Plenums and the wasting "option"

[barryhc]

Originally posted by reefclown
OK, hopefully misunderstanding cleared up and we are on a CLEAN SLATE.
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so in effect rather than the 1000 microns you mentioned earlier a more realistic target figure MAY be in the range 10-300 microns ? everything below 300 microns being anaerobic. Add degradable organic matter to the above equation and the nitrifying layer will reduce yet further?

I hope this goes someway to explaining why the above does not still well, and hopefully open up the discussion in the areas you intended.

Thanks for the reply, ReefClown, you are quite gracious. I think that these processes are actually occuring at both ends of this spectrum, but it is where they "predominate" that I have been putting emphasis on. You can tell now, that I have been more interested in bacteria than anything else, since the thread started. The mechanics, just aren't that difficult.

All questions need to be answered, just the same. I hope everyone understands that I DO NOT KNOW IT ALL HERE!!!

I will know enough by Christmas, when my 200-300 gal. tank goes in.

ReefClown, our replies have "passed during typing". This happens fairly often. Consider my last post, I wrote it before I saw "your last", so it is not "in response". I am a slow typer.

I have to leave right now, not enough time to really respond, I will read, consider, evaluate and respond, possibly by tommorow.

Thanks for joining us here, learning is the goal.

> barryhc

["Umm, fish?"]

Hey! I finished roughing out my grid tonight! Now I just need to put my drill press together that showed up today and make some holes!

You gotta love Amazon. A 95 lb. drill press. It qualified for free shipping because of the price and they lived up to it. Delivery to my porch, absolutely free!

I would like to run O2 and/or pH probes, but my understanding is that these probes only last so long before needing cleaning and or replacement, and "servicing" the probe, would disturb the environment were trying to monitor.

What do you think about running a piece of pvc with ID large enough to hold the probe down through the sand layer; holes for water flow only at the bottom (inside the bed); cap on top with a hole drilled for the probe wire?

The probe can be taken in and out with minimal disturbance of the bed.

As for the micro plenum water sampler, I don't see what benefit you gain over just testing the waste water. I was thinking that some sort of probe might give you a idea of when you need to waste before you suck water out. If you used a controller with the probe you might be able to automate the whole thing.

Happy weekend!

[salty joe]

Hi Barry,
You asked a while ago if I had put a carbon cap on the collection pipe. Unfortunately, I am in the planning stages and will be there for quite some time.
The discussion on testing the effluent is interesting. Your idea of taking water from different parts of the plenum to see what happens after a draw is an excellent idea.
Am I off-base for thinking that testing for phosphate in the effluent will tell the story? I was thinking that once consistent phosphate readings were achieved, a balance had been struck and the sand bed could last indefinitely. Or am I all wet?

I also wonder if a less scientific test of the effluent would be useful. Like maybe get a vial of effluent and check it for color against a color chart. Maybe even notice if the smell is different.

Anyway, I find this thread very interesting and now I will go back to the lurking mode.
Joe

[reefclown]

Been thing about the 'pull' mechanism, and thought about an old reverse flow sand filter design from Frank De Graaf in the 70's that could be adapted to provide a simpler mechanism.

here's a sketch of an adaption.




It removes the need for a manifold and should allow for an even pull through the sediment bed. The pull pipe can be placed at any depth and simply tapped.

any thoughts?

[barryhc]

Originally posted by "Umm, fish?"
What do you think about running a piece of pvc with ID large enough to hold the probe down through the sand layer; holes for water flow only at the bottom (inside the bed); cap on top with a hole drilled for the probe wire?

The probe can be taken in and out with minimal disturbance of the bed.

As for the micro plenum water sampler, I don't see what benefit you gain over just testing the waste water. I was thinking that some sort of probe might give you a idea of when you need to waste before you suck water out. If you used a controller with the probe you might be able to automate the whole thing.

I don't think I can get good oxygen information from the waste water, and I want to monitor many parameters, at many depths and locations CHEAPLY. The "micro plenums" cold cost as little as $20 for about 28 0f them. I might actually use that many.

This idea is not for the average installation of one of these systems, but is instead, only for me to learn about what is going on for both my, and everyone's benefit.

Having one probe mounted in a fashion similar to what you propose, for the pupose of automation, may be a good idea, if we can find a probe that will last long enough, when continuously submerged.

Thanks, > barryhc

[barryhc]

Originally posted by salty joe
Hi Barry,
You asked a while ago if I had put a carbon cap on the collection pipe. Unfortunately, I am in the planning stages and will be there for quite some time.

