Journal of Health and Safety at Work

Introduction: Human and environment exposed to harmful factors, as the result of industrial pollutants. Volatile organic compounds (VOCs) play important role in photochemical reactions in troposphere layer of atmosphere and results in production of ozone and photochemical oxidants.

.

Material and Method: In this study, a miniature stirred tank bioreactor was designed for treatment of waste gas containing xylene. In the next step, the bioreactor incubated with microbial consortiums with ratio of 1 to 3. The performance of bioreactor in treatment of xylene vapors in presence of 10% silicone oil, as an organic phase was assessed in concentrations ranging from 551 mg/m3 to 3330 mg/m3 for 432 hours.

.

Result: The results of xylene biodegradation showed that removal efficiency up to the concentrations of 2756 mg/m3 was 82 percent. Moreover, adding 10% silicone oil increased removal efficiency of BTX by 85.7% in comparison with context without organic phase. The microbiological experiments on the bioreactor media showed that three spices of Pseudomonas putida, Chryseobacterium and Ralstonia pickettii were found, in the presence of xylene.

 .

Conclusion: Overall, the results of the present research revealed that application of two phase stirred tank bioreactors (TPPBs) for xylene from contaminated treatment of streams was successful.

Introduction: In real Conditions, pollution emission are mostly released as mixed components rather than a single pure emission of the chemicals. In this study, a miniature stirred tank bioreactor was optimized for treatment of waste gas containing BTX (benzene, toluene and xylene).

.

Material and Method: The sludge of an oil refinery was sampled based on the assumption that it contains BTX-degrading microorganisms and used as microbial consortium. Also, silicone oil was added to improve removal efficiency. The operational parameters of the bioreactor were optimized during the study.

.

Result: The removal efficiency and elimination capacity of benzene, toluene and xylene vapors simultaneously in the presence of 10% silicone oil as an organic phase showed increasing trend up to the concentrations of 1730 mg/m3, 1710 mg/m3 and 1380 mg/m3, respectively. In these concentrations the removal efficiency and elimination capacity of benzene were 100% and 59 g/m3/h, toluene 100% and 58 g/m3/h and xylene 91% and 42 g/m3/h, respectively. The total removal efficiency and elimination capacity for BTX were 91 to 100% and 159 g/m3/h, respectively.

.

Conclusion: It was shown that presence of 10% silicone oil increased 44.5% in total removal efficiency of BTX. The microbiological experiments on the bioreactor media showed that three spices of Pseudomonas putida, Chryseobacterium and Ralstonia pickettii can be found, when BTX ware treated. This work revealed that two phase partition bioreactors (TPPBs) can be successful method for the treatment of streams contaminated with BTX.

Introduction: Volatile organic compounds such as xylene, which are the main constituents of the oil and petrochemical industries, have serious impacts on health and can cause adverse effects on the environment. It is clear that release of these compounds into the environment should be controlled. The two-phases partitioning stirred tank bio-reactor is one of the newest methods for treating these compounds which have few side-effects besides of having appropriate efficiency since itdestroyscontaminant completely and transform it tosafer compounds.

.

Material and Method: In this study, a two phase partitioning stirred tank bio-reactor, in lab scale, was used for treating the gas stream containing xylene vapors. The aqueous phase containing the bacteria Pseudomonas putida and nutrients inserted into the bioreactor with 3:1 ratio and system performance was evaluated for 432 hours in the concentration range of 1000 mg/m3 to 3500 mg/m3

.

Result: Empirical findings of this study showed that the maximum, minimum and average of removal of xylene vapors by stirred two phase bioreactor containing a pure strain of Pseudomonas putida were 94.00, 54.00 and 84.94 percent, respectively.Furthermore, maximum, minimum and average of elimination capacity of xylene were obtained 93.00,24.00 and 62.02 g/m3/h, respectively

.

Conclusion: Overall, the results of the present research revealed that the application of two phase stirred tank bioreactors (TPPBs) containing pure strains of Pseudomonas putida was successful for treatment of air streams with xylene.