• Journal of Bio-Environment Control
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• v.13 no.4
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• pp.233-239
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• 2004

This research was conducted to determine the effect of soil pH change followed by leaching with ground water on crop growth, yield and nutrient uptake of strawberry. Treatments were leaching with ground water (A), hydrated lime application of dissolved portion in $500g{\cdot}L^{-1}$ solution followed by leaching (B), application of $Al_2SO_4$ solution with the concentration of $0.75g{\cdot}L^{-1}$ followed by leaching (C), pH elevation by (B) followed by pH lowering by (C), then leaching (D). Soil samples taken before experiment had 6.0 in soil pH. But the pH of all treatments taken after pH changes and leaching were in the range from 5.8 to 6.2 without statistical differences among treatments. Electrical conductivity of soils taken before experiment was $1.82dS{\cdot}m^{-1}$ and those of (A), (B), (C), and (D) were 1.65, 1.72, 1.71 and $1.83dS{\cdot}m^{-1}$, respectively. The plant height in treatment (C) was 20.4 cm at 80 days after transplanting which was the highest among treatments tested. The other growth characteristics did not show statistical differences among treatments. Tissue contents of Fe, Mn, Zn, Cu and B in treatment (C) were higher than those of other treatments at 80 days after transplanting. The treatment (C) had the highest number of special sizes and fruit weight per 50 plants such as 137 and 3.784 g, respectively. The treatment also had 3.123 kg in total fruit weight and 2,489 kg in marketable fruit weight per 10 are. The treatment (B) also had good results such as 2,820 kg in marketable fruit weight per 10 are.

• Economic and Environmental Geology
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• v.38 no.5 s.174
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• pp.547-561
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• 2005

General characteristics of groundwater contamination by As were reviewed with several recent researches, and its occurrence in groundwater of Korea was investigated based on a ffw previous studies and a groundwater quality survey in Nonsan and Geumsan areas. In Bangladesh, which has been known as the most serious arsenic calamity country, about $28\%$ of the shallow groundwaters exceeded the Bangladesh drinking water standard, $50{\mu}g/L$, and it was estimated that about 28 million people were exposed to concentrations greater than the standard. Groundwater was characterized by circum-neutral pH with a moderate to strong reducing conditions. Low concentrations of $SO_4^{2-}$ and $NO_3^-$, and high contents of dissolved organic carbon (DOC) and $NH_4^+$ were typical chemical characteristics. Total As concentrations were enriched in the Holocene alluvial aquifers with a dominance of As(III) species. It was generally agreed that reductive dissolution of Fe oxyhydroxides was the main mechanism for the release of As into groundwater coupling with the presence of organic matters and microbial activities as principal factors. A new model has also been suggested to explain how arsenic can naturally contaminate groundwaters far from the ultimate source with transport of As by active tectonic uplift and glaciatiion during Pleistocene, chemical weathering and deposition, and microbial reaction processes. In Korea, it has not been reported to be so serious As contamination, and from the national groundwater quality monitoring survey, only about $1\%$ of grounwaters have concentrations higher than $10{\mu}g/:L.$ However, it was revealed that $19.3\%$ of mineral waters, and $7\%$ of tube-well waters from Nonsan and Geumsan areas contained As concentrations above $10{\mu}g/:L.$. Also, percentages exceeding this value during detailed groundwater quality surveys were $36\%\;and\;22\%$ from Jeonnam and Ulsan areas, respectively, indicating As enrichment possibly by geological factors and local mineralization. Further systematic researches need to proceed in areas potential to As contamination such as mineralized, metasedimentary rock-based, alluvial, and acid sulfate soil areas. Prior to that, it is required to understand various geochemical and microbial processes, and groundwater flow characteristics affecting the behavior of As.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.23-33
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• 2016

The characteristics of ammonia generated from alkaline stabilization facilities was investigated which are for organic sewage sludge from wastewater treatment plants. The highest concentration of ammonia was found in mixing and curing process in alkaline stabilization facility and ammonia mainly showed a range of 87.78 ppm($66.62mg/m^3$) to 1,933 ppm($1,467.01mg/m^3$) by detection tube. This is presumed to occur because nitrogen oxides are converted into ammonia as the sewage sludge is mixed with lime. In some facilities, hydrogen sulfide and methyl mercaptan were detected in relatively high concentrations, but odor materials except ammonia were not detected in most of the facilities. The concentration of ammonia caused by process was generally high in the order of "mixing > curing > output > storage > drying > input." It was found that odor compounds are removed by wet absorption using sulfuric acid and sodium hypochlorite in the 5 alkaline stabilization facilities currently in operation. Each facility was designed to meet the concentration of after-treatment emission in 1 ppm($0.76mg/m^3$), 50 ppm($37.95mg/m^3$) or 100 ppm($75.89mg/m^3$), but no facility satisfied the design standard for their emssion limit. In case of ammonia, some workplaces in alkaline stabilization facilities exceeded the exposure limits established by the Ministry of Labor. It appears that proper ventilation should be provided for the safety of workers in future. No odor compound including ammonia was found by detection tubes in the border of the facilities, but trace amounts of odor compounds are expected to exist, given the current operational status of facilities.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.428-433
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• 2013

