The city of Akron, Ohio, is perhaps most famous for tire manufacturing. As the headquarters city of Goodyear and other tire companies over the last century, it has earned the nickname Rubber City. But in recent years, the dually nicknamed, City of Invention, has been making a name for itself in yet another way. Its use of technologies which are producing energy from human biowaste solids has Akron emerging as a national leader in energy from waste technology development.
The city of Akron has had a public-private partnership since 1989 with then-named KB Compost to manage waste solids through the city’s composting facility. In 2007, the city contracted with what is now KB BioEnergy to construct and manage an anaerobic digestion (AD) system (Phase I) to process one-third of the city’s biowaste solids.
After five years of successful processing of the waste to produce power for the wastewater treatment plant, the city renewed its contract with KB BioEnergy to develop a larger AD facility that could accommodate 100 percent of the city’s biosolid stream. KB BioEnergy invested $32 million for the upgrade and expansion.
The newly named Akron Renewable Energy Facility uses technology from German-based Viessmann Group companies Schmack Biogas GmbH and BIOFerm Energy Systems. Applied Technologies, Brookfield, Wis., was responsible for the design and construction review of the project. PNC Bank, Pittsburgh, provided the majority of the financing.
Open for business
Members of the public and city officials from Akron, Ohio, came together Oct. 30, 2013, to dedicate the new Akron Renewable Energy Facility. The facility converts biosolids into electricity and heat and uses what remains after the process to produce pelletized organics.
BIOFerm describes the AD process as the heating of biosolids while bacteria break down the organic matter into methane and carbon dioxide, which is called biogas. The new AD facility or Phase II, is a two-tank digester system and is three times larger than the initial pilot anaerobic digester built in 2007.
According to KB BioEnergy, while traditional AD technologies can process material ranging from 3 to 5 percent solids, the system in Akron can handle up to 30 percent solids content, which could open doors for other waste streams to be processed in the digesters. The facility is designed to process 15,000 dry tons of biosolids annually, producing 600 cubic feet per minute (cfm) of biogas. The resulting biogas is used for heating and electricity. The facility is expected to generate 12,192 megawatt hours of electricity in 2014 or the equivalent of what it takes to power 1,600 homes.
During the ribbon-cutting ceremony, Annette Berger, vice president of operations for KB BioEnergy, said, “Today is the culmination of an enormous collective effort which began in 2005 when the concept of anaerobic digestion was considered.”
At that time, she said composting had been serving the city well for more than 25 years. The only drawback in that technology was the odor, she said. “So we searched and built a pilot project in 2007, that would manage one-third of the solids that we typically would have composted.”
Side benefit
Akron Mayor Donald Plusquellic went into further detail about the city’s decision to move away from composting its biosolids and toward AD. “We took waste material and turned it into something that was useful in many gardens and flowerbeds across the country as well as Keep Akron Beautiful,” he said. “It helped beautify the city, and that was a good thing, but as we looked at technology and looked down the road, the important part was to keep ahead of the technology.”
Plusquellic said he attended a trade fair in Hanover, Germany, 10 years ago, to recruit businesses to Akron. A spin-off benefit from that visit indirectly benefitting the citizens of Akron was his trip to Zurich, Germany, to learn about AD technology, “It worked there,” he explained. “There was no reason it couldn’t work in the United States, even though no one was using it. That side benefit,” he added, “we see here today.”
Brian Gresser, manager of Akron’s Water Reclamation Facility, which provides the sewage sludge to the digester, says that wastewater utilities can reduce costs and increase sustainability because the energy generated from the biosolids is greater than the energy needed to treat them. In 2012, the Water Reclamation Facility also began using energy captured from an adjacent landfill to help offset its electricity needs. With the addition of the larger AD facility, Gresser said, “We will be able to supply all of our electricity needs through on-site generation from renewable sources.” He added, “This is a notable achievement coming from a facility that historically is one of the largest users of electricity in the region.”
Thomas Kurtz, president of KB BioEnergy, said, “The table is set now to run a facility that will manage solids in the city of Akron for multiple generations.”
The author is managing editor of Renewable Energy from Waste and can be contacted at ksmith@gie.net.
A video from the October 2013 dedication of the Akron Renewable Energy Facility is available at www.REWmag.com/kb-bioenergy-akron-video.aspx.