• Title/Summary/Keyword: Dissolved air flotation

Search Result 82, Processing Time 0.106 seconds

Development of Dissolved Air Flotation Technology from 1st Generation to the Newest or 3rd One (Very Thick Microbubble Bed) with High Flowrates DAF in Turbulent Flow Conditions (차세대 고효율 용존공기 부상공정(High Rate DAF)의 개발)

  • Kiuru, H.J.
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.18 no.2
    • /
    • pp.228-234
    • /
    • 2004
  • Dissolved air flotation (DAF), in which suspended solids are removed from water by means of micro-size air bubbles raising slowly up in water and lifting solids from water (smaller than those) attached onto the micro-bubbles as well as those (larger than solids) being attached on these, have been used in water and wastewater since 1920s. The dissolved air flotation technology was originally based on the laminar flow conditions prevailing in water to be treated, but the latest development in that technology has led now to a situation, in which the flow conditions may also be turbulent ones in the modem dissolved air flotation units. Despite of that, the flotation phenomenon used in this unit operation for removal suspended solids from water or wastewater is still the same.

Effect of Sludge Characteristics on the Thickening of Bulking Sludge using DAF (Dissolved Air Flotation) (슬러지의 성상이 DAF(Dissolved Air Flotation)를 이용한 팽화 슬러지 농축에 미치는 영향)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Korean Society on Water Environment
    • /
    • v.22 no.1
    • /
    • pp.97-103
    • /
    • 2006
  • Excess sludge treatment and disposal currently represent a rising challenge for domestic or wastewater treatment plants due to economic, environmental and regulation factors. Conventional gravity sedimentation process has been widely used in sludge thickening. The operation method of the process is very simple, but the process requires long detention time for sludge thickening, uses polymers, and shows low sludge thickening efficiency. To solve the problems, we studied on DAF (Dissolved Air Flotation) system. We use bulking sludge of a paper manufacturing plant. The effects of parameters such as SVI (Sludge Volume Index), storage time, initial concentration and wet density of excess sludge were examined. The results showed that the more SVI was low, the more sludge was thickened. As storage time goes by, SVI was increased and thickening performance was deteriorated. In order to improve flotation performance at high concentration, high recycling ratio and pressure did not increase the concentration due to thickening limitation. The addition of 0.8 g/L of loess was increased flotation efficiency of 1.41 times.

COD, SS and Turbidity Removal of Paper Wastewater Using DAE(Dissolved Air Flotation) (DAF(Dissolved Air Flotation)를 이용한 제지폐수의 COD, SS 및 탁도 제거)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Health Sciences
    • /
    • v.31 no.4 s.85
    • /
    • pp.246-253
    • /
    • 2005
  • The supernatant treatment of recovery process of raw materials of paper plant was studied using DAF (Dissolved Air Flotation) system. We investigated the removal efficiency (COD, SS and turbidity) of the DAF process. The effects of parameters such as A/S ratio, pressure, flotation conditions, coagulant concentration, mixing conditions, size and ratio of packing and nozzle type were examined. The results showed that the optimum A/S ratio and pressure were 0.058 and 4.5-5 atm, respectively. Injection times of pressurized water around 30 s and flotation times around 10 min appeared to be optimal for the DAF operation. Anion polymer addition improved the removal of COD, SS and turbidity. The smaller size and the more packing ratio were enhanced the removal efficiencies. The order of performance of nozzle was full cone > flat > assemble type.

Removal Rates of VOCs(Volatile Organic Compounds) for Treatment Condition using DAF(Dissolved Air Flotation) in Water Treatment (DAF(Dissolved Air Flotation)를 이용한 정수처리에서 처리조건에 따른 VOCs(Volatile Organic Compounds)의 처리효율에 대한 연구)

  • Kim, Mi-Jeong;Jun, Se-Jin
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.13 no.3
    • /
    • pp.91-100
    • /
    • 1999
  • Treatment conditions of DAF(Dissolved Air Flotation) and removal rates of VOCs(Volatile Organic Compounds) in mixed water of H raw water and VOCs were investigated. The used VOCs were benzene, toluene, ethylbenzene, and xylene in aromatic compounds and iso propyl mereaptan, n-butyl mereaptan, dimethyl disulfide, and iso butyl mercaptan in odors. The related parameters include water type, treatment method, clay concentration, pH condition, flocculation time, flotation time, per-cent recycle, water temperature, pressure. The removal rates of VOCs were different on treatment process and water condition. Treatment time was longer, removal rates of VOCs was higher. Water temperature was more important than pressure in DAF parameters. Molecular weight was related with removal rate in several kinds of VOCs were decraesed by competition of each component in II raw water. When algac blooming D water was treated by DAF, TCOD(Total chemical Oxygen Demand) and chorophyll a was removed over 96%.

