H2O2

Hydrogen peroxide is a strong oxidizer.
In fact, it is more potent than chlorine (Cl2), chlorine dioxide (ClO2), and potassium permanganate (KMnO4).
Also, through catalysis, hydrogen peroxide can be converted into hydroxyl radicals (OH).
This blog is not to say that one technology is better than the other, but rather to make you aware of what chlorine can and cannot do and understand what role the use of hydrogen peroxide can play in water treatment.