The septic system biomat: this article explains the formation of the biomat below septic drainfield trenches and around cesspools and some drywells and explains what the biomat does.

The biomat, a bacterial slime layer in the soil below the leachfield and around other wastewater disposal systems, is a critical component of private septic systems - it is responsible for treatment and reduction of biological solids and pathogens in septic wastewater effluent which is discharged into the soil from a septic tank.

The most common and most expensive failure of private systems occurs as soil clogging and failure of the absorption system to continue to accept water.

What is a septic biomat? - what is the septic drainfield "biomat" layer?

Here we'll describe how the biomat forms, how the soil eventually becomes clogged by a too-thick and too-extensive biomat, and how you can extend the life of the soil absorption system by protecting the formation of the biomat.

The origin of this text is the Winter 2005 issue of Pipeline, a publication of the National Environmental Services Center, used, adapted, and expanded with permission. [Edits and additions to the text are by the website author.]

Article Contents:

• BIOMAT FORMATION & SEPTIC LIFE
  • WHAT's A SEPTIC SYTEM "BIOMAT"
  • HOW THE BIOMAT FORMS
  • BIOMAT CONSTITUENTS
  • BIOMAT FORMATION PATTERN IN SOIL
  • DRAINFIELD CLOGGING PROCESS
  • EXTENDING DRAINFIELD LIFE

The biomat is a bacteria layer which forms in soil below and around drainfield trenches where septic effluent or wastewater is discharged.

This layer is critical in the processing of fine biological solids and pathogens which are in the effluent, and without it the septic system would not be adequately treating the effluent. Inadequately-treated effluent released into the ground risks contamination of nearby ponds, wells, streams, etc. A similar layer also forms around drywells used to accept graywater from buildings.

Septic effluent, (or onsite wastewater), is discharged into a soil absorption system (or drainfield, seepage pit, or cesspool) from the septic tank which should, if it's working properly, have retained all large solids.

The job of the soil absorption system, or "SAS", is to further treat the effluent to reduce the level of biological solids and pathogens to a level acceptable for further movement of the liquid into remaining soils. Inadequate treatment of effluent would mean that sewage and pathogens would be discharged into and contaminate nearby ground water.

How the biomat forms: how does the Biomat Form in a septic system effluent absorption system?

As the effluent is discharged into the SAS, bacterial growth develops beneath the distribution lines where they meet the gravel or soil. This layer is known as the clogging mat, clogging zone, biocrust, and bioformat.

It's also referred to by some as the "slime layer" and it's easily visible as a usually-gray slimy layer in the soil displayed if one excavates a cross-section of an absorption system trench.

This biomat (biological mat) is a black, jelly-like layer that forms along the bottom and sidewalls of the drainfield trench. This clogging zone [eventually] reduces infiltration of wastewater into the [surrounding] soils.

Septic biomat constituents: what is the biomat made from?

The biomat is composed of anaerobic microorganisms (and their by-products) that anchor themselves to soil and rock particles.

"Anaerobic" refers to microorganisms which do not require high levels of oxygen, as opposed to "aerobic" organisms which do. Septic waste and wastewater treatment involves both aerobic and anaerobic organisms. "Aerobic" bacteria require oxygen. In either case but digesting different pathogens, the bacteria's food is the organic matter in the septic tank effluent.

Less than one centimeter to several centimeters thick, the biomat acts as the actual site for effluent treatment.

Septic biomat formation patterns in soil trenches: the Biomat formation pattern in leach field trenches

The biomat forms first along the trench bottom near the perforations [in the drainfield piping which delivered the effluent along the trench] where the effluent is discharged, and then up along the trench walls.

[As the bottom becomes clogged effluent rises in the trench and seeps into the soil along the trench sides.]

The biomat-coated soil is less permeable than fresh soil, so incoming effluent will move across the biomat and trickle along the trench bottom to an area where there is little or no biomat growth. (See growth pattern in the diagram on this page.)

