• 한국환경농학회지
• /
• 제24권3호
• /
• pp.289-294
• /
• 2005

The toxic effects of 12 commercially available insecticides on the earthworm, Eisenia fetida (Savigny), were evaluated using artificial soil, surface sprayed soil, immersion, and contact filter tests. The risk to earthworm was assessed by the TER (toxic exposure ratio) value, which was calculated by the formula, TER=NOEC/PEC (predicted environmental concentration). TER was 3 for methomyl SL, 20 for carbaryl WP, 20 for phosphamidon SL, 30 for imidacloprid WP, and 60 for dichlorvos EC the in artificial soil test. At recommended, the earthworm mortality to methomyl SL reached 50% in the surface sprayed soil test, 72% in the immersion test, 30% in the contact filter paper test, whereas that to imidacloprid WP reached 56, 32, and 100 respectively. As a result of the four methods, methomyl SL and imidacloprid WP would be toxic insecticides to earthworm.

• 한국물환경학회지
• /
• 제31권4호
• /
• pp.407-417
• /
• 2015

Soil loss is one of the significant disasters which have threatened human community and ecosystem. Particularly, Korea has high vulnerability of soil loss because rainfall is concentrated during summer and mountainous regions take more than 70% of total land resources. Accordingly, the sediment control management plan are required to prevent the loss of soil resources and to improve water quality in the receiving waterbodies. In this regard, the objectives of this study are 1) to quantify the effect of the Vegetative Filter Strip (VFS) on sediment runoff reduction and 2) to analyze the relationship of rainfall intensity and sediment runoff. For this, SATEEC and VFSMOD were used to estimate sediment runoff according to rainfall intensity and to quantify the effect of VFS on sediment runoff reduction, respectively. In this study, the VFS has higher impact on sediment reduction for lower maximum rainfall intensity, which means that the maximum rainfall intensity is one of significant factors to control sediment runoff. Also, the sediment with VFS considered was highly correlated with maximum rainfall intensity. For these results, this study will contribute to extend the applicability of VFS in establishing eco-friendly sediment control plans.

• 한국토양비료학회지
• /
• 제39권5호
• /
• pp.280-284
• /
• 2006

농경지에 과거에 사용했거나 사용중인 살균제 14종에 대하여 농경지에 뿌려지는 추천사용량을 기준으로 토양표토처리법, 침지법, 여지접촉법으로 실험을 수행하였다. 그 결과 추천사용량에서 14종의 농약이 무처리와 통계적으로 유의성이 없는 것으로 나타나, 이런 농약들은 줄지렁이 치사에 영향을 주지 않는 것으로 판단되었다. 그러나 benomyl, Thiophanate-methyl, carbendazim 농약은 지렁이에게 독성이 높은 것으로 보고되어 있어 추가적인 검토가 필요하다고 생각된다.

• 환경영향평가
• /
• 제26권5호
• /
• pp.344-353
• /
• 2017

캄보디아는 동남아 지역에서 매우 유명한 관광국가임과 동시에 심각한 물 문제를 가지고 있는 대표적 국가로 인식되고 있다. 공공위생의 관점에서 캄보디아의 물 문제는 대략 두가지 카테고리로 구분된다. 상당히 많은 수의 보고서들이 지표수와 지하수 문제에 대해 분원성 미생물과 비소 오염이 각각 가장 대표적인 문제인 것으로 보고하고 있다. 최근에 가정용 정수기 시스템으로서 생물-모래여과기, MF, RO 등 다양한 소재를 이용한 시스템들이 농촌지역에 보급/채택되었다. 그러나 BSF와 조합형 막여과 공정들은 신뢰하기 어려운 효율, 높은 멤브레인 교체비용과 유지관리의 문제점들로 인해 당초 기대에 미치지 못하는 기술로 인식되기 시작하였다. 금번 연구는 가정용 정수기로서 활용이 가능한 소형 세라믹 필터를 개발하기 위해 캄보디아 북서부의 점토와 황토를 이용하여 두 종류의 중력식 세라믹 필터를 만들었고, 이들에 대한 현지 적용성 여부를 평가하였다.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제19권3호
• /
• pp.15-24
• /
• 2014

Soil pollution has been recognized as a serious problem because it causes groundwater pollution through medium contacts. Although concentration of individual chemical could be more easily measured by physico-chemical analysis, it is not easy to consider the bioavailability of edaphic receptors living in soil or groundwater. To measure the toxicity of soil, the soil extracts (soil elutriates or soil suspensions in the other words) are often used due to the difficulties of extracting soil pore water. In this study, we reviewed 15 toxicity test methods found in literature to analyze the detail of each extraction method and to recommend the most frequently used extraction methods. The identified most commonly used extraction methods are as following: The 1 : 4 soil:water ratio, 24 hours shaking time, room temperature, dark, and separation of supernatant using a $0.45{\mu}m$ pore size filter.

