The Sterilizing Effects of the Formation of Hypochlorous Acid on Water

The purpose of this experiment was to determine which of the forms of hydrochlorous acid (HOCl), liquid or electrolyzed from a salt solution, would produce the most sterilize water while maintaining a stable pH level.  Three tanks were created for this process: a tank where liquid HOCl was used, a tank where the HOCl was produced from the electrolysis of salt water, and a control tank with no chemical treatment to ensure that the chemicals were working.  The pH levels of each tank were recorded every day, and culture dishes were used to grow bacteria from the water every four days.  Observations were recorded and then compared using a descriptive analysis.  It was concluded that the liquid HOCl tank yielded the smallest amount of bacteria while maintaining the most stable pH.  The salt and electrolysis also had an effect on bacteria levels, as the bacteria levels from this tank were lower than the control.  The liquid chlorine method of sanitizing a pool was more effective than the salt and electrolysis method.  This experiment could be used to help home pool users determine the best way to sterilize a pool.

Research Done By:

Emily Belarski
Cousino High School

Ryan Rivard
Sterling Heights High School