Anaerobic treatment of industrial effluents (traduction du titre et sous-titre en anglais)

Anaerobic digestion, or methanization, is a natural biological process which, when carried out within controlled processes, enables organic pollution to be effectively treated and biogas to be produced. The main component of this biogas, methane, can be used to generate electricity, heat or CNG, or injected into the natural gas network. Initially applied to the recovery of livestock by-products, methanization is now widely used for the purification and recovery of industrial effluents loaded with organic matter.

Methanization transforms organic matter, in soluble or solid form, leading to the formation of biogas, a gaseous mixture composed mainly of methane (CH ₄ ) and carbon dioxide (CO ₂ ). It is carried out in the absence of oxygen by a diverse microbial community in a variety of natural ecosystems: marine and freshwater sediments, animal digestive tracts, landfills, soils, etc. In particular, it is the source of spontaneous phenomena such as will-o'-the-wisp and marsh gas emissions.

Biogas from anaerobic digestion is a flammable mixture that may contain, in addition to CH ₄ (50-70% by volume) and CO ₂ (25-45% by volume), variable amounts of water vapor, H ₂ S and traces of H ₂ and other minority compounds.

When valorized, biogas is a source of renewable energy insofar as it is derived from organic matter of plant or animal origin, with short renewal cycles. Used for the benefit of mankind, methanization is an effective tool for reducing organic pollution and producing energy.

Its first application, which is still the most important in terms of number of units, was on-farm energy recovery from livestock and agricultural by-products. Countries such as Germany and China have a large number of delocalized sources of energy in the form of agricultural biogas.

Since the early 1970s, numerous research and development projects in the field of methanization have contributed to the increasingly effective application of the process to the purification and recovery of industrial effluents loaded with organic matter. The success of anaerobic digestion in the treatment of industrial wastewater is due in particular to the fact that, unlike conventional aerobic purification processes, which require a high level of electricity for aeration, it produces net energy. Another advantage of anaerobic digestion is that it produces less sludge than aerobic plants. Last but not least, anaerobic effluent treatment is generally carried out at a...