Organic contaminant removal from air - using bio-filter followed by filter stage or second bio-filter

摘要

In the purificn. of air contaminated with hydrocarbon cpds. and/or odours by passing the collected air through a biofilter. The biofilter has a size providing only partial decomposition of contaminants. The air leaving the biofilter is collected as a stream for complete decomposition of contaminants either by passage through a further correspondingly sized filter stage in the form of an adsorption or oxidn. stage or by combining with a second contaminated air stream passed through a second biofilter. The obtd. clean air is released to the atmos. Two air streams are pref. combined by combining the collected air stream from a biofilter, through which a small contaminated air stream passes, with either a large contaminated air stream to be passed through another biofilter, when its contaminant concn. is greater than that of the outlet air stream of this other biofilter, or the collected outlet air stream of this other biofilter, when its contaminant concn. is less than that of the outlet air stream of this other biofilter. USE/ADVANTAGE - The process is useful for treating air from solvent use, foundries, agriculture and agricultural product processing. Air of the requisite purity is produced at relatively low cost