Bio CO2

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Bio-CO2 (or biogenic CO2) is a by-product in the production of biomethane.

What is bio-CO2?


This type of carbon dioxide is a natural component of biogas produced by the fermentation of biological sludge at the wastewater treatment plant, along with other gases extracted from it during the filtration and concentration process (H2S, sulphur compounds, volatile organic compounds (VOCs), etc.).

Unlike undesirable components with potentially harmful effects, CO2 is considered a recoverable resource. It is therefore collected and treated for reuse.

What are the applications of bio-CO2?

Bio-CO2 collected during the purification process of raw biogas has a variety of potential applications:

  • In agriculture, to accelerate photosynthesis in greenhouse crops
  • In industry, as process gas
  • For refrigeration
  • In the production of dry ice
  • As a fire extinguishing agent, etc.

One of the challenges of the Biovalsan project is the study of possible applications for recycled CO2.

A closer look at the short carbon cycle

The scientific consensus is that the 'short CO2 cycle' is carbon-neutral, meaning that it does not add to the greenhouse effect.

Whilst conventional resources (oil, natural gas) trapped carbon underground for thousands of years, biomethane is extracted from organic resources, which store the carbon for only a short time. During the 'short cycle' conversion process, CO2 in the atmosphere is absorbed by vegetation, acting as a 'carbon sink' through the photosynthesis process.

At the end of the vegetative cycle, the resulting 'biomass' undergoes several transformations whereby it releases its stored carbon, mainly in the form of methane and CO2 (decomposition, natural or controlled digestion, oxidation, combustion, etc.).

This short cycle, which is the natural cycle of carbon, does not cause any increase in carbon levels in the atmosphere.