• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.692-700
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• 1996

The objective of this study is to develop a systematic purification plant using the metabolism of aerobic microorganisms. This system is subsequently aerated and continuously removes suspended solids and settling sludges caused by aerating pressure at the bottom of a lower pipe (i.e., Continuous Removal of Suspended solids and Settling sludges, CRSS). The CRSS plants are brought out by introducing fine air bubbles into the liquid phase of a lower pipe in the bio-reactor. These plant uses aeration pipe, with multiple inlets to sweep the floor of bio-reactor tank, instead of the conventional scraper mechanisms. The principal advantage of this system is that it can continuously remove very small or light particles that settles completely within a short time. Once the particles have been floated to the surface, they can be moved into the pipe and collected in the settling tank by sequently aerated pressure. The experimental results shows that about 99.0% of the biochemical oxygen demand(BOD), 99.3% of the suspended solid(SS), 92.3% of the total nitrogen(T-N), 99.0% of the turbidity(TU), 100% of the total coliform(TC)and ammonia was respectively removed during aerobic digestion for 9 days. These result indicates that the CRS S plants are very effective for reduction and deodorization of swine wastewater contaminants, and the efflux from CRS S can either be discharged in the river or used as nutrient solution of formulation for plant growth factories. The developed CRSS plant proved to be flexible and it can simply be adapted to any type of biological waste treatment problem.roblem.

• 대한지하수환경학회지
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• 제5권4호
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• pp.215-222
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• 1998

지하수 세균 군집에 미치는 환경요인의 영향을 분석하기 위하여, 서울 시내에서 음용수로 사용하는 2개 정점과 음용수외 생활용수로 사용하고 있는 8개 정점을 대상으로 조사하였다. 물리.화학적 환경요인과 중금속의 농도, 및 세균 군집의 분포 등 40개 변수를 분석한 결과, 음용수로 사용하는 정점을 제외한 나머지 정점에서 질산성 질소와 암모니아가 용수목적별 수질기준의 기준치 이상으로 측정되었다. 총세균은 5.1~41.4$\times$$10^{5}$cells/ml 범주로, 종속영양세균과 기능성 세균군집은 0.01~29.6$\times$$10^4$cfu/ml의 범주로 조사되었다. 세포외 효소의 활성도는 0.005~11.3$\mu$M/l/hr 의 범주로 나타났고, lipase, phophatase, $\beta$-glucosidase, cellulase, chitinase, amylase 순으로 활성도가 나타났다. 정점별로 조사된 세균 군집에 미치는 환경요인의 상호관계는 대응분석(correspondence analysis)과 다차원 척도법 분석(multidimensional scaling; MDS)으로 하였으며, 그 결과 4개의 집단으로 구분되었으며, 세균 군집에 미치는 주요한 환경요인은 정점별 잠재오염원과 일치하는 양상을 보였다.다.

• 한국물환경학회지
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• 제29권1호
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• pp.1-6
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• 2013

This study was focused on improving nitrification efficiencies of M-dephanox (Modified-Dephanox) process. Rotating biological contactor (RBC) was used instead of floating sponge type media in nitrification reactor. High ammonia removal efficiencies were observed in nitrification reactor, regardless of organic loading from contactor of M-dephanox process. Denitrification efficiencies were also increased to maintain low $NO_3-N$ concentration in effluent. This enhanced phosphate release in anaerobic contactor and resulted in high removal efficiencies of phophorus. Average removal efficiencies of $TCOD_{Cr}$ and $SCOD_{Cr}$ were 93.8% and 81.6%, respectively, while those of TKN and ${NH_4}^+-N$ were 80.9% and 74.4%, respectively. As for phosphorous treatment, the average removal efficiencies of TP and OP were 94.7% and 94.3%, respectively. Also, effect of operating temperature on nitrogen removal was examined. Average removal efficiency of TN was 65.8 % at $15^{\circ}C$ or below (at average temperature of $13.3^{\circ}C$), while that was 82.8% at $15^{\circ}C$ or above (at average temperature of $21.9^{\circ}C$).

