Septic system failed - should I try installing an aeration unit?

Question

My septic system's leach field is not able to absorb the liquid that comes out of the septic tank any more. It flows out of the pipes in the leach field and surfaces in the grass. Based on the reading I have done (the "Septic System Owner's Manual" by Lloyd Kahn which is very good) there is a chance of recovering from this problem by installing an aeration system.

An aeration system pumps air into the septic tank, thereby encouraging the development of "aerobic bacteria". The aerobic bacteria need air to survive, and are more voracious eaters than the an-aerobic bacteria that are typically present in a septic tank without air pumped into it. The idea is that the aerobic bacteria will clean up the fluid in the septic tank and then they will also make their way into the lines of the leach field, clearing away the "bio-mat" that has formed over the years. This bio-mat is the thing that is clogging up the leach field, preventing it from doing its job.

Anyway, there are quite a few air pumping systems out there that are designed to be installed into an existing septic system. My question is, does anyone have experience with installing such a pump to deal with this type of problem, and if so how effective was it at clearing up the problem? Is it worth the investment? For some reason these systems seem to cost around $1,000, which seems a lot for what is basically just an electric air pump.

Update: I had the air pump system installed in April 2011, so let's see how it works..! It is an aero-stream unit which sits near my outside electric outlet and there's a plastic tube that is buried a few inches and that goes into the septic system via the outlet riser and down into the liquid. It pumps a lot of air in, the liquid churns around and bubbles continually. So far, I can say that the septic liquid is no longer foul-smelling. It has almost no odor any more. The level of liquid varies, depending on rainfall and water usage. Sometimes it comes to the top of the riser, at other times it's about 10 inches below the top. If this system works, I'm expecting that the level of liquid will fall gradually. This means that the lines are being cleared of gunk. Time will tell... I'll try to report back periodically.

Update June 30 2011 The level of liquid in my tank is about 18 inches below the top now. Very encouraging so far. Mind you, the Spring wet season is behind us, so it could just be due to the water table being lower in the summertime. Also my family was just out for a couple of weeks on vacation which took all the load off the septic.

Update Aug 20 2015 The aeration unit helped a lot but by itself wasn't enough. I ended up digging (by hand) a new "overflow trench" from the tank outlet. I used 3/4" gravel plus a piece of perforated plastic drainage pipe at the bottom. The trench was about 2 foot deep and 30 foot long and ended at a large flower bed which is slightly downhill from the septic tank. With the aeration unit plus this new overflow trench my septic tank is working well enough to not need replacement. The aeration unit ensures that the effluent that sometimes drains into the overflow trench is not foul smelling. This has been working for a few years now. Overflow will happen during periods of high usage such as lots of showering/dishwashing. It's not perfect but it's good enough.

Answer 1

I just had a breakthrough in my situation in the last couple of weeks. My leach field was about 95% clogged, very little if any movement. I had already diverted the graywater to another solution, which helped for awhile, but slowly the field failed to the point of essentially total failure. I have a single septic tank and wanted to try aerating it without the cost of a second tank. I learned a number of things that I haven't seen explicitly explained on any of the forums so I wanted to put it here to hopefully help someone.

I installed my aerator a few months back. Too much air volume and placing it in the center of the tank caused to much churning and cause solids to exit the tank. I did notice the smell though went from putrid to a smell like freshly turned soil (not coincidentally; the same aerobic bacteria live in airy soil). I spent a couple months thinking it didn't work. Water still not going out. But in the last couple of weeks I'm actually seeing the water levels fall to STAY at the edge of the outlet pipe!!!! First time ever!! I used the techniques below to avoid replacing my field without buying a $1000 solution.

