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Chevron says sewer a potential source of slow oil leak at its Burnaby refinery
A leaking pipe could be contributing to the leak of an oily substance from the Chevron refinery in North Burnaby.
Last April, the substance—a mixture of mostly water with gasoline, diesel and traces of crude oil—was discovered in the refinery's perimeter groundwater monitoring wells, in a ditch next to a railway right-of-way, and along the foreshore of Burrard Inlet below the refinery.
The company's continuing investigation recently found a leak in a concrete pipe in its internal sewer system, near test wells that found elevated levels of contaminated groundwater. The internal sewer system takes water contaminated during the refinery process to an on-site treatment plant before it's discharged into the city sewer system.
"This could be a contributing source to this issue, however, it's really not fair to call it the definitive or the source," said Ray Lord, Chevron Canada's manager of public affairs. "There could be others and we may never find a single source. It's a big complicated facility."
The pipe has been in place for several decades and will need to be bypassed before it is repaired or replaced, a process that could take a few months.
It's believed the hydrocarbons seeping offsite is due to the fact the refinery is over 50 years old and over the years petroleum products have soaked into soils and eventually made their way into groundwater on the site.
Since last August, a series of extraction wells have been installed along the refinery's fence line, from which potentially contaminated groundwater is pumped out for treatment daily.
"We're dealing with a very long term situation, it's not going to be a very quick remediation thing, it could be going on for years," cautioned Lord. "These things happen very slowly. The best we cam do is reduce the amount of current material entering the system and extract what we can and prevent anything from leaving our property. That's the fundamental strategy."
Meanwhile, the soaker pads used daily for spot cleanups along the foreshore are currently being replaced with special oleophilic mats which can stay in place for up to two years.
Lord said the specially-engineered material, a proven technology used in similar situations around North America, absorbs hydrocarbons but not water. They should be in place by mid-March and will be checked regularly.
On the beach, 50 to 100 ml, or a few Tablespoons, of hydrocarbons have been picked up daily. A total of 16 litres have been observed as of early December, Lord said. As of last November, 800 litres had been recovered from an extraction well in the railroad ditch. And from early August to December, the extraction wells removed about 10,000 litres of hydrocarbons.
"The extraction wells are working quite efficiently and over time our expectation is that we'll see those numbers decrease especially if we can isolate and identify any contributing sources."