Heterogenous samples of locust bean gum (galactomannan) were prepared into homogeneous substances. Locust bean gum was fractioned using ammonium sulfate (14.11-23.08%, w/w). The intrinsic viscosity was obtained by extrapolating reduced viscosity versus concentration by using an Ubbelohde viscometer. The ranges of intrinsic viscosity for fractions that not included protein (F3-F6) and fractions that included protein (F1-F2) were 9.89-8.10 and 8.44-4.59, respectively. Values for Huggins' coefficient (k'), which depends on physical interactions, were 0.46-0.78. Increasing ammonium sulfate concentration was associated with a weak trend towards lower molecular weight and intrinsic viscosity by size-exclusion chromatography (SEC): $M_w$ ranged from 674 to 617 kg/mol and [${\eta}$] from 9.80 to 8.10 dL/g between F3 and F6. The evaluations of those fractions by using SEC and the Ubbelohde viscometer produced very similar values, as predicted. We verified the application of a gradient of ammonium sulfate to precipitate locust bean gum into fractions of different molecular size and show structural variations.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.473-479
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• 2012

Water reuse has been highlighted as a representative alternative to solve the lacking water resource. This study carried out a study on the pipe corrosion and water quality change which can occur through the supply of reclaimed water, using a simulated reclaimed water distribution pipeline. Galvanized steel pipe (GSP), cast iron pipe (CIP), stainless steel pipe (STSP) and PVC pipe (PVCP) were used for the pipe materials. Reclaimed water(RW) and tap water(TW) were respectively supplied into simulated reclaimed water distribution pipelines. As a result of performing a loop test to supply reclaimed water to simulated reclaimed water distribution pipelines, the weight reduction of pipe coupons showed the sequence of CIP > GSP > STSP ${\approx}$ PVCP. In addition, reclaimed water showed a high corrosion rate comparing to that of tap water. In case of CIP, the initial corrosion rate showed 3.511 mdd(milligrams per square decimeter per day) for reclaimed water and 2.064 mdd for tap water and the corrosion rate for 90 days showed 0.833 mdd for reclaimed water and 0.294 mdd for tap water. Also in case of GSP, the initial corrosion rate showed 2.703 mdd for reclaimed water and 2.499 mdd for tap water and the corrosion rate for 90 days showed 0.349 mdd for reclaimed water and 0.248 mdd for tap water, which was a tendency similar to that appeared in CIP with a tendency to reduce the corrosion rate. As a result of water quality changes of reclaimed water at pipe materials to carry out the loop test, there was higher conversion ratio of ammonia into nitrate in CIP and GSP with higher corrosion rate than that in STSP and PVCP where no corrosion has occurred. The highest denitrification rate of nitrate could be observed from CIP with the most particles generated from corrosion. In CIP, it could be confirmed that there was MIC (Microbiologically Induced Corrosion) as a result of EDS (Energy Dispersive X-ray spectrometer System) analysis results.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.11
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• pp.1180-1185
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• 2006

Lab-scale batch experiments using several 25-L transparent acrylic reactors were conducted to develop optimum capping materials that can reduce phosphorus released from polluted sediments. The sediment used in the experiment was very fine clay(8.8 $\Phi$ in mean grain size), and organic carbon($C_{org}$) content was as high as 2%. Four kinds of batches with different capping materials Brucite($Mg(OH)_2$), Sea sand($SiO_2$), Granular-gypsum($CaSO_4{\cdot}2H_2O$), Double layer(brucite+sand), and one control batch were operated for 30 days. Phosphorus fluxes released from bottom sediments in the control batch were estimated to be 14.6 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, while 9.5 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 5.2 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, 4.2 $mg{\cdot}m^{-2}{\cdot}d^{-1}$, and 3.1 $mg{\cdot}m^{-2}{\cdot}d^{-1}$ in the batch capped with Sea sand, Granular-gypsum, Double layer, and Brucite, respectively. The results obtained from lab-scale batch experiments show that there were 70% reduction of phosphorus for some materials such as Brucite, Double layer(brucite+sand), and whereas sea sand only about 35%. The pH range of surface sediment to which Brucite was applied showed about $8.0{\sim}9.5$ in the weak alkaline state. This effect can prevent liberation of $H_2O$. The addition of gypsum into the sediment can reduce the progress of methanogenesis because of fast early diagenesis and sufficient supply of $SO_4^{2-}$ to the sediments, stimulate the SRB highly. Therefore, the application of Brucite and Gypsum can reduce phosphorus release from the sediment as a result of formation of $Mg_5(OH)(PO_4)_3$, pyrite($FeS_x$), and apatite-mineral.

