• 상하수도학회지
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• 제24권4호
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• pp.395-406
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• 2010

In this study, anaerobic digestion, electro-oxidation and electro-fenton oxidation processes were investigated to reduce oily refinery sludge. Anaerobic digestion process was not suitable for oily activated sludge reduction because of characteristics itself and, as experimental results revealed, reduction efficiency was low for electro-oxidation process. However, 40% total suspended solid reduction of oily activated sludge was obtained by electro-fenton oxidation process, operating at pH=1, 0.5 A and $Fe^{2+}$:$H_2O_2$ ratio = 1:30. In addition, higher reduction efficiency was obtained as reaction time was increased (30, 60, 90, 120 min) despite of low $H_2O_2$ concentration. From the results, it has been investigated that electro-fenton oxidation is efficient process for oily activated sludge reduction.

• 한국환경과학회지
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• 제10권6호
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• pp.431-436
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• 2001

Variations in phytoplankton concentrations result from changes of the ocean color caused by phytoplankton pigments. Thus, ocean spectral reflectance for low chlorophyll waters are blue and high chlorophyll waters tend to have green reflectance. In the Korea region, clear waters and the open sea in the Kuroshio regions of the East China Sea have low chlorophyll. As one moves even closer In the northwestern part of the East China Sea, the situation becomes much more optically complicated, with contributions not only from higher concentration of phytoplankton, but also from sediments and dissolved materials from terrestrial and sea bottom sources. The color often approaches yellow-brown in the turbidity waters (Case Ⅱ waters). To verify satellite ocean color retrievals, or to develop new algorithms for complex case Ⅱ regions requires ship-based studies. In this study, we compared the chlorophyll retrievals from NASA's SeaWiFS sensor with chlorophyll values determined with standard fluorometric methods during two cruises on Korean NFRDI ships. For the SeaWiFS data, we used the standard NASA SeaWiFS algorithm to estimate the chlorophyll_a distribution around the Korean waters using Orbview/ SeaWiFS satellite data acquired by our HPRT station at NFRDl. We studied In find out the relationship between the measured chlorophyll_a from the ship and the estimated chlorophyll_a from the SeaWiFs satellite data around the northern part of the East China Sea, in February, and May, 2000. The relationship between the measured chlorophyll_a and the SeaWiFS chlorophyll_a shows following the equations (1) In the northern part of the East China Sea. Chlorophyll_a =0.121Ln(X) + 0.504, R²= 0.73 (1) We also determined total suspended sediment mass (55) and compared it with SeaWiFS spectral band ratio. A suspended solid algorithm was composed of in-.situ data and the ratio (L/sub WN/(490 ㎚)L/sub WN/(555 ㎚) of the SeaWiFS wavelength bands. The relationship between the measured suspended solid and the SeaWiFS band ratio shows following the equation (2) in the northern part of the East China Sea. SS = -0.703 Ln(X) + 2.237, R²= 0.62 (2) In the near future, NFRDI will develop algorithms for quantifying the ocean color properties around the Korean waters, with the data from regular ocean observations using its own research vessels and from three satellites, KOMPSAT/OSMl, Terra/MODIS and Orbview/SeaWiFS.

• 한국수산과학회지
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• 제19권4호
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• pp.339-346
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• 1986

낙동강 하류역의 부영양화에 관한 연구로서 1983년 10월부터 1984년 9월까지 1년간 조사된 결과를 요약해 보면 다음과 같다. 1. 낙동강 하류역의 영양염류의 분포를 보면 암모니아 질소 농도범위 및 평균농도는 $0.22{\sim}173.37{\mu}g-at/l,\;43.38{\mu}g-at/l$이며 질산 질소 농도는 $26.68{\sim}186.85{\mu}g-at/l,\;68.89{\mu}g-at/l$, 아질산 질소 농도는 $1.07{\sim}8.22{\mu}g-at/l,\;3.08{\mu}g-at/l$, 총무기 질소 농도는 $58.65{\sim}231.68{\mu}g-at/l,\;115.35{\mu}g-at/l$, 인산염인 농도는 $0.44{\sim}4.43{\mu}g-at/l,\;1.56{\mu}g-at/l$로 나타나고있어 영양염류의 함양이 다른 하천에 비하여 매우 높았다. 2. N/P비율은 물금이 119.6으로 가장 높고 구포가 80.7, 하단이 63.5로 영양염류중 인에 비하여 질소의 함유비율이 매우 높은 특징을 가지고 있었다. 3. 클로로필 a양의 농도범위는 $1.8{\sim}75.16\;mg/m^3$였으며 물금지점이 평균 $33.98mg/m^3$로 전조사기간을 통해 구포나 하단지점보다 월등히 높은 농도분포를 보이고 있으며 여름에 평균농도가 물금이 $56.38mg/m^3$, 구포가 $31.34mg/m^3$ 하단이 $16.85mg/m^3$로 대단히 높은 농도이다. 4. 총부유물질은 물금이 평균 10.65ppm, 구포가 15.80ppm, 하단이 45.90ppm로 하단이 가장 높고 휘발성 부유물질은 물금이 평균 3.63ppm, 구포가 3.40ppm, 하단이 8.20ppm이며 총부유물질중의 휘발성부유물질량의 비로 본다면 물금이 $35.2\%$, 구포가 $22.9\%$, 하단이 $16.2\%$로 물금지점이 휘발성 부유물질 함유비율이 가장 높다. 5. 호소의 영양도에 적용해 보면 클로로필 a양으로서는 물금과 구포지점에서는 겨울을 제외한 전계절에서 부영양화상태이고 무기태 질소량으로서는 전지점이 부영양화 상태이며 인산염양으로서는 전지점이 중부영양 상태이다. 이상의 결과에서 고찰해 보면 현재 강들이 흐르는 상태에서 영양염류의 함량이 매우 많은 부영양화 상태에 있으므로 이러한 강물이 하구언이 설정되어 저류하게 된다면 부영양화의 진행에 의해 수질 악화가 예상된다.

