Can a sulfur denitrator leak sulfur?

[Reefvision]

Im at the same like 2-3ppm via salifert. Brought from 150ppm to 2.5ppm no3. I actually have to read it from the side which is pink. From the top it looks clearish.

Hi @corey ; so I am monitoring and keeping flow through vertex media reactors regulated so Aston not bottom out no3. Seems to be getting lower now after not much change for couple months. I have increased flow a bit since last week when no3 was down to 5 ppm . Now it’s a bit lower(2 per Red Sea kit — light pink on test vial) I am adjusting thruput to try to prevent bottom out scenario. Po3 tested today (Hanna) .03) so hope to keep these parameters for now if I can . I have a fuge section in sump that has mostly hairy green type algea also so that may be a factor in my numbers. I also have been utilizing purple non sulpher bacteria recently to try to get more “ good” bacteria into play. I am sorry for the run on but I hope to get more solid info to forward soon. Thanks Jim

 

[Belgian Anthias]

I'm not sure I understand the terms you are using, but if you mean:

"If H2S is smelled this means the water is saturated with H2S"

then that is not true. No volatile compound in seawater needs to be saturated (that is, at its solubility limit) to enter the air and be detected by smell.

As far as I know, HS is the liquid form and H2 S is the volatile or gaseous form. The ratio is pH related. Except in pressure systems where mainly the liquid form occurs ( reactors with effluent restriction) up to pH4 only the gaseous form is present, at pH 7 (neutral) the ratio is approximately 50%, at pH8 hydrogen sulfide will be 90% in liquid form, at pH 8.2 this is about 95%. From pH 9, sulfur will be formed and from pH 10 the sulfur amount will increase and the liquid form, which is - 98%, will decrease.

I was wrong to call it saturation!! Saturation is not correct!!. The volatile part may be released and smelled, most of it will be present in liquid form. Water may contain a certain amount of gasses and may get saturated or oversaturated with gasses. If I smell H2S this means it is released into the air. Must I conclude seawater has a certain saturation capacity for gasses but not for H2S? If there is some HS overproduction only +- 5% will be gas at pH 8.2 How much H2S seawater may contain before the gas is released into the air? That is what I meant by saturation. If H2S is not stored in the water to a certain amount before being released we may smell it immediately when HS is produced, otherwise, H2S may build-up to a certain amount ( saturation?) before it may be detected.

 

[Belgian Anthias]

In seawater filter systems, most HS is produced due to anaerobic remineralization using sulfate, and produced HS will be oxidized using nitrate, producing sulfate or and sulfur. The sulfur then may be used for BADES by the same bacteria. HS leftover ( nitrate is used up) will be oxidized aerobically back to sulfate.

If reactors are used, the treated water is aerated before entering the system. This is a standard procedure to stabilize pH.

I do not see how HS may become problematic in a marine aquarium, exempt when a high concentration is released in a short period of time. As BADES systems are not kept in an anoxic state this is not possible using BADES.

 

[Randy Holmes-Farley]

If zero no3 does that mean the sulfur bacteria are increasing sulfate in my water?

If there is O2 around, yes. If there is no O2 and no nitrate, the process will be very slow. It will need some other oxidizer, such as ferric iron.

 

[Randy Holmes-Farley]

As far as I know, HS is the liquid form and H2 S is the volatile or gaseous form. The ratio is pH related. Except in pressure systems where mainly the liquid form occurs ( reactors with effluent restriction) up to pH4 only the gaseous form is present, at pH 7 (neutral) the ratio is approximately 50%, at pH8 hydrogen sulfide will be 90% in liquid form, at pH 8.2 this is about 95%. From pH 9, sulfur will be formed and from pH 10 the sulfur amount will increase and the liquid form, which is - 98%, will decrease.

