Sludge Thickening & Dewatering Calculator

WAS → thickener → dewatering → cake · polymer demand · bio-P release warning

iWhat this tool does

Sludge leaves the clarifier at ~0.5–1 % solids — mostly water you pay to haul. This tool runs the volume chain from WAS to dewatered cake, sizes gravity thickening where it is allowed, warns loudly where it is not (bio-P sludge), compares dewatering technologies, and computes polymer demand.

1Sludge feed

Sludge DS (WAS)^[1]kg DS/d

Feed solids^[2] (0.5–3 %)% TS

Bio-P plant (EBPR sludge)

Mixed with primary sludge

2Thickening

Thickening route

Gravity SLR^[1][2] (25–150)kg/m²·d

Thickened solids^[2] (3–6)% TS

3Dewatering

Technology

Cake solids^[3] (18–45)% TS

Polymer dose^[3] (2–8)kg/t DS

Results — volume chain

Feed volume

—m³/d

After thickening

—m³/d

Cake to disposal

—t/d

Item	Value	Unit

Thickener & polymer

Item	Value	Unit

Sludge-area instrumentationMAPPED TO OUR RANGE

Thickeners / presses are mechanical equipment, not our line — process instruments we carry and quote at factory-direct price:

Duty	Instrument	Model / spec	Qty

Quote the sludge-area instruments at factory price

Flow meters on feed/underflow, blanket level and MLSS on reject streams — at the manufacturer's ex-works price, our margin solely from the export tax rebate.

Request a quote for this duty ← Size the bio-reactor (WAS source) Design Manual home

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Sources & parameter basis

[1]	EN 12255-8 (2024) — gravity thickening incl. bio-P sludge prohibition, SLR by sludge type, SRT ≤1.5 d, tank geometry.
[2]	Metcalf & Eddy 5th ed. / Andreoli et al. — gravity SLR table (primary 100–150, mixed 40–80, WAS 20–50 by SVI), feed & thickened concentrations.
[3]	Spans / CPCB sludge guide — dewatering cake ranges (belt 18–28, centrifuge 20–30, filter press 25–45, screw 18–25), cationic PAM dose 2–8 kg/t DS, screw-press energy.

Bio-P rule. Never gravity-thicken sludge from an enhanced-bio-P plant: the sludge releases phosphate under anoxic/anaerobic conditions in the thickener and the P-rich supernatant recycles to the head of the plant — undoing the removal you paid for. Use DAF / mechanical thickening, or co-thicken with primary sludge.

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