Response of algal-bacterial granular system to low carbon wastewater: Focus on granular stability, nutrients removal and accumulation

[Display omitted] •Highly structural stability of algal-bacterial AGS was maintained at COD/N = 1.•Algal-bacterial AGS has great potential for reducing GHGs emission.•98% of P bioavailability in algal-bacterial AGS was achieved at COD/N = 1.•Algal-bacterial AGS contained high P and N contents easily...

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Published in:Bioresource technology Vol. 268; pp. 221 - 229
Main Authors: Zhao, Ziwen, Yang, Xiaojing, Cai, Wei, Lei, Zhongfang, Shimizu, Kazuya, Zhang, Zhenya, Utsumi, Motoo, Lee, Duu-Jong
Format: Journal Article
Language:English
Published: England Elsevier Ltd 01-11-2018
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Summary:[Display omitted] •Highly structural stability of algal-bacterial AGS was maintained at COD/N = 1.•Algal-bacterial AGS has great potential for reducing GHGs emission.•98% of P bioavailability in algal-bacterial AGS was achieved at COD/N = 1.•Algal-bacterial AGS contained high P and N contents easily for resource recovery.•LB-EPS might be the key to stable algal-bacterial AGS at low influent COD/N ratios. The effect of influent chemical oxygen demand to nitrogen (COD/N) ratio on the granular stability, nutrients removal and accumulation of the algal-bacterial AGS was investigated. Two sequencing batch reactors were operated under different influent COD/N ratio, i.e., R1 (control, COD/N = 8) and R2: (COD/N = 8, 4, 2, and 1 through stepwise decrease of COD). Results showed that the integrity coefficient of the granules in R2 stabilized at 0.7–5.4% during the whole operation. Significantly enhanced dissolved inorganic carbon (DIC) uptake and the faster growth of algae indicated the great potential for reduction in greenhouse gases (GHGs) emission by using the algal-bacterial AGS system. The algal-bacterial AGS biomass contained high phosphorus (P) and N contents as well as extremely high P bioavailability (up to 98%) which could be easily used for resource recovery. Loosely bound extracellular polymeric substances (LB-EPS) might be the key factor to control the deterioration of granular stability in this system.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2018.07.114