• 한국물환경학회지
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• 제28권2호
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• pp.255-268
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• 2012

Nonpoint source pollution has become a concern for water quality in the Han River system, especially during the high runoff events during the monsoon season. The patterns in nonpoint source runoff the relationships with land use, rainfall intensity, and stream nutrients concentrations were surveyed in 19 streams in the Han River watershed. The results show that the magnitude of NPS inputs of nutrients and sediment in the Han River watershed are of a serious concern. In the South Han River watershed, event mean concentrations (EMC) for biochemical oxygen demand (BOD), suspended sediment (SS), dissolved organic carbon (DOC), dissolved total phosphorus (DTP), total nitrogen (TN) Nitrate ($NO_3$-N) and total phosphorus (TP) were $1.94mg{\cdot}L^{-1},\;251mg{\cdot}L^{-1},\;2.75mg{\cdot}L^{-1},\;0.076mg{\cdot}L^{-1},\;2.82mg{\cdot}L^{-1},\;2.40mg{\cdot}L^{-1}$ and $0.232mg{\cdot}L^{-1}$, respectively. In the North Han River watershed, EMCs for BOD, SS, DOC, DTP, TN, $NO_3$-N and TP were $1.34mg{\cdot}L^{-1},\;172mg{\cdot}L^{-1},\;2.63mg{\cdot}L^{-1},\;0.032mg{\cdot}L^{-1},\;1.97mg{\cdot}L^{-1},\;1.55mg{\cdot}L^{-1}$ and $0.148mg{\cdot}L^{-1}$, respectively. The specific export coefficients of nutrient and sediments were much higher than those of other reports. Our study also found that the proportion of agricultural field area was significantly correlated with the EMCs for nutrients. Therefore, efforts to reduce NPS loading must focus on agricultural practices in the watershed. The relationships between land use and nutrient and sediment export found in this study can be used to derive estimates of runoff coefficients for agricultural field and as input data for modeling works and to develop total maximum daily load and best management practices in the Han River watershed.

• 상하수도학회지
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• 제25권6호
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• pp.825-837
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• 2011

Seonakdong river consists of stagnant sections whose flowrate is controlled by the Daejeo and Noksan gates. As a result, there is not a minimum flow during normal times. The Daejeo and Noksan gates are located at the upstream head and the downstream end of Seonakdong river, respectively. Seonakdong river is an estuarine tributary of Nakdong river, which is a reservoir-like river used for agricultural irrigation, with the gate at the estuary of the river to prevent the intrusion of saline. Since the construction of the water gates, the water quality of the river has become degraded. This could also be due to the internal loading of pollutants, especially nutrients, from the sediments of the river because of the elongated detention time by the water gates. This study was thus conducted for the purpose of evaluating the current hydrologic-cycle system and providing measures for the rehabilitation of the hydrologic cycle. In this research, the daily outflow in Seonakdong River was simulated using the SWAT and SWMM models, and the water quality concentration including BOD, SS, TN, and TP were analyzed. The possibility of the application of SWAT-SWMM hybrid simulation was determined through the verification of both models. The error analysis shows that the results of both SWAT and SWAT-SWMM simulations make good agreements with those of field observations. For the single simulation results of SWAT, $R^{2}$ and NSE are 0.758, 0.511, respectively. For the hybrid simulation results of SWAT-SWMM, those are 0.880, 0.452, which means that the hybrid simulation can give more accurate results for the watershed where both the agricultural and urban areas exist.

