• Applied Biological Chemistry
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• 제46권1호
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• pp.1-6
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• 2003

본 연구는 폐수 중의 질소 제거를 위한 생물학적 처리용 미생물 개발을 위한 목적으로 질소의 산화 능력이 뛰어난 균주를 분리하였다. 분리된 세균 중에서 질소 산화능과 생육 속도가 뛰어난 CH-N 균주를 선별하였으며, 생리, 생화학적 특성 조사에 의해 Bacillus sp로 추정되어 Bacillus sp. CH-N이라 명명하였다. 분리 균주는 0.5% glucose가 포함된 초기 pH가 7,0인 암모니아 및 아질산성 질소 함유 배지에서 30시간 배양 후 각각 85%와 90%의 암모니아성과 아질산성 질소의 감소율을 나타내었다. 폐수 및 생활하수에 분리 균주를 이용한 결과, 수질 속의 암모니아성 질소가 단시간에 크게 감소시키는 효과를 확인하였다. 균주를 고정시킨 담체의 질소산화 효과를 시험하고자 Bacillus sp. CH-N을 고정시킨 세라믹 담체를 이용한 결과, 배양 2일 후에는 암모니아성 질소가 전부 제거되었다.

• Environmental Engineering Research
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• 제25권1호
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• pp.114-122
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• 2020

This study was aimed at using the Central Composite Design (CCD) and Box-Behnken Design (BBD) to compare the efficiency and to elucidate the main interacting parameters in the upflow anaerobic sludge blanket (UASB) reactor, namely: Organic Loading Rate (OLR), Hydraulic Retention Times (HRT) and pH at a constant temperature of 35℃. Optimum HRT (15 h), OLR (3.5 kg.m^-3.d^-1) and pH (7) resulted in biogas production of 5,800 mL/d and COD removal of 80.8%. BBD produced a higher desirability efficiency of 94% as compared to the CCD which was 92%. The regression quadratic models developed with high R² values of 0.961 and 0.978 for both CCD and BBD, respectively, demonstrated that the interaction models could be used to pilot the design space. BBD model developed was more reliable with a higher prediction of biogas production (5,955.4 ± 225.3 mL/d) and COD removal (81.5 ± 1.014%), much close to the experimental results at a 95% confidence level. CCD model predictions was greater in terms of COD removal (82.6 ± 1.06% > 80.8%) and biogas production (4,636.31 mL/d ± 439.81 < 5,800 mL/d) which was less than the experimental results. Therefore, RSM can be adapted for optimizing various wastewater treatment processes.

• 상하수도학회지
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• 제27권4호
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• pp.413-428
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• 2013

In this study, Ant Colony Algorithm(ACO) was used for optimal model. ACO which are metaheuristic algorithm for combinatorial optimization problem are inspired by the fact that ants are able to find the shortest route between their nest and food source. For applying the model to water distribution systems, pipes, tanks(reservoirs), pump construction and pump operation cost were considered as object function and pressure at each node and reservoir level were considered as constraints. Modified model from Ostfeld and Tubaltzev(2008) was verified by applying 2-Looped, Hanoi and Ostfeld's networks. And sensitivity analysis about ant number, number of ants in a best group and pheromone decrease rate was accomplished. After the verification, it was applied to real water network from S water treatment plant. As a result of the analysis, in the Two-looped network, the best design cost was found to $419,000 and in the Hanoi network, the best design cost was calculated to $6,164,384, and in the Ostfeld's network, the best design cost was found to $3,525,096. These are almost equal or better result compared with previous researches. Last, the cost of optimal design for real network, was found for 66 billion dollar that is 8.8 % lower than before. In addition, optimal diameter for aged pipes was found in this study and the 5 of 8 aged pipes were changed the diameter. Through this result, pipe construction cost reduction was found to 11 percent lower than before. And to conclusion, The least cost design model on water distribution system was developed and verified successfully in this study and it will be very useful not only optimal pipe change plan but optimization plan for whole water distribution system.

