Their new permit limits their ammonia discharge to <1 mg/L ammonia year round.  Since the camp is remotely located and does not have an operator, we are considering adding a wetland to remove the last bits of ammona.

Does anyone out there have any data that would help us justify our process selection to the State?  Does anyone operate a wetland that has an ammonia limit?

Thank you!

A different design would use a true wetland. This would use a variety of different kinds of plants, and depend more on lateral movement through the system. There are several variations. One, I've seen at a summer camp, seems to work pretty well, but I'd have to dig up file material to say anything about ammonia treatment. Several other systems, tried at POTWs, have been less effective.

Another option you may want to consider, if there is sufficient area available, is surface land application. I have a number of camps using slow-rate irrigation systems with success. Whether you go with slow-rate irrigation or overland flow will depend on factors such as soil types, slopes, vegetation, and so on. There are a number of books and an EPA manual you can use for more information.

Hope this all helps.

We are considering a subsurface flow wetland with gravel fill.  Anything else would just freeze into a big block of ice out here in the high Rocky Mountains.

Suggest adding a nitrification polishing step to your RGF in the form of additional Orenco's Avantex fabric filter pods. These pods are achieving <1 mg/l summer ammonia at Hebo, Oregon with a 5:1 recycle ratio. Taking the effluent from your RGF to multiple passes over some Orenco pods should complete the nitrification and would be more controllable than a gravel bed.    

Orenco design staff in Roseburg, Oregon have these data.  They may also have further suggestions for your consideration. 

Crazy, yes?  We wouldn't want to harm the fish that might live in that stream when it's flowing. 

The funny thing is that during the months of the year when there is flow in the stream, we can discharge up to 5 mg/L of ammonia.  However, the annual average concentration is still 1 mg/L which essentially holds us to the lower limit year round.

Getting back to your ammonia problem: the claims for the reed bed systems are that they work at 10,000 ft. elevations in places like Peru. I'm still waiting for proof that they work in the middle of winter around here, but if you are interested, you might want to contact Dr. Ronald LaVigne for more info.

Does anyone have any experience with this technology?

I saw a novel idea for improving the ammonia conversion in a recirculating sand filter.  They hooked up a small centrifugal blower and blew air into the bottom of the filter through the underdrain system.  They have not tested for ammonia removal because it is not in their permit, so I cannot say if it works.  I see the logic to it, they should have enough retention time to grow nitrifiers and the filter should have plenty of biomass.  If the limiting factor in nitrification in a recirculaiton sand filter is oxygen, it might work.

Another idea I know  can work is drip irrigation, just eleimiante that discharge!