Generation 3 Treatment Technology for Diluted Swine Wastewater using High-Rate Solid-Liquid Separation and Nutrient Removal Processes

Abstract

<abstract> <bold>Abstract.</bold> The primary objective for this project was to construct and evaluate a third generation, innovative swine manure treatment system. The system was designed to: separate solids and liquids with the aid of settling and polymer flocculants; biologically remove ammonia nitrogen with bacteria adapted to high-strength wastewater; remove phosphorus via alkali precipitation; and reduce emissions of odorant compounds, ammonia, pathogens, and heavy metals to environmental media. Technical environmental performance standards were those identified by the State of North Carolina in 15A NCAC 02T, 2010, Swine Waste Management System Performance Standards and included: discharge of animal waste to surface waters and groundwater; emission of ammonia; emission of odor; release of disease-transmitting vectors and airborne pathogens; and nutrient and heavy metal contamination of soil and groundwater. The third generation was designed to further reduce cost of manure treatment through pre-concentration of diluted manure using a decanting tank before polymer flocculation. The treatment system was demonstrated full-scale on a farrow-to-finish farm that produced 30,450 swine per year. The treatment system was contained in tanks. The results showed that the innovative swine manure treatment system was capable of operating under steady state conditions treating flushed swine manure at a rate of approximately 75,000 gallons of manure per day. The treatment system was documented to remove, on a mass basis, approximately 99% of total suspended solids, 98% of COD, 99% of TKN, 100% ammonia, 100% odor compounds, 92% phosphorus, 95% copper, and 97% zinc from the flushed manure. Fecal coliform reductions were measured to be 99.98% (when the alkali precipitation component of the system was at a pH of 10.1). The third generation technology meets the criteria identified in the referenced NC Performance Standards. The treatment process also provides a mechanism and market for the solids that are separated. Collectively this treatment process, when operated and managed under the conditions during which we conducted this study, significantly reduces the potential for emissions of odor and ammonia, and the transfer of nutrients and pathogenic bacteria to surface and groundwater in the drainage basin where the animals are grown on animal feeding operations.