You CAN aerate a single tank, but it's imperative that the aeration process doesn't agitate the incoming solids. They have to come into the first baffle and separate so the lighter material can rise and heavier solids fall. To accomplish this you have to use very fine bubbles and they have to be generated as far from the incoming line as possible, or they have to act inside an isolation vessel (there are videos where people use 12" pipe to contain the aerator). You can get diaphragm diffusers for as cheap as $35 if you search around, connected to PVC pipe, and use an air valve to supply JUST ENOUGH air pressure/volume to activate the diaphragm (air RELIEF valve, not cutoff. You'll damage your pump if you restrict airflow inappropriately). Too much and you get a rolling torrent (which you don't want). Place this diaphragm(s) near the output baffle or let it work IN the output baffle. This allows all the agitation to happen away from the settling part of the tank. THIS IS THE KEY, and is the reason why a separate aeration tank is ideal, so there's no chance of agitating the incoming. Also I had a 4" TEE on the outlet side which served as the separator. I put the two diaphragm diffusers on EITHER SIDE of the outlet TEE. You don't want bubbles going up INTO the TEE which could siphon some debris up in there. I got a septic filter brush and put down in the pipe to help filter the effluent, though as clear as the water is going out I don't think it was necessary.

One suggestion I received from a local contractor for my single concrete tank was to empty it, get inside and build a cinderblock wall giving 2/3 incoming/settling, and 1/3 aeration, but the tank has to be pretty good size to do that. You need several hundred gallons of aeration space. I put this on the burner as a next option, but turns out it wasn't necessary.

If you have a way of opening the other end of your leach lines to extend your field, at least temporarily, you get this freshly energized aerated bacteria through there quicker to let it go to work. My temporary relief is now closed off and the field appears to be working!!

Note I did NOT need to buy super duper amped up bacteria to add. From everything I've read this is hogwash and money makers for people. That's like buying weed seeds; give dirt some rain and you'll get the weeds. The bacteria will fill the space if they have oxygen.

My findings confirm for me that the low agitation solutions available out there for $500-$1000 would certainly work. I just chose to play around with a DIY solution.

Hope this helps someone.

Answer 2

Here are some ideas for reducing the load on your septic system:

Set your toilet reservoir to hold less water. Sometimes the float has an adjustment mechanism, or you can bend something. My 1950 toilet previously used 5 gallons per flush. I set it to the lowest fill level, and then put some mason jars in the reservoir to hold back more water. I don't put a lid on them, so the water will circulate and not stagnate.

Redirecting your greywater. Basically, greywater can be treated onsite with much simpler, cheaper systems than what is required for blackwater. Something as simple as redirecting your laundry greywater to a mulch pit can make a big difference.

See "Create an Oasis with Greywater" by Art Ludwig: http://www.oasisdesign.net/greywater/createanoasis/. He discusses which approaches are appropriate for which situations, and including a failing septic system.

You may also consider a waterless composting toilet. A simple system like the Lovable Loo works best, doesn't smell, is cheap to create and operate, and produces fantastic compost. And no plunging, ever. However, just as bacteria in poop is great for the compost pile, it's also great for the septic tank, so if you're still sending greywater in to the septic system, you may want to keep at least one flush toilet.

(Note that I don't actually have a septic system, so this comes from what I've read + my experiences with a sawdust toilet.)

Answer 3

I recently had my septic system pumped. While the guy was here working we got to chatting. He said he has worked on some sites where the leach field got backed up to the point that it was no longer working. His company installed a new leach field and switched the system over to the new field. Over the course of a couple years (!! yeah, this place he was working had some problems) the new leach field backed up. They decided to try and switch back to the old leach field, which they discovered had recovered over the course of a few years.

Not sure if it is possible/economical to do the same in your situation, but switching to a different system can give time for the old system to clear itself out. This is also possibly a last resort option.

Answer 4

I think typically an aeration system uses an entirely different tank design than a normal septic system, namely one that is separated into at least two chambers. I'm not sure that just adding an air pump will solve your problem.

Answer 5

In my area, these types of issues are not something the average homeowner can tackle. The county specifies the type of septic system that is required based on soil tests, drainage, and nearby bodies of water. The homeowner almost has no say. All work on systems must go though the health department, and all homes have to be inspected for a home sale. If the system is outdated and not up to code (no grandfathering), it needs to be updated / replaced. I am in NE Ohio.

