vanzari@infinitrade-romania.ro
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Infinitrade Romania – industrial equipment supplier in Romania

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    Equipment for Biogas and Green Energy

    Biogas plants feed the digester with fibrous substrate and must be protected against hydrogen sulphide (H2S), which is corrosive to many metals, while the space under the cover is usually classified as an ATEX zone under Directive 2014/34/EU. We quote progressive cavity or lobe pumps for substrate, pH and level sensors, aeration blowers, submersible agitators and biocompatible valves. Send us the substrate type and the dry matter percentage.

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    Applications

    • Digester substrate feed
    • Digestate recirculation and mixing
    • Biogas desulphurisation
    • Cogeneration (biogas engine)
    • Digestate treatment and phase separation

    Equipment we supply for biogas and green energy

    • Biomass pumpsProgressive cavity and lobe pumps for viscous substrates containing fibres
    • pH and level sensorsFermentation process monitoring - pH, temperature, digester level
    • Aeration blowersSide channel blowers for lagoon aeration and post-treatment
    • Submersible agitatorsSubstrate mixing in the digester for uniform fermentation
    • Biocompatible valves and pipingResistant to H2S and to the corrosive media typical of biogas

    Brands often requested

    • Grundfos
    • Wilo
    • WIKA
    • Endress+Hauser
    • Becker

    Frequently asked questions

    Which pump withstands conveying substrate with fibres and straw from a biogas digester?

    Agricultural substrate (manure, silage, plant residues) contains long fibres and occasional foreign objects, which quickly block a standard centrifugal pump. Progressive cavity or lobe pumps tolerate these particles and keep a steady flow even at high viscosity, which makes them the standard choice for digester feed and recirculation. For very fibrous substrate we also recommend a chopping/shredding system upstream of the pump, which reduces the risk of blockage and excessive rotor wear. Send us the substrate type and the dry matter percentage for correct sizing.

    Which materials resist H2S in biogas installations?

    Hydrogen sulphide (H2S) produced by anaerobic fermentation is corrosive to many common metals, especially in combination with the moisture in biogas, which forms sulphurous acid. For directly exposed components (valves, sensors, piping around the digester or the desulphurisation stage) we recommend corrosion-resistant stainless steel or compatible plastics (PVC, PE, PP for piping), depending on the H2S concentration and process temperature. For high H2S concentrations it is useful to refer to the principles of ISO 15156 (resistance to sulphide-containing environments), which is normally used for material selection in 'sour' service in the gas industry.

    Which ATEX zone applies to a biogas digester and which equipment must be certified?

    The space under the digester cover, where biogas (mainly methane) accumulates, is usually classified as an explosion-risk area, with zone 1 or 2 depending on how often gas can reach it under normal or abnormal operating conditions - the exact classification is set in the plant designer's zoning study. All electrical equipment installed in these zones (level sensors, submersible agitators, lighting) must be certified under Directive 2014/34/EU, with marking appropriate to the zone and the gas group. Check the classification in the project before ordering the equipment.

    Which sensors are essential for monitoring the anaerobic fermentation process?

    pH is the main indicator of process stability - a sudden drop can signal a build-up of volatile fatty acids and a risk of digester acidification, which practically stops biogas production if not corrected in time. Alongside pH, temperature sensors (mesophilic or thermophilic fermentation requires strict control, with variations of no more than 1-2°C) and digester level sensors complete the minimum monitoring package. For more advanced plants, biogas composition analysers (methane, CO2, H2S) help optimise feeding and protect the cogeneration engine.

    Which agitator should I choose for mixing the substrate in a digester?

    Submersible agitators are sized on the digester volume, the viscosity of the substrate and the possible formation of a floating layer (crust) at the surface, which needs extra mixing power to be broken up periodically. The propeller and housing material must withstand the corrosive H2S environment, and the submersible motor must be ATEX certified if the agitator operates in the biogas space of the digester. Insufficient mixing leads to sedimentation, crust formation and reduced biogas production - send us the digester dimensions and the substrate type for a recommendation of the power required.

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    Updated: 2026-11-12