• 아시안잔디학회지
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• 제23권1호
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• pp.35-44
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• 2009

본 연구는 해안가 매립지인 간척지에서 염분이 포함된 물을 관수하면서 한지형잔디와 난지형 잔디 총 8종의 생육을 평가해 보고자 수행되었다. 사용된 관개용수의 전기전도도(ECw)는 $0.28{\sim}3.3\;dS{\cdot}m^{-1}$)의 범위였다. 토양은 모세관수 차단층 처리구와 무처리구를 각각 비교하였다. 모세관수 차단층 처리구의 전기전도도는 $0.55{\sim}4.29\;dS{\cdot}m^{-1}$의 범위를 보였고, 모세관수 차단층을 설치하지 않은 시험구에서는 $1.8{\sim}9.4\;dS{\sim}m^{-1}$의 범위를 나타내었다. 파종 후 관행적인 관리 하에서 잔디의 피복률, 엽색, 품질, 밀도, 생육랑 등을 조사하였다. 간척지 염해지 조건에서 피복률이 90% 이상을 보이며 양호한 생육을 보인 초종은 '중지', 크리핑 벤트그래스, '세녹', '밀록' 등 4개 초종이었다. 켄터키블루그래스, 퍼레니얼 라이그래스, 켄터키+라이그리스 혼합 및 종자형 한극잔디 '제니스' 등 4 초종은 염해 피해를 받아 조성율이 70% 이하로 낮게 나타났다. 모세판수 차단층 설치지역에서는 크리핑 벤트그래스와 켄터키 블루그래스의 생육이 무설치구에 비해 우수하였으며, 난지형 잔디류는 모세관수 차단층 설치유무에 따른 피복률 차이는 관찰되지 않았으나, 뿌리길이는 모세관수 차단층 설치구가 길어지는 경향을 보였다. 본 연구자료는 간척지에 건설되고 있는 골프장에서 염류 모세관수 차단층 설치 유무에 따른 한지형 잔디와 난지형 잔디의 생육조건을 구명하는데 필요한 기초자료로 활용할 수 있을 것이다.

• 한국수자원학회논문집
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• 제43권2호
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• pp.153-165
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• 2010

Large-Scale Particle Image Velocimetry (LSPIV)는 Particle Image Velocimetry (PIV)를 실험실내의 비교적 규모가 큰 흐름이나 하천에서의 표면유속장의 측정 등 넓은 영역에 적용할 수 있도록 확장시킨 것이다. LSPIV는 PIV의 구성요소를 포함하여 추적자 투하, 조명, 촬영, 이미지 변환, 이미지 처리 및 후처리의 여섯 단계로 구성된다. 본 연구에서는 LSPIV의 모바일 버전인 MLSPIV를 이용하여 하천에서의 유속측정시 각 단계별로 발생가능한 오차성분을 정의하였고, 기존의 연구 결과를 바탕으로 오차의 영향이 정량적으로 밝혀진 것을 정리하였다. 각 단계별로 오차 발생요인을 조사한 결과 27개의 성분오차성분을 파악하였다. 이중에서 5개의 오차요소는 기존에 연구가 진행되었고, 7개의 오차요소는 본 논문에서 적용시의 MLSPIV에는 그 효과가 미치지 않는 것으로 파악하였다. 나머지 15개의 오차성분 중 4가지 오차성분- 샘플링시간, 이미지 해상도, 추적자의 성질, 바람-에 대해서 유속산정시 미치는 영향을 파악하기 위하여 개수로 실험장치를 이용한 실내시험을 실시하였다. 이미지 프로세싱에 이용한 이미지수로부터 나타나는 유속계산 오차를 조사한 결과 이미지의 개수가 50매 이상인 경우는 이로 인한 오차가 1 % 이하로 감소함을 파악하였다. 촬영된 이미지의 해상도가 유속계산시 미치는 영향을 조사하기 위해 세 가지 이미지 해상도로 변화시키면서 유속측정 오차를 분석한 결과 저해상도의 이미지를 이용한 경우 고해상도 이미지를 이용한 경우와 비교하여 3 % 가량의 차이를 나타내었다. 추적자의 성질과 바람의 영향에 대해서는 흐름의 평균유속이 큰 경우에는 바람이 추적자에 마치는 영향이 현격히 줄어듬을 보이고 있다. 즉, 유속이 증가함에 따라 바람의 영향은 감소하나, 바람의 영향을 최소화시키기 위해서는 가급적 비중이 큰 물질(0.5

