Small-scale Anaerobic Digestion in the United States: Design Options and Financial Viability

Anaerobic digesters were first widely constructed in the United States during the 1970’s energy crisis. Within the anaerobic environment inside a digester, methanogenic microorganisms, utilize organic matter, carbon dioxide, and hydrogen to produce methane, resulting in the creation of renewable energy with decreases in greenhouse gas emissions, organic pollutants, pathogens, and odor (Martin, 2004). Unfortunately, poor economic viability and technical flaws led to a 60% failure rate of these systems (Bishop and Shumway, 2009). Through improved designs, the world is currently seeing a revitalization of anaerobic digestion technology with over 30 million manure-based digesters operating globally (Chen et al., 2010; Rao et al., 2010).