Bog/upflow wetlands filter experience

[addy1]

I have a feeling addy that you're really benefitting from having such a large area. And Meyer mentioned you have your feed from the pond going through a series of smaller tubs? I imagine this helps settle some of the detritus? I'm contemplating how I might put some sort of mechanical filter ahead of the bog but it might just be I should put more effort into being able to backflush easier, for future issues. Doing something every year might also help, as opposed to waiting until it gets bad.

Michael

The smaller ponds are fed by a loop going from the big pond into the small ponds, back into the big pond. The water does not enter the bog from this area at all. There is no filtering except what the plants in the small ponds do.

They are at the opposite end of the pond from the pumps intake.

 

[Meyer Jordan]

The water does not enter the bog from this area at all

If you think about it @addy1, indirectly it does as the water that travels through the stream and consequently the pools reenters the pond mechanically filtered.

 

[brokensword]

Meyer; wouldn't that mean that the addy's bog is not 'prefiltered'? The small ponds are doing some mechanical treatment and therefore slowing the 'clogging' process, though, right? I was thinking I might do something like this as I can probably set up a new stream with plants that would flow into the bog or pond easier than anything like a skippy. Still, can this process (small pond mech filtering flow-back) be quantified?

And, in your experience, have you found the stack-cleanout method of backflushing/cleaning an upflow wetlands to be effective? Addy didn't get much, though I did, even if I had to hose down almost every rock in the bog and put it back. Do you have any 'stories' or links I could read or watch? In googling, I didn't find much about actual real bog backflushing, which makes me think hardly anyone does it or no one's put their experience in easy public reach.

Addendum; Meyer, I had an idea I'd like to run by you. If I took the flow from the sub pump beyond the waterfall tee and instead of 'forcing' the water up through the bog, let it flow into a stream with plants, then have it exit passively into the 12" bog stack, do you think the bog would still work? That is, do I need the pressure from the pump to make the upflow work? If I let the stream filtered water flow like a water fall into the stack and it eventually began overflowing higher than the bog, I'd know there was blockage in the bog. That said, I fear it would happen too easily.

The second idea would be then to have a pump take the 'stream filtered' water and force this then into the existing bog inlet, but that probably means I might starve this new pump if the stream filter doesn't let enough water past. What are your thoughts?

Michael

 

[Lisak1]

btw, LisaK1, my layers stayed pretty well intact; there was some pea gravel down low but not much!

If we had left it alone, that would have been true. The problem we had was we had to constantly rake and shift the gravel around in our downflow bog to clear off the collected debris and try to clean it out to keep it from clogging up. Eventually the mixing of the pea gravel with the construction gravel created the perfect situation to decrease the drainage rather than increase it. Plus we ended up with a lot of the not so attractive gravel at the top rather than being covered by the preferred pea gravel. Live and learn!

Now we have all one size cobble which is smooth and easy to clean. We pull out the larger debris by hand (two seconds work) and then hose it down (another 30 seconds) and it's all good!

 

[addy1]

If you think about it @addy1, indirectly it does as the water that travels through the stream and consequently the pools reenters the pond mechanically filtered.

It does get some filtration, the feed to the small ponds is a 3/4 inch garden hose T'd off the flow into the bog. The plants love the dirty water they grow great.

The stream does the same, but it only runs around 4-5 hours a day. I have it turn on 3 times a day. Keeps the mosquitoes away, keeps the stream and deck ponds fresh.
1000 gph fresh water pump that pushes it up 100 feet plus/minus of head pressure.

 

[brokensword]

The idea of incorporating 'bogs' into the filtration process in a pond was derived from the enormous constructed wetlands that are used for the cleansing of municipal and industrial waste water. Somehow over time in the adoption process several important aspects of constructed wetlands have
been omitted and/or neglected.
First, although a 'bog' may be used for nitrification, the original (and still) main purpose of constructed wetlands is to 'polish' (removal of Nitrate, heavy metals, and other organic and inorganicpollutants) the water through the use of phytofiltration.
Because of the immense surface area available on the gravel used in construction, nitrification will also occur.
In either usage the bog should be treated as at least secondary filtration. Mechanical filtration should definitely precede a 'bog' much as mechanical filtration should precede the use of any biofilter. Efficient removal of suspended solids beforehand is paramount for ensuring the efficiency of any biofiltration.
This mechanical filtration can be in the form of a skimmer, RDF (Rotary Drum Filter), settling tank/chamber (@addy1 's multiple smaller ponds are an example) or other means.
Without this pre-filtering (Mechanical), a 'bog' will clog. Some may take longer to do so than others.
Overgrowth of 'bog' plants can also cause issues as the roots grow and trap minute suspended particles resulting in clogging and water channeling.
A 'bog' should not be over-planted or allowed to become overgrown. Thinning should be done on an as needed basis, but no less than once per year.
If a 'bog' has become clogged from accumulation of organic particulate then two options are available: backflushing or deconstruction. The former is usually the first choice. Since a 'bog' operates utilizing an upflow of water then backflushing should be accomplished with downflow in order to dislodge any particulates causing the clogging.

