3.7 Sludge treatment and handling

What is the main principle behind gravity thickening?

• Increasing sludge volume

• Reducing sludge volume and improving dewatering

• Enhancing sludge odor

• Mixing sludge with chemicals

Which statement about flotation thickening is true?

• It reduces sludge volume without improving dewatering.

• It requires high temperature.

• It involves settling of sludge particles under gravity.

• It uses air bubbles to float sludge particles to the surface.

What is the primary advantage of flotation thickening over gravity thickening?

• Lower cost

• Higher efficiency in reducing sludge volume

• Lower energy consumption

• Lesser space requirement

Which sludge dewatering method utilizes the principle of gravitational drainage through a porous medium?

• Vacuum filters

• Centrifuges

• Filter presses

• Sand drying beds

What is the main advantage of using solar drying beds for sludge dewatering?

• Low initial cost and simplicity

• High energy efficiency

• Rapid dewatering process

• Minimal land area required

What is the primary disadvantage of using sand drying beds for sludge dewatering?

• High initial cost

• Large land area requirement

• High energy consumption

• Limited sludge capacity

What is the primary advantage of belt filter presses for sludge dewatering?

• Higher energy consumption

• Continuous operation

• Lower efficiency

• Smaller space requirement

What is the primary purpose of a belt filter press in sludge dewatering?

• To increase sludge moisture content

• To separate liquid from sludge by squeezing it between two belts

• To add moisture to sludge

• To decrease sludge quantity

What is the role of a filter press in sludge dewatering?

• To compress sludge using high pressure

• To add moisture to sludge

• To separate liquid from sludge using vacuum

• To separate liquid from sludge using pressure and filter cloths

In centrifuges, the sludge is separated based on:

• Density

• Color

• Temperature

• Hardness