DIY Sulfur Denitrator

[tmz]

Your English is excellent. I appreciate the effort and the links you shared.

I understand your point of view but disagree with it.

The amount of nitrate when one starts a denitrifier is usually high. The amount of sulfur used may be higher than one needs, once an initial reduction is accomplished and /or some off the causes for higher nitrate are addressed.
Once high nitrate is reduced by a sulfur denitrifier, day to day nitrate levels may be lower requiring less bacterial activity to reduce them and less sulfur to feed them.

Many times nitrate levels may stay low enough after an initial redcution to lessen the need for a denitrator which can be made smaller by reducing the amount of sulfur or can be taken off line completely rather than running it with the same amount of sulfur in high flow /high oxygen mode where very little to no nitrate redcution occurs but sufate and organics continue to be produced as the bacteria operate in aerobic mode.
Adjusting the amount of sulfur manages the food supply to the bacteria. Manipulating the flow regulates the supply of nitrate( variable based on amounts in the aquarium water) and oxygen .
Getting nitrate reduction without anoxia and without excessive aerobic activity while maximizing anaerobic nitrate reduction is a better balance in my opinion.

 

[tmz]

And all methods for removing nitrates have their cons and for but the main question we must ask is: why do we need one?

They have different benefits too as well as the potentenial negatives.

Some examples of benefits setting aside the nitrate reduction :

Macro alge refugia provide: habitat for microfuana,extra oxygen from photosynthesis, reduce CO2 which translates to higher pH.

Running granulated activated carbon reduces organic compounds in the water:some of which may be alellopathic ;some that discolor the water and helps keep the total oragnic carbon in the aquarium down.

Skimming provides aeration in addition to removing organic materials.

Organic carbon dosing cultures bacteria that consume inorganic phosphate and nitrogen and provide bacteria likely useful for food by the food web in general . I've been using vodka and vinegar for 5.5 years with no negative consequences, FWIW.

Extra surface area for bacteria to colonize via extra sand bed areas or live rock areas can alsobe useful.

Cryptic refugia can support filter feeders including sponges which convert inorganic nutrients to useful and more exportable forms.

 

[Belgian Anthias]

IMO, one of the significant drawbacks of sulfur denitrator is the depletion of alkalinity. Yes, one can compensate for that by adding extra aklalinity, but for those of us trying to use balanced calcium and alkalinity additive systems, such a depletion messes up that balance and requires more monitoring of calcium and alkalinity than might otherwise be needed.

Passing the water over aragonite may help boost the alkalinity, but it also boosts calcium, so at best, it just swaps a depletion of alkalinity for a steady boosting of calcium.

Of coarse you make it as small as you want! But it will not be able to remove the nitrate when nitrate is building up.

That obviously depends on the rate of feeding, and what other nitrate reduction methods are in place. I prefer to use many nutrient export method at the same time, rather than have to rely on one to carry the full load. That is especially important as almost all of these methods export some N and P, but not likely the exact ratio present in the tank. So having multiple methods allows one to pick up the slack of the others.

Shore, Why use a de-nitrator when the system is well managed and in balance?
This topic is about Sulfhur de-nitration and even not at its place here because it is about a DY project. People who want to build a sulphur de-nitrator should also have notice of how to manage it. That is what I try to do and explain. It is not my goal to propagate sulfhur de-nitration in favor of other methodes. When asked I give my opinion.
And I say again. No, the reactor must not be based on the other methods used and the nitrate available, it must be based on the systems volume for easy management. This way you do not have to switch methods, you can use them together as long as you don't go to fill it with VODKA. You can leave it in the system when nitrate is not measurable. That is one of the reasons it must be big enough so that high flow till 10% can be managed.
Once nitrate is low PH will will drop by the activity of aerobic bacteria more than by anaerobic activity and good aeration of the effluent will help to stabilize.

 

[CHSUB]

nice to see this thread with some life...ime, most of the sulfur denitrators here are undersize and not properly set-up, making them hard to control. i'm using 2 gallons of sulfur on a 350 TV dt heavily stocked and it's not processing enough water. i'm waiting on a larger reactor so i can go to 4 gallons of sulfur. imo, the 1% rule seems valid.

 

[Belgian Anthias]

Your English is excellent. I appreciate the effort and the links you shared.

I understand your point of view but disagree with it.

The amount of nitrate when one starts a denitrifier is usually high. The amount of sulfur used may be higher than one needs, once an initial reduction is accomplished and /or some off the causes for higher nitrate are addressed.
Once high nitrate is reduced by a sulfur denitrifier, day to day nitrate levels may be lower requiring less bacterial activity to reduce them and less sulfur to feed them.

