DIY Sulfur Denitrator

[BROTHERSPIZZERIA]

I've had my reactor running for a while now. Started with one gallon of media wasn't enough. Now have 2 gallons of media. Effluent is 0 tank is still 40 plus. I've been increasing the flow about once every few weeks. Is there such a thing as to much flow? I'm at a super fast drip. If I speed up anymore it will almost me a steady stream.

 

[Belgian Anthias]

I've had my reactor running for a while now. Started with one gallon of media wasn't enough. Now have 2 gallons of media. Effluent is 0 tank is still 40 plus. I've been increasing the flow about once every few weeks. Is there such a thing as to much flow? I'm at a super fast drip. If I speed up anymore it will almost me a steady stream.

How much is fast drip? Is de nitrate level in the system water increasing or descending? Do you keep records? If your nitrate level stays level this means you are removing the daily nitrate production. To lower the level the nitrate charge has to increase so flow must increase. To keep on the same nitrate charge you have to increase the flow when the nitrate level decreases. Do this regularly until the desired nitrate level is reached. With 2 gal of media a flow of +-10 gal/h may be normal at low nitrate levels. Flow depends on the daily to remove nitrate production and the nitrate level in the system. Max flow can go up to +- 20 gal/h ( +-10 gal/gal S) For easy management flow should reach at least the total volume of the system daily ( nitrate level in the system < 2 ppm). You have enough S media to accomplish this.

 

[rclendan]

I am experimenting with a 24" DIY recirculating S-Denitrator with a mixed bed consisting of ~1 liter of sulfur prills and ~2 liters of aragonite media. I have a 10 inch cartrige filter holder full of ceramic media plumbed before the unit to add some surface area for aerobic bacteria to consume oxygen and lower the ORP. I have installed some injection ports in the feed line and in the denitrator body so I can feed carbon in the form of sugar solution. I also maintain the unit at 90 degrees F (32 degrees C) for optimal denitrification. when I run the unit without any supplemental carbon, I can only get a relatively small amount of 0 ppm nitrate 1-2 drops per second (< 1 liter per hour) effluent, but when I drip 0.15% sucrose solution at (~15 drops per minute) into the inlet line, I can run the unit at 3-4 liters per hour with 0 ppm effluent. I assume the carbon is either contributing the sulfur denitrating bacteria's biomass, or it is being consumed by aerobic bacteria in the pre-chamber, accelerating the drop in ORP (probably a bit of both), allowing for a higher flow rate. Direct carbon addition also speeds up the cycle (< 1 hour in some cases) when starting, or after opening the unit for cleaning.

The difficulty is in determining the carbon consumption of the unit as not to introduce stray carbon into the aquarium. It is also fiddly to maintain a steady carbon the drip rate. I'd rather dose a small amount of CO2 directly (6-10 bubbles a minute, keeping the pH around 6.8) and get some benefit from the calcium reaction while feeding the carbon fixing bacteria.

Anybody have experience with this? Has anybody tried using CO2 with these units.

 

[Belgian Anthias]

I am experimenting with a 24" DIY recirculating S-Denitrator with a mixed bed consisting of ~1 liter of sulfur prills and ~2 liters of aragonite media. I have a 10 inch cartrige filter holder full of ceramic media plumbed before the unit to add some surface area for aerobic bacteria to consume oxygen and lower the ORP. I have installed some injection ports in the feed line and in the denitrator body so I can feed carbon in the form of sugar solution. I also maintain the unit at 90 degrees F (32 degrees C) for optimal denitrification. when I run the unit without any supplemental carbon, I can only get a relatively small amount of 0 ppm nitrate 1-2 drops per second (< 1 liter per hour) effluent, but when I drip 0.15% sucrose solution at (~15 drops per minute) into the inlet line, I can run the unit at 3-4 liters per hour with 0 ppm effluent. I assume the carbon is either contributing the sulfur denitrating bacteria's biomass, or it is being consumed by aerobic bacteria in the pre-chamber, accelerating the drop in ORP (probably a bit of both), allowing for a higher flow rate. Direct carbon addition also speeds up the cycle (< 1 hour in some cases) when starting, or after opening the unit for cleaning.

