Biofilters - The Influence of Different Filter Materials on the Reduction Efficiency

Abstract

The influence of five different filter materials on the reduction efficiency of biofilters has been investigated in parallel long-term measurements in a stall for fattening pigs. The greatest odour reduction (approximately 81%) was achieved with biochips and a mixture of coconut fibre and fi- bre peat as filter materials. All filter materials additionally reduce am- monia emissions by an average of about 9 - 30%. Biofilters with bio- chips caused considerably lower flow resistance and electricity con- sumption than filters with other materials. Biofilters allow odour emissions from farm animal husbandry to be re- duced by approximately 25 - 95%. Ammonia emissions also diminish to a certain extent (about 0 - 35%). However, very high operating expenses are attached to the use of biofilters if they are used properly (HARTUNG et al., 1997; HOPP, 1998; MANNEBECK, 1994). For this reason, they are used only when the minimum distance required by the VDI 3471 (1986) and VDI 3472 (1986) guidelines as well as the TA Luft (1986) (German Air Pollution Regulations) cannot be kept. The selection of the filter material provides a significant possibility to further optimize bio- filters.The present study was conducted to establish the odour reduction achieved by selected filter materials. Additionally, it was the goal of this research to examine the influence of the filter material on the reduction of the emission of NH3 , CO2 , CH4 , and N 2 O, as well as flow resistance and electricity consumption.