I was wrong to call it saturation!! Saturation is not correct!!. The volatile part may be released and smelled, most of it will be present in liquid form. Water may contain a certain amount of gasses and may get saturated or oversaturated with gasses. If I smell H2S this means it is released into the air. Must I conclude seawater has a certain saturation capacity for gasses but not for H2S? If there is some HS overproduction only +- 5% will be gas at pH 8.2 How much H2S seawater may contain before the gas is released into the air? That is what I meant by saturation. If H2S is not stored in the water to a certain amount before being released we may smell it immediately when HS is produced, otherwise, H2S may build-up to a certain amount ( saturation?) before it may be detected.

In seawater, hydrogen sulfide takes the forms S--, HS-, and H2S. All co-exist with the ratio depending on pH.

H2S will volatilize, so if there is any amount of S-- and HS-, there will be some H2S and some of that will escape to the air.

 

[Belgian Anthias]

If zero no3 does that mean the sulfur bacteria are increasing sulfate in my water?

No, not at all. Not when using BADES-columns. Or BADES biofilters.

Sulfur bacteria using nitrate as T.denitrificans are not able to oxidize elemental sulfur using oxygen, they are able to use other sulfur compounds using their aerobic pathway, they can only use elemental sulfur using their anaerobic pathway, needing nitrate. ref MB CMF De Haes 2016

The sulfur bacteria will NOT produce sulfate when no nitrate is available.

Zero nitrate means one has no idea of how much nitrate may be available. But it does not mean no nitrate is produced and removed.

Using BADES-rolls nitrogen availability in the water column may become limited, that is why I prefer to maintain a measurable nitrate reserve. In relation to the phosphate reserve, max X9 in weight.

Using denitrators in an anoxic state, maintaining zero nitrates in the water column may become very problematic.

One must make a difference between availability in the water column and availability there where the action is.

Normally nitrifying sulfur bacteria use sulfur compounds as HS, produced due to sulfate reduction by anaerobic remineralization in anoxic zones. Sulfate reduction is done by heterotrophs needing organic carbon, anaerobic remineralization.
In a normal aerobic remineralizing biofilm also anaerobic remineralization takes place. if no nitrate is available sulfate is used as an oxygen source instead of nitrate. In a remineralizing biofilm always nitrate is produced. After complete remineralization of organic matter (OM), only a part of the organic carbon is used for heterotrophic growth as most are needed to provide the energy needed to break down OM and to grow and is released as CO2. This means a lot of basic building materials are leftover. Only +- 1/3 of the nitrogen is used for heterotrophic growth, the rest becomes available as ammonium, together with all other building materials not used for heterotrophic growth, phosphorous, trace elements, etc. In the biofilm most ammonia is transformed to nitrate, nitrate is the end product of aerobic remineralization, together with CO2 and phosphate. It is the intention that the safely stored nitrogen and everything else leftover is used to close the carbon cycle, make reuse of CO2 for to import organic carbon and produce oxygen, restoring the balance between producers and reducers.
Due to the high BOD in the outer layers of the biofilm, not enough oxygen can be transported to the inner layers, promoting autotrophic anaerobic activities, including BADES. Anoxic zones may be created where anaerobic remineralization may take place. If in those anoxic zones not enough nitrate becomes available and remineralization takes place also sulfate reduction takes place, producing HS, normally used by sulfur bacteria for denitrification where nitrate becomes available. Elemental sulfur is added to increase the autotrophic denitrification capacity which means lees nitrate becomes available for anaerobic remineralization, more sulfate is reduced, producing more HS, oxidized back to sulfate.
If remineralization filters are used always enough nitrate will be available there where the action is!!!! That is how BADES based biofilters work.

Theoretically, zero nitrates in the water column is not a problem using BADES as long enough remineralization can take place. (Skimmer?)

This is not the case using reactors kept in an anoxic state as only anaerobic remineralization will take place but no nitrification.

 

[Belgian Anthias]

In seawater, hydrogen sulfide takes the forms S--, HS-, and H2S. All co-exist with the ratio depending on pH.

H2S will volatilize, so if there is any amount of S-- and HS-, there will be some H2S and some of that will escape to the air.

