Review of Emerging Nutrient Recovery Technologies for Farm-Based Anaerobic Digesters and Other Renewable Energy Systems

This report reviews emerging technologies for recovering nutrients and other valuable products from dairy manure streams associated with anaerobic digestion systems. The authors examine approaches designed to capture and concentrate nitrogen, phosphorus, salts, and other constituents from digested manure, allowing these materials to be reused as fertilizers, soil amendments, or other agricultural inputs. The report frames these technologies within a broader dairy biorefinery concept in which anaerobic digestion is combined with additional treatment and recovery processes to produce renewable energy and marketable co-products.

Several categories of technologies are discussed, including phosphorus recovery systems such as struvite crystallization, nitrogen recovery approaches such as ammonia stripping, integrated nutrient recovery systems, and technologies that remove salts or recover clean water from manure streams. The report evaluates technical performance, integration with farm-based digesters, and economic considerations that influence adoption by dairy operations. This report was prepared for the Innovation Center for U.S. Dairy.