As the weather gets hotter, residents often raise a stink about smells wafting from local sewage treatment plants — but city officials say major efforts are underway to curb the stench.

At both the Humber and Ashbridges Bay plants in the west and east ends of the city, odour reduction efforts are in motion, according to Frank Quarisa, the director of wastewater treatment at Toronto Water.

The system upgrade project to mitigate smells from the Humber plant has cost to $64 million and wrapped up in late 2018 — meaning this marks the first summer since the changes.

"This includes new process equipment for screening and grit removal and the construction of air handling systems to capture foul air from the process and treat it using three large bio-filters," Quarisa told CBC Toronto in a statement.

Other projects will further improve operations and mitigate smells, he added.

Earlier work conducted at Ashbridges Bay was meant to have a similar impact, including foul air treatment, and is coupled with ongoing projects, Quarisa continued.

However, residents in both neighbourhoods have mixed opinions on whether or not the efforts are working.

'It's just getting worse'

"It's just getting worse, the smell," said Donna Tessier, who has lived near the Humber plant for more than a decade.

"I can smell it coming right in the apartment building ... They need to do a better job," echoed Derryck Furber, a resident of two years.

In contrast, Kurt Monroe, who has lived in the west-end neighbourhood for close to two decades, believes the smell has gotten better through the city's efforts — though he did catch a whiff a "couple times" this summer.

"There was a time, I remember, that it really bothered me," he added. "I had thoughts of really moving from the area — it was that severe. I don't feel that way now."

The number of odour complaints received for the plant has indeed gone down, city numbers show, from six for all of 2016, four for 2017, three for 2018, down to zero so far this year as of July 2.

For Ashbridges in the east, the usual handful of complaints are still coming, with five so far in 2019.

"I've lived in the Beaches almost my entire life so I'm used to the smell of Ashbridges Bay," one Toronto resident posted on a local Reddit community in June.

"But man, when biking past the plant on the Martin Goodman trail, it still stinks!"

Quarisa said both the city and sewage plant staff "continuously work to minimize any and all impacts on the community surrounding the facility and take all odour complaints seriously."

The Humber and Ashbridges plants, he noted, are "large and complex" and "any number of unforeseen events" can impact the sewage treatment process.

If residents do smell something stinky, Quarisa said they can call 311, and staff working 24/7 at the plants can try to solve any issues.