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Sludge reduction pays for itself

Sludge reduction pays for itself
A dissolved air flotation (DAF) sludge dewatering system installation from GEA Westfalia Separator has helped Hutchings and Harding not only reduce waste disposal costs but also potentially generate income from a new revenue source from their raw material. 

DAF systems use air to create microbubbles to which the solids attach and float to the surface to be skimmed off. "One of the disadvantages of such systems is the cost of disposal of the very wet waste," explains David Cawdery of GEA Westfalia Separator.

Hutchings and Harding is a renowned and long established tannery producing chamois leather from sheep pelts. The company utilises a DAF system to recycle and clean the water used in the processing of skins. "The largely liquid DAF sludge was previously transported off site to landfill and it was these costs that we were asked to reduce," says Cawdery.

Liquid/solid separation specialists at GEA Westfalia Separator UK prepared system designs and costing projections for reducing the amount of DAF sludge for disposal by approximately 45% to produce weekly disposal cost savings. The system they designed is based upon a UCD205 high efficiency decanter that is reliable, compact and simple to use and maintain. DAF sludge is fed to the decanter using a Seepex pump, designed for handling a high volume of fatty solids.

The installation includes a specially designed chemical dosing unit from Biochemica that supplies regulated amounts of polymer chemicals that help breakdown the solids and liquids in the DAF sludge to effect improved dewatering rates. The dosing rate is easy to adjust and together with decanter controls ensures the acceptable 'dryness' of the end waste product.

"Now that the equipment is installed and working at production capacity we are seeing an actual 90% reduction in the DAF sludge, through the system," says John Ettling, Managing Director at Hutchings and Harding.
GEA Westfalia Separator Ltd

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