Environmental impact of pig production affected by wet acid scrubber as mitigation technology

Ammonia (NH3) is the most common air pollutant in pig farms, affecting animals and workers’ health, and causing damages to ecosystems. Hence, there is a need to reduce NH3 emissions. Many mitigation strategies can be applied to limit gaseous emissions, such as the application of air treatment technologies. In this study, the environmental impact of a typical Italian pig farm, adopting a wet acid scrubber to abate NH3 emissions, was evaluated using the Life Cycle Assessment approach. 1 kg of live weight (LW) was selected as Functional Unit. Two scenarios were considered. The baseline scenario (BS) represents the situation as it is, while the alternative scenario (AS) a wet scrubber prototype (with 70% NH3 removal efficiency) was adopted. For 8 of the 12 evaluated impact categories, AS shows the highest environmental impact, due to the scrubber construction and maintenance. However, it was the best for those impact categories most affected by NH3. Observed reduction ranged from 10% (for acidification, TA, and terrestrial eutrophication, TE) to 0.4% (for marine eutrophication, ME). The climate change impact was 3.55 kg CO2 eq kg-1 LW and 3.65 kg CO2 eq kg-1 LW for BS and AS, respectively. For almost all impact categories, the consumable materials for wet scrubber operation represented around 85% of the total impact of the scrubber. The results of the sensitivity analysis showed that variation in NH3 removal efficiency had the greatest effect on particulate matter formation, TA, and TE. The achieved results provide a first quantitative indication of the environmental benefits that can be achieved using wet acid scrubber in naturally ventilated pig facilities.