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Polymer Dose Calculator

Calculate polymer use in lb active per dry ton and the neat polymer feed needed for a target dose.

Polymer Dose (lb per dry ton)

Formula

Dry solids, lb/h = Feed gpm x 60 x 8.34 x %TS / 100
Active polymer, lb/h = Neat gph x density x %active / 100
Dose, lb/dry ton = Active polymer lb/h / (Dry solids lb/h / 2,000)
Inputs used
  • Sludge feed rate (gpm)
  • Sludge feed solids (%)
  • Neat (as received) polymer feed (gal/h)
  • Polymer active content (%)
  • Neat polymer density (lb/gal)

Worked example (White River WRRF, fictional)

  1. Dry solids = 99 x 60 x 8.34 x 0.0294 = 1,456 lb/h = 0.728 dry tons/h
  2. Active polymer = 5.2 x 8.8 x 0.40 = 18.30 lb/h
  3. Dose = 18.30 / 0.728 = 25.1 lb/dry ton

Neat Polymer Feed for a Target Dose

Formula

Neat gph = (Dry tons/h x Target lb/dry ton) / (Density x %active / 100)
Inputs used
  • Sludge feed rate (gpm)
  • Sludge feed solids (%)
  • Target dose (lb/dry ton)
  • Polymer active content (%)
  • Neat polymer density (lb/gal)

Worked example (White River WRRF, fictional)

  1. Active needed = 0.728 dry tons/h x 25 = 18.21 lb/h
  2. Neat feed = 18.21 / (8.8 x 0.40) = 5.17 gal/h

Tips

  • Typical centrifuge doses for digested sludge are often 15 to 35 lb active/dry ton.

Results are estimates for operator use. Check units and inputs, and confirm decisions with plant data and procedures.

This calculator also appears on ActivatedSludge.com, our consulting site. Results are for training and operator use; always follow your plant’s procedures.