DIY Sulfur Denitrator

[siskiou]

My tank is now down to 5ppm nitrates and coming down fast.
I'm running it almost fully open now and am wondering what to do when the tank reaches 0 nitrates.
The feed pump on the reactor is fairly small, so it doesn't push through a huge amount of water.
Should I use a stronger feed pump, or go to less sulphur in the reactor?
Or will the bacteria adjust if I just leave it running as is?

BTW, would this type of reactor work for a freshwater tank, too?
My daughter is always struggling with nitrates on her 29G freshwater tank.

 

[EnderG60]

UPDATE

welp if my nitrates are not 0, they are pretty close to it!

Im still not getting very much gas to let off at the top though...not sure if I should be worried about that. And do I keep increasing the flow, im pretty sure im over 1 liter per hour now(since I only have about 1 liter, or half of that 3.5lb bag of media running)

 

[adnup]

5.4L per hour and still smells - NO3 zero out of SR

Increased to 7.5lph

I calculated that I have 2.8L of LSM in my SR

 

[wizsmaster]

Hey djfrankie,

I'm running about 2.88 L/hour (48 ML /Min) through my Korallin S-4002 on a 500g system. Just bumped the flow up a bit about 6 hours ago - will test in another 36h if we're still putting out 0 nitrates.
What do you think i should be flowing around? The 4002 ships with 20lbs of media .. i think it was 15 sulfur/5 ca media.


Take care,

marco

 

[wizsmaster]

how many of you guys monitor the ORP within the reactor? I had read some posts about monitoring ORP, and keeping it around =160? or was it -200? cannot remember, or find the posts/thread where i read this.

 

[rolyguy7]

I've got one of these sulfur denitrators built but am having a bit of a problem getting it dialed in. It's been running for 4 days now but I'm still seeing some nitrates on the effluent. If I speed up the drip rate to a slow flow the nitrates out of the effluent are much higher than the tanks. If I speed up the drip rate to a fast flow the nitrates on the effluent are about the same as the tanks. If I lower it to 4/5 dps the nitrates on the effluent are about the same as the tanks. Anyone seen similar behavior on their system? Also since I've added the denitrator my tanks PH has dropped from 8.0 to 7.7. My dkh is at around 10dkh. Can't seem to figure out why my PH has dropped or how to raise it back up. Any help would be great.


FYI... My tanks nitrates are around 30ppm. The effluent nitrates on slow flow got up to 50-100ppm reading on salifert test kit.

Thanks...

 

[zachtos]

<a href=showthread.php?s=&postid=12324799#post12324799 target=_blank>Originally posted</a> by rolyguy7
I've got one of these sulfur denitrators built but am having a bit of a problem getting it dialed in. It's been running for 4 days now but I'm still seeing some nitrates on the effluent. If I speed up the drip rate to a slow flow the nitrates out of the effluent are much higher than the tanks. If I speed up the drip rate to a fast flow the nitrates on the effluent are about the same as the tanks. If I lower it to 4/5 dps the nitrates on the effluent are about the same as the tanks. Anyone seen similar behavior on their system? Also since I've added the denitrator my tanks PH has dropped from 8.0 to 7.7. My dkh is at around 10dkh. Can't seem to figure out why my PH has dropped or how to raise it back up. Any help would be great.


FYI... My tanks nitrates are around 30ppm. The effluent nitrates on slow flow got up to 50-100ppm reading on salifert test kit.

Thanks...

Only safe way to raise ph that i've found is to lower the drip rate on your calcium reactor, and start dosing heavily on limewater/kalkwasser. That solved the problem for me for now.

 

[rolyguy7]

So does anyone have an idea why my nitrates exiting the sulfur denitrator are above 50ppm while the tanks nitrates read 25-30ppm? Should I slow or speed up the drip rate?

Thanks...

 

[IowaReef]

I would suggest slowing it. Only increase it once it is at Zero. The good bacteria is still getting established. You may not want that going into your tank yet.

But I am still just learning...

 

[Paul_PSU]

Thats correct. keep it at 1 drop/sec until zero Nitrates from the effluent. Once they are Zero you can bump it up to 2 drops/sec and then measeure effluent for Zero again and so on and so on.

 

[rolyguy7]

Now is it just me or does this not make any sense at all? How can the output be higher in nitrates than the input? If there's not enough bacteria yet shouldn't the output be basically the same or slightly lower than the input? Anyone know why the nitrates exiting the denitrator end up higher than the tank?

Thanks...

 

[1scienceguy]

Aerobic bacteria are processing the ammonia and nitrites.

 

[rolyguy7]

My tank reads 0 ammonia and 0 nitrites. I'd like to know how exactly this works if anyone knows and can fill in the blanks.

It is my understanding from what I've read so far that the bacteria that will be living in the sulfur denitrator can live in both aerobic and anoxic conditions. It is in anoxic conditions that the bacteria ends up removing nitrates. Since the bacteria needs oxygen it reduces nitrate to liberate oxygen to survive. The part I don't understand is why the nitrates are exiting so high while dialing in the denitrator? Is the bacteria producing nitrates during the cycling period while its living in aerobic conditions (Which would explain the high nitrate output at first) but once cycled the tables turn and they commence to use up the tanks nitrates to release oxygen while in anoxic conditions? I'm new at working with sulfur denitrators. If anyone with more knowledge can chime in I'd appreciate it. Please feel free to correct me if I'm wrong.

Here's one of the articles I read.

http://www.aquariumfish.com/aquariumfish/detail.aspx?aid=17592&cid=3793&search=

Thanks...