@Meyer Jordan

Could you comment on if the following idea will work prior to me actually doing it? I thought to route the sub pump feed into a 55 gallon drum to feed the bottom, it'll rise through a bio mass then have to go through some sort of Matala like pad before being forced out a top outlet which I'll feed back to the original bog inlet. I say 'forced' because I plan on having an 'open top' barrel that can be sealed. Am I right in assuming that the pump will force the water through this new mech filter?

Thanks for the help.

Michael

 

[Meyer Jordan]

Meyer;

Could you comment on if the following idea will work prior to me actually doing it? I thought to route the sub pump feed into a 55 gallon drum to feed the bottom, it'll rise through a bio mass then have to go through some sort of Matala like pad before being forced out a top outlet which I'll feed back to the original bog inlet. I say 'forced' because I plan on having an 'open top' barrel that can be sealed. Am I right in assuming that the pump will force the water through this new mech filter?

Thanks for the help.

Michael

Will this be an air-tight seal? And, if so, what provisions will there exist for cleaning this unit? What size (gph) is the pump?

 

[brokensword]

Will this be an air-tight seal? And, if so, what provisions will there exist for cleaning this unit? What size (gph) is the pump?

@Meyer Jordan
Yes, since the top is sealable but open-able, I'll service the mats this way.

Something line this;

http://www.bayteccontainers.com/oppldr55gal.html#gsc.tab=0

The pump is about 4000 g/h.

 

[Meyer Jordan]

This will work but the outlet at the top will need to be 3" diameter. Even sealed I doubt if the lids of these drums are designed to maintain any integrity under pressure, so, in essence, although you are actively pumping into the drum the discharge without pressure will for all practical purposes be gravity flow. Consequently a 3" discharge pipe is needed to handle 4000 gph.
On a side note, typically in an upflow filter, the filter pads are on the bottom of the filter with the biomedia above.

 

[brokensword]

This will work but the outlet at the top will need to be 3" diameter. Even sealed I doubt if the lids of these drums are designed to maintain any integrity under pressure, so, in essence, although you are actively pumping into the drum the discharge without pressure will for all practical purposes be gravity flow. Consequently a 3" discharge pipe is needed to handle 4000 gph.
On a side note, typically in an upflow filter, the filter pads are on the bottom of the filter with the biomedia above.

@Meyer Jordan is there a way to keep the pump's pressure up? That was my intention. I would plan on getting/making a gasket to fully seal the drum if needed. And I was putting bio material beneath the mats only because I have the space, not because I need bio filtering (that's what the bog is doing, right?). The lower portion can become a settling tank which means I'll also have a drain, now that I can/will locate this drum above ground.

I figured to try and keep a force into the bog as I have it now but wanted to incorp the mech filtration you suggested. Can you modify what I'm proposing to make it work as I wish? I also figure IF the bog gets backfilled again, there's still the tee for the falls to alleviate any back pressure on either the bog or new drum filter. Also, I put the mats on top simply to make cleaning easier. I could fill it up with only mats but I figure only the first couple would need cleaning and the rest up above would act more like that bio substrate. I'm trying to make this low maintenance.

And I don't want a gravity fed bog because I don't think the water will push up as easily as it does now, thus reducing its efficacy. That's important, yes? If not, can you explain why? Another question would be; is there a way to test if the drum would hold under X pressure? I actually have a pair of these in my basement for water (cut tops off long ago so can't use them, I don't think, unless I can get a lid that locks) and they are VERY heavy duty.

Thanks again for helping.

Michael

 

[Meyer Jordan]

I did not realize that you are intending to use this drum as a mechanical filter. Invariably, the pump is placed after the mechanical filtration in the flow of water not before.
I don't believe in my 20 something years involved in aquatic systems that I have ever heard of, much less seen, a pressurized mechanical filter. Placing the mechanical filtration on the outflow side of the pump only makes the filtration process more difficult.
I would recommend that you utilize this drum as a gravity feed settlement tank and plumb it accordingly. This would require that this module be placed in an excavated pit to function.

 

[brokensword]

Meyer; the reason I'm doing this is to save the bog to do what it does best. I don't have any room nor desire to dig and bury this tank. I'm attaching a video of someone who did what I'm thinking of doing. Now, he's an amateur and I don't know how long everything worked, but he seemed to do exactly what I want. He does have an external pump and the flow to his filter is gravity fed, but I've heard you say sub pumps are for pushing water, not pulling, which is what I want to do. The way I see it is the filter pads in the new drum will retard the flow to the bog but the pump won't burn out as it has a safety valve in being teed at the water fall before it ever gets to the bog/new filter. What, other than this, would be the downside to doing what I'm thinking? The ease of changing the pads is paramount here along with having room for such a mech filter. Putting a filter prior to the sub pump isn't going to happen so I'm just trying to find a way to both send the pond water to a mech filter and then to still have some pressure to force the water down and up through the bog. From the video, that seems to be what has been done and with my setup, the pump will never be starved for water (like maybe it might in the vid) nor will it clog forward without a safety.

