• Journal of Korean Society on Water Environment
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• v.27 no.4
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• pp.397-404
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• 2011

This research investigates the runoff characteristics of refractory organic matters from Kyongan river watershed. Samples were taken 27 times during dry season, 4 times during rain events and analyzed into flow rate, Dissolved Organic Carbon (DOC), Particulate Organic Carbon (POC), Refractory Dissolved Organic Carbon (R-DOC), Refractory Particulate Organic Carbon (R-POC). R-DOC during dry season was the lowest in winter and showed a rising tendency in spring and R-POC changes less than R-DOC. The mass loading of Refractory Total Organic Carbon (R-TOC) in summer takes approximately 80% of 1 year mass loading. During rainy season, EMC of R-DOC was similar to R-DOC in dry season. But maximum EMC of R-POC was 12 times higher than that of R-POC in dry season. Results of the survey show that enhanced management of R-DOC in dry season and R-POC in rainy season is needed.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.10
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• pp.575-580
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• 2017

Chlorinated hydrocarbons (TCE and PCE), petroleum hydrocarbons (BTEX, PAHs, and TPH), and explosive compounds (TNT, RDX, and HMX) have been detected in underground water countrywide. The overall objective of this study is to evaluate sono-catalytic degradation coupled with the use of PUV in order to understand the fate and transport of a representative selection of non-biodegradable contaminants (i.e., TCE, PCE, BTEX, PAHs, TPH, TNT, RDX, and HMX) in groundwater. Both ultraviolet (UV) and ultrasound (US) systems are used in degrading of organic contaminants and they can thus be applicable simultaneously as an UV/US hybrid system in attempts further to increase the degradation efficiency. Results indicate that synergistic effect of UV/US hybrid system is closely correlated to the enhancement of sono-chemical reactivity with the UV-US interaction of increasing the formation rate of OH by providing additional $H_2O_2$ production through the pyrolysis of water molecules during UV/US hybrid irradiation.

• Korean Journal of Environmental Agriculture
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• v.20 no.2
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• pp.79-85
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• 2001

From July to November 1999, air samples were collected from Ansung, Korea, to identify the seasonal variation in organochlorine pesticides(OCPs). OCPs maximum(mean) concentrations were as follows: heptachlor, $14.0\;pg/m^3(3.6\;pg/m^3)$; heptachlor epoxide, $28.7\;pg/m^3(11.7\;pg/m^3)$; DDE, $40.6\;pg/m^3(20.6\;pg/m^3)$; endosulfan sulfate, $98.9\;pg/m^3(36.6\;pg/m^3)$. The higher concentration of the locally and seasonally used pesticide endosulfan[1759.2 $pg/m^3(453.4\;pg/m^3)$] was found. The concentrations of all OCPs were higher in summer than those in fall. This pattern suggests that the concentrations may be increased by evaporation from surfaces(soil, water, vegetation, etc) with increasing the temperature and by much usage in growing season, particularly in summer, for endosulfan.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.76-83
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• 2000

This research is about wastewater containing non-biodegradable TDI(Toluene Diisocyanate) that is treated by the activated carbon adsorption method. In the case of the Fenton oxidation process being applied to the existing process, optimal pH, reaction time, chemical dosing amount, removal rate, and cost were investigated. A pilot plant test was applied after finding optimal conditions with lab experiments. The optimal conditions were pH 3~5(COD removal rate 84~88%) and reaction time 30min~1hr. In higher $H_2O_2$ dosing amount, COD removal rate was a little higher. But there was little difference in the removal rate according to $FeSO_4{\cdot}7H_2O$ dosing amount. Treatment cost was economical in the case of the Fenton oxidation process being operated earlier than activated carbon adsorption system. But chemical dosing point, chemical mixing effect, chemical dosing amount, removal rate, and the cost of facility and others must be considered in practical process.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.301-306
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• 2009

This research was carried out to establish the effective treatment condition and characteristic of wastewater from the electroplating plant of cold rolling mill by using microorganism. Alkaline wastewater and acidic heavy metal wastewater accounted for 64%, 30%, respectively, of the total wastewater. Highly concentrated thiocyanate was 53890 mg/L as COD and it was 53% of total COD, even though it was 0.03% of wastewater from the electroplating plant. When treating mixed wastewater with microorganism, it was easy to remove when SCN concentrations of mixed wastewater was 200 mg/L or less. While the treatment effect of COD-causing materials was low at the concentration of 400 mg/L or less, it implies that highly concentrated thiocyanate contains a large amount of slowly biodegradable organics. When treating with mixed wastewater, pH was 7.33 at the beginning, but after 8 hours it increased to 7.99. This is caused by ammonia which is generated when SCN of highly concentrated thiocyanate was degraded by microorganism.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.5-12
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• 2017

