Microalgae-assisted heterotrophic nitrification-aerobic denitrification process for cost-effective nitrogen and phosphorus removal from high-salinity wastewater: Performance, mechanism, and bacterial community

• Published in: Bioresource technology 2023-12, Vol.390, p.129901-129901, Article 129901
• Main Authors: Zhang, Linfang, Huang, Xiaodan, Chen, Wenting, Fu, Guokai, Zhang, Zhi
• Format: Article
• Language: English
• Subjects: Algal-bacterial symbiotic system; ammonia; bacterial communities; biofilm; Biologically induced phosphate precipitation; cost effectiveness; denitrification; Energy balance analysis; energy flow; metabolism; microalgae; nitrogen; phosphates; phosphorus; technology; Thauera; wastewater; Wastewater treatment, Nutrient removal mechanism
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2023.129901

[Display omitted] •Efficient N and P removal was realized by the microalgae-assisted HNAD system.•The biological removal process contributed 55.3–71.8 % of nitrogen removal.•BIPP undertook approximately 45.6–51.8% of phosphorus removal.•Microalgae might induce the development of photosynthetic bacteria in biofilm.•The microalgae-assisted HNAD system was energy self-sustaining. A microalgae-assisted heterotrophic nitrification-aerobic denitrification (HNAD) system for efficient nutrient removal from high-salinity wastewater was constructed for the first time as a cost-effective process in the present study. Excellent nutrient removal (∼100.0 %) was achieved through the symbiotic system. The biological removal process, biologically induced phosphate precipitation (BIPP), microalgae uptake, and ammonia stripping worked together for nutrient removal. Furthermore, the biological removal process achieved by biofilm contributed to approximately 55.3–71.8 % of nitrogen removal. BIPP undertook approximately 45.6–51.8 % of phosphorus removal. Batch activity tests confirmed that HNAD fulfilled an extremely critical role in nitrogen removal. Microalgal metabolism drove BIPP to achieve efficient phosphorus removal. Moreover, as the main HNAD bacteria, OLB13 and Thauera were enriched. The preliminary energy flow analysis demonstrated that the symbiotic system could achieve energy neutrality, theoretically. The findings provide novel insights into strategies of low-carbon and efficient nutrient removal from high-salinity wastewater.