The role of sulfate in aerobic granular sludge process for emerging sulfate-laden wastewater treatment

Weiqi Xue; Tianwei Hao; Hamish R Mackey; Xiling Li; Richard C Chan; Guanghao Chen

doi:10.1016/j.watres.2017.08.009

The role of sulfate in aerobic granular sludge process for emerging sulfate-laden wastewater treatment

Water Res. 2017 Nov 1:124:513-520. doi: 10.1016/j.watres.2017.08.009. Epub 2017 Aug 4.

Authors

Weiqi Xue¹, Tianwei Hao², Hamish R Mackey³, Xiling Li¹, Richard C Chan¹, Guanghao Chen⁴

Affiliations

¹ Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China.
² Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China; Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. Electronic address: thao@connect.ust.hk.
³ Division of Sustainable Development, College of Science and Engineering, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar.
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.

PMID: 28802136
DOI: 10.1016/j.watres.2017.08.009

Abstract

Sulfate-rich wastewaters pose a major threat to mainstream wastewater treatment due to the unpreventable production of sulfide and associated shift in functional bacteria. Aerobic granular sludge could mitigate these challenges in view of its high tolerance and resilience against changes in various environmental conditions. This study aims to confirm the feasibility of aerobic granular sludge in the treatment of sulfate containing wastewater, investigate the impact of sulfate on nutrient removal and granulation, and reveal metabolic relationships in the above processes. Experiments were conducted using five sequencing batch reactors with different sulfate concentrations operated under alternating anoxic/aerobic condition. Results showed that effect of sulfate on chemical oxygen demand (COD) removal is negligible, while phosphate removal was enhanced from 12% to 87% with an increase in sulfate from 0 to 200 mg/L. However, a long acclimatization of the biomass (more than 70 days) is needed at a sulfate concentration of 500 mg/L and a total deterioration of phosphate removal at 1000 mg/L. Batch tests revealed that sulfide promoted volatile fatty acids (VFAs) uptake, producing more energy for phosphate uptake when sulfate concentrations were beneath 200 mg/L. However, sulfide detoxification became energy dominating, leaving insufficient energy for Polyhydroxyalkanoate (PHA) synthesis and phosphate uptake when sulfate content was further increased. Granulation accelerated with increasing sulfate levels by enhanced production of N-Acyl homoserine lactones (AHLs), a kind of quorum sensing (QS) auto-inducer, using S-Adenosyl Methionine (SAM) as primer. The current study demonstrates interactions among sulfate metabolism, nutrients removal and granulation, and confirms the feasibility of using the aerobic granular sludge process for sulfate-laden wastewaters treatment with low to medium sulfate content.

Keywords: Granulation; Nutrients removal; Quorum sensing; Sulfate metabolism.

MeSH terms

Biological Oxygen Demand Analysis
Bioreactors
Sewage*
Sulfates / chemistry*
Waste Disposal, Fluid
Wastewater*

Substances

Sewage
Sulfates
Waste Water