Here we will discuss the following:

• What is a septic biomat? - what is the septic drainfield "biomat" layer?
• How the biomat forms: how does the Biomat Form in a septic system effluent absorption system?
• Septic biomat constituents: what is the biomat made from? Septic biomat formation patterns in soil trenches
• How septic biomat formation, though necessary, clogs & ultimately can cause septic drain field clogging and expensive drainfield repairs
• Septic drainfield clogging process: how the soakaway bed or drainage trench fails: the biomat clogging process How to Extend the Life of A Septic Drainfield by Protecting the Biomat

Septic drainfield clogging process: how the soakaway bed or drainage trench fails: the biomat clogging process

Biomats tend to restrict the flow of effluent through the drainfield, but are crucial because they filter out viruses and pathogens. As the biomat develops, the soil infiltration rate decreases. Once the hydraulic loading rate exceeds the soil infiltration rate, ponding starts. At some point wastewater will either back up into the home or break out onto the soil surface.

Septic loading and dye tests look for this "breakout" of effluent on the soil surface - a condition which will occur when the biomat has become so thick that septic effluent no longer percolates through it to the soils below.

If you dig a neat cross section of a traditional leach field trench, and if it was properly constructed, you'll see the perforated effluent pipe surrounded first by gravel, and then the sides of the trench as it was originally cut through the soil. You will also see a 1cm (about 1/2") to 5cm (about 2") thick gray band around the perimeter of the trench - this is where the soil clogging has occurred.

During the septic loading and dye test, an aggressive volume of water, but not exceeding reasonable septic system design parameters, is run into the system, forcing effluent in a failed system to the surface (maybe).

The septic dye itself is a harmless but intense dye - it does not "make anything happen, but its sole purpose is to permit the inspector to distinguish between breakout of (dyed) septic effluent during a septic test and other site water which might be present, say from a spring or surface runoff.

Extend the biomat life - How to Extend the Life of A Septic Drainfield by Protecting the Biomat

Pump the septic tank: Biomat formation cannot and should not be prevented, but septic tank filters, proper organic loading, and proper maintenance of the septic tank can slow the rate at which it forms [thus extending the life of the drainfield].

Septic tank filters prevent excess suspended solids from flowing into the drainfield and can be retrofitted to existing systems.

Washing machine lint filters can reduce the movement of lint into the drainfield. (We've seen promotions for this product but not any studies supporting the effectiveness of this measure.)

Septic tank outlet baffle filters are sold to reduce movement of fine particulates into the leach field. Use of these filters will require a suitable access port and regular maintenance at the septic tank. (We've seen promotions for this product but not any studies supporting the effectiveness of this measure.)

Drywells to handle graywater can reduce the total liquid load on the leach field - a step often taken at sites with limited drainage capacity.

Reduce unnecessary water usage, and in particular, be alert for plumbing fixtures that run continuously such as toilets and leaky faucets.

WATER SOFTENERS & CONDITIONERS should be checked for proper settings for backwash frequency, volume, and salt dose.

Other maintenance that should be performed on the septic system includes having the system inspected and the tank pumped at regular intervals. Pumping the tank allows it to better settle out solids [by maintaining a larger liquid volume or "net free area" in the septic tank], also reducing the organic load to the drainfield.

Magic bullets which promise to restore drainfields are either unlikely to produce any lasting effect or are at risk of contaminating the environment with toxic and perhaps caustic chemicals. These processes are prohibited in some jurisdictions.

As we explain

at SEPTIC DRAINFIELD LIFE

We have seen drain fields still working fine after 25 years and others which failed in the first week of occupancy of a new home. In a properly designed septic absorption field the level of usage of the system, site characteristics such as slope, rock, groundwater level, and soil percolation rate have all been considered.

Barring foul ups such as we discuss in this document, such a field may last from 10 to 20 years. USDA sources assert that a properly operated and maintained ST/SAS (septic tank / soil absorption system) should last at least 20 years.

