At Hackensack Water Company, New Jersey

Abstract

causes such as decaying organic matter, in the manifold forms in which this occurs, and those odors and tastes that enter the supply through pollution. In the second class we find odor troubles arising from decomposing sludge in settling and coagulation basins and from stagnation in dead ends or other parts of distributing systems where circulation is poor and excessive oxygen depletion takes place. Recent work seems to indicate that electrolysis from stray currents may constitute another source of odors and tastes developing in distributing mains, service pipes and meters. In any discussion of odor troubles it is well to point out that such difficulties are likely to be more pronounced in hot water systems employing storage tanks than in the cold water directly from the mains. This is particularly true where the odor producing substance is one of the volatile hydrocarbons of the benzene ring series. Furthermore, there must be a high degree of removal of such substances from water as small amounts, hardly detectable in the cold supply, become concentrated in the upper portions of hot water boilers. As the hot water is drawn off intermittently the first portions contain a high concentration of the contaminating substance. The diversity in character and treatment of water supplies throughout the country is so great that odor and taste control becomes, in considerable degree, a matter for local solution. In that large group of water systems comprising the surface supplies, with treatment plants, there are common problems however which are being successfully overcome by one or more of the several agents now available for odor elimination. Introduction of the latest of these substances activated carbon several years ago focussed attention upon the whole subject of odor control in water supplies as a matter not to be side-stepped but to be attacked vigorously. Successful application of this material in preventing odors from decomposing sludge in coagulating basins has made it possible to eliminate one of the most