Wastewater treatment consumes large amounts of energy. At the same time, energy, nutrients and other valuable materials can be recovered from wastewater, recycled and reused. Around the world, wastewater treatment plants (WWTP) are transitioning to being engines of the circular economy, presenting an opportunity to accelerate innovations that support greater efficiencies and sustainability in the sector.

In Aarhus, the Marselisborg wastewater treatment plant (WWTP) has demonstrated that energy positive wastewater treatment is possible – reaching a staggering energy efficiency rate of 153%. The benefits, and opportunities, ahead are so great that a planned new plant will be named a resource plant, not a WWTP – Marselisborg ReWater. The new plant will be one of the case studies presented at NORDIWA, the Nordic Wastewater Conference, together with other examples of innovative wastewater management and treatment that can inspire water utilities to become resource stewards.

Energy and water linkages matter

The International Energy Association estimates that global electricity consumption will double within the next 25 years. Energy is as indispensable to water, as water is for energy production, and puts water at the centre of both Sustainable Development Goal (SDG) 6 on water and Goal 7 on providing clean energy for all. The water industry needs to rethink the way they operate if we’re to achieve both goals.

Pumping, treating and distributing water use up to 8% of global energy generation, and wastewater is the source of around 8% of total greenhouse gas emissions. The European Union has recognised the potential of wastewater services to contribute to its overall greenhouse gas reduction targets, alongside solid waste management and the open burning of waste.

Global figures demonstrate the strong link between water and energy. Water accounts for 4 % of global electricity consumption – equivalent to Russia’s annual electricity consumption. At city level, drinking water provision and wastewater treatment account for between 30 – 50 % of electricity bills. Without changes, this will only continue to grow with growing global demand for both water and energy.

In Denmark, this is not the case. The Ministry for Environment and Food reports that energy consumption in the water sector has declined by more than 20% over the last five years. The sector as a whole is moving towards energy neutrality, going from producing 12% of the energy it consumes to 27% today.

From wastewater treatment plant to resource recovery plant

Aarhus Water plans to make Marselisborg ReWater the world’s most resource efficient WWTP. The ambition is not only to meet the current and future requirements for treatment of wastewater, but to produce energy from the wastewater to make the supply of drinking water and wastewater treatment energy neutral.

Marselisborg ReWater will extract and utilize valuable resources from the wastewater that are currently considered as waste products. This ‘waste’ can be transformed into ‘green’ power, heating or fertiliser. Even today, the plant can produce surplus heat for the district heating network equivalent to the annual energy consumption of 500 households.

Innovation and research towards the circular economy is called for now

Aarhus Water knows that constructing the world’s most efficient WWTP cannot be achieved using today’s technologies and solutions. The intention is not to build a plant that stands unchanged for the next hundred years, but a plant that can be constantly improved, function as a test site for new or optimised treatment, and where resource recovery processes can take place. This is why an important element in the construction of Marselisborg ReWater is the development of a new innovation strategy including 15 innovation challenges to be addressed – and further developed – in the coming years.

One water utility cannot solve all the challenges on its own. Aarhus Water is inviting companies, knowledge institutions and citizens to work with them to develop Marselisborg ReWater into the future.

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Learn more and see for yourself at NORDIWA – The Nordic Wastewater Conference, 10 – 12 October, 2017

NORDIWA is a collaboration between the Nordic water and wastewater associations and the Nordic IWA national committees. The program committee has representatives of Aarhus Water, Technical University of Denmark, Aalborg University, Aarhus University and DANVAs sister organizations from Norway, Sweden, Finland and Iceland as well as DANVA.

More information here: www.nordiwa.org

Registration is open, but please note that the Early Bird discount rate ends on August 31, 2017.

A technical tour to the existing Marselisborg WWTP will be organised.