Treatment of air polluted with methanol vapours in biofilters with and without percolation

Air polluted with methanol vapours was treated in a biofilter and a biotrickling filter, both packed with inert materials. The effects of the nitrogen concentration present in the nutrient solution, the empty bed residence time, and the methanol inlet load, on the biofilter and biotrickling filter performance were all examined and compared. The elimination capacity, the biomass and the carbon dioxide production rates all increased with the increase of the parameters tested. The maximum elimination capacity for the biotrickling filter was 240  g·m−3·h−1with corresponding removal efficiency of 75% and carbon dioxide production rate of 10  g·m−3·h−1, whereas the maximum elimination capacity for the biofilter was 80  g·m−3·h−1with corresponding removal efficiency of 35% and carbon dioxide production rate of 70  g·m−3·h−1. The biomass production rate was similar for both the biofilter and the biotrickling filter. The carbon dioxide production rate was higher by a factor of 2 to 9 for the biofilter compared to the biotrickling filter.