• 상하수도학회지
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• 제18권6호
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• pp.731-741
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• 2004

The purpose of this study was to evaluate the potential of a gamma ray irradiation to decompose hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in an aqueous solution. The decomposition reaction of RDX by gamma ray irradiation was a first-order kinetic over the applied initial concentrations (10-40mg/L). The dose constant was strongly dependent on the initial concentration of the RDX. The removal of RDX was more efficient at pH below 3 and at pH above 11 than at neutral pH (pH 5-9). The required irradiation dose to remove 99% of the RDX (40mg/L) was 4, 8 and 1 kGy, at pH 2, 7 and 13, respectively. The dose constant was increased by two folds and over twelve folds at pH 2 and 13, respectively, when compared with that at pH 7. When an irradiation dose of 20 kGy was applied, the removal efficiencies of TOC were 80, 57 and 91% at pH 2, 7 and 13, respectively. Ammonia and nitrate were detected as the main nitrogen byproducts of RDX and formic acid was detected as an organic byproduct. The results showed that a gamma ray irradiation was an attractive method for the decomposition of RDX in an aqueous solution and it was found that a strong alkaline pH over 12 should be applied to the decomposition reaction of RDX.

• 공업화학
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• 제19권4호
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• pp.376-381
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• 2008

화력 발전소에서 발생되는 질소산화물(NOx)을 제거하기 위하여 환원제로써 $NH_3$를 이용한 선택적 촉매환원법(Selective Catalytic Reduction: SCR)에 사용되는 $V/TiO_2$ 촉매의 활성저하에 관하여 연구하였다. 장기간 배기가스에 노출된 촉매(Used-cat)의 활성과 비표면적이 상당히 감소되었다. 촉매의 특성분석은 XRD, FT-IR, FE-SEM, IC/ICP 등을 이용하여 수행하였다. 분석결과 배기가스에 노출되지 않은 사용 전 촉매(Fresh-cat)와 사용 후 촉매(Used-cat) 두 촉매 모두 $TiO_2$의 결정구조는 변하지 않았다. 그러나, FT-IR, FE-SEM, IC/ICP에 의한 촉매의 특성분석결과 사용 후 촉매(Used-cat) 표면에 $(NH_4)HSO_4$가 침적이 되었음을 확인하였다. 또한, $SO_2$에 대한 내구성이 우수한 촉매일수록 표면에 형성되는 황산염($SO_4^{-2}$)이 적게 형성됨을 확인할 수 있었다.

• 한국초지조사료학회지
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• 제32권4호
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• pp.379-386
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• 2012

In this study, the in vitro fermentation parameters of whole crop barley (WCBS-TMR) and Italian ryegrass (IRGS-TMR) silage total mixed rations were compared. A rice straw based diet (RSBD), which was a mixture of rice straw and concentrate (60:40), was used as the control. The feeds were incubated in buffered rumen fluid for 3, 6, 9, 12, 24, 48 and 72 hours at $39^{\circ}C$. At the end of each incubation period the following parameters were determined, total gas, pH, ammonia nitrogen ($NH_3$-N), volatile fatty acids (VFA) and then the acetate to propionate ratio (A/P) was calculated. The dietary treatments did not affect (p>0.05) the overall production of $NH_3$-N, gas, total VFA and all the individual VFA, with the exception of n-butyrate (p<0.001). The treatment diets significantly affected the A/P ratio (p<0.01). The control diet resulted in the lowest A/P ratios, followed by WCBS-TMR and lastly IRGS-TMR had the highest ratios. Gas production was not different between treatments, suggesting a probable similar level of digestibility when treatments are fed to animals. It can therefore be concluded from the present study that WCBS and IRGS are of almost an equivalent nutritional value when incubated in a TMR form. WCBS-TMR however resulted in lower A/P ratios than IRGS-TMR, which is indicative of a more energy efficient diet.