The difficulty is in determining the carbon consumption of the unit as not to introduce stray carbon into the aquarium. It is also fiddly to maintain a steady carbon the drip rate. I'd rather dose a small amount of CO2 directly (6-10 bubbles a minute, keeping the pH around 6.8) and get some benefit from the calcium reaction while feeding the carbon fixing bacteria.

Anybody have experience with this? Has anybody tried using CO2 with these units.

This is a very complicated system which in my point of view has nothing to do with a sulfur-denitrator or BADESS ( Biological Autotrophe Denitrification by Elemetal Sulfur System). Removing nitrate using sulphur is not complicated at all when enough sulphur is used.
Why carbon dosing? Why make it so difficult and complicated?
A sulfur-denitrator does not need carbon dosing to work! BADESS thus not need daily feeding or dosing.
When it is the idea to make yourselves a carbon-reactor take in mind that a carbon reactor is very difficult to manage and needs daily attention. And no sulphur is needed.
It is best to make a choice between a carbon-reactor and BADESS but not mix the two methods which makes it very complicated.
To reduce high levels of nitrate flow must be able to follow the nitrate level in the system for the reactor to be able to remove more than the daily production. This is very difficult to manage using a carbon-reactor.
BADESS makes reducing high nitrate levels easy as long as the reactor(s) is (are) big enough.

 

[tmz]

I'd rather dose a small amount of CO2 directly (6-10 bubbles a minute, keeping the pH around 6.8) and get some benefit from the calcium reaction while feeding the carbon fixing bacteria.

I don't understand . The bacteria using the organic carbon source(sugar) are heterotrophic ; they have no use for CO2. Running pH at 6.8 will dissolve the carbonate media btw.

 

[rclendan]

The unit was built to specs found at http://reefcentral.com/forums/showthread.php?t=1288082

As far as I know, 1 liter of sulfur per 100 gallons is enough for a recirculating type reactor. I got the idea to dose carbon from http://www.wetwebmedia.com/SulfurDenitratrF.htm Bob Fenner also suggests CO2 addidtion could be beneficial. It will dissolve the aragonite over time, but it can be replenished. The optimal temperature and ph for the denitrification is 32 degrees C and 6.85, so a slightly acidic solution is beneficial.

I understand that the bacteria are carbon fixing and can provide their own food, but my tank water does not seem to contain enough to maintain a good flow with 0ppm NO3. My tank is at approximately 2 ppm NO3 based on the colorimetric reader i made for the APM Nitrate test kit. If i dose carbon i get excellent flow with no trace of NO3 or NO2 In the effluent. As i said there is definitely some reduction in oxygen by aerobic bacteria and that may be causing the unit to become a carbon denitrator.

So i am not sure why my sulfur denitrator has such a low output without carbon, but i am definitely seeing benefits from it even if it is overly complex.

 

[Belgian Anthias]

The unit was built to specs found at http://reefcentral.com/forums/showthread.php?t=1288082

As far as I know, 1 liter of sulfur per 100 gallons is enough for a recirculating type reactor. I got the idea to dose carbon from http://www.wetwebmedia.com/SulfurDenitratrF.htm Bob Fenner also suggests CO2 addidtion could be beneficial. It will dissolve the aragonite over time, but it can be replenished. The optimal temperature and ph for the denitrification is 32 degrees C and 6.85, so a slightly acidic solution is beneficial.

I understand that the bacteria are carbon fixing and can provide their own food, but my tank water does not seem to contain enough to maintain a good flow with 0ppm NO3. My tank is at approximately 2 ppm NO3 based on the colorimetric reader i made for the APM Nitrate test kit. If i dose carbon i get excellent flow with no trace of NO3 or NO2 In the effluent. As i said there is definitely some reduction in oxygen by aerobic bacteria and that may be causing the unit to become a carbon denitrator.

So i am not sure why my sulfur denitrator has such a low output without carbon, but i am definitely seeing benefits from it even if it is overly complex.

