One of the major goals of Québec’s Règlement sur les exploitations agricoles, REA is to prevent excessive soil enrichment of phosphorous. When used as the only nitrogen fertilizer to meet the soil requirements, pig slurry brings too much phosphorous to the soil. Complete manure treatment systems prevent this problem, but are expensive and require solid-liquid separation of the slurry. On the other hand, in-barn separation of pigs’ feces –below the slatted floor – produces a solid fraction high in phosphorous and dry matter content, and could reduce odours and greenhouse-effect gases. Three in-barn feces separation systems with regards to separation efficiency and air quality: the net, the V-shaped scraper and the conveyor belt have been compared. All three systems had a similar separation efficiency, concentrating more than 90% of phosphorous and around 50% of nitrogen within the solid fraction, which always contained a minimum of 30% dry matter. All systems equally reduced ammonia (NH3) by 50%, like the conventional scraper. Hence, the sole regular removal of feces from under the pigs seems as efficient as solid-liquid separation to lower NH3 emissions. Greenhouse gases (N2O and CH4), odour emission and the hedonic parameters were not modified significantly by the three systems.
In the field, spreading of the liquid fraction requires from 6,7 to 7,7 times less growing area. The installation of such systems would cost 66$ more per pig-place than the conventional system, but design optimization can reduce the costs.