AWWA MTC57648

Water demands on the Trinity River Authority (TRA) Huntsville Regional Water Supply System (HRWSS) have necessitated an impending plant expansion from 8 to 16 MGD. Membrane technology was evaluated as an alternative to conventional filtration. An on-site pilot was conducted to establish whether membrane filtration is appropriate for treatment of HRWSS settled water and to determine design criteria. Four different membrane systems were piloted at the TRA HRWSS water treatment plant (WTP), including Zenon Zeeweed 1000, Leopold Hydranautics Hydracap, U.S. Filter CMF-S Memcor and Pall Microza. The pilot units successfully managed two plant upsets and over 90 days of pilot operation. While several power outages and numerous breakdowns of pilot unit components slowed progress at the onset of the project, the four different types of membranes were found to be compatible with the clarified water quality at the TRA HRWSS WTP. Average permeate turbidities for all four membrane pilot systems were less than 0.04 NTU. Standard cleaning practices were effective in controlling membrane fouling and maintaining the transmembrane pressure within acceptable ranges. Low-pressure membrane filtration offers several advantages over conventional filtration for the TRA HRWSS WTP. Advantages include but are not limited to: membrane effluent turbidities are consistently less than 0.1 NTU; total organic carbon (TOC) removal is typically improved; and, membranes provide a multiple barrier to pathogens in conjunction with disinfection. This paper addresses the membrane pilot study results as well as the economics and other issues surrounding membrane filtration. Includes tables, figures.