The video tutorial explains multimedia filters, which reduce suspended solids and turbidity in process water. It covers the construction of these filters, detailing the four layers: anthracite, quartz sand, garnet, and gravels. The operation of multimedia filters is discussed, highlighting the graded layers and filtration efficiency. Valve arrangements and their functions are explained, followed by a description of the service flow and backwash process. The tutorial concludes with steps for backwashing and troubleshooting high differential pressure issues.

What is the primary function of a multimedia filter?

• To change the color of water

• To add minerals to water

• To reduce suspended solids and turbidity

• To increase water temperature

Which layer is at the top in a multimedia filter?

• Garnet

• Quartz sand

• Anthracite coal

• Supporting gravels

Why is sand used in multimedia filters?

• It is cheaper than other media

• It provides finer filtration

• It is used for decoration

• It is lighter than anthracite

What is the role of valve A in multimedia filters?

• Service inlet

• Backwash water inlet

• Service outlet

• Drain valve

At what flow rate do conventional pressure rapid filters operate?

• 9 to 10 GPM per square foot

• 1 to 2 GPM per square foot

• 6 to 8 GPM per square foot

• 3 to 5 GPM per square foot

What triggers the need for a backwash in a multimedia filter?

• A decrease in water temperature

• A change in water color

• An increase in water flow rate

• A high pressure drop across the bed

What is the recommended backwash flow rate for multimedia filters?

• 5 to 7 gallons per minute per square foot

• 12 to 15 gallons per minute per square foot

• 16 to 18 gallons per minute per square foot

• 8 to 10 gallons per minute per square foot

What should be checked if the differential pressure remains high after backwashing?

• The size of the filter

• The temperature of the water

• The water quality used in backwashing

• The color of the filter media

How often should the media in a multimedia filter be replaced?

• Every 1 to 2 years

• Every 3 to 4 years

• Every 8 to 10 years

• Every 5 to 7 years

What is the first step in the backwash process?

• Air scouring

• Backwash flow with backwash pump

• Pre-service rinse

• Drain the existing water from the MMF