Centrifugal pumps work by converting a rotational energy from a motor to induce a flow or raise the pressure of liquid. When a fluid enters from the suction end of the pump, the impeller catches the fluids and then rotates, making the fluid entering the pump rotate as well.
During this process, the fluid gains velocity and pressure as it leaves the impeller. A diffuser or scroll inside the pump then decelerates the fluid flow, further increasing the fluid pressure.
Since the rotational mechanical energy is transferred to the fluid, at the discharge side of the impeller, both the pressure and kinetic energy of the water will rise.