Removal of odor using biofilter from duck confinement buildings

Abstract

The poultry and waterfowl industry in the Fraser Valley of British Columbia needs to deal with odor emission problems. The objective of this study is to evaluate the performance of a pilot-scale biofiltration system for treating odors from the exhaust air streams of a commercial duck farm building before their release to the atmosphere. A pilot-scale biofiltration system with semi-enclosed wooden structure was designed, constructed and installed to treat the exhaust air from one of the 12 operating ventilation exhaust fans, having a ventilation rate of 2.36 m³/s. The empty bed residence time of the biofilter was 5–10 seconds at the design flow rate. The biofilter media comprised of 2 parts softwood chips and barks to 1 part finished compost. Fabric filters were used for pre-treatment to protect the biofilter from clogging by dust particles and feathers. Odor reduction was determined by measuring the concentration of the air entering and leaving the biofilter via olfactometry analysis. The odor concentration of untreated barn air was found to vary from 8553 ± 1006 to 12171 ± 1575 OU/m³; however, the odor concentration was substantially reduced to 420 ± 195 OU/m³ after the manure storage was cleaned out at the end of summer. The odor removal efficiency of the biofilter system averaged 95 ± 3%. The high frequency of cleaning and replacement required of the fabric filters would considerably increase the operating cost. Alternative methods of dust and odor removal that are more cost-effective will need to be investigated in the future.

Keywords:

• Odor removal
• biofilter
• duck farm
• olfactometry

Acknowledgments

The authors would like to thank Terry Sullivan and Simon Wen for their technical assistance. Thanks are extended to Bert Vane for his collaboration and support in the project. Special thanks to the air quality department of Greater Vancouver Regional District for making the instrument available for dust measurements. The advice of Rick van Kleeck and John Luymes at the Resource Management Branch of the B.C. Ministry of Agriculture and Food is much appreciated.