The following table shows the meaning of the variables appearing in this tab, as well as their default values and their generally acceptable range. Note that due to the manner by which the variables are used by the sizing and costing equations, the range of acceptable values may be further reduced.
|
Variable |
Default Value |
Range |
|
|
||
|
◙ Volume |
0.0 L |
Positive |
|
◙ Max Volume |
15,000,000 L |
Positive |
|
○ Tank Depth |
2.0 m |
Positive |
|
○ Length / Width |
2.5 |
Positive |
|
● Length |
0.0 m |
Positive |
|
● Width |
0.0 m |
Positive |
Symbol Key: ○ User-specified value (always input); ● Calculated value (always output); ◙ Sometimes input, sometimes output
In Design Mode, the user specifies the Maximum Volume, the basin’s depth and the Length to Width ratio and the system computes the Number of Units and the Volume of the basin, as well as its length and width. In the Volumes tab of the operation interface, the user specifies the hydraulic residence time (tR) and the working to vessel volume ratio. The working (liquid) volume (Vw) and the vessel volume (V) are calculated using the following equations:
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|
|
|
Where F is the feed volumetric flowrate. If the calculated vessel volume exceeds its maximum possible value (specified through the Equipment tab), the system assumes multiple, identical units operating in parallel with a total vessel volume equal to the calculated. The tank depth is always specified by the user. Then, using the Length/Width ratio, the program calculates all the dimensions of the tank(s).
In Rating Mode, the user specifies the Number of Units, the Volume and the basin’s depth and length to width ratio.
The equipment purchase cost is based on the total vessel volume. By default it is calculated by the program’s built-in model for an Aeration Basin, with a minimum costing volume of 200 m3.
For more information on this equipment, see Well-Mixed (WM) Aeration Basin.
For information on the left-hand side variables and options, see Equipment Data Dialog: Equipment tab.