But it's easy to ruin or shorten the life of a drainfield/leaching bed. In fact the same USDA source states that

Studies reported at an Environmental Protection Agency seminar, Orlando FL, November 1979, show that over half [ST/SAS] fail prematurely due to improper operation or lack of adequate maintenance. Generally, these failures occur when the soil-absorption system [drainfield] becomes clogged.

Preventable clogging, due to a buildup of solids in the [septic] system, is usually extensive enough to require expensive reconstruction of the system. Failures can also cause nearby ground areas, streams, lakes, and water supply systems to become contaminated.

This exposed the public [and USDA, EPA, NPS, FPS, and other government employees] to health threats such as hepatitis, typhoid, diarrhea, and dysentery.

... [ in contrast] The unpreventable failure of the soil-absorption system eventually occurs when growth of the organic material in the wastewater [the biomat] that forms under and along the sides of a drainfield trench] becomes so large [thick] that they plug up the soil.

Similar studies of advanced wastewater treatment systems such as aerobic systems, sand beds, mound systems similarly found that improper or inadequate operation and maintenance were the primary causes of premature failure of those systems as well.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-09-28 - by (mod) -

Ernest

You'll want to read about your "septic pits" starting

at CESSPOOLS

and in particular CESSPOOL FAILURE CRITERIA

Watch out: also see CESSPOOL SAFETY WARNINGS

You will see that once a cesspool has failed it's basically not usable and not repairable; pumping out the pit won't help you one iota except to get a few days of sewage storage before it's filled again.

Unfortunately cesspools or seepage pits also can not adequately treat sewage pathogens as, being deep in the soil, there's insufficient oxygen to support aerobic bacteria, one of the two bacterial types needed. So we're also contaminating groundwater and potentially, nearby drinking water sources.

A sewage clogged cesspit or cesspool will not rejuvenate itself in your lifetime nor mine.

A common step people take to slightly reduce the proper repair cost is to leave the existing pit in place but pipe its top outlet to a new seepage pit, daisychaining the old failed pit to the new one. But where space permits, a real septic tank and drainfield are far more effective and better for the environment.

On 2020-09-28 by Ernest Esquibel - Do you think I should use a root killer in my septic tank?

I have three vertical pits and recently had to have the septic tank pumped out due to getting sewage into my lower level bathroom. i had never had the tank pumped out in 27 years! Stupid me! I also had a septic company install new plastic risers since I had to dig down 14" to find the 12" concrete risers.

The installer said my system is failing. He drained my tank for some repair work and put the sewage into an abandoned v-pit.

I have continued pumping out the sewage into the abandoned v-pit 3 times since then. Do you think if I keep doing this the disposal field will rejuvenate itself, I'm also going to remove a large coral tree.

Do you think I should use a root killer in the v-pits if that could be another issue I have? Thank you so much, Ernie ( negligent homeowner ) .

On 2019-10-06 - by (mod) -

Hi Debbie

You posted this question already at https://inspectapedia.com/septic/Chlorine-in-Septic-Systems.php#FAQ please take a look there

On 2019-10-06 by Debbie

Help! We just bought a new house with a septic system. I grow up on a septic system but there are rules on how to flush the potty correctly. In 1 1/2 years we have had the septic people out to pump the tank but there was a comment that we have a leach field issue. Can and how do I use the pressure washer for the leach field?

On 2018-04-08 - by (mod) -

Hugh

On this page you'll find a live link INDEX to RELATED ARTICLES: ARTICLE INDEX to SEPTIC SYSTEMS -

that article index lists articles giving procedures for SEPTIC TANK PUMPING and DRAINFIELD DIAGNOSIS & REPAIR

On 2018-04-08 by Hugh P Franklin Sr

How to clean out a full septic tank and how to fix leach field

On 2018-03-29 y Randy

I have a leech single line 5'' diameter prob 50-60 ft long. Perforated and surrounded by gravel. I never ever thought to check it. Had a little smell coming up in my bathroom sink. Called and had tank pumped
System untouched for 18 years.now repair man says line has the bio mat grease ECT. Quoted a huge # to wash it out chemicals ECT. This line and everything worked great all that time so thought why not just put a new leach line a few feet along the old one.

