Norwood annual report 1915-1922, Part 66

Author: Norwood (Mass.)
Publication date: 1915
Publisher: The Town
Number of Pages: 1954

USA > Massachusetts > Norfolk County > Norwood > Norwood annual report 1915-1922 > Part 66

Note: The text from this book was generated using artificial intelligence so there may be some errors. The full pages can be found on Archive.org (link on the Part 1 page).

BAND CONCERTS

The open air concerts given by the Norwood Band during the summer months proved to be extremely popular. The programs rendered were of a high order and were enjoyed by large and appreciative audiences.

They should be continued again in 1920.

Respectfully submitted,

W. P. HAMMERSLEY, General Manager.

REPORT OF LEWIS D. THORPE

Boston, Mass., January 17, 1920.

Mr. W. P. Hammersley, General Manager, Norwood, Mass.

Dear Sir: -

I submit the following report upon an additional water filter and pump- ing machinery at the Westwood Station. Force main to the standpipe and cast iron siphon for the sewerage system, together with estimates of cost : -

125

Filter

The present filter was constructed in 1914. It is of the slow sand filtra- tion type, having an area of 13,000 square feet. The inside dimensions are 130 feet in length by 100 feet wide. The walls and bottom are con- structed of concrete. A main collecting drain is laid on the bottom through the center, to which lateral drains, running at right angles, are connected.

The main collector conveys the filtered water into a regular chamber from which it passes into the clear water well. All of the drains are vitri- fied pipe and surrounded with screened gravel. The gravel is in three layers of different sizes and extends over the entire bottom of the filter. The total thickness is 17 inches. Over the gravel is placed three and one- half feet of sand.

Clear Water Well

The clear water well is located at the end of the filter near the pond.

It is 98 feet in length by 48 feet wide and 10.5 feet deep. The capacity when full is 370,000 gallons.

Capacity of Filter

The filter is designed to work at a rate not exceeding four million gal- lons per acre per day, and when working at this rate the capacity is 1,300,- 000 gallons per day. Provision is made for aeration of the water before it passes onto the filters.

The regulating chamber through which the filtered water passes into the clear water well is also designed to contain an aerating pan. This pan has not yet been installed.

The water is pumped from the pond through the aerating pan onto the filter with one of the original pumps. After passing through the filter into the water well, it is pumped into the force main leading to the standpipe.

At the time the filter was constructed it was not expected that it would be necessary to use it during the winter months and no provision was made for covering.

That the filter has given good results is shown by the following analysis of the raw or pond water and filtered water as taken from the report of the State Board of Health.

ANALYSIS OF WATER Buckmaster Pond (Parts in 100,000)

Appearance

Odor

Residue on Evaporation

Ammonia

Nitrogen as

Date of Collec- tion

Turbid- ity

Sedi- ment

Color

Total

Loss on Ignit'n

Free

Total

Dis- solved

Sus- pended

Nitrat's

Nitrites

Hardness

Iron

1918 1919

V. Slight V. Slight

.22 .20

Faintly vegetable earthy and unpleasant

4.00 4.25

1.78 1.80

. 0220 .0048

.0195 .0285

.0159

. 0036

. 36 . 45

.0080

.0003|

0.7 .061 Average of 2 samples 1.4 .037 Average of 3 samples

Filtered Water

1918 1919

| V. Slight | V. Slight None None

.18

None None

5.30

....

1.0044 .0134 .0015 .0139

. 44 . 45

....

1.01.040|One Sample 1.7 .018 Average of 3 samples

Improvement in filtering water in 1919 due to regravelling of the filter bed early in the year.

126

.0910|

.0013}

.11

3.97

Albuminoid

Chlorine

127

With the exception of the time necessary for cleaning, it has been in almost continuous operation whenever this supply has been used.

Time Necessary for Cleaning

I am informed by you that the average time between cleanings is 136 hours of actual use and that the total amount of water pumped during the above period is approximately 8,300,000 gallons. The surface of the sand in the filter then becomes clogged with sediment and it is necessary to draw the water off and allow the sand to dry out before cleaning. Your Superintendent informs me that the filter is out of commission on an average of three days each time that it is cleaned.

During the time necessary for cleaning the supply is taken from the Ellis Station, but if it so happens that there is a shortage of water at the station, or should the pump be out of commission, the supply or a portion of it must be pumped from Buckmaster Pond directly into the standpipe.

