Study on the effect of surface organic acid treatment on inhibiting nitrogen loss in trough composting

To reduce the ammonia loss during the trough composting process and the problem of low initial pH of the compost due to one-time addition of organic acids. In this study, we investigated the feasibility of buffering the pH of the compost and controlling the ammonia emission through the addition of dilute acetic acid sprayed on the surface of the compost pile after several pile-turnings in the trough composting process. The results showed that the spraying of acetic acid did not have a significant difference in the effect on the initial pH and maintained a slightly alkaline environment throughout the composting process, which led to an increase in the degradation rate of 58.38% at the end of the composting process. Compared with natural composting, the pile-turning of trough compost increased the ammonia volatilisation by 125.53% and nitrogen loss by 10.75% during the composting process, but the spraying of 0.005 mol/L dilute acetic acid solution and water on the surface layer of the heap could reduce the ammonia emission of the heap, which was reduced by 36.31% and 17.81%, and the rate of nitrogen loss was reduced by 12.63% and 3.59%, respectively. This study suggests that acetic acid is a suitable additive for composting. Spraying acetic acid after compost turning not only stabilises compost pH, but also reduces ammonia volatilisation loss. It provides a reference for the efficient ammonia reduction technology of compost.