Guest Column | October 28, 2014

Math Solutions: Poundage Calculations

Wastewater Dan Theobald

By Daniel Theobald, "Wastewater Dan"

Water Online’s “Math Solutions,” presented by wastewater consultant and trainer Dan Theobald (“Wastewater Dan”), instructs operators on poundage calculations.

Plant operations or certification exams may require operators to figure out gallons/flow, concentration of parameters, or other calculations related to poundage. Depending on your required math solution, calculations and unit of expression require explicit formulas.

Some common poundage calculations are accessible below:

Calculate Pounds

Calculate pounds of lime in slurry tank (using concentration as %):

Calculate pounds of solids in sludge tank (using concentration as milligrams per liter [mg/L]):

Calculate pounds of biochemical oxygen demand (BOD)/day (using flow):

Calculations Using Pounds

Calculate gallons in aeration tank using pounds of solids:

Calculate BOD mg/L per day using flow and pounds:

Complete playlist of Wastewater Dan’s Math Solutions

This is the Poundage 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.