I was particularly enjoying the progress we were making then, on the "cheap-simple-automated-volume" control. I like the system that had developed at that point, with one caveat, for me anyway. That is that I remain somewhat adamant about "high flow", and that set-up is going to slow down to "zero", in a linear fashion, and that is a concern for me. I haven't thought about it since, to solve that problem, but it remains on my "burner".

Last I remember, we had "no-stink", and adjustable automated volume, "on the cheap" and easy.

The discussion on testing the effluent is interesting. Your idea of taking water from different parts of the plenum to see what happens after a draw is an excellent idea.
Am I off-base for thinking that testing for phosphate in the effluent will tell the story? I was thinking that once consistent phosphate readings were achieved, a balance had been struck and the sand bed could last indefinitely.

I am interested in Phosphate, pH, and oxygen primarily, the "micro plenum", or whatever we call it, lets us test for anything-anywhere-anytime, so to speak.

I am very much in the planning stages for my "big tank". You needn't "lurk" so deeply, come up for "oxygen" more often!

> barryhc

[barryhc]

Originally posted by reefclown
Been thing about the 'pull' mechanism, and thought about an old reverse flow sand filter design from Frank De Graaf in the 70's that could be adapted to provide a simpler mechanism.

It removes the need for a manifold and should allow for an even pull through the sediment bed. The pull pipe can be placed at any depth and simply tapped.

any thoughts?

I don't see where this is very much different than an under gravel filter plate. It could be made to work with some modifications for better flow balancing. Drill holes in the bottom plate, or elsewise cause a "flow restriction" between "above and below", then cover with egg crate and screen to "disperse" the draw between the lower plate and screen. The restriction is crucial to balanced flow, and still requires high flow to "effectively balance".

Thanks all. >barryhc

ooPS: I haven't had time to review on bacteria, but it remains my highest interest, along now, with post installation "testing".

[reefclown]

Sediment composition aside, would it be fair to say that:

A plenum in it's basic mechanical sense in an undergravel filter with a broken airlift?
A wasting plenum is akin to an undergravel filter whereby the passing of water through the sediment bed is "controlled and wasted" rather than continuous and recycled ?

If

1.the screen and sediment composition is as you propose in your current design,
2.the plenum void space is also the same,

then the shown diagram simply equates to replacing the manifold with a tap, right ?

I'm trying to get my head around how adding a manifold improves the dynamics of waste extraction and can't quite grasp it at this moment. Am I missing something fundamental ?

["Umm, fish?"]

Actually, having a plenum void space around the manifold might be the best best. There'd be no sand around the manifold to impede the draw. That said, I don't think I'll bother, for reasons stated farther up the discussion.

[barryhc]

Originally posted by reefclown
Sediment composition aside, would it be fair to say that:

A plenum in it's basic mechanical sense in an undergravel filter with a broken airlift?
A wasting plenum is akin to an undergravel filter whereby the passing of water through the sediment bed is "controlled and wasted" rather than continuous and recycled ?

That is very close, in a "basic look" at the function.

If:

1.the screen and sediment composition is as you propose in your current design,
2.the plenum void space is also the same,

then the shown diagram simply equates to replacing the manifold with a tap, right ?

Yes, the diagram replaces the manifold with a tap, and that does not represent a problem in itself, BUT, it is not that SIMPLE.

I'm trying to get my head around how adding a manifold improves the dynamics of waste extraction and can't quite grasp it at this moment. Am I missing something fundamental ?

Yes, It is not the manifold itself that is important here, it is that the manifold was designed with a "restriction" that is created by the total area of the holes, relative to the area of the plenum piping I.D..

If you will review the previous post carefully, you will see that I explained how this restriction could be designed into the system that you offered, and that it could be made to work in this way.

It could possibly, even be a better design, in the end, IF restriction is utilized with high flow, and short duration, to achieve "flow balancing". Else-wise, "channeling" will occur, and "control" over the bacteria populations will be lost.

I hope this helps, I'm still trying to keep up with the bacteria discussion that got "dropped", from a few posts ago.

> barryhc

[barryhc]

ReefClown, I have finally gotten around to reviewing your information on "bio-film thicknesss".

Originally posted by reefclown
The thread appears to be evaluating a method of controlling bacterial activity within a sediment layer. And the core of the discussion looks at the effects of bacterial activity within that sediment under varying circumstances.

