Harnessing the energy out of water and waste

Wastewater to heating

The Degrés Bleus solution combines a heat exchanger with a heat pump. The heat exchanger, comprising a closed-loop piping circuit, conveys the water that is warmed up by the heat in the wastewater. The water then reaches the pump, which performs the transition between the wastewater network and the heating circuit. The calories are then multiplied, so that the temperature of the water rises and it becomes usable. Degrés Bleus, does not cause any nuisances and is completely safe, it can be adapted to both new and existing networks in housing units, offices, hospitals, retirement homes, schools, etc….

Reducing CO₂ emissions by 300-tons a year

By producing green energy, Degrés Bleus cuts greenhouse gas emissions by 50% to 70% compared with traditional thermal solutions. It preserves the planet’s natural capital by reducing the consumption of non-renewable energy by 30% to 60%.

It’s in use in 20 sites in France

It was first used in 2010, at the Aquatics Centre in Levallois-Perret. Degrés Bleus is now used in Bordeaux (Administrative offices), Valenciennes (Town Hall), Paris (the Elysée Presidential Palace; the Wattignies School site and the “Aspirant-Dunand” pool complex), Nanterre (St. Genevieve eco-district), Dijon (Dijon council’s TRAM depot), Maubeuge (University campus), Mulhouse (Lefebvre barracks), Marseille (“Les nouveaux Chartreux” apartment block), Saulx-les-Chartreux (SIAHVY mill) and Annemasse (swimming pool).

In Strasbourg, France, where SUEZ operates the wastewater treatment station, we’ve teamed up with Réseau GDS, the local natural gas distributor, in the innovative BIOVALSAN project. This project consists of injecting biomethane produced from wastewater into the natural gas network. Today, it produces 1.6 million Nm³/year of purified methane, or the equivalent of the consumption of 5,000 low-consumption housing units, which is injected into the city’s existing natural gas network. BIOVALSAN was supported by the European Commission’s LIFE+ program because  it has set an example for regional energy transition.

7,000 tons of CO₂ emissions avoided

BIOVALSAN has two-thirds of the CO₂ emissions from the La Wantzenau water treatment station, the fourth-largest in France.  Which treats the water for one million people. The combined optimization of the sludge treatment and of the recovery of the biogas as energy in the form of biomethane, means that the station now has one of the smallest environmental footprints in France. This new source of renewable energy has launched the transition towards a new local, sustainable and carbon-sober energy model in Strasbourg.

The BioGNVAL industrial demonstrator, installed on the SIAAP’s downstream purification site in Valenton, is the first of its kind in France to reuse the biogas from the treatment of wastewater as liquid biofuel (bioLNG), a renewable energy that is easy to store and transport. This biogas reuse solution consists of purifying the biogas, then liquefying it using cryogenic technology that divides its volume by 1,000. The resulting bioLNG (or liquefied biomethane) is made of almost 100% methane.

Reducing CO₂ emissions

The BioGNVAL project has now demonstrated that we can produce a clean fuel that does not emit any fine particles, makes 50% less noise and cuts CO₂ emissions by 90% compared with a diesel The BioGNVAL project has demonstrated that we can produce a clean fuel that does not emit any fine particles, makes 50% less noise and cuts CO₂ emissions by 90% compared with a diesel engine, all from our wastewater. The BioGNVAL industrial demonstrator can treat almost 120 Nm³/h of biogas, to produce one ton/day of bioLNG, or the equivalent of two full tanks for a heavy  vehicle. Tests have shown that the wastewater produced by 100,000 inhabitants could produce enough bioLNG to fuel 20 buses or 20 trucks.