Thanks.
This means if it is produced it can be smelled!

 

[Belgian Anthias]

Aerobic oxidation of elemental sulfur in a marine aquarium, in marine aquaculture systems? It is as far as I know never reported ? At pH below 4? in hot springs?

In the absence of nitrate more sulfur compounds become available in the watercolumn for aerobic oxidation but as in a marine aquarium sulfate is abonded it is most likely about closing the cycle from sulfate back to sulfate.
Nitrate reducing sulfur bacteria are able to oxidize most sulfur compounds aerobically and anaerobically but can oxidize elemental sulfur only following their anaerobic pathway needing nitrate.

In a denitrator kept in an anoxic state nitrate may be limited available by wich produced HS
may be oxidized partially and elemental sulfur is produced. This way a lot of sulfur may be added to the system, wich is not the same as leaking it . This has nothing to do with the elemental sulfur being present in the reactor but with sulfate reduction taking place.

If sulfur is added depends of the nitrate to HS ratio.
Between 2: 5 to 7: 5 the oxidation of HS is partial and from 8: 5 complete. ref:MB Matricaria 2007

My opinion it is possible elemental sulfur is added using a denitrator, not nessecarily a sulfur denitrator.
But as HS is produced using sulfate the total amount of sulfur would be about the same.

 

[Cory]

It will need some other oxidizer, such as ferrous iron.

Ive been dosing ferrous citrate. Is that bad?

 

[Randy Holmes-Farley]

Ive been dosing ferrous citrate. Is that bad?

No, there's not enough iron to cause oxidation and reduction issues in a denitrator. I should have written ferric anyway, and corrected the earlier post of mine.

 

[Cory]

Okay, the sulphur smell came back... the beckett skimmer isnt keeping up lol.

What should i do? Leave it? Take it out? Put it in felt filter bags (BADES ROLLS) or?

It really helped with the no3 150ppm down to 2.5ppm. Id hate to not have one.

 

[Belgian Anthias]

My understanding of this process which I am not sure is correct at all is that the sulpher needs to be in fed oxygen rich flow and "regulated" to keep sulpher bacteria from consuming itself without food(no3) . I am using something similar to what @Belgian Anthias describes to slow feed/ faster feed water flow to keep No3 at ok level ( I am @ 2ppm today) after starting approx 2 months ago . Taking baby steps lol.started above 30 ppm .

BADES columns are remineralization filters. They have a high BOD ( biological oxygen demand) depending on the DOC production and TOC supply. Such a filter breaks down organic matter and removes DOC, it keeps DOC low which is a lot more important than the presence of a nitrate reserve. Nitrate is produced. Due to the BOD demand on and in the outer layers of the biofilm or BADES rolls oxygen minimum zones are created on the inside and some anoxic zones on the surface, on the substrate. Produced nitrate can be removed by denitrification, autotrophic and heterotrophic.

The sulfur bacteria can not consume themselves without food, they are autotrophs. They are able to use up their stored nutrient reserves to survive a prolonged period of time, without growing. They do not form cysts. Dead bacteria will be "consumed", remineralized, by heterotrophs, producing HS if done by anaerobic remineralization. ( no nitrate is produced in anoxic zones but ammonia, sulfate is used as an oxygen source) In a normal biofilm produced HS will be oxidized, if not anaerobically reducing nitrate, it will be done aerobically and it can be done by the same sulfur bacteria. Both processes produce sulfate. From sulfate back to sulfate.


BADES columns do not depend on nitrate present in the water column but it is advised to keep on a minimal detectable nitrate reserve. This makes it possible to follow up the nitrogen availability and prevents too much nitrogen may be exported.

One must keep in mind only nitrogen is removed, all the rest is left behind and may not be reusable due to nitrogen limitation. Removing safely stored nitrogen does not solve a thing as nothing is done to correct the source of the nitrogen reserve. Why a usable nitrogen reserve can build up in a well-lit aquarium?

