WEF Discussions — Now on LinkedIn!

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Sand filters Flow rate peak cals.....
Posted: Sunday, February 14, 2010 2:20 AM
Joined: 2/14/2010
Posts: 1


Hi members ,


Please find below Sand filters data , i would like to know how did the designer  arrived the Flow rate ( peak) value


No of Filters




Rapid gravity sand filters , rectangular , layered media placed above lateral outlet tubes


Design flow




Ames crosta Babcock


Influent quality

25 mg/lit BOD /l , 30 mgSS/l , 5 mgNH3N/i


Effluent quality

Effluent quality 10 mgBOD/l , 10 mg SS/l ( at peak flow)


Filter area


M2 each

Flow rate ( Peak)



Bed size

9 X 5.8 m

Each bed spilt into 2

Water level



Filter media

Grade ( 1/10-1/4” , 3/8 & 1/2 TO 3 /4 “ )


Posted: Tuesday, February 23, 2010 12:45 AM

 Hi forum members ,

Volume of excess Sludge = (Q x BODin x Yobs x BODRE) ÷ MLSS                                                

Q      Influent flowrate      m3/d
BODinInfluent BODKg/m3
Yobs      Observed yield coeficient %
BODRE BOD removal efficiency %
MLSS      Mixed liquor suspended solidsKg/m3

I was told that the above equation can be used to determine the sludge wasting for a Activated sludge plant.

I would like to know the following

Is it applicable to all types of ASP plants
The source of this equation ( any books references etc.,)

OR is there any other method available

can any one share views with me