The most common way to dispose of
wastewater in rural homes is through the use of a septic tank. About
95% of the onsite disposal systems in the U.S. are septic tank
systems.
A septic tank system contains two
major components: a septic tank and the absorption field. The septic
tank is usually made of concrete, fiberglass, or plastic and is buried
and watertight. All septic tanks should have baffles (internal slabs
or tees) at the inlet and outlet to insure proper flow patterns. Most
septic tanks are single compartment, but a number of state require
multi-compartment tanks or two tanks in a series. While typically
designed to hold 1,000 gallons of liquid, the size of the tank varies
depending upon the number of bedrooms in the home and state and local
requirements. The primary purpose of the septic tank is to separate
the solids from the liquids and to promote partial breakdown of
contaminants by bacteria. The solids, in the form of sludge that
collects on the bottom of the tank, and scum, which floats on the top
of the water, remain in the tank and are pumped out periodically
(septic tank maintenance).
The wastewater is passed on to the
absorption field through a connecting pipe. The absorption field is
also known as the soil drainfield, the disposal field, or the
leachfield. The absorption field contains a series of underground
perforated pipes that are commonly, but not always, connected in a
closed loop system.
The wastewater is distributed to the
entire absorption field through the perforated pipes. The absorption
field which is located in the unsaturated zone of the soil, treats the
wastewater through an aerobic (oxygenated) digestion process and
removes the remaining impurities (germs and chemicals) before the
wastewater returns to the groundwater.
The wastewater (effluent) coming out
of the septic tank is a cloudy liquid that still contains many
disease-causing germs and pollutants. When this water flows into the
perforated pipe in the absorption field, the effluent exits through
the holes in the pipe and trickles through the rock or gravel where it
is stored until it is absorbed by the soil. In some systems,
subsurface chambers store the effluent. As the effluent enters and
flows through the unsaturated soil, many of the bacteria that can
cause disease are filtered out. Some of the other smaller germs, such
as viruses, are trapped and held by the soil molecules (absorbed)
until they die. The soil can also retain certain nutrients such as
phosphorus and some forms of nitrogen.
What To Put In, What To Keep Out
• Put all wastewater from your home into the septic tank. This
includes all sink, bath, shower, washing machine and dishwasher
wastewaters, and toilet flushings. Any of these waters can contain
disease-causing germs or environmental pollutants.
• Keep roof drains, basement sump pump drains, and other rain
water or surface water drainage systems away from the absorption
field. Flooding of the absorption field with excessive water will keep
the soil from naturally cleansing the wastewater, leading to
groundwater pollution.
• Do not use caustic drain openers for a clogged drain. Instead
use boiling water or a drain snake to open clogs.
• Use potentially system-damaging commercial bathroom cleansers
in moderation. Many people prefer to clean their toilets, sinks,
showers and tubs with a mild detergent or baking soda.
• Check your local regulatory agency if you have a garbage
disposal to make sure that your septic system can accommodate this
additional use.
•NEVER use your septic tank system as a trash can. Do not put
grease, disposable diapers, plastics, latex paint, pesticides,
solvents, oven cleaners, degreasers, or any hazardous chemicals into
your system.
Summary
In summary, do not dispose of items
that will destroy the natural digestion process of your septic tank,
or overtax the drain field with excessive water. Have your septic tank
inspected regularly (every two to three years) and pump out the sludge
as necessary for good septic tank maintenance. If you adhere to these few simple rules, your septic
tank system will prove to be a safe and economical onsite method for
disposing of your rural home wastewater.
All Information In This Section Was Taken Directly From:
Title: So…Now you own a septic tank
Published By National Small Flows Clearing House
West Virginia University
P.O. Box 6064
Morgantown, West Virginia 26506-6064
800-624-8301
*National Small Flows Clearing House Is Not Affiliated With Winston
Company, Inc.
