Flow to filter is stopped |
Backwash is started and bed fluidizes |
Backwash continues as long as required to flush
particles blocking flow from filter |
Particles blocking flow from filter are now in
water above media |
Backwash stops. Particles coated with biofilm settle into original pre-backwash position - on the
surface of the media |
Water containing suspended particles is discharged
|
State of filter after backwash
and discharge complete. Note that the particles with
biofilm are at the surface |
Filtration
resumes |