These are some "Frequently Asked Questions" that Coastal Plains Environmental Group has handled, regarding septic systems, Alternative treatment systems and maintenance of onsite wastewater treatment.    If you have other questions, please email them to us, and we will try to answer them to the best of our ability.   

Our Email address is: krdavis@cpegllc.com. Thank You.



       Why do I have to have my system pumped every five years?
       Why does my neighbor have a "conventional" system and I need an "alternative" system?
       What is an Aerobic Treatment Unit? (ATU)
       What is a Media Filter? (PBF, Sand Filter, Peat Moss, etc.)
       What is an AOSE and why won't the health department evaluate my lot?
       Can I use a garbage disposal with a septic system?
       What about these Septic Tank additives?
       Why do we smell a Septic Odor in our back yard?
       I have "hard water" and want to add a water softener to my house.




Why do I have to have my system pumped every five years?


In Virginia the five year mandatory pump out is required if you reside in the Chesapeake Bay Preservation Area.  This law was actually enacted in the early 1990's, and is only now beginning to be enforced.

However, it is a good idea to have your septic tank pumped out periodically.  Solids are supposed to settle to the bottom of the septic tank, and oil, grease and scum are supposed to float to the top.  The scum layer (top) and the sludge layer (bottom) will continue to grow over the years.    Eventually, these two layers can become so thick that they interfere with the proper operation of the system, and allow solids, oil, grease, or scum to get out to the disposal area.

If you live outside the Chesapeake Bay Preservation Area in Virginia, you should have someone check your sludge and scum layers periodically (once every two years minimum) to determine if the levels have become thick enough or deep enough to warrant a pump out.   Some systems due to use, may require a more frequent pump out than once every five years.    Others, may require less.    However, if you reside in the CBPA, you will have to have your system pumped once every five years regardless, as it is the law.

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Why does my neighbor have a "conventional" system and I need an "alternative" system?


Well, a lot depends upon when your neighbor had his system permitted or installed.    In July 2000, Virginia made radical changes to the rules and regulations governing onsite sewage disposal.    Designers of onsite systems used to be able to achieve a stand-off to indicators of seasonal water table based upon the estimated percolation rate of the soil.    This in effect was a "sliding" scale, allowing you to install the disposal system closer to seasonal water table in a soil with a faster perc. rate.

The new regulations required a minimum installation depth of eighteen (18) inches for a disposal field, and a minimum separation distance of eighteen (18) inches to seasonal water table or restrictions.    So basically, if you wanted to install a "conventional" gravity drain field, you needed to have thirty-six (36) inches of good dirt in the disposal area.

If you didn't have thirty-six inches of good dirt, lets say you only had thirty-four inches, then the new regulations require that you either install the disposal field shallower than eighteen inches, or obtain a stand-off to water table or restriction that was less than eighteen inches.    In either instance, the new regulations allow you to achieve these changes IF you use "secondary" treated effluent.    Secondary treated effluent can be achieved by use of either Aerobic Treatment units, or Packed Bed Filter units or in other words, an "Alternative" septic system.

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What is an Aerobic Treatment Unit? (ATU)


To try to describe it as simply as possible, an ATU is a second tank or compartment to your treatment tank (septic tank), that has a blower or some form of agitator that injects air into the sewage to promote bacterial growth.    Basically, there is little to no oxygen in your primary treatment tank, so very few bacteria can grow and live there.    Hence you get that "septic odor" when you open the tanks up, as your primary treatment tank is anaerobic.

Using some form of blower unit, be it a small air compressor, ventilation blower, bubbler, or agitator, we increase the oxygen content of the sewage to allow more bacteria colonies to grow.    The active bacteria then feed on the sewage and digest it, releasing water and carbon dioxide as a waste product.    A properly operating Aerobic Treatment Unit should never be giving off a "septic" odor, but smell more like a damp basement.

These systems should be looked at by a qualified maintenance technician at least twice a year, and in some instances quarterly.   

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What is a Media Filter? (PBF, Sand Filter, Peat Moss, etc.)


