After the water has been filtered, water treatment plants may add one or more chemical disinfectants (such as chlorine, chloramine, or chlorine dioxide) to kill any remaining parasites, bacteria, or viruses. Once water has been treated with the coagulation chemicals it enters a tank with giant paddles.

These mix the chemicals and water together and enable the micro particles to form into larger pieces that are likely to stick together, making the sedimentation process in water treatment more effective.