DSB Heresy
- Thread starter ldrhawke
- Start date
BORECKI said:
Boris,
As ususal the knot head from Groton doesn't have the slightest idea of what he is talking about. If he's an engineer, he must drive a train. I wish he would butt out and stop giving people advice and acting like he designed the process and is now the expert. He doesn't even understand the process. 48 hours ago he was posting it won't work.
The last thing you want is an egg crate plemun, it will short circuit the flow and you will end up with large areas in the DSB unflushed. The plenum I described is purposely designed to cause a pressure drop so you get an even draw of fluid across the total bottom.
ldrhawke,
I understand that you are more concerned with conveying the basic concept of CPW, but automating anything with my tank is a big selling point for me, especially if it's not very expensive. Minimizing manual maintenance is one of the keys that first drew me to DSBs (live and learn) and now CPW. In fact it's a 3-for-1 deal. I'll be exporting waste, making gradual water changes, and enhancing the performance of my DSB (hopefully indefinitely) with one automated process.
As far as automating CPW without a PC, I just noticed that Drs F&S is selling a new Grasslin digital AC timer for $22 that has 6 on/off settings per day and battery backup. The description didn't say, but I'm assuming it has at least a 1 min programming resolution instead of the 1/2 hour you get with the mechanical timers.
Do you think using a pump instead of a siphon for waste removal has any merit? Wouldn't more pressure differential make for more even flow distribution?
Thanks for sharing your ideas.
Darrell
I understand that you are more concerned with conveying the basic concept of CPW, but automating anything with my tank is a big selling point for me, especially if it's not very expensive. Minimizing manual maintenance is one of the keys that first drew me to DSBs (live and learn) and now CPW. In fact it's a 3-for-1 deal. I'll be exporting waste, making gradual water changes, and enhancing the performance of my DSB (hopefully indefinitely) with one automated process.
As far as automating CPW without a PC, I just noticed that Drs F&S is selling a new Grasslin digital AC timer for $22 that has 6 on/off settings per day and battery backup. The description didn't say, but I'm assuming it has at least a 1 min programming resolution instead of the 1/2 hour you get with the mechanical timers.
Do you think using a pump instead of a siphon for waste removal has any merit? Wouldn't more pressure differential make for more even flow distribution?
Thanks for sharing your ideas.
Darrell
darrellh said:
I believe like you do... automate it. I just didn't want people scared off feeling it was complex and expensive.
A pump on the rise pipe would work great. Like...Maxijet 400 Powerhead. Then plumb its discharge to waste. That way you can pump it to a remote drain.
The timer idea is good, except the 1 minute is a pretty long time to discharge only a gallon and the flow rate would be very low. It would reduce the flushing action.
One way to get around it would be to discharge twice as much everyother day.
A lot of different ways to get nearly the same end result. Welcome to the CPW Society. :rollface:
Shoestring Reefer
New member
When did I post that it wouldn't work? Seriously, find one post that I made where I said it wouldn't work.ldrhawke said:
ldrhawke said:
I work as an engineer doing hydraulic analysis for power piping systems at a company that (among other things) developes thermo-hydraulic software for the numerical analysis of piping systems. Some of the software has nuclear pedegree, meaning it meets the requirements of 10 CFR 51.
Many of our clients are nuclear power plants. Analysis I have personally done includes prediction of plant performance under LOCA (Loss Of Cooling Accident) contitions, to determine if the plants aux feed systems can deliver the required flow under DBAs (Design Basis Accidents).
I have read Crane 410 from cover to cover; I am writing an internal document considering the Crane methodology of flow distribution in various "tee" configurations to Idelchick's (spelling) method, which is more tedious to do in longhand (luckily it's in the software) but more accurate.
I have helped develope software that does some of the things mentioned above, in addition to other areas of engineering.
Assuming the bed has equal flow resistance at all locations (ie., the same substrait used throughout, even plugging by detritus if that occures, etc.), the best way to have even flow across the bed is to have an equal pressure differential across the bed at all locations. The pressure at the surface of a bed in an aquarium will be constant; therefore, the best way I can see to have a uniform pressure differential is to ensure a uniform pressure in the bottom region.ldrhawke said:
I am not aware of any method that completely eliminates all channeling.
I believe a plenum would best accomplish this, rather than buried piping, because the plenum would establish a uniform pressure at the bottom of the bed. The holes in the pipe would draw water from the plenum, not the bed itself.
