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E_OS images

  • © Christian Houdek

    E_OS pilot plant

    Comprehensive test series have delivered valuable results that can be used for the E_OS large-scale plant. © Christian Houdek

  • © LBS/Open Brand Design

    Focus on energy:

    As of 2020, ebswien hauptkläranlage converts into an eco-power plant. © LBS/Open Brand Design

  • © Christian Houdek

    E_OS pilot plant:

    Commissioning ceremony with Environment City Councillor Ulli Sima and Christian Gantner, Director General of ebswien. © Christian Houdek

  • © Felicitas Matern

    EIA process:

    The E_OS Environmental Impact Assessment (EIA) documents submitted to the authorities filled as many as 220 folders! © Felicitas Matern

  • © Eva Kelety

    Groundbreaking ceremony for E_OS

    District Governor Eva-Maria Hatzl, Mayor Michael Häupl, Environment City Councillor Ulli Sima and Christian Gantner, Director General of ebswien (from right). © Eva Kelety

  • Kajak-Erstbefahrung in der Vorklärung West. © Christian Houdek

    Dichtheitsprüfung:

    Zur Qualitätskontrolle sind die Becken mit Reinwasser gefüllt. © Christian Houdek

  • Tellerbelüfter und Rührwerk in einem der neuen Belebungsbecken. © Christian Houdek

    Belebung:

    Tellerbelüfter und Rührwerk in einem der neuen Belebungsbecken. © Christian Houdek

  • Zwischenklärbecken mit Kettenbandräumer in der ebswien hauptkläranlage vor Inbetriebnahme. ©  Christian Houdek

    Schräg:

    Kettenbandräumer in den neuen Zwischenklärbecken. © Christian Houdek

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City Councilor for the Environment and the Vienna City Utilities Ulli Sima

The wastewater treatment plant converts into an eco-power plant

Vienna sets a new standard with its project "E_OS – Energy Optimisation through Sludge Treatment", which will serve as a role model to many other countries around the world. Wastewater treatment plants are commonly among the major energy consumers in a community. Vienna's Main Wastewater Treatment Plant, for instance, consumes 60 GWh of electricity annually to clean all effluents produced in Vienna, corresponding to roughly one percent of Vienna's overall electricity consumption. By efficiently exploiting the energy contained in the sewage sludge, ebswien will be able to generate the entire amount of energy needed for wastewater treatment from its own sewer gas, a renewable fuel. Thanks to E_OS, the Main Wastewater Treatment Plant converts into an eco-power plant. This also significantly improves Vienna's climate footprint: the emission of CO2 equivalents is reduced by approximately 40,000 tonnes annually as of 2020. When accounting for the projected index increases, the overall cost of the E_OS project will be 250 million euros. Vienna remains prepared to invest in the environment - also in tough economic times.

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Clean wastewater. Clean energy.

Microorganisms provide in biological purification steps for waste water treatment.

More than 6,000 litres of wastewater - per second! - are processed at Vienna's Main Wastewater Treatment Plant. 20 hours later, the purified wastewater is discharged into the Danube, without impacting the river's water quality. To achieve such an excellent purification result, the Main Wastewater Treatment Plant devours roughly one percent of Vienna's overall electricity consumption. The lion's share of this energy - two thirds of the plant's overall consumption - is used by microorganisms to eliminate pollutants from the wastewater.

Energy has been a key focus of ebswien for many years. On the plant premises, solar energy, water and wind power are utilised and numerous measures to increase the plant's energy efficiency are implemented. Thanks to the subprojects carried out under SternE – "Strom aus erneuerbarer Energie" (electricity from renewable energy), electricity consumption has already been reduced by 11% or replaced by renewable energies. ebswien hauptkläranlage was one of the first Austrian companies that successfully passed the ISO 50001 certification audit and obtained a certificate for its energy management system in 2012. The project "E_OS Energy Optimisation through Sludge Treatment" takes us a giant leap forward: by using sewer gas as a renewable fuel, the entire energy needed for wastewater treatment will be produced on site as of 2020.

Space for climate protection

The tanks of the preliminary sedimentation and the first biological treatment stages have been continuously in operation since 1980 and have now reached the end of their service life. Necessary reinvestments in this section of the Main Wastewater Treatment Plant shall add energy efficiency, minimise the risk of downtime and reduce maintenance costs. The volume of the tanks located on the building site will be enlarged by 50 percent during the E_OS project. Since the aeration and intermediate sedimentation tanks will be much higher in the future, their base area will be significantly smaller. This frees up space for the new sludge treatment system - and thereby helps to protect the climate.

