A/O Process with Alum Feed The Clark County Water Reclamation Facility (WRF) is in Las Vegas, Nevada. Three major factors contribute to reliable phosphorus removal and nitrification at this facility: (1) multiple chemical feeding, (2) good biological phosphorus removal with in-plant volatile fatty acid (VFA) generation and full nitrification, and (3) good tertiary filters for suspended solids removal this combination of chemical, biological, and physical processes in series is effective in providing exceptionally low phosphorus (0.09 mg/L) and ammoina-nitrogen (0.05 mg/L) concentration.