• Animal cells and systems
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• 제7권4호
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• pp.295-301
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• 2003

Effects of the settlement density of germlings and canopy on settled germlings of Fucus serratus were investigated on the rocky shore of the Isle of Man. The survival of transplanted germlings was mainly determined by parent canopy rather than by initial settlement density of germlings. However, germling growth was greater at low density than at high density and enhanced by canopy removal. Recruitment by natural propagules was stimulated at high settlement density and maximal recruits occurred on caged slides under the canopy. On the experimental slides, tiny snails and sedimentation were ,found. The number of snails was positively related with the settlement density of germ lings indicating that they fed the germlings. Sedimentation and snail number were greater with canopy removal treatments than in canopy intact ones. These indicate that ,canopy sweeping gives benefits to germlings by removing sediment from substrata and protecting them from herbivores. In conclusion, the survival of settled F. serratus germlings is mainly determined by canopy sweeping and their growth is retarded in the presence of a canopy and at high settlement density.

• 환경위생공학
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• 제7권1호
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• pp.45-56
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• 1992

The Anaerbic Anoxic/oxic process is one of the biological treatment methods to remove nitrogen and phosphorus effectively which are nutritional elements for eutrophication. Supernatant of primary sediment of Anaerobic digester is used as a carbon source instead of methanol methanol supply in usual A$_{2}$/O process. The efficiency of the following treatment processes are as follow : 1) Changing recycle ratio in the usual A$_{2}$/O process without the stage of Anaerobic digester. 2) Changing recycle ratio in the usual A$_{2}$/O process with the supernatant supply of the Anaerobic digester. In the result of comparison, changing recycle ratio is almost no effect in the removal of phosphorus, however the effect of removal in nitrogenous substance are remarkable, and the effect of Anaerobic digester is not as effective as expected because the BOD removed in the digester partly, the rate of phosphorus to the BOD exceed pertinent range.

• 한국물환경학회지
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• 제33권2호
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• pp.123-129
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• 2017

The purpose of this study is to identify potential methodologies to reasonably estimate the effectiveness of road vacuum cleaning in terms of pollution loads reduction. In this context, this study proposes two empirical equations to estimate the amount of diffuse pollution loads removed by road vacuum cleaning. The proposed equations estimate the removed amount of pollution loads respectively taking into consideration of: a) the distance of road vacuum cleaning; and b) the amount of road-deposited sediment(RDS). All of the parameters in these equations were evaluated based on results of field monitoring and laboratory analyses, except for the RDS generation rate. The results of this study suggest that pollutant removal efficiency is 46.3% for $BOD_5$ and 56.4% for TP; discharge ratios for particulate and dissolved $BOD_5$ are 35.0% and 21.2%, respectively; discharge ratios for particulate and dissolved TP are 35.0% and 19.4%, respectively. Average concentrations of pollutants in RDS are $BOD_5$ 977.3 mg/kg and TP 317.6 mg/kg. Some results of a case study imply that both equations can be potentially useful if the adopted parameters are reasonably evaluated. In particular, the RDS generation rate should be evaluated based on monitoring data collected from various road conditions.

• 한국지리정보학회지
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• 제10권3호
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• pp.22-30
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• 2007

항공사진을 이용해 산지토사재해 구간의 DTM(Digital Terrain Model)을 제작할 경우 수목이 재해구간을 가리는 경우가 많아 연속적이고 정밀한 DTM을 얻기가 매우 어렵다. 본 연구에서는 이러한 어려움을 해결해 보고자 디지털항공사진을 이용하여 moving window 형태의 필터링방법을 제시하였으며 DTM을 추출하였다. 또한 산지토사재해 구간에서 적정한 필터링의 window 크기에 따른 수목영향제거의 효과를 알아보기 위해 상용 수치사진측량 S/W인 Socet set의 Adaptive 필터링한 DTM과 LiDAR(Light Detection And Ranging)에서 획득한 DTM을 비교하였다. 그 결과 LiDAR에서 획득한 DTM보다는 정확도가 낮았지만 Adaptive 필터링보다는 정확도가 약 6m 정도 높은 결과를 얻을 수 있었다.

