• 제목/요약/키워드: 용존공기부상

검색결과 34건 처리시간 0.095초

용존공기부상(DAF) 공정을 이용한 생물학적 플록의 부상분리 (Flotation Separation of Biological Floc Using the Dissolved Air Flotation Process)

  • 곽동희;김성진;임영환
    • 상하수도학회지
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    • v.18 no.5
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    • pp.649-655
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    • 2004
  • The behavior of biological particles in DAF (dissolved air flotation) process was analyzed by employing PBT (Population balance theory). After decline growth phase of activated sludge, the value of the initial collision-attachment efficiency was increased over than 0.35 corresponding relatively high value in the whole life cycle of microorganism. For practical application of DAF as a solid separation process. It is desirable that microbial particles should be operated to perform high solid removal efficiency in biological wastewater treatment.

국산 DAF 펌프가 적용된 연속 DAF 공정의 운전 조건 (Operation Conditions for Continuous DAF Process with Domestic DAF Pump)

  • 안대명;이창한;안갑환;조석호;김성수
    • 상하수도학회지
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    • v.18 no.2
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    • pp.242-246
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    • 2004
  • Dissolved air flotation (DAF) is an effective solid/liquid separation process for low density particles, such as algal flocs, humus materials and clay particles produced from low turbidity water. The fraction of humic substances for natural organic matters (NOMs) are considered problematic in water because it can readily react with chlorine to form harmful by-products (trihalomethanes) and can be exposed to undesirable color, tastes and odors in drinking water. A broad class of NOMs includes fulvic acid, humic acid and humin. This paper will discuss the results from a study that performed with a DAF pump process using synthetic wastewater contained humic substance. Batch jar tests were performed to evaluate coagulant dose and recycle ratio on flotation efficiency.

DAF 공정에서 무기 고형입자의 유체역학적 충돌효율과 부상특성 (Hydrodynamic Collision Efficiency and Flotation Characteristics of Inorganic Particles in DAF Process)

  • 곽동희;김성진;이화경;정흥조;이재욱;정팔진
    • 상하수도학회지
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    • v.16 no.6
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    • pp.655-662
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    • 2002
  • Separation characteristics of inorganic particles occurred during heavy rainwater were investigated in DAF (dissolved air flotation) process. In order to remove the inorganic particles effectively, the collision and flotation efficiencies were examined from a hydrodynamic point of view. Generally, the collision efficiency increased with floc size under the variation of fluid dynamic conditions including inertial force. However, more precise model should be required to analysis the collision efficiency expressed both the physical properties for inorganic particles and hydrodynamic conditions for a reactor.

팽화슬러지의 용존공기부상과 침전에 미치는 굴패각 첨가의 영향 (Effect of Oyster Shell Addition on the Dissolved Air Flotation and Sedimentation of Bulking Sludge)

  • 김동석;박영식
    • 대한환경공학회지
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    • v.29 no.1
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    • pp.82-88
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    • 2007
  • 용존공기부상법과 중력침전법을 이용하여 제지공장의 팽화슬러지를 농축에서 폐 굴패각 분말을 첨가제 사용하였을 때의 효과를 조사하였다. 굴패각의 투입량과 크기분포와 같은 인자가 연구되었다. 혼합 굴패각(크기 범위 : $\sim250{\mu}m$)의 최적 투입량은 0.8 g/L인 것으로 나타났다. 침전공정에서 굴패각 5.0 g/L 첨가시 농축 슬러지 농도는 3.25배 증가하였다. 용존공기부상법에서 5.0 g/L의 굴패각 첨가시 Buckler funnel test 장치를 이용하여 측정한 슬러지의 함수율은 95.5%에서 82.7%로 감소되었다. 혼합 굴패각을 4가지 크기($\sim53{\mu}m$, $53\sim106{\mu}m$, $106\sim150{\mu}m$, $150\sim250{\mu}m$)로 나누었을 때 부상과 탈수공정에서 최적 굴패각 입도 범위는$53\sim106{\mu}m$로 나타났다.

