• Title/Summary/Keyword: 표면부하율

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Effect of Bubble Size in DAF (DAF에서 기포크기의 영향)

  • Park, Yong-Hyo;Han, Moo-Young
    • Journal of Korean Society of Water and Wastewater
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    • v.17 no.4
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    • pp.528-533
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    • 2003
  • Bubble size is one of the most important parameters affecting DAF (Dissolved-Air-Flotation) process. It is generally known that small bubbles are preferred. However, the fact seems to be based on the particle removal efficiency at contact zone only, without considering separation zone. Besides, the effect of bubble size on the overall DAF process has not been fully investigated yet. Therefore, the effect of bubble size on collision efficiency, collision chances, and surface loading rate is calculated using theoretical models, and the results are discussed in this paper.

Development and Lab-scale Plant Study of Coagulation Sedimentation Module using Cyclone (선회류를 이용한 응집침전모듈의 개발 및 실증 연구)

  • Moon, Jinyoung;Cho, Young-Gun;Song, Seung-Jun;Kim, Jin-Han
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.5
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    • pp.3336-3344
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    • 2014
  • The purpose of this study is small scale coagulation module is developed and demonstrated through a lab-scale test. Recent as a sewage treatment rate increases, have heightened the interest in the necessity on the nonpoint source and developing a small processing unit has been increased. Coagulation sedimentation module in this study is additional growth of floc through swirling in the outside zone, reduction of microstructure floc number and the internal settling zone through vertical/level flow complex sedimentation method after the coagulation process precipitation method as an effective high separation efficiency can be divided was also assessed. Coagulation sedimentation module can increase the load factor was 4.4 times compared to conventional clarifier base on the same volume and surface area through vertical/level flow. In this study, this process was selected formation and maintenance of swirling and uniform flow distribution in the internal settling zone as an important design factor, to derive its FLUENT was used to characteristics of the flow model. Through the simulation of swirling, influent velocity, dimensions of external basin, hopper depth of bottom cone was determined and through analysis of velocity distribution, flow distribution detailed specifications are derived like as diameter and number of effluent hole. Lab-scale($120{\ell}/hr$) test results, influent of 300~800 NTU to less than 10 NTU without polymer feeding was able to operate in the 20minutes retention time(surface loading rate $37.3m^3/m^2$-day), and through analysis FLUENT the possibility of using design parameters were derived.

Evaluation of Design Parameter on Residuals Treatment Facilities in Membrane Water Treatment Plants (막여과 정수장에서의 배출수처리시설 설계인자 평가)

  • Moon, Yong-Taik;Seo, In-Seok;Kim, Hong-Suck;Park, No-Suk;Ahn, Hyo-Won
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.1
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    • pp.138-146
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    • 2006
  • The characteristics of backwash and concentrate discharges depend upon the quality of the water being treated and the net recovery of the membrane system. This paper is to indicate a design methods on the capacities of residuals treatment facilities in membrane processes for drinking water. We operated a demonstration membrane plant with a recovery rate of 90% for designing G-water treatment plant. We investigated on design parameter (optimum coagulant dosage and surface loading rate etc.) to design efficiently the residuals treatment facilities. The settling test was conducted with 1m columns dosing PACl to kaolin and membrane residuals under the experimental condition that discharge permit was under a 60mg/L. When the quantity of membrane residuals was $1,575m^3/day$, the estimated results for 1st thickener demonstrated the surface loading rate of 14.4m/day, detention time of 5.83hr, available depth of 3.5m.

Reference wetland를 활용한 비점오염저감습지 조성

  • Kim, Yeong-Yun;An, Jung-Su;Park, Tae-Guk;Lee, Yong-Min;Jeong, Yong-Hyeon;Seong, Gi-Jun;Lee, Seok-Mo
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2008.11a
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    • pp.186-190
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    • 2008
  • 낙동강 수계에 존재하는 자연습지의 효과적인 비점오염저감기능에 착안하여 자연습지를 참조습지로 삼아 비점오염원 저감을 위한 인공습지를 조성하였다. 참조습지 조사결과, 면적은 약 83,371 m$^2$, 평균수심 0.97(0.5 $\sim$ 1.9)m, 체적은 80,870 m$^3$이며, 습지면적이 배수구역면적의 6 %로 나타났다. 식생은 부엽 및 침수식물이 우점하고 있으며 강우 시에 유량이 집중되었다. 74.5 mm강우 시 습지로 유입된 유량을 기준으로 체류시간 및 표면부하율을 산정한 결과 각각, 6.24 day, 2.17 m$^3$/m$^2$/day로 나타났다. 퇴적물유형은 CLAY이고, 분급상태는 poorly sorted로 나타났다. 또한 유기물함량 및 미생물활성도(탈수소효소)도 각각 12.19 %, 1.63 $\pm$ 0.53 mg/kg로 높게 나타났다. 참조습지의 형상비, 수심분포, 식생유형, 토양특성 등을 반영하여 인공습지를 조성하였다.

