The separate system of sewerage: its theory and construction

Front matter

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Preface To The Second Edition

The first edition of this book was exhausted sometime since and numerous calls have been made for another edition. The book has been entirely re-written and much new matter has been added. An effort has been made to facilitate computations by Kutter's formula and tables of the value of n have been added to assist in a proper determination of its value tor sewers.

The question of Sewage Disposal has also received attention.

134945

Digitized by VjOOQIC -

Preface To The First Edition

The subject of the sewerage of towns is attrac5ling much more attention now than formerly. The reason for this is evident. While the country was new and the towns small and sparsely built, the disposal of the liquid wastes and other refuse was left to be provided for by each householder as he might deem best.

Various plans were employed, most of which were objectionable, and, in many cases, no plan at all. But as the towns increase in size and are more compa(5lly built the question of a proper system of Sewerage forces itself upon the attention of the people. Some general system must be adopted for the whole town and the question is, what system ?

The moderate cost of the "Separate System" makes it possible to carry out a system of sewerage in many cases where the expense of the "Combined System" would make the construction of sewers impossible.

One hindrance to the rapid introducflion of the Separate System has been the lack of available information concerning it. Much has been written on the subjecfl, but the necessary information is scattered in numerous pamphlets, reports and papers presented to scientific societies in the United States and in England.

The objecfl of this book is to explain what the Separate System is, what it is designed to do, and to give practical

PREFACE TO THE FIRST EDITION.

directions for designing and construcfking sewers in accordance with that system.

No single design, however complete in all its details, will be best adapted to every case. Each town will present some features peculiar to itself and the general plan must be modified to suit the conditions of each case. All that is here attempted is to give sufficient theory, data and results of experience to guide in properly. designing and construd^ing sewers on the Separate System.

Chapter I

INTRODUCTION. PAGE 1 7.

^eed of Sewerage. — Pollution of Streams. — Pollution of the Sobsoil and Wells, — Typhoid Fever. — Analysis of Well Water. — Effedl of Sewerage. — Systems in Use.

CHAPTER n.

WATER CARRIAGE SYSTEMS. PAGE 37.

The Combined System. — The Separate System. — Subsoil Drainage.

CHAPTER HI.

THE SEPARATE SYSTEM. — PAGE 44.

Roof Water. — Size and Material. — Flushing. — Ventilation. — Special Features. — Adaptability of the Separate System.

CHAPTER IV.

PLANS. — PAGE 56.

Sewage Disposal. — Storm Water. — The Preliminary Survey. — Capacity Required. — Changes of Temperature. — Use of Water Increasing.

CHAPTER V.

QUANTITY OF SEWAGE. — PAGE 63.

The Quantity of Water Required. — Varying Rates of Water Consumption. — Statistics of Water Consumption. — Sewer Gaugings.

CONTENTS.

CHAPTER VI.

LAWS OF FLOW IN SEWERS. PAGE 88.

EffecSl of increasing size. — EffecSl of Hydraulic Mean Radius. — Computation of Discharge and Velocity for any Diameter and any Depth of Flow. — Velocity Required to Prevent Deposit. — EffecSl of Decreasing Quantity of Sewage. — Minimum Velocity. — Graphical Solution. — Comparison of Various Standard Formulae. — Loss of Head on. Curves. CHAPTER Vn.

MATERIAL AND ACCESSORIES. PAGE I23.

Sewer Pipes. — Hand-Holes. — Lamp-Holes. — Fresh Air Inletg. — Man-Holes. — Flush-Tanks. — Y Branches. ^

CHAPTER VHL

SPECIFICATIONS AND CONTRACT. PAGE 1 32.

Letting the Contradl. — Form of Advertisement. — InstrucStions to Contradlors. — Form of Proposal. — Form of Specifications:^ and Contract. — Form of Bond.

CHAPTER IX.

CONSTRUCTION. PAGE I52.

Importance of Record. — Alignment. — Reference Points. — Methods of Work. — Curves. — Transit Notes. — Level Notes; — Profiles. — Working Map. — Note Books. — Construiflion. — Pipe Laying. — Depth. — Grade Line. — Bracing and Sheet Piling. — Inspection of Material. — Location of Y Branches. — Artificial Foundation. — Man-Holes. — Flush-Tanks. — Lamp- Holes. — House-Sewers.

