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If a house
is not connected to a municipal sewer system chances are it possess
some type of septic system to treat and disperse the wastewater
created by bathrooms, kitchens and the laundry room. Proper maintenance
of these systems is necessary to avoid polluting ground water and
the high cost of having to replace theses systems.
Most septic systems possess the same general
characteristics of an underground, enclosed septic tank and some
sort of soil absorption system to allow the effluent to be released
into the soil where it is treated by natural processes. (Cesspool
will not be discussed because most jurisdictions greatly restrict
or ban their use). Because the creation and operation of these systems
is governed by established codes, your local health department is
a very good source for information regarding your particular system,
they may even be able to tell you who installed it and when.
The first component of a septic system that
needs to be addressed is the septic tank. All wastewater from the
house enters the septic. If the tank cannot be located, look for
a sewer pipe exiting the house in the basement or crawl space. Outside
of the house near the exit of the pipe is where the tank is most
probably located. Some tanks have a 4 inch clean out or inspection
port marking the top of the tank. Look for plastic piping capped
with a square cap, the cap usually has a small square nub on top
used to wrench open the cap. Some obvious signs of placement of
the septic tank are depressions in the ground, a slightly mounded
patch of ground, an area that is difficult to grow grass or an area
where snow (if applicable) melts quicker. Septic tanks are usually
rectangular in shape and can be made of concrete, fiberglass or
steel. While fiberglass and concrete tanks may last up to 50 years,
steel tanks may last ten years but have been known to collapse in
five years. If a property contains a steel tank, a thorough inspection
of the tank should be conducted. Depending on the size of the tank
and number of bedrooms in a house septic tanks can range between
1,000 to 2,000 liquid gallons. Regardless of the material the tank
is made of they each have the same basic components,
The purpose of a septic tank is to separate
solid (sludge) from the liquid wastes (effluent) and lighter solids
(scum). Bacteria in the wastewater digest the sludge and scum and
liquefy the waste products into gases and water. The gases leave
via a vent, normally through the roof of the house, while the liquid
is then dispersed by the drainage system and broken down by naturally
occurring bacteria in the ground. The solids are collected in the
bottom of the tank where it is eventually pumped by a certified
septic waste removal company. To accomplish the separation between
solids and liquids, the septic tank has either baffles or a tee
that allows the effluent to flow out while keeping the solids trapped
in the bottom of the tank. Most newer septic tanks have an inspection
or cleanout pipe that will allow inspection of the tank. When looking
down into the tank, the top of the tee or baffles should be visible.
If they are not visible, it is possible that either they cannot
be seen or they are covered over by the scum or wastewater. If this
is the case, chances are the distribution pipe is clogged. This
is a common problem with septic systems and a professional should
be called to clear out the blockage.
From the septic tank, the effluent has to
be dispersed of in approved manner. In almost all cases, the effluent
is dispersed of into the soil where naturally occurring bacteria
in the ground treat the waste. The three most common Soil Absorption
systems are the Trench system (drain or leech fields), Seepage pits
(dry wells), or Mound systems. A distribution box maybe found if
more than one trench or seepage pit are required to equally spread
the effluent to each part of the system. Depending on the geographical
location, any one of the three types of systems maybe in place.
A standard procedure to determine which system should be in place
is the Percolation (perc) test. Very simply stated, a pit is dug
in the ground and a known amount of water is introduced. The ground
must absorb the water in a certain period of time. If the water
is absorbed within the allotted time the ground is said to perc,
meaning the soil is capable of handling the liquid produced by the
septic system. If the ground does not perc either another location
must be chosen or a mound system may be required to disperse the
effluent. Whatever the circumstances, all three systems have the
same purpose; to disperse the effluent in a manner that will allow
the naturally occurring bacteria in the ground to break down the
waste into safe substances.
