• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.143-157
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• 2002

Batch and column tests were conducted with common groundwater contaminants (i.e., trichloroethylene) to determine transport parameters and reactivity of the foundry sands. The reactivities of foundry sands for common groundwater contaminants are comparable to or slightly higher than those for Peerless iron a common medium used in permeable reactive barriers. In addition, the TOC and clay in foundry sands can significantly retard the movement of target contaminants, which may result in lower effluent concentrations of contaminants due to biodegradation. In general, permeable reactive barriers with the thickness of 1m can be constructed with many foundry sands to treat typical groundwater comtaminants provided the zero-valent iron content in the foundry sand is higher than 1%.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.51-59
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• 1996

The purpose of this study was to evaluate the partial oxidation of the biological treatment plant effluents using Fenton's reagent as a pretreatment step prior to a tertiary biological oxidation of these effluents. Fenton's reagent was evaluated as a pretreatment process for inhibitory or refractory organics. Based on the Fenton oxidation system, the petrochemical wastewater treatment plant effluent was shown to have significant improvement in toxicity after oxidation with hydrogen peroxide. For example, at ranee of 42 ∼ 184 mg/L COD of petrochemical plant effluents, the COD removal efficiencies were from 38.2% to 60.1% after reaction with hydrogen peroxide 200 mg/L and Fe2+ 100 mg/L and reaction time was 30 minutes. The total TOC reduction were about 15.8∼22.4% with same test condition and difference between the overall removal rate and BOD/COD ratio after Fenton's oxidation estabilished in the biodegradation and otherwise meets the discharge standard or reuse for cooling tower make-up water.

• Preventive Nutrition and Food Science
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• v.3 no.1
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• pp.27-35
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• 1998

Starch-polyethylene films containing high molecular weight(NW) oxidized-polyethylene and prooxidant were prepared , and thermal -and bio-degradability of the films were determined. Increased levels of starch resulted in a corresponding reduction in mechanical strength of the films. However, the addition of high MW oxidized-polyethylene did not significantly reduce the percent elongation of the films. Thefilms containing high MW oxidized-polyethylene andproosicant were degreaded faster than those containing no aadditive during the heat treatment. The films lost their measureable mechanical properties when their weight-average MW(Mw) fell below 50,000. Biodegradability of the films was determined by a pure culture assay with either Streptomyces badius 252.S. setonii 75Vi2 or S. viridosporous T7A, and by an extracellulr enzyme assay using S. setonii 75vi2. The results from pure culture assay indicated that biomass accumulation on the film surface inhibited chemical and biological degradation of the films. The extracellular enzyme assay demonstrated decrease of percent elongation and increase of carbonyl index of the films. Therefore, extracellular enzyme assay could be used as a good method to evaluate biodegradability of the films.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.92-99
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• 2001

This present study was aimed to investigate the characteristics of dissoloved organic matter (DOC) in sewage. The results are summarized as follows ; The plateaux reached in 3~4 days by the biodegradability test on sewage samples based on DOC. 쏭 rations of BDOC to DOC were 48, 21, 13 and 11% for raw sewage, primary treatment effluent, secondary treatment effluent and final treatment effluent, respectively. As the SUVA values ranged less 3L/m.mg for the effluent of sewage treatment plant, the DOC is composed largely of non-humic materials, hydrophilic, less aromatic as compared to waters with higher SUVA values. Through the biodegradability test, Dissolved organics showed that the quantity of LMW(Low Molecular Weight) less than 1,000 daltons was decreased, HMW(High Molecular Weight) more than 30,000 daltons had a tendency to increase. Large portion of UV$^{254}$ in final treatment effluent was increased of MMW(Medium Molecular Weight). Also, average removal efficiency of DOC was 32% during sewage treatment.

• Journal of Microbiology and Biotechnology
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• v.16 no.4
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• pp.605-612
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• 2006

A psychrotrophic bacterium was isolated from oil-contaminated groundwater and identified as Rhodococcus sp. YHLT-2. Growth was observed at the temperature of 4 to $30^{\circ}C$. This strain degraded various petroleum hydrocarbons such as crude oil, diesel oil, and gasoline over the whole range of temperatures tested. The Rhodococcus sp. YHLT-2 was capable of growing even at $4^{\circ}C$, exhibiting 90% of oil biodegradation after 20 days. Degradation of crude oil occurred at low temperature in nature. This strain was also able to grow at 7% NaCl, and utilized not only short chain alkenes $(C_9\;to\;C_{12})$, but also a broad range of long chain alkenes $(C_{19}\;to\;C_{32})$ present in crude oil at $4^{\circ}C$. The Rhodococcus sp. YHLT-2 is expected to be of potential use in the in situ bioremediation of hazardous hydrocarbons under low-temperature and high-salt conditions.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.73-76
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• 2000