Also, pressure in the pipes will vary from location to location; that is the nature of flow, and the reason flow exists in the first place. The pressure gradient across the surface of a plenum would be more uniform because of the lower velocity at any one given point, compared to the differential experienced along the length of the pipe.
I'll state what I just said differently, to aid some people in understanding:
I believe that drawing water into a plenum instead of directly from the bed i would reduce channeling because of the two resons listed below:
1) The destination for the water as it exits the bed would be a plane pressure boundry, rather than several points
2) The pressure gradient of the planar pressure boundary will be more uniform than that of several point boundaries, each with it's own pressure.
Suggested Plenum Design: Boreki Method
The Boreki Method is a union of the DSB with Plenum design used successfully for approximatey 10 years by Aged Salt (Based on Dr. Rons method, but with an independently-developed maintenance methodology), and the experimental method of Idrhawke. It consists of a relatively coarse (compared to traditional DSBs) bed over a plenum. The plenum is comprised of a water-filled void separated from the bed by, for example, egg crate supporting a layer of finer mesh, or UG Filter.
The Boreki plenum contains two or more 1/2" pvc pipes, which are drilled along their length to allow water to enter the pipes. One suggestion for hole size and spacing is made by Idrhawke at the beginning of this thread. I recommend holes be placed near the bottom of the pipes rather than the top to place the holes further from the bed, reducing the contribution of localised low-pressure areas on channeling.
The pipes run the length of the tank and are connected at one end of the tank to a common riser, which exits the tank to a manually- or automatically-controlled drain system.
The egg-crate may be supported soley by the piping, or by additional supports if neccessary. The in-plenum drain piping should be spaced evenly, with the space between the piping and tank sides equal to 1/2 the space between pipes. In other words, for two drain pipes, place each pipe 1/4 of the tank width in from the side.
Please note, if you have a standard-sized tank for which an under gravel filter plate is available, that can be used in place of the piping, egg crate, and screen. Simply use the riser connections to remove plenum water from the system, rather than connecting them to a powerhead (which was their original design).
MarkS
Premium Member
Look man, I like your idea. I think it's great and has merit. However, your cocky, arrogent attitude is REALLY getting on my nerves. Take you fight with Shoestring to e-mail or private messages. He has yet to post anything even remotely looking like a flame towards you and has taken your attacks in stride. I can say, without a doubt, that he is the bigger man.
You don't like him and that's fine, but this thread is on the verge of being closed due to you and that really ticks me off!
You don't like him and that's fine, but this thread is on the verge of being closed due to you and that really ticks me off!
Algae Blenny
New member
MarkS is right. Shoestring Reefer has done nothing except be skeptical.
MarkS
Premium Member
I'm just posting from my past experiences posting ideas on these boards. I got constructive criticism on more than 90% of them and welcomed it. I really hate it when people post ideas or questions, but refuse to accept advice and/or answers that go against what they already have in mind. If you don't want to be criticized, then your wasting your time posting.
Not all criticism is bad. If you are too narrow minded to accept constructive criticism, then don't even waste my time posting.
Not all criticism is bad. If you are too narrow minded to accept constructive criticism, then don't even waste my time posting.
Scleractinian
Premium Member
ldrhawke said:
I'll try to avoid being added to the 'knot head' list... and I'd like to emphasize that I'm in no way questioning that your idea has validity (or that you have the right to name, trademark, or patent anything that you'd like)... Please TRY not to take an of the following as anything but an attempt on my part to ask for your thoughts or clarification... I'm a lowly public sector employee, and certainly not a CEO.
( <-- denotes good-natured sarcasm)Could you elaborate a bit on the hydraulic problems with using eggcrate over the grid, as suggested?
If you're trying to avoid short circuiting and channeling, it seems that drawing a small volume from a more discrete plenum space would actually help to accomplish this... What if you placed a sheet of acrylic, perf'd with uniformly distributed orifices and sealed to the tank sides, over the eggcrate...?
I deal with design challenges of maintaining uniform distribution in wastewater systems (various synthetic media and soils) under positive pressure at least daily... but keeping small orifices clear under negative pressure isn't something I've ever really thought about.
Might you also consider and comment on what may be the relationship of the function of your process to the mode of 'wasting'... What would you think of a continouos (non-pulsed, dropwise or via peristaltic pump) withdrawl of 'liquor' vs. your your present method? Are you hoping to move solids through the bed... at relatively very low velocities and only intermittently? Seems slower, uniform flows might make for best hydraulic uniformity, but would perhaps not be compatible w/ the chemistry desired...?
