Fat, Oil and Grease
In this section we thought it important to discuss items
that are detrimental to septic systems. We would like to
talk a little about Fats, Oils, and Grease (FOG) specifically.
This information comes from a report by Jorean Washington,
From the winter 2006 issue of the Florida Journal of Environmental
Fats, Oils, and Grease (FOG) remain an ongoing and current
issue of concern with
septic tank users. FOG increases the Biochemical Oxygen
Demands (BOD’s) and Total Suspended Solids (TSS’s)
in the wastewater stream. There are definite environmental
and economical impacts that should be considered.
In 1983 the US Environmental Protection Agency (EPA) mandated
that sewer use ordinances be put in place. The purpose was
to minimize the introduction of fat soluble wastes, including
petroleum-based hydrocarbons, into wastewater treatment
Since public wastewater treatment centers were mandated
to comply, maybe it is
important that you as an owner of a septic system also consider
what they have to say about FOG’s.
Some of the sources of FOG include:
Meat fats including beef, chicken, and pork
Butter and margarine
Cooking oil, and salad oil
Food scrapes put down garbage disposals
Sauces and gravy
Salad dressing, and mayonnaise
Dairy products milk, yogurt, and ice cream.
What is the effect of (FOG)
in drain fields?
The most serious problem that plagues these systems is the
carry-over of the
fats, oils, and grease into the chambers, piping, and sand.
This is usually the result of poor design and improper
maintenance. When carry- over occurs, these materials tend
to cling to the interior of piping or infiltrative surface.
(Biomat) of a drainfield or alternative treatment system
(e.g., infiltrator, corrugated pipe or sand filter), This
reduces the capacity of the system, and forms scum where
the liquid cannot penetrate.
FOG’s are particularly dangerous or destructive because
they are slow to Biodegrade especially in septic tank systems.
This is because the enzymes that breaks FOG down are less
active in lower temperatures that are found in septic tanks
and drainfield soil. Hence FOG tends to simply accumulate
in the soil.
The drainfield of a well-designed and maintained system
can handle small amounts of FOG, such as natural body oils
carried over from shower water.
However, many alternative treatment systems cannot accommodate
significant concentrations of FOG.
Cooking oil and grease should never be poured down the
drain. Also commercially available additives that claim
to reduce oils and grease should not be used. Their use
only increases the likelihood that these materials will
be carried over to the drainfield or discharge piping.
Carry-over oils and grease as noted above, clog the Biomat
and/or the piping, thus
decreasing absorption capabilities of drainfields. This
will lead to failure of the system.
The presence and use of harsh cleaners and other chemicals
potentially will harm
the bacteria that breaks down the matter in the septic tank.
Regular schedule pumping of the septic tank is one of the
most essential elements of system maintenance.
The final word: Avoid putting Fats, Oils, and Grease into
your septic system.