Page 31 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

xxx Contents

23.2.2.4 Aerated Lagoon........................................................................................................... 729
23.2.2.5 Plug-Flow Reactor ...................................................................................................... 730
23.2.3 Numerical Modeling................................................................................................................... 732
23.2.3.1 Numerical Model Concept.......................................................................................... 733
23.2.3.2 IWA Activated-Sludge Model.................................................................................... 733
23.2.4 Practice ....................................................................................................................................... 733
23.2.4.1 Empirical Guidelines................................................................................................... 734
23.2.4.2 Experience with Plants................................................................................................ 737
23.2.5 Operation .................................................................................................................................... 737
23.2.5.1 Bulking Sludge ........................................................................................................... 738
23.3 Biofilm Reactors...................................................................................................................................... 739
23.3.1 Biofilms ...................................................................................................................................... 739
23.3.1.1 Structure...................................................................................................................... 739
23.3.1.2 Transport of Nutrients................................................................................................. 739
23.3.2 Biofilm Reactors Model ............................................................................................................. 739
23.3.2.1 Empirical Equation ..................................................................................................... 739
23.3.2.2 Trickling-Filter Spreadsheet Model............................................................................ 741
23.4 Anaerobic Reactors.................................................................................................................................. 741
23.4.1 Evolution of Separate Sludge Digestion .................................................................................... 741
23.4.2 Design Criteria............................................................................................................................ 742
23.4.2.1 High-Rate Digestion ................................................................................................... 742
23.4.3 Process Design Principles .......................................................................................................... 742
23.4.3.1 Reactions..................................................................................................................... 743
23.4.3.2 Kinetics ....................................................................................................................... 744
23.4.3.3 Influences on Reaction Velocity................................................................................. 744
23.4.3.4 Effect of Temperature................................................................................................. 745
23.4.3.5 Mixing......................................................................................................................... 745
23.4.3.6 Environmental Conditions .......................................................................................... 746
23.4.3.7 Materials Balance: Kinetic Model .............................................................................. 746
23.4.3.8 Practice........................................................................................................................ 746
23.4.4 Operation and Monitoring.......................................................................................................... 747
23.4.4.1 Process Upsets ............................................................................................................ 747
23.4.4.2 Indicators and Tests .................................................................................................... 747
23.4.4.3 Percent Reduction of Volatile Suspended Solids ....................................................... 747
23.5 Summary.................................................................................................................................................. 748
23.5.1 State of the Art ........................................................................................................................... 748
23.5.2 Parameters .................................................................................................................................. 748
Problems............................................................................................................................................................. 749
Activated Sludge...................................................................................................................................... 749
Bio-Filters ................................................................................................................................................ 750
Anaerobic................................................................................................................................................. 750
Acknowledgments .............................................................................................................................................. 751
Appendix 23.A: Biofilm Reactor Model......................................................................................................... 751
23.A.1 Biofilm Reactors Model ............................................................................................................. 751
23.A.1.1 Mathematics................................................................................................................ 752
23.A.1.2 Approximation Model by ‘‘Lumping’’ Coefficients................................................... 753
Glossary.............................................................................................................................................................. 754
References .......................................................................................................................................................... 754

Pre-Appendix Tables ............................................................................................................................................................. 757

Appendix A International System of Units.......................................................................................................................... 765

Appendix B Physical Constants and Physical Data............................................................................................................. 773