Wastewater Collection System Optimization for Cost-Effective and Sustainable Capital Improvement Planning

One of the greatest challenges facing water utilities when developing wastewater planning strategies is to find solutions that are not only cost effective in the short term but that also provide the desired level of service over the life of the infrastructure. Uncertainties in future population forecasts, climate change impacts, rates of system deterioration and accuracy of hydraulic model calibration can have a significant impact on planning solutions. A powerful new decision-support approach is now being used to evaluate wastewater collection system improvement alternatives and select cost effective inflow and infiltration (I/I) reduction targets. This planning approach assists wastewater management professionals in developing capital improvement plans which meet affordability constraints while maintaining sufficient flexibility to accommodate future uncertainties. This paper describes the application of genetic algorithm (GA) optimization to collection system master planning and gives an overview of how it has been used by Johnson County Wastewater (JCW) since 2007 for planning upgrades to the Turkey Creek wastewater collection system in Kansas, USA.