• 한국물환경학회지
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• 제34권1호
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• pp.109-120
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• 2018

Sidestream in domestic wastewater treatment plants contains high concentration of ammonium, which increases nitrogen loading rate in the mainstream. The process for deammonification consisting of partial nitritation-anaerobic ammonium oxidation (ANAMMOX) and heterotrophic denitrification is an economical method of solving this problem. Currently, about 130 full-scale deammonification plants are fully operating around the world, but none is in Korea. In order to transfer the principal information about sidestream deammonification processes to researchers and operators, we summarized basic concepts, processes type, and key influence factors (e.g., concentration of nitrogen compounds, dissolved oxygen (DO), temperature, and pH). This review emphasis on the processes of single-stage sequencing batch reactor (SBR) deammonification, which are widely used as full-scale plants. Since simultaneous processes of partial nitritation, ANAMMOX and heterotrophic denitrification occur in a single reactor, the single-stage SBR deammonification requires appropriate control/monitoring strategies for several operating factors (DO and pH mostly) to achieve efficient and stable operation. In future, AB-process consisting of A-stage (energy harvesting from organics) and B-stage (ammonium removal without organics) will be applied to the wastewater treatment process. Thus, we suggest mainstream deammonification for B-stage connected with the sidestream deammonification as seeding source of ANAMMOX. We expect that many researchers will become more interested in the sidestream deammonification.

• 상하수도학회지
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• 제11권2호
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• pp.112-127
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• 1997

The purpose of this study is to get optimum operating factors of Upflow Anaerobic Sludge Blanket (UASB) reactor by introducing methods that make it to reduce inhibition possible in each process wastewater treatment. The used substrates, concentrated corn starch liquid (CSL) wastewater, modified starch, filtering and decoloring wastewater, ion refining wastewater, and mixed wastewater including modified starch and not including modified starch, are generated from molasses process. The seeding sludge is the digested sludge that had been applied to molasses wastewater. Batch test to reduce the inhibition factors that might be existed in each wastewater was examined. Based on the this test, the optimum operating factors according to alkalinity and pH variation was studied through the continuous test using three 5.5 L UASB reactor. The first reactor added $NaHCO_3$ to control alkalinity. The hydraulic retention time (HRT) reduced to 8 hours and the organic loading rate increased gradually. The second reactor changed the pH of influent from 7.0 to 6.0 using NaOH. The third reactor was operated without changes to compare the above two reactors. As the result, the inhibition in concentrated CSL wastewater was removed by adding iron (II). When trace metals were added to mixed wastewater not including modified starch, the digestability by gas production rate increased to more fifty percentage than mixed wastewater that was not adding the trace metals. The reason that the inhibition did not decreased in spite of adding trace metals and nutrients was influenced by high concentration generated during the acid fermentation. The UASB reactors using the mixed wastewater with the most effective performance were operated as 500 mg/L as $CaCO_3$ alkalinity and 6.0 pH at steady state, and at this time, the gas production rates were 283 and 311mL gas/g $COD_{added}$. The COD removal rates were 84.7 and 86.3%, respectively.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.182-182
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• 2017

The objective of this research was to determine controlling effects on rice blast (Pyricularia oryzae) in rice plants by using plant extracts from different extraction methods (water, boiling water, fermentation, and ethanol) from 38 agricultural materials of traditional agriculture. Rice blast was completely suppressed by 3% ethanol extracts in Rheum palmatum roots, and suppressed 97% and 77% by 10% ethanol extracts in onion bulb and pine tree leaves, respectively in a laboratory test. However, other agricultural materials showed low effect on suppression of rice blast. Additionally, in a seedling test, rice injury of two cultivars (Ilmibyeo and Hopyoungbyeo) against rice blast was reduced 40-71%, 29-63%, and 23-63% by 5 and 10% ethanol extracts in Rheum palmatum roots, onion bulb, and pine tree leaves, respectively, compared with non-treated controls. Rice injury of two cultivars (Ilmibyeo and Hopyoungbyeo) against rice blast was reduced by 21-55%, 23-46%, and 5-39% in response to Rheum palmatum roots, onion bulb, and pine tree leaf applications at 100, 200 and $400g/m^2$ at 0 day after seeding, respectively, compared with non-treated controls. Rice plants did not show any leaf injuries and growth reduction after treatments of the Rheum palmatum roots, onion bulb, and pine tree leaf extracts or soil application. Thus, the above materials may be used for controlling rice blast in organically produced rice fields.

