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Septic tank aeration

 
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Does anyone aerate their septic tanks? I have been trying to find information online and all I keep seeing are companies selling their latest gadget! I would imagine that there are benefits beyond the smell factor.
Does it produce better black water that can be filtered for other uses?
Does it break down the solids so tank doesn't need to be pumped as often? This one interests me on a couple levels. My solids side of my septic system is probably 3,000 to 5,000 gallons and I hate the thought of cleaning it but it will have to be done one day. The other thing is I am into aquaponics and aquaculture and in aquaponics some use mineralization tanks to break down the solids and they generally are aerated. I also suspect that with aeration there probably would be less nitrogen in the water to contaminate other water sources.
 
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As a septic system owner, I am interested in what people have to say. If there is a better method than a sucker truck every few years that discharges into municipal treatment, I'm interested.

But I have nowhere near the volumes you're talking about. This seems like an industrial/agricultural scale system.
 
Steven McKraken
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Douglas Alpenstock wrote:As a septic system owner, I am interested in what people have to say. If there is a better method than a sucker truck every few years that discharges into municipal treatment, I'm interested.

But I have nowhere near the volumes you're talking about. This seems like an industrial/agricultural scale system.



Actually I bought a school a few years ago and turned it into a fish farm. The septic tank was designed for hundred or so kids!
 
Douglas Alpenstock
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It takes a lot of aeration to break down unfavourable report cards. ;-)
 
Steven McKraken
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Douglas Alpenstock wrote:It takes a lot of aeration to break down unfavourable report cards. ;-)



Haha that is pretty good!
 
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These might help:










I did a search for "diy aeration septic system"

https://www.google.com/search?client=firefox-b-1-d&q=diy+aeration+septic+system

The first link looks promising: "inspectapedia"
 
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I mean, paper is carbon, so technically, they should actually speed up decomposition, shouldn't they?

Steve, I would look at the way that liquid cow feces is, in some places, processed to yield methane and a partially metabolised feedstock for further composting or process. A truly astounding quantity goes into a large, sealed tank, with internal infrastructure to swirl the contents. All materials in addition to the feces necessary for efficient methanogenesis are added, and it cooks in a methane-generating environment until a threshold is reached wherein there is no longer enough feedstock remaining to fuel the process.

So you get a natural gas you can cook with or perhaps even heat something with, and a feedstock for an aerated process to finish the composting. I like this idea because we get to use what otherwise would offgas into the atmosphere as fuel. Also, while it is possible to have a second-stage tank that would function identically to the methane bioreactor but with an oxygen-based process more like the brewing of actively aerated compost tea, which would be my preference, providing I can get the lab equipment to do regular testing, it is also possible to apply the solids directly to windrows of organic material to be composted, providing the process happens on healthy soil unlikely to be contaminated by errant, oxygen-starved pathogens.

How does this apply to you? That's a great question. You indicate that you have way more capacity than you presently require. I would try to quantify that, because if you're at capacity, you really don't have much time at all to experiment, whereas if you're even three-quarters-full on a system that is easily a hundred times greater than your personal need, you might have time to get the right biological conditions working for you in your septic tank and fields.

First-off, I wonder if anyone in your position has tried turning their over-large septic system into a methane generator. I mean, any large inverted container, a food-grade barrel with a bung near the bottom, could be floated in an IBU full of water as the seal. The bung could be tapped for gas, and the barrel would become buoyant as the volume of gas increased.

But as useful as this would be in the right situation, it seems rather like a stage added between plumbing and septic, wherein the solids are processed in a first-stage bioreactor as described above, and then drained to the septic tank.

If you're not familiar with compost extracts, and specifically actively aerated compost extracts, brushing up might be enlightening. Basically, I suggest you try operating your system almost exactly as intended, except that you brew and add actively aerated compost extract to the system regularly, atop the tank, and over the whole leaching field. To this, I would also add regular fungal slurry applications, probably something relatively hardy and aggressive like oyster mushroom.

Structurally, I think that if the tank and field were designed to vent, make sure those aren't obstructed. The problem I see with any other type of aeration is that your system already exists. Short of needing to replace it, where everything might be dug up, or at least a new one installed elsewhere, and you'd have unfettered access to install something like weeping tile inside your tank itself, whose ends you could extend up out of the ground, perhaps one extending into a black metal chimney, that would power a passive aeration of your tank as the hot air sought to escape, pulling fresh in from the other end of the weeping tile.

Adding appropriate biology would outcompete native and incoming pathogens, and adding oyster mushrooms, along with making sure there is enough carbon in and around the soil, will ensure that anything escaping the tank at any stage will be met with mycological resistance that will not only break them down, but redistribute things where they are needed.

