• 한국농공학회논문집
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• 제55권4호
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• pp.21-28
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• 2013

The objective of the study was to investigate the effect of rice straw mat, rice straw mat with PAM (Polyacrylamide) and gypsum addition on surface runoff and sediment discharge in field. Six experimental plots of $5{\times}22m$ in size and 3 % in slope prepared on gravelly sandy loam soil were treated with control, rice straw mat cover with gypsum and rice straw mat cover with gypsum and PAM. Radish in Spring and Chinese cabbage in autumn growing seasons were cultivated. Non point source (NPS) pollution discharge was monitored and compared among the treatments. Rainfall of the 10 monitored events ranged from 17.0 mm to 93.5 mm. Runoff coefficient of the events was 0.005~0.239 in control plot, 0~0.176 in rice straw plot with gypsum and 0~0.046 in rice straw mat plot with gypsum and PAM. When compared to the control plot, the runoff amount was reduced by 10.4~100 % (Ave. 60.8) in rice straw plot with gypsum and 80.7~100 % (Ave. 96.7 %) in rice straw mat plot with gypsum and PAM. The reduction of NPS pollution load was 54.6 % for BOD5, 71.5 % for SS, 41.6 % for TN and 61.4 % for T-P in rice straw with gypsum plot and 91.9 % for BOD5, 92.0 % for SS, 88.0 % for TN and 88.5 % for T-P in rice straw mat with gypsum and PAM plot. This research revealed that rice straw mat cover with soil amendments on the soil surface could not only increase the crop yield but also reduce the NPS pollution loads substantially.

• 한국도로학회논문집
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• 제9권4호
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• pp.185-192
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• 2007

최근의 환경정책은 신설되는 도로에 대하여 비점오염저감시설 설치의무화를 요구하고 있다. 또한 도로건설시 및 유지관리시에는 발생가능한 비점오염물질을 예측하고 이를 저감할 수 있는 방향으로 노선의 계획 및 설계와 더불어 다양한 비점저감방안을 수립할 것을 요구하고 있다. 비점오염원 및 비점오염물질을 관리하기 위해서는 우선 유역의 토지이용도를 분석하여 강우시 배출되는 오염물질의 종류와 양을 산정해야 한다. 특히 도로의 경우, 발생되는 비점오염물질의 원단위가 별도로 존재하지 않고 대지항목의 오염발생원단위를 사용하고 있기에 적용함에 있어서 많은 어려움을 겪고 있는 실정이다. 따라서 본 연구는 포장지역 중 고속도로 영업소를 대상으로 강우시 유출되는 강우유출수의 특성을 파악하여, 이러한 토지이용에서의 비점오염물질 유출특성과 부하량을 산정하고자 한다. 영업소 토지이용의 경우 많은 차량이 속도를 급격히 줄이는 토지이용지역으로 브레이크 패드, 각종 오일 및 엔진파트 등으로부터 많은 양의 오염물질이 축적되고, 포장률이 높아 강우시 다량의 오염물질이 유출되는 지역이다. 본 연구를 통해서 영업소 토지이용지역에서의 초기강우현상을 수리수문 및 농도곡선을 통해 확인할 수 있었다. 또한 EMC로부터 단위면적당 부하량과 강우지속시간당 부하량을 산정하였으며, 이러한 값은 영업소 유지관리시 인근수계에의 환경적인 영향을 해석하기 위한 기초자료로 활용될 수 있다. 강우지속시간당 유출되는 평균부하량은 TSS의 경우 $533.7mg/m^2-hr$, COD $396.2mg/m^2-hr$, TN $17.0mg/m^2-hr$, TP $4.8mg/m^2-hr$로 산정되었다.

• 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.

