• Title/Summary/Keyword: Particulate removal

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Removal of Nitrate and Particulate from Groundwater with Two stage Biofilter system (2단 생물막여과 탈질시스템에서 지하수의 질산성질소 및 입자제거특성)

  • Lee, Moo-Jae;Park, Sang-Min;Jun, Hang-Bae;Kim, Kong-Soo;Lim, Jeoung-Su
    • Journal of Korean Society on Water Environment
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    • v.21 no.6
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    • pp.669-675
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    • 2005
  • Biological nitrate removal from groundwater was investigated in the biofilters packed with both gravel/sand and plastic media. Removal of particles and turbidity were also investigated in the 2-stage biofilter system consisted of biofilter and subsequent sand filter. In the single biofilter packed with gravel and sand, nitrate removal efficiency was dropped with the increase of filtration velocity and furthermore, nitrite concentration increased up to 3.2 mg-N/L at 60 m/day. Denitrification rate at the bottom layer below 25 cm was faster 8 times than upper layer in the up-flow biofilter. Nitrite build-up, due to the deficiency of organic electron donors, occurred at the upper layer of bed. Besides DO concentration and organic carbon, contact time in media was the main factor for nitrate removal in a biofilter. The most of the effluent particles from biofilter was in the range from 0.5 to $2.0{\mu}m$, which resulted in high turbidity of 1.8 NTU. However, sand filter followed by biofilter efficiently performed the removal of particles and turbidity, which could reduce the turbidity of final filtrate below 0.5 NTU. Influent nitrate was removed completely in the 2-stage biofilter and no nitrite was detected.

Experimental investigation of aerosols removal efficiency through self-priming venturi scrubber

  • Ali, Suhail;Waheed, Khalid;Qureshi, Kamran;Irfan, Naseem;Ahmed, Masroor;Siddique, Waseem;Farooq, Amjad
    • Nuclear Engineering and Technology
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    • v.52 no.10
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    • pp.2230-2237
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    • 2020
  • Self-priming venturi scrubber is one of the most effective devices used to collect aerosols and soluble gas pollutants from gaseous stream during severe accident in a nuclear power plant. The present study focuses on investigation of dust particle removal efficiency of the venturi scrubber both experimentally and theoretically. Venturi scrubber captures the dust particles in tiny water droplets flowing into it. Inertial impaction is the main mechanism of particles collection in venturi scrubber. The water injected into venturi throat is in the form of jets through multiple holes present at venturi throat. In this study, aerosols removal efficiency of self-priming venturi scrubber was experimentally measured for different operating conditions. Alumina (Al2O3) particles with 0.4-㎛ diameter and 3950 kg/㎥ density were treated as aerosols. Removal efficiency was calculated for different gas flow rates i.e. 3-6 ㎥/h and liquid flow rates i.e. 0.009-0.025 ㎥/h. Experimental results depict that aerosols removal efficiency increases with the increase in throat velocity and liquid head. While at lower air flow rate of 3 ㎥/h, removal efficiency decreases with the increase in liquid head. A theoretical model of venturi scrubber was also employed and experimental results were compared with mathematical model. Experimental results are found to be in good agreement with theoretical results.

A Study on the Characterisitcs of Electircal Discharge Machining (Sic/A1 복합재료의 방전가공 특성에 관한 연구)

  • 우정윤;왕덕현;김원일;이규창
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.3-7
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    • 1996
  • Metal Matrix Composite(MMC) material of 30% SiC particulate based on A1 matrix was machined by drilling and Electrical Discharge Machining (EDM) processes. When drilling process was executed, surface fracture due to brittle property near the bottom was found. It was also found the possiblity of difficult shape of EDM process for MMC material, but few the research about basic EDM characteristics. Material Removal Rate(MRR) was examined for different conditions and the surface morphology was evaluated by roughness values and Scanning Electron Microscopy(SEM) research. The higher the current is, the more MRR was obtained but the higher MRR was showed around 0.45 duty factor. The average roughness of EDMed surface was slightly changed with increased pulse current and increases with duty factor. The SEM photographs of EDMed surface showed recast region after melting.

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An Experiment on Performance Evaluation of a Vapor Condensation Type Air Washer System for Semiconductor Clean Rooms (반도체 클린룸용 수증기 응축식 에어와셔 시스템의 성능평가)

  • Yeo, Kuk-Hyun;Park, Sang-Tae;Yoo, Kyung-Hoon;Son, Seung-Woo
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.442-447
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    • 2006
  • In semiconductor manufacturing clean rooms, it becomes important to remove airborne molecular contaminants as well as particulate contaminant in outdoor air introduced into clean rooms. One suitable control technique for these chemical contaminants is air washing by water in an outdoor air handling unit. In order to enhance the removal efficiency of chemical contaminants the effect of adding a heating and humidifying process before an air washer was examined.

