is a tool allowing utility owners to make sound project decisions, considering both capital and operating costs over a long-term analysis period. Capital projects prioritized by rigorous LCC analyses facilitate strongly supportable business case decisions. More often performed for projects such as treatment plants or pumping stations, rarely is LCC used to make decisions on collection system rehabilitation. This is unfortunate because rehabilitation projects are consuming a greater percentage of utilities’ capital budgets. This paper presents a detailed description of the LCC methodology as it pertains to collection system rehabilitation decisions. A simple spreadsheet-based case study is presented for collection system rehabilitation of lateral liners using cured in place plastic (CIPP) lining. During the presentation many often overlooked variables influencing life cycle rehabilitation costs will be identified and methods to incorporate them into the LCC will be described. These include not only initial capital and long-term operating costs, but also a broad range of other evidence including job site tests, published reports, manufacturer product data, as well as historical local experience. The broader the range of evidence incorporated into the analysis, the more accurate is the LCC and corresponding business case.