(46c) Membrane Distillation of Ammonia-Containing Wastewater and Utilization of Recovered Ammonia

Ammonia is a major pollutant in waste water discharged from livestock excreta treatment process. It is necessary to develop the suitable way to remove ammonia. We focused on a type of membrane distillation technique to remove ammonia from waste water. This technique consists of hydrophobic micro porous membrane and acidic absorption solution. In this system, ammonia gas vaporized from waste water diffuses into micro porous space of membrane, and then passed ammonia gas quickly dissolves in acidic solution at another side of membrane. Finally, ammonia was collected as ammonium ion in absorption solution. In previous research, inorganic acids (e.g. sulfuric acid, phosphoric acid) have been used as absorption solution. In this study, we carried out the membrane distillation experiment using supersaturated solution of fumaric acid as absorption solution. Polytetrafluoroethylene (PTFE) membrane was also used. As a result, it was found that ammonia removal was also possible by using fumaric acid, and ammonia was collected as ammonium fumarate. Ammonium fumarate has been used as a raw material of enzymatic amino acid production. Based on these results, we propose the novel process which is combined with membrane distillation and bioreactor to utilize recovered ammonia for amino acid production.