Effect of calcium addition to aerobic granular sludge systems under high (conventional SBR) and low (simultaneous fill/draw SBR) selection pressure

• Published in: Environmental research Vol. 194; p. 110639
• Main Authors: Barros, Antônio Ricardo Mendes, de Carvalho, Clara de Amorim, Firmino, Paulo Igor Milen, dos Santos, André Bezerra
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.03.2021
• Subjects: Aerobic granular sludge; Aerobiosis; Bioreactors; Calcium; Divalent cations; Nitrogen; Phosphorus; Selection pressure; Sequencing batch reactors; Sewage; Waste Disposal, Fluid; Aerobic granular sludge; Selection pressure; Divalent cations; Calcium; Sequencing batch reactors
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2020.110639

This paper investigated the effect of calcium addition on the formation and properties of aerobic granules under high (conventional SBR) and low (simultaneous fill/draw SBR) selection pressure. Additionally, the simultaneous removal of carbon, nitrogen, and phosphorus, and the operational stability were assessed. The conventional SBRs showed earlier granule development (20 days) than the simultaneous fill/draw SBRs. The effect of calcium on granulation was more accentuated in conventional SBRs, forming larger granules in a shorter interval of time due to the higher EPS production. Additionally, higher amounts of calcium were found in the EPS matrix, mainly during the formation of granules. The operation regime and the addition of calcium did not affect the removal of carbon, nitrogen, and phosphorus. However, they both influenced the granulation time, settleability characteristics, size, and granule composition. •Conventional SBR (CSBR) and simultaneous fill/draw SBR (SFDSBR) were studied.•CSBR showed earlier granule development (20 days) than SFDSBR.•The effect of Ca2+ on granulation was more accentuated in CSBR.•Higher amounts of Ca2+ were found in the EPS matrix of CSBR.•Operating regime and Ca2+ addition did not affect the removal of C, N, and P.