Removal of methanol from waste gas using biofiltration.

Biofiltration of methanol vapor from waste gas using compost and wood chips as filter bed material is studied. The biofilter used in this investigation is of 110 cm height and 5 cm in diameter. The inlet methanol vapor concentration is varied from 0.6 to 3.3 ppm with the flow rates ranging from 0.0333 m 3 /s to 0.1000 m 3 /s. The equivalent empty bed residence time (EBRT) range is 9 to 30 s, 12 to 33 s and 15 to 48 s for the bed height of 50 cm, 65 cm and 80 cm respectively. The compost to wood chips ratios of 1:2, 1:1 and 2:1 are employed in this investigation. The effect of inlet air-methanol vapor flow rate, inlet concentration, empty bed residence time, bed height and ratio of compost to wood chips on removal efficiency is studied and found to be significant. The maximum removal efficiency is found to be 93.33 percent and found to strongly depend on the bed height and ratio of compost to wood chips. The percentage removal efficiency is compared with earlier investigation and found to be effective. The biofilter removed as high as 596.06 g m -3 h -1 at the empty residence time of 38 s and the compost to wood chips ratio of 2:1.