• 대한토목학회논문집
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• 제8권3호
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• pp.129-138
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• 1988

본(本) 연구(硏究)에서는 잔자갈을 충전(充塡)한 간접폭기방식(間接曝氣方式) 침지여상(浸漬濾床)의 설계(設計)나 운전에 합리성(合理性)을 부여하기 위해, 폭기조(曝氣槽)에서 침지여상(浸漬濾床)으로의 산소공급(酸素供給) 특성(特性) 및 잔자갈의 입경(粒徑), 순환수(循環水)의 수량부하(水量負荷), $BOD_5$ 용적부하(容積負荷) 변화에 대한 처리효율(處理效率)을 검토하였다. 실험(實驗)은 $20^{\circ}C$를 유지한 침지여상(浸漬濾床)의 하부(下部)에 합성하수(合成下水)를 상향류(上向流)로 연속주입(注入)하였고, 동시(同時)에 포기조에서 충분히 포기된 물을 침지여상(浸漬濾床)에 상향류(上向流)로 순환(循環)시키면서 수행되었다. 실험결과(實驗結果) 가장 적당한 잔자갈의 입경(粒徑)은 11 mm 정도였으며, 설계(設計) 및 운전을 위해서는 잔자갈의 표면적부하(表面的負荷)보다는 침지여상(浸漬濾床)의 용적(容積)을 기준으로 하는 것이 타당하며, 90% 이상의 $BOD_5$ 제거율을 얻기 위해서는 BOD 용적부하율(容積負荷率)을 $1.0kg-BOD_5/m^3{\cdot}d$ 이하로 운전하여야 하며, 이때 순환수(循環水)($DO7.2mg/{\ell}$)의 수량부하(水量負荷)는 $189m^3/m^3{\cdot}d$ 이상으로 유지시켜야 할 것으로 나타났다. 또 본실험(本實驗) 범위내에서 반응속도계수(反應速度係數) $K_1$은 순환수(循環水)의 수량(水量) 부하(負荷) 및 잔자갈의 입경(粒徑)과 밀접한 관계(關係)가 있음을 알았다.

• 상하수도학회지
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• 제19권1호
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• pp.47-52
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• 2005

This study was conducted to evaluate the performance of submerged hollow fiber MF processes to treat secondary wastewater for water reuse. Specifically, membrane productivity and filtrate water quality were investigated under various operating conditions (i.e. flux, recovery, and backwash rate) at pilot-scale. Membrane fouling became more severe with increasing flux and recovery, suggesting that low flux operation (< 25 LMH) was desirable. At high flux operating(> 37.5 LMH), increasing backwash rate showed only limited success. The biofouling, quantified by PEPA and BFHPC, was also significant in wastewater reclamation, and biogrowth control by chlorine, were necessary to improve membrane productivity. Filtrate water qualities are in good compliance with water reuse regulations regardless of operating conditions (flux, recovery and backwash rate). Particle (e.g. turbidity) removal ranged from 89 to 98%, while only 11 to 21% of organics (e.g. NPDOC) were removed by MF membrane. Only small improvement in biostability (e.g. AOC) was achieved by MF system, and thus, without post disinfection, significant microorganisms might be present in the filtrate due to regrowth. Lastly, in order to further investigate pathogen removal, controlled microbial challenge tests were performed by monitoring Giardia, Cryptosporidium, bacteria and virus, and showed relatively good microbial removal.

• 한국환경농학회지
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• 제12권1호
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• pp.35-40
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• 1993

담수토양중 diazinon의 거동에 미치는 토양유기물의 영향을 알아보기 위하여 담수토양에 토양유기물분획인 humin, humic acid, fulvic acid 와 diazinon을 처리하여 각 부식물질의 농도별 (0.1%, 0.5% 1.0%) diazinon 1.8ppm과 5.0ppm의 흡착률을 조사한 주요결과는 다음과 같다. 1. 1.8ppm diazinon의 흡착률은 humin > FA > HA의 순으로 많았고, 최대흡착률은 1.0% humin 첨가구에서 12.4%, 1.0% HA 첨가구에서 10.44%, 1.0% FA 첨가구에서 11.86% 이었다. 2. 5ppm diazinon의 흡착률은 1.0% humin 첨가구에서 10.21%, 1.0% HA 첨가구에서 10.4%, 1.0% FA 첨가구에서 10.64%를 보였다. 즉, diazinon의 첨가량 증가는 흡착률에 영향을 미치지 못하였다. 3. 부식물질별 diazinon의 흡착경향은 humic acid와 fulvic acid에서는 4시간 이내에 최대흡착률을 보였으나, humin에서는 4시간 이후에도 계속 흡착이 이루어 졌다. 4. 부식물질의 농도가 증가함에 따라 diazinon의 흡착률도 증가하였으며, humin 처리구에서 그 경향이 가장 뚜렷하였다.

