Investigation of thecontrol of the fat, oil and grease in sewer lines and their removal by surfactant treatment

Document Type : Research Paper


1 Department of Chemical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran

2 Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran

3 3 Water treatment and wastewater Treatment Research Group, Environmental Research Institute, University of Isfahan, Isfahan, Iran

4 Department of Environmental Engineering, University of Tehran, Tehran, Iran


This study investigated different methods of controlling the fat, oil and grease (FOG) in sewer systems. A comprehensive control program was developed for the city of Mashhad (Iran) to maintain its sewer system and prevent blockages. The control program consisted of three parts: 1) fat, oil and grease source control, 2) sewer system modification, and 3) preventive maintenance. This program included guidelines for food service establishments, which are the major sources of (FOG). Food service establishments must implement better management practices to reduce (FOG) from entering the facility drain and install grease removal devices. As a part of preventive cleaning, the performance of several surfactants was evaluated as a cleaning agent. A 50:50 mixture (10 v. % in water) of two industrial surfactants, one containing monoethyl amine and sulfonated lauryl alcohol and one containing nonylphenol ethoxylate and potassium hydroxide, had the best performance and removed 80 % of the fat. Response Surface Methodology was used to determine the optimum conditions for the surfactant. The optimum conditions were a contact time of 36 h, shaking rate of 30 rpm and surfactant concentration of 12.5%. The second part of the program consisted of removing dead zones and increasing wastewater velocity in the sewer lines to enhance the hydraulic condition of the sewer system and decrease fat deposition. Finally, a detailed and well-defined control program could solve FOG problems in sewer systems.


Main Subjects

[1] Kamali, M, Pirooz, M, Asadollahi, M. A., Tavakoli, S., Amin, M. M. (2016). Municipal sewer lines blockage due to fat, oil and grease depositions, confronting and prevention methods. Health System Research Journal, 12(4), 396-405. (In Persian)
[2] Arthur, S., Crow, H., Pedezert, L. (2008). Understanding blockage formation in combined sewer networks. In proceedings of the institution of civil Engineers-Water Management (Vol. 161, No. 4, pp. 215-221). Thomas Telford Ltd.
[3] Keener, K. M., Ducoste, J. J., Holt, L. M. (2008). Properties influencing fat, oil, and grease deposit formation. Water environment research, 80(12), 2241-2246.
[4] Husain, I. A., Alkhatib, M. A. F., Jammi, M. S., Mirghani, M. E., Zainudin, Z. B., Hoda, A. (2014). Problems, control, and treatment of fat, oil, and grease (FOG): a review. Journal of oleo science, ess13182.
[5] O’Dwyer, M., (2012). Dublin City Council Water Services Training Group Guidance document. Dublin City Council’s Experience – A case study.
[6] Scoble, C., Day, N. (2002). Grease Under Control at South East Water. In proceedings of the 65th annual water industry engineers and Operators’ Conference. Geelong, Australia, 4th–5th September.
[7] Water, S. (2012). Your guide to disposing cooking fats. SW SS, 4, 12.
[8] Kamali, M., Pirooz, M., Jalilian, J., Asadollahi, M. A. (2016). Physical and Chemical Characterization of the fat and oil deposits in Mashhad city sewer lines and proposing solutions to this problem. Water and Wastewater Journal, 27(6), 69-77. (In Persian)
[9] He, X., Francis III, L., Leming, M. L., Dean, L. O., Lappi, S. E., Ducoste, J. J. (2013). Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines. Water research, 47(13), 4451-4459.
[10] He, X., Osborne, J., de los Reyes, F. L. (2012). Physico-chemical characterization of grease interceptors with and without biological product addition. Water environment research, 84(3), 195-201.
[11] Marchetti, J. M., Miguel, V. U., Errazu, A. F. (2007). Heterogeneous esterification of oil with high amount of free fatty acids. Fuel, 86(5-6), 906-910.
[12] Williams, J. B., Clarkson, C., Mant, C., Drinkwater, A., May, E. (2012). Fat, oil and grease deposits in sewers: Characterisation of deposits and formation mechanisms. Water research, 46(19), 6319-6328.
[13] Institute of Standards and Industrial Research of Iran. (1996). Animal and vegetable fats and oils- analysis by gas chromatography of methyl esters of fatty acids. ISIRI number 4091. Tehran. (In Persian)
[14] The Plumbing and Drainage Institute. (2010). Testing and Rating Procedure for Hydro Mechanical Grease Interceptors with Appendix of Installation and Maintenance.

[15] The American society of mechanical engineers. (2018). Hydromechanical Grease interceptors A112.14.3. Available from:

[16] The American society of mechanical engineers. (2001). Grease removal Devices A112.14.4. Available from:
[17] Research Foresight Partnership. (2008). Design to minimise fog in new sewer design. Document number P7723_Chapter_4.
[18] Research Foresight Partnership. (2008). Retrofitting of existing sewer systems. Document number P7723_Chapter_3.
[19] Research Foresight Partnership. (2008). Retrofitting to minimise fog in existing pumping. Document number P7723_Chapter_5.
[20] Montgomery, D. C. (2017). Design and analysis of experiments. John wiley sons.