Controlling Harmful Algal Blooms (HABs) by Coagulation-Flocculation-Sedimentation using liquid ferrate and clay

Abdullah Alshahri, Luca Fortunato, NorEddine Ghaffour, TorOve Leiknes

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


Harmful algal blooms (HABs) occur worldwide and threaten the quality of marine life, public health, and membrane facilities in Seawater Reverse Osmosis (SWRO) desalination plants. The effects of HABs on seawater desalination plants include extensive membrane fouling, increased coagulant consumption and plant shutdown. To determine how to mitigate such effects, this study assessed if low doses (0.01mg/L, 0.10 mg/L, and 1.00 mg/L) of liquid ferrate (58% yield) and kaolin or montmorillonite clays alone could remove algal organic matter in coagulation-flocculation-sedimentation (CFS) pretreatment desalination systems. Results showed that 0.01mg/L of liquid ferrate coagulant removed 42% of dissolved organic carbon (DOC), 52% of biopolymers (BP), 71% of algal cells, and 99.5% of adenosine triphosphate (ATP). At a dose of 0.01mg/L, clays exhibited high removal of turbidity (up to 88%), BP (up to 80%) and algal cells (up to 67%). The combination of liquid ferrate (58% yield) as a coagulant with kaolin or montmorillonite clays as coagulant aids in CFS pretreatment led to 72% removal of DOC, 86% of BP, and 84% of algal cells with a fixed dose of 0.01 mg/L for each. Findings from this study can help SWRO plants improve the performance of pretreatment systems during algal bloom events by reducing the consumption of coagulants while also maintaining high removal efficiencies.
Original languageEnglish (US)
Pages (from-to)129676
StatePublished - Jan 2021

Bibliographical note

KAUST Repository Item: Exported on 2021-02-21
Acknowledgements: The research reported in this paper was supported by funding from King Abdullah University of Science and Technology (KAUST). The authors acknowledge help, assistance and support from the Water Desalination and Reuse Center (WDRC) staff.


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