Anaerobic Bacteria

[BIG-G]

So you would use a meter to determine when to add a carbon source i.e. Vodka / ethanol?
If you were going to try to do this with out any type of meter to measure when to add your carbon source would you start by adding a very small amount say .2 ml per 25 gallon and add this for a week while testing nitrates and if no decrease is detected increase the dose by .1 ml and repeat.
If I remember correctly from dosing my reef back years ago that is how you start out dosing.
I assume this would need to be done to the whole system. Is this wrong? Or
Should you dosed directly to the line running into the denitrifying towers? I would think this could effect the bacteria negatively but I don't know this for sure.

 

[jaws7777]

So you would use a meter to determine when to add a carbon source i.e. Vodka / ethanol?
If you were going to try to do this with out any type of meter to measure when to add your carbon source would you start by adding a very small amount say .2 ml per 25 gallon and add this for a week while testing nitrates and if no decrease is detected increase the dose by .1 ml and repeat.
If I remember correctly from dosing my reef back years ago that is how you start out dosing.
I assume this would need to be done to the whole system. Is this wrong? Or
Should you dosed directly to the line running into the denitrifying towers? I would think this could effect the bacteria negatively but I don't know this for sure.

Great questions i would also like to ask what happens if you miss a dos or two..or three or a whole week lol

 

[jaws7777]

Truth. And see below.



I looked this up in a text book and learned that biological denitrification (i.e. denitrification by aerobic and/or anaerobic bacteria) requires carbon as the electron donor... catalyzing the reaction from NO3 to N2 yields carbon for the bacterium in question. In a previous post I suggested DOM (dissolved organic matter) could serve as an electron donor in denitrification. While this is true for denitrification in general, it is not true for biological denitrification. DOC (dissolved organic carbon) is a subset of the larger mass that is DOM.

Why would DOM be a an electron donor in general dentrification but not in biological dentrificarion ? Biological dentrification meaning the conversion from N0-2 to N03 ? Or the N0-3 ro N02 (nitrogen dioxid) conversion.
I just want to make sure im following appreciate the explanation.

How effective could this be long term without dosing with a carbon source ?

 

[BIG-G]

Well with salt you just pick up the next day where you left off. I'm thinking the only thing that you had to worry about was a bacterial bloom making the water cloudy if you OD. But all my experience is with salt I can't say for freshwater

 

[Grinch]

So you would use a meter to determine when to add a carbon source i.e. Vodka / ethanol?
If you were going to try to do this with out any type of meter to measure when to add your carbon source would you start by adding a very small amount say .2 ml per 25 gallon and add this for a week while testing nitrates and if no decrease is detected increase the dose by .1 ml and repeat.
If I remember correctly from dosing my reef back years ago that is how you start out dosing.
I assume this would need to be done to the whole system. Is this wrong? Or
Should you dosed directly to the line running into the denitrifying towers? I would think this could effect the bacteria negatively but I don't know this for sure.

The dosing regimen you've outlined is a better safe than sorry approach for dosing blind (without a meter). I've done some internet sleuthing and I can't find anything to support ORP as a measure of DOC, which makes me think that there is a poor correlation between the two (not surprising)... so I think I'm going to have to retract my ORP suggestion completely as it applies to bacterial denitrification in a fish tank (fresh or salt). Measuring DOC is going to be way to expensive for the typical hobbyist, so I'd stick with something like the above method.

As for WHERE to dose, that's a tricky question. Turn-over rate through the filter, pH, pE (ORP), temperature, salinity, and dissolved oxygen all have roles in the decomposition and reactivity of DOC as electron donors in denitrification.

Great questions i would also like to ask what happens if you miss a dos or two..or three or a whole week lol

Think of DOC as the spoon that allows denitrifying bacteria to eat NO3 soup. If you take away the spoon all the bacteria have to eat the soup with is a fork. With a fork, the bacteria don't get as much soup. Keep the spoon away for long enough and they'll starve... the colony will decrease in size. In practical terms, your denitrate filter will lose efficiency.

Why would DOM be a an electron donor in general dentrification but not in biological dentrificarion ? Biological dentrification meaning the conversion from N0-2 to N03 ? Or the N0-3 ro N02 (nitrogen dioxid) conversion.
I just want to make sure im following appreciate the explanation.

