GAC Backwash intervals

[Umaagon]

In a surface source water treatment facility. Using a GAC adsorber for removals of organics. Is it critical to backwash in a routine time frame? Or is it only important to backwash based off of differential pressure drop? The GAC we use, can handle 700 GPM. However during our slow time of the year we may only be running 200 GPM at most. So we may never see a critical amount of pressure differential. So I'm wondering if there should be a weekly or bi weekly routine backwash to prevent the growth of microorganisms despite not having a high amount of pressure drop.

 

[bimr]

Periodic backwashing is necessary to keep the carbon bed in good shape. Excessive mixing of the carbon should be avoided as the contaminants will migrate through the carbon bed leading to premature breakthrough of contaminants.

 

[pierreick]

Hi,
Agree with bimr , regular and periodic backwash will prevent accumulation of contaminants and also prevent the risk of channeling within the bed.
Preventive is better than curative for this type of application.
Make sure you have a way to dispose the contaminant and the AC. In some countries like China the use of AC is very expensive to dispose.
Pierre