As far as I know, 1 liter of sulfur per 100 gallons is enough for a recirculating type reactor. I got the idea to dose carbon from http://www.wetwebmedia.com/SulfurDenitratrF.htm

That is why a lot of users have problems with BADESS. In most cases they do not use enough sulfur to remove the daily production. At low nitrate levels high flow is needed to remove the daily production. For a 100 gal system 1 gal sulfur is needed for easy management.

Fenner never used BADESS. He assumes it could help. Adding carbon is not a good idea.

 

[Belgian Anthias]

The unit was built to specs found at http://reefcentral.com/forums/showthread.php?t=1288082

As far as I know, 1 liter of sulfur per 100 gallons is enough for a recirculating type reactor. I got the idea to dose carbon from http://www.wetwebmedia.com/SulfurDenitratrF.htm Bob Fenner also suggests CO2 addidtion could be beneficial. It will dissolve the aragonite over time, but it can be replenished. The optimal temperature and ph for the denitrification is 32 degrees C and 6.85, so a slightly acidic solution is beneficial.

I understand that the bacteria are carbon fixing and can provide their own food, but my tank water does not seem to contain enough to maintain a good flow with 0ppm NO3. My tank is at approximately 2 ppm NO3 based on the colorimetric reader i made for the APM Nitrate test kit. If i dose carbon i get excellent flow with no trace of NO3 or NO2 In the effluent. As i said there is definitely some reduction in oxygen by aerobic bacteria and that may be causing the unit to become a carbon denitrator.

So i am not sure why my sulfur denitrator has such a low output without carbon, but i am definitely seeing benefits from it even if it is overly complex.

To give any advice I have to know the daily nitrate production in your aquarium system.
Adding carbon is not a normal procedure for using a S-denitrator. Probably your denitrator has not the correct population of bacteria caused by the carbon dosing and that is why it does not work. BADESS works fine at 25°C and a flow of 5l/h/1lS and does not need carbon dosing to work! Because of the carbon dosing your unit acts as a carbon reactor and is difficult to manage. You have to decide if you want to use a S-denitrator or a C- denitrator because they are managed differently.

 

[Belgian Anthias]

The difficulty is in determining the carbon consumption of the unit as not to introduce stray carbon into the aquarium. It is also fiddly to maintain a steady carbon the drip rate. I'd rather dose a small amount of CO2 directly (6-10 bubbles a minute, keeping the pH around 6.8) and get some benefit from the calcium reaction while feeding the carbon fixing bacteria.

Anybody have experience with this? Has anybody tried using CO2 with these units.

BADESS produces CO2. The main reason to aerate the effluent is to get writ of any CO2 left and stabilizing the PH before the effluent enters the main system.
Adding more CO2?
When high daily productions of nitrate has to be removed daily and pure media is used to much calcium may be produced. I advise to use separate reactors for the sulfur and the calcium containing media. it is possible to use one as a calciumreactor adding CO2.
It may be necessary in a low nutrient system but do we need a sulfur denitrator in low nutrient systems?
BADESS works fine at a nitrate level between 1 and 2 ppm. When a lower level has to be maintained flow has to increase. From 1ppm to 0.5ppm flow has to double to remove the same quantity of nitrate daily. PH may not decrease enough to dissolve enough calcium-carbonate. In this case adding CO2 may be one of the solutions for adding more calcium and maintaining alkalinity.
Your reactor works as a C-reactor and PH will not descend without adding CO2. You have to decide which type of reactor is best for your situation and make a choice. Mixing both systems is not advisable.

 

[tmz]

BADESS produces CO2.

How?

This is the reaction from your post #1204:

This is what happens
11 S + 10 NO3- + 4.1 HCO3- + 0.5 CO2 + 1.71 NH4+ + 2.5 H2O

--->

0.92 C5H7NO2 +11 SO4-- + 5.4 N2 + 9.62 H+




CO2 and HCO3 are used by the sulfur bacteria for the C in the organic C5H7NO2 .

 

[tmz]

The optimal temperature and ph for the denitrification is 32 degrees C and 6.85, so a slightly acidic solution is beneficial.

