The investigation of biological removal of nitrogen and phosphorous from domestic wastewater by inserting anaerobic/anoxic holding tank in the return sludge line of MLE-OSA modified system

  • Behzad NikpourEmail author
  • R. Jalilzadeh Yengejeh
  • A. Takdastan
  • A. H. Hassani
  • M. A. Zazouli
Research article


In this study, the biological removal of nitrogen and phosphorous (BNR) was investigated by applying modified MLE-OSA technique. To conduct this study, three pilot plants scale were designed and established: 1) MLE similar to the current method used in Sari Wastewater Treatment Plant as control reactor 2) MLE-OSA4 with 4-h hydrolic retention time in sludge holding tank 3) MLE-OSA6 with 6-h hydrolic retention time in sludge holding tank. In this modified process for combining OSA technique with MLE system, two anaerobic/anoxic tanks were installed in the return sludge line with capacities of 70 and 107 l for MLE-OSA4 and MLE-OSA6, respectively. To set up the process, outlet sewage of the primary settlement tank of Sari Wastewater Treatment Plant was used. After a period of 45–60 days and reaching the steady state, the reactors were operated and the main, controllable parameters and laboratory experiments such as DO, ORP, Temperature, pH, COD, BOD5, MLSS, and nutrients (N&P) were precisely analyzed according to standard methods for examination of water and wastewater. The results showed that utilizing MLE-OSA system with 4 and 6 h hydraulic retention times decreased the ORP by around 109 ± 9 to 160 ± 25 mv and increased sludge retention time from 29 to 33 days. Moreover the percentages of phosphorus removal efficiency in MLE, MLE-OSA4 and MLE-OSA6 processes were 31 ± 5.2, 36.8 ± 1.9, and 39.4 ± 1.9 and the percentages of total nitrogen removal efficiency were 67.2 ± 7.6, 75.6 ± 4.8, and 78.5 ± 2.2 respectively. This study revealed that the modified MLE-OSA is more efficient than MLE for P and N removal. Hence it can replace this process.


Domestic wastewater MLE-OSA Sludge holding tank Nitrogen Phosphorous Biological nutrient removal 



This article is extracted from the Ph.D thesis and belongs to the Ahvaz Branch Islamic Azad University. It is also a part of the research project No 7337/150. The authors would like to aknowledge Mazandaran Water & Wastewater Co, Health Science Research Center of Mazandaran University of Medical Sciences, Mr. Ehsan Mehdizadeh, the responsible operator of the Sari Sewage Treatment Plant and his colleagues, the officials and staff of Sari Sewage Treatment Plant. Finally we appreciate the lab chief for his support of this project.

Compliance with ethical standards

Conflict of interest

The author declare that they have no conflict of interest.