On two recent occasions when it became necessary to pump direct from the pond, there has been complaint from the consumers regarding its quality.

In order to provide filtered water at all times, another filter should be constructed and used in connection with the present one. The two filters should be used alternately and during the period that one is in operation the other would have a chance to dry out and be cleaned if necessary.

By the use of two filters far better results can be obtained than is possi- ble with one filter. They will be easier to operate, particularly during the winter months and the cost of maintenance will be less than it is at present.

Location of New Filter

The new filter should be located on the northerly side of the present filter. It should extend from the present clear water well to a point about 15 fcet from the street. The northerly wall of the present filter for a dis- tance of 130 feet would form the division wall between the two filters. The area would be the same as that of the present filter, or 13,000 square feet.

The present clear water well would be used in common for the two filters, and it will not be necessary to construct a new one. This will simplify the piping connections and the plant will be more easily operated than would be the case if another well were constructed.

Pumping Machinery

The present pumping machinery consists of two sets of M. T. Davidson Company simple double acting steam pumps. Each pump has a capacity of one and one-half million gallons in 24 hours.

One pump was installed at the time the water system was constructed and the other at a somewhat later date. They are both of the low duty type.

Boilers

There are two boilers, each 5 feet in diameter by 16 feet long. One was installed in 1897 and the other in 1904. The steam pressure allowed is 100 pounds. Originally both pumps were used for the direct service, or for pumping into the distributing system of the town.

At the time the filter was constructed the pump located in the basement was connected to the filter and used to pump the pond water onto the filter. The connections were made in such manner that by opening or closing certain gates it could be used either for the filter or for the direct service into the piping system of the town.

The suction of the other pump was connected to the clear water well of

128

the filter and used to pump into the distributing system entirely. This pump can also be used to pump direct from the pond into the tower should it become necessary.

When using the filter both pumps are in use at the same time and in case of an accident to either it is necessary to discontinue the use of the filter until repairs can be made.

Coal Required for Pumping

During the year 1919 the total amount of water pumped from this station as shown by pump displacement was 143,398,000 gallons and the total coal used was 382 net tons. This would mean a station duty of about 31 million foot pounds for each 100 pounds of coal consumed. The gallons pumped per pound of coal would be 188.

This extremely low duty is due to the following:

First. Low duty machinery.

Second. That the pump used for pumping water onto the filter is work- ing against a very low head which materially reduces its duty.

Third. That the plant is not used regularly and a larger proportion of coal is required for banking fires than would be necessary if the plant were in steady use.

The coal used for heating the station is also included and if this could be deducted, the duty would be somewhat increased.

Cost Per Million Gallons - Fuel Alone

Coal, 382 tons at $8.00

$3,056.00

$3056 divided by 143.4 million gallons

$21.31

Labor .

I am informed by you that it is necessary to keep an engineer and fire- man at the station during the time the plant is in operation, and at an ex- pense of $10.50 per day.

Cost of Labor

During the year 1919 the plant in use 288 working days at $10.50 per day equals $3024. $3024 divided by 143.4 million gallons equals $21.08. Cost per million gallons coal and labor alone:

1919 Coal Labor

$21.31 21.08

$42.39

Owing to the low duty type of pumping machinery and high cost of coal and labor the plant is not an economical one to operate, and if this portion of the town supply is to be kept in commission new machinery should be installed.

Considering the fact that the supply from this source is limited I do not consider it wise to install another steam plant and should advise that an electrically driven pump be selected. I have considered two types of pumps, centrifugal and triplex, either of which would be driven by an elec- tric motor. Either type of machinery could be installed in the present station.

In order to pump the required amount of water the machinery should be of the same capacity as that of the present plant.

Centrifugal Machinery

I have estimated on two centrifugal pumps direct connected to electric motors and having a capacity of one and one-half million gallons in 24 hours.

One unit would be located in the basement of the station and used for

129

pumping water from the pond onto the filters. The other would be in the main station and pump from the filter into the distributing system of the town.

Both units would be provided with automatic controlls so that they will start and stop without attendance when the water in the standpipe and filters reaches certain limits.

Cost of pumping per pillion gallons, based upon current at 2 cents per K. W. H .:

Current required per million gallons:

Filter service pump.

Average head including suction, 30 feet,

Combined efficiency pump and motors, 58 per cent,

Current required,

135 K. W. H.

Standpipe service pump.

