Sewerage and Sewage Treatment

INDEX

Harold E. Babbitt

blic@vhost@g@html@files@61773@61773-h@61773-h-29.htm.html#Page_311" class="pginternal">311–315

invert construction, 311, 312

sewer construction, 311–315

arch centers, 313
invert, 311–312
organization, 314, 315
progress, 314
row lock bond, 312

specifications, 188, 189

sewers, life of, 351

Bricks for sewers, 316

British Royal Commission on Sewage Disposal, 4

Broad irrigation. See under Irrigation.

Bucket excavators, 246, 255, 256

Building material, weight of, 201

Burkli-Ziegler formula, 47, 425

Butyrine, 366

Cableway excavators, 246, 250–252

Cage screen, 384, 385

Caisson excavation, 285, 286

Calcium carbide, explosive, 347

Calumet pumping station, 128, 142

Cameron septic patent, 411

Capacity of sewers, diagrams, 57–60

Capital, private invested in sewers, 17

Capitalization, method of financing, 157–160

Caps, blasting. See blasting.

Carbohydrate, 366, 367

Carbon, analysis for, 356

dioxide, 366, 367

Carson Trench machine, 250, 251

Cast-iron pipe, 122, 164, 190, 191

joints, 164
quality, 101, 102, 190

Castings, iron, 101, 102

Catch-basins, 99, 107–108, 217

cleaning, 343, 344
inspection, 337

Catenary sewer section, 69

Cellars, depth of, 88

Cellulose, 367

Cement. See also Concrete,

pipe, specifications, manufacture and sizes, 171–179
bond, 213, 222
content, 213, 230, 231
cost-plus, 212, 213
disputes, 220
divisions of, 213
drawings, 213
engineer as an arbitrator, 220
the instrument, 230, 231
interpretation of, 220, 234, 235
lump sum, 212
nature of, 211, 212
sample, 230, 231
time allowed, 222
types, 212, 213
unit-price, 213

Contractor, absence of, 222

bond, 232
claims against, 228
duties, 221
liability, 224
relations with other contractors, 228, 229

Contractor’s powder, 294

Control devices, automatic, for sewers, 117–121

- for filters, 500–512
inspection of, 336, 337

Copper sulphate, disinfectant, 490

Copperas, precipitant, 406–408

Cordeau Bickford, 298, 303

Corrugated iron pipe, 165

Cost. See under item wanted.

Cost, annual. Method of financing, 157–160

capitalized. Method of financing, 157–160
classification of, 235–238
comparisons of. Methods for
making, 157–160
collection of data, 10–14, 235–238
estimate. Method of making, 10–14
overhead, 237, 238

