Improving Performance and Reducing Costs in Reclaiming Secondary Municipal Waste

Abstract

The Orange County Water District of Southern California conducted side-by-side testing of the latest reverse osmosis (RO) membrane technology and membranes currently operating in the district's Groundwater Replenishment System. The new RO elements were installed in a satellite vessel attached to the first stage of an existing three-stage train. New membrane performance was monitored for seven months and compared with the performance of the existing membranes, which had been operating for two years. Construction of the new elements included a thicker (34-mil) spacer, leading to less differential pressure loss and less fouling potential. The new elements had the same membrane area as the existing elements and, therefore, could be operated at the same flux and flow. This article compares operating data to demonstrate the new membrane's improved performance, RO membrane chemistry, and element design. The data demonstrate the new membrane's potential for reducing operating costs in a full-scale system.