• 한국습지학회지
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• 제20권4호
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• pp.417-423
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• 2018

축산 지역 하류에 위치한 농업용 저수지의 강우시 유입, 유출수 분석을 통해 축산지역의 강우 유출 특성과 저류지에 의한 축산계 비점 오염물질의 저류형 시설에 의한 유출 저감 효율을 분석하였다. 급경사지에 위치한 한우 축산 지역의 비점 오염물질 유출은 주로 초기세척현상에 의해 발생됨을 알 수 있었으며 강우시의 유입수 농도는 비강우시에 비해 SS농도가 가장 높게 발생하고 있으며 T-P도 4배 이상 증가하는 양상을 보인다. 반면 총질소는 평균 30% 증가하는 것으로 나타나는데 질소항목으로 보면 질산성 질소는 거의 변화가 없는 반면에 암모니아성 질소가 2배 이상 증가하고 있다. 저류형 비점 제거시설 효율 분석 결과 비강우시 총인 제거효율이 53%로 가장 높고 부유물질은 37% 제거되고 있다. 유기물질은 10% 내외, 총질소는 5% 이내로 제거되며 부영양화로 녹조가 번성하는 하절기에는 오히려 유출수의 질소농도가 더 높아지는 경우도 빈번히 발생하고 있다. 강우시의 유입수 농도는 비강우시에 비해 SS농도가 가장 높게 발생하고 있으며 T-P도 4배 이상 증가하는 양상을 보인다. 강우시 부유물질의 제거효율은 60%로 나타나고 있으며 총인은 22% 제거되어 비강우시에 비해 제거효율은 감소하고 있다. 환경부의 비점제거시설 기준보다 9배 이상의 용량을 지니고 있지만 비점 전용 시설로 활용되지 못하는 탓에 장마철에 거의 만수 상태로 담수하여 비점제거 효율에 있어서는 충분한 효과를 보이지 못하고 있는 것으로 나타나 저수지의 용량 뿐 아니라 수문관리 등 유지관리도 비점 제거효율에 영향을 미치는 중요 인자로 분석되었다.

• 환경영향평가
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• 제20권5호
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• pp.651-661
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• 2011

The purpose of this study is to estimate the characteristics and pollutant loadings of non-point pollutants that flowed in the streams on precipitation for pollutant loading reduction of Hwa-sung lake inflow streams. Although it has been made an effort to improve the water quality of Hwa-sung basin through the strategies for the preservation of water quality, it is shown that the water quality is not greatly improved. Because it has been industrialized and urbanized near Hwa-sung basin so that it is difficult to reduce the water pollution due to the increase in pollutant loadings of point and non-point sources. In this study, it is investigated the outflow characteristics of non-point pollutants that discharged with storm runoff and estimated the effect of runoff on Hwa-sung basin. The final goal of this study is to utilize the basic information for proper management and strategies of non-point sources on Hwa-sung basin. At the result of inflow streams, Ja-an stream that has the greatest pollutant loadings on precipitation is strongly influenced on the water quantity of Hwa-sung basin. On the other hand, it is shown that Nam-yang stream is strongly influenced on the SS concentration of Hwasung basin among them. Also, all streams; Nam-yang, Ja-ahn, Ah-eun stream; has the degree of slope more than or near 1 in the correlation results so that they have strong pollutant loading impact and the concentration of SS is the highest among other pollutants. So, specific studies on initial rain phenomena are more necessary to manage the pollutants economically. Also, the proper control of SS concentration is required to manage the effluent pollutants effectively on precipitation. So, it is necessary to consider the strategies for non-point pollutants as well as point pollutants when the new management is imposed to reduce the pollutant load for improvement of Hwa-sung basin.

