airpollution control

جزوه آموزشی دکتر نیک پی - کنترل آلودگی هو

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جزوه آموزشی دکتر نیک پی - انتشار گرد و غبار

Aerobic biodegradation of per-treated methyl tert-butyl ether by ozonation in an up-flow-fixed-bed reactor

Problem Statement: MTBE is a common pollution of environmental and has become an issue of considerable concern in recent years. It is not readily amenable to remove MTBE by conventional techniques in water treatment. In the present study, the feasibility of the continuous aerobic biodegradation of MTBE, was evaluated in an Up- Flow Fixed Bed Reactor (UFBR). Approach: The UFBR at a constant Hydroulic Retention Time (HRT) of 24 h was used as a biological process that receives the intermediates due to partial oxidation of MTBE. The UFBR coupled to ozonation process as a survey system after a primary operation phase that was necessary for creatory of an initial microbial film on the carriers. Residual concentration of MTBE and its major degradation intermediates were measured by gas chromatography. Aqueous concentration of ozone in the reactor and ozone average concentration in off- gas were determined according to the indigo blue method. The COD reduction and BOD5 to COD ratio were selected as biodegradability indexes. Results: Results showed an effective degradation of MTBE in the coupled ozonation-UFBR continuous flow reactor of ten days of operation time. A partial degradation of MTBE in AOPs increases its biodegradation The BOD5 to COD ratio increased from lowest (0.01) up to a maximum of 0.72 that corresponds to an ozone consumption of 0.62mg per each mg of COD initially present in the solution. The results showed when m. MolMTBEo/m. Mol(o3) = 0.611, the COD removal efficiency was 89% and as this ratio increased up to 1.25, the of COD removal efficiency decreased to 80%. 46-68% removal of the COD was needed before the mixture was considered biodegradable. The highest removal rate of MTBE, 82.91 mg day-l achieved through out the UFBR runs (87% removal efficiency, In this study, the removal efficiency of MTBE using integrated-process (ozonation followed biological treatment) was from 78.5-86.5%. In order to determine of biological removal rate of MTBE, another UFBR system used as a blank reactors. Results showed that the efficiency of the COD removal (by stripping with the biological degradation) was 5-8% which implies insignificant biological removal of MTBE without pre-ozonation. Solid produced in the proposed integrated process was 0.27-0.35 kg TSS kg-1 COD removed which is approximately in down range of conventional biological system (0.3-0.5 kg TSS kg-1COD). Conclusion: Present study showed that we can treatment of the polluted aqueous solutions to MTBE without microbial incubation used to integrated process. © 2009 Science Publications

Purification polluted Air with Toluene Vapor by self cleaning DBD cold plasma Filter combined with alumina adsorbent

Background and aims: In recent decades, non-thermal plasma technology has been developed as a novel technology in controlling volatile organic compounds. The main problem with this method is Production of byproducts, high energy consumption and the short duration of the presence of the pollutant in the oxidizing range which in turn reducing the probability of oxidation. Accordingly, this study was conducted aimed to investigate the effect of cold plasma reactor (dielectric barrier discharging) Integration with alumina adsorbent on the efficiency of Toluene vapor removal and optimization of operating conditions in plasma reactor and combined plasma reactors. Material and Methods The study was conducted in a laboratory reactor in the dimensions of the table. In order to investigate the effect of the integration of cold plasma reactors with alumina adsorbent, 42 series of experiments were designed. In each experiment, at first, the efficiency of removing the plasma reactor by passing a certain concentration of Toluene from the reactor, then making the plasma and measuring the concentration of Toluene in the output of reactor was calculated. Then reactor filled with alumina adsorbent and each experiment was carried out in two steps of adsorption and oxidation. Thus, at the absorption stage, the air flow containing a specific concentration of Toluene was passed through the adsorbent after reaching the absorbent breakthrough, the flow of Toluene was discontinued and with the passage of clean air and the formation of plasma, the accumulated pollutant on surface of the adsorbent oxidized and removal efficiency was calculated. Results: The results showed that the integration of the plasma reactor with adsorbent resulted in increased removal efficiency from 91% to 98% and doubling the capacity elimination in optimal conditions. Also, the amount of carbon dioxide production increased from 54 to 104 ppm in optimal conditions. In the plasma reactor, concentration and flow have an inversely correlation with the removal efficiency But the combination of the plasma reactor with the alumina adsorbent led to an increase in removal efficiency by increasing concentrations and flow. On the other hand adsorption capacity increased with increasing concentrations. Conclusion: The use of alumina adsorbent in plasma range while increasing removal efficiency as well as elimination capacity, providing the necessary conditions for discontinuous utilization of plasma and saving energy. Keywords: Non-thermal Plasma, Dielectric Barrier Discharge, Volatile Organic Compound, Oxidation, Adsorbent, Toluen