Powdered marble wastes reuse as a low-cost material for phosphorus removal from aqueous solutions under dynamic conditions

In this study, phosphorus anions removal efficiency from synthetic aqueous solutions and urban secondary treated wastewater solutions by powdered marble wastes (PMW) as an effective low-cost material has been investigated using continuous stirring reactors (CSTRs). The experimental results showed that the phosphorus removal from the synthetic solutions is dependent on the PMW dosage and especially on the influent feeding flow rate. Indeed, for an influent aqueous concentration of 100 mg L^-1 and a PMW dose of 12 g L^-1, the average phosphorus removal efficiency increases from about 35 to 79% when the feeding flow rate was decreased from 10 to 2.5 mL min^-1. For a relatively high phosphorus influent concentration (100 mg L^-1), the highest removal efficiency, more than 88%, was observed for two CSTRs disposed in serial mode, a feeding flow rate of 4.5 mL min^-1 and a PMW dose of 12 g L^-1. The cost-effective and high phosphorus removal capability of PMW, compared to many natural or industrial byproducts, make them very promising materials for phosphorus removal and recovery from secondary treated wastewaters with the possibility of reuse as a fertilizer in agriculture.