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AFM
Active Filter Media
replaces sand in all types of sand filter
Environmental & sustainable water treatment to save the planet

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operating home

Operating guidelines for AFM filters

Applications   water flowrate

cubm hr-1 m2

(1)Back-flush flowrate

cubm hr-1 m2

Back-flush duration

 minutes

(2)Backflush  frequency
drinking water optimum 5 - 10

Back wash flowrate flowrate should be between 40 and 45 cubm/hr/squm This flowrate applies to sand as well as AFM and is required to fluidise the bed by up to 15%.  If you do not fluidise the media the filter will not be properly cleaned

4 - 8 1 to 2 times per day
maximum 10 - 15    
swimming pool optimum 10 - 15 4 - 8 1  times per week or every second  week
maximum 15 - 30    
sewage treatment and industrial effluent optimum 1 -5 2 - 4 4 to 8 times per day
maximum 5 - 15 4 - 8  
river, lake and sea water

 

optimum 5 - 10 4 - 8 2 to 4 times per day
maximum 10 - 30    
Aquaculture optimum 5 to 15 4 - 8 2 to 4 times per day
  maximum 10 to 30    
Public aquariums optimum 5 to 15 4 - 8 1  times per week or every second  week
  maximum 15 to 30    
Landfill Leachate optimum 1 to 5 4-8 6 times per day

Notes

  1. Bed expansion should be around 150mm for a 1m deep bed.
  2. 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.
  3. Air scouring for 5 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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