Phosphate mine wastes reuse for phosphorus removal from aqueous solutions under dynamic conditions.

Phosphate mine slimes (PMS), an abundant waste generated from phosphate mines, was used in this study as a cost-effective adsorbent to investigate the phosphate anions removal from synthetic and urban secondary treated wastewater solutions. Dynamic experiments using laboratory reactors were carried out to study the effect of phosphate influent concentration, PMS dosage and feed flow rate on phosphate removal and a kinetic model was used to determine the phosphate mass transfer coefficients. The results show that the phosphate removal increases with influent phosphate concentration and PMS dosage. The feed flow rate has no significant effect. On the other hand, the phosphate removal from wastewater is less efficient than the synthetic solution due to anions competition process. The evaluation of phosphates mass transfer coefficients confirms the presence of anion competition phenomena and the necessity of increasing PMS dosage to provide more adsorption sites. The cost-effective and high adsorptive capability of PMS make them attractive materials for phosphate anions removal and recovery from secondary treated wastewaters with the possibility of agronomic reuse as fertilizer.