Wastewater system keeps up with expanding breweries
June 18, 2022 | By Lauren Milideo | CorrespondentA drying bed at the wastewater treatment plant. Photo by Lisa Scagliotti
Editor’s note: This is Part II in a series on Waterbury’s wastewater system.
Wastewater is not something most of us think about until something goes wrong. But for the workers of Waterbury’s Edward Farrar Utility District, it’s always front-of-mind, and with Waterbury’s brewery scene expanding, efforts are underway to ensure the town’s wastewater facilities can keep up.
Chief Operator of the district’s Waterbury Wastewater Treatment Plant Peter Krolczyk explained during a recent tour that wastewater from Waterbury village is pumped to the plant, where it enters the first of three large, aerated outdoor lagoons. Over the course of 60 days, as wastewater flows via gravity from the large first lagoon into the second and third lagoon cells, dissolved solids settle out and accumulate on the bottom.
The wastewater treatment plant staff have a sense of humor at the lagoons. The sign says: "Do Not Feed the Alligators. Or go near the water by order of the Village of Waterbury Wastewater Commissioners" Photo by Lisa Scagliotti
Next, the partially treated wastewater is pumped into the building, Krolczyk explained, where more solids and impurities are removed. This takes place via the CoMag System, that uses an iron-magnetite powder that acts as a ballast, causing solids in the wastewater to settle out rapidly as water travels through a series of mixing tanks.
The Waterbury plant was recently honored with an award from the federal Environmental Protection Agency for its efficiency at treating the system’s wastewater and the resulting quality of the water that the plant disburses into the Winooski River and ultimately, into Lake Champlain.
Phosphorus – a major contributor to water quality issues downstream – is removed from the water as remaining solids coagulate and drop to the tanks’ bottom. A large magnet pulls most of the magnetite back out of the solids for reuse in the plant’s treatment process, while the remaining solids can be removed from the treatment system and dried in large outdoor beds.
Some of these solids, which are high in organic content and act as a fertilizer, are spread on fields near the plant, where crops are grown. Another 150 to 170 tons of processed solids leave on trucks annually, headed for Canada, where they are used to fill an abandoned asbestos mine.
The treated water, meanwhile, undergoes testing before it is released into the nearby Winooski River. This testing, Krolczyk noted, ensures that the treated water will not pollute or otherwise harm the river or Lake Champlain into which it eventually flows.
The solids the Waterbury plant produces are known as class B biosolids. That’s an EPA designation indicating that steps have been taken to reduce pathogens. It restricts when various crops can be harvested following biosolid application. The water and biosolids contain PFAS, although the plant does test for levels of five PFAS compounds in these materials. It is worth noting that thousands of PFAS compounds are known to exist, and PFAS chemicals are linked to a number of human health problems.
Locals, tourists, money and waste
Waterbury Wastewater Treatment Plant Chief Operator Pete Krolczyk on a tour of the CoMag system inside the plant. Photo by Lauren Milideo
Vermont is well-known as a craft beer destination, and Waterbury is on that map with two established breweries in town – The Alchemist on Cross Road and Prohibition Pig on Main Street – a third having opened this past winter, freak folk bier on Stowe Street, and a fourth under construction, The Tropic on Foundry Street.
The breweries attract locals, tourists and money – but also produce waste. And the waste that leaves a brewery is not the same as typical household waste, noted Krolczyk.
In addition to standard toilet flushing, handwashing, and other obvious sources of wastewater, breweries produce high-strength organic waste that has a much higher biological oxygen demand than household waste. The U.S. Geological Survey says that’s a measure of how much dissolved oxygen in water is needed for the microbes that break down waste to do their job. The oxygen demand of typical household waste is around 300 mg of dissolved per liter of water, noted Krolczyk. Brewery waste, meanwhile, can reach 30,000 mg per liter.
“As you can see,” Waterbury Public Works Director Bill Woodruff said, “brewery waste has the potential to have a significant impact on the operations of a wastewater treatment facility.”
Edward Farrar Utility District Commissioner Skip Flanders noted that wastewater’s extended residence time moving through the lagoons allows the plant to absorb day-to-day fluctuations in the high-strength waste coming into the plant, and subsequent shifts in the oxygen demand in the lagoons’ water.
“We have an aerated lagoon system that has three cells,” Flanders said, adding that “daily fluctuations in flow don’t cause a problem because they’re all evened out with other days and things, so we can absorb changes in volume and things pretty well.”
High-strength organic waste can have an outsized impact on the wastewater treatment systems it travels through. Wastewater treatment facilities must operate within both a hydraulic capacity and an organic capacity, explained Flanders.
Hydraulic capacity is the daily flow volume of wastewater that a plant can handle, according to Sacramento State University. Organic capacity, on the other hand, is the amount of organic material that the plant can process per day. Whichever category is higher is the capacity the utility district will keep an eye on to remain within the plant’s design/permit limits, Woodruff explained.
