How does THP fed anaerobic digester react to increased ammonia concentration?

摘要

Five CSTR lab scale mesophilic Anaerobic digesters (AD) were operated to investigate the impact of the increased ammonia concentration to the thermally hydrolyzed sludge fed AD. Ammonia bicarbonate were used to manipulate the digester ammonia level. A significant biogas production drop was observed when digester free ammonia level reached approximately 800 mg N/l. However, part of the deficit biogas production was able to be recovered when long enough acclimation time was given. It was found that the required recovery time was shorter when the ammonia concentration ramp-up speed was slower. Results also shown that digesters operated at approximately 1150 mg N/L was producing 12% lower biogas when compared to the digesters operated at below 700 mg N/L FA. This study also suggested that ammonia toxicity was mainly negatively impacting methanogenesis within AD.