Activated Carbon Backwash Water
Activated Carbon Backwash Water
(OP)
This has probably been done before but I couldn't find anything.
I hope someone can help. I have a fairly remote WTW site which needs to be treated for pesticides.
The site has no discharge points and we would therefore need to tanker away any waste from GAC backwashing and regeneration.
There is a small river near to the site which has been investigated as a potential discharge point however I have now had several different opinions on the possibilty of discharging the Activated Carbon backwash water to this point.
What I am wondering is how difficult is it to settle out activated carbon backwash water, do you get carbon fines in the backwash water?
I know a lot of it will be site specific so I'm really after peoples experiences.
We would have a backwash volume of 75m3 for each backwash.
Can anyone offer any advice please?
I hope someone can help. I have a fairly remote WTW site which needs to be treated for pesticides.
The site has no discharge points and we would therefore need to tanker away any waste from GAC backwashing and regeneration.
There is a small river near to the site which has been investigated as a potential discharge point however I have now had several different opinions on the possibilty of discharging the Activated Carbon backwash water to this point.
What I am wondering is how difficult is it to settle out activated carbon backwash water, do you get carbon fines in the backwash water?
I know a lot of it will be site specific so I'm really after peoples experiences.
We would have a backwash volume of 75m3 for each backwash.
Can anyone offer any advice please?





RE: Activated Carbon Backwash Water
I don't understand why you are trying to backwash the activated carbon as the backwash water may contain some of the contaminants that you are trying to adsorb onto the carbon.
Usually, when you are using activated carbon for an application like you are describing, the vessel is almost completely filled with carbon and you will not be backwashing the activated carbon at all.
Activated carbon is typically sluiced out into a truck when you want to change-out the carbon. Alternatively, you can change-out the complete activated carbon vessel. The vessels can be transported while the vessels are full of activated carbon. It is also common to operate activated carbon vessels in series with working and polishing vessels.
If you have any filterable materials in your water stream, you probably should consider filtering prior to the carbon filters to prolong the carbon filter bed life.
RE: Activated Carbon Backwash Water
Thank you for the response
RE: Activated Carbon Backwash Water
My 2ยข for what it is worth.
RE: Activated Carbon Backwash Water
For a routine taste and odor activated carbon installation, backwashing would commonly be done once per week.
For a remediation application where you are trying to remove chemical contamination, backwashing may not be a routine operation. When you trying to remove a chemical contaminant, you are generally not allowed to discharge the contaminants with the backwash water.
If you have a small volume system, consider the use of serviced adsorption systems.
Carbon fine removal is simple. You need to collect the backwash volume in a holding tank and allow the fines to settle. The fines should settle out of the backwash water in an hour or so. This is commonly done in a conical bottom tank as cub3bead suggested. Alternately, you can sidestream filter out the fines (as cub3bead also suggested) and then discharge to waste the contents of the backwash holding tank.
RE: Activated Carbon Backwash Water