• Journal of Korean Society of Environmental Engineers
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• v.32 no.5
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• pp.469-476
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• 2010

The purpose of the study is to find ways to decrease turbidity and residual aluminum by improving the efficiency of coagulation process through controlling the pH of the source water with $CO_2$ when the pH increases by algal bloom or by the characteristics of the source water. Water quality parameters were monitored before and after $CO_2$ addition in February, March, April, and December, when the pH of the source water is over 8.0 and constant regardless of day and night. Water quality parameters closely related with evaluation of treated drinking water quality were monitored in detail, e.g. aluminum, turbidity, particle counts, TOC, THMs, 2-MIB, and geosmin. According to the results, inorganic water quality parameters such as turbidity, particle counts, and aluminum were decreased due to improved efficiency of the coagulation process. It was concluded that the pH of the water in the arrival basin must be controlled below 7.4 by adding $CO_2$ when the pH of the source water increasing. By controlling pH with $CO_2$, the water quality could be maintained within the drinking water quality goal of Seoul City (<30 particle/mL of particle count, <0.05 NTU of turbidity and <0.02 mg/L of aluminum). The change of the pH could not affect the concentrations of DBP's (e.g., THMs, CH, and HAAs) and taste/odor causing compounds (e.g., 2-MIB and geosmin). 2-MIB and geosmin were affected more by their initial concentrations in the source water.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.4
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• pp.330-348
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• 2007

Soil problems and agricultural water management of the reclaimed land in Korea were reviewed through research results conducted in RDA and ADC. According to the Korean Soil Classification and Soil Survey(NIAST, 2002), the 5 soil orders with the 45 soil series were distributed on the fluvio-marine or marine deposit of the west and south coastal plains. Yeompo, Munpo, Hasa, Gwangwhal, and Poseung soil series were most commonly distributed soil on the fluvio-marine deposits, associated with tideland of the sea coast. Former 4 soils were Entisols, and the latest one was the Inceptisols. Buyong soil associated with Poseung series was an Alfisols. Extent of Myeongji soil, a Molisols, and Yongho soil, a Histosol, were minor. Salinity control and management problems were closely related with high water table and low percolation rate due to plow-pan layer developed during the leaching process in the silty textured soil. For evaluation of field salinity, use of an electromagnetic inductance, EM38, with GPS was helpful to understand salinity status and field variability. Deep plowing, subsoiling and drainage improvement by tile drainage might be effective in paddy with plow-pan. New technology such as variable rate fertilization might save fertilizers and thus reduce environmental impact of agriculture on water quality. Water quality of agricultural water resources in reclaimed land was less adequate than that of inland water resources. Proper crop management is necessary depended upon quality for crop growth as well as to match with water quality target.

• Journal of the Korean Society of Urban Environment
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• v.18 no.4
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• pp.401-408
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• 2018

EQPS (Effluent Quality Prediction System, Dynamita, France) was applied to analyze the appropriateness of the design of a bioreactor in A sewage treatment plant. A sewage treatment plant was designed by setting the design concentration of the secondary clarifier effluent to total nitrogen and total phosphorus, 10 mg/L and 1.8 mg/L, respectively, in order to comply with the target water quality at the level of the hydrophilic water. The retention time of the 4-stage BNR reactor was 9.6 hours, which was 0.5 for the pre-anoxic tank, 1.0 for the anaerobic tank, 2.9 for the anoxic tank, and 5.2 hours for the aerobic tank. As a result of the modeling of the winter season, the retention time of the anaerobic tank was increased by 0.2 hours in order to satisfy the target water quality of the hydrophilic water level. The default coefficients of the one step nitrification denitrification model proposed by the software manufacturer were used to exclude distortion of the modeling results. Since the process modeling generally presents optimal conditions, the retention time of the 4-stage BNR should be increased to 9.8 hours considering the bioreactor margin. The accurate use of process modeling in the design stage of the sewage treatment plant is a way to ensure the stability of the treatment performance and efficiency after construction of the sewage treatment plant.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1997.12a
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• pp.81-90
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• 1997

