Absorption of Ammonia Gas from a Composting Plant using Carbonated Water

Odors from composting plants are a serious public nuisance. Ammonia gas (NH3) is the main molecule responsible for bad odors that arise from composting of organic wastes such as animal manure. Carbon dioxide (CO2) is known to increase the solubility of NH3 in water. Taking that effect of CO2 into account, numerical calculation of the absorption of NH3 into water was carried out under the assumption of quasiequilibrium conditions. Based on that theoretical consideration, the authors propose a new deodorizing process that consists of a carbonator and a reactor. The carbonated water produced by pressurized CO2 gas is transported to the reactor, where NH3 gas dissolves efficiently in the water. Carbonated water with NH3 is useful as a liquid fertilizer.It is expected that the consumption of water in the new process is significantly lessened compared to that consumed in traditional processing. According to theoretical considerations, 100ppm NH3 in 1m3 air can be reduced to 10ppm after deodorization using 0.1kg carbonated water at CO2 concentration of 2×10-3kg L-1.