• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.197-197
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• 2010

음식물쓰레기의 삼성분은 수분, 휘발분, 회분이며 이들이 차지하는 비율은 계절, 지역별로 다소 상이하지만 수분 약 80%, 회분3%, 휘발분 17%이다. 음식물쓰레기 전처리과정으로 이물질제거, 탈수공정이 있으며 탈수공정에서 다량의 탈리액이 발생한다. 본 연구에서는 탈리액을 데칸타를 이용하여 1차로 원심분리하여 고.액 분리한 액을 실험대상으로 하였다. 실험대상 탈리액의 물성은 BOD 78,800[mg/l], COD 41,000[mg/l], 부유물질 25,900[mg/l], 총질소 928[mg/l]이었다. 탈리액에는 기름성분(육류, 식용유등), 입자상물질등이 포함되어 있으며 이들은 난분해성 유기물질로, 이를 제거하는데 기존의 처리방법으로 많은 어려움이 있어 주요한 수질오염 발생원이 되고 있다. 예를들면 하수처리장 폭기조 수면에 유막을 형성하여 산소공급을 방해함으로 미생물번식을 방해하는 요인이 된다. 본 연구는 음식물쓰레기 탈리액의 수분, 고형분, 유분으로의 삼상분리에 관한 것이다. 유분은 에멀젼형태로 안정되게 수층에 분산되어 존재한다. 미세기포를 이용한 부상법의 경우 미세기포 표면과 유분의 화학적친화력이 낮아 기포표면에 유분이 잘 부착되지 않으며, 원심분리 방법만으로는 유분 분리효율이 낮고, 추출에 의한 분리시 추출액이 다량 소요되고 처리시간이 길며 추출액 비용이 많이 소요된다. 탈리액을 유분, 슬러지, 수분으로 분리하면 환경오염을 일으키는 주요성분을 신재생에너지 원료로 활용할 수 있다. 유분의 주성분이 동식물성 유지이므로 전처리시 산촉매를 이용 수분과 유리지방산을 제거하고 염기성촉매를 이용하여 전이에스테르화 반응을 거치면 바이오디젤인 FAME과 글리세롤으로 변환하므로 글리세롤을 분리하면 바이오디젤을 얻을 수 있다. 슬러지는 입자상 물질로 착화가 잘 되고 건조하면 발열량이 높으며 중금속등에 오염되지 않아 청정연료로 활용이 가능하다. 실험실에서의 탈리액 삼상분리방법은 다음과 같다. 탈리액 30ml당 추출액으로 노말헥산을 1ml를 가한 다음 플라스크에서 $80^{\circ}C$로 가열 후 방냉한다. 가열중 노말헥산의 손실을 방지하기 위하여 증발가스를 콘덴서에서 응축하여 플라스크로 재순환한다. 탈리액을 플라스크에서 꺼내어 원심분리기 rack에 300-400g씩 병에 각각 넣고 4,000rpm으로 30분간 운전한다. 탈리액은 상부로부터 유분층, 미세입자층, 수층, 슬러지층으로 분리된다. 각 층의 계면에서 2종의 성분이 약간 섞일 수 있다. 유분을 분리한 후 유분층 잔존물과 미세입자층, 수층 상층부의 혼합물을 취하여 50g씩 병에 넣고 3,500rpm으로 10분간 운전한 후 유분을 분리한다. 마지막으로 미세입자층만을 3,500rpm으로 10분간 원심분리한 후 유분을 따로 분리한다. 얻어진 유분은 rotary evaporator에서 $120^{\circ}C$로 가열하여 유분과 노말헥산을 분리하며 분리효율을 제고하기 위하여 감압하에서 운전한다. 분리된 유분의 고위발열량이 9,450[Kcal/kg]이었으며 원소분석 결과 탄소 74.7%, 수소 12.55%, 질소 0.08%, 유황분 0.0003%이었다. 분리된 유분의 양은 계절별로 시료별로 다르며 가을철에는 1.6-1.9%, 여름철은 1.0-1.3%이었다. 분리된 슬러지로부터 Hg, As, Cr, Cd, Pb 중금속 성분이 검출되지 않았으며 수분 2.8%, 휘발분 76.85%, 회분 7.52%, 고정탄소 12.83%이었고 원소분석결과 탄소 45.25%, 수소 7.46%, 질소 5.05%, 산소 34.39%, 유황분 0.33%이었으며 저위발열량은 4,480[Kcal/kg]이었다. 분리된 슬러지 양은 11-19% 이었다.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.4
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• pp.86-92
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• 2000

