References
   -  G.H. Chen, G.A. Ekama, M.C.M. van Loosdrecht, D. Brdjanovic,
    Eds., Biological Wastewater Treatment: Principles, Modeling
    and Design, IWA Publishing, Printed by: Cambridge University
    Press, 12 Caxton Street, London SW1H 0QS, UK, 2020. 
 
  -  Y. Zhu, Y. Zhang, H.-Q. Ren, J.-J. Geng, K. Xu, H. Huang,
    L.-L. Ding, Physicochemical characteristics and microbial
    community evolution of biofilms during the start-up period in
    a moving bed biofilm reactor, Bioresour. Technol., 180 (2015)
    345–351. 
 
  -  L. Dvorák, T. Lederer, V. Jirků, J. Masák, L. Novák, Removal
    of aniline, cyanides and diphenylguanidine from industrial
    wastewater using a full-scale moving bed biofilm reactor,
    Process Biochem., 49 (2014) 102–109. 
 
  -  Y. Rahimi, A. Torabian, N. Mehrdadi, M. Habibi-Rezaie,
    H. Pezeshk, G.-R. Nabi-Bidhendi, Optimizing aeration rates
    for minimizing membrane fouling and its effect on sludge
    characteristics in a moving bed membrane bioreactor, J. Hazard.
    Mater., 186 (2011) 1097–1102. 
 
  -  W. Guo, H.-H. Ngo, F. Dharmawan, C.G. Palmer, Roles
    of polyurethane foam in aerobic moving and fixed bed
    bioreactors, Bioresour. Technol., 101 (2010) 1435–1439. 
 
  -  Y. Luo, Q. Jiang, H.H. Ngo, L.D. Nghiem, F.I. Hai, E.W. Price,
    J. Wang, W. Guo, Evaluation of micropollutant removal and
    fouling reduction in a hybrid moving bed biofilm reactor–membrane bioreactor system, Bioresour. Technol., 191 (2015)
    355–359. 
 
  -  Y. Shao, Y. Shi, A. Mohammed, Y. Liu, Wastewater ammonia
    removal using an integrated fixed-film activated sludgesequencing
    batch biofilm reactor (IFAS-ISBR): comparison of
    suspended flocs attached biofilm, Int. Biodeterior. Biodegrad.,
    116 (2017) 38–47. 
 
  -  P. Chatterjee, M.M. Ghangrekar, R. Surampalli, Organic matter
    and nitrogen removal in a hybrid upflow anaerobic sludge
    blanket—moving bed biofilm and rope bed biofilm reactor,
    J. Environ. Chem. Eng., 4 (2016) 3240–3245. 
 
  -  A. Tawfik, F. El-Gohary, H. Temmink, Treatment of domestic
    wastewater in an up-flow anaerobic sludge blanket reactor
    followed by moving bed biofilm reactor, Bioprocess. Biosyst.
    Eng., 33 (2010) 267–276. 
 
  -  Z.U. Khan, I. Naz, A. Rehman, M. Rafiq, N. Ali, S. Ahmed,
    Performance efficiency of an integrated stone media fixed
    biofilm reactor and sand filter for sewage treatment, Desal.
    Water Treat., 54 (2015) 2638–2647. 
 
  -  G. Andreottola, P. Foladori, M. Ragazzi, Upgrading of a small
    wastewater treatment plant in a cold climate region using a
    moving bed biofilm reactor (MBBR) system, Water Sci. Technol.,
    41 (2000) 177–185. 
 
  -  J. Jaafari, M. Seyedsalehi, G.H. Safari, M. Ebrahimi Arjestan,
    H. Barzanouni, S. Ghadimi, H. Kamani, P. Haratipour,
    Simultaneous biological organic matter and nutrient removal
    in an anaerobic/anoxic/oxic (A2O) moving bed biofilm reactor
    (MBBR) integrated system, Int. J. Environ. Sci. Technol.,
    14 (2017) 291–304. 
 
  -  J. Jaafari, A.B. Javid, H. Barzanouni, A. Younesi, N. Amir,
    A. Farahani, M. Mousazadeh, P. Soleimani, Performance of
    modified one-stage Phoredox reactor with hydraulic up-flow in
    biological removal of phosphorus from municipal wastewater,
    Desal. Water Treat., 171 (2019) 216–222. 
 