On 2013-03-16 - by (mod) -

Thanks for the added info, Jeff.

Indeed, resting a drainfield is a common strategy to extend the drainfield life, though the rest period to recover from excessive biomat growth and clogging can be several years or more. In your case it sounds as if you have no drainfield, but instead a chain of seepage pits (your "drywells") accepting effluent from the septic tank.

Most often seepage pits accepting septic tank effluent are chained together; as the first pit fails (clogs) a second is simply added downstream - so the last one is really doing all the work.

In some new installations including one I installed at our old lab property, where space was too limited for a drainfield and soil had good drainage, we installed a pair of pre-cast concrete seepage pits surrounded by gravel to accept effluent from the septic tank. That system remains effective (for decades) in disposing of effluent, though as I argue in our seepage pit and drywell articles, it does not adequately treat effluent.

IN the case of flushing out any possible effects of a single dose of cleaner, dilution and reinoculation of bacteria through normal use of the septic tank might have better than stopping use, leaving the treated effluent sitting in the tank. But you're probably ok in any event. Keep us posted.

On 2013-03-15 by Jeff Thomson

Yes, normally the 1500 septic tank should be full. But basically all it is getting is a single toilet flush a day (and the toilet tank has 3 bricks in it too) since it was pumped out 6 months ago. All other usage is off-site. I should have mentioned this!

Good to know the hot tub's anti-septic flush wasn't the cause.
Curious how long it takes for the anaerobic/fatty biologics to decay in clay/silty soil?

Thank you for your quick response! Jeff

On 2013-03-14 - by (mod) -

Jeff,
Something doesn't sound quite right here.
In normal use a septic tank is ALWAYS full up to the bottom of the outlet pipe, except for right after the tank has been pumped and cleaned. At normal usage levels a septic tank that has been pumped out is full again in just a few days.

If you know the size of your tank you can figure out how many days it would take for it to re-fill normally. E.g. 1000 gallons at 200g/person daily wastewater flow means one person, 5 days.

So when you open the septic tank and the level is abnormally low I suspect the tank is damaged and leaking.

A hot tub holds 300-500 gallons of water. It just doesn't seem likely to me that 500 gallons of water would explain a septic failure, not would the biocidal effect of a cleaner at normal concentrations as it'd be diluted by normal usage that occurred after that time.

What can happen is that if a drainfield is saturated and in failure, a sudden surge of extra wastewater volume might then show up as a blockage or as seepage out to ground surface.

But none of these would explain why the septic tank would not be full to a normal level.

You need some competent on-site diagnosis.

On 2013-03-14 by Jeff Thomson

My septic drywells failed 6 months ago. 7 months ago I drained my hot tub of bio-cleaning chemicals, which I suspect went straight into the drywells. Up until then, the septic worked fine. I have been barely using the septic system since then.

I took off the septic tank cover today, it is 2/3 of the way to the outlet pipe. If it goes 9 months until waste goes into the dry wells, should they be recovered enough by then? Thanks!

On 2012-06-19 - by (mod) -

Mark, 1-inch diameter drainfield piping would be unusual, and not fuctional in a gravity dosed septic system drainfield. Usually in a conventional gravity drainfield the perforated pipes are 4" to 6" in diameter. And when the drainfield is clogged, brushing the pipe interior won't touch nor fix the clogging - it's occurring at the interior inch or so of soil around the trench.

But you are describing a pressure-distribution system for effluent disposal.

If it's a pressure distribution system, you are already pressurizing the lines each time the pump runs. Since it's almost no cost, indeed you could try brushing the interior of the lines but I am very doubtful that it will help because like the gravity dosing system above, the clog is more likely to be in the soil around the pipes.

I would explore by excavating a cross section of the drainfield trench and pipe near the end of one of your lines to see what the soil looks like. With the line excavated, cycle the dosing pump and watch what happens.

