Page 30 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Contents xxix

22.4.2.1 Cell Maintenance ........................................................................................................ 693
22.4.2.2 Endogenous Respiration ............................................................................................. 693
22.4.2.3 Microbial Growth Curve and Debris Accumulation .................................................. 694
22.4.3 Net Cell Yield, Y(net)................................................................................................................. 694
22.4.3.1 Cell Mass Relations .................................................................................................... 694
22.4.3.2 Cell Mass Rate Relations............................................................................................ 694
22.4.4 Decline in Degradable VSS ....................................................................................................... 695
22.4.5 Cell-Yield Data........................................................................................................................... 695
22.5 Kinetics of Biological Reactions............................................................................................................. 695
22.5.1 Monod Description of Biological Reactions.............................................................................. 695
22.5.2 K s as the Half-Saturation Constant............................................................................................. 695
22.5.3 Net Specific Growth Rate, m(net) .............................................................................................. 696
22.5.4 Temperature Effect..................................................................................................................... 697
22.5.5 Evaluation of Kinetic Constants................................................................................................. 697
22.5.5.1 Data on Kinetic Constants.......................................................................................... 697
22.5.6 Andrews=Haldane Model of Substrate Inhibition...................................................................... 697
22.5.7 Kinetic Parameters...................................................................................................................... 698
22.5.7.1 Specific Substrate Utilization Rate, U ........................................................................ 698
22.5.7.2 F=M Ratio ................................................................................................................... 700
22.5.7.3 Conversion F=M to U ................................................................................................. 700
22.5.7.4 Relating Monod Kinetics to U.................................................................................... 701
22.5.7.5 Sludge Age, u c ............................................................................................................ 701
m
22.5.7.6 Minimum Cell Regeneration Time, u ...................................................................... 701
c
22.5.7.7 Relationship between U and u c .................................................................................. 701
22.5.8 Nitrification=Denitrification........................................................................................................ 701
22.5.8.1 Nitrification: NH 4 to NO 3 ...................................................................................... 701
þ

22.5.8.2 Denitrification: NO 3 to N 2 Gas ................................................................................ 702

22.5.9 Phosphorous Uptake................................................................................................................... 702
22.5.9.1 Occurrence in Wastewaters......................................................................................... 702
22.5.9.2 Uptake to Cells ........................................................................................................... 702
22.5.9.3 Theory......................................................................................................................... 702
22.5.9.4 Technologies............................................................................................................... 703
22.6 Summary.................................................................................................................................................. 703
Problems............................................................................................................................................................. 703
Acknowledgments .............................................................................................................................................. 704
Appendix 22.A: Proteins ................................................................................................................................. 704
22.A.1 Protein Molecules....................................................................................................................... 704
22.A.2 Urea ............................................................................................................................................ 705
22.A.3 ATP ............................................................................................................................................ 705
Appendix 22.B: Michaelis–Menten Equation................................................................................................. 705
22.B.1 Enzyme Kinetics......................................................................................................................... 705
Glossary.............................................................................................................................................................. 707
References .......................................................................................................................................................... 718

Chapter 23 Biological Reactors ............................................................................................................................................ 721
23.1 Biological Reactor Spectrum................................................................................................................... 721
23.2 Activated Sludge...................................................................................................................................... 721
23.2.1 History ........................................................................................................................................ 721
23.2.1.1 Beginnings .................................................................................................................. 721
23.2.1.2 From Empiricism to Science ...................................................................................... 724
23.2.1.3 Milestones................................................................................................................... 724
23.2.1.4 Modern History........................................................................................................... 725
23.2.2 Activated-Sludge Reactor Analysis............................................................................................ 725
23.2.2.1 Materials Balance........................................................................................................ 726
23.2.2.2 Conventional Activated Sludge .................................................................................. 727
23.2.2.3 Extended Aeration ...................................................................................................... 729