Also, have you considered testing your 'liquor' for PO4, Nx, etc? Might be interesting to relate what's coming out w/ your observed RedOx in another part of the system.
I just stumbled across this thread, and had been considering installing a small (2"x2") plenum connected to a 1/4" poly line to be sampled occasionally by withdrawl via a syringe (primarily 'cause I'm crazy and wanted to see what was going on in the sandbed) in a tank currently being assembled. I might just scale that plenum up a bit.
BTW, Though I've recently worked mostly with the other end of the system (the drinking water end), I'll have a chance to learn more next week about my first love: small scale sewage treatment ! (53rd Annual Michigan Onsite Wastewater Conference) I'd like to run some of the content of this thread by a few others who, like myself, and it appears, you, who are fascinated with what to do with lotsa poo...
Now we are getting down to the design nuts an bolts. I like that.
I will shortly be setting up a tank where stagnant areas in the sandbed will be a concern. I am planning a mangrove and seagrass tank and may have as much as 6" of sand to support the mangrove and the turtle grass (if this is the grass I use).
Further, I will need to intentionally put organics (in the form of soil) into the lower layers of the sand to provide the nutrients needed to support both the grass and the mangrove.
All this has me thingking that wasting might be a good idea for this tank.
Scleractinian
"Seems slower, uniform flows might make for best hydraulic uniformity"
This is what I would have thought, but I have no experience or training to back this up. Does grain size of the media effect how much it channels?
Is their any need to vary the hole size as you get further away from the drain in order to ensure more uniform draw across the entire plenum/bed. I would think that the preasure differntial would drop the further you got from the drain. Again, no training or experience to back that up, just too many brain cells with nothign better to do at 1:00am.
Fred.
I will shortly be setting up a tank where stagnant areas in the sandbed will be a concern. I am planning a mangrove and seagrass tank and may have as much as 6" of sand to support the mangrove and the turtle grass (if this is the grass I use).
Further, I will need to intentionally put organics (in the form of soil) into the lower layers of the sand to provide the nutrients needed to support both the grass and the mangrove.
All this has me thingking that wasting might be a good idea for this tank.
Scleractinian
"Seems slower, uniform flows might make for best hydraulic uniformity"
This is what I would have thought, but I have no experience or training to back this up. Does grain size of the media effect how much it channels?
Is their any need to vary the hole size as you get further away from the drain in order to ensure more uniform draw across the entire plenum/bed. I would think that the preasure differntial would drop the further you got from the drain. Again, no training or experience to back that up, just too many brain cells with nothign better to do at 1:00am.
Fred.
Scleractinian,
I agree with ldrhawke on not wanting to use eggcrate. With ldrhawke's method, all of the pressure drop caused by siphoning is evenly distributed across the 1/32" holes (provided there is enough gridding to avoid pressure drops in pvc sections that are far away from the siphon connection). The reason the pressure drop occurs at the holes is that the area of all of the holes combined is small compared to the effective cross-sectional area of the pvc grid, which is why ldrhawke recommended using as much gridding as possible. Since each hole is the same size, the flow near each of these holes will be evenly distributed.
If you now put an eggrate on top of the pvc grid, then you have just created a new large cross-sectional path between the pvc holes and the substrate that will allow the flow from the substrate to take the path of least resistance. At first the flow may be fairly even thru the substrate, but as some areas become more clogged than others, the flow rate thru these areas will decrease. Then it becomes a vicious cycle where the areas with low flow become even more clogged.
For MarkS and others, please cut ldrhawke some slack. Arrogant or not, his ideas may have a big upside for the rest of us. Besides it seems to me that Shoestring developed the attitude first. I just wish ldrhawke had kept him on his "ignore list" like he said he was.
Darrell
I agree with ldrhawke on not wanting to use eggcrate. With ldrhawke's method, all of the pressure drop caused by siphoning is evenly distributed across the 1/32" holes (provided there is enough gridding to avoid pressure drops in pvc sections that are far away from the siphon connection). The reason the pressure drop occurs at the holes is that the area of all of the holes combined is small compared to the effective cross-sectional area of the pvc grid, which is why ldrhawke recommended using as much gridding as possible. Since each hole is the same size, the flow near each of these holes will be evenly distributed.
