General description

Location.--Westchester county, on Harlem division of the N. Y. C. & II.

R. R., 64 miles north of New York city.

Population.— 1,050, 90 per cent of which is served with the water.

Waterworks in charge of. Board of trustees.

Source of supply. Brook, 3 miles northeast of village.

Consumption.- 95,000 gallons daily.

Distribution system.― Gravity, 8 miles of mains, 4 to 10 inches in diameter. Service taps.- 175, none of which are metered.

Pressure.-90 to 120 pounds per square inch.

Storage. Impounding reservoir, 30,000,000 gallons.
Purification.— None.

Reference to previous investigations.—Annual Report, Vol. 33, page 794. The previous inspection was made in connection with an investigation of an outbreak of typhoid fever. At that time it was pointed out that general satisfactory sanitary conditions existed upon the watershed of this supply, but that there were several local opportunities for extremely objectionable and possibly dangerous pollution, namely, the direct drainage into the reservoir of washings from pasture land and dressed fields, and the practice of ice cutting on the reservoir. It was, therefore, recommended that the stream tributary to the reservoir be fenced off so as to prevent cattle from entering and polluting the water, and that the spreading of manure on the territory adjacent to the reservoir should be prohibited, or suitable drainage ditches should be constructed in order to divert polluted surface water from entering the reservoir. It was further recommended that the practice of ice cutting be either prohibited or carried on only under the strict supervision of the board of water commissioners, that frequent and regular inspections be made by the water commissioners of the sources of supply and that, should any difficulty be experienced in maintaining satisfactory sanitary conditions upon the watershed, the village authorities apply to this Department for the enactment of rules and regulations.

From the recent inspection it appears that the supply is still open to contamination by surface wash from pasture and cultivated lands, although the practice of ice cutting upon the reservoir has now been prohibited. There is also one house, not mentioned in the previous report, at which there exists certain possibilities of contamination of the supply. This place is located about one-half mile above the intake on the northerly brook. At this place there is a privy about 75 feet from the brook and a barnyard and barn about 60 feet therefrom. With the exceptions noted above the watersheds tributary to the Pawling supply appear to be in a fair sanitary condition for a surface supply.

At times some trouble is experienced with tastes and odors in the water, due to the development of algae growths in the impounding reservoir. It is possible that this trouble might be obviated by the judicious application of copper sulphate to the reservoir.

At the time of the inspection a sample of water was collected from a tap in the village, and the results of the analysis of this sample, together with others made in the past by the Division of Laboratories and Research, will be found in the appended table.

These analyses show a water somewhat colored at times. usually clear, although occasionally turbid and comparatively hard. The figures for nitrogen in its various forms and for oxygen consumed indicate the presence of moderate amounts of decomposing and decomposable organic matter. The total bacterial counts are usually moderate for a surface supply, although at times rather high. Organisms of the B. coli type are present in the majority of the 10 c.c. inoculations and are occasionally present in the 1 c.c. and 1/10 c.c. inoculations, thus indicating the presence at times of considerable active contamination of animal or human origin.

In view of the above facts the following conclusions may be drawn:

1. That the village authorities of Pawling have in part carried out the recommendations made by this Department in 1912.

2. That the supply is, however, still open to animal pollution from pasture land and cultivated fields and possibly to human contamination from the dwellings located upon the watershed and from transient visitors thereto.

3. That the supply is at times subject to tastes and odors, due in all probability to the growth of algae in the impounding reservoir. I would therefore recommend:

1. That the village authorities give their consideration to the previous recommendations of this Department.

2. That in order to preclude the danger arising from accidental, incidental or wilful pollution of the supply by transient visitors to the watershed or by permanent residents thereon, the village install and properly operate some method for the purification of the supply. In this connection sterilization by liquid chlorine might alone be ample to protect the sanitary quality of the supply, although, in view of the trouble experienced at times with tastes and odors, it might be more advisable to subject the supply to filtration supplemented by aeration.

3. That pending the installation of a permanent purification plant and at such times as trouble from algae growth is experienced, copper sulphate be applied to the water in the impounding reservoir under the advice of a competent expert.

4. That should any difficulty be experienced in removing sources of pollution upon the watershed, the village authorities consider the matter of applying to this Department for the enactment of rules and regulations for the sanitary protection of the supply as provided for by section 70 of the Public Health Law.

I would further recommend that copies of this report be transmitted to the local authorities of Pawling and to the sanitary supervisor of the district. Respectfully submitted,

THEODORE HORTON,
Chief Engineer

ALBANY, N. Y., June 26, 1917

RESULTS OF WATER ANALYSES

PEEKSKILL

HERMANN M. BIGGS, M.D., State Commissioner of Health:

I beg to submit the following report upon an investigation of the public water supply of the village of Peekskill, Westchester county, made by Mr. E. S. Chase, assistant engineer, on May 24, 1917.

A

Peekskill is an incorporated village with a population of 15,502, located on the Hudson river, 40 miles north of New York city, on the main line of the New York Central and Hudson River railroad. The village contains several manufacturing establishments and is largely an industrial community. public system of sewers discharges without treatment into the Hudson river. The public water supply of Peekskill is derived after purification from Peekskill Hollow creek, the intake being located about 2 miles northeast of the village center. The waterworks are owned and operated by the municipality and were originally installed in 1875. Changes in pumping equipment, intake works and extensions to the water mains have been made from time to time, and in 1910 four units of slow sand filters were constructed and put into operation. Of the 2,500 services some 90 per cent are metered. The water is pumped from the creek to a storage and sedimentation reservoir on a hill about 1 mile south of the pumping station, whence it flows by gravity through the filter plant to the village. A small amount of filtered water is also pumped to a steel standpipe about half a mile south of the filters, this standpipe serving a separate high service distribution system of small extent. The pressure in the mains varies from 40 to 110 pounds per square inch according to location in the village. The average daily water consumption is approximately 3% to 4 million gallons daily, about a third of which is used for industrial purposes.

