Reef Chemistry Question of the Day #54 Denitrification

[Randy Holmes-Farley]

"organics + O2 --> CO2 + H2O + energy"


Doesn't this mean that A is also right?:smile:

The CO2 is on the product side, so it is produced in the reaction, but I wouldn't have said it is "needed for the process to take place".

That would be like saying CO2 is needed for a fire to burn, but few people would claim that.

Still I see you may think it is an unfair semantic difference. But life isn't always fair.

 

[Cory]

Some bacteria performing denitrification apparently do use bicarbonate, although I didn't read the whole article:

Effect of carbon dioxide and bicarbonate as inorganic carbon sources on growth and adaptation of autohydrogenotrophic denitrifying bacteria | Kheireddine Taieb Aroua - Academia.edu

 

[Cory]

I meant to post this:

Effect of carbon dioxide and bicarbonat... - PubMed Mobile - NCBI

 

[Randy Holmes-Farley]

I meant to post this:

Effect of carbon dioxide and bicarbonat... - PubMed Mobile - NCBI

Those bacteria are metabolizing hydrogen gas instead of organics. I don't know if that happens in reef aquaria since I'm not sure where the hydrogen gas would come from.

 

[Cory]

Yeah it would probably need electrolosis of some sort.

 

[DFW]

Those bacteria are metabolizing hydrogen gas instead of organics. I don't know if that happens in reef aquaria since I'm not sure where the hydrogen gas would come from.

My display tank has a plenum under 2/3 of the deep sand bed. What gases, if any, might be down there?

 

[Randy Holmes-Farley]

My display tank has a plenum under 2/3 of the deep sand bed. What gases, if any, might be down there?

N2, carbon dioxide, ammonia, hydrogen sulfide. Only N2 would actually present as a gas rather than be dissolved.

 

[beaslbob]

And the answer is...C. Organics (although B would also get credit for the ammonox process, see below)

...

Dern

you mean I guessed right?

WOW!!!!!

even a broken clock tells the correct time twice a day.

 

[Cory]

Would electrolosis produce bad things in a reef Randy? Let's assume that hydrogen wasn't enough to explode.

 

[Russellaqua]

A would be incorrect because CO2 is not required, but is a product of the process.

 

[DFW]

N2, carbon dioxide, ammonia, hydrogen sulfide. Only N2 would actually present as a gas rather than be dissolved.

Some of that does not sound like I would want it under there!

 

[Randy Holmes-Farley]

Would electrolosis produce bad things in a reef Randy? Let's assume that hydrogen wasn't enough to explode.

Electrolysis could produce chlorine (Cl2), so yes, it can be bad. Are you thinking of doing it?

 

[Randy Holmes-Farley]

Some of that does not sound like I would want it under there!

Well, I'm not saying how much or even if they are necessarily all there, but there are processes that could make all of those.

 

[Cory]

Electrolysis could produce chlorine (Cl2), so yes, it can be bad. Are you thinking of doing it?

I was thinking of doing it provided there is nothing bad. I'd seen electrolosis of wastewater, can't remeber which materials for the cathode and anode, I think iron, but it removed po4 at an efficient rate.

My other idea, and nobody better steal it, was to use piezoelectric sand to produce small amounts of hydrogen gas to facilitate possible denitrification via bacteria that use it, but I'm not sure if saltwater had those kind.

 

[Randy Holmes-Farley]

I've not heard of piezoelectric sand, nor do I have any idea what (if anything) it might do in a conductive medium like seawater.