1. Introduction
The problem of wastewater pollution is one of
major problems in Thailand, particularly in domestic
wastewater. The domestic wastewater or sewage is
produced from community activities such as house
cleaning and cooking in restaurants. Houses and
restaurants generate sewage from washing activities
such as cleaning dishes and containers. Usually, the
sewage discharged into water body contains various
contaminants which could adversely affect the creature
in the water sources. Fat oil and grease (FOG) is one of
main contaminants and can accumulate and float on the
surface of water. It caused to block the oxygen
transference between air and water and to prevent the
biodegradation of organic matters. Moreover, FOG
normally clogs the piping system of maintenance
which is costly for concerning authority to solve the
problem [1]. Therefore, the Ministry of Natural
Resources and Environment, Thailand has emphasized
the installation of grease traps to reduce the impact of
FOG in wastewater before draining into public water
sources. However, it has been found that the grease
traps currently used in houses are not effectively
reducing FOG before releasing to the public water
sources [2]. Generally, the grease traps can dispose
about 60% of FOG [3]. Hence, it is significant to study
the factors that influence on the operational efficiency
in FOG removal for maximum treatment of domestic
wastewater and reduction of the impacts on water body
and is environmental friendly