Biogas & digestion

Enviro-Chem METHA

Reducing H₂S at the source in biogas units

Enviro-Chem METHA is a low-dose liquid solution designed for anaerobic digesters. It helps reduce H₂S in biogas, limit the activity of sulfate-reducing bacteria and improve the biological stability of the process.

Unlike purely curative treatments, METHA combines action on already-present sulfides with a preventive approach targeting H₂S formation at the source.

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H₂S reduction

SRB preventive action

Biological stability

Simple liquid dosing

Enviro-Chem METHA container for H₂S control in biogas and anaerobic digestion

Preventive + curativeLow doseBiogas

Key technical points

1. Inhibition of sulfate-reducing bacteria

Copper acts upstream by disrupting the enzymatic activity of sulfate-reducing bacteria. These bacteria use sulfates to produce sulfides, which then convert into H₂S. By reducing their activity, METHA limits H₂S formation at the source.

2. Reduction of already-formed H₂S

Enviro-Chem METHA contains soluble copper capable of reacting with dissolved sulfides to form insoluble copper sulfide. This curative action neutralises part of the H₂S present in the medium and limits its passage into the biogas.

3. Better substrate availability for methanogens

Sulfate-reducing bacteria compete with methanogens for key substrates such as hydrogen and acetate. By limiting this competition, METHA can promote a more favourable environment for methane production.

4. Biological process stabilisation

The reduction of H₂S and the limitation of volatile fatty acid accumulation contribute to more stable digester operation. The product is designed to support a progressive approach, with monitoring of H₂S levels, pH and biological performance.

Target applications

Agricultural and industrial biogas units
Anaerobic digesters with high H₂S levels
Sites currently using iron hydroxide, ferric chloride or other curative treatments
Installations seeking to reduce chemical volumes and handling
Digesters requiring a more preventive approach to H₂S

Why a progressive action?

METHA acts immediately on part of the sulfides present, but its main effect relies on a gradual shift in the biological balance of the digester. The inhibition of sulfate-reducing bacteria, the adaptation of methanogens and process stabilisation all take time. First effects may appear after a few weeks, while optimal performance depends on hydraulic retention time, organic load, initial H₂S level and injection point.

Recommended start-up strategy

When a digester already has high H₂S levels, it may be advisable to temporarily maintain a curative iron-based treatment during the first weeks. Iron quickly neutralises already-formed H₂S, while the copper in METHA remains more available for its preventive role on sulfate-reducing bacteria. This approach facilitates a gradual transition towards lasting system stabilisation.

Operator benefits

H₂S reduction in biogas

Potential reduction in the need for curative treatments

Less storage and handling than with high-dose products

Improved biological stability of the digester

Technical support based on site data

Useful data for an initial assessment

To evaluate dosing and injection point, SARGO can analyse the following information:

volume or tonnage of inputs per day
type of inputs
digester volume and retention time
average and maximum H₂S levels
currently used treatment
available injection point (e.g.: premix, pre-mixing pit, addition at hopper...)

On-site implementation

Enviro-Chem METHA can be simply integrated into existing installations, via a dosing pump, controlled dilution or an injection point adapted to the premix, fresh inputs or available circuit.

Dilution and dosing system

Dilution and dosing installation for regular product injection.

Injection from IBC

Simple solution with IBC and dosing pump for trials or permanent installations.

Adapted injection point

Injection as close as possible to the mixing zone to improve contact with inputs and promote preventive action.

Request a METHA technical assessment

Send us your digester data and current situation. We will propose an initial guidance on dosing, injection point and start-up strategy.

Request a METHA technical assessment View product page