Treatment of Synthetic Wastewater Containing Propylene Glycol by a Lab Scale Fixed Bed Activated Sludge Reactor

Document Type : Research Paper

Authors

1 Assoc. Prof. of Environmental Health Eng., Faculty of Public Health, Iran Uni. of Medical Sciences, Tehran

2 Assist. Prof.of Environmental Health Eng., Faculty of Public Health , Iran University of Medical Sciences, Tehran

3 Assist. Prof. of Environmental Health Eng., Faculty of Public Health, Tarbiat Modarres Uni., Tehran

4 Ph.D. Student of Environmental Eng., Faculty of Public Health, Tarbiat Modarres Uni., Tehran

Abstract

Propylene glycol is an organic compound which has wide applications in the pharmaceutical, cosmetics, chemical, and food processing industries. Propylene glycol is readily released into surface and ground waters and the neighboring soils via industrial wastewater effluents posing many health and environmental hazards. The main purpose of this study was to determine the efficiency of fixed bed activated sludge reactor for propylene glycol removal from synthetic wastewater. The lab scale reactor consisted of a cubic Plexiglas aeration tank with a total volume of 16 liters, 12 liters for aeration and 4 liters for settling. 25% of the aeration tank was filled with media as fixed bed for the biofilm to form. To evaluate the optimum efficiency of the reactor under variable organic loadings, the organic loading was increased in two consecutive stages: first by HRT depletion, and second by increasing COD concentration. The COD removal efficiencies obtained for hydraulic retention times of 8, 6, 4 and 2 hours and at an influent COD concentration of 500 mg/L were 95.86, 95.12, 93.96, and 79.08 %, respectively. In the fallowing stages and based on the results obtained from the first stage, a constant HRT of 6 hrs and COD concentrations of 1000, 1500, 2000 and 2500 mg/L were experimented. The removal efficiencies for the above concentrations were 95.95, 88.54, 75.95, and 35.69%, respectively. The results from this study indicate that the fixed bed activated sludge bioreactor satisfactorily capable of removing propylene glycol.
 

Keywords


1- Agnieszka, Z., Tomasz, G., Joanna, Z., Magdalena, F., Rafał, F., Tomasz, K., and Zenon, L. (2007). “Biodegradation of poly(propylene glycol)s under the conditions of the OECD screening test.” Chemosphere., 67(5), 928-933.
2- Charles, A., John, W., and Davis, J. (2002). “An examination of the physical properties, fate, ecotoxicity and potential environmental risks for a series of propylene glycol ethers.” Chemosphere, 49(1), 61-73.
3- Rozman, K. K., Jatinder, B., and Antonia, M. (2006). “NTP-CERHR expert panel report on the reproductive and developmental toxicity of propylene glycol.” Reproductive Toxicology., 77(6), 485-638.
4- Bielefeldt, A., Langasekare, T., Utech, M., and Lapolantr, R. (2002). “Biodegradation of propylene glycol and associated hydrodynamic effects in sand.” Water Research, 36(7), 1707-1714.
5- Jaesche, P., Totsche, U., and Knabner, I. (2006). “Transport and anaerobic biodegradation of propylene glycol in gravel-rich soil materials.” J. of Contaminant Hydrology, 85(3-4), 271-286.
6- Joanna, R., Agnieszka, Z., Tomasz, G., and Zenon, L. (2003). “Isolation of poly (propylene glycol)s from water for quantitative analysis by reversed phase liquid chromatography.” J. of Chromatography, 1021(1-2), 11-17.
7- Agnieszka, Z., Tomasz, G., Joanna, Z., Magdalena, F., Rafał, F., and Zenon, L. (2007). “Bio-oxidation of tripropylene glycol under aerobic conditions.” Biodegradation, 19(3), 365-373.
8- Yen-Hui, L. (2008). “Kinetics of nitrogen and carbon removal in a moving-fixed bed biofilm reactor.” Applied Mathematical Modeling, 32(11), 2360-2377.
9- Bajaj, M., Gallert, C., and Winter, J. (2008). “Biodegradation of high phenol containing synthetic wastewater by an aerobic fixed bed reactor.” Bioresource Technology, 99(17), 8376-8381.
10- Xin, Z., Yanming, W., and Zhengfang, Y. (2006). “Oil field wastewater treatment in biological aerated filter by immobilized microorganisms.” Process Biochemistry, 41(7), 1475-1483.
11- Cresson, R., Escudie, R., Steye,r J., Delgenes, J., and Bernet, N. (2008(.“Competition between planktonic and fixed microorganisms during the start-up of methanogenic biofilm reactors.” Water Research, 42(3), 792-800.
12- ملکی، م.، و برقعی، م. (1384). عملکرد سنگ پامیس به‌عنوان بستر ثابت بیوفیلم در راکتور بیوفیلمی هوازی.  مجله علمی پژوهشی آب و فاضلاب.، 56 ، 62-72.
13- دلنواز، آ.، آیتی، ب.، و گنجی دوست، ح. (1387). تصفیه فاضلاب حاوی آنیلین با استفاده از بیوفیلمی با بستر متحرک.مجله علمی پژوهشی آب و فاضلاب.، 68، 9-19.
14- Tchobanoglous, G., and Burton, F. (1991). Wastewater engineering treatment and reuse, 4th Ed., Metcalf and Eddy, McGraw-Hill Inc., Boston.
15- Gabriel, B. (2005). Wastewater microbiology, 3rd Ed., John Wiley and Sons Inc. Publication, Gainesvillle, Florida.
16- APHA. (2005). Standard methods for the examination of water and wastewater, 21th Ed., American Public Health Association, New York.
17- Hamoda, M., and  Al-Ghusain, I. (1998). “Analysis of organic removal rates in the aerated submerged fixed film process.” Water Sci. Technol., 38(8-9), 213-221.
18- Jianlong, W., Hancheng, S., and Yi, Q. (2000). “Wastewater treatment in a hybrid biological reactor (HBR): Effect of organic loading rates.” Process Biochem., 36(4), 297-303.