Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 6/10/2015
Publication Date: 7/26/2015
Citation: Dube, P.J., Vanotti, M.B., Szogi, A.A. 2015. Enhanced recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membranes and aeration. In: Proceedings of the American Society of Agricultural and Biological Engineers International Meeting, July 26-29, 2015, New Orleans, Louisiana. doi:10.13031/aim.20152187787.
Technical Abstract: Atmospheric ammonia pollution from livestock wastes can be reduced using gas-permeable membrane technology by converting ammonia contained in the manure into ammonium salt for use in fertilizers. In this study, gas-permeable membrane technology was enhanced using aeration combined with nitrification inhibition to both increase the pH of the manure and the capture of ammonia by the membrane system. Two separate effluents from covered anaerobic lagoons with initial ammonia levels of 2089 milligram per liter (mg/L) and 1375 mg/L were tested using bench reactors of 1.5-Liter (L) effective volume. The aeration rate was low (180 milliliter per minute (mL/min) to prevent nitrification but sufficient to significantly increase pH. A control membrane manifold treatment without aeration was included in all the experiments. The pH of the manure with aeration rose from 8.6 to 9.2 while the pH of the manure without aeration decreased from 8.6 to 8.1. The total amount of ammonia removed using aeration was compared to the amount removed without aeration. With aeration, 97-99% of the ammonia was removed in about 5 days of operation. In contrast, it took about 25 days to remove the ammonia when aeration was not used. Therefore, the recovery of ammonia from digested effluent using the gas-permeable membrane technology was five times faster with the addition of low-rate aeration. This improvement represents a significant cost reduction in equipment for implementation of the technology.