Real benefits of leak repair and increasing the number of inlets to energy

Two real cases of energy audit were investigated in a district metered area (DMA) of the Metropolitan Waterworks Authority in Bangkok, Thailand. The first case was energy audits before and after leaks were repaired. The repairs resulted in a 9% reduction of inflow to the DMA. We estimated that the input energy to the DMA reduced 8% while the energy in water delivered to customers increased 8%. Thus, two benefits of reducing leakage to energy were found. In the second case, we temporarily opened a boundary valve connecting to the trunk main to function as another inlet to the DMA, so the number of inlets increased to two. The new inlet was nearer to main distribution pipes that delivered water to more customers than the first one. Thus, the inflow from the old inlet decreased to only 10% of the total inflow. The estimated input energy increased slightly by 4% because the inflow and leakage did not reduce, but the energy delivered to customers increased greatly (16%) due to a significant decrease in friction loss. Thus, reducing leakage and selecting the right hydraulic locations of inlets can benefit energy efficiency in DMAs substantially.