Wastewater management is seen as an important environmental problem faced by the developing countries. Untreated wastewater has serious effects on human health and natural environment. For this reason, selection of the appropriate wastewater treatment (WWT) alternative is vital for sustainable development. The aim of this paper is to propose a fuzzy multi-criteria decision making (MCDM) approach based on 2-tuple fuzzy linguistic representation model, decision making trial and evaluation laboratory (DEMATEL) method and fuzzy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method. The weights of criteria considered for alternative evaluation are calculated by decision making trial and evaluation laboratory (DEMATEL) method, and then fuzzy TOPSIS method is used to rank the alternatives. The proposed framework enables managers to deal with multi-granular information, and thus, allows for the use of different semantic types by decision-makers. The application of the proposed methodology is illustrated through a case study for evaluation of wastewater treatment alternatives.