This article is based on data accumulated by AWWA Task Group 2680 P‐Manganese Deposition in Pipelines. Manganese is a common ingredient of impounded water and of many well waters. In public supplies, it causes such difficulties as staining of clothes and plumbing fixtures, “black” water, incrustation of mains, and interferences with the colorimetric chlorine residual test. In industrial supplies, it causes severe economic losses through discoloration of products, specks in finished goods, and reduction of pipeline carrying capacities. Chemical reactions are generally presumed to account for the greater part of the manganese in groundwater; in stored water, manganese builds up by a combination of biologic and chemical processes working simultaneously. It is difficult to obtain clear‐cut statements about the economic significance of manganese in water supplies. In spite of this, requests increase yearly for information on how to remove manganese, how much the process will cost, and what method will best suit a specific water supply. This article discusses the reporting of manganese, manganese‐reporting organisms, manganese determination, filter media, manganese stabilization, and manganese removal by the zeolite process or by oxidation.

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DESPITE the many roles chlorination now plays in the field of sanitation and in industrial practices, always of primary interest to the public health worker will be its accomplishments in the treatment of drinking water since it provides the most nearly perfect means for preventing the spread of water-borne disease. It should be interesting, then, to discuss some recently observed phenomena related to the behavior of chlorine when added to a drinking water supply.For the past thirty years it has been considered satisfactory practice to apply relatively small quantities of chlorine (in the order of 0.05 to 1 p.p.m.) to the water to be disinfected, and to control the application by maintaining a slight residual chlorine content in the water after a reasonably short (generally 10 minutes) interval between the time of chlorine application and performance of the simple colorimetric test by which this residual is determined. It was thought then, that the indication of a residual chlorine content in the treated water after this short time interval showed satisfaction of the immediate chlorine demand, and that additional increments of applied chlorine would result in directly proportional increments in the measurable chlorine residual. In

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NO other process of water purification has had such an astounding growth as the disinfection of water by chlorination. This growth began when bleaching powder or hypochlorite of lime was applied to the Jersey City water supply on a continuous basis at Boonton, N. J., in 1908. The outstanding results obtained with the process and the conditions existing at the time were contributing factors to this rapid expansion.Experiments conducted at the time by eminent water purification and public health authorities such as Professors Mason, Kinnicutt, Park, Westbrook, Drs. Leal and McLaughlin, and Mr. Johnson, on the coliform and typhoid organisms in water gave identical results-in each instance the organisms were destroyed by bleach. To them it was surprising that the small quantities of hypochlorite used were sufficient to kill pathogens.