Ceramic Filter for Small System Drinking Water Treatment: Evaluation of Membrane Pore Size and Importance of Integrity Monitoring

摘要

Ceramic filtration has recently been identified as a promising technology for drinking water treatment in households and smallcommunities. This paper summarizes the results of a pilot-scale study conducted at the U.S. Environmental Protection Agency's (EPA)Test & Evaluation (T&E) Facility in Cincinnati on two ceramic filtration cartridges with pore sizes of 0.05 and 0.01 p,m to evaluate theirability to remove turbidity and microbiological contaminants such as bacteria [Bacillus subtilisp,m) and Escherichia coli μm)], Cryptosporidium oocysts (4-6 μm), polystyrene latex (PSL) beads (2.85 ti,m) (a surrogate for Cryptosporidium), and MS2bacteriophage p.m) (a surrogate for enteric viruses). The results demonstrated that the relatively tighter 0.01-p,m cartridgeperformed better than the 0.05-p.m cartridge in removing all the biological contaminants and surrogates. For turbidity removal, the0.01-μm cartridge performed slightly better than the 0.05-μm cartridge; however, the permeate rate in the 0.01-p,m cartridge reducedrapidly at higher feed water turbidity levels indicating that a tighter membrane should only be used with adequate pretreatment or at a lowfeed water turbidity to prolong membrane life. Microbiological monitoring was identified as a more sensitive indirect integrity monitoringmethod than turbidity and particle count monitoring to ensure effective treatment of water by ceramic filtration. Both PSL beads and B.subtilis showed potential as effective surrogates for Cryptosporidium, with B. subtilis showing higher degree of conservatism. Anyopinions expressed in this article are those of the writer(s) and do not necessarily reflect the official positions and policies of the EPA. Anymention of products or trade names does not constitute recommendation for use by EPA. This document has been reviewed in accordancewith EPA's peer and administrative review policies and approved for publication.