| Summary: | 碩士 === 國立交通大學 === 生化工程研究所 === 97 === According to the foregoing investigation, the biotechnologies has been proven to be an effective process for treating volatile organic compounds(VOCs). The goals of this study were to extend the previous study to removal toluene and ethylbenzene. We examined the effects of inlet concentration, retention time(RT), pH of the nutrient feed, nutrient feeding frequency, material and nitrogen source on the biofilter performance for treating toluene and ethylbenzene waste gases.
When the retention time was 0.5 min, the toluene and ethylbenzene removal efficiency increased as the pH of the nutrient feed increased in the pH range of 5-7 . However, an opposite trend was observed for pH between 7 and 9. The optimum pH range was 7. Nutrient feeding frequency test was three conditions: all day, 15 min/h and 30 min/day.When the nutrient feeding frequency was 15 min/h, the toluene and ethylbenzene removal efficiency was significantly higher than the other. The development of biomass accumulation is related to the bed pressure drop in the biofilter, and it can cause the bed clogging and channelling. As can be observed, the pressure drop increased as gas flow rate was increased. The pressure drop significantly increased after biomass accumulation in the biofilter. The experimental results indicated that toluene and ethylbenzene could be effectively removed when the nitrogen source was (NH4)2SO4. Moreover, when KNO3 was added or not provid nitrogen source, the bacterial growth and pollution degradation became limited. Experiments at various toluene and ethylbenzene inlet loads were carried out. The toluene maximum elimination capacity was 157gm-3h-1 for an inlet loads 192 gm-3h-1. The ethylbenzene maximum elimination capacity was 302 gm-3h-1 for an inlet loads of 419 gm-3h-1.
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