• 한국물환경학회지
• /
• 제32권6호
• /
• pp.537-545
• /
• 2016

In order to cope with the new and strict government regulations for turbid water discharge from construction sites, this study tested whether synthetic fiber filters can replace conventional best management practices. The filter efficiency was about 10 to 60% with a varying filter depth of 5 to 15cm, presuming extreme storm flow conditions to be in the range of 800 to 1500m/day of filtration rates. Fiber filter acts exactly like a granular filter, i.e. the separation efficiency is directly and inversely proportional to filter depth and rate, respectively. Based on the operational data, we suggested the Log-Log design relationship, which can be used to determine the filter depth and area. Compared to the widely used gravel filter which treats the turbid water at the construction site, about 20% higher efficiency was obtained under similar operating conditions. Cleaning the filter through a simple hand-washing method at the time of break-through, achieved about 90% soil recovery.

• 한국지반공학회논문집
• /
• 제18권4호
• /
• pp.249-256
• /
• 2002

Slurry trench의 안정성은 안정액의 유압이 filter cake 막을 통하여 trench 벽에 전달됨으로서 확보될 수가 있다. 지반조건의 영향에 따른 slurry trench 공법에서 주변 공극수압의 변화를 수치해석(FEM)으로 추적하였다. 이러한 주변 공극수압의 변화 요인으로는 안정액의 밀도, filter cake의 상태, 토질조건, 시간, trench 심도, 주변지하수위로 조사되었으며, 가장 큰 영향력을 보인 요인으로는 토질조건과 filter cake 상태로 나타났다.

• 한국지반공학회논문집
• /
• 제18권4호
• /
• pp.239-248
• /
• 2002

안정액(bentonite slurry)을 이용한 지하연속벽의 건설은 굴착된 trench 내에서 안정액이 침투케익과 표면케익을 포함한 불투수막을 형성함으로서 trench 의 안정성을 유지할 수가 있다. 그러므로 구조용 지하연속벽 건설이나 폐기물 매립장의 차수용 연속벽 건설시 지반조건 및 주변여건의 변화에 의하여 여러 가지 문제가 발생 될 수 있다. 본 논문은 안정액 유출과 불투수케익 형성과정을 대형실험으로 모델링하여 그 결과가 slurry trench 안정성에 미치는 영향을 평가하고, 현장조건에 적합한 설계절차를 제시하였다.

• 한국해양공학회지
• /
• 제19권2호
• /
• pp.82-89
• /
• 2005

This study deals with the development of the extended Kalman filter(EKF) algorithm for the localization of underwater mining vehicles. Both simulation and experimental studies in a test bed are carried out. For the experiments, a scale dawn tracked vehicle is run in a soil bin containing cohesive soil of bentonite-water mixture. To develop the EKF algorithm, we use a kinematic model including the inner/outer track slips and the slip angle for the vehicle. The measurements include the inner and outer wheel speeds from encoders, the heading angle from a compass sensor and a fiber optic rate gyro, and x and y coordinate position values from a vision system. The vision sensor replaces the LBL(Long Base Line) sonar system used in the real underwater positioning situations. Artificial noise signals mimicking the real LBL noise signal are added to the vision sensor information. To know the mean slip values of the tracks in both straight and cornering maneuver, several trial running experiments are executed before applying the EKF algorithm. Experimental results show the effectiveness of the EKF algorithm in rejecting the sensor measurements noise. Also, the simulation and experimental results show close correlations.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.498-507
• /
• 2008

The mixture of bentonite powder and water is generally used to maintain the stability of excavation surface during the construction of vertical cutoff walls. The filter cake on the sidewall surface is the result of filtration of slurry into the adjacent soil formation. The filter cake is believed to have a very low hydraulic conductivity compared to that of the cutoff wall. This paper evaluates hydraulic conductivities of bentonite filter cakes set up with three types of bentonites under various pressure levels. A modified fluid loss test was employed in this experiment. Theory of filtration process was reviewed to explain the procedure in the present experiment. Hydraulic conductivity of the filter cakes with consideration of the filter medium resistance was evaluated. The results of the experiment with two calculation methods and discussion are presented to show the efficiency of the modified fluid loss test.