• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.407-417
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• 2011

Nowadays, the high land use, mainly used for urbanization, is affecting runoff loads of non-point pollutants to increase. According to this fact, increasing runoff loads seems like to appear that it contributes to high ratio of pollution loads in the whole the pollution loads and that this non-point source is the main cause of water becoming worse quality. Especially, concentrated pollutants on the impermeable roads run off to the public water bodies. Also the coefficient of runoff from roads is high with a fast velocity of runoff, which ends up with consequence that a lot of pollutants runoff happens when it is raining. Therefore it is very important project to evaluate the quantity of pollutant loads. In this study, I computed the pollutant loadings depending on time and rainfall to analyze characteristics of runoff while first flush storm water and evaluated the runoff time while first flush storm water and rainfall based on the change in curves on the graph. I also computed contribution ratio to identify its impact on water quality of stream. I realized that the management and treatment of first flush storm water effluents is very important for the management of road's non-point source pollutants because runoff loads of non-point source pollution are over the 80% of whole loads of stream. Also according to the evaluation of runoff loads of first flush storm water for SS, run off time was shown under the 30 minute and rainfall was shown under the 5mm which is less than 20% of whole rainfall. These are under 5mm which is regarded amount of first flush storm water by the Ministry of Environment and it is judged to be because run off by rainfall is very fast on impermeable roads. Also, run off time and rainfall of BOD is higher than SS. Therefore I realized that the management of non-point source should be managed and done differently depending on each material. Finally, the contribution ratio of pollutants loads by rainfall-runoff was shown SS 12.7%, BOD 12.7%, COD 15.9%, T-N 4.9%, T-P 8.9%, however, the pollutants loads flowing into the steam was shown 4.4%. This represents that the concentration of non-point pollutants is relatively higher and we should find the methodical management and should be concerned about non-point source for improvement on water quality of streams.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.309-309
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• 2011

지구온난화와 도시기후 변화에 대응하기 위해 자연의 생태적 기능을 복원하고 환경에 대한 오염부하를 저감하여 도시 환경의 건강성과 지속성을 높이기 위해 도심 내 물순환시스템(urban water circulating system)의 구축이 요구된다. 즉, 물순환시스템을 활용하여 도심 내 다양한 수원(생태하천/호수 유지용수, 하수처리수, 우수, 지하수 등)을 네트워크 및 통합 관리하여 도시 내 물순환의 건전성과 수자원의 재이용률을 향상시킬 수 있다. 이를 위해서 연중 발생량이 일정하고 막대한(66.4억톤/년, 2009년 기준) 하수처리수 방류수는 고도처리를 통해 수질이 양호하며 안정적인 대체 수자원으로 고려된다. 또한, 하수처리수의 재이용은 공공수역으로 배출되는 오염부하량의 총량 삭감 및 상수사용량의 절감과 수자원을 효율적으로 이용한다는 면에서 최근 재이용 사례가 증가하고 있는 추세이다. 그러나, 도심 내 친수공간(생태하천/호수)은 저류수량에 비해 유입수량이 적어 체류시간이 비교적 장시간이고, 이로 인해 부영양화가 쉽게 발생해 수질이 악화된다. 따라서, 본 연구에서는 하수처리수 재이용수를 도심 내 친수공간의 유지용수로 활용 시, 수질정화공정(응집 후 여과, 응집 후 여과+한외여과, 응집 후 여과+한외여과+역삼투 공정)이 친수공간 내 조류성장에 미치는 영향을 파악하기 위해, 하수처리수 재이용수 pilot plant의 수질정화공정별 유출수를 활용해 M. aeruginosa를 시험조류로 조류성장(growth kinetics)을 조사하였다. 조류는 $5\times104$ cells/mL의 초기 농도로 접종하여 배양하였으며, 조류성장에 직접적인 제한인자인 용존반응성인의 농도에 따른 성장속도를 Monod와 변형 Monod Kinetics를 이용해 반포화상수(Ks)와 최대 성장속도(${\mu}$max)를 산정하였다. 실험결과, 역삼투 공정을 제외한 다른 수질정화공정은 비록 영양염류가 80~90% 이상 제거되어 수계의 화학적 성상이 변하였으나 조류성장역학의 변화는 통계학적 (p=0.05)으로 유의할만한 수준은 아닌 것으로 판명되었다. 또한, 수리학적 체류시간이 2주 이상이 될 경우, 역삼투 공정을 제외한 수질정화공정 별 유출수에서는 조류의 과다성장으로 인해 부영양화가 발생하는 것으로 판명되었다. 결론적으로 하수처리수 재이용수를 친수용수로 활용시, 조류성장을 방지하기 위하여 용존반응성인의 농도를 중점적으로 관리하는 수질정화공정 및 유지용수 공급방안을 고려해야하는 것으로 판단된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.236-246
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• 2012