• 한국수산과학회지
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• 제35권4호
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• pp.356-365
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• 2002

One of the most important factors that cause eutrophication is nutrient materials containing nitrogen and phosphorus which stem from excreation of terrestial sources and release from sediment. Therefore, to improve water quality, the reduction of these nutrients loads should be indispensible. At this study, the three-dimensional numerical hydrodynamic and ecosystem model, which was developed by Institute for Resources and Environment of Japan, were applied to analyze the processes affecting the eutrophication. The residual currents, which were obtained by integrating the simulated tidal currents over 1 tidal cycle, showed the presence of a typical counterclockwise eddies between Gyewha and Garyuk island. Density driven currents were generated westward at surface and eastward at the bottom in Saemankeum area where the fresh waters are flowing into, The ecosystem model was calibrated with the data surveyed in the field of the study area in annual average. The simulated results were fairly good coincided with the observed values within relative error of $30\%$. The simulations of DIN and DIP concentrations were performed using ecosystem model under the conditions of $40\~100\%$ pollution load reductions from pollution sources. In study area, concentration of DIN and DIP were reduced to $59\%$ and $28\%$ in case of the $80\%$ reduction of the input loads from fresh water respectively. But pollution loads from sediment had hardly affected DIN and DIP concentration, The $95\%$ input load abatement is necessary to meet the DIN and DIP concentration of second grade of ocean water quality criteria.

• 상하수도학회지
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• 제22권3호
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• pp.359-366
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• 2008

The series of experiments under the various conditions were carried out to evaluate the feasibility of dissolved air flotation (DAF) as an alternative of conventional gravity sedimentation (CGS) and to investigate the decrease of the loadings following to biological wastewater treatment processes in livestock wastewater system. On the basis of the experiment result between CGS and DAF processes, for the other water quality criteria as well as suspended solid the removal efficiency of DAF process was about 20~25 % better than CGS process on average. In addition, the particle removal efficiency of DAF process became higher in proportion as the increase of air to solid (A/S) ratio and the general wastewater treatment efficiency of DAF process was enough to meet the requirement of loading decrease to following biological process even at low A/S ratio range. Though DAF process is widely known as an solid separation unit, there was not the notable relationship between particle separation efficiency and several pollutant removal efficiencies like $COD_{Cr}$ and nutrients (T-N, T-P). Assume that the $COD_{Cr}$ was removed as the fraction of particle separation in this experiment, the removal efficiency of T-N and T-P were sensitive to removal efficiency of $COD_{Cr}$, especially.

• 한국농공학회지
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• 제31권3호
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• pp.93-102
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• 1989

With an objective to provide basic information for the management and the prediction of eutrophication in lentic water Systems, total amount of Kjeldahl nitrogen(T-N) and phosphorous(T-P) from irrigated water and drained water from flooded paddies were investigated during the rice growing period of 1988. A 29.3 ha paddies near Jungnam-myun, HwaSung-gun, Gyungi Province, Korea was instrumented for measuring runoff and sampling irrigated water and drained water from paddies. The following conclusions may be drawn from the result of this study. 1.During 115 days of investigation, T-N load for paddies was 362.6kg and T-P 63.44kg.These would be converted to 12.4kg T-N/ha and 2.17kg T-P/ha, respectively. 2.The T-N and T-P loadings in different periods showed a significant difference. The 25% of T-N loading was drained soon after fertilization period and 60% was drained during the rainy season from July 5 to July 24. 3.Annual loadings from paddies could be calculated to 30kg T-N/ha/year and 52kg T-P/ha/year considering non-measurement periods. 4.After the rainy season, the nutrient loads from drained water showed much less than those from irrigated water, and it may be suggested that the paddies would act as a stabilization pond. 5.The average concentrations of nutrients at 0.9km downstream from investigated paddies were 2.02(T-N) mg/l and 0.52(T-P) mg/I, which were 1.82(T-N) mg/l and 0.056(T-P)mg/l lower than those of drained water from paddies.

