Anaerobic digestion is a notable waste management technology that produces renewable energy while improving livestock manure management. The process reduces the release of greenhouse gas emissions (GHGs), volatile organic compounds, pathogens, and odors. Since their inception, some dairy digesters have used “add-on” technologies to improve project economics and address other environmental and management concerns. These add-on technologies convert traditional dairy digesters into dairy manure bio-refineries that integrate the core anaerobic digester with additional downstream equipment to generate value-added products including fuels, power, and chemicals. This publication provides an overview of the bio-refinery concept as applied to a dairy digester, and describes the technologies currently receiving the most interest for use with on-farm dairy digesters. This publication serves as an introduction and overview for the Anaerobic Digestion Systems Series, which provides research-based information to improve decision-making for incorporating, augmenting, and maintaining anaerobic digestion systems for manure and food by-products
