An Investigation of Ammonia Extraction from Liquid Manure Using a Gas-Permeable Membrane

Abstract: Pollution of air, soil and water caused by excessive ammonia (NH3) emission and deposition from animal manure is as an environmental concern. Gas-permeable membranes (GPM) may provide a solution for controlling NH3 emission to the environment by extracting it from liquid manure and potentially using the recovered NH3 as fertilizer. For this purpose, four lab-scale experiments were conducted to investigate the capture and recovery of NH3 from liquid manure by circulating an acid solution through a tubular GPM submerged into the liquid dairy manure. During these experiments, the depth of liquid manure in chambers of different dimensions and the tubular membrane parameters including diameter, length and pore size were held constant in order to study the effect of acid-filled membrane on NH3 extraction from different surface areas (1X, 2X, 4X, and 8X) of liquid manure. Results show that nearly 50% of the liquid manure NH3 measured prior to the start of each experiment from all but 8X chamber was captured in less than 20 days by acid-filled membranes. Also, NH3 extraction by the GPM system from liquid manure and NH3 gain in acidic solution were linearly correlated. The study showed that the experiment with the 4X chamber resulted in optimum NH3 extraction using the GPM system.