• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.34-39
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• 2005

Trichloroethylene (TCE) is an environmental contaminant provoking genetic mutation and damages to liver and central nerve system even at low concentrations. A practical scheme is reported using toluene as a primary substrate to revitalize the biofilter column for an extended period of TCE degradation. The rate of trichloroethylene (TCE) degradation by Pseudomonas putida F1 at $25^{\circ}C$ decreased exponentially with time, without toluene feeding to a biofilter column ($11\;cm\;I.D.{\times}95\;cm$ height). The rate of decrease was 2.5 times faster at a TCE concentration of $970\;{\mu}g/L$ compared to a TCE concentration of $110\;{\mu}g/L$. The TCE itself was not toxic to the cells, but the metabolic intermediates of the TCE degradation were apparently responsible for the decrease in the TCE degradation rate. A short-term (2 h) supply of toluene ($2,200\;{\mu}g/L$) at an empty bed residence time (EBRT) of 6.4 min recovered the relative column activity by $43\%$ when the TCE removal efficiency at the time of toluene feeding was $58\%$. The recovery of the TCE removal efficiency increased at higher incoming toluene concentrations and longer toluene supply durations according to the Monod type of kinetic expressions. A longer duration ($1.4{\sim}2.4$ times) of toluene supply increased the recovery of the TCE removal efficiency by $20\%$ for the same toluene load.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.8
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• pp.492-497
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• 2015

VOCs (Volatile Organic Compounds) are generally generated in the painting process, or at the company and laundry where use organic solvents. The VOCs consist of various hydrocarbons and has low calorific value due to its dilution with atmospheric air. Therefore, the VOCs are difficult to burn by a conventional fuel combustor. In this study, a novel plasma dump combustor was proposed for the treatment of low calorific VOC gases. This combustor was designed a combination of the characteristics in a plasma burner, a dump combustor and a 3D matrix burner. The combustor has good structure for maintaining enough residence time and reaction temperature for stable flame formation and VOC destruction. For investigating the performance characteristics of the plasma dump combustor, an experiment was achieved for VOC feed rate, VOC injector position, etc. Toluene was used as a surrogate of VOC. The novel combustor gave better performance than a conventional combustor, showing that VOC destruction rate and energy efficiency were 89.64% and 12.27 kg/kWh respectively, at feeding rate of 450 L/min of VOC of 3,000 ppm of toluene concentration.

• Journal of Environmental Science International
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• v.13 no.9
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• pp.767-777
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• 2004

This study evaluated the technical feasibility of the application of $TiO_2$ photocatalysis for the removal of volatile hydrocarbons(VHC) at low ppb concentrations commonly associated with non-occupational indoor air quality issues. A series of experiments was conducted to evaluate five parameters (relative humidity (RH), hydraulic diameter (HD), feeding type (FT) of VHC, photocatalytic oxidation (PCO) reactor material (RM), and inlet port size (IPS) of PCO reactor) for the PCO destruction efficiencies of the selected target VHC. None of the target VHC presented significant dependence on the RH, which are inconsistent with a certain previous study that reported that under conditions of low humidity and a ppm toluene inlet level, there was a drop in the PCO efficiency with decreasing humidity. However, it is noted that the four parameters (HD, RM, FT and IPS) should be considered for better VHC removal efficiencies for the application of $TiO_2$ photocatalytic technology for cleansing non-occupational indoor air. The PCO destruction of VHC at concentrations associated with non-occupational indoor air quality issues can be up to nearly 100%. The amount of CO generated during PCO were a negligible addition to the indoor CO levels. These abilities can make the PCO reactor an important tool in the effort to improve non-occupational indoor air quality.

• Korean Journal of Poultry Science
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• v.13 no.2
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• pp.221-226
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• 1986

In order to study the effect of feeding moldy corn in the feed and to compare the efficacy of several antidotical treatments, a feeding trial was conducted using broiler chickens. Ground yet low corn was adjusted to contain 20% moisture and then incubated at 35$^{\circ}C$ for 20 days. The number of fungi increased from 11${\times}$10$^4$/g to 42 10$\^$7/g on incubation but aflatoxins (B$_1$, B$_2$, G$_1$, G$_2$) were not detected by TLC test. Moldy corn was included in the experimental diets at the level of 7% with various treatments. Thirty six hatched male broiler chickens were divided into 6 groups and each group was placed for 4 weeks on one of the following treatments: Fresh corn, Moldy corn, Ammoniated (1.5%) moldy corn, Moldy corn＋BHT (0.1%), Moldy corn CTC (100ppm) and Moldy corn＋Probiotics. Weight gains of the birds fed Ammoniated moldy corn diet, Moldy corn＋Probiotics dist and Moldy corn＋CTC diet were greater by 6.1%. 7.6% and 3.9% respectively than those fed Moldy corn diet. The feed efficiencies of Moldy corn＋Probiotics diet and Moldy corn＋CTC diet were better than those of Moldy corn diet. Dry matter contents of the livers of the birds fed Ammoniated moldy corn diet, Moldy corn＋BHT diet and Moldy corn diet were lower than those of other treatments. Proteion contents of the livers of the birds fed Moldy corn diet, Moldy corn ＋CTC diet and Moldy corn＋BHT diet were lower than those of other treatments. Moldy corn tended to increase fat content of the livers.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.535-539
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• 2008

Conversion to oil, yield of styrene and formation of side products such as ${\alpha}-methyl$ styrene, ethyl benzene, benzene, toluene, dimer and trimer were affected by residue formed during thermal degradation. Also, control of reaction temperature had a difficulty at the first stage. Thus, new reaction system using wetted-wall type reactor was proposed and examined on various parameters such as reaction temperature, feeding rate and removal velocity of formed vapor. Optimun condition was obtained from continuous thermal degradation using wetted-wall type reactor and reaction kinetic study was carried out at new type reactor.