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In sludge drying the moisture from sludge is removed as water vapour by heating, rather than being removed as a liquid via mechanical means such as in thickening or dewatering. The sludge is normally dried to solid concentrations above 65% to produce pellets or, at the highest solids concentrations of 90% or more, a powder. Pelleted or powdered sludge is more readily conveyed than the dewatered sludge of higher water content, which exists as large lumps.

Drying related videos

Simulation of rotary dryer operation, Dynamis Source: Dynamis / YouTube

Simulation of rotary dryer operation, Dynamis

A simulation of rotary dryer operation, produced by Dynamis.


Drying features and blogs

Fig. 4.  SP filtrate and acidified sludge samples

Phosphorus recovery by sludge acidification and dewatering

A pilot-scale Danish study of phosphorus extraction from acidified anaerobic and aerobic sludge samples has revealed removal to be more effective from anaerobic sludges, even though the digested sludge alkalinity increases the total acid demand.

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