Submitted to: Electronic Publication
Publication Type: Research technical update
Publication Acceptance Date: 3/6/2013
Publication Date: 9/16/2013
Citation: Vanotti, M.B., Hunt, P.G., Rice, M., Kunz, A., Loughrin, J.H. 2013. Evaluation of generation 3 treatment technology for swine waste - A North Carolina's clean water management trust fund project - Technical environmental performance report. Electronic Publication [on line]. Available: http://www.cals.ncsu.edu/waste_mgt/smithfield_projects/CWMTF-Report.pdf. 1-50. Interpretive Summary:
Technical Abstract: This project evaluated and demonstrated the viability of a third generation manure treatment technology. The technology was developed as an alternative to the lagoon/spray field system typically used to treat the wastewater generated by swine farms in North Carolina. It separates solids and liquids with the aid of settling and polymer flocculants; it biologically removes the ammonia nitrogen with bacteria adapted to high-strength wastewater; it removes phosphorus via alkali precipitation; and it substantially eliminates release into the environment of odors, pathogens, ammonia and heavy metals. The third generation was designed to further reduce cost of manure treatment by economies of scale from installation in larger farms, and through pre-concentration of diluted manure before polymer application. The technology was installed and tested full-scale on a 2,522,386 pounds steady state live weight (SSLW) Farrow-to-Finish farm that produced approximately 30,450 hogs per year in Wayne County, North Carolina. The system treated the waste stream from two operations: a 1,200-sow Farrow-to-Feeder operation that used flushing system and generated 27,140 gallons (gal) of manure per day, and a 12,960 Feeder-to-Finish operation that used pit recharge system and generated 48,388 gal of manure per day. The treatment system was contained in tanks and replaced two anaerobic lagoons. Objectives were the evaluation of technical and operational feasibility and environmental performance standards related to the elimination of discharge of animal waste into waters and the reduction of ammonia, phosphorus, odors, pathogens and heavy metals in the treated effluent. Additional objectives were to assess benefits of decanting tank that pre-concentrated the flushed manure from the sow farm. The system was evaluated for 12 weeks under steady-state conditions. Major goals in the demonstration and performance verification of the third generation alternative treatment system for swine manure were achieved. These include highly efficient treatment performance with high hydraulic loads typical of flushing systems and high strength wastewater typical of the pit-recharge systems. Implementation of the decanting tank in the flushing waste stream reduced the total manure volume processed by the solid separator press by 25,860 gal/day and increased polymer use efficiency 5.4 times. The treatment system removed 97.3% of the total suspended solids, 93.7% of the COD, 97.7% of the TKN, 99.0% of ammonia, 88.5% of total phosphorus, 95.4% of copper, and 97.0% of zinc. The treatment system removed 100% of odor compounds in the liquid including skatole and volatile fatty acids. The system can meet 15A NCAC 02T standard for pathogens when the process pH in phosphorus module is adjusted to 10, and can meet the stricter Senate Bill-1465 pathogens standard (4 log reduction) when operated at 10.5. The major goals in the demonstration and verification of a third-generation wastewater treatment system for swine manure were achieved. These goals included replacement of anaerobic lagoon treatment, adaptation of the system to receive higher volume of liquid waste typical of flushing systems, and efficient environmental performance when installed in larger swine farms.