• Environmental Analysis Health and Toxicology
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• v.13 no.3_4
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• pp.77-85
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• 1998

It is very frequent that LAS meets the chlorine bleaches not only in the processes but also in the path from the sewages to the rivers. Therefore, it is not difficult to imagine that the harmful substances like DBPs are produced when LAs reacts with free chlorine. THMs are the major components of DBPs which are formed by reactions of organic substances with the chlorine oxidants. Among them, chloroform is the most noteworthy material. Since the major behavior observed was the formation of chloroform during reaction of LAS with free chlorine, the models were developed to grasp the tendency of chloroform formation depending on condition. According to these models, the effect of pH in the formation of chloroform is most grave.

• Korean Journal of Microbiology
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• v.18 no.4
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• pp.155-160
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• 1980

Microorgansims utilizing anionic detergent as their carbon and sulfur sources were isolated from soils and sewages. Alkyl benzene sulfonate (Hiti) and sodium dodecyl sulfonate (SDS) were the detergent compound tested. Three of these isolated microorganisms were identified as Pseudomonas spp. and the others asKlbsiella, Enterobacter and Acinetobacter. Biodegradation rate of the detergents and growth rate of Acinetobacter Strain II-8, Pseudomonas strain H-3-1 and 554 among six isolated microorganisms were investigated with colorimetric, warburg manometric, and ultraviolet absorption analyses. By performance of 4 serial successive tranfer to new culture broth for the purpose of adaptation method, ABS and SDS could be degraded to far more than 40%-60% and 70%-75%, respectively. However the employment of nonadaptation method, ABS and SDS were degraded to 30%-45% and 45%-65%, respectively. In another words, detergents degradation ability was increased to a certain extent by successive transfer to the new minimal media. We would conclude that the development of adaptation was effective in the removal of recalcitrant compounds.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.167-176
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• 2015

The water quality of the Gulpo Stream flowing through Incheon, Bucheon, Seoul, and Kimpo is getting worse due to a slow flow rate and bank constructions by stream channelization as well as an inflow of pollutants from living-sewages and factory-sewages. Besides, a dry stream phenomenon caused by a lack of maintenance water upstream makes a self-purification system worse, and the water quality of the Gulpo Stream is currently at its lowest level. The accumulated sludge of the streambed is mostly formed by the deposition of particle pollutants due to the slow flow rate and an artificially straightened stream channel. This accumulated sludge adsorbs a great quantity of organic materials and heavy metals. Because of the internal contamination possibility by a re-gushing, even after the pollution source is removed, it can cause future water pollution. Without a total examination as previously recommended, it is considered difficult to accomplish practical efficiency. In conclusion, the management of periodic sediment management such as dredging would be necessary in the Gulpo Stream because sediment could be an internal pollution source of stream water under anaerobic conditions.

• 한국해양학회지
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• v.7 no.1
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• pp.24-45
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• 1972

The Han River is an important water source in Seoul and neighbouring districts, for public and industrial supply, and for agriculture and fishery. Nowadays, more than six million inhabitants are supplied withe water from this river. The total length of the river is 470km, and has 17 10$\^$9/㎥ an average annual flow. The hydrographic characteristics at Seoul are 653㎥/sec in an average flow, 4,608㎥/sec in the maximum average flow, and 201㎥/sec in the minimum average flow. These are influenced in some degree by snowmelt in early spring, and greatly by the flood during summer. For the pollution problems, the periods of low flow are critical ones. As a rule they occur around the months November through June. Nowadays, most of the sewage from towns and industries is discharged untreated. Apart from domestic and industrial sewages, there are some discharges of mineral matter by mines in the upriver region. In general, water quality of the Han River is kept very clean and healthy until Kwangnaru of the upper region of Seoul. A large pollution, however, is received in the downstream by the domestic and industrial sewages of Seoul. It can be seen that dissolved oxygen, COD and BOD$\sub$5/ diminish markedly, and the intensity of almost every water parameter of the river continues to increase. Comparison of the figures for 1971 derived from a sampling point 40km downstream of Kwangnaru leads to the conclusion that hardness, Ca and Mg were no changed; alkalinity, Si and soluble- Fe were slightly increased; CO$\sub$2/, acidity, Cl, NO$\sub$2/-N, Cu, Zn and Al were increased in 2 and 3 times; total residue, total ignitious residue, COD, BOD$\sub$5/, NH$\sub$4/-N, PO$\sub$4/-P, Mn, Pb and total-Fe were increased in 4 to 7 times; and SO$\sub$4/, particulate-Fe and Cd were increased in 10 to 11 times. On the other hand, coliforms were increased in 650 times; fecal coliforms in 365 times; enterococci and total plate counts in 30 times, respectively. In view points of water quality standards, the down Han River water is now leveling out in Cd, coliforms and fecal coliforms for the agricultural use; in dissolved oxygen and some trace elements (Cu, Zn, Pb and Cd) for the fishery use; in ammonia, COD, BOD$\sub$5/, and Cd for the drinking use.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.51-57
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• 2005

In order to prevent the environmental pollution, the dryers are commonly used to treat sludge that one of sewages is polluting the quality of water. Generally, the drying method is various as to the property of material and use. Rotary dryer is a good apparatus to treat them. The rotary dryer is the way that is to make substance transmission and heating using hot air between sludge particles and heated gas. In this paper, we performed a numerical analysis of the inner air flow of the 3-pass rotary dryer through the changing rotational speed from 3rpm to 10rpm. In this result, we found that 3rpm is effective to dry material in terms of heat transfer because large scale velocity fluctuation is occurred inside the first and second drum. Also we confirmed that 5rpm and 8rpm showed up uniform flow at the center area of the first drum.