If you now put an eggrate on top of the pvc grid, then you have just created a new large cross-sectional path between the pvc holes and the substrate that will allow the flow from the substrate to take the path of least resistance. At first the flow may be fairly even thru the substrate, but as some areas become more clogged than others, the flow rate thru these areas will decrease. Then it becomes a vicious cycle where the areas with low flow become even more clogged.
For MarkS and others, please cut ldrhawke some slack. Arrogant or not, his ideas may have a big upside for the rest of us. Besides it seems to me that Shoestring developed the attitude first. I just wish ldrhawke had kept him on his "ignore list" like he said he was.
Darrell
I'm new here but I'd just like to pipe in (pun, hah!) with a comment on the grid vs. tube idea. I've been reading this thread with amazing concentration tonight.. lots of interesting ideas.
To me I see the reason why uniform flow would exist with tubes vs. the grid for the following reason:
The 1/32" holes all combined under tight granule sand will likely flow less than the uplift siphon draws. This is the pressure drop, and why a steady even draw would probably be made. For example, ever -try- siphoning a tank _empty_ that had sand in it? You can have a puddle of water and no water with sand separating it. It just doesn't flow through the sand easily. It resists flow.
A good analogy would be having one pipe near the uplift tube that has a theoretical 6" round hole drilled in it (I know, ridiculous but work with me here) with screen over it, and that's it. Draw water from it, and that's probably the only area through the sand water will pass. The grid has an area even bigger than 6".. but wherever the draw tube attaches to it, I doubt water will come from more than a 6" diameter area around it.
Some food for thought on all this though. I'm setting up a new 90 gal reef with 200# of Southdown right now on this very night (or now 2:28AM morning, argh time flys) ... 1 pint of water went a long way to saturating that much sand. I can't say it holds more than a couple of gallons before rising above the sand while filling. So if I were to siphon off a pint, it isn't 1:720 of the total water. It's more like 1/10th of the water saturating the sand. That could be a lot. As in, enough to largly impact the anarobic activity going on by drawing the oxic area down significantly.
ldrhawke, you noted a large decrease in the odor of the murk in short order after starting this... maybe things have become more aerobic. This isn't necessarily bad, but it might not be good either depending on what folks are relying on their DSB to do.
It's stuff like this that makes me want to see this used by different people for a couple of years and compare it to their own results without it before using it myself.
Now, don't get me wrong-- I'm burying 1/2" PVC tomorrow. ... it just may be a year or two before I turn that valve. Maybe I'll turn it when I start thinking my DSB needs a flush ...
To me I see the reason why uniform flow would exist with tubes vs. the grid for the following reason:
The 1/32" holes all combined under tight granule sand will likely flow less than the uplift siphon draws. This is the pressure drop, and why a steady even draw would probably be made. For example, ever -try- siphoning a tank _empty_ that had sand in it? You can have a puddle of water and no water with sand separating it. It just doesn't flow through the sand easily. It resists flow.
A good analogy would be having one pipe near the uplift tube that has a theoretical 6" round hole drilled in it (I know, ridiculous but work with me here) with screen over it, and that's it. Draw water from it, and that's probably the only area through the sand water will pass. The grid has an area even bigger than 6".. but wherever the draw tube attaches to it, I doubt water will come from more than a 6" diameter area around it.
Some food for thought on all this though. I'm setting up a new 90 gal reef with 200# of Southdown right now on this very night (or now 2:28AM morning, argh time flys) ... 1 pint of water went a long way to saturating that much sand. I can't say it holds more than a couple of gallons before rising above the sand while filling. So if I were to siphon off a pint, it isn't 1:720 of the total water. It's more like 1/10th of the water saturating the sand. That could be a lot. As in, enough to largly impact the anarobic activity going on by drawing the oxic area down significantly.
ldrhawke, you noted a large decrease in the odor of the murk in short order after starting this... maybe things have become more aerobic. This isn't necessarily bad, but it might not be good either depending on what folks are relying on their DSB to do.
It's stuff like this that makes me want to see this used by different people for a couple of years and compare it to their own results without it before using it myself.
Now, don't get me wrong-- I'm burying 1/2" PVC tomorrow.