위해성평가 방법론이란 환경오염으로 인해 유발될 수 있는 인체의 위해성을 정성또는 정량적으로 추정하여 구체적이고도 과학적으로 평가하고자 하는 방법론으로서, 단순히 환경중 오염도를 위해도(risk)로써 알기 쉽게 수치적으로 제사하는 과정만이 아니라 오염물질의 발생에서부터 인체로의 영향까지를 통계학적, 동성학적, 수학적, 사회정책 및 경제학적 측면 등을 모두 고려하여, 정책 결정자들과 일반대중이 과학적 기반 위에서 합일점을 찾도록 하는데 과학적 근거로 제시될 수 있는 방법론이다. 과거에는 환경오염에 의한 피해의 유무, 즉 인간관계를 규명하는 것이 일차적 관심의 대상이었으나 구체적이고 정량적인 정보를 요구하는 현대 사회에서는 오염피해의 정도와 심각성을 평가하여 주민들에게 알려주어야 하며 어느 정도의 오염수준을 우리 사회에서 받아들일 수 있는가의 판단이 매우 중요한 문제로 떠오르게 되었다. 또한 복잡 다기화 되어 가고 있는 사회현상 속에서 이해관계와 불확실성으로 얽혀 있는 환경문제를 풀어나가기 위해서는 과학적이고 합리적인 방법론이 요구되고 있으며 이러한 방법론들이 환경관리정책의 기본이 되고 있음을 미국등 선진국의 예를 보아 알 수 있다. 위해성 평가의 필요성은 첫째, 환경오염 심화에 따른 인체건강영향에 대한 관심이 증대되었으며 둘째. 사회적 행정적으로 독성정보의 정량화 필요성이 대두되었고, 셋째, 현실성 있는 오염관리와 넷째. 기준치 제정, 제도시행 전후의 비용효과분석이 가능하다는 점들이다. 위해성 평가를 통하여 환경오염의 인체영향에 대한 종합적이고 계량적인 정보가 제공될 수 있어 국민, 정부, 기업 등 각 주체간의 의사 교환이 수월해지고 국민의 신뢰 회복에 기여할 수 있으며 수질 등 오염에 대한 합리적 기준을 제시할 수 있고 이에 따른 공학적 처리기술 목표 설정을 가능케 한다. 본 원고의 환경오염물질의 위해성 평가에 대한 방법론은 주로 미국 환경보호청의 자료 (US EPA, 1993)와 NAS(National Academy of Sciences, 1983), 미국에서 발행되는 정부 지침서 (Federal Register)에 고시된 내용 등을 토대로 하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.462-462
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• 2021

최근 도시화 및 불투수면의 증가와 지하수의 과다한 사용으로 직접유출이 증가하고, 침투량이 감소하며, 하천의 건천화가 발생하고 있다. 이에 환경부에서는 이러한 물순환의 왜곡을 막기위해 물환경보전법상의 물순환율을 정의하고 물순환 관리목표를 설정하였다. 하지만 지역 별 물순환 특성을 반영한 관리계획이 부족하고, 현재 제한된 재원의 효율적 활용을 위해서는 물순환 관리지역에 대한 우선순위 결정도 필요하다. 본 연구에서는 PSR framework를 통해 유역 물순환 평가방법론을 만들고 이를 활용한 지역별 관리계획 및 우선순위를 결정하고자하였다. PSR framework는 지속가능성을 위해 OECD가 개발한 개념 모형이며, Pressure, State, Response 세 가지 요소로 구분해 평가하게된다. PSR framework의 기본 개념은 인간의 활동들이 환경에 압력 (P)를 주고, 이로 인해 자연의 질과 영향 (S)을 미치며, 이에대한 회복을 위해 인식과 행동을 통해 정책과 제도 등을 통해 반응 (R)한다는 것이다. 유역 물순환을 4가지 그룹 (기후, 수문학적, 사회경제학적, 환경적)으로 구분하고 각 그룹 별 평가요소에 대하여 도출하였다. 기후그룹은 강우, 수문학적 그룹은 증발산, 토지이용, 유출특성을, 사회경제학적 그룹은 재정, 사회구조, 기반시설, 정책을, 환경적 그룹은 수질, 수생태계를 선정하였다. 이후 각 요소 별 평가를 위해 다양한 지표를 고려하여 선정하였으며, 각 지표를 PSR framework에 맞춰 재분류하였다. 각 지표를 하나의 점수로 통합하기 위해 지표 별 가중치를 산정하였으며, 이때 연구자의 주관이 반영되지않는 엔트로피 기법을 이용하여 산정하였다. 구한 식을 통해 우리나라 소유역구분을 기준으로 모든 지표를 계산하였으며, 각 지표에 가중치를 적용해 유역 종합점수를 산정하고 유역 별 취약지역 및 취약요소를 평가하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.499-499
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• 2022

급격한 도시화와 이로인한 불투수면의 증가는 유역의 물순환을 왜곡시키고 있다. 직접유출의 증가와 침투량 감소로 이어지며 이는 지하수 함유량의 감소와 하천건천화를 유발한다. 환경부는 더 이상의 물순환 왜곡을 막기위해 물환경보전법상의 물순환율을 정의하고 물순환 관리목표를 설정하였으며, 제3차 강우유출 비점오염원관리 종합대책에서 물순환 사업 추진을 위한 소권역 별 우선순위산정을 과제로써 제시하고 있다. 대표적인 물순환 사업은 저영향개발기법 설치이다. 저영향 개발기법은 토지 및 공간을 이용해야하기 때문에 설치비용이 높고 위치선정에 제약이 많으며 유지관리도 어렵다. 이에 물순환 사업에는 단순 불투수면 뿐만아니라 사회, 경제적 요소까지 고려하여야한다. 본 연구에서는 물순환 우선순위를 산정하기위해 불투수면뿐만 아니라 사회, 경제적 요소까지 고려한 종합적인 우선순위를 산정하였다. 유역 물순환 평가를 위해 PSR framework을 이용하였다. PSR framework는 OECD가 개발한 지속가능성 평가 개념이며, Pressure, State, Response 세 가지 요소로 구분해 평가하게된다. PSR framework의 기본 개념은 인간의 활동들이 환경에 압력 (P)를 주고, 이로 인해 자연의 질과 영향 (S)을 미치며, 이에대한 회복을 위해 인식과 행동을 통해 정책과 제도 등을 통해 반응 (R)한다는 것이다. 본 연구에서는 PSR framework의 평가요소 Pressure는 불투수면 및 강우, State는 물순환, 하수관거, 수질, 수생태계, Response는 협력, 인식, 재정, 토지로 구분하여 평가하였다. 최종적으로 불투수면적 감축 대상 소권역('30년 무대책 불투수면적률 25% 이상)소권역에 대하여 최종우선순위를 산정하였다.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.25-31
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• 2011

