Abstract
In our everyday lives, we collect water, use it and emit used water into the canal. We use water for drinking, sanitary, and washing purposes in our everyday lives. The amount of water we use for washing purposes is huge. In this paper we will propose a model in which we consider the refining process of water, which will produced for washing purposes. Unrefined water is harmful for the ecosystem of the river. If we emit our used water, which we used for washing purposes under refining, then this used water is not harmful for the environment. We also reused the refined water for our secondary purposes, such as vehicle washing, any construction purpose, in the dying industry, etc. We solve the model under the assumption that the availability of water at the supplying authority is uncertain. We find the cost without refinement, and then we calculate the cost with the refining process by using our proposed model. We compare these two results. Finally, we calculate the expected value of perfect information (EVPI) and the value of stochastic solution (VSS) by calculating the wait-and-see solution (WS), the recourse solution (RS), and the expected solution by using the expected first-stage decision (EEV).