Evaluation of airflow through a horizontal-airflow biofilter with a non-pressurized headspace.

The control of odour from livestock barns continues to be an issue of importance for the livestock industry. A horizontal-airflow biofilter without a pressurized headspace was designed to eliminate problems that had been observed with a previous pressurized-headspace design. Seven distinct biofilter units were constructed adjacent to a commercial hog barn in southern Manitoba. Air velocity was measured across the top and side surfaces of each biofilter. Exit velocity was uniform across the sides, but more air exited through the top surface of the biofilter than was anticipated based on the design of the biofilter. Zeolite added to the biofilter medium (woodchip and compost mixture) enhanced the effectiveness of hydrogen sulfide reduction by up to 30% without negatively affecting airflow characteristics. [ABSTRACT FROM AUTHOR]