One of twelve water treatment technology units, this student manual on chlorination provides instructional materials for nine competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: purpose and process of chlorination, chlorine residuals, free chlorine determination, raw water chlorine demand test, gas chlorinators construction, gas chlorinator use and safety precautions, first aid for chlorine gas victims, hypochlorite solution preparation, and using a hypochlorinator. For each competency, student objective, resources (information sheets, references to manuals, and appendix materials), learning activities, and evaluation activities are provided. The appendices contain information sheets on chlorination. Generally, an evaluation form with answer key is provided for each student competency. (JH)