WO2018083514A1 - Procédés de lavage à contre-courant de milieu filtrant compressible synthétique - Google Patents

Procédés de lavage à contre-courant de milieu filtrant compressible synthétique Download PDF

Info

Publication number
WO2018083514A1
WO2018083514A1 PCT/IB2016/001756 IB2016001756W WO2018083514A1 WO 2018083514 A1 WO2018083514 A1 WO 2018083514A1 IB 2016001756 W IB2016001756 W IB 2016001756W WO 2018083514 A1 WO2018083514 A1 WO 2018083514A1
Authority
WO
WIPO (PCT)
Prior art keywords
medium
air
filter
backwash
water
Prior art date
Application number
PCT/IB2016/001756
Other languages
English (en)
Inventor
Christophe D. DESMOTTES
Original Assignee
Suez Treatment Solutions, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Suez Treatment Solutions, Inc. filed Critical Suez Treatment Solutions, Inc.
Priority to CA3003591A priority Critical patent/CA3003591A1/fr
Priority to CN201680064833.1A priority patent/CN108348823B/zh
Priority to AU2016428792A priority patent/AU2016428792B2/en
Priority to EP16836083.2A priority patent/EP3365088A1/fr
Publication of WO2018083514A1 publication Critical patent/WO2018083514A1/fr
Priority to AU2019271953A priority patent/AU2019271953A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
    • B01D24/04—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being clamped between pervious fixed walls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/002—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with multiple filtering elements in parallel connection
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
    • B01D24/04—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being clamped between pervious fixed walls
    • B01D24/042—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being clamped between pervious fixed walls the filtering material being held in a flexible porous bag
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
    • B01D24/10—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being held in a closed container
    • B01D24/12—Downward filtration, the filtering material being supported by pervious surfaces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/46—Regenerating the filtering material in the filter
    • B01D24/4631—Counter-current flushing, e.g. by air
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/46—Regenerating the filtering material in the filter
    • B01D24/4668—Regenerating the filtering material in the filter by moving the filtering element

