Nitrate Consumption Rates And Stoichiometry For Organic Carbon Dosing

[Reefering1]

I have not looked at methanol but it is used in sewage treatment as a carbon source. Probably works like ethanol except you need to dose 2 times as much.

Is this the same methanol as in methanol injection on say a drag car? Like windshield washer fluid?

 

[Dan_P]

Is this the same methanol as in methanol injection on say a drag car? Like windshield washer fluid?

I have seen it in windshield washer fluid. I thought nitromethane and one of the nitrogen oxides was used to boost horse power. Maybe methanol is too.

 

[Reefering1]

I have seen it in windshield washer fluid. I thought nitromethane and one of the nitrogen oxides was used to boost horse power. Maybe methanol is too.

So yea, that's the same stuff? Methanol can be useful when injected into the airstream of a force induced engine. As it vaporizes and burns, the evaporation cools the combustion chamber(acting as a fuel), preventing detonation. Street cars might use the washer fluid bottle and spray just before the throttle body "as required".
Now methanol is only a "m" away from ethenol(a known fuel source)...
Am I the only one amazed of all the chemicals and, even fuels, have a place in a reef tank(the most sensitive environment I can think of)??


You chemistry guys might have been on to something...

 

[BeanAnimal]

I have seen it in windshield washer fluid. I thought nitromethane and one of the nitrogen oxides was used to boost horse power. Maybe methanol is too.

Methanol is "Top Alcohol" (4,000 horsepower)
Nitromethane is "Top Fuel" (11,000+ horsepower)

Ohh and the fuel cars don't run 100% nitro - it is in the 90% neighborhood with the rest being methanol. Many reasons, but they run better on less than 100%. A top fuel engine is a marvel of mechanical and chemical wonder - it really shouldn't run or stay together and does not operate like a traditional ICE.

 

[Dan_P]

So yea, that's the same stuff? Methanol can be useful when injected into the airstream of a force induced engine. As it vaporizes and burns, the evaporation cools the combustion chamber(acting as a fuel), preventing detonation. Street cars might use the washer fluid bottle and spray just before the throttle body "as required".
Now methanol is only a "m" away from ethenol(a known fuel source)...
Am I the only one amazed of all the chemicals and, even fuels, have a place in a reef tank(the most sensitive environment I can think of)??


You chemistry guys might have been on to something...

HaHa, much of what we do to our aquaria was first done in sewage treatment, that is more biology than chemistry.

 

[BeanAnimal]

Nitromethane dosing anybody?

 

[Reefering1]

Nitromethane dosing anybody?

I'm pretty sure I'm a few equations away from being able to say "yes"!
I know there has been some methane recently introduced to the room ;-)

 

[Reefering1]

.

 

[Dan_P]

Nitromethane dosing anybody?

Fuel-oxidizer ratio is all about stoichiometry, so, yeah, count me in.

 

[Lasse]

Interesting that the result is in line with many studies of denitrification - adding ethanol was the most effective labile DOC. In this case it could not be denitrification - it must be partly uptake by bacteria growth - partly mineralized

​

A fast reduction the first 5 hours - after that nearly nothing happens in 24 hours - and the control shows a stable concentration - for me it indicate that organic carbon was the limitation factor for bacteria growth the first 5 hours - after that it was consumed or something else become the limited factor. No critic but would not pH values give an idea how much of the DOC that have been mineralized into CO2? As it know - what i understand - your calculation shows how much CO2 is theoretical produced - but is the residue organic carbon as labile DOC (ethanol/Vinegar) or as biomass. Or something between? Can it be that the original DOC is totally consumed and becoming the limited factor again or is something else the limiting factor after 5 hours - space as one possible factor?

