The economic and environmental benefits of anaerobic digestion: our experts’ views
Wastewater treatment plants represent a non-negligible cost for companies. With an innovative industrial methanization process, Dametis and its partners have turned this difficulty into an opportunity. The project currently underway with an agri-food company will generate profits while reducing environmental impact.
“Based on the data collected, we suggested installing a methanization module,” explains Sébastien Papouin, Technical Director of Energy and co-founder of Dametis. The start-up has been working with a major industrial group since spring 2022. It is supported by its network of experts, including EGIS, an international consulting and engineering group specializing in the environment; SET Environnement, a design office; and Mathias Welschbillig, a technical expert on the environment and wastewater in particular.
In addition to the anaerobic digestion module, the future site includes a new wastewater treatment plant (WWTP). “The company realized that too much effluent was being discharged from their current treatment plant. However, considering the presence of organic matter, it seemed sensible to install a methanization module alongside the WWTP,” explains Sébastien Papouin. “It’s an innovation for the next forty years,” stresses Yann Balem, energy project manager and design office engineer at Dametis.
Biogas, a green energy
Methanization is a biological phenomenon based on “the degradation of organic matter by micro-organisms” [1] , explain the experts at the French Ecological Transition Agency. This fermentation produces
Indirectly, this reduces the use of the wastewater treatment plant. Its operating costs, in terms of energy and payroll, are lower. What’s more, the fermentation process halves the amount of sludge. So there’s less waste. The water discharged is of higher quality, and the treated water can be reused. “We can halve a plant’s water consumption,” adds project manager Yann Balem. Finally, the sludge produced by methanization can be sold to farmers as fertilizer. “In this way, waste is not only reduced, but becomes a product. It’s a virtuous circle,” continues the engineer.
The interest is also environmental. As the French Ministry of Ecology points out, “the
biogas contributes fully to the objectives of the energy transition for green growth, namely the development of renewable energies, the reduction of greenhouse gas emissions and the development of a circular economy with the valorization of digestates from methanization in agriculture.” [2] So the optimization is as much economic as environmental. “This biogas, produced in-house, emits ten times less CO2 than imported natural gas. 1 kW of biogas consumed locally is 1 kW of natural gas not used.
It also increases the resilience of a region and a company,” explains Yann Balem.
How does methanization work?
The anaerobic digestion circuit includes an additional tank, smaller than the buffer tank. After these basins, the effluent is conveyed to a physico-chemical aeroflotter. The addition of reagents separates the wastewater, which goes to the WWTP, from the sludge, which goes to the digester. Material losses and waste are also integrated into this reactor, where fermentation takes place. During digestion, micro-organisms break down organic and biodegradable matter, thanks in particular to the absence of oxygen in this module. The biogas is then recovered. The digested sludge is concentrated, stored and then recycled for agricultural use. As for the dirty water sent to the WWTP, it is recovered by the clarifier from which clean water emerges.
A single point of contact for your methanization projects
“We’re currently in the preliminary design phase. This concerns the regulatory aspect,
explains Yann Balem. “The dossier is more complex because the procedure for installations classées protection de l’environnement (ICPE), which must be submitted to the prefecture, also concerns the methanization project. Dametis assists the customer in drawing up the environmental authorization application (DDAE). “To do this, Dametis has enlisted the help of experts. These include the engineering firms SET Environnement and GES.
Two distinct phases will then be carried out. One concerns the new WWTP, with water transfer, buffer basin, physico-chemical, biological and tertiary treatment. The other focuses on the methanizer and hygienization. “There is no subcontractor who can handle both the methanization and the WWTP,” explains Yann. “Dametis is therefore the equivalent of the conductor of the orchestra. From the call for tenders to project monitoring and analysis, we are our customer’s sole point of contact.”
The start-up thus plays a crucial role in advising, designing and implementing this major project. This service is all the more important given the current rise in energy costs
[3] and the rising price of water from 2023 [4].
Dametis supports you in your environmental transition
To find out more about how anaerobic digestion works and how to integrate green energy projects, contact Dametis, and our experts will guide you through the process.
Sources :
[1] https://www.insee.fr/fr/statistiques/6794043#titre-bloc-7
