Chapter 1 BASICS OF MICROBIOLOGY
1.1 The Cell
1.2 Taxonomy andPhylogeny
1.3 Prokaryotes
1.3.1 Bacteria
1.3.2 Archaea
1.4 Eukarya
1.4.1 Fungi
1.4.2 Algae
1.4.3 Protozoa
1.4.4 Other Multicellular Microorganisms
1.5 Viruses
1.6 Infectious Disease
1.7 Biochemistry
1.8 Enzymes
1.8.1 EnzymeReactivity
1.8.2 Regulating the Activity of Enzymes
1.9 EnergyCapture
1.9.1 Electron and Energy Carriers
1.9.2 Energy and Electronlnvestments
1.10 Metabolism
1.10.1 Catabolism
1.10.2 Anabolism
1.10.3 Metabolism and Trophic Groups
1.11 Genetics andlnformation Flow
1.12 DeoxyribonucleicAcid (DNA)
1.12.1 TheChromosome
1.12.2 Plasmids
1.12.3 DNAReplication
1.13 RibonucleicAcid (RNA)
1.13.1 Transcription
1.13.2 Messenger RNA (mRNA)
1.13.3 Transfer RNA (tRNA)
1.13.4 Translation and the Ribosomal RNA(rRNA)
1.13.5 Translation
1.13.6 Regulation
1.14 Phylogeny
1.14.1 The Basics of Phylogenetic Classification
1.15 MicrobialEcology
1.15.1 Selection
1.15.2 Exchange of Materials
1.15.3 Adaptation
1.16 Tools to Study MicrobialEcology
1.16.1 Traditional Enrichment Tools
1.16.2 MolecularTools
1.16.3 MultispeciesModeling
1.17 Bibliography
1.18 Problems
Chapter 2 STOICHIOMETRY AND BACTERIAL ENERGETICS
2.1 An Example Stoichiometric Equation
2.2 EmpiricalFormulas for Microbial Cells
2.3 Substrate Partitioning and Cellular Yield
2.4 Energy Reactions
2.5 OverallReactions for Biological Growth
2.5.1 Fermentation Reactions
2.6 Energetics and Bacterial Growth
2.6.1 Free Energy of the Energy Reaction
2.7 Yield Coefficient and Reaction Energetics
2.8 Oxidized Nitrogen Sources
2.9 Bibliography
2.10 Problems
Chapter 3 MICROBIAL KINETICS
3.1 BasicRateExpressions
3.2 ParameterValues
3.3 Basic Mass Balances
3.4 Mass Balances on Inert Biomass and Volatile Solids
3.5 SolubleMicrobiaIProducts
3.6 NutrientsandElectronAcceptors
3.7 InputActiveBiomass ''
3.8 Hydrolysis ofParticulate and Polymeric Substrates
3.9 Inhibition
3.10 OtherAlternateRate Expressions
3.11 Bibliography
3.12 Problems
Chapter 4 BIOFILM KINETICS
4.1 MicrobialAggregation
4.2 Why Biofilms?
4.3 Theldealized Biofilm
4.3.1 SubstratePhenomena
4.3.2 TheBiofilmltself
4.4 TheSteady-StateBiofilm
4.5 TheSteady-State-Biofilm Solution
4.6 EstimatingParameterValues
4.7 AverageBiofilm SRT
4.8 CompletelyMixedBiofilmReactor
4.9 Soluble Microbial Products and Inert Biomass
4.10 Trendsin CMBRPerformance
4.11 NormalizedSurfaceLoading
4.12 Nonsteady-StateBiofilms
4.13 Special-CaseBiofilm Solutions
4.13.1 DeepBiofilms
4.13.2 Zero-OrderKinetics
4.14 Bibliography
4.15 Problems
Chapter 5 REACTORS
5.1 ReactorTypes
5.1.1 Suspended-GrowthReactors
5.1.2 BiofilmReactors
5.1.3 ReactorArrangements
5.2 Mass Balances
5.3 A Batch Reactor
5.4 A Continuous-Flow Stirred-Tank Reactor with Effluent
Recycle
5.5 APlug-FlowReactor
5.6 A Plug-Flow Reactor with Effluent Recycle
5.7 Reactors with Recycle of Settled Cells
5.7.1 CSrIR with Settling and Cell Recycling
5.7.2 EvaluationofAssumptions
5.7.3 Plug-Flow Reactor with Settling and Cell Recycle
5.8 UsingAlternateRateModels
5.9 Linking Stoichiometric Equations to Mass Balance
Equations
5.10 Engineering Design ofReactors
5.11 Reactorsin Series
5.12 Bibliography
5.13 Problems
Chapter 6 THE ACTIVATED SLUDGE PROCESS
Chapter 7 LAGOONS
Chapter 8 AEROBIC BIOFILM PROCESSES
Chapter 9 NITRIFICATION
Chaptor 10 DENITRIFICATION
Chapter 11 PHOSPHORUS REMOVAL
Chapter 12 DRINKING-WATER TREATMENT
Chapter 13 ANAEROBIC TREATMENT BY METHANOGENESIS
Chapter 14 DETOXIFICATION OF HAZARDOUS CHEMICALS
Chapter 15 BIOREMEDIATION
Appondlx A FREE ENERGIES OF FORMATION FOR VARIOUS CHEMICAL SPECIES,
25°
Appondlx B NORMALIZED SURFACE-LOADING CURVE
內容試閱:
Air sparging alters at least three aspects of fluidized bed
