More than 120 residents of Osoyoos, B.C., have signed a petition asking council to do something about the "disgusting" smell of sewage in town.

City staff say it's because the sewage system can't handle the sharp increase in population when tourists come to the south Okanagan town in the summer.

The smell, which comes from the sewage lagoons, has been especially prominent the past few months, stinking out a nearby golf course and surrounding neighbourhoods.

"The awful smell definitely has increased the last couple of years. It makes it sometimes impossible, unbearable to sit outside on a summer evening and have dinner," resident Sandra Hashey told council at the town's committee of the whole meeting on Tuesday.

"We can't leave our windows open at night because the smell is so intense and we are just fed up and we just want to know if the town has something planned."

The scent coming from the sewage lagoons near the Osoyoos Golf Club is described by some locals as 'unbearable' during the summer months. (Google Maps)

Mayor Sue McKortoff said council is well aware of the odour.

"It consumes all of us on a daily basis at town hall," she said.

"I'm horrified at what has happened this summer because I think it's been worse ... certainly than last year," McKortoff added.

Summer loads

There are several factors contributing to the smell, said Jared Brounstein, director of operational services in Osoyoos.

The biggest is that the sewage system was designed for 20,000 people. Outside the summer months, it typically has 5,000 people using it.

"What happens is in the summer the loads go through the roof and that causes additional flow in the system, and, unfortunately, our system is not designed to keep up with it instantaneously," said Brounstein.

The smell starts to dissipate at the end of the summer as tourism slows down.

Adding to the problem is that many of the sewage stations see very little flow during the year, so sewage sits in them until enough accumulates for it to pump to the next station. By the time the sewage reaches the main station, it's "extra rank, extra smelly," said Brounstein.

This "extra rank" sewage eventually goes through the main lift, or pump, and into the lagoons where it is aerated and releases the smell even more.

It's unknown why the smell is worse some years than others.

In April, council approved a new $4.6 million lift station that it hopes will help alleviate the smell.

Next week, council will also discuss the use of a potential additive called Acti-Zyme to see if that could help.

"We certainly understand the concerns and I can promise you that we will try our best to solve this problem," said Mayor McKortoff. "Because I get it, we hear from you all the time."