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Sludge Conditioning & Polymer Dosing

Conditioning aggregates sludge particles and releases bound water so that mechanical dewatering can work. Getting the polymer type and dose right is the single biggest lever on cake dryness and capture rate.

Why Sludge Resists Dewatering

Bound Water

Much of a sludge's water is bound to particles and biofloc and will not release under pressure without conditioning.

Negative Charge & Fines

Charged fines stabilise the sludge and blind filter media, lowering capture and cake dryness.

Variable Sludge

Sludge character varies with origin and age, so conditioning must be tuned, not fixed.

Conditioning Chemistry & Measurement

Charge Demand

Streaming-current titration quantifies the cationic polymer demand to neutralise the sludge charge.

Capillary Suction Time

CST measures how readily a conditioned sludge releases water, guiding polymer type and dose.

Floc Formation

High-molecular-weight polymers bridge particles into strong, shear-resistant flocs that dewater cleanly.

Capillary Suction Time — the Conditioning Test

Capillary Suction Time (CST) measures the time for filtrate to travel a set distance through filter paper under capillary suction. A well-conditioned sludge releases water quickly and shows a low CST; over- or under-dosing raises it. Plotting CST against polymer dose reveals the optimum, the point of minimum CST, which transfers directly to the dewatering plant's polymer set-point and is re-checked as sludge character changes.

Conditioning Systems

Polymer Make-Up Units

Automatic preparation and ageing of emulsion or powder polymer to full activity.

Dosing & Mixing

Metered dosing with controlled flocculation mixing ahead of the dewatering unit.

Charge Control

Streaming-current control optimises dose in real time as sludge varies.

Planning a sludge treatment and dewatering train?

Reynolds & Bauhm engineers complete sludge treatment trains — thickening, conditioning, dewatering, stabilisation and drying — matched to your solids and disposal route.

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.