It is not the sulfur needing good flow, it is the remineralization capacity of the filter. Remineralization removes organic waste and removes produced ammonia by transforming the ammonia to nitrate, used by the sulfur bacteria.

By managing the flow one is able to manage the oxygen supply. Using a refuge one is able to manage the nitrate level as desired by the user.

BADES Columns should be placed hanging free in the water, water may not be forced true the filter.



There are a lot of different sulfur bacteria but there are only a few who are specialized in using nitrate to oxidize sulfur. In BADES filters mainly T. denitrificans are responsible for oxidizing sulfur using nitrate. They do not depend on the presence of organic waste or food to prosper. They have the ability to use both pathways to retrieve oxygen and are able to function aerobically and anaerobically. They can switch over from oxygen to nitrate. They do NOT need NITRATE to survive as long there is a sulfur source they can use. Their food is sulfur, not nitrate!! They are very active in oxygen transition zones, they do not need an anoxic environment, the moment not enough oxygen can be supplied to fulfill the demand they switch over to nitrate. Only when using nitrate they are able to oxidize elemental sulfur. In an environment where growth is exponential, the biological oxygen demand ( BOD) can double at any moment.
T. denitrificans will NOT die off if no nitrate is available but growth will be limited. T.denitrificans will try to be as close as possible to the source of sulfur production. In an aerobic remineralization filter, this will be mainly close to the substrate where anoxic zones are created, making anaerobic remineralization possible and Sulfur compounds as HS are produced.

What we do is adding elemental sulfur to a remineralization filter to ensure sulfur is not the growth limiting factor for denitrification and limit the need for HS production, anaerobic remineralization, and anoxic zones. We do NOT try to prevent sulfate reduction as it is a normal and essential process in a nitrifying biofilm. The denitrification capacity of a normal remineralization filter can this way be increased to the level of nitrate production.

In a denitrator kept in an anoxic state, a lot more HS is produced as nitrate is not produced in the filter. Present and produced TOC and DOC is remineralized anaerobically., a lot of HS may end up in the water. Only nitrate present in the water column will prevent sulfate reduction, targeting 0 nitrates in the effluent is not a good idea.
In a sulfur denitrator kept in an anoxic state, the same may happen, but as the sulfur bacteria are not able to switch over to oxygen they will die off when nitrate is used up. HS will not be removed.

A BADES system is NOT kept in an anoxic state,!

BADES columns or rolls are very effective for exporting nitrogen, too much nitrogen may be exported. Nitrogen is part of the building materials left over after the complete remineralization of organic matter. If too much nitrogen is removed the balance between nitrogen availability and the presence of all other essential building materials may be lost. For example, the phosphate reserve may increase because there is not enough nitrogen to make good use of it.

 

[Belgian Anthias]

No, there's not enough iron to cause oxidation and reduction issues in a denitrator. I should have written ferric anyway, and corrected the earlier post of mine.

It is NOT a denitrator, it is a remineralization filter! Everything is supplied!!!

 

[Belgian Anthias]

Okay, the sulphur smell came back... the beckett skimmer isnt keeping up lol.

What should i do? Leave it? Take it out? Put it in felt filter bags (BADES ROLLS) or?

It really helped with the no3 150ppm down to 2.5ppm. Id hate to not have one.

it is obvious you have to determine the source. You do mean the smell of rotten eggs? Then you have to look for places where anoxic conditions may occur, starting with removing the filter. It may partially be clogged preventing sufficiënt water exchange. If water is forced to flow true the media, tunneling may occur.

Pure dry Elemental sulfur has a typical odor, but it does not smell like rotten eggs, the odor is not degusting or penetrative.

As I do not know how the filter is made and managed I can not help you, so it is best to remove it and look at what happens.

As nitrates are at an expectable level maybe you can make use of an AAF, activated algae filter, which is a much better solution to manage the nutrient content, all nutrients.

