Page 17 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

xvi Contents

12.2.2 Emergence of Filtration Practice................................................................................................ 333
12.2.2.1 State of the Art, 1890 and 1990 ................................................................................. 334
12.2.2.2 Growth of Waterworks Industry................................................................................. 334
12.2.3 Progress in Filtration Practice .................................................................................................... 334
12.2.3.1 Dual Media ................................................................................................................. 335
12.2.3.2 Breaking the HLR Barrier .......................................................................................... 335
12.2.3.3 Alternative Modes of Filtration .................................................................................. 335
12.2.4 Modern Filtration Practice.......................................................................................................... 335
12.2.4.1 The Federal Role......................................................................................................... 335
12.2.4.2 Modern Practice.......................................................................................................... 335
12.3 Theory...................................................................................................................................................... 336
12.3.1 Quest of Theory.......................................................................................................................... 336
12.3.1.1 Dependent Functions in Filtration .............................................................................. 336
12.3.1.2 Definitions................................................................................................................... 336
12.3.2 Process Description .................................................................................................................... 336
12.3.2.1 Experimental C(Z) t Results of Eliassen...................................................................... 336
12.3.2.2 Experimental C(Z) t Results of Ives............................................................................. 337
12.3.2.3 C(Z, t) in Three Dimensions ....................................................................................... 337
12.3.2.4 Mass Transfer Similarities between Adsorption and Filtration.................................. 337
12.3.2.5 Relation between the C(Z) t Wave Front and the C(t) Breakthrough Curve ....... 337
Z¼Z o
12.3.2.6 Specific Solids Deposit, s(Z, t)................................................................................... 339
12.3.2.7 Clogging Front............................................................................................................ 339
12.3.2.8 Local Hydraulic Gradient, i(Z, t)................................................................................. 340
12.3.2.9 Rational Design........................................................................................................... 341
12.3.2.10 Total Headloss and Components of Headloss............................................................ 342
12.3.2.11 Characteristics of C(t) Z for a Filter Cycle .................................................................. 342
12.3.3 Mathematical Modeling.............................................................................................................. 344
12.3.3.1 Iwasaki’s Equations .................................................................................................... 344
12.3.3.2 Filter Coefficient ......................................................................................................... 346
12.3.3.3 Transport Coefficient .................................................................................................. 346
12.3.3.4 Attachment Coefficient ............................................................................................... 349
12.3.3.5 Effect of Attachment Efficiency on Filter Ripening................................................... 349
12.3.3.6 Derivation of Materials Balance Expression .............................................................. 350
12.3.4 Synthesis of a Model.................................................................................................................. 351
12.3.4.1 Solids Uptake Rate ..................................................................................................... 351
12.3.4.2 Conditions at Equilibrium........................................................................................... 352
12.3.4.3 Zones of Wave Front.................................................................................................. 353
12.3.5 Summary..................................................................................................................................... 353
12.4 Design...................................................................................................................................................... 353
12.4.1 External Parameters.................................................................................................................... 354
12.4.1.1 Design Decisions ........................................................................................................ 354
12.4.1.2 Cost ............................................................................................................................. 354
12.4.2 Components of Filter Design ..................................................................................................... 354
12.4.2.1 Layout of Filters ......................................................................................................... 354
12.4.2.2 Hydraulic Modes of Filtration .................................................................................... 355
12.4.2.3 Water Distribution ...................................................................................................... 355
12.4.2.4 Media .......................................................................................................................... 356
12.4.2.5 Pipe Gallery ................................................................................................................ 356
12.4.2.6 Clear-Well................................................................................................................... 358
12.4.2.7 Control Systems.......................................................................................................... 359
12.4.3 Filter Box.................................................................................................................................... 359
12.4.3.1 Filtration Rate ............................................................................................................. 359
12.4.3.2 Area of Filters............................................................................................................. 359
12.4.3.3 Net Water Production ................................................................................................. 359
12.4.3.4 Depth of Filter Box..................................................................................................... 359