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Thickening Characteristics of Activated Sludge by Air Flotation Process (공기부상법을 이용한 활성슬러지의 부상분리 특성)

  • Park, Chanhyuk;Hong, Seok-won;Maeng, Juwon;Lee, Sanghyup;Choi, Yong-su;Moon, Seong-yong
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.5
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    • pp.747-753
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    • 2006
  • Air flotation is a solid-liquid separation process that utilizes up-flow microbubbles to thicken activated sludge and enhance clarification efficiency. Continuous air flotation experiments were performed to investigate the effect of operation parameters such as initial MLSS (mixed liquor suspended solid) concentration, air pressure, surface loading rate, air to solid (A/S) ratio, and flotation time on thickening efficiency. An initial activated sludge concentration ranged from 3,000 to 12,000mgSS/L and thickened sludge concentration varied from 6,400 to 28,100mgSS/L. The result showed that the thickening efficiency was mainly dependent on surface loading rate, A/S ratio, and flotation time. The pressure did not affect the thickening efficiency when it kept in the range of 1.6 to 1.8 bar. Experimental results showed that the thickening efficiency of activated sludge was increased only when the feed sludge concentration exceeded 5,000mgSS/L and the thickened concentration was over 20,000mgSS/L. At this time, SS concentration in the clarified liquid was ranged from 5 to 10mg/L.

High Rate Dissolved Air Flotation (DAF) for the Removal of Algae Species (유입원수 조류제거를 위한 high rate DAF 최적화 연구)

  • Jung, Woosik;An, Ju-Suk;Song, Keun-Won;Oh, Hyun-Je
    • Journal of Korean Society of Water and Wastewater
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    • v.31 no.5
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    • pp.415-419
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    • 2017
  • In recent years there have been large increases in the hydraulic loading rates used to design dissolved air flotation (DAF) facilities for drinking water applications. High rate DAF processes are now available at loading rates of 20 to $40m^3/m^2{\cdot}h$. This research evaluated dissolved air flotation as a separation method for algae and organic compounds from water treatment plants. During the service period of 2016. 5. to 2017. 6., DAF pilot plants ($500m^3/day$) process has shown a constantly sound performance for the treatment of raw water, yielding a significantly low level of turbidity (DAF treated water, 0.21~1.56 NTU). As a result of analyzing the algae cell counts in the influent source, it was expressed at 100-120 cells/mL. In DAF treated water, the removal efficient of alge cell counts was found to be upto 90%. The stable turbidity and algae removal were confirmed by operating the high rate DAF process under the condition of the surface loading rate of $30m^3/m^2{\cdot}hr$.

Performance Evaluation of Lab-scale High Rate Coagulation System for CSOs Treatment (강우유출수의 신속한 처리를 위한 고속응집시스템의 성능 평가 -실험실 규모 장치를 중심으로-)

  • Gwon, Eun-Mi;Oh, Seok-Jin;Cho, Seong-Ju;Lee, Seng-Chul;Ha, Sung-Ryong;Lim, Chea-Hoan;Park, Ji-Hoon;Kang, Seon-Hong
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.5
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    • pp.629-639
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    • 2010
  • To evaluate the performance of high rate coagulation system(HRCS) for CSOs treatment, fundamental function of lab scale HRCS has been tested by using the Jar tester and lab scale HRCS. The optimum pH dose by Streaming Current value was found in the range of 5.3~6.0 in Fe(III), and in the range of 5.8~6.6 in Al(III) and the optimum chemical dose were 0.44mM of $Al_2(SO_4)_3$ and 0.93mM of $FeCl_3$. The removal efficiencies at optimum $Al_2(SO_4)_3$ dose were 75%($TCOD_{Cr}$), 97%(TP), 95%(SS) and 96%(turbidity), respectively. And the removal efficiency of particles with less than $5{\mu}m$ of diameter was 70% and that of particles with higher than $5{\mu}m$ of diameter was 90%. The optimum alum dose in lab scale HRCS was 150mg/L, and the treatment efficiency was the best with addition of 1.0mg/L polymer. The effect of Micro sand addition was not clear, because the depth of the sediment tank in lab scale HRCS was not long enough. But the HRT of this lab scale HRCS was able to be shorten less then 7 minutes by adding the micro sand. The surface loading rates with respect to using different chemicals were 0.43m/h with alum only, 5.78m/h with alum and polymer and 6.22m/h with alum, polymer and micro sand. As a result, HRCS using coagulant, polymer and micro sand developed in this study was evaluated to be very effective for CSOs treatment.

