Multimedia Filter Operations and Maintenance

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