• 상하수도학회지
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• 제33권6호
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• pp.413-420
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• 2019

Pretreatment system of desalination process using seawater reverse osmosis(SWRO) membrane is the most critical step in order to prevent membrane fouling. One of the methods is coagulation-UF membrane process. Coagulation-UF membrane systems have been shown to be very efficient in removing turbidity and non-soluble and colloidal organics contained in the source water for SWRO pretreatment. Ferric salt coagulants are commonly applied in coagulation-UF process for pretreatment of SWRO process. But aluminum salts have not been applied in coagulation-UF pretreatment of SWRO process due to the SWRO membrane fouling by residual aluminum. This study was carried out to see the effect of residual matal salt on SWRO membrane followed by coagulation-UF pretreatment process. Experimental results showed that increased residual aluminum salts by coagulation-UF pretreatment process by using alum lead to the decreased SWRO membrane salt rejection and flux. As the salt rejection and flux of SWRO membrane decreased, the concentration of silica and residual aluminum decreased. However, when adjusting coagulation pH for coagulation-UF pretreatment process, the residual aluminum salt concentration was decreased and SWRO membrane flux was increased.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.122-123
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• 2021

This study examines the performance of pretreatment process system as the initial construction stage of the pretreatment process system to use CGS, a by-product generated in IGCC, as a concrete fine aggregate of construction materials. The process undergoes a grinding process capable of grinding to a predetermined particle size during primary grinding and a sorting plant through sieve grading of 2.5 mm or less for particle size correction. Afterwards, it is hoped that the use of coal gasification slag of Korean IGCC as a fine aggregate for concrete will be distributed and expanded by producing quality-improved CGS fine aggregate using water as a medium for removing impurities and particulates.

• Korean Chemical Engineering Research
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• 제56권4호
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• pp.441-446
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• 2018

초본계 바이오매스는 목본계 바이오매스에 비해 구조가 견고하지 않아 화학적 전환이 용이하다. 하지만 당질계 바이오매스에 비해 리그닌이 많아 전처리가 필수적으로 요구된다. 오르가노솔브는 리그닌과 같은 효소당화에 저해가 되는 물질을 분별하기 쉬우며 특히 에탄올과 같은 낮은 분자량의 용매는 증류를 통해 재사용이 용이하다는 장점이 있다. 한편 침출식 전처리 공정은 기존의 회분식 공정에서 문제점으로 언급되었던 분별된 성분들의 재결합 현상을 방지할 수 있고 고-액 분리가 용이하다는 장점이 있으며, 향후 스케일업에도 유리하다. 아직까지는 바이오알코올 생산 공정 중 전처리 과정에서 소모되는 에너지 비용이 크기 때문에 본 연구의 전처리에서는 촉매 없이 에탄올만을 이용해 부가공정의 발생을 줄이려고 했다. 침출식 전처리는 $150{\sim}190^{\circ}C$에서 30~99.5 wt% 에탄올을 이용하여 20~60분 동안 수행되었다. 높은 반응온도와 긴 반응시간은 에너지 소모가 크기 때문에 물리적 전처리 방법과의 연계를 적용하여 에너지 저감의 가능성을 알아보았다.

• 한국건설순환자원학회논문집
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• 제10권3호
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• pp.285-292
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• 2022

본 연구에서는 IGCC에서 발생되는 CGS를 각각의 전처리 공정마다 콘크리트 잔골재 품질 평가를 수행하였다. 전처리 공정 시스템은 순환 잔골재 생산설비를 기반으로 구축되었다. 각각의 전처리 공정 시스템에 따른 측정값을 반복측정 분산분석을 통해 전처리 공정의 통계적 유의성을 분석하였다. 분석결과 전처리 공정 시스템 전·후의 CGS 잔골재 품질의 경우 밀도는 5.2 % 상승, 흡수율은 1.86 % 감소, 0.08 mm체 통과량은 2.25 % 감소, 조립률 및 입도분포 또한 입도 조정이 가능한 것으로 나타났다. 결국, 전처리 공정 시스템은 CGS의 불순물을 제거하고 입도를 개선시켜 물리적 성질 및 입자특성이 향상됨을 확인할 수 있으며, 잔골재로서의 활용하기 위한 CGS의 품질을 KS F 2527에서 규정하고 품질기준 범위 이내로 개선할 수 있는 것으로 나타났다.