I would love to hear from someone with more direct experience than I on the potential for mycology and actively aerated compost extracts to decrease volume inside a septic tank, but theoretically, if your capacity is high enough, you might be able to use a mycelial superhighway to keep your septic system clear.

And in the event that it doesn't address volume concerns, at least you'll know that what you're pumping out could go straight into your garden, or at least your woodlot and ornamentals.

But in any case, let us know how it goes, and good luck.

-CK
 
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Hi Steven:

My $0.02  ...I'd leave it be. My gut tells me there would be no advantage to aeration and could perhaps be detrimental to the system.

- as nitrogen is water soluable, it will leave the septic tank with the black water and be dispersed into the soil through the leaching field. The microbiome in the leaching field will then utilize and filter out the nitrogen.
- if adding air into a system, air will need to leave the system. The air leaving will be awfully smelly and may even contain pathogens.  A properly operating septic system should have no smell.
- when the tank is pumped, the solids are probably brought to a municipal waste treatment facility. These facilities often have aerators (hence the bad smell), the remaing sludge is probably incinerated.

I would not mess with the black water due to the possible presence of pathogens  ...let the system operate as it was designed.  If you are in an arid region, the waste water percolating into the soil may be beneficial to trees, but do not plant trees directly on top of or direcctly adjacent tor your leaching field. The roots will infiltrate the system and you will have problems ....that's assuming you have leaching trenches, leaching galleries may fair better, but I still would not risk it. If the leaach field is on a slope, you may consider planting trees downgradient from the system, they may possibly utilize the waster water and not interfere with the proper operatin of the system.

Assuming the system is relatively new, a system of that size was most likely designed by an engineer. You may be able to go to the local health and/or planning department and see if there are any plans on file showing the septic system design. This will give you a better idea with what you have to work with.


Hope this helps,
-Pete
 
Steven McKraken
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I will have to watch the videos. Funny how changing the search words get different results. That one article does bring a number of concerns with aerating a septic tank but I don't think that will be an issue for me. My septic system has a solids tank that is 3,000 -5,000 gallons and a "grey water"(what we usually call it around here) that is the black water side that is equal in size. The water gets pumped into the town sewer system and ends up in the town lagoon which has a couple cattails growing in it. And the water then percolates down to the water table.
For now I think I will aerate the solids side and see how things go. In the winter it is "aerated" as I put in 2-5,000 gallons a day of used fish water.
 
Steven McKraken
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I made a quick rough calculation, my septic tank might be closer to 8,000 gallons!
 
Steven McKraken
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Pete Podurgiel wrote:Hi Steven:

My $0.02  ...I'd leave it be. My gut tells me there would be no advantage to aeration and could perhaps be detrimental to the system.

- as nitrogen is water soluable, it will leave the septic tank with the black water and be dispersed into the soil through the leaching field. The microbiome in the leaching field will then utilize and filter out the nitrogen.
- if adding air into a system, air will need to leave the system. The air leaving will be awfully smelly and may even contain pathogens.  A properly operating septic system should have no smell.
- when the tank is pumped, the solids are probably brought to a municipal waste treatment facility. These facilities often have aerators (hence the bad smell), the remaing sludge is probably incinerated.

I would not mess with the black water due to the possible presence of pathogens  ...let the system operate as it was designed.  If you are in an arid region, the waste water percolating into the soil may be beneficial to trees, but do not plant trees directly on top of or direcctly adjacent tor your leaching field. The roots will infiltrate the system and you will have problems ....that's assuming you have leaching trenches, leaching galleries may fair better, but I still would not risk it. If the leaach field is on a slope, you may consider planting trees downgradient from the system, they may possibly utilize the waster water and not interfere with the proper operatin of the system.

Assuming the system is relatively new, a system of that size was most likely designed by an engineer. You may be able to go to the local health and/or planning department and see if there are any plans on file showing the septic system design. This will give you a better idea with what you have to work with.


Hope this helps,
-Pete



About the nitrogen, my whole town's black water gets pumped pumped to a small lagoon which doesn't hold much for water as we are in fairly sandy soils. I suspect that this lagoon might be part of the reason why there is high nitrates in our town's water. Our water table in the area ranges anywhere from 6' to 40' and in some places in a 40' span you hit 3 water seams.
My understanding of things is that the reason something like a septic tank is smelly is that it is anaerobic: basically the bacteria make H2S since there is no oxygen. When I start my fish season and start pushing a lot of water into the system it will stink for a couple days until it is aerated enough. Never mind the the fact when we have certain winds it creates a low pressure in the school, so it will smell things up at times. Or if we have the dryer going in that building we have to make sure the bathroom door is open as it will suck gasses out from septic tank. The bathrooms were built over top of the septic tanks, so minimal plumbing!  So I guess I could say aeration would be two-fold, if it breaksdown the solids faster and smaller an extend the period of pumping out the tank, that would be great and if it cut down the overall smell when we have these winds etc would be good.
I am not sure where the pumping guys take things to. Might be the neighing town's lagoon or dump it on a guys field.
I have an old sump mound but I am assuming it hasn't been used in probably 40 years. The whole septic system is about 60 years old.
For the filtration idea that I had in mind would be to use a wood chip bed and then a slow sand filter. Basically a wood chip bed the The Freshwater Institute designed and/or a bio bed that has been designed for spray chemical rinsate is what I had in mind if I decide to do something with it.
I hope that clears things up/makes a little more sense!
 
