CN100525891C - Water filtration using immersed membranes - Google Patents

Abstract

A process and apparatus is described for filtering water with immersed membranes. In a batch process, permeate is withdrawn while the flow of feed is reduced or stopped at the end of a permeation cycle. The water level is reduced to a level where a portion of the membranes are exposed to air before draining the tank. In this or another process, the level of liquid is reduced to correspond with an area of the membrane fibers having an accumulation of solids. Aeration is provided for a period of time with the liquid at this level to dislodge at least a portion of the solids from the membranes. In these or other processes, the tank is partially drained between cycles to deconcentrate the tank, aeration is provided during backwashing and intermittently while permeating, and/or retentate is withdrawn from the tank during a portion of a permeation step.

Description

Adopt the water filtration of immersed membranes

Technical field

The present invention relates to adopt the water filtration of immersed membranes.

Background technology

Below to the description of background of the present invention be not approval any information described herein any country all quotability as the part of prior art or those of ordinary skills' common practise.

Immersed membranes is to can be immersed in the liquid that remains under the environmental pressure during permeating, for example the filter membrane in the water.Water that has filtered or penetrating fluid are extracted the permeate side that arrives film by film by the fluid head that applies supply of transmembrane pressure reduction or film or stagnant liquid side, wherein transmembrane pressure reduction produces by the swabbing action or the siphonage of pump, and certain depth produces fluid head in the liquid by film is immersed in.A plurality of films are converged into the various unit that for example can be called as module or case usually.Film can be multiple structure, for example flat board or doughnut.In U.S. Patent No. 5,192, the example of flat sheet membrane unit has been described in 456.In U.S. Patent No. 5,639, the example of doughnut film unit has been described in 373, No.6,790,360, No.6,555,005 and No.6,325,928.

In water filtration, film is used for supply moisture is become permeate flow and stagnant liquid stream.Exemplary application comprises filtering underground or surface water supplying drinking water, and filters waste water that factory flows out to improve its quality before discharging.Although certain biologically active may occur in supplying with water, the biological treatment of supplying with water is not the main focus of wastewater treatment.Supply water in water filtration is tending towards having lower solids content than the supply water that is used for wastewater treatment.For example, the scope of total suspended solids content of supplying with water is at 0.005g/L or still less arrive about 0.1g/L.Flocculation or other chemistry or Biological Pretreatment can be used for improving the filterability of supplying with water and can cause having up to the about solids content (TSS) of 0.2g/L from the supply glassware for drinking water that the flocculation jar flows to the film jar.Some preliminary treatment are unsuitable for being used in the following division technique: wherein periodically the water of jar is drained fully, reason is that chemicals just had been wasted before they use fully or because the concentration of chemical agent must remain in the narrower scope.

In U.S. Patent No. 6,156, an example of water filtration process has been described in 200.In this technology,, be back scrubbing and air douche step after per 30 minutes suction time section for canful.After every 3-10 suction period, jar is just drained fully and is filled once more.

In U.S. Patent No. 6,303, other examples of water filtration process have been described in 035.In a technology, filtration cycle may further comprise the steps: jar is filled into water level more than the film, penetrating fluid is extracted by the water level of film in simultaneously jar on film; Ventilation is carried out draining to jar simultaneously with solid and the back scrubbing film that removes on the striping to film then.

Another example of water filtration process has been described in the open WO01/36075 of international monopoly.Film module is arranged to cover basically the cross section of jar.Filtration cycle has immediately following the impregnation step that dilution step is arranged.During permeating, supply with the penetrating fluid that water is substantially equal to remove.During diluting, utilize ventilation that the flushing bubble carries out to supply with in the water one or two and carry out from the module below with back scrubbing and supply.Water upwards flows through module substantially and flows out from the overflow area of tank top in the unnecessary jar.

In U.S. Patent No. 6,375, other illustrative processes has been described in 848.A technology is carried out in the mode of the circulation of a plurality of repetitions.This circulation is immersed in jar interior water with film and begins.Penetrating fluid is pumped through film, and simultaneously the flow of removing with the penetrating fluid water of increasing supply is dipped into to keep film.After 2 to 5 hours infiltration, the flow that current were opened and supplied with to the draining valve in jar correspondingly improves keeping film to be dipped into, and infiltration is proceeded.Draining valve was opened 25 minutes, and 100% to 300% water of tank volume is discharged.When the solid concentration of water in the jar reduced at least 60%, drain shut valve and new circulation began.In another technology that same invention is described, film module is immersed in the jar.Supplying with water enters in the jar continuously to keep film to be dipped into.Except the time period of film back scrubbing, penetrating fluid passes module and flows out continuously from jar.The interior water of jar flows out continuously from jar by draining but its flow only is to supply with 20% of discharge.Film is ventilated continuously to clean the water in film and the blending tank.

