Arab J Sci Eng DOI 10.1007/s13369-016-2032-7 RESEARCH ARTICLE - CIVIL ENGINEERING Potential of Fuzzy-ELECTRE MCDM in Evaluation of Cyanobacterial Toxins Removal Methods Animesh Debnath 1 · Mrinmoy Majumder 2 · Manish Pal 1 Received: 11 March 2014 / Accepted: 18 January 2016 © King Fahd University of Petroleum & Minerals 2016 Abstract Cyanobacteria blooms and toxins released from cyanobacteria, called cyanotoxins, have become a serious environmental issue because of their potential toxicity to- ward human health. Several conventional and advanced water treatment methods are available for degradation of cyanotox- ins from surface water, but a cost-effective and efficient water treatment technique can greatly reduce the processing time and improve the quality of treated water. Selection of an op- timum treatment technique for cyanotoxins degradation is a multi-criteria decision-making problem owing to the involve- ment of several conflicting criteria and constraints. In this paper, an integrated Fuzzy-ELECTRE model was proposed and its potential toward evaluation of different cyanotoxins removal techniques has been explored to select the most suit- able technology. In this integrated model, criteria importance weights were determined by Fuzzy process, while the rank- ing of alternatives was performed using ELECTRE process. The result obtained from the model shows that ‘advanced oxidation by titanium dioxide (TiO 2 )’ is the most suitable technology among all considered technology for the removal of cyanotoxins. The developed methodological approach was also used to rank the available treatment techniques within the main group of conventional and advanced oxidation methods (AOMs). The results clearly depict that ozonation and pho- tocatalysis by TiO 2 are the best methods within the group of conventional and AOMs, respectively. The ability of the pro- posed model for providing complete and clear ranking of all B Animesh Debnath debnathanimesh@gmail.com 1 Civil Engineering Department, National Institute of Technology Agartala, Jirania, Barjala, West Tripura, 799046, India 2 School of Hydro Informatics, National Institute of Technology Agartala, Jirania, Barjala, West Tripura, 799046, India considered alternatives confirms its potential for evaluation of cyanotoxins removal methods. Keywords Cyanobacteria · Cyanotoxins · MCDM · Fuzzy-ELECTRE method 1 Introduction Cyanobacteria, also known as blue green algae, are the com- mon members of the phytoplankton groups of saline, brack- ish and freshwater body across the world [1]. Short time expo- sure to water containing cyanobacterial blooms may induce many moderate health problems (i.e., abdominal pain, vom- iting, diarrhea, irritation of skin and mucous membrane of the eyes, asthmatic attacks, muscle tremors, nausea, blurred vision, fever, hypoxia) to some serious health hazards (i.e., paralysis and respiratory or cardiac arrest) and even death [1–4]. Moreover, cyanobacteria produce taste and odor com- pounds and also have the ability to produce lethal toxic com- pounds, called cyanotoxins. Cyanobacterial hepatotoxins ap- pear to be the most widely distributed types of cyanotoxins in aquatic environment and microcystins (most commonly found microcystin variant is microcystin-LR) are most com- monly encountered in freshwater [5, 6]. Five cyanotoxins groups, namely microcystins, nodularin, cylindrospermopsin, anatoxins and saxitoxins, are of most significant in relation to water supplies [7]. Humans are potentially exposed to cyanotoxins through drinking water produced from raw wa- ter contaminated by cyanobacterial blooms. Most common adverse effects of cyanotoxins on human health include gas- troenteritis, cytotoxicity, liver damage and neurotoxic effects [8–10]. Health hazards of different cyanotoxins group and their permissible limits in drinking water are summarized in Table 1. 123