• 대한환경공학회지
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• 제34권1호
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• pp.42-48
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• 2012

본 연구에서는 미세기포 액막화 부상조를 이용하여 인 제거에 관한 연구를 실시하였다. 미세기포 액막화 부상조는 기체용해탱크를 이용하여 부상 전 기 액을 충분히 용해시킨 후 일정한 저 압력으로 동일한 미세기포를 생성하도록 하는 방법을 사용하였다. $A_2O$ 공정과 m-$O_3$(미세기포 생성장치와 오존용해탱크가 결합된 공정)복합공정을 거친 2차 유출수를 인 제거 공정의 유입수로 사용하였으며, 원수의 T-P 농도가 2.89 mg/L일 때, 8%의 Alum을 30 mg/L의 농도로 주입하였을 경우 T-P 제거율이 94%를 나타내었고, T-P의 방류수수질기준인 0.2 mg/L 이하를 만족시키는 것으로 조사되었으며, 계절에 따른 수온 변화는 T-P 제거 특성에 영향을 주지 않았다. SS의 유입농도가 1.0 mg/L 이상일 시 SS가 응집공정 내의 seed 역할을 하여 평균 T-P의 제거율이 97% 이상 되는 것으로 조사되었고, 부상스컴을 50% 반송할 경우, 부상스컴 내에 포함되어 있는 응집제 성분 Al이 주입되는 응집제의 역할을 보조하여 오염물질의 응집효율을 극대화 시키는 것으로 조사되었다. 이러한 조건에서 T-P의 방류수 수질기준 0.2 mg/L 이하를 만족하는 0.18 mg/L의 농도를 나타내는 것으로 조사되었다.

• 유기물자원화
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• 제29권4호
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• pp.77-86
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• 2021

본 연구에서는 유기성폐자원에너지 인센티브제도의 기초자료로 활용하고자 음식물폐기물, 음폐수 및 다양한 유기성폐기물이 처리되는 혐기소화조의 운영방식의 물질수지와 에너지수지 산정 결과를 통하여 에너지효율을 평가하고자 한다. 바이오가스화 시설 11개소의 물질수지 분석 결과 유기성폐기물을 제외한 반입물 중 공정수 21.1%, 시상수 25.7 % 다량 투입되는 것을 확인하였다. 그에 따라 연계처리수의 전체 유출물의 87.6 %를 차지하였다. 또한 총 유입물량의 15.7 %가 바이오가스로 전환되며, 총고형물(TS)가 평균 22 %임을 감안할 때 평균 75 %의 물질 전환율을 확인하였다. 에너지수지 분석 결과, 유입물의 잠재에너지 대비 바이오가스 열량을 분석하여 에너지 전환율은 평균 78.5%을 확인하였다. 바이오가스를 생산하기 위한 외부에너지원을 포함한 바이오가스 생산효율은 평균 69.4 %이며, 미이용된 유출에너지를 적용한 바이오가스 플랜트 효율은 평균 58.9 %로 나타났다.

• Journal of Animal Science and Technology
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• 제49권2호
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• pp.161-170
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• 2007

본 연구에서는 생산성이 인정된 모돈 F1(YL)에 종료웅돈(Terminal Sire)으로 Duroc종 이외에 생산성 저하에 많은 영향을 미치지 않을 것으로 판단되는 최종 종료웅돈(Terminal Sire) Berkshire종과 Berkshire×Duroc(F1)을 YL(♀) 교배시켜 생산된 비육돈(YLD, YLB, YLBD)의 성장과 육질을 비교 분석 하였다. 성장형질에서는 YL(♀)×BD(♂)가 YL(♀)×D(♂)보다 우수하였으며, 조사된 성장형질 전체에서 유의적인 차이(p<0.05)를 보였다. 육질에서도 pH, 보수력, 육색이 다른 비육돈 보다 유의적으로(p<0.05) 우수하였고, 돼지 육질의 표준이 되는 등심조지방 함량에서 YL(♀)×BD(♂)가 유의적으로 우수하였다. 교배조합별 육색에서는 YL(♀)×BD(♂)가 대체로 명도와 적색도가 높았으며, 지방산 조성에 있어서는 불포화 지방산의 비율이 높은 것으로 나타났다. 따라서, 성장형질에서는 YL(♀)×BD(♂)가 비교 대상의 교배조합에 비해 우수하였으며, 육질에서도 YL(♀)×D(♂) 보다 좋거나 같아 비육돈 교배조합(YLBD)으로서의 이용가치가 있을 것으로 사료된다. 하지만 본 연구의 경우 경남 첨단양돈연구소의 계통조성이 완료된 American Berkshire종을 이용하여 경남의 경우 경남 첨단양돈연구소를 활용하여 별도의 비용이 없이 YLBD를 생산이 가능하겠으나, 다른 지역의 경우 Berkshire의 계통 조성하여 활용할 경우 기존의 종료웅돈 Duroc종을 계통 조성하는 비용만큼 더 소요될 것이라 사료된다.

