Ozone Treatment of Slurry - New Method for Reducing Odour from Swine Production Units

Abstract

When treating swine slurry with ozone, the slurry is divided into fractions. It is divided into a thin fraction, a thick fraction, and a foam fraction. This is used in connection with a brand new system for reducing odour from swine production units. Once a week, the slurry in the pits is flushed into a concrete tank. The slurry is then pumped into a treatment facility located in a container outside the swine production unit. The slurry is treated with ozone in two steps. In the first step, ozone is quickly added to the slurry, after which the slurry is divided into a thin fraction and a thick sediment fraction. The thin fraction is again treated with ozone, resulting in a layer of foam at the top of the treatment tank. The thin, relatively clarified fraction is then returned to the pit in the production unit, while the foam fraction and the thick fraction are pumped into the manure storage facility. The odour and ammonia emissions from two identical sections in a finishing unit were compared. The slurry in one of the sections was treated as mentioned above. Two batches of finishers were included in the experiment and, on 10 measurement days, odour measurements were taken in the outlets of the two sections at 11 a.m. and 1:30 p.m. The slurry treatment system significantly reduced the odour and ammonia emissions (P<0.05). The average odour emission was 490 OUE/s per 1000-kg animal from the control section and 240 OUE/s per 1000-kg animal from the section with the treated slurry. The ammonia concentration and the ventilation flow from the two sections were recorded on-line every two hours. There was no significant difference in ammonia emissions. The operating costs were 7.75 kWh/pig.