References
   -  J.F. Richardson, W.N. Zaki, Sedimentation and fluidization,
    Trans. Inst. Chem. Eng., 32 (1954) 35–52. 
-  H.M. Jena, G.K. Roy, B.C. Meikap, Hydrodynamics of a gas-liquid-solid fluidized bed with hollow cylindrical particles,
    Chem. Eng. Process. Process Intensif., 48 (2008) 279–287. 
-  L.S. Fan, Gas-Liquid-Solid Fluidization Engineering, Butterworth
    Series in Chemical Engineering, Butterworth, Boston,
    MA, 1989. 
-  J.M. Begovich, J.S. Watson, Hydrodynamic Characteristics of
    Three-Phase Fluidized Beds, J.F. Davidson, D.L. Keairns, Eds.,
    Fluidization, Cambridge University Press, Cambridge, 1978,
    pp. 190–195. 
-  M.M. Bello, A.A.A. Raman, M. Purushothaman, Applications
    of fluidized bed reactor in wastewater treatment – a review of
    the major design and operational parameters, J. Cleaner Prod.,
    141 (2017) 1492–1514. 
-  A. Aguirre-Sierra, T.B.-D. Gregoris, A. Berná, J.J. Salas,
    C. Aragón, A. Esteve-Núñez, Microbial electrochemical
    systems outperform fixed-bed biofilters in cleaning up urban
    wastewater, Environ. Sci. Water Res. Technol., 2 (2016)
    984–993. 
-  S. Tejedor-Sanz, J.M. Ortizc, A. Esteve-Núñez, Merging
    microbial electrochemical systems with electrocoagulation
    pretreatment
    for achieving a complete treatment of brewery
    wastewater, Chem. Eng. J., 330 (2017) 1068–1074. 
-  K. Ostergaard, P.I. Theisen, The effect of particle size and bed
    height on the expansion of mixed phase (gas—liquid) fluidized
    beds, Chem. Eng. Sci., 21 (1966) 413–417. 
-  P. Dakshinamurthy, V. Subramanian, J.N. Rao, Bed porosities
    in gas-liquid fluidization, Ind. Eng. Chem. Process Des. Dev.,
    10 (1971) 322–328. 
-  S.D. Kim, C.G.J. Baker, M.A. Berjougnou, Phase holdup
    characteristics of three-phase fluidized beds, Can. J. Chem.
    Eng., 53 (1975) 134–139. 
-  I. Nikov, B.P.A. Grandjean, P.J. Carreau, J. Paris, Viscosity
    effects in cocurrent three-phase fluidization, AIChE J., 36 (1990)
    1613–1616. 
-  D.H. Lee, J.R. Grace, N. Epstein, Gas holdup for high gas
    velocities in a gas-liquid cocurrent upward-flow system, Can.
    J. Chem. Eng., 78 (2000) 1006–1010. 
-  K. Ramesh, T. Murugesan, Minimum fluidization velocity and
    gas holdup in gas-liquid-solid fluidized bed reactors, J. Chem.
    Technol. Biotechnol., 77 (2002) 129–136. 
-  H. Miura, Y. Kawase, Hydrodynamics and mass transfer in
    three-phase fluidized beds with non-Newtonian fluids, Chem.
    Eng. Sci., 52 (1997) 4045–4104. 
-  V. Sivakumar, K. Senthilkumar, P. Akilamudhan, Prediction of
    liquid holdup and solid holdup in three-phase fluidized bed:
    air/Newtonian and non-Newtonian liquid systems, Biochem.
    Eng. Q., 22 (2008) 401–410. 
-  H. Miura, T. Takahashi, Y. Kawase, Effect of pseudo plastic
    behavior of liquid in co-current three phase fluidized beds on
    bed expansion, Chem. Eng. Sci., 56 (2001) 6047–6053. 
-  V. Sivakumar, K. Senthilkumar, Prediction of minimum
    fluidization velocity in two-phase and three-phase fluidized
    beds: air/Newtonian and non-Newtonian liquids, Int. J. Chem.
    Reactor Eng., 8 (2010) 1–18. 
-  P. Znidarsic, A. Pavko, The morphology of filamentous fungi
    in submerged cultivations as a bioprocess parameter, Food
    Technol. Biotechnol., 39 (2001) 237–252. 
-  V. Sivakumar, K. Senthilkumar, T. Kannadasan, Prediction of
    gas holdup in the three-phase fluidized bed: air/Newtonian and
    non-Newtonian liquid systems, Pol. J. Chem. Technol., 12 (2010)
    64–71. 
-  D.T.K. Dora, Y.K. Mohanty, G.K. Roy, B. Sarangi, Prediction of
    bed fluctuation and expansion ratios for homogeneous ternary
    mixtures of spherical glass bead particles in a three‐phase
    fluidised bed, Chem. Eng. Commun., 202 (2014) 765–773. 
-  H. Pan, Y. Li, N. Li, F. Gao, X. Fu, R. Zhu, G. Evans, Study on gas
    holdup in a fluidized flotation column from bed pressure drop,
    Energy Sources Part A, 40 (2018) 1693–1700. 
-  R.K. Padhi, D.T.K. Dora, Y.K. Mohanty, G.K. Roy, B. Sarangi,
    Hydrodynamics of three-phase fluidization of homogeneous
    ternary mixture in a conical conduit—experimental and
    statistical analysis, Chin. J. Chem. Eng., 2016 (24) 1335–1343. 
-  D.T.K. Dora, Y.K. Mohanty, G.K. Roy, Hydrodynamics of
    three-phase fluidization of a homogeneous ternary mixture of
    irregular particles, Chem. Eng. Sci., 79 (2012) 210–218. 
-  A.H. Sulaymon, T.J. Mohammed, A.H. Jawad, Hydrodynamic
    characteristics of three-phase non-Newtonian liquid–gas–solid
    fluidized beds, Emirates J. Eng. Res., 15 (2010) 41–49. 
-  H.M. Jena, G.K. Roy, S.S. Mahabatra, Determination of optimum
    gas holdup conditions in a three-phase fluidized bed by genetic
	  algorithm, Comput. Chem. Eng., 34 (2010) 476–484.