Load management on a municipal water treatment plant

Municipal water treatment plants (WTPs) filter and disinfect water. Potable water is transferred by high-lift pump stations (HLPS) to various end users. WTPs are energy intensive with large pumping capacities due to the flow rate and head associated with the distribution of water.Load management (LM) strategies for mine dewatering and water transfer systems exist and have been successfully implemented. It is important to optimise the utilisation of WTPs. A new LM strategy is researched, developed and safely implemented on a municipal WTP. The strategy fully utilises the WTP sub-systems to achieve cost savings. The strategy includes the optimisation of filter backwashing and raw water operations. Optimising these systems realises a cost saving on the high-lift pumps. Operational valves on the filter system were optimised to mitigate algal problems and ensure that the load management is sustainable. An increase in efficiency of 34% for a filter backwash cycle was achieved. Due to filter modifications, the plant is able to supply 5% more water daily. The baseline for LM on the WTP was scaled energy neutral coinciding with the daily water demand. An average evening peak period load shift impact of 2.21 MW was achieved. This results in an annual saving of R 1 million for the municipal water treatment plant, based on 201412015 Eskom electricity tariffs.