Direct Comparison of Fluidized and Packed Bed Bioreactors for Bioremediation of an Air Pollutant

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Kyla Clarke ◽  
Gordon A Hill ◽  
Todd S. Pugsley
Keyword(s):  
Packed Bed ◽  
Air Pollutant ◽  
Fluidized Bed Bioreactor ◽  
Transfer Rates ◽  
Waste Gas ◽  
Glass Spheres ◽  
Fluidized Bioreactor ◽  
Volatile Organic ◽  
Fluid Bed ◽  
Maximum Elimination Capacity

A gas-solid fluidized bed bioreactor has been successfully used for the bioremediation of ethanol (a model volatile organic compound, VOC) contaminated air. A key objective of this fluidized bioreactor study was to compare the performance of fluid bed operation to packed bed operation. A fluid bed system increased homogeneity and improved upon operating problems such as plugging and channelling normally associated with packed bed bioreactors. The bioreactor bed was comprised of a mixture of moist sawdust particles and glass spheres. Depending on the superficial velocity of the waste gas stream, the bioreactor could be operated in either packed or fluidized mode. During fluid bed operation, the sawdust and glass sphere mixture was maintained in a bubbling/slugging regime. As expected, fluid bed operation demonstrated significantly higher mass transfer rates but the maximum elimination capacity was 75 g m-3sawdust h-1 as compared to 225 g m-3sawdust h-1 for packed bed operation. In packed bed mode, higher ethanol concentrations were used in order to have comparable ethanol loadings and this may have contributed to faster growth rates and thus faster bioremediation rates.

scholarly journals Influence of Alumina Precursor Properties on Cu-Fe Alumina Supported Catalysts for Total Toluene Oxidation as a Model Volatile Organic Air Pollutant

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 252
Author(s):  
Tadej Žumbar ◽  
Alenka Ristić ◽  
Goran Dražić ◽  
Hristina Lazarova ◽  
Janez Volavšek ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Iron Concentration ◽  
Catalytic Performance ◽  
Air Pollutant ◽  
Molar Ratio ◽  
Homogeneous Distribution ◽  
Total Oxidation ◽  
Alumina Support ◽  
Determining Factors ◽  
Volatile Organic

The structure–property relationship of catalytic supports for the deposition of redox-active transition metals is of great importance for improving the catalytic efficiency and reusability of the catalysts. In this work, the role of alumina support precursors of Cu-Fe/Al2O3 catalysts used for the total oxidation of toluene as a model volatile organic air pollutant is elucidated. Surface characterization of the catalysts revealed that the surface area, pore volume and acid site concentration of the alumina supports are important but not the determining factors for the catalytic activity of the studied catalysts for this type of reaction. The determining factors are the structural order of the support precursor, the homogeneous distribution of the catalytic sites and reducibility, which were elucidated by XRD, NMR, TEM and temperature programed reduction (TPR). Cu–Fe/Al2O3 prepared from bayerite and pseudoboehmite as highly ordered precursors showed better catalytic performance compared to Cu-Fe/Al2O3 derived from the amorphous alumina precursor and dawsonite. Homogeneous distribution of FexOy and CuOx with defined Cu/Fe molar ratio on the Al2O3 support is required for the efficient catalytic performance of the material. The study showed a beneficial effect of low iron concentration introduced into the alumina precursor during the alumina support synthesis procedure, which resulted in a homogeneous metal oxide distribution on the support.

Performance of a pilot-scale cross-flow rotating packed bed in removing VOCs from waste gas streams

2006 ◽  
Vol 52 (2) ◽  
pp. 274-279 ◽  
Author(s):  
Chia-Chang Lin ◽  
Tzu-Ying Wei ◽  
Shu-Kang Hsu ◽  
Wen-Tzong Liu
Keyword(s):  
Cross Flow ◽  
Packed Bed ◽  
Pilot Scale ◽  
Waste Gas ◽  
Gas Streams ◽  
Rotating Packed Bed ◽  
Waste Gas Streams

scholarly journals Importance of Meteorology and Chemistry in Determining Air Pollutant Levels During COVID-19 Lockdown in Indian Cities

2021 ◽  
Author(s):  
Leigh Crilley ◽  
Yashar Iranpour ◽  
Cora J. Young
Keyword(s):  
Atmospheric Chemistry ◽  
Field Measurements ◽  
Air Pollutant ◽  
Mitigation Strategies ◽  
Ozone Production ◽  
Linear Relationships ◽  
Regional Sources ◽  
Volatile Organic ◽  
Emission Changes ◽  
Indian Cities

To accurately quantify impact of short-term interventions (such as COVID-19 lockdown) on air pollutant levels, meteorology and atmospheric chemistry need to be considered in addition to emission changes. We demonstrate that regional sources have a significant influence on PM<sub>2.5 </sub>levels in Delhi and Hyderabad due to the small reduction calculated post-lockdown after weather-normalization, indicating that future PM<sub>2.5</sub> mitigation strategies should focus on national-scale, as well as local sources. Furthermore, we demonstrate with field measurements that ozone production in Delhi is likely volatile organic compound (VOC)-limited, in agreement with previous modelling predictions, indicating that ozone mitigation should focus on dominant VOC sources. This work highlights the complexity in developing mitigation strategies for air pollution due to its non-linear relationships with emissions, chemistry and meteorology.

