City council may find continuing to use chlorine in the new water treatment plant hard to swallow after a report presented at the Nov. 5 meeting.
The report includes an increased cost estimate of $13-19 million for removing organics and carcinogenic by-products if chlorine is the secondary disinfection method for the new plant.
A late item on the agenda, city council agreed to look at how the planned water treatment plant will provide secondary disinfection for the community.
The city has a grant of $19 million to construct a new water treatment facility for the city to deal with high levels of manganese in the water. The plant was deemed necessary after changes to federal water quality guidelines came into effect. The city is in the initial stages of the project and at the Nov. 21, 2023 council meeting, council awarded the design phase of the project to Associated Engineering.
Associated Engineering then had to test the water to determine the best water treatment options for three stages of treatment: pre-treatment, filtration and secondary disinfection. A report provided by Jeff Bernardy, senior engineering technologist for the city, explained the process and possible options for the secondary disinfection treatment phase of the project.
Secondary disinfection is the process of injecting a disinfectant into the water throughout the entire system. "Its role is to inactivate any pathogens encountered in the kilometres of pipe owned by the city," explained Bernardy in the report.
This ensures the water meets Interior Health standards and the goal is to have a certain minimum amount throughout all parts of the system to kill potential pathogens.
The two commonly used disinfectants are chlorine and chloramines, with chlorine being used by the majority of the province and many other municipalities around the world. Williams Lake currently uses chlorine in its water disinfection and according to the report "is very quickly consumed by manganese and other natural materials in the water."
However, during the testing process, Associated Engineering found high levels of unforeseen naturally-occurring organic material in the city's drinking water. While the organics do not present health risks on their own, when mixed with high levels of chlorine, they would create carcinogenic (cancer-causing) by-products.
Chloramines are created by combining chlorine with ammonia and can also be used as an effective disinfectant for drinking water.
This option is used in Abbotsford, White Rock and the Capital Regional District, as well as Edmonton, and other parts of the prairies.
While not as powerful initially, the chloramines last longer in the system and do not react with organics, so they do not create regulated carcinogenic by-products, according to the report.
This means the city would have to either control for the carcinogenic by-products or remove them, or switch to using chloramines for secondary disinfection within the water treatment system. Bernardy also reported the use of chlorine is associated with a stronger 'pool' taste and odour compared to the chloramines.
Bernardy's report then put forward three options to go ahead. The first option is to adopt the use of chloramines for secondary disinfection in order to maintain the current grant project budget and schedule. The second is to continue using chlorine but seek additional grant funding to cover the removal of organics, which he said could result in project delays and potentially having to fund the project themselves. A third option is cancelling the project and looking for additional funding at a later date, which would require the city to cover all the costs on the project to date, which have included archaeology work and this design work.
"This council has worked very hard to get this grant, we cannot let $19 million go back to Ottawa and Victoria. It took a long time to get the money," said mayor Surdinerpal Rathor.
Council voted to go ahead on discussions but did not make a definite choice after the full report from the consultant did not come through for information for the council.
"Time is of the essence but it doesn't mean you should be forced into making a decision," said Gary Muraca, the city's chief administrative officer.
Coun. Angie Delainey requested the item become a standing item on the council's agenda in order to keep the community informed throughout the process.