Steven McKraken
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Chris Kott wrote:I mean, paper is carbon, so technically, they should actually speed up decomposition, shouldn't they?

Steve, I would look at the way that liquid cow feces is, in some places, processed to yield methane and a partially metabolised feedstock for further composting or process. A truly astounding quantity goes into a large, sealed tank, with internal infrastructure to swirl the contents. All materials in addition to the feces necessary for efficient methanogenesis are added, and it cooks in a methane-generating environment until a threshold is reached wherein there is no longer enough feedstock remaining to fuel the process.

So you get a natural gas you can cook with or perhaps even heat something with, and a feedstock for an aerated process to finish the composting. I like this idea because we get to use what otherwise would offgas into the atmosphere as fuel. Also, while it is possible to have a second-stage tank that would function identically to the methane bioreactor but with an oxygen-based process more like the brewing of actively aerated compost tea, which would be my preference, providing I can get the lab equipment to do regular testing, it is also possible to apply the solids directly to windrows of organic material to be composted, providing the process happens on healthy soil unlikely to be contaminated by errant, oxygen-starved pathogens.

How does this apply to you? That's a great question. You indicate that you have way more capacity than you presently require. I would try to quantify that, because if you're at capacity, you really don't have much time at all to experiment, whereas if you're even three-quarters-full on a system that is easily a hundred times greater than your personal need, you might have time to get the right biological conditions working for you in your septic tank and fields.

First-off, I wonder if anyone in your position has tried turning their over-large septic system into a methane generator. I mean, any large inverted container, a food-grade barrel with a bung near the bottom, could be floated in an IBU full of water as the seal. The bung could be tapped for gas, and the barrel would become buoyant as the volume of gas increased.

But as useful as this would be in the right situation, it seems rather like a stage added between plumbing and septic, wherein the solids are processed in a first-stage bioreactor as described above, and then drained to the septic tank.

If you're not familiar with compost extracts, and specifically actively aerated compost extracts, brushing up might be enlightening. Basically, I suggest you try operating your system almost exactly as intended, except that you brew and add actively aerated compost extract to the system regularly, atop the tank, and over the whole leaching field. To this, I would also add regular fungal slurry applications, probably something relatively hardy and aggressive like oyster mushroom.

Structurally, I think that if the tank and field were designed to vent, make sure those aren't obstructed. The problem I see with any other type of aeration is that your system already exists. Short of needing to replace it, where everything might be dug up, or at least a new one installed elsewhere, and you'd have unfettered access to install something like weeping tile inside your tank itself, whose ends you could extend up out of the ground, perhaps one extending into a black metal chimney, that would power a passive aeration of your tank as the hot air sought to escape, pulling fresh in from the other end of the weeping tile.

Adding appropriate biology would outcompete native and incoming pathogens, and adding oyster mushrooms, along with making sure there is enough carbon in and around the soil, will ensure that anything escaping the tank at any stage will be met with mycological resistance that will not only break them down, but redistribute things where they are needed.

I would love to hear from someone with more direct experience than I on the potential for mycology and actively aerated compost extracts to decrease volume inside a septic tank, but theoretically, if your capacity is high enough, you might be able to use a mycelial superhighway to keep your septic system clear.

And in the event that it doesn't address volume concerns, at least you'll know that what you're pumping out could go straight into your garden, or at least your woodlot and ornamentals.

But in any case, let us know how it goes, and good luck.

-CK



Due to the fact the septic system in built out of concrete and part of the structure, I am limited in how much I can do. I can get aeration into  it by playing by the access hole. I know that after a week of putting fish effluent into the system things sure smell better so I think aeration will help. When I get doing it, it will probably end up in my youtube channel vlog.
Lol don't have a woodlot. Live in the prairies so whatever trees I have and will have are planted. Often have water restrictions during the summer as everyone is watering their gardens etc and our town's system can't handle it never mind I don't like watering with chlorinated water, and my well just doesn't produce enough water to handle my watering needs and I have big cisterns that catch rain water but I have to be careful how much of that I use as that is my water supply for my fish farm.
Unless I understand incorrectly, are not most pathogens anaerobic? So aerating should theoretically cut down on the number of pathogens there are. But I would say that I could be totally wrong.
 
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