Evaluating the Efficiency of Water and Wastewater Companies under Uncertainty by Using Interval Fuzzy Data Envelopment Approach (Case Study: Markazi Province)

Water and wastewater companies play a vital role in society as providers of drinking water services. Therefore, measuring the efficiency of these companies is an action that can help in the optimal allocation of water distribution among customers. Therefore, the present study was conducted to evaluate the efficiency of water and sewage companies in Markazi province. For this purpose, the interval fuzzy data envelopment analysis method was used. The basic premise of this method, unlike the traditional method of data envelopment analysis, is uncertainty about inputs and outputs. Given that uncertainties in the real world are inevitable, the need to use models that have the ability to control this uncertainty is strongly felt. Hence, a successful method is to use fuzzy data envelopment analysis method. The results of evaluation related to seventeen water and wastewater companies in Markazi province showed that Arak, Khomein, Delijan, Saveh, Komeijan, Mamooniyeh, Mahallat and Naragh by obtaining the efficiency range (0.83, 1),  have the highest level of technical efficiency. In addition, among the units under study, Ghargabad Water and Wastewater Company has the lowest level of technical efficiency with an efficiency range of (0.56, 0.46). There is also an excess of consumption over the research findings in the use of all inputs. Therefore, it was suggested that with the correct and optimal use of production inputs and less use of resources, the amount of efficiency can be improved to reach the efficiency frontier.