Download Order Form


CONTACT US

info@landperc.com

Phone (239) 274-6818

How Do Septic Systems Work?

What are General Septic Maintenance Tips?

What is a Biomat?

How Does the Biomat Form?

What are Biomat Constituents?

What is the Biomat Formation Pattern in Soil?

What is the Biomat Clogging Process?

How Do You Extend the Drainfield Life?

What are Some Septic System Installation Secrets?

How Long Should a Septic System Last?

What are Signs of a Failing Septic System?

What if My System Fails?

What are Some Advantages of a Septic System Over Sewer?



How Do Septic Systems Work?

The septic system is a natural method of treatment and disposal of household wastes for those homeowners who are not part of a municipal sewage system. A septic system works by allowing waste water to separate into layers and begin the process of decomposition while being contained within the septic tank. Bacteria, which are naturally present in all septic systems, begin to digest the solids that have settled to the bottom of the tank, transforming up to 50 percent of these solids into liquids and gases. When liquids within the tank rise to the level of the outflow pipe, they enter the drainage system. This outflow, or effluent, is then distributed throughout the drain field through a series of subsurface pipes. Final treatment of the effluent occurs here as the soil absorbs and filters the liquid and microbes break down the rest of the waste into harmless material.

Most septic systems are conventional systems that use gravity to distribute the effluent from the tank. When site conditions are not appropriate for a conventional system, other types of systems, such as low pressure distribution or mound systems are sometimes used.

Septic systems cannot dispose of all the material that enters the system. Solids that are not broken down by bacteria begin to accumulate in the septic tank and eventually need to be removed. The most common reason for system failure is not having these solids removed on a regular basis. When the holding tank is not pumped out frequently enough, the solids can enter the pipes leading to and from the tank. This can cause sewage to back up into the house or cause the drainage system to fail as the pipes and soil become congested. These problems are often costly to fix, pose a danger to public health, and are a significant source of water pollution. Seepage from inadequate or failing septic systems can contaminate both ground and surface waters.

Wastewater contains several undesirable pollutants. Pathogens such as viruses or bacteria can enter drinking water supplies creating a potential health hazard. Nutrients and organic matter entering waterways can lead to tremendous growth in the quantity of aquatic microorganisms. Metabolic activity of these microbes can reduce oxygen levels in the water causing aquatic life to suffocate.

Back to Top

What are General Septic Maintenance Tips?

Septic system maintenance is actually pretty easy to understand. When a system fails, the tank itself doesn't fail- the drainfield soil fails. In most cases the soil fails when it gets plugged up with solids and won't allow liquid to pass through it. For example, it can get plugged with solids from the tank if the tank hasn't been pumped, or with lint from a washing machine. Now for your solutions:

1. Use a Washing Machine Filter

Did you know that washing machines are a leading cause of septic system failure? The primary culprit is lint generated by washing machines, which clogs the soil in drain fields. Did you know that a typical family washing machine produces enough lint each year to carpet and entire living room floor! Lint screens and nylon traps found in hardware stores trap 5% or less of these particles. Because they are so light and small, the lint particles do not settle out in the septic tank. Instead, they stay in suspension and are flushed out to the drain field, where they plug up the pores of the soil bed.

To compound the problem, much of our clothing is now manufactured with synthetic materials such as polyester and nylon. These substances are not biodegradable, and will not break down in a septic system. Instead, they accumulate and plug the soil. Once these materials enter the soil, there is no way to remove them.

2. Avoid Excessive Water Use

You can also damage your septic system by doing a large number of laundry loads in a short period of time. In standard septic systems, solid materials settle in the tank, while effluent flows out into the ground. If you put more water into the system than it is built to handle, the high volume of water will flood your system, and can also stir up and flush solids out of the tank into the drain field (in fact, septic pumpers use water from their hoses to help break up solids in your tank before pumping them out). A typical washing machine can use up to 60 gallons of water per wash load. On a heavy day you can easily put 400, 500 or 600 gallons of water through the system in a few hours. The solution is to spread out your water use. Do one or two loads of laundry per day, rather than 10-12 loads on Saturday morning. Water softeners can also damage your system by putting too much water through the septic system. These devices can put several hundred gallons of water down the drain every week, water that is not contaminated and does not need to go through the treatment process.

There are a couple solutions to this problem. You can upgrade your softener with a newer efficient model that uses less water and regenerates on demand, instead of a timer system that regenerates whether you use water or not.

