$57 million upgrade to Avon’s wastewater treatment facility ushers in a new era for water district
Members of the public tour the facility on July 24 after construction was completed in September
Eagle River Water & Sanitation District/Courtesy photo
When the Avon Wastewater Treatment Facility was built in 1969, Avon looked a little different. There was no Harry A. Nottingham Park, and no Nottingham Lake neighboring the facility, but people living between West Vail and Avon needed their wastewater processed.
Every decade or two, the plant received upgrades to keep operations current.
In September, the latest update to the facility, a $57 million, five-year nutrient upgrades project, was completed. The result is a plant that looks, feels and runs very differently.
The Eagle River Water & Sanitation District invited members of the public to tour the updated Avon Wastewater Treatment Facility on Wednesday, July 24.
The $57 million project is “the largest project the district has done, to date,” said Dick Cleveland, district board chair, to those gathered to tour the plant. “Things like this are absolutely imperative for keeping the river clean, and the water safe.”
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What does a wastewater treatment facility do?
“We take a lot of pride in being wastewater operators,” said Tim Drescher, supervisor of the Avon Wastewater Treatment Facility. “You’re part of a system that’s taking in this extremely polluted water, and you’re putting it back into the river … oftentimes cleaner than the water that’s in the river in the first place.”
Wastewater treatment facilities take in wastewater — the water that goes down drains, from toilets, showers and the like — and clean it so the water can be released back into the river, and the solids removed.
The Avon facility can process up to 4.3 million gallons of water per day, the most of the district’s three plants. On average, the Avon plant processes about 1.7 to 1.8 million gallons per day, with spikes around the holidays.
“There are two main byproducts of wastewater treatment. One is clean water going out into the river. The other is biosolids, which are typically really rich in nitrogen and phosphorous, and can be used as a fertilizer,” Drescher said.
Wastewater goes through seven main types of treatment processes between when it arrives at the plant as raw wastewater and when it is released back into the river as clean, clarified effluent, or flow returned to the river.
“99% of what comes into a wastewater plant is just water,” Drescher said. Most of that water is returned right back to the Eagle River.
The water released by the plant is “sometimes even cleaner than the water in the river itself,” Drescher said.
Solid waste is removed from the wastewater at the Avon plant and processed at the Edwards Wastewater Treatment Facility, where it is turned into biosolids that can be used by the public.
Much of the cleaning of the water is done by naturally occurring bacteria and microorganisms, or bugs.
“Wastewater treatment, we’re just big bug farmers,” Drescher said. “We’re trying to create an environment where bacteria and microorganisms can thrive and oxidize any incoming waste.”
“We take a lot of pride in not using chemicals; we like to use the natural biological tools that are in place already to be able to treat (wastewater),” Drescher said. “We’re doing what nature can do, but on an industrial scale.”
The Avon facility uses just one chemical, a glycerin-based byproduct of the biodiesel manufacturing industry that is both non-hazardous and reusable.
“It’s an extra carbon source for our phosphorus-accumulating organisms and our de-nitrifying organisms,” Drescher said.
Odors at the Avon plant are controlled through two towers filled with granular activated carbon. Odors bind to the carbon, neutralizing the scent. The towers were installed early on in the project.
“Since we got these in, we have received zero offsite odor complaints that can be credited back to wastewater,” Drescher said.
Why take on this project?
In 2012, the Colorado Department of Public Health and the Environment passed Regulation 85, which requires all wastewater treatment plants processing over 2 million gallons of water per day to limit the amount of nitrogen and phosphorus they release in their effluent.
“These are (in) things that we all flush down our drains, whether it’s urine, fecal matter, soaps, detergents,” said Siri Roman, general manager for the district.
Too much nitrogen and phosphorous in rivers and lakes can speed algae growth, limiting the oxygen that fish and other aquatic life need to survive.
Additionally, certain older parts of the plant needed upgrades.
“There was a need for a lot of capital replacement due to aging infrastructure and equipment that was past its useful life,” Drescher said. “That was determined in design, or pre-design.”
The plant continued to run during construction
The project took five years of planning, design and construction.
“A really incredible amount of thought went into this project, to make sure we were spending our rate payers’ money efficiently and effectively, setting us up for the future, so that 50 years from now, this plant can still operate,” Roman said.
Construction took 41 months from groundbreaking to completion, finishing on Sept. 30.
The plant had to continue to operate during construction, processing millions of gallons of wastewater per day from households and businesses between West Vail and Avon.
“Wastewater treatment, we’re just big bug farmers. We’re trying to create an environment where bacteria and microorganisms can thrive and oxidize any incoming waste.”
— Tim Drescher, supervisor of the Avon Wastewater Treatment Facility
“We can’t just shut down a wastewater plant while we’re doing construction,” Drescher said. “We can’t just say, ‘stop flushing toilets, stop taking showers.'”
Keeping the plant running during construction involved “a lot of planning and preparation, both between district staff, our engineer and our contractor,” Drescher said. District staff analyzed the construction plan to come up with methods of procedure to keep the plant fully operational. “It was a very collaborative process.”
Results of the nutrient upgrades project
“We essentially went from one era of technology in biological nutrient removal to a more sophisticated, contemporary, and relevant era of biological nutrient removal,” Drescher said. “In order to do that, you have to reconfigure your biological process, and that involves internal construction to your wastewater treatment process.”
The main nutrient-related upgrades occurred on the plant’s aeration basins, to cultivate different characteristics to encourage the growth of different types of microorganisms and bacteria that convert waste into different forms.
“Since the upgrades were completed, effluent concentrations of total inorganic nitrogen have been reduced by 43% and total phosphorus by 93%,” according to the handout the district provided to those taking the tour.
Operator access and control over the plant, especially the aeration basins, also improved. While formerly, operators could only access the aeration basins through two-by-three-foot windows, now operators can comfortably walk above the basins to take samples and examine their performance.
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“Prior to the construction project, operator access was super limited, we could only see certain parts of our process, but now we can essentially see all of it and have a much greater understanding and appreciation for it, and be able to react quickly because we can actually see what’s going on,” Drescher said.
The plant’s aeration capacity was also increased from 1.2 million gallons to 1.8 million gallons to prepare for population growth in the valley.
To pay for the project, the district took on bonds, or loans similar to a mortgage. To pay back the bonds, wastewater rates increased for ratepayers this year. On average, the cost to ratepayers from the project is $9.04 per single-family equivalent, or 3,000 square feet of home, per month.