Where did that come from; any data?Haven't heard that before. A qucik seach for denitrification temperature and pH found this:

http://www.wastewaterhandbook.com/d...oval/431_NR_denitrification_prerequisites.pdf

from it:Concerning the influence of pH, it has been establi
shed that there is a maximum
denitrification rate for the pH range of 7 to 8.5,
whereas for pH values smaller than 6 and
larger than 8.5 there is a sharp decrease in the de
nitrification activity.



The denitrification rate increases with temperature until an
optimum is reached at 40 ̊C. At higher temperatures
the denitrification rate is quickly
reduced.

Tends toward basicity not acidity in this reference.

It's pdf so the text is screwy when I copy it over.

Here is another:

http://www.rpi.edu/dept/chem-eng/Biotech-Environ/Environmental/denitrification.html

from it:

[FONT=Arial,Helvetica]Temperature Dependence: Rates of denitrification reactions increase with temperature in a manor similar to what rates in nitrification reactions. They are not as limited in range though, as some bacteria can continue to carry out the processes at temperatures up to 60°C. These bacteria are relatively rare, and as a result reactions are not usually carried out at such high temperatures despite the expected increases in reaction rate. [/FONT]


[FONT=Arial,Helvetica]pH Dependence: The optimum pH for denitrification is in the 7-9 range, with rates falling off sharply outside this region (see figure). At lower pH the generation of N[SIZE=-2]2O and NO is increaced.



again tending twoard basicity.
[/SIZE][/FONT]

 

[Belgian Anthias]

When the effluent is aerated PH will rise and stabilize at the PH of the tank which is a sign of the presence of CO2. Also there is a lot more calcium dissolved as would be possible when only the reaction of the reduction of nitrate was responsible for dissolving the lime. Also the reduction of the free oxygen and nitrification leaves H+ but not enough to explain the quantity of dissolved calcium.
There are a lot of chemical reactions going one in a BADESS. When a fluidized bed is used each of these reactions take place in there own micro environment.
I am pretty sure that BADESS produces CO2.
Maybe a chemist can help out here?!

BADESS works fine at the normal water temperature in the system. I see no practical reason to rise the temperature.

I would not bother a lot over what is going on in the reactors as long it removes the nitrate the way I want. Use reactors that are big enough and give the bacteria the time to grow and adapt to the situation; All one has to do is correct the flow when necessary. Increase the flow when the nitrate level in the system decreases to make it possible for the S-reactor to remove more than the daily production daily until the desired nitrate level is reached. It is simple! But only when enough sulphur is used!

Why doing it the easy way when it can also be made difficult?

 

[tmz]

Th pH would be reduced by the lower alk as 4 units of carbonate alkalinity are consumed per the cited reaction.
The more sulfur you run at high flow the more alk will be consumed via aerobic activity without the benefit anaerobic nitrate reduction. Higher sulfate production than necessary to the process also results. The amount of sulfur needed is realted to the amount of nitrate present .

As for carbon dosing,the facultative heteroptrophic bacteria consume the organic C and do produce CO2.

 

[Belgian Anthias]

Th pH would be reduced by the lower alk as 4 units of carbonate alkalinity are consumed per the cited reaction.
The more sulfur you run at high flow the more alk will be consumed via aerobic activity without the benefit anaerobic nitrate reduction. Higher sulfate production than necessary to the process also results. The amount of sulfur needed is realted to the amount of nitrate present .

.

Based on your quote that the quantity of sulphur is related to the nitrate present can you please answer to the questions: how much sulphur is needed when 30ppm nitrate is present and how much when the level is decreased to 2ppm? How much sulphur will be used to keep the level at 2ppm?

The quantity of sulfhur used has no markable influence on the PH or alkalinity. Only the daily removed quantity of nitrate may change the PH. I suspect ll is compensated by the calcium reactors and passing the effluent true a skimmer. There is not much difference between a reefaquarium with or without BADESS concerning PH, KH and sulphate. The difference in nitrate and phosphate may be noticeable.

Quality brands of salt-mixes contain between 1.8 and 3.3 sulphate. if one has doubts about the sulphate production, use a low sulphate saltmix. I do not bother.

