3.3 Dissolved Air Flotation (DAF)

Which method of flotation relies on the natural buoyancy of particles in water?

• Dispersed air flotation

• Induced air flotation

• Vacuum flotation

• Gravity flotation

What is "white water" in the context of DAF processes?

• Highly purified water

• Water saturated with dissolved air bubbles

• Water mixed with chemicals for coagulation

• Water with high mineral content

Which type of dissolved air system uses pressure to dissolve air into water?

• Open pressurized system

• Closed pressurized system

• Atmospheric air system

• Vacuum air system

What is the main purpose of air dissolution in DAF processes?

• To remove dissolved gases from water

• To increase water temperature

• To create air bubbles for flotation

• To neutralize acidic water

How is air distributed in a DAF unit to maximize the contact with particles?

• Through a single large pipe

• Through multiple small pipes or diffusers

• By releasing air directly into the sludge

• By using a fan to blow air over the water surface

What is the purpose of thickening primary sludge in wastewater treatment?

• To increase its volume

• To decrease its volume

• To change its color

• To remove odor

Why is mass balance important in DAF processes?

• To calculate the cost of operation

• To ensure compliance with environmental regulations

• To maintain a consistent sludge density

• To calculate the efficiency of the flotation process

Why is controlling air bubble size important in DAF processes?

• Large bubbles enhance flotation efficiency

• Small bubbles improve flotation efficiency

• Bubble size does not affect the efficiency

• Controlling bubble size is not necessary in DAF processes

How does controlling pH contribute to DAF processes?

• It affects the color of the treated water

• It enhances coagulation

• It regulates the dissolved oxygen level

• It prevents corrosion of DAF unit components

What is surface tension in the context of DAF processes?

• The force that holds water molecules together at the surface

• The density of particles in water

• The pressure inside the DAF unit

• The temperature at which water boils