Biodegradation of BTEX: Optimization through Response Surface Methodology

Response Surface Methodology (RSM) was used to optimize the biodegradation of Benzene, Toluene, Ethyl benzene and m-, o-, p-Xylene (BTEX) by Pseudomonas putida immobilized in PVA matrices in a specially-designed novel Spouted Bed Bioreactor System (SBBS). A mixture of 60 mg L^-1 of BTEX compounds in air was contacted with the immobilized bacteria in three spouted bed bioreactors in series. The parameters investigated include the contaminated air flow rate, operating temperature, PVA volume and water pH. Maximum biodegradation efficiency was predicted to occur at an air flow rate of 500 mL min^-1, an operating temperature of 33°C, a PVA volume fraction of 30% and a pH of 8.3. Among the evaluated variables, air flow rate had the most significant effect on the efficiency of BTEX biodegradation. At optimum conditions, the novel bioreactor system was able to achieve maximum removal efficiency of 94, 98, 95 and 98% for Benzene, Toluene, Ethylbenzene and Xylene, respectively.