The quantity of sulfur needed is based on the daily to remove quantity of nitrate and the desired nitrate level in the system. It is NOT possible to build a sulfur denitrator that is manageable based only on the present nitrate level in the system.
The basic rule to use a 1% reactor till 50ppm and a 2% reactor above 50 ppm will give a good working and easy manageable sulphur reactor though.

All this was already discussed in previous threads.

What happens when carbon carbonate dissolves in an anaerobic nitrate free environment with a lot of N, H+ and sulphate present ? I do not know, i am not a chemist and I have not the means or the skills to find out.

What I do know is that after many years of use no problems where experienced, not with sulphate production ( probably held back in the calcium reactors), not with alkalinity ( compensated).
Corals where kept in good health for over two years without a water change,


Problems may occur when NOT ENOUGH SULPHUR is used and/or due to mismanagement. Only then H2S formation is possible and/or the reactor will not function satisfactory.

BADESS means a reactor filled with sulphur followed by (a) reactor(s) filled with calcium/ calcium carbonate media and an aeration device ( skimmer) in line.

 

[Belgian Anthias]

Th pH would be reduced by the lower alk as 4 units of carbonate alkalinity are consumed per the cited reaction.
The more sulfur you run at high flow the more alk will be consumed via aerobic activity without the benefit anaerobic nitrate reduction. Higher sulfate production than necessary to the process also results.

BADESS works as a very effective BIO filter while reducing the oxygen. Once praised , now rejected in modern low nutrient reefkeeping. However, BADESS has not the disadvantage of the BIO because the produced nitrate is processed without leaving the system. It does not influence the aquaruim water quality. Even at high flow( 5l/h/lS), due to nitrification ( H+) and denitrification(H+) and other reactions the ph is low enough to dissolve enough calcium carbonate to compensate. This is as long as you feed your animals. I consider this as a big advantage and a huge benefit .

 

[tmz]

This has all been discussed at length beggining back back in the 1200 section of posts. No need to do it again and again.
The "rules" you propose are rigid and make little sense,imo, as noted extensively with great detail in discussions. back in the 1200 section. I disagree with your rule as well as your assumptions and your math pertaining to the amounts per gram etc and about the effects on alkalinity and the bacteiral activity occurring ; no matter how often you repeat the same thing over and over. I still disagree.

Alkainity will be depleted by bacteia that use carbonate for C wether they are engaged in aerobic or anaerobic activity. The O from NO3 is only taken when there is no free O available. With excessive amounts of sulfur for energy and high flow for free O2 very little anaerobic NO3 reduction will occur but the carbonate alkalinity will still be depleted as I see it.

 

[Belgian Anthias]

This has all been discussed at length beggining back back in the 1200 section of posts. No need to do it again and again.
The "rules" you propose are rigid and make little sense,imo, as noted extensively with great detail in discussions. back in the 1200 section. I disagree with your rule as well as your assumptions and your math pertaining to the amounts per gram etc and about the effects on alkalinity and the bacteiral activity occurring ; no matter how often you repeat the same thing over and over. I still disagree.

Alkalinity will be depleted by bacteria that use carbonate for C wether they are engaged in aerobic or anaerobic activity. The O from NO3 is only taken when there is no free O available. With excessive amounts of sulfur for energy and high flow for free O2 very little anaerobic NO3 reduction will occur but the carbonate alkalinity will still be depleted as I see it.

It is OK you disagree with me. It is NOT OK when guidelines are given which do not and can not result in a good working BADESS.
Answering a simple question of how much sulphur has to be used to maintain 2 ppm can not be that difficult when the quantity of sulphur must be based on the 2 ppm nitrate present.
You may disagree with me but I do know how much sulphur I have to use to keep 2ppm in an aquarium system and keep that level. Reactors build following my advice will work satisfactory and never become H2S factories following my operation guideline. BADESS build following my advice have the disadvantage that one may forget the system is there.