On 2012-06-19 03:44:23.829908 by Mark

Our lateral lines are made from perferated 1-inch pvc pipe and are buried in about 14 inches of soil. If the perforated holes are clogged in the drainfield, can a circular brush be run up the individual lateral lines to clean them out? If I can clear the clogging debris, then I can flush out the lateral lines by engaging the dosing pump. Each lateral line has a point of access at the far end of the line from which to insert a brush and then flush them out.

On 2011-08-15 by Andrew

Yep agreed - I was simply pointing out a strategy which would help avoid Noel's scenario in the first place.

On 2011-08-11 - by (mod) -

Andrew I agree completely that alternate dosing extends the drainfield life as you describe.

A different design suggested by Noel's comment was not a regular alternate dosing system (every dose of effluent switches from one line to another) but rather manual controls that switch effluent from running into one drainfield network to a different one. That approach lets a drainfield rest and recover. The "switch over" usually is handled not by any automagic dosing device but rather by a manual control in the distribution box - often simply swapping an outlet cover from one drain outlet to the other in the D-box.

The more difficult question asked by Noel is just how long it will take for a clogged drainfield to recover if it's left idle. The answer is ... it depends... on quite a few factors: extent of clogging, soil conditions, trench construction including depth, level of aerobic bacteria. For example in Minnesota where drainfields may be eight feet below ground surface, there is very little aerobic bacteria and we lose just about all of the aerobic processing of septic effluent pathogens.

On 2011-08-10 by Andrew

Noel's suggestion points to a useful strategy for prevention of clogging by anaerobic biofilm - that is by maintaining aerobic conditions in the SAS. Designing a system with alternate dosing of two or more discrete effluent application areas is a simple means of promoting aerobic soil conditions.

On 2011-05-14 - by (mod) -

You have the right idea but normally considerably longer than just one year will be needed for the drain field to recover.

On 2011-05-14 by Noel

If one of the trenches in percolation system is not used for say a year, would this cause the biomat to die off, clearing the soil and making the trench functional again?

Reader Question: What is the effect of epsom salts on the septic tank or the biomat: Counteracting the effect of epsom salts in the septic system

2015/10/22 Catherine Holmes Clark said:

I have a severe medical condition which requires me to use 4-5 cups of Epsom Salts (magnesium sulfate) a day in a bath. Also to do a lot of laundry.

I can't get along without these strategies. My new septic system has had an excessive amount of black gunk in the filter the first two years it has been changed. Are my medical strategies causing this? How can I best counteract the effect?

I should have said that after the first year's filter change, I have religiously been using a tie-on filter on my washing machine's exhaust hose. But there is still too much gunk.
I've also been thinking about the fact I use hydrogen peroxide for cleaning surfaces, wondering if this is a problem.

Reply: A diagnostic test & two fixes for rapid sludge formation in the septic tank

First the easy question: a washing machine lint filter won't reduce the level of epsom salts nor affect black goop formation in the septic field; rather it avoids clogging the system with lint.

I'm not sure what the black gunk is, how "excessive" was determined, nor where that gunk was originating. It is normal for septic filters to require more frequent changing than every two years - that may be the root problem. Tell us the septic filter type, manufacturer, and where you live and perhaps we can get an opinion from the filter manufacturer.

Your usage is more than a typical homeowner's bath soak of epsom salts: a typical epsom salt bath soak (recommended by saltworks.com) uses two cups of epsom salt in warm water in a normal sized bath tub (about 40 gallons of water), three times a week, soaking for at least 12 minutes. You are using 2-3 times that dose volume.

I agree that your question is very sensible. Epsom salts can include sulfates, calcium and magnesium; the sulfates might encourage growth of a sulphur-loving bacteria. (See my citations below).

I've read an "builder" opinion that unless you dumped 100 times epsom salts into the septic (500 cups a day) as much as you cite (5 cups a day) there'd be no impact on the septic system, but Id did not see any authoritative source supporting that view. Nevertheless it's not likely that normal household use of epsom salts harms a septic system.

