Greg Longman, who next week replaces Brent Manning as the head of the local water authority, says disinfection is paramount after looking into the water quality results in the last two weeks.
Intake water has high levels of E.coli which is an indicator that other pathogens are also present.
Reducing that level will go a long way towards the journey of potable water which meets the requirements and expectations of a developed nation like the Cook Islands, he adds.
“There are different methods but my opinion is with the network and the requirements we’ve got now – bearing in mind there is a legacy of some existing network here which will be adopted – a residual disinfection is required and that’s where I see the method proposed is the most suitable.”
Brent Manning and government both supported chlorination as the most viable and effective disinfection.
But members of the public including anti-chemicals lobby group Te Vai Ora Maori have publicly voiced their concern about the proposed method, asking government to look at other options.
Manning this week maintained that some form of liquid chlorine would be the best permanent disinfection for the water system in Rarotonga.
“Ultimately it’s the government that makes the decision,” he said.
“But my advice would be … a form of liquid chlorine added in a measured dose to kill bacteria and maintain a residual to kill off any bugs that might be introduced into the system.”
Manning said people had different views on disinfection but he hoped “ultimately there is some weight given to people who actually know about these things, the background and operation of the system”.
“In my case I have seen it go wrong in places too in New Zealand, so I know what works and what doesn’t work or what’s not likely going to work.”
To Tatou Vai staff are being trained along those lines and all of them understand the risk the existing water system poses, he said.
“They are mostly local people who were drinking the water before and they didn’t know what was in their water.
“Now they are working and testing on a weekly basis and see what’s in it and they are like they are not going to drink it either.”