Disinfection of sewage is of primary concern to shellfish sanitation. The use of chlorine and its compounds is practically the only means used for sewage disinfection and therefore many in shellfish sanitation should be familiar with chlorination practices. The authors have attempted to combine the important aspects of sewage chlorination as found in the published literature in order to eliminate the necessity of searching out the references by the reader. The subject material is applicable to design, construction, and modification of the important factors of chlorination in considerably more detail than generally found in a sewage treatment plant design manual.