FOG Management
Oil &
Grease are vital components in commercial kitchen operations. According to a
research, the US restaurants produce about 25 billion gallons of used cooking
oil every week. There are no official figures about the same in India, but with
the size of the food services market estimated at $ 48 billion in 2013, it can
be safely said that the total edible oil consumption by commercial
establishments is growing and it directly reflects on the extent of fatty oil
and grease released in waste-water.
Common waste-water contains trace amount of
Fats, Oils and Grease collectively known as FOG which enter the drainage
system, with minuscule quantities getting broken down naturally in the sewer
system. But if huge quantities of FOG, usually from commercial or restaurant
kitchens enter untreated into the sewerage, it causes damage to the
environment. Small quantities of FOG float on the surface of the sewerage
before being broken down, but large quantities are viscous in nature. It
usually solidifies on cooling and coagulates with other solid waste in the
sewer to accumulate on the lining of the pipe.
Why it is
important to keep FOG of the sewers
Accumulation of FOG over a period of time causes
blockages of sewer pipelines. These blockages interface with the sewer flow and
lead to overflowing manholes and storm water drains. Cleaning up clogged sewers
is expensive! FOG accumulation only makes the task harder. And the sewage
system is not the only victim of improper management of FOG. The FOG lining can
wreak havoc with the drainage system of establishments. The blockages in the
sewer lines can cause back flows damaging the property and requiring additional
costs for the clean-up efforts. The blockages give out foul odor and attract
pest and rodents and become breeding grounds for various disease causing
organisms. This endangers the safety standards of the establishment. Since FOG
is essentially just solidified fat, it constitutes as hazardous waste. It is a
huge fire risk and is also damaging to the environment.
How to
manage FOG
Concrete steps have to be taken for FOG management.
Putting hot water down the drain along with the grease does not help. Grease
Traps of Grease interceptors are one of the most popular options in managing
FOG. A grease trap, intercepts the FOG and other solid matter from the waste-water in the drainage system before it reaches the sewers. They work on
the principle of oil being lighter than water. When kitchen waste-water flows
through a grease trap, the grease and oil rise to the surface and are trapped
inside the receptacle. It comes in three varieties – small passive grease
traps, large pre-cast concrete grease traps, and automatic grease / oils
removal systems.
The first two variants are essentially containers
that are connected to the plumbing system of the establishment that strain the waste-water for FOG and other solid wastes. Maintenance of these kinds of grease
traps are done manually that requires to empty the traps of the collected waste
oil. These traps lose their capacity to effectively remove grease from waste-water if filled beyond a point, so constant attention has to be paid to
ensure that the trap remains fairly empty.
The automatic grease/oil removal systems, skin out
the waste fat automatically based on a sensor or a timer mechanism. The
automatic grease removal process takes place daily in the case of timer-based
systems and before the trap is 10% full is a sensor-based system. Grease traps
are ideal as a starting point for FOG management.
How to
prevent FOG flow into sewers
Instead of managing FOG, efforts have to be made to
reduce their flow into the drainage system. Proper training of personnel can
ensure that there is minimum amount of FOG to be handled. Instruction on the
importance of keeping fats, oil, grease and food waste out of the drainage
system should be explained to the personnel. Failure to do the same can lead to
expensive clean-up operations to unblock the drain.