Hospital out-shopping by local patients has become more popular. In particular, many cancer patients have visited hospitals in the capital area to get better medical services regardless of how far the hospitals are from their home. However this kind of hospital out-shopping may discontinue medical treatment and cause a waste of medical resources including manpower. In addition, it creates additional economic and social expenses such as caretakers' transportation and lodging expenses. It is necessary to study patients who would take the medical treatment in Busan go to Seoul for better medical services are more satisfied based on objective data. For this, a questionnaire survey has been performed against 223 cancer patients who had a surgery in Busan and 187 patents who had an operation in Seoul. According to the survey, the patients who had an operation in the capital area(Group A) were more satisfied than the patients who had a surgery in Busan(Group B) in terms of convenience facilities, doctors' competence. However the Group A was very dissatisfied in terms of accessibility and satisfaction on overall medical services.

• Journal of Life Science
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• v.30 no.2
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• pp.129-136
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• 2020

For effective treatment of wastewater containing ammonium nitrogen (NH₄-N), AT2, AT9, and AT12 strains, having high total organic carbon (TOC) removal capability, and FN47, possessing excellent ammonia nitrogen removal capability present in the activated sludge in the aeration tank of food wastewater treatment plants, were isolated and identified. The cells of these isolated strains were used for microbial augmentation with FIW-1 in the defatted rice bran as a medium to treat industrial wastewater. The investigation of the cultural characteristics of these isolated strains in the aeration tank showed that the affinities for substrate of the isolated strains were extremely high, of which AT12 (Alcaligenes sp. AT12) was the highest among the isolated strains. Ammonium nitrogen removal efficiency in the food wastewater was 71% in the isolated strain FN47 (Microbacterium sp. FN47) treatment group. When only activated sludge was added in the lab scale pilot using food wastewater during continuous culture experiment, the TOC removal efficiency was 63%. Meanwhile, the removal efficiency of 92% was obtained when the microbial augmentation FIW-1 for wastewater treatment was applied. In addition, the chemical oxygen demand (COD) level from the effluent wherein microbial augmentation FIW-1 was input for the initial three days in the wastewater treatment site experiment showed a treatment rate of about 43%, which was increased to 62% after an elapse of 5 days.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.257-265
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• 2016

The purpose of this study was to develop a strainer that could protect a flow system by blocking the introduction of foreign substances into the pipe of industrial or architectural facilities. Strainers are installed at the front tip of valves, machines, or pumps in the piping line of clean water, oil, or gas. There are Y-type, U-type, and T-type strainers. The study identified problems with the Y-type strainers, develop a "C-type strainer with its inlet and outlet on a straight line" as a more improved new model, and compared them in functions in a full-scale strainer test. The study conducted a full-scale strainer test according to four situations at the flow laboratory of Korea Research Institute of Standards and Science by using the old Y-type strainer and C-type strainer 50A. The test results show that the C-type strainer had a higher capacity coefficient(Kv) than the Y-type one, recording 74.9% when there was no screen, 54.5% when there were no foreign substances in the screen, 54.2% when there was a 15% accumulation of foreign substances, and 52.4% when there was a 30% accumulation of foreign substances. The investigator conducted a test only with the 50A type due to the limitations of life-size strainers, but the results demonstrate that the C-type strainer had better flow characteristics than the Y-type one.

• Convergence Security Journal
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• v.15 no.5
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• pp.97-105
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• 2015

Technology Security, especially in knowledge-intensive society, is becoming the most important organizational activity for the long-term success of a firm. However, there is not sufficient empirical research of activities of technology securities and business performance. This is one of the reason why Korean firms are reluctant to invest their resources to the technology security. We have tried to empirically analyze the relationship between a market and technological characteristics, which is one of the important business environmental characteristics and the activities of technology securities of Korean business firm by taking three hypotheses related to this research and investigating 209 Korean firms. According to the statistical research, results of the analyses suggest that the market and technological characteristics have positive impact on the activities of technology securities. Also the activities of technology securities have positive impact on the performance of technology security. More specifically, the results suggest that the relationship between the competitiveness of market and technological excellency and the activities of technology securities is supported statistically. But, the reverse relationship between the easiness of market entrance and the activities of technology securities is supported statistically. Also, there is no moderating effect of firm size between the relationship between a market and technological characteristics and the activities of technology securities. Finally, the relationship between the activities of technology securities and the risk of technology leakage is supported statistically.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.140-147
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• 2011