• Membrane and Water Treatment
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• 제8권5호
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• pp.499-515
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• 2017

The purpose of this study was to investigate membrane fouling caused by microalgal cells in submerged membrane systems consisting of polymeric and ceramic microfiltration membranes. In this study, one polymeric (flat-sheet, pore size: $0.2{\mu}m$) and two ceramic (flat-sheet, pore size: $0.2{\mu}m$ and cylindrical, pore size: $1{\mu}m$) membranes were used. Physical cleaning was performed with water and air to determine the potential for reversible and irreversible membrane fouling. The study results showed that substantial irreversible membrane fouling (after four filtration cycles, irreversible fouling degree 27% (cleaning with water) and 38% (cleaning with air)) occurs in the polymeric membrane. In cleaning studies performed using water and air on ceramic membranes, it was observed that compressed air was more effective (recovery rate: 87-91%) for membrane cleaning. The harvesting performance of the membranes was examined through critical flux experiments. The critical flux values for polymeric membrane with a pore size of $0.20{\mu}m$ and ceramic membranes with a pore size of $0.20{\mu}m$ and $1{\mu}m$ were ${\leq}95L/m^2hour$, ${\leq}70L/m^2hour$ and ${\leq}55L/m^2hour$, respectively. It was determined that critical flux varies depending on the membrane material and the pore size. To obtain more information on membrane fouling caused by microalgal cells, the characterization of the fouled polymeric membrane was performed. This study concluded that ceramic membranes with a pore size of $0.2-1{\mu}m$ in the submerged membrane system could be efficiently used for microalgae harvesting by cleaning the membrane with compressed air at regular intervals.

• 멤브레인
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• 제22권6호
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• pp.450-460
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• 2012

스펀지 형태의 담체가 첨가된 침지형 막결합 연속회분식 생물반응기에서 담체가 제거효율과 여과성능에 미치는 영향을 조사하였다. 담체는 반응기 부피 기준으로 각각 5%, 10% 및 20% 첨가하였고, 담체를 첨가하지 않은 반응기를 대조군으로 하였다. COD, T-N 및 T-P에 대한 제거효율은 담체 첨가 유무에 관계없이 큰 차이가 없었다. 그러나 담체를 첨가한 경우, 첨가하지 않은 경우에 비해 조업시간에 따른 막간차압(TMP)은 매우 서서히 증가하였다. 이러한 결과는 폭기에 의해 상승하는 담체가 막 표면과 충돌하게 되고, 이때 막 표면에 형성된 케이크 층을 제거시키기 때문이다. 결론적으로 담체가 첨가된 막결합형 연속회분식 생물반응기는 담체가 없는 반응기에 비해 여과성능이 크게 개선되어, 폐수처리에 효과적으로 활용될 수 있을 것이다.

• 멤브레인
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• 제27권1호
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• pp.77-83
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• 2017

무기실리카 입자로 구성된 고탁도 원수를 처리하는 침지식 정밀여과 운전에서 휴민산과 2가 양이온의 존재유무에 따라 시간에 따른 파울링 저항을 관찰하였다. 공기폭기로 인한 무기실리카 입자의 파울링 감소효과는 휴민산과 칼슘이 혼합으로 존재 시 감소하였다. 파울링층의 전자현미경 관찰결과 칼슘의 존재 시 휴민산의 무기실리카 입자 표면흡착이 관찰되었다. 이는 멤브레인 표면에 조밀한 파울링층을 형성시켜 공기폭기 효과를 감소시킨 것으로 판단된다. 용액의 조성에 따른 고탁도 원수의 탁도 제거율에는 큰 변화가 없었으나 공기폭기량에 따라 칼슘과 무기실리카 입자의 혼합 존재 시 유기물질의 제거율은 80% 이상으로 증가하였다. 이는 공기폭기 하에 무기실리카 입자 표면에 흡착된 일부 휴민산들이 멤브레인 표면으로부터 함께 역수송 되어 유기물질 제거율을 증가시킨 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제23권7호
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• pp.1004-1014
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• 2013