• 상하수도학회지
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• 제14권1호
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• pp.37-44
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• 2000

Laboratory experiments were conducted to investigate the performances of anaerobic filters packed with ceramic tube and pall-ring media treating a dairy waste. The media packing volume was 65% of effective volume of anaerobic filter. Organics removals of anaerobic filters were maintained above 80% even at an organics loading rate of $10kgCOD/m^3/d$, and this was comparable to aerobic treatment of organic wastes. Organics removals of the ceramic tube anaerobic filters were always lower than those of the pall-ring anaerobic filters due to intrinsic physical property of ceramic tube, especially lower void space which caused to clogging and entrapment of biogas, substrate transfer limitation, and irregular evolution of biogas leading to loss of solids and biomass. This was clearly observed in higher concentration of TSS in the effluent from the ceramic tube anaerobic filter despite of higher retention capacity of TSS compared with pall-ring media. Vertical distribution of organics and solids in the filters showed above 90% of organics and solids in influent were removed below 20% of reactor height, and 50% of remaining organics and solids were removed though media packing zone. Effluent quality from the anaerobic filter was heavily depended on media itself as well as suspended biomass formed below media. It is therefore concluded that the type of media played an important role in biomass accumulation arid gas-liquid-solid separation efficiency. Type of media did not affect the start-up behaviors of the anaerobic filter, and supernatant from anaerobic digested sludge showed a good performance as a seeding materials.

• 한국물환경학회지
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• 제20권6호
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• pp.583-588
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• 2004

This research examined the treatment efficiency and methane production rate in treating slurry-type swine waste using UASB (upflow anaerobic sludge blanket) reactor. The UASB reactor was operated at an organics volumetric loading rate (VLR) of $2.6-15.7kgCOD/m^3/day$. A stepwise increase of the VLR resulted in a temporary deterioration in the COD removal rate in UASB reactor but recovered quickly. The COD removal rate were 65-70% for VLR up to $5 kgCOD/m^3/day$. When organics VLR was $10kgCOD/m^3/day$, the COD removal rate decreased sharply and there was loss of 17.537g of the seeding biomass due to sludge washout. This result indicated that the UASB system cannot be adapted to more than $10kgCOD/m^3/day$ of VLR. As the organic load increased from 2.6 to $15.7kgCOD/m^3/d$, the biogas production rate varied from 3.2 to 10.8 L/d and the methane conversion rate of the organic matter varied from 0.30 to $0.23m^3CH_4/kg\;COD_{removed}$. The methane content showed the range of 70.1-81.5% during the experimental period. The volatile solids (VS) removal efficiency was similar at the low VLR (< $5 kgCOD/m^3/day$), but it decreased sharply at the high VLR (> $5 kgCOD/m^3/day$). The VS reduction rate was, moreover, large those of COD. The result shows that hydraulic retention time above 2 days is essential in case of treating wastewater containing 1% of solids.

• 한국물환경학회지
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• 제28권6호
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• pp.917-922
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• 2012

In order to improve applicability of a microbial fuel cell the laboratory-scaled study has been performed by adopting an air-cathode MFC system with high concentrated anaerobic slugies in this study. The concentrations of microbes are grouped into three types, Type A (TS 1.7%), Type B (TS 1.1%) and Type C (TS 0.51%). The open circuit voltage $(V_{oc})$ characteristics showed that the medium microbes concentration of 1.10% (Type B) kept a constant voltage of 1.0 V for 150 hours, which showed the longest time among three types (Type A and Type C). The discharge charge curves for a closed circuit with $500 \Omega$ also showed that Type B generated a stable discharge voltage of 0.8 V for a longer time as in the open circuit voltage case. This could be explained by the relatively large amount of the attached microbes. Under the $V_{oc}$condition the COD removal efficiency of Type B was found to be low for a long time, but those of Type A and C were found to be high for a short period of time. Therefore, the suspended microbes could decrease the coulombic efficiency. It was concluded that the high $V_{oc}$ was caused by low COD and the $V_{oc}$ became low after the COD removal. The COD reduction resulted in an unstable and low working voltage. From the polarization characteristics Type A was found to show the highest power density of $193\;mW/m^2$ with a fill factor of 0.127 due to the relatively high remaining COD even after the MFC reaction.

