Page 20 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Contents xix

13.5 Operation ................................................................................................................................................. 415
13.5.1 Plant Start-Up ............................................................................................................................. 415
13.5.2 Operating Tasks.......................................................................................................................... 415
13.5.2.1 Scraping ...................................................................................................................... 415
13.5.2.2 Rebuilding the Sand Bed............................................................................................ 416
13.5.3 Monitoring and Reporting.......................................................................................................... 416
Problems............................................................................................................................................................. 416
Acknowledgments .............................................................................................................................................. 418
Glossary.............................................................................................................................................................. 418
References .......................................................................................................................................................... 420

Chapter 14 Cake Filtration.................................................................................................................................................... 423
14.1 Description............................................................................................................................................... 423
14.1.1 Cake Filtration In-a-Nutshell...................................................................................................... 423
14.1.1.1 Applications ................................................................................................................ 423
14.1.1.2 Definitions................................................................................................................... 423
14.1.1.3 Phases of Operation .................................................................................................... 424
14.1.1.4 Process Description..................................................................................................... 424
14.1.1.5 DE Selection ............................................................................................................... 424
14.1.2 Media.......................................................................................................................................... 425
14.1.2.1 Kinds of Media ........................................................................................................... 425
14.1.2.2 Sources of Media........................................................................................................ 425
14.1.2.3 Manufacturing of Media............................................................................................. 426
14.1.2.4 Characteristics of Media ............................................................................................. 427
14.1.3 Attributes .................................................................................................................................... 427
14.1.4 History ........................................................................................................................................ 428
14.1.4.1 1940s’ Military Use of DE Filtration ......................................................................... 428
14.1.4.2 1950s’ Adaptation of DE for Municipal Use ............................................................. 429
14.1.4.3 Research...................................................................................................................... 430
14.2 Cake Filtration Process............................................................................................................................ 431
14.2.1 Particle Removal Effectiveness.................................................................................................. 431
14.2.1.1 Turbidity and Bacteria ................................................................................................ 431
14.2.1.2 Particle Counts............................................................................................................ 432
14.2.1.3 Iron and Manganese.................................................................................................... 432
14.2.1.4 Asbestiform Fibers...................................................................................................... 432
14.2.1.5 Biological Particles ..................................................................................................... 432
14.2.2 Removal Mechanisms ................................................................................................................ 433
14.2.2.1 Straining and Embedding ........................................................................................... 433
14.2.2.2 The Role of Body Feed .............................................................................................. 433
14.2.2.3 Adsorption................................................................................................................... 433
14.2.2.4 Comparisons between Filtration Processes................................................................. 433
14.2.3 Hydraulics................................................................................................................................... 433
14.2.3.1 Hydraulics of Cake Filtration ..................................................................................... 434
14.3 Design...................................................................................................................................................... 437
14.3.1 Diatomite Technologies.............................................................................................................. 437
14.3.1.1 Equipment................................................................................................................... 438
14.3.1.2 System Components ................................................................................................... 439
14.3.1.3 Layout ......................................................................................................................... 440
14.3.2 Design Parameters...................................................................................................................... 441
14.3.2.1 Variables ..................................................................................................................... 441
14.3.2.2 Guidelines and Criteria ............................................................................................... 441
14.3.3 Design Examples........................................................................................................................ 442
14.3.3.1 Data from 12 Plants.................................................................................................... 442
14.3.3.2 Plant Descriptions ....................................................................................................... 442
14.4 Operation ................................................................................................................................................. 445
14.4.1 Operating Protocol...................................................................................................................... 445