Types of water in sludges

From the technological viewpoint, content of water in sludge is its most important property. Sludges from municipal and industrial wastewaters can contain as much as 99.5% of water. It is impossible to dispose or 

When removing water, the state of the sludge is changed in addition to the change of the volume, which influences its properties, as shown in Table 3.68. 

FVom the aspects of the occurrence of water in sludge and the possibility of its separation, the types of waters are as follows  

Gravitational free water, which is in the cavities between sludge particles, is present in the highest amounts. This water can be removed very easily (for example, by several hours of sedimentation in so-called thickeners). 

When solid particles of sludge agglomerate, capillaries are formed between the sludge particles, and water present in them is bonded by capillary forces. To remove this water, it would be necessary to exert a force on the water-sludge mixture equal to the force binding this water. 

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