DIY Sulfur Denitrator

[Belgian Anthias]

I am up to 4 or 5 drops per second with 0 nitrate effluent. Tank nitrates are still climbing. Where do I go from here??
Approximately 175 gallon volume. Using 1 full gallon of l.s.m. sulfur and 1 full gallon of a.r.m. media.

What is your nitrate level for the moment?
5 drops/sec = +- 1,5lH

Increase the flow gradually. If after a few days effluent is not 0 or nitrite is detected decrease a little. Flow should be +- 2l/h depending the nitrate level. if there is enough sulfur depends of the daily nitrate production to remove and if the desired level can be reached and maintained. For the nitrate level to decrease more than the daily production has to be removed daily.
When the level starts to decrease flow has to be adjusted to the nitrate level to keep enough de-nitrifying capacity.
At the desired level flow may have to be 5l/h and more.

 

[BROTHERSPIZZERIA]

Nitrate was between 30 and 40. I did a 50 gallon water change so should be 30 or less now.

 

[Belgian Anthias]

Nitrate was between 30 and 40. I did a 50 gallon water change so should be 30 or less now.

30 mg/l, the reactor is removing 1,5l /h x 24h x 30 mg = +- 1080 mg nitrate daily. For a 660l system this is +-1.5ppm daily. As the level is still increasing this means that the daily production is more than 1.5 ppm daily. This is a lot. This means also that 1 gal of sulfur will not be sufficient to lower the level to an acceptable level of 2 ppm because flow has to increase to 540 litre daily to remove 1080 mg and we know this will not be enough.

 

[BROTHERSPIZZERIA]

So am I safe to assume I can just add another gallon of sulfur media and that should be sufficient?

 

[Belgian Anthias]

So am I safe to assume I can just add another gallon of sulfur media and that should be sufficient?

The quantity sulfur depends on the daily to remove nitrate. As the level is not descending yet we still can not estimate the daily to remove nitrate. It is not possible to say for the moment if 2 gal will be enough. I would also try to find out the reason why the level increases more than 1 ppm a day. If the reason is known or/ and can not be corrected 2 gal will be a minimum to bring the level to <2ppm and keep it there. While reducing the nitrate level it is important to measure the nitrate level regularly.
Increase the flow gradually until nitrate level is descending and/or the max capacity of the reactor is reached.( probably between 1 and 2 gal/h) Once the level is decending and flow is not corrected the reactor will be limited by the nitrate entering the reactor and the level will stop descending when the daily to remove quantity of nitrate can not be removed any more. At that point the daily produced nitrate can be estimated. Do not decrease the flow at that point. Flow should increase to bring more nitrate to the reactor. This is only possible when the reactor is big enough.

 

[tmz]

Carbon dosing is a fine idea,IME. There are many ways to run a reef tank. I personally prefer it to running a denitrator long term.




Denitrators can work well with much less sulfur than some suggest.btw. Read the early sections of the thread for broader viewpoints and application advice and experiences. .

 

[Ben34105]

My tank is almost down to 0 nitrates. I had an issue with mine after a few days so I jumpstarted it with a vial of BioDigest. I poured it in the top and let it sit for a few hours to settle in. I have it running wide open now.

 

[Belgian Anthias]

My tank is almost down to 0 nitrates. I had an issue with mine after a few days so I jumpstarted it with a vial of BioDigest. I poured it in the top and let it sit for a few hours to settle in. I have it running wide open now.

BioDigest is a mix of numerous different strains of heterotrophic bacteria . De-nitration by elemental sulfur is done by autotrophic bacteria. Heterotrophic bacteria need a carbon source. Why adding BioDigest to a sulphur denitrator?
What was the issue you had after a few days?

 

[Belgian Anthias]

Big enough

Big enough

I know a lot of people who had problems with sulphur denitrators but in 99% of the cases these problems occurred because the reactor was not big enough for the system and was mismanaged because of the fact the user did not know it was to small. A sulfur reactor must not be managed the same way a carbon reactor is managed. Most people will start to use a Sdenitrator as a problem solver to reduce high levels. This can not be done when managed the same way a Creactor is managed following the guidelines of some manufacturers of reactors. When used as a problem solver and the parameters of the system are not known a 1% reactor will do the job without being encountered by the limits of the reactor avoiding possible mismanagement. When level decreases, increase the flow true the reactor to be able to remove more than the daily production. When the level of nitrate in the water descends more water has to pass the reactor to make it possible to remove the same quantity of nitrate. Enough space must be available for removing the increased supply of oxygen. That is why it must be big enough!
Sulfhur quantity depends of the daily to remove quantity of nitrate and the desired nitrate level in the system at what level the reactor has to operate.

