Microfiltration and Conventional Treatment – Teaching and old dog new tricks! Lessons learned from an integrated Water Supply in Brown County, Texas

Brown County Water Improvement District No. 1 (BCWID) is a wholesale supplier of raw water from Lake Brownwood used for irrigation and treated water used for municipal purposes. To meet increasing demand, an additional 7.5 MGD capacity was identified in 2001. In the summer of 2003, a microfiltration (MF) system was selected for pilot testing to evaluate the feasibility of a membrane treatment system. The pilot test in winter 2003-2004 confirmed that no pre-treatment other than an oxidant was required, and the system was given the highest flux rates approved in Texas (80 gpd/sf). After construction, the design team performed a side-by-side comparison of membrane (7.5 MGD) and a conventional (7.5 MGD) treatment plant expansion, and determined that due to high water quality and reduced chemical costs; BCWID could save $3.6 MM by selecting an integrated membrane treatment plant expansion. The plant has demonstrated a 23% reduced operational cost for the membrane plant since completion when compared to the existing conventional plant.