The performance efficiency of bioaugmentation to prevent anaerobic digestion failure from ammonia and propionate inhibition.

This study aims to investigate the effect of bioaugmentation with enriched methanogenic propionate degrading microbial consortia on propionate fermentation under ammonia stress from total ammonia nitrogen concentration (TAN) of 3.0gNL-1. Results demonstrated that bioaugmentation could prevent unstable digestion against further deterioration. After 45days of 1dosage (0.3g dry cell weight L-1d-1, DCW L-1d-1) of bioaugmentation, the average volumetric methane production (VMP), methane recovery rate and propionic acid (HPr) degradation rate was enhanced by 70mLL-1d-1, 21% and 51%, respectively. In contrast, the non-bioaugmentation reactor almost failed. Routine addition of a double dosage (0.6g DCW L-1d-1) of bioaugmentation culture was able to effectively recover the failing digester. The results of FISH suggested that the populations of Methanosaetaceae increased significantly, which could be a main contributor for the positive effect on methane production.