Many times nitrate levels may stay low enough after an initial redcution to lessen the need for a denitrator which can be made smaller by reducing the amount of sulfur or can be taken off line completely rather than running it with the same amount of sulfur in high flow /high oxygen mode where very little to no nitrate redcution occurs but sufate and organics continue to be produced as the bacteria operate in aerobic mode.
Adjusting the amount of sulfur manages the food supply to the bacteria. Manipulating the flow regulates the supply of nitrate( variable based on amounts in the aquarium water) and oxygen .
Getting nitrate reduction without anoxia and without excessive aerobic activity while maximizing anaerobic nitrate reduction is a better balance in my opinion.

Ok, How thus your reactor work? Are you satisfied with it? Why do you worry about sylfide production and anoxia? Thus the nitrate in your aquarium drops when you increase the flow? Or when you decreases the flow.
Test it!
You do NOT have to manage the food supply of the bacteria by the amount of sulphur, there is enough for years to go! The sulphur is mainly used as substrate for the bacteria to grow and only a small part is consumed. There are all all kinds of bacteria that can and will grow on the sulphur but not all van use it. Only those autotropic bacteria, which name I only know by publications of others, will be able to feed and survive on the sulphur.
You want to know exactly what happens and which bacteria are responsible exactly?
I do not know but I can tell you that reactors I used worked for more than 10 years the way I explained without any main problems. We changed 1/4 of the sulphur every year and changed a failed pump. We change 1/4 of the water every three months and hold the nitrate between 1 and 2ppm. We used the reactors at start up and nitrate has never been above 5ppm>.

 

[Belgian Anthias]

Sulpur-denitrators where lab tested and used in public aquaria for a long time. Everything about the working is known.

Perhaps I missed it, but I didn't see a single thing that you linked to or posted that showed any evidence that Thiobacilllus denitrificans is the bacteria that grows in reef tank sulfur denitrators. Did I miss it, or are you just assuming that because it is known in environments like soil that it must be the species growing in denitrators?

You mist this:They are probably not always the primary species in the reactor, but at my knowledge they are the only common autotropic NO3 to N reducing bacteria with an optimum working temp between 25°C and 30°C and PH range between 6 and 8. All others need optimum temps above 30°C, a narrow PH range of 7 or work only in very acidic conditions. It is evident that when nitrate has to be reduced in an aquarium of 27°C they have the best cards to play.
You are the specialist, not me. What do you think?

 

[Belgian Anthias]

Sorry, I missed the last post where you indicated that it might be other species.

One other thing of interest I found there was this comment:

"CHEMISTRY AND THE AQUARIUM by RANDY HOLMES-FARLEY: maybe you find the correct information in some articles of this author because I am not a chemist, only a hobbyist with some interests in how things work."

Thanks for the suggestion. I'm very familiar with my own articles.

I just wanted to show I am aware of your interesting work. You most certainly know what is going on in an aquarium. I just try to explain how a sulphur de-nitrator can easily be managed. What happens at the inside is open for discussions for which other people are better qualified than me.
Following a bit these topic, most of the builds are to small and mismanaged in my point of view. The system I describe does not need knowledge of what happens inside. Used in a normal aquarium the limits can not be reached and it is easy managed. More nitrate to remove, less flow and vis versa, that is all! Find the balance and the work will be finished without the knowledge of a chemists. It can be used by everybody. A to small reactor reaches his limits fast and needs a lot of attention of someone who knows what is going on.

 

[Belgian Anthias]

nice to see this thread with some life...ime, most of the sulfur denitrators here are undersize and not properly set-up, making them hard to control. i'm using 2 gallons of sulfur on a 350 TV dt heavily stocked and it's not processing enough water. i'm waiting on a larger reactor so i can go to 4 gallons of sulfur. imo, the 1% rule seems valid.

The 1% rule is not my invention but established during years of lap tests en The use in public aquaria in the late 80 and the 90 ties. I have experienced that the big advantage in applying this rule is that the reactor by normal use can not reach its limits and stays always easily manageable.

 

[CHSUB]

The 1% rule is not my invention but established during years of lap tests en The use in public aquaria in the late 80 and the 90 ties. I have experienced that the big advantage in applying this rule is that the reactor by normal use can not reach its limits and stays always easily manageable.

yes, i understand it is not your invention. i have only confirmed that, ime, it is true. i also believe that using an ORP controller makes the Sulfur reactor much easier and i would not use one without it.

 

[Belgian Anthias]

nice to see this thread with some life...ime, most of the sulfur denitrators here are undersize and not properly set-up, making them hard to control. i'm using 2 gallons of sulfur on a 350 TV dt heavily stocked and it's not processing enough water. i'm waiting on a larger reactor so i can go to 4 gallons of sulfur. imo, the 1% rule seems valid.

You can make a de-nitrator from any container which can be closed air tight.
Make shore to make it fluidized.

