Post-Treatment for Quality and Consumer Confidence

Introducing a new water source into an existing distribution system can cause a variety of water quality issues, especially in older distribution systems. The new characteristics can loosen sediments, slough iron or manganese deposits, change water biology, and result in additional changes that effect the taste, odor, or appearance of the distributed water. While these may not have actual health implications, they may result in customer dissatisfaction and a general distrust of the water system. Considering a water treatment plant may be a community’s single largest investment, they rightfully expect an improved water quality. The key to preventing downstream quality issues is proper post treatment of the treated water. In addition, since its difficult to eliminate all distribution system impacts when a new water supply is introduced, an effective consumer education program can minimize consumer complaints while protecting the distribution system and facilitating compliance with water quality regulations. This paper will discuss post treatment requirements for desalination treatment technology typically used in the United States including reverse osmosis [RO], electrodialysis reversal [EDR] and nanofiltration (NF) (considered a variation of RO).