Magnetite enhancing sludge anaerobic fermentation to improve wastewater biological nitrogen removal: Pilot-scale verification

Chemosphere. 2023 Jun 12:139197. doi: 10.1016/j.chemosphere.2023.139197. Online ahead of print.ABSTRACTAlkaline anaerobic fermentation for acids production has been considered as an effective method to recover resources from waste activated sludge, and magnetite could improve the quality of fermentation liquid. Here we have constructed a pilot-scale sludge alkaline anaerobic fermentation process enhanced by magnetite to produce short chain fatty acids (SCFAs), and used them as external carbon sources to improve the biological nitrogen removal of municipal sewage. Results showed that the addition of magnetite could significantly increase the production of SCFAs. The average concentration of SCFAs in fermentation liquid reached 3718.6 ± 101.5 mg COD/L and the average concentration of acetic acid reached 2368.8 ± 132.1 mg COD/L. The fermentation liquid enhanced by magnetite were used in the mainstream A2O process, and the TN removal efficiency increased from 48.0% ± 5.4%-62.2% ± 6.6%. The main reason is that the fermentation liquid is conducive to the succession of microbial community in the denitrification process, increasing the abundance of denitrification functional bacteria and realizing the enhancement of denitrification process. Besides, magnetite can promote the activity of enzyme to enhance biological nitrogen removal. Finally, the economic analysis showed that magnetite enhancing sludge anaerobic fermentation was economically and technically feasible to promote bio...

Source: Chemosphere - June 14, 2023 Category: Chemistry Authors: Binbin Jiang Donghui Lu Xiaojia Shen Fan Zhang Xiangyang Xu Liang Zhu Source Type: research