Guest Column | September 13, 2014

Math Solutions: Volume Calculations

Wastewater Dan Theobald

By Daniel Theobald, "Wastewater Dan"

Water Online’s “Math Solutions” series, presented by wastewater consultant and trainer Dan Theobald (“Wastewater Dan”), provides an understanding of the sometimes difficult calculations involved in achieving wastewater operator certification.

Volume calculations may have different requirements. Results may be expressed as cubic feet, increment of millions, or even incorporating a time element in calculation solutions.

Depending on the calculation used with volume, calculations certain pipes or tanks (dictated by size/shape) may require explicit formula use.

Some common volume calculations are accessible below:

Calculate Volume

Cubic feet in a treatment tank:

Calculate volume in million gallons (MG):

Calculate cubic feet per second:

Calculate pipe volume in gallons:

Calculate gallons of sludge in a conical bottom circular tank:

This is the flow rate conversion calculations presentation in my series of “Math Solutions” (access the full playlist here). If you have specific wastewater math queries, please submit a question.

About Dan Theobald:

Known in the industry as “Wastewater Dan,” Daniel L. Theobald, proprietor of Environmental Services (, is a professional wastewater and safety consultant/trainer. He has more than 24 years of hands-on industry experience operating many variants of wastewater treatment processing units and is eager to share with others his knowledge about water conservation.

Theobald serves as an active consultant for industries looking to achieve and maintain improved wastewater treatment at reduced cost. He is a Lifetime Member of the Who’s Who Registry of Professionals and holds numerous certifications from wastewater management regulatory boards and professional organizations. Theobald contributed one chapter to the Water Environment Federation’s ( Manual of Practice # 37 (MOP-37), a technical manual resource guide for biological nutrient removal, published in 2013.