Nuoro realizes innovative biomethane and riothermy project at Aquafin Gent

08/10/2024

Nuoro realizes innovative biomethane and riothermy project at Aquafin Gent

Nuoro has won the tender for an innovative project at the Aquafin treatment plant in Ghent, where the biogas process is being completely revamped and new methods for energy recovery are being introduced. This project is part of a broader Aquafin initiative across different sites. The wastewater treatment company is focusing on biomethane and riothermy to further green its energy management. Nuoro is responsible for the works at the Gent WWTP, where the company is overseeing the integration of biogas upgrading and the complete realization of the riothermy solution.

From CHP to biomethane: a sustainable leap forward

The Gent WWTP treats wastewater from 230,000 people, making it the second-largest plant in Flanders. The sludge produced in the treatment process is digested, generating biogas. Previously, this biogas was burned in CHP (combined heat and power) plants, producing both electricity and heat. While this process has worked well for many years, two significant issues have arisen:

 

  1. Less profitable: The green electricity certificate system was phased out, making CHP plants financially less attractive.
  2. Environmental impact: CHPs emit nitrogen and combustion gases, which are harmful to the environment.

 

In response to these challenges, Aquafin decided to replace the CHP installations with biomethane plants. In this process, biogas is purified into biomethane, which is chemically equivalent to natural gas and can be injected directly into the natural gas grid. This gives Aquafin the opportunity to sell the gas internationally, with countries like Germany offering premium prices for green gas.

Heat extraction from treated wastewater: riothermy

A unique innovation in this project is the use of riothermy. A heat pump extracts heat from treated wastewater, also known as effluent. Previously, the heat from CHP plants was used to warm the digesters, but with the switch to biomethane, a new heat source is needed.

 

The solution lies in the effluent from the treatment plant. Through a heat exchanger and heat pump, the heat from the treated water is reused to maintain the digesters at the right temperature. This process is being applied on this scale for the first time in Belgium and represents an important step in making energy supplies more sustainable by using wastewater streams.

Innovative partnerships

Nuoro is working closely with Prodeval, the French market leader in biogas upgrading, on this project. Thanks to this partnership, Nuoro was able to bring advanced biomethane production technology to Belgium.

"This water and energy project is a big step for Nuoro. We aim to implement sustainable technologies in the water sector on a large scale."

Timeline and prospects

The works started in the summer of 2024, and the full installation is expected to be operational by the spring of 2025. At that time, biomethane will be injected as green gas into the Fluvius natural gas grid. The riothermy project in Gent has a heat capacity of 700 kW.

 

Ben Snoeks, project manager at Aquafin, adds: “This project shows how we can turn both biogas and treated wastewater into valuable energy sources using innovative technologies.”

Want to learn more about this project or how Nuoro can help your organization with sustainable energy solutions?

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