Evaluation of ammonia emissions from filtration of digestate used for fertigation

Fertigation can be a suitable technique for utilizing digestate, minimizing nitrogen losses, and contributing to circularity within farming system. For this purpose, digestate usually is first processed with screw-press separator. However, further filtration required remove particles that could clog the nozzles of drip or sprinkling irrigation systems. Advanced obtained using mechanical separation screens having openings 100- 300 μm. This operation another source ammonia emission, but aspect has not been adequately investigated. study aimed address knowledge gap by evaluating emissions from three different systems digestate. The was conducted in farms located Lombardy (Italy) fertigate maize (two farms) pivot (one farm). Ammonia were measured passive samplers fluxes examined an inverse dispersion model implemented Windtrax software. both when they switched off. (mean values between 375 876 μg NH3/m2/s) tended increase during no significant differences found active inactive equipment on any farms. higher than storage tank (22-67 NH3/m2/s). mean amounted only 0.3% content These considered irrelevant context whole management scheme work provides insight arising advanced specific reference Po Valley Further studies are improve about entire process, including treatments application techniques.