Gaseous emission from biological aerobic treatment (using an intermittent aeration) was compared with traditional manure management (based on 6 months storage before spreading). Using farm measurements and modelled estimations of slurry volume, flow rates and composition, annual emissions were estimated for 4 slurry management schemes (3 involving biological treatment and the fourth based on traditional storage/spreading) based on a farrowing-fattening farm with 200 sows. The results shows a large decrease of the greenhouse gases (methane and nitrous oxide) and ammonia (NH3) when using a biological treatment compared to using storage alone. The reduction was 30-52% for NH3 when the biological plant included mechanical separation and 68% when there was no separation. Greenhouse gases (CH4 and N2O) were reduced by about 55% whatever the composition of the biological treatment plant.