Leibniz MMS Days 2023 - Abstract

Vu, Huyen

Modelling ammonia emissions from alkalizing dynamics of urine puddle pH in a solid floor naturally ventilated dairy cattle building

Urine puddle pH dynamics have been identified as one of the influential sources of ammonia emission rates in naturally ventilated housing systems. With a semi-empirical pH model, ammonia emission can be projected depending on urine alkalizing dynamics. An overestimation of emission values was observed when we set a constant pH and single exponential increasing pH in the whole curve with a hypothetical pHf =11. While simulations with double exponential increasing pH showed more realistic dynamic results during cold ambient temperature, associated with the alkalizing decline towards the asymptotic pH. With 18 settings of initial and asymptotic pH dynamics, the alkalizing process was more indicated by a late exponential decay at 2 and 10 hours. The effect of alkalizing dynamics based on the same set of pH parameters was investigated in reference correlations and predicted overall model accuracy.