Monday, April 19, 2010
LL Conference Facility (Hilton Clearwater Beach)
The major barriers to commercial cellulosic biorefineries are conversion technology, and feedstock collection and transportation logistics. Addressing these barriers creates a good opportunity for the scientific community to make significant technological contributions to biobased fuels/chemicals production. Anaerobic digestion (AD) and algal cultivation are existing, natural, biological conversion processes that have been proven effective at converting organic residues into various energy/chemical products including methane biogas, cellulose, starch, and proteins. These processes also help relieve many of the environmental concerns associated with agricultural residues, such as odor, greenhouse gas emissions, and protection of soil and water quality. Considering both the improvement of biorefinery efficiency and the environmental benefits realized from the treatment of agricultural residues, this study developed a novel integrated farm-based biorefinery on a combined feedstock of animal manure and other crop residues to produce ethanol, methane, and other value-added products. The system includes three major components, anaerobic digestion (AD), algal cultivation, and bioethanol production. The AD process will pre-treat the fiber in agricultural residues for bioethanol feedstock preparation. The algal cultivation on AD effluent will further reduce the environmental impacts of odor and excess nutrients associated with anaerobic digestion, and generate a starch and protein rich biomass. Finally, a bioethanol process will utilize the carbohydrates in AD treated fiber and algal biomass to produce ethanol. The results have demonstrated the increase of cellulose content during the anaerobic digestion process, significant enhancement of the subsequent conversion of the cellulose in this AD pretreated fiber to sugars, and improved algal growth on liquid AD effluent. These results suggest that integration of anaerobic digestion, algal cultivation, and ethanol production might be one of sustainable approaches towards renewable energy solution.