Six nonpathogenic fungal strains isolated from alkaline soils of Buenos Aires Province, Argentina (Acremonium murorum, Aspergillus sidowii, Cladosporium cladosporoides, Neurospora tetrasperma, Purpureocillium lilacinum (formerly Paecilomyces lilacinus), and Westerdikella dispersa) were tested for their ability to produce keratinolytic enzymes. Strains were grown on feather meal agar as well as in solid-state and submerged cultures, using a basal mineral medium and "hair waste" as sole sources of carbon and nitrogen. All the tested fungi grew on feather meal agar, but only three of them were capable of hydrolyzing keratin, producing clear zones. Among these strains, P. lilacinum produced the highest proteolytic and keratinolytic activities, both in solid-state and submerged fermentations. The medium composition and culture conditions for the keratinases production by P. lilacinum were optimized. Addition of glucose (5 g/l) and yeast extract (2.23 g/l) to the basal hair medium increased keratinases production. The optimum temperature and initial pH for the enzyme production were $28^{\circ}C$ and 6.0, respectively. A beneficial effect was observed when the original concentration of four metal ions, present in the basal mineral medium, was reduced up to 1:10. The maximum yield of the enzyme was 15.96 $U_c/ml$ in the optimal hair medium; this value was about 6.5-fold higher than the yield in the basal hair medium. These results suggest that keratinases from P. lilacinum can be useful for biotechnological purposes such as biodegradation (or bioconversion) of hair waste, leading to a reduction of the environmental pollution caused by leather technology with the concomitant production of proteolytic enzymes and protein hydrolyzates.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권6호
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• pp.12-21
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• 2017

A pot experiment was conducted to investigate the transfer of As and cationic heavy metals (Fe, Mn, Zn, Cd and Pb) from soil to rice plant in soil condition with submerged and drained. During the ninety-day monitoring period for soil solution, solubility of reducible elements such as As, Fe and Mn in submerged condition were higher than that of Zn. On the contrary, concentration of Zn in drained condition was higher than that of reducible elements. The concentration of As, Cd, Pb and Zn in rice plant (root, stem, leaf and grain) showed similar pattern with soil solution. The As concentration in each part of rice plant, which cultivated in drained condition, measured 56%~94% lower than those in submerged condition. However, the contents of cationic heavy metals (Cd, Pb and Zn) were represented the opposite result with As. These results are due to mobility of As and cationic heavy metals under different soil drainage conditions which represent oxidation and reduction. Thus soil drainage control can be used as acceptable passive treatment methods to reduce transfer of inorganic contaminants from soil to rice plant. However more detailed examination on soil condition conversion is needed, because yield of rice was decreased when it cultivated in drained condition only. It also needed when soil is contaminated by As and cationic heavy metal because single drainage condition cannot reduce transfer of both kinds of contaminants all.

• 상하수도학회지
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• 제13권1호
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• pp.81-94
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• 1999

This study aims at a proposal of the plan that can improve raw water quality by an experimental study using influent water of Nak-dong river, which has been used as raw water for drinking in U-city, through the establishment of the submerged biofilter process PILOT PLANT of media packing channel method. From the analysis of removal efficiency for each water quality item of the collected sample, following results are obtained. First of all, the removal rate of suspended material, BOD, COD, T-N, TOC, turbidity, and $NH_3$ -N appear 82%, 78%, 42%, 15%, 57%, 43%, 54%, and 55% respectively and it is known that the submerged biofilter process of media packing channel method takes effects on water quality improvement from the above analysis results of water treatment efficiency. And the analyzed results for water temperature, residence time, and activities of microorganism, which can be the factors affect on water quality improvement, are as follows. 1) The removal rate variation of SS, BOD, and COD attendant on water temperature change is examined and it is known that the removal rate increases at $13^{\circ}C$ or above. 2) The removal rate of SS, BOD, and COD attendant on residence time is most active in the range of 0~18hr, 0~1.8hr, 0~2.7hr respectively, so it is found that the removal rate becomes smaller after 2.7hr. 3) From the examination of microorganism activity with the abundance of normal bacteria, it is found that the floating bacteria decrease as the flow distance from raw water inflow point of PILOT PLANT increases, and the adhesive bacteria have no concern with the flow distance. And it its known that the biomass of fine algae decreases as the flow distance from the raw water inflow point of PILOT PLANT increases from the examination with Chl-a.

• 상하수도학회지
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• 제7권1호
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• pp.37-45
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• 1993

This research was performed to examined the applicability of a fixed-biofilm process for the wastewater treatment of military installations. Utilizing plastic net media, synthetic wastewater-average $BOD_5$ cocentration was $192mg/l$ treated in the three sets of reactors that have 8 hours, 6 hours, and 4 hours of hydraulic retention time. The results of this experiment showed that the biofilm was not detached easily, and the reactor was not closed by excess biomass. The average soluble $BOD_5$ concentrations of effluent were $6.0mg/l$ with 8 hours of retention time, $11.3mg/l$ with 6 hours of retention time, and $19.4mg/l$ with 4 hours of retention time. Especially it was reduced to $5.7mg/l$ in the second stage reactor with 4 hours of retention time. These resulted that the fixed-biofilm process could be adapted for the treatment of military installation wastewater.