Billions of microbes, and a $100 million waste-to-energy project, quietly dying by Christi Turner

Neat rows of tanks, each with a capacity of 1.7 million gallons, tower above the plains. Three lagoons border the site to the west and north. Pipes of various sizes interconnect the tanks, along with the intake facility, unseen underground pipes, a tapered smaller tank, compressors and other mechanisms, creating a single organism. An unassuming rectangular building, small beside the tanks, houses the control room that oversees the entire site. To the far northern end is one last pipe, which connects to an interstate gas pipeline.

We’re in LaSalle, 60 miles northeast of Boulder in Weld County, the heart of the state’s oil and gas production. But this isn’t another oil and gas site: it’s an anaerobic digester. With its six “bioreactor” tanks, the facility is capable of turning vast amounts of agricultural and food waste into biomethane, a win for both waste diversion and renewable energy. It’s the only facility of its kind in Colorado, and the largest in North America.

And for about nine months, billions of microbes churning inside the bioreactors — specifically methanogens, microorganisms that live at high temperatures and produce methane in oxygen-deprived environments — turned nearly 1,000 tons of waste into energy every day. Lots of energy: at full capacity, the facility could produce 4,700 dekatherms of energy daily, roughly the capacity of a 20-megawatt power plant, which could service around 20,000 homes. The methane, injected into a gas pipeline and sold to Sacramento to support its clean energy goals, was the highest-value product of this digestion process. But it wasn’t the only one. The digester also produced a superior-quality, pathogen-free compost as well as a liquid soil amendment (LSA), both certified by the Organic Materials Review Institute (OMRI) and suitable for organic use.

In the process, it produced almost no waste. Of the nearly 30,000 tons of material that fed the digester each month, much of which would otherwise go to landfill, it was only trashing about 100 tons — about .003 percent of its intake. Everything else was digested into methane, compost or LSA, or sent to be recycled. The digestion facility also accepted packaged food waste — expired milk, cheese, lettuce or otherwise, still wrapped in plastic, or inside a can or cardboard box, or all of the above. It filtered out the packaging using separator machines called a “Doda” and a “Tiger,” as powerful as their names sound. The digester was eating through the equivalent of 243.1 million pounds of food waste and 546 million pounds of dairy manure annually. 

But all of that ended Jan. 28, when Heartland Biogas, who owns the facility, stopped feeding its anaerobic digester. The billions of microorganisms have died. Rows upon rows of finished compost are still curing in the sun. The lagoons are filled to capacity with LSA with no destination. Sacramento has to source its clean energy elsewhere.

Bob Yost, owner of A1 Organics, which operates the intake portion of the Heartland facility, grows animated as he explains this history.

“I’m using my outside voice again,” says Yost, a Weld County native and respected veteran of the national compost industry. “My wife says, ‘Bob, use your inside voice. Take a deep breath, Bob.’”

Read more here.