Mitigating ammonia emissions for a sustainable livestock farming by advances in membrane technology and modelling tools

Abstract

With the agricultural sector contributing to 93 % of total ammonia emissions, the development of mitigation technologies is imperative for livestock farming. This study compared the nitrogen recovery performance of two novel gas-permeable membrane configurations: System 1 (S1), with external gas flow, and System 2 (S2), with internal gas flow. The influence of initial N concentration and exposure time on N recovery rates was investigated. The results established the markedly superior performance of S2, which achieved a N recovery rate of 237 g m⁻² d⁻¹, outperforming the 154 g m⁻² d⁻¹ rate of S1. This peak rate represents a 7-fold increase when compared to previous results. Mathematical models derived from regression analysis were developed for S1 and S2 and indicating that the theoretical maximum performance of S2 was 1.8-fold higher than that of S1 (Maximum N recovery rates of 155.65 and 281.2 g N m⁻² d⁻¹ for S1 and S2, respectively). The enhanced efficiency of S2 is ascribed to its internal flow configuration, which promotes a superior nitrogen mass transfer rate across the membrane. This design demonstrated greater robustness in managing high nitrogen loads, positioning it as a highly promising technology for practical implementation in livestock operations.