3. Prevent Solids from Leaving the Tank

First of all, you should get your tank pumped on a regular basis to prevent excessive accumulation of solids in the tank. Under normal conditions, you should have the tank inspected and pumped every 2-3 years. Very important: tanks should be pumped and inspected through the manhole cover, not the inspection pipe. Your septic contractor should also install an effluent filter in the exit baffle of the tank. Effluent filters stop the larger solids from getting out to the drainfield. They are cleaned out every few years when you have your tank pumped. Effluent filters are cheap insurance and along with a washing machine filter, one of the best things you can do to protect your system.

4. Use Household Cleaning Products

Excessive use of these products can contribute to septic system failure. If you do over 5 loads a week containing bleach, problems could arise. Avoid powdered detergents as they contain plastic fillers that can plug up your lines and drain field. Also, be careful with harsh automatic toilet bowl cleaners, which have put quite a few systems out of commission.

5. Should I Use a Separate System for My Washing Machine?

Some people say you should use a separate system for your washing machine, called a laundry interceptor. However, this is not necessary and in fact undesirable. Washing machines should discharge into the regular system because it actually works better than discharging into its own system. In order to work, septic systems require bacteria colonies which break down biodegradable matter. These bacteria require "food" which is found in our wastewater, but not in detergent. Without "food" these bacteria colonies die out and the system fails. Many people who have installed these systems have found this out the hard way. A research project conducted in several east coast states utilized some rather high tech systems for washing machine discharge and many began failing in as little as eight months.

An additional concern with septic fields is the build up of biomat in the soil

Biomat consists of microorganisms and their waste products. It forms where the drainfield bottom and soil contact each other. A small amount of biomat is normal; however, if the wastewater contains solids, then the organisms in the biomat will feed on the increased amount of nutrients and the layer will thicken. As the biomat thickens, the flow of water out of the trench is slowed. The drainfield will fill and eventually the wastewater will surface to the ground. To protect your field against excessive biomat formation, pump the tank every 2 to 3 years.

The below picture is a side view of two septic trenches showing biomat growth. The top trench shows normal biomat growth. The bottom trench has thicker biomat growth and prevents the wastewater from draining into the soil. Correction of these problems can be costly. Hydrojetting may remove pipe blockages, but a septic field repair or replacement is needed to correct a biomat problem. Hydrojetting will not remove a biomat build up. The following information can help prevent these problems.

Maintenance Tips:

Do:

  • Divert surface runoff water from roofs, patios, driveways and other areas away from your drainfield.
  • Have your septic tank pumped regularly. It should also be inspected for leaks, cracks and to make sure the exit baffle is in place.
  • Install lint and effluent filters.
  • Spread out your laundry loads.
  • Compost your garbage or put it in the trash.

Don't:

  • Use a garbage disposal.
  • These appliances normally double the amount of solids added to the tank!
  • Flush sanitary napkins, disposable diapers or other non-biodegradable products into your system.
  • Dump solvents, oils, paint thinners, disinfectants, pesticides or poisons down the drain as they can disrupt the treatment process and contaminate the groundwater.
  • Dig in your drainfield or build anything over it.
  • Drive over your drainfield or compact the soil in any way.
  • Plant trees or shrubbery close to the septic system, because the roots can get in the lines and plug them. Grass is the only thing that should be planted on or near a drainfield.
Back to Top

What is a Biomat?

The biomat is a bacteria layer which forms in soil below and around the bottom of the drainfield 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) 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.

Back to Top

How Does the Biomat Form?

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.

Back to Top

What are Biomat Constituents?

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.

Back to Top

What is the Biomat Formation Pattern in Soil?

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.)

Back to Top

What is 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.

Back to Top

How Do You Extend the Drainfield Life?

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 filtersprevent excess suspended solids from flowing into the drainfield and can be retrofitted to existing systems.

Washing machine lint filterscan 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 filtersare 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.)

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

Water Softenersshould 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 bulletswhich 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.

Back to Top

What are Some Septic System Installation Secrets?

Size of the lot (a small lot can make regular septic system installation difficult, even impossible).

The depth of teh slightly limited soil.

The perc rate of the soil (slow soils can make installing a regular septic system difficult, even impossible).

The depth to the seasonal high water tables.

Believe it or not, it is very important to first pick out the ideal location for your septic system BEFORE deciding where to put your house, well, etc.

The septic system installation process will vary from state to state and county to county. If you are considering buying a property that will have a septic system you should contact the Health Department in that area and talk to the person that deals with that area. Ask them what the typical conditions are in that area. They can not give you the exact information on that particular lot but they should be able to give you a general answer.

To design your septic system you will need a septic designer. They will know all of the local regulations and particulars for the county you are building in.

Now you want to find a contractor to install your septic system. One way to narrow down your search is to ask the Health Department for a list of certified contractors that work in that area. Then you tell them you want to do this right by getting a contractor that is going to do the job properly and not take you to the cleaners. Ask them who they would use if they were going to have some septic work done. They can not tell you who not to use because that is preventing someone from making a living, but they will often point out the better ones because they know a bad contractor putting in bad systems will make their job tougher.

