How Green Steel PSR™ Works to Control Phosphorus and H₂S
Green Steel PSR™ is an upcycled byproduct from steel manufacturing that’s engineered to sustainably reduce phosphorus levels and remove sulfur in digesters – before it converts to H₂S. Unlike chemical treatment, it sequesters phosphates and sulfides while protecting alkalinity and digester stability. It also mitigates corrosion and scaling caused by metal salts, which further drives down operational costs. In addition to improving workplace safety, Green Steel PSR™ releases phosphorus in a slow, plant-available manner in the digestate — a characteristic that growers and fertilizer producers prefer.
Where Green Steel PSR™ is Dosed: Upstream of Anaerobic Digesters
Green Steel PSR™ is introduced into the treatment stream as a powder or slurry most anywhere upstream of digesters, including primary clarifiers and mixing tanks. Once loaded in digesters, results can start to be seen within hours. Phosphates and sulfides are adsorbed onto the surface of the material and settled into the biosolids, from which they can be slowly released in land applications.
Using Green Steel PSR™ to Remove Phosphorus from Wastewater
Green Steel PSR™ contains iron, calcium, and magnesium oxides that successfully sequester phosphates. It captures phosphorus through sorption to form stable, insoluble phosphates. This dual mechanism removes most of the soluble phosphate in digesters, but without the corrosion and scaling caused by metal salts.
How Green Steel PSR™ Removes Sulfur Before it Converts to H2S
Green Steel PSR™ also captures sulfides through sorption to form stable insoluble sulfates. At a steady-state dose, pilot studies showed up to 80% reduction in H₂S levels in digester biogas – substantially improving value and safety for energy recovery. Green Steel PSR™ reduces the scrubbing of H₂S to a polishing level. This also diminishes wear and corrosion of scrubbing infrastructure, in addition to fewer scrubbing media changeouts.
Green Steel PSR™ Provides Proven Performance Without Compromise
In long-term pilot testing, Green Steel PSR™. . .
Did not disrupt pH,
gas production, or microbial activity at recommended dosing levels
Improved biogas quality
with methane content remaining >60%
Contributed alkalinity
to support stable digestion conditions
A Low-Risk, Sustainable Alternative to Ferric and Alum
Unlike ferric chloride, ferric sulfate, or aluminum sulfate, Green Steel PSR™ is . . .
Upcycled from an industrial by-product, turning waste into value and helping create circular economies in wastewater treatment
Non-hazardous and non-corrosive with low leaching potential
Cost-effective, especially for facilities seeking to cut chemical costs and environmental impact
By replacing or reducing the need for common treatment chemicals, Green Steel PSR™
supports both regulatory compliance and sustainability goals.
Key Benefits of Green Steel PSR™ for Wastewater Treatment Operators
Removes phosphorus and sulfur simultaneously
Enhances biosolids quality for land application
Improves infrastructure longevity
Compatible with existing digestion systems
Enhances biogas purity