DAF 펌프를 이용한 실규모 용존공기부상 공정의 전처리 조건 (Pretreatment Condition in the Full Scale Dissolved Air Flotation Process Using a DAF Pump)

  • 이창한;안대명;김성수;조석호;안갑환
    • 대한환경공학회지
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    • v.31 no.1
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    • pp.58-63
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    • 2009
  • 용존공기부상(Dissolved Air Flotation)은 조류, 휴믹물질, 및 저밀도 입자가 포함된 원수의 처리에서 침전지보다 우수한 성능을 가지는 공정이다. 본 연구는 실험실과 실규모의 DAF 펌프형 시스템을 이용하여 정수처리공정의 전처리(응집/응결) 조건에 따른 처리효율을 비교하여 나타하였다. 실규모 DAF 펌프형 시스템(Full scale DAF pump system ; F-DAF)은 처리용량과 수력학적 부하량을 각각 5,000 톤/일과 10 m/hr이며, F-DAF는 D 정수장의 원수에서 전처리(혼화/응집) 및 운전성능을 최적화하기 위해 운전하였다. 실험실 규모의 실험결과는 원수 탁도 13.8~56.3 NTU에서 최적 PSO-M 주입량은 2.7~4.5 mL/$m^3$/NTU이었다. 이와같이 최적 응집제 주입 조건에서 유출수의 탁도를 1.0 NTU 이하로 1개월 동안 유지하며 F-DAF의 운전이 가능하였다.

점토와 조류입자의 제타전위가 부상분리 효율에 미치는 영향 (Effect of Zeta Potential of Clay and Algae Particles on Flotation Efficiency)

  • 최도영;김성진;정흥조;이세일;백도현;이재욱;곽동희
    • 상하수도학회지
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    • v.19 no.4
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    • pp.437-445
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    • 2005
  • Zeta potential is a key parameter of double layer repulsion for individual particles and can usually be used to interpret the trend of coagulation efficiency. This study focused on the measurement of zeta potential of algae and clay under various experimental conditions including water characteristics (pure water, stream water, reservoir water) and coagulant dose (10~50 mg/L). Results showed that the variation of zeta potential was highly sensitive depending on the water characteristics and coagulation conditions. Zeta potential of two genera of algae (anabaena sp. and microcystis sp.) were changed highly with coagulant dosage, especially. On the basis of trajectory analysis, bubble-floc collision efficiency simulated in terms of zeta potential was fitted well with removal efficiency of chlorophyll-a from algae particles. It was found that the control of zeta potential was important for effective removal of algae particles.

해수담수화 전처리로서 DAF공정에서 고온의 해수에 대한 영향 특성 (Temperature Effect in the process of DAF as pretreatment of SWRO)

  • 박현진;독고석
    • 상하수도학회지
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    • v.26 no.6
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    • pp.807-813
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    • 2012
  • Flocculation and flotation are used as pretreatment steps prior to the reverse osmosis (RO) process. During seawater treatment, high temperature can change the water chemistry of seawater during the process of coagulation. It also affects bubble volume concentration (BVC) and bubble characteristics. Coagulants such as alum and ferric salts at $40^{\circ}C$ can also change flux rates in the seawater reverse osmosis (SWRO) process. In this study, the bubble characteristics in dissolved air flotation (DAF), used as a SWRO pretreatment process, were studied in synthetic seawater at $20^{\circ}C$ and $40^{\circ}C$. The flux of an RO membrane was monitored after dosing the synthetic seawater with coagulants at different temperatures. Results showed that BVC increases as the operating pressure increases and as the salt concentration decreases. The bubble size released at $40^{\circ}C$ is far smaller than that at $20^{\circ}C$The addition of a ferric salt is effective for turbidity removal in synthetic seawater at $20^{\circ}C$; it is more effective than alum. When synthetic seawater was dosed with a ferric salt, the RO membrane flux increased by 27 % at $40^{\circ}C$.