What method is used to remove phosphate from water?

The method of precipitation at high pH is effective for removing phosphate from water due to the chemical reaction that occurs when phosphate ions interact with certain metal ions, such as calcium, aluminum, or iron. When the pH of the water is raised, phosphate can precipitate out of the solution as insoluble salts, such as calcium phosphate or aluminum phosphate. This process effectively reduces the concentration of phosphate in the water, making it suitable for various water treatment applications aimed at preventing issues like algal blooms.

By adjusting the pH to promote precipitation, treatment facilities can efficiently manage nutrient levels in the water, thus combating eutrophication and improving water quality. This method is commonly employed in both municipal and industrial wastewater treatment systems for its effectiveness and relatively low cost.