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Multimedia Filters Design

Multimedia Filters Design

Multimedia Filters Design

(OP)
I need some guidelines in regards to Multimedia Filters bed dephts. Specially on the gravel support layer.

I have found on my system that there´s media leaking downstream and my first guess is that the gravel layer is too short.

By the way, is there any difference between layers depth when using air for BW?  

RE: Multimedia Filters Design

How many stages or media types in your filter? Anthracite, courser sand, finer sand, gravel?
Are you doing a collapsed pulse (combined water/air) BW or individual aire then water stages? If your leaking media, where is it appearing? It could be beign lost during backwash or else through damaged nozzels in the floor.

RE: Multimedia Filters Design

The design of the gravel support will depend somewhat on the design of the underdrain.

You should have from 4 to 6 layers of gravel. A four layer filter should have gravel gradings of 0.7-1.4 mm, 2-4 mm, 6-12 mm, and 18-36 mm. A six layer filter should have gravel gradings of 0.6-1.1 mm, 1.2-2.4 mm, 2.4-4.8mm, 4.8-10mm, 10-20 mm, and 20-40 mm.

The finer gravels should be 3-Inches in depth for each gravel gradation. The coarser gravels should be 4-5-Inches in depth for each gravel gradation. The overall depth of the support gravel should be approximately 0.3-0.45 m (12-18-Inches).

http://www.who.int/water_sanitation_health/publications/ssf4.pdf

Verify the gravel support requirements with the manufacturer of your filter.


 

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