25 % of the world electricity consumption is made up of pumps. This rate increases to 70-80 % at public water supply authorities. Pumps are the biggest energy consumers in the water industry. Their energy consumption could lead to a significant decrease by choosing the right working point. The efficient working point can be defined by a regulated drive. The frequency switch, which is the latest tendency in controlling the pumps, can lead to an increased efficiency.
The two main section of pump use are drinking water and sewage disposal. Both sections have their own specific pumps and controlling system. In my thesis I will introduce the pumps used for drinking water and also for sewage. A description of their contolling system will be also given focusing on the newest frequency switches. To optimize the energy efficiency of the pump system, choosing the right pump, setting the controlling system and the frequency switches properly are essential. I will emphasize the importance of these issues in my thesis. The differences between the old and new systems in both sections will be shown by giving specific examples on saving energy.