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Water Res. 2017 May 15;115:210-219. doi: 10.1016/j.watres.2017.03.002. Epub 2017 Mar 2.

Seawater-based wastewater accelerates development of aerobic granular sludge: A laboratory proof-of-concept.

Author information

1
Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
2
College of Science and Engineering, Hamad bin Khalifa University, Education City, Doha, Qatar.
3
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.
4
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.

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.

KEYWORDS:

Aerobic granular sludge; Multi-ion impact; Rapid granulation; Seawater mixed sewage

PMID:
28282616
DOI:
10.1016/j.watres.2017.03.002
[Indexed for MEDLINE]

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