Definitions

  • the present invention is generally directed to a filter for treatment of an influent. More specifically, the present invention is directed to a synthetic compressible media filter, which may be compressed due to the fluid flow there through.
  • Wastewater treatment may often comprise multiple stages, often referred to as primary, secondary, and tertiary treatment. While primary treatment may include sedimentation and secondary treatment may reduce dissolved and suspended organic compounds in the wastewater, tertiary treatment may improve effluent quality by removing remaining inorganic components before being discharged back to the environment. Tertiary treatment has included various approaches, including sand filtration, further sedimentation tanks, removal of elements (such as excess nitrogen or phosphorus).
  • TSS total suspended solids
  • WWTP municipal wastewater treatment plants
  • TSS and turbidity discharge limitations combined with capital expenditure (CAPEX) and operational expenditure (OPEX) improvements, are the two main drivers for optimization of wastewater tertiary physical treatment.
  • Conventional tertiary filters are organized by four medium characteristics which are cloth, granular, non-granular and membrane.
  • Cloth and single/dual granular medium have filtration rate limits between 3 gpm/ft 2 or 7.3 m 3 /h/m 2 and 6 gpm/ft 2 or 14.7 m 3 /h/m 2 , while membrane filtration ability is constrained by organic loading fouling effects on membrane.
  • Compressible medium filters have been used to provide varying degrees of wastewater filtration.
  • Compressible medium filters in general, involve the use of a synthetic compressible porous fiber material (for example, polyvaniladene), rather than a granular media (for example, sand).
  • the properties of the medium - such as porosity - may be modified by compressing (or releasing) the medium.
  • Such compressible medium filters may be able to achieve increased filtration loading rates. For example, some compressible medium filters have been tested with filtration loading rates up to six times higher (30 gpm/ft 2 or 73.3 m 3 /h/m 2 ) than cloth and granular filters without any additional backwash requirements.
  • the filter medium is generally disposed between two plates, at least one of which may be controllably movable to compress the medium.
  • the mechanical devices necessary to compress the medium may add significant complication to a filtration device, and accordingly cause an increase in the capital expense of building such a filtration device.
  • Some aspects in accordance with some embodiments of the present invention may include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression.
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the backwash may be triggered by one or more of a pressure set point, time set point (2 hours to 24 hours), and/or turbidity set point.
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the backwash may be triggered by one or more of a pressure set point, time set point (2 hours to 24 hours), and/or turbidity set point, wherein the pressure set point may be adjustable based upon factors including filter geometry, medium thickness, solid loading, and/or hydraulic loading, and comprises a set point between 36 to 200 inches of H 2 0.
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the backwash may be triggered by one or more of a pressure set point, time set point (2 hours to 24 hours), and/or turbidity set point, wherein the time set point may be between two (2) to twenty-four (24) hours.
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the backwash may be triggered by one or more of a pressure set point, time set point (2 hours to 24 hours), and/or turbidity set point, wherein the turbidity set point may be less than six (6) or between five (5) and fifteen (15) Nephelometric Turbidity Units (NTU).
  • NTU Nephelometric Turbidity Units
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the air and water wash sequence may comprise breaking the medium and washing the medium.
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the air and water wash sequence may comprise breaking the medium and washing the medium, wherein breaking the medium comprises using water and air flow to generate forces to break the medium free from a compressed stage and washing the medium comprises combining water received in the filter medium from the backwash pump and air from the air scour blower to create motion patterns to cause collision of the filter media.
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the air and water wash sequence may comprise breaking the medium and washing the medium, wherein breaking the medium comprises using water and air flow to generate forces to break the medium free from a compressed stage and washing the medium comprises combining water received in the filter medium from the backwash pump and air from the air scour blower to create motion patterns to cause collision of the filter media, and wherein breaking the medium may use a water flow of 10 gpm/ft 2 and air flow of 15 scfm for a period of time, such as for between one (1) to five (5) minutes.
  • Some aspects may further include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the air and water wash sequence may comprise breaking the medium and washing the medium, wherein breaking the medium comprises using water and air flow to generate forces to break the medium free from a compressed stage and washing the medium comprises using the backwash pump to provide a backwash flow into the medium and the air scour blower to provide air into the medium at flow rates of approximately 10 gpm/ft 2 and the air scour blower provides air flow of approximately 10 scfm/ft 2 , causing bubbles which carry at least some of the media to the top of the filter, at which point the air escapes from the filter and the media sinks downward, striking media ascending with air bubbles.
  • the air and water wash sequence may comprise breaking the medium and washing the medium, wherein breaking
  • Some aspects in accordance with some embodiments of the present invention may include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein the air purge sequence comprises removing substantially all of the air entrapped in the medium by providing an upward water flow from the backwash pump to the medium for a period of time (such as between one (1) and ten (10) minutes) at a rate of 5 to 10 gpm/ft 2 .
  • a period of time such as between one (1) and ten (10) minutes
  • Some aspects in accordance with some embodiments of the present invention may include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, wherein medium compression comprises a transition between backwash and filtration processes of the filter system, during which excess backwash water is drained from the filter and influent flow is provided above the usual rate in order to compress the media quickly and eliminate the need for a water to waste sequence.
  • Some aspects in accordance with some embodiments of the present invention may include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, wherein medium compression comprises a transition between backwash and filtration processes of the filter system, during which excess backwash water is drained from the filter and influent flow is provided above the usual rate in order to compress the media quickly and eliminate the need for a water to waste sequence, further comprising introducing raw water into the filter, and wherein the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium.
