LIMIT AND BENEFIT OF CHLORINE RESIDUALS FOR WATER QUALITY MANAGEMENT IN DRINKING WATER DISTRIBUTION SYSTEMS : WHAT IS THE RIGHT CHLORINE RESIDUAL ?

A synthesis of recent studies carried out at bench,pilot and full scale is presented. Guide lines values from free chlorine concentration to maintain in distribution systems are then proposed. This authors show it is necessary to reduce the main parameters responsible for the chlorine consumption and to implement the tools which allow a real management of chlorine residuals.