• 한국농공학회논문집
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• 제48권3호
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• pp.23-34
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• 2006

This study reviews the applicability of the GWLF (Generalized Watershed Loading Function) model, which is based on a loading function that requires only a relatively small amount of data, in a small agricultural watershed. The hydrological data was collected from 1996 to 2004 for a study area based on the HP#6 upper stream reservoir small watershed area. This data was then used to calibrate and verify the model. A simulation based on the model yielded $R^2$ values of $0.47\sim0.89$. This is considered to have high applicability when compared to the simulation and the observed results, which yielded relatively high values of $R^2$ for SS (Suspended Solid), TN (Total Nitrogen), and TP (Total Phosphorus) of 0.58, 0.47 and 0.62, respectively. This study provides a useful approach fur researchers selecting appropriate models to use the insufficient measuring data for rural watersheds.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 Proceedings of the 4th Korea-China Joint Workshop on Nuclear Waste Management
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• pp.12-27
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• 2004

Pretreatment process consisted of submerged hollow-fiber microfiltration(HMF) membrane and spiral-wound nanofiltration(SNF) membrane has been developed by NETEC, KHNP for the purpose of improving the impurities of liquid radioactive waste before entering Selective Ion Exchange System(SIES). The lab-scale combined system was installed at Kori NPP #2 nuclear power plant and demonstration tests using actual liquid radioactive waste were carried out to verify the performance of the combined system. The submerged HMF membrane was adopted for removal of suspended solid in liquid radioactive waste and the SNF membrane was used for removal of particulate radioisotope such as, Ag-l10m and oily waste because ion exchange resin can not remove particulate radioisotopes. The liquid waste in Waste Holdup Tank (WHT) was processed with HMF and SNF membrane, and SIES. The initial SS concentration and total activity of actual waste were 38,000ppb and $1.534{\times}10_{-3}{\mu}Ci/cc$, respectively. The SS concentration and total activity of permeate were 30ppb and lower than LLD(Lower Limit of Detection), respectively.

• 한국수산과학회지
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• 제37권6호
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• pp.492-497
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• 2004

Waste concentration and waste generation rate in seawater aquaria by common conger (Astrocongey myriaster) and olive flounder (Paralichyhus olivaceus) were investigated. The initial fish density of common conger and olive flounder were $3{\%}\;and \;2.8{\%}$ of total weight of aquarium water, respectively Wastes in the seawater aquaria, such as protein, total suspended solid (TSS), ammonia, turbidity and chemical oxygen demand (COD) increased with days after stocking. Protein generation rate of common conger increased until 1 day after stocking while that of olive flounder increased until 3 days. The average protein generation rates of common conger and olive flounder were $0.28g/kg{\cdot}day\;and\;0.21g/kg{\cdot}day$, respectively. The trends of other waste generation rate were similar to protein generation rate.

• 대한환경공학회지
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• 제36권2호
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• pp.84-95
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• 2014

최근 미국과 일본을 중심으로 높은 공극과 압축성이라는 장점을 지닌 압축성 섬유여재 여과에 대한 다양한 기술이 개발되면서 이를 이용한 집약적 하 폐수 처리에 대한 관심이 높아지고 있다. 이에 따라 본 연구에서는 다양한 유입수질의 하수에 대하여 압축성 섬유여재 여과의 적용성을 검토하고자 하며, 해당 유입수에 대한 최적의 운전조건을 도출하고자 한다. 이를 위하여 예비 실험으로서 추적자 시험을 진행하였으며, 이를 통하여 다양한 압축률 및 여과율에서의 여과 양상을 검토하였다. 그 결과 높은 압축률에서 높이에 따라 다른 공극률이 적용되어 이론적인 결과값과의 뚜렷한 차이를 관찰할 수 있었다. 하수처리장의 침사지 유출수를 대상으로 다양한 압축률 조건에서 압축성 섬유여재 여과의 TSS 제거 및 제거 입자크기분포를 살펴본 결과, 압축률 30%가 최적의 운전조건으로서 제거효율 70% 이상을 나타냈으며, 작은 크기의 입자 제거율 증대를 위해 최소 15% 이상의 압축률이 요구되었다. 또한 여과 유출수 농도의 주요 영향인자인 $10{\mu}m$ 이하 입자의 제거 효율을 증대시키기 위해서는 응집과 같은 추가 공정이 필요하다고 판단되었다. 모델링 결과를 통하여 압축률이 증가할수록 여과 초기에 입자 크기에 따른 TSS 제거효율이 두드러지게 나타남을 관찰하였고, 유입수의 입자크기분포에서 가장 큰 비율을 차지하는 $10{\mu}m$ 크기 입자를 대상으로 높이에 따른 모델링 결과 높이 150-300 mm 여재층이 해당 입자 크기에 대하여 가장 활발한 여과 작용을 나타내었다.

