AWWA MTC61201

Many noncommunity surface water supplies throughout the United States currently utilize bag filtration to comply with the filtration requirements of the Surface Water Treatment Rule (SWTR). It is difficult, however, for bag filtration technologies to meet the Cryptosporidium removal requirements of the Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR). The Minnesota Department of Health (MDH) is therefore conducting an ongoing study on filtration technology alternatives for small systems. The operational performance of several membrane technologies is being evaluated through pilot testing. Factors such as flux, frequency of chemical cleaning, fouling rate, pretreatment requirements and operational complexity are used in the membrane comparison. Particle counts and turbidity are also used to gauge performance, although it is expected that all systems will exceed required removal efficiencies. Various classifications (microfiltration, ultrafiltration, nanofiltration and reverse osmosis) and configurations (crossflow and dead-end) of membranes are represented. Membranes are chosen based on filtration performance, system capital cost, operational simplicity/cost, and availability. Study results thus far suggest that membrane filtration offers a viable means for noncommunity systems to comply with existing and future US Environmental Protection Agency (USEPA) drinking water regulations. Includes 6 references, tables, figures.