  1. 1.
    Zazouli MA, Safarpour M, Dobaradaran S, Veisi F. Modeling of nitrate removal from aqueous solution by fe-doped TiO2 under UV and solar irradiation using response surface methodology. Global Nest J. 2015;17(2):379–88.CrossRefGoogle Scholar
  2. 2.
    Mohseni-Bandpi A, Elliott DJ, Zazouli MA. Biological nitrate removal processes from drinking water supply-a review. J Environ Health Sci Eng. 2013;11(1):35.CrossRefGoogle Scholar
  3. 3.
    Zazouli MA, Dianatitilaki R, Safarpour M. Nitrate removal from water by Nano zero Valent Iron in the presence and absence of ultraviolet light. Journal of Mazandaran University of Medical Sciences. 2014;24(113):151–61.Google Scholar
  4. 4.
    Naghizadeh A, Mahvi A, Vaezi F, Naddafi K. Evaluation of hollow fiber membrane bioreactor efficiency for municipal wastewater treatment. J Environ Health Sci Eng. 2008;5(4):257–68.Google Scholar
  5. 5.
    Naghizadeh A, Mahvi AH, Mesdaghinia AR, Alimohammadi M. Application of MBR technology in municipal wastewater treatment. Arab J Sci Eng. 2011;36(1):3–10.CrossRefGoogle Scholar
  6. 6.
    Metcalf W. Metcalf and Eddy wastewater engineering: treatment and reuse. In: Wastewater engineering: treatment and reuse. New York: McGraw Hill; 2003.Google Scholar
  7. 7.
    Wang J, Zhao Q, Jin W, Lin J. Mechanism on minimization of excess sludge in oxic-settling-anaerobic (OSA) process. Front Environ Sci Eng China. 2008;2(1):36–43.CrossRefGoogle Scholar
  8. 8.
    Khursheed A, Sharma MK, Tyagi VK, Khan AA, Kazmi AA. Specific oxygen uptake rate gradient–another possible cause of excess sludge reduction in oxic-settling-anaerobic (OSA) process. Chem Eng J. 2015;281:613–22.CrossRefGoogle Scholar
  9. 9.
    Chudoba P, Morel A, Capdeville B. The case of both energetic uncoupling and metabolic selection of microorganisms in the OSA activated sludge system. Environ Technol. 1992;13(8):761–70.CrossRefGoogle Scholar
  10. 10.
    Chudoba P, Chudoba J, Capdeville B. The aspect of energetic uncoupling of microbial growth in the activated sludge process-OSA system. Water Sci Technol. 1992;26(9–11):2477–80.CrossRefGoogle Scholar
  11. 11.
    Demir Ö, Filibeli A. The investigation of the sludge reduction efficiency and mechanisms in oxic–settling–anaerobic (OSA) process. Water Sci Technol. 2016;73(10):2311–23.CrossRefGoogle Scholar
  12. 12.
    Novak JT, Chon DH, Curtis BA, Doyle M. Biological solids reduction using the cannibal process. Water Environ Res. 2007;79(12):2380–6.CrossRefGoogle Scholar
  13. 13.
    Vitanza R, Diociaiuti T, De Arana-Sarabia ME, Colussi I, Cortesi A, Gallo V. Preliminary evaluation of sludge minimization by a lab-scale OSA (Oxic-Settling-Anaerobic) system. Chem Eng Trans. 2016;49:469–74.Google Scholar
  14. 14.
    Takdastan A, Karimi F, Orooji N. Effect of Oxic-settling anoxic process on operation parameters and biological excess sludge reduction in sequencing batch reactor activated sludge. Journal of Mazandaran University of Medical Sciences. 2018;28(162):128–40.Google Scholar
  15. 15.
    Takdastan A, Eslami A. Application of energy spilling mechanism by para-nitrophenol in biological excess sludge reduction in batch-activated sludge reactor. Int J Energy Environ Eng. 2013;4(1):26.CrossRefGoogle Scholar
  16. 16.
    Takdastan A, Mehrdadi N, Azimi A, Torabian A, Bidhendi G. Investigation of intermittent chlorination system in biological excess sludge reduction by sequencing batch reactors. J Environ Health Sci Eng. 2009;6(1):53–60.Google Scholar
  17. 17.
    Takdastan A, Azimi AA, Jaafarzadeh N. Biological excess sludge reduction in municipal wastewater treatment by chlorine. Asian J Chem. 2010;22(3):1665.Google Scholar
  18. 18.
    Fazelipour M, Takdastan A, Jou MS. Survey on chlorine application in sequencing batch reactor waste sludge in order to sludge minimization. Asian J Chem. 2011;23(7):2994.Google Scholar
  19. 19.
    Takdastan A, Mehrdadi N, Torabian A, Azimi AA, Bidhendi GN. Investigation of excess biological sludge reduction in sequencing bach reactor. Asian J Chem. 2009;21(3):2419–27.Google Scholar
  20. 20.
    Takdastan A, Pazoki M. Study of biological excess sludge reduction in sequencing batch reactor by heating the reactor. Asian J Chem. 2011;23(1):29–33.Google Scholar
  21. 21.