  -  M. Mannacharaju, P. Natarajan, A.K. Villalan, M. Jothieswari,
    S. Somasundaram, S. Ganesan, An innovative approach to
    minimize excess sludge production in sewage treatment using
    integrated bioreactors, J. Environ. Sci., 67 (2017) 67–77. 
 
  -  H. Ødegaard, B. Rusten, J. Siljudalen, The Development of
    the Moving Bed Biofilm Process—From Idea to Commercial
    Product, Proceedings of WEC/EWPCA/IWEM Specialty
    Conference, Innovations 2000, Cambridge, UK, 1998. 
 
  -  H. Ødegaard, B. Gisvold, J. Strickland, The influence of carrier
    size and shape in the moving bed biofilm process, Water Sci.
    Technol., 41 (2000) 383–392. 
 
  -  APHA, Standard Methods for the Examination of Water and
    Wastewater, 21st ed., American Public Health Association,
    Washington, DC, USA, 2005. 
 
  -  X.-b. Hu, K. Xu, Z. Wang, L.-l. Ding, H.-q. Ren, Characteristics
    of biofilm attaching to carriers in moving bed biofilm reactor
    used to treat vitamin C wastewater, Scanning, 35 (2013)
    283–291. 
 
  -  Y. Dong, S.-Q. Fan, Y. Shen, J.-X. Yang, P. Yan, Y.-P. Chen,
    J. Li, J.-S. Guo, X.-M. Duan, F. Fang, S.-Y. Liu, A novel biocarrier
    fabricated using 3D printing technique for wastewater
    treatment, Sci. Rep., 5 (2015) 1–10, doi: 10.1038/srep12400. 
 
  -  L. Kriklavova, T. Lederer, The use of nanofiber carriers in
    biofilm reactor for the treatment of industrial wastewaters,
    Olomouc, 12 (2010) 1–6. 
 
  -  W.G. Characklis, M.G. Trulear, J.D. Bryers, N. Zelver, Dynamics
    of biofilm processes: methods, Water Res., 16 (1982) 1207–1216. 
 
  -  D.W. Garny, Z.D. Wen, B. Li, H. Liang, Sloughing and
    limited substrate conditions trigger filamentous growth in
    heterotrophic biofilms—measurements in flow-through tube
    reactor, Chem. Eng. Sci., 64 (2009) 2723–2732. 
 
  -  Y. Abe, P. Polyakov, S. Skali-Lami, G. Francius, Elasticity and
    physico-chemical properties during drinking water biofilm
    formation, Biofouling, 27 (2011) 739–750. 
 
  -  J. Xu, P. Wang, Y. Li, L. Niu, Z. Xing, Shifts in the microbial
    community of activated sludge with different COD/N ratios or
    dissolved oxygen levels in Tibet, China, Sustainability, 11 (2019)
    2284, doi: 10.3390/su11082284. 
 
  -  M. Duncan, N. Horan, Handbook of Water and Wastewater
    Microbiology, Elsevier Publishers, An Imprint of Elsevier, 84
    Theobald’s Road, London WC1X 8RR, UK, 2003, pp. 25–30. 
 
  -  N.K. Singh, A. Bhatia, A.A. Kazmi, Effect of intermittent
    aeration strategies on treatment performance and microbial
    community of an IFAS reactor treating municipal wastewater,
    Environ. Technol., 38 (2017) 2866–2876. 
 
  -  M. Salazar, Application and importance of microalgae
    in wastewater treatment, Laboratory of Environmental
    Microbiology and Wastewater Treatment, Contactos, 59 (2005)
    64–70. 
 
  -  A.H. Javid, A.H. Hassani, B. Ghanbari, K. Yaghmaeian,
    Feasibility of utilizing moving bed biofilm reactor to upgrade
    and retrofit municipal wastewater treatment plants, Int. J.
    Environ. Res., 7 (2013) 963–972. 
 
