Biodegradation of high concentrations of benzene vapors in a two phase partition stirred tank bioreactor

Abstract

The present study examined the biodegradation rate of benzene vapors in a two phase stirred tank bioreactor by a bacterial consortium obtained from wastewater of an oil industry refinery house. Initially, the ability of the microbial consortium for degrading benzene was evaluated before running the bioreactor. The gaseous samples from inlet and outlet of bioreactor were directly injected into a gas chromatograph to determine benzene concentrations. Carbone oxide concentration at the inlet and outlet of bioreactor were also measured with a CO2 meter to determine the mineralization rate of benzene. Influence of the second non-aqueous phase (silicon oil) has been emphasized, so at the first stage the removal efficiency (RE) and elimination capacity (EC) of benzene vapors were evaluated without any organic phase and in the second stage, 10% of silicon oil was added to bioreactor media as an organic phase. Addition of silicon oil increased the biodegradation performance up to an inlet loading of 5580 mg/m3, a condition at which, the elimination capacity and removal efficiency were 181 g/m3/h and 95% respectively. The elimination rate of benzene increased by 38% in the presence of 10% of silicone oil. The finding of this study demonstrated that two phase partition bioreactors (TPPBs) are potentially effective tools for the treatment of gas streams contaminated with high concentrations of poorly water soluble organic contaminant, such as benzene.

Heavy Metal Contamination in Rice-Producing Soils of Hunan Province, China and Potential Health Risks

“…The mean Cd level in brown rice was 0.312 mg/kg, which exceeded values from areas influenced by industrial activities such as e-waste processing [ 42 ]. The estimated daily intake of Cd through brown rice consumption had been reported to be 35.4 μg/day in Iran [ 43 ], 5.38 μg/day in South Korea [ 44 ] and 11.7 μg/day in Japan [ 45 ]. It was estimated be 600 μg/day in the late 1960s for the local population in the Jinzu river basin in Japan [ 46 ].…”

Assessment of Oxidative Stress in Patients with an Isolated Traumatic Brain Injury Using Disposable Electrochemical Test Strips

“…The maximal productivity achieved in the present TiTR system was 38 times higher than that achieved in other stirred batch reactors because of high substrate mass transfer rates. Obtaining such high productivities in three‐phase stirred batch reactors is often limited owing to the stirring speed, which sets a trade‐off between substrate mass transfer31 and enzyme inactivation from the generated shear stress 21…”

Magnetic heterogeneous catalytic ozonation: a new removal method for phenol in industrial wastewater

“…25 g of the modified AC was dispersed in 200 ml aqueous solution containing 100 g Fe (NO3)3 · 9H2O as a Fe 3 O 4 precursor by sonication using an ultrasonic bath. The resulting particles then filtrated, dried and the thermal treatment was performed at 700°C for 1 h in the presence of pure nitrogen flow for the formation of Fe3O4 magnetic nano particles [19]. …”