A novel, continuous bioreactor system combining a bubble column (absorption section) and a two-phase bioreactor (degradation section) has been designed to treat a gas stream containing benzene. The bubble column contained hexadecane as an absorbent for benzene, and was systemically chosen considering physical, biological, environmental, operational and economic factors. This solvent has infinite solubility for benzene and very low volatility. After absorbing benzene in the bubble column, the hexadecane served as the organic phase of the two-phase partitioning bioreactor, transferring benzene into the aqueous phase where it was degraded by Alcaligenes xylosoxidans Y234. The hexadecane was then continuously recirculated back to the absorber section for the removal of additional benzene. All mass transfer and biodegradation characteristics in this system were investigated prior to operation of the integrated unit, and these included: the mass transfer rate of benzene in the absorption column, the mass transfer rate of benzene from the organic phase into the aqueous phase in the two-phase bioreactor, the stripping rate of benzene out of the two-phase bioreactor, etc. All of these parameters were incorporated into model equations, which were used to investigate the effects of operating conditions on the performance of the system. Several experiments were conducted to show the feasibility of this system. This process is believed to be very practical for the treatment of high concentrations of gaseous pollutants.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.243-250
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• 2003

Eight numerically dominant 4-(2,4-dichlorophenoxy) butyric acid (2,4-DB)-degrading bacteria and three pairs of bacteria showing syntrophic metabolism of 2,4-DB were isolated from soils, and their phylogenetic and phenotypic characteristics were investigated. The isolates were able to utilize 2,4-DB as a sole source of carbon and energy, and their 2.4-DB degradative enzymes were induced by the presence of 2.4-DB. Analysis of 16S rDNA sequences indicated that the isolates were related to members of the genera, Variovorax, Sphingomonas, Bradyrhizobium, and Pseudomonas. The chromosomal DNA patterns of the isolates obtained by polymerase-chain-reaction (PCR) amplification of repetitive extragenic palindromic (REP) sequences were distinct from each other. Four of the isolates had plasmids, but only one strain, DB 1, rad a transmissible 2,4-D degradative plasmid. When analyzed with PCR using primers targeted to the tfdA, B, and C genes, only strains DB2 and DB9a produced DNA bands of the expected sizes with the tfdA and C primers, respectively. All of the isolates were able to degrade 2,4-D as well as 2,4-DB, suggesting that the degradation pathways of these compounds were closely related to each other, but respiratory activities of many isolates adapted to 2,4-DB metabolism were quite low with 2,4-D.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.239-243
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• 2012

Degradation of butylbenzyl phthalate (BBP) by the white rot fungus Pleurotus ostreatus and the activities of some degrading enzymes were examined in two different media containing 100 mg/l of the compound. P. ostreatus pre-grown for 7 days in complex YMG medium was able to completely degrade BBP within an additional 24 h but degraded only 35 mg/l of BBP in 5 days of incubation in minimal medium. Fungal cell mass in the culture in YMG medium was higher in the presence than in the absence of BBP. The esterase activity of the fungal culture in YMG medium was higher than that in minimal medium and increased with the addition of BBP. On the contrary, laccase activity was higher in minimal medium and it did not increase upon the addition of BBP. General peroxidase activity increased for a few days after the addition of BBP to both media. The degradation of BBP and its metabolites by P. ostreatus thus may be attributed mostly to esterase rather than lignin-degrading laccase. In addition, the activities of the enzymes involved in BBP degradation and their changes varied significantly in the different media and culture conditions.

• Environmental Engineering Research
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• v.23 no.3
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• pp.271-281
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• 2018

To examine the feasibility of reuse of raw fishmeal wastewater, it was biodegraded by a microbial consortium in a $1-m^3$ reactor, and the final culture broth including mixed microbes was applied as biofertilizer to field cultivation of lettuce and Chinese cabbage. Moreover, economic analysis of the entire process was performed. A stable metabolism of organic matter degradation for 80 h with sufficient dissolved oxygen produced an amino acid content of 14.66 g per 100 g sample, along with increased cation and anion concentrations. The concentrations of N, P and K in the final culture broth were 2.26, 0.87 and 0.65%, respectively, while those of heavy metals were very low. In field cultivation of the two leafy vegetables, the biodegraded fishmeal wastewater showed better fertilizing ability than commercial fertilizers because of its high amino acid content. In addition, no external damage to leaves by the fertilization was observed. In economic analysis, the expected profitability from the practical reuse of raw fishmeal wastewater was estimated to be $491.68 per a single biodegradation, which corresponds to $25,567.36 per year. As a result, the complete reuse of fishmeal wastewater could be feasible and provide essential benefits.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.400-404
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• 2004

Polycaprolactone (PCL), a synthetic aliphatic polyester, was buried in activated sludge soil for 66 days at $27^\circ{C}$ and $37^\circ{C}$. The morphology of the surface of PCL film degraded by soil microorganisms was observed. Soil microorganisms degrading PCL were isolated and identified. Soil fungi and soil bacteria utilizing PCL as carbon or energy source were identified as Paecilomyces fumosoroseus KH27, Penicillium digitatum KH28, Fusarium solani KH29, Aspergillus sp. KH30 and Ochrobactrum anthropi KH31, respectively. Biodegradation test of PCL by the isolated strains showed that, P. digitatum KH28 exhibited the most PCL degrading activity at $27^\circ{C}$. However, at $37^\circ{C}$ O. anthropi KH31 showed higher degrading activity than the other soil microorganisms tested.