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A Study on Selective Catalytic Reduction on Diesel Particulate Filter Catalyst and Coating Technology the Removal of Particulate Matters and NOx for Old Special Cargo Vehicles (노후 특수·화물 차량 PM/NOx 저감을 위한 SDPF 촉매 및 코팅 기술 연구)

  • Jeong, Kwanhyoung;Seo, Philwon;Oh, Hungsuk;Kim, Jongkook;Kang, Soyeon;Kang, Jeongho;Kim, Hyunjun;Shin, Byeongseon
    • Applied Chemistry for Engineering
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    • v.32 no.6
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    • pp.695-699
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    • 2021
  • In this study, Selective Catalytic Reduction on Diesel Particulate Filter (SDPF) after-treatment system was introduced to simultaneously remove NOx and Particulate Matters (PM) emitted from trucks and special cargo vehicles using old engine. First, in order to select an Selective Catalytic Reduction (SCR) catalyst for SDPF, the de-NOx performance of V/TiO2 and Cu-Zeolite catalysts were compared, and the SCR catalyst characteristics were analyzed through Brunauer Emmett Teller (BET), X-ray Diffraction (XRD) and NH3-TPD (Temperature Programmed Desorption). From the activity test results, the Cu-zeolite catalyst showed the best thermal stability. For optimal coating of SDPF, slurry was prepared according to the target particle size. From the coating stability and back pressure test results of SDPF according to the amount of SCR coating, As a result of comparing coating stability, back pressure, and de-NOx performance by producing A, B, and C samples for each loading amount of the SDPF catalyst, the best results were found in the B sample. The engine dynamometer test was conducted for the optimal SDPF after-treatment system, and the test results satisfied Eu-5 regulations.

The Nutrient Removal of Mixed Wastewater composed of Sewage and Stable Wastewater using SBR (SBR을 이용한 하수와 우사폐수로 구성된 혼합폐수의 영양소 제거)

  • 김홍태
    • Journal of Environmental Science International
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    • v.8 no.5
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    • pp.617-623
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    • 1999
  • This study was carried out to obtain the optimal operating parameter on organic matters and nutrient removal of mixed wastewater which was composed of sewage and stable wastewater using SBR. A laboratory scale SBR was operated with An/Ae(Anaerobic/Aerobic) ratio of 3/3, 2/4 and 4/2(3.5/2.5) at organic loading rate of 0.14 to 0.27 kgBOD/$m^3$/d. TCOD/SCOD ratio of mixed wastewater was 3, so the important operating factor depended upon the resolving the particulate parts of wastewater. Conclusions of this study were as follows: 1) For mixed wastewater, BOD and COD removal efficiencies were 93-96% and 85-89%, respectively. It was not related to each organic loading rate, whereas depended on An/Ae ratio. During Anarobic period, the amount of SCOD consumption was very little, because ICOD in influent was converted to SCOD by hydrolysis of insoluble matter. 2) T-N removal efficiencies of mixed wastewater were 55-62% for Exp. 1, 66-76% for Exp. 2, and 67-81% for Exp. 3, respectively. It was found that nitrification rate was increased according to organic concentration in influent increased. Therefore, the nitrification rate seemed to be achieved by heterotrophs. During anoxic period, denitrification rate depended on SCOD concentration in aerobic period and thus, was not resulted by endogenous denitrification. However, the amount of denitrification during anaerobic period were 3.5-14.1 mg/cycle, and that of BOD consumed were 10-40 mg/cycle. 3) For P removal of mixed wastewater, EBPR appeared only Mode 3($3^*$). It was found that the time in which ICOD was converted to VFA should be sufficient. For mode 3 in each Exp., P removal efficiencies were 74, 87, and 81%, respectively. But for 45-48 of COD/TP ratio in influent, P concentration in effluent was over 1 mg/L. It was caused to a large amount of ICOD in influent. However, as P concnetration in influent was increased, the amounts of P release and uptake were increased linearly.

