$-----------------------------------------------------------------------------------------------------------1.$ There is an existing sewerage system with a centralized wastewater treatment plant $($Red square$)$ as given below. STP A node representslocalsitesfor grey water recycling Population at each node may comprise of a single or cluster of building even a small house. Possible location for decentralized Wastewater treatment and use We want to introduce in the above system the Decentralized Wastewater Treatment concept. The $$Blue$$ squares represent the possible locations where treatment plants can be set up$.$ The treated wastewater from the five WTTPs can be used for supplying water to a possible six $$industries$$ located in the project area i$.$e$.,$ the area covered by the sewerage system. It can also be exported to outside the project area through tankers$.$ You are required to determine the optimal sizing of these decentralized treatment plants. Formulate the possible optimization problem. You do not have to discuss about how to solve this problem: only the formulation of problem is required.