PURE WATER FOR PARISIAN SUBURBS.
In 1891 Paris was visited with an experience of cholera, the severity of which in the suburban portion of the city was clearly increased by the evil quality of water supplied the 700,000 people who inhabit these districts. These depend solely upon the Seine for all the water they drink, and that river is so polluted by the factories along its banks and by the sewers and drains that discharge into it as to render it foul and unwholesome—a source of disease to all who use it. This evil is now in process of being amended, and a system has been adopted for the purification of the water—or, at all events, for purifying it in a very large degree. On the recommendation of M. Hetier, chief engineer of the Department de la Seine, the Conseii d’Hygiene has approved the method of purifying by Anderson’s process, which has been tested at Boulogne by the Compagnie Generale des Faux. The expense is to amount to I2,cco,ooof. for all the suburbs; the company agrees to pay 7,6oo,ooof. provided that the remainder, 4,400,ooof., is contributed by the suburbs in annuities of 28o,ooof. during thirty-five years. Out of fiftynine suburbs, fifty-eight have adopted the arrangement, but Saint Denis, which is supplied byartesian wells, still hesitates. The purified water will cost only ic. more per cubic metre, that is, an average of 34c.
The water to be purified will be sent into iron cylinders provided with a slow movement of rotation, in which it will be brought into contact with finely divided particles of iron. The water, when brought into contact with the iron and with air blown in in a contrary direction by ventilators, will be freed from a portion of its organic elements, which, by combining with the iron salts, produce a substance like glue, which surrounds and carries off neariy all the impurities of animal origin and a large proportion of the bacteria. When this first operation is finished, the water flows over a series of cascades in order to increase the imu tnt of air that it can contain, and, after having allowed to settle in decanting reservoirs the corpuscles which it holds suspension, it finally reaches the filtering basins, whose bottoms are formed of thick layers of sand. The workingof this purifiratory method will be watched with interest in this country as, if the system is successful, it is one that could be applied equally well to rivers and streams in the United States.