The difference in oxygen consumption is interesting - maybe the two different labile DOC favors different bacterial groups with different levels of effectiveness or different element composition . The fact that the P/N ratio for ethanol are 1:20 and for vinegar 1:10 (around) and that O2 demand is nearly 2 times higher (the first 5 hours) for vinegar indicate two different types of bacteria. I know from my time as a waste water worker that there is bacteria groups that are luxury consumers of phosphorus - one example. Interesting in this article is that the surplus PO4 seems to be stored as poly-P and it was induced by using acetate as labile DOC

I think that at least half of the surplus oxygen used by the vinegar experiment is is explained here

With these questions and comments set aside - thank you for a good investigation that - as all good experiment should do - rise a lot of new questions

Sincerely Lasse

 

[Lasse]

Maybe this investigation indicate that vinegar is the best to use if you want a higher removal rate of phosphate when using labile doc in order to grow aerobic heterotrophic bacteria. In the future I will probably test with a reactor filled with coral sand and with a careful dosage of vinegar but I need to bring down my phosphate a little bit more before that. alternative - add small amount of vinegar into my present ethanol dosage into my plenum.

Sincerely Lasse

 

[Dan_P]

Interesting that the result is in line with many studies of denitrification - adding ethanol was the most effective labile DOC. In this case it could not be denitrification - it must be partly uptake by bacteria growth - partly mineralized

​

A fast reduction the first 5 hours - after that nearly nothing happens in 24 hours - and the control shows a stable concentration - for me it indicate that organic carbon was the limitation factor for bacteria growth the first 5 hours - after that it was consumed or something else become the limited factor. No critic but would not pH values give an idea how much of the DOC that have been mineralized into CO2? As it know - what i understand - your calculation shows how much CO2 is theoretical produced - but is the residue organic carbon as labile DOC (ethanol/Vinegar) or as biomass. Or something between? Can it be that the original DOC is totally consumed and becoming the limited factor again or is something else the limiting factor after 5 hours - space as one possible factor?

The difference in oxygen consumption is interesting - maybe the two different labile DOC favors different bacterial groups with different levels of effectiveness or different element composition . The fact that the P/N ratio for ethanol are 1:20 and for vinegar 1:10 (around) and that O2 demand is nearly 2 times higher (the first 5 hours) for vinegar indicate two different types of bacteria. I know from my time as a waste water worker that there is bacteria groups that are luxury consumers of phosphorus - one example. Interesting in this article is that the surplus PO4 seems to be stored as poly-P and it was induced by using acetate as labile DOC

I think that at least half of the surplus oxygen used by the vinegar experiment is is explained here

With these questions and comments set aside - thank you for a good investigation that - as all good experiment should do - rise a lot of new questions

Sincerely Lasse

Thanks Lasse. The experiment surely generated many questions for me. The challenge is answering the right ones to reach my goal: explain why carbon dosing can take a long time or not work at all.

Monitoring pH to correlate with CO2 generation is something I should do. Thanks for the nudge.

Dan

 

[Dan_P]

Maybe this investigation indicate that vinegar is the best to use if you want a higher removal rate of phosphate when using labile doc in order to grow aerobic heterotrophic bacteria. In the future I will probably test with a reactor filled with coral sand and with a careful dosage of vinegar but I need to bring down my phosphate a little bit more before that. alternative - add small amount of vinegar into my present ethanol dosage into my plenum.

Sincerely Lasse

I have one data point for your consideration as you consider your sand experiment

The biofilm generated by vinegar dosing consumes less nitrate than the water per dose. This is in contrast to the biofilm generated by ethanol dosing which consumes as much nitrate as the water per dose. We might keep this mind when comparing data from sand versus water bacteria growth experiments. I have plans on following up this one data point.

 

[Lasse]

We might keep this mind when comparing data from sand versus water bacteria growth experiments.

Have you any evidence that your experiment include pelagic bacteria not only biofilms on the glass? IMO - the only difference between sand and glass biofilm is that the rough surface of the sand has much larger interface area between substrate and oxygen rich water compared with the smooth surface of glass. I mean - if it is only biofilm that are responsible for the action - space could be the limited factor after 5 hours. It could be interesting to run the same experiment but add some more labile DOC after 5 hours.