• Economic and Environmental Geology
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• v.49 no.1
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• pp.13-22
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• 2016

The objectives of this study were to recover silica and iron oxides and $CO_2$ sequestration using serpentine via various acid dissolution and pH swing processes. Serpentine collected from Guhang-myeon in S. Korea were mainly composed of antigorite and magnetite consisting of $SiO_2$ (45.3 wt.%), MgO (41.3 wt.%), $Fe_2O_3$ (12.2 wt.%). Serpentine pulverized ($${\leq_-}75{\mu}m$$) and then dissolved in 3 different acids, HCl, $H_2SO_4$, $HNO_3$. Residues treated with acidic solution were recovered from the solution (step 1). And then the residual solution containing dissolved serpentine was titrated using $NH_4OH$. And pH of the solution increased up to pH=8.6 to obtain reddish precipitates (step 2). After recovery of the precipitates, the residual solution reacted with $CO_2$ and then pH increased up to pH=9.5 to precipitate white materials (step 3). The mineralogical characteristics of the original sample and harvested precipitates were examined by XRD, and TEM-EDS analyses. ICP-AES analysis was also used to investigate solution chemistry. The dissolved ions were Mg, Si, and Fe. The antigorite became noncrystralline silica after acid treatment (step 1). The precipitate at pH=8.6 was mainly amorphous iron oxide, of which size ranged from 2 to 10 nm and mainly consisting of Fe, O, and Si (step 2). At pH=9.5, nesquehonite [$Mg(HCO_3)(OH){\cdot}2(H_2O)$] and lasfordite [$MgCO_3{\cdot}H_2O$] were formed after reaction with $CO_2$ (step 3). The size of carbonated minerals was ranged from 1 to $6{\mu}m$. These results indicated that the acid treatment of serpentine and pH swing processes for the serpentine can be used for synthesis of other materials such as silica, iron oxides and magnesium carbonate. Also, This process may be useful for the precursor synthesis and $CO_2$ sequestration via mineral carbonation.

• Microbiology and Biotechnology Letters
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• v.3 no.3
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• pp.123-134
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• 1975

Out of 96 yeast strains isolated from various natural habitats, five strains were screened based on their ability to ferment agricultural biproducts such as rice-, barley-and wheat-bran, and sawdust. These were identified as Hansenula anomala var anomala, Candide utilis, C. pelliculosa, Debaryomyces hansenii, and Irpex lacteus. Using these yeasts the above mentioned agricultural biproducts were fermented in various combinations. The fermented product was fed to 180 male Starcroses for eight weeks and obtained a body weight increase of 15.1g a day, while the unfermented control feed increased 10.5g a day.

• Korean Journal of Microbiology
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• v.53 no.2
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• pp.83-96
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• 2017

A constructed sea stream in Yeongdo, Busan, Republic of Korea is mostly static due to the lifted stream bed and tidal characters, and receives domestic wastewater nearby, causing a consistent odor production and water quality degradation. Bioaugmentation of a microbial consortium was proposed as an effective and economical restoration technology to restore the polluted stream. The microbial consortium activated on site was augmented on a periodic basis (7~10 days) into the most polluted site (Site 2) which was chosen considering the pollution level and tidal movement. Physicochemical parameters of water qualities were monitored including pH, temperature, DO, ORP, SS, COD, T-N, and T-P. COD and microbial community analyses of the sediments were also performed. A significant reduction in SS, COD, T-N, and COD (sediment) at Site 2 occurred showing their removal rates 51%, 58% and 27% and 35%, respectively, in 13 months while T-P increased by 47%. In most of the test sites, population densities of sulfate reducing bacterial (SRB) groups (Desulfobacteraceae_uc_s, Desulfobacterales_uc_s, Desulfuromonadaceae_uc_s, Desulfuromonas_g1_uc, and Desulfobacter postgatei) and Anaerolinaeles was observed to generally decrease after the bioaugmentation while those of Gamma-proteobacteria (NOR5-6B_s and NOR5-6A_s), Bacteroidales_uc_s, and Flavobacteriales_uc_s appeared to generally increase. Aerobic microbial communities (Flavobacteriaceae_uc_s) were dominant in St. 4 that showed the highest level of DO and least level of COD. These microbial communities could be used as an indicator organism to monitor the restoration process. The alpha diversity indices (OTUs, Chao1, and Shannon) of microbial communities generally decreased after the augmentation. Fast uniFrac analysis of all the samples of different sites and dates showed that there was a similarity in the microbial community structures regardless of samples as the augmentation advanced in comparison with before- and early bioaugmentation event, indicating occurrence of changing of the indigenous microbial community structures. It was concluded that the bioaugmentation could improve the polluted water quality and simultaneously change the microbial community structures via their niche changes. This in situ remediation technology will contribute to an eco-friendly and economically cleaning up of polluted streams of brine water and freshwater.