Mathematical models of a fluidized bed bioreactor using granular activated carbon (FBBR-GAC) for wastewater treatment

Abstract

This study aimed to developmathematical modelsofa novel recirculation plug-flow reactor (RPFR) and recirculation completely-mixed stirred tank reactors(RCSTR). Itwas doneevaluateand predict wastewater treatment performance using a fluidized bed bioreactor with granular activated carbon (FBBR-GAC).Wastewaters from householdwashing activitiesand from an industrial dairy process were used in theseexperiments. The highest COD removal (>90%) from thetwo wastewaters were achieved at recirculation ratio (R) of 936. The kinetic results showed that the rate of COD removal from the twotypes of wastewater used with FBBR-GAC reactors followed 2nd order kinetic models,with k2,RPFR values of 4.68 x 10-2and 2.81x10-2mg-1Ld-1for washingand dairy wastewaters, respectively. Additionally, we found that the RPFR model was more suitable fordescribingthe behavior oftheFBBR-GAC system than the RCSTR model. The developed RPFRmodel can precisely predictthe effluent COD of wastewater at the optimum rate of recirculation (R) 936, and optimum rate ofthebed's stirrer speed (NB)25 rpm. Based on the optimum R and kinetic model, the developed RPFR model can be used to predict the COD reduction overtime. For a continuous process, an optimalflowrate can be obtained from the HRT that givesthe desired COD removal at a givenreactor volume.

Keywords

• Mathematical models
• Recirculation bioreactor
• Granular activated carbon (GAC)
• Wastewater