Which contaminant is primarily targeted by chemical precipitation in wastewater treatment?

Chemical precipitation in wastewater treatment is primarily used to remove phosphorus from the wastewater stream. This process involves adding chemicals, such as aluminum or iron salts, to react with soluble phosphorus and convert it into insoluble forms that can be separated from the water. The filtration or settling of these insoluble compounds effectively reduces phosphorus levels in the effluent, which is crucial for preventing eutrophication in receiving water bodies.

Phosphorus is a key nutrient that can often lead to harmful algal blooms and degraded water quality when present in excess amounts. By targeting phosphorus through chemical precipitation, wastewater treatment facilities can significantly contribute to protecting aquatic ecosystems and ensuring compliance with regulatory discharge limits.

While nitrogen, heavy metals, and organic compounds are also significant contaminants in wastewater, they are typically removed through other treatment processes such as biological processes, adsorption, or advanced oxidation processes that do not primarily rely on chemical precipitation.