CODECAL^® in pre-liming before centrifuge

 

CODECAL^® is introduced in the sludge as a powder before the centrifuge.  The reactivity delay enables the lime to remain as CaO during dewatering; the hydration reaction takes mainly place in the dewatered sludge at storage.

Until now, the dewatered sludge on centrifuge is mainly conditioned with polymers before dewatering and with quicklime after dewatering.

 

CODECAL^®  used in pre-liming avoids the mixing during post-liming with as first advantage to largely improve quality and homogeneity of sludge :

• Mixing before dewatering in liquid phase enables a perfect homogenisation of the mixture.
• When avoiding to mix sludge after dewatering makes that sludge does not destructure, "loose" its water, become more pasty.
• pH control of the filtrate enables to guarantee a permanent lime treatment and consequently a perfect sanitisation of the sludge.

 

Sludge obtained by a CODECAL^® pre-liming is similar to the one obtained on plate filter presses with regard to structure and homogeneity.

The particle size of the CODECAL^®  favours a real mineralisation of sludge; the centrifuge performances are consequently considerably improved :

• Increase of D.S. content and reduction of the sludge volume.
• Finely divised sludge structure with an angle of repose larger than 45°.

 
Traditional and CODECAL^® processes