Biodegradation Modeling of Nitrophenolic Pollutant in a Slurry Bubble Reactor

Biodegradation kinetics of 4-nitrophenol (PNP) in aqueous solution by a gram negative soil bacterium, Ralstoniaeutropha was firstly studied in a small scale batch reactor. The degradation of PNP was evaluated at initial PNP concentrations ranging from 3 mg/L to 14 mg/L. The rate of PNP consumption by the bacterium culture was modeled using Monod and Contois kinetics in batch condition. PNP degradation by adapted R. eutropha was well fitted to the Monod equation for the pollutant with initial concentration of 3-8 mg/L, whereas for PNP with initial concentration of 14 mg/L the experimental data were better fitted to the Contois kinetic model. The process of degradation of PNP was scaled up in a slurry bubble reactor with 250 ml working volume in presence of 0.75 L/min air flow rate. The derived kinetic model was validated by comparison the outlet time dependent experimental data of PNP concentration with the model in the slurry bioreactor and the results showed good agreement between experiments and the model.