• 상하수도학회지
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• 제7권1호
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• pp.20-28
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• 1993

The Wastewater from the weight reduction process of polyester is more difficult to be treated biologically than the general wastewater from dyeing and finishing processes in textile industries. Above wastewater shows high pH, high organic strength and wide variation of organic loading. These characteristics are due to TPA and EG resulting from alkaline weight-reduction process and make trouble in the operation of activated sludge process. Therefore, the objective of this study is to develop the pretreatment method for the successful operation of treatment process. For the successful pretreatment process, the wastewater from weight-reduction process should be segregated from other wastewater stream and then acidified with concentrated sulfuric acid to precipitate out TPA from DST solution. At the optimum pH of 2. 2, the initial $COD_{cr}$ 60,000mg/l is reduced to 11,500mg/l and the removal efficiency of $COD_{cr}$ is 81.1%. The required amount of sulfuric acid for pretreatment is not greater than the amount for the the existing neutralization process. Moreover, the supernatant of pretreatment process can be reused in acidification of wastewater.

• Carbon letters
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• 제17권1호
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• pp.1-10
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• 2016

Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.

• 상하수도학회지
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• 제27권5호
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• pp.555-560
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• 2013

A cost analysis method for pretreament processes of a large scale seawater desalination plant was considered using a cost estimation model, WaTER (Water Treatment Estimation Routine). This model is based on cost functions of U.S. EPA to conduct economic analysis of water treatment facilities. A virtual seawater desalination plant which has pretreatment production capacity of $100,000m^3$ per day was chosen as a model plant. Dual media filtration and microfiltration systems were compared as pretreatment process, and the following reverse osmosis process was modeled. As a result, microfiltration showed a price competitiveness in condition of operating with reverse osmosis process by reducing the loads of water treatment and membrane cleaning despite it's high annual cost.

• 자원리싸이클링
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• 제33권2호
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• pp.24-36
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• 2024

리튬이온전지 재활용 공정은 직접 재활용, 습식제련공정, 건식제련공정으로 분류되어 왔으며, 습식제련공정 기반 상용공정은 해체, 파분쇄, 열처리, 선별 등으로 구성된 전처리 공정으로 블랙매스를 생산하고 습식제련공정으로 각 금속을 회수한다. 개발 중인 모든 리튬이온전지 재활용공정은 전구체 원료 제조를 위해 전처리공정 후 침출 등의 습식제련공정을 진행하기 때문에 이 글에서는 재활용공정의 전처리공정에 따른 분류법을 제시하였다. 현재 개발 중인 주요 공정은 황산염배소, 탄소열환원, 합금제조 등이며, 전처리공정에서 미이용 부산물의 활용이 가능할 경우 리튬이온전지 재활용 공정의 경제성 향상이 가능하리라 판단된다.

• 상하수도학회지
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• 제22권4호
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• pp.449-454
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• 2008

Some pretreatment methods have been proposed to enhance the biodegradability and to shorten the hydrolysis reaction time. By means of efficient pretreatment the suspended solids (SS) can be made of better accessible for the anaerobic bacteria. There are several ways how this can be accomplished, which include biological, mechanical, thermal, and chemical methods. For the sludge solubilization using the cavitation phenomenon, we have tried to develop a pretreatment process consisted of a reactor and pumps. The objectives of this study were to develop a advanced wastewater treatment consisted of IABR and the cavitation with PGA. The most effective removal for organic matter and nutrients were occured when both cavitation pretreatment and ${\gamma}$-PGA were applied at the IABR process. Only small portion of ${\gamma}$-PGA at a rate of 1.38mg/L, was enough to improve sedimentation ability, SS removal efficiencies, and sludge volume reduction. After the sludge solubilization by the cavitation, SCOD increased to 193% and SS decreased to 36%. The removal ratio of BOD was 94.5%, T-N removal ratio was 85.5% and T-P removal ratio was 84.9%. The combination process of the IABR with the cavitation and PGA addition seems to be very effective alternative wastewater treatment process.

• 상하수도학회지
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• 제20권2호
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• pp.235-244
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• 2006

A PCF(Pore Controllable Fiber Filter) process was applied as a pretreatment of water treatment for reduction of turbidity. The experimental results obtained from the PCF showed that the removal efficiency of turbidity without coagulation was around over 70 percent. However, the removal efficiency of turbidity by the coagulation-PCF process was high as much as over 95%. Thus, the coagulation pretreatment was required for the better operation of the PCF. The SEM (Scanning Electron Microscope) images of fiber before and after filtration showed that the filtration mechanism of PCF filter is both controlling attachment mechanism and Sieving mechanism through fiber pore. For the coagulation-PCF process, optimum dosage of coagulant was needed for the economical operation, and for this, determining the optimum dosage by using a filter column test. Also only 16mg/L of alum was used to obtain high algae removal efficiency over 90%. Therefore, it can be concluded that coagulation-PCF process is very effective pretreatment process for algae removal.