Patents
This invention relates to a biological filter for the purification of waste gases emanating from tanneries that contain compounds such as ammonia, hydrogen sulfide and volatile organic compounds such as, benzene, toluene and xylene by passage through a porous bio-active solid media. The media comprises a combination of natural and synthetic materials containing micro-organisms which convert the contaminant compounds to oxidised products, thereby effecting the desired purification. Biofilter system configured in the innovation is capable of achieving higher removal rates of odour causing compounds in tannery with lower Empty Bed Residence Time (EBRT) than conventional biofilter systems. The design of the system is very novel in the sense that contaminated air and nutrient or water dosage is in co-current fashion so that normal moisture content required for the biofilter is always maintained even at the bottom part of the filter.