Sewage bypasses and spills still a factor in Thames River pollution

Thursday, November 5, 2015

by BETTER FARMING STAFF

Earlier this year, the Thames River basin was identified in a Lake Erie Nutrient Targets working group report as one of the culprits causing ballooning phosphorus counts in the shallowest Great Lake.

The report identified the river basin as one where dissolved phosphorus levels needed to be reduced by 40 per cent from 2008 levels. (See ‘Lake Erie agreement confronts Ontario farmers with stiff phosphorus reduction targets,’ Better Farming, November, 2015.)

Agriculture in the basin has been identified as a major contributor to the phosphorus problem, but statistics from the Ontario Ministry of Environment and Climate Change Spills Action Centre suggest there may be other sources, too.

From January 2014 to June 2015, there were 180 sewage bypasses and spills and manure spills reported in the 24 municipalities that are located in the Thames River basin.

Of these, only four manure spills were reported in the watershed; the vast majority (152) were sewage bypasses and of these, London was responsible for roughly two thirds of the total number of bypasses and spills. A bypass occurs when the capacity of sewage treatment systems is overwhelmed, often because of a weather event, and effluent is dumped directly into a watercourse. The effluent may been treated to varying degrees.

Bob Bedggood, chair of the Thames-Sydenham Region Drinking Water Source Protection Committee, describes the total number of bypasses and spills as “high.” But he cautioned about too quickly pointing fingers at any one municipality or group — city or farmer.

Yes, bypasses do happen and it “is a problem and it shouldn’t happen but it will happen because we as a society have not spent enough money on separating the storm sewers from the sewage,” he explained. Doing so is expensive, particularly so for urban centres the size of London or St. Thomas.

Nevertheless, storm sewer separation is also becoming important, he added, because as global warming intensifies, more intense rainfalls occur. “That 100-year event now happens about every 10 years,” Bedggood asserted. And when storm sewers and sewage lines are combined, it “overwhelms sewage treatment.”

London is trying hard to address the problem, added the former farmer. He pointed to the city’s efforts in recent years to improve treatment facilities. Last summer London received approval to embark on a $40 million construction project to add capacity to its largest plant, the Greenway Pollution Control Plant. The plant currently processes 152 Megalitres a day (MLD), said a city environment and engineering services report. The expansion will add the capacity to process 18 MLD and increase the plant’s ability to treat wet weather flows including adding more than seven ML of wet weather flow storage. A megalitre is one million litres.

A spokesperson with the city could not be reached.

Bedggood also expressed skepticism that there were only four manure spills in the region within the same time period. “That’s four reported,” he said. “There’s probably been other spills but they’ve been minor and whoever was involved cleaned it up quickly and it wasn’t a big event.”

A former member of the spills action team in Ontario, he noted that 10 to 15 years ago the team would see roughly 20 reportable manure spills a year in the same area, but would also learn of others that were not as large.

Since then, farmers have become better at managing spills, he said. “I think farmers are more sensitive to that (the impact of a spill) and they’re just trying to do a lot better job, and so we don’t have too many spills now.”

Rob Wrigley, manager of the ministry’s London district office noted that the ministry wants to know about all spills of manure in a watercourse but the onus is on the parties to provide notice. “To say that we do receive notification for every one would not be accurate,” he said. “But we do receive the bulk of calls as required by the legislation.”

Next door to London in Thames Centre, Kelly Elliott, Ward 1 councillor, is delighted her municipality was one of 11 in the river basin that did not record one bypass or spill — sewage or manure — in the 18-month period.

“We really watch our capacity,” she said. “We’re just really conscious on it.” Not only are the municipality’s two treatment plants “fairly new,” but “we’ve done lots of energy upgrades, different upgrades to make sure everything is running well,” she said.

There were no bypasses reported in the municipalities downstream from London, and only three sewage spills because of a dry weather event, noted a spokesman for the provincial ministry. BF

Each year, Better Farming publishes charts on sewage bypasses and spills and manure spills. The report for all of 2014 and the first six months of 2015 is now on our website.