Wastewater reuse through dual-membrane processes: opportunities for sustainable water resources

Numerous pilot plant studies and commercial facilities operating all over the world have demonstrated the technical and economic feasibility of reclaiming municipal wastewater treatment plants (WWTP) effluent through dual-membrane treatment processes. Dual-membrane processes such as continuous microfiltration (CMF) followed by reverse osmosis (RO) are used to produce water that meets all drinking water standards. Pilot plant studies conducted in Gran Canaria (Canary Islands) at the former DEREA Center, treating the effluent from the EDAR del Sureste using CMF followed by RO or electrodialysis reversal (EDR), clearly demonstrated the high quality of the treated water. Commercial facilities producing water for irrigation, for industrial use, to recharge aquifers, or as a source for indirect potable water reuse systems are already operating at these locations: Waster Factory 21, California; West Basin Water District at El Segundo, California; Samsung General Chemicals Co., Ltd., at Daesan, Republic of Korea; Vértesi Power Plant Co., at Oroszlány, Hungary; EDAR de Tías, at Lanzarote, Canary Islands. By the end of 1999 the Scottsdale Water Campus at Scottsdale, Arizona, will produce reclaimed water for irrigation and for indirect potable water reuse. The advanced wastewater treatment (AWT) facility, using CMF and RO, will have a capacity of 38,000 m3/d of product water.

1. Numerous commercial-sized plants are using CMF followed by RO treatment to reclaim WWTP effluents to produce water for irrigation, to recharge aquifers, for industrial use and as a source of potable water. 2. CMF systems have reduced the capital and operating costs of RO systems and allow the use of TFC RO membranes to operate with municipal treated wastewaters and polluted surface waters. 3. Well designed and operated AWT plants with dual-membrane processes, mainly CMF followed by RO, are treating municipal WWTP effluents for “indirect potable water reuse” and to meet all drinking water standards.