In naturally anoxic waters/soils there are LOTS of redox reactions that can occur that are not mediated by living organisms. These include "abiotic denitrification" or "chemodenitrification". The end result is the same as in biological denitrification: going from NO3 to N2. There is also a biological denitrification pathway that follows NO3 to NO2 to N2O. I believe there is a third pathway as well, but I'm not remembering it off hand.

 

[BIG-G]

The dosing regimen you've outlined is a better safe than sorry approach for dosing blind (without a meter). I've done some internet sleuthing and I can't find anything to support ORP as a measure of DOC, which makes me think that there is a poor correlation between the two (not surprising)... so I think I'm going to have to retract my ORP suggestion completely as it applies to bacterial denitrification in a fish tank (fresh or salt). Measuring DOC is going to be way to expensive for the typical hobbyist, so I'd stick with something like the above method.

As for WHERE to dose, that's a tricky question. Turn-over rate through the filter, pH, pE (ORP), temperature, salinity, and dissolved oxygen all have roles in the decomposition and reactivity of DOC as electron donors in denitrification.



Think of DOC as the spoon that allows denitrifying bacteria to eat NO3 soup. If you take away the spoon all the bacteria have to eat the soup with is a fork. With a fork, the bacteria don't get as much soup. Keep the spoon away for long enough and they'll starve... the colony will decrease in size. In practical terms, your denitrate filter will lose efficiency.



In naturally anoxic waters/soils there are LOTS of redox reactions that can occur that are not mediated by living organisms. These include "abiotic denitrification" or "chemodenitrification". The end result is the same as in biological denitrification: going from NO3 to N2. There is also a biological denitrification pathway that follows NO3 to NO2 to N2O. I believe there is a third pathway as well, but I'm not remembering it off hand.

Would the other path be from Nh4 ?

 

[Grinch]

Would the other path be from Nh4 ?

You just had to make me google it, didn't you

There are three pathways to get gaseous nitrogen in denitrification... the end results being N2, N2O, or NO (this is the one I was missing) respectively.

Maybe you are thinking about ANAMMOX? (ANaerobic AMMonia OXidation). This is not denitrification, but the end result is similar with respect to a fish tank and the goal of removing wastes. I've never heard of anyone trying to using ANAMMOX to clean a fish tank........... someone needs to step up and be first!

 

[jaws7777]

The dosing regimen you've outlined is a better safe than sorry approach for dosing blind (without a meter). I've done some internet sleuthing and I can't find anything to support ORP as a measure of DOC, which makes me think that there is a poor correlation between the two (not surprising)... so I think I'm going to have to retract my ORP suggestion completely as it applies to bacterial denitrification in a fish tank (fresh or salt). Measuring DOC is going to be way to expensive for the typical hobbyist, so I'd stick with something like the above method.

As for WHERE to dose, that's a tricky question. Turn-over rate through the filter, pH, pE (ORP), temperature, salinity, and dissolved oxygen all have roles in the decomposition and reactivity of DOC as electron donors in denitrification.



Think of DOC as the spoon that allows denitrifying bacteria to eat NO3 soup. If you take away the spoon all the bacteria have to eat the soup with is a fork. With a fork, the bacteria don't get as much soup. Keep the spoon away for long enough and they'll starve... the colony will decrease in size. In practical terms, your denitrate filter will lose efficiency.



In naturally anoxic waters/soils there are LOTS of redox reactions that can occur that are not mediated by living organisms. These include "abiotic denitrification" or "chemodenitrification". The end result is the same as in biological denitrification: going from NO3 to N2. There is also a biological denitrification pathway that follows NO3 to NO2 to N2O. I believe there is a third pathway as well, but I'm not remembering it off hand.

Ok dumb question then...carbon dosing = DOC = spoon.

Since im not dosing i have no spoon = lower chances of success rate ?

Or

Since DOC is a subset of DOM then do i possibly have the spoon lol ?

 

[BIG-G]

Yes you are correct
I was referring to ammonium being converted through the denitrifying process.

 

[Grinch]

Ok dumb question then...carbon dosing = DOC = spoon.

Since im not dosing i have no spoon = lower chances of success rate ?

Or

Since DOC is a subset of DOM then do i possibly have the spoon lol ?

Your likelihood of success would be increased with DOC dosing in some manner, but it may not be necessary.