This study was conducted to determine the optimal mixing ratio of the paper mill sludge(PMS) and pig manure(PM). Since the former contains lots of total carbon and low nitrogen, it was used as carbon source. Also, dried paper mill sludge(DPMS) was added to the mixture to control the water content. The treatments was composed of four as follows, PMS-100(PM 0%+PMS 80%+DPMS 20%), PMS-85(15+65+20), PMS-70(30+50+20), and PMS-55(45+35+20). The mixtures were composted under aerobic condition in $1.25m^3$ static piles. The piles were aerated for 15 minutes per day and turned over the mixture once a week at the early stage of composting. To estimate the maturity of composts, the changes of physico-chemical properties such as temperature, pH, C/N ratio and color were monitored every week. The 25-30 and 55-60% as optimal condition of C/N ratio and moisture content were respectively recommended for effective composting by the evaluation of the changes of phsico-chemical properties for materials taken from compost files during the composting period. When the 30 and 45% of PM were mixed with PMS, the maturity time at least demanded to the stable state were shortened and the qualify of the final product was improved in a view of nutritional components.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.53-64
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• 2020

A 2㎥/d combined wastewater treatment pilot plant containing the multi-stage vertical stacking type nitrification reactor was installed and operated for more than 1 year under the operating conditions of the short-circuit nitrogen process (pH 8, DO 1mg/L and Internal return rate 4Q from nitrification to denitrification reactor). For economically the combination treatment of food wastewater and the leachate from a landfill, the optimal combination ratio was operated by adjusting the food wastewater with the minimum oil content to 5-25% of the total throughput. The main treatment efficiency of the three-phase centrifugal separator which was introduced to effectively separate solids and oil from the food wastewater was about 52% of SS from 116,000mg/L to 55,700mg/L, and about 48% of normal hexane (NH) from 53,200mg to 27,800 mg/L. During the operational period, the average removal efficiency in the combined wastewater treatment process of BOD was 99.3%, CODcr 94.2%, CODmn 90%, SS 70.1%, T-N 85.8%, and T-P 99.2%. The average concentrations of BOD, CODcr, T-N, and T-P of the treated water were all satisfied with the discharge quality standard for landfill leachate ("Na" region), and SS was satisfied after applying the membrane process. On-site leachate had a relatively high nitrite nitrogen content in the combined wastewater due to intermittent aeration of the equalization tanks and different monthly discharges. Nevertheless nitrite nitrogen was accumulated, denitrification from nitrite nitrogen was observed rather than denitrification after complete nitrification. The average input of anti-forming chemical during the operation period is about 2L/d, which seems to be economical compared to the input of methanol required to treat the same wastewater.

• Korean Journal of Environmental Biology
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• v.37 no.2
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• pp.136-143
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• 2019

This study investigates the effect of denitrified biofloc water on changes in the water quality parameters and the physiological characteristics of shrimps. Biofloc rearing water contains a large number of microorganisms and can rapidly stabilize the water quality and energy saving if reusable due to high water temperatures. Rearing water contain floating bacteria with both aerobic and anaerobic bacteria. Therefore, when the carbon source is added in limited air supply, the anaerobic state is activated and the denitrification process is possible. In this study, the denitrification water had the following properties: ammonia (6.9 mg L^-1), nitrite (0.3 mg L^-1), nitrate concentration (9.2 mg L^-1), high pH (8.42) and alkalinity (590 mg L^-1). The experimental group consisted of seawater (SW, control), a mixture of Seawater and denitrified biofloc water (DNW) in the ratio of 3:1, 1:1 and DNW only. All experiments were done in triplicate. As a result, the survival rate never changed even when 100% of the denitrification water was utilized. However, a body fluid analysis showed that creatine and BUN were increased due to index of stress and the tissue damage resulting from the high denitrified water content. Body fluid ions (Na⁺, K⁺, and Cl^-) significantly decreased as the denitrified water content increased. It was recommended that the denitrification water be mixed with a certain ratio (less than 50%) in the future as it may affect the osmotic pressure control in shrimps.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.1
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• pp.5-11
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• 2024

