Treatment of flue gas desulfurization wastewater by a coupled precipitation-ultrafiltration process

Yuanhui Tang; Yuanji Bai; Yakai Lin; Huanhuan Wu; Yang Hu; Lin Wang; Xiaolei He; Chunhui Zhang; Wenwen Sun; Xiaolin Wang

Results in Engineering (Mar 2023)

Treatment of flue gas desulfurization wastewater by a coupled precipitation-ultrafiltration process

Yuanhui Tang,
Yuanji Bai,
Yakai Lin,
Huanhuan Wu,
Yang Hu,
Lin Wang,
Xiaolei He,
Chunhui Zhang,
Wenwen Sun,
Xiaolin Wang

Affiliations

Yuanhui Tang: College of Chemistry and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, China; Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
Yuanji Bai: College of Chemistry and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, China; Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
Yakai Lin: Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China; Corresponding author.
Huanhuan Wu: Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China; Beijing International Scientific and Technological Cooperation Base of Water Pollution Control Techniques for Antibiotics and Resistance Genes, Beijing Key Laboratory of Aqueous Typical Pollutants Control and Water Quality Safeguard, School of Environment Beijing Jiaotong University, Beijing, 100044, China
Yang Hu: College of Chemistry and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, China
Lin Wang: Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
Xiaolei He: China Huaneng Clean Energy Research Institute Co., Ltd., Beijing, 102209, China
Chunhui Zhang: College of Chemistry and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, China
Wenwen Sun: College of Chemistry and Environmental Engineering, China University of Mining and Technology, Beijing, 100083, China; Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
Xiaolin Wang: Beijing Key Laboratory of Membrane Materials and Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China; Corresponding author.

Journal volume & issue: Vol. 17
p. 100938

Abstract

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Flue gas desulfurization (FGD) wastewater is characterized by low pH, high content of hardness ions and COD. In this work, chemical precipitation and ultrafiltration (UF) membrane separation were corporately coupled to treat the FGD wastewater on a lab scale to remove the hardness as well as some organic compounds for further advanced treatment. Firstly, influential factors for precipitation to deal with the simulated wastewater, including reaction time, stirring speed, and dosage, were investigated by batch tests, while CaO and Na2CO3 were used as the first and second precipitants. The batch results showed that the removal rates of Mg2+ and Ca2+ could be both higher than 98% under the optimal reaction condition. Then a polyvinylidene fluoride tubular UF membrane was used to remove the precipitates without adding flocculants. Thirdly, the coupled process with the optimal operation parameters was adopted to treat real FGD wastewater. Almost all the hardness ions and most COD could be removed, while rapid permeability decline was observed in the UF process due to the high COD, which could be recovered by a simple cleaning. In summary, when the mass ratios of [CaO]/[Mg2+] and [Na2CO3]/[Ca2+] were 2.5 and 2.7, the flow velocity was around 5 m/s, the removal rates of the hardness ions can be above 98% and the membrane flux can be recovered by 98% with a backwash with pure water and an HCl solution of pH = 2. This work proved that the coupled process is a technically feasible technology for treating FGD wastewater to realize the ZLD.

Published in Results in Engineering

ISSN: 2590-1230 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology
Website: https://www.journals.elsevier.com/results-in-engineering

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