Chloramine is now a viable alternative to chlorine as a disinfectant residual in distribution systems with the relaxation of the nitrite standard in the new UK Water Quality Regulations. Chloramine has advantages over chlorine since it does not produce trihalomethanes (THMs) and so the risk of breaching THM standards is negated. It is a more long-lived disinfectant and by permeating the distribution system more effectively, gives better reassurance on water quality received by customers.
Chloraminating water requires careful dosing control at the treatment works. Otherwise, disinfectant residual can be removed altogether or compromised, and tastes and odours can occur. Once in distribution the water chemistry will affect the disinfection power of the chloramine. The project produced an easily accessible, usable, best practice manual for chloramination of drinking water supplies.
Five water utilities supported the study, and Anglian Water contributed to the programme, having extensive operational experience of applying chloramination to surface derived waters and extended distribution systems.
Operators are able to apply chloramination with confidence and the risks of inadequate disinfection and customer complaints if poor practice is adopted will be negated. This will avoid the consequences of poor application i.e. the financial, regulatory and public relations implications.