In this study, model-based $NH_4-N$ predictive control algorithm by using influent pattern was developed and evaluated for effective control application in $A^2/O$ process. A pilot-scale $A^2/O$process at S wastewater treatment plant in B city was selected. The behaviors of organic, nitrogen and phosphorous in the biological reactors were described by using the modified ASM3+Bio-P model. A one-dimensional double exponential function model was selected for modeling of the secondary settlers. The effluent $NH_4-N$ concentration on the next day was predicted according to model-based simulation by using influent pattern. After the objective effluent quality and simulation result were compared, the optimal operational condition which able to meet the objective effluent quality was deduced through repetitive simulation. Next the effluent $NH_4-N$ control schedule was generated by using the optimal operational condition and this control schedule on the next day was applied in pilot-scale $A^2/O$ process. DO concentration in aerobic reactor in predictive control algorithm was selected as the manipulated variable. Without control case and with control case were compared to confirm the control applicability and the study of the applied $NH_4-N$control schedule in summer and winter was performed to confirm the seasonal effect. In this result, the effluent $NH_4-N$concentration without control case was exceeded the objective effluent quality. However the effluent $NH_4-N$ concentration with control case was not exceeded the objective effluent quality both summer and winter season. As compared in case of without predictive control algorithm, in case of application of predictive control algorithm, the RPM of air blower was increased about 9.1%, however the effluent $NH_4-N$ concentration was decreased about 45.2%. Therefore it was concluded that the developed predictive control algorithm to the effluent $NH_4-N$ in this study was properly applied in a full-scale wastewater treatment process and was more efficient in aspect to stable effluent.

• Korean Journal of Environmental Biology
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• v.33 no.4
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• pp.425-432
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• 2015

Pollution in the fresh water system in urban area has the adverse effect on the amphibians population. Restoration activity of amphibian in the urban stream has been growing in Korea as well as western country. For successful restoration water quality of urban stream should be sufficient for survival and normal development of amphibian. To monitor the biological safety of surface water in the Tancheon basin, the capital area of Korea, a 6-day exposure Bombina orientalis embryo developmental toxicity assay was examined. The toxicity of surface water of Tancheon mainstream were lower than those of tributaries of Tancheon. The survival rate of embryos negatively correlated with total dissolved solid, turbidity and electrical conductivity whereas the developmental abnormality and growth retardation of embryos was positively correlated with total dissolved solid, turbidity and electrical conductivity. An amphibian developmental toxicity assay would be helpful for the selection of point for construction of habitat and reintroduction of amphibian in interrupted urban stream.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.345-356
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• 2011

Based on the consideration of land based pollutant discharges from the basin and seawater quality related carrying capacity and the seawater quality improvement in receiving water bodies of Yeoja Bay where eutrophication and organic pollution are in progress, were evaluated. The permissible inflow loads of BOD, TN and TP by using the geographical features and box modelling method were estimated. As results, it is shown that the reduction rate of discharged BOD and TP loads were 39.3% and 30.8 %, respectively, however, 6.9% was estimated for TN. According to the pollutant loading in each tributary and generated load of the basin, it is given much weight on the land use group, and also was shown in discharged load estimation. This suggests that it is important to control nonpoint source pollutant such as livestock and land use groups as well as point source to contribute the proposition of the water quality improvement plan according to the characteristics of the bay.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.655-663
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• 2017

It is difficult to manage hotspot area and to establish the reduction plan considering with spatial-distribution on Korea TMDLs (Total Maximun Daily Loads) system. To solve this problems, methods of Load Duration Curve (LDC) using long-term flow and water quality data, and spatial-analysis were applied on present TMDLs. Jinwi A watershed which is enforced TMDLs plan were selected to study area. Results of application of suggested methods in this study to Jinwi watershed, Hwangguji tributary was selected to hotspot area and Jinwi tributary was exclued. Also, middle area of Hwangguji tributary was needed a reduction plan for the protection of non-point source pollution. In downstream area, livestock manure should be managed additionally. The new methods suggested in this study were useful to increase healthiness for total watershed.