O₂ Injection & H₂S Removal

Micro-aeration is the controlled injection of small amounts of oxygen into the biogas headspace under a digester cover. This promotes the growth of naturally occurring sulfur-oxidizing bacteria that convert hydrogen sulfide (H2S) into harmless elemental sulfur. The process is biological, continuous, and requires no chemical inputs or media replacement. EFI's proprietary O2 injection systems use this micro-aeration technology to eliminate H2S from biogas at a fraction of the cost of traditional chemical scrubbers.

EFI's O2 injection systems consistently reduce hydrogen sulfide from 3,000+ ppm to under 100 ppm, with many installations achieving levels below 50 ppm. The systems are designed to treat biogas with H2S concentrations ranging from a few hundred ppm to over 8,000 ppm. System sizing is based on biogas flow rate and incoming H2S concentration to ensure adequate treatment capacity for your specific operation.

O2 injection offers dramatically lower operating costs compared to chemical scrubbers. Traditional iron sponge or activated carbon scrubbers cost $5,000 to $35,000+ per month in media replacement alone, plus labor for changeouts and hazardous waste disposal. EFI's O2 injection systems cost only $200-500 per month in electricity with no media replacement ever needed. The biological process provides consistent H2S removal without the performance degradation that occurs as scrubber media depletes. Most installations achieve full payback within 6-12 months.

Yes, O2 injection is safe when properly designed and controlled. EFI's systems inject air at oxygen concentrations well below the lower explosive limit (LEL) for methane-oxygen mixtures. Built-in safety controls continuously monitor oxygen levels and automatically shut down the system if concentrations approach safety thresholds. EFI has safely operated these systems across hundreds of installations without incident.

O2 injection systems require minimal maintenance. Routine tasks include a quarterly blower check to verify proper air delivery, annual calibration of oxygen monitoring sensors, and periodic inspection of the injection manifold and piping. There is no media to replace, no chemicals to handle, and no hazardous waste generated. EFI offers O&M contracts that include all scheduled maintenance and 24/7 remote monitoring for complete operational oversight.