Couplings, flexible for shafts, 138

Covers, Imhoff tanks, 424

septic tanks, 415
trickling filters, 451

Crops on sewage farms, 463, 464

Cunette, 67, 70

Cut, depth of excavation, 88, 92

Cycle, contact bed, 436

life and death, , 367, 374, 375, 410
Freezing, catch-basins, 108
- concrete, 186, 187
- dynamite, 301, 302
Fresh sewage, characteristics, 352–354
Friction losses. See Head losses.
- flow in pipe, 51, 52
Fuel, consumption by prime movers, 153
- costs, 153
- heat value, 150
Fungus growth in sewers, 333
Fuses. See blasting fuses.
Ganguillet and Kutter’s formula, 52–65
Gas, chamber in Imhoff tank. See Scum chamber.
- engines, 152–154
- illuminating, explosive, 347
- sewer, 335, 336
Gasoline, explosive, 108, 109, 335, 346, 347
- engines, 152–154
- and oil separator, 109
- odors, significance, 335, 353
Gearing, reduction for turbines, 140, 146
Gelatine dynamite, 296
Glycerol, 366
Gothic section, 67
Governmental control, stream pollution, 380, 381
Grade, of sewers. See also Slope.
- how given, 281–284
- selection of, 90
- stakes, 221, 281–283
Gravel, specifications, 172
Grease, in sewers, 99, 108, 333, 345
- cutter, 340
- ordinance concerning, 345
- traps, 99, 108
Gregory’s imperviousness formulas, 44, 46
Grit, clogs sewers, 333
- chambers, 127, 397–401
  - description, 395, 398
  - design, 397, 398
  - dimensions, 397, 398
  - existing, 398–400
  - outlet arrangements, 196
  - sulphur and sand, 309
  - types, for pipe, 307
  - working, in concrete, 319
- Junctions, 99
- Kuichling, run-off rules, 46, 47, 49
  - storm intensity formulas, 50
- Kutter’s formula, 52–65
- Labor, day vs. contract, 211
  - costs on concrete sewer, 328, 329
- Labyrinth packing rings, 136, 137
- Lagging, tunnel frames, 287
  - for forms, 322
- Lagooning sludge, 495–497
- Laitance, 186, 188
- Lakes, self-purification of, 376
- LampÉ’s formula, 54
- Lampholes, 99, 104
- Lateral sewer, defined, 7
- Lawrence Experiment Station, 4
- Leaping weir, 118–121, 337
- Legal requirements, construction, 224
  - dilution, 380, 381
  - in design, 9
- Liernur system, 5
- Life, organic in sewage, 363, 364
  - of sewers, 348–351
- Lime as a precipitant, 405–408
  - with electricity, 488, 489
  - with iron, 406, 407
- Line and grade, 281–284
  - how given, 281–283
- Liquefaction of sludge, 411–413, 496, 497
- Liquid chlorine. See also Chlorine, 491
- Liquidated damages, 222
- Loads on, pipe, 198–202
  - Marston’s method, 198–202
  - trench, 199–202
- Lock bar pipe, 197
- Lock-joint pipe, 177
- Long loads, 201
- Machine excavation. See Excavation.
- Macroscopic organisms, 363, 368
- Main sewer, defined, 7
- Maintenance of sewers, Chap. XII, 332–351
  - catch-basin cleaning, 343, 344
  - cleaning sewers, 337
    - inspection of, 337
  - Reinforced concrete sewer design, 209, 210
  - Reinforcing steel, specifications, 191
    - placing, 326, 327
  - Reinsch Wurl screen, 384
  - Relative stability numbers, 359
  - Relief sewer, defined, 7
  - Repairs to sewers, 337
  - Report, engineer’s preliminary, 10
  - Reservoir, collecting capacity, 129, 130
  - Residences, septic tanks for, 416, 417
  - Residential districts, characteristics, 32–37
  - Residue on evaporation, 356, 357
  - Rideal’s dilution formula, 379
  - Ring, design. Chap. IX, 194–210
    - stresses in circular, 202–204
  - River pollution, legal features, 380, 381
  - Rivers, self-purification of, 373–376
  - Riveted joints, properties, 196
  - Rock, blasting, 268, 290, 291
    - definition, 263
    - drill, data on, 266, 267
    - drilling. See also Drilling.
      - by hand, 264
      - by power, 264–268
      - rates, 267
    - excavation. See also Excavation.
      - payment for, 230
    - measurement of, in place, 235
    - tunnels, 290, 291
  - Rods, sewer, 338
  - Roman ordinance relative to sewers, 2
  - Roofs. See Covers.
  - Root cutters, 340
  - Roots, 333, 340
  - Row lock bond for bricks, 312
  - Running water, self-purification, 373–376
  - Run-off, computations, 17, 40, 46–50, 94–98
  - Safeguards during construction, 221, 241
  - Salt water, dilution in, 376, 377
  - Sand, effective size, 456
    - uniformity coefficient, 456
    - filters, 452–459
      - action in, 431, 432, 452–454
      - control, 36, 37, 85
    - fresh, 352–354
    - gas, 335, 336, 353
    - industrial, defined, 7, 352
    - life in, 363–365, 368
    - odor, 353
    - physical, analyses, 352–354
      - characteristics, 352–354
    - quality variations, 368–370
    - quantity. Chap. III, 24–50, and 84, 87
      - and population, 31, 32
      - of sanitary, 24–40
      - variations, 33–38
    - sanitary, defined, 7, 352
    - septic, 353, 365–368, 371, 410, 411, 496, 497
    - stability, 359, 360
    - stale, 353
    - storm, defined, 7, 352
    - strong, 355
    - temperature, 353
    - turbidity, 353
    - treatment processes, 370, 371
      - A. B. C., 4
      - activated sludge, Chap. XVIII, 465–479
      - biological, 371
      - chemical, 371
      - contact bed, 432–437, 506
      - costs, 459
      - dilution. Chap. XIV, 372–382
      - disinfection, 489–493
      - electrolytic, 487–489
      - filtration, 431–459
      - increase of, 3
      - irrigation, 431, 459–464
      - mechanical, 471
      - Miles acid process, 482–487
      - purpose of, 6, 370
      - rÉsumÉ, 6, 370, 371
      - sand filter, 452–458
      - screening, 383–391
      - sedimentation, 391–409, 411
      - septicization. Chap. XVI, 410–430
      - trickling filters, 192, 193
        
