Adding Value to Sanitary Sewers — An Important Asset of Municipalities

Sanitary sewer rehabilitation programs are generally triggered by the need for reducing infiltration and inflow and restoring structural integrity of a collection system. On the other hand, improving the condition of the components (essentially pipes and manholes) of a wastewater collection system may turn sanitary sewer rehabilitation into a financially beneficial practice in addition to maintaining desired level of service and regulatory compliance. This study discusses a sanitary sewer rehabilitation program being applied on Marco Island, Florida as a case study of proactive wastewater collection system management. The existing system was evaluated using closed-circuit-TV inspection of pipelines and visual inspection of manholes. Accordingly, a rehabilitation program was developed which is based on using trenchless technologies to maximum extent. Depreciation of the system was analyzed for the next 70 years without rehabilitation to estimate the rate of return of rehabilitation. The results indicated the rehabilitation cost is approximately 16 percent of the depreciation that would occur in 70 years in today's dollars.