• Journal of Korean Society on Water Environment
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• v.28 no.3
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• pp.409-417
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• 2012

SWAT model was applied for the Nakdong River Basin to characterize water quality variability and assess the feasibility of using the load duration curve to water quality management. The basin was divided into 67 sub-basins considering various watershed environment, and rainfall runoff and pollutant loading were simulated based on 6 year measurements of meteo-hydrological data, discharge data of treatment plants, and water quality data (SS, T-N and T-P). The results demonstrate that non-point source loads during wet season increase by 80 ~ 95% of total loads. Although the rate of water flow governs the amount of SS that is transported to the main streams, nutrient concentrations are highly elevated during dry season by being concentrated. This phenomenon is more pronounced in the lower basin, receiving large amounts of urban point source discharges such as treated sewages. Also, the load duration curves (LDC) demonstrate dominant source problems based on the load exceedances, showing that SS concentrations are associated with the rainy season and nutrients, such as T-P, may be more concentrated at low flow and more diluted at higher flow. Overall, the LDC method could be used conveniently to assess watershed characteristics and pollutant loads in watershed scale.

• Hwankyungkyoyuk
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• v.5 no.1
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• pp.19-33
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• 1993

This result showed that the middle school students' response for the environment condition was highly negative. The major findings of this study are as follows. 1. Students would become to know the environmental pollution through reading of newspapers and TV rather than school education. 2. Students' response for air and water pollution was seriously accepted in city areas than in country areas, and in large cities than in small cities. 3. Students' response for air pollution showed that the quality of air was getting worse and major factor of air pollution was the exhausts of automobiles. 4. It showed that students' concern for water pollution was increased and water pollution was being accelerated by the increase of domestic and industrial sewages, the overuse of the agricultural chemicals, the entrophication and acid rain. 5. Students thought that soil pollution was mainly due to factory sewage, life sewage, heavy metal and agricultural medicines and so on. But now they think it is due to the degenerated and inseparable things such as used vinyle for farm and plastics. 6. Most students thought of the pollution of our country as serious. But they thought it could be removed if we tried to get rid of pollution. 7. Now students' consciousness to protect the nature took an active interest turn and was strong. Putting these various findings together, I suggested that, the efforts to turn students affirmative consciousness for the environment and a powerful plan by the nation to take off pollution should be needed. Also the education to enforce the environment preservation had to be needed.

• Microbiology and Biotechnology Letters
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• v.3 no.3
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• pp.117-122
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• 1975

In order to develop an activated sludge which can be used for both waste treatment and protein source of animal feed, microorganisms were isolated from sewages of various wheat or sweet potato starch processing plants and their activities were tested. Out of 32 isolates which composed of two protozoan genera and 13 bacterial strains, were screened and three bacterial stranis were found to be most effective in both floe-formation and wheat starch waste liquid stabilization.

• Clean Technology
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• v.21 no.2
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• pp.108-116
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• 2015

Hydrogen sulfide and ammonia are one of the common malodorous compounds that can be found in emissions from many sewages treatment plants and industrial plants. Therefore, removing these harmful gases from emissions is of significance in both life and industry because they can cause health problems to human and detrimental effects on the catalysts. In this work, pyrolytic carbon blacks from waste tires were used to develop adsorbent with good adsorption capacity for removal of hydrogen and ammonia. Pellet-type adsorbents were prepared by a mixture of carbon black, metal oxide and sodium hydroxide or hydrochloric acid, and their adsorption capacities were estimated by using breakthrough curve of a continuous fixed bed adsorption column at ambient condition. The adsorbent manufactured with a mixture of carbon black, iron oxide(III) and sodium hydroxide showed the maximum working capacity of hydrogen sulfide. For ammonia, maximum working capacity was obtained by the adsorbent manufactured with a mixture of carbon black, copper oxide(II) and hydrochloric acid.

• Journal of Environmental Science International
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• v.13 no.9
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• pp.789-798
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• 2004

Physicochemical characteristics of Kwangyang Bay, have been investigated on the effects of inputting rivers just after rainy season in summer 2003. The results ranged from 4.96～8.01 mg/L for DO, 1.16～3.09 mg/L for COD, 7.21～67.71 uM for DIN and 0.12～121.84 uM for phosphate. The COD of Yeosu Area was 1.19～3.09 mg/L, Kwangyang Area was 1.23～2.76 mg/L. The COD of Wallae cheon in Yeosu Area was 3.09 mg/L and Donghoan in Kwangyang Area was 2.76 mg/L. The reason of high COD might be industrial sewage of organic chemical plants and iron foundry. DIN of Yeosu Area and Kwangyang Area were 7.21～63.43 ${\mu}M$ and 8.43～67.71 ${\mu}M$ respectively. The average phosphate of Yeosu Area was 23.65 u. The source of phosphate might be industrial sewages of fertilizer plant and phosphate gypsum stocked with high amounts. The metal concentrations were measured in the range of 1.01～175.10 ${\mu}g/L$ for Cu, 0.13～1.78 ${\mu}g/L$ for Cd, 1.13～5.21 ${\mu}g/L$ for Pb, 1.58～13.57 ${\mu}g/L$ for Cr and 1.07～20.68 ${\mu}g/L$ for As. The average Cu concentration was 78.99 ${\mu}g/L$ in Kwangyang Area. The source of Cu might be industrial sewage of iron foundry. The average Cr concentration of Yeosu Area was 9.07 ${\mu}g/L$. That is 2 times higher than Kwangyang Bay 5.74 ${\mu}g/L$, because of sewage of chemical plants.