• 신재생에너지
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• 제5권3호
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• pp.32-39
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• 2009

The Samcheonpo ocean small hydropower plant (SHP) has a special feature of using marginal hydraulic head of circulating water system of fossil fuel power plant as a power source and having the characteristics of general hydropower generation and tidal power generation as well. Also, it contributes to reducing green house gases and developing clean energy source by recycling circulating water energy otherwise dissipated into the ocean. The efficiency of small hydropower plant is directly affected by effective head and flow rate of discharged water. Therefore, the efficiency characteristics of ocean hydropower plant are analyzed with the variation of water level and flow rate of discharged water, which is based on the accumulated operation data of the Samcheonpo hydropower plant. After the start of small hydropower plant operation, definite rise of water level was observed. As a result of flow pattern change from free flow to submerged flow, the instability of water surface in overall open channel is increased but it doesn't reach the extent of overflowing channel or having an effect on circulation system. Performance evaluation result shows that the generating power and efficiency of small hydropower exceeds design requirements in all conditions. Analysis results of CWP's water flow rate verify that the amount of flowing water is measured less and the highest efficiency of small hydropower plant is achieved when the effective head has its maximum value. In conclusion, efficiency curve derived from water flow rate considering tidal level shows the best fitting result with design criteria curve and it is verified that overall efficiency of hydropower system is satisfactory.

• 한국항만학회지
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• 제13권1호
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• pp.133-146
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• 1999

Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.

• 한국수자원학회논문집
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• 제42권8호
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• pp.631-641
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• 2009

본 연구는 부영양화되어 있는 하구감조역에서의 $N_2O$생성과 거동을 파악하는 것을 목적으로 도시역에서의 N2O발생에 착안하여 그 중에서도 인위적 임팩트가 크다고 판단되는 하수처리수 생활폐수 등이 유입되는 도시하천감조역을 대상으로 현지 정점조사를 실시하여 수역의 사계절에 걸친 각 질소성분의 농도변화와 flux를 상세히 파악하고 저질간극수 중의 연직분포를 측정하였다. 그 결과, 완혼합이고 염수쐐기설(楔)가 형성되는 Tatara천(川)에서 하수처리수는 해수의 혼합형태의 영향을 크게 받고 고농도수괴(水塊)로서 표층을 이동하고 있으며, 이 수역의 질소변환기구 및 $N_2O$생성과정에 큰 영향을 미치고 있는 것이 밝혀졌다. 이 수역에서 관측된 $N_2O$농도는 1.8-20.9 $\mu M$로서 대기중의 포화농도와 담수중의 포화농도를 고려하면 항상 포화농도상태이며, 주발생원은 수역저토였다. 저질간극수 중의 각 질소성분의 농도분포는 호소와 인근해역에서의 분포와는 달리 분자확산 이외의 수송경로가 있다는 것이 시사되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1463-1474
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• 2008

In order to investigate stabilization effect and sustainability on As-contaminated farmland soils which were affected the abandoned mine site and stabilized by zerovalent iron(ZVI) and industrial by-products, batch-scale and pilot-scale tests were carried out. In batch tests, ZVI and industrial by-products(blast furnace slag, steel refining slag and oyster shell powder) were used in treatment materials to reduce the As leaching. Industrial by-products were mixed with As-contaminated soils, in the ratio of 1%, 3%, 5% and 7% on the weight base of dried soil. The results of batch-scale tests was shown that the reduction of As concentration was observed in all samples and it was expected that ZVI and steel refining slag were more effective than other treatment materials to stabilize As compounds. In pilot-scale tests, columns were filled with untreated soils and treated soils mixed with ZVI and steel refining slag in the same mixing ratio of 3%. Distilled water was discharged into the columns with the velocity of 0.3 pore volume/day. During the test, pH, EC, Eh and As concentration were measured in the regular term(1pore volume). after six months, pilot-scale tests were retested to investigate sustainability of treatment materials. As a result, It was shown that the leachate from control column was continuously released during the test period and its concentration was greater than $100ug{\cdot}L^{-1}$ which was exceeded the national regulation of water discharged to river or stream ($50ug{\cdot}L^{-1}$). On the other hand, soil treated with ZVI and steel refining slag showed that the concentrations of leachate were lower than national regulation of water discharged to river or stream. Therefore it was expected that ZVI and steel refining slag could be applied to the farmland site as the alternative treatment materials.

• 한국해양환경ㆍ에너지학회지
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• 제18권4호
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• pp.274-281
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• 2015

국내 연안에 위치해 있는 화력 및 원자력 발전소는 발전시설 냉각을 위해 해수를 사용한다. 입구를 통해 배출되는 온배수는 유량이 상당하여 입구 근처에 큰 운동에너지가 존재한다. 이러한 제한된 입구에서 빠른 흐름이 존재하는 제트류 영역에 설치된 수직축 터빈의 성능을 수치적으로 조사하였다. 제트류 영역에서 입구와 터빈간 거리, 입구 직경과 수직축 터빈의 직경에 따른 성능 변화를 TSR=3.0에서 조사하였다. 또한, 입구가 1개인 경우와 2개인 경우에 대해 직경이 다른 터빈을 배치하여 성능 및 발전량을 비교하였다. 입구가 1개인 경우 입구로부터 터빈과의 거리가 증가함에 따라 터빈 효율이 감소함을 알 수 있었고, 터빈 직경과 입구 직경이 동일할 때 효율이 가장 좋은 것을 알 수 있었다. 입구가 2개인 경우는 효율 및 총 발전량을 고려하여 입구와 동일한 크기의 터빈을 각각 배치하는 것이 좋은 것을 확인하였다. 본 연구는 방수로 입구 전방에 설치된 수직축 터빈을 개념적으로 설계하는데 활용될 수 있을 것으로 기대된다.

