Equilibrium, kinetics, and column dynamics of methyl ethyl ketone biodegradation

Equilibrium and kinetic studies of methyl ethyl ketone (MEK) adsorption in compost and granular activated carbon (GAC), the reaction rate and selectiv ity of microorganisms for MEK biodegradation, and the role of the adsorptio n capacity of the support medium on biofilter dynamics are investigated in this study. Experiments on MEK degradation using biofilters with either Rho dococcus sp. or a mixed culture showed comparable results, indicating no ad vantage of a pure culture of Rhodococcus sp. The equilibrium isotherm of ME K in compost is linear in the entire range of concentration typically encou ntered in biofilters, but on GAC the isotherm is nonlinear. Investigation o n adsorption kinetics suggests that the mass transfer is macropore-controll ed in both compost and GAG. However, in compost the transport appears to be by molecular diffusion, whereas in GAC it is by a combination of molecular , Knudsen, and surface diffusion. Experimental results show that GAC is bet ter than compost in terms of pollutant removal and handling of the fluctuat ing input load. A linear driving force approximation is used to describe th e transport of solute from the gas phase to the support phase. The resultin g linear driving force biofiltration model, using independently measured eq uilibrium and kinetic parameters, appears adequate for describing the exper imental results of biofilter dynamics.