Membrane Filtration Regulations and Determination of Log Removal Value

Abstract

A review. The United States Environmental Protection Agency (US EPA) promulgated the Long Term 2 Enhanced Surface Water Treatment Rule, which has identified membrane filtration as a treatment technol. that may be used to achieve the required level of Cryptosporidium treatment. This rule, along with the companion: Stage 2 Disinfectants and Disinfection Byproducts Rule, constitutes the principal US regulations for the application of the membrane technol. in potable water treatment. The primary elements of the regulatory requirements for membrane filtration including the definition of membrane filtration, as well as challenge testing, direct integrity testing, and continuous indirect integrity monitoring, are summarized in this chapter. The requirements and procedure for challenge testing, which is required to demonstrate the ability of the treatment process to remove a specific target organism, are explained in detail. The removal efficiency demonstrated during challenge testing establishes the log removal value (LRV) or removal credit that a membrane process would be eligible to receive. The core requirements of direct integrity testing and continuous indirect integrity monitoring are fully discussed. Design example and case studies are presented. Various water and wastewater physicochem. processes (such as, conventional sand filtration, direct filtration, contact filtration, slow sand filtration, cartridge filtration, diatomaceous earth filtration, dissolved air flotation, sedimentation, lime softening, coagulation, bank filtration, second stage filtration, continuous backwash upflow dual sand filtration, UV, chlorination, chloramination, ozonation, chlorine dioxide oxidn., etc.) are compared with membrane filtration for removal and/or inactivation of Cryptosporidium, Giardia, and virus. [on SciFinder(R)]