The presence of nitrate is never an emergency, most methods used to remove safely stored nitrogen may create conditions a lot worse than the presence of nitrate. Sulfur denitrators, denitrators, organic carbon-based products, carbohydrates, etc As long not the source is corrected nothing is solved.
The same for the production of H2S. Trying to remove it without correcting the source does not solve a thing.

If the principles of a BADES system are followed HS is removed when produced. Anyway, if it is H2S, it is not produced because of the presence of elemental sulfur.

Places with deep sand? Clogged live rock? Porous stones, media? A dead animal in the sandbed
Use of organic carbon, adding products to battle algae, cyano?
Use of GAC?
Places where sulfur compounds can be produced and promoted.

New grazers removing old cushions, releasing in deep pores stored HS.

S produced due to partial HS oxidation using nitrate? Normally it is used where it is produced but it may leak into the water. The production is very limited. I know it has a different composition but I do not know if it may give a special smell to the water. Very unlikely, but I try to find a reason for the water smelling like sulfur.

 

[Reefvision]

BADES columns are remineralization filters. They have a high BOD ( biological oxygen demand) depending on the DOC production and TOC supply. Such a filter breaks down organic matter and removes DOC, it keeps DOC low which is a lot more important than the presence of a nitrate reserve. Nitrate is produced. Due to the BOD demand on and in the outer layers of the biofilm or BADES rolls oxygen minimum zones are created on the inside and some anoxic zones on the surface, on the substrate. Produced nitrate can be removed by denitrification, autotrophic and heterotrophic.

The sulfur bacteria can not consume themselves without food, they are autotrophs. They are able to use up their stored nutrient reserves to survive a prolonged period of time, without growing. They do not form cysts. Dead bacteria will be "consumed", remineralized, by heterotrophs, producing HS if done by anaerobic remineralization. ( no nitrate is produced in anoxic zones but ammonia, sulfate is used as an oxygen source) In a normal biofilm produced HS will be oxidized, if not anaerobically reducing nitrate, it will be done aerobically and it can be done by the same sulfur bacteria. Both processes produce sulfate. From sulfate back to sulfate.


BADES columns do not depend on nitrate present in the water column but it is advised to keep on a minimal detectable nitrate reserve. This makes it possible to follow up the nitrogen availability and prevents too much nitrogen may be exported.

One must keep in mind only nitrogen is removed, all the rest is left behind and may not be reusable due to nitrogen limitation. Removing safely stored nitrogen does not solve a thing as nothing is done to correct the source of the nitrogen reserve. Why a usable nitrogen reserve can build up in a well-lit aquarium?

It is not the sulfur needing good flow, it is the remineralization capacity of the filter. Remineralization removes organic waste and removes produced ammonia by transforming the ammonia to nitrate, used by the sulfur bacteria.

By managing the flow one is able to manage the oxygen supply. Using a refuge one is able to manage the nitrate level as desired by the user.

BADES Columns should be placed hanging free in the water, water may not be forced true the filter.



There are a lot of different sulfur bacteria but there are only a few who are specialized in using nitrate to oxidize sulfur. In BADES filters mainly T. denitrificans are responsible for oxidizing sulfur using nitrate. They do not depend on the presence of organic waste or food to prosper. They have the ability to use both pathways to retrieve oxygen and are able to function aerobically and anaerobically. They can switch over from oxygen to nitrate. They do NOT need NITRATE to survive as long there is a sulfur source they can use. Their food is sulfur, not nitrate!! They are very active in oxygen transition zones, they do not need an anoxic environment, the moment not enough oxygen can be supplied to fulfill the demand they switch over to nitrate. Only when using nitrate they are able to oxidize elemental sulfur. In an environment where growth is exponential, the biological oxygen demand ( BOD) can double at any moment.
T. denitrificans will NOT die off if no nitrate is available but growth will be limited. T.denitrificans will try to be as close as possible to the source of sulfur production. In an aerobic remineralization filter, this will be mainly close to the substrate where anoxic zones are created, making anaerobic remineralization possible and Sulfur compounds as HS are produced.