CHAPTER X.

FLUSHING AND VENTILATION PAGE 175.

In the Combined System. — In the Separate System. — Roof Water. — Traps on Main Drain. — Automatic Flush-Tanks. — Field Waring Tank.— Van Vranken Flush-Tank.— The Miller Automatic Tank. — Rhodes Williams Flush-Tank. — The Lightning Automatic Flush-Tank. — Valve Tanks. — Requirements to be met. — Quantity of Water Required. — Rapidity of Discharge.

CONTENTS. XI

CHAPTER XI.

HOUSE DRAINAGE AND PLUMBING. PAGE 203.

House Conne(ftions. — Municipal Control. — Form of Ordinance and Rules for Plumbing. — Form of License. — Form of Bond. — ^Form of Application. — Form of Permit. — House Drains, the Subsoil. — House Sewers. — Grease Traps. — Soil and Waste Pipes. — Traps and Ventilation. — Flushing. — General Features.

CHAPTER Xn.

COST AND ASSESSMENTS. PAGE 225.

Comparative Cost of the Separate and Combined Systems. — Cost of the Separate System. — Examples of Cost from Actual Work. — Data and Cost of Various Systems. — Examples of Cost Computed from Time Book. — Cost of Maintenance. — Sewer Assessments. — Assessments Distributed over a Series of Years. — Installment Table.

CHAPTER Xni.

COMBINED SEWERS. PAGE. 252.

Formulae. — Form of Sewers. — Materials. — Catch Basins. — Man-Holes.

^ CHAPTER XIV.

SEWAGE DISPOSAL. PAGE 256.

Dilution. — Subsidence. — Filtration. — Chemical Processes. CHAPTER XV.

PURIFICATION OF SEWAGE BY APPLICATION TO THE SOIL. PAGE 259.

General Considerations. — The Influence of the Bacteria of Nitrification. — Nitrification. — Absorptive Ppwer of the Soil. — The Fun(ftion of Nitrates in Plant Life. — Experiments of the Massachusetts State Board of Health. — The Influence of Temperature. — Aeration of the Soil. — Effedl of Different Soils. — Self Purification of the Soil. — Quantity and Concentration of Sewage. — Influence of Area. — Sewage Disposal at Pullman.

LIST OF ILLUSTRATIONS.

Page.

Sewerage Map, West Troy, N. Y

Shone Ejedlor 34.

Diagram of Sewer Gaugings at St. Louis 81

Weir for Measuring Flow 84

Observation Opening, etc 91

Diagram Showing Comparative Velocity and Discharge in Circular Sewers of a Given Diameter and Grade for

Various Depths of flow 94

Graphical Sewer Calculations 100

Hand-Hole 125

Details of Fresh Air Inlet 127

Details of Fresh Air Inlet 130

Sketch of ConstrucSlion — Photo. Engraving. i6a

Details of Sheet Piling 162

Details of Man-Hole 164-5

Outlet Chamber 168

Man-Hole — Brick Sewer 169

Iron Cover, Man-Hole and Flush Tank 171

Branches, Curves and House Drains ' 174

Main Traps and Air Inlets 184

Main Traps and Air Inlets 188

Field, Waring Flush-Tank 191

Van Vranken Flush-Tank 195

Miller Flush-Tank 198

Rhodes Williams Flush-Tank 199

The Lightning Automatic Flush-Tank 201

Interior Plumbing 219

Sewage Filter Beds at Pullman — Photo Engraving 279

Broad Irrigation Area at Pullman — Photo Engraving 281

LIST OF TABLES.

Table No. Page.