A diagnostic test that would be very helpful would cost you very little

• The next time you prepare your epsom salts bath, collect a sample of the bath water (when the epsom salts are fully dissolved) and ask your local water test lab to give you a report of the salt concentration.
• Calculate or estimate the water volume in your bath tub
• Note the total daily wastewater volume that is discharged into your septic system
• That will let us (or a web page calculator) calculate the concentration of salt discharged into your septic system: remember the epsom salt solution from your bath is diluted by the rest of wastewater discharged into the system each day.

I suspect that we'll find that the total salt concentration in your diluted total wastewater daily discharge will be so low as to be harmless. Certainly Cobleigh found no evidence of a concern (Cobleigh 1911).

The following fixes provide a separate combination of actions that both avoid discharging salty bathwater into the septic (even though it's probably ok) and observing the effect of a change in discharge on the septic tank sludge formation rate

1. A "fix" that might both prove the theory (that epsom salts or the sulphur therein are contributing to slime formation in the septic filter system) would be to route your tub drain to a separate graywater system. Some gardeners even recommend use of epsom salts to soil around rose bushes.
2. A more evidence-based opinion about the effect of epsom salts on your particular septic tank could be obtained by measuring the sludge and scum layer thickness annually for a few years; if nothing else is changed except a re-routing of the epsom-salt-soak bathtub drainage and if you see a difference in the sludge thickness formation rate that woudl be quite credible.

See REDUCE IMPACT of SOFTENER on SEPTIC - for more about reducing the effect of other salts on the septic system.

Citations on research describing effects of epsom salts on water and on septic systems

• Cobleigh, William Merriam, Harry Elwood Morris, and Deane Brit Swingle. Preliminary Report on the Analyses of Montana Waters. Vol. 7. Montana Agricultural College, Experiment Station, 1911.
• Pfost, Donald L., Charles Duane Fulhage, and Stan W. Casteel. "Water quality for livestock drinking." Extension publications (MU) (2001).
• Trumpolt, Clayton W., Michael Crain, Geoffrey D. Cullison, Susan JP Flanagan, Lenny Siegel, and Stephen Lathrop. "Perchlorate: sources, uses, and occurrences in the environment." Remediation Journal 16, no. 1 (2005): 65-89.
• Waring, R.H., Dr., "Report on Absorption of magnesium sulfate (Epsom salts) across the skin", School of Biosciences, University of Birmingham. B15 2TT, U.K.

Question: Review of the Effectiveness of Drainfield shock treatment using BioMat-X

(May 3, 2014) Nathan said:
I have begun researching a product called BioMat-X which is described as a "drain field shock treatment".

It claims to provide "trillions" of enzimes into the drain field to absorb the thgick biomat layer preventing adequate water absorption. It also claims to be beneficial to the environment as it reduces the runoff of untreated sewage.

Is there any scientific basis for this claim? The $185 per gallon cost surely compares favorably with the cost of field replacement. Is it worth the risk to try it?

Reply:

Nathan,

If you want to try the product and if it is not prohibited by your local or state health department (as many septic treatments and additives are indeed prohibitd), I can't object.

The appeal for a magic bullet we could pour into drains, a d-box, septic tank, or drainfield line is very great considering the cost of replacing a failed drainfield.

If we eschew for a moment the illegal, toxic or harmful chemicals used in some processes and just address benign treatments, I remain disappointed that after decades of working in this area and of inviting product marketers to allow us to see independent third party research that shows that the products actually work that invitation has gone un-satisfied.

I've yet to receive supporting data. We have received some reader reports of having used septic field treatment products that did *not* work, leaving me a bit skeptical about online testimonials and white papers produced by product manufacturers or marketing companies.

If we were going to perform a test of a drainfield treatment chemical that was safe to use (as enzymes may well be) I'd like to see the a sound experimental design that allowed examination of the soil in cross section, visually and chemically as well as for percolation rate changes.

It's a difficult thing to test considering that there are many variables: soil conditions, septic use, weather, and disturbance of the soil just to look at it.

My OPINION is that the products generally are not effective.

If you'd like to give it a try, why not purchase a single gallon and obtain the seller's advice on how to use it in a single small drainfield area that you might then be able to monitor for changes in the soil percolation rate?