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A study on the Behavior of Fine Particle used the HEPA Filer (HEPA Filter를 이용한 미세입자 거동에 관한 연구)

  • Kim, Won-Gang
    • Journal of environmental and Sanitary engineering
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    • v.24 no.3
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    • pp.16-27
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    • 2009
  • In this paper, I examined the level of fine dust in medical institutions, educational institutions and multi-purposed facilities to grasp the exact state of the present, and decided the level of air-borne particulate(KSM ISO Standard and ISO Standard 14644-1). We compared new proposed cleaner equipped with HEPA Filter with general cleaner and analyzed the rate of removal according to height, air volume and the equipment with the compulsive air intake. Through this comparison, I reached the conclusion as follows: 1. According to the examination, the fine dust of medical institutions, educational institutions and multi-purposed facilities in Kwang Ju is class 9. 2. The filter used in general cleaner on the market is that of HEPA-type, and its removal efficiency for fine particles($0.3{\sim}0.5{\mu}m$) is very low. 3. In the removal efficiency of new proposed cleaner equipped with HEPA Filter, the higher it is, the better, especially more than 180cm in height. 4. In case it is operated for 5 minutes under the condition of the space of $9.4m^{3}$ and the maximum air volume equipped with two induction pipes, we can keep the air cleanness level of 5 ~ 6. 5. To maintain the air cleanness for a long time, if we first operate for 5 minutes at maximum air volume and then operate at medium maximum air volume, we can keep the air cleanness with low energy.

A Study on the Development of Fouling Analysis Technique for Shell-and-Tube Heat Exchangers (다관원통형 열교환기의 파울링 해석기법 개발 연구)

  • Hwang, Kyeong-Mo;Jin, Tae-Eun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.2
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    • pp.167-173
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    • 2004
  • Fouling of heat exchangers is generated by water-borne deposits, commonly known as foulants including particulate matter from the air, migrated corrosion produces; silt, clays, and sand suspended in water; organic contaminants; and boron based deposits in plants. The fouling is known to interfere with normal flow characteristics and reduce thermal efficiencies of heat exchangers. This paper describes the fouling analysis technique developed in this study which can analyze the thermal performance for heat exchangers and estimate the future fouling variations. To develop the fouling analysis technique fur heat exchangers, fouling factor was introduced based on the ASME O&M codes and TEMA standards. For the purpose or verifying the fouling analysis technique, the routing analyses were performed for four heat exchangers in several nuclear power plants; two residual heat removal heat exchangers of the residual heat removal system and two component cooling water heat exchangers of the component cooling water system.

Performance and microbial community analysis for fouling characteristics in a full-scale flat sheet membrane bioreactor (실규모 flat sheet MBR 운영 효율과 Fouling 특성을 위한 미생물 군집 평가)

  • Seungwon Kim;Jeongdong Choi
    • Journal of Korean Society of Water and Wastewater
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    • v.37 no.6
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    • pp.325-334
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    • 2023
  • Membrane bioreactor (MBR) provides the benefits on high effluent quality and construction cost without the secondary clarification. Despite of these advantages, fouling, which clogs the pore in membrane modules, affects the membrane life span and effluent quality. Studies on the laboratory scale MBR were focused on the control of particulate fouling, organic fouling and inorganic fouling. However, less studies were focused on the control of biofouling and microbial aspect of membrane. In the full scale operation, most MBR produces high effluent quality to meet the national permit of discharge regulation. In this study, the performance and microbial community analysis were investigated in two MBRs. As the results, the performance of organic removal, nitrogen removal, and phosphorus removal was similar both MBRs. Microbial community analysis, however, showed that Azonexus sp. and Propionivibrio sp. contributed to indirect fouling to cause the chemical cleaning in the DX MBR.

A Study on Estimating Diffuse Pollution Loads Removal by Road Vacuum Cleaning (도로청소에 의한 비점오염부하 삭감량 산정방법 연구)

  • Lee, Taehwan;Cho, Hong-Lae;Jeong, Euisang;Koo, Bhon K.;Park, Baekyung;Kim, Yongseok
    • Journal of Korean Society on Water Environment
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    • v.33 no.2
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    • pp.123-129
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    • 2017
  • The purpose of this study is to identify potential methodologies to reasonably estimate the effectiveness of road vacuum cleaning in terms of pollution loads reduction. In this context, this study proposes two empirical equations to estimate the amount of diffuse pollution loads removed by road vacuum cleaning. The proposed equations estimate the removed amount of pollution loads respectively taking into consideration of: a) the distance of road vacuum cleaning; and b) the amount of road-deposited sediment(RDS). All of the parameters in these equations were evaluated based on results of field monitoring and laboratory analyses, except for the RDS generation rate. The results of this study suggest that pollutant removal efficiency is 46.3% for $BOD_5$ and 56.4% for TP; discharge ratios for particulate and dissolved $BOD_5$ are 35.0% and 21.2%, respectively; discharge ratios for particulate and dissolved TP are 35.0% and 19.4%, respectively. Average concentrations of pollutants in RDS are $BOD_5$ 977.3 mg/kg and TP 317.6 mg/kg. Some results of a case study imply that both equations can be potentially useful if the adopted parameters are reasonably evaluated. In particular, the RDS generation rate should be evaluated based on monitoring data collected from various road conditions.