 

[tmz]

Ok, How thus your reactor work? Are you satisfied with it?

Yes I'm satisfied with it .When the nitrate dropped in the system the reactor produced some H2S. I increased the flow and reduced the sulfur and it stopped . It works just fine . Friends have borrowed it and I've helped them use it sucessfully as well. I don't need it anymore for my main system which holds nitrate at 0.2ppm without it despite very heavy feeding and a heavily stocked biolaod. I do use it on some of the other tanks I run from time to time with a proper amount of sulfur to suit each application. Why do you have to run it for years and years in your tank? What's wrong ? Is your tank producing hugh amounts of nitrate contiuously; if so why? or are you just running it in aerobic mode with no real benfit?

 

[tmz]

This topic is about Sulfhur de-nitration and even not at its place here because it is about a DY project.

That's right but you pushed the comparison to other methods citing it as the best safest method which required an inquiry as to why you thought so.No one else intitiated those comparisons",a sulphur de-nitrator is the best and safest system available." from your post #1251 and in an inaccurate extraordinary simplistic assessment criticized other methods as very dangerous and toxic while never mentioning the toxicity of H2S.

 

[tmz]

You do nOT have to manage the food supply of the bacteria by the amount of sulphur, there is enough for years to go! The sulphur is mainly used as substrate for the bacteria to grow and only a small part is consumed

I don't think so. Less access to sulfur equals less bacteria .If they were unlimited by the amount of sufur they're would be enough bacterial mass to exhaust all of the oxygen and nitrate even if flow was high. "The quantity of sulfur to use depends on the initial nitrate level at startup and on the amount of food added"

 

[tmz]

Find the balance and the work will be finished without the knowledge of a chemists.

I'm not a chemist but I can't imagine how anyone would have figured out sulfur bacteria dentirification in a sulfur denitrator without chemisitry in the first place . You may be happy without knowing what is happening in your application; I'm not. "Finding a balance" is very vague without consideration of the reactions actually occurring and the effects on the aquarium.

 

[Belgian Anthias]

You do nOT have to manage the food supply of the bacteria by the amount of sulphur, there is enough for years to go! The sulphur is mainly used as substrate for the bacteria to grow and only a small part is consumed

I don't think so. Less access to sulfur equals less bacteria .If they were unlimited by the amount of sufur they're would be enough bacterial mass to exhaust all of the oxygen and nitrate even if flow was high. "The quantity of sulfur to use depends on the initial nitrate level at startup and on the amount of food added"

If they were unlimited by the amount of sufur they're would be enough bacterial mass to exhaust all of the oxygen and nitrate even if flow was high. : The de-nitrification is limited by the flow, the amount of oxygen and nitrate that can enter the reactor NOT the amount of sulfhur.( Of coarse they will be limited when there is not enough.) There must be enough sulphur to handle any condition. A 1% reactor can handle any situation without calculations have to be made how many nitrate should be removed. The reactor will not reach its limits in a normal aquarium system and will be easily manageable by everybody. A 1% reactor can be installed at start up of the aquarium without knowing how many animals and food will be added. it will work at any condition. If the goal is to install a reactor to remove a high amount of nitrate ( what went wrong?) it can be build based on the amount nitrate to remove because the capacity is based on the high nitrate level. Most of the builds are to small. The question is than: how many sulfur to use? When a 1% reactor is used this question must not be asked and is answered the same time.

The quantity of sulfur to use depends on the initial nitrate level at startup and on the amount of food added: At start up of the reactor nitrate is 20ppm in a 500l aquarium system. How many sulphur would you use? My reactor would contain 5l sulphur. And yours?

 

[Belgian Anthias]

This topic is about Sulfhur de-nitration and even not at its place here because it is about a DY project.

That's right but you pushed the comparison to other methods citing it as the best safest method which required an inquiry as to why you thought so.No one else intitiated those comparisons",a sulphur de-nitrator is the best and safest system available." from your post #1251 and in an inaccurate extraordinary simplistic assessment criticized other methods as very dangerous and toxic while never mentioning the toxicity of H2S.

When the flow is decreased when nitrate builds up for a to small reactor its limits will be reached soon and bacteria will die because the flow will become near 0. To solve the problem a big enough reactor must be used. Again, when H2S is produced the flow is to low, the reactor is clogged or the effluent is tunneling true the media. When using a fluidized bed reactor tunneling and clogging is eliminated leaving not enough flow. Not enough flow means that the reactor is not big enough to remove the nitrate. When the 1% rule is applied this problem is solved and creation of H2S will not be possible except when mismanaged. For example when flow is decreased when nitrate decreases. Flow will become that low anoxic condition will be created. Increasing the flow will solve the problem.

 

[Belgian Anthias]

Ok, How thus your reactor work? Are you satisfied with it?