Determination of Optimun Coagulant Dosage for Effective Water Treatment of Chinyang Lake -The Effect of Coagulant Dosing on Remoaval of Colloidal Pollutants- (진양호소수의 효과적인 정수처리를 위한 최적응집제 주입량 결정 -콜로이드성 오염물질 처리를 위한 응집제 주입효과-)

  • 이원규;조주식;이홍재;허종수
    • Journal of Environmental Science International
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    • v.7 no.6
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    • pp.761-772
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    • 1998
  • This study was performed to determine the optimum coagulant dosing amount for effective treatment of raw water. The removal rate of turbidity and the variations of water qualities according to various dosage of coagulants such as Alum, PAC and PACS were investigated. The optimum coagulant dosing amount to make the lowest turbidity of water were 35mg/ι t of Alum, 30mg/ι of PAC and 10mg/ι of PACS in case of 5 NTU of raw water turbidity, and 30mg/ι of Alum, 25mg/ι of PAC and 10mg/ι of PACS in case of 10 NTU of that, respectively. The removal rates of turbidity at 4 min. and 8 min. of settling time were 10 and 72% of Alum, 44 and 62% of PAC and 25 and 55% of PACS in case of 5 NTU, and 52 and 70% of Alum, 90 and 95% of PAC and 10 and 28% of PACS in case of 10 NTU, respectively. Judging from the settling capability of floc., the reaction time of floe. formation and removal efficiency of turbidity, PAC was evaluated as more effective coagulant than Alum and PACS. Also PAC was regarded as the most effective coagulant when the water supply was changed sharply and the fluctuation of the surface loading occured with wide and sharp in settling basin. pH and alkalinity of the water were decreased with increasing coagulants dosage. But pH and alkalinity were not decreased below 5.8 which is the standard for drinking water quality, and 10mg/ι which is the limit concentration of floc. breakage, respectively. Residual Al of the treated water was decreased with increasing coagulants dosage in case of 5 and 10NTU of raw water turbidity. $KMnO_4$ consumption of the water was decreased with increasing coagulants dosage. The reduction rate of $KMnO_4$ consumption at the optimum coagulants dosage were 39% of Alum. 18% of PAC and 11% of PACS in case of 5 NTU of raw water turbidity, and 42% of Alum, 27% of PAC and 36% of PACS in case of 10 NTU of that, respectively. Any relationship was not found between the removal rate of turbidity and KMnO$_4$ consumption. TOC of the water was a bit decreased with increasing coagulants dosage up to 30mg/ι but not changed above 30mg/ι of coagulants dosage. The degree of TOC reduction was increased in the order of Alum, PAC and PACS treatment. Zeta potential of the colloidal floe. at the optimum coagulants dosage was in the range of -20~-15mV in case of 5 NTU of raw water turbidity and 0~0.5mV in case of 10 NTU of that. respectively. Although the kinds and dosages of coagulants were different, zeta potential range were fixed under the conditions of the best coagulation efficiency.

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A Study on Management of Seafood Wastewater Treatment Facility using Submerged MBR (침지식 MBR을 이용한 수산물 폐수처리장 운영에 관한 연구)

  • Choi, Yong-Bum;Lee, Hae-Seung;Han, Dong-Joon;Kwon, Jae-Hyouk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7227-7236
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    • 2015
  • The survey revealed that, due to the discharge characteristics of seafood wastewater, irregular inflow loads were caused, making it difficult to treat the wastewater safely. It is crucial for the operation of pressure and floating tanks for the treatment of high-concentration organic wastewater such as seafood wastewater. The survey of operation factors for the pressure and floating tanks revealed this: A/S ratio 0.05 (design criteria 0.01), the pressurized air pressure 8bar(design criteria 6bar), the pressure tank pressure 6bar (design criteria 4.5bar), and HRT 60sec(design criteria: 10sec). Also, the recirculation rate was changed to over 40%(design criteria: 30%), and the surface load rate was changed to under $13.7m^3/m^2{\cdot}hr$(design criteria: under $17.7m^3/m^2{\cdot}hr$); thus, compared to the initial design criteria, the operation factors were changed according to inflow characteristics, thus enhancing the pressure and floating tank performance. The survey of inflow load revealed BOD 140.7%, $COD_{Mn}$ 120.32%, and SS 106.3%, compared to the inflow design criteria, as well as T-N 135.5% and T-P173.3%, higher than the design criteria. The survey of the treatment facility annual operation cost revealed high portions in sludge treatment cost(27.7%) and chemicals costs(26.0%), and the sludge treatment cost will likely further increase due to the ban on ocean dumping. The unit cost for the treatment of seafood wastewater was found to be KRW 3,858 per ton, more than 27 times higher than the sewage treatment cost(KRW 142.6/ton), presumably because the seafood wastewater contains high-concentration organic substances and nutritive salts.