We studied the influence of livestock waste leachate on oxidative damage and antioxidative responses in poplar clones in August which increase the demand of antioxidants because of high temperature and high light during this period. We measured ion leakage, antioxidant enzyme activities (APX, GR), and carotenoid contents. Oxidative damage and antioxidative responses by treated livestock waste leachate in poplar clones showed various results. We divided poplar clones into three groups using the criteria based on ion leakage which represent cell damage induced oxidative stress. Eco 28, 62-10, Bonghwa1 and Dorskamp belonged to the first group in which the cell damaged level was lower than that of the control. The results suggest that this group augmented for demand of antioxidative in summer because high concentration of nitrogen induced by treatment of live stock wastes acted as environmental stress. Consequently, they failed to keep up the homeostasis of reactive oxygen species. The second group in which the cell damaged level was similar to that of the control was Suwon, 72-30 and 72-31 clones. Finally, 97-18 clone belonged to the third group in which the cell damaged level was lower than that of the control group. In this case, nitrogen treated by livestock waste leakage decreased oxidative stress. 97-18 clone was the clones with the least damage in summer oxidative stresses treated by livestock waste leakage. These results suggest that the high concentration nitrogen due to the livestock waste leakage can act differently upon the clones. We speculate that the added oxidation damage in the summer (growing season) may have an effect on the total fresh weight and also influence the purification ability for livestock waste leakage. However, further studies are needed for the confirmation.

• KSBB Journal
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• v.16 no.2
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• pp.133-139
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• 2001

To treat piggery wastewaters containing refractory compounds including nitrogen, biological treatments were investigated. In biological treatment, the removal efficiencies of organics and nitrogen by the activated sludge process and bioreactor using a BACC (Biological Activated Carbon Cartridge) media filled with granular activated carbon were examined. The results were as follows; in the biological process, when the approximate influent BOD concentration of 620 mg/L, through dilution, was treated by the activated sludge process, the process should be operated at a HRT of over 8 days to maintain an effluent BOD concentration of lower than 100 mg/L. In the treatment of piggery wastewater using a BACC bioreactor, when the HRT was 200 hours, the BOD, COD(sub)cr, and TKN removal efficiency of the effluent were 94, 75 and 64.3%, respectively. Comparing the BACC bioreactor with the activated sludge process, when the volumetric loading rate was 0.3 g BOD/L.day, the specific substrate removal rate of BOD was 0.14 g BOD removed/L.day in the activated sludge process which compared with 0.27 g BOD removed/L$.$day in the BACC bioreactor. The BACC bioreactor showed on average a 2-fold higher removal rate and was superior to the activated sludge process in wastewater treatment in terms of variations of loading time and high loading time. Therefore, the BACC process can effectively treat piggery wastewater containing high concentrations of nitrogen and organic compounds.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.642-642
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• 2012

최근에 들어 지구온난화에 따른 기후변화의 영향으로 국지성 집중호우와 돌발성 호우가 한반도 뿐 아니라 전 세계적으로도 많이 나타나고 있고, 그로 인한 이상홍수의 발생이 우리나라의 인명 및 재산피해를 날로 증가시키고 있는 추세이다. 그러나 현재 국내의 홍수방어시스템은 정확도 및 선행시간 확보 등의 측면에서 국민들의 요구수준까지는 그 역할을 수행하지 못하고 있는 실정이다. 또한 최근 4대강 살리기 사업을 통해 수행된 보 설치 및 하도 준설로 인해 하천환경의 변화가 크게 발생하여, 보다 정확하고 신속한 홍수위 예측기법이 요구되고 있는 실정이다. 이에 따라 현재 4대강 홍수통제소에서는 정확한 홍수위예측을 위해 4대강 본류 및 주요 지류에 대해 수리모형을 구축하고 있고, 기존의 저류함수모형에 의한 강우-유출 해석기법을 적용하여 주요 지류에 대한 유입량을 산정하기 위한 모형을 구축중에 있다. 국내 홍수방어 시스템에 현재까지 사용되어 오고 있는 저류함수모형 및 수위-유량 관계식을 이용한 방법은 물리적 기반의 홍수예측모형으로 유역의 지형학적 인자와 그에 따른 여러 변수를 포함하기 때문에 하천환경의 변화로 인해 각각의 추적과정에서 오차들이 발생하여 해석결과에 영향을 미치는 단점이 있다. 이에 반해 데이터 기반 모형은 강우-유출 모형에서 사용되는 많은 수문학적 자료 및 매개변수들의 사용 없이 오직 수위 및 강우측정 자료만을 이용하여 홍수를 예측하는 모형이다. 본 연구에서는 낙동강 유역에 대해 보다 정확한 홍수위 예측을 위해 현재 낙동강홍수통제소에서 구축중인 낙동강 본류의 수리모형의 주요 지류의 유입량 산정을 위해 기존의 물리적 기반 모형이 아닌 뉴로-퍼지(Neuro-Fuzzy) 모형을 이용한 data 기반 모형을 적용해 기존 물리적 기반 모형과 비교 분석 하고자 하였다. 낙동강의 주요지류인 감천, 금호강, 남강, 내성천, 밀양강, 반변천, 위천, 황강을 적용유역으로 선정하여 유역별로 티센망을 구축하였고, 각 지류별로 수위관측소를 선정하여 최근 10년동안 낙동강유역의 홍수예 경보가 발령되었거나 많은 비가 온 사상을 선정해 모형을 검증하였다. 모형은 실시간 수위측정 자료와 강우자료 및 해당유역 댐의 방류량 자료를 이용해 유역별 최적 입력자료 조합을 선정하여 간단하게 구축할 수 있었다. 또한 10분 단위 및 30분 단위의 입출력 자료로 모형을 구축하여 비교하였다. 이번 연구에서 수행한 낙동강유역에서의 뉴로-퍼지(Neuro-Fuzzy) 모형을 이용한 홍수예측기법을 통해 몇가지 data만으로 유역의 주요지점에 대한 홍수위와 홍수량을 예측할 수 있음을 확인할 수 있었다. 모의 결과는 실측치와 비교해 정확도 면에서 우수함을 보여 주었으나 예측시간이 길어질수록 실측치의 경향을 벗어나는 결과를 보였다. 그러나 실시간 홍수예 경보에 있어서는 만족할만한 선행시간을 확보할 수 있었다. 구축된 Data 기반 모형이 물리적 기반 모형과 더불어 낙동강 홍수예 경보를 위한 모형으로 사용될 수 있다면 보다 효율적인 예 경보 체계 구축에 도움을 줄 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.176-176
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• 2017