• Korean Chemical Engineering Research
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• 제55권6호
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• pp.816-821
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• 2017

하수 및 폐수 내 고농도의 인 및 부유물질 제어를 위해 개발한 일체형 완속교반/침전 그물망 압착식 섬유여과시스템을 이용하여 하수처리장의 반류수 내 부유성 고형물 및 인 처리에 적용했을 경우에 따른 성능을 검토하고자 하였다. 6가지 Mode로 실험을 하였으며, 16.7, 33.3, 41.7 및 50.0 ton/day 유량과 Al/P 몰비 2~4의 조건에서 실험을 행하였다. 응집제를 주입하였을 경우에 모두 높은 총인(T-P) 제거 효율을 보였지만 연속운전시간이 7.8 min~11.4 min으로 짧아지는 단점이 생겼다. 이를 극복하기 위해 일체형 완속교반/침전 그물망 압착식 섬유여과시스템을 응집/급속교반/공기주입/완속교반/침전공정 및 여과공정으로 진행 시 연속운전시간이 88.2 min으로 다른 모드로 운전한 결과에 비해 8~11.3배 정도 증가하였다. 역세수량율도 5.4%로 매우 낮게 나타남에 따라 이 공정이 가장 효율적인 처리방안으로 평가되었다.

• 생태와환경
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• 제41권4호
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• pp.472-484
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• 2008

The calibrated Andong Reservoir hydro-dynamic module (PART I) of the 2-dimensional hydrodynamic and water quality model, CE-QUAL-W2 [v3.2], was applied to examine the dynamics of total phosphorus, and chlorophyll $\alpha$ concentration within Andong Reservoir. The modeling effort was supported with the data collected in the field for a five year period. In general, the model achieved a good accuracy throughout the calibration period for both chlorophyll ${\alpha}$ and total phosphorus concentration. The greatest deviation in algal concentration occurred on $10^{th}$ October, starting at the layer just beneath the surface layer and extending up to the depth of 35 m. This deviation is principally attributed to the effect of temperature on the algal growth rate. Also, on the same date, the model over-predicts hypolimnion and epilimnion total phosphorus concentration but under-predicts the high concentrated plume in the metalimnion. The large amount of upwelling of finer suspended solid particles, and re-suspension of the sediments laden with phosphorus, are thought to have caused high concentration in the epilimnion and hypolimnion, respectively. Nevertheless, the model well reproduced the seasonal dynamics of both chlorophyll a and total phosphorus concentration. Also, the model tracked the interflow of high phosphorus concentration plume brought by the turbid discharge during the Asian summer monsoon season. Two different hypothetical discharge scenarios (discharge from epilimnetic, and hypolimnetic layers) were analyzed to understand the response of total phosphorus interflow plume on the basis of differential discharge gate location. The simulated results showed that the hypolimnetic discharge gate operation ($103{\sim}113\;m$) was the most effective reservoir structural control method in quickly discharging the total phosphorus plume (decrease of in-reservoir concentration by 219% than present level).

• 방사성폐기물학회지
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• 제2권3호
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• pp.219-230
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• 2004

Most of the low-level liquid radioactive wastes generated from PWR plants are classified into high or low total suspended solid(HTDS or LTDS), and into radiochemical and radioactive laundry waste. Although the evaporation process has a high decontami- nation ability, it has several problems such as corrosion, foam, and congestion. A new liquid waste disposal process using the ion-exchange demineralizer(IED), instead of the current evaporation process, has been introduced into the Yonggwang NPP #5 and 6. These two methods have been compared to understand the differences in this study. Aspects compared here were the released radioactivity amount of the liquid radioactive wastes, the dose of off-site residents, the decontamination factor, and the amount of the solid radioactive wastes. The IED system is designed to discharge higher radioactivity about 20% than the evaporating system, and the actual radioactivity released from the evaporating and IED system were 0.473mCi and 1.098mCi, respectively. The radioactivity released from the IED was 2.32 times higher than that of the evaporating system. The dose of off-site residents was $2.97{\times}10^{-6}$mSv for the evaporating system, and $6.47{\times}10^{-6}$mSv for IED. The decontamination factor(DF) of the evaporator is, in most cases, far lower than the lower limits of detection(LLD) with the Ge-Li detector. Due to the low concentration of the liquid wastes collected from the liquid waste system, the decontamination factor of IED is very low. Since there is not enough data on the amount of solid radioactive wastes generated by the evaporation system, the comparison on these two systems has been conducted on the basis of the design, and the comparison result was that the evaporating system generated more wastes about 40% than IED.