Dual inner circulation and multi-partition driving single-stage autotrophic nitrogen removal in a bioreactor. (July 2022)

• Record Type: Journal Article
• Authors: Chen, Hong; Yang, Enzhe; Tu, Zhi; Wang, Hong; Liu, Ke; Chen, Jing; Wu, Sha; Kong, Zhe; Hendrik Sanjaya, Eli; Yang, Min
• Is Part Of: Bioresource technology. Volume 355(2022)
• Publication Date: 2022-07
• Subjects: Autotrophic nitrogen removal -- Anammox -- Multi-partition -- Dual inner circulation -- Airlift; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2022.127261
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: An NRR of 0.85 kg-N/m 3 /d was obtained by a PNA-AIPBR with 250-mg NH4 /L influent. The TNRE of the PNA-AIPBR increased to > 85% within 38 days. Dual inner circulation and aeration regulation are crucial for nitrogen removal. Spatial distribution of autotrophic N removal biochemical reaction was optimized. Dual inner circulation/multi-partition promote AOB and AnAOB enrichment/synergism. Abstract: The single-stage autotrophic nitrogen removal (ANR) process is impeded by a long start-up cycle and unstable operation performance. In this study, an airlift inner-circulation partition bioreactor (AIPBR) was operated continuously for 215 days to explore methods of strengthening the performance and stable operation of the single-stage ANR system. AIPBR start-up period took around 38 days, the total nitrogen removal efficiency was > 85% on day 35. With the decrease of hydraulic retention time and the increase of aeration rate, the nitrogen removal rate increased to 0.85 ± 0.02 kg-N/m 3 /day. The sludge morphology gradually changed into dark-red floc-coupled granular sludge. Nitrosomonas (9.95%) and Candidatus Brocadia (6.41%) were dominant in the sludge. During long-term operation, AIPBR achieved the dual inner circulation of sewage and sludge and then formed effective dissolved oxygen and sludge partitions to provide a suitable growth environment for various functional bacteria, promote synergy between them, and strengthen the ANR performance.