• 자원리싸이클링
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• 제10권5호
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• pp.36-43
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• 2001

The chlorine component in fly ash from municipal solid waste incineration ash was removed by water washing for the purpose of recycling fly ash as a raw material of ordinary portland cement. The samples were a different kind of 리y ashes using $Ca(OH)_2$and NaOH as media of wet scrubber for flue gas cleaning. The content of soluble salts of fly ash using $Ca(OH)_2$and NaOH was 32.8%, 50.1% and the content of chlorine component, 22.9% and 26.0% respectively, which was KCl, NaCl, CaC1OH mainly. When each fly ash was washed using water under conditions of a agitation speed of 300 rpm, a liquid to solid ratio of 10, most soluble salts in fly ash were dissolved within 30 minutes and the content of chlorine component in ash was diminished to the content of 4.4%, 2.O% at $20^{\circ}C$ and 1.7%, 0.8% at $50^{\circ}C$ respectively. And the main compound of residual chlorine component in ash after water washing was friedel`s salt ($3CaO.A1_2$$O_3$.$CaCl_2$.$10H2$O). From analysis results of water quality for wastewater by water washing, the components exceeding discharged wastewater standard were only Pb and Cd. But As pH was controlled to 10 with addition of $CO_2$(g) or $Na_2$$_CO3$in water, the concentration of heavy metals such as Pb and Cd was also under discharged wastewater standard.

• 기술사
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• 제34권2호
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• pp.46-51
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• 2001

It Is not uncommon to see some reports that livestock wastes are discharged into land, streams or seas without any treatment in the protective area of water resource. This study reports the development of the technique of protecting water resources through making use of treated livestock in organic farming after the procedures of collecting livestock wastes in 100% water tight PDF tanks, mixing Pedac, etc and fermenting. This techinque makes organic farming products possible without experiencing soil acidification caused by chemical fertilizer.

• 한국물환경학회지
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• 제23권1호
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• pp.144-154
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• 2007

The acute and chronic toxicity of ambient and effluent water discharged to Lake Shihwa were investigated by using Vibrio fischeri, Daphnia magna and Oryzias latipes. Physicochemical characteristics including biochemical oxygen demand (BOD) and nine heavy metals in a total of 15 water samples were evaluated and were satisfied with relevant Korean Water Quality Standards (KWQS) except for Hg in one sample. Acute toxicity was observed in five samples collected from three sampling locations. When impacts on reproduction and growth after chronic exposure were evaluated with D. magna, all the samples showed significant chronic effects. Reproduction appeared relatively more sensitive endpoint. In 21 days chronic tests on O. latipes, survival, mean egg number per female per day, hatching success rate and time to hatch were affected by increasing sample concentration. The organ-level changes such as gonadosomatic index (GSI), and hepatosomatic index (HSI), and molecular biomarker of vitellogenin (Vtg) induction that evaluated with O. latipes increased as exposure concentrations increased. It is noteworthy that the samples that did not exceed the KWQS resulted in acute and chronic toxicities. The results suggested that numeric criteria based on physicochemical parameters may not be protective of aquatic ecosystem. Acute and chronic toxicity tests with organisms representing different trophic groups should be supplemented in order to provide adequate level of environmental protection.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.409-411
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• 2008

Water conveyance from waste water treatment plant can play a role in securing river water quantitatively in urban watershed, but it can also cause more severe contamination of river water due to lack of water quality management. Soil aquifer treatment(SAT) has been introduced to overcome the worsening water quality in the water conveyance system considering the characteristics of Korean urban watershed. The application of SAT to the water conveyance system not only improve water quality of ordinarily discharged water but also prevent accidential water pollution to the urban watershed. Since most domestic urban watersheds are consist of narrow terrace lands and surrounded by roads, SAT is estimated not to be appropriate to the urban watershed with respect to the quantitative efficiency. However, since the upstream of urban watershed in which discharge ports are located usually consists of agricultural lands, SAT can be applied near discharge ports. Therefore, combination of water conveyance and SAT is expected to supply clean and safe river water in urban watershed.

• 대한환경공학회지
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• 제28권6호
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• pp.654-660
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• 2006

본 연구에서는 대전천에 위치한 오정천지역의 소유역을 대상으로 CSOs 배출특성에 관한 모델링을 실시하였다. SWMM을 이용하여 대상유역에서 $2001{\sim}2004$년까지의 연간 유량, 수질, 및 부하량 변화에 대하여 모의를 실시하였다. 모의결과에 의하면, 강우에 의해 발생된 SS 유출부하량은 강우가 집중되는 $7{\sim}8$월에 가장 높게 나타났으나, 이때 강우의 증가에 비하여 부하량의 증가는 크지 않았는데 이는 강우가 잦은 $7{\sim}8$월에는 짧은 건기일수로 인하여 유출수의 SS농도가 낮아졌기 때문이다. $2001{\sim}2004$년 동안의 유량과 수질을 기초로 유출부하량을 산정한 결과 SS가 연간 하천에 미치는 부하량은 건기에 9.3%, 우기에 90.7%로 우기시에 미치는 영향이 매우 큰 것으로 나타났다. 우기시에 우수토실에서 월류를 통해 유출되는 CSOs는 38.4%, 차집관거로 차집 되어 하수처리장 방류구를 통해 방류되는 부분은 61.6%로 산정되었다.