A Multicriteria Decision-Making Model for the Selection of Conventional/Hybrid Coagulants in Water Treatment.

Coagulation process is a well-known process that has been used in water treatment for many years. Coagulation process shows the treatment efficiency in terms of turbidity and suspended solids removal. However, despite all these good results, coagulant selection is not an easy task because a coagulant can effectively remove suspended solids but at the same time increase conductivity or coagulants can significantly increase chemical sludge production. The final selection of coagulants depends on the importance attributed to the parameter desired to be removed. In this study, the use of multi-criteria decision making (MCDM) is proposed to help select organic coagulants and hybrid coagulants, which have emerged as an alternative to inorganic coagulants in recent years due to the disadvantages of chemical coagulants and whose use and variety are increasing. Therefore, starting from the parameters determined by the coagulation process results, these techniques will allow weighting these parameters according to the judgments of drinking water treatment plant professionals and determining priorities among coagulants. The agreement between the obtained results and the literature shows that the AHP method is a useful tool for selecting coagulants. According to the results of the AHP matrix created with 4 criteria and 9 alternatives, it has been observed that hybrid coagulants with similar performances to inorganic coagulants have not yet been adopted by drinking water treatment professionals. This may have been due to the higher price of hybrid coagulants and the fact that they are not yet widely used in the drinking water industry.