• Korean Journal of Environmental Agriculture
• /
• v.12 no.1
• /
• pp.9-17
• /
• 1993

The leaching behavior of $^{14}C-carbofuran$, $^{14}C-bentazon$, and $^{14}C-3,3,4,4'-tetrachloroazobenzene(TCAB)$ in the forms of freshly treated, 3-month-aged, and 6-month-aged residues, respectively, was investigated in a loamy soil column system. The degradation and mobility of pesticides in soil and the possibility of the contamination of groundwater were followed by this approach: The ambient temperature of $15{\pm}2^{\circ}C$, irrigation by the constant-head method on soil columns, and leaching with 1332 ml of simulated precipitation during 90 days. While the fresh residues of $^{14}C-carbofuran$ and $^{14}C-bentazon$ were very mobile, the aged ones were remarkably reduced in their mobility. Fresh and aged residues of $^{14}C-TCAB$ were very immobile, instead. 3-Keto carbofuran phenol(2,3-dihydro-2,2-dimethyl-3-oxo-7-benzofuranol) was the major degradation product present in the leachate from the soil column containing freshly treated $^{14}C-carbofuran$, while no metabolites could be detected in the leachates from the columns containing $^{14}C-bentazon$ or $^{14}C-TCAB$.

• The Journal of Engineering Geology
• /
• v.17 no.1 s.50
• /
• pp.125-133
• /
• 2007

The environmental and geotechnical properties are investigated to the 8th landfill area made of only sewage sludge in Nanji-Do. To do this, the soils are sampled in this area, and leaching tests, heavy metal content tests, and so on are performed to research the environmental properties. As the result of heavy metal content tests, Pb, Zn, Cu, Ni, Cd and Cr were leached from the sewage sludge. Because the leaching concentration of Cu is more than the standard value of California state, Cu content have to bring down during the recycling of the sewage sludge. Meanwhile, a series of tests concerning specific gravity, liquid and plastic limits, compaction, permeability and shear strength is performed to research the geotechnical properties. The sewage sludge is consisted of sand, silt and clay, and is classified into non-organic silt or organic clay with 42.3% of plastic index. As the result of compaction test, it is expected that the compaction effect according to variation of water contents is low relatively because the dry unit weight is low and the curve of compaction forms flatness. Also, as the result of direct shear tests, the cohesion is $0.058kg/cm^2$, and the internal friction angle is $14^{\circ}$. Taking everything into consideration, the various problems are happening in case of recycling the sludge like the cover layer of landfill and so on because the compaction is bad, and the shear strength is low. Also, it is expected that the ground water pollution caused by leaching the heavy metal into the sludge. To do recycling the sewage sludge in this site, supplementary and treatment programs should be prepared.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.26 no.2
• /
• pp.63-68
• /
• 2006

This experiment was carried out to investigate the availability of swine slurry on mixed grassland pasture. Three types of fertilizer was used, chemical fertilization($N-P_2O_5-K_2O=210-150-180kg/ha$), no fertilization and swine slurry was further subdivide into three groups (100%, 150%, 200%) as compared to the level of N used in the chemical fertilizer. The results showed that dry mater yield of forage was increased with increasing application level of swine slurry. Production of dry matter of swine slurry 200% was similar to that of chemical fertilizer, but percentage of legume in mixed pasture was lower in chemical fertilization. Percentage of legume was increased with increasing application level of swine slurry. Level of $NO_3-N$ in filtered water was very low in all groups applied with swine slurry. Based on this results the optimum level of swine slurry application is 200% of the normal standard of N fertilizer used in grassland pasture.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.10 no.3
• /
• pp.161-170
• /
• 2012

To provide domestic values of input parameters in a safety assessment of radioactive waste disposal under domestic deep underground environments, various kinds of experiments have been carried out under KURT (KAERI Underground Research Tunnel) conditions. The input parameters were classified, and some of them were selected for this study by the criteria of importance. The domestic experimental data under KURT environments were given top priority in the data review process. Foreign data under similar conditions to KURT were also gathered. The collected data were arranged and the statistical calculations were processed. The properties and distribution of the data were explained and compared to foreign values in view of their validity. The following parameters were analysed: failure time and early time failure rate of a container, solubility of nuclides, porosity and density of the buffer, and distribution coefficients of nuclides in the geomedia, hydraulic conductivity, diffusion depth of nuclides, groundwater flow rate, fracture aperture, length of internal fracture, and width of faulted rock mass in the host rock.

• Analytical Science and Technology
• /
• v.31 no.5
• /
• pp.185-194
• /
• 2018

At the end of November 2010, livestock infected with foot and mouth disease (FMD) were buried, increasing concern about secondary pollution of drinking water and groundwater with odor. Hence, measures to reduce pollution of drinking water and groundwater are needed. In this study, based on livestock type and soil texture, five pilot-scale burial sites were monitored for the past three years from Feb 2012 to 2015. Leachate from the site was analyzed for 90 compounds. A detailed investigation has been completed, looking into organic matter decomposition characteristics of the buried bodies, relevant trace elements thereof, and in particular metabolite concentration changes such as the degree of decomposition of a carcass. From the results, no detectable heavy metals, including cadmium and arsenic, were measured. Among animal types, the rate of cattle decomposition is faster than swine decomposition, and the decomposition of the bodies were performed in sequence from sand, clay loam, sandy loam.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.4
• /
• pp.281-288
• /
• 2011