  • Some aspects in accordance with some embodiments of the present invention may include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein medium compression comprises a transition between backwash and filtration processes of the filter system, during which a water to waste sequence is used to minimize turbidity release of the filter effluent.
  • Some aspects in accordance with some embodiments of the present invention may include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the method comprising at least three sequences of: air and water wash; air purge; and medium compression, wherein medium compression comprises a transition between backwash and filtration processes of the filter system, during which a water to waste sequence comprising sending backwash water directly to waste after flowing through the filter.is used to minimize turbidity release of the filter effluent.
  • aspects may also include: a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the backwash being triggered by one or more of a pressure set point, time set point, and/or turbidity set point, the backwash method comprising at least three sequences of: an air and water wash sequence, comprising breaking the medium and washing the medium; an air purge sequence, comprising removing substantially all of the air entrapped in the medium by providing a flow of water from the backwash pump to the medium for a period of time; and a medium compression sequence, compressing the medium to achieve desired filtration rates, while avoiding exposing the medium to air, the medium compression sequence comprising introducing raw water into the filter, where the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium.
  • aspects may also include: a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the backwash being triggered by one or more of a pressure set point, time set point, and/or turbidity set point, the backwash method comprising at least three sequences of: an air and water wash sequence, comprising breaking the medium and washing the medium; an air purge sequence, comprising removing substantially all of the air entrapped in the medium by providing a flow of water from the backwash pump to the medium for a period of time; and a medium compression sequence, compressing the medium to achieve desired filtration rates, while avoiding exposing the medium to air, the medium compression sequence comprising introducing raw water into the filter, where the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium, wherein breaking the medium comprises using water received from the backwash pump and air flow from the air scour blower to generate forces
  • aspects may also include: a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the backwash being triggered by one or more of a pressure set point, time set point, and/or turbidity set point, the backwash method comprising at least three sequences of: an air and water wash sequence, comprising breaking the medium and washing the medium; an air purge sequence, comprising removing substantially all of the air entrapped in the medium by providing a flow of water from the backwash pump to the medium for a period of time; and a medium compression sequence, compressing the medium to achieve desired filtration rates, while avoiding exposing the medium to air, the medium compression sequence comprising introducing raw water into the filter, where the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium, wherein medium compression comprises a transition between backwash and filtration processes of the filter system, during which excess backwash water is
  • aspects may also include: a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the backwash being triggered by one or more of a pressure set point, time set point, and/or turbidity set point, the backwash method comprising at least three sequences of: an air and water wash sequence, comprising breaking the medium and washing the medium; an air purge sequence, comprising removing substantially all of the air entrapped in the medium by providing a flow of water from the backwash pump to the medium for a period of time; and a medium compression sequence, compressing the medium to achieve desired filtration rates, while avoiding exposing the medium to air, the medium compression sequence comprising introducing raw water into the filter, where the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium, wherein medium compression comprises a transition between backwash and filtration processes of the filter system, during which a water to waste sequence is used
  • Some aspects of the present invention in accordance with some embodiments may include a method of providing backwash to a synthetic compressible medium filter system comprising a filter including compressible filter medium, at least one backwash pump, and at least one air scour blower, the backwash being triggered by one or more of a pressure set point, time set point, and/or turbidity set point, the backwash method comprising at least three sequences of: an air and water wash sequence, comprising breaking the medium and washing the medium, wherein: breaking the medium comprises using water received from the backwash pump and air flow from the air scour blower to generate forces to break the medium free from a compressed stage; and washing the medium comprises combining water received in the filter medium from the backwash pump and air from the air scour blower to create motion patterns to cause collision of the filter media, wherein the air scour blower provides air into the medium, causing bubbles which carry at least some of the media to the top of the filter, at which point the air escapes from the filter and the media sinks downward
  • Some aspects may also include a system for providing backwash to a synthetic compressible media filter system comprising a compressible filter medium, one or more backwash pumps, and one or more air scour blowers, the system characterized by performing a backwash protocol comprising: air and water wash; air purge; and medium compression.
  • Some aspects of the present invention may include a system for providing backwash to a synthetic compressible media filter system comprising a compressible filter medium, one or more backwash pumps, and one or more air scour blowers, the system characterized by performing a backwash protocol comprising: air and water wash; air purge; and medium compression, wherein the air and water wash sequence comprises breaking the medium and washing the medium, the air purge sequence comprises removing substantially all of the air entrapped in the medium by providing a flow of water from the backwash pump to the medium for a period of time, and the medium compression sequence comprises compressing the medium to achieve desired filtration rates, while avoiding exposing the medium to air, the medium compression sequence comprising introducing raw water into the filter, where the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium.
  • a backwash protocol comprising: air and water wash; air purge; and medium compression
  • the air and water wash sequence comprises breaking the medium and washing the medium
  • the air purge sequence comprises removing substantially all of the
  • Some aspects of the present invention may include a system for providing backwash to a synthetic compressible media filter system comprising a compressible filter medium, one or more backwash pumps, and one or more air scour blowers, the system characterized by performing a backwash protocol comprising: air and water wash; air purge; and medium compression, wherein the air and water wash sequence comprises breaking the medium and washing the medium, the air purge sequence comprises removing substantially all of the air entrapped in the medium by providing a flow of water from the backwash pump to the medium for a period of time, and the medium compression sequence comprises compressing the medium to achieve desired filtration rates, while avoiding exposing the medium to air, the medium compression sequence comprising introducing raw water into the filter, where the backwash water and introduced raw water provide enough energy to compress the medium without introduction of air into the medium, wherein breaking the medium comprises using water received from the backwash pump and air flow from the air scour blower to generate forces to break the medium free from a compressed stage; and washing the medium comprises combining water received in
  • Figure 2 illustrates an exemplary compressible media filtration system, in accordance with some embodiments of the present invention.
  • Figure 3 illustrates an exemplary compressible media filtration system, in accordance with some embodiments of the present invention.
  • the present invention is directed to a synthetic compressible medium filter that does not require the use of additional mechanical devices to compress the medium. Instead, in accordance with aspects of some embodiments of the present invention, the medium is compressed by the fluid flow, thereby obviating the need for additional machinery, and providing for more efficient backwashing operations (thereby reducing increased operating expenses).
  • aspects in accordance with some embodiments of the present invention may comprise a synthetic compressible medium filter (SCMF) capable of hydraulic rate of approximately 40 gpm/ft 2 .
  • SCMF may produce effluent with a total suspended solids (TSS) of less than approximately 5 mg/L, with a turbidity of less than 2 NTU.
  • the SCMF may operate to provide an effluent with a TSS range of 1 mg/L to 4 mg/L, with a turbidity between 1 - 1.9 NTU.
  • SCMF in accordance with some embodiments of the present invention may utilize less than 7% (in accordance with some embodiments, utilize only 3%) of volume of water treated for backwash.
  • Initial Testing comprised the use of a 12" or 30.5 cm diameter column. The specific media design and selection was based at least in part on solid removal and medium aptitude to compress when subjected to 13 gpm/ft 2 or 31.8 m 3 /h/m 2 filtration rate.
  • the filter media may be comprised of synthetic fibers held together by a bead.
  • filter media 100 may comprise fibers 110 may be fed through a bead 120, such that the bead retains together.
  • the fibers may comprise any suitable filtration material, testing has shown that polyethylene terephthalate, with a fiber density of approximately 1.38 g/cm 3 works well.
  • the bead may comprise any suitable material, though in testing a bead comprising atactic polystyrene was utilized.
  • the specific type of material, density, size, etc. does not impact the claimed invention; indeed, any material and/or size may be utilized without deviating from the present invention.
  • system 200 may comprise one or more synthetic compressible medium filters 210, one or more air scour blowers 220, and one or more backwash pumps 230.
  • influent may be received by conduit 240 into the synthetic compressible medium filter, and a treated effluent may exit the system via conduit 250.
  • a system 300 may comprise similar components as in Figure 2.
  • System 300 may comprise a synthetic compressible medium filter 310, which in turn may comprise two (2) synthetic compressible medium filters 311, 312 plumbed in parallel.
  • one of the filters 311 would be the duty filter, while the second 312 would be an inline spare.
  • air scour blower 320 may comprise two (2) blower units 321, 322, and backwash pump 330 may comprise two (2) backwash pumps 331, 332, each comprising one duty apparatus and one inline spare.
  • Inputs to system 300 may comprise influent 341, which may for example comprise blowdown water from cooling towers. Additional influent 342 may be received from filter and polymer feed system as well, in order to additionally treat the wastewater. Influent 341 and 342 may be combined and provided directly to the synthetic compressible medium filter 311, 312. [0045] Additional water 343 may be input from service water/fire water tanks and utilized to provide an input to filter backwash tank 344. Water in the filter backwash tank 344 may be drawn by the backwash pumps 331, 332 to backwash the filters 311, 312.
  • Effluent 351 may flow from the synthetic compressible medium filters 311, 312 and may leave the system.
  • Backwash waste 352 may also exit the system 300.
  • backwash pumps and air scour blowers may be used, testing was completed utilizing two (2) horizontal centrifugal filter backwash pumps, with a capacity of 1850 gpm at 30 psi.
  • the backwash air scour blowers may be positive displacement with noise reduction enclosures, with a capacity of 225 SCFM at 7 psi.
  • a pilot test system was designed and built that was capable of filtration rates up to 40 gpm/ft 2 or 97.8 m 3 /h/m 2 .
  • a series of tests were conducted to evaluate the new SCMF technology at 30 gpm/ft 2 or 73.3 m 3 /h/m 2 with/without coagulant and polymer addition, at 35 gpm/ft 2 or 85.6 m 3 /h/m 2 and 40 gpm/ft 2 or 97.8 m 3 /h/m 2 without chemical addition.
  • the present invention utilizes a synthetic compressible medium filter that does not require additional compression mechanisms, but relies upon the fluid flow to provide desirable compression.
  • a pilot unit with a 9 square foot cross section was equipped with uncompressed medium at a thickness of approximately 30 inches. During use, the medium compressed to approximately 12 inches.
  • a filter bed depth may be a function of the solid load, which in turn may be a function of the raw water TSS concentraiton and filtration flow rate. The higher the TSS concentration and the higher the filtration flow rate required, the deeper the media bed in order to perform. As a non-limiting example, bed depths may easily range from 24 - 48 inches.
  • the filter may comprise a down flow unit with a 12 inch or 0.3 m medium thickness after compression made of polypropylene fiber, constituted by a plenum which may collect treated water during filtration and hold air and water during backwash and a filtration/backwash zone.
  • Nozzles (such as, for example, those sold under the Monofloor® trademark) may be used to produce a distributed flow between the plenum and filtration/backwash zone.
  • a media retaining screen may be adequately position above the medium to allocate sufficient media space during backwash. The screen may also maintains hydraulic distribution on the medium during filtration.
  • Backwash processes may comprise multiple steps.
  • a three step backwash may be utilized to provide medium cleaning in the most efficient manner.