operation. First, the presence of the gas phase reduces the liquid
hold-up (8), which decreases the liquid detention time and
increases the water''s interstitial velocity. Second, these effects
of the gas phase modify how the solid carriers are expanded in
response to the upward water flow. Although the response is
complicated, bed aeration generally causes a decrease in the FBE
for the same QAcs. Chang and Rittmann (1994) and Yu and Rittman
(1997) discuss these interacting factors. Third, the input of the
energy from aeration increases the bed turbulence, which can result
in a significant increase in the biofilm detachment rate. Since
aerobic heterotrophic systems have high biomass yields and growth
potential (i.e., Smin iS very low), the added detachment rate is
not necessarily an impediment in terms of BOD removal and process
stability, although effluent suspended solids may be
increased.
Fluidized beds offer reduced volumes, due to their high specific
surface area. Liquid detention times can be as low as a few
minutes. The size advantage of flu- idized beds generally is
limited by the ability to transfer oxygen to the water and the
biofilm. Thus, surface loads for fluidized beds may be somewhat
lower than for the other biofilm systems. As a consequence,
volumetric loads probably cannot be increased in direct proportion
to the increase in specific surface area. However, the short liquid
detention times of fluidized beds are particularly advantageous for
aerobic treatment of low concentrations of contaminants, for which
the oxygen demand is relatively low.
One operating problem that arises in some situations is bed
stratification, which usually arises when the carrier particles are
not sufficiently uniform in size. The smaller particles accumulate
near the top and also experience a lower biofilm-detachment rate.
Over time, these smaller particles accumulate more biofilm than do
the larger particles, making them less dense, which increases their
degree of fluidization. The problem is that the continued expansion
of the stratified bed leads ultimately to entrainment of the
carrier particle''s in the effluent and recycle flows.Using a highly
uniform medium most effectively prevents bed stratification. Other
control measures include designing a conical section at the top of
the reactor to allow light particles to settle; installing a
mechanical shear device, such as a propeller mixer, to detach the
excess biofilm from the small particles; or withdrawing carriers
from the top of the bed for cleaning.
When the medium is uniform, the carrier particles do not
stratify, but instead circulate throughout the bed height. This
medium mixing can provide a perfor- mance advantage when the
substrate flux is in or near the low-load region and the effluent
recycle ratio is not large. Then, medium movement allows each
biofilm particle to spend some time near the column inlet-where the
substrate concentration is relatively high and biofilm growth
occurs-and some time near the column outlet-where the substrate
concentration is very low, but the already accumulated biofilm can
continue removing substrate. Movement of the biofilm particles
disconnects substrate utilization and biofilm accumulation at any
particular location. Therefore, biofilm grown at a concentration
well above Smin near the inlet can remove substrate to well below
Smm near the outlet (Rittmann, 1982). In this way, a
steady-state-biofilm process can sustain effluent concentrations
substantially below Snun, as long as the medium mixes, while the
substrate concentration changes across the reactor.
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