Anaerobic Fermentation of Substrate with High Nitrogen Content

N. Gróf and M. Hutňan

Abstract
This work focuses on anaerobic fermentation of synthetic substrate with high nitrogen content. An anaerobic continuously stirred tank reactor was gradually loaded with synthetic substrate, and the first inhibition was observed on day 110 when the SBP decreased by 20 %. Another significant change was observed on day 135, when SBP dropped to 122 L kg–1 COD. At the same time, a gas washing bottle with hydrochloric acid was connected to capture ammonia from recirculated biogas. With this arrangement, a slight increase in the SBP production to 150 L kg–1 COD was observed. On day 164, the gas washing bottle was changed to two gas washing bottles with fritted discs. After ten days, a significant increase in SBP, to 320 L kg–1 COD, was observed, indicating that the system began to overcome inhibition. From these results, it can be concluded that this method is effective in mitigating ammonia inhibition.

This work is licensed under a Creative Commons Attribution 4.0 International License

Keywords
absorption, ammonia inhibition, anaerobic digestion, CSTR reactor