Phosphorus removal and recovery from livestock wastewater by using modified zirconium‑lanthanum magnetite

Phosphorus removal and recovery from livestock wastewater (swine and cattle wastewater) could practically alleviate the phosphorus resource predicament. Til now, phosphorus recovery and reusability from livestock wastewater especially cattle wastewater via adsorption was limited investigated, while the Zr-La@Fe₃O₄ magnetite was previously demonstrated for cost-effective P adsorption in simulated wastewater. In this study, the influence of adsorbent dosage, pH, hydrodynamic and COD on phosphorus removal and recovery from raw real livestock wastewater were investigated. Moreover, kinetics mechanism and reusability implementation for phosphorus removal were examined. The results showed that phosphorus removal efficiency reached 99.9 % under adsorbent dosages (0.5–1 g/L). Higher removal efficiency achieved at pH 7 and 8 for all phosphorus species compared to acidic or alkaline pH conditions for swine and cattle wastewater, respectively. Besides, hydrodynamical test indicated that phosphorus removal efficiency was higher at increased stirring speed, and intraparticle diffusion model fitted well (e.g., R² = 0.941 and 0.974) for TP (Total Phosphorus) from the cattle and swine wastewater, respectively). The higher adsorption capacity for IP (Inorganic Phosphorus, 287 mg/g), and TP (295.6 mg/g) was observed for swine wastewater than cattle wastewater. The removal efficiencies of IP, TP, and OP (Organic Phosphorus) were enhanced when COD concentration decreased with increased reaction time. The maximum desorption efficiencies for cattle wastewater were 78.9 % (IP), 79.9 % (TP), and 85.2 % (OP), while for swine wastewater, range varied from 70.9 % to 91.5 % (IP), 75.3 % to 93.7 % (TP) and 89.8 % to 98.3 % (OP). Overall, the Zr-La@Fe₃O₄ adsorbent is effective in practical applications.