White Rock to treat water with chloramine
After months of fielding hundreds of complaints from residents about discoloured and malodorous tap water, White Rock is changing the way its water is treated.
City council voted Monday to use chloramine for secondary disinfection of its drinking water instead of chlorine, which is reacting with naturally occurring heavy metals in the water and pipes to produce water that is potable but unpalatable.
“When you’ve got muddy water, nobody wants to drink it,” said Dan Bottrill, White Rock’s chief administrative officer. “It’s a situation that ... wasn’t acceptable.”
White Rock is the only Metro Vancouver municipality with its own water supply, and is served by seven wells that dip into the Sunnyside Uplands Aquifer.
Fraser Health ordered White Rock to implement secondary water treatment after coliform bacteria was found at the Merklin reservoir in 2010.
The company that owned the water utility then, EPCOR, began immediately treating the water at Merklin pumping station with small amounts of chlorine, which mixed with naturally occurring ammonia in the water and resulted in chloramination of the water from that station.
“We’ve had monochloramine in the water utility system since 2010,” said Bottrill.
When the city acquired the utility in 2015, it decided to go ahead with chloramination for the entire system. However, in response to a public outcry about the possible effects of chloramine on health, the environment and infrastructure, council voted in January 2016 to implement chlorination instead of chloramination.
Chloramine has been approved as a disinfection method by Health Canada, the U.S. Environmental Protection Agency and the World Health Organization. A number of municipalities already use it, including Ottawa, Edmonton and Abbotsford-Mission.
Chlorination began Oct. 4, 2016, and soon the city began to receive complaints from residents whose water was discoloured — from a slight brown tinge to the colour of strong tea.
The discoloration resulted from chlorine reacting with naturally occurring manganese in the water and pipes. The city is working on a plan to treat arsenic and manganese in the water supply, and will have a solution in place by 2019.
The city flushed the water mains, but residents’ water continued to be discoloured. In total, the city has received almost 500 complaints. Bottrill said the complaints prompted staff to bring the issue back before council. “We want to make sure water is safe and we want to make sure it is clear,” said Bottrill.
He said the plan is to adjust secondary disinfection at the Oxford pump station by adding a low concentration of ammonia. Chlorine will continue to be added to both the Merklin and Oxford pump stations, resulting in chloramination across the entire water system.
“At the end of the day, it’s fair to say we listened last year and it’s fair to say we listened again,” said Bottrill.
The residents who expressed concern about chloramine last year were surprised to see it on the agenda again.
“Nothing has changed since 2016 when council voted unanimously against it,” Dennis Lypka. “I think what’s really disturbing, too, is the process it went through. It just snuck through there.”
Chloramination will be implemented this week.