Guest Column | February 12, 2015

Math Solutions: Simulating Jar Test Results

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.

The U.S. EPA states that “For any given wastewater, the optimal treatment strategy should be determined by jar testing” (EPA 832-F-00-018, 2000), so it stands to reason that this is an important aspect of operator training.

The following is a hypothetical wastewater scenario presented with a three-step instructional method to simulating jar test results:

Jar testing determined the best liquid alum dose is 6.1 mg/L. The aluminum sulfate has a specific gravity of 1.26 and the solution has a strength of 52.2 percent. The wastewater treatment plant operates 24 hours per day with a flow rate of 625 GPM. How much liquid alum will be needed in the waste stream to produce these jar test results?

Calculate pounds of alum per day:

Calculate gallons of alum per day:

Calculate milliliters per minute (mL/min) of alum:

Complete playlist of Wastewater Dan’s Math Solutions      

This is the Simulating Jar Test Results 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.