Circumference, Area, and Volume - Basic Mathematics for Water and Wastewater Operators - page 159

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Circumference,
Area, and Volume

Area = L × W Area of circle = 0.785 × D 2 Volume = L × W × D

Water/wastewater treatment plants consist of a series of tanks and channels. Proper
operational control requires the operator to perform several process control calcula-
tions involving parameters such as the circumference, perimeter, area, or volume of a
tank or channel. Many process calculations require computation of surface areas. To
aid in performing these calculations, the following definitions are provided:

Area —The area of an object, measured in square units.
Base —The bottom leg of a triangle, measured in linear units.
Circumference —The distance around an object, measured in linear units.
When determined for other than circles, it may be called the perimeter of
the figure, object, or landscape.
Cubic units —Measurements used to express volume (e.g., cubic feet, cubic
meters).
Depth —The vertical distance from the bottom the tank to the top. It is nor-
mally measured in terms of liquid depth and given in terms of sidewall
depth (SWD), measured in linear units.
Diameter —The distance, measured in linear units, from one edge of a circle
to the opposite edge passing through the center.
Height —The vertical distance, measured in linear units, from one end of an
object to the other.
Length —Distance, measured in linear units, from one end of an object to the
other.
Linear units —Measurements used to express distance (e.g., feet, inches,
meters, yards).
Pi (π)—A number in the calculations involving circles, spheres, or cones (π =
3.14).
Radius— Distance, measured in linear units, from the center of a circle to the
edge.
Sphere— A container shaped like a ball.
Square units— Measurements used to express area (e.g., square feet, square
meters, acres).
Volume— The capacity of a unit (how much it will hold), measured in cubic
units (e.g., cubic feet, cubic meters) or in liquid volume units (e.g., gallons,
liters, million gallons).
Width— Distance from one side of a tank to the other, measured in linear units.

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