City of Bastia

The client’s objectives and expectations

• Identify a recovery solution for the sludge from the Bastia Sud wastewater treatment plant, as well as potentially from Marana Golo and Casinca. This approach also includes the management of part of the household biowaste produced in the Bastia urban area, focusing on the organic fraction.

• Inject biomethane into the city’s gas network, with the ultimate goal of gradually replacing fossil-based gas with a renewable and sustainable energy source.

Our main missions

Analyze the technical and economic feasibility of creating a methanization unit using sludge from the Bastia wastewater treatment plant and household biowaste produced in the urban area, while exploring the integration of other potential inputs.

Project characteristics:

• Identified inputs: 10,000 tons available within a maximum collection radius of 30 km.
• Project location: Site selected near the Bastia wastewater treatment plant (Arinella area).
• Footprint: Approximately 5,000 m², including the input storage shed, hygienizer, digesters, and ancillary facilities.
• Management of liquid digestate: recycled at the digester inlet or treated via a reed bed filter system before returning to the wastewater treatment plant.
• Valorization of solid digestate: transformed into compost for agricultural or horticultural use.

Results obtained

Forecasted biomethane production: Approximately 850,000 Nm³, corresponding to 8,000 MWh HHV.

Injection method: Direct injection into the city’s propane network, covering about 10% of the annual consumption of the network users.

Main barriers and obstacles:

Compost limitation: Compost not usable in agriculture due to the mixed origin of the organic waste used.

Regulations: Legal restrictions preventing the valorization of liquid digestate.

Land issue: The identified land is not owned by the city and is located in a flood zone.

Technical complexity: Challenges related to blending biomethane with the propane already present in the network.

This project gave me the opportunity to connect my studies in agronomy with my role as an engineer and consultant specializing in renewable energy projects. Exploring the specificities and constraints related to the overseas environment was a particularly enriching experience.

Marc M., Project Manager at Best Energies