 

[Ben34105]

Mine was working great then I tested the output preparing to increase flow and it was reading as high as the tank. For some reason it must have crashed.

 

[Belgian Anthias]

crash

crash

Mine was working great then I tested the output preparing to increase flow and it was reading as high as the tank. For some reason it must have crashed.

Did adding Biodigest solved the problem?
Just start it up again. At low nitrate level in the system and high daily nitrate production the start up may be done the opposit way. Instead starting up at very low flow the reactor starts with high flow wich is reduced gradualy until effluent has 0 nitrate and nitrite. As autothropic bacteria start to reduce nitrate at a much higher oxygen level at wich heterothropic bacteria are not able to do the same, autothropic bacteria will have some avantage.

 

[Belgian Anthias]

Carbon dosing is a fine idea,IME. There are many ways to run a reef tank. I personally prefer it to running a denitrator long term.




Denitrators can work well with much less sulfur than some suggest.btw. Read the early sections of the thread for broader viewpoints and application advice and experiences. .

Any amount of sulfur can be used to reduce nitrate as long as the limits of the reactor are respected.
Reducing nitrate is not the same as reducing the nitrate level in the system. To do this, more than the daily nitrate production has to be removed daily. A reactor that is able to do so at a nitrate level of 30ppm may not be able to do the same when a nitrate level of 20 ppm is reached. This reactor will still be able to reduce nitrate but not enough.
To be able to controle the nitrate level in the system the reactor must be big enough to handle the flow needed to remove at least the daily nitrate production daily at any nitrate level.

 

[tmz]

Reducing nitrate reduces the nitrate level in a system by definition unless you add more via foods etc. The amount of sulfur and flow depend on the nitrate level in the system which may vary from time to time in relation to inputs or other events in the system leading to additional fixed nitrogen. Oversizing the amount of suflur and flow results in more aerobic bacterial activity proportionate to anaerobic NO3 reducing activity.

 

[tmz]

As autothropic bacteria start to reduce nitrate at a much higher oxygen level at wich heterothropic bacteria are not able to do the same, autothropic bacteria will have some avantage.

That's not cortrect.

Both autotrophic and heterotrophic bacteria in this case are facultative, thrive in the presence of oxyen or take oxygen from nitrate when ther is no free 02 left in the water.

Chemoautrophic bacteria that use sulfur for energy instead of orgnac carbon used by heterrotrophs don't reduce nitrate(NO3) by taking the O from it ,unless there is no free O available ;they use the free O first. Same for facultative heterotrophic bacteria that use organic carbon for energy. This was all discussed at length earlier in the thread.

 

[Belgian Anthias]

Reducing nitrate reduces the nitrate level in a system by definition unless you add more via foods etc. The amount of sulfur and flow depend on the nitrate level in the system which may vary from time to time in relation to inputs or other events in the system leading to additional fixed nitrogen. Oversizing the amount of suflur and flow results in more aerobic bacterial activity proportionate to anaerobic NO3 reducing activity.

If the amount of sulphur depends on the nitrate level of the system, how much will be used in a system with 40 ppm nitrate? And how much when in the same system the level of 4 ppm is reached? How much may be called "oversized"?

Problems occur mostly when not enough sulphur is used. The amount of sulphur used has effect on NO3 reducing activity only when there is not enough. It is the flow who will influence the BADES (Biological Autotrophe Denitrification with the use of Elemental Sulfur) process.

A Sdenitrator thus not work and is not managed the same way a Cdenitrator is managed. A Cdenitrator must be fed with organic carbonate and the amount of C influences the bacterial activity. Adding or removing sulphur in a Sdenitrator thus not change a thing except when there is not enough!

 

[Belgian Anthias]

As autothropic bacteria start to reduce nitrate at a much higher oxygen level at which heterothropic bacteria are not able to do the same, autothropic bacteria will have some avantage.

That's not cortrect.

Using BADES has the advantage that the flow can be managed in a way that the nitrate level in the system can be stabilized at the desired level. Adjusting the flow in a Cdenitrator is a lot more difficult because of the immediate influence on the process when more oxygen is entered. This is because Authotrope bacteria are less sensitive to the oxygen level as are heterotrope bacteria. Autotrope de-nitrification on sulphur starts already at an oxygen level of +- 3ppm. This makes BADES less vulnerable for flow corrections and easy to manage. One of the reasons why we chose for a Sdenitrator.