All chemical reactions also take place in the main system where no control is possible. Seawater contains +- 2.7 SO4 which means +- .6 S sulphur. Autotrobe nitrification and denitrification may take place anywhere and everywhere where the conditions are suitable and influence PH and KH. What can we do? Remove the Sulphur from the water?
Badess keeps it under control!

People use calcium reactors with CO2?. Kalkwasser? C-reactors? VODKA? What happens when not correctly dosed? Most devices have its pro and cons. I try to minimalise the cons. BADESS does not need dosing.

What is the problem when in practice all is compensated by the system? What is the problem if PH drops till 6.6 when all is compensated before the treated water enters the main system? If alkalinity is effected by BADESS probably other or more calcium carbonate media must be provided. Alkalinity is also effected outside BADESS on which we have no control other than compensate it by other means.
In most cases BADESS has a positive effect on alkalinity because the complete nitrogen cycle is handled by the BADES system and compensated. Using BADESS limits nitrification and this way KH depletion in the main system. BADESS may also produce more carbonate and/or calcium as needed for compensation this way adding to KH and calcium levels of the aquarium system.
Aquaria set up with BADESS where without any water change fore two years without any noticeable effect on corals and animal life.

It is possible to reduce nitrate with 0,5l or 1lit sulphur for each 100gal of system water but do not expect to control the nitrate level with it. This is when the sulphur is used as a base for all bacteria necessary to complete the nitrogen cycle. One can mix sulphur with for example sand or other suitable media but than we have to decide how much. I see no practical reason for making it difficult. Sulphate and alkalinity has for me never been a practical concern using BADESS
When my advice is followed to keep it simple and the simple basic rules are followed the nitrate problem will be solved. Use reactors that are big enough!
The disadvantage of BADESS is that one may forget it is there.

 

[tmz]

I do disagree with almost everything in that post . including your assertion that It is NOT OK.

The question posed is silly since the flow and sulfur amount will vary based on the level of nitrate entering the reactor and different aquariums will produce variable amounts of nitrate related to a plethora of variables.

The biology and chemistry references are almost to much to clear up without unduly moving away from rclendan's question.

For example:

I do know how much sulphur I have to use to keep 2ppm in an aquarium

If that were true there would be no need to keep prescribing excessive amounts of sulfur.

Sulfur reactors are a fine way to reduce nitrate short term or continuously and the obvious negatives( sulfate production and alkainity depeletion) can be minimized ,IMO, rather than ignored.

Sulfate production and alkalinity depletion can be by minimized matching the flow and sulfur content to the amount of nitrate . Higher flow providing more oxygen can prevent H2S if the reactor becomes anoxic and by reducing the sulfur amount in use. The idea that there can't be too much sulfur as stated earlier on is just wrong,IMO. Changing the amount form 1% of water volume to 2% for an extra gallon or two of water volume illustrates how imprecise the "rules" proposed are .

As for nitrification that process occurs in high O2 environments via ammonia oxidizing bacteria.,NO2 and NO3 is produced by this process. However, the NO3 itself contributes alkalinity when reduced via the usual anaerobic bacterial activity which is not the case in a sulfur reactor where additional HCO3 is used.

 

[tmz]

I am experimenting with a 24" DIY recirculating S-Denitrator with a mixed bed consisting of ~1 liter of sulfur prills and ~2 liters of aragonite media. I have a 10 inch cartrige filter holder full of ceramic media plumbed before the unit to add some surface area for aerobic bacteria to consume oxygen and lower the ORP. I have installed some injection ports in the feed line and in the denitrator body so I can feed carbon in the form of sugar solution. I also maintain the unit at 90 degrees F (32 degrees C) for optimal denitrification. when I run the unit without any supplemental carbon, I can only get a relatively small amount of 0 ppm nitrate 1-2 drops per second (< 1 liter per hour) effluent, but when I drip 0.15% sucrose solution at (~15 drops per minute) into the inlet line, I can run the unit at 3-4 liters per hour with 0 ppm effluent. I assume the carbon is either contributing the sulfur denitrating bacteria's biomass, or it is being consumed by aerobic bacteria in the pre-chamber, accelerating the drop in ORP (probably a bit of both), allowing for a higher flow rate. Direct carbon addition also speeds up the cycle (< 1 hour in some cases) when starting, or after opening the unit for cleaning.

