Development of a low cost biofilter for swine production facilities

An experimental biofilter was built to treat exhaust air from a continuously running minimum ventilating fan that withdrew air from the manure pit under a farrowing barn. The low cost biofilter was constructed out of wooden poles laid on the ground and perforated plastic slats covered with a mixture of compost and kidney bean straw. Biofilter performance was monitored for nine months by measuring temperature, pressure drop, odor threshold, hydrogen sulfide and ammonia concentrations. A sprinkler system was added to add moisture during mild and warm weather. Average odor and hydrogen sulfide removal was between 75 and 90 percent. The cost of a proposed system for a breeding, gestation, and farrowing facility is estimated to $0.28 per piglet.