(Bio)electrochemical ammonium recovery from waste streams
14:00 - 14:30
Auditorium between bldg. 4 & 5, level 0
Conventional processes for ammonium removal are biological processes, like (de)nitrification and Annamox®. In both cases the ammonium is converted to nitrogen gas and all potential energy is lost. On top of that about 1-2% of ammonium will be discharged as N2O which is an unwanted strong greenhouse gas. Alternative treatment methods try to recover the ammonium as concentrated streams that can be reused, recovering the energy potential and preventing N2O emissions. But these alternative methods, like stripping, use a lot of energy.
We develop a new (bio)electrochemical way to concentrate the ammonium. The waste stream will enter the anode chamber, which is separated by a cation exchange membrane from the cathode chamber. Ammonium as positive ion will be transported to the cathode where it will be recovered by a hydrophobic membrane. Other cations like potassium and sodium will reach equilibrium between anode and cathode chambers. The energy input can be reduced in two ways. One uses bacteria that grow on the anode, that can produce a current based on the oxidation of organic compounds in the waste stream. One can recycle the produced H2 from the cathode to the anode. With this technology, we can recover ammonium at very low energy input. We will present the state of the art of this development.