The first step includes coagulation and sedimentation. When raw water enters the treatment plant, coagulants are added to make smaller particles adhere to one another, become heavy and settle to the bottom of a large basin. The second step is filtration. The water is filtered to remove the remaining fine particles. The last step is called disinfection.
Chorine is added to kill harmful bacteria and viruses.
To adjust other chemical and aesthetic properties of the water, the Aqueduct uses lime for pH control and prevention of pipe corrosion, fluoride at low levels to protect teeth, and carbon and potassium permanganate to remove odors that could be caused by algae growth in the raw water.