Industrial application of bio-filteration systems for treatment of waste gas streams

Bioprocesses for waste gas treatment have been developed as more economical alternatives to conventional, physico-chemical technologies. Major bioprocesses used nowadays for the treatment of polluted air could be categorized as biofilters, biotrickling filters, and bioscrubbers. Conventional biofilter based on an organic packed bed, has been used for several decades for the removal of odors, mainly at wastewater treatment plants and composting facilities. Due to some drawbacks, research on biotrickling filters (BTFs) using artificial packings and circulating nutrient solution, started in the 1980s, mainly in Central-Western European countries. Nowadays, BTFs have become quite popular for removal of VOC and sulfur-containing pollutants from industrial waste gases.In a recent project in Iran, a bio-filtration process was exploited to treat soil vapors extracted from an industrial contaminated underground-water. Reactor working volume was 5000 liter packed with Polypropylene Pall-ring (2 inch) Packing with a nutrient tank capacity of 500 liter. The maximum inlet air flow rate was 150 m3 /h with 1000 ppm ethylbenzene as the main pollutant, and following the biofilm formation removal efficiency of around 90 % was achieved. The results showed good and robust performance of the biotrickling filters and promise operational applications of these systems in various industries. New researches are now focused on operational problems of BTFs such as clogging problems, due to excess biomass or elemental sulfur accumulation on the packing material.

Keywords:

Biotrickling filter , Biofilter , Pall ring , Biofilm , Compost , VOC