A media filter, also referred to as a packed bed filter, uses some form of material (sand, glass, peat moss, synthetic textile) to act as both a filter, and as a place to grow bacteria.    These systems may be single pass, meaning that they pass the sewage through them one time, or multi-pass, meaning that they recirculate a certain percentage of the sewage back to the treatment tank to be treated and filtered again.    An advantage to this type of treatment system is that it produces a consistent high quality effluent that may be so clear that you would think it is water.

The system usually has several mechanical components, including one or two pumps, some form of control to dose the filter equally over a 24 hour period, and some form of counter that tells the service provider how often and how long the pump or dosing siphon has operated.    The type of media or material used, should allow for air movement through the material, and should remain moist, but not saturated.    If you see this type of system with water standing on top of it, then there is something seriously wrong.   

These systems should be looked at by a qualified maintenance technician at least once per year, and in some instances, twice a year.   

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What is an AOSE and why won't the health department evaluate my lot?


Your local health department Environmental Health Specialists don't just evaluate property for onsite sewage disposal systems.    They also inspect the local restaurants, campgrounds, hotels, motels, respond to general environmental complaints, perform investigations into animal bites, conduct education and training seminars for the general public, and perform disease surveillance.    Their staffing is limited, and their time is extremely valuable.

With all of their duties and responsibilities, they sometimes can't spend as much time on your property as they need to perform a complete evaluation.    Also, their work is prioritized, with those job responsibilities having a high impact on the public health having a higher priority than finding an onsite sewage disposal system on a vacant lot.    There is not a lot of public health issues at stake, on a property where no one is living yet.    Also, your lot may require an "alternative" wastewater treatment system.    The health department must remain impartial, so they cannot recommend one type of treatment system over another.    Hence, they refer you to an AOSE (Authorized Onsite Soil Evaluator).

An AOSE can spend more time on your property, and evaluate the property fully, whereas the local health department personnel may have other more pressing issues to pursue and time constraints as to how long it takes to process other applications, or perform other inspections.    Yes, an AOSE is certainly more expensive than the local health department. ;   Due to time constraints, the local health department may only look at one or two sites on your property.    If neither of these sites meet the current Sewage Handling and Disposal Regulations, your lot may be denied.    A consultant on the other hand is getting paid to find you an onsite sewage disposal system.    If that means he or she have to evaluate ten different sites to find suitable soils, then that is what has to be done.    The AOSE isn't under the time constraints that govern the local health department.

You can find a listing of all current AOSE's at the health department's web site www.vdh.state.va.us/onsite/AOSE.    All AOSE's have to be certified by the Health Department, and their work is reviewed by both the local health department office and periodically by the central office in Richmond.

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Can I use a garbage disposal with a septic system?


In almost every instance, I say NO! ... when you use a garbage disposal, you grind up food particles into small pieces.    These pieces stay suspended in the liquid of your treatment tank, and don't settle to the bottom as rapidly as larger particles.    So, there is a great possibility that these "suspended solids" are getting out of the treatment tank and into your disposal field.

The treatment tank is designed to provide time for suspended solids to either settle to the bottom of the tank, or float to the top.    There is a " T ", also referred to as a baffle, at the outlet of the septic tank which helps keep the solids and scum in the tank where it belongs.    When you finely grind food particles and suspend them in the liquid, they will get out to the disposal field and become food for the biological mat (biomat) that is developing out there.    Eventually, the increased food supply and increased size of the biomat will lead to a failure of the sewage disposal system.

You can help this situation by adding an "effluent filter" to the outlet " T " of the septic tank.    They come in various sizes and will filter up to 1/32" particles and keep them in the treatment tank.    Also, if you have a "Packed Bed Media Filter" or PBF, this will help keep the solids out of the disposal field.    But, there is a cost to pay.    If you have an effluent filter installed, or have a Media Filter as your secondary treatment system, and use a garbage disposal, you should have an experienced maintenance provider check your system at least annually.   The suspended particles may not be getting out to your disposal field, but they can be interfering with the proper operation of your alternative treatment system.

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What about these Septic Tank additives?


Many products are sold that claim to make old systems like new.    Other products claim to eliminate the need to pump out the treatment tank, or are billed as "septic system safe".    These products usually contain yeast, bacteria, enzymes, or chemical degreasers.

