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Wastewater fats oils and grease characterisation, removal and uses. A Review

Mpho Sello *

Municipal wastewater contains a variety of organic and inorganic substances from domestic and industrial sources. The presence of fats, oils and grease (FOG) in municipal wastewater has proven to have adverse effects on the wastewater treatment plants and aquatic life in which it is sometimes discharged. There are different technologies used for the removal of FOG in municipal wastewater treatment all over the world. These technologies differ in the percentage removal of FOG hence an accurate method for determining the oil content of a wastewater is extremely important. A number of tests can be used for the determination of FOG, but most tests involve extraction of the oil from water with a preferential solvent. Some of those solvents can be hexane, petroleum ether, benzene, ethyl ether, chloroform, n-hexane and carbon tetrachloride. After FOG is found in wastewater effluents, it may be recovered and reused, nevertheless reduction or prevention of pollution at the source is a key element in any pollution control strategy. However, after FOG is found in the effluent, pre-treatment measures as well as control of FOG at the source may be introduced in wastewater treatment and the recovered FOG can be reused. A number of options for the use of recovered FOG include land fill, land application, composting, provision for manufacturing lubricants or industry soaps, incineration, anaerobic codigestion, or biodiesel production.