• 한국물환경학회지
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• 제22권3호
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• pp.492-497
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• 2006

Feasibility of simultaneous removal of organic materials and nitrogen in the wastewater from fisheries processing plant was evaluated using entrapped mixed microbial cell (EMMC) process. The experiment was performed using activated sludge from municipal sewage treatment plant which was immobilized with gel matrix by cellulose triacetate. It was found the stable operation at the treatment system which is composed of anoxic and oxic tank, was possible when the organic and nitrogen loading rates were increased stepwise. The organic and nitrogen loading rates were conducted from 0.65 to $1.72kgCOD/m^3/d$ and from 0.119 to $0.317kg\;T-N/m^3/d$ with four steps, respectively. The maximum nitrogen loading rate which could satisfy the regulated effluent standard of nitrogen concentration, was $0.3kg\;T-N/m^3/d$. The removal efficiency of total nitrogen was decreased apparently as increasing nitrogen loading rates, whereas the removal efficiency of ammonium nitrogen was effective at the all tested nitrogen loading rates. Therefore, it was concluded that nitrification was efficient at the system. Nitrate was removed efficiently at the anoxic tank. whereas the nitrification efficiency at the oxic tank ranged 94.0% to 96.9% at the tested loading rates. The removal efficiencies of chemical oxygen demand (COD) and those of total nitrogen at the entire system ranged from 94.2% to 96.6% and 73.4% to 83.4%, respectively.

• 한국습지학회지
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• 제23권1호
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• pp.7-13
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• 2021

급속한 산업발전과 인구증가, 생활 수준의 향상으로 영양염류를 포함한 하·폐수 발생량이 매년 증가하고 있다. 증가하는 하·폐수 발생량과 더불어 미처리 연계처리수(분뇨, 가축분뇨, 산업폐수, 침출수, 음폐수)또한 발생량이 증가하고 있고, 연계처리수 상당 수가 인근 하수처리장으로 연계하여 연계처리되고 있다. 연계처리수는 기존 유입하수와 비교했을 때 저유량 고농도의 특징을 가지고 있기때문에 하수처리장에서는 방류수 수질 악화, 처리량 증가, 오염부하 증가, 충격부하 또는 중금속 유입 등과 같은 많은 문제점을 가지게 된다. 이와같은 문제를 해결하기 위해서 하수처리장에 연계 유입되는 연계처리수의 양 및 수질 등의 조사가 필요하고, 하수처리에 미치는 영향등에 관한 연구가 필요하다. 따라서 본 논문은 연계처리수의 영향을 살펴보기 위해 4계절에 따른 수온조건을 고려했을 때 연계처리수의 영향 및 연계처리수 유입 유량 분배 등 영향인자를 고려하여 시나리오를 만들고 최적의 효율을 나타내는 조건을 분석하고자 한다.

• 멤브레인
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• 제32권6호
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• pp.390-400
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• 2022

나노여과막(NF)은 식품가공, 제약 등 폐수는 물론 지자체 하수처리시설에서 배출되는 폐수 처리에 있어 훨씬 낮은 압력으로 운용이 가능해 역삼투막(RO)보다 인기가 높다. NF막의 경우 분리 메커니즘은 투과확산 기작과 더불어 RO 박막보다 낮은 가교밀도로 인한 체거름 메커니즘이다. 막 오염은 세라믹 막과 달리 고분자 막의 경우 나노 여과 공정의 고질적인 문제 중 하나이다. 이러한 문제를 해결하기 위해 차아염소산나트륨을 사용한 멤브레인 세척이 이루어진다. 폴리머 멤브레인에 비해 세라믹 멤브레인은 이러한 화합물에 매우 안정적이다. 본 리뷰에서는 NF 프로세스에 의한 폐수 처리의 다양한 유형의 세라믹 막 적용에 대해 논의한다.

