Chlorine concerns dismissed

Busselton Water Board has dismissed concerns switching to chlorination could expose residents to harmful microorganisms protected by ultraviolet disinfection systems.

The Board announced in 2010 they would implement full-time chlorination of Busselton’s water to protect the growing network against infection from the harmful microorganism naegleria fowleri.

Queensland water expert Ben Kele told the Times he believed the change could leave residents exposed to other harmful protozoa such as giardia and cryptosporidium.

Mr Kele, who is completing a PhD on wastewater treatment at Central Queensland University, said chlorine was ineffective against giardia and cryptosporidum, which were typically controlled by UV systems.

“The water authority is looking at stopping one disinfection process and bringing in another disinfection process but in doing so they’re opening the door to other protozoa,” he said.

Mr Kele said the threat of giardia and cryptosporidum caused the 1998 Sydney water crisis and infection could result in severe gastroenteritis.

However, Busselton Water Board chief executive Keith White said a risk assessmentshowed the risk of contamination was low.

“Busselton Water’s drinking water risk assessment showed protozoans present a negligible hazard in the pristine source waters. Thus, the public can be assured of a low risk to public health from this source of contamination,” he said.

Mr Kele said it was “a bit unusual” to replace a UV system with chlorination and Europe was now avoiding chlorine by using advanced UV technology and multi-barrier systems.

“Chlorine is the old technology. There are other chemical disinfection systems such as chlorine dioxide that have minimum taste effects, minimum chemical by-products and can be used in a multiple barrier approach,” he said.

Mr White maintained the risk assessment showed naegleria could only be controlled through the use of chlorine to disinfect the source water and maintain residuals in the distribution system.

“In line with the recommendations from the Australian Drinking Water Guidelines, chlorine was then selected by Busselton Water as the most effective, practical and costeffective means of disinfection,” he said.

Mr White said chlorine dioxide was not widely used in Australia because of the need for on-site preparation of the disinfectant, possible generation of by-products and operational safety and health concerns.