        design, 197, 198
      - working strength of, 277
    - Work, extra, 227
      - preliminary to design, 9
      - Sunday, night, and holiday, 221
    - Workmen, competent, 227
      - dishonesty, 233, 234
    1. Frontinus and the Water Supply of Rome, p. 81, by Clemens Herschel.

2. Estimated by G. W. Fuller, Trans. Am. Society of Civil Engineers, Vol. 44, 1905, p. 148. The total population connected with sewerage systems was assumed to be the total population in the United States in cities over 4000 in population.

3. Estimated by Metcalf and Eddy, American Sewerage Practice, Vol. III, p. 240.

4. Computed from report of the United States Census, 1920, on the same basis as Fuller’s estimate for 1905.

5. Cosgrove, History of Sanitation.

6. Sedgwick: Sanitary Science and Public Health.

7. No detrimental effect on the public health was noted as a result of this condition however. It has never been conclusively proven that such nuisances are detrimental to the public health.

8. Moore and Silcock, Sanitary Engineering, p. 67, 1909.

9. Similar to the definition proposed by the Am. Public Health Assn.

10. Definition recommended by Am. Public Health Assn.

11. Ibid.

12. Ibid.

13. Eng. News, Vol. 76, 1916, p. 781. See also Eng. News-Record, Vol. 85, 1920, pp. 22, 1175.

14. For a more extensive treatment of the subject see Principles and Methods of Municipal Administration by W. B. Munro, 1916.

15. Eng. Record, Vol. 74, 1916, p. 263.

16. Professional paper No. 46, United States Geological Survey, 1906, p. 97.

17. United States Geological Survey, Water Supply paper No. 257, 1911.

18. From Eng. Cont., Vol. 41, 1914, p. 698.

19. Max. represents only the average maximum, not the greatest maximum.

20. Eng. News-Record, Vol. 80, page 1233, 1918.

21. Infiltration of Ground Water into Sewers. Transactions of the American Society of Civil Engineers, Vol. 76, 1913, p. 1909.

22. A comprehensive discussion of rainfall formulas will be found in Vol. 54 of the Transactions Am. Society of Civil Engineers, 1905.

23. Formula devised by H. E. Babbitt from Allen’s 25–year curve.

24. See Note under Table 14.

25. Sewerage by A. P. Folwell.

26. From an article by E. Kuichling in Transactions American Society of Civil Engineers, Vol. 65, 1909, p. 399.

27. Trans. Am. Society Civil Engineers, Vol. 58, 1907, p. 483.

28. Trans. American Society of Civil Engineers, Vol. 58, 1907, p. 498.

29. Ibid.

30. The principles governing the run-off from large areas are explained in Elements of Hydrology, by A. F. Meyer, 1917.

31. Transactions of the American Society of Civil Engineers, Vol. 51, 1903, p. 11.

32. Municipal and County Engineering, Vol. 58. 1920, p. 164.

33. Industrial waste Treated as ground water.

34. For diagrams for the Solution of the Rational Method, see Eng. News-Record, Vol. 83, 1919, p. 868 and Vol. 85, 1920, p. 151.