Objective of this study was to evaluate the effect of organic fertilizer application on yield, soil chemical properties and soil organic carbon (SOC) in Korean cabbage cultural field. The experimental treatments consisted of none fertilizer (NF), NPK (inorganic fertilizer, N-P₂O₅-K₂O : 320-78-198 kg ha^-1), Organic fertilizer (OF 50, 100, 150% on application rate of standard 110 kg ha^-1 as N, topdressing: 210 kg ha^-1 as inorganic fertilizer). In experimental results, the growth characteristics and yields were not significantly different among the treatments. There was no significant difference in soil pH, available phosphate, ammonium nitrogen and exchangeable potassium, while organic matter, electrical conductivity and nitrate nitrogen were increased when organic fertilizer application. Also, SOC was increased with the application of organic fertilizers. These results showed that pre-application of organic fertilizer might be effective in a carbon storage in the field soil cultivating Korean cabbage.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.2
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• pp.84-92
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• 2010

This research was conducted to investigate physico-chemical characteristics of municipal solid waste (MSW) generated from T City, Gangwon-do and leaching characteristics of the incineration ash. From the results, bulk density of MSW in T city was $231kg/m^3$. Combustible and incombustible components were in 94.0% and 6.0%, respectively. Food waste and papers in combustible component occupied 32.3% and 41.2%. Water, volatile solids, and ash content were 41.3%, 50.5%, and 8.2%. C, H, O, N, S, and Cl showed 51.4%, 6.3%, 26.7%, 1.1%, 0.2%, 0.5%, respectively. Low heating value (2,704 kcal/kg) of T city was similar to 2,764 kcal/kg of Chuncheon and was 1,000 kcal/kg higher than 1,467~1,584 kcal/kg of the past Kuro-gu and Koyang city. The specification of leaching characteristics of the incineration ash were within the Korean regulation standard.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.39-48
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• 2019

Objective of this study was to evaluate an optimum biochar application rate and estimate the carbon sequestration based on the soil chemical properties and growth responses for biochar application during tomatoes cultivation. The treatments consisted of control as recommended application rates of fertilizers, 0.01%, 0.03%, 0.05%, and 0.07% of biochar application(w/w, biochar:soil). For effects of soil chemical properties, the $NO_3-N$contents in the soil were peaked at 9 days after transplanting. But there was not significant difference(p>0.05) among the treatments during cultivation periods. However, $NH_4-N$ contents in the biochar treatment were lower than the control until 14 days of transplanting. $P_2O_5$ contents in the biochar treatments were lower than that of the control until 19 days after transplanting except 0.01% of biochar application plot. $K_2O$ contents in soils treated with 0.01% and 0.03% of biochar were higher until 6 days after transplanting than that in the control. For N use efficiency of biochar application, it was observed that the 0.05% biochar application plot was highest among the treatments. The highest carbon sequestration was estimated at $2.83mg\;kg^{-1}$ for 0.03% of biochar application. However, it is considered that the optimum biochar application rate was 0.05% for tomato cultivation, considering the growth characteristics and yield components.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.142-148
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• 1997

