Document Type : REVIEW PAPER


1 University of Sri Jayewardenepura, Gangodawila, Nugegoda, Sri Lanka

2 Nagaoka National Institute of Technology, Nishikatakai, Nagaoka, Niigata, Japan

3 Ichinoseki National Institute of Technology, Takanashi, Hagisho, Ichinoseki, Iwate, Japan



Natural waterways are contaminated due to industrialization, urbanization, population growth etc., degrading their quality. Contaminated waterways cause numerous health and environmental hazards. Therefore, it is imperative to remove contaminants. Coagulation is one of the efficient primary chemical treatment methods that could be used to treat such contaminants. Natural coagulants have gained popularity in the water and wastewater treatment industry due to their advantage over chemical coagulants. Natural coagulants are derived from either plants, animals, or microorganisms. This study has elaborated on the nature and mechanisms, and types of natural coagulants. In this review work, many studies have proposed several types of natural coagulants. However, plant-based natural coagulants extracted from different plant components have been extensively discussed and compared based on their application and efficiency in water and waste treatment. The primary purpose of this review is to refine the knowledge on the potential use and optimization of the effectiveness of eco-friendly and sustainable natural coagulants. Besides, the development efforts and the barriers reported by recent findings for the commercialization of natural coagulants are also discussed. Further, few modified natural coagulants have also been presented for exploring the other possible approaches to promote their usage in water and wastewater treatment in the future studies.

Graphical Abstract

Effectiveness of natural coagulants in water and wastewater treatment


  • Natural coagulants have been studied as an eco-friendly alternative for chemical coagulants;
  • Moringa olerifera, Chitosan, Tannins,  and Nirmali seeds, have been proven as effective coagulants for reduction of turbidity, COD and TSS etc.;
  • Natural coagulants have not yet been used in large scale commercial applications;
  • Natural coagulants can be used in conjunction with modifying agents.


Main Subjects

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©2022 The author(s). This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, as long as the original authors and source are cited. No permission is required from the authors or the publishers.

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