Putting waste to use: At Wasatch Resource Recovery, the inevitable detritus of our culture does not rot in vain

By Mary McIntyre

Situated on a piece of land in North Salt Lake, abutted by a field of grazing cows, is a new player in the Zero Waste arena: Wasatch Resource Recovery. A public/ private venture with a 50/50 partnership between the South Davis Sewer District and Alpro Energy, Wasatch Resource Recovery (WRR) is the first anaerobic digester in the  Mountain West to collect food waste.

While an anaerobic digester may sound like a science experiment gone awry, it’s actually an innovative way to divert food waste from the landfill. It is also rated #30 on the Drawdown Project’s list of top 100  practices that can reverse global warming.

We have a huge problem in our country with food waste, with estimates that 40% of food produced in the United States is wasted, along with the inevitable . Rotting food waste in landfills releases methane, a powerful greenhouse gas that is up to 84 times more potent the carbon dioxide (CO2). By diverting food waste from our local landfills to the anaerobic digester, WRR will be helping to reduce the amount of greenhouse gasses emitted into our local airshed.

WRR estimates that processing the food waste in the anaerobic digester will be equivalent to taking about 50,000 cars off of the road each year. The life of our landfills also gets extended by keeping food waste out.

So, what is anaerobic digestion and how does it work?

Anaerobic digestion is the natural process in which microorganisms break down organic materials made of plants or animals in a closed space where there is no air (oxygen). WRR has contracted with local waste haulers, like Momentum Recycling, and participants, like Park City Mountain, Harmons, Publik Coffee Roasters, Swire Coca-Cola and many other businesses, to collect food waste and bring it to WRR for processing. It’s a multi-step process that will take the food waste and turn it into usable products like biogas (a renewable energy) and bio-based fertilizer pellets.

1:   Organic waste is separated

Businesses collect their source-separated organic waste in designated collection containers on-site. (WRR will accept food waste that is packaged or bagged.)

2:   Collection and delivery

Organic waste is collected by a waste hauler and transported to WRR in North Salt Lake.

3:   Pre-processing and de-packaging

Organic waste is processed by a series of machines that will remove any non-organic contaminants. Then the organic waste enters a grinder, where it’s chopped into small bits. Secondary water (non-potable) is added to the ground-up organic waste and mixed until it becomes liquified. As the organic liquid is fed into the digester, it’s passed through a rotating screen to ensure that any remaining contaminants or packaging bits are removed.

4:   Digest

Once the organic waste reaches the digester —there are two onsite now, each with a 2.5 million gallon capacity—it’s heated to accelerate the growth of microbes. It’s the microbes that will break down the organic waste, resulting in biogas production.

Eventually, as volumes grow and the digesters reach full capacity, the biogas will be captured and purified before being converted into renewable natural gas (biomethane) and fed into a nearby pipeline. When the WRR plant is fully operational, it will provide natural gas for about 40,000 people, or 15,000 homes.

Imagine cleaning out your refrigerator and instead of tossing the food waste into the garbage bin, you put it into your backyard composter. In effect, that’s what WRR is doing on a massive scale for businesses along the Wasatch Front and Back. There are no limitations on what the anaerobic digester can process: produce, meats, dairy, oils, bones, fats, liquids, raw food, prepared food, food processing waste, brewery waste and canned and bottled waste. Instead of another pollutant, food waste eventually becomes an alternative energy source, fertilizer and more.

There’s even a pilot project taking place that will use gasses extracted during the biogas purification phase to grow algae, a product that has the potential to revolutionize waste water treatment processes.

Bruce Alder, board chair of Alder Construction, a partner in WRR, sums it up nicely: “We’re being responsible in our own neighborhood. What we’re doing is completing the circle where we end up with a clean product that goes back into the earth and energy production to offset power generation.”

Being responsible in meeting their sustainability goals is what attracted Park City Mountain to this project. Park City Mountain is a part of Vail Resorts, which announced its Commitment to Zero in 2017, an ambitious sustainability goal to achieve a zero net operating footprint by 2030. This commitment includes zero net emissions, zero waste to landfill and zero net operating impact to forests and habitat.

“Park City Mountain’s waste diversion project is a huge step towards our waste goal as we anticipate it will divert 420 tons of waste from the landfill over the next two years,” says Tom Bradley, Environmental Manager for Park City Mountain. “Food waste is a significant percentage of the waste that we are sending to the landfill. The WRR project gives Park City Mountain the opportunity to divert 100% of our food waste.”

After nearly two years of building, WRR started accepting food waste in mid-February, receiving eight tons of food waste on day one. As they continue ramping up the volumes during these early operational days, we’ll check back later in the year to see how it’s all progressing. The anaerobic digester promises to be a game-changer in our community by creating business opportunities that will have a net positive impact on our environment.


Mary McIntyre is the former executive director of the Utah Recycling Alliance, a local nonprofit focused on programs that encourage reuse, recycling and resource conservation. MaryMc@CatalystMagazine.net

For more information check out Wasatchresourcerecovery.com/

This article was originally published on February 28, 2019.