Enhancing autotrophic nitrogen removal with a novel dissolved oxygen-differentiated airlift internal circulation reactor: Long-term operational performance and microbial characteristics. (15th October 2021)

• Record Type: Journal Article
• Authors: Wang, Hong; Yu, Guanlong; He, Weining; Du, Chunyan; Deng, Zhengyu; Wang, Dongbo; Yang, Min; Yang, Enzhe; Zhou, Yaoyu; Sanjaya, Eli Hendrik; Chen, Hong
• Is Part Of: Journal of environmental management. Volume 296(2021)
• Publication Date: 2021-10-15
• Subjects: Autotrophic nitrogen removal -- Anammox -- Dissolved oxygen -- Micro-granules -- Partition control; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2021.113271
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Autotrophic nitrogen removal (ANR) processes have not been widely applied in wastewater treatment due to their long start-up time and unstable performance. In this study, a novel dissolved oxygen-differentiated airlift internal circulation reactor was developed to enhance ANR from wastewater. During 200 days of continuous operation, the reactor start-up was achieved within 30 days; a high total nitrogen removal efficiency of 80% was achieved and stably maintained under an aeration rate of 0.90 L/min and hydraulic retention time of 6 h. Additionally, the color of sludge went from a light yellow to dark red, and the amount and size of the micro-granules increased obviously. Medium-sized (1.0–2.5 mm) micro-granules accounted for 72.4% on day 190. The specific anammox activity increased from 0.53 to 1.43 g-N/g-VSS/d, while the SNOA decreased from 0.93 to 0.08 g-N/g-VSS/d. Furthermore, the microbial analysis showed that the Nitrosomonas (4.2%) and Candidatus Brocadia (22.6%) were enriched and formed the micro-granules after the reactor's long-term operation. The results indicate that novel configuration realizes the partitioning of dissolved oxygen (DO), optimizes nitritation and anammox reactions, and accelerates biochemical reactions, thereby enhancing ANR performance. This study provides a practical alternative to enhance ANR performance and a scientific basis for the development and application of novel nitrogen removal reactors. Graphical abstract: Image 1 Highlights: A novel reactor for autotrophic nitrogen removal process was developed. A high TNRE of 80% was achieved and maintained stable. The effective partition of DO was realized. The functional bacteria were enriched and formed the micro-granules successfully. Partition control and granulation are effective pathways for enhancing performance.