Gravity-fed belt filters

These filters are widely used with biological sludge. They need only polyelectrolyte conditioning (3 to 5 kg t of DS) and lend themselves to continuous operation. Tliey have few manpower requirements but yield a cake with only moderate dryness  

For oily sludge (5 to 10% oils measured on DS), i.e. in refineries, there are references but they are few and far between. This is because operation is based on the need for continuous dual body feeding  

Under diese conditions, cake dryness may reach 40 to 45%. 

The lifetime of the cloth can be short (abrasion, plugging, etc.) ranging from 2000 to 4000 hours. 

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