Aquarena Arras - VEOLIA’s photo library - Jean-François Pelegry

Energido heats swimming pools with wastewater calories

Posted on 28 October 2015.

Arras and Marseille heat their pools with a new power generation system – and wastewater replaces fossil fuels.

Energido uses the heat in wastewater to supply municipal swimming pools with a reliable source of 100% renewable energy.

In Arras, south of Lille, aquatic fun now comes in all shapes and sizes. Aquarena hides behind the waves of a transparent, colorfully lit façade. Completed in summer 2012, the complex houses an aquatic center, spa, hammam, sauna… There, each year approximately 240,000 visitors flock in a space of 4000 square meters of well-being and vitality! To heat the pools, an ingenious process has been developed - it recovers calories from the urban community’s wastewater.

Transferring wastewater calories to a heat pump

Veolia’s solution is called Energido and it’s really quite simple. Some of the wastewater from the urban area of Arras is diverted through a heat exchanger, which transfers heat from one fluid to another without mixing the two. The heat transfer fluid transports the calories recovered to a heat pump, which heats the water in Aquarena’s pools.

Less gas used means less CO2 emitted

The aquatic center is heated using a permanent, and therefore stable, source of renewable energy - unlike solar or wind power which are intermittent (they don’t consistently produce the same amount of energy). 75% of Aquarena’s annual energy needs are covered, which avoids the need for fossil fuels such as gas. The Energido system results in a 60% annual reduction in greenhouse gas emissions - the equivalent of 280 tons of CO2.

Gold medals also heated with wastewater

Particularly useful for buildings that require a lot of heat, this wastewater recovery process is also used in the very select Marseille circle of swimmers club (CNM). The pool - where champions such as Camille Lacourt and Florent Manaudou train - is kept at 27°C all year round. Reusing hot water from the showers saves 35% on the annual energy bill. 230 metric tons of CO2 emissions are avoided every year.