• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.129-135
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• 2006

This study was performed to characterize the seasonal variation of water quality and sediment environment from May, 2004 to February, 2006 in 21 stations of Gwangyang bay. Gawngyang bay is located in the middle of south coast of Korea and semi-dosed with Yeosu peninsula, Gwangyang-city and Namhea-do. Water quality at the west coast of Myo-do were highly deteriorated than other stations. At summer season(July 2005), the concentration of the most analytical items were highly detected than other seasons and the lowest concentration was at the winter season(January 2005, February 2006). Especially, DIP and TP were highly detected around the coast of Yeosu industrial complex. N/P ratio were higher than 16 of Redfield ratio in the spring(May 2005) and winter(February 2006) at the surface layer. While at other seasons and most stations were lower than 16 of Redfield ratio. In the survey of sediment environment, ignition loss(IL), chemical oxygen demand(COD) and acid volatile sulfide(AVS) were in the range of $2.51\sim22.10%,\;2.65\sim48.41mg/g-dry\;and\;0.01\sim8.95mg/g-dry$, respectively. COD in surface sediment was highest at summer season AVS was highest at autumn. In sediment, the corelationship coefficients between COD and IL, COD and AVS were 0.65 and 0.44, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.9
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• pp.526-532
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• 2015

A bioreactor filling with pellets and stones was equipped to the swine manure treatment system, which is expected to emit high concentration of odor in the process of the organic wastewater treatment system, and in comparison with the activated sludge process as the control process, the reactor operation state, treatment water quality and odor emission concentration were measured. The reactor using the bioreactor proved to be much more stable in the bubble condition, treatment water transparency, etc, and BOD removal efficiency was also much better. The removal efficiency of T-N and T-P, however, showed little difference in the two reactors. Odor, as a result of examining $NH_3-N$, $NH_3$ concentratio, and complex odor, was 4 times to 24 times less emitted in the system using bioreactor than in the activated sludge system. $H_2S$, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide were not found or were found in only 5 ppbs in each reactor and showed little difference between the two reactors. In the bioreactor process, Bacillus sp./ Pseudomonas sp. species were mainly found and in the activated sludge process, acterium sp. Chryseobacterium sp. species were mainly found.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.291-297
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• 2011

In an attempt to improve the substrate condition for Manila clam (Ruditapes philippinarum) culture, crushed oyster (Crassostrea gigas) shells were spread on the muddy tidal flat of Namseong-ri, Podu-myeon, Goheung-gun, Jeollannam-do in April 2008. To test the suitability of the crushed oyster shell added substrate, seed clams were transplanted from Taehwa river estuary in Ulsan city in June 2008. Over 23 months of sampling, the mean grain size and the sorting in the experimental site containing the crushed oyster shell were significantly higher than the control site. The ignition loss, water content, chemical oxygen demand (COD) and acid-volatile sulfide (AVS) level were also significantly higher in the crushed oyste shell added substratum. Survival of the clams transplanted to the crushed oyster shell added substratum was significantly higher and all the clams transplanted to the normal muddy substratum died in August 2009, 13 months after the transplantation. At the end of the experiment in April 2010, the transplanted clams reached 36.10 mm in shell length and 8.92 g in total weight with survival of 43.5%. Our study suggested than crushed oyster shell added in the mud dominant substratum greatly improved living condition and survivability of clams.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1202-1208
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• 2009