• 한국양식학회지
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• 제12권1호
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• pp.25-30
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• 1999

피라미의 종묘를 생산하기 위하여인공부화, 먹이, 성장을 조사하였다. 난황이 갓 흡수된 개체는 전장이 7.6~8.2mm(평균 7.97mm) 이었으며, 부화 후 3일만에 부상하였다. 부상 후 소형 물벼룩, 윤충류, 알테미아를 섭취하였으며, 초기용 인공 분말사료도 섭취하였다. $20~32^{\circ}C$의 온도조건에서 부화시험을 한 결과 부화율은 $26^{\circ}C$에서 가장 높았으며, 47시간이 소요되었다. 부화기의 형태 중에서는 부화병에서 부화율이 89%로 가장 높았으며, 그물상자 및 Californian 부화기에서도 부화율 80% 이상으로 높았다. 부화 후 50일간 사육 한 결과 30.0mm(25.6~32.0mm)로 성장하였다. 온도가 높을수록 자어의 성장이 빨랐는데, 특히 $26^{\circ}C$ 이상에서 성장이 양호하였다. 그러나, 생존율은 $32^{\circ}C$에서 가장 낮았다. 부화직후부터 배합사료만으로서 사육이 가능하였으며 알테미아나 잉어용 사료에 비해서 넙치 및 조피볼락용 사료에서 성장이 양호하였다.

• 한국작물학회지
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• 제44권3호
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• pp.230-235
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• 1999

To study the effects of an urease inhibitor, N-(n-butyl)-thiophosphoric triamide (NBPT), and a nitrification inhibitor, dicyandiamide (DCD), on nitrogen losses and nitrogen use efficiency, urea fertilizer with or without inhibitors and slowrelease fertilizer (synthetic thermoplastic resins coated urea) were applied to direct-seeded flooded rice fields in 1998. In the urea and the urea+DCD treatments, NH$_4$$^{+}$ -N concentrations reached 50 mg N L$^{-1}$ after application. Urea+NBPT and urea+ NBPT+DCD treatments maintained NH$_4$$^{+}$ -N concentrations below 10 mg N L$^{-1}$ in the floodwater, while the slow-release fertilizer application maintained the lowest concentration of NH$_4$$^{+}$ -N in floodwater. The ammonia losses of urea+NBPT and urea+NBPT+DCD treatments were lower than those of urea and urea+DCD treatments during the 30 days after fertilizer application. It was found that N loss due to ammonia volatilization was minimized in the treatments of NBPT with urea and the slow-release fertilizer. The volatile loss of urea+DCD treatment was not significantly different from that of urea surface application. It was found that NBPT delayed urea hydrolysis and then decreased losses due to ammonia volatilization. DCD, a nitrification inhibitor, had no significant effect on ammonia loss under flooded conditions. The slow-release fertilizer application reduced ammonia volatilization loss most effectively. As N0$_3$$^{[-10]}$ -N concentrations in the soil water indicated that leaching losses of N were negligible, DCD was not effective in inhibiting nitrification in the flooded soil. The amount of N in plants was especially low in the slow-release fertilizer treatment during the early growth stage for 15 days after fertilization. The amount of N in the rice plants, however, was higher in the slow-release fertilizer treatment than in other treatments at harvest. Grain yields in the treatments of slow-release fertilizer, urea+NBPT+ DCD and urea+NBPT were significantly higher than those in the treatments of urea and urea+DCD. NBPT treatment with urea and the slow-release fertilizer application were effective in both reducing nitrogen losses and increasing grain yield by improving N use efficiency in direct-seeded flooded rice field.field.