Livestock activities are a major source of anthropogenic greenhouse gas emissions, particularly in tropical regions where high ambient temperatures accelerate manure degradation. This study evaluated the efficacy of field-scale continuous cattle slurry acidification using concentrated sulfuric acid (H2SO4) to mitigate methane (CH4) and ammonia (NH3) emissions under Malaysian conditions. Pilot observations in 600-liter high-density polyethylene tanks demonstrated that maintaining a slurry pH of 5.0 through periodic re-acidification reduced cumulative CH4 emissions by 62.3% and total NH3 volatilization by 35.3% over a 120-day storage period. A parallel field pond trial confirmed a 90% immediate reduction in CH4 flux following acidification to pH 5.0, though emissions gradually rebounded as the slurry’s natural buffering capacity returned the pH toward neutral. Economic analysis indicated the technology is viable with a Benefit-Cost Ratio (BCR) of 1.30, primarily driven by carbon (C) credit potential from CH4 mitigation, which accounted for over 80% of total benefits. However, the relatively modest net benefit indicates that the economic performance of the system remains sensitive to fluctuations in key market parameters, particularly carbon pricing and chemical input costs. These findings suggest that decentralized acidification is a practical tool for SME farmers to align with Net Zero 2050 targets, provided that policy interventions stabilize the economic returns against market volatility.
Keywords: Ammonia, cattle slurry, continuous acidification, greenhouse gas, methane
