PARIS €19.24 (-0.21%)

Cercle des Nageurs de Marseille - France

Energy production from water networks: waste heat


Sustainably meet the heating and cooling needs of local authorities, developers, and building managers, which are all heavy energy consumers.


The customer's objective

The Cercle des Nageurs de Marseille wants to make major energy savings in heating its prestigious 3 000 m3 Olympic pool and pre-heating its domestic water, and it favours a 100 % renewable energy supply.


Veolia's solution

Recover the calories in wastewater through the proprietary Energido® process. By capturing unavoidable energy produced by urban facilities in the vicinity of the equipment (wastewater collection systems), fossil fuels can be replaced by renewable resources from a permanent (wastewater) rather than intermittent energy source (solar, wind, etc.).


The Energido® process allows some of the wastewater from a wastewater collection system (collector) to be diverted to a heat exchanger installed outside this network.

  1. Wastewater from the collector is pumped and directed to a heat exchanger. This spiral-shaped device, in which circulates brine (a heat conducting fluid), recovers approximately 5 °C by heat exchange.

  2. The cooled wastewater is returned to the network downstream of the collector.

  3. The heat exchanger is coupled to a new closed-circuit loop which supplies a water/water heat pump.

  4. The heat pump is in turn connected to two circuits: one maintains pool temperature at 27 °C all year and the other preheats domestic water to 35 °C before being heated to 55 °C by a gas boiler.

250 KW

Installed power to increase and maintain water temperature


Pool temperature maintained all year round

35 %

Savings on the annual energy bill



The infrastructure equipping the CNM generates 250 KW to heat the pool's water and maintain it at 27 °C all year round.

Thanks to this heat input, the heat pump connected to the system has an average efficiency of 1:5, i.e. for an energy consumption of 1 kWh, 5 thermal kWh of energy is produced.

Ideal for heating swimming pool water, Energido® is reproducible for a variety of uses, including heating and cooling homes and offices. Other aquatic centres, such as Aquarena in Arras or Aqualac in Aix-les-Bains, have already adopted the solution for their heating needs.

Customer benefits


Annual energy bill (gas and electricity) nearly halved

• Fossil fuel consumption reduced by 75 %

• Process eligible for the ADEME Renewable Heat Fund (up to 40 %) for installation costs and reduced VAT for the sale of heat



• 230 tonnes of CO2 avoided/year

• Replacement of energy from greenhouse gas-emitting fossil fuel with a renewable energy in a local loop.

Contract scope

Site: Cercle des Nageurs de Marseille

Population: 4 000 members including 150 top-level athletes

Equipment: Energido® process

Contract term

Since September 2013

Business sector



 Recovery of heat from the wastewater collection system


Energido® recovers a local renewable energy source - municipal wastewater - that is growing steadily due to urban development.

Energido® helps reduce greenhouse gas emissions by replacing fossil fuels with renewable energy sources and meets the objectives of the Territorial Climate and Energy Plans in place in the Urban Community of Marseille. 


Club des Nageurs de Marseille members and athletes enjoy water heated at a constant 27 °C all year round.