(101d) Evaluation of Ceramic Membrane Filtration for the Removal of Dbp Precursors From Surface Water Supplies
The presence of high concentrations of natural organic matter (NOM) in surface water supplies makes many such resources unusable as drinking water resources due to the formation of disinfection byproducts (DBPs) during disinfection of the water for pathogen control. Chlorine, which is an inexpensive and effective oxidant, has been traditionally used for disinfection in a majority of water treatment facilities. The presence of numerous chlorinated compounds that have adverse human health impacts from chlorination, have resulted in new regulations that set maximum limits on total trihalomethane (TTHM) and haloacetic acids (HAA5) in potable waters. Alternative disinfectants such as chloramine, ozone, etc., are being used at some facilities. But, they may have other problems such as growth of nitrifying bacteria in the distribution system, and the lack of disinfectant residual in the distribution system and the potential for recontamination. As such, the removal of DBP precursors from water supplies using membranes has received considerable attention in the last decade. Polymeric membrane filters using microfiltration (MF), ultrafiltration (UF), and nanofiltration (NF) have been studied for the removal of DBP precursors from water suppliers. Nanofiltration, although effective, is expensive to operate. Fouling and flux decline are the major problems with NF membranes. Considerable advances have been made in the manufacture of ceramic membranes (CMFs) in recent years. CMFs are resistant to chemicals, pH variations, can withstand high transmembrane pressures, and provide a robust platform for the removal of contaminants from water supplies and wastewaters. Bench-scale and pilot studies were conducted using 15 kDa to 3 kDa ceramic membrane filters for the removal of DBP precursors from a surface water supply at a Navy installation water treatment facility. The NOM content was analyzed for using measures such as TOC, and trihalomethane potential (THMFP). Size exclusion chromatography was used to characterize the molecular size distribution of the organic matter in the water. The membrane flux, TMP values, and the data for NOM from bench-scale pilot CMF studies will be presented.