• 환경영향평가
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• 제32권5호
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• pp.291-304
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• 2023

녹조로 널리 알려진 남조류 과다증식은 심미적 불쾌감뿐만 아니라 독성물질을 생성하기 때문에 댐 수질 관리에 있어 큰 문제가 되고 있다. 녹조 발생을 억제하기 위하여 호소 유역으로부터 유입되는 비점오염물질 특히, 영양염류 저감이 필요하다. 본 연구에서는 친환경적 방법으로 알려진 인공습지의 장기간 운영 결과를 분석하여 비점오염물질 제어 수단으로서 인공습지의 적용 가능성 및 공정운영 관련 기초자료를 구축하기 위하여, 2014~2020년 동안 대청호 유역에 위치한 안내천 인공습지의 오염물질 처리효율을 분석하였다. 분석 결과, BOD 14.3%, COD 17.9%, SS 50.0%, T-N 19.0%, T-P 35.4%로 인공습지가 오염 물질 제거에 효과적임을 확인하였다. 계절별 처리효율은 오염물질별로 다른 경향을 보였는데, 주로 미생물의 반응에 의해 제거되는 BOD, COD, T-N은 겨울철에 비해 봄~가을에 높은 처리효율을 나타내었다. 그러나 수생식물에 의해 주로 제거되는 T-P는 처리효율에 있어 겨울에도 안정적인 처리효율을 나타내 호소 유입부하를 저감하는 데 효과적임을 확인하였다. 오염부하에 따른 제거율은 모든 오염물질이 유입수의 중간농도 및 고농도 구간에서 유출수 농도가 통계적으로 유의하게 감소한 것으로 나타났다. 이는 초기 강우와 같은 고부하 조건에서도 인공습지가 호소로 유입되는 비점오염물질을 안정적으로 제거해 호소의 부영양화를 억제하는 데 효과적으로 활용될 수 있음을 보여준다. 다만, 습지는 자연정화에 기반한 시설로 인위적인 공정 제어가 어렵기 때문에 향후 유역별 특성에 따라 다양한 운영사례 연구가 정립된다면 우리나라 호소의 녹조 문제 해결을 위해 유용한 방법이 될 것으로 판단된다.

• 한국환경농학회지
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• 제19권5호
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• pp.426-432
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• 2000

Field experiment was performed from August 1996 to December 1999 to examine the feasibility of constructed wetland system for sewage treatment in rural areas. A pilot system was installed in Konkuk University and the effluent of septic tank for school building was used as an influent to the wetland treatment basin. The system was composed of sand and reed, and operated continuously including winter time. Average removal rate of about 70% was observed for BOD, COD, and SS, about 50% for T-P, and about 25% for T-N. The reason for poor T-N removal might be due to high loading rate and short retention time. The system demonstrated satisfactory effluent concentration and stable performance in growing season. And it also worked adequately in wintertime even below $10^{\circ}C$ without freezing, and removal was still significant. The amount removed in BOD, COD, and SS was almost the same as in the growing season, and the amount removed in nutrients was about half of the one in growing season. Overall performance of the experimental system was compared with existing data base (NADB, 1994), and it was within the range of general system performance. As study period increased, removal rates for BOD, COD, SS, and T-P were consistently maintained and even enhanced, but removal rate for T-N decreased slightly. Wetland system was thought to be a feasible alternative for sewage treatment in rural area considering its low cost and low maintenance requirement. However, the effluent of the experimental wetland system often exceeded current effluent water quality standards, therefore, further treatment could be required if the effluent should be discharged to public waters. Wetland system of interest locates in rural area and is a part of rural ecosystem, therefore, ultimate disposal of reclaimed sewage for agricultural purpose or subsequent land treatment might be available and further research in this matter is recommended.

• 한국습지학회지
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• 제15권3호
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• pp.329-337
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• 2013

