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Overflows from sewer pose environmental challenge for Vergennes

VERGENNES — Late in December, the city of Vergennes, as required by the Vermont Agency of Natural Resources in such cases, reported that an estimated 467,000 gallons that its municipal sewer system could not handle had gone through an overflow pipe into Otter Creek.
On Dec. 31 Lake Champlain International Inc. highlighted that overflow on its Facebook page after finding the report in state records: “The State of Vermont legally permitted the City of Vergennes to dump 467,000 gallons of sewage and stormwater into Otter Creek and Lake Champlain on Christmas Eve. Ho ho ho.”
The Vermont Political Observer picked up the LCI report in a colorfully titled post at thevpo.org: “Our Proud Heritage of S*** Dumping.” It detailed several alleged breaches of Vermont’s environmental caretaking.
Those posts found a local echo chamber in social media, including an email chain and the Vergennes Front Porch Forum.
Vergennes City Manager Mel Hawley does not dispute there was a discharge into the creek. Hawley said “between zero and four” such incidents routinely occur every year after periods of heavy rain. And an email he shared from sewer treatment plant operator Rick Chaput showed Chaput’s opinion the system went into overflow at 3:30 p.m. on Christmas Eve and remained there for 36 hours.
But Hawley objected to the online posts’ tone and what he saw as their implications, to the point he said he felt Vergennes had been “thrown under the bus.”
He said the overflow only became public because of the city’s ongoing cooperation with the Vermont Agency of Natural Resources to solve a problem that has plagued the city sewer system since it was built in 1962.
“Any time the Vergennes sewer treatment plant experiences a so-called overflow, we are required to immediately report that to the state of Vermont Agency of Natural Resources and follow that up in writing,” Hawley said.
That problem, he said, is a combination of “infiltration” — ground water getting into the system through older, deteriorating clay pipes or poorly sealed manholes — and “inflow” — water essentially illegally introduced into the system by roof drains or basement sump pumps.
“We suffer from substantial inflow and infiltration,” Hawley said.
In fact, although a complete solution may remain years away, Hawley said Vergennes has done a lot over the decades to upgrade its municipal system to handle the ongoing problem.
In recent years the city increased capacity at the MacDonough Drive pump station, the last link between the larger portion of Vergennes that lies east and north of Otter Creek to the treatment plant on the far bank. It was from that station the overflow ran into Otter Creek.
Now there are two pumps at that station that can each handle 1,000 gallons a minute, a 33 percent increase in its capacity. But when more water and septic waste comes than the pump station can handle, the overflow still goes into the river through a pipe designed to handle it.
One important point, Hawley said, is that he can estimate that the overflow is at the most about 7 percent septic waste and 93 percent water.
He assumes the pumps can routinely handle at least 1,500 gallons a minute. Plant workers have also measured the septic flow during dry spells.
“If it doesn’t rain for two weeks, the amount of flow that is coming into the MacDonough Drive pump station is about 100 gallons a minute,” Hawley said.
Therefore, he said, if there is enough coming at the pumps to create the overflow, at least 1,400 of a minimum of 1,500 gallons is simply water, such as poured from the skies on Dec. 24 and 25.
PROBLEMS
Hawley acknowledged the latest ANR 1272 order is one of many the city has received because of the overflow problem, which is in turn due to infiltration.
“We have been working on this for 52 years,” he said.
Nor is Vergennes unique in dealing with the issue.
“There are municipal treatment plants all over the state and all over the country,” he said. “Unfortunately, that’s the thing that most municipal systems are challenged with. It’s a huge challenge.”
The problem is persistent for several reasons:
•  The city cannot realistically track down every sump pump and roof drain.
•  Many of the 14 miles of city sewer lines are still older clay pipes and remain vulnerable to infiltration.
•  Many problematic pipes lead from the many older homes in Vergennes to the city sewer lines — they are not city-owned.
“It’s very likely the lion’s share of the infiltration is not city mains, it’s private service lines,” Hawley said.
Hawley was asked if city officials would look at some point to the deteriorated private lines.
“I suppose we probably have the authority to force people to upgrade their service lines,” he said. “We’ve been focusing our attention on our own mains.”
EFFORTS
And, Hawley said, Vergennes has taken steps over the years:
•  “Considerably more” than half of the original lines have been replaced.
•  The North Main Street station was improved.
•  The capacity of the plant was increased from 660,000 gallons per day to 750,000 gallons per day in 2001.
•  Knowing that the state-owned Northlands Job Corps property had major infiltration issues, in 2008 the city started billing the state for volume of septic waste at a pump station devoted to Northlands, rather than simply for the number of buildings. After a jump in its sewer bill from roughly $20,000 to $50,000 a year, the state invested “about $750,000 into tightening up their system,” Hawley said. “We don’t have the overflows from Northlands we once did.”
The treatment plant operators also track forecasts and if a major rainstorm is on the way clear as much space in advance in the plant lagoons, which hold up to 4 million gallons.
PERMANENT ANSWER?
This year, Vergennes spent $30,000 to install monitoring equipment in the MacDonough Drive pump station that will allow plant operators to measure the extent of the overflow.
Hawley called that a first step toward a solution.
“We know we have an infiltration problem, but we’ve never known to what degree,” he said. “You’ve got to understand the problem before you can develop a strategy to solve the problem.”
But that equipment did not offer accurate information after the holiday overflow, the first since the equipment was installed late this past spring.
“We have that in place. However, we do not have accurate information,” Hawley said.
According to Chaput’s email, the equipment was still measuring overflow on Dec. 26, after the event had ended. Hawley said the 467,000 gallons is basically a guess, and the total is probably more given the duration of the overflow, although how much more he could not say.
“I think the overflow is way more than 467,000 gallons,” Hawley said.
Chaput said in his email that he was testing the equipment, and Hawley said he was confident that it could be calibrated to start giving good answers.  
“That’s the whole goal. We’ve got to get the overflow monitoring so that it is reading properly so that we know with a lot of confidence that the amount of overflow is X,” he said.
Once that confidence is established, Vergennes will work toward a final answer, Hawley said.
But he could not say how much longer it might take. Asked if it would be decades, he responded, “I would hope not. We keep working, despite Front Porch Forum.”
Well, how long then?
“Right now after multiple 1272 orders we are under a 1272 order that required us to do this overflow system and also to do further investigation. Once we complete that, it will be submitted to the state of Vermont, and we will get another 1272 order relative to the next steps that are required of us,” Hawley said. “I’m not in a position to tell you.”
What Hawley can do is describe in detail the sewer system; its budget health, which has been strong in recent years; and its problems. He will do so at the city council’s Jan. 13 meeting.
“At the next city council meeting, I plan on doing a 20- to 30-minute presentation about our wastewater system,” Hawley said.
Andy Kirkaldy may be reached at [email protected].

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