배수시설 내 맨홀에서의 과부하 흐름은 관거시설의 배수 능력을 저하시켜 우수의 역류로 인한 도시 침수피해의 가중 요인이 된다. 특히, 도시 유역 중 하류부의 저지대에서 주로 설치되는 합류 맨홀은 저지대 침수에 많은 영향을 미치므로 합류맨홀에서의 흐름특성 분석 및 유입유량 변화에 따른 손실계수의 변화에 관한 연구가 필요한 실정이다. 현재까지 중간맨홀, $90^{\circ}$ 접합맨홀 및 3방향(T형) 합류맨홀 등에 관한 연구는 지속적으로 수행되고 있으나 4방향 합류맨홀에 관한 연구는 기초적인 연구만 수행되고 있다. 4방향 합류맨홀은 세 개의 유입관과 한 개의 유출관으로 구성되어 있으므로 각 유입관의 유입유량 변화에 따라서 맨홀에서의 손실계수가 다양하게 변화된다. 이와 같은 유입유량 변화에 따른 맨홀 내 흐름특성 분석 및 손실계수 산정에 관한 연구는 국내에서는 전무한 실정이다. 그러므로 유입유량 변화에 따른 4방향 합류맨홀에서의 손실계수 변화특성의 분석이 필요하다. 본 연구에서는 4방향 사각형 합류맨홀에서 세방향에서 유입되는 각 유입유량의 유입비($Q_{in}/Q_{out}$)가 0.0~1.0으로 변화하는 조건에서 평균 손실계수를 산정하기 위하여 하수도시설기준(환경부, 2011)의 표준 1호 맨홀 및 연결관경을 1/5로 축소하여 수리실험 장치를 제작하였다. 유출유량은 $3{\ell}/sec$이고 각 유입관(주유입관 및 좌 우측면유입관)의 유입유량을 $0{\sim}3{\ell}/sec$까지 유입유량의 비율을 각각 10%씩 변화시키면서 수리실험을 실시하였다. 실험결과 주관거의 유입유량이 줄어들고 측면관거의 유입유량이 늘어나면서 손실계수가 상승하는 것으로 나타났으며, 한쪽 측면 관거에서만 유입유량이 들어오는 $90^{\circ}$ 접합맨홀의 형태에서 손실계수가 가장 크게 나타났으며, 유입유량 변화에 따른 4방향 합류맨홀에서의 손실계수의 범위는 0.5~1.7으로 산정되었다. 이는 과부하 4방향 사각형 합류맨홀에서는 측면 유입관에서의 유입유량의 증가에 따라 평균 손실계수 값이 크게 증가되는 것으로 판단된다. 이는 김정수(2010) 등이 산정한 $90^{\circ}$ 접합맨홀의 손실계수 및 중간맨홀의 손실계수와 유사하게 나타났으므로 전체적인 손실계수의 범위는 타당하다고 판단된다. 또한, Wang(1988) 등의 유사연구와의 유입유량 변화에 따른 손실계수의 변화 경향도 유사하였다. 따라서 본 연구에서 산정된 유입유량 변화 조건이 고려된 4방향 합류맨홀에서의 손실계수는 XP-SWMM 등의 부정류 흐름이 고려된 도시지역의 침수해석이나 관거 배수능력 평가에 활용이 가능할 것으로 판단된다.