This lecture covers the advanced topics in wastewater treatment, focusing on the biochemical oxygen demand, oxygen-demanding wastes, chemical precipitation of phosphate, biological phosphate removal, and the impact of oxygen-demanding wastes on rivers. It also discusses the post-denitrification process, biological nitrogen removal, and the newest developments in biological phosphate removal. The lecture concludes with a summary of the wastewater treatment process and the challenges posed by micropollutants in the aquatic environment.