_City Bacteriologist and Chemist, Ottawa; Capt. Canadian Army Hydrological Corps; Associate Member of Committee on Water Supplies, American Public Health Association; Member of Committee on Water Standards and Standard Methods of Analysis, American Water Works Association; Chairman of Committee on Standard Methods of Analysis, Canadian Public Health Association_ _FIRST EDITION_ NEW YORK JOHN WILEY & SONS, INC. LONDON: CHAPMAN & HALL, LIMITED 1918 Copyright, 1918 BY JOSEPH RACE, F.I.C. PRESS OF BRAUNWORTH & CO. BOOK MANUFACTURERS BROOKLYN, N. Y. DEDICATED TO ~Sir Alexander Houston, K.B.E., D.Sc., M.B., C.M.~ PREFACE No apology is necessary for the publication of a book on the chlorination of water. This method of treatment, practically unknown fifteen years ago, has advanced in popularity during the last decade in a most remarkable manner, and in 1918 over forty millions of people are being supplied with chlorinated water. It may justifiably be said that no other sanitary measure has accomplished so much at so small a cost; and that civilization owes a deep debt of gratitude to the pioneers in municipal water chlorination: Dr. A. C. Houston in England, and Mr. G. A. Johnson and Dr. Leal in America. In this volume I have endeavoured to collect and correlate the information hitherto scattered in various journals and treatises and to present it in a comprehensible manner. The various aspects and methods of chlorination are discussed and suggestions have been made which, I hope, will stimulate research work in this fertile field of science. I wish to acknowledge my indebtedness to the engineering staff of the Ottawa Water Works Department and to Lieut. W. M. Bryce for the preparation of diagrams. JOSEPH RACE. OTTAWA, ONT., April, 1918. CONTENTS CHAPTER PAGE I. HISTORICAL 1 Sodium Chloride. Chlorine. Bleach. Eau de Javelle. Antiseptics. Hermite fluid. Webster's process. Electrozone. Chlorination of sewage in Germany, U. S. A., and England. Chlorination of water. Lincoln installation. Oxychloride. German experiments. European practice. Inception of chlorination in America. II. MODUS OPERANDI 14 Composition of bleach. Bleaching action. Nascent oxygen hypothesis. Hydrolysis of bleach. Effect of acids and salts on hydrolysis and germicidal action. Effect of ammonia. Direct toxic action. Hypochlorous acid. Sodium hypochlorite. Chlorine water. Nature of action. III. DOSAGE 30 Organic matter. Initial count. Viability of organisms. Mineral matter. Colour. Temperature. Admixture. Contact period. Turbidity. Light. Determination of dosage. IV. BACTERIA SURVIVING CHLORINATION 50