• 한국수산과학회지
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• 제33권3호
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• pp.205-212
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• 2000

공기 구동식, 고속 폭기식 및 벤튜리식 포말분리 장치를 동일한 용량으로 제작하여 양어장 순환수 중의 단백질,총 부유 고형물 및 탁도를 제거하는데 있어 각 포말 분리장치의 운전 특성을 알아보고자 하였다. 공기구동식 포말분리기의 유략감소가 거의 없었으나 벤튜리식 포말분리기는 $66.1{\%}$정도의 유량감소가 발생하였으며 고속 폭기식 포말분리기는 $77.2{\%}$의 유량감소가 발생하였다. 공기 구동식, 고속 폭기식 및 벤튜리식 포말분리 장치의 단백질 제거속도는 수력학적 체류시간이 증가함에 따라 지수적으로 감소 하였다. 0.32 분 이상의 수력학적 체류시간에서는 공기 구동식 포말분리장치의 제거속도와 제거율이 가장 높게 나타났으며 그 이하의 수력학적 체류시간에 대해서는 고속 폭기식 포말분리 장치의 제거속도와 제거율이 가장 높은 것으로 나타났다. 수력학적 체류시간의 변화에 따른 총 부유 고형물과 탁도의 제거속도와 제거율의 변화는 단백질 제거속도 및 제거율의 변화와 거의 비슷하였으며 벤튜리식 포말분리기는 짧은 수력학적 체류시간에서는 총 부유고형물의 제거 효율이 다른 두 포말분리기에 비해 떨어지는 것으로 나타났다. 탁도의 제거는 공기 구동식 포말 분리기가 가장 우수한 것으로 나타났다.

• 공업화학
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• 제5권5호
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• pp.899-903
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• 1994

게껍질로부터 Hackman법으로 키틴을 추출하였고 키토산은 이것을 일정 온도($100^{\circ}C$)에서 NaOH 용액의 농도와 반응 시간을 변화시켜 각각의 탈아세틸화 정도에 따라 제조하였다. 제조한 시료들은 A=19%, B=52%, C=70% 그리고 D=93%의 탈아세틸화된 것을 사용해 여러 가지 시험을 하였다. 분자량은 탈아세틸화도가 증가함에 따라 감소되는 현상을 나타냈고, 폐수처리 효과에 있어서 SS 제거율은 탈아세틸화도가 증가함에 따라 증가하였고 pH 9에서 우수한 성능을 나타냈으며, COD 제거율은 중성 영역에서 가장 좋게 나타났다.

• 상하수도학회지
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• 제24권3호
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• pp.267-276
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• 2010

Many plants have been improved to adapt the target of the biological treatment processes changed from organics to nutrients since the water quality criteria of effluent was reinforced and included T-N and T-P for the municipal wastewater treatment plant. To meet the criteria of T-N and T-P, the conventional biological reactor such as aeration tank in activated sludge system is changed to the BNR (biological nutrient removal) processes, which are typically divided into three units as anaerobic, anoxic and oxic tank. Therefore, the solid separation process should be redesigned to fit the BNR processes in case of the application of the DAF (dissolved air flotation) process as an alternatives because the solid-liquid separation characteristics of microbial flocs produced in the BNR processes are also different from that of activated sludge system as well. The results of this study revealed that the microbial floc of the anaerobic tank was the hardest to be separated among the three steps of the unit tanks for the BNR processes. On the contrary, the oxic tank was best for the removal efficiency of nutrients as well as suspended solid. In addition, the removal efficiency of nutrients was much improved under the chemical coagulation treatment though coagulation was not indispensable with a respect to the solid separation. On the other hand, in spited that the separation time for the microbial floc from the BNR processes were similar to the typical particles like clay flocs, over $2.32{\times}10^3$ ppm of air volume concentration was required to keep back the break-up of the bubble-floc agglomerates.

• Environmental Engineering Research
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• 제19권4호
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• pp.395-399
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• 2014

Operation characteristics of the sequencing batch reactor (SBR) process with electro-flotation (EF) as a solid liquid separation method (EF-SBR) were investigated. EF-SBR process showed excellent solid-liquid separation performance which enabled to separate biosolids from liquid phase within 30 min and to extend cyclic reaction time. Although influent organic loading rate was increased stepwise from 5 to 15 g COD/day, food to microorganisms (F/M) ratio could be maintained about 0.3 g COD/g VSS/day in EF-SBR because biomass concentration could be easily controlled at desired level by EF. However, it was impossible to increase biomass concentration at the same level in control SBR (C-SBR) process because solid-liquid separation by gravity settling showed a limitation at higher mixed liquor suspended solids (MLSS) concentration with 60 min of settling time. Total chemical oxygen demand (TCOD) removal efficiency of EF-SBR process was not decreased although influent organic loading rate became 3 times higher than initial value. However, it was seriously deteriorated in C-SBR process after increasing the rate over 10 g COD/day, which was accounted for insufficient organic removal by relatively higher food to microorganisms (F/M) ratio as well as biosolids wash-out by a limitation of gravity sedimentation.

• Membrane and Water Treatment
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• 제14권1호
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• pp.27-33
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• 2023

In previous studies, solely ferric (Fe³⁺) and calcium (Ca²⁺) ions were commonly used for removal of PO₄-P (considered as T-P in this study) in wastewater via chemical precipitation. Herein, the removal of total phosphorus (T-P) in wastewater was performed using various mineral and lime dissolved solutions. The dissolution kinetics of different minerals (feldspar, olivine, elvan, illite, sericite, and zeolite) and lime was compared and used their solutions for T-P removal of real wastewater. The highest T-P removal (almost 90%) was obtained by the lime dissolved solution and followed by zeolite, illite, feldspar, and others. We observed a significant co-relationship (R of 0.96) between the amount of initial Ca²⁺ and T-P removal. This was induced by formation of hydroxyapatite-like mineral via Ca-P precipitation reaction at high pH solution. Furthermore, additional removal of suspended solid (SS) and chemical oxygen demand (COD) was achieved by only lime dissolved solution. Finally, the lime-feldspar dissolved solutions were prepared at different ratios (10-50%), which showed a successive T-P removal up to two times by samples of 40 and 50%.

