REDUCTION OF FREE AND COMBINED CHLORINE WITH GRANULAR ACTIVATED CARBON.

Chlorine residual is sometimes in excess of desired levels, and consequently it has to be removed or reduced in concentration. This may be the case, for example, after breakpoint chlorination, or disinfection especially when the contact period between the chlorine residual and the organic compounds present in water and wastewater is to be minimized. Dechlorination has also been of interest to industry where it may be required before demineralizers, for boiler makeup water, certain food plant operations or in beverage processing. A discussion is presented of two of the most common processes for removing chlorine residuals: the use of sulfur compounds and activated carbon.