Treatment of styrene and toluene vapors in lab-scale biofilters : elimination capacity and growth yields determination

Biofiltration of styrene or toluene vapors was performed respectively in a biotrickling filter (BTF) with 52 L of polypropylene rings and a biofilter (BF) filled with 25 L of organic compost to study the reactors' elimination capacity (EC) and the microbial respiration activity. The biofiltration of styrene vapors confirmed the role of nutrient addition for maintaining highest elimination capacity level (EC = 0.368 mol m-3 .h -1 +/- 0.051, n = 9). Without a nitrogen source, however, the EC level was 0.255 mol m-3 .h-1 +/- 0.039 (n = 6). The biofiltration of toluene vapors showed a maximum elimination capacity of 2.01 mol.m-3.h-1 and the ability of the biofilter to respond at inlet load changes (0 mol.m-3.h-1 to 4.08 mol.m -3.h-1) applied over a short period (4 days). In both experiments, the dioxygen uptake rate (O2UR) and the carbon dioxide production rate (CPR), followed using an on-line respirometer, showed to be function of the pollutant organic load and, in the biofiltration of styrene vapors, depended on the presence of a N-source. Growth yields parameters calculated from O2UR and CPR data were similar to the predicted yields from the stoichiometric equation of the bioxidation of styrene or toluene