Characterization of compost biofiltration media

The effect of compost quality on performance of biofiltration media was inv estigated. Three types of compost media were characterized in terms of thei r key properties, including pH, total organic carbon (TOC) and nitrogen, mo isture content, oxygen uptake rates and hetero trophic and fungal plate cou nts. Laboratory-scale biofilter columns were each filled with a different c ompost medium mixed with buffer and a bulking agent. The columns were opera ted with a volatile organic compound (VOC) mixture consisting of ethyl alco hol, butyraldehyde, ethyl acetate, and 1,1-diethoxybutane and subjected to various operating conditions. After 13 months, the columns were sampled and gost-characterization of the media was performed. A mixture of biosolids/horse manure compost, which had a high initial micro bial activity, had the shortest acclimation period. Best overall performanc e, however, was observed with yard waste compost, which was the most stable medium. Media hydrophobicity was a key factor in long-term performance. Si gnificant changes in compost structure, moisture content, pH, volatile soli ds, oxygen uptake rates, and microbial population densities were observed o ver the course of the study. Analyses of organic nitrogen content showed th at significant amounts of nitrogen were not depleted from the media.