FILTRATION AT PHILADELPHIA.

FILTRATION AT PHILADELPHIA.

William Barclay Parsons has resigned as one of the commission of experts which is investigatthe filter contracts, in consequence of his being obliged to leave for Panama, where his services are required as a member of the board of consulting engineers of tne Panama Canal Commission. Mayor Weaver will not fill the vacancy thus caused, as he is well satisfied with the progress that was being made by Major Gillette and J. Donald Maclennan, the other members of the commission. The final report of the commission, it is expected, will be received in a very short time. The investigation of the filter beds of the Torresdale plant must be finished before the beds can be used. Measures will be adopted to raise the water from the Delaware to some of the filter beds by the installation of temporary pumps on the banks of the river near the beds. The operation of the plan depends entirely on the condition of the conduit. If the investigation of the interior of the conduit proves it to be serviceable, the plans will be put into effect as soon as possible. The water, when it leaves the filter beds, will flow by gravity through the conduit to Lardner’s Point, wnen the pumping station will send it to the consumers through the Frankford mains. The rate will be only 40,000,000 gallons a day, which is the amount of water now being supplied to that territory. It would not be possible to send the filtered water to any other part of the city, as the system of distributing mains which will connect the pumping station with the city mains is not completed. The Torresdale intake will not be moved to a point about twenty-four miles up the Delaware river. Such a plan was suggested, because the water from the upper Delaware was found to be much purer than at Torresdale. The proiect contemplated running the water to Torresdale in a canal to be built twentyfour miles long, at an estimated cost of $9,000,000. The pumping machinery to be installed will have a daily capacity of 3,000,000 gallons. The capacity of the conduit is 9.000.000 gallons, which, at the rate specified, could be pumped out in four or five days.

QUINCY COMPOUND, HIGH-SPEED ENGINE OPERATING CENTRIFUGAL PUMP, TERRE HAUTE.

FILTRATION AT PHILADELPHIA.

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FILTRATION AT PHILADELPHIA.

