Ozone enhanced ceramic membrane filtration for wastewater recycling

Abstract

Abstract The Water Corporation of Western Australia uses polymeric ultrafiltration (UF) membranes across a range of applications including surface waters with high natural organic matter (NOM), recycling of secondary treated wastewater and pre-treatment for seawater reverse osmosis (SWRO). These challenging raw water conditions require expensive chemical dosing and clean-in-place (CIP) regimes, high frequency of membrane replacement and reduced membrane life. The greater durability of ceramic membranes, with optimal ozone and coagulant dosing, offer a potential capital and operating advantage over polymeric UF membranes. The Water Corporation collaborated with PWN Technologies (PWNT) to establish a ceramic membrane pilot plant at the Beenyup Wastewater Treatment Plant (WWTP). Optimised performance of the pilot plant was established and compared with existing UF membranes treating secondary treated wastewater prior to reverse osmosis (RO) in an indirect potable wastewater recycling application. Findings show a sustainable flux rate of 150 L/m2/h is achievable with ceramic MF membranes while filtering secondary treated wastewater. Higher flux rates up to 250 L/m2/h have been tested and are possibly sustainable, however, other bottlenecks in the pilot plant (ozone generator capacity) prevented longer test runs at this flux. Comparable design flux rates for polymeric UF membranes are 50 L/m2/h.