Treatment of Toluene-Contaminated Air Using a Rotary-Type Biofilter and Highly Porous Packing Material

Volatile organic compounds (VOCs) are potentially malodorous, toxic and carcinogenic. Toluene is an important VOC used in diverse industries. This study was conducted to examine the operating parameters of a newly developed rotary-type biofilter having polyvinyl formal (pvf) as the packing material. Air contaminated with toluene was fed into the biofilter in an up-flow mode. Air samples obtained were analyzed with a gas chromatograph (GC) equipped with a flame ionization detector (FID). Nutrient solution was supplied daily to the filter bed to provide nitrogen. Nutrient samples were analyzed using indophenol blue method. Pressure drop, room temperature, and CO₂ concentrations were monitored daily. The results obtained showed that the biofilter was very efficient in treating the toluene-contaminated air. As the inlet load increased, elimination capacity increased while removal efficiency decreased. The maximum inlet load, elimination capacity, and removal efficiency obtained were 162.3 gm^-3h^-1, 120.7 gm^-3h^-1, and 99.98%, respectively. Concentration of ammonium nitrogen in the nutrient solution decreased over time because microorganisms utilized the nitrogen for metabolic processes.