I. Urban Population of the United States 53

II. Cities Classified According to Population 54

III. Showing Consumption of Water in Twelve Amer-

ican Cities in 1874 and 1884 67

IV. Showing Per Diem Per Capita Consumption of

Water in One Hundred and Seventy-Six American Cities in 1884 68

V. Illustrating Monthly Variation in the Consump-

tion of Water 69

VI. Illustrating Extreme Daily Variations in Con-

sumption of Water 70

VII. Hourly Variations in Water Consumption 71

VIII. Water Consumption at Louisville, Ky 73

IX. Sewer Gaugings at St. Louis 75

X. Comparison of Sewer Gaugings 78

XI. Gaugings of Water Street Main Sewer, Kalamazoo, Mich 83

XII. Illustrating effecSt of Increased Section, the Volume of Discharge Remaining the Same 89

XIII. Showing the Comparative Discharge and Veloc-

ity in Circular Sewers of a Given Diameter and Grade for Various Depths of Flow 93

XIV. Minimum Velocities and Grades in Circular Sewers 99 XV. Showing Maximum Rate of Sewage Flow 102

XVI. Values of «, Kutter's Formula . . 106

XVI LIST OF TABLES.

XVII. Comparing the Discharge in various Cases as

XVIII. Showing increased Frictional Head Required for

Curves in Various Cases 121

XIX. Tests of Sewer Pipe 124

XX. House Drains. 217

XXI. Bids on Sewer fj)nstru(Slion, SchenecSlady, N. Y. 229

XXII. Bids on Sewer Construction, West Troy, N. Y. . 231

XXIII. Bids on Sewer Construction, Dayton, Ohio. ... 234

XXIV. Cost of Thirty-Five Sewerage Systems 236

XXV. Actual Cost of Labor and Material 338

XXVI. Actual Cost of Labor and Material 239

XXVII. Actual Cost of Labor and Material 240

XXVIII. Actual Cost of Labor and Material 240

XXIX. Cost of Sewers in Chicago, 1890 241

XXX. Installment Table 249-

SEPARATE 5Y5TEJV1 OF SEWERAQE.

CHAPTER I.

Introduction

"Sanitary Engineering" has been defined as that branch of engineering which has for its object the improvement of the health of towns and districts, by bringing to them a supply of those things which promote health, and carrying from them those things which are injurious to it.

The three principal requirements for the promotion of health are wholesome food, pure water, and pure air. An abundant and cheap supply of food is best secured by perfecting the means of transportation by land and water. Pure water may be supplied by suitable water works. The air is kept pure by removing from the districts those things which pollute it: that is, by removing all garbage, and by carrying out a proper system of drainage and sewerage.

Although all of these works contribute to the health of a district, yet the subdivision of labor in these times has increased the number of specialties in the engineering profession and has limited the field of the Sanitary Engineer. By common consent the engineer who plans and executes works for improving the means for transportation is called a Civil Engineer; the engineer of a system of water works is called a Hydraulic Engineer: leaving the Sanitary Engineer the task of removing from any locality whatever may be detrimental to health; thus assigning to him the role of scientific scavenger.

Man himself is the principal cause of the defilement of his surroundings. His presence brings pollution to earth, air and water. Nature provides a remedy which is efficient only to a limited extent. Refuse from the animal kingdom is food for the vegetable kingdom. But when human beings congregate in masses nature can no longer meet the demands.

In country districts, where the population is sparse, the disposal of excrementitious and refuse matter is easily managed by each householder in his own way. And even if that way be unadvisable the only sufferers are himself and those of his own household, and no one else will care to interfere. The methods usually there adopted, however, become very objectionable wherever the people congregate in large numbers. The conditions of living become changed. The sanitary condition of the immediate surroundings of each individual concerns not only himself, but the whole community in which he lives; and what was before a personal matter now becomes a question of public policy.

In all densely populated areas, as in large villages and cities, the disposal of the solid and liquid refuse becomes a serious problem. The Mosaic regulations (Deut. xxiii, 12-13) can not be enforced, and to store the filth of a city within the city is simply to invite disease and death.

The use of the pits, dug in the earth, as receptacles for refuse, is in every way objedlionable. The soil becomes polluted with sewage, and the air is filled with the noxious gases arising from the sewage soaked earth, and from the putrefying masses in vaults and cess-pools. The decomposition of so much refuse in such close proximity to the dwellings is detrimental to health in two ways. It uses up the oxygen from the air, and loads it with pestilential gases. If cess-pools are used at all, they should be water tight. This necessitates the constantly recurring trouble of carrying away the contents when they fill up, and only partly removes the difficulty.