Some of the solids in the treatment tank are sand, grit, bits of plastic and similar materials.    No enzyme or bacteria can digest these.    There are even some organic solids that cannot be broken down in the treatment tank.    Hence they accumulate.    When you add commercial products to your system, the bacteria they add must compete with bacteria that are adapted to living in your treatment tank.    These adapted bacteria have the home field advantage.    The newly added organisms can't compete and become dinner for the resident organisms.

Enzymes on the other hand, unlike bacteria, are not living and cannot reproduce.    When they are added to a system, they will not increase in number.    Most treatment tanks are 1,000 gallons or larger, and the quantity of enzymes added is generally too low to be helpful.

So far, no additive has been proven effective in a controlled scientific study.   Many company's make claims that their additives work, and may even be able to provide you with a brochure that says they have been laboratory tested and proven, but it was their lab!

In short, adding enzymes or bacteria usually won't cause a problem, but they won't help either.    The solution is simple.    Pump your tank every three to five years, and if you have an "alternative" system, arrange for annual maintenance and monitoring.    This solution is easy, safe, and often cheaper than continually buying septic tank additives.

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Why do we smell a Septic Odor in our backyard?


Odor problems are one of the hardest, most difficult, and sometimes impossible situations to resolve.   All treatment tanks (septic, processing, etc.) should be vented backwards through the house vent which terminates above the roof.   A lot of times, people complain about odors and if you can get them to keep a log, we can sometimes trace it back to weather conditions.   A low pressure system develops, and instead of the odors dissipating above the roof of the house, they are forced downwards.    Since most bathrooms are located to the rear of the house, and the typical roof stack vent is located at the rear of the house, we get a correlation between the odors being strongest there.

Sewage by itself is extremely corrosive, and one by-product is Hydrogen Sulfide gas.    This gas if left in the tank and not vented somehow will cause rapid deterioration of the concrete structure.   If for some reason the building sewer has a dip in it, and is not allowing the gas to ventilate through the roof stack as designed, then the gas may vent from the tank in some other manner such as through manhole openings.

The other thing to consider is that the odor(s) aren't even coming from your residence.   If a neighborhood is served by onsite wastewater treatment systems, it could well be a neighbor's treatment tank or dispersal field that is causing the problem, particularly if they are up hill or up wind of your residence.

Someone experienced with the design and installation of treatment systems would probably be your best bet to take a look at this.   They would have to locate all treatment components (treatment tank, distribution system and dispersal field) and evaluate where and why the odor is occurring.   Not always an easy thing to do, and may take repeated visits to discover the problem and effect a cure. The homeowner could smell the odor now, and by the time the evaluator gets there, it is gone.

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I have Hard Water and want to add a water softener/


This is another tough question to answer.  First, lets examine briefly how a water softener works.  The majority of water softeners installed in a residence use some form of salt solution (brine) to actively remove unwanted chemicals or elements from the water well supply being used.  Unwanted elements to be removed may include Iron, Manganese, Copper, etc.  They also may partially alter the pH and reduce the "hardness" of the water.  To truly determine what type of water treatment system you need, you must have the well water tested.  Periodically, the system will need to "re-charge" itself.  Through a timer unit, the system goes through a backwash cycle where it flushes out the accumulated chemicals and/or elements, and excess brine.  It then basically reloads itself and begins treating your water again.  Frequently, this discharge is plumbed directly into the building sewer, where it then ends up in your onsite wastewater treatment system.

Lots of studies have been funded by the manufacturers of water treatment technology to prove that they are safe with onsite sewage disposal systems.  But, anecdotal evidence from those of us in the maintenance industry show that problems occur and proper wastewater treatment is disrupted when a water treatment system using brine discharges to the building sewer.   

Water treatment discharge has not come in contact with human waste, and has not been used for food preparation or bathing.   Therefore, in most states water treatment discharge is not considered to be sewage and does not need to be connected to the building sewer.  A number of manufacturers of wastewater treatment technology will consider all warranties null and void should such a system discharge to the wastewater treatment device.

If you truly have a need for a water treatment system, my advice would be to have it discharge either to the ground surface or to its own small dispersal trench, not into the building sewer.

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