The filters were designed to remove from the water the bacteria which cause disease. They have already reached a bacterial efficiency of over 99 per cent, and it is expected that their use will result in a great reduction in the death-rate from water-borne diseases in the city. They also remove a part of the color and all of the suspended matters and turbidity, so that the water is satisfactory in its physical properties.
The filters have reached with perfect ease their rated capacity, and on several occasions have been operated to deliver one third more than this amount; that is to say, at a rate of 4,000,000 gallons per acre, daily.
COST OF CONSTRUCTION.
The approximate cost of the filtration-plant complete was as follows:
| Land | $8,290 |
| Pumping-station and intake | 49,745 |
| Filters and sedimentation-basin, with piping | 323,960 |
| Pure-water conduit and connection with Quackenbush Street pumping-station | 86,638 |
| Engineering and minor expenses | 28,000 |
| Total | $496,633 |
The filters, sedimentation-basin, and pure-water reservoir are connected in such a way as to make an exact separation of their costs impossible; but, approximately, the sedimentation-basin cost $60,000, the pure-water reservoir $9,000, and the filters $255,000. The sedimentation-basin thus cost $4,100 per million gallons capacity; and the filters complete cost $45,600 per acre of net filtering area, including all piping, office and laboratory building, but exclusive of land and engineering.
ACKNOWLEDGMENT.
The general plan and location of the plant were first conceived by the Superintendent of Water-works, George I. Bailey, M. Am. Soc. C. E., and the successful execution is largely due to his efforts. The members of the Water Board, and especially the Construction Committee, have followed the work in detail closely and personally, and their interest and support have been essential factors in the results accomplished. In the designs and specifications for the pure-water conduit the author is greatly indebted to Emil Kuichling, M. Am. Soc. C. E., and also for most valuable suggestions relative to the performance of this part of the work. To William Wheeler, M. Am. Soc. C. E., of Boston, the author is indebted for advice upon the vaulting and cross-sections of the walls, and these matters were submitted to him before the plans were put in final shape. All the architectural designs have been supplied by Mr. A. W. Fuller, of Albany. W. B. Fuller, M. Am. Soc. C. E., as Resident Engineer, has been in direct charge of the work, and its success is largely due to his interest in it and the close attention which he and the assistant engineers have given it.
FOOTNOTES:
[1] The American gallon is 231 cubic inches or 0.8333 of the imperial gallon. In this work American gallons are always used, and English quantities are stated in American, not imperial, gallons.