Adaptation of an ammonia volatilization model for a naturally ventilated dairy building

Abstract

A theoretical ammonia emission model was adapted to the conditions prevailing in a naturally ventilated dairy building. The relevant parameters including the mass transfer coefficient needed for the model were experimentally measured. Ammonia emissions from the dairy building were also calculated from directly measured ammonia concentrations and carbon dioxide mass balances from the dairy building. The results of the theoretical model for ammonia emission from manure were compared with the experimentally measured emissions inside the dairy building. The absolute mean difference and standard error between ammonia emissions from the theoretical model and the experimental measurements was 0.013±0.005 g m−3 h−1. Parametric inaccuracy range in both emission estimation methods was 40%. A factor of ten difference was recorded between day and night ammonia emission rates. Ammonia emissions varied between 0.04 and 0.58 g m−2 h−1. The critical parameters that need to be considered in reducing ammonia emissions in dairy buildings according to the theoretical emission model were manure temperature, pH and total ammoniacal nitrogen of the manure