Introduction to Disinfection Study Guide

. Chemical and physical relationships govern all disinfection chemistry . Knowledge of these relationships increases operator skills and troubleshooting abilities . Allows operators to control conditions that optimize disinfection practices . Treatment processes are managed to disinfect water for consumption and to meet regulatory objectives . Minimum disinfectant residuals . CT compliance - demonstration of efficient disinfection

Drinking water supplies in Ireland are predominantly sourced from surface waters or groundwaters influenced by surface water. In recent reports on “The Provision and Quality of Drinking Water in Ireland” the Environmental Protection Agency (EPA) found that 81.6% originates from surface water (i.e. rivers and lakes) with the remainder originating from groundwater (10.3%) and springs (8%). Source waters, susceptible to surface contamination, particularly surface waters and groundwater and spring sources contain micro-organisms such as bacteria, viruses and protozoan parasites (e.g. Cryptosporidium) which can present a risk to human health if not effectively treated and disinfected. Since 2008 the EPA has set out as its policy that the most effective means of consistently ensuring the safety of a drinking water supply is through the use of a comprehensive risk assessment and risk management approach that encompasses all steps in water supply from catchment to consumer. The EPA has advised Water Service Authorities to implement the World Health Organisation (WHO) Water Safety Plan approach to risk assessment and risk management.