- Project will research production of biogas from yard waste, corn residue and bioenergy crops for conversion to electricity and transportation fuels.
Awarded through the(BRDI), the three-year grant will also allow researchers to develop technology for converting biogas to liquid hydrocarbon fuels, with the aim of further diversifying the country's currently available suite of renewable transportation fuels.
University partners in the grant include Mississippi State University and the University of Georgia. The project's main industry partner is, a Cleveland-based company that operates several anaerobic digesters (systems that produce biogas from organic waste) in Ohio and Massachusetts, including one on OARDC's Wooster campus. Other industry partners include AgSTAR, Aloterra Energy, American Electric Power, CNH and Marathon. OARDC is the research arm of the College of Food, Agricultural, and Environmental Sciences.
The project's main goal is to enhance the integrated anaerobic digestion system (iADs), a patent-pending technology developed by OARDC and operated by quasar. The system combines quasar's commercial liquid biodigester with a novel solid-state or "dry" biodigester. This combination allows the overall system to process types and amounts of dry biomass -- such as yard waste, crop residue and lignocellulosic food waste -- that the liquid biodigester can't handle alone.
"The iADs can treat and recover energy from organic materials with up to 85 percent solids content," said Yebo Li, the OARDC biosystems engineer who invented the integrated system and the grant's principal investigator. "By comparison, liquid biodigesters currently used in the United States can only process up to 14 percent solids content."
In the anaerobic digestion world, this difference is very important. Biogas is produced from the solid nutrients present in the biodigestion process, so the more solids that go in, the more biogas that comes out. Another advantage of this system is that it significantly increases the amount of biomass that can be fed to biodigesters and transformed into energy, allowing this budding green industry to expand and create new jobs.
The first iADs was built in 2012 next to quasar's biodigester in Zanesville, Ohio, and can process 8,000 tons of waste annually. Construction of this system was supported by a $2 million grant from the state of Ohio's Third Frontier Advanced Energy Program.
"The BRDI funding leverages our 2010 Third Frontier award, expanding the public-private partnership between The Ohio State University and quasar,” said quasar president Mel Kurtz. "Work related to this grant will be performed at our energy campus in Zanesville -- quasar's largest facility and proving ground for iADs development."
The new grant will allow Li and collaborators to research production of biogas from three feedstocks: yard waste, corn stover and giant miscanthus (Miscanthus x giganteus). Giant miscanthus is a perennial warm-season grass from Asia that is garnering attention across the Midwest as a potential bioenergy crop. Researchers at OSU South Centers at Piketon have been testing the crop's adaptability to Ohio since 2010.
Project collaborators Rattan Lal, an Ohio State soil science expert, and Denny Hall, assistant director of the university's Ohio BioProducts Innovation Center, will evaluate the nutrient-rich "digestate" left over from the anaerobic digestion process as a fertilizer to grow giant miscanthus on strip-mined land not suitable for traditional crops.
Additionally, Scott Shearer, chair of Ohio State's Department of Food, Agricultural and Biological Engineering, will study biogas feedstock logistics, including the use of a methane-fueled truck to both transport the digestate to the field and bring the miscanthus biomass back to the biodigester.
The idea, Li said, is to "close an ecological loop," reducing transportation costs while improving soil fertility and crop yield. To that extent, Bhavik Bakshi, a researcher in Ohio State's Department of Chemical and Biomolecular Engineering, will conduct a life-cycle analysis to determine the economic and environmental impact of the dry biodigester technology.
While biogas can be burned to produce electricity or compressed to use as vehicle fuel, the project will also seek to expand its use in transportation by developing a technology to convert biogas to liquid hydrocarbon fuels -- so that it can be used just like gasoline. Scientists will use techniques such as catalytic reforming and Fischer-Tropsch synthesis to achieve that goal.
Another aim of the project is to develop a technology for pretreatment of lignocellulosic biomass. Pretreatment, Li said, can enhance the "digestibility" of this biomass in the dry biodigester, leading to higher biogas production. Another project collaborator, Zhongtang Yu of Ohio State's Department of Animal Sciences, will study the microbial community present during the anaerobic digestion of pretreated feedstocks.