cubm hr-1 m2
| operating home |
Operating guidelines for AFM filters |
| Applications |
|
Run phase water flow-rate
cubm hr-1 m2 |
Air
purge all filters at 95 cubm/hr at no more than 0.4 bar pressure |
Back-wash water flow
cubm hr-1 m2
for grade 1 AFM |
Back-wash water flow duration
minutes |
(2)Back-wash frequency |
|
Drinking water |
optimum |
5 - 10
|
2- 4 minutes |
50 - 60 |
4 - 8
|
1 to 2 times per day |
| maximum |
10 - 15
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Swimming pool |
optimum |
10 - 15
|
2 - 4 minutes |
50- 60 |
4 - 8 |
1 times per week or every second week |
| maximum |
15 - 30
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Sewage treatment and industrial effluent |
optimum |
1 -5 |
4 to 8 minutes |
55 - 65 |
2 - 4 |
4 to 8 times per day |
| maximum |
5 - 15
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| |
4 - 8 |
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River, lake and sea water
| optimum |
5 - 10 |
4 to 8 minutes |
50 - 60 |
4 - 8 |
2 to 4 times per day |
| maximum |
10 - 30 |
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| Aquaculture |
optimum |
5 to 15 |
4 to 8 minutes |
50 - 60 |
4 - 8 |
2 to 4 times per day |
| |
maximum |
10 to 30 |
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| Public aquariums |
optimum |
5 to 15 |
3 to 6 minutes |
50 - 60 |
4 - 8 |
1 times per week or every second week |
| |
maximum |
15 to 30 |
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| Landfill Leachate |
optimum |
1 to 5 |
8 minutes |
55 - 65 |
4-8 |
6 times per day
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Notes - Bed expansion should be around 150mm for a 1m deep bed.
- In some cases such as the removal of iron and manganese from water supplies, it can actually be more effective to use a short back-flush and allow retained metals and solids to stay in the bed. The retained solids can in some cases improve the performance of the filter. For example, if there are diatoms ( algae) in the water, the diatoms will improve filter performance, but the pressure head will also increase. For critical applications such as swimming pools and drinking water, the back-flush should continue until the water runs clear. On average AFM will remove around 50% more solids from the water than a sand filter, so the back-flush times end up being similar, but almost twice as much solids are removed from the water.
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Air purge for 2 to 8 minutes prior to back-flushing is recommended for all applications, however unlike sand air scouring is not essential for AFM , although it does improve performance.
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