INDIANAPOLIS WATERWORKS SYSTEM
The city of Indianapolis, which was founded in 1819, has a stream, the White river, flowing adjacent to its borders. From this source the city was first supplied with water. It is one of the few large cities whose waterworks system is owned and operated by a private company. The plant was constructed in 1870, when the city had a population of 30,000. In 1880 the works were sold at a sheriff’s sale and were purchased by the Indianapolis Water Company, who improved the system according to plans by J. J. R. Croes, C. E., of New York. The supply is furnished through a filter gallery on the White river and distributed by direct pumping. The gallery is 2,000 feet long, partly covered and partly open, and is located about one and a half miles from the pump well. The water was first taken from two wells near the river. They were 20 feet in diameter and 80 inches apart and sunk 10 feet below low water in the river and connected by a tunnel. In one of the wells a 4-inch pipe was driven 80 feet, but this proved inefficient, and the water was subsequently drawn directly from the river. As drainage from the buildings along the banks of the river passed into the intake pipe, the water became polluted so that in 1879 a crib was sunk in the river, filled with stone, with a gravel covering. It was 25 by 50 feet and 4 feet high, and had a suction pipe connecting one end. The crib was supposed to provide filtered water, but in a year after its construction it broke, and the sand was taken into the pipes through the whole system. The pumping machinery at this time consisted of a Holly engine of 22,000,000 gallons daily capacity. This was subsequently increased by another Holly-Gaskill pump, driven by water power of 10,000,000 gallons capacity.
Later on the company erected a handsome new pumping station and installed a Snow triple-expansion engine of 20,000,000 gallons capacity with adequate boiler equipment. An illustration of this building is given herewith. The gallery was improved until it had an average width of 40 feet, and six artesian wells were driven 450 feet deep to increase the flow of water through it. The filtering bed in the river was also improved, so that the quality and quantity of water proved efficient. A short time ago the company constructed a modern filter plant, which has given considerable satisfaction. The illustrations show the principal features of the filtration plant. The new pumping station is 77 feet by 45 feet inside, while the foundation is 25 feet deep and consists of 3 feet of concrete laid under the entire building. The station proper has a steel frame, and the walls are 18 inches thick and 52 feet above foundation.
The new filtration plant has already been described in detail in this journal, but the following brief description may prove interesting at the present time. White river is the principal source of supply, the water being impounded at Broad Ripple by a dam built by the State of Indiana and maintained by the Indianapolis Water Company. The dam is 8 ft. high and backs the water up the river about four miles. The comb of the dam is 32 ft. above the low water in White river in the city. From this point the water is diverted to the head-gates of the canal. Before entering the raw water line the water passes through fine racks and sponges in the intake house, which keeps floating matter off the beds. From the intake house the water flows through a 48-in. castiron pipe-line to the basement of the laboratory, where it flows upward through large cast-iron cylinders having cages filled with sponges, and then on through the conduit by gravity to the filterbeds. There are arranged in the laboratory building a duplicate set of centrifugal pumps, having a capacity of 20,000,000 gals., that can pump water from Fall creek whenever the water is out of the canal. This gives the company three sources of supply—namely, White river, Fall creek and its system of thirty 8-in. and 10-in. wells, with compressors furnishing 8,000 cu. ft. of free air per minute, for lifting the water from the wells, which are used in case of necessity. The aqueduct, which it was necessary to construct to convey the water over Fall creek, is 290 ft. long, 36 ft. broad and 5 ft. deep, and is quite a fine structure. This aqueduct and one in France, form, it is believed, the only ones of the kind made of concrete. To the water company there were objections to some features of the construction of slow sand filterbeds as ordinarily built. One was the open-joint, round underdrain tile. In this construction it is absolutely necessary for the water to flow from the centre of the tile to the open joint. The tendency of the water to this common opening produces unequal drainage coursing of the raw water, and the result is an unequal surface of the beds and not an altogether satisfactory effluent at all times. To avoid this difficulty the company adopted a perforated tile having 5/8-in. openings. There are about 1,000,000 of these perforations in each of the filterbeds, being spaced about 2 1/2-in. apart over the entire bottom. The arrangement of the filtering medium is practically the same as at other plants—namely, 1 ft. of graded gravel and 3 ft. of fine sand. The sand used was taken from Fall creek, near the filter plant, and, while not as uniform and fine as some cities have, the results have been equally as good, if not better. The beds were originally 200 by 350 