In a recent address, delivered before the Union League, of Philadelphia, at the Torresdale filtration plant, Chief Engineer John W. Hill, of that city’s bureau of filtration, gave a very interesting sketch of what is being done at the Torresdale and other filter plants for the citizens of the Quaker city. Among other things he said that “the original capacity of the Torresdale filters will be 248,000,000 (in round numbers 250,000,000) gallons per day, and sufficient land was taken and is available to increase the capacity of that station, if need be, by 200,000,000 gallons more. Thus the works as outlined, without anticipating any changes or additions to Roxborough, will have an ultimate total capacity of 577,000,000 gallons, or more than the amount provided by the new works proposed for the cities of New York and London, in each of which cases the maximum capacity thus far discussed in speculating upon the future requirement is limited to 500,000,000 gallons per day. The lower Roxborough station draws its water from the old Roxborough reservoir, which has a capacity of about 13,000,000 gallons, and represents about one day’s supply when the filters are operated at the rate of 12,000,000 gallons per day. This station is provided with a system of preliminary filters, and, when the works are operating at the rate of 12,000,000 gallons per day, the final filters will be run at the rate of 6,000,000 gallons per acre per day. In order to demonstrate conclusively the ability of the bureau to operate the filters at the 6,000,000 gallon rate, one or more of the filters are maintained at or near this rate at all times, notwithstanding the quantity of water drawn from the station at the present time is not up to its capacity. The upper Roxborough station draws its water from the new Roxborough reservoirs, from which it is lifted to the filters by low-service pumping machinery in the annex to the Roxborough auxiliary pumping station. These works have an easy capacity of 20,000,000 gallons per day, but, due to lack of pumping facilities at the Shawmont station, it is not possible to run either the upper or lower Roxborough works at their rated capacity, and thus, instead of furnishing 32,000,000 gallons per day at the present time, we are supplying only 17,000,000 gallons per day. It is hoped that the condition of the pumping machinery will be improved in due time. The Belmont filters, without the preliminary filters, are shown to have a capacity of 33,500,000 gallons, but, with the addition of preliminary filters (one installation of which is now under construction, contract No. 39) the capacity of the present system of plain sand filters will be raised to 65,000,000 gallons per day, and, when it may become necessary to increase the capacity of the station beyond the latter amount, sufficient land was taken upon which to build eight additional plain sand filters, each of 0.75 acre area, at which time, with the further addition of 30,000,000 gallons of preliminary filter capacity, the Belmont works can easily supply 95,000,000 gallons per day.” The daily capacity of the different filtration works—those now in operation at lower and upper Roxborough and Belmont, and those under construction at Torresdale—is as follows: Roxborough works: Lower Roxborough, 12,000,000 gallons; upper Roxborough, 20,000,000—Roxborough capacity (both stations), 32,000,000 gallons; maximum available pumping capacity of the Shawmut pumping station, 17,000,000 gallons—showing a deficiency of 15,000,000 gallons. Apportioning the Roxborough filters to the capacity of the pumps at Shawmont: Lower Roxborough, 8,000 gallons; upper Roxborough, 9,000,000—Roxborough available capacity (both stations), 17,000,000 gallons. Belmont works: Belmont (without preliminary filters), 33,500,000 gallons; Belmont (with preliminary filters), 65,000,000; Belmont preliminary filters, first installation, 40,000,000 gallons. Torresdale works: Torresdale (fiftyfive filters), with preliminary filters, 210,000,000 gallons; Torresdale—Queen Lane Contingent (ten filters) with preliminary filters, 38,000,000 gallons — Torresdale total, 248,000,000 gallons. Recapitulation.—Present capacity of Roxborough filters, due to capacity of pumps at Shawmont, 17,000,000 gallons; Belmont, with preliminary filters (present daily capacity), 40,000,000; Torresdale, with preliminary filters (present daily capacity). 248,000,000—Total, 305,000,000 gallons: add additional to Roxborough, 15,000,000—320.000,000 gallons. The probable actual average daily consumption cannot be less than 280,000,000 gallons. According to the bureau of water, the average consumption was 314)000,000 gallons. The Torresdale filters have been located with regard to the possible introduction of water from impounding sources of water supply on the Delaware, Lehigh, Tohickon and Neshaminy watersheds, should conditions in the future suggest the advisability of abandoning the intake at the Torresdale filters, and drawing the water from very large storage basins located on the watersheds mentioned. The elevation of such basins would be such as to deliver the water by gravity to the Torresdale filters, and, if the physical conditions of the water source or sentiment, of the people in the distant future demand a change of the source from which the raw water is drawn, no portion of the Torresdale filtration works would be lost at that time, excepting the pumping machinery and station for the lifting of the raw water from the Delaware river to the preliminary filters, and even if the water were drawn through long aqueducts from these distant sources, it is a question whether it would not be advisable to maintain always ready for service the low-service pumping machinery at Torresdale, in case of accident to the aqueducts or depletion of the storage sources of supply. From this point of view no portion of the work that is now being carried out under the general title of the Torresdale filters would be abandoned, even should the water in . the future be drawn from the Delaware Water Gap, or some other distant point. It is a fact that the cases are rare where surface water can be gathered in large basins and delivered in a satisfactory condition to the consumers; and, even though the water were drawn from impounding reservoirs on the watersheds of the Lehigh, Delaware, Tohickon, and Neshaminy watersheds, Chief Hill’s opinion is that it would not be fit for drinking purposes until it was filtered. The cost of constructing and operating a system of filters for the removal of sewage pollution from river and lake waters is not affected by the degree of pollution—i. e., the cost of constructing and operating filters, arranged to take water from the Delaware river at the Water Gap, would probably be no less than the cost of building and operating filters to take water from the Schuykill and Delaware rivers within the city limits, nor is it believed from a study of the operation of the Roxborough and Belmont filters, that any better results in point of bacterial and turbidity contents would be obtained even though the raw water as it comes from original sources were superior to that drawn from the Schuykill and Delaware rivers. In fact, it is anticipated that, after the raw water has passed through the preliminary or roughing filters, it will lie equal or superior to water carried for some length of time in large impounding reservoirs, or that the water as it leaves the preliminary filters would be quite as fit for general domestic use as that to be obtained either from the Delaware river at the Water Gap or from large storage reservoirs that might be constructed upon the watersheds of the streams in Pennsylvania discharging into the Delaware river, which have been from time to time under consideration for the purpose of public water supply. (Of course all water after leaving the preliminary fillers, will be passed through the plain sand filters before going to the Philadelphia consumers.) As to the cost of water from the Delaware Water Gap: The estimated cost of construction, for a daily supply of 200,000,000 gallons from the Perkiomen and Lehigh river tributaries, would be $33,410,000. Assuming that an increase of the supply to 300,000,000 gallons per day (such as is now being provided for by the improvement, extension and filtration of the water supply), would have cost fifty per cent, more, this would represent a possible outlay of over $50,000,000. For a daily supply of 200,000,000 gallons from tributaries of the Delaware river near the Water Gap, the cost was put at $47,540,000, and assuming that, if the supply should be increased to 300,000,000 gallons per day (as is now being provided for as above), the cost would be fifty per cent, more; then this scheme would have caused an outlay of over $70,000,000. An interesting feature with reference to reservoirs and tanks forming part of a works of filtration has been the attempt to secure as nearly as possible watertightness. Realising that a filter tank 200 feet long by 135 to 140 feet wide, carrying water for a depth of nine feet, could not be as tight as a glass bottle, a standard of, leakage was fixed to which the filters were required to comply. This was 1,000 gallons per day for a .75 acre filter, and the leakage test was carried through a period of at least fourteen consecutive days, during which time careful gaugings were made of the loss of water in the filter with proper corrections for weather changes. Of the fifty-five filters in the first installation at Torresdale, nineteen showed an average loss in twenty-four hours of 244 gallons per day; fifteen an average loss of 488 gallons; fourteen, 732 gallons; 2, 967 gallons in twenty-four hours; hve, no loss whatever—i. the leakage, if anv, was so small th.at it could not be measured with 11 guages. The average leakage for all filters was 439-2 gallons in twenty-four hours —less than half of what was regarded as a fairly allowable leakage for structures containing many thousand lineal feet of mortar joints, and depending almost entirely upon a twelve-inch thickness of puddle for watertightness in the bottom Improvement, extension and filtration of the water supply of Philadelphia, for the total amount provided by loans and appropriated bv councils was $22,500,000; completed and uncompleted contracts and cost of maintaining bureau to date, $20,770,500—balance available $1,720 500. Fo complete Belmont Laboratory $1500 To complete Torresdale low service pumping machinery and station: Filtering materials (including Queen Lane Contingent), sand washer pumps electric lighting equipment, coal handling equipment and pockets, shelter houses, $1,615,265.41. Loal-handlmg equipment and pockets, suctionconnections to No. 1 pumping station, $77,500. Removal of pumping machinery from Queen Lardners Point: Removing machinery to Lardners Point, remodeling Queen Lane pumps $130,000,00—Total, $1,824,265.41.

WATER TOWER EXTENDED.

Concluded on page 12.

Concludod from page 11.