Synbiotics is the term used for a mixture of probiotics (live microbial feed additives that beneficially affects the host animal) and prebiotics (non-digestible food ingredients that beneficially affect the organism). This study investigated the effect of probiotics from anaerobic microflora with prebiotics on growth performance, nutrient digestibility, noxious gas emission and fecal microbial population in weaning pigs. 150 pigs with an initial BW of 6.80${\pm}$0.32 kg (20 d of age) were randomly assigned to 5 dietary treatments as follows: i) US, basal diet+0.15% antibiotics (0.05% oxytetracycline 200 and 0.10% tiamulin 38 g), ii) BS, basal diet+0.2% synbiotics (probiotics from bacteria), iii) YS, basal diet+0.2% synbiotics (probiotics from yeast), iv) MS, basal diet+0.2% synbiotics (probiotics from mold), v) CS, basal diet+0.2% synbiotics (from compounds of bacteria, yeast and mold). The probiotics were contained in $10^{9}$ cfu/ml, $10^{5}$ cfu/ml and $10^{3}$ tfu/ml of bacteria, yeast and molds, respectively. The same prebiotics (mannan oligosaccharide, lactose, sodium acetate and ammonium citrate) was used for all the synbiotics. Pigs were housed individually for a 16-day experimental period. Growth performance showed no significant difference between antibiotic treatments and synbiotics-added treatments. The BS treatment showed higher (p<0.05) dry matter (DM) and nitrogen digestibility while ether extract and crude fiber digestibility were not affected by the dietary treatment. Also, the BS treatment decreased (p<0.05) fecal ammonia and amine gas emissions. Hydrogen sulfide concentration was also decreased (p<0.05) in BS, YS and MS treatments compared to other treatments. Moreover, all the synbioticsadded treatments increased fecal acetic acid concentration while the CS treatment had lower propionic acid concentration than the US treatment (p<0.05) gas emissions but decreased in fecal propionate gas emissions. Total fecal bacteria and Escherichia coli populations did not differ significantly among the treatments, while the Shigella counts were decreased (p<0.05) in synbiotics-included treatment. Fecal bacteria population was higher in the YS treatment than other treatments (p<0.05). The BS treatment had higher yeast concentration than YS, MS and CS treatments, while US treatment had higher mold concentrations than MS treatment (p<0.05). Therefore, the results of the present study suggest that synbiotics are as effective as antibiotics on growth performance, nutrient digestibility and fecal microflora composition in weaning pigs. Additionally, synbiotics from anaerobic microflora can decrease fecal noxious gas emission and synbiotics can substitute for antibiotics in weaning pigs.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.965-974
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• 2009

This study evaluated the degradation efficiency of malodorous sulfurized-organic compounds by utilizing N- and Sdoped titanium dioxide under visible-light irradiation, and examined the catalyst deactivation and regeneration. Catalyst surface was characterized by employing Fourier-Transform-Infrared-Red (FTIR) spectra. The visible-light-driven photocatalysis techniques were able to efficiently degrade low-level dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) with degradation efficiencies exceeding 97%, whereas they were not effective regarding the removal of high-level DMS and DMDS, with degradation efficiencies of 84 and 23% within 5 hrs of photocatalytic processes. As compared with DMS, DMDS which containes one more sulfur element revealed quick catalyst deactivation. Catalyst deactivation was confirmed by the equality between input and output concentrations of DMD or DMDS, the obsevation of no $CO_2$ generation during a photocatalytic process, and the FTIR spectrum peaks related with sulfur ion compounds, which are major byproducts formed on catalyst surfaces. The mineralization efficiency of DMS at 8 ppm, which was a peak value during a photocatalytic process, was calculated as 144%, exceeding 100%. The catalyst regenerated by high-temperature calcination exhibited higher catalyst recovery efficiency (53 and 58% for DMDS and DMS, respectively) as compared with dry-air and humid-air regeneration processes. However, even the calcined method was unable to totally regenerate deactivated catalysts.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.4
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• pp.164-173
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• 2004

Field survey on the marine environmental characteristics by the distribution of dinoflagellate cysts and organic matter was carried out bimonthly at 6 stations in Gamak Bay, the southern part of Korean Peninsula from June 2000 to April 2001. The range of environmental factors on vertical sediments such as ignition loss (IL), chemical oxygen demand (CODs), total sulfide (H₂S), particulate organic carbon (POC), particulate organic nitrogen (PON) and phaeopigment were 3.21∼11.18％. 12.25∼99.26 mgO₂/g dry, 2.49∼116.18 ㎍/g dry, 2.91∼116.18 mgC/g dry, 0.53∼2.82 mgN/g dry and 2.49∼116.18 ㎍/g dry, respectively. A total of 38 species dinoflageuate cysts belonged to 21 genera, 36 species, and 2 unidentified species. A cysts density were 18∼3,836 cysts/g dry. Vertical distribution of organic matter and dinoflagellate cysts was rapidly decreased from surface to deeper sediment. The eutrophication in the northwestern parts of Gamak Bay might originated since 1980s.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1319-1330
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• 2000