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E_OS Sewer gas helps to protect the climate

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Future
Climate
Environment

 

Sludge digesters were previously mainly used for stabilising and reducing sewage sludge, a “by-product” of wastewater treatment. The energy recovered during this process was more or less a "pleasant side effect". The initial focus of the E_OS project therefore was to maximise energy recovery. In collaboration with the Institute for Water Quality, Resource and Water Management at the Vienna University of Technology, ebswien hauptkläranlage developed an innovative process. Before the sludge enters the digester, it needs to be dewatered. The "thicker" the sludge, the more energy can be recovered. This rationale is based on the understanding that in order to be digested, the sludge as well as the water it contains need to be heated. If the water content is low, this will save energy. On the other hand, the sludge must not become too "thick" so it can still be pumped through the system. Comprehensive test series in the E_OS pilot plant have impressively confirmed our assumptions that ebswien is able to operate the new digesters using sludge with the double solids content than usual. This shows that smart ideas definitely help to produce more energy!

Thanks to the E_OS project, ebswien progresses from a major energy consumer to an energy-positive wastewater treatment plant. Over a one-year period, the plant is capable of producing more energy (especially electricity) than is needed for wastewater treatment (see diagram below). This significantly improves Vienna's climate footprint: CO2 equivalent emission goes down by approximately 40,000 tonnes annually, an amount produced when circling the globe by car 6,700 times!

Energy balance with E_OS

The diagram compares the energy demand of ebswien hauptkläranlage and the amount of energy produced by the sludge treatment facility after completion of the E_OS project: 63 GWh of electricity per year will be needed and 78 GWh of electricity per year will be generated. This surplus is even more pronounced in heat generation:the amount of heat generated (82 GWh) will be more than double the amount of heat consumed per year (40 GWh).

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E_OS News

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E_OS images

  • © Christian Houdek

    E_OS pilot plant

    Comprehensive test series have delivered valuable results that can be used for the E_OS large-scale plant. © Christian Houdek

  • © LBS/Open Brand Design

    Focus on energy:

    As of 2020, ebswien hauptkläranlage converts into an eco-power plant. © LBS/Open Brand Design

  • © Christian Houdek

    E_OS pilot plant:

    Commissioning ceremony with Environment City Councillor Ulli Sima and Christian Gantner, Director General of ebswien. © Christian Houdek

  • © Felicitas Matern

    EIA process:

    The E_OS Environmental Impact Assessment (EIA) documents submitted to the authorities filled as many as 220 folders! © Felicitas Matern

  • © Eva Kelety

    Groundbreaking ceremony for E_OS

    District Governor Eva-Maria Hatzl, Mayor Michael Häupl, Environment City Councillor Ulli Sima and Christian Gantner, Director General of ebswien (from right). © Eva Kelety

  • Kajak-Erstbefahrung in der Vorklärung West. © Christian Houdek

    Dichtheitsprüfung:

    Zur Qualitätskontrolle sind die Becken mit Reinwasser gefüllt. © Christian Houdek

  • Tellerbelüfter und Rührwerk in einem der neuen Belebungsbecken. © Christian Houdek

    Belebung:

    Tellerbelüfter und Rührwerk in einem der neuen Belebungsbecken. © Christian Houdek

  • Zwischenklärbecken mit Kettenbandräumer in der ebswien hauptkläranlage vor Inbetriebnahme. ©  Christian Houdek

    Schräg:

    Kettenbandräumer in den neuen Zwischenklärbecken. © Christian Houdek

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E_OS Construction works ahead

After the successful completion of the EIA process and the Europe-wide tender procedures, construction has been underway since 2015. The execution of the E_OS project is a huge logistic challenge  as the upgrade takes place while the wastewater treatment plant remains in operation. The quality of wastewater treatment in Vienna must be secured at all times. This results in a construction period of more than five years.

Overview of project milestones to date: 

 

2010ebswien hauptkläranlage receives mandate to prepare a feasibility study
2011ebswien submits positive feasibility study
2012E_OS project execution is unanimously approved by the Vienna City Council
2013Commissioning of pilot plant; Environmental Impact Assessment (EIA)
2014EIA process successfully completed; Europe-wide tender procedures
2015Groundbreaking ceremony and start of construction
2016Commissioning primary sedimentation west
2017Commissioning first biological cleaning stage (aeration tanks and intermediate sedimentation south)

 

 

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E_OS Videos

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E_OS Downloads

DownloadpfeilDownload pictures of E_OS project300 dpi jpg
Die ebswien hauptkläranlage nach Umsetzung des Projektes E_OS.

ebswien hauptkläranlage after completion of the E_OS project
© LBS/ebswien

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Rendering des Projekts E_OS in der ebswien hauptkläranlage.

E_OS project at ebswien hauptkläranlage - subject
© LBS/ebswien

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Grafik Projekt E_OS in der ebswien hauptkläranlage.

Diagram of E_OS project at ebswien hauptkläranlage
© LBS/ebswien

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Die E_OS-Versuchsanlage in der ebswien hauptkläranlage.

E_OS pilot plant
© PID/Christian Houdek

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