35. Municipal and County Engineering, October, 1909.

36. “Cleaning and Flushing Sewers.” Journal of the Association of Engineering Societies, Vol. 33, 1904, p. 212.

37. Notes on the Design and Principles of Sewage Siphons, Eng. News-Record, Vol. 85, 1920, p. 1041.

38. From A. E. Phillips, Trans. Am. Society of Municipal Improvements, 1898, p. 70.

39. Trans. Am. Society of Civil Engineers, Vol. 15, 1886.

40. True Siphon at East Providence, Eng. News-Record, Vol. 85, 1920, p. 862.

41. “The Effect of Mouthpieces on The Flow of Water Through a Submerged Short Pipe,” by F. B. Seely. Bulletin No. 96, 1917, of the Eng’g. Experiment Station of the University of Illinois.

42. Trans. Am. Society of Civil Engineers, Vol. 49, 1902.

43. Described by W. L. Stevenson before the Boston Society of Civil Engineers in 1916.

44. Multiple Outlet for Calumet Intercepting Sewer, by S. T. Smetters, Eng. News-Record, Vol. 83, 1919, p. 728.

45. “Direct Acting Steam Pumps,” by F. R. Nickel, 1915.

46. From Heat Engines, by Allen and Bursley.

47. “The Economy Resulting from the Use of Variable Speed Induction Motors for Driving Centrifugal Pumps” by M. L. Enger and W. J. Putnam. Journal Am. Water Works Ass’n., 1920, Vol. 7, p. 536.

48. C. A. Hague in Trans. Am. Society of Civil Engineers, Vol. 74, 1911, p. 20.

49. Includes screen chamber, collecting reservoir, and building.

50. Computed on the assumption that the pumps may be operated at 50 per cent overload for short periods, the rated capacity being equal to the loads given in Table 33.

51. For description of type see note under Table 35.

52. Proceedings Illinois Society of Engineers, 1916, page 81.

53. Municipal Engineers’ Journal for April, 1918.

54. Workability involves ease in placing and smoothness of working.

55. Johnson’s Materials of Construction, 5th Edition, 1918, p. 432.

56. Trans. Am. Society of Civil Engineers, Vol. 59, 1907, p. 146.

57. L. N. Edwards, Trans. Am. Society Testing Materials, 1918, and R. B. Young, Eng. News-Record, Vol. 82, 1919, p. 33.

58. Bulletin No. 1, Structural Materials Research Laboratory, Lewis Institute, Chicago, Illinois.

59. Proportioning Concrete by Voids in the Mortar, A. N. Talbot, read before Am. Society Testing Materials, June 22, 1921. Abstract in Eng. News-Record, Vol. 87, 1921, p. 147.

60. Trans. Am. Society of Civil Engineers, Vol. 81, 1917, p. 1122.

61. See also Tentative Specifications for Concrete and Reinforced Concrete submitted by the Joint Committee to its Constituent Organizations, June 4, 1921.

62. Journal Illinois Society of Engineers for 1916, p. 75.

63. See A. S. T. M. Standards for 1918, p. 148.

64. Trans. Am. Society Civil Engrs., Vol. 82, 1918, p. 459.

65. See Trans. Am. Society Civil Eng., Vol. 82, 1918, p. 482.

66. See Trans. Am. Society Civil Engr., Vol. 41, 1899, p. 76, and Vol. 82, 1918, p. 433, Eng. News, Vol. 74, 1915, p. 400, and Vol. 75, 1916, p. 911.

