Page 19 - Fair, Geyer, and Okun's Water and wastewater engineering : water supply and wastewater removal

JWCL344_fm_i-xxx.qxd 8/26/10 5:51 PM Page xiii

Contents xiii
9.3 Theory of Backflow and Backsiphonage 309
9.3.1 Water Pressure 310
9.3.2 Siphon Theory 311
9.3.3 Backflow 316
9.4 Methods and Devices for the Prevention of Backflow and Backsiphonage 316
9.4.1 Air Gap 317
9.4.2 Barometric Loops 318
9.4.3 Atmospheric Vacuum Breakers 318
9.4.4 Hose Bib Vacuum Breakers 319
9.4.5 Pressure Vacuum Breakers 320
9.4.6 Double Check Valves with an Intermediate Atmospheric Vent 320
9.4.7 Double Check Valves 322
9.4.8 Double Check Detector Check 322
9.4.9 Residential Dual Check 323
9.5 Reduced Pressure Principle Backflow Preventer 324
9.6 Administration of a Cross-Connection Control Program 326
9.6.1 Responsibility 326
9.6.2 Dedicated Line 329
9.6.3 Method of Action 329

10. Introduction to Wastewater Systems 333
10.1 Sources of Wastewaters 336
10.2 System Patterns 338
10.3 Collection of Sanitary Wastewater 338
10.4 Collection of Stormwater 340
10.5 Collection of Combined Wastewater 342
10.6 Choice of Collecting System 343
10.7 Treatment and Disposal or Reuse of Wastewater 344
10.7.1 Wastewater Treatment Processes 344
10.7.2 Sludge Management and Disposal 345
10.7.3 Sizing of Wastewater Treatment Works 347
10.7.4 Disposal into Receiving Waters 349
10.7.5 Disposal onto Land 351
10.8 Disposal of Industrial Wastewater 352
10.9 Systems Planning Management and Costs 353
10.10 Individual Wastewater Systems 354

11. Hydrology: Rainfall and Runoff 357

11.1 Background 357
11.2 Collection of Hydrologic Data 358
11.2.1 Rain Gauging 359
11.2.2 Snow Surveys 359
11.2.3 Stream Gauging 359
11.2.4 Groundwater Studies 359
11.2.5 Evaporation 360