Detroit, after considerable discussion, removed their source of supply three miles above the city, and constructed new works in preference to expending more money on the old works.
Rochester, N. Y., expended 4½ millions for bringing the water of Hemlock Lake thirty miles to the city.
Baltimore celebrated only last October the opening of their new aqueduct, conveying the waters of Gunpowder River 7 miles in distance, at a cost of over four millions.
Indianapolis has been compelled to erect new works owing to the contamination of the present source.
CHAPTER III.
PURIFICATION OF WATERS.
The Rivers Pollution Commission of 1874, says, as regards filtration: “No process has yet been devised for cleaning surface water once contaminated with sewage, so as to make it fit for drinking.” Others say it is not safe to trust to dilution, storage, agitation, or filtration for periods of time, for the complete removal from water of disease-producing elements whatever they may be.
Dr. Frankland states:
“I believe the noxious parts in sewage is that which is held in mechanical suspension, not held in solution. I would not say it is impossible to remove it, but no system of filtration will secure its removal. There are only two processes by which it can be effectually removed—one by boiling for a long time, and the other by distillation.”
The methods adopted for filtration of water are: