• 한국물환경학회지
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• 제22권5호
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• 한국환경보건학회지
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• 제23권2호
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• pp.24-27
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• 1997

This study has been designed to check the removal effect of contaminated water by various water treatmemt processes using sediment filter, activated carbon, reverse osmosis membrane, ultra vilolet sterilizer and ultra filtration and then to analyze the change of pH, the concentration of chlorides, bacteria and E. coli. after 24 hours. pH has increased as much as 0.15-0.32 by activated carbon but decreased sharply by reverse osmosis treatment after 24 hours. The removal effect of chloride was low by activated carbon and ultra filter but high in reverse osmosis. The removal effect of bacteria and E. coli was low by activated carbon and membrane filter system using activated carbon. Ultra filtration process was effective for purify agricultural water containg bacteria and E.coli.

• 환경위생공학
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• 제12권2호
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• pp.65-74
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• 1997

The purpose of this study was to investigate the removal effect and variation of contaminated water by various water treatment processes using sediment filter, activated carbon, photocatalysis, reverse osmosis, ultra violet sterilizer and ultra filtration. The removal effect of chloride and trace metal was low by activated carbon and ultra filter but high in reverse osmosis. The removal effect of bacteria and E. coli was low by activated carbon and membrane filter system using activated carbon but high in impregnated activated carbon. The removal effect of TCE was low in sand and ultra filter system as compared with activated carbon. Ultra filtration process was effective for purify agricultural water without E.coli. Reverse osmosis was effective to remove heavy metal and activated carbon was effective to remove halogenated organic chemical compound. The flux and the removal effect of COD in spiral wound ultrafilter were higher than the hollow fiber ultrafilter.

• 상하수도학회지
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• 제11권1호
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• pp.42-52
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• 1997

The affection of activated carbon on the dissolved aluminum ion in drinking water has been observed. In addition, the aluminum ion removal capability of activated, alumina, chitosan, and ion exchange resin have been investigated. Experimental results indicated that the coal based activated carbon released considerable amount of aluminum ion to the water while coconut shell based activated carbon didn't. However the release was not continuous. Activated alumina didn't show any recognizable removal capability for aluminum ion in water. Particulate chitosan has removed aluminum ion although dissolved chitosan has not. However it need to development a regeneration process for chitosan to be an effective mean for aluminum ion removal. Ion exchange resin showed a reliable aluminum ion removal capability. The ion exchange capacity was 2.63 meq/g resin for the aluminum ion in drinking water.

• 상하수도학회지
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• 제19권6호
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• pp.781-790
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. Many of the problems occurring in the GAC process are associated with the operation goal and performance. The purpose of this study were to evaluate the design, operation, and performance of granular activated carbon process in D water treatment plant. The optimal operation conditions of GAC process such as backwashing condition, granular activated carbon replacement time were discussed. The design, operation and performance of GAC process is influenced by their raw water characteristics and placement within the treatment process sequence. A critical analysis of plants experience and the information from the literature identifies the effectiveness of GAC process and indicates where modifications in design and operation could lead to improved performance. It would be useful to evaluate and optimize the GAC process in other treatment plant.

• 한국물환경학회지
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• 제16권4호
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• pp.513-521
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• 2000

Intermittently aerated activated sludge process was applied as a water reuse process of $70m^3/day$ for the upgrade of organic, nitrogen and phosphorus removal efficiency and clarifier performance. After application of the intermittently aeration, removal efficiency of BOD, SS, T-N and T-P were achieved 95%, 90%, 80% and 60%, respectively. Removal efficiencies in intermittently aerated process were considerably increased. comparing to those of continuously aerated activated sludge process. Also sludge rising problem in clarifier was improved. Average concentration of supplied reusing water were BOD 5 mg/L, turbidity 4 NTU and after chlorination, residual chlorine 0.4 mg/L, coliform 0 MPN/100mL. Intermittently aerated activated sludge process could be one of the best alternative process for the retrofit of conventional activated sludge process for the removal of nutrient in water reuse system.