• 한국수산과학회지
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• 제32권5호
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• pp.649-653
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• 1999

자성 미분체와 부유 고형물사이에 작용하는 응집력에 의해 부유 고형물의 표면에 다수의 자성 미분체가 부착된 형태의 자성 플럭을 형성하고 이들을 자력 분리하는 방식의 자성 유체분리 기술이 양어장 순환수내 부유 고형물의 제거에 적용 가능함을 확인하였다. 자성 유체분리에 의한 순환수내 부유 고형물의 제거에 있어서 조업변수인 자석의 세기, 공탑 액체유속, 마그네타이트/부유 고형물의 질량비, 그리고 부유 고형물의 농도의 영향 평가에서는, 1. 자성 유체분리에 의한 부유 고형물의 제거에서는 사용하는 자석의 세기가 부유 고형물의 제거효율은 물론 설비의 처리 용량을 결정하는데 지배적임을 확인하였으며, 2. 공탑 액체유속의 증가, 즉 유체력의 상승에 따른 제거효율의 저하는 마그네타이트/부유 고형물의 질량비가 증가, 즉 자성 플럭자체의 자화력이 보다 강하게 작용하면서 감소하였다. 본 실험조건에서는 공탑 액체유속과 자성 미분체의 투입량, 그리고 처리수내 부유 고형물의 농도 등을 고려시 마그네타이트/부유 고형물의 적정 질량비는 약 1.0 임을 알 수 있었다.

• KSBB Journal
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• 제22권3호
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• pp.129-133
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• 2007

This study represents that a removal efficiency of organic matters in wastewater is activated by a sludge process using new mixed microbial population. In case of mixed microorganisms, removal rates of suspended solid (SS), biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were over 90 percent under experimental condition, and removal efficiency of organic matters, sludge density index (SDI) and capillary suction time (CST) in mixed population were higher than that in not-mixed microorganism, while total kjeldahl nitrogen (TKN) and total phosphorus (T-P) which indicate a degree of eutrophication were removed easily in both case. From these results, we may propose that an application of the mixed microbial population is useful to treat domestic wastewater including a great deal of organic matters.

• 한국환경과학회지
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• 제19권11호
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• pp.1315-1322
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• 2010

A membrane bioreactor (MBR) was designed using polyvinylidene fluoride(PVDF)-type hollow fiber membrane modules with a treatment capacity of 10 ton/day. A pilot plant was installed in a sewage treatment plant and was operated with an intermittent aeration method which avoids any concentration gradient of suspended solids (SS) in the MBR. For continuous operation, the pilot plant was first tested with influent (mixed liquor suspended solid:MLSS of 1000-2000 mg/L) of aeration tanks in the sewage treatment plant. The MBR was pre-treated with washing water, 10% ethanol solution, 5% NaOCl solution and finally washing water, one after another. To demonstrate the effect of the MBR on sewage treatment, compared with conventional activated sludge processes, we investigated the relationships among permeate amount (LMH), change in operation conditions, influent MLSS level and sludge production. It was found that the optimum aeration rate and suction pressure were $0.3\;m^3$/min and 30~31 cmHg, respectively. Under stable conditions in aeration, suction pressure, influent flow rate and drainage, the SS removal efficiency was more than 99.99% even when the MLSS loading rate changes. Compared with conventional activated sludge processes, the MBR was more effective in cost reduction by 27% based on permeate amount and by 51.5% on sludge production.

• 한국수산과학회지
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• 제37권3호
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• pp.179-185
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• 2004

The characteristics of foam generation were assessed for freshwater and seawater using a foam generator. Both in freshwater and seawater, the height of the foam layer increased with initial protein concentrations. The height of the foam layer also increased with pore size of the air distributor. The optimum superficial air velocities (SAV) in freshwater and seawater were 0.84 cm/sec and 0.6 cm/sec, respectively. The height of the foam layer was the highest in pH 3 in freshwater and in the region of pH 5-7 in seawater. The height of the foam layer increased with $NaHCO_3$ concentration in freshwater, and $NaHCO_3$ concentration had little effect in seawater. Removal efficiencies of total suspended solid (TSS) and turbidity decreased with an increase of initial protein concentrations in a batch foam separator both in freshwater and seawater.

• 상하수도학회지
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• 제10권4호
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• pp.45-54
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• 1996

Effects of temperature on the efficiency of the Upflow Anaerobic Sludge Blanket(UASB) process for treatment of wastewater from a starch and related products manufacturing industry were investigated using laboratory scale reactors equipped with two types of Gas-Solid Separator(GSS). Both fresh digested sludge and granular sludge stored nearly for one year at room temperature were good as a seeding material. The reactors seeded with aged granular sludge showed slow start-up, however, lowered activity at the initial period was recovered gradually. The GSS with an inner cylinder was proved to be effective in liquid-solid separation compared to the conventional type. Although the rate of organic removal and gas production per unit volatile suspended solids in the reactor reduced significantly as the temperature varied from 35 to $20^{\circ}C$, possibility of operation at low temperatures was shown as a result of gradual buildup of volatile suspended solids in the bed. Stable operation with a reduced efficiency was possible at a COD loading of $5-8kg/m^3/day$ at a temperature as low as $20^{\circ}C$.