Guest Column | September 9, 2015

Math Solutions: Real-Life Wastewater 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 wastewater treatment calculations.

The ongoing “Math Solutions” series was designed to prepare operators for certification exams, which themselves are preparation for day-to-day treatment plant operations. But for this segment, Wastewater Dan reverses course and prioritizes “real life” ahead of the classroom, addressing math problems encountered in the field and sent in by readers — though they could appear on exams as well.

When applying the following in real life, converting the unit or time of expression may be required for an accurate calculation.

Calculate pressure (psi) at tank bottom:

Calculate feet of water in tank:

Calculate weight of gallons in tank:

Calculate pounds of chlorine used in one year:

Calculate hours required for pump to run:

Complete playlist of Wastewater Dan’s Math Solutions   

This is the 'Real-Life Wastewater 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.

Image credit: "CDE AquaCycle A400 Thickener," Peter Craven © 2004, used under an Attribution 2.0 Generic license: