Guest Column | May 26, 2015

Math Solutions: Conversion 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”), instructs operators on specific math solutions for operator certification exam preparation.

This tool for operators — represented through video tutorials — offers mathematical templates for performing accurate wastewater calculations. Many operators are held back from advancing their license because they struggle with the mathematics portion of certification examinations. Conversion calculations, such as those demonstrated below, are among those that need to be understood by wastewater operators. In addition to operators, the calculations may serve educators, engineers, regulators, and others.

Conversion data is provided in many units of expression such as square miles, acres, or acre-feet/day, and also many different time increments including seconds, minutes, hours, or days. Depending on the calculation used with conversions, converting the unit or time of expression may be required for an accurate calculation.

Convert acres to square feet:


Convert square miles to acres:


Convert acre-ft./day to GPM:

Complete playlist of Wastewater Dan’s Math Solutions      

This is the Conversion Calculations presentation in my series of “Math Solutions.” 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.