• Membrane and Water Treatment
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• 제9권5호
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• pp.293-300
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• 2018

The removal of volatile organic compounds (VOCs) from water using KOH-activated pine tree needle leaves biochar is considered a cost effective and efficient process. In this study, pine tree needle leaves were mixed with 0, 50, 100 and 200% (KOH weight/feedstock weight) of KOH, respectively. Then, the mixture was pyrolyzed at $500^{\circ}C$ for 6 hrs. The adsorption characteristics of 10 VOCs to the biochar were tested. The results indicated that the removal efficiency of the KOH activated biochar was highest in 100% KOH-biochar. The VOC removal efficiencies of 50% and 200% KOH activated biochar were similar and the 0% KOH activated biochar showed the lowest VOC removal. The FTIR results showed that increasing the amount of KOH seemed to enhance the formation of various functional groups, such as -OH, -C=C, -O. The adsorption strength of 10 VOCs to the KOH activated biochar seemed to be increasing by the increase of the solubility of VOCs. This may suggest that the adsorption is taking place in hydrophilic sites of the biochar surface. The KOH activated pine tree needle leaves biochar can be an effective sorbent for VOCs removal in water and 100% KOH mixing seemed to provide better sorption capacity.

• 상하수도학회지
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• 제20권5호
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• pp.719-726
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• 2006

Adsorption isotherms and kinetics for taste and odor (T&O) compounds and natural organic matters (NOMs) were performed to evaluate the impacts of activated carbon particle size on coagulation and adsorption. Adsorption capacities for iodine, T&O compounds, and NOM of all the activated carbons under #325 mesh were more excellent than those of virgin activated carbons. Small activated carbon particles were more rapidly adsorbed low molecular weight T&O compounds in the water, while those were slowly adsorbed high molecular weight NOM. When the activated carbon and alum were added simultaneously, the adsorption capacity for organics was better than alum was added alone.

• 공업화학
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• 제27권1호
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• pp.62-67
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• 2016

본 연구에서는 정수슬러지를 원료로 사용하여 펠렛형 흡착제를 제조하고 질소흡착법, XRD, XRF 및 암모니아 승온탈착법 등을 사용하여 물리 화학적 특성을 분석하였다. 정수슬러지 유래 펠렛형 흡착제와 첨착활성탄의 암모니아 및 포름알데히드 기체의 흡착 성능을 비교하였다. 정수슬러지로부터 제조된 펠렛형 흡착제는 첨착활성탄보다 표면적과 기공부피는 훨씬 작지만 암모니아를 훨씬 더 많이 흡착할 수 있었다. 이는 정수슬러지로부터 제조된 펠렛형 흡착제 표면에 산점이 훨씬 더 많이 분포해 있어서 화학흡착에 의해 암모니아를 흡착하기 때문이다. 반면에, 산성가스인 포름알데히드 가스 흡착의 경우는 넓은 표면적과 발달된 기공으로 인하여 첨착활성탄의 흡착성능이 정수슬러지로부터 제조된 펠렛형 흡착제에 비해 훨씬 우수하였다.

• 대한환경공학회지
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• 제30권9호
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• pp.925-932
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• 2008

입상활성탄 재질별 신탄 및 사용탄에서의 tetracycline계 항생물질 4종에 대한 파과특성의 경우 석탄계 활성탄이 가장 늦게 파과에 도달하였으며, 다음으로 야자계, 목탄계 순으로 조사되었다. 또한, 물질별 활성탄에서의 파과특성을 살펴보면 tetracycline(TC)의 파과시점이 가장 늦은 것으로 나타났으며, 다음으로 oxytetracycline(OTC), chlortetracycline(CTC), minocycline(MNC)으로 나타났다. 활성탄 g당 tetracycline계 항생물질 4종에 대한 최대 흡착량(X/M)은 석탄계 활성탄이 가장 높은 것으로 나타났으며, 다음으로 야자계와 목탄계 순으로 나타났다. tetracycline계 항생물질 4종에 대한 석탄계 활성탄의 최대 흡착량(X/M)은 야자계와 목탄계 활성탄에 비해 각각 1.27$\sim$1.36배 및 1.69$\sim$1.84배 정도 높은 것으로 조사되었다. 활성탄 사용율(carbon usage rate, CUR)은 tetracycline의 경우 석탄계 재질의 활성탄이 2.96 g/일, 야자계나 목탄계 활성탄은 각각 3.40 g/day 및 4.53 g/day의 활성탄을 사용하여야만 제어가 가능한 것으로 조사되어 석탄계 활성탄이 다른 재질의 활성탄들에 비해 적은 양으로도 tetracycline계 항생물질을 제어할 수 있는 것으로 나타났으며, 나머지 tetracycline계 항생물질 3종에서도 이와 유사한 결과를 나타내었다. 또한, 석탄계 활성탄 신탄과 사용탄에 대한 CUR을 비교해보면 tetracycline의 경우 신탄을 사용하였을 경우 보다 1.3년 사용탄 및 3.1년 사용탄을 사용하였을 경우가 CUR이 1.96배 및 2.53배 정도 높은 것으로 나타났다.