6. Elaboration Question 1

Course subject(s) 6. Digestion of sludge and sewage

Question 1: Gravity Thickening

A wastewater treatment plant has a daily sludge waste flow of 1,000 m3/day. The waste sludge is 1% Suspended Solids (SS) of which 70% is organic matter. The sludge concentration after thickening is 50 g SS/l and the solids concentration in the effluent is 250 mg/l. The maximum solids loading rate is 40 kg SS/(m2·day) and the sludge residence time is approximately 1 day.

  • What is the diameter of the thickener?
  • What is the height of the sludge layer in the thickener?

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