ft., and contained about 70,000 sq. ft. Since the original construction a division wall has been put in— making the area of each bed about 35,000 Sq. ft. This was done, so as not to have such large units out of service when cleaning, and to furnish a support for the roof. There was no other objection to the size of the bed. The filtration from the large bed was just as good as from the small bed. The action of the wind and sunlight on water is unquestionably beneficial, but the sunlight causes vegetable growths, which are very undesirable, and then, again, the ice forms upon the beds in winter and makes it difficult and expensive to clean them. To avoid these troubles the beds were covered with 3-in. concrete and steel rods. Upon this cover is placed 2 ft. of cinders. The supports of the roofs of the beds are 7-in. cast-iron columns, with flanges 8 in. apart, of different depths, so as to prevent the raw water from finding its way down the columns. The walls of the beds are stepped off for the same reason. The advantage of the columns, either iron or cement, is the saving of space in the beds over the groined arch. All the walls of the beds and clear-water basins are concrete, with steel reinforcement. In the roof of the beds steel I-beams were used, so that there are both concrete and steel beams. The concrete, however, are preferable. No advantage has been found in the steel I-beams, covered with cement, over the concrete beams reinforced with steel rods. The bottom of the bed is made of 6-in. concrete laid upon rolled clay. On this is laid, in cement, the tile, with perforated top, the joints being filled with cement. The tile are 2 ft. long and 12 in. wide, with division walls making conduits 3 in. by 5 in. The tile support the material forming the filterbed, and are laid end to end across the bed and through and into the bafflewalls, forming the collecting gallery on the right, and the washout gallery on the left. Hose placed in the tile in the collecting gallery will force any sediment in the tile to the other side of the bed and into the washout gallery. These galleries have manholes, and, when the bed is drained for cleaning, they allow the air to pass under the bed and up through the gravel and sand. The galleries can be entered and the walls washed down. All parts of the underdrain system are accessible and easy of examination. It will thus be seen that there must be uniform filtration from every portion of the bed without coursing. The water flows from the collecting galleries into the clear-water storage basins through a 30-in. pipe, which conveys it to the far end of the clear-water basin—a distance of 300 ft.—where it is discharged. The purpose of conveying the water to the far end of the storage basins and then discharging it, is to keep the entire body in motion, thereby preventing any possibility of stagnation. From the filterbeds the water is taken through meters to the clear-water basins. In the regulating houses are all the latest devices for measuring the quantity of water discharged per day from each filterbed, showing the friction losses from day to day, and regulating the operation of the beds as to the rate of filtration. The regulating houses are connected with the clear-water basins and the 48-in. conduit line leading to the Riverside pumping station. The 48-in. conduit-line is made of concrete reinforced with steel, and is nearly 6,000 ft. long. From the conduit-line the water is discharged by gravity into a receiving well, from which suction-mains are laid to the pumps. The filterbeds, as constructed, have an entrance at each end, each entrance serving for two beds and being located on the dividing walls. This arrangement proves very convenient for cleaning and recharging. The sand, when taken off the bed, is washed and stored in concrete bins, no other handling being necessary than the scraping of the beds. The scraped sand is transported by water under pressure by means of a portable Korting ejector and sand-washer. The sand on the beds is made as level as a floor, and when the water is drawn off for cleaning, the surface of the bed is just as perfect as before the water was turned on. When filling the beds, after cleaning, the filtered water front the clear-water storage basin is introduced from below, through perforated tile, and rises up evenly through the sand until the surface of the bed is covered, to a depth of a few inches. Raw water is then turned on to the bed to a depth of 4 1/2 feet above the sand, when filtration is started at a low rate per day until, by bacteriological examination, the effluent shows the water to be potable. The bed is then put into service at from 3,000,000 to 4,000,000 gals, per day per acre. The water as it comes from the filterbeds is bright and sparkling, as beautiful as spring water, and of a high degree of purity. The beds, inlets, outlets, conduit and receiving wells are entirely free from odor. The clear-water basins are 70 by 350 ft., with a depth of 16 ft. 2 in.; capacity, 2,500,000 gals. They are covered with a concrete roof, supported by concrete columns and concrete girders reinforced with steel. Upon this roof was laid a track upon ties (rails weighing 70 lbs. to the yard) and as many as five dump cars, each hauling 3 yds., have been upon the roof at one time. The valves in the clear-water basin are so arranged that water can be stored and the minimum or maximum amount taken out of the basin.
