Chlorine as an algicide in a conventional water treatment plant

Abstract

A study was conducted in the Beirut, Lebanon, Water Treatment Plant to determine the dose of chlorine lethal to algae which were causing operational difficulties in the Plant. In laboratory experiments, it was found that a single dose of 1.8 mg/1 of chlorine was sufficient to kill all the algal taxa growing in the plant. If the chlorine dose was regenerated to the original concentration every 24 hours, then a dose of 1.2 mg/1 was sufficient. In field studies, continuous dosing of chlorine to maintain a residual chlorine level of 0.8 mg/1 was found lethal to the algal taxa. Prechlorination is therefore recommended as an effective method for the control of algal growth in conventional water treatment plants.