For those living in a home served by a septic system or if you are thinking about buying one, this information is for you. The Department has written a Homeowner's Manual and other guidance to help people understand the science and best management practices involved with onsite wastewater treatment technology.
For starters, New Jersey law requires people to conform to various statewide standards. These rules titled, “Standards for Individual Subsurface Sewage Disposal Systems,” ensure the effective removal of disease-causing pathogens and chemical nutrients from domestic wastewater. In addition to the law, NDEP has developed guidance and encourages all municipalities and septic owners to manage and maintain their septic systems to prevent system failures which may result in untreated wastewater being discharged into the environment.
Real Estate Sales and Onsite Wastewater Treatment Systems
When buying a property that is served by a septic system NJDEP recommends that all interested purchasers secure a septic system inspection to ward off any costly repairs or liabilities following a real estate transaction. New Jersey has established an inspection protocol, so it is encouraged to review the protocol before inspecting. This guidance titled, "Technical Guidance for Inspections of Onsite Wastewater Treatment and Disposal Systems" is a key document in the Onsite Wastewater Management Program. Inspections are important because they determerine that a system is currently functioning properly and can help to determine if the system will suit long term needs, such as future additions, plans for decks, swimming areas and other construction projects. Also people planning pre-purchase home construction and are unsure of their septic system location and its condition, should consider securing an inspection before proceeding, because heavy machinery and certain construction materials such as paint and solvents can inadvertently damage a septic system or alter its performance. Lastly, all homeowners thinking about buying a septic system should know that proper care begins setting up a maintenance schedule (such as with any home utility, like a furnace) and knowing what can and cannot be discharged into the system, which is then recharged into the groundwater.
If you have problems with downloading documentation, contact NJDEP's Bureau of Nonpoint Pollution Control and request to speak with someone from the Onsite Wastewater Management Program at (609) 633-7021.
How a Septic System Works?
the processes that treat wastewater are
complex, the way a conventional septic
systems works is really quite simple.
A typical septic system contains three major
effluent distribution system
a person flushes the toilet or empties a
bathtub or washing machine, the wastewater
follows the plumbing, usually by gravity,
to the septic tank. At the tank, the solids
settle out and the liquid stays long enough
to become fermented and to become enriched
with beneficial bacteria.
septic tank is usually made of concrete,
fiberglass, or plastic, is typically buried
and should be watertight. All septic tanks
have baffles (or tees) at the inlet and
outlet to insure proper flow patterns. Most
septic tanks are single compartment; however,
some people install two-compartment tanks
or two single compartment tanks in series.
While typically designed to hold a minimum
of 1000 or more gallons of sewage, the size
of the tank may vary depending upon the
number of bedrooms in the home and state
and local regulatory requirements. The primary
purpose of the septic tank is to separate
the solids from the liquids and to promote
partial break-down of contaminants by microorganisms
naturally present in the wastewater. The
solids, known as sludge, collect on the
bottom of the tank, while the scum floats
on the top of the liquid. The sludge and
scum remain in the tank and should be pumped
out periodically. Solids that are allowed
to pass from the septic tank may clog the
absorption field. Keeping solids out of
the absorption field not only prevents clogging,
but also reduces potentially expensive repair
or replacement costs and helps ensure the
ability of the soil to effectively treat
the septic tank effluent.
Image showing the basic diagram of inside a septic tank.
additional safeguard in keeping solids out
of the absorption field is the use of effluent
filters on the outlet of the septic tank.
The wastewater (effluent) coming out of
the septic tank may contain many potentially
disease-causing microorganisms and other
pollutants such as nitrates, phosphates,
the effluent leaves the septic tank, it
is transported either by gravity or by pumps
to the distribution box and laterals. The
distribution box is included as part of
the system to separate the septic tank effluent
evenly into a network of distribution lines
that make up the absorption field. The main
pipe from the septic tank leads to the distribution
box or "D-Box" from which an equal
amount of effluent is channeled to each
of the laterals. The laterals are located
underground and become part of the zone
of treatment and zone of disposal. The zone
of disposal is illustrated in the figure
below and works as follows. The effluent
is distributed through the perforated pipes,
exits through the holes in the pipes, and
trickles through the rock or gravel where
it is stored until absorbed by the soil.
The zone of treatment, which is located
in the unsaturated zone of the soil, treats
Image showing animation of basic disposal field cross-section.
wastewater through physical, chemical,
and biological processes. The soil also
acts as a natural buffer to filter out many
of the harmful bacteria, viruses, and excessive
nutrients, effectively treating the wastewater
as it passes through the unsaturated zone
before it reaches the groundwater. This
treatment primarily occurs at the top of
the zone of treatment, where a Biomat develops,
consisting of living beneficial bacteria,
organic matter, and mineral precipitates.
The Biomat provides a substrate for decomposition
of the "bad" bacteria. The "clean"
wastewater enters the ground water again
in the "Zone of Disposal", which
is typically permeable soil or rock material
that is above the water table. If the zone
of treatment has adequate oxygen, which
occurs when it is separated from the water
table by at least 2 to 4 feet, it effectively
converts ammonia nitrogen to nitrate nitrogen,
and it reduces the number of harmful bacteria
and viruses to levels that are safe for
humans. Even after treatment, wastewater
still contains nutrients, such as nitrates
and phosphates, that in excessive amounts
may pollute nearby waterways and groundwater
supplies. Excessive nutrients in drinking
water supplies can be harmful to human health
and can degrade lakes and streams by enhancing
weed growth and algal blooms. Some of the
nutrients are retained or become assimilated
by plants and microbes, but much of the
nitrate nitrogen and some of the phosphates
still discharge to the ground water, and
may enter streams and can cause or contribute
to the eutrophication. Therefore, though
generally safe for humans, the conventional
septic system is responsible for a certain
amount of water pollution even when the
system is working perfectly. Requiring distance
setbacks from streams and potable wells
provides the final level of protection.
With the setbacks in place, and as long
as the septic systems are not malfunctioning,
homeowners can be assured that both drinking
water and surface water are adequately protected.