The Trench system or drain field as it is
commonly known is very simply a perforated pipe or pipes leading
from the septic tank through a layer of gravel where the effluent
can be safely leeched into the ground without contaminating groundwater
supplies or adjacent bodies of water. Normally, these distribution
pipes are beneath one to fifteen feet of backfill, the surface of
this being the yard. Between the backfill is a barrier material
sitting on top of between 3 / 4 and 2 1/2 inches of gravel. The
distribution pipe runs through the middle of the gravel. All of
this must sit at least four feet above water table or bedrock. The
width of all of this is between one and three feet. (All of the
above numbers vary according to local codes; call the local health
department for more specific information).
Another popular type of soil dispersion
system is the Seepage pit or dry well as it is commonly called.
Leading from the septic tank is a distribution pipe leading into
either a dug or bored well. The well is lined with either gravel
or blocks with open joints. The bottom of the pit is covered with
between six to twelve inches of 3 / 4 to 2 1 / 2 inches of clean
gravel. Covering the well is a reinforced concrete cover with either
an inspection pipe leading out of the top. (All of the above numbers
vary according to local codes; call your local health department
for more information). Dry wells are common on properties that have
small yards or yards that back to cliffs or other obstructions that
prevent the use of a drain field.
The third type of soil dispersion system
is the mound system. These are used almost exclusively when the
ground will not perc. This may be caused by either a high water
table or a rock substrate that prevents purifying the wastewater
completely. Whatever the situation, the mound system is created
to disperse the effluent into a man made mound that is built above
ground. Leading from the septic tank, the wastewater is carried
into a chamber where there is a pump that pushes it into the mound.
The top of the mound is crowned with a cap (usually underneath a
layer of grass and top soil). Underneath the cap is a buffer of
straw, hay, or fabric sitting on an absorption bed where the wastewater
enters the mound. Although different companies utilize different
methods, for the most part there is some type of fill or material
that filters the effluent as it is pulled down the mound via gravity.
At ground level is the earth is plowed to allow easier dispersion
into the permeable soil underneath. A note about these systems:
Routine inspection of the pump from the tank to the mound should
be conducted. If the pump fails, the septic tank can fill and cause
a backup. There should be some cover over the accessible chamber
where the pump sits so that it can be inspected.
Proper use of your system as well as routine
care and maintenance of your system are very important in getting
a long life out of the systems require periodic pumping of the septic
system every three to five years (more frequently for systems under
heavy use). Be sure that the septic company chosen pumps both the
sludge and the wastewater and will dispose of it in a proper fashion.
Because prices will vary widely, it is recommended that a couple
of companies are called and the prices are compared. Make sure that
they will also inspect the inlet and outlet baffles or tees when
they come to do the pump out. Have them repaired if there are any
problems. Keep accurate records for all maintenance and repairs
conducted.
If the following are followed, the useful
life of the septic system can be greatly extended. It is important
that the septic system location is known so that it may be monitored.
Heavy vehicles should stay off of the system as they can cause damage
to underground piping and components. Do not build over the drainage
system nor plant trees or shrubs over it as the roots can clog drain
lines. Rain water runoff from the house, spouts, sump pumps or any
either water diverting devices should be kept away from the septic
area to avoid overloading the system. Steps should also be taken
to reduce sludge build-up in the system including; pumping of the
tank, and avoiding the use of garbage disposal systems that introduce
additional solids and greases that can clog the system. Garbage
should be placed in the trash not down toilets or drains. This includes
chemicals, paints, oils, solvents, acids, pesticides, or excessive
cleaning solutions that destroy the beneficial bacteria in the tank,
decrease sludge production and pollute groundwater. Lastly, take
steps to conserve water, the less you use, the less that is entering
the system.
The most common problem with septic systems
is hydraulic failure. This means that the system can no longer purify
the wastewater. Indications of this are strong odors emanating near
the septic tank or soil absorption system. Sewage and effluent coming
out of the ground and ponding are another indication. Dead grass
in the septic area can be another clue. Finally, if sinks and toilets
do not drain properly, plumbing backs up, or gurgling sounds start
occurring in the plumbing, the system may be failing. If doubts
arise whether the system is operating properly, call a professional,
it is the home owner's responsibility to keep the system operating
properly and health departments have the ability to penalize owners
if their systems fail from neglect.
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