title: Seawater-based wastewater accelerates development of aerobic granular sludge: A laboratory proof-of-concept.
abstract: This study aimed to develop an aerobic granular sludge process for the efficient treatment of highly saline wastewater and understand the granulation process in a seawater-based multi-ion matrix. Five identical sequencing batch airlift reactors (SBARs) are used to treat synthetic saline sewage with different proportions of real seawater (0%-100%). The results confirm that aerobic granular sludge can be successfully developed with various proportions of seawater up to 100% and show that seawater not only significantly accelerates granulation but also generates stronger granular structures than does freshwater. The increased presence of gel-forming alginate-like exopolysaccharides in the granules explains why a greater proportion of seawater leads to higher density and improves the cohesive strength of the granules. SEM-EDX analysis further revealed substantial presence of both Ca2+and Mg2+phosphate in the granule core as well as in the outer layers providing extra bridging forces in addition to alginate-like exopolysaccharides for accelerating the granule formation and maintaining the structure. It is hoped that this work could explore another approach for saline sewage treatment and bring some clues for the mystery of granulation mechanism.
authors.affiliation: Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Xiling
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Jinghai
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Guo
authors.affiliation: College of Science and Engineering, Hamad bin Khalifa University, Education City, Doha, Qatar.
authors.forename: Hamish R
authors.initials: HR
authors.lastname: Mackey
authors.affiliation: Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Wastewater Treatment Laboratory, FYT Graduate School, The Hong Kong University of Science and Technology, Nansha, Guangzhou, China. Electronic address: thao@connect.ust.hk.
authors.forename: Tianwei
authors.initials: T
authors.lastname: Hao
authors.affiliation: Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Water Technology Center, The Hong Kong University of Science and Technology, Hong Kong, China; Hong Kong Branch of Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, The Hong Kong University of Science and Technology, Hong Kong, China; Wastewater Treatment Laboratory, FYT Graduate School, The Hong Kong University of Science and Technology, Nansha, Guangzhou, China.
authors.forename: Guanghao
authors.initials: G
authors.lastname: Chen
mesh_terms: D000332:Aerobiosis; D019149:Bioreactors; D012623:Seawater; D012722:Sewage / Q000737:chemistry*; D062065:Wastewater
chemical_list: D012722:Sewage; D062065:Wastewater
keywords: Aerobic granular sludge; Multi-ion impact; Rapid granulation; Seawater mixed sewage