NOM deteriorates water quality by forming taste, clarification, colour, and odour problems. It also increases coagulant and chlorine consumption which can initiate disinfection by-products harmful to human health. The coagulation-flocculation (CF) technique is an established method commonly employed to remove NOM in water treatment. Plant-based coagulant products (PCPs) derived from plants like the Moringa oleifera (MO) Strychnos potatorum Linn and Opuntia ficus indica, have been studied and proposed as sustainable alternatives to chemical coagulant, like, aluminium sulphate due to their abundant availability, low cost, low sludge volume and disposal cost, and biodegradability. This review paper provides an overview of the most widely studied plant-based coagulants and discusses their NOM and turbidity removal. It investigates recent analytical tools applied in their characterisation and floc morphological studies. The paper also investigates the effects of operating parameters such as coagulant dose, temperature, and pH, on NOM and turbidity removal. It also reviews up-to-date PCPs biophysical properties and CF mechanism and examines the efficiency of their extraction methods in reducing NOM. Finally, it discusses and suggests ways to overcome commercialisation draw-back caused by nutrient addition.
Bibliographical noteFunding Information:
The authors are grateful for facility support provided by the University of Birmingham UK. Award was from the Global Challenges Scholarship and School of Engineering Excellence Scholarships. Benjamin U. Okoro: Conceptualization, Methodology, Software, Formal analysis, Investigation, Data curation, Writing ? original draft. Soroosh Sharifi: Conceptualization, Supervision, Writing ? review & editing. Mike A. Jesson: Conceptualization, Supervision, Writing ? review & editing. John Bridgeman: Conceptualization, Writing ? review & editing.
© 2021 Elsevier Ltd
- Drinking water
- Organic matter
- Compounds extraction and purification
ASJC Scopus subject areas
- Chemical Engineering (miscellaneous)
- Waste Management and Disposal
- Process Chemistry and Technology