Evaluation of ammonia recovery from swine wastewater via a innovative spraying technology

An innovative spraying system for NH₄ ⁺-N removal and recovery was investigated under different pH, temperature, spraying frequency and rate by using spraying system. Results showed that NH₄ ⁺-N removal efficiency and mass transfer coefficient (K_La) value in swine wastewater (SW) remarkably increased with increasing of temperature, spraying frequency and rate due to promoting the diffusion of NH₃ molecules caused by increasing specific surface of SW molecule, and high shear force and temperature difference between SW and circulating heating tube. Considering the cost and discharge standard, the optimum parameters for NH₄ ⁺-N removal from SW using spraying system were alkaline, 0.24 m³ h⁻¹ of continuous spraying, and 45 °C circulating water, and the NH₄ ⁺-N decreased from 591.2 to 68.9 mg L⁻¹ (<80 mg L⁻¹) after 8 h treatment, and this value corresponded to 88.35% removal rate. Furthermore, over 85% recovery rate for NH₄ ⁺-N could be obtained through absorption of phosphoric acid.