Need of Sewerage — An examination into the sanitary condition of a majority of our older cities and villages will show

Chap. I. Introduction. I9

the great need of some kind of sewerage. Many of them have never taken any measures to rid themselves of the necessary accumulations of filth, incident to a considerable population. For generation after generation the refuse which should have been removed far from the dwellings, has been flung upon the surface of the ground, or into cess-pools, where the putrefying mass poisons the air, and appeals in more ways than one for a remedy. '*The offense is rank." On one of the principal streets in one of our oldest cities it became necessary to remove several small houses to erect a large building. The interior of the block was thus exposed to view, and it simply made apparent the state of affairs in nearly every block in the city. Within the space of 150 feet long by 50 feet wide, there were four wells and seven vaults and cess-pools. It needs no chemical analysis to determine the. impurity of water obtained under such circumstances, nor a very vivid imagination to conceive the foulness of the atmosphere in that locality.

The earth upon which many of our cities stand is literally saturated with sewage. The vile odors which are exhaled from the polluted soil, and from the sinks of rottenness and putrefaction which it contains, contaminate the air in the streets, and are a constant reminder of the need of an efficient remedy. There they stand, reeking in the accumulated filth of past generations, never for a day free from malaria, and zymotic diseases; and yet the remedy is easily applied and the cost of it within the reach of the poorest hamlet.

Pollution of Streams. — A small water course running through a city without sewers is sure to become a nuisance. Every conceivable variety of filth and refuse will be thrown into it, and it will soon be simply an open sewer. In dry weather, when the flow of water is at its minimum, the bed of the stream will become an elongated, open cess-pool of the worst variety. The channel is sometimes cleared by throwing the accumulations of filth upon the banks: that is, the filth is spread over a larger surface instead of being removed. Periodical cleanings of the bed and banks of the stream will only mitigate the nuisance temporarily. The cure /must reach the cause of the evil if it is to be radical and entire. The sewage must be provided for in proper channels of its own, and only the storm water be allowed to run into the open water courses.

The following extradls are taken from a report of the State Board of Health of New York. The name of the city referred to is omitted, but the name of any unsewered city or village might be filled into the blank spaces and the report would give the actual sanitary condition in a majority of cases:

' 'Dr. Carroll's full report on the prevalence of filth and malarial diseases -, and the causes thereof, is well worthy a careful reading by every citizen of •

' 'The record is both sad and alarming. Sad, because it shows that at least one-fifth of the deaths in your city during the past year were clearly preventable by ordinary municipal provision for cleanliness; alarming, because the already abnormal death rate from filth poisoning must, from the very nature of the cause, steadily increase. affords another of the many lamentable illustrations of the apparently ineradicable popular delusions that natural water courses are the proper receptacles for sewage and house refuse of all kinds. * * It appears from the report that the number of fatal cases from diphtheria, typhoid fever, diarrhoea and scarlet fever is, at least, three times as great as it should be under normal sanitary conditions. These diseases are known to be intensified, if not dire^ly caused, by filth poisoning. The prevalence of malarial diseases is also reported. » * * There seems to be no doubt that

there is a large amount of malarial trouble in . This disease is usually

associated with surface or sub-soil saturation, occurring either immediately around dwellings or within such a distance that miasmatic emanations may be carried by the winds over an inhabited locality. There appear therefore, to be at least two prominent classes of more or less preventable diseases occurring in

, one of them dependent upon conditions of filth and the other upon

undrained or saturated lands. The nature of these two classes leads to the

conclusion, that filth is accumulating within the city of in such a way,

and in such places, as to effedt the public health, and that there are saturated tradls which produce malarial diseases.

' 'The first and most important measure to stop the present death rate from

filth diseases in is to provide proper means of carrying away the organic

filth of the city. The use of open brook channels as sewers should be absolutely prohibited. They should be reserved for the drainage of surface water only. Such a prohibition can hardly be made effedlual until some means are

CHAP. I. INTRODUCTION. 21

provided for carrying the sewage away from the city. For this purpose a system of sewers is strongly advised, and little relief can be expedled from the present unwholesome condition of the city until sewers have been built. * * "