• 대한환경공학회지
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• 제33권11호
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• pp.834-846
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• 2011

본 연구의 목적은 하천, 호수의 준설 시에 발생하는 준설토 사토장에 저류된 부유물질을 hydrocyclone을 이용하여 모래입자를 분리하고, 부유미세입자 및 오염물질을 처리하기 위해 키토산 응집제를 이용하여 고속 응집과 침전이 가능한 IDFIS 시스템을 개발함에 있다. 응집교반실험 결과 키토산 주입농도는 하천퇴적물질의 경우 40 mg/L, 터널굴착 퇴적물질의 경우 5 mg/L에서 잔류탁도는 5 NTU 이하를 나타내었다. 키토산응집제는 응집, 응결조건에 pH 영향이 거의 없으므로 처리장치 운전의 용이성에 기여할 것으로 판단된다. IDFIS장치를 이용하여 황토입자, 하천퇴적물질, 하천부유사 퇴적물질, 터널굴착 퇴적물을 대상으로 제거특성을 분석한 결과 전반적인 평균 처리효율은 탁도 98%, SS 99%, COD 85%, TP 95%를 나타내었다. 키토산응집제는 다양한 탁도 범위에서도 입자물질의 제거에 매우 효과적인 것으로 분석되었다. IDFIS장치는 키토산응집제로 빠르게 형성된 플럭을 높은 수면적부하율로 처리 가능하여 집적화된 처리장치로서 활용도가 높을 것으로 판단된다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권6호
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• pp.85-94
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• 2015

RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) is the most important explosive contaminant, both in concentration and in frequency, at military shooting ranges in which green technologies such as phytoremediation or constructed wetlands are the best option for mitigation of explosive compounds discharge to the environment. A study was conducted with two identical lab-scale plug flow constructed wetlands planted with Amur silver grass to treat water artificially contaminated with 40 mg/L of toxic explosive compound, RDX. The reactor was inoculated with or without RDX degrading mixed culture to evaluate plant-microorganism interactions in RDX removal, transformation products distribution, and kinetic constants. RDX and its metabolites in water, plant, and sediment were analyzed by HPLC to determine mass balance and kinetic constants. After 30 days of operation, the reactor reached steady-state at which more than 99% of RDX was removed with or without the mixed culture inoculation. The major transformation product was TNX (Trinitroso-RDX) that comprised approximately 50% in the mass balance of both reactors. It was also the major compound in the plant root and shoot system. Acute toxicity analysis of the water samples showed more than 30% of toxicity reduction in the effluent than that of influent containing 40 mg/L of RDX. In the Amur silver grass mesocosm seeded with the mixed culture, the specific RDX removal rate, that is 1st order removal rate normalized to plant fresh weight, was estimated to be 0.84 kg⁻¹ day⁻¹ which is 16.7% higher than that in the planted only mesocosm. Therefore, the results of this study proved that Amur silver grass is an effective plant for RDX removal in constructed wetlands and the efficiency can be increased even more when applied with RDX degrading microbial consortia.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권1호
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• pp.57-66
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• 2013

Although the quantity of dredged soils has increased owing to recent new harbor construction, sea course management, polluted sediment dredging, and four-river project, the reuse or recycling of those dredged soils has not done properly in Korea. To develop measures to utilize them in various ways for reuse or recycling, the biophysicochemical properties of dredged soils and sediment were assessed in this study. Samples were classified according to their sources-river and sea-by location, and as dredged soil and sediment depending on storage time. The results showed that dredged materials from the sea have high clay content and can be used for making bricks, tiles, and lightweight backfill materials, while dredged materials from the river have high sand content and can be used in sand aggregates. Separation procedures, depending on the intended application, should be carried out because all dredged materials are poorly sorted. All dredged soils and sediments have high salinity, and hence, salts should be removed before use for cultivation. Since dredged materials from the sea have adequate concentrations of nutrients, except phosphate, they can be used for creating and restoring coastal habitats without carrying out any additional removal processes. The high overall microbial activities in dredged materials from the river suggested that active degradation of organic matter, circulation of nutrients, and provision of nutrients may occur if these dredged materials are used for cultivation purpose.

