Ammonia volatilization from a piggery pond

There is a need to improve the performance of agricultural wastewater stabilization ponds. In particular, a better understanding of the relative importance of the nitrogen removal mechanisms is required. The objective of this study was to quantify the magnitude of ammonia volatilization from a piggery pond in order to determine its significance as a nitrogen removal mechanism. A model of a typical piggery pond was established and sampled for ammonia, TKN, COD and pH. A method was developed to allow the rate of ammonia volatilization to be quantified. The rates of ammonia and total nitrogen removal were established, as were the corresponding COD and pH levels over a series of pond ammonia concentrations. The rate of ammonia volatilization ranged from 355 to 1534 mg/m2.d, increasing with higher concentrations of ammonia and TKN. These rates compared well with volatilization rates from other types of piggery waste disposal. It was concluded that although it is impractical to use ammonia volatilization in its own right to achieve high levels of nitrogen removal, it does make a significant contribution to the overall nitrogen removal potential of a piggery pond system.