Optimizing the potential impact of energy recovery and pipe replacement on leakage reduction in a medium sized district metered area

Abstract

The drive for sustainable societies with more resilient infrastructure networks has catalyzed interest in leakage reduction as a subsequent benefit to energy recovery in water distribution systems. Several researchers have conducted studies and piloted successful energy recovery installations in water distribution systems globally. Challenges remain in the determination of the number, location, and optimal control setting of energy recovery devices. The PERRL 2.0 procedure was developed, employing a genetic algorithm through extended period simulations, to identify and optimize the location and size of hydro-turbine installations for energy recovery. This procedure was applied to the water supply system of the town of Stellenbosch, South Africa. Several suitable locations for pressure reduction, with energy recovery installations between 600 and 800 kWh/day were identified, with the potential to also reduce leakage in the system by 2 to 4%. Coupling the energy recovery installations with a pipe replacement model showed a further reduction in leakage up to a total of above 6% when replacing 10% of the aged pipes within the network. Several solutions were identified on the main supply line and the addition of a basic water balance, to the analysis, was found valuable in preliminarily evaluation and identification of the more sustainable solutions.