AWWA MTC64498

This paper compares the regulatory philosophy underlying the more rigorous Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) requirements with not only the regulations governing conventional filtration under other U.S. Environmental Protection Agency (USEPA) water treatment rules promulgated in the past 20 years, but also to previous USEPA guidance dealing with alternate filtration technologies under the 1989 Surface Water Treatment Rule (SWTR), the rubric under which membrane filtration has been regulated in the absence of technology-specific requirements that may be established by state primacy agencies. In addition, the most common arguments both for and against holding membrane filtration to a more rigorous regulatory standard than media filtration (as a component of conventional treatment) are presented. Note that for the purposes of this paper, membrane filtration refers to microfiltration (MF) and ultrafiltration (UF) technologies. Although the LT2ESWTR and associated Membrane Filtration Guidance Manual (MFGM) include nanofiltration (NF) and reverse osmosis (RO) under the definition of membrane filtration as technologies that are capable of removing pathogens in compliance with the rule, unlike MF/UF. These desalination processes are not designed for solids removal. Therefore, this discussion is limited to the use of MF and UF, which are generally utilized in applications analogous to those for which media filtration is employed. Includes 6 references, tables.