The sixteenth annual meeting of the American Water Works Association was held in Indianapolis in 1896, at which time the new pumping station had just been completed. The members of the association made a close inspeciton of the building and pumping plant, and it was then regarded as one of the most complete of its kind in the country.
Since that time considerable improvements in all lines of work connected with the plant have been made, so that those who visit the Central States convention and were present in 1896 will realize what great strides have been made to keep the plant up to the proper standard consistent with the great increase of the population of the city. The distribution system at the present time consists of 309 miles of cast-iron mains, 40 to 4 inches in diameter; 2,585 Mathews hydrants, and a proportionate number of valves of the Eddy and Darling types. There are 33,000 services in the system, and the pressure is maintained at an average of 55 pounds, which may be increased to over 100 pounds for fire service. Last year the annual consumption was 6,300,000,000, or an average of 17,400,000 gallons per day. Out of the large number of taps there are only 2,560 meters of the following brands: 559 Crown. 43 Union Rotary, 97 Trident, 178 Hersey Disc, 485 Thomson, 9 Worthington Disc and 188 Keystone. The financial standing of the company is first class, but no report has been made of the exact figures. The officers of the Indianapolis Water Company are: L. C. Boyd, president; H. McK. Landan, vice-president and treasurer; F. C. Jordan, secretary, and L. C. Boyd, superintendent. The present mayor of the city is C. A. Bookwalter, and Blaine H. Miller is city engineer.
Notes on Filtration.
The property of the American Filter Company at Shamokin, Pa., has been sold. The new owners will reorganize the company at Johnstown with a capital of $100,000.
Because a creek, used as an open sewer, empties into the Wabash river one mile above the intake at the pumping station, Vincennes, Ind., may be compelled to install a filtration plant.
It is possible that La Porte, Ind., will follow the example of Milwaukee, Wis., and Marquette in the treatment of water with hypochlorite of line. The precaution would prove to be a wise one, at least until the extension of the intake pipe has been accomplished.
The finding of the baccillus coli has revived the question of the filtration of water used by the citizens of North Birmingham, Ala. The health officer. Dr. R. B. Harkness, will make a recommendation at the next meeting of the council that either a filtration plant be constructed or the source of the infection of the water located and remedied.
The water inspection committee delegated by the city council to inspect the filtration plants of other cities before definite action is taken toward installing a plant in Fargo, N. Dak., will soon start for Toledo, Ohio. From there, it is said, the committee will go to Pittsburg, Pa., where a mechanical filtration plant was recently installed. No report will be made to the council until the report is complete.
When filtration becomes necessary for Akron, Ohio, slow sand filters could be located on land owned by the company near the pumping station, according to the theory of W. E. Bemis, a consulting engineer. These filters could have a water surface at elevation of about 960 feet and would be supplied by gravity through a 48-inch main. The main from the east reservoir can be so laid as to discharge 20,000,000 gallons per day at a point 5 feet above the ground level at the pumping station. This would permit a 10-foot loss of head in the filters, and still have the bottom of the filter beds only 5 feet below the ground level. When a larger flow than 20,000,000 gallons is desired, it will be cheaper to secure it by low lift pumps, raising the water from the pump wells into the filterbeds, than to build the filters at such low elevation as to secure a larger flow than 20,000,000 gallons by gravity.