The Estes Park Sanitation District Board used its March meeting to review preliminary data from a modeling study being conducted by EnviroSim showing that the wastewater treatment plant is already exceeding stricter effluent discharge standards expected in the future by the Water Quality Control Division’s Clean Water Program, which is under the umbrella of the Colorado Department of Public Health and Environment.
While the U.S. Environmental Protection Agency sets national, technology-based effluent limitations guidelines to regulate wastewater discharge from industrial, commercial, and municipal sources into U.S. surface waters and sewage treatment plants, the state agency regulates local wastewater facilities.
New state regulations were expected in 2023, but that date has been delayed due to permitting backlogs and high compliance costs for small towns. As a result, treatment plants, like the EP San facility, are not sure when the new standards will be set. That uncertainty makes infrastructure planning and budgeting difficult for wastewater utilities.
The computer modeling being conducted by EnviroSim, a firm specializing in treatment plant simulation software that integrates biological, chemical, and physical processes, will help EP San prepare for different scenarios, such as tightening nutrient limits or regulating emerging contaminants.
Paul Jarrett, a project engineer with EnviroSim, attended the March 10 meeting virtually and walked the board through a computer model showing how the EP San plant handles flows and pollutants throughout the year, including the demand during peak summer tourism, and said his firm’s predictions matched lab data so closely that it was “about the best calibration” he has seen.
The results suggest that the sanitation district adapt its operations and strategically plan targeted upgrades over the next decade, and continue to participate in the state’s voluntary incentives program which encourages wastewater facilities to achieve early nutrient reductions of nitrogen and phosphorus beyond current requirements.
By participating in the voluntary program, utilities receive an administrative compliance extension from the Colorado Department of Public Safety, which can help buy time to secure funding for necessary infrastructure upgrades. EP San has been operating on extensions since 2016. Its last one was in 2020.
To plan for the future, EP San is in the early stages of a rate study and is talking with engineers about what capital improvements, such as membrane retrofitting or adding an additional aeration basin, may be necessary for the 61-year-old wastewater plant, which went online in June 1965.
At this time, Jarrett recommended changing the treatment plant’s sludge digester aeration, replacing airlift-recycler pumps with mechanical pumps, and planning a five-stage biological nutrient removal layout process without membranes.
Todd Plummer, chairman of the special district board, was pleased with the technical report. Next steps include finalizing BioWin’s modeling report, rolling out one operational change at a time over the next year, and using those results to shape a plan for additional or more extensive wastewater plant upgrades as needed.
Lauren Benton, a senior project manager with Merrick & Company, an engineering, architecture, surveying, and geospatial firm headquartered in Greenwood Village, Colorado that provides consulting services to sanitation districts, advised E.P. San to begin with incremental changes.
“We don’t want to change everything at once, or it’s hard to track what worked and what didn’t work,” recommended Benton, who attended the meeting virtually.
Food truck plaza concerns
Board members also discussed the district’s sewer and sanitation requirements for the Beetle food truck plaza on Cleave Street, one of the Whimsadoodle Foundation developments. The arts organization has agreed to sign a shared sewer service agreement and pay a tap fee, but because there is no restaurant on site, the organization is not required to install flush toilets and hand-washing sinks.
With a temporary use permit, which the town can renew every 30 days, the Beetle food truck plaza could rely on porta-potties in the long term instead of installing permanent restrooms.
“I don’t think it’s in the public health interest to continue it without proper sanitary facilities there,” Plummer said during the meeting.
Tony Drees, district manager, expressed concern that if the district approves the Beetle’s porta‑potty plan, it could end up having to “police every porta‑potty in town” at other commercial sites that might try to follow the same path.
According to Jennifer Waters, one of the board directors, the district should present the matter to the town’s community development director. Drees agreed to follow up for the town’s response and guidance.
The board also handled routine business, including approving the minutes and financial reports, reviewing cash and receivables, hearing updates on plant and sewer maintenance and GPS mapping, preparing for the annual audit, and continuing to debate whether to auction an aging John Deere excavator through Ritchie Bros. or Roller Auctions.