- Contaminant: Arsenic
- Matrix: Arsenic Trioxide Waste Material
- Reagent(s): Proprietary
- Site location: Africa
The problem: Arsenic trioxide waste material (ATWM) contains up to 40% leachable arsenic, which must be stabilized. The client had developed a proprietary method to leach the arsenic from the ATWM then remove the arsenic from the leachate, but additional information was needed in order to develop a design and cost estimate for a full-scale treatment system.
How PRIMA helped: PRIMA performed laboratory testing to help its client improve upon the proprietary method of stabilizing arsenic in ATWM and develop design parameters. With guidance from our client, we evaluated various leaching agents, concentrations, and extraction times to optimize removal of arsenic from ATWM, then tested various additives and dosages in order to create a stable, arsenic-laden solid that could easily be removed from the leachate. The final process met the project goals of being able to reduce arsenic in leachate to below the regulatory requirement of 0.1 mg/L while generating a sludge that passed TCLP. Based on the results of this testing, PRIMA’s client was able to develop a treatment system design and cost-estimate.