Operator calculator
Chemical Feed Pump Setting calculator
Find the mL/min a metering pump must deliver for a target dose.
Calculator
Pump setting
262.8 mL/min
- 1. Chemical needed = 0.5 × 1,000,000 × 3.785 × 2 = 3,785,000 mg/day
- 2. Feed = 3,785,000 ÷ (10 × 1,440) = 262.8 mL/min
For instructional use. Results assume the standard conversion factors shown on this page. Actual field calculations may need chemical strength, density, temperature, and other adjustments, so check your plant’s procedures.
Formula and inputs
feed (mL/min) = [flow (MGD) × 1,000,000 gal × 3.785 L/gal × dose (mg/L)] ÷ [strength (mg/mL) × 1,440 min/day]
| Input | Unit |
|---|---|
| Plant flow | MGD |
| Dose | mg/L |
| Solution strength | mg/mL |
| Result: Pump setting | mL/min |
Conversion factors used: 3.785 L per gallon; 1,440 minutes per day; 1 MGD = 1,000,000 gpd.
When to use it
Metering pumps are set in mL/min or gal/day. This formula works from the plant flow, the dose you want, and the strength of the stock solution.
Solution strength in mg/mL is a common way to write concentration. A 1% solution is about 10 mg/mL.
Applies to: Water Treatment, Water Distribution.
Exam tip: Do the unit chain on paper: MGD to gal, gal to L, mg per day, then per minute.
Study guides
Build the math skill behind the calculator
Water Operator Math Made Simple walks through the formulas step by step.
Water Operator Math Made Simple
A Step-by-Step Guide to the Math Every Water Operator Needs to Know