fluidized bed reactor to reduce nitrates?

[Sulcata102]

i read on a forum that using a fluidized bed reactor set so the sand barely moves will reduce nitrates. anyone have any thought as to how effective it would be? has anyone had any success in doing so? would anything else have to be done to make it work? i have a few kicking around that i used to use. I took them off cause they were nitrate producers but i always ran them up at normal flow. It would be nice to have a use for them again.

[bertoni]

That might work, but I'd be cautious. If very much organic debris made it to the sand, it might become a mess.

[downbeach]

You might be better served to try a carbon source, i.e. vinegar, vodka, or bio-pellets in a reactor.

[daido]

That is an example of a nitrate reactor. The slow water movment makes sure that the unaerobic bacteria in the reactor won't die from high oxygen exposure. The flow needs to be a few drops every 10 seconds. Carbon dosing is used to feed aerobic bacteria, that is a different kind of bacteria comparing to those you will find in the reactor you are planning to build.

[Sulcata102]

thanks everyone.

[Alex]

The best way I used to remove nitrates was to make a reactor with PVC and airline tubing. I used 4" PVC about 3'to4' long with drilled end caps for air line tubing. Get 100' of airline tubing this will go into the PVC. When I originally tried this I coiled the airline tubing into the PVC but it just became a giant mess with kinks in the tubing everywhere which prevented water flow. I then cut a board to fit into the 4" PVC and notched out the ends so the air line tubing could wrap long ways on the board. Be careful to wrap the tubing lightly to avoid pinched tubing. Then slide the board in the PVC and place the end caps on to block the light. Now put a low flow of water through the airline tubing 1 drop/second or less. This will provide a dark oxygen free area and bed for the anaerobic bacteria to grow that consume nitrates. I used to use fluidized bed filters a long time ago in a FO tank and my nitrates were through the roof. After I got this reactor going I dropped them down to low levels in a couple of months.

[uny2bld]

The best way I used to remove nitrates was to make a reactor with PVC and airline tubing. I used 4" PVC about 3'to4' long with drilled end caps for air line tubing. Get 100' of airline tubing this will go into the PVC. When I originally tried this I coiled the airline tubing into the PVC but it just became a giant mess with kinks in the tubing everywhere which prevented water flow. I then cut a board to fit into the 4" PVC and notched out the ends so the air line tubing could wrap long ways on the board. Be careful to wrap the tubing lightly to avoid pinched tubing. Then slide the board in the PVC and place the end caps on to block the light. Now put a low flow of water through the airline tubing 1 drop/second or less. This will provide a dark oxygen free area and bed for the anaerobic bacteria to grow that consume nitrates. I used to use fluidized bed filters a long time ago in a FO tank and my nitrates were through the roof. After I got this reactor going I dropped them down to low levels in a couple of months.

I was thinking of doing a fluidized bed filter as well out of a 55 gallon drum. I know that they produce a ton of nitrates after converting nitrites and phosphates but isn't there a way to deal with the nitrates after going through the sand filter?

I read somewhere that for best results, you want the water to slowly pass through the sand so the water has the longest exposure time to the sand and I think I could achieve that with a 55 gal drum...

I'm having a hard time finding good info. I see these on hobbiest systems as well as a ton of commercial applications so I know they work but can't find good info as to how they work...

Anyone?

[uny2bld]

I forgot to mention that I was thinking of adding macro and mangroves as well as liverock to the top of the 55gal drum. The drum would lead back into the pond that this sytem is on...

[bertoni]

The mangroves probably will have only a small effect on the nitrate level, but growing and harvesting a macroalga can do a lot. Carbon dosing can help, too, and often is cheaper.

[tmz]

The bacteria performing denitrification are facultative heterotrophs. They live in the presence of oxygen and without it turn to nitrate for it. Exposure to oxygen won't kill them.