Average head including friction and suction, 200 feet.

Combined efficiency pump and motor, 63 per cent,

Current required 995 K. W. H.

1130 K. W. H.

at 2 cents equals $22.60

The average cost per million gallons for coal alone during the past two years has been $23.05 or 45 cents per million more than the cost of elec- tricity.

There will be no material reduction in the cost of power alone and the saving will be in labor.

Present Labor

In order to operate the filters both pumps must be in operation at the same time, this requires the use of two boilers and it is necessary to keep an engineer and fireman on duty all of the time.

With electric driven machinery and having as far as possible automatic controls, there is no reason why one man should not be able to look after the entire plant.

I believe the labor item can be reduced at least 50 per cent without im- paring the service or taking any chance whatever. I do not mean to say that the plant will run without care, but it should not be necessary for a man to stay in the station all of the time that the pumps are running.

In the City of Newburyport the water department has been using electric driven pumping machinery for a number of years at their auxiliary station. In this place the chief engineer at the main station goes to the station (which is located about two miles distant) once a day and spends an hour or two looking over the machinery, oiling, cleaning, etc. The sta- tion is then locked up and the machinery left running under 24 hour service.

One unit has been in use about five years and the only labor has been as above stated. Many towns are using electric driven machinery in the same manner with satisfactory results, and I see no reason why the West- wood plant can not be operated in the same way.

When pumping the present amount of water, a yearly saving of at least $1500 should be made in labor alone.

Water Hammer

I am informed by you that there is considerable annoyance caused by water hammer when the present pumps are running, particularly on the high land in the vicinity of the standpipe. I believe this trouble will be overcome to a large extent, if not entirely, by the use of centrifugal pump- ing machinery, the flow from which is nearly uniform.

130

Cost of Installation of Electric Driven Machinery

I have secured approximate estimates for installing electric driven cen- trifugal pumping machinery which estimates are as follows: Filter Service Unit:

1. One and one-half million gallon centrifugal pump direct connected to 15 H. P. motor, together with automatic controls.

Standpipe Service Unit:

1. One and one-half million gallon centrifugal pump, direct connected to 100 H. P. motor, together with automatic controls.

Piping, Foundations, etc.

$7500 2500

$10,000

This estimate is approximate and undoubtedly should you decide to go ahead with the work, by asking for competitive bids a lower price could be obtained.

The interest and depreciation upon the cost of the plant, or 42 per cent for interest and 5} per cent depreciation would amount to $1000 per year, and the annual saving in labor should amount to at least $1500, or a net saving of $500.

Force Main From Pumping Station to the Standpipe

This main is 10 inches in diameter and about 7000 feet in length. It was laid at the time the system was constructed.

Loss in Friction.

The pressure gages in the pumping station show a static pressure, with a full standpipe of 54 pounds and a dynamic pressure of 82 pounds, or a loss due to friction of 28 pounds.

The theoretical loss when pumping at the rate of 1025 gallons per minute would be 21.5 pounds, as against 28 pounds or the actual loss. Considering the length of time that this main has been in use the increased loss due to friction is small.

In order to reduce the head due to friction loss at the pumping station, it would be necessary to lay another main parallel with the present one.

I have estimates on another 10-inch main, the result of which would be as follows:

Cost of Pumping with Electric Power with present Mains: 1045 gallons per min. x 200 head x 8.34

33,000

= 52.5 H. P. by 63%

Combined efficiency = 83.4 H. P .= 62.2 K. W.

62.2 K. W. x 24 hours div. by 1.5 million gallons = 995 K. W. H. per million gallons.

Cost of Pumping with Duplicate 10" Main:

1040 gallons div. by 2 = 520 gallons through each = 15 feet loss in friction. Static Head = 54 lbs. = 125 feet Friction loss = 15 feet

Suction = 10 feet

150 feet 1040 gallons x 150 x 8.34

: 39.3 H. P. = 63% efficiency

33,000

= 62.5 H. P .= 46.6 K. W.

