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Research r...Environmen...Report number 0801

Report number 0801

Ozone treatment of slurry from finishers in climate chambers.


A trial was conducted in two climate chambers at Danish Pig Production’s experimental station Grønhøj. The two climate chambers were identical except for the fact that the company Bio-Aqua A/S was responsible for treating the slurry under the slatted floor in one of the chambers.

Each of the climate chambers comprised two traditional finisher pens with 16 pigs in each pen, and the trial was conducted twice with finishers weighing 30-110 kg.

The slurry treatment was started a few weeks after the finishers had been placed in the climate chambers. Once a week, the slurry was flushed into a tank located outside the building. The slurry was then pumped into a container where it was treated with ozone. During the treatment, the slurry was fractionated, and the thin, relatively clear fraction was returned to the slurry pits in the climate chambers, while the solid fraction was transferred to the manure storage area.

The odour emission from the two climate chambers with and without treated slurry was measured the day after the slurry had been in one of the chambers. The odour emission was statistically significantly lower from the climate chamber where the slurry had been treated with ozone. The odour emission was 490 OUE/sec. per 1000 kg pig from the control chamber and 240 OUE/sec. per 1000 kg pig from the chamber with the treated slurry.

On-line measurements of the ammonia concentration were performed using equipment from Veng System A/S, and the ventilation rate was measured using Fancom measurement wings throughout the entire production cycle. Based on the on-line data registrations, it could be concluded that the treatment strategy did not result in increased ammonia emissions from the section with treated slurry. It had been expected that the ammonia emissions could increase since ozone treatment results in a higher pH level and, consequently, in increased ammonia emissions. However, only the thin fraction with the lower nitrogen content was returned to the slurry pits, and therefore the higher pH did not result in increased ammonia emissions from the climate chamber.

There was a significant reduction in the emission of hydrogen sulphide from the chamber where the slurry had been treated with ozone compared with the control chamber, and the emission of practically every chemical compound measured by GC/MS and MIMS was reduced as a result of the treatment.

For one batch of pigs, 7 treatments were performed, resulting in an electricity consumption of 7.75 kWh/pig. With an electricity price of DKK 0.75 per kWh, this will result in an energy cost of DKK 5.80 per pig. Future trials will demonstrate the optimum number of treatments.

Furthermore, trials are currently being conducted in climate chambers where both ozone and a polymer are added. Infarm A/S has started to upgrade the pilot slurry treatment system so that it can be used on a commercial scale. The new system is called smellFIGHTER and will be tested by Danish Pig Production in the summer of 2008.

To read the full document in its entirety as a pdf file, please click here


Merete Lyngbye

Chief Project Manager

Tlf.: +45 3339 4361



Kristoffer Jonassen

Project Manager 

Tlf.: +45 3339 4345



Dorthe K. Rasmussen

Carsten Christophersen