Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/5/2015
Publication Date: 5/5/2015
Publication URL: http://www.sbera.org.br/4sigera/files/1.9_MariaC.Garcia.pdf
Citation: Garcia, M., Vanotti, M.B., Szogi, A.A. 2015. Recovery of ammonia from anaerobically digested manure using gas-permeable membranes. In: Proceedings of the IV Symposium on Agricultural and Agroindustrial Waste Management, May 5-7, 2015, Rio de Janeiro, Brazil.
Technical Abstract: The gas-permeable membrane process can recover ammonia from wastewater with high nitrogen load, reducing pollution whilst converting ammonia into an ammonium salt fertilizer. The process involves manure pH control to increase ammonium (NH4) recovery rate that is normally carried out using an alkali. Different types of wastewaters can be used to recover nitrogen (N), among these wastewaters anaerobically digested swine manure (digestate) is one of those that contains more nitrogen. It is well known that high ammonia content in swine manure reduce biogas production by anaerobic digestion inhibition, being one of the reasons to use different substrates to co-digest with manure. Hence, if a large quantity of ammonia is removed during the anaerobic digestion process, inhibition caused by this compound will be minimized, improving anaerobic digestion and thus methane production. Moreover, final digestate pH is maintained around 7.7 to 8.0, which is convenient for the process or to incorporate in arable soils when the process is finished. As a result, the use of gas-permeable membranes to capture ammonia from digestates could be used to improve anaerobic digestion process and methane production. In this work we studied the recovery of nitrogen using gas-permeable membranes from anaerobically digested swine manure with nitrogen content of 4,293 milligrams of ammonium per liter. Results showed a total nitrogen recovery efficiency of 62 percent during the 32-day experimentation, and that the recovery rate was higher during the first 25 days of experimentation, with 71 percent of the nitrogen recovered.