Activated carbons prepared by chemical activation of organic waste sludges with $ZnCl_2$ and $K_2S$ have been studied in terms of their pore development and adsorptivity. Pore development of the carbons prepared from organic waste sludges was characterized by the nitrogen adsorption at 77K. The $ZnCl_2$-activated carbon produced by chemical activation with zinc chloride exhibited type I isotherm characteristics according to the BDDT classification, suggesting the presence of micropores formed by activation process. The isotherms of the commercial powdered activated carbon and $K_2S$-activated carbon reveal a hysteresis similar to that of type IV in BDDT classification, indicating the formation of mesopores. This result implies that the major pores of $K_2S$-activated carbon are composed of meso and micropores, and a macropores are minor. The adsorptive capacities of metal on the $K_2S$-activated carbon prepared from organic waste sludges were found to be superior to those on a commercial granular activated carbon. The Langmuir and Freundlich isotherms yield a fairly good fit to the adsorption data, indicating a monolayer adsorption of metals onto $K_2S$-activated carbon. The adsorptive capacity of the $K_2S$-activated carbon was superior to $ZnCl_2$-activated carbon for $PO_4$-P, and vice versa for $NO_3$-N. From the results of the studies reported here, it can be concluded that activated carbons with adsorptivity superior to commercial granular activated carbons can be produced from organic waste sludge using a two-step carbonization/activation procedure with zinc chloride or potassium sulfide as the activating agents.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.577-588
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• 1995

The chemical constituents for the seawater and sediment were measured to evaluate pollution in the sea around Pusan Harbor in winter, n992. The average value of trophic state index (TSI) was 19.4 at the outside of Buk Harbor, 50,4 at the inside of Buk Harbor, 56,3 at the Nam Harbor and 5,0 at the Kamchun Harbor. The high correlation found in salinity-nutrients diagram with AOU suggested that the enrichment of nutrients in Pusan Harbor during winter was mainly due to the influx of terrestrial effluents and partially by regenerated nutrients from suspended organic matters in the water column. The mean values of total ignition loss (TIL), COD and total sulfide in the surface sediments were$12.1\%$, 17.5 mg/g.dry wt. and 1.18 mg/g.dry wt. respectively. The highest level of those parameters was shown mostly at the inside of Buk Harbor. The mean concentration of total organic carbon (TOC), total organic nitrogen (TON), and total phosphorus were 24.9 mg/g.dry wt., 1.3mg/g.dry wt. and 0.69 mg/g. dry wt., respectively, Both of the highest level for TOC and total phosphorus have found at the Nam Harbor. On the other hand, the Highest level for TON was found at the inside of Buk Harbor. The TOC/TON atomic ratio with a range of 10.2-60.2 (mean value of 22.5) strongly indicated the active role of the input from the terrestrial organic pollutants.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.392-402
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• 2020

We investigated the concentrations of acid volatile sulfide (AVS), ignition loss (IL), total organic carbon (TOC), total nitrogen (TN), and metallic elements (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn), in August 2015, to determine the spatial distribution and pollution status of organic matter and metals in the surface sediment of Jinju Bay, a spraying shellfish farming area, Korea. The concentrations of organic matter and metallic elements were significantly higher in the southern part of the bay than in the mouth and center of the bay. The C/N ratio (5.7~8.0) in the sediment represents the dominance of organic matter of oceanic origin in the surface sediment of the study area. The concentrations of AVS, TOC, and metals (As, Cd, Cr, Cu, Hg, Pb, and Zn) were much lower than the values of the sediment quality guidelines applied in Korea. Based on the results of the pollution load index (PLI) and ecological risk index (ERI), the metal concentrations in the surface sediment of Jinju Bay have a weakly negative ecological effect on benthic organisms although the sediments with high metal pollution status are distributed in the southern parts of the bay, with high dense shellfish farming areas. Thus, the surface sediments in Jinju Bay are not polluted with organic matter and are slightly polluted with metallic elements.

• Journal of the Mineralogical Society of Korea
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• v.30 no.3
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• pp.103-112
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• 2017

In order to transform arsenopyrite into pyrrhotite and to decrease As content by less than 2,000 mg/kg, pulp sample and non-magnetic pulp sample were heated in a microwave oven at different heating times and were separated through wet-magnetic separation. As the microwave heating time increased, the phase of pyrrhotite was extended to become arsenopyrite entirely. The melting pores and micro-cracks occurred on the pyrrhotite due to hot spot phenomenon with microwave heating. The heated raw pulp sample (As content : 19,970.13 mg/kg) and non-magnetic pulp sample (As content : 19,970.13 mg/kg) which were heated in a microwave oven for 10 minutes were separated through wet-magnetic separation and magnetic fraction containing less than 2,000 mg/kg of As content was recovered only from the heated sample of magnetic separation. It was discovered that for the sulfide complex ore with As penalty imposed on, if microwave heating and wet-magnetic separation are effectively utilized, magnetic fraction. We expect to be able to obtain ore minerals with an arsenic content below the penalty charge.