The Waterbury plant’s hydraulic capacity is 0.51 million gallons per day, noted Woodruff, and the plant sees about 200,000 gallons of flow a day, so “the treatment plant is not close at all on hydraulic capacity,” Woodruff said.
The plant’s daily oxygen demand capacity is 726 pounds. “If there is a closer parameter it’s the organic capacity, and… some of these breweries, as we’ve talked about, have high-strength waste, which gives us high BOD influent, which gets us closer to reaching capacity at the treatment plant for BOD,” Woodruff said. He stressed in a subsequent email that the plant is well within the limits of its permit in terms of oxygen demand.
Brewery byproducts are not the only high-strength waste making their way through the Waterbury treatment plant, Krolczyk said. For decades, the Waterbury Ben & Jerry’s ice cream factory has produced high-strength organic waste. The organisms that break down the waste at the treatment plant, however, had a hard time processing dairy.
“They didn’t like the Jerry Garcia ice cream,” Krolczyk mused. Today, the Ben & Jerry’s Waterbury factory pretreats its waste to avoid these issues.
Brewers work to sideline high-test waste
The Alchemist co-founder John Kimmich watches as Heady Topper cans are sealed on the production line at the Waterbury cannery. File photo by Gordon Miller
With four breweries soon to be operating in town Woodruff said he expects to see some impact eventually.
“A brewery like The Alchemist, they have a treatment discharge permit from the state of Vermont, so they have limits on what they can send us and they’re operating under a permit due to their size, essentially. They’re large, so you need a state permit to discharge if you represent more than 5% of the organic capacity or more than 5% of the hydraulic capacity of the system to which you are discharging,” he noted.
And, like Ben & Jerry’s, brewers can take steps to treat and divert waste before it reaches the treatment plant. The town’s wastewater workers team with breweries to bring down the oxygen demand of the waste that does go through the plant, Krolczyk said.
A big piece of the puzzle is a practice called side-streaming. That, Woodruff explained, refers to when a brewer “clean[s] down a kettle or what have you, that waste goes to an equalization tank, where it might be pumped off, and taken, hauled away by a waste hauler, as opposed to just using that wash water and sending it right down the drain.”
Side-streaming practices allow breweries to divert the highest-strength waste so it does not strain the local wastewater treatment system.
“Fortunately, this brewery waste, while they’re in high strength, they’re not large volumes, so that helps the whole situation,” noted Flanders. “If they were discharging large volumes of high-strength waste, then it would be much more difficult for the plant to handle it.”
Side-streaming at Waterbury’s largest brewery, The Alchemist, sends its organic waste to Grow Compost, according to Operations Manager Joel Hartman. The Moretown facility last year was acquired by Casella Waste Management, but it has continued its operation with the Waterbury cannery without interruption.
“Casella continues to operate the business utilizing the same truck and driver picking up on the same schedule,” Hartman said. The brewery’s high-strength waste goes to anaerobic digesters around Vermont.
“We continue to hand-collect and side-stream all high-strength waste,” Hartman said. “The BOD concentration of our effluent to the town continues to be in the 1,000-1,200 mg/L range and is well below our permitted maximum.”
Prohibition Pig, too, practices side-streaming. “We side-stream all of our high-strength waste,” said Head Brewer Nate Johnson in an email, “including spent hops from both the boil kettle and fermenter after dry hopping, spent yeast, and fermenter rinses.”
Johnson added that a local farmer picks up the brewery’s spent grain to feed to cattle.
Cattle also receive the spent grain from freak folk bier, noted owner and brewer Ryan Miller – Woodruff’s cattle, in fact. The brewery’s side-streaming practices include diverting high-BOD waste from the drain into totes rented from and picked up by Casella Waste Systems. “This includes kettle debris, spent yeast/wort and first rinse from our [clean-in-place system] tank.”
Miller noted that this was a significant and unexpected expense for the business as they were getting established. He said he wished that “the state would carry more incentives for small businesses that are working hard to mitigate their waste.” Any spent chemical waste that does head for the treatment plant is first diluted and pH-adjusted, Miller said.
But while the process is new, so far it’s working.
“Working with public works has been great though,” Miller said. “We are in good communication with Bill Woodruff. I think we have a good relationship with them, and I hope they’re able to see the effort in which we are trying to keep waste low.”
The grate in the floor at The Tropic, under construction in Waterbury, is a drain leading to a tank that will hold waste to ensure its temperature and pH are appropriate for release to the wastewater stream. Photo by Lauren Milideo
Meanwhile, nearby at The Tropic that’s still under construction, Matt Gordon is setting up the space with side-streaming in mind.
During a recent visit to the location, Gordon pointed out a grate in the floor of the room containing the brewery’s tanks. Particulates or solids can be shipped out from the brewery rather than going into the wastewater system, and first rinse wastewater (which is a high-strength waste material) can be shipped out, he pointed out.
The grate in the floor will lead to a tank where brewers will ensure the wastewater that does go down the drain is an acceptable pH and temperature to be released to the wastewater stream.
“There’s definitely a lot more to it than lots of people give it credit for,” Gordon said.