46.6 K. W. x 24 hours div. by 1.5 million gallons = 745 H. W .H. per million gallons.

131

Based upon 150 million gallons per year the cost of current alone would be as follows (not including filter pump) : Present 10" main alone - 150 million x 995 K. W. H. at 2 cents = $2985 With duplicate main

150 duplicate x 745 K. W. H. at 2 cents == 2235

Annual saving in cost of current $750

Cost of New Main

Under present conditions the cost of laying a new 10-inch main parallel with the present main would be about as follows:

7000 feet 10" pipe == 210 tons at $65.00

$13,650.00

Laying 7000 feet at 1.00

7,000.00

Gates and fittings

250.00

$20,900.00

Add 10% for rock excavation and contingencies

2,090.00

$22,990.00

Annual cost of new main:

$22,900 x 6 % (interest and depreciation) =

$1,379.00

With a new 10-inch main the annual saving in current alone when pump- ing 150 million gallons per year would amount to $750, or a little more than one-half of the yearly depreciation and interest upon the cost.

If Buckmaster Pond was of sufficient capacity to furnish the entire sup- ply for the town, I should advise that a new main be installed, but as the quantity is limited to about 600,000 gallons per day (throughout the year) and as there is no possibility of increasing this amount, I do not consider it wise to make any change in the existing main and particularly at present under the extremely high prices.

Cast Iron Siphon and Outlet into Dosing Tank

The inverted siphon that conveys the sewage from a point about 200 feet north of Willow street to the intersection of the 24 inch field line lead- ing to the filters is 16 inches cast iron pipe. The total length is 3864 feet.

The outlet into the 24-inch field line is 4.7 feet lower than the beginning or upper end. The lowest point is where it crosses under the Neponset River. At this point the invert is 14.3 feet below the outlet into the 24- inch main. The capacity under normal conditions is estimated at 1400 gallons per minute, or a little over 2 million gallons per day.

When the system was constructed it was estimated that its capacity would be sufficient to serve the needs of the town for at least 20 years and it was not thought best to provide beyond that time.

Undoubtedly the town has grown at a much more rapid rate than was anticipated, and while the capacity of the siphon is ample for the present flow of sewage alone, at times of heavy rains, when surface water finds its way into the sewers through the openings in the manhole covers through- out the entire system, the flow is increased to an extent sufficient to load the siphon to its full capacity.

In addition to the gravity flow the siphon receives the flow from the pumping section, or that portion of it already provided with sewers. This sewage is collected in a reservoir having a capacity of 130,000 gallons, and is pumped into the siphon at a point about 1000 feet above the lower end, or outlet into the 24-inch main.

The pump has a capacity of 700 gallons per minute and in order to empty

132

the reservoir it must run about 120 minutes. At times of heavy rains when the siphon is loaded to its full capacity, the extra flow due to the discharge from the pumps causes the sewage to back up in the siphon during the pumping period.

Main Sewer or Outlet from the Lower End of the 24-inch Field Line to Dosing Tank

This sewer is 15-inch vitrified pipe and is laid in embankment for the entire distance.

It is 1775 feet in length and has a slope of 1.78 feet per 1000.

The invert at the dosing tank is 3 feet below the flow line, and the sewer works under a head for almost its entire length.

The capacity under normal conditions is 1400 gallons per minute, or practically the same as that of the cast iron siphon.

This section of the sewer is of sufficient capacity for the present flow of sewage alone, but in common with the siphon is overloaded during periods of heavy rains.

At such periods and particularly when the pump is running, the sewage backs up in the manhole located at the head of the 15-inch line about five feet in height and overflows the top.

I was informed by your superintendent that this has occurred a number of times and there is evidence of its recent occurrence, as shown by paper and other floating matter near the two upper manholes in the embank- ment.

This creates a back pressure in the siphon and causes the sewage to back up into the sewers in the low lying sections.

In addition to the trouble caused by the sewage backing up into the sewers, the flow in the siphon is materially reduced due to loss in head. When the sewage stands five feet above the invert in the manhole at the head of the 15-inch main, the available head in the siphon alone is practi- cally nothing and head must be created by backing the sewage up into the main sewers.

I am of the opinion that this section of sewer is largely responsible for the trouble and, in order to provide for the increase in flow due to heavy rains, the present capacity should be increased. By increasing the ca- pacity of the line the back pressure in the siphon will be reduced and the flow materially increased.

Cast Iron Siphon

The sewage from the gravity section enters the siphon at three points, or at the head near Willow Street, at Willow Street and at Dean Street.

The flow is increased by the flow from the pumping section which is pumped into the siphon at the rate of 700 gallons per minute for a period of abour two hours a day.

During the pumping period and at times of heavy rains, the lower end of the siphon is overloaded, due largely to back pressure caused by the 15-inch line.