Nathan, I've repeated this discussion and added more comments in a companion article that you should see on drainfield restorer chemicals and treatments

DRAINFIELD RESTORATION APPROACHES

keep us posted

Daniel

Question: biomat break-down time or rate in an un-used septic field

(June 10, 2014) bob said:
If a field remains unused, I presume the biomat will breakdown, how long a rest would it need to restore proper function? What variables will affect this length of time?

Reply:

Bob, good question.

Several years, possibly much longer will be needed. Some of the variables are

- original thickness of the biomaterial

- soil moisture

- depth of the biomat (deeper =longer)

- soil chemistry

- other soil properties, sand vs clay for example

- disposal in the field of salts, grease, oil, detergents, chemicals

Question: massive root invasion problems in the septic field

(Mar 29, 2015) FedupFred said:
Pulling out my hair because it has only been 7 yrs since our new system (2-1,000 gal tanks + 2" line pump to field that is 18'x50'and VERY deep) we are only 2 ppl in the house with ALL high efficient appliances.

Did a video snake and revealed massive root invasion, having the d-box and lines to chambers(pieces of s#it in my opinion) hydro-jetted and then root killer foaming done this week. Hoping that this gets everything working properly without another break out of water on the top of the field.

Also just added a DIY aeration set-up to my liquid tank in case the is too much bio-mat forming.

Reply:

Fedup

I'd pull my hair too if I had any left. It sounds to me as if

1. the original installation was faulty as sound pipe joints ought not invite roots -unless you mean the roots are in the drainfield

2. if roots are in the drainfield then you've got trees or plants where they don't belong and no amount of hydrojetting is going to fix that

3. adding an aerator to a septic system not completely designed for aerobic treatment may be inviting a disaster. If you keep the solids in the septic tank agitated and broken up by an add-on aerator these easily flow out into and clog and destroy the drainfield.

You'd need outlet filters at the tank exit (frequent maintenance needed) or a multiple tank or settling chamber system for what you are doing to work. - DF

(Apr 17, 2015) ekdigdirt said:

I'll second what DanJoe said (especially about agitating the solids in the tank with an aerator) and ask the follow-up questions of whether you have a single compartment septic tank or multiple compartments (usually it's a 3-compartment tank if you have an aerator), and whether the end of the field is vented. The depth of the SAS is integral in proper functioning, and usually anything over 36" deep wouldn't be approved - at least here in MA. There shouldn't be any deep-rooted vegetation less than 10' around the perimeter of the leachfield.

A side-question: Is your house new? And if so, did the contractors rinse their paintbrushes in the inside plumbing? Latex paint is perfect for clogging a leachfield, especially with infiltrators.

Historically, if this is the case, the only fix is to take out the infiltrator chambers, scrape out the 6 or 8" of clogged sand, put down the same amount of new, clean sand, and then either pressure wash the infiltrators (if you can do it without breaking them) or put down new ones. Much much cheaper than installation of a whole new system, but still not cheap in and of itself. Good luck.

...

Continue reading  at CHLORINE IN SEPTIC WASTEWATER or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• AEROBIC ATU SEPTIC FAILURE RATES, COSTS
• DISPOSAL vs TREATMENT - getting rid of effluent isn't the same as avoiding contamination
• SEPTIC DRAINFIELD INSPECTION & TEST - home
• SEPTIC DRAINFIELD LIFE
• SEPTIC DRAINFIELD LOCATION
• SEPTIC DRAINFIELD RESTORERS?
• SEPTIC DYE TEST PROCEDURE for testing septic system function.
• SEPTIC LIFE EXPECTANCY
• SEPTIC TANK, HOW TO FIND
• SEPTIC TESTS: DYE & LOADING TESTS
• SEPTIC SYSTEM ODORS
• SEPTIC TANK & SYSTEM CARE BASICS for specific advice about the septic tank

Suggested citation for this web page

BIOMAT FORMATION & SEPTIC LIFE at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to SEPTIC SYSTEMS

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