Industrial firms that kill and process chickens generate wastewater that contains fat, oil, and grease
(FOG). The FOGs are located in the fatty waste that is collected by floatation in grease traps. Chemical
and physical characterisation of FOGs would provide useful information that would help in the development
of methods designed to decrease the extent of pollution caused by disposal of the waste and to utilise
commercially some of its lipid constituents. Employing these methods would enhance the
profitability and competitive potential of these commercial organisations. Samples of grease trap waste
from 14 firms in central Thailand have been examined. Due to the very different schemes of waste management
employed by these firms, the physical appearance of their fatty wastes showed considerable
variation. The chemical and physical properties of the FOGs present in these wastes showed considerable
variation also. Large amounts of free fatty acids (10–70% as oleic acid) were detected in most of the 14
wastes and palmitic, cis-9-oleic, cis,cis-9,12-linoleic, stearic, and palmitoleic acids were the predominant
species of free and esterified acids. Most of the FOGs were solid at temperatures below 40 C. Many of
them contained traces of heavy metals (Cu and Pb) and some contained traces of the pesticides dimethoate
and cypermethrin. The content of these potentially hazardous substances would have to be considered
very carefully before discarding the fatty wastes and during the development of methods designed
to isolate their potentially profitable lipid constituents.