Filtration at Detroit
In the report furnished to the water board of Detroit, Mich., recommending the installation of a $2,500,000 filtration plant for the city, are given the details of a tour of inspection of various cities that have installed such a system, made by the writers. These claim that the raw water furnished to Toronto, Pittsburgh and Cincinnati is of inferior quality to that of Detroit, coming as it does from lake or river, yet after filtration it is superior to the raw water that forms the potable water of the last-named city. During the flood at Pittsburgh and Cincinnati the water works plants had no difficulty in furnishing practically clear water, and in each of these cities deaths from typhoid due to water supply have been practically eliminated. Two cities visited are using slow sand filtration, and one mechanical; all. however, are supplemented by chlorination. The report says that either type of filter would operate satisfactorily; “but, it adds, “it appears that the mechanical filter can be installed at a much less first cost, with consequent less fixed charges, can he more economically operated, will require less ground area, can hr extended in size more easily, and ran be more quickly installed than the slow sand filter.