  • a phase between backwash and filtration sequences was analysed to promote adequate control improved filtration duration.
  • additional control was established to minimize pressure build up in the filter and ultimately enhance filtration duration.
  • the synthetic compressible media filter design may backwash based upon one or more triggers, which may comprise but are not limited to specified pressure, time, and/or turbidity.
  • the synthetic compressible media filter design may comprise a pressure set point (in inches of H 2 0) that may be adjusted by the operator based on the specifics of the filter.
  • Specifics of the filter that may dictate, affect, or impact backwash cycles based on pressure may include, but are not limited to, (i) filter geometry (filter elevation); (ii) medium thickness (inches) of the filter; (iii) solid loading (kg/ft 2 /hour); and/or hydraulic loading (gpm/ft 2 ).
  • an exemplary set point in accordance with some embodiments of the present invention, may be 68 inches of H 2 0.
  • the synthetic compressible media filter design may comprise a timer set point when backwash may be triggered - for example, regardless of pressure in the filter or turbidity concentration in the effluent.
  • a timer set point may be set at 48 hours.
  • the synthetic compressible media filter design may further comprise an effluent turbidimeter that may monitor the turbidity (for example, by providing continuous monitoring).
  • a set point in nephelometric turbidity unis (NTU)
  • NTU nephelometric turbidity unis
  • a backwash cycle in order to prevent turbidity breakthrough.
  • a value of 6 NTU may be used to trigger backwash.
  • the synthetic compressible media filter design may utilize a backwash cycle or process that may comprise three (3) sequences: (i) air and water wash; (ii) air purge; and/or (iii) medium compression.
  • the air and water wash sequence may start after the pressure activated backwash set point is reached. Note that if the backwash is triggered by either the time or turbidity set points, the air and water wash sequence may be delayed until the pressure in the filter reaches the pressure activated backwash set point. This may be accomplished, for example, by closing a filter effluent valve while maintaining influent into the filter. Once the pressure in the synthetic compressible media filter reaches the pressure set point, the influent flow may be stopped, and then the air and water wash sequence may be begin. In general, the air and water wash sequence may comprise two steps of (i) breaking the medium; and (ii) washing the medium.
  • breaking the medium may refer to breaking the media free from the compressed stage.
  • the media and solids may be compressed together against the filter wall and plenum.
  • Water and air flow may be used to generate the forces necessary to break the media free from this compressed stage.
  • the water and airflow - as well as duration of each - may be adjusted by the filter operator (for example, based on medium thickness). For example, a water flow of 10 gpm/ft 2 and 15 scfm for three (3) minutes may be utilized.
  • Washing the medium may be accomplished to release entrapped solids from the media fibers.
  • the density of the synthetic media may be higher than the density of water (even slightly so), and accordingly both water and air may be combined to create motion patterns to enhance media collisions.
  • Air bubbles may carry the media to a screen at the top of the filter. As the bubble escapes through the screen, the media may be retained, which may then sink back towards the plenum and collide with other rising media. When the descending media strikes the ascending media, an efficient release of the entrapped solids may occur.
  • typical backwash flowrates may be 10 gpm/ft 2 for water and 10 scfm/ft 2 for air.
  • air and water flow rates maybe adjustable by a filter operator based at least in part on filtration flow rates and solids loading.
  • the second sequence of backwashing may include an air purge.
  • air purge In general it may be important to expel air from the filter before compressing the medium for filtering use. This may be desirable since, as a down-flow filter, remaining air may not be able to escape and may become trapped in the media. Air that may accumulate in the filter medium may form pressurized pockets that cannot be penetrated by the water, thereby potentially causing a reduction in effective medium volume used to entrap solids. This may in turn cause premature backwash.
  • air may be purged from the synthetic compressible media filter design by creating an upward water flow.
  • such upward water flow may be at five (5) to ten (10) gpm/ft 2 for two (2) to five (5) minutes.
  • the water flow rate and/or duration may be based at least in part on the medium thickness.
  • the third sequence of backwashing may comprise medium compression.
  • Medium compression may be achieved by, for example, creating a transition between the backwash and filtration.
  • the water level may be at its maximum, at which point an effluent control valve may be opened for a predefined duration (time delay set point), thereby causing the water to drain out of the filter.
  • time delay set point a predefined duration
  • both water and media velocities may increase.
  • higher friction forces between the media and the filter wall compared to the water head loss in the filter may cause the water velocity to exceed the media velocity. Therefore, the water level may drop exposing the media to air.
  • the filter influent flow may be started, using a time delay set point when the water level is still above the media level.
  • medium compression may be achieved by variable water flow and/or constant water flow.
  • the influent flow rate may be increased for a first period of time (for example, for a minute or two) in order to obtain a faster media compression and eliminate or reduce the need for water to waste sequence.
  • a first period of time for example, for a minute or two
  • the water to waste sequence duration may be defined based at least in part on filter turbidity observation.
  • PLC programmable logic control
  • an effluent flow control valve may be used to maintain an effluent flow rate equal (or substantially equal) to an influent flow rate.
  • the effluent valve may be partially opened to create head as necessary to equalize (or substantially equalize) effluent flow to influence flow.
  • the solids may accumulate in the medium, the solids may cause additional head loss, which in turn may cause the effluent flow rate to decrease.
  • the PLC may register this decrease in flow rate, and may open the effluent valve to balance out the head loss across the filter medium. In general, this may result in maintaining the effluent flow rate the same or similar to the influent flow rate - as well as maintaining the water level above the medium.
  • the new synthetic compressible media filter design is capable of an extreme filtration rate up to 40 gpm/ft 2 or 97.8 m 3 /h/m 2 while producing effluent with TSS ⁇ 5 mg/L and turbidity ⁇ 2 NTU, thereby satisfying current Title 22 discharge requirements.
  • the specific embodiments of the present invention shown and described herein are exemplary only.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Filtration Of Liquid (AREA)