Sincerely Lasse

 

[Randy Holmes-Farley]

FWIW, I think CO2 produced based on a pH change is going to be a tricky and likely noisy calculation. You will somehow need to account for different buffering capacity as the pH changes. Vinegar will already have changed the pH downward, so it starts at a different (lower) buffering capacity.

 

[Lasse]

Vinegar will already have changed the pH downward, so it starts at a different (lower) buffering capacity.

What I understand now - in the concept for his test was that he add the labile DOC one day before the test started - it means that measuring pH and alkalinity direct before the adding of NO3 and PO4 will give the two values that is needed for calculation of free CO2 according to the program you recommend to me in another thread (CO2SYS),

Taking pH and alkalinity 5 hours after the start of the test and calculating the new CO2 with the program will at least give him a delta CO2.

I have test the Excell version of the program and I feel that it works rather well

In a previous post I said his bottles were C limited when he started the test - that was not correct as he had added DOC a day before the test started - instead the system was N and P limited

Sincerely Lasse

 

[Dan_P]

Have you any evidence that your experiment include pelagic bacteria not only biofilms on the glass? IMO - the only difference between sand and glass biofilm is that the rough surface of the sand has much larger interface area between substrate and oxygen rich water compared with the smooth surface of glass. I mean - if it is only biofilm that are responsible for the action - space could be the limited factor after 5 hours. It could be interesting to run the same experiment but add some more labile DOC after 5 hours.

Sincerely Lasse

The experiment was a simple and crude one. The dosing experiment that I had run for about three weeks was stopped and the water in the experimental container was transferred to a clean identical container. The used experimental container was refilled with fresh Instant Ocean with nitrate and phosphate adjusted to that of the experimental water. I dosed all four containers (2 for vinegar, 2 for ethanol) for about another week.

I am going to redo this experiment, but this time I want to grow the biofilm on something portable rather than the container sides.

 

[Randy Holmes-Farley]

What I understand now - in the concept for his test was that he add the labile DOC one day before the test started - it means that measuring pH and alkalinity direct before the adding of NO3 and PO4 will give the two values that is needed for calculation of free CO2 according to the program you recommend to me in another thread (CO2SYS),

Taking pH and alkalinity 5 hours after the start of the test and calculating the new CO2 with the program will at least give him a delta CO2.

I have test the Excell version of the program and I feel that it works rather well

In a previous post I said his bottles were C limited when he started the test - that was not correct as he had added DOC a day before the test started - instead the system was N and P limited

Sincerely Lasse

I think there are substantial complications that are being ignored, making this a noisy calculation.

For example, acetic acid depletes carbonate alkalinity and lowers pH when first added. An alk test with it there is then complicated because the acetate partly gets measured in an alk test, and partly not, but alkalinity from acetate is not suitable for adding into a CO2sys calculation.

As an example of that, if you compare the CO2sys calculation of free CO2 before and after adding acetic acid with NO time for oxidation to produce CO2, the values will not be the same.

 

[Dan_P]

What I understand now - in the concept for his test was that he add the labile DOC one day before the test started - it means that measuring pH and alkalinity direct before the adding of NO3 and PO4 will give the two values that is needed for calculation of free CO2 according to the program you recommend to me in another thread (CO2SYS),

Taking pH and alkalinity 5 hours after the start of the test and calculating the new CO2 with the program will at least give him a delta CO2.

I have test the Excell version of the program and I feel that it works rather well

In a previous post I said his bottles were C limited when he started the test - that was not correct as he had added DOC a day before the test started - instead the system was N and P limited

Sincerely Lasse

The reason for adding vinegar or ethanol before the test was to get the bacteria past a lag period that lasts at least 9 hours…can’t measure rates with bacteria that aren’t producing. That initial dose is depleted by the time the water sample enters the BOD bottles. At no time is nitrate or phosphate depleted.

 

[Lasse]

Do you add new labile DOC, PO4 and NO3 when the experiment start?

Sincerely Lasse