 

[TulsaReefer]

<a href=showthread.php?s=&postid=12326355#post12326355 target=_blank>Originally posted</a> by rolyguy7
Now is it just me or does this not make any sense at all? How can the output be higher in nitrates than the input? If there's not enough bacteria yet shouldn't the output be basically the same or slightly lower than the input? Anyone know why the nitrates exiting the denitrator end up higher than the tank?

Thanks...

Nitrite will throw many (if not most) Nitrate test kits off if it is present in the sample. It's most likely that your Nitrates aren't really higher than your tank, it's that your getting partial Nitrate reduction, and it's breaking down into Nitrite, which will often show up on a Nitrate test as much higher than the actual Nitrate level is. In my Red Sea test kit this is explained, and a chart is included to help calculate the actual values if Nitrite is present. Once the bacteria get colonized they will fully consume the Nitrate and you won't get any more Nitrite.

 

[rolyguy7]

Thanks TulsaReefer, that makes sense. I use to have a seachem test kit that did both and showed you how to figure out the nitrates by removing the nitrite results. I think I'll go pick one of those up this afternoon since I ran out about a month or two ago. I've been using the salifert nitrate test kit and I think like you said it's reading both nitrite and nitrate. Anyone have any experience with salifert nitrate test kits? Any ideas on how to determine true nitrates with this test kit?

Thanks...

 

[TulsaReefer]

Try measuring the effluent for Nitrite, if it's present it's likely that it's what's throwing off your Nitrate test. I also used a Salifert when I was breaking in my unit last year but didn't ever notice the effluent higher than the tank, but then on Salifert once you get above 60 to 80 it's hard to tell anyway (looks like red kool-aid). And as my tank was around 60 to 80 at the time... And I never did buy a Nitrite test kit to check things, I just took it slow and broke the unit in. At 1 drop per second my unit took about 2 weeks to hit zero on the effluent, and it usually takes longer for tanks with higher nitrate levels. This makes sense as it takes longer to get the bacteria up to a level that allows them to fully consume the nitrate level coming in.

 

[rolyguy7]

I have a salifert nitrite test kit at home as well. I'll go ahead and test the nitrites on the effluent when I get home. I called the house and had a family member turn down the drip rate to 1-2 drips per second. Hopefully the denitrator will cycle soon.

Thanks....

 

[rolyguy7]

I found an interesting read about the bacteria for those like me that are curious on learning more. Here's a description from the article:

Description of Thiobacillus denitrificans (ex Beijerinck
1904a) nom. rev. Kelly and Harrison (1989a)
Thiobacillus denitri®cans (de.ni.tri«®.cans. M.L. v.
denitri®co denitrify ; M.L. part. adj. denitri®cans
denitrifying).
Short rods 0±5¬1±0±3±0 lm in size. May be motile by
means of a polar ¯agellum. Clear or weakly opalescent
colonies are grown anaerobically on thiosulfate}
nitrate agar, which upon ageing may become white
with sulfur. Growth in anaerobic stab- or roll culture
results in agar splitting due to production of nitrogen
gas. Facultatively anaerobic. Grows as an aerobic
chemolithoautotroph on thiosulfate, tetrathionate and
thiocyanate. Grows as an anaerobic chemolithoautotroph
on thiosulfate, tetrathionate, thiocyanate,
sul®de or elemental sulfur by using nitrate, nitrite or
nitrous oxide as terminal respiratory oxidants; transient
formation and consumption of nitric oxide has
been observed. Oxidizes sulfur, sul®de, thiosulfate,
tetrathionate, sul®te and thiocyanate. Batch cultures
can be grown in completely ®lled bottles, producing
vigorous nitrogen evolution. Chemostat culture can be
switched easily and repeatedly between aerobic and
anaerobic growth modes, with adaptation involving
derepression of nitrate and nitrite reductase synthesis.
Ammonium salts and, in some strains at least, nitrate
are used as nitrogen sources. Obligately chemolithotrophic
and autotrophic. Optimum temperature
28±32 °C. Optimum pH 6±8±7±4. Found in soil, mud,
freshwater- and marine sediments and also in domestic
sewage and industrial waste-treatment lagoons and digestion tanks, especially under anoxic conditions.
Probably very widely distributed. The G_C content
of the DNA is 63 mol% (Bd, Tm). The type strain is
NCIMB 9548T. This is the strain (AB7) deposited by
Hutchinson et al. (1967), which is also available as
ATCC 23644T and JCM 3870T. A member of the b-
Proteobacteria.

Article link:

http://ijs.sgmjournals.org/cgi/reprint/50/2/547.pdf

 

[saltydog64]

<a href=showthread.php?s=&postid=12294031#post12294031 target=_blank>Originally posted</a> by siskiou
Another update!

I've had the unit running on the tank for about 10 days now.
Currently at about 6 d/s, though getting hard to count the drops.
I keep cranking it up a bit each day after testing the effluent for nitrates, but it's stayed at 0 so far.
Nitrates in the tank are down to about 20ppm from the previous 40-45ppm and I'm very happy with the results!
Thanks again for sharing the design, djfrankie!

I've started to feed a little more generously again, after feeding the bare minimum for several months, while trying to get the nitrates down with water changes.

I keep doing regular 20% wc every two to three weeks, but I never was able to get the nitrates down in this tank before.
My other tank (60G cube) with only one fish is at 0 nitrates without a denitrator.

sis..............Way to go girl,:rollface: :rollface: . Excellant job and keep us informed OK ?? I'm back on the course now and daliy updates are.... well slow to come, but cont. sucessto you.

Dick

 

[Black71gp]

man.. i cant get mine to 0.. they are sitting around 1 or so... coming out of the denitrator.. i am getting a bit of gas build up at the top.... no smell though... its been at like 1 for a while... three days now...