Abstract

L'invention concerne également des procédés de fourniture de procédés de lavage à contre-courant pour un système de milieu filtrant compressible synthétique. Plus spécifiquement, le système peut comprendre une pompe de lavage à contre-courant et une soufflante d'air, et les procédés peuvent comprendre au moins trois séquences : de lavage à l'air et à l'eau; de la purge d'air; et de la compression du milieu. Le procédé de lavage à contre-courant peut être déclenché par un ou plusieurs points de consigne parmi une pression, un point dans le temps et/ou une turbidité. La séquence de lavage à l'air et à l'eau peut comprendre la rupture et le lavage du milieu. La séquence de purge d'air peut comprendre l'élimination de pratiquement la totalité de l'air piégé dans le milieu en fournissant un écoulement d'eau de lavage à contre-courant pendant une période de temps; et une séquence de compression de milieu qui comprime le milieu tout en évitant l'exposition du milieu à de l'air, y compris l'introduction d'eau brute et où le lavage à contre-courant et l'eau brute fournissent suffisamment d'énergie pour comprimer le milieu sans introduction d'air dans le milieu.
PCT/IB2016/001756 2015-11-04 2016-11-04 Procédés de lavage à contre-courant de milieu filtrant compressible synthétique WO2018083514A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA3003591A CA3003591A1 (fr) 2015-11-04 2016-11-04 Procedes de lavage a contre-courant de filtre compressible synthetique
CN201680064833.1A CN108348823B (zh) 2015-11-04 2016-11-04 合成可压缩介质过滤反洗过程
AU2016428792A AU2016428792B2 (en) 2015-11-04 2016-11-04 Synthetic compressible medium filter backwash processes
EP16836083.2A EP3365088A1 (fr) 2015-11-04 2016-11-04 Procédés de lavage à contre-courant de milieu filtrant compressible synthétique
AU2019271953A AU2019271953A1 (en) 2015-11-04 2019-11-27 Synthetic compressible medium filter backwash processes