Can be by one or more performances of measuring water filtering system in the various parameters that depend on concrete application.An admissible parameter is the rate of recovery, and it refers to the ratio of the penetrating fluid that supplies the water supply point generation of per unit volume.The rate of recovery is high more, and the volume of the stagnant liquid that then must be discharged or further handle is low more.Admissible another parameter is the cost of energy of ventilation.Many immersed membranes system's use ventilations or air douche are to prevent film incrustation.Be an important annual charge and be the major part of film cost system life cycle to the required energy of film unit ventilation.Admissible another parameter is the scale rate of film.The speed of film incrustation influences the time that film unit continued and keeps this unit to operate in Chemical cleaning required under acceptable permeability or the flow or ventilation effect before it need be replaced.Film incrustation is relevant with many factors, comprises ventilation and the validity of back scrubbing and the solid concentration of film supply side or stagnant liquid side.Water filtering system according to the one or more operational excellences in these parameters need be provided.

Summary of the invention

An object of the present invention is prior art is improved, or provide a kind of useful alternative to prior art at least.Another object of the present invention provides a kind of technology or device that uses water with immersed membranes to filter.This technology or device improve one or more in the rate of recovery, aeration energy cost or the film scale rate.Following summary is to introduce the present invention to the reader, rather than will limit the present invention, because can also be to this part or the other parts of present specification, and the described device element of claim or processing step makes up or modification for example.

On the one hand, thus the present invention relates to a kind of being used for carries out the method that back scrubbing reduces the volume of the water that each back scrubbing or dilution discharge to immersed membranes.For immersed membranes system, under by the situation that the draining of film jar is periodically discharged water, between the filtration cycle time (giving the time between jar draining incident) and the water volume of being discharged, there is a kind of relation with batch mode operation.

$t_F=V_{\mathrm{BW}}\×\frac{R}{Q_F(1-R)}$

Wherein:

t _F=filtration cycle the time

V _BWThe volume of=the water that discharged

Q _FThe clean filtering traffic of=(on average)

The R=rate of recovery (filtrate/supply water)

Volume by the water that will be discharged is reduced to minimum, can reduce the filtration cycle time, keeps identical system recoveries rate simultaneously.The shorter filtration cycle time causes film properties to improve (because if new circulation begins with water in the jar of high dilution, then film operates in the lower water of average solids concentration) by reducing film incrustation, and therefore makes the film system with higher flux design and running.Alternatively, the reduction of the water volume of being discharged makes the film system with higher system recoveries rate operation, and does not influence filtration cycle time and film properties.Though jar can between two circulations, be emptied completely, the volume that the water volume of being discharged also can be equal to or less than jar, and can by before giving jar draining, make permeate flow get back to jar in and film is carried out back scrubbing.

On the other hand, the present invention relates to a kind ofly have in back scrubbing or the membrane filtration process in batches of the penetrating fluid decline step before giving jar drain step.This technology is permeated then from jar is filled, and the water of increasing supply simultaneously is to remain in jar constant water level of cardinal principle of inner membrance top.After this step, the water level in the film jar drops to the water level of reduction in penetrating fluid decline step, and penetrating fluid decline step comprises and reduces or stop the film jar is supplied water but proceed infiltration, to reduce the water level in the film jar.A water level even the part that can be reduced to film are exposed to airborne degree.Then the film system is carried out back scrubbing with from fenestra and from film surface removal solid.Selectively, the water level that reduces in the film jar can perhaps make the part of film keep being exposed in the air so that backward erosion is immersed membrane fiber fully once more.After back scrubbing, can give the draining of film jar.Alternatively, before being carried out draining, can use by jar the second penetrating fluid decline step to reduce water level once more.Can before or after descending, water level carry out back scrubbing to film.Utilize or do not utilize the second penetrating fluid decline step, the part of film can be exposed in the air when beginning for a jar draining.Membrane fiber can also penetrating fluid descend step or a plurality of penetrating fluid decline step, backwash step, give one or more in jar drain step during or before the arbitrary steps in these steps or between carry out air douche.In these steps some can also overlap with other step.

On the other hand, the present invention relates to a kind ofly be used to improve ventilation efficiency in case the technology of film incrustation.The inventor observes, although conventional back scrubbing, ventilation or Chemical cleaning are arranged, solid or mud still may accumulate in around the membrane fiber.Especially, mud may be deposited in one deck of lower collector pipe top of vertical fibers module, in one deck of upper header below or other zone that under common air douche, is difficult to contact of the module of these or other type with bubble.Being used to reduce mud accumulates in and is immersed in the technology on the membrane fiber in the liquid and comprises the liquid water position is reduced near having zone that mud gathers or its of film, and the air douche of a period of time is provided when liquid level is positioned at this water level place, to get on except that mud or solid from membrane fiber.Although the present invention is not limited to this theory, the inventor believes that mud or solid that the energy that bubble discharged that bursts at the water surface place that reduces can be removed in the problem area of module very effectively pile up.Mud can perhaps be removed a little later by thereafter the surplus water of jar being drained and directly removing from the film jar, for example removes after jar is filled once more.

