Check out a photo slideshow of this project here.

The most recent of these biogas plants, the $16 million JC-Biomethane LLC project, had been in the company’s sights for more than five years. The new plant in Junction City, Oregon, which opened in mid-2013 is anaerobically digesting organic material to generate methane-rich biogas, which then fuels a generator for the production of electricity. This project carried particular importance for its founders, since they happen to live in the area. But beyond the personal connection to the region, there were other local factors that made the site an excellent location to demonstrate the potential for similar facilities across the country.

A translucent polyethylene fabric roof allows ample natural light into the building, reducing the need for artificial lighting on the operations floor. Credit: Legacy Building Solutions.

“The community here is very focused on sustainability, landfill diversion, renewable energy,” said Dean Foor, project engineer for EC Oregon and chief executive officer of JC-Biomethane. “Between federal grants, state tax credits and a $2 million contribution from the Energy Trust of Oregon, we had a good groundwork here for developing this type of project.”

While still in the development phase, the project did encounter one early wrinkle that dictated a modification to the original facility plans. The expiration of a tax incentive tied to pre-consumer food waste forced the plant to turn to post-consumer food waste as its feedstock source. This twist of fate ultimately gave JC-Biomethane the distinction of being the largest U.S. biogas plant focused exclusively on post-consumer food waste.

“The field of waste management as a whole seemed reluctant to embrace the technology of processing food waste into biogas,” said Foor. “The technology needed a push to make it happen and show its potential.”

The biggest adjustment from the change in feedstock was to the design of the receiving building. Instead of handling clean organics, JC-Biomethane would need a separator to remove contaminants from the food waste. The company also wanted to account for odor control and greater storage capacity requirements. In short, the receiving building on site would need to be much larger.

At the recommendation of Evergreen Engineering, JC-Biomethane turned to Legacy Building Solutions to provide a tension fabric building to receive waste for the plant. In contrast to traditional tension fabric structures, Legacy buildings feature a rigid frame design that utilizes structural steel I-beams, which allows the manufacturer to customize to the exact length, width and height needed.

“Essentially we modeled up the dimensions we would need to accommodate trucks making deliveries and loaders operating inside of the building,” said Foor. “We also needed space to house different equipment arrangements and hold the amount of inbound material we anticipated. The height needed for truck tipping was another consideration.”

The end result supplied was a 120 x 160 foot structure with a polyethylene roof that peaks at a height of 47 feet. The building is outfitted with Rytec high-speed fabric doors for truck entry, and also includes a two-story office complex within the envelope of the larger structure.

“We have about 3,600 square feet of office space inside the building,” said Foor. “We did some retrofitting in that area of the structure late in the process as well. Our architect worked with Legacy on a modification to provide an exposure from our offices to the western view. The whole engineering phase with Legacy was excellent. They were very responsive to our ideas and turned things around very quickly. Even the installation was fast – the whole building was erected in about seven days.”

Odor Control Technology: A First for North America

Legacy’s structural steel frame design allowed JC-Biomethane to mount equipment from the I-beams as well. The receiving building includes a special odor control system, a feature that isn’t legally required by federal or state regulations, but that Foor and others determined would be advantageous both for plant workers and neighboring businesses and residents.

The odor control system is comprised of two large hoods established over receiving areas where the food waste resides for extended periods of time. A vacuum over the area pulls in the atmospheric gases emitting from the waste and moves the contaminated air through ducting to an ozone system just outside the building. A series of 132 UV lamps create ozone, which reacts with any volatile odors and neutralizes them.

“We’re basically pooling multiple exchanges of air per hour through our building and using an ozone reaction to control odor,” said Foor. “It’s a unique application. This technology is used at biogas plants in Europe, but we don’t know of any other biogas plant in North America that has used ozone for odor treatment. We think that’s a first.”

Other Unintended Benefits

Though the fabric building was chosen primarily for its customizability and overall efficiency for the application at hand, JC-Biomethane immediately started noticing additional environmental and cost benefits from the structure.

“The fabric roof allows a lot of natural light into the building, which is a big advantage on the operations floor, since it reduces our need for artificial lighting inside,” said Foor. “It provides significant sheltering from rain, wind and cold. Even though we didn’t have it insulated, it’s still noticeably more comfortable inside during the winter. We thought it might be hot to work in during the summer, but the structure actually provides more of a shading and cooling effect.”