Burlington exploring wastewater treatment upgrades

BURLINGTON, Vt. (WCAX) - A primary culprit behind harmful cyanobacteria blooms in Lake Champlain is phosphorous from agriculture, stormwater, wastewater, and other sources. Now, the city of Burlington is taking further steps to reduce its contributions of phosphorous going into the lake.

Burlington’s wastewater treatment plant currently extracts 95% of the phosphorous it treats. And for the last month, they have been doing trial runs with three different companies to see how much more of that last five percent they can tackle.

The statewide push to prevent as much phosphorous as possible from heading into the waterways prompted the city of Burlington to explore options for further filtering of wastewater. Burlington needs to filter around 1,100 pounds of phosphorous a year under the Lake Champlain cleanup plan.

“If our calculations are correct and these technologies perform as well as they have performed at other locations, we estimate that we would get about 2,300 lbs. of phosphorous removed, which exceeds that average that we need to hit,” said Megan Moir with Burlington Water Resources.

Three companies over the past month have worked at the main wastewater treatment plant using different methods to see which performs best. The city is expected to present the results of their in the coming weeks.

“These technologies -- through a variety of means -- get out that last little bit. They can’t get out all of it because there’s always a small portion that won’t react with any chemicals or any process you throw at it but they are getting out as much as is technologically possible at this time,” Moir said.

Based on the results, the city will design a new tertiary filtration system that voters will have to sign off on. The price to rehab the existing systems and add new technology is expected to run in the millions.

Current cyanobacteria blooms, especially in shallow bays, are linked to legacy phosphorous that’s embedded in the lake. But the Lake Champlain Committee says communities, agriculture, and wastewater systems need to work together to protect the future of the lake.

“We can’t expect to see an immediate response from these improvements, but if we don’t take these steps further down the road, we are certainly going to see an increased negative impact from not having acted,” said the committee’s Lori Fisher.

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