Which chemical is used to remove phosphorus from wastewater as a precipitate?

The use of ferric chloride for phosphorus removal in wastewater treatment is well-established due to its effectiveness in precipitating phosphate ions. When ferric chloride is added to wastewater, it reacts with phosphate to form insoluble ferric phosphate. This compound can then be easily removed from the wastewater during the sedimentation process, allowing the water to be treated further or discharged.

Ferric chloride not only helps in phosphorus removal but also plays a role in enhancing the overall treatment process by improving flocculation and aiding in the settling of suspended solids. The ability of ferric chloride to produce a stable precipitate makes it a preferred choice among chemicals used for phosphorus removal in various wastewater treatment facilities.

While other chemicals listed can have roles in wastewater treatment, they do not specifically target phosphorus removal in the same way as ferric chloride, making it the most effective choice for this particular application.