Since I already have a screen on the pump inlet, what will be going to the mech filter will just be all the crud I just got done washing out of the bog gravel, i.e. very small particles.

Anyway, can you take a peek at the vid and comment further? I'm willing to give this a try but only if I can have some sort of pressure out of the filter and back into the bottom of the bog, even if it's reduced.

link;

Michael

 

[Meyer Jordan]

Meyer; the reason I'm doing this is to save the bog to do what it does best. I don't have any room nor desire to dig and bury this tank. I'm attaching a video of someone who did what I'm thinking of doing. Now, he's an amateur and I don't know how long everything worked, but he seemed to do exactly what I want. He does have an external pump and the flow to his filter is gravity fed, but I've heard you say sub pumps are for pushing water, not pulling, which is what I want to do. The way I see it is the filter pads in the new drum will retard the flow to the bog but the pump won't burn out as it has a safety valve in being teed at the water fall before it ever gets to the bog/new filter. What, other than this, would be the downside to doing what I'm thinking? The ease of changing the pads is paramount here along with having room for such a mech filter. Putting a filter prior to the sub pump isn't going to happen so I'm just trying to find a way to both send the pond water to a mech filter and then to still have some pressure to force the water down and up through the bog. From the video, that seems to be what has been done and with my setup, the pump will never be starved for water (like maybe it might in the vid) nor will it clog forward without a safety.

Since I already have a screen on the pump inlet, what will be going to the mech filter will just be all the crud I just got done washing out of the bog gravel, i.e. very small particles.

Anyway, can you take a peek at the vid and comment further? I'm willing to give this a try but only if I can have some sort of pressure out of the filter and back into the bottom of the bog, even if it's reduced.

link;

Michael

Quick observations:

-This is a biofilter. It bears little resemblance to any mechanical filter.
-Using this as a mechanical filter will be a maintenance nightmare especially when fed by a 4000 gph pump, unless you can devise a way to backflush this module( a feature that the DIY filter in the video did not have). Also I would guess that the pump feeding the filter in the video does not exceed 1500 gph. Which is one reason that the module does not leak.

I realize that available space is nearly non-existent but I can't see you creating a new problem in trying to correct an existing problem.

 

[brokensword]

@Meyer Jordan ; thanks for continuing to help! And I'm appreciative of the fact you don't want me to induce new problems––that's what I want too. I did intend to have a drain at the bottom for backflushing. I had intended to have the top removable so I can easily access the pads so I can clean them. The 4000 sub pump is used for BOTH waterfall and bog, so I think I'm not getting the full 4000 aimed squarely at this new filter. Plus, I'm sure I'm losing pressure as it must rise from about 2' below the pond surface to 3' at the waterfall top, then down again until it'll rise 3' again to fill this proposed filter. I have the sub pump feed teed at the waterfall with a valve, as well as a valve on the bog feed. So I have ways to throttle at will.

Now, I'm thinking I might have the terms mixed up; I'm trying to filter out the small particles that accumulated between the pea gravel and that which settled out in the larger cobbles of the bog. Won't layers of various types of Matala filter material do that for me, thus saving the bog from getting those? I can then rinse them clean and put it all back at various time intervals. That's what I'm trying to achieve, whether it be bio or mech in terminology. If you have a better way so I can establish this, let me know. I'm hurting for space simply because I have only about 30" (planted) surrounding my pond/stream/bog to work with. My pond is enclosed and I have a patio attached. I'll include an aerial+pano to show you what I'm working with. I had thought to put this new filter either on the patio right next to the bog or to actually place it on top of the bog clean out stack, which will help if there are any leaks.

Is this undoable without making it laborious to maintain? Will there be enough pressure re-entering the bog so I get a good upflow? This last is my main concern.

I'm also going to attach my conceptualization diagram.

this is an old picture, but the pump is lower rt and thte waterfall lower left with the bog upper left.

pano; bog is rt, waterfall middle, sub pump left with the hose wrapping around beneath the soil, working its way to the top of the falls where it's teed, then back down to the bog inlet.

 

[Meyer Jordan]

I'm sure I'm losing pressure as it must rise from about 2' below the pond surface to 3' at the waterfall top,

Head is measured from water surface to highest elevation, so you really only have 3 feet of head. The base flow ratings given for most pumps is for 5 feet of head, so other than friction loss, you should not be losing that much flow.
What you are thinking of doing is workable IF the modified drum filter will handle the pressure generated by your pump.
I guess what I am saying is that by pressurizing this module you are only adding to the total time that you will devote to maintenance (cleaning/backflushing).
Have you considered the idea of retrofitting a skimmer?