Increasing DO

[Oliver]

Re-posted from private messages

thechaossmurf

ok I got an idea that literally might blow up in my face --so I thought id ask u if u know if anyines tried it yet ----
im going to be building a homemade oxygen & hydrogen separator to fuel another experiment that im needing the hydrogen ----so I was wondering if I could pupe the unwanted oxy inot my air pump to add extra oxygen to my aquaponics system --granted it wont be insanely huge amounts ---but do you think itd make the air pump go boom ??? ---feel free to repost this onto the site if you want ---I didn't know where to put it at so I sent it too you

Oliver: "First, please do not use private message for your questions. They need to be shared with everyone on the forum.

"I see no reason why it would not work. What kind of separator are you using? I've been thinking of doing this myself."

thechaossmurf "Oliver im going to be using a home-built oxygen separator design --basically a you-tube design I found somewhere ---my main question was if there is any chance of an explosion from an air pump if it had a tad extra oxygen in its intake though && honestly I got no idea where to post it at here"

[Oliver]

It should work, but as you say, depending on the amount of O2 will determine how much increased DO you get.

Oliver

[David - WI]

Have you seen this: https://youtu.be/IOuGQ6TEDFk

IOuGQ6TEDFk

[Oliver]

Thanks,

Interesting, pricey and power consuming.

Oliver

[Jason]

I have to agree with Oliver. I checked out their website and was shocked at the price of the units. Very pricey, but hopefully will come down with time. It would be interesting to see if the initial price and cost to operate could be offset by increased growth.

Jason

[Oliver]

Also,

What happens to the hydrogen that is generated in the electrolysis process? Is it also absorbed in the water as well as the O2, and how does that affect the pH?

Oliver

[David - WI]

Just gasses off according to the faqs. I imagine that electrode could be at/near the surface in most cases?
I'm not promoting it, I just thought it would be a useful site for the OP/e-mail person.

[Oliver]

I think a better way would be to do the electrolysis externally, as thechaossmurf is suggesting. That way you could place the aerators in deeper water, allowing for better absorption of the O2 as the water pressure is a factor in amount of absorption. Also, probably at a lower equipment cost.

I was a little surprised at the small amount of increase in DO they were getting, as I thought it would be higher. Although, I am not familiar with the use of pure O2 in that application, so I don't have a reference for my metric.

What I see are fine bubbles of H2 and O2 (assumed) to be rising up and out of the shallow water and escaping into the atmosphere. Not sure why the H2 would not be absorbed along with the O2. The deeper the water the more pressure at the bottom, which translates into more exchange of gas into the water and a longer time to the surface allowing for more contact of the bubbles' surface with the water, and again, more gas exchange.

By the way, a misnomer I detected early on in my Aquaponics learning curve. When the term "surface" is used regarding aeration it does not mean the surface of the water in the fish tank, it means the interface of the surface of the air bubbles with the water they are rising through. So, placing the aerators on the surface of the water in the fish tank is the worst and least effective place you can put them. Even though it may break the surface tension of the surface of the water by placing them at the top of the water, it does little good for adding DO to the water in the tank. For that, you need depth.

You don't need a 6 foot deep fish tank but you do need a tall tower, which can be just a relative large diameter (say 4 to 6 inches) of pipe standing on end with an aerator in the bottom and an air pump capable of pushing air that deep. Just flow the water through the pipe by pumping it into the bottom and letting it overflow out the top and back to the fish tank or directly into the grow beds or wherever. With that configuration, the water coming out the top of the pipe will be super saturated with atmospheric gases, including O2, or just pure O2 as suggested above.

More to chew on,

Oliver

[David - WI]

Normally in electrolosys one electrode produces hydrogen and the other oxygen, so I suggested putting the hydrogen producing electrode closer to the surface o it would gas off more readily.

[Oliver]

David,

Yes, you could do that. However, you would then have electrical current traveling between the electrodes. If you were to shield the configuration so no fish could swim in between, or place it in another water container, it could the be answer to put more O2 in the water than H2.

The greater the distance between the electrodes, the greater the voltage for the same current. Although, there is something called ohms per square, and in this case ohms per cube. It suggests that regardless of distance on the surface of a conductor, such as a sheet of copper (ohms per square), that the resistance doesn't change with distance. Maybe with three dimensions, as in a tank of conductive water, the resistance would actually decrease with distance, requiring less voltage the further apart the electrodes. Just a thought.

Good idea, though,

Oliver

[thechaossmurf]

oliver id love to see how to test the idea of separating the electrodes ---without zapping a fish --I was thinking in a bubble tower type setting

and yeah I was definitely talking about HOME-MADE SEPERATOR --THEN JUST PUTTING THE OXYGEN OUTPUT RELATIVELY CLOSE (POSSIBLY ATTACHED TOO) TOO MY AIR PUMPS INTAKE --omg I hate caplock grrr --- im guessing that if I pumped PURE oxygen into the air pump itd be more dangerous than just putting it a millimeter away so its all going into pump --but at least some regular air goes in also -- to dilute the oxygen saturation inside the airpump----- another idea ive had is --juts cll the manufacturer and ask if theres any spark chance inside their air pump--and let them know id be running pure oxy into it & see what they say ???

[David - WI]

Actually you could just put both electrodes at the bottom of the tank and place an open tube above the hydrogen electrode to keep the hydrogen from mixing with the tank water. The bubbles would all rise through the same small column of water and exit at the surface.

I just thought it was relevant to the original post, I have no intention of buying it. I'm actually building a PSA oxygen concentrator as we speak that should produce (up to) 120 L/min of 95% pure oxygen. :D

[thechaossmurf]

well my variation on the design is going to have a bell or cone above the hydrogen electrode ---with a small diameter pipe going up & out of the area (house ,greenhouse,building) that way the hydrogen gets vented away from the fish as much as possible ----it will be piped to the generator to help power it for electricity returns ---so basically the system will almost power itself ----I was also trying to design a way to run the generator on woodgas & hydrogen combo ---that way the only fuel would be wood chips from a local treeservice & the extra explosive power being fed into the generator would come from the hydrogen ---since woodgas has like half the punch of gasoline --im hoping the hydrogen will get the power back up there closer to a gasoline powered generators capability ????

[thechaossmurf]

hey david ---any chance you can show us pics or a video of your current progress ???

[thechaossmurf]

another concern ive had is --if you put the electrodes into the actual aquaponics system as opposed to just ajug of water that is sacrificed to separation is ----with the current fry the bacteria in the water with the electricity flowing between electrodes-- in sufficient amounts that it will start effecting the systems ecology ----because its pointless too increase the oxygen in the water to boost plant and bacteria growth (IF) we kill off the bacteria ata greater rate than they are reproducing ?? ---soo if it does fry bacteria faster than they making more bacterias it might be better off to have a totally separate water source for the electrodes to be in --then pump the oxygen into the aquaponics system ---anyone got the brainpower to think up HOW to test that situation ?

[David - WI]

My military surplus oxygen concentrator modules just came today ( weighs 560 pounds I think) and I'm still waiting for filters & parts for the 15hp air compressor I bought a couple weeks ago. I have to build the control mechanism and get it all plumbed up... but I'll try to post something soon.

[thechaossmurf]

ow man david --pictures :) hehehe you got my brain wondering hat monster machine ya building :) show us what progress you've made --even lack of progress :)

[David - WI]

Not much to see yet, I have parts arriving daily... valves, fittings, timers, etc.

It's a Mattei air compressor, Zurn refrigerated air dryer, and a large array of zeolite filled PSA canisters.

5018 5019

[David - WI]

Finally got all the oil & air filters so I could fire up the compressor... I was concerned about the environment it came out of especially that it may have been overheated so the oil turns to varnish and plugs the oil cooler. Seems to be OK: https://m.youtube.com/watch?v=mFeuywK35lE

The thermal image shows (what appears to be) hot oil going through the cooler and coming out... cooler. :D

It's not much to watch, the rest of the plumbing won't be here until Monday so I'm working on other stuff. Still, it's hard for me to picture 2 liters per second of almost pure oxygen coming out 24/7. :eek:

[thechaossmurf]

dang david -wi ,,what kinda aquaponics setup you have that's going to burn through that much oxy ???? id think if you put tooo much oxy into a system it will do more harm than not boosting it ?????? ----then again I guess ya can always just pipe a lot of it into your home or just out the roof ??? or endless other uses for spare oxy :)
any chance ya can throw a few pics of your total system ??? I imagining several greenhouses filled to the brim :)

[David - WI]

There won't be any greenhouses, it will all be "indoors"... but I'm still building. We'll probably only need 1/2 the oxygen but I wanted to be able to "expand" without having to buy another whole 02 system.

[thechaossmurf]

a greenhouse qualifies as indoors :) hehehe but id love to see what all ya doing there man ---ive got huge dreams & other peoples builds help me dream bigger :)

[David - WI]

I'll try to send you a personal message tomorrow with some info, but don't expect as much inspiration as frustration from me... this has become​ a long, slow project.

[thechaossmurf]

well if ya think its long and slow --imagine doing it with zero spending dollars to even start the dream and no land to place it on :( ---hence why my plans are all (most) in the dreaming & planning stages :(

[David - WI]

Yeah, I've scrounging as much as I can instead of buying everything new, but it's still adding up to a lot of money.

[JCO]

Oliver, if you are still kickin', email me at info@sparetimepublishing.com. JCO