Yes I'm satisfied with it .When the nitrate dropped in the system the reactor produced some H2S. I increased the flow and reduced the sulfur and it stopped . It works just fine . Friends have borrowed it and I've helped them use it sucessfully as well. I don't need it anymore for my main system which holds nitrate at 0.2ppm without it despite very heavy feeding and a heavily stocked biolaod. I do use it on some of the other tanks I run from time to time with a proper amount of sulfur to suit each application. Why do you have to run it for years and years in your tank? What's wrong ? Is your tank producing hugh amounts of nitrate contiuously; if so why? or are you just running it in aerobic mode with no real benfit?

I use it as part of the system, not as a problem solver, and we try to keep the nitrate level between 1 and 2 ppm.

When the nitrate dropped in the system the reactor produced some H2S: this should not be possible. Did you decrease the flow when nitrate dropped?
I increased the flow and reduced the sulfur and it stopped Why removing sulphur when only increasing the flow should solve the problem?
What will you do when nitrate raises again?

 

[Belgian Anthias]

yes, i understand it is not your invention. i have only confirmed that, ime, it is true. i also believe that using an ORP controller makes the Sulfur reactor much easier and i would not use one without it.

ORP readings can tell you something about what is going on when used on a fluidized reactor. Efforts are made to use ORP and PH to automate the flow. When not fluidized the readings will be misleading when effluent is tunneling true the media. When following the 1% rule ORP readings are not a necessity at all.
If I can make a supplemental investment I would first install PH monitoring.
Why should you never use a sulfur de-nitrator without ORP monitoring?

 

[Belgian Anthias]

Sulpur de-nitrator and managing it.

Sulpur de-nitrator and managing it.

Using a Sulfur de-nitrator should not be difficult.
Based on a 1% reactor ( 1l sulfur for 100l water) You do not have to worry about how many sulfur to use for the amount of nitrate to remove or the production of H2S.( if managed the right way!) Try to keep the flow between 2% and 5% of the aquarium system volume. Even at a flow of 10% a 1% reactor will still be active and ready to do what it is made for.
During incubation small amounts of sulfide or nitrite can be formed but it is harmless because at that moment flow is very low. To exclude all risks the effluent can be wasted. Doing this during a water change wasting water is eliminated.

Once running the nitrate in the effluent should be lower than in the system water now knowing the reactor works. Do not try to remove the nitrate to fast. Its not good to change the reached balance in your aquarium system to fast. Decrease the flow a little bit when you want it to happen faster. Do not try in the beginning to create an effluent with 0 nitrate because when the reactor is to small flow will become that low to reach that point you risk anoxic conditions. Using a 1% reactor will prevent this! The 1% reactor will not reach its maximum capacity to reduce the effluent to 0 nitrate (below 50ppm)
Basic rule: more de-nitration decrease flow, less de-nitration increase flow. This is important!

What happens when doing the opposite?

When the flow is decreased when nitrate lowers you will bring in less oxygen and less nitrate creating more anaerobic conditions for less nitrate. The nitrate will reduce faster and one will think everything works fine and nitrate will become or stay 0 in the effluent. If the effluent is reduced more because the nitrate is almost at the point which is desired a to small reactor can reach already its limits. You will only know it when it is to late. You have made yourself a H2S factory!
Conclusions will be made that a sulpur de-nitrator is dangerous!
This way managed also a 1% reactor will reach its limits!

When the flow is increased when nitrates build up more oxygen and more nitrate enters the reactor but less anaerobic activity will be possible because more free oxygen has to be depleted first. Nitrite will be formed which will be oxidized. You will think the reactor does not work and increase more. At the end a normal BIO has been created and the conclusion will be made a sulphur de-nitrator does not work.
If consideration is made to change the quantity of sulphur to cope with low nitrate levels you must have good reasons because it is should not be necessary.

This is what I wanted to tell, because I think most reactors used are to small and/or managed the wrong way.

I will not go into discussions any more to prove what I wrote above. I am not qualified. If you have doubts, try it.

 

[tmz]

"The quantity of sulfur to use depends on the initial nitrate level at startup and on the amount of food added"



At start up of the reactor nitrate is 20ppm in a 500l aquarium system. How many sulphur would you use? My reactor would contain 5l sulphur. And yours?


That quote clearly indicates a relationship between sulfur amount and nitrate level. It's from the1998 paper you cited earlier; not my invention. Clearly after 16 years the 1% increase the flow method can be refined to avoid ongoing sulfate production and alkalinity consumption by better managing the amount of sulfur in use in conjuction witt manipualting teh flow.

Let's look at a few scenarios:

How much sulfur would you use for 500L with 5pppm NO3?

How much for 500l with 50 ppm NO3.

Let's use 500 liters with 80ppm NO3 to illustrate the point . How much sulfur would you use at start up?