  -  A.K. Mungray, K. Patel, Coliforms removal in two UASB + ASP
    based systems, Int. Biodeterior. Biodegrad., 65 (2011) 23–28. 
 
  -  USEPA, Guidelines for Water Reuse, U.S. Environmental
    Protection Agency and U.S. Agency for International
    Development, Washington, DC, EPA-625/R04–108, 2004. 
 
  -  Z.Z. Yang, Z.M. Yang, J.G. Cao, Y.Y. Jia, J.X. Xu, Study on the
    combination of fixed bed and moving bed biofilm reactor for
    papermaking terminal wastewater treatment, Adv. Mater. Res.,
    777 (2013) 309–313. 
 
  -  A. Aygun, B. Nas, A. Berktay, Influence of high organic loading
    rates on COD removal and sludge production in moving
    bed biofilm reactor, Environ. Eng. Sci., 25 (2008) 1311–1316. 
 
  -  B. Ma, S. Wang, G. Zhu, S. Ge, J. Wang, N. Ren, Y. Peng,
    Denitrification and phosphorus uptake by DPAOs using nitrite
    as an electron acceptor by step-feed strategies, Front. Environ.
    Sci. Eng., 7 (2013) 267–272. 
 
  -  S.-Q. Ni, J.-Y. Ni, D.-L. Hu, S. Sung, Effect of organic matter
    on the performance of granular anammox process, Bioresour.
    Technol., 110 (2012) 701–705. 
 
  -  C. Dale, M. Laliberte, D. Oliphant, M. Ekenberg, Wastewater
    Treatment Using MBBR in Cold Climates, Proceedings of
    Mine Water Solutions in Extreme Environments, InfoMine,
    Vancouver, Canada, April 12–15, 2015. 
 
  -  R. Peñafiel, C. Moreno, V. Ochoa-Herrera, Removal of nitrogen
    and organic pollution from pre-treated industrial wastewater
    in anaerobic lagoons using a sand biofilter, ACI Avances en
    ciencias e ingenierías, 8 (2016) 63–74. 
 
  -  J.H. Guo, Q. Yan, Y.Z. Peng, A. Yang, S. Wang, Biological
    nitrogen removal with real-time control using step-feed SBR
    technology, Enzyme Microb. Technol., 40 (2007) 1564–1569. 
 
  -  J. Ma, Y.Z. Peng, S.Y. Wang, L. Wang, Y. Liu, N.P. Ma,
    Denitrifying phosphorus removal in a step-feed CAST with
    alternating anoxic-oxic operational strategy, J. Environ. Sci.,
    21 (2009) 1169–1174. 
 
  -  P.A. Wilderer, P. Arnz, E. Arnold, Application of biofilms and
    biofilm support materials as a temporary sink and source,
    Water Air Soil Pollut., 123 (2000) 147–158. 
 
  -  R.M. Ramos, P.J.F. Muñoz, M.J.C. Saldarriaga, Effect of
    anaerobic-oxic-anoxic-anoxic (OAA) sequence on the removal
    of organic matter, phosphorus, and nitrogen in a modified
    laboratory scale SBR, Ingeniare. Rev. Chil., 25 (2016) 477–491. 
 
  -  J. Palma, J. Manga, Simulation of a batch activated sludge (SBR)
    system for the treatment of wastewater with high nitrogen
    content, Ingeniería & Desarrollo, 18 (2005) 61–71. 
 
  -  Z.X. Peng, Y.Z. Peng, L.J. Gui, X.L. Liu, Competition for single
    carbon source between denitrification and phosphorus release
    in sludge under anoxic condition, Chin. J. Chem. Eng., 18 (2010)
    472–477. 
 
  -  X.J. Wang, S.Q. Xia, L. Chen, J.F. Zhao, N.J. Renault,
    J.M. Chovelon, Nutrients removal from municipal wastewater
    by chemical precipitation in a moving bed biofilm reactor,
    Process Biochem., 41 (2006) 824–828. 
 
  -  A. Moawad, U.F. Mahmoud, M.A. El-Khateeb, E. El-Molla,
    Coupling of sequencing batch reactor and UASB reactor for
    domestic wastewater treatment. Desalination, 242 (2009)
	  325–335.