Nitrogen increase through aeration?

[SteveHman]

I was thinking the other day back to my days in Panama City, sitting through dive physics and remembered some of the basic laws. One thing that struck me is that the air we breath is only 21% O2 and about 78%+ Nitrogen. Nitrogen absorbed in the blood stream causes the bends, so I know it is absorbed into solution.

So I was thinking, does any of that 78% nitrogen that we are pumping through our air stones get absorbed into the nutrient solution?

It would stand to reason that is we are dissolving O2 into solution, then some some Nitrogen must stick as well.

Then I read an article about heavy aeration as a means to remove Nitrogen from waste water in treatment plants. Now I my inital theory is in question.

Do we have anyone with a chemistry background that can elaborate on this? Are we adding Nitrogen through aeration, or does heavy aeration actually remove some of the Nitrogen already in solution? Whatever the numbers are, I am sure that they are very minute either way. Just got my brain thinking.

 

[JJ Bones]

Well...no background in chemistry here, however I'd be interested to find an answer and find some of the greatest discoveries are achieved through intelligent stoner conversation.

That said, my question would be that what is generated via the air-stones isn't exactly the same as the air we breathe, perhaps its almost entirely O2?

On your comment about the air we breathe, have you heard of AZOS? It's a Nitrogen fixing bacteria that allows your plants to ingest Nitrogen from the atmosphere. Great product; reading your intial first sentences it made me think of that for some reason.

 

[SteveHman]

The air coming through the air stones is just the same air we breath that is under pressure. I have a little experience with Air Separation Units (ASU's) and they are massive and require a cooling tower and a whole slough of other equipment to separate out the gases in air.

I know that the Nitrogen in air is not immediately available to plants, they get theirs from the inorganic products in the nutes or from humates in an organic setup.

I checked out the Azos, looks like an interesting product. Might be worth a go.

 

[PrairiePoet]

Also not a chemist and very interested in hearing from any that are.

That said, my question would be that what is generated via the air-stones isn't exactly the same as the air we breathe, perhaps its almost entirely O2?

The air pumps we use do not "generate" O2. They pump air. The air is pumped into the air stones, which comes from the air surrounding the air pump.

So it is the same as we breath.

Well mostly, I guess. There could be some chemical changes to the air if the pump is running at a temperature that could cause chemical reactions to the gasses flowing through it. We could measure the air temp going in the pump, then measure the air temp coming out. I'm doubtful it will be much different.

Otherwise it is the same as we breath.

But back to Steve's post....
From what I can search through, most of the heavy aeration in waste management is also using biologicals to rid the waste water of ammonia. Which is used in agriculture to add nitrogen to crops. But you don't want it in your rivers and lakes. And the aeration seems to be used to help keep the sludge and water mixed better.

 

[SteveHman]

Prairie,
How are things going? Haven't seen you for a while.

Yeah, I know about the waste water/sludge issue using bacteria to break down the ammonia and other nitrates and nitrites.

Ammonia is an interesting chemical and can actually be created through a process using the nitrogen in the air, which is one of the reasons ammonia is used as a base for fertilizers (ammonia nitrate). Easy to make, air is free, just need the industrial plant to make it.

 

[PrairiePoet]

Prairie,
How are things going? Haven't seen you for a while.

Hanging around, but not much else. On week 4 after back surgery. Had two disc's fused. On our last grow with our current setup, hope to harvest in two weeks. Then tear down and we rebuild from scratch. Four times the area we had, and I've been working on my sensor and control DIY unit.

Been watching your grows, very nice.

Light one up and pass it around.....

 

[SteveHman]

Hope you have enough meds to keep yourself out of pain.

I wish I had the room to do a 4X expansion. That is awesome. Make sure to document the DIY project, I like to tinker myself.

 

[PrairiePoet]

Hope you have enough meds to keep yourself out of pain.

I wish I had the room to do a 4X expansion. That is awesome. Make sure to document the DIY project, I like to tinker myself.

More meds than I need (will take) from the pharmacy, Hopefully this harvest will last us till the next one is up and running.

4X isn't hard when you start with 12 sq ft. I do plan on putting up the whole build once I get started on it. I'm laying it out now in SketchUp, and will put the Sensor Controller info somewhere (hardware design, software code).

Here is what I've got so far....

 

[TorturedSoul]

I was thinking the other day back to my days in Panama City, sitting through dive physics and remembered some of the basic laws. One thing that struck me is that the air we breath is only 21% O2 and about 78%+ Nitrogen. Nitrogen absorbed in the blood stream causes the bends, so I know it is absorbed into solution.

The bends (decompression sickness) is caused by dissolved gases coming out of solution into bubbles inside the body on depressurization. IOW, from rising too quickly from the depths that you were at (/ caisson working / flying in unpressurized aircraft above a certain altitude / pressurized mine working / EVA activity from a spacecraft).

Nitrogen - and all other gases - play a part in this, but it's the pressure reduction (and the speed of it) coupled with the depth and time spent at depth that causes the bends in divers. The deeper and/or longer the dive, the more gas is absorbed into body tissue in higher concentrations than normal (Henry's Law). The faster the ascent (and the shorter the interval between dives) the less time there is for absorbed gas to be offloaded safely through the lungs, causing these gases to come out of solution and form "micro bubbles" in the blood.

Nitrogen being absorbed - due to the increased solubility of gases in body tissues, as a result of the elevated pressures at depth (Henry's law again) - does cause nitrogen narcosis.

So I was thinking, does any of that 78% nitrogen that we are pumping through our air stones get absorbed into the nutrient solution?

Likely little of it. Your reservoir is not pressurized and neither are the bubbles (for all intents and purposes).

Some O2 enters the liquid directly through the bubbles, but the majority of it is from the action at the surface of those bubbles bursting (and, to a lesser extent, any activity that disturbs that air-surface interface such as shaking a bottle of water, et cetera; if you've ever had water that had been sealed for a long time and it seemed "off," you could pour it from one glass to another and back a few times to fix it).

It would stand to reason that is we are dissolving O2 into solution, then some some Nitrogen must stick as well.

We are aerating for two reasons, actually: First (obviously), because the roots uptake it. Second, because we are adding more DO than the water generally holds on its own at a given temperature.

There's more to all of it, but I don't think there's a major nitrogen affect on the liquid through aeration. (I could be wrong.)

I did recently glance at an abstract of an article that mentioned something about the effects of water, aeration, et cetera on nitrogen fixation in a nodulated legume (think that was part of the title if you want to go fishing in the Sea of Google for it) that stated the highest fixation of nitrogen in DWC... something something (lol) significantly improved by continuous bubble aeration. But legumes are inoculated with nitrogen-fixing bacteria so I do not know if there would be a direct correlation between them and cannabis. Perhaps if you initially added a packet of the nitrogen-fixing bacteria that is sold in nurseries and garden centers and didn't rush to change your reservoir contents (to give them time to colonize), that would positively affect the nitrogen situation? I have no idea; I do not know if cannabis is the same in that regard. I bought some year before last with the intentions of experimenting (with and without, in soil), but ended up using it in the vegetable garden.

Do we have anyone with a chemistry background that can elaborate on this?

I definitely don't have a chemistry or related background - although I've certainly played doctor many times, lol.

 

[Emeraldo]

am also curious about this, so i googled "plants soil aeration nitrogen uptake" and ran into a 37 year old study that suggests that aeration does indeed promote nitrogen uptake. it's entitled THE INFLUENCE OF SOIL AERATION ON THE EFFICIENCY OF VESICULAR-ARBUSCULAR MYCORRHIZAE. interesting reading!