Mrthylov~orits sp. starin SSl, a restricted facultative methylotrophic bacterium. growing on methanol was found to produce small amount of extracellular polysaccharide (EPS) under the optimal growth conditions, while it produced large amount of the polysaccharide under nitrogen limihtion. The optimal ratio of carbon to nitrogen for EPS production were found to be 5.2. The optimal temperature and pH for EPS production were 30^{\circ}C.$ and 6.5, spectively. The EPS consisted of carbohydrate, protein and small amount pyruvic acid. The reducing sugars in the EPS consisted mainly of glucose and a small amount of mannose. The EP!; treated with ethanol (EPSae) was found to have several properties different from those of the EPS which was not treated with ethanol (EPSbe); the EPSae contained no pyruvic acid. It also contained less protein and showed much lower viscosity than the EPSbe. The viscosity of EPSbe was very sensitive to NaCl and decreased t;harply upon exposure of the polysaccharide to even 0.5% (wiv) NaCl solution. The viscosity, however, was increased irreversibly upon exposure of the saccharide to high temperature. The molecular weight of EPS was estimiited to be $2.5{\times}$10^6$ - $3.5{\times}*$10^6$ using Sepharose hB column chromatography. Scanning electron microscopy revealed that the lyophilized EPSbe and EPSae have a structure of thread-like fibers and a mesh-like structure resembling bee-hive, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.121-126
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• 1999

In order to degrade chitin by enzymatic hydrolysis, it is required from screening highly active deacetylase. To this end, we examined three fungal strains and it turned out that Mucor rouxii produced highly active deacetylase, this enzyme exhibited the highest enzymatic activity against colloidal chitin. The conditions for growing Mucor rouxii are as follows; the effective carbon source, nitrogen source, adequate initial pH, temperature and incubation time were $2\%$ glucose, $1.33\%$ yeast extract, $0.66\%$ pepton, 4.5, $25{\pm}2^{\circ}C$ and 48hr, respectively. The optimum pH and temperature for purified enzyme activity were 5.5 and $40^{\circ}C$, respectively. The purified enzyme was stable at pH ranging from 4.5 to 5.5. However, the enzyme activity was decreased to less than $50\%$ at pH blow 45 and above 7.5. At temperatures above $50^{\circ}C$, the enzyme activity was decreased remarkably. The enzyme was inhibited by LiC1, $HgCl_2$, and $BaCl_2$, but stimulated by $CaCl_2$ and $ZnC1_2$, The activity of purified enzyme was increased by L-cysteine and 2-mercaptoethanol, while decreased by O-phenanthroline, p-CMB, EDTA, and iodoacetate. The $K_m$ and the $V_{max}$ value of purified enzyme were $1.2\%$ and 59.5 U/mg, respectively. The deacetylation activity of purified enzyme was not detected at optimal reaction condition when chitin particle suspension was used.

• Journal of Mushroom
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• v.20 no.3
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• pp.168-172
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• 2022

This study was conducted to investigate the optimum supplementation ratio when replacing cotton seed meal with rapeseed meal for cultivating oyster mushrooms. The chemical properties among the treatments were pH 4.5~4.7, total carbon content was 46.3~46.5%, total nitrogen content was 1.6~1.7%, and carbon-nitrogen ratio was 27.0~27.8. These did not differ significantly from the control. Mycelial growth was 85.1 mm (Heuktari), and 72.8 mm (Suhan-1Ho) in medium containing 5% rapeseed meal, with no significant difference in mycelial density between cultivars. Fruiting body characteristics are as follows: In 'Heuktari', the color of the pileus was darker than control with an L value of 32.5, and pileus thickness and diameter were 3.2 mm and 27.6 mm, respectively. Stipe length and diameter were 86.0 mm and 9.1 mm, respectively. Valid stipe number per bottle (1,100 cc) was 25.9, and a yield of 189.7 g/1,100 cc was recorded in mixed medium containing 5% rapeseed meal (higher than control). In mixed medium containing 10% rapeseed meal, the yield was 184.5 g/1,100 cc (comparable to control). In 'Suhan-1Ho', supplemented with 5% rapeseed meal, pileus color was darker than control color, with an L value of 28.8. Pileus thickness was 4.5 mm. Stipe diameter was 12.3 mm (higher than control), and yield was 145.5 g/1,100 cc (comparable to control).