Concentrated animal feeding operations (CAFOs) continue to experience every increasing pressure regarding nutrient overloads and air and water environmental concerns on their farms. Additionally the producers are subject to every growing and skyrocketing fuel and fertilizer costs. This USDA SBIR Phase I project aims to demonstrate an innovative technology that recovers ammonia nitrogen from CAFO anaerobic digester (AD) manure effluent and turn an environmental liability into a product that can be exported off the farms. The anticipated result of the project is the development of a technology that can be integrated into the existing AD processes to expand AD's capability in nutrient recovery. The additional capital costs and operating costs incurred by inclusion of the technology will be in part remediated by providing both a nutrient-decreased effluent and saleable bio-fertilizer products. OBJECTIVES: This pilot project will test the feasibility of treating animal waste anaerobic digester effluent for removal and recovery of ammonia in the form of saleable ammonia sulfate bio-fertilizer, using the unique characteristics of the AD effluent to more optimally and efficiently treat the ammonia while also concurrently scrubbing the AD biogas of acidic compounds and increasing its methane content and value. The objectives of the project are to (1) fabricate and install a 2 gpm pilot system within the framework of a commercial dairy operating associated AD and solids recovery units; (2) operate, evaluate and refine specific unit operations of the system; and (3) use collected data and unit operation capabilities in developing a techno-economic evaluation of the entire system for eventual business plan development and future scale-up. Specific unit operations that will be tested include the: pH adjustment/solids settling chamber; closed-loop ammonia stripping column; ammonia sulfate recovery column; and pH readjustment and biogas scrubbing sparger system. APPROACH: The project methods include pilot-testing of unit operations within the entire integrated framework as well as techno-economic assessment of the unit operations and entire system through analysis of mass/energy balances and input/output costs/values. Engineering scale-up methods will be utilized in conjunction with unit operation refinements and economic evaluation to produce a viable, scaled commercial system for eventual commercialization
