Chlorination

Chlorination of wastewater is the application of chlorine to a wastewater to accomplish some definite purpose.  The purpose of chlorination may not always be disinfection and may, in fact, involve odor control or some other objective which will be noted.  Chlorine may be applied in two general ways, gaseous and liquid.  In general, the effective chemical form of chlorine that either destroys the microbe or acts against odor, etc., is the same.  Gaseous forms of chlorine are generally first dissolved in water prior to addition to the wastewater stream, while liquid forms of chlorine (called hypo-chlorites) are sold in the form of water soluble salts.  Because chlorine gas generally costs less than hypo-chlorites, it is normally used in treatment plants except in rare instances where only a relatively small amount of chlorine is needed or where the possible danger from gaseous chlorine overrides economic considerations.  The application of chlorine is usually controlled by special devices which are known as chlorinators or by similar names