I was simply meaning to ask what activity you believe occurs at a smaller scale, for example on the bacterial film that coats a single grain of sand. Is this bacterial film capable of completing the full nitrogen cycle. i.e does the bacterial film covering the grain of sand contain aerobic, anoxic and anaerobic zones/bacteria within it?

Quote, from your link:The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 µm below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S0) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms (approximately 1,500 µm), which accounted for about 75% of the total S pool in the biofilm.?

>> 1,500 µm is 1.5mm which is 1/16". ( "thin wastewater bio-films" )

Quote, from your link:Therefore, successive vertical zonations of predominant respiratory processes occurring simultaneously in close proximity have been found in aerobic wastewater biofilms with a typical thickness of only a few millimeters

>> A "few millimeters" = 3mm = 1/8". ( typical thickness )

Quote, from your link:Composite DIC image of the entire biofilm vertical section (scale bar = 200 µm). The biofilm thickness is about 1,500 µm.

>> Again, 1,500 µm is 1.5mm which is 1/16".

I did not think that you were questioning my understanding of distances, I was questioning yours.

I'm simply asking you to consider a lower denominator, as it may aid in the understanding of how the sediment will operate when the oxygen gradient changes.

so in effect rather than the 1000 microns you mentioned earlier a more realistic target figure MAY be in the range 10-300 microns ? everything below 300 microns being anaerobic. Add degradable organic matter to the above equation and the nitrifying layer will reduce yet further?

If we can come to some agreeable understanding of various bio-film thicknesses, then we might be able to make some progress on bacterial population discussions. I am looking forward to it.

Let's start. I think that the point that is being made, about the bio-film, is that the surface of the "bio-film" is aerobic to begin with, such as would be the case, where algae on a surface, feed nutrients to the aerobic bacteria at the surface of the bio-film, which nutrients are then processed by the aerobic bacteria, into "food-stuffs" for the bacterialogical populations that are "deeper in" the bio-film.

I think that this MAY BE more predominant, in thicker bio-films, that are being fed with "solids", and less likely in "thinner populations that recieve their food from dissolved nutrients. Especially so, where these bacteria live in a "zone", that is not entirely "stagnant".

I don't believe in allowing detritus, fish poop, etc. , to collect at the substrate surface, and it does not occur in my current tank. So, I have not been looking at this system having to deal with high loads of undissolved solids, but more on the basis of dissolved nutrients, that are "common" to the water column, as a whole.

I think in terms of the "lower denominator", I have been thinking in terms of bacterial "films", if you like, that are as thin as 5 microns, or 5 µm, in the "Aerobic" upper layer of the substrate. I suspect that these "upper bacterial populations" would remain "thinner", because the water is not being allowed to become stagnant. This would only be true, of course, for the "High Frequency" type of plenum wasting.

I further suspect, that these "films" could become somewhat thicker, deeper in the bed, in the "Anaerobic zone" ( below 1-2" ) because "upward diffusion" is probably less predominant in this area, and is partially responsible for the "sinking" that is so commonly referred to in "DSB discussions".

How is that for a "restart" on bacterial discussion?

> barryhc

[barryhc]

Ok, for those who might "pop-in" here, and can't deal with reading the whole thread, which is getting lengthy, and for any who might have forgotten the emphasis of this endeavor, I am including an excerpt from another discussion, that offers a reasonably short summary, of at least my own objectives.

Here you go.

quote:
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The idea of a biofilm protecting the anaerobes is an intriguing one--but if these are strict anaerobes, to which oxygen is toxic, the biofilm will gradually erode as the uppermost layers are exposed to oxygen and die and decay away. Of course if we are dealing with "facultative anaerobes" this is not the case because these bacteria can live with or without oxygen. Being as no one has a great idea of what bacteria are at work here I would hesitate myself to make a statement about the effects of drawing oxygen through the "anoxic layer".
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I absolutely ABHORE the idea of drawing oxygenated water through the "Anoxic-zone" ( no oxygen ). In fact, if oxygenated water is drawn through the "no-oxygen" zone, then it isn't "Anoxic" anymore, is it? Sounds like a bad idea.

quote:
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And if you have some sand stirrers they will perform this job sufficiently.
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Good idea, I agree.

quote:
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Another thing to consider--in all of these proposed systems there is live rock being incorporated, am I correct? In that case, you really can't measure the actual effects of drawing water through the sand bed because in essence the LR is performing the same function. If the sytem works, is it because of or in spite of the plenum wasting? The only way to know for sure is to include no rock in the system at all.
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I don't think that is true. In my particular case, the plenum was installed about 5 mos. ago, but I have not drawn any water from it yet. My Nitrate has varied from as high as 80ppm down to 1ppm, but is now at about 5ppm. Phosphate has been as low as .5ppm, but is now at 1.5ppm. I have kept a rather steady ( and high ) bio-load for several months now.

