Page 29 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

xxviii Contents

21.2.2.4 Softening Reactions .................................................................................................... 668
21.2.2.5 Lime-Soda Process...................................................................................................... 669
21.2.3 Chemistry of Metals................................................................................................................... 669
21.3 Practice .................................................................................................................................................... 670
21.3.1 Lime Softening........................................................................................................................... 670
21.3.2 Precipitation of Heavy Metals.................................................................................................... 670
21.3.2.1 Common Chemical Reactions .................................................................................... 670
21.3.2.2 Case: Mine Drainage .................................................................................................. 671
21.3.3 Precipitation of Anions............................................................................................................... 671
21.3.3.1 Phosphate Precipitation............................................................................................... 671
21.3.3.2 Cyanide Precipitation.................................................................................................. 672
Problems............................................................................................................................................................. 672
Acknowledgment................................................................................................................................................ 672
Glossary.............................................................................................................................................................. 672
References .......................................................................................................................................................... 675

PART V Biological Treatment

Chapter 22 Biological Processes and Kinetics...................................................................................................................... 679
22.1 Background.............................................................................................................................................. 679
22.1.1 1880–1980.................................................................................................................................. 679
22.1.2 Practice ....................................................................................................................................... 679
22.1.3 Theory......................................................................................................................................... 679
22.1.4 Definitions .................................................................................................................................. 680
22.1.4.1 Reaction Classifications.............................................................................................. 680
22.1.4.2 BOD Nomenclature .................................................................................................... 681
22.1.4.3 Surrogates for Active Biomass Concentration, X....................................................... 681
22.1.5 Wastewaters................................................................................................................................ 681
22.1.5.1 Municipal Wastewaters............................................................................................... 681
22.1.5.2 Industrial Wastes......................................................................................................... 681
22.1.5.3 Contaminants .............................................................................................................. 683
22.2 Cell Metabolism ...................................................................................................................................... 683
22.2.1 Metabolic Reactions ................................................................................................................... 684
22.2.1.1 Catabolism .................................................................................................................. 684
22.2.1.2 Anabolism................................................................................................................... 685
22.2.1.3 Cell Division............................................................................................................... 686
22.2.1.4 Photosynthesis............................................................................................................. 686
22.2.1.5 Energy Principles........................................................................................................ 686
22.3 Biological Treatment Overview .............................................................................................................. 687
22.3.1 Composition of Substrates.......................................................................................................... 687
22.3.1.1 Domestic Wastewater and Organic Compounds........................................................ 687
22.3.1.2 Industrial Wastewaters................................................................................................ 688
22.3.2 Composition of Cells.................................................................................................................. 688
22.3.2.1 Empirical Formulae for Cells ..................................................................................... 688
22.3.3 Biological Reactions................................................................................................................... 688
22.3.3.1 Substrate to Cells ........................................................................................................ 688
22.3.3.2 Heterotrophic .............................................................................................................. 689
22.3.3.3 Autotrophic Involving Nitrogen ................................................................................. 689
22.3.3.4 Anaerobic.................................................................................................................... 690
22.3.3.5 Balancing Equations by Half-Reactions..................................................................... 691
22.4 Cell Yield................................................................................................................................................. 692
22.4.1 Cell-Yield Calculation................................................................................................................ 692
22.4.2 Cell Maintenance and Endogenous Respiration ........................................................................ 693