Abstract #M214

# M214
The effect of adding zeolites to dairy manure compost on ammonia emissions and nitrogen speciation.
M. E. de Haro Marti1, M. Chahine*2, H. Neibling3, L. Chen2, 1University of Idaho, Gooding, ID, 2University of Idaho, Twin Falls, ID, 3University of Idaho, Kimberly, ID.

Composting of manures and other agricultural wastes is an acceptable and wide spread used waste management technique. As a waste management practice, composting reduces the volume of composted wastes between 35 and 50%, which allows the materials to be significantly more affordable to transport than raw wastes. Most manures, including dairy manure, don’t have the proper carbon to nitrogen ratio (C:N) for composting without the loss of nitrogen as ammonia during the composting process. A zeolite is a crystalline, hydrated aluminosilicate of alkali and alkaline earth cations having an infinite, open 3 dimensional structure. Zeolites are able to further lose or gain water reversibly and to exchange cations with and without crystal structure. The objective of this study was to demonstrate the effects of adding zeolites to the dairy manure compost mix on ammonia emissions and the quality of the final compost product. The study was conducted on a commercial dairy in Southern Idaho. Manure stockpiled during the winter and piled after the corral cleaning was mixed with fresh pushed up manure from daily operations, and with straw from bedding and old straw bales, in similar proportions for each windrow. Windrows were mixed and mechanically turned using a tractor bucket. Three replications of control and treatment were made. The control consisted of the manure and straw mix as described. The treatment consisted of the same mix as the control plus the addition of 8% of zeolites by weight during the initial mix. Windrows were actively composted for 120 d or more with 5 turns per windrow including the initial mix preparation. Data were analyzed using ANOVA. Cumulative ammonia emissions were reduced by 11% in the zeolite treated compost vs. control (2.76 mg NH3-N/m3 versus 3.09 mg NH3-N/m3; P < 0.05) during the first 3 turns which occurred in the first 45 to 55 d of composting. Nitrates concentration in the amended compost (702 mg/kg) was 3 times greater than in the control (223 mg/kg; P = 0.05). The project demonstrated the feasibility of using the addition of zeolites into the composting process as a Best Management Practice to reduce ammonia emissions and to change the nitrogen speciation during the composting process.

Key Words: compost, zeolites, ammonia emission