    Pazoki M, Takdastan A, Jaafarzadeh N. Investigation of minimization of excess sludge production in sequencing batch reactor by heating some sludge. Asian J Chem. 2010;22(3):1751–9.Google Scholar
  22. 22.
    Bortoli M, Kunz A, Prá MC, Silva ML, Cé A, Soares HM. Simultaneous removal of nitrogen and organic carbon from swine wastewater using the pre-denitrification/nitrification process. Rev Ambient Água. 2019;14(2).CrossRefGoogle Scholar
  23. 23.
    Wałęga A, Chmielowski K, Młyński D. Nitrogen and phosphorus removal from sewage in biofilter–activated sludge combined systems. Pol J Environ Stud. 2019;28:1939–47.CrossRefGoogle Scholar
  24. 24.
    Federation WE, American Public Health Association. Standard methods for the examination of water and wastewater. Washington, DC. edition: American Public Health Association (APHA); 2014.Google Scholar
  25. 25.
    Bitton G. Wastewater microbiology. Hoboken: Wiley; 2005.CrossRefGoogle Scholar
  26. 26.
    Ye FX, Zhu RF, Li Y. Effect of sludge retention time in sludge holding tank on excess sludge production in the oxic-settling-anoxic (OSA) activated sludge process. Journal of Chemical Technology & Biotechnology: International Research in Process, Environmental & Clean Technology. 2008;83(1):109–14.CrossRefGoogle Scholar
  27. 27.
    Troiani C, Eusebi AL, Battistoni P. Excess sludge reduction by biological way: from experimental experience to a real full scale application. Bioresour Technol. 2011;102(22):10352–8.CrossRefGoogle Scholar
  28. 28.
    Saby S, Djafer M, Chen GH. Effect of low ORP in anoxic sludge zone on excess sludge production in oxic-settling-anoxic activated sludge process. Water Res. 2003;37(1):11–20.CrossRefGoogle Scholar
  29. 29.
    Datta T, Liu Y, Goel R. Evaluation of simultaneous nutrient removal and sludge reduction using laboratory scale sequencing batch reactors. Chemosphere. 2009;76(5):697–705.CrossRefGoogle Scholar
  30. 30.
    Goel RK, Noguera DR. Evaluation of sludge yield and phosphorus removal in a cannibal solids reduction process. J Environ Eng. 2006;132(10):1331–7.CrossRefGoogle Scholar
  31. 31.
    Zhou Z, Qiao W, Xing C, Wang C, Jiang LM, Gu Y, et al. Characterization of dissolved organic matter in the anoxic–oxic-settling-anaerobic sludge reduction process. Chem Eng J. 2015;259:357–63.CrossRefGoogle Scholar
  32. 32.
    Zhou Z, Qiao W, Xing C, An Y, Shen X, Ren W, et al. Microbial community structure of anoxic–oxic-settling-anaerobic sludge reduction process revealed by 454-pyrosequencing. Chem Eng J. 2015;266:249–57.CrossRefGoogle Scholar
  33. 33.
    Salem S, Moussa MS, Van Loosdrecht MC. Determination of the decay rate of nitrifying bacteria. Biotechnol Bioeng. 2006;94(2):252–62.CrossRefGoogle Scholar
  34. 34.
    Chen GH, An KJ, Saby S, Brois E, Djafer M. Possible cause of excess sludge reduction in an oxic-settling-anaerobic activated sludge process (OSA process). Water Res. 2003;37(16):3855–66.CrossRefGoogle Scholar
  35. 35.
    Li X, Liu X, Wu S, Rasool A, Zuo J, Li C, et al. Microbial diversity and community distribution in different functional zones of continuous aerobic–anaerobic coupled process for sludge in situ reduction. Chem Eng J. 2014;257:74–81.CrossRefGoogle Scholar
  36. 36.
    Ferrentino R, Langone M, Merzari F, Tramonte L, Andreottola G. A review of anaerobic side-stream reactor for excess sludge reduction: configurations, mechanisms, and efficiency. Crit Rev Environ Sci Technol. 2016;46(4):382–405.CrossRefGoogle Scholar

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© Springer Nature Switzerland AG 2020

Authors and Affiliations

  1. 1.Department of Environmental Engineering, Khuzestan Science and Research Branch, Islamic Azad University, Ahvaz, Iran and Department of Environmental Engineering, Ahvaz BranchIslamic Azad UniversityAhvazIran
  2. 2.Department of Environmental Engineering, Ahvaz BranchIslamic Azad UniversityAhvazIran
  3. 3.Department of Environmental technologies research centerAhvaz Jundishapur University of medical sciencesAhvazIran
  4. 4.Faculty of Natural resources and Environment, Department of Environmental Engineering, Science and Research BranchIslamic Azad UniversityTehranIran
  5. 5.Department of Environmental Health, Health Sciences Research Center, Faculty of HealthMazandaran University of Medical SciencesSariIran

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