Convert a target dose into pounds per day and gallons per day of product.
Chemical Feed Rate
Formula
Active, lb/d = Q, MGD x Dose, mg/L x 8.34 Product, lb/d = Active / (Strength / 100) Product, gpd = Product lb/d / (8.34 x SG) mL/min = gpd x 3,785.41 / 1,440
Inputs used
- Flow (MGD)
- Dose (as the active chemical) (mg/L)
- Product strength (active) (%)
- Product specific gravity
Worked example (White River WRRF, fictional)
- Active = 8.0 x 20 x 8.34 = 1,334.4 lb/d
- Product = 1,334.4 / 0.485 = 2,751.3 lb/d
- Volume = 2,751.3 / (8.34 x 1.33) = 248.0 gpd
- Pump = 248.0 x 3,785.41 / 1,440 = 652 mL/min
Tips
- Product strength and density come from the supplier SDS or certificate of analysis.
Results are estimates for operator use. Check units and inputs, and confirm decisions with plant data and procedures.