  • PDF

Thickening of Bulking Sludge using DAF (Dissolved Air Flotation) (DAF(Dissolved Air Flotation)를 이용한 팽화 슬러지 농축)

  • Kim Dong-Seog;Park Young-Seek
    • Journal of Environmental Science International
    • /
    • v.15 no.1
    • /
    • pp.77-84
    • /
    • 2006
  • An effective technique of sludge separation is required for excess sludge of sewage or wastewater plant. The separation of bulking sludge of paper manufacturing plant was studied using DAF(Dissolved Air Flotation) system. The effects of parameters such as nozzle type, A/S(air/solid) ratio. pressure, injection time of pressured water and saturation time were examined. The results showed that the best nozzle type was flat which had small orifice hole, The optimum A/S ratio and pressure were $7.070\times10^{-3}$(recycle ratio of pressured water $20\%$) and 5atm, respectively. Injection times of pressurized water around 20-25 sesc and flotation time of 30 min appeared to be optimal for the DAF operation. The order of performance of packing was 18 mm > 22 mm > 32 mm.

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
    • /
    • v.31 no.5
    • /
    • pp.415-419
    • /
    • 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 $30m^3/m^2{\cdot}hr$.

An Effect of the Micro Bubble Formation Depending on the Saturator and the Nozzle in the Dissolved Air Flotation System (DAF 공정에서 공기포화장치와 노즐 특성 별 미세기포 발생에 미치는 영향)

  • Park, S.C.;Oh, H.Y.;Chung, M.K.;Song, S.L.;Ahn, Y.H.
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.35 no.12
    • /
    • pp.929-936
    • /
    • 2013
  • The saturator and injection nozzle are important facilities on the dissolved air flotation process. To increase the formation of micro bubble, it is required to improve the air dissolving performance in the saturator and keep the pressure uniform from the saturator to the nozzle. This study aimed to evaluate the performance of the saturator and the hydraulic effect of the nozzle and the pipe structure. The air volume concentration, bubble size and bubble residual time were measured in the test. The saturator, which had mounted with the spray nozzle, showed a good performance for bubble formation. Also, the characteristics of micro bubble formation were influenced by pressure uniformity and flow velocity through the orifice in the nozzle.

Effect of Coagulation and Homogenization on the Dissolved Air Flotation and Sedimentation of Bulking Sludge (응집과 균질화가 팽화슬러지의 용존공기부상과 침전에 미치는 영향)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Health Sciences
    • /
    • v.33 no.1 s.94
    • /
    • pp.68-74
    • /
    • 2007
  • The objective of this study is to examine the effect of the coagulation and homogenization in bulking sludge thickening of paper manufacturing plant using DAF(Dissolved Air Flotation) and gravitational sedimentation. The effects of parameters such as dosage of coagulant and homogenization time were examined. The results showed that DAF and sedimentation was affected aluminum sulfate and anion polymer coagulant differently. At the optimum dosage of aluminum sulfate, thickening efficiency of DAF and sedimentation process were increase 1.25 time and 2.02 time, respectively. At the optimum dosage of anion polymer coagulant, thickening efficiency of DAF process was increase 1.35 time, but thickening efficiency at sedimentation was 1.06 time. When anion polymer coagulant of 0.5 mg/l was added in DAF process, water content of sludge was decreased from 96.6% to 90.7% in dewatering process using Buchner funnel test device. After homogenization(20500 rpm, 10 min), Sauter mean diameter of sludge floc was decreased from 631 ${\mu}m$ to 427 ${\mu}m$, however increase of flotation efficiency by DAF was only 1.09 time.