If the "wasting" is able to improve Nitrate processing over a "standard plenum", then that effect will be observed over a period of time, by checking Nitrate in the "water column", after wasting begins, and continues.

Phosphate export is "almost guaranteed" to occur ( or be monitored )by way of it's presence in "the effluent".

Unlike ammonia which can ultimately be converted to gas which bubbles off, phospates can only be incorporated into the bacteria. Ultimately the DSB acts as a sink for phosphates, sulfur containing compounds and heavy metals. This is thought what acts to ultimately cause DSB's to crash. The sink gets full and starts to leak nutrients back into the water column.

Exactamundo!!!!!! . . . . unless the"sink" has a "drain"!

Ok, now a dumb question--if we know phosphates can be processed in a fuge with macro, and we know DSB works well on its own processing nitrogenous wastes, at least for a time, why bother with plenum wasting?

While I agree, that Phosphate will be "bound" in a refugium, for subsequent removal by harvesting and/or pruning, that does not stop phosphate from being processed in the substrate also.

The primary reason for plenum wasting, is to "avoid the crash". The secondary reason for plenum wasting is to achieve improved Nitrate processing.

>>
>>>>The reason for having substrate, is "FOR THE CRITTERS THAT REQUIRE IT!!! . . . . NOT for "processing ".
>>

I hope this is helpful, > barryhc

["Umm, fish?"]

Another thing to consider--in all of these proposed systems there is live rock being incorporated, am I correct? In that case, you really can't measure the actual effects of drawing water through the sand bed because in essence the LR is performing the same function. If the sytem works, is it because of or in spite of the plenum wasting? The only way to know for sure is to include no rock in the system at all.

I think that it's pretty unlikely that the stuff that gets deep into a deep sand bed will ever get out again. I can imagine some of it being pushed back out with the nitrogen bubbles, but not much. And I don't imagine that the bacteria do a lot of traveling between strata. So, unless there are some sand stirrers that are really pushing stuff around, I would think the live rock has a pretty minimal effect on processing anything that's managed to make its way all the way down to the manifold.

So, by testing the water you wind up pulling out from down there, you ought to have a pretty good idea of what frequent wasting is doing for you.

And as for me, the less frequent waster, I always expect the water will be disgusting....

[Obi-dad]

I still think having a drain with a DSB is way more complicated than having a drain with an SSB - and having the DSB external to the display (such as in fuge or even Calfo-style bucket), or even not having a DSB at all if you have sufficient live rock to do all the denitrification.

I am not bashing anyones' attempts to get a drain to work with DSB, just remarking that it gets very complicated trying to maintain the anaerobic layer, and worrying about how much, how often, whether you are hurting the anaerobes, etc. IMO, much easier to keep the DSB external (or not use one), and use the drain on the SSB to keep it from filling with gunk.

If you keep the DSB external, you don't have to worry about your display crashing, and can change the DSB out easily.

["Umm, fish?"]

Ok, now a dumb question--if we know phosphates can be processed in a fuge with macro, and we know DSB works well on its own processing nitrogenous wastes, at least for a time, why bother with plenum wasting?

A refugium can only bind the phos that gets to it. That is, the phos has to be in the water column. I will of course be running a 'fuge and will be trying other strategies to attempt to make sure that detrius stays in the water column as long as possible. But what we're trying to accomplish here is to figure out a way to get rid of the phos that gets stuck in the sand bed.

["Umm, fish?"]

If you keep the DSB external, you don't have to worry about your display crashing, and can change the DSB out easily.

This is true, but a lot of us would like to keep animals that need deep beds. And if you need a deep bed, it just makes sense to try to come up with a strategy that will try to keep the bed healthy for the long term.

We're really planning here for the post-4 to 5 year mark where it's said that some sand beds have trouble. I don't want that to happen to me. So I'm trying to plan for it....

[barryhc]

Originally posted by Obi-dad
I still think having a drain with a DSB is way more complicated than having a drain with an SSB - and having the DSB external to the display (such as in fuge or even Calfo-style bucket), or even not having a DSB at all if you have sufficient live rock to do all the denitrification.

