Ammonia contamination from Pentek GAC-20 filter

[Gary Meyer]

Hello

We recently purchased, from you, and installed a GAC-20 filter upstream from our laboratory RO pretreatment system. Immediately we started to find ammonia in the output. Troubleshooting the system led us back to the GAC filter.

We hoped the contamination would decrease with time, but that does not seem to be the case. We are finding levels in excess of 1 ppm.

This level may not be a concern for homeowners (especially if they do not know it is there), but as a water treatment plant laboratory that critically analyzes for ammonia hourly, it is.

So...

Are you aware of this contamination?

Is it within your specifications, or is this unit defective?

If it is within your specifications, can you recommend a higher quality replacement? FYI this fitler (GAC-20) is a direct replacement of the previous unit.

[Alex]

I have not heard of this issue before,and is not in any filter specifications. How long has it been since your filter was replaced?

Do you have a water analysis report of the water that is being filtered?

I am interested in seeing the free, combined, and total ammonia in the filter influent.

Do you have the model number of the previous unit?

[Gary Meyer]

We installed this GAC-20 on 12/16/13. I would expect we have passed in the neighborhood of 100 - 200 gallons through the filter since installation. The level of ammona has reduced, but it is still above 0.5 ppm

We have a pretty good idea what is in the water... we are a water plant and analyze the water we are producing 24/7. What would you like to know? Probably the most important info pertaining to this: our product water ammonia level is less than 0.10 ppm. That is what is feeding the lab RO system.

This cartridge protects the RO membrane from chlorine. The RO is a pretreatment for our lab pure water unit.

We do not analyze for total ammonia. We critically monitor the combined as we are a chloramination system. The combined is primarily monochloramine and it is in the 3.5 ppm range.

The previous model was also a Pentek GAC-20. It was in service for 9 months. There was no ammonia (well... <0.01 ppm) in the RO stream when using that filter, but we are on a routine maintenance schedule and we replace them between 6 and 12 months.

[Alex]

I have forwarded this information to technical support at Pentek which is typically very helpful, and I am curious what could cause this to happen.

I will let you know as soon as I hear back. Thanks,

Alex