What we do is adding elemental sulfur to a remineralization filter to ensure sulfur is not the growth limiting factor for denitrification and limit the need for HS production, anaerobic remineralization, and anoxic zones. We do NOT try to prevent sulfate reduction as it is a normal and essential process in a nitrifying biofilm. The denitrification capacity of a normal remineralization filter can this way be increased to the level of nitrate production.

In a denitrator kept in an anoxic state, a lot more HS is produced as nitrate is not produced in the filter. Present and produced TOC and DOC is remineralized anaerobically., a lot of HS may end up in the water. Only nitrate present in the water column will prevent sulfate reduction, targeting 0 nitrates in the effluent is not a good idea.
In a sulfur denitrator kept in an anoxic state, the same may happen, but as the sulfur bacteria are not able to switch over to oxygen they will die off when nitrate is used up. HS will not be removed.

A BADES system is NOT kept in an anoxic state,!

BADES columns or rolls are very effective for exporting nitrogen, too much nitrogen may be exported. Nitrogen is part of the building materials left over after the complete remineralization of organic matter. If too much nitrogen is removed the balance between nitrogen availability and the presence of all other essential building materials may be lost. For example, the phosphate reserve may increase because there is not enough nitrogen to make good use of it.

Thanks for the detail ed info

 

[Cory]

Pure dry Elemental sulfur has a typical odor, but it does not smell like rotten eggs, the odor is not degusting or penetrative.

Yes the water had the smell of pure dry elemental sulfur. Not like rotten eggs. Strange.

If the principles of a BADES system are followed HS is removed when produced. Anyway, if it is H2S, it is not produced because of the presence of elemental sulfur.

Im going to make bades rolls soon when i have time with felt mesh.

 

[Cory]

Oh also an update, i added 3 cups of tank water inside the denitrator to hopefully add something to stop h2s.

I also.l added some gfo to remove h2s. Seems to have worked a day later. No smell!

 

[Reefvision]

I am by not any means a expert at any of the chemical processes going on exactly but what I do is similar to you Cory except that I regulate water flow through the "tube" ( in my case two media reactors ) to Prevent anoxic condition and the sulpher is doing its job and nitrate has been under control now after starting to go higher than I feel was safe. Getting oxygenated water flow( not drips) . Steady stream though. Been trying to use this BADES type of system few months now and so far no ill effect noted. I think if you get some water flow thru your tube your smell issue could go bye-bye. Good luck. Best regards, Jim.

 

[Cory]

I am by not any means a expert at any of the chemical processes going on exactly but what I do is similar to you Cory except that I regulate water flow through the "tube" ( in my case two media reactors ) to Prevent anoxic condition and the sulpher is doing its job and nitrate has been under control now after starting to go higher than I feel was safe. Getting oxygenated water flow( not drips) . Steady stream though. Been trying to use this BADES type of system few months now and so far no ill effect noted. I think if you get some water flow thru your tube your smell issue could go bye-bye. Good luck. Best regards, Jim.

Got a pic of your sulfur denitrator setup? Mine doesn't use a pump just natural flow through it. Alkalinity hasn't been noticeably impacted until i started smelling this h2s smell.

 

[Cory]

Update:
unfortunately i had to take the unit out, not because there was a smell, there wasn't, but because my panther grouper stopped eating. I checked alkalinity and it dropped to 6.4dkh! Never been so low. Usually its 7.8dkh via limewater for months. Adjusted immediately with baking soda to 7.7dkh.

Upon taking the unit out the outflowing water reeked of rotten eggs. wont be ysing the tube design as pasive denitrator again. Lesson learned.

Whats interesting is before all this h2s smell, the tanks alkalinity didn't have any effect (didn't lower) that i could detect, but no3 dropped to 2.5ppm from 150ppm. But when i detected the h2s smell, alkalinity was dropping daily. Yesterday's alk was 7.0. I upped the limewater dose. Todays was 6.4dkh!

I also added a fresh cup of gfo so maybe the alk dropped for that too?