• 한국환경농학회지
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• 제33권2호
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• pp.144-147
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• 2014

BACKGROUND: It is essential to prioritize the exact and clear understanding of agricultural nonpoint source pollution (NPS) controls. The realistic policies and systems should also be developed based on this understanding. Therefore, this study aimed to present agricultural Best Management Practices (BMPs) applicable for the fields based on the Delphi survey result. METHODS AND RESULTS: This study deduced the evaluation items to assess each BMP for agricultural NPS control and conducted the surveying using the Delphi method based on agricultural BMP experts. In addition, its on-the-spot application were evaluated. Considering its importance, technical, social and economic proprieties showed that political support was ranked first and followed by cost investment, labor investment, reduction effect and resident participation. The survey findings by agricultural BMP experts showed the good performance of on-the-spot application can be achieved from fertilization by soil testing, residue and green manure application and contour plowing which are applicable within a field. Agricultural BMPs, highly applicable for the fields, were the countermeasures that farmers who are the principal bodies of agricultural NPS control could be participated directly. CONCLUSION: The active participation of farmers is essential for effective control of agricultural NPS. It is necessary to establish various incentive systems.

• 한국관개배수논문집
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• 제21권1호
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• pp.99-108
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• 2014

This study investigated the effects of NPS(non point source) pollution reduction of sediment traps through field experiments. Various sizes of 4 sediment traps were applied in a upland field located in Gunwi and assessed the infiltration and storage effects as well as NPS pollution reduction effects of this technique. The characteristics of deposited soil in the sediment traps were also analyzed including distribution of particle size, soil texture, and chemical properties. The results showed that slightly different composition of soil particle size from each sediment trap with high proportion of 0.15mm and 0.25mm ranges of soil particle diameters, while the loamy sand is the main types of deposited soils in the sediment traps. Decreased NPS pollution were observed from the water quality analysis of the samples taken from the sediment traps. Further research need to be proceeded continuously to improve this technique in order to utilize on upland fields for management of agricultural NPS pollutions.

• 상하수도학회지
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• 제20권5호
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• pp.763-770
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• 2006

The purpose of this study was to investigate the effects of mechanical(ball-mill) solubilization of excess sludge especially focused on the TSS(total suspended solid) reduction during the conventional aerobic digestion of sewage sludges including primary and/or excess sludge, HRT was examined at the 10 days and 20 days. According to the results of this study, TSS removal efficiency of solubilized excess sludge was almost two times higher than that of non-solubilized excess sludge. And as the proportion of the primary sludge increased, TSS removal efficiency became worse because primary sludge rarely contained microbial cells which could be easily solubilized physically. It was also proved that by the application of proper solubilization techniques to the excess sludge, HRT for the aerobic digestion could be lessened(above 50%) dramatically keeping the same or better digestion performance. The fact that between primary and excess sludges, only the excess sludge is quite effective in the sludge solubilization and in it's reduction says that excess sludge releasing sources are key-point in the sludge cake reduction field as a source control.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권1호
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• pp.77-83
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• 2012

In this paper, an optimal solution to the harmonic reduction problem in a cascaded multilevel inverter with non-equal DC sources using a genetic algorithm (GA) is presented. Switching angles are generated for different values of modulation index by the proposed algorithm, considering minimum voltage total harmonic distortion (THD) whereas selected harmonics are controlled within the allowable limits at all desired modulation indices including the point of discontinuity. Results are stored as a look-up table to be used to control the inverter for a certain operating point. The computed angles are used in a simulated circuit in Matlab\Simulink to validate the results.

• 한국농공학회논문집
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• 제54권1호
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• pp.55-62
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• 2012

This study is to assess the reduction of nonpoint source pollution by applying Best Management Practice (BMP) in Chungju-dam watershed (6,585.1 $km^2$) using Soil and Water Assessment Tool (SWAT). The model was calibrated using 3 years (1998-2000) daily streamflow at 3 locations and monthly water quality of sediment (SS), total nitrogen (T-N) and total phosphorus (T-P) data at 2 locations and validated for another 3 years (2001-2003) data. The 5 BMPs of streambank stabilization, porous gully plugs, recharge structures, terrace, and contour farming were applied to stream and area with the specific criteria of previous researches. Through the parameter sensitivity analysis, the farming practice P-factor and Manning's roughness of stream were sensitive. Overall, the NPS reduction effect was high for streambank stabilization, terrace, and contour farming. At the watershed outlet, the SS, T-P, and T-N were reduced by 64.4 %, 62.8 % and 17.6 % respectively.