The environmentally toxic nature of phosphoric acid plant wastewater is the focus of a new treatment scheme devised at Ben-Gurion University of the Negev, Israel. The acidic, saline properties of these effluents are effectively countered with a three-step process involving selective electrodialysis, reverse osmosis and neutralization.

When tested with synthetic wastewater under laboratory conditions, the treatment scheme was demonstrated to recover clean water and phosphate. Wastewater volume was reduced by 90% and sufficient sulfate was removed to prevent the mineral scaling, which can undermine membrane performance. Acidity levels in the reverse osmosis concentrate were neutralized by use of phosphate rock.

A three-step process for the treatment of phosphoric acid wastewater applies selective electrodialysis, reverse osmosis and neutralization. Source: ACS Sustainable Chemistry & Engineering (2022). DOI: 10.1021/acssuschemeng.2c03132

The power requirement for the process was documented to be as low as 4.4 kWh/m³ of wastewater. The research described in ACS Sustainable Chemistry and Engineering suggests this process would be a sustainable and techno-economically viable solution for the treatment of hazardous wastewater byproducts of the phosphoric acid industry.