Hydrogen Sulfide (H₂S) Removal in Landfill Gas Systems

Asset Protection and Uptime Preservation

The reduction of hydrogen sulfide (H₂S) is essential for the effective utilization of landfill gas (LFG). If not removed, H₂S accelerates corrosion, degrades engines and turbines, poisons downstream catalysts, and causes unplanned downtime. In the following section, we will first discuss the operational challenges presented by H₂S in landfill gas systems, followed by an examination of the underlying chemistry involved in its removal. Lastly, we will address why iron-based media, when properly implemented, remain the industry standard for reliable landfill gas treatment.

Corrosive Gas in a Variable Stream

Landfill gas composition is inherently variable. Flow rates fluctuate due to weather conditions and waste age, and H₂S concentrations can increase unexpectedly. Therefore, removal solutions must tolerate variability, protect equipment, and minimize change-outs, all without introducing additional complexity or infrastructure requirements.

Why H₂S Must Be Removed

Hydrogen sulfide in landfill gas presents risks beyond an unpleasant odor. Under moist conditions, it forms sulfuric acid, which corrodes carbon steel, copper alloys, and protective coatings. In power generation applications, even low concentrations can reduce engine lifespan and void warranties. Effective upstream removal represents the most cost-effective method of protecting system assets.

How Iron-Based Media Achieves High Loadings

FerroSorp® media utilizes iron hydroxide chemistry, which not only captures H₂S but also facilitates its chemical conversion to elemental sulfur in the presence of a small amount of oxygen. This conversion is operationally significant because it regenerates reactive iron sites and restores adsorption capacity, thereby extending media life and increasing sulfur loading per unit mass.

The reactions are straightforward and well-understood:

Adsorption

2 Fe(OH)₃ + 3 H₂S → Fe₂S₃ + 6 H₂O

Regeneration / Conversion

Fe₂S₃ + 1½ O₂ + 3 H₂O → 2 Fe(OH)₃ + 3 S

The overall result is increased usable capacity, reduced media replacement frequency, and more consistent performance under actual landfill conditions.

What This Means at the Site Level

In landfill gas systems using bulk media vessels, higher sulfur loading results in longer operational periods and lower operating costs. This leads to fewer media replacements, decreased labor requirements, and more consistent protection for engines, flares, or upgrading equipment, which is particularly advantageous at remote or minimally staffed sites.

Why Simpler Scavengers Fall Short

Although liquid scavengers and low-capacity solid media may initially seem cost-effective, quantitative comparisons indicate they are often inadequate for managing the flow variability and moisture content characteristic of landfill gas. For example, liquid scavengers typically require replenishment every 1,000–2,000 pounds of sulfur removed, whereas iron-based media can achieve sulfur loadings of up to 70–80% by weight before replacement is necessary (Interra Global, 2023). Additionally, handling liquids and frequent change-outs for low-capacity solids can increase operational labor and safety risks. Inconsistent breakthrough performance associated with these materials can further undermine any initial cost advantage. In contrast, iron-based media that convert H₂S to sulfur provide higher sulfur uptake per change-out cycle, thereby reducing lifecycle costs and offering more robust performance.

Where This Leads

The challenge of H₂S removal from landfill gas is fundamentally a reliability issue, not solely a chemical one. FerroSorp® integrates proven iron hydroxide chemistry, engineered for high sulfur loading, with application expertise to ensure optimal media performance within landfill gas systems.

In summary, for operators aiming to achieve stable operations, prolonged equipment life, and reduced total cost of ownership, comprehensive solutions from Interra Global—including media, vessels, and technical support—facilitate a more predictable and effective approach to landfill gas treatment.