This model simulates a water treatment plant that is driven by water demand. The plant uses up to 2 clarifiers that each have a known flow capacity. The treatment plant can operate at 2 different levels: 1 clarifier or 2 clarifiers in parallel. A water tank is used to regulate the treatment inflows and provide a steady supply to downstream water demands. The cost to operate the treatment plant is estimated as a function of treatment production rates over time.