The city of Burlington has launched an investigation after 1.4 million gallons of contaminated stormwater and wastewater were discharged into Lake Champlain during last Friday night’s storm.
Public works officials say it appears the disinfection tank was pumping bleach at too low a rate for a 50-minute period to handle the increased flow from the rain. Although a backup disinfectant kicked in, it was not designed to provide enough bleach to fully disinfect storm runoff.
An on-site wastewater operator was able to fix the problem and disinfect the later storm flow.
Prior to the fix, operators were able to separate out the solids from the mix before it was discharged into the lake a half a mile beyond the breakwater.
Public works officials say that while an alarm notified the operator about low disinfection levels, the “25-year-old disinfection system does not have tank level sensors or alarms that could have shortened the time it took to troubleshoot this issue.”
Because of the potential for increased bacteria levels, signs were posted at Blanchard Beach, Blodgett Access Area, Oakledge and Perkins Pier for 48 hours after the incident to caution would-be swimmers and paddlers against entering the lake.
“Beaches should never be closed in Burlington, but unlike a generation ago they are no longer closed for days, weeks or seasons at a time,” says a prepared statement from the city’s Department of Public Works. “We will continue this generation’s stewardship and progress in advancing water quality.”
Burlington’s wastewater treatment plant has been plagued with equipment problems for years. High profile malfunctions in 2018 prompted Queen City residents to approve $30 million in wastewater and stormwater upgrades.
Burlington is also one of the 14 towns and cities around Vermont that have combined sewer systems that treat both wastewater and stormwater.
While those systems have the benefit of treating stormwater, which contains pollutants like road salts and pesticides, they also were not designed to handle intense bursts of rain linked to climate change. During storms, cities like Rutland, Burlington and Montpelier routinely dump large volumes of untreated combined stormwater and water — instances called “combined sewer overflows” — at outfall points to keep from overwhelming their aging systems.
While required by the federal Environmental Protection Agency to eliminate combined sewer overflows, municipal wastewater operators caution that building systems big enough to handle stormwater flows from the biggest storms would be hugely expensive.
Members of the public can sign up for alerts about unpermitted wastewater discharges through the Vermont Department of Environmental Conservation.