• 한국습지학회지
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• 제22권1호
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• pp.1-7
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• 2020

비점오염은 수계에 악영향을 끼치며 그 영향은 점차 커지고 있다. 이러한 비점오염을 관리하기 위해 정부에서는 LID(Low Impact Development) 시설의 연구와 다양한 효율평가를 시행하고 있다. 본 연구에서는 다양한 LID 시설 중 실제 설치된 투수 블록 시설의 강우 유출 억제를 위한 유출 저감율, 저류 강우량 분석 및 유출 지연시간 그리고 최대 유입 및 유출의 저감율을 분석했으며, 그 결과를 각 시설 간 비교했다. 불투수블록, 필터형 투수블록, 틈새형 투수블록 순서대로 분석 결과 저감 효율이 높게 나타났으며, 이를 통해 강우강도-유출지연시간간의 관계를 나타낸 그래프를 제시하였다. 이 그래프를 통해 앞으로 설계 시, 본 시설과 유사한 투수블록 시설의 재현 기간에 따른 시설 용량 선정 등의 설계에 도움을 줄 수 있으리라 생각한다.

• 상하수도학회지
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• 제26권6호
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• pp.833-840
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• 2012

This study aimed to investigate growth rate and nutrient removal efficiency of Chlorella vulgaris according to nitrogen sources and frequency of pH adjustment. Nitrogen and phosphorus removal efficiencies were evaluated in the three different conditions using $NO_3{^-}$, $NH_4{^+}$ as a sole nitrogen source and mixed condition. Initial nutrient concentrations in artificial wastewater were 30 mg-N/L and 3 mg-P/L similar to secondary wastewater effluent. When nitrogen source was $NO_3{^-}$, there was no inhibition on the growth of C. vulgaris with adjusting pH every 24 hr while growth inhibition occurred with $NH_4{^+}$ caused by pH drop. N, P removal efficiencies were no significant depending on the nitrogen sources. As pH was adjusted to 7 by pH-stat, growth rate and nutrient removal efficiencies were increased compared to adjusting pH every 24 hr, however, growth rate and nutrient removal efficiencies were no significant depending on the nitrogen sources.

• Asian-Australasian Journal of Animal Sciences
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• 제13권10호
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• pp.1399-1406
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• 2000

A continuous culture study was conducted to determine the impact of ruminal degradable soy protein (S-RDP) level and dilution rate (D) on growth of ruminal non-structural carbohydrate-fermenting microbes. Corn starch, urea and isolated soy protein (ISP) were used to formulate three diets with S-RDP levels of 0, 35 and 70% of total dietary CP. Two Ds were 0.03 and $0.06h^{-1}$ of the fermenter volume in a single-effluent continuous culture system. As S-RDP levels increased, digestibilities of dietary dry matter (DM), organic matter (OM) and crude protein (CP) linearly (p=0.001) decreased, whereas digestion of dietary starch linearly (p=0.001) increased. Increasing D from 0.03 to $0.06h^{-1}$ resulted in decreased digestibilities of dietary DM and OM, but had no effect on digestibilities of dietary starch (p=0.77) and CP (p=0.103). Fermenter pH, the concentration of volatile fatty acids (VFA) and daily VFA production were unaffected (p=0.159-0.517) by S-RDP levels. Molar percentages of acetate, propionate and butyrate were greatly affected by S-RDP levels (p=0.016-0.091), but unaffected by D (p=0.331-0.442). With increasing S-RDP levels and D, daily bacterial counts, daily microbial N production (DMNP) and microbial efficiency (MOEFF; grams of microbial N produced per kilogram of OM truly digested) were enhanced (p=0.001). The increased microbial efficiency with increasing S-RDP levels is probably the result of peptides or amino acids that served as a stimulus for optimal protein synthesis. The quantity of ruminal degradable protein from soy proteins required for optimum protein synthesis of non-structural carbohydrate-fermenting microbes appears to be equivalent to 9.5% of dietary fermented OM.

• 한국습지학회지
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• 제9권1호
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• pp.47-60
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• 2007

The rapid development of economy in China at the expense of consuming huge amount of energy and resources, water resource in particular, which has resulted in the production and discharge of increasing amount of wastewater to the water environment. In order to effectively control the increasing water pollution trend, the State Council has stipulated that all the cities with population over 500,000 should reach wastewater treatment rate of 60% by 2005, and all the cities should reach the rate of 60% by 2010, of which Capital Beijing and all the province capital cities and important tourism cities should reach 70% then. By the end of 2005, of the 661 cities in China, 393 have built and operated municipal wastewater treatments with a total number of 790 sets, total treatment capacity of $80.91{\times}106m^3/d$ and total treatment rate of > 48%. Other 73 cities have started the construction of municipal wastewater treatment plants, and other 168 cities have started to prepare, planning and design of wastewater treatment plants. Most of municipal wastewater treatment plants in big cities in China operate normally and perform well with good quality of effluent in terms of wastewater treatment train, but the sewage sludge treatment is usually poor with big problems. It has been found that the small scale WWTPs using activated sludge process in the towns are usually operated and maintained abnormally because of lack of fund, skilled operators and energy. It is therefore suggested that the small scale MWWTPs in small cities and towns adopt appropriate technologies, of which the most available ones are multi-stage ponds, constructed wetlands and the combination of them for further purification and reuse of treated wastewater.

