Role of rotating speed on the stability of a self-sustaining algal-bacterial photo-granules process

• Published in: Bioresource technology 2022-06, Vol.353, p.127134-127134, Article 127134
• Main Authors: Shi, Wenxin, Feng, Xueli, Liu, Yi, Zhang, Bing, Lens, Piet N.L.
• Format: Article
• Language: English
• Subjects: Extracellular polymer substances; Nutrient removal; Photo-granules process; Rotating speed; System stability
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2022.127134

[Display omitted] •Performance of ABPG was improved when rotating speed increased from 120 to 140 rpm.•Low rotating speeds (120 and 130 rpm) resulted in slow bacterial growth in the ABPG.•Rotating speed of 140 rpm was optimal for the nutrient removal and system stability.•Increasing the rotating speed to 150 rpm caused the disintegration of ABPG.•The influencing mechanisms of rotating speed on the ABPG stability were revealed. The effects of rotating speed (120, 130, 140 and 150 rpm) of a photo-reactor on the self-sustaining algal-bacterial photo-granules sludge (ABPG) was investigated in this study. The ABPG process maintained good granular stability at 140 rpm with an integrity coefficient of 3.0% and excellent nutrient removal. The increases of the extracellular polymeric substances (EPS) content, the portions of α-helix (32.37%) in the secondary protein structure, and the relative abundance of functional bacteria (e.g. Candidatus_Competibacter), contributed to the maintenance of granular structure stability. However, the lower rotating speed (120 and 130 rpm) resulted in slow bacterial growth and reproduction while a higher rotating speed (150 rpm) caused the disintegration of photo-granules. Overall, the results reveal the influencing mechanisms of photo-reactor rotating speed on the self-sustaining ABPG process and provide an effective approach to maintain the system stability.