• 한국수산과학회지
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• 제38권6호
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• pp.347-352
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• 2005

These experiments investigated the conditioning pattern and the nitrification efficiency of a fluidized sand biofilter (FSB) for seawater application. The FSB fed artificial nutrient was fully conditioned within 22 weeks. The maximum nitrification efficiency of the FSB was achieved at a superficial water velocity (SWV) of 1.0 cm/sec. After fixing the superficial water velocity at 1.0 cm/sec, the nitrification rates of the FSB were assessed at 3 total ammonia nitrogen (TAN) loading rates (250, 500, 1,000 g TAN/$m^3$/day) and 3 water temperatures (12, 16, $20^{\circ}C$). The TAN concentration in the simulated culture tank ranged from 2.87 to 9.72 mg/L at TAN loading rate of 1,000 g TAN/$m^3$/day, while that ranged from 0.45 to 1.26 mg/L at TAN loading rate of 500 g TAN/$m^3$/day. The ranges of TAN concentration in the former were too high for aquatic organisms and those in the latter were acceptable. Therefore, the safe TAN loading rate for the FSB in seawater conditions was decided as 500 g TA/$m^3$/day. From these results, daily TAN removal rates (g TAN/$m^3$/day) of FSB under conditions of inlet TAN concentration (C, mg/L) and water temperature (T, $^{\circ}C$) were calculated by the following non-linear multi-regression equation: TAN removal rate: f(z)=-1,311.295+655.714LnT+225.775LnC ($r^2=0.962$).

• Fisheries and Aquatic Sciences
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• 제9권4호
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• pp.153-159
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• 2006

The ark shell (or 'blood clam') Scapharca broughtonii is a filter-feeding bivalve that has red blood and inhabits waters approximately 10m in depth off the southern coast of South Korea. This study was part of a larger research project investigating the causes of death and restoration of shellfish resources, which are important aquaculture products in South Korea. We examined physiological responses related to survival, respiration, excretion, and amino acid changes as a result of changes in salinity. The 9-day median lethal salinity ($LS_{50}$) was 16.5 psu with confidence limits of 14.9-18.1 psu. At $25^{\circ}C$, the oxygen consumption and ammonia-nitrogen excretion rates were increased with decreases in salinity. Although the osmolality of individuals was acclimated within 2 h at 26.4 psu and 12 h at 19.8 psu, it took more than 5 days at a salinity of 13.2 psu, whereas no individuals acclimated and all died at a salinity of 6.6 psu. Of the amino acids present in the blood, taurine and alanine increased in response to decreased salinity. Tissues of the gill and the mid-gut gland were affected by decreasing salinity. These data will provide important fundamental information for examining the causes of mass mortality of shellfish in the summer.

• 한국수산과학회지
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• 제48권3호
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• pp.275-283
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• 2015

This study compared the sensory and nutritional characteristics of mottled skate Beringraja pulchra caught off Ulleung Island (U-MS), Korea, with those caught off Daecheong Island (D-MS). Based on their trichloroacetic acid-soluble nitrogen content, free amino acid content, and taste value, the taste of intermediate weight female U-MS was superior to that of both other U-MS and D-MS. The urea content of U-MS was higher in females than males and increased in the order heavy>intermediate>light individuals. There was, however, no difference in urea content between U-MS and D-MS. The taste and flavor characterization results suggest that the level of ammonia, which was converted from urea, influenced the quality of fermented U-DS. With the exception of the light U-DS, the other U-MS exhibited no difference in terms of hardness. The total amino acid content of U-MS was higher in females than males and increased in the order intermediate > heavy > light individuals. The total amino acid content of U-MS was also higher than that of D-MS. The major amino acids of all MSs were aspartic acid, glutamic acid, leucine, and lysine.

• 한국수산과학회지
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• 제46권3호
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• pp.245-251
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• 2013

This study was conducted to compare quality characteristics of imported skate rays. The moisture content was higher in imported skate rays than in domestic mottled skate, while the protein content displayed a contrasting pattern. From measurements of the volatile basic nitrogen content, pH, viable cell counts, and urea and ammonia contents, the freshness of skate rays imported from Chile, Canada and Uruguay was considered to be inferior to domestic mottled skate, while the freshness of skate rays imported from the USA was similar. The measurement of physicochemical properties revealed that four kinds of imported skate rays were of inferior quality, as compared to domestic mottled skate.