|Rice, J. - NCSU, RALEIGH, NC|
|Humenik, Frank - NCSU, RALEIGH, NC|
Submitted to: New Zealand Journal of Agricultural Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 30, 2004
Publication Date: December 1, 2004
Citation: Szogi, A.A., Vanotti, M.B., Rice, J.M., Humenik, F.J., Hunt, P.G. 2004. Nitrification options for pig wastewater treatment. New Zealand Journal of Agricultural Research. 47:439-448. Interpretive Summary: Nitrification is a necessary and often limiting process in animal waste treatment for biological removal of nitrogen. Three technologies were evaluated for enhancing nitrification of nitrogen-rich swine lagoon wastewater: overland flow, trickling filter, and nitrifying pellet technology. Overland flow is a low-intensity system that can remove large amounts of N per unit area through nitrification and partial denitrification. Performance data showed N removal rates of 22 to 42 kg N/ha/day. Trickling filter is a medium-intensity system that is popular among small waste generators. Nitrification efficiency was 57 percent at total N loading rates of 249 g/cu.m/day. Nitrifying pellets technology is a high-intensity system using fluidized bioreactors designed for fast and efficient removal of ammonia. Nitrification efficiencies of 91 percent were obtained at total N loading rates of 438 g/cu.m/day, and 42 percent at 1349 g N/cu.m/day. Two conclusions are suggested from this research: (1) that substantial nitrification of lagoon swine wastewater can be attained particularly using aerobic treatments with enriched nitrifying populations; and (2) that large mass removal of N from swine wastewater may be possible by sequencing nitrification and denitrification unit processes.
Technical Abstract: Nitrification is a necessary and often limiting process in animal waste treatment for removal of nitrogen as N2 through biological nitrification/denitrification systems. We evaluated three technologies for enhancing nitrification of swine lagoon wastewater prior to denitrification: overland flow, trickling filter, and a bioreactor using nitrifying pellets. The overland flow system consisted of a 4- by 20-m plot with 2 percent slope receiving a total N loading rate of 64 to 99 kg N/ha/d. Total N removal efficiency ranged from 35 to 42 percent, and 7 percent of the total N application was recovered in the effluent as nitrate. The trickling filter consisted of a 1-cu.m tank filled with marl gravel media which supported a nitrifying biofilm. Lagoon wastewater was applied as a fine spray on the surface at hydraulic loading rates of 684 L/cu.m/ d and total N loading rates of 249 g/cu.m/ d. The media filter treatment transformed up to 57 percent of the inflow total N into nitrate when wastewater was supplemented with dolomitic lime. The nitrifying pellets technology used acclimated nitrifying cells immobilized in 3- to 5-mm polymer pellets. Swine wastewater was treated in an aerated fluidized reactor unit with a 15 percent (w/v) pellet concentration. Nitrification efficiencies of more than 90% were obtained in continuous flow treatment using total N loading rates of 438 g N/cu.m/ d and hydraulic residence time of 12 h. Two conclusions are suggested from this research: (1) that substantial nitrification of lagoon swine wastewater can be attained particularly using aerobic treatments with enriched nitrifying populations; and (2) that large mass removal of N from swine wastewater may be possible by sequencing nitrification and denitrification unit processes.