2008년 10월부터 2009년 9월까지 유입수계 하천의 수질특성을 파악하고 통계적 처리를 통하여 수질자료를 해석하였다. 순천만 유입수계 중에서 순천서천, 순천동천, 옥천은 환경부고시 하천수질 평가항목 모두에서 I등급으로 비교적 양호한 수질상태를 보였으나, 하천에서 유기물 오염의 지표인 BOD 항목에 대해서 해룡천과 순천만 유입지점에서는 각각 "약간 나쁨"과 "보통"의 결과를 나타내었다. 한편 총질소과 총인의 경우는 하수종말처리장 방류지점과 해룡천에서 다른 하천에 비해서 상대적으로 높은 결과를 나타내었다. 요인분석 결과 수질특성을 설명하는 1요인으로는 인간기원의 오염물질로서 기여율은 53.7%, 2요인으로는 지형적인 인자로서 기여율은 25.0%로 나타났다. 그리고 3요인은 자연환경의해서 기인된 요인들로서 기여율은 14.2%이며, 누적기여율은 92.8%로 평가되었다. 요인분석 결과 해룡천과 하수종말처리장 방류수로부터 상대적으로 많은 오염물질이 배출되어 순천만으로 유입되고 있어, 순천만의 수질 보존을 위해서는 순천하수종말처리장과 해룡천의 수질오염물질 배출의 보다 철저한 관리와 정화노력이 필요하다고 판단된다.

• 환경영향평가
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• 제26권1호
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• pp.68-77
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• 2017

낙동강 전 권역을 209개 유역으로 나누고 각 유역에서 배출되는 비점오염부하 기여율을 산정하기 위해 HSPF모델을 2012년 2013년을 기준으로 보정 및 검증을 실시하였다. 유량의 경우 보정한 결과 R2가 0.71~0.93, 검증은 0.71~0.79로 비교적 양호한 값으로 산정되었다. 수질의 경우는 % difference로 검 보정을 실시하였는데 보정의 경우 DO는 0.4~9.7 %, BOD는 0.5~30.2 % difference, TN은 낙본 C 및 황강 B를 제외 하고는 1.9~28.6 % difference로 나타났고 검증은 DO 0.2~13.7%, BOD는 1.3~23%, TN은 황강 B를 제외한 0.5~24.3%로 비교적 잘 모의 되었다. 그러나 TP는 농도가 다른 항목에 비해 미량이기 때문에 차이의 범위가 크게 나타났는데 보정의 경우 0.8~55.3 % difference이고 검증에서도 같은 결과를 얻었다. 209개 유역별 BOD 연간 누적부하량을 산정한 결과 RCH 123(경상남도 의령군), RCH 121(경상남도 진주시), RCH 92(대구광역시 달성군) 가 높은 것으로 나타났다. 그러나 영양염류에 대한 유역별 연간 누적부하량의 결과들은 BOD 연간 누적부하량 순위와 일치하지 않는 것으로 나타났다. 본류에 위치한 산림, 습지, 농지 등이 많은 유역들이 상대적으로 산림지역이나 습지가 많은 댐 상류지역의 유역들 보다 BOD 비점오염 부하량이 높은 것으로 나타났다. 토지형질을 비롯한 유역 특성들을 나타나는 다른 인자들이 비점오염 부하량과 밀접한 관계가 있는 것으로 나타났다.

• 생태와환경
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• 제45권4호
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• pp.368-377
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• 2012

본 연구는 영산강수계 수질 특성을 파악하기 위하여 2001~2010년까지 영산강 본류 10개 지점의 수질측정자료를 활용하여 총 18개 수질항목에 대하여 다변량분석법을 이용하여 수질항목간의 상관관계 및 요인분석, 군집분석을 수행하였다. 수질항목간 상관성은 BOD는 T-N, T-P와 높은 양의 상관성을, Chl-a는 COD와 유의한 양의 상관성을 보였다. 요인분석 결과 제1요인이 영양염류요인(32.021%), 제2요인이 유기물 및 조류증식에 따른 물질대사 요인(17.453%), 제3요인이 계절적 변동요인(14.775%), 제4요인이 미생물요인(10.951%)으로 추출되었다. 요인분석 결과로부터 추출된 제1요인과 제2요인에 대한 군집 분석 결과, 오염도가 낮은 그룹, 광주천 및 하수처리수 방류의 영향이 큰 오염도가 높은 그룹, 축산농가 및 농경지 등이 인근에 분포하는 그룹 등 3 그룹으로 분류되었다.