So this may not apply for the original poster, but for others reading this question, be sure check your local government for required permits, regulations and inspections.

Answer 6

User 7403 was exactly correct. Adding an aerator to the septic tank simply stirs up the sludge and circulates it around the tank, sending it into your septic field to clog it up even more. The oxygenated water breaks the sludge up into tiny particles that even slips right through your Septic Effluent Filter creating a thick black sludge that enters your septic field, clogging it up further. If you place the aerator in the left chamber of your tank, all the sludge will end up in the right chamber. If you place the aerator in the right chamber, all the sludge in this chamber will end up in your leach field. User 7403 was exactly correct about reducing airflow to the bubbler to make fine, tiny bubbles. He was also correct about placing the bubbler into a pipe to prevent circulating sludge all around the tank.

I am using the Quad aerator Bubbler that I installed into the bottom of a 13 inch diameter pipe that rises above the water level so as not to disturb the scum layer. Holes near the bottom and holes below the top of this pipe allow water to recirculate vertically so as not to disturb the sludge layer. Water in the tank must remain motionless to allow sludge to settle on the bottom. I have reduced the airflow so that tiny bubbles come out of the aerator.

You clear up and rejuvenate your septic field by pouring Sodium Percarbonate mixed with water directly into your septic field. Add a pipe coming up vertically to your exit TEE so you can pour water into your septic field. 36 lbs of sodium percarbonate poured into your septic field over 4 days will remove all of the biomat, making your septic field just like new. ( Sodium Percarbonate is the chemical name for Oxyclean ). Google Oxyseptic for more details.

This works extremely well because it creates a LOT of free oxygen that destroys the biomat. Sodium Percarbonate mixed with water is the equivalent of 30% hydrogen peroxide. BEWARE !! HUGE BROWN BUBBLES will come boiling out of your septic field as the sodium percarbonate does its job eliminating the biomat.

For complete details and photos of how I rejuvenated my septic field, see this Google Documents link: http://tinyurl.com/Septic-Solutions

Answer 7

this is a common problem, first be sure to do as much research as you can. there's a lot of variables to consider. i have a single chamber cesspool, it's old, very old. i just built my own system. i put my air compressor down the basement, ran an air line with a quick release to the vent, I have no other access, attached a piece of garden hose to that and made sure it was long enough to get to the bottom of my cesspool. I then attached a four foot piece of soaker hose I had laying around to that. capping the end of course. and using stainless steel hose clamps. I have it set to maybe one psi., I had to go back and forth to look down the hole and adjust the regulator. it takes some time, but easy. you want to see some movement on the surface, some! not bubbling like boiling water on the stove. you will see a few bubbles from soap or what not. any oder should go away in one to two days, when the oder goes away, that means your now aerobically digesting. let me be clear, you DO want to mix and agitate the solids! it makes it easier for the bacteria to digest. they will eat all the black sludge! most likely it's your washing machine that's clogging your system. bath water is o.k. for your septic as the bacteria will eat hair and skin cells. they can't eat the synthetic fibers that come from you washing machines waste water. your have to get a filter for that and ideally run it somewhere else. I filter mine and run it out to a French drain, the bushes and grass love it! put a old nylon on the end of your washers waste pipe with a rubber band, do two or three loads of wash and you'll see what I'm talking about! keep in mind, your water level inside the tank will go up at first, and this is by no means a quick fix, I've had my system running for a year now and am finally seeing positive results. if your washer's going to your septic, run it somewhere else or start filtering it, then I would suggest having it pumped after aerating for a month to help get out all those fibers from the washer.

Answer 8

My solution is a three stage septic tank with a aeration pump and will never have problem with your septic on my system I have a baffle filter and on my pump in the tank I also have a pressure filter at the top of the riser the pump pumps to my septic field that is 250 feet from my house and the pump is a 3/4 horse so there are lot of ponys to pump it out to the field and I live Canada we have extreme weather here lots of snow and lots of rain my septic field is 52 by 52 round so it is a big field