Again the legal steps will vary but best way (and the way it should be) is to contact some systems designers/installers in that area and ask them the same questions on what types and the average costs of the systems being used. Then hire a contractor to do a design.

This design process will cost you $500 to $900 but it will tell you what you will be looking at before you buy the property (and a few hundred dollars is a small price to pay when you are looking at investing several hundred thousand dollars in building a home). Now you can decide if you want to purchase the property and move on to the next step, which is purchasing the property and building the house.

You should also have the septic designer out to assess the site before you chose your location of the house. You may want the house right in the middle of the lot, however the location of the house may have an impact on the type of system you end up with. Get the designers input and it could save you a considerable amount of money on the type and cost of the septic system.

This design should then be presented to the county inspector for approval. They will look it over and if they think it will fly, they approve it. If not they will tell the designer to make the necessary changes before they approve it.

Then the system is installed and the county inspector will come out to check if the system was installed according to the approved design.

And I will reiterate this point, when it comes to the contractors and government agencies, the knowledge, skill levels and bureaucratic process will vary around the country. Some states are very progressive. They require the contractors and inspectors to be well trained and certified if they are going to be dealing with septic systems. They are also open to new technologies available to solve problem sites.

Back to Top

How Long Should a Septic System Last?

You can expect a conventional septic system, such as that being described here, to last about 16-18 years. Some systems last much longer and some systems can fail earlier. Other things can also affect the life of a septic system. For example, a system may have been providing satisfactory service for a previous owner for many years, only to fail shortly after you have bought the house. If the previous owners were a working couple with no children, the system was probably not heavily used; if yours is a family of six, the added load could push a marginal system over the edge and into failure.

Back to Top

What are Signs of a Failing Septic System?

Sewage backup into the home is one possible sign of a failing system. However, backup can also be simply the result of a blockage somewhere between the house and the septic tank (this is relatively easy to fix).

Another possible sign of failure is a smell of sewage outside the house. If this smell is more noticeable after a lot of water has been put into the system - multiple showers or several loads of laundry (if the laundry waste discharges into the septic system), for example - this may be an indication that the drainfield is failing. The smell may also be accompanied by a "spongy" feeling in some areas of the drainfield or near the septic tank.

The "spongy" feel may be caused by water and waste being pushed to or near ground level. If ponding water is also seen, this is called "breakthrough" and is an almost positive indication of failure of one or more parts of the system. This smell, however, can also originate at the plumbing vent. In either case, further investigation is warranted.

Dye Testing: If you see such signs, a dye test may confirm your suspicions. For this test, a special strong dye is put in the system - usually by flushing it down the toilet. A significant amount of water is then washed into the system.

If there is "breakthrough", the dye will become visible on the ground surface. If the dye is seen on the surface, this would be a very strong indication that the system has failed. Your Home Inspector, a licensed professional engineer, or a septic system contractor can usually perform this test.

Back to Top

What if My System Fails?

In quite a few cases, a tune-up can fix your system and you can avoid the high costs of replacing the system. This tuneup includes properly pumping the tank, cleaning (jetting) the drainfield lines, and installing washing machine and effluent filters. If these measures are not sufficient, some failed systems can be rejuvenated by fracturing the soil. This process utilizes a hollow tube inserted into the soil, then a 300 pound blast or air is injected into the soil creating thousands of tiny fissures. These fissures allow the drainfield to drain, creating an oxygen atmosphere and the aerobic bacterial colonies to repopulate. Aerobic bacteria, which require oxygen, typically live in the top 26 inches of the drainfield and process waste much more quickly than anaerobic bacteria. This process can be performed in a matter of hours with no digging or damage to the yard.

Back to Top

What are Some Advantages of a Septic System Over Sewer?

Unless you live in a highly populated area a septic system is your best option. If properly installed and maintained, your system should cost far less to maintain because there are no monthly sewer fees, only the less expensive cost of pumping out the tank every two or three years, although a limited system or one with very heavy use may require more frequent pumping. A septic system treats the effluent naturally and lets the water seep into the ground, keeping moisture on site to help plants grow and to gradually replenish the water supply. In contrast, sewers treat the effluent and release it to a river. Areas with septic systems require larger house lots, so there is more room for gardens, playing, and a more rural feeling.

The facts are that a properly installed and maintained septic system is less expensive to run than a hookup to a sewer system with monthly fees; and the septic system keeps the water used in the area, where it is cleansed and reclaimed over time, thus making it available for a constantly replenished groundwater and drinking water supply.

Back to Top