Effects of operating temperature and supplemental nutrients in a pilot-scale agricultural biofilter

摘要

In this study, the objective was to determine if different operating temperatures and/or the addition of supplemental inorganic nutrients affected the odour removal capacity of two pilot-scale, closed-bed biofilters. The biofilters were filled with amixture of three parts crumbled polystyrene particles and one part peat moss (by volume). Air from a swine manure treatment plant was passed in parallel, upward through the filters. Three, four-week trials were performed at each of three different operating temperatures (15.0,22.5, and 30.0 deg C). Supplemental nutrients (KH_2PO_4, NH_4C1, MgCl_2, and CaCl_2) were added to one of the two biofilters during each trial. The inlet and outlet air streams were sampled and the odour concentration of the samples was determined using an eight-panelist, triangular, forced-choice olfàctometer. The results of the study were extremely variable, partly because of unstable and non-uniform moisture conditions in the filter bed. The mean reduction in odour concentration for all trials was 41 %. Differences in treatment temperature had no apparent influence on odour removal (p = 0.05). The addition of nutrients did result in an apparent increase in odour removal (from 38 to 45%), but this change was not statisticallysignificant (p = 0.05).