Trials of various technologies have been performed at the Wanneroo GWTP to determine how to enhance the existing treatment regime to prevent the formation of odors in the distribution system. In the last 12 months, enhanced coagulation has been introduced at Wanneroo GWTP, which has reduced but not eliminated downstream DMTS formation
Technologies trialed have included granular activated carbon (GAC), ozone/biological GAC (O3/BGAC), enhanced coagulation, and microfiltration and since 1997, a process based on a magnetised ion exchange resin, the MIEX resin. The treatment objective for these technologies was to reduce the current treated water DOC and non-sulphide-reduced-sulphur (NSRS) levels entering the distribution system. Elevated levels of DOC contribute to biofilm formation in the distribution system, which, in addition to NSRS, is strongly aligned to DMTS formation (Franzmann et al, 1999).