Design the structural components of a dual-media rapid filter for the city of Apple Vall...

Design the structural components of a dual-media rapid filter for the city of Apple Valley. The maximum day flow rate is 45,000 m³/d. The design criteria and media analyses are given below. Assume a 525 mm diameter pipe from the gullet is to carry the wash water at a velocity of 1.5 m/s. Verify that the sand meets the GLUMRB recommendations for E and U. Adjust the grain size distribution if the sand does not meet the specification. Also verify that largest grain size anthracite coal will have the same approximate settling velocity as the finest sand grain size.

The following is to be provided to complete this portion of the filter design:

Clean bed headloss

Backwash velocity

Depth of expanded bed

Number of filter beds

Area of an individual filter bed

Plan dimensions

Backwash trough layout

Maximum backwash water trough flow rate

Backwash trough dimensions

Backwash trough weir elevation above undisturbed bed

Gullet dimensions

Backwash water volume

Backwash tank volume

Maximum allowable filtration headloss

Depth of filter box

Backwash tank low water elevation