The Effect of Organic Loading Rate on Milk WastewaterTreatment Using Sequencing Batch Reactor (SBR)

Document Type : Research Paper


1 M.Sc., Dept. of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran

2 Assist. Prof., Dept. of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran

3 Assist. Prof., Environmental Science Research Institute, Shahid Beheshti University, Tehran


In this study, four aerobic sequencing batch reactors (SBRs) were operated under the same conditions for the treatment of milk wastewater at different organic loading rates (OLRs). Cylindrical Plexiglas reactors were run for 56 days (including 21 days of acclimatization and 35 days of data gathering). Effective volume, influent wastewater flowrate, and sludge retention time (SRT) of reactors were 5.5 L, 3.5 L/d, and 10 d, respectively. The average COD removal efficiency for the reactors R1, R2, R3, and R4 with influent OLRave values of 633, 929, 1915, and 3261 gCOD/m3d were 95, 96, 95, and 82 percent, respectively. The average effluent suspended solid (SS) for all reactors was lower than 44 mg/L. Also, except for R4 with an average effluent turbidity of 270 NTU, other reactors met the Iranian wastewater emission standard (50 NTU). In addition, the average sludge volume index of reactors R1 to R3 was found to be lower than 67 mL/g. According to the results, the overall variation of COD removal efficiency versus influent OLR shows a decreasing rate with a correlation factor of 0.8 (R2).


1- گزارش آماری. (1386). مرکز اطلاعات صنعتی و تکنولوژیکی وزارت صنایع و معادن، تهران.
2- Healy, M.G., Rodgers M., and Mulqueen, J. (2007). “Treatment of dairy wastewater using constructed wetlands and intermittent sand filters.” J. Bioresource Technology, 98 (12), 2268-2281.
3- Broughton, A., Pratt, S., and Shilton, A. (2007). “Enhanced biological phosphorus removal for high-strength wastewater with a low rbCOD:P ratio.” J. Bioresource Technology, 99 (5), 1236-1241.
4- Arrojo, B., Mosquera-Corral, A., Garrido, J. M., and Mendez, R. (2004). “Aerobic granulation with industrial wastewater in sequencing batch reactors.” J. Water Research, 38 (14-15), 3389-3399.
5- Sirianuntapiboon, S., Jeeyachok, N., and Larplai, R. (2005). “Sequencing batch reactor biofilm system for treatment of milk industry wastewater.” J. Environmental Management, 76 (2), 177–183.
6- Garrido, J.M., Omil, F., Arrojo, B., Mendez, R., and Lema, J.M. (2001). “Carbon and nitrogen removal from a wastewater of an industrial dairy laboratory with a coupled anaerobic filter-sequencing batch reactor system.” J. Water Science and Technology, 43 (3), 249-256.
7- Ganesh, R., Balaji, G., and Ramanujam, R.A. (2006). “Biodegradation of tannery wastewater using sequencing batch reactor-respirometric assessment.” J. Bioresource Technology, 97 (15), 1815-1821.
8- Kargi, F., and Uygur, A. (2002). “Nutrient removal performance of a sequencing batch reactor as a function of the sludge age.” J. Enzyme and Microbial Technology, 31 (6), 842–847.
9- Bernet, D.P., Nicolas, D., Philipe, J., and Moletta, R. (2000). “Effects of oxygen supply methods on the performance of a sequencing batch reactor for high ammonia nitrification.” J. Water Environmental Research, 72 (2), 195-200.
10- Mohseni-Bandpi, A., and Bazari, H. (2004). “Biological treatment of dairy wastewater by sequencing batch reactor.” Iranian J. of Env. Health Sci. Eng., 1 (2), 65-69.
11- علوی مقدم، م.، گنجی دوست، ح.، و ترابیان، ع. (1377). تصفیه فاضلاب صنایع غذایی با استفاده از روش راکتور ناپیوسته با عملیات متوالی (SBR). مجله آب و فاضلاب، 28، 12- 21.
12- Ganjidoust, H., and Ayati, B. (2004). “Use of sequencing batch reactors (SBRs) in treatment of wood fiber wastewater.” Iranian J. of Env. Health Sci. Eng., 1 (2), 91-96.
13- APHA, AWWA, WEF. (1992). Standard methods for the examination of water and wastewater, 18th Ed.WashingtonDC.,USA.
14- سازمان محیط زیست. (1383). مجموعه قوانین و مقررات حفاظت محیط زیست ایران، جلد اول، تهران، 908-910.