The intake at Peekskill creek consists of a concrete dam approximately 15 feet high and 75 feet long, forming a small intake pond of limited area. From a concrete intake chamber provided with bar screens the water flows to the pumping station a short distance below the dam.

The pumping station is a brick building housing a steam pumping equipment. The pumping equipment consists of one Holley pump with a capacity of 3,000,000 gallons daily, two centrifugal pumps driven by water power with a capacity of 864,000 gallons per day each, and one centrifugal pump, motor driven, with a capacity of 900,000 gallons per day. Of the total amount of water pumped during 1916, some 938,000,000 gallons were pumped by the Holley pump, 22,000,000 gallons by the motor-driven centrifugal pump, 259,000,000 gallons by water power and 120,000,000 gallons by one of the water power pumps driven by a Corliss engine. The high service equipment at the filters is 750,000 gallons per day, motor driven, Worthington centrifugal pump. This pump is usually operated about 11⁄2 hours per day.

The 30,000,000-gallon reservoir into which the water is pumped from the pumping station was formed by cut and fill with earth embankments, rubble paved on the inner slopes. This reservoir acts as both storage and sedimentation basin prior to filtration. From this reservoir the water flows by gravity through a small intake chamber, thence through an aerating nozzle into a circular concrete basin, from which it flows upon the filters.

These filters were constructed in 1910 after the design of Hazen & Whipple, consulting engineers. They consist of four units of covered filters 65 by 131 feet in plan each. The filter media consists of 3 feet of sand and 10 inches of graded gravel over underdrains of half round 8-inch tile. The specifications call for sand of an effective size of not less than 0.25 mm. nor more than 0.35 mm. and a uniformity coefficient of not more than 3.0. The water is carried over the beds at an average depth of 4 feet. The loss of head varies from a minimum of 0.3 foot to a maximum of 4 feet. The loss of head through the filters is measured by Simplex gages and the rate of filtration is controlled by hand-operated valves.

The filters are operated for 6 and 8 weeks between cleaning the necessity for cleaning being indicated by the loss of head. At times of cleaning

approximately three-fourths of an inch of the top layer is removed by ejector and washed in a sand-washing machine located over the center of the bed. Clean sand is placed on the filters once a year, the amount of sand having been removed amounting to 10 or 12 inches. Aiter cleaning the first filtrate is wasted for about three-fourths of an hour.

From the filters the water flows through a clear water basin immediately adjacent to the most easterly of the filters and whose dimensions are 95 by 131 feet in plan by 10 feet deep and whose capacity is approximately 900,000 gallons. Analyses of the raw and filtered water are made at monthly intervals by the Lederle laboratories of New York city.

Peekskill creek at the point of intake has a watershed of approximately 47 square miles and an average flow of 40,000,000 gallons daily. There are several ponds on the watershed which act as natural storages but over which the village has no regulation. A large storage resevoir with a capacity of 450,000,000 gallons, known as the Wickopce reservoir, was constructed in 1914 near the headwaters of the creek. This reservoir is owned and controlled by the municipality and can be drawn upon to maintain the flow of the stream. The watershed is of irregular topography, partly wooded and partly devoted to agriculture. The total population may be estimated at 2,000 or 42 per square mile. This population is scattered over the area in isolated farm houses or in small hamlets, no villages or other appreciable centers of population existing thereon. In 1908 a severe outbreak of typhoid fever in Peekskill, which had been investigated by this Department, was attributed to an infection of the then unfiltered supply by a labor camp located on the watershed at the time of the construction of the Catskill aqueduct of the city of New York. Subsequent to this outbreak steps were taken to prevent a recurrence of such an outbreak by the installation of a filter plant. The watershed is also protected by rules and regulations enacted by this Department August 19, 1897. For the enforcement of these rules the village employs an inspector who visits various portions of the watershed every day during the year either by motorcycle, on foot or by driving.

Subsequent to the time of the inspection samples of both raw and treated water were collected by Dr. E. DeM. Lyon, health officer, and the results of the analyses of these samples together with others made in the past by the Division of Laboratories and Research will be found in the appended table.

The results of these analyses show a raw water with high color and slight turbidity. The figures for hardness are moderate and somewhat variable. The total bacterial counts in the two samples of raw water are high and the presence of organisms of the B. coli type in inoculations as small as 1/10 .c. indicate active contamination of animal or human origin. The analyses of the filtered water indicate that the purification process brings about a removal of turbidity and a marked reduction of color. The total numbers of bacteria in the filtered water are usually moderate or low and only occasionally are organisms of the B. coli type present and then in large inoculations. In view of the above facts, it may be concluded that the public water supply of the village of Peekskill is of a reasonably satisfactory quality, due to the purification brought about by the filtration plant. There seems to be therefore no necessity at this time of making any recommendation other than that the village authorities continue to maintain careful oversight of the sanitary conditions upon the watershed and to continue efficient operation of the purification plant.

In conclusion, I would recommend that copies of this report be sent to the local authorities and to the sanitary supervisor of the district. Respectfully submitted.

ALBANY, N. Y., August 20, 1917

THEODORE HORTON.
Chief Engineer