Monitoring of NH3 and CH4 emissions from dairy cows under storage conditions

Cattle breeding is almost diffused around the world, with a growth of 7% in the last ten years. The increase in manure production makes cattle farms responsible for ammonia (NH 3 ) and methane (CH 4 ) emissions into the atmosphere. Many treatments have been adopted to reduce gaseous emissions, in order to comply with European regulations. Anaerobic digestion (AD) and solid-liquid separation (SLS) can modify the physical and chemical characteristics of manure, which are related to NH 3 and CH 4 emissions. The literature on the effect of the combination of both treatments on CH 4 and NH 3 emissions is still limited. Raw slurry (RS) and liquid fraction of digestate (LFD) were monitored during storage under controlled conditions, measuring NH 3 and CH 4 emissions with the dynamic chamber technique. The air sampled was analyzed using a gas-sensitive semiconductor and electrochemical sensors (Aeroqual, series 500). Results show that SLS and AD reduced the organic matter of manure, thus CH 4 emissions during storage, which accounts for 27% less than RS. On the other hand, AD increased the NH 3 emissions (48,5% more than RS) because of the higher Total Ammoniacal Nitrogen content of LFD. Only studying both gasses and considering the emissions in terms of CO 2 eq, it is possible to observe that RS is responsible for 11.4% of emissions in terms of CO 2 eq, more than LFD.