The Plug Flow Aerobic BioOxidation (PFAB) model can simulated any number of parallel or sequential reactions that may represent biochemical oxidation, hydrolysis, chemical oxidation, photolysis, nitrification, etc. The PFAB model assumes that axial mixing is negligible.
● Kinetic Plug-Flow (PF) Aerobic Bio-Oxidation Procedure
For a component A that enters a PFAB unit, the component balance equation is given by the following equation:
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or:
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where F is the feed volumetric flowrate, Cin is the inlet concentration, C is the outlet concentration, A is the cross sectional area of the liquid flow, L is the total liquid flow length in the reactor (it depends on the number of compartments and the orientation of the compartments), and rA is the combined reaction rate of component A, given by:
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where rAj is the reaction rate of component A due to reaction j and q is the overall number of reactions. If k is the rate reference component of reaction j, then, the reaction rate of component A due to reaction j is given by the following equation:
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where nAj and nkj are the stoichiometric coefficients of components A and k in reaction j and can be specified on mass or molar basis. Negative stoichiometric coefficients are used for reactants and positive for products. The general rate expression (based on the rate reference component and for Monod-type of substrate expressions) of a reaction j is given by the following equation:
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where Kmax is the maximum rate constant, Ks is the half saturation constant for the substrate, C0 is the concentration of a second substrate component (e.g., oxygen), K0 is the half saturation constant for the other substrate component, and X is the biomass concentration. Alternative expressions for the substrate and second substrate terms are also available. The component databank includes data for Kmax and Ks for a large number of chemical components.
The above equations written for each component entering a PFAB unit constitute a system of ordinary differential equations which are integrated numerically to calculate the composition of the outlet stream.
Sorption and VOC emissions initialization and calculations are identical to those of the Aeration Basin (see WM Stoichiometric Aerobic Bio-Oxidation: Modeling Calculations).
See Vessel Sizing (Continuous Operations).
1. Corsi, R. L., and T. R. Card. 1991. “Estimation of VOC Emissions Using the BASTE Model,” Environmental Progress. 10: 290-299.
2. Eckenfelder, W.W., Jr., 1989, Industrial Water Pollution Control, McGraw-Hill, NY.
The interface of this operation has the following tabs:
● Oper. Cond’s, see Aerobic Bio-Oxidation Operations: Oper. Conds Tab
● Volumes, see Continuous Vessel Operations (Design Mode): Volumes Tab and Continuous Vessel Operations (Rating Mode): Volumes Tab
● Reactions, see Environmental Reaction Kinetics Dialog
● Vent/Emissions, see Agitated Tank Operations: Vent/Emissions Tab
● Sorption, see Environmental Reaction Operations: Sorption Tab
● Profiles, see Kinetic Reaction Operations: Profiles Tab
● Labor, etc, see Operations Dialog: Labor etc. Tab
● Description, see Operations Dialog: Description Tab
● Batch Sheet, see Operations Dialog: Batch Sheet Tab
● Scheduling, see Operations Dialog: Scheduling Tab
