When water treatment is mentioned, the first thing comes to your mind should be chlorine. Chlorine has been widely used for tap water disinfection and purification for decades. But today, chlorine’s dominance in water treatment field is under challenge. The challenge comes from ozone. Ozone water treatment with ozone water generators has become more and more popular for home, business, and industrial use. In this blog, we will compare the use of chlorine and ozone in water treatment from several aspects. Chlorine Chlorine is a nonmetallic element. Chlorine gas at room temperature and pressure is a yellow-green gas with a strong pungent smell. It is chemically active and toxic. The earliest use of chlorine to disinfect water appeared in Britain