Bioactive adsorber model for industrial wastewater treatment

A predictive mathematical model that describes the adsorption and biodegradation phenomena in recycle fluidized-bed (RFB) adsorbers was developed. The model incorporated liquid film transfer, biodegradation and diffusion in the biofilm, adsorption onto activated carbon, and biofilm growth. The model equations were solved by a combinatorial technique involving the methods of orthogonal collocation and finite differences. Computer simulations of the model were used for adsorber performance predictions from parameters obtained from adsorption equilibrium and kinetic studies, biokinetic experiments, and correlation techniques. Sensitivity tests were also performed to determine the effect of physical and biological parameters on model profiles. Recycle fluidized adsorber experiments were conducted to test the predictive capability of the model. Two ideally biodegradable compounds, glucose and sucrose, as well as two actual wastewaters, a dairy waste and a landfill leachate, were used to compare the predicted model profiles with experimental data for nonbioactive and bioactive RFB adsorbers. The performance predictions obtained from modeling were in satisfactory agreement with the experimental data.