AWWA MTC57538

Regulations introduced in 1999 by the Drinking Water Inspectorate (DWI) in England and Wales required Cryptosporidium risk assessments to be carried out at all water treatment works. At sites identified as being "at significant risk", implementation of a rigorous regime of continuous sampling of treated water for Cryptosporidium monitoring was enforced, with a Regulatory standard of 1 oocyst per 10 litres. Exemptions to continuous monitoring were allowed through the installation of approved membrane plant and integrity testing procedures. However, there were uncertainties over Regulatory requirements and how these matched the practicalities of integrity testing procedures that are currently available. The paper reviews the regulatory background to this, and outlines a program of work that was carried out to provide a unified approach to integrity testing that can be used at a site-specific level to help satisfy United Kingdom Regulatory requirements. Includes 2 references, tables, figures.