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The search for possibilities to save energy and find new energy production opportunities is an important aspect in discussing the climate protection. Up to now, the heat which is stored in wastewater is not used. Wastewater heat recovery offers a resource saving, clean and cheap option of energy production in urban areas. In this thesis the function and structure of wastewater treatment plants are represented as well as the state of art of wastewater treatment in Austria and Finland. Furthermore, the possibilities of energy production and their impacts and costs in sewage plants are explained. The sewage plants in Helsinki and Turku are the first two wastewater treatment plants which use heat pump stations to produce energy. Austria has a big capacity in recovering heat from wastewater. According to the state of art, there are three possibilities of energy production from wastewater. Furthermore, environmental topics of the oil and gas industry are included as a sepearte part in this book g.e. cost of environmental incidents, impacts of produced water, biodiversity and water footprint.

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Katharina Karner holds a degree in Energy and Transport Management. She is currently working as research assistant at the University of Applied Sciences Joanneum in Kapfenberg.

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