When the new Pinnacle Bank Arena opens this fall, it will generate excitement, revenues — and tons of food waste and other garbage.
Dave Dingman, 34, a Lincoln waste energy consultant, believes there's a beneficial use for the tons of food scraps, napkins, drink trays and cups: Instead of landfill disposal or recycling, why not use such biodegradable materials to generate electricity and heat?
He's working on a proposal for a dry fermentation biogas plant that would compost about 20,000 tons of biodegradable waste from the Pinnacle Bank Arena, downtown hotels and restaurants, and the University of Nebraska-Lincoln City Campus.
Here's how it would work: Biodegradable waste would be picked up and hauled to a 50,000-square-foot building and combined with yard waste from the city's compost site. The mixed material would be dumped into five airtight chambers, called digesters, where they would decompose in about a month.
The biodegradable waste undergoes a process called dry fermentation, using anaerobic bacteria. Methane and other gases would be generated by the decomposing material and collected in a large rubberized bladder under the roof of the building. Gas would be siphoned and used as fuel to generate about 1 megawatt of electricity. Heat would be a usable byproduct. The leftover compost would be sold.
European countries have used the dry fermentation process for years, but it's just beginning to take hold in the United States. The University of Wisconsin-Oshkosh has used it since 2011 to produce as much as 5 percent of the campus's electricity and heating needs. And the city of San Jose, Calif., is in the first phase of a similar project. The goal is to process more than 270,000 tons of organic waste annually.
Dingman, owner of Nebraska Organic Waste Energy, envisions starting a pilot project here. He is working with an engineer on a final proposal, which he plans to present to the city of Lincoln and the Lincoln Electric System later this year.
"It's about doing the smart thing. ... It makes sense to me," said Dingman, who earned an environmental studies degree from UNL in 2009 and worked as an energy policy adviser for the Nebraska Energy Office for two years.
He said the dry fermentation process would help save space at the Bluff Road Landfill, reduce fuel and vehicle maintenance costs for waste haulers, generate electricity for LES to use during peak demand periods, reduce greenhouse gases, improve the quality of the city's current compost product and showcase UNL and downtown Lincoln as a "zero waste" community district.
Preliminary cost of the pilot project is $6 million to $10 million, Dingman said. He estimates it would pay for itself in about five years, but the renewable resource benefits could last as long as 30 years.
It is estimated that the arena will produce about 730 tons of waste annually or about 2.4 pounds of waste per visitor, according to UNL's Partners in Pollution Prevention program.
The District Energy Corporation's new building, which will heat and cool the new arena, would be an ideal facility to tie into, Dingman said. Satellite locations could be set up elsewhere in the city.
Odors won't be a significant problem because the airtight chambers holding the organic waste will contain the smell. However, he said, there might be some bad smells emanating from the collection and storage area of the building, he said. Biofilters on top of the roof would help capture odors.
Milo Mumgaard, the mayor's senior policy aide for sustainability, said he has heard of Dingman's proposal and he is personally intrigued by it. Last fall, he toured dry fermentation plants and other renewable projects in Europe.
"It was striking how in Germany they use anaerobic digesters for heat and power everywhere," Mumgaard said. "This isn't rocket science. It's pretty old technology, but it's the kind of thing that has gotten a fresh look-see."
The city already collects methane gas at the landfill, he said, but Dingman's proposal would speed up the process of decomposition of organic waste on a larger scale and produce biogas for municipal use — an idea that has "great merit," he said.
Mumgaard noted that SMG, the management firm for the arena, is under contract to recycle 75 percent of the recyclables, and it is required to "engage" in buying and using materials that are highly recyclable and compostable.
Dealing with the food waste generated at the arena is the next step, he said. The city and LES are exploring using solar, wind and other forms of renewable projects in the West Haymarket as part of the mayor's "Cleaner, Greener Lincoln" initiative, which also includes recycling and waste management.
"All options are on the table for renewable energy projects," Mumgaard said. "The mayor's office is enthusiastic in trying to find and supporting renewable energy as a significant part of the power mix."
LES Chief Operating Officer Doug Bantam said a substantial waste collection and disposal project of this kind would require further investigation.