Assessment of a wastewater stabilization pond system for removal of arsenic, iron, and ammonia from reverse osmosis water treatment plant residual wastewater

Drinking water treatment plants (DWTPs) produce wastewaters with elevated concentrations of heavy metals, metalloids, ammonia, and other contaminants. These require via processes including wastewater stabilization ponds (WSPs). This study assessed the arsenic (As), iron (Fe), ammonia (NH3) in a Saskatchewan DWTP WSP system five sequential ponds. Drone imaging combined flow depth data was used to estimate retention times which increased from 7-9 8-10 days after upgrade. Concentration trends showed Fe decreased Pond 1 3 Ponds 5, while As 5. Average effluent 10.6 µg/L were over 5.0 guideline, both NH3 guidelines easily met post-upgrade 2020. Several actions are recommended ensure adequate operation dredging, aeration, installing macrophytes capable uptake.