 

[Belgian Anthias]

Because I can not edit my reply any more I have to make corrections this way. I changed carbonate in carbon

If the amount of sulphur depends on the nitrate level of the system, how much will be used in a system with 40 ppm nitrate? And how much when in the same system the level of 4 ppm is reached? How much may be called "oversized"?

Problems occur mostly when not enough sulphur is used. The amount of sulphur used has effect on NO3 reducing activity only when there is not enough. It is the flow who will influence the BADES (Biological Autotrophe Denitrification with the use of Elemental Sulfur) process.

A Sdenitrator thus not work and is not managed the same way a Cdenitrator is managed. A Cdenitrator must be fed with organic carbon and the amount of C influences the bacterial activity. Adding or removing sulphur in a Sdenitrator thus not change a thing except when there is not enough!

 

[tmz]

I think you are confusing the issue.

Both facultative heterotrophic and autotrophic bacteria use free oxygen before taking O from nitrate ,thus reducing it to N and N2 gas which leaves the tank.

Heterotrophic bacteria use organic carbon for energy(acetate from ethanol and acetic acid for example),while the facultative thio baccilus use sulfur for enegy and have no need for orgnanic carbon.Both can create localized oxygen free areas in moderate to low flow and niether has an edge in this regard.

In brief ,as discussed at length earlier in this thread, in a sufur dentrator the bacteria will: use the sulfur, reduce the alkalinity and up the sulfate without much if any nitrate reduction in high flow with free oxygen.

I have no idea why you wish to keep comparing hetertrophic nitrate reduction based on acetate( etrhanol, acetic acid) and autrophic reductions based on sulfur, pushing the later as superior. No one asked about it and it seems beyond the scope of this thread.

If you wish to continue doing that there are a number of studies on it you may wish to read to improve your understanding.

This one is on point:

http://www.ncbi.nlm.nih.gov/pubmed/22497708

This is from it:

"...Based on these and our earlier findings the highest nitrate and nitrite removal rates are achieved under heterotrophic conditions with acetate, followed by autotrophic rates with sulfide, and then elemental sulfur...."

 

[Belgian Anthias]

"...Based on these and our earlier findings the highest nitrate and nitrite removal rates are achieved under heterotrophic conditions with acetate, followed by autotrophic rates with sulfide, and then elemental sulfur...."

This is true. We use sulphur because the reactor is easily manageable, the system is reliable and thus not need daily attention. . 1liter of sulphur can remove 0,8kg nitrate/1000l/day at 100%. This may go up till 4.5kg/1000l/day at 30%. This is more than enough.

And I keep on comparing Sdenitrators with Cdenitrators because when a Sdenitrator is managed the same way a Cdenitrator is managed, as a lot of users do, it can only reduce nitrate and it makes the reactor vulnerable for mismanagement and failures.
A BADES System can do a lot more than just reducing nitrate. Managed the right way it gives full control over the nitrate level in the system. but only when enough sulphur is used. No other nitrate reducing method can do that.

 

[Belgian Anthias]

daily nitrate removal

daily nitrate removal

1liter of sulphur can remove 0,8kg nitrate/1000l/day at 100%. This may go up till 4.5kg/1000l/day at 30%. This is more than enough.

I looked it up in my notes and I did not translated and explained this correctly.. I try again:
It is the daily charge of nitrate which will make it possible to modify and determine the quantity of sulphur substrate and the flow. The maximum quantity of nitrate 1 liter sulphur can remove daily is about 3 grams. The max charge for 100% removal is approximately 0.8 kg nitrate/day/m3 S . From that point the efficiency will go down to reach +- 30% at a daily charge of 4.5kg/m3S = +- 1.5g nitrate removal daily for 1l S.

C'est la charge volumique (Cv) exprimée en kilo de N03- par m3 de soufre et par jour qui permet de modéliser les quantitésde substrat et les débits. En cas d'utilisation de billes de soufre de l'ordre de 1.4 mm de diamètre, la quantité maximale de nitrates éliminée semble être d'environ 3 kg de NO3-/m3 S/j. La charge maximale pour obtenir un rendement de 100% sesitue aux alentours de 0,8 kg. Au delà de cette charge, le rendement baisse, il est encore de 30% pour Cv = 4,5 kg NO3/m3
S/j.Michel HIGNETTE,* Benoit LAMORT,* Marc LANGOUET,** Sébastien LEROY* et Guy MARTIN ( 1979 - 1996) Adey ( 1983), Jaubert ( 1988)