• Journal of Ecology and Environment
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• 제38권1호
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• pp.57-65
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• 2015

A natural mixed stand of Phragmites australis and Phacelurus latifolius was studied to clarify the distribution properties in a microsite in a tidal flat of Suncheon Bay. The height, density, and biomass of the shoots, as well as the biomass of the root system, were monitored for both species along with the altitude on a mound from June 2010 to October 2013. Firstly, the mean height and dry weight of both species were similar during the growth season. However, individual variations of the sizes of plants in the same species were noticeable. Secondly, the density and dry weight per unit area of P. latifolius increased, but that of P. australis decreased with the altitude on the mound. Thirdly, the root system (rhizomes and roots) of P. latifolius was mostly located in the upper layer (up to 20 cm depth), while that of P. australis was in the lower layer (over 70 cm depth) of the sediment. The roots of P. australis penetrated to the lower parts of the water table, while the roots of P. latifolius did not make contact with free water of the sediment. Fourthly, the removal of the shoot in the early growth season led to a visible reduction of biomass in the late growth season. The reduction rate was larger in P. latifolius than in P. australis. Lastly, in the area where the mound was removed, the density of P. australis increased in the first two years (2010-2011) and was highly sustained inthe last two years (2012-2013). However, the density of P. latifolius was low, and this plant was distributed at the edge of the mound only.

• 한국지하수토양환경학회지:지하수토양환경
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• 제24권4호
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• pp.1-10
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• 2019

Recently, groundwater contamination by mixed occurrence of arsenic (As) and nitrate ($NO_3{^-}$) has been a serious environmental issue all around world. In this study, we investigated the microbial As(III) oxidation characteristic under denitrification process to examine the feasibility of the microbial consortia in wetland sediment to simultaneously treat these two contaminants. The detail objectives of this study were to investigate the effects of $NO_3{^-}$ on the oxidation of As(III) in anaerobic environments and observe the microbial community change during the As oxidation under denitrification process. Results showed that the As(III) was completely and simultaneously oxidized to As(V) under denitrification process, however, it occurred to a much less extent in the absence of sediment or $NO_3{^-}$. In addition, the significant increase of As(III) oxidation rate in the presence of $NO_3{^-}$ suggested the potential of As oxidation under denitrification by indigenous microorganisms in wetland sediment. Genera Pseudogulbenkiania, and Flavisolibacter were identified as predominant microbial species driving the redox process. Conclusively, this study can provide useful information on As(III) oxidation under denitrifying environment and contribute to develop an effective technology for simultaneous removal of As(III) and $NO_3{^-}$ in groundwater.

• 대한환경공학회지
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• 제36권8호
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• pp.554-560
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• 2014

해양오염퇴적물 정화를 위한 몬모릴로나이트의 피복소재 적용성 평가를 위하여 $PO{_4}{^{3-}}$ 흡착특성을 알아보고자 동적흡착, 평형흡착, pH, 흡착제 주입량, 이온경쟁, 타 흡착제 복합사용 그리고 해수에서의 흡착특성을 살펴보았다. 동적흡착실험 결과 50 mg/L의 농도에서는 1시간대에 흡착평형을 나타내었고, 300 mg/L의 농도에서는 3시간대 흡착평형을 나타내었다. Freundlich 모델과 Langmuir 모델을 적용한 결과 다층흡착을 가정한 Freundlich 모델이 $PO{_4}{^{3-}}$의 평형 흡착에 더 잘 부합하였고, $PO{_4}{^{3-}}$의 흡착은 pH가 낮을 때 높은 흡착경향을 나타내었다. 이는 높은 pH에서는 OH-가 경쟁관계를 형성함으로 판단된다. 이온 경쟁관계 실험 결과 질산, 황산, 중탄산 모두 몬모릴로나이트의 $PO{_4}{^{3-}}$ 흡착에 영향이 미비한 것으로 나타났다. 몬모릴로나이트는 적니와 제강슬래그를 혼합하여 사용하는 것보다 단일 사용하였을 때 $PO{_4}{^{3-}}$ 제거에 더 효과적이었다. 해수에서의 $PO{_4}{^{3-}}$ 흡착특성을 살펴본 결과 담수에서의 흡착량 보다 높은 결과를 나타내었고 이는 해수 내 존재하는 칼슘이온 등의 결과로 판단된다. $PO{_4}{^{3-}}$ 용출 수조실험결과 몬모릴로나이트 피복 수조는 실험 14일까지 $PO{_4}{^{3-}}$이 측정되지 않았다. 몬모릴로나이트는 수용액중 $PO{_4}{^{3-}}$ 흡착 제거에 효과적인 피복소재로 판단된다.