Domestic wastewater treatment covers the processes that used to treat waters that have been polluted by commercial or anthropogenic activities prior to its discharge into the environment or its re-use. Data Envelopment Analysis was applied to evaluate six urban wastewater treatment plants efficiency in three stages with fuzzy data and discretionary and non- discretionary inputs in Iran. Stream flow, Chemical Oxygen Demand and Total Suspended Solids were considered as input variables. In this paper a fuzzy network Data Envelopment Analysis model is proposed and solved with GAMS software. Results showed that showed that Bandar Torkman has the best performance between these waste water treatment plants and Babol and yasreb waste water treatment plants do not operate well. Manuscript profile

Performance measurement is always one of the most important tasks of managers, so knowledge management is measurement knowledge, and if we can measure something, we can no doubt control it, and therefore we cannot manage it. In this paper, according to the Malmquist productivity index, an index is used to determine the progress and regress of a unit. This index is defined by the boundary changes resulting from the inputs of the units and their efficiency changes, which we call the Malmquist Productivity Index. After calculating the Malmquist changes, we were able to determine the rate of increase or decrease in the indicators for the following period. Manuscript profile