Water and Wastewater Terms Beginning F

A B C D E F G H I J K L M N O P Q R S T U V W Y Z

free available chlorine residual

The amount of chlorine available at the end of a specified contact period in chlorinated water or wastewater. This residual may be in the form of dissolved gas (Cl₂), hypochlorous acid (HOCl), or hypochlorite ion (OCl^–), but does not include chlorine combined with an amine (ammonia or nitrogen) or other organic compound.