67. Trans. Am. Soc. Civil Engrs., Vol. 82, 1918, p. 433.

68. Bulletin No. 31 of the Engineering Experiment Station of the Iowa State College of Agriculture.

69. From bulletin No. 31, Engineering Experiment Station, Iowa State College of Agriculture.

70. From Bulletin No. 31, Engineering Experiment Station, Iowa State College of Agriculture.

71. From Bulletin No. 31, Engineering Experiment Station, Iowa State College of Agriculture.

72. From Vouissoir Arches by Cain.

73. Baker’s Masonry, 10th Edition, p. 676.

74. Business Law for Engineers, C. Frank Allen, McGraw-Hill, 1917; Engineering Contracts and Specifications, J. B. Johnson, McGraw-Hill, 1904; Contracts in Engineering, J. I. Tucker, McGraw-Hill, 1910; The Law Affecting Engineers, W. V. Ball, Archibald Constable, 1909; Law and Business of Engineering and Contracting, C. E. Fowler, McGraw-Hill, 1909; The Economics of Contracting, D. J. Hauer, E. H. Baumgartner, 1915; The Elements of Specification Writing, R. S. Kirby, John Wiley & Son, 1913; Contracts, Specifications and Engineering Relations, D. W. Mead, McGraw-Hill, 1916; Engineering and Architectural Jurisprudence, J. C. Wait, John Wiley, 1912.

75. See article by E. W. Bush in Eng. News-Record, Vol. 85, 1920, p. 122.

76. An unbalanced proposal is one in which the bids on some of the items are obviously low and on other items are obviously or suspiciously high. The purpose of submitting unbalanced bids is to keep secret the true or supposed cost of the work to the contractor or to obtain more money by bidding high on those items which are believed to have been underestimated by the Engineer. A low bid is made on other items in order to keep down the total amount of the bid.

77. Taken mainly from specifications of the Sanitary District of Chicago and the Baltimore Sewerage Commission, with miscellaneous selections from other sources.

78. Restrictions are placed on work done outside of ordinary working hours in order that the Contractor may not perform work in the absence of an engineer or inspector.

79. Cost Keeping and Management, by Gillette and Dana. Practical Cost Keeping for Contractors, by F. R. Walker. Cost Keeping in Sewer Work, by K. O. Guthrie in Eng. Contracting, Vol. 28, p. 238, 1905. Sewer Construction Records at Scarsdale, Eng. News-Record, Vol. 83, p. 111, 1919.

80. See Planning and Progress on a Big Construction Job, by Chas. Penrose, Eng. News-Record, Vol. 84, 1920, pp. 554 and 627.

81. See also “Ownership and Operation of Trench Excavators by the Water Department of Baltimore,” by V. B. Seims, presented before Am. Water Works Association, June 9, 1921.

82. Eng. and Contracting, Vol. 48, 1917, p. 492.

83. Earth Excavation by A. B. McDaniel.

84. Courtesy, Sanitary District of Chicago.

85. See article by J. R. Gow, Journal New England Waterworks Ass’n, Sept., 1920, also Public Works, Vol. 50, p. 98.

86. Diameter of diaphragm.

87. Gallons per minute.

88. Eng. News, Vol. 75, 1916 p. 1050.

89. Mun. Engineering, Vol. 53, p. 6.

90. For types of drill bits see article by T. H. Proske, Mining and Scientific Press, March 5, 1910.

91. These intermediate holes are seldom more than 3 feet apart.

92. Earth Pressures, Old Theories and New Test Results, Eng. News-Record, Vol. 85, 1920, p. 632.

93. Trans. Am. Society Civil Eng’rs, Vol. 60, 1908.

94. Adopted by the Am. Ry. and Maintenance of Way Ass’n in 1907.

95. Tunneling Machines Successful on Detroit Sewers, Eng. News-Record, Vol. 84, 1920, p. 329.

96. Rules on Compressed-Air Work of N. Y. State Industrial Commission, Eng. News-Record, Vol. 85, 1920, p. 1225.

97. Taken mainly from the Engineer Field Manual of the U. S. Army; Safety Factors in the Use of Explosives by W. O. Snelling, Technical Paper No. 18, U. S. Bureau of Mines; and an article in Eng’g and Contracting, Vol. 52, 1919, p. 585.