I am not bashing anyones' attempts to get a drain to work with DSB, just remarking that it gets very complicated trying to maintain the anaerobic layer, and worrying about how much, how often, whether you are hurting the anaerobes, etc. IMO, much easier to keep the DSB external (or not use one), and use the drain on the SSB to keep it from filling with gunk.

Complicated "my foot"!!

"Fish", in as much as you insist on being a "lowly" infrequent flyer . . er . . . waster . . . er, well, whatever, You are obviously a man after my own heart.

Thanks, so much. > barryhc

["Umm, fish?"]

Complicated "my foot"!!

Yeah, I'd say the siphon is a pretty proven technology. At least, MY siphon is pretty proven. Sigh. I'm raising some FW fry and the daily 50% WC is wearing me out.

Thanks for the love. I'm in work hell and really procrastinating at the moment....

[barryhc]

Hell, I'm in "work heaven", are you looking for a career change?

> barryhc

["Umm, fish?"]

Hell, I'm in "work heaven", are you looking for a career change?

> barryhc

No, this too shall pass. If I'd hire more employees then I could take more time off. But, if I hire more employees, then I'd have to pay them (they are all so unreasonable that way).

Actually, my only employees are myself and my lovely bride. She's sick today, so I'm putting out her fires, too. Sigh....

We're just about to the end of our busy season, though.

[barryhc]

I have myself and my son ( just recently with my son ), "wife" handles "paper" mostly at night or on weekends. Had a bunch of "gorrilas" years ago, gave up for a while on gorillas, and just ran by myself. Were "firing up" again now with my son "on board", and were going to start with chimpanzees this time.

Gotta run. good night.

> barryhc

[reefclown]

Ok, now a dumb question--if we know phosphates can be processed in a fuge with macro, and we know DSB works well on its own processing nitrogenous wastes, at least for a time, why bother with plenum wasting?

Just for the sport of it

You can easily keep a system stocked with corals and few yards of fish using the proven methods, BB, DBS,e.tc. Now if the challenge was to continually up the fish stocking level to the capabilities of the system then some play is required.

The wasting plenum is just another idea to play with, sadistic maybe, but an idea to play with none the less

Just be kinda interesting to see what kinda mileage/flexibility it could provide in the handling of P and N.

I absolutely ABHORE the idea of drawing oxygenated water through the "Anoxic-zone" ( no oxygen ). In fact, if oxygenated water is drawn through the "no-oxygen" zone, then it isn't "Anoxic" anymore, is it? Sounds like a bad idea.

I'm having a chilled eve, so not going to start thinking


But for when the neurons kick in, are you planning to control/alter the depth of all 3 sediment zones or just the aerobic and anaerobic.
Why play with 2, when there are 3?

[barryhc]

Originally posted by reefclown
Just for the sport of it

You can easily keep a system stocked with corals and few yards of fish using the proven methods, BB, DBS,e.tc. Now if the challenge was to continually up the fish stocking level to the capabilities of the system then some play is required.

The wasting plenum is just another idea to play with, sadistic maybe, but an idea to play with none the less

Just be kinda interesting to see what kinda mileage/flexibility it could provide in the handling of P and N.

Very good ReefClown, I couldn't have said it better.

Of course, we don't want to forget the "nasties" that go "down the drain", instead of back up into the water column "eventually-maybe". ( The "forever-sand-bed"! )

But for when the neurons kick in, are you planning to control/alter the depth of all 3 sediment zones or just the aerobic and anaerobic.
Why play with 2, when there are 3?

Start on page 9, especially the post immediately prior to your first post, which discusses the three zones, and how they are "stretched".

Get those neurons "firing" again. > barryhc

[salty joe]

This is a good thread. I hope we can keep it going for years and years, because we're going to need to. Speaking of long threads, timewise that is, I wonder what the longest running thread that stayed active is on reef Central.? Thanks for all the interesting reading and links. I can hardly wait to see results from water that was drawn from the plenum. Thanks again.
Joe

["Umm, fish?"]

Hey barryhc! I wonder if I could ask your advice. I roughed out the manifold. I've just finished setting up my drill press. I'm ready to drill the siphon holes. What size holes do you think I should drill?

The tank is 4' x 2' - 4" or so in depth to make room for the overflows. The manifold is a basic rectangle, with crosses every 4.5" or so. That means I can only fit in a couple of holes per piece of pvc (in between the crosses). Thanks!

Andy