OK, this got started in another thread, here:
http://www.monsterfishkeepers.com/forums/showthread.php?t=136329
and kinda hijacked the originators post before petering out. I'd like to re-open the discussion, because there are some unanswered questions. A decent summary of the technology can be found here:
http://mars.reefkeepers.net/USHomePage/USArticles/SulphurDenitrator.htm
I'm making my 200gal tank the guinea pig, and I plan to build one of these lovelies with some 6" ABS drainage pipe, a little powerhead, some sulfur pellets, and some crushed oyster shell.
Now, the chemical details are a bit hazy, but I'm not super interested in further clarifying them, I'm mostly just trying to figure out the most effective, maintenance friendly way to do this, and hopefully be able to share with all you guys. Small sulfur denitrators go for around $500, and as far as I can tell, all you get is some sulfur, a pipe, and a pump.
There are two schools of thought on the general application here, and I'm stuck between them.
1) Make two reactors, one with sulfur pellets for the autotrophic bacteria to do their thing, reducing nitrates to nitrogen gas, and sulfates, along with some CO2, and H+ Ions, making an acidic solution leaving reactor 1. Then, run through a second reactor filled with calcium Carbonate (crushed coral or oyster shells) to bring the pH back up, and precipitate out some of the dissolved sulfates. This is the type of system typical of the aquarium denitrators. The advantage of this system is that you can maintain the reactors separately, topping up or completely cleaning out the CaCO3 reactor without touching the sulfur reactor. This is also a nice system, because if your nitrate reactor spits out any NitrIte in the effluent (nitrate that it never really finished processing) it gets run through your crushed limestone, where presumably some nitrifying bacteria exist... so it gets turned back to nitrate before re-entering the fish habitat.
2) Make a single reactor, Sulfur pellets mixed with a source of CaCO3, like limestone, marble chips, crushed coral, crushed oyster, etc. This is widely used in large scale wastewater treatment, and is known as the SLAD (Sulfur Limestone Autotrophic Denitrification) Process. This is nice and neat, with only one reactor. It also has the advantage that as the Nitrate is consumed, and acid is produced, the CaCO3 is dissolved, keeping the pH up, and lots of available alkalinity for more nitrate reduction. The disadvantage is that if you put too much or too little CaCO3 in the reactor, and it gets used up faster or slower than the sulfur, you have to take the whole thing out, dump it out, wash it, sort it, remix it, and put it all back together for your semiannual maintenance.
I have more to write on this, but that's enough for one post. Let the discussion begin
http://www.monsterfishkeepers.com/forums/showthread.php?t=136329
and kinda hijacked the originators post before petering out. I'd like to re-open the discussion, because there are some unanswered questions. A decent summary of the technology can be found here:
http://mars.reefkeepers.net/USHomePage/USArticles/SulphurDenitrator.htm
I'm making my 200gal tank the guinea pig, and I plan to build one of these lovelies with some 6" ABS drainage pipe, a little powerhead, some sulfur pellets, and some crushed oyster shell.
Now, the chemical details are a bit hazy, but I'm not super interested in further clarifying them, I'm mostly just trying to figure out the most effective, maintenance friendly way to do this, and hopefully be able to share with all you guys. Small sulfur denitrators go for around $500, and as far as I can tell, all you get is some sulfur, a pipe, and a pump.
There are two schools of thought on the general application here, and I'm stuck between them.
1) Make two reactors, one with sulfur pellets for the autotrophic bacteria to do their thing, reducing nitrates to nitrogen gas, and sulfates, along with some CO2, and H+ Ions, making an acidic solution leaving reactor 1. Then, run through a second reactor filled with calcium Carbonate (crushed coral or oyster shells) to bring the pH back up, and precipitate out some of the dissolved sulfates. This is the type of system typical of the aquarium denitrators. The advantage of this system is that you can maintain the reactors separately, topping up or completely cleaning out the CaCO3 reactor without touching the sulfur reactor. This is also a nice system, because if your nitrate reactor spits out any NitrIte in the effluent (nitrate that it never really finished processing) it gets run through your crushed limestone, where presumably some nitrifying bacteria exist... so it gets turned back to nitrate before re-entering the fish habitat.
2) Make a single reactor, Sulfur pellets mixed with a source of CaCO3, like limestone, marble chips, crushed coral, crushed oyster, etc. This is widely used in large scale wastewater treatment, and is known as the SLAD (Sulfur Limestone Autotrophic Denitrification) Process. This is nice and neat, with only one reactor. It also has the advantage that as the Nitrate is consumed, and acid is produced, the CaCO3 is dissolved, keeping the pH up, and lots of available alkalinity for more nitrate reduction. The disadvantage is that if you put too much or too little CaCO3 in the reactor, and it gets used up faster or slower than the sulfur, you have to take the whole thing out, dump it out, wash it, sort it, remix it, and put it all back together for your semiannual maintenance.
I have more to write on this, but that's enough for one post. Let the discussion begin
