Control of composting odor using biofiltration

摘要

fWhile composting transforms manure wastes into useful fertilizer, it also produces odors during the decomposition process. Biofiltration is a desirable method to control composting odor. This study was conducted to investigate the efficiency of using compost as a biofilter. A mixture of cattle manure and fresh compost was composted in a bin equipped with a suction-type blower. The exhaust gas was filtered through the biofilter of fresh compost. The composting temperature affected the ammonia emission. When the composting temperature was relatively high, the highest ammonia emission appeared in two experiments. The biofiltering properties were investigated according to flow rates and filter depths for two different types of fresh composts (experiment I and II). At the flow rate of 30 L / min, ammonia removal rate was 80.5% for biofilter A(detention time 56.5 s) and 99.9% for biofilter B (detention time 113 s). At the flow rate of 50 L / min, the ammonia removal rate was 82.5% for biofilter A (detention time 33.9 s) and 97.4% for biofilter B (detention time 67.8). The fresh compost could be used as a biofilter medium for odor control during composting process. The moisture content(MC) of the biofilter material increased by absorbing moisture from the exhaust gas, while the pH was decreased due to the degradation of nitrogenous compounds. As the moisture in the exhaust gas increased the MC of the biofilter, there was no need to spray water to the biofilter medium to control moisture content. While the total nitrogen(T-N) of the biofilter increased by absorbing ammonia, the total carbon (T-C) remained unchanged resulting in decrease of the C/N ratio.