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US62/250,771 2015-11-04
US201662250771P 2016-11-04 2016-11-04

Publications (1)

Publication Number Publication Date
WO2018083514A1 true WO2018083514A1 (fr) 2018-05-11

Family

ID=58016735

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2016/001756 WO2018083514A1 (fr) 2015-11-04 2016-11-04 Procédés de lavage à contre-courant de milieu filtrant compressible synthétique

Country Status (1)

Country Link
WO (1) WO2018083514A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003024560A2 (fr) * 2001-08-30 2003-03-27 Oase Wübker GmbH & Co. KG Dispositif de filtrage pour plan d'eau de jardin ou analogue
US20030111431A1 (en) * 1996-12-10 2003-06-19 Schreiber Corporation High rate filtration system
WO2004067136A2 (fr) * 2003-01-29 2004-08-12 Wwetco, Llc Appareil et procede de filtrage de fluides

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030111431A1 (en) * 1996-12-10 2003-06-19 Schreiber Corporation High rate filtration system
WO2003024560A2 (fr) * 2001-08-30 2003-03-27 Oase Wübker GmbH & Co. KG Dispositif de filtrage pour plan d'eau de jardin ou analogue
WO2004067136A2 (fr) * 2003-01-29 2004-08-12 Wwetco, Llc Appareil et procede de filtrage de fluides

Similar Documents

Publication Publication Date Title
AU2019271953A1 (en) Synthetic compressible medium filter backwash processes
KR101757211B1 (ko) 침전 및 여과 기능이 병행되는 수처리 장치
NO346912B1 (no) Vannbehandlingsfremgangsmåter
Ljunggren Micro screening in wastewater treatment-an overview
KR101446273B1 (ko) 수두차를 이용한 상향류 모래 여과장치의 운영 방법 및 이를 이용한 수처리 방법
CN103768857A (zh) 一种污水过滤器
KR101126049B1 (ko) 전처리 및 배출수 처리가 효율적인 상수 및 하폐수 처리용 막여과 시스템
JP3652567B2 (ja) ろ過装置の洗浄方法
WO2018083514A1 (fr) Procédés de lavage à contre-courant de milieu filtrant compressible synthétique
JP5102913B2 (ja) 膜濾過の逆洗排水を濃縮する装置および方法
US20100072118A1 (en) Low operating head polishing sand filter
KR101543548B1 (ko) 중력식 여과장치 및 이를 이용한 총인여과방법
CN103566764A (zh) 一种道路清洗扫路车的回收污水循环再生利用装置及方法
JP4592390B2 (ja) 高圧力式細砂ろ過装置
US20020023869A1 (en) Apparatus for the purification of liquids
KR101269582B1 (ko) 액상화 현상을 이용한 모래 여과 장치 및 방법
CN113371824B (zh) 一种弹性填料脱膜处理方法及水处理脱膜设备
JPWO2018047453A1 (ja) ろ過装置
KR101387606B1 (ko) 유지관리가 간편한 수처리용 상향류 여과조
JP2000511823A (ja) 高速濾過システム
Ødegaard et al. Enhanced primary treatment in floating filters
JP2014184375A (ja) 自然平衡型ろ過装置の洗浄方法
JP2003299915A (ja) ろ過装置及びろ過方法
CN104030465A (zh) 一种油水分离系统
CN203269707U (zh) 一种全自动高效节能曝气滤机

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 3003591

Country of ref document: CA

ENP Entry into the national phase

Ref document number: 2016428792

Country of ref document: AU

Date of ref document: 20161104

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE