MicrobStopNH3

Ammonia is well known to inhibit the anaerobic digestion process. Many full-scale biogas reactors in Denmark, are seriously affected by ammonia toxicity, constantly loosing up to 1/3 of their methane potential. MicrobStopNH3 project proposes bioaugmentation with ammonia tolerant hydrogenotrophic consortia as a technical solution to tackle this problem. A preliminary investigation performed by DTU Bioenergy Group (ForskEL-10537), has shown that successful bioaugmentation of ammonia tolerant methanogenesis possible. However, the same study revealed that four scientific challenges have to be solved in order to achieve large-scale implementation of the bioaugmentation process. Specifically - a) identification of ammonia tolerant methanogenic mixed cultures to be used as bioaugmentation inocula (complex communities could have a greater impact on the process than a single microorganism), b) identification of the (critical biomass) (minimum necessary amount) of such ammonia tolerant inocula, c) identification of the optimal environmental and operational conditions to enhance the effect of such inocula, d) development of strategies for the upscale of this optimized process to pilot or full-scale reactors. These steps will lead to an innovative, reliable and stable bioaugmentation process that will enhance methane production up to 35 pct in large-scale biogas reactors suffering from ammonia toxicity.