Evaluating the Latest Low-Pressure Membrane Technologies for the Groundwater Replenishment System

The Orange County Water District (OCWD) operates the Groundwater Replenishment System (GWRS) – a 100 million gallon per day (mgd) advanced wastewater purification facility that consists of three treatment processes: microfiltration (MF), reverse osmosis (RO) and advanced oxidation – all collectively referred to as full advanced treatment. As an integral component of the facility, the low-pressure MF process treats secondary municipal wastewater for subsequent treatment by RO. A variety of low-pressure membrane technologies now exist which afford agencies the opportunity to take advantage of the latest product innovations. Membranes in the GWRS are approaching eight years of service. In addition, the District is exploring the option of expanding the GWRS. As a result, a program was developed to explore and evaluate alternative low-pressure membrane technologies through demonstration testing at the GWRS test facility. Operational data and conceptual retrofit options are reviewed.