Pollution of the Subsoil and of Wells. — The ordinary cess-pools are especially objetftionable where wells are used as a sourpe of water supply. A well is simply a hole dug in the ground, into which the water, which has sunk into the earth, may drain. The quality of the water will depend upon the condition of the soil through which it passes. In cities without sewerage, cess-pools by hundreds are formed in the earth, into which all manner of filth is thrown. Into this same soil wells are dug, and the drippings from the cess-pools are caught and drank, and the seeds of disease are sown broadcast in the community. One often hears it said that water which passes through the earth is filtered and purified. But it must not be forgotten that while the earth adls as a sieve, and removes the suspended impurities the oxydation and nitrifacStion of organic matter depends upon circumstances which are not likely to be favorable very far beneath the surface of the ground. Whatever is in solution remains, to a large extent, in the water.

The Swiss village of Lausen, near Basle, is supplied with water from a spring, situated at the foot of a mountainous ridge, called the Stockhalden. In this village, where there had not been a single case of fever in many years, an epidemic of typhoid fever broke out, which struck down seventeen per cent, of the whole population. The cases of fever were pretty evenly distributed among the families in the village, with the exception of six. As the six families which escaped did not use water from the spring, suspicions were aroused concerning the water and investigations were made. It had previously been noticed that when the meadows in the FurlerthaJ — a little valley on the other side of the Stockhalden ridge — were irrigated, the volume of water in the spring was increased; and by the sinking of the soil in one of the meadows in the Furlerthal, a vein of water was discovered, which, it was supposed, led to the spring in Lausen. It was found, upon investigation, that a peasant living in the

Furlerthal had returned home from a distant city, sick with fever, and that the brook in which his clothes had been washed and into which the slops from the house had been thrown, had been used to irrigate the meadows. This water thus spread out over the fields and then filtered through the ridge, a distance of a mile, still carried the germs of disease in it, and brought death to the unsuspecSling inhabitants of Lausen.

To prove, conclusively, that the spring was supplied from the Furlerthal, and to determine whether the water passed through an open vein or was filtered through porous material, the following experiments were made: Several hundred weight of salt was dissolved and poured into the hole in the Furlerthal, where the vein was discovered. In a few hours the water of the spring became very salt, and the connection between the water in the Furlerthal and the spring at Lausen was established beyond a doubt.

They now mixed two and a hall tons of flour in water and poured it into the hole, but no trace of the flour could be found in the spring; proving that the water was so thoroughly filtered as to remove the minutest particles of the flour, and yet it still retained its infedlive properties.

Clearness is no proof of purity in water. The water of the Saratoga Springs, although thoroughly impregnated with various minerals, are as clear as ordinary spring water, and in a glass of water as clear as crystal there may be poison enough to kill a whole family; not only by the comparatively slow and uncertain process of fever, but surely and immediately. Deleterious gases may indeed add a sparkle to well water, and the peculiar flavor so highly prized in some wells may be borrowed from a neighboring cess-poo] .

Dr. Victor C. Vaughn, Professor of Physiological and Pathological chemistry in Michigan University, states in a report to the State Board of Health, that a series of experiments which he has conducSled confirms the germ theory in cases of typhoid fever. The fever was produced in a cat by inoculation and the

CHAP. I. INTRODUCTION. 23

cat showed all the symptoms of the disease. In connection with this Dr. Vaughn states:

* ' Last August there was an epidemic of typhoid fever in the village of Iron Mountain, a place in Northern Michigan of about 4, 000 inhabitants. Part of the town was supplied with water from a mountain spring, and part from private wells from six to twenty feet deep. It was noticed that all those who used the spring water escaped the disease, while those who depended upon the shallow wells were stricken down. In all there were many hundred cases and about forty deaths. I secured some of the water from these shallow wells and with it experimented upon a number of cats, finally obtaining the result which I announced to the Board of Health. "

If, as Professor Vaughn states, these city wells contain fever germs enough to kill a cat, with its traditional nine lives, what chance is there for an ordinary human being with only one?

The following are the results of a very general examination of the water in wells in one of the most beautiful and well kept smaller cities in the state of New York. The natural drainage facilities of the city are excellent. There are no sewers worthy the name, however.

The results are particularly interesting, not only as showing the marked subsurface pollution within a comparatively few years, but also as showing the increased mortality directly resulting therefrom.

