Enhanced Coagulation Requirement
According to USEPA Stage 1 (1999), a TOC concentration higher than 2 mg/l in the raw water is the trigger for the implementation of enhanced coagulation or softening. Waters with a TOC level less than 2 mg/l do not require enhanced coagulation or softening, since the NOM is formed mainly by fulvic acids which are less reactive with chlorine. Stage 1