Halifax Water will turn off its ultraviolet disinfection system Tuesday as part of a two-month pilot program expected to lead to cost savings but also elevated levels of bacteria in the harbour.
Environmentalists and the union representing the utility’s workers have sounded the alarm bells over the potential long-term effects of the project.
The final stage of the wastewater treatment process uses ultraviolet lights to disinfect the water, eliminating the bacteria’s ability to reproduce.
The program, known as seasonal disinfection because it will run from March 1 to April 30, means that wastewater treatment facilities in Halifax, Dartmouth, Eastern Passage and Herring Cove will have their UV systems turned off Tuesday.
“All the other systems will completely remain operating, so folks won’t notice any difference in the clarity of the water, there will be no change in the smell of the water,” said Halifax Water spokesman James Campbell.
When Halifax Water first proposed the program last year, it had asked for it to run from Nov. 1 to March 31.
However, the provincial Environment Department issued an approval Wednesday for a two-month pilot program, and will determine later if the longer period is viable.
The utility estimates that if the program were to run a full year, it will save $148,000 and cut down on greenhouse gas emissions by 1,100 tonnes, and reduce energy consumption by more than 1.5 million kilowatt hours - equivalent to the annual usage of approximately 157 average Nova Scotian households.
“A lot of people on private wells have a UV disinfection system on their private wells, and UV light uses an enormous amount of electricity,” Campbell said.
Those cost savings will go toward upgrading their systems, he added.
“If we can shut them down completely and do a major overhaul, it just makes it much easier and quicker and better.”
But John McCracken, a spokesman for CUPE Atlantic, which represents Halifax Water workers, has raised concerns about the project.
“We’re always concerned when they cut back on any services, and this will be no exception,” McCracken said. “We don’t really quite understand why they’re doing this now, why the change, other than the fact that they’re obviously looking at cost savings.”
Similar programs are run in other provinces, including New Brunswick, Quebec, Ontario, Saskatchewan and British Columbia.
Part of the rationale around seasonal disinfection is that there is less of a need for ultraviolet treatment of wastewater effluent in colder water that is not being used for recreational use.
“Well, not necessarily,” McCracken said, referring to the mild temperatures so far this year. “From last winter to this winter, we’ve had a dramatic change in the weather.
“For us, the safer the better. I mean, that’s the bottom line.”
Jocelyne Rankin, water co-ordinator at the Ecology Action Centre, was unavailable for comment Friday.
But in a letter she sent to Campbell last year, she noted that Halifax Harbour is a living ecosystem, with a diverse array of species, and is used recreationally year-round by surfers, scuba-divers, boaters and fishermen.
Health, ecosystem concerns
“Seasonal disinfection makes all of these activities more difficult and potentially dangerous to health,” she wrote.
“The EAC believes that the significant investments made to clean up the harbour should not be put back into question, especially by weighing clean water against financial savings.”
She said seasonal disinfection will cause bacteria levels to rise to more than 1,000 colony forming units per 100 millilitres, “compromising marine life and biodiversity in the harbour.”
In preparing for the pilot program, Halifax Water began taking water samples in October to get baseline data on the water quality.
At that time, levels of fecal coliform, E.coli, and enterococcus were well below what is considered safe for swimming.
Once the utility turns off the UV system next week, it will begin taking additional samples to see how high the bacteria levels get.
“We’ll see where the numbers go, but we certainly anticipate that the bacteria levels will rise, for sure,” Campbell said.
Once the UV lights are turned on, it will take two to three days for bacteria levels in the harbour to return to safe swimming levels, Campbell said.
But that comes as little consolation for McCracken.
“I think people need to pay very close attention to this. We’ve had problems (with water quality) in the harbour, as you know, and we just think this is moving in the wrong direction,” he said.