• Membrane and Water Treatment
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• 제11권4호
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• pp.303-312
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• 2020

This study aims to investigate at a laboratory scale fluorides removal from an industrial wastewater having excessive F^- concentration through a hybrid process combining neutralization and membrane separation. For the membrane separation operation, both Reverse Osmosis (RO) and Nanofiltration (NF) were investigated and confronted. The optimized neutralization step with hydrated lime allowed reaching fluoride removal rates of 99.1± 0.4 %. To simulate continuous process, consecutive batch treatments with full recirculation of membrane process brines were conducted. Despite the relatively high super saturations with respect to CaF₂, no membrane cloaking was observed. The RO polishing treatment allowed decreasing the permeate fluoride concentration to 0.9± 0.3 mg/L with a fluoride rejection rate of 93± 2% at the optimal transmembrane pressure of around 100 psi. When NF membrane was used to treat neutralization filtrate, the permeate fluoride concentration dropped to 1.1± 0.4 mg/L with a fluoride rejection rate of 88± 5% at the optimal pressure of around 80 psi. Thus, with respect to RO, NF allowed roughly 20% decrease of the driving pressure at the expense of only 5% drop of rejection rate. Both NF and RO permeates at optimal operating transmembrane pressures respect environmental regulations for reject streams discharge into the environment.

• 상하수도학회지
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• 제24권4호
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• pp.377-386
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• 2010

To identify operating parameters of the up-flow filtering system, which is available to discharge filtering residue after the rain, developed for treatment of urban storm runoff, lab scale test was carried out. Removal efficiency of SS was 68.7%, 62.2%, and 58.6% at the area roading rate of 2.46m/h, 4.68m/h, and 10m/h, respectively, filtering device is desirable to operate at the lower than 4.68m/h of area roading rate to get higher level of 60% SS removal efficiency. The removal efficiency of SS was 57.1% ~ 68.7% at the raw water SS of 100mg/L ~ 600mg/L, and the SS in treated water was maintained at the constant level through the elapsed time. It is indicate that filtering device can guarantee a certain level of effluent water quality at various raw water quality. The removal efficiency of SS to the depth of filter media was 68.3%, 78.6% at the filter depth of 10 cm, 20cm respectively. The final treated water quality was showed 30.2mg/L of CODMn, 1.60mg/L of TN and 0.25mg/L of TP. The average removal efficiencies by filtering device developed in this research were recorded slightly lower levels than other research. The main reason of these results were the first, the filter depth of the media used in this test was shallow, the second, the kind of filter media in discharge port of residue. More research to kind of filter media, filter packing rate, select of media for residue discharge port should be go on to produce optimum operating condition. The result of this study would be valuable for the application of filtration device to control of urban storm water.

• 한국물환경학회지
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• 제22권2호
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• pp.222-229
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• 2006

The treatment performance and operational parameters of a tertiary wastewater treatment process a biological filtration system were investigated. The biological filtration system consisted of a nitrification filter (Fiter 1) and a polishing filter with anoxic and aerobic parts (Filter 2). SS, T-C-BOD, and T-N in effluent were kept stable at less than 3, 5 mg/L, and 5 mgN/L, respectively, under a HRT in Filter (filter-bed) of 0.37~2.3 h. T-N at the outlet of Filter 2 were about 1~5 mgN/L under the condition of LV of 50~202 m/d. In Filter 2, denitrification was accomplished under LV of 50~168 m/d in a 1 m filter-bed. However, the denitrification capacity reached the maximum when the linear velocity was increased to 202 m/d. Relationship between increase in microorganism and headloss was clearer in Filter 2. As a result, the denitrification rate increased from 1.0~2.3 kgN/($m^3-filter-bed{\cdot}d$) as the headloss increased. The COD removal rate was 6.0~9.6 kgCOD/($m^3-filter-bed{\cdot}d$) when operated with Filters 1 and 2. These results mean that captured bacteria contributed a part of COD consumption and denitrification. The maximum nitrification and denitrification rate was 0.5 and 4 kgN/($m^3-filter-bed{\cdot}d$) in Filter 1 and 2.The ratio of backwashing water to the treated water was about 5~10 %. In Filter 1, wasted sludge in backwashing was only 0.7~5.3 gSS/($m^3$-treated water). In Filter 2, added methanol was converted into sludge and its value was 8.0~24 gSS/($m^3$-treated water). These results proved that this process is both convenient to install as tertiary treatment and cost effective to build and operate.