Abstract: A process for treatment of hazardous liquid waste comprising trace amounts of hazardous elements in solution as oxyanions by oxyanion fixation within ettringite and related minerals. In accordance with the disclosed process, reagents for forming ettringites are mixed with the waste stream resulting in the formation of oxyanion-substituted ettringite and related materials. The resulting ettringite and related minerals are separated by filtration from the liquid. Thereafter, the liquid, having an elevated pH, is neutralized by carbon dioxide sparging resulting in precipitation of excess reagents in the liquid. Thereafter, the precipitates are filtered, producing a clean liquid.