98. See paper by C. T. Hall before Am. Inst. Chemical Engineers.

99. Per cubic yard of material displaced.

100. Eng. News, Vol. 75, 1916, p. 592.

101. Pressure of Concrete on Forms Measured in Tests, by E. B. Smith, before Am. Concrete Institute, Feb. 15, 1920. Abstracted in Eng. News-Record, Vol. 84, 1920, p. 665.

102. See, also, Concrete Form Design, by E. F. Rockwood, Eng. and Contracting, Vol. 55, 1921, p. 528.

103. Includes 6 cents per foot for excavation. Labor for this was 58 per cent of the total labor cost.

104. Cement at $1.25 per barrel.

105. Mun. Journal, Vol. 36, 1914, p. 736.

106. Mun. Journal, Vol. 39, 1915, p. 911.

107. Formerly the Municipal Journal.

108. See Eng. Record, Vol. 75, 1917, p. 463.

109. Eng. Record, Vol. 73, 1916, p. 141, and Eng. News-Record, Vol. 79, 1917, p. 1019.

110. Eng. Record, Vol. 72, 1915, p. 690.

111. Eng. Record, Vol. 71, 1915, p. 256.

112. Eng. and Contr., Vol. 41, 1914, p. 250.

113. H. J. Kellogg in Journal Connecticut Society of Civil Engineers, 1914, and Technical Paper 117, U. S. Bureau of Mines.

114. Eng. News, Vol. 70, 1913, p. 1157.

115. Technical Paper No. 117, U. S. Bureau of Mines.

116. Eng. News, Vol. 71, 1914, p. 84.

117. Eng. News, Vol. 71, 1914, p. 82.

118. Similar to definition proposed by the Am. Public Health Ass’n.

119. Economic Values in Sewage and Sewage Sludge, by Raymond Wells, Proceedings Am. Society Municipal Improvements, Nov. 12, 1919. Eng. News-Record, Vol. 83, 1919, p. 948.

120. Sample boiled for five minutes.

121. Sample immersed in boiling water for 30 minutes.

122. Four months.

123. One week in March, 1914.

124. R represents any chemical element such as K, Na, etc.

125. Standard Methods of Water Analysis, American Public Health Association, 1920.

126. Routine tests are ordinarily incubated for this period only, and if not decolorized in this time are recorded as stable.

127. Determination of the Biochemical Oxygen Demand of Sewage and Industrial Wastes, by E. J. Theriault, Report of the U. S. Public Health Service, Vol. 35, May 7, 1920, No. 19, p. 1087.

128. Standard Methods of Water Analysis, American Public Health Association, 1920.

129. Jordan, General Bacteriology, 1909, p. 91.

130. Ibid.

131. Reprinted in Vol. III of Contributions from the Sanitary Research Laboratory of Massachusetts Institute of Technology.

132. Formerly Chief Engineer of the Sanitary District of Chicago.

133. From “Sewage,” by Samuel Rideal, 1900, p. 16.

134. See Am. Civil Engineers’ Pocket Book, Second Edition, p. 982.

135. Trans. Am. Society Civil Engineers, Vol. 58, 1907, p. 988.

136. Not defined by the American Public Health Association.

137. Trans. Am. Society Civil Engineers, Vol. 78, 1915, p. 892.

138. Removal of Suspended Matter by Sewage Screens, Cornell Civil Engineer, 1914. Abstracted in Engineering and Contracting, Vol. 41, 1914, p. 451.

139. “The Clarification of Sewage by Fine Screens,” Trans. Am. Society Civil Engineers, Vol. 78, 1915, p. 1000.

140. Langdon Pearse, Trans. Am. Society Civil Engineers, Vol. 78, 1915, p. 1000.

141. Meshes per inch.

142. See article by Henry Ryon in Cornell Civil Engineer, 1910.

143. The hydraulic coefficient is defined as the rate of settling in mm. per second.

144. Definition suggested by the American Public Health Association.

145. Computed from formula by Gilbert in “Transportation of Debris by Running Water,” U. S. Geological Survey, Professional Paper No. 86, 1914. Diameter in mm. = 1.28 (velocity)^2.7
Sp. gv. - 1.

