Finding Chemical Pathways Toward the Valorization of Automobile-Service-Station Wastes


Automobile-service-station wastes make for an acute environmental concern because they contain polyaromatic hydrocarbons, heavy metals, surfactants, and other harmful elements. An eco-friendly way to treat and take advantage of these wastes is embodied in the concept called "valorization". In the present work, valorization is described as a chemical process to remove solids from contaminated water and to stabilize oily sludge into a saponified product. Electrocoagulation and coagulation with aluminum were applied to separate oil-water emulsions and removed 99.7% of turbidity. Both coagulation processes obtained approximately 0.85 kg of treated water and 0.027 kg of dried oily sludge per kg of wastewater. A saponification process with dosages of 10% NaOH stabilized the dried oily sludge. In hopes of finding pathways to valorize wastes, chemical treatments with aluminum and NaOH obtained a product that can be used as a surfactant or as an energy source.

Keywords: sludge, electrocoagulation, saponification, oil, wastewater 

[1] Adhoum, N., Monser, L., Bellakhal, N., & Belgaied, J. (2004). Treatment of electroplating wastewater containing Cu2+, Zn2+ and Cr(VI) by electrocoagulation. Journal of Hazardous Materials, 112(3), 207–213.

[2] Annunciado, T. R., Sydenstricker, T. H. D., & Amico, S. C. (2005). Experimental investigation of various vegetable fibers as sorbent materials for oil spills. Marine Pollution Bulletin, 50(11), 1340–1346.

[3] Banchon, C., Castillo, A., & Posligua, P. (2017). Chemical interactions to cleanup highly polluted automobile service station wastewater by bio-adsorption coagulation-flocculation. Journal of Ecological Engineering, 18(1), 1–10.

[4] Cañizares, P., Jiménez, C., Martínez, F., Sáez, C., & Rodrigo, M. A. (2007). Study of the Electrocoagulation Process Using Aluminum and Iron Electrodes. Industrial & Engineering Chemistry Research, 46(19), 6189–6195.

[5] Chawaloesphosiya, N., Mongkolnauwarat, J., Prommajun, C., Wongwailikhit, K., & Painmanakul, P. (2015). Treatment of cutting-oily wastewater by electrocoagulation-flotation (ECF) process: Modeling approach. Environmental Engineering Research, 20(4), 392–396.

[6] Hanafy, M., & Nabih, H. I. (2007). Treatment of Oily Wastewater Using Dissolved Air Flotation Technique. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 29(2), 143–159.

[7] IEA. (2017). World oil demand (International Energy Agency - Oil market report 2017 - Web service). Retrieved from

[8] Kabdaşlı, I., Arslan-Alaton, I., Ölmez-Hancı, T., & Tünay, O. (2012). Electrocoagulation applications for industrial wastewaters: a critical review. Environmental Technology Reviews, 1(1), 2–45.

[9] Madanhire, I., & Mbohwa, C. (2016). Lubricant Additive Impacts on Human Health and the Environment. In I. Madanhire & C. Mbohwa, Mitigating Environmental Impact of Petroleum Lubricants (pp. 17–34). Cham: Springer International Publishing.

[10] Mang, T. (Ed.). (2007). Lubricants and lubrication (2., completely rev. and extended ed). Weinheim: Wiley-VCH.

[11] Mouedhen, G., Feki, M., Wery, M. D. P., & Ayedi, H. F. (2008). Behavior of aluminum electrodes in electrocoagulation process. Journal of Hazardous Materials, 150(1), 124–135.

[12] Peng, G., & Tian, G. (2010). Using electrode electrolytes to enhance electrokinetic removal of heavy metals from electroplating sludge. Chemical Engineering Journal, 165(2), 388–394.

[13] Sabir, S. (2015). Approach of Cost-Effective Adsorbents for Oil Removal from Oily Water. Critical Reviews in Environmental Science and Technology, 45(17), 1916–1945.

[14] Vanhanen, J., Rinkiö, M., Aumanen, J., Korppi-Tommola, J., Kolehmainen, E., Kerkkänen, T., & Törmä, P. (2004). Characterization of used mineral oil condition by spectroscopic techniques. Applied Optics, 43(24), 4718–4722.

[15] Yeber, M., Paul, E., & Soto, C. (2012). Chemical and biological treatments to clean oily wastewater: optimization of the photocatalytic process using experimental design. Desalination and Water Treatment, 47(1–3), 295–299.

[16] Yu, L., Han, M., & He, F. (2013). A review of treating oily wastewater. Arabian Journal of Chemistry.