Effects of operating parameters such as activated carbon dose, gaseous $O_3$ concentration and pH on the properties of methylene blue(MB) degradation in a catalytic ozonation were investigated through a series of batch experiments. Activated carbon catalyzed the self-decomposition of ozone, generating $OH{\cdot}$, thus promoting MB degradation. Thus the increase of activated carbon dose enhanced the MB and TOC removal. The higher gaseous ozone concentration injected, the promoted MB and TOC removal obtained through the enhanced mass transfer. The MB removal was not significantly affected by the variation of aqueous pH. Catalytic ozonation can be considered as an efficient alternative in treating refractory pollutants in textile wastewater with faster and higher dye and TOC removal compared with ozonation and adsorption.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.93-95
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• 2010

White rot fungi which have lignin degrading enzymes show high degrading activity to diverse recalcitrant compounds such as polycyclic aromatic compounds, dyes, explosives and endocrine disrupting chemicals. We have examined decolorizing activity of dyes by Phlebia tremellosa and two transformants which had genetically transformed using laccase or manganese peroxidase (MnP) gene. In case of methyl green, wild type strain showed 50% decolorization while laccase transformant (TF2-1) and MnP transformant (T5) showed more than 90% decolorization on day 3. Remazol brilliant blue R(RBBR) was decolorized up to 85% by two transformants while the wild type showed 67% decolorization on day 3. Transformants TF2-1 and T5 both showed increased laccase and MnP activity respectively during the whole growing phase.

• Korean Journal of Microbiology
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• v.44 no.3
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• pp.199-202
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• 2008

A white rot fungus Irpex lacteus produced lignin degrading enzymes, which showed degrading activity against various recalcitrant compounds. However, laccase, one of the lignin degrading enzymes, was too low to be assayed by spectrophotometry using o-tolidine as the chromogenic substrate in this fungus under various culture conditions. A laccase expression vector was constructed using a cDNA from Phlebia tremellosa with the constitutively expressed promoter of glyceraldehydes-3-phosphate dehydrogenase gene, and introduced into I. lacteus by the restriction enzyme mediated integration transformation through the protoplast-$CaCl_2$ procedure. Two transformants showed highly increased laccase activities at the early growth phase in the minimal liquid medium, and they not only degraded bisphenol A, a notorious endocrine disrupting chemical, but also removed the estrogenic activity effectively.

• Membrane Journal
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• v.12 no.1
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• pp.21-27
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• 2002

The formation of soluble microbial products(SMP) and molecular weight distribution on loading rate were observed in batch-type culture medium, which phenol was fed as a substrate. The molecular weight destribution was obtained by using 30K, 100K dalton and $0.45{\mu}$ membrane filters. When the phenol concentrationas a substrate was 120, 230 and 440 mg/L , the specific substrate utilization rate(q) showed 0.639, 1.281 and 1.744 mgTOC/mgMLSS/day, respectively. The endogenous biomass decay rate constant($K_d$) at each substrate concentration was 0.00536, 0.0661 and 0.0749($day^1$), respectively. The $SMP_e$ product rate constant($k_{SMP}_ e$) showed 0.006, 0.0058 and 0.0057($day^1$), respectively. The initial influent substrate during the course of time degraded and produced $SMP_s$. The $SMP_s$ was converted to the $SMP_{nd}$ and endogenous phase converted to the $SMP_e$ ingredients. The molecula weight distribution on loading rate was converted to a higher MW during the course of time.

• Clean Technology
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• v.29 no.1
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• pp.1-9
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• 2023

Waste explosives such as useless ammunition discharged from the military and coproduced useless explosives during the manufacturers production process have been continuously produced. These are difficult to dispose with normal waste treatment facilities due to the dangers of fire and explosion. An open burning or an open detonation at military designated disposal facilities is a classical treatment method for the dangerous explosives. The classical method raises various environmental problems by the emission of hazardous materials. An air pollution by the emission of hazardous gases such as SO_x and NO_x, soil and water contaminations by the accumulation of non-biodegradable heavy metals, are representative pollution examples. To overcome these problems, various processes for eco-friendly waste treatment methods have been developed, and some processes have already been operated in some countries. In the current report, various eco-friendly disposal processes for waste explosives or harmful materials, and their advantages and disadvantages are documented to suggest future development directions for reducing the hazardous substances by the treatment processes.