2006 Volume 37 Issue 2 Pages 110-121
For the purpose of improving biological VOC (Volatile Organic Compounds) treatment from the viewpoint of performance and stability, a new design “Switch-Feed Multi-Column Biofiltration” was proposed, and experiments were carried out using gaseous toluene as the target pollutant. In this study, operating conditions in the newly proposed design were simulated experimentally by connecting three packed columns of PVF (Poly-Vinyl Formal) medium in series, by switching the gas flow line periodically, and by washing packed columns at the timing of flow line switching. Results showed that the increase of nitrogen, which was included in the nutrient solution used for washing, brought higher toluene removal efficiency, and that about 60% of water content was the optimal condition for the packing material. Excess biomass in the packed layer did not be eliminated only by the physical washing process provided as liquid flow, and it was suggested that chemical treatment was effective to control biomass. The newly developed PVF medium, which has 2.0mm of average pore diameter and 96% of porosity, provided the first-order kinetics of toluene removal under the range up to 200ppmv of inlet toluene concentration. Moreover, the new PVF medium maintained nearly maximum toluene removal under 40-80% of water content. Approximately 0.05sec-1 of the first-order kinetics coefficient (sorption rate coefficient) was obtained as average toluene removal, and removal capacity against 200 ppmv of toluene concentration was within the range from 140 to 200gm-3h-1.