The difficulty is in determining the carbon consumption of the unit as not to introduce stray carbon into the aquarium. It is also fiddly to maintain a steady carbon the drip rate. I'd rather dose a small amount of CO2 directly (6-10 bubbles a minute, keeping the pH around 6.8) and get some benefit from the calcium reaction while feeding the carbon fixing bacteria.

Anybody have experience with this? Has anybody tried using CO2 with these units.

I'm interested in your experiment.
While I personally wouldn't add a carbon source to a sulfur denitrator since the heterotrophic bacteria might outcompete the sulfur bacteria and contribute to anoxic conditions that doesn't mean it couldn't work. I have not tried CO2. I'm interested in hearing your results with CO2 and/or adding a carbon source.

 

[Belgian Anthias]

Exessive?!

Exessive?!

I do disagree with almost everything in that post . including your assertion that It is NOT OK.

The question posed is silly since the flow and sulfur amount will vary based on the level of nitrate entering the reactor and different aquariums will produce variable amounts of nitrate related to a plethora of variables.

The biology and chemistry references are almost to much to clear up without unduly moving away from rclendan's question.

For example:

I do know how much sulphur I have to use to keep 2ppm in an aquarium

If that were true there would be no need to keep prescribing excessive amounts of sulfur.

Sulfur reactors are a fine way to reduce nitrate short term or continuously and the obvious negatives( sulfate production and alkainity depeletion) can be minimized ,IMO, rather than ignored.

Sulfate production and alkalinity depletion can be by minimized matching the flow and sulfur content to the amount of nitrate . Higher flow providing more oxygen can prevent H2S if the reactor becomes anoxic and by reducing the sulfur amount in use. The idea that there can't be too much sulfur as stated earlier on is just wrong,IMO. Changing the amount form 1% of water volume to 2% for an extra gallon or two of water volume illustrates how imprecise the "rules" proposed are .

As for nitrification that process occurs in high O2 environments via ammonia oxidizing bacteria.,NO2 and NO3 is produced by this process. However, the NO3 itself contributes alkalinity when reduced via the usual anaerobic bacterial activity which is not the case in a sulfur reactor where additional HCO3 is used.

Which processes take place to deplete the high amount of oxygen in the reactor?

Those who have read my threats know how to calculate the amount sulphur needed. I explained how to calculate the correct amount based on the daily to remove quantity of nitrate and the desired nitrate level. This correct amount is only for de-nitrification when oxygen is depleted. The advised quantity of sulphur is for to be able to complete the nitrogen cycle (nitrification and de-nitrification) at very low nitrate levels and high daily nitrate production which needs high flow.

I do not use exesive amounts of sulphur because the amount of sulphur can not be exessive as the amount has NO or very little influence on the water quality in the main system. There is in total about 750mg to 900mg sulphur present in each Litre of seawater in all its forms, SO4, HS, HSO3, H2S. The sulphur cycle takes place any where where the conditions are suitable, deep sand, stone, hidden places, micro environments and so on. Otherwise BADESS would not work.

We use moving bed reactors to prevent clogging and channelling. The reason why I do not advice to mix the correct amount of sulphur with sand or other suitable base for bacteria I already explained. There is NO practical reason to make it difficult. In a moving bed the substrate moves. When only enough sulphur is added for just the de-nitrification process, that sulphur may not be available on the place where it is needed at the right moment. When only sulphur is used for the complete nitrogen cycle the sulphur is always there where and when necessary. The nitrogen cycle can be completed on that one and the same sulphur particle. On a sand particle this is not possible. When flow has to be changed this has very little influence on the de-nitrification process when enough sulphur is used. When a mixed base is used the reactor is more difficult to manage. We tried this out and the difference is remarkable as we expected?
Not to speak of the problems when the daily to remove quantity of nitrate increases and sulphur has to be added to the reactor. Only experienced users will know when that moment is arrived and act in time. Others will mismanage there reactor and end up with a H2S factory.
That is why I advise what you call " excessive amounts of sulphur"