# Math Solutions: Simulating Jar Test Results

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:

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.