146. Computed from Annual Report of the Superintendent of Sewers, Nov. 30, 1919, and 1920.

147. These figures are for 1919.

148. These figures are for 1905.

149. These figures are for 1902.

150. Report of the Ohio State Board of Health, 1908, page 425.

151. Definition proposed by the Am. Public Health Assn.

152. See Eng. News. Vol. 73, 1915, p. 410.

153. Sewage Treatment from Single Houses and Small Communities, by L. C. Frank. U. S. Public Health Service, Bulletin 101, 1920.

154. Eng. News-Record, Vol. 78, 1917, p. 566.

155. Municipal Engineering, Vol. 54, p. 149.

156. Eng. Record, Vol. 68, 1913, p. 452.

157. Am. Sewerage Practice, Vol. III, p. 437.

158. Trans. Am. Society Civil Engineers, Vol. 83, 1920, p. 337.

159. Eng. News-Record, Vol. 83, 1919, p. 510.

160. See Eng. News, Vol. 70, 1913, p. 1112; Eng. Record, Vol. 68, 1913, p. 440, and Eng. News, Vol. 75, 1916, p. 1028.

161. See Eng. Record, Vol. 67, 1913, p. 232.

162. The use of half-spray nozzles is not always advocated as it is considered that their use does not markedly improve the distribution. Where half nozzles are used, a margin of 18 inches to 2 feet should be allowed between the edge of the filter and the nozzle, to prevent the blowing of raw sewage from the filter.

163. From paper by E. G. Bradbury in Proceedings of the Ohio Eng. Society, 1910, p. 79.

164. The effective size of sand is the diameter in millimeters of the largest grain in that 10 per cent, by weight, of the material which contains the smallest grains.

165. The uniformity coefficient is the ratio of the diameter of the largest particle of the smallest 60 per cent, by weight, to the effective size.

166. Interest at 6 per cent.

167. Worcester figures.

168. This method may show a profit from the sale of sludge.

169. Sewage Disposal, 1919, p. 223.

170. See Eng. News, Vol. 9, 1883, p. 203, and Vol. 29, 1893, p. 27.

171. American Sewerage Practice, Vol. III.

172. Reference 11, at end of this chapter.

173. Reference 15.

174. Reference 2.

175. For mechanical methods of drying sludge, see Reference 22, p. 1127, and No. 33, p. 843.

176. Reference 10.

177. Reference 13.

178. University of California, Bulletin 251, 1915.

179. Reference 25.

180. See Report by Black & Phelps of Metropolitan Sewerage Commission, 1911, reprinted as Vol. VII of Contributions from the Sanitary Research Laboratory of the Massachusetts Institute of Technology.

181. See Reports, Mass. State Board of Health.

182. Reference 47.

183. Reference 10.

184. Reference 10.

185. Reference 10.

186. Hatton, reference 33.

187. Reference 18.

188. Reference 1, at end of this chapter.

189. Reference 2.

190. Reference 6.

191. Reference 5.

192. Reference 6.

193. Reference 6.

194. Reference 8.

195. Reference 20.

196. Reference 17.

197. Reference 19.

198. Reference 21.

199. Reference 24.

200. Inorganic Chemistry, by Alexander Smith.

201. American Public Health Association definition.

202. Sewage Sludge by Allen.

203. Sewage Disposal by Kinnicutt, Winslow and Pratt.

204. Sewage Disposal by Fuller.

205. Sewage Sludge by Allen.

206. From Eng. News-Record, Vol. 84, 1920, p. 995.

207. A Simple Mechanical Control for Dosing Sewage Beds, by P. Thompson, Eng. News-Record, Vol. 84, 1920, p. 1018.

208. Sewage Disposal by Kinnicutt, Winslow and Pratt.

209. Design of Siphon by G. H. Bayles, Eng. News-Record, Vol. 84, 1920, p. 974.

TRANSCRIBER’S NOTES

Silently corrected typographical errors and variations in spelling.
Archaic, non-standard, and uncertain spellings retained as printed.

Clyx.com