The water treatment plant in Granville (France) receives raw water pumped from a river. The water is stored in an elevated reservoir before being treated at the plant. This means that the pipe that carries the water to the plant reaches a pressure of 1.2 bar.
Later, the water is stored in a pre-treatment tank. Therefore, a motorized valve is used to break the pressure of the raw water pipe and regulate the flow of entry to the plant.
This valve works partially closed, restricting the passage of water, which produces noise and wear on the valve itself.
The solution has been to install the turbine in bypass with the motorized inlet valve. It is a PAT (Pump used as Turbine) type turbine. In this way the valve remains closed and all the flow passes through the turbine to produce energy. The valve is only used during maintenance work on the turbine.
The generated power is 7kw working with a flow of 95 liters / second and a pressure drop of 1 bar. Therefore the efficiency of conversion of hydraulic energy to electrical energy is 75%.
Thanks to the installation of the turbine at the entrance to the water treatment plant in Granville (France), it is possible to generate 61,320 kwh / year. This energy is used in its entirety for energy self-consumption in the treatment plant itself. In other words, there is no excess energy to export to the electricity grid because the plant’s consumption is much higher. Therefore, important savings are achieved in the electricity bill for the purchase of energy, making the equipment pay for itself in a few years and generate important benefits throughout its life span.
The turbine in water treatment plant in Granville (France) is part of the European REDAWN project. This project’s main line of work is to improve energy efficiency in water distribution networks using water turbines.
Installation date: January 2020