Fe-organic for H₂S removal is a chelated iron solution designed for hydrogen sulfide reduction directly inside anaerobic digesters. The product protects engines, upgrading systems, pipelines and reinforced concrete structures while reducing trace-element binding and minimizing sludge formation compared to FeCl₃ and iron hydroxide.

Why Remove H₂S Inside the Digester

Hydrogen sulfide causes:

• corrosion
• pipeline damage

In-situ desulfurization significantly reduces maintenance costs.

Trace Element Protection

Hydrogen sulfide binds essential micronutrients:

Co → CoS
Mn → MnS
Mo → MoS₂
Cu → CuS

This leads to:

• process instability
• reduced methane yield
• higher trace element consumption

Fe-organic prevents these reactions.

Operating Principle

H₂S + 2Fe³⁺-EDTA → S⁰ + 2Fe²⁺-EDTA + 2H⁺

2Fe²⁺-EDTA + ½O₂ + H₂O → 2Fe³⁺-EDTA + 2OH⁻

Advantages:

• catalytic reaction mechanism
• reduced iron consumption
• formation of elemental sulfur instead of FeS sludge

No Cross-Reactions with Phosphates or Carbonates

Unlike FeCl₃ and Fe(OH)₂:

• no phosphate or carbonate precipitation

Behavior of Fe(OH)₂ in the Digester

Fe(OH)₂ is effective only within a narrow range: pH 8.3 – 9.8
Advantages: useful as an emergency correction reagent
Limitations:
- narrow effective operating window
- cross-reactions with carbonates and phosphates

Use of FeCl₂ as an Alternative Reagent to FE-organic

FeCl₂ can be applied as a lower-cost alternative.
However:
- possible formation of HCl
- increased corrosion risk
Additionally:
- digestate agricultural application performance may be negatively affected.

Performance Equivalence

1 litre ZORG' Fe-organic replaces approx. 20 kg iron granulate (40% Fe)
≈ 8 kg elemental iron removal performance

EXAMPLE. For a 1MW electric power biogas plant with 100% maize silage just 1,5 liter Fe-organic daily is enough.

Recommended Dosage

Typical:

1–3 mol Fe per mol S
50–250 ppm Fe in digester

Typical Applications

Suitable for:

• agricultural biogas plants
• poultry manure digestion
• protein-rich substrates
• waste digestion

Organic Farming Restriction: Fe-EDTA is not recommended for certified "bio" and organic digestate application. Instead of EDTA another chelate is used.