... it just may be a year or two before I turn that valve. Maybe I'll turn it when I start thinking my DSB needs a flush ... keman,
Since your right in the middle of adding water to a new DSB, I just wanted to make sure that you were adding saltwater and not fresh. A while back, there was a Dr. Ron thread that said a freshwater saturated DSB could take weeks to equalize salinity throughout the DSB to the point where it could begin cycling.
Darrell
Since your right in the middle of adding water to a new DSB, I just wanted to make sure that you were adding saltwater and not fresh. A while back, there was a Dr. Ron thread that said a freshwater saturated DSB could take weeks to equalize salinity throughout the DSB to the point where it could begin cycling.
Darrell
Hmm... (bleary sleep depriven gaze)
Uh..
Yeah. Looks like I'll be stirring that sand up quite a bit tomorrow when I add that PVC... and salt.
Thanks for the reminder... yeah, salt was going to be added tomorrow. This tank hasn't held water since it was moved and I figured I'd reduce the damage potential by letting fresh water sit in it overnight. I didn't want to add the sand to the water and then deal with a thick layer of thin sediment settling on top.. but it looks like that'll be the case regardless.
I had a marine tank split open and dump 80 gallons of salt water onto the floor once. Bottom seam let go. 2nd floor. New tank, did it overnight. $8000 damage to the house. Saltwater ran down the furnace ducting and even ruined the furnace motor...
Uh..
Yeah. Looks like I'll be stirring that sand up quite a bit tomorrow when I add that PVC... and salt.
Thanks for the reminder... yeah, salt was going to be added tomorrow. This tank hasn't held water since it was moved and I figured I'd reduce the damage potential by letting fresh water sit in it overnight. I didn't want to add the sand to the water and then deal with a thick layer of thin sediment settling on top.. but it looks like that'll be the case regardless.
I had a marine tank split open and dump 80 gallons of salt water onto the floor once. Bottom seam let go. 2nd floor. New tank, did it overnight. $8000 damage to the house. Saltwater ran down the furnace ducting and even ruined the furnace motor...
Thanks Mark S,
Well said, and my thoughts exactly! Ldrhawke is obviously very offended at the slight criticism and skepticism, and has resorted to flaming personal attacks.
Ldrhawke, I must say this attitude and lashing out seriously detracts from my interest in what could be a GREAT thread. Why not gracefully answer everyones questions and skepticism and leave out the flames.
This is what RC is about, sharing ideas and thoughts. Thank you for sharing your technique, but know that with this many people reading this forum there are bound to be a ton of questions and a healthy dose of skepticism in EVERYTHING from salinity levels to bubble size.
Onward!!
Chris
Well said, and my thoughts exactly! Ldrhawke is obviously very offended at the slight criticism and skepticism, and has resorted to flaming personal attacks.
Ldrhawke, I must say this attitude and lashing out seriously detracts from my interest in what could be a GREAT thread. Why not gracefully answer everyones questions and skepticism and leave out the flames.
This is what RC is about, sharing ideas and thoughts. Thank you for sharing your technique, but know that with this many people reading this forum there are bound to be a ton of questions and a healthy dose of skepticism in EVERYTHING from salinity levels to bubble size.
Onward!!
Chris
Shoestring Reefer
New member
What you are saying makes sense untill you consider that, with the buried pipe idea, flow will not necessarily enter all holes equally, especially if the substrait gets clogged.darrellh said:
In other words, if the substrait gets clogged, I don't believe any method will provide uniform flow.
Shoestring Reefer
New member
Yes, with the pressure differential would drop as you get further from the drain-hense the plenum idea.Fredfish said:
Bigger holes as you got further away would help; the problem is knowing how big to make the holes. The pressure differential will change as flow rate changes, so progressively larger holes best-suited for one flow rate (in terms of flow distribution) would not necessarily be best-suited for a higher or lower flow rate. I guess it would work if you vary the duration of draining, rather than flow rate.
If you decide to go that rout, pm me and I'll set you up with some formulas, if you're interested; ldrhawke may also be able to help, because that's sort of what his company does (but with air).
Shoestring Reefer
New member
Um, "infallabilty"? Are you not aware that during the Three-Mile incident, PART OF THE CORE MELTED INSIDE THE CONTAINMENT VESSEL? Thats right, I've seen diagrams of where internals started, and where they ended up.ldrhawke said:
Seriously, it's nice to let yourself sleep at night, especially if you're downwind from a plant, but the system is NOT infallable.
If you would like to discuss anything specific, let me know.ldrhawke said:
