The INNERS Project


Getting clean energy from waste water

The challenge

The search for renewable energy sources becomes more important as we face challenges like diminishing fossil fuel sources, increasing energy prices and stricter carbon emission limits. However, despite advances in this field over the past decade, the optimisation of the urban water cycle has not been focusing enough attention on its energy balance.

For example, more than 85% of the energy used in urban water systems goes into just heating household water. Since most of this water is still warm when discarded, the result is a missed opportunity to reduce energy, carbon emissions, and overall cost to consumers and businesses.

The project in brief

The INNERS project was organised to address this issue by an international group of universities, local authorities, water management institutions and 11 partners from the Netherlands, UK, France, Germany, Belgium and Luxembourg.

INNERS sought to tap the under-exploited potential of urban water systems, striving for an energy-neutral or even an energy producing urban water cycle. INNERS also looked for ways to optimise energy consumption and the reuse of energy from wastewater treatment plants.

Studying the energy consumption and production data from 350 plants in North-West Europe, the INNERS team believed that the source of “blue energy” that is present in the urban water cycle can significantly contribute to addressing these challenges, while at the same time working towards the Europe 2020 carbon reduction targets.

 

This sustainable heating system can now be easily reproduced due to the ease of installation and the innovative use of existing waste-management infrastructure.

The impact

The studies and pilot programs completed through the work of INNERS proved that recovering heat from waste water is feasible in a short amount of time, with a quick payback in energy savings and CO2 reductions. Importantly, this sustainable heating system can now be easily reproduced in other locations in North-West Europe due to the ease of installation and the innovative use of existing waste-management infrastructure.

For example, in Raalte, the project managed to recover energy from a nearby wastewater plant to heat the local swimming pool. This allowed Raalte to use 33% less gas and save 137 tons of CO2 and €25 000 per year.

Other project pilots applied different techniques to recover energy. In Leuven, Belgium, the heat recovered from the sewer system allowed the heating of 93 apartments. INNERS also developed innovative solutions for the waste water treatment plants, for example in Wuppertal-Buchenhofen in Germany, by connecting the sludge incineration plant with the existing heat grid. In Dewsbury, UK, INNERS recovered heat from the storm water soil infiltration system and used it to heat 3 homes.

These factors combined, this project has the potential to impact energy savings and carbon emissions throughout Europe, and stakeholders from France, Germany, and Sweden have already shown interest in expanding outside of the 11 original partners.

 

In Leuven, Belgium, the heat recovered from the sewer system heated 93 apartments.

93

Apartments heated in Leuven, Belgium with recovered heat

25 000

Euros/year saved with recovered heat

7

Completed pilot facilities

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