Studies on optimization of naphthalene biodegradation using surface response methodology: Kinetic study and performance evaluation of a pilot scale integrated aerobic treatment plant

Abstract

In the present work, the biodegradation of naphthalene (polycyclic aromatic hydrocarbon) has been studied using isolated Bacillus cereus RKS4 (MH681588.1). The process variables such as pH (5.0–9.0), temperature (25–40 °C), and naphthalene concentration (10–50 mg/L) have been optimized using central composite design (CCD) of response surface methodology (RSM). Analysis of variance (ANOVA) shows a high value of R2 (0.98) and confirm that the second-order regression model is in agreement with experimental data. The maximum removal of naphthalene (96.1%) were obtained at pH of 7.0, naphthalene concentration of 10 mg/L, and temperature of 32.0 °C. Further, the biodegradation of naphthalene was studied in a pilot-scale integrated aerobic treatment plant (IATP) at various flow rates. GC–MS analysis reveals that catechol and 2-naphthol were the major intermediate metabolites observed during biodegradation. The kinetics of naphthalene biodegradation was examined by Monod and Teissier-Edwards models and kinetic parameters were obtained to be μmax: 0.165 per day, KS: 7.91 mg/L by Monod and μmax: 0.321 per day, KS: 11.5 mg/L, Ki: 33.2 mg/L by Teissier-Edwards. © 2019 Institution of Chemical Engineers