Baseline "Basic" Septic Tank Operation
Basic Septic Tank Systems are a viable
alternative for waste water processing. Like any other device,
septic tanks must be properly installed, maintained, and repaired.
Literature verifies that the average life of a septic tank with
acidic water conditions, as we find in Charlotte County is between
25 to 30 years due to the action of Hydrogen Sulfide Gas on the
concrete surface.
Basic septic tanks systems consist of the tank, a distribution box,
and the drain field. Older tanks are one chambered, while newer ones
have two chambers. The waste water from the home enters the tank
through the inlet pipe. The waste water is allowed to settle, with a
desired retention time of at least two days. During this period the
heavier material settles to a layer called sludge, while the lighter
materials including oils and grease, form an upper layer called the
scum layer.
Anaerobic Bacteria (oxygen hating) work on the sludge breaking down
the material so that most of it will eventually wind up in solution
and be able to move out the outlet pipe into the distribution box
and then the drain field. The tank has to be properly sized
according to the occupant load and the computed resultant daily
flow. The proper sizing will allow the required retention time for
the biological processing.
The drain field is designed to gradually percolate the waste water
through the properly placed soil type that allows mineral and
bacterial processing prior to the effluent reaching the ground water
table. The drain field is sized to match the estimated daily flow
from the tank.
The build up of scum and sludge in the tank is dependent on the
daily flow and the composition of the waste. The five year
inspection and pump out program takes into account nation wide data
that was compiled by the Environmental Protection Agency, and
incorporated in technical transmissions to State Governments and the
publishing of the “ A Homeowner’s Guide to Septic Systems.
Home owners can help maintain their septic systems healthy by
ensuring that they never put any of the following items down any
drain leading to the septic tank:
- Disposable Diapers
- Chemicals such as photo chemicals, paints, thinners, oils,
varnishes, pesticides, used motor oil, cooking oils.
- Cigarette butts and Coffee Grounds.
- Any type of soil or dirt.
- Drugs and Medicines.
- Kitty Litter.
- Condoms, gloves paper towels, panty liners, sanitary napkins
and tampons.
- Trash and scraps.
- Water in large quantities can overload the system. Monitor
roof gutters and surface runoff.
- Hair and washing machine lint can also build up in the
system.
- Dish wash machines and clothes washers can also overload a
system if extra guests are visiting.
The periodic inspection and pump out of a septic tank can help
save the homeowner from expensive repairs to the drain field. That
program will also ensure that present and future generations have
clean usable potable and recreational waters.
What can go wrong?
 This
is an example of a complete failure. The drain field is not
accepting effluent with the resultant surface spill and backup into
the home.
Tank inspections are very important, as we
typically do not see what is happening under the ground on a daily
basis. Corrosion and the effects of Hydrogen Sulfide
gas can be seen below:
Corrosion inside a septic tank can be seen
after pumping it out.
Drain field failure evidenced by sewage on
the lawn.
Or
larger problems as can be found at apartment or business septic
failures.
Play the "What's wrong with this
picture?" Game
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