Coming Monday A look inside Avery Brewing Co.’s new Gunbarrel brewery. In Monday’s Business Plus.

In a region where beer seems to flow like water, Boulder is weighing a project that could be mutually beneficial to producers of both liquids.

City officials are in preliminary discussions with Boulder-based Avery Brewing Co. to have the local craft brewer supply thousands of gallons of weak wort to the city’s wastewater treatment plant on a weekly basis.

The city would then use the brewing byproduct — which is essentially sugar water — to reduce levels of nitrate nitrogen in the treatment process, said Nick Grossman, a Boulder spokesman.

The estimated cost of the city’s 2015 Nitrogen Upgrades Project is $3 million to $3.5 million, which includes modifications to the existing activated sludge biological nutrient removal basins and the external carbon storage and feed facility capable of storing up to 12,000 gallons of Avery’s liquid waste product, Grossman said.

As part of the project, a 6,000-gallon tank and pump system that may be installed at Avery’s new brewery in Gunbarrel is estimated to cost about $25,000.

Avery Brewing’s new brewery at 4910 Nautilus Court is scheduled to open Feb. 16 at 3 p.m. for dinner service for two weeks and then expanded hours after that time.

Avery Brewing is in its final days of serving beer at 5763 Arapahoe Ave., where it has operated since August 1993.

“We discussed revisiting our timeline with the city once we were fully moved, which looks to be in March now,” Steve Breezley, Avery Brewing’s director of operations, said in an e-mail. “We designed the equipment to divert the weak wort, but the city will be supplying the place to put it — either a tanker on site and/or a holding tank. We haven’t finalized when this would be in place, but both parties are interested in getting it going as quickly as possible.”

The potential arrangement developed as a result of a grant Boulder’s Wastewater Treatment Facility received in 2013.

The Environmental Protection Agency and the Colorado Department of Public Health and Environment awarded the Boulder facility more than $1 million in grant money to reduce nitrogen discharge levels as a means of protecting aquatic wildlife and improving drinking water quality.

As part of the treatment process, liquid wastewater is sent through an activated sludge biological nutrient removal system, during which millions of microorganisms feed on organic materials and other pollutants in the wastewater, Grossman said.

The microorganisms process nitrate nitrogen in a similar manner to how humans process oxygen in their lungs, but only when the organisms have enough carbon on which to feed, he added.

This current microbiological treatment process removes about 50 percent of nitrogen compounds from the community’s wastewater, he said.

To up those levels, city officials needed another source of carbon. However, officials were hesitant to incorporate commonly used materials such as methanol and acetic acid because of potential hazardous effects, Grossman said.

Officials considered other potential biodegradable compounds produced in Boulder — including tofu, whey and pharmaceutical cell media — but none was as effective as weak wort.

A portion of the 2013 grant funds was used to conduct a full-scale trial in which weak wort was evaluated in the reduction of nitrate nitrogen in wastewater.

In early 2014, city officials worked with Avery Brewing Co. to secure 12,000 gallons of the weak wort for a broader testing of the wastewater process. When the microorganisms fed on the weak wort, it resulted in the successful removal of the additional nitrate nitrogen from the wastewater.

“(Using weak wort) is the most sustainable and cost-effective solution that the city’s identified,” Grossman said.

City officials estimate the 2015 Nitrogen Upgrades Project would reduce the nitrogen compounds by an additional 20 to 30 percentage points.

The success of the test triggered a series of informal discussions with Avery Brewing officials about opportunities for a potential future collaboration.

Under the potential agreement, the two parties would contract with liquid haulers to transport the liquid wort in 6,000-gallon loads from Avery Brewing’s Gunbarrel brewery to the wastewater treatment plant 3 miles away off 75th Street.

Using the brewing byproducts could save the city of Boulder money and energy with potential savings being passed along to utilities customers, Grossman said.

Current estimates are that 2,100 gallons of weak wort would result in a $500 daily savings. Avery Brewing would be able to supply that amount twice a week, which would result in estimated annual savings of $52,000.

Grossman did not provide the amount of money the city would pay Avery Brewing, adding those agreements have not been finalized.

At this time, the city has not contacted other breweries, or vice versa.