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 chlorine

Chlorine (Cl₂) in a liquid or gaseous form that combines with water to form hypochlorous (HOCl) and hydrochloric (HCl) acids. In wastewater, free chlorine usually combines with an amine (ammonia or nitrogen) or other organic compounds to form combined chlorine compounds.