Ammonia Removal from Swine Wastewater by Microwave-Assisted Stripping

Abstract

This study detetmined optimal microwave irradiation (MI) conditions for removal of ammonia nitrogen (NH3-N) from swine wastewater. The wastewater was treated using a laboratory-scale industrial microwave unit (2,450-MHz frequency). The removal of NH3-N increased with the increase of pH (9.5–12.5), final temperature (FT) (50°C≤FT≤100°C), and MI time (MIT) (0≤MIT≤140 min). Compared with conventional heating (CH), MI removed more NH3-N. The calculated NH3-N half-lives decreased as FT and pH increased. FT (80°C–100°C) and MIT (2.5–5.5 min) significantly affected the NH3-N removal. Within the design boundaries, optimal conditions for NH3-N removal (94.9%) were FT=100°C, MIT=5.5 min, and pH 10. This work shows the potential of MI as an effective method to reduce the NH3-N content in swine wastewater.