renewable energy in the main wastewater treatment plant

© ebswien

Through the SternE project it was possible to reduce the annual CO2 emissions by 2,700 tons. At the same time the energy consumption of the main wasterwater treatment plant was cut by 11% or replaced by renewable energy.

The “Electricity from Renewable Energy” project (SternE) began in 2006 with the goal of making the main wastewater treatment plant in Vienna as independent as possible from traditional fossil fuel sources.

State-of-the-art wastewater treatment requires large amounts of energy. Wastewater treatment plants are directly dependent on the volume of wastewater and the degree of the wastewater contamination. The energy requirement can only be influenced by optimizing the wastewater treatment process.

Commitment to sustainability

Commitment to the highest possible level of energy efficiency began with the planning of the expansion of the main wastewater treatment plant in Vienna, which was approved in 2005.

63 GWh/a of energy would be necessary for optimum cleaning of Vienna’s wastewater. This corresponds to approximately 1% of the total energy requirement of the capital city. The topic of energy has been an ongoing focus of the ebswien company and their role as the wastewater treatment plant operator. In addition to the economic factors, corporate guidelines, which have committed to using the least amount of resources possible in support of sustainable environmental practices, provide the deciding factor.

Implementing partial projects

In 2006, the project “Electricity from Renewable Energy” (SternE) was launched. On the one hand, the ebswien main water treatment plant was committed to the continuing increase of energy efficiency at the facility. On the other hand, as a second step, the potential already in existence at the facility for renewable energy sources was to be optimized. The following SternE partial projects have already been implemented:

Since 2009, a Kaplan turbine installed in the wastewater treatment plant drainage area has been utilizing the existing drop to the Danube Canal for the creation of “clean” electricity.

A photovoltaic facility including a solar filling station for the E- vehicles of the city fleet and a solar thermal installation were put into operation in 2010.

A small wind turbine facility has been providing the energy required to light the 3, 5-kilometer long collector duct in the “cellar” of the main wastewater treatment plant since 2011.

This is the first time a hydroelectric turbine screw has been successfully put into operation in a wastewater treatment plant. As of 2013, additional hydropower potential in the discharge area is being utilized.

Measurable achievements

The emission of CO2 equivalents was reduced by approximately 2700 tons annually through the implementation of the SternE project. The energy usage of the main wastewater plants – assuming energy usage of 63 GWh in 2006 – was reduced by 11%/replaced by renewable energy sources.


Mag. Karl Wögerer

ebswien hauptkläranlage Ges.m.b.H.



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