Nutrient and carbon partitioning and performance for swine manure management technologies

Swine manure management systems (MMSs) are critical for nutrient cycling. Common swine MMS storage types in the United States are deep pits, anaerobic lagoons, and slurry storages. This study presents a synthesis of literature documenting nutrient and carbon (C) partitioning via a material mass balance approach for four manure treatment technologies: acidification (ACID; n = 4 papers), aeration (AER; n = 16), solid-liquid separation (SLS; n = 11), and anaerobic digestion (AD; n = 23) that can be used in-line with one or more of these common storage types. Mass balance data were primarily extracted for nitrogen (N), phosphorus (P), and C (AD only) from lab and pilot-scale studies, with nutrient flows normalized to influent characteristics. The ACID papers suggested significant reductions in gaseous losses with ACID; however, the effluent concentration and available mass/volume and gas data together did not document realistic N partitioning. Among SLS systems, urine-feces segregation and filtration retained the most and least amount of solids in the solid fraction, respectively. AD converts organic matter into biogas; for most mesophilic digesters, 56%-66% of the C remained in the effluent; the mass retained in the sludge is underreported. In AER studies, the partitioning of N into different N gases depended on the amount of AER. As pass-through technologies, AD and SLS are easier to incorporate in lagoon and slurry storage systems. ACID and AER can be physically incorporated in common MMSs; however, treatment could hinder anaerobic lagoon function. Understanding nutrient partitioning will benefit from concurrent monitoring of multiple nutrients in the liquid, solid, and/or gas streams.