Ionic response of algal-bacterial granular sludge system during biological phosphorus removal from wastewater

• Published in: Chemosphere (Oxford) 2021-02, Vol.264 (Pt 2), p.128534, Article 128534
• Main Authors: Wang, Jixiang, Lei, Zhongfang, Tian, Caixing, Liu, Sen, Wang, Qian, Shimizu, Kazuya, Zhang, Zhenya, Adachi, Yasuhisa, Lee, Duu-Jong
• Format: Article
• Language: English
• Subjects: Acetate; Algal-bacterial aerobic granular sludge; Anion; Biological Products; Bioreactors; Cation; Nitrogen; Phosphorus; Phosphorus release; Sewage; Waste Disposal, Fluid; Waste Water
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2020.128534

Biological phosphorus removal (BPR) from wastewater can be generally realized through alternative non-aeration and aeration operation to create anaerobic and aerobic conditions respectively for P release and uptake/accumulation by polyphosphate accumulating organisms (PAOs), with P removal finally achieved by controlled discharge of P-rich sludge. In this study, the response of algal-bacterial aerobic granular sludge (AB-AGS) during BPR to main ions including Ac− (acetate), Cl−, SO42−, NH4+, K+, Mg2+, Ca2+ and Na+ in wastewater was investigated with conventional bacterial AGS (B-AGS) as control and acetate as the sole carbon source. Results show that BPR process mainly involved the changes of Ac−, K+, Mg2+, and Ca2+ rather than Cl−, SO42−, NH4+ and Na+. The mole ratio of ΔP/ΔAc kept almost unchanged during the non-aeration (P release) phase in both B-AGS and AB-AGS systems (ΔPB-AGS/ΔAcB-AGS > ΔPAB-AGS/ΔAcAB-AGS), and it was negatively influenced by the light in AB-AGS systems, in which 62% of acetate was not utilized for P release at the high illuminance of 81 k lux. During the entire non-aeration/aeration period, both ΔK/ΔP and ΔMg/ΔP remained constant, while ΔKAB-AGS/ΔPAB-AGS > ΔKB-AGS/ΔPB-AGS and ΔMgAB-AGS/ΔPAB-AGS ≈ ΔMgB-AGS/ΔPB-AGS. The presence of algae seemed not beneficial for PAOs to remove P, while more K+ and P uptake by algae in AB-AGS suggest its great potential for manufacturing biofertilizer. [Display omitted] •P release/uptake involved acetate, K+, Mg2+, and Ca2+ changes rather than others.•ΔP/ΔAc decreased in AB-AGS at high light density with >62% acetate not for PAOs.•ΔK/ΔP and ΔMg/ΔP ratios kept stable while were affected by illumination intensity.•Co-existing algae might mainly contribute to P removal at high light density.