Energy Recovery Devices, Membrane Flux Balancing and Net Energy Consumption For Recycled Water – A Full Scale Evaluation

At the Orange County Water Districts Groundwater Replenishment System, 6 – 5 mgd Reverse Osmosis units have been recently installed to provide an additional 30 mgd of treatment capacity. The units are configured in a 77:49:24 array with an Energy Recovery Device located between the first and second stage. The system was also designed with a bypass around the array to facilitate operations and maintenance. Concentrate from the third stage is used to drive the turbine and recovery energy. The configuration of the system provides the ability to operate RO units with/without the ERD in order to compare energy consumption and membrane fouling characteristics over an extended period of time in a side by side manner. The results of the evaluation will be presented.