Recently, researches that a variety of contaminants in water are removed by sonolysis technology with oxidation and pyrolysis process from cavitation were conducted. However, there are few studies for sonochemical treatment by a pilot-scale ultrasound system. This research focused on developing pilot-scale ultrasound systems, which could be an continuously effective treatment for a large volumes of contaminants, and demonstrating the feasibility of utilizing these systems to remove naphthalene from groundwater. V-120 type reactor was found to be 1.4~2.2 times higher effective than the normal type. A total of three different pilot scale's systems consisted of installing effluent and irrigation water in order to be a continuos system, including supplemental additives, and applying a V-120 type reactor and a external cooling cycle system. Naphthalene levels treated by three systems were lower than a recommended guideline of naphthalene for drinking water in EPA. Especially, the naphthalene removal efficiencies of PS1 and PS2 systems were over 97%. The pilot-scale continuous ultrasound clean-up system delivered over 84~95% naphthalene removal efficiency for treatment of 10~20 liter of groundwater. In addition, the ultrasound system could be successfully applied to the conditions of artificial and genuine groundwater contaminated with naphthalene.

• Journal of the Korean earth science society
• /
• v.28 no.1
• /
• pp.112-122
• /
• 2007

It is known that coal-derived fly ashes have the unique chemical composition and mineralogical characteristics. Since iron oxides in coal fly ash are enriched with heavy metals, the subsurface media including soils, underground water, and sea water are highly likely contaminated with heavy metals when the heavy metals are leached from fly ashes by water-fly ash interactions. The purpose of this study was to investigate how indigenous bacteria affect heavy metal leaching and mineralogy in fly ash slurry during the fly ash-seawater interactions in the ash pond located in Dangjin seashore, Korea. The average pH of ash pond seawater was 8.97 in nature. Geochemical data showed that microbial activity sharply increased after the 7th day of the 60-day course batch experiments. Compared with other samples including autoclaved and natural samples, ${SO_4}^{2-}$ was likely to decrease considerably in the fly ash slurry samples when glucose was added to stimulate the microbial activity. Geochemical data including Eh/pH, alkalinity, and major and trace elements showed that the bacteria not only immobilize metals from the ash pond by facilitating the chemical reaction with Mn, Fe, and Zn but may also be able to play an important role in sequestration of carbon dioxide by carbonate mineral precipitation.

• Geophysics and Geophysical Exploration
• /
• v.19 no.1
• /
• pp.37-44
• /
• 2016

$CO_2$-EOR (Carbon Dioxide-Enhanced Oil Recovery), one of the enhanced oil recovery methods, helps to not only enhance the production of oil, but also store carbon dioxide in underground. However, if micro fractures occur when during the injection of $CO_2$, it is difficult to make permanent storage of $CO_2$ in reservoir and can cause contamination of groundwater and soil. Therefore, in this study, we performed microseismic monitoring to investigate the occurrence of fractures during the $CO_2$ injection at the Meruap oil reservoir, Indonesia. To pick the first arrivals of microseismic events, Improved MER (Modified Energy Ratio) method was used. After picking the first arrivals, hodogram analysis was carried out by using the data recorded at three component geophones to calculate the back azimuth of events. Finally, locations of microseismic events were decided by using the results of first arrival picking and hodogram analysis. Estimated locations showed that all microseismic events were occurred at surface and any fracture did not occur around the reservoir. Moreover, by analyzing noise characteristic, we confirmed that almost of picked first arrivals were due to the repetitive mechanical noise.

• Journal of Korea Water Resources Association
• /
• v.51 no.6
• /
• pp.515-521
• /
• 2018

Seawater intrusion areas were calculated in Yeosu region considering sea level rise and the effects of countermeasures for seawater intrusion were analyzed using SEAWAT program. The estimated seawater intrusion area was $14.90km^2$ in 2015. When we applied climate change scenarios the area was changed to $19.19km^2$ for RCP 4.5 and $20.43km^2$ for RCP 8.5 respectively. The mitigation effects by artificial recharge with total $50m^3/d$, $100m^3/d$, and $300m^3/d$ are from 3.75% to 10.68% for RCP 4.5, and from 5.82% to 10.77% for RCP 8.5 respectively. If we install barrier wall with the thickness 0.8 m, 1.3 m, and 1.8 m, the mitigation effects are from 6.67% to 12.04% for RCP 4.5, and from 6.17% to 14.98% for RCP 8.5 respectively. The results of this study can be used to be a logical means of quantitative grounds for policy decisions to prevent groundwater contamination by seawater intrusion and subsequent secondary damage in coastal areas.

• Membrane Journal
• /
• v.18 no.1
• /
• pp.7-25
• /
• 2008

Sodium dodecyl sulfate, which was anionic surfactant, at a concentration higher than its critical micellar concentration was added to calcium solution for forming micelles. Then aggregates were formed by adsorption or binding of calcium ions on the surface of micelles, and gathering between them, and then rejected by two kinds of ceramic membranes to remove calcium ions. As result, rejection rates of calcium were higher than 99.98%. And in our experimental range the higher TMP trended to increase the resistance of membrane fouling ($R_f$), total permeate volume ($V_T$), dimensionless permeate flux ($J/J_o$) and permeate flux (J) because TMP was driving force. And we investigated effects of $N_2$-back-flushing time and filtration time, that was back-flushing period, during periodic $N_2$-back-flushing on ceramic membranes. As result, optimal BTs for NCMT-623l ($0.07{\mu}m$ pore size) and NCMT-7231 membrane ($0.10{\mu}m$) were 10 sec and 15 sec, respectively. Also, optimal FT was 5 min for both membranes, and the frequent $N_2$-back-flushing could decrease membrane fouling effectively. Then, the optimal conditions resulting from our experiments for synthetic calcium solution were applied to groundwater using as washing process of soymilk package. As result, rejection rates of calcium were higher than 99.98%.