How to Reduce the Emission of Microorganisms from a Biofilter Used to Treat Waste Gas from a Food Industry Plant

Abstract

The aim of the study was to assess the bioaerosol removal efficiency by a semi-technical scale combined biofilter used to treat waste gas from a food industry plant. Two types of biofilter beds were tested: stumpwood chips and pine bark (CB) and stumpwood chips, pine bark and compost (CBC). Two types of membranes (covering the surface of the bed) were examined as the second stage of treatment: Pro Eko Tex UV (M1) and Pro Eko Tex UV 6 (M2). A conventional open biofilter (without membranes) was an emitter of microorganisms. There was no statistically significant difference between the number of bacteria emitted from CB or CBC beds, but fungal concentration was three times higher in gas treated by the CBC bed. The use of the membranes as the second stage of gas treatment significantly reduced the bacterial emission (74–78%) from the biofilter regardless of the bed and the membrane tested. The M1 membrane was also efficient in fungi removal from the treated gas by 80–97%. However, the M2 membrane could have been slowly colonized by fungi and have become an additional emitter of fungi in the system.