Experimental Study of Droplet Biofilter Packed with Green Sphagnum

2017 ◽  
Author(s):  
Erika Petrauskaitė ◽  
Rasa Vaiškūnaitė
Keyword(s):  
Experimental Study ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Lower Layer ◽  
High Flow ◽  
Plant Structure ◽  
Waste Gas ◽  
Air Cleaning ◽  
Volatile Organic ◽  
Different Types

Air cleaning from VOC (volatile organic compunds) group of contaminants could be done by using different types of methods: adsoption, absorption, chemical or thermal oxidation. However, the most promising method is biological air cleaning. Biofilters have found most of their success in the treatment of dilute high-flow waste gas sreams containing odors or volatile organic compounds. To evaluate the meaning of the applicability of green sphagnum use in the droplet biofilter we will make the research. Sphagnum as a plant has big capabilities to absorb water and hold it in the porous parts plant structure. This characteristic of the plant could affect the water flow in the lower layer of the biolfiltrer and in this case will change the possibility to microorganisms to create right envinment to absorb and degrade the polluted air. The main aim of this research is the experimental study of droplet biofilter packed with green sphagnum.

scholarly journals Styrene and Bioaerosol Removal from Waste Air with a Combined Biotrickling Filter and DBD–Plasma System

2020 ◽  
Vol 12 (21) ◽  
pp. 9240
Author(s):  
Steffen Helbich ◽  
Daniel Dobslaw ◽  
Andreas Schulz ◽  
Karl-Heinrich Engesser
Keyword(s):  
Energy Levels ◽  
Biotrickling Filter ◽  
Dbd Plasma ◽  
Combined System ◽  
Waste Gas ◽  
Process Gas ◽  
Volatile Organic ◽  
Waste Air ◽  
Specific Input Energy ◽  
Non Thermal Plasma

A combined system of a biotrickling filter and a non-thermal plasma (NTP) in a downstream airflow was operated for 1220 days for treatment of emissions of styrene and secondary emissions of germs formed in the biological process. The biotrickling filter was operated at variable inlet concentrations, empty bed residence times (EBRT), type and dosage of fertilizers, irrigation densities, and starvation periods, while dielectric barrier discharge and corona discharge were operated at different specific input energy levels to achieve optimal conditions. Under these conditions, efficiencies in the removal of volatile organic compounds (VOCs), germs and styrene of 96–98%, 1–4 log units and 24.7–50.1 g C m−3 h−1 were achieved, respectively. Fluid simulations of the NTP and a germ emission-based clocking of the discharge reveal further energy saving potentials of more than 90%. The aim of an energy-efficient elimination of VOCs through a biotrickling filter and of secondary germ emissions by a NTP stage in a downstream airflow for potential re-use of purified waste gas as process gas for industrial application was successfully accomplished.

scholarly journals Characterization of Volatile Organic Compound (VOC) Emissions from Swine Manure Biogas Digestate Storage

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 411 ◽  
Author(s):  
Yu Zhang ◽  
Zhiping Zhu ◽  
Yunhao Zheng ◽  
Yongxing Chen ◽  
Fubin Yin ◽  
...  
Keyword(s):  
Organic Compound ◽  
Volatile Organic Compound ◽  
Total Concentration ◽  
Swine Manure ◽  
Air Pollutant ◽  
Mitigation Strategies ◽  
Halogenated Hydrocarbons ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Biogas Digestate

Livestock manure is one of the major sources of volatile organic compound (VOC) emissions; however, characteristics of VOCs emitted from biogas digestate (BD) storage, which is a common manure practice, remain unclear. The objective of this study was to characterize VOC emissions during BD storage through the dynamic emission vessel method, to identify the VOC emissions that have potential odor and/or toxic effects. The results revealed the detection of 49 VOCs with seven classes, whose total concentration varied from 171.35 to 523.71 μg m−3. The key classes of the 49 VOCs included Oxygenated VOCs (OVOCs), olefins and halogenated hydrocarbons. The top four compositions, accounting for 74.38% of total VOCs (TVOCs), included ethanol, propylene, acetone and 2-butanone. The top four odorous VOCs, accounting for only 5.15% of the TVOCs, were toluene, carbon disulfide, ethyl acetate and methyl sulfide, with the concentration ranging from 13.25 to 18.06 μg m−3. Finally, 11 main hazardous air pollutant VOCs, accounting for 32.77% of the TVOCs, were propylene, 2-butanone, toluene, methyl methacrylate, etc., with the concentration ranging from 81.05 to 116.96 μg m−3. Results could contribute to filling the knowledge gaps in the characteristics of VOC emissions from biogas digestate (BD), and provide a basis for exploring mitigation strategies on odor and hazardous air pollutions.

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