I am of the opinion that that portion of the siphon extending from the pumping station to the upper end north of Willow Street is of ample size and of sufficient capacity for many years and that the trouble exists in the section between the pumping station and the head of the 24-inch line, and in the 15-inch line to the dosing tank.

In order to provide for the increase in flow, it will be necessary to first, increase the capacity of the 15-inch line, and second, increase the ca- pacity of the siphon from a point just north of the pumping station con- nection to the head of the 24-inch line.

Line to Dosing Tank

This line should be of sufficient capacity to prevent any back pressure

133

in the siphon and I should advise that an 18-inch pipe be laid in the em- bankment and parallel with the present 15-inch pipe, extending from the lower end of the 24-inch line to the dosing tank. This will provide for a flow (in addition to the present line) of 2000 gallons per minute, or a total flow including the present line of 3400 gallons per minute.

Increased Capacity of Siphon

In order to increase the capacity of the siphon, it will be necessary to lay a new pipe connecting with the present siphon at the pumping station and discharging either into the head of the 24-inch field line, or into the head of the line leading to the dosing tank. I have considered three routes:

First: Parallel with the present line from the pumping station to the upper end of the 24-inch.

Second: From the pumping station along the northerly bank of the river a distance of about 700 feet, then across the river and back of the Morrill Ink Works and through the field to the upper end of the line leading to the dosing tank, a total distance of 1700 feet.

Third: From the pumping station across the river and through the yard of the Morrill Ink Works, between the buildings and the N. Y., N. H. R. R. and intersecting Pleasant Street at a point just south of the spur track across the street, and then continuing to the head of the 24-inch sewer.

Of the three routes there is but little choice as far as the capacity is con- cerned.

The line north of the river and through the field to the upper end of the 15-inch sewer has a fall of .8 of a foot more than the other two lines. The line is, however, 700 feet longer and the extra loss due to friction nearly if not quite offsets the gain due to the extra fall.

If the line is laid in Pleasant Street parallel with the present line, it will be necessary to open up about 450 feet of trench through the concrete pavement, or as you suggest, lay it under the sidewalk.

The route back of the Morrill Ink Works would avoid disturbing the con- crete. It would, however, be laid in private property for a distance of about 500 feet, and the length would be 250 feet more than the line laid parallel with the present line. It would also necessitate four angles which are not desirable if they can be avoided.

Of the three routes, I believe the Pleasant Street one, or parallel with the present line, the more desirable, and unless there is some good reason otherwise should advise that it be followed.

Size of Pipe

The new pipe should be of sufficient size to divert at least one-half of the flow. I have considered three sizes, or 16-18 and 20 inch. Of the three I believe the 18 inch should be selected. The carrying capacity of this size will be nearly one-third greater than the capacity of a 16-inch pipe and the difference in cost between a 16-inch and 18-inch line will be practically all in the extra weight of the pipe.

RECOMMENDATIONS

Filters

The water from Buckmaster Pond contains usually a larger quantity of organic matter than is found in a good surface water and is at times very offensive to taste and smell.

A large portion of the bottom of the pond is covered with mud and decomposed organic matter, which in all probability affects the quality of the water. The filters are designed chiefly for the removal of the ob- jectionable taste and odor and in order to furnish filtered water at all

134

times another filter must be constructed; and if Buckmaster Pond is to be used as a part of the permanent supply, I should advise that another filter be built the coming season.

Pumps

The present pumping machinery is of the low duty type and uneconomi- cal to operate, both from the amount and high cost of coal and labor re- quired to operate the station. As now used in connection with the filter, there is but one pumping unit, and should an accident happen, the filter is out of commission until repairs are made. I advise that electric driven centrifugal pumps be installed and used for the regular service and that the present pumps be kept in reserve and used as an auxiliary plant.

Force Main

I should not advise making any change in the present force main leading to the standpipe, as the annual saving in the cost of pumping would not be sufficient to pay the interest and depreciation upon the cost of construc- tion.

Need help finding more records? Try our genealogical records directory which has more than 1 million sources to help you more easily locate the available records.

Norwood annual report 1915-1922, Part 66

Author: Norwood (Mass.) Publication date: 1915 Publisher: The Town Number of Pages: 1954

Author: Norwood (Mass.)
Publication date: 1915
Publisher: The Town
Number of Pages: 1954