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Septic System
How Septic Systems
Operate...
Households not served by public sewers in New Jersey usually depend on a septic system to dispose of
wastewater. There are many different types of septic systems designed to fit a wide range
of soil and site conditions. These include mound systems, sand filter systems and pressure
distribution systems. This guide should help you understand the operation and maintenance
of a conventional gravity-flow septic system.
A conventional septic system in New Jersey consists of two main parts: the septic tank and the soil
drainfield (also referred to as a leachfield, absorption bed or absorption field). At the
head of the drainfield a distribution box or a manifold distributes wastewater to several
absorption trenches. Some locations require that newly installed drainfields include a
designated replacement area should the existing septic system need an addition, repair or
replacement, the replacement area can then be used.
The septic tank. A septic tank is a large,
underground, watertight container, typically about 9 feet long, 4-5 feet wide
and 5 feet tall that is connected to the home's sewer line. While typically
designed with a 1,000-gallon liquid capacity, the size of the tank is determined
by the number of bedrooms in the home. Septic tanks may be rectangular or
cylindrical and may be made of concrete, fiberglass, polyethylene or steel.
Steel tanks are no longer used and should be replace when found.
Raw waste water from the bathroom, kitchen and laundry room flows into the tank where
the solids separate from the liquid. Light solids, such as soap suds and fat, float to the
top and form a scum layer. This layer remains on top and gradually thickens until you have
the tank cleaned. The liquid waste goes into the drainfield, while the heavier solids
settle to the bottom of the tank where they are gradually decomposed by bacteria. But some
non-decomposed solids remain, forming a sludge layer that eventually must be pumped out.
Septic tanks may have one or two compartments. Two-compartment tanks do a better job of
settling solids and are required in some areas for new installations. Tees or baffles at
the tank's inlet pipe slow the incoming wastes and reduce disturbance of the settled
sludge. A tee or baffle at the outlet keeps the solids or scum in the tank. All tanks
should have accessible covers for checking the condition of the baffles and for pumping
both compartments
.
The Drainfield. Further treatment of wastewater occurs in the soil beneath the
drainfield. The drainfield consists of long underground perforated pipes or tiles
connected to the septic tank. The network of pipes is laid in gravel-filled trenches (2-3
feet wide), or beds (over 3 feet wide) in the soil. Liquid waste or effluent flows out of
the tank and is evenly distributed into the soil through the piping system. The soil below
the drain-field provides the final treatment and disposal of the septic tank effluent.
After the effluent has passed into the soil, most of it percolates downward and outward,
eventually entering the groundwater. A small percentage is taken up by plants through
their roots, or evaporates from the soil.
The soil filters the effluent as it passes through the pore spaces. Chemical and
biological processes treat the effluent before it reaches groundwater, or a restrictive
layer, such as hardpan, bedrock, or clay soils. These processes work best where the soil
is somewhat dry and permeable, and contains plenty of oxygen for several feet below the
drain field. The size and type of drainfield depends on the estimated daily wastewater
flow and soil conditions.
What is septic system failure?
A septic system should effectively accept liquid wastes from your house and prevent
biological and nutrient contaminants from getting into your well or nearby lakes and
streams. Anytime these things do not happen, the system is failing.
For example, when waste backs up in your backyard, the system has obviously failed. If
significant amounts of biological or nutrient contaminants reach your well or surface
waters, the system is also failing, even though it may appear to be working just fine.
Why septic systems fail?
Most septic systems in New Jersey are designed to have a lifetime of 20 to 30 years, under the best
conditions. However, many septic systems will fail before this time. Eventually, the soil
around the absorption field becomes clogged with organic material, making the system
unusable.
Many other factors can cause the system to fail well before the end of its
"design" lifetime. Pipes blocked by roots, soils saturated by storm water,
crushed tile, improper location, poor original design or poor installation can all lead to
major problems. Many systems (15 to 20 years) in Hunterdon County, Somerset
County and Mercer County need repairs or have had repairs due to some of the
factors listed above.
But by far the most common reason for early failure in New Jersey is improper maintenance by
homeowners. When a system is poorly maintained and not pumped out on a regular basis,
sludge (solid material) builds up inside the septic tank, then flows into the absorption
field, clogging it beyond repair.
If the New Jersey home you have an interest in has a septic
system, no mater the age, don't take any chances. Have it evaluated and be
Absolute'ly sure it's
working and safe.
Home Inspector NJ, House Inspection NJ, New Jersey Home
Inspector, New Jersey Home Inspection, NJ Home Inspector, NJ Home Inspection,
Home Inspector NJ, Septic Inspection NJ, Septic Inspector NJ
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