In anaerobic digestion only a part of the available organic material is converted into biogas. In this way the digestate still contains a significant amount of potentially degradable material. The application of disintegration techniques (e.g. AOP, ultrasonic) on the digestate and recirculating it to the digester can increase the total degradation potential significantly. Moreover, a high concentration of ammonia in the digester can be problematic for the stability of the system and can give rise to an inhibition of the micro-organisms. In this research disintegration techniques will be used to break down difficult biodegradable organic material and to oxidize the ammonia to nitrogen compounds that are less or not toxic for the micro-organisms. Also the microbial conversion of ammonia into nitrate (eg. by the anammox process), in which the nitrogen can be neutralized into N2 after recirculation to the anaerobic digester, will be investigated in this project. Besides that it will be examined if it is possible to recover the ammonia-nitrogen into a valuable mineral. The aim of this part of the research is to reduce the ammonia inhibition and thus increasing the biogas conversion by recirculation the digestate with a reduced nitrogen content into the digester.       

Vlakwa follows up this project as observer in the users’ committee.

Conducted in Flanders by:

• KULeuven – Technology campus De Nayer
• KULeuven – Technology campus Ostend
• University of Ghent

Running time: 1/10/2015 - 30/09/2017

More information: Lise Appels (lise.appels@cit.kuleuven.be)