title: Granular activated carbon as nucleating agent for aerobic sludge granulation: Effect of GAC size on velocity field differences (GAC versus flocs) and aggregation behavior.
abstract: Initial cell aggregation plays an important role in the formation of aerobic granules. In this study, three parallel aerobic granular sludge reactors treating low-strength wastewater were established using granular activated carbon (GAC) of different sizes as the nucleating agent. A novel visual quantitative evaluation method was used to discern how GAC size affects velocity field differences (GAC versus flocs) and aggregation behavior during sludge granulation. Results showed that sludge granulation was significantly enhanced by addition of 0.2mm GAC. However, there was no obvious improvement in granulation in reactor amended with 0.6mm GAC. Hydraulic analysis revealed that increase of GAC size enhanced the velocity field difference between flocs and GAC, which decreased the lifecycle and fraction of flocs-GAC aggregates. Overall, based on analysis of aggregation behavior, GAC of suitable sizes (0.2mm) can serve as the nucleating agent to accelerate flocs-GAC coaggregation and formation of aerobic granules.
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Jia-Heng
authors.initials: JH
authors.lastname: Zhou
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Hu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
authors.forename: Hai-Tian
authors.initials: HT
authors.lastname: Yu
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Xu
authors.affiliation: Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Vidonish
authors.affiliation: Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005, USA.
authors.forename: Pedro J J
authors.initials: PJ
authors.lastname: Alvarez
authors.affiliation: Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China. Electronic address: felix79cn@hotmail.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhu
mesh_terms: D000332:Aerobiosis; D019149:Bioreactors; D002606:Charcoal; D012722:Sewage
chemical_list: D012722:Sewage; D002606:Charcoal
keywords: Aerobic granular sludge; Flocs–GAC coaggregation; Granular activated carbon (GAC); Hydraulic analysis; Nucleating agent