Coagulant Dose from Jar Test

Pure equivalent + product feed (lb/day, gal/day) for alum, ferric chloride, or PAC at the jar-test optimal dose.

Run the calculator

Example

You enter

Flow (MGD) 5
Jar-test optimal dose (mg/L) 20
Product alum_liquid

You get

Pure equivalent 834 lb/day
Product (lb/day) 1719.6
Product (gal/day) 155.1

Details, formula, and sources

pure_lb_day = flow_MGD × jar_dose_mg_L × 8.34 (mass-balance constant for water). product_lb_day = pure_lb_day / (strength_pct / 100). product_gal_day = product_lb_day / (sg × 8.34).

Metcalf & Eddy (Wastewater Engineering: Treatment and Resource Recovery, 5th ed.) by name; AWWA M37 (Operational Control of Coagulation and Filtration Processes) by name. Manufacturer product-strength + density values (alum 48.5% sg 1.33, ferric chloride 38% sg 1.40, PAC 10% sg 1.20).

Metcalf & Eddy / AWWA M37 licensed; jar-test methodology free in EPA SDWA training materials at epa.gov.

Estimate. Operator of record and primacy agency govern.

Field names used by the API: flow_mgd, jar_test_dose_mg_l, product, pure_lb_day, product_lb_day, product_gal_day

Constant 8.34 lb/gal water at 60 °Fphysical fact
Product strengths alum dry 100%, alum liquid 48.5%, ferric chloride 38%, PAC 10%manufacturer typical
Product specific gravities alum liquid 1.33, ferric 1.40, PAC 1.20manufacturer typical