Small pipe creating raw sewage risk

Westside treatment plant unable to meet peak flow, needs $3.5M upgrade

A pipe that discharges treated sewage into Okanagan Lake should be replaced even though costs have jumped from $2.8 million to $3.5 million, regional officials say.

The existing pipe from the Westside sewage treatment plant is failing and unable to handle peak flows, raising the prospect of a messy back-up.

“There is urgency for this project to proceed at this time,” reads part of a staff report that was going to be considered Monday night by directors of the Central Okanagan Regional District.

Testing has shown the existing pipe can only carry a maximum flow of treated sewage of 170 litres per second, or 25 per cent below its original capacity.

But flows do exceed that limit, sometimes going as high as 300 litres per second, for durations as short as a few seconds and as long as two hours.

“When this occurs, excess flows start to back the system up and staff utilize empty clarifying tanks as temporary storage until flows recede below 170 litres per second,” the report states.

Raw sewage is also occasionally held in upstream trunk mains. “From a risk management perspective, this is not the way to operate a sophisticated liquid waste management plant,” the report says.

Four companies bid on the outfall expansion project. Staff was to recommend the low bidder, Kelsey Pipelines Ltd., of Saskatoon, be awarded the contract.

Regional staff say many Okanagan municipalities are seeing bids come in for various infrastructure projects that are significantly higher than expected, in the range of 25 to 40 per cent.

“This trend has been ramping up for most of 2017 and is expected to continue for the next two to three years,” the report says.