The Characteristics of Organic Degradation and Ammonia Volatilization in the Liquid Composting of Pig Slurry

Abstract

This study was carried out for 30 days in aeration type and agitation type reactor to characterize organic matter decomposition and ammonia volatilization during the liquid composting of pig slurry, and organic matter and nitrogen removal rate through mass balance analysis was analyzed. In the aeration type reactor, the pH increased from 7.0 to 9.13, and TS 34.5%, VS 33.4%, BOD5 71.2%, CODCr 62.3% and TOC 83.2% were removed. In addition, 44.6% of TN and 65.0% of NH4+-N were removed. In the agitation type reactor, the pH increased from 7.0 to 8.10, and the removal rates of TS 0.9%, VS 0.5%, CODCr 27.5%, BOD5 28.9% and TOC 41.3% were obtained. And TN and NH4+-N showed removal rate of 25.3% and 29.2%, respectively. The first order kinetics constant related to BOD5 degradation was -0.039 day-1 for aerobic liquid composting and -0.013 day-1 for agitated reactor. Nitrogen loss in aerobic liquid composting was about 2.3 times higher than that of agitated reactor, whereas FAN/TAN in aerobic liquid composting was about 7.9 times higher than that of agitation type reactor. Therefore, despite the low FAN/TAN in the agitation type reactor, the nitrogen loss rate was relatively high. First-order kinetic for BOD5 degradation during the liquid composting.