Chapter XI: Construction

118. Elements. WORK OF THE ENGINEER. 119. Duties. 120.
Inspection. 121. Interpretation of Contract. 122. Unexpected
Situations. 123. Cost Data and Estimates. 124. Progress
Reports. 125. Records. EXCAVATION. 126. Specifications. 127.
Hand Excavation. 128. Machine Excavation. 129. Types of
Machines. 130. Continuous Bucket Excavators. 131. Cableway
and Trestle Excavators. 132. Tower Cableways. 133. Steam
Shovels. 134. Drag Line and Bucket Excavators. 135.
Excavation in Quicksand. 136. Pumping and Drainage. 137.
Trench Pump. 138. Diaphragm Pump. 139. Jet Pump. 140. Steam
Vacuum Pumps. 141. Centrifugal and Reciprocating Pumps. 142.
Well Points. 143. Rock Excavation. 144. Power Drilling. 145.
Steam or Air for Power. 146. Depth of Drill Hole. 147.
Diameter of Drill Hole. 148. Spacing of Drill Holes. SHEETING
AND BRACING. 149. Purposes and Types. 150. Stay Bracing. 151.
Skeleton Sheeting. 152. Poling Boards. 153. Box Sheeting.
154. Vertical Sheeting. 155. Pulling Wood Sheeting. 156.
Earth Pressures. 157. Design of Sheeting and Bracing. 158.
Steel Sheet Piling. LINE AND GRADE. 159. Locating the Trench.
160. Final Line and Grade. 161. Transferring Grade and Line
to the Pipe. 162. Line and Grade in Tunnel. TUNNELLING. 163.
Depth. 164. Shafts. 165. Timbering. 166. Shields. 167. Tunnel
Machines. 168. Rock Tunnels. 169. Ventilation. 170.
Compressed Air. EXPLOSIVES AND BLASTING. 171. Requirements.
172. Types of Explosives. 173. Permissible Explosives. 174.
Strength. 175. Fuses and Detonators. 176. Care in Handling.
177. Priming, Loading, and Firing. 178. Quantity of
Explosive. PIPE SEWERS. 179. The Trench Bottom. 180. Laying
Pipe. 181. Joints. 182. Labor and Progress. BRICK AND BLOCK
SEWERS. 183. The Invert. 184. The Arch. 185. Block Sewers.
186. Organization. 187. Rate of Progress. CONCRETE SEWERS.
188. Construction in Open Cut. 189. Construction in Tunnels.
190. Materials for Forms. 191. Design of Forms. 192. Wooden
Forms. 193. Steel-lined Wooden Forms. 194. Steel Forms. 195.
Reinforcement. 196. Cost of Concrete Sewers. BACKFILLING.
197. Method. 233–331

CHAPTER XII

MAINTENANCE OF SEWERS

198. Work Involved. 199. Causes of Troubles. 200. Inspection.
201. Repairs. 202. Cleaning of Sewers. 203. Flushing Sewers.
204. Cleaning Catch-basins. 205. Protection of Sewers. 206.
Explosions in Sewers. 207. Valuation of Sewers. 332–351

CHAPTER XIII

COMPOSITION AND PROPERTIES OF SEWAGE

208. Physical Characteristics. 209. Chemical Composition. 210.
Significance of Chemical Constituents. 211. Sewage Bacteria.
212. Organic Life in Sewage. 213. Decomposition of Sewage.
214. The Nitrogen Cycle. 215. Plankton and Macroscopic
Organisms. 216. Variations in the Quality of Sewage. 217.
Sewage Disposal. 218. Methods of Sewage Treatment. 352–371

CHAPTER XIV

DISPOSAL BY DILUTION

219. Definition. 220. Conditions Required for Success. 221.
Self-purification of Running Streams. 222. Self-purification
of Lakes. 223. Dilution in Salt Water. 224. Quantity of
Diluting Water Needed. 225. Governmental Control. 226.
Preliminary Treatment. 227. Preliminary Investigations. 372–382

CHAPTER XV

SCREENING AND SEDIMENTATION

228. Purpose. 229. Types of Screens. 230. Sizes of Openings.
231. Design of Fixed and Movable Screens. PLAIN
SEDIMENTATION. 232. Theory of Sedimentation. 233. Types of
Sedimentation Basins. 234. Limiting Velocities. 235. Quantity
and Character of Grit. 236. Dimensions of Grit Chambers. 237.
Existing Grit Chambers. 238. Number of Grit Chambers. 239.
Quantity and Characteristics of Sludge from Plain
Sedimentation. 240. Dimensions of Sedimentation Basins.
CHEMICAL PRECIPITATION. 241. The Process. 242. Chemicals.
243. Preparation and Addition of Chemicals. 244. Results. 383–409

CHAPTER XVI

SEPTICIZATION

245. The Process. 246. The Septic Tank. 247. Results of Septic
Action. 248. Design of Septic Tanks. 249. Imhoff Tanks. 250.
Design of Imhoff Tanks. 251. Imhoff Tank Results. 252. Status
of Imhoff Tanks. 253. Operation of Imhoff Tanks. 254. Other
Tanks. 410–430

CHAPTER XVII

FILTRATION AND IRRIGATION

255. Theory. 256. The Contact Bed. 257. The Trickling Filter.
258. Intermittent Sand Filter. 259. Cost of Filtration.
IRRIGATION. 260. The Process. 261. Status. 262. Preparation
and Operation. 263. Sanitary Aspects. 264. The Crop. 431–464

CHAPTER XVIII

ACTIVATED SLUDGE

265. The Process. 266. Composition. 267. Advantages and
Disadvantages. 268. Historical. 269. Aëration Tank. 270.
Sedimentation Tank. 271. Reaëration Tank. 272. Air
Distribution. 273. Obtaining Activated Sludge. 274. Cost. 465–479

CHAPTER XIX

ACID PRECIPITATION, LIME AND ELECTRICITY, AND DISINFECTION

275. The Miles Acid Process. ELECTROLYTIC TREATMENT. 276. The
Process. DISINFECTION. 277. Disinfection of Sewage. 482–493

CHAPTER XX

SLUDGE

278. Methods of Disposal. 279. Lagooning. 280. Dilution. 281.
Burial. 282. Drying. 495–505

CHAPTER XXI

AUTOMATIC DOSING DEVICES

283. Types. 284. Operation. 285. Three Alternating Siphons.
286. Four or More Alternating Siphons. 287. Timed Siphons.
288. Multiple Alternating and Timed Siphons. 506–512

SEWERAGE AND SEWAGE TREATMENT