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Exploit the energy of water and waste

SUEZ is actively combating climate change by developing innovative solutions to reduce its customers’ greenhouse gas emissions, to optimize their energy consumption and to encourage the use of high-potential renewables.


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Use the energy in wastewater treatment networks to produce ecological heat

Rising energy prices and the application of carbon taxes demand efficient measures in the ways we collect energy. With its Degrés Bleus solution, SUEZ has developed an economical and ecological solution that captures the heat in wastewater and re-injects it into heating circuits.

Swimming pool at Levallois-Perret
By producing green energy, Degrés Bleus reduces greenhouse gas emissions by 50 to 70% compared with a conventional thermal solution.

From 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, which does not cause any nuisances and is completely safe, can be adapted to both new and existing networks in housing units, offices, hospital,retirement homes, schools, etc.

300-tonne reduction in CO2 emissions per year

By producing green energy, Degrés Bleus cuts greenhouse gas emissions by 50% to 70% compared with traditional thermal solutions. It also helps to conserve natural resources by reducing the consumption of non-renewable energy by 30% to 60%.

13 sites in France already

After the first site to employ the solution in 2010, the Aquatics Centre in Levallois-Perret “Degrés Bleus” is now also in use 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).

Recovering the biogas from a water treatment station to supply cities with energy

The biogas from the sludge in the wastewater treatment plant is purified to produce biomethane, which has all the properties of natural gas. SUEZ calls on its expertise in the sustainable management of waste to develop new solutions that use biomethane for its customers. Its target is to increase its output of biogas by 30% to 50% by 2020.
SUEZ wastewater treatment plant in Strasbourg
“It is the best possible energy equation: green and 100% local production from an inexhaustible source, transported without any trucks or losses in our networks, all as part of a short circuit.”

Olivier Bitz President of Réseau GDS

In Strasbourg, France, where SUEZ operates the wastewater treatment station, the Group has 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 natural gas network. BIOVALSAN was supported by the European Commission’s LIFE+ program for the example it has set in regional energy transition.

7,000 tonnes of CO2 emissions avoided

BIOVALSAN has cut by two-thirds the CO2 emissions from the La Wantzenau water treatment station, the fourth-largest in France, with a treatment capacity of one million population-equivalent. 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 of all the facilities in France. This new source of renewable energy has launched the transition towards a new local, sustainable and carbon-sober energy model in Strasbourg.

Transforming biogas into green fuel

In 2014, the regulations were changed to authorize the injection of biomethane from water treatment stations into the natural gas distribution network. Even if this network is well developed in France, it does not cover the whole country. With its BioGNVAL solution, SUEZ proposes an alternative to the injection of biomethane into the natural gas distribution network.
SUEZ wastewater treatment plant
“In my opinion, this biogas from our purification stations represents a concrete contribution by the regions to the common effort to make the energy transition”

Belaïde BedreddinePresident of the SIAAP

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.

Significant reduction of 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 engine, from our wastewater. The BioGNVAL industrial demonstrator can treat almost 120 Nm3/h of biogas, to produce one tonne/day of bioLNG, or the equivalent of two full tanks for a heavy good vehicle. Tests have shown that the wastewater produced by 100,000 inhabitants could produce enough bioLNG to fuel 20 buses or 20 trucks.

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