' ' I have made some chemical tests of water from nearly one hundred wells to determine, if possible, the extent of the pollution of the drinking water commonly used, and have made out a table which is given below of the results of these tests. The amount of chlorine which a sample of water may contain and not be regarded as unsatisfadlory is usually assumed as 3.5 grains per Imperial gallon. I have drawn a line at this point across the list of wells below, and another at 7.0 grains per gallon, which last may, at least, be called the danger line if not the death line.

In the table with the analyses of the well water I have placed those of some other waters for comparison. No. 77 was urine diluted with 49 parts of pure water, Nos. 85 and 88 are from wells so situated as to drain large barnyards. No. 93 is from the outlet of the sewer which last summer was turned across Main St. and carried down Mill St., joining the Bacon Street sewer. I have also marked those wells used by families where there have been cases of fever and (generally fatal) cases of diphtheria with an "F" and a "D,. respedlively.

THE SEPARATE SYSTEM OF SEWERAGE.

I

3 4 5 6

7 8

II

. Academy Filter . . . . Thayer Spring . . .

. Rain

.Hazelton Spring..

.Country Well

.Country Well

.Lincoln Avenue. .

. Lincoln

.South (i mile out).

.Well in Pasture. .

. Sewer, Lincoln . . . .Spring in Pasture.

.Summit

.St. Marks

.Church

.Main

. Maple

1 ^

2.15 2.15

33 Pond in Village

Average of 9 Rochester | Sewers (Dr. Lattimore) f

3-65 365

3.78

•C § o uS,

^ (0

I S -g a

So J3

SS W U

41 Church 4. 35

49 Pond in Village 5.00

50 Church 5.00

58 Church 6.25

62 Sewer, East Main 6.55

67 St. Marks 7.60

CHAP. I.

INTRODUCTION.

XL

a

U 5 -a

S a

0) S a; a MO.

w

85 Barn Yard Well 11.75

86 Dish Water 11.90

77 Urine in 49 pts. water. . 9.65

The following table shows of the water supplied to Schenedlady, Troy and Albany. The Nitrites were reduced to nitrates and both appear under that heading. Ammonium salts are represented by organic nitrogen. The analysis was carried on under the supervision of Prof. Perkins. The numbers represent parts per 100,000 by weight.

.. Barn Yard Well 1275

. . .Sewer, Mill St 17. 30

Average 78 wells 6. 56

the results of the analysis

91, m^ixsrsi -5

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CHAP. 1. INTRODUCTION. 27

Let US now look at these results and see what they indicate. The total hardness of the water supplied to the three cities is about the same, the difference being no more than would exist in the same water on different days. In permanent hardness the Troy water is much better than that of Schenedtady. The nitrates indicate the sewagp contamination perfectly, increasing as we go down stream from Schenecflady to Albany. Above Schenedtady there is very little sewage flowing into the Mohawk, till we reach Utica, eighty miles above, that being the only place on the river with' a system of sewers. The river itself passes over many rifts and shallows between the places, affording every opportunity for oxydation of the organic matter. At Troy the river has received the sewage of Cohoes, Waterford, Lansingburgh, etc., and at Albany that of Troy and West Troy in addition, and nitrates accordingly increase. The Hudson river water at Albany has been condemned by the Albany Water Commissioner as unfit for use, and a new source of supply has been recommended.

Samples 5 and 6 were from the same well — No. 5 taken just before it was cleaned. No. 6 about six weeks after. There is a vault a short distance from the well, with which it is evidently in diredl communication, the chlorine being more in the second analysis than in the first. No. 7 was furnished by a physician of Schenedlady who was called to prescribe for a man sick with typhoid fever. He suspected that the cause lay in the water, though the man affirmed that it was the best water in the city. The analysis shows, besides ammonia, organic nitrogen, and nitrates in large quantities, an amount of chlorine nearly three times as great as that in common sewage.

In No. 8 the nitrates and chlorine were very high, especially the former. The well is only eighteen feet from a vault.

No. 10 was sent by a physician of Albany. He writes as follows concerning it:

' 'I send you a specimen of well water, which I think has caused three cases of severe illness, two of which were fatal. I was called some months after these cases to see a patient who had a high fever, (temp. 105-5, pulse 140,) with