• Animal cells and systems
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• 제12권1호
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• pp.41-46
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• 2008

A bacterium strain called Bacillus coagulans was isolated from an industrial wastewater drainage and selected for its antimicrobial activities against bacteria and fungi. Characterization studies strongly suggested that this strain is Bacillus coagulans. Antimicrobial activity was found against gram-positive, gram-negative bacteria and yeast strain. Maximal activity was observed after 24 h when incubated at $30^{\circ}C$ and pH 8. The activity was found to be stable at $75^{\circ}C$ for 30 min and at pH range of 2-12. Analysis of the antimicrobial compound by SDS-PAGE suggested a molecular mass of approximately 7.5 KDa. The substance was characterized as a bacteriocin, because of its proteinaceous nature and low molecular weight. Our bacteriocin could potentially be used as a food preservative, because of its thermostable property and broad antimicrobial spectrum.

• 한국식품위생안전성학회지
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• 제9권4호
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• pp.185-189
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• 1994

This study was to investigate time-dependent degradation process under various pH condition for organophosphorus(org-p) insecticides, namely Demeton-s-methyl, diazinon, Parathion, Phenthoate, and EPN in several waters. They were analysed by GC-FTD according to standard methods for the examination of water and wastewater. In pH=4, diazinon showed disappearance after 14 days in chromatogram. In pH=11, org-p insecticides were almost degradable after 7 days. In this condition, effect of pH on degradation process was greater than of light. In pH=7, org-p insecticides persisted residues after 112 days except Demeton-s-methyl. In BOD5 120, 250 ppm and domestic water, org-p insecticides showed also rapid degradation process.

• 상하수도학회지
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• 제20권3호
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• pp.397-402
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• 2006

The treatment characteristics of leachate produced from pretreatment facilities like composting and feeding were investigated in a mesophilic anaerobic treatment. Experiments were performed in two phase which were acidification and methane fermentation. The acidification step was optimized for OLR from 1 to $4.5kg\;COD/kg\;VS{\cdot}day$ without adding NaOH. As experiment dates became longer, the solubilization ratio of particles increased up to 30% over 70 days. TVA was generated up to maximum 9,970mg HAc/L at OLR of $2kg\;COD/kg\;VS{\cdot}day$. But TVA was generated to minimum 6,519mg HAc/L at OLR of $4.5kg\;COD/kg\;VS{\cdot}day$. The acidification ratio was analyzed from 10.9% to 3.8% at OLR of $2kg\;COD/kg\;VS{\cdot}day$ and $4.5kg\;COD/kg\;VS{\cdot}day$ respectively. After 55 days, salt contents in the acid fermenter were accumulated and stabilized at the concentration of 3,150mg/L. Sodium ion($Na^+$) concentration was stabilized at 1,300mg/L. At methane fermentation step, biogas was generated up to 750ml and 937.5ml at the feeding volume of 20ml and 25ml respectively for acid fermented liquid during 25 days. About 80% of total biogas was generated during early 15 days and 95% were generated during 18 days respectively. After 25 days of the BMP test, acetic acid was removed approximately 97% and 98%, in case of those two experimental conditions.

• 상하수도학회지
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• 제22권5호
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• pp.561-569
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• 2008

We analyzed contents of cations and anions for the domestic bottled drinking water. Results showed that total cation content was 45.81 mg/L and contained 40% of Ca. The content of cations were decreased in the order of Ca>Si>Na>Mg>K. Total anion content was 12.20 mg/L and contained 90% of ${SO_4}^{2-}$ and $Cl^-$. $F^-$ and $NO_{3-}N$ were a little contained. While Si content was reduced 2.3~75.7%(mean value:38.5%) after freezing, Ca content was reduced 45.2% after boiling. It showed that water containing higher Ca content was significantly decreased after boiling. Precipitates formed by freezing and boiling is composed of minerals such as Si and Ca. Compared to minerals from food intake, concentrations of minerals from water intake are expected to be less influenced. It is recommended Bottled Water that contains more than 20 mg/L of Ca(exceeding water-quality standard for turbidity) is safe to drink without thawing and boiling.