On the other hand, provide a kind of possibility with to film unit, the element of the vertical centering control hollow fiber that particularly extends between upper header and lower collector pipe or extend downwards from single collector is ventilated.Film unit is filled under the top of unit or the situation above it at jar usually and ventilates.As an alternative, jar water level be reduced near a certain water level, this water level flows through below other structure of unit vertically upward at upper header or restriction, for example the upper header bottom is following 1 centimetre to 10 centimetres or 2 centimetres to 6 centimetres, simultaneously to described element ventilation.Help to prevent destruction like this to film, described destruction might be since in the bubbles strike upper header bottom of rising and the energy dissipation that is displaced sideways when from module, overflowing produced.But the energy that the surperficial place of water discharges in jar also can clean the upper area of film.

In certain embodiments, above-described technology and filtration system, the operating procedure that for example has a system of infiltration and dilution circulation combines.

In others, the invention provides multiple other filtering technique.These filtering techniques for example can be used in the new equipment or as existing equipment, for example have the supply of continuous ventilation and the improvement of exhaust apparatus.After improvement had the existing supply and exhaust apparatus of continuous ventilation, this technology can reduce required throughput to finish described variation with the acceptable cost.For example, existing supply and exhaust apparatus can not discharge the water of large volume apace.Therefore, the cost that this equipment is transformed into when infiltration stops the jar emptying is expensive.Even in newly-built equipment, the whole volume with jar between impregnation step emits the cost that also can increase equipment, and can hinder or stop some required preprocess methods of use.Therefore, described technology is not with the jar emptying between impregnation step.

On the one hand, the invention provides a kind of circulation technology, wherein after the time of penetration section of leaving seldom or without any stagnant liquid jar, film is reversed and washes away and ventilate.After backward erosion, the part of the jar of draining, for example water of Guan about 10%-25%.During this partial drainage, ventilate and can proceed, and because the major part of film, for example 75% or more most of maintenance immerse and remain valid.At doughnut vertically under the situation of location, the bottom of module is incrustation and can not realize ventilation to this part module by partial drainage quickly.After partial drainage, to jar fill once more and begin next the circulation in infiltration.

On the other hand, the invention provides a kind of technology with continuous substantially trash discharge.Infiltration also is continuous substantially, but for example can periodically stop for back scrubbing.During this back scrubbing and between twice back scrubbing, ventilate off and on.Compare with continuous ventilation technology, ventilation has reduced employed air capacity off and on.

On the other hand, the invention provides a kind of continuous substantially circulation technology that except being used for periodic back scrubbing, permeates.Ventilating during the back scrubbing and ventilating and after back scrubbing, to continue for some time.The stagnant liquid that flows out from jar is provided during back scrubbing and can continues to surpass back scrubbing and aeration step, for example 1/4th of circulating continuancing time or 1/3rd, but less than the whole circulation duration, for example 2/3rds of circulating continuancing time or 1/2nd or still less.The time period that is dispersed in jar interior water with the solid that discharges from film by ventilation and back scrubbing the opportunity that stagnant liquid flows and more likely removes with higher concentration in stagnant liquid stream is consistent.The stagnant liquid volume of removing in each circulation provides the desired rate of recovery and can be littler than tank volume, for example less than tank volume 50% or between the 5%-30% or 5%-20% of tank volume.

By above-described any technology, the filtration cycle time can be 45 or 40 minutes or still less, 30 minutes or still less or 20 minutes or still less.The rate of recovery can be 80% at least or be 90% or between 90% to 95% at least.Filtering traffic is the function of membrane flux and surface area.Membrane flux can be 40L/m ²/ h or bigger or 50L/m ²/ h or bigger or 60L/m ²/ h or bigger.For the tank volume of every mao of cubic meter, the film surface area can be 250m ²Or 350m ²Or bigger, perhaps 750m ²Or still less.Tank volume is measured with a benchmark or design water level, described benchmark or design water level can be jar just be full of and jar in water approximately be in the water level at film unit top.The water yield of extracting as penetrating fluid can be per hour 5 times to 70 times to tank volume or per hour 6 times to 40 times to tank volume.The required time of penetrating fluid that the jar holdup time one is shifted out a tank volume, can be between 1.5 minutes to 10 minutes, perhaps for the technology of filtering medium or highly filled supply water between 5 minutes to 10 minutes, perhaps for the technology of the supply water that filters low or medium solids content between 1.5 to 7.5 minutes.This technology can be non-recirculation.The amount of the penetrating fluid in back scrubbing technology, entering once more jar can tank volume 10% to 40% or 50% between, perhaps tank volume 20% to 30% between.For the technology Calculation that comprises tank volume, for example with respect to tank volume, the calculating relevant with the volume of backwash water stagnant liquid of removing or penetrating fluid or that return, jar holdup time and relevant calculating, the occupied volume of film unit self deducts from total tank volume.The amount of circulation timei, the penetrating fluid amount of removing and the stagnant liquid removed be correlated with and can be selected to obtain the required rate of recovery.

On the other hand, the present invention relates to a kind of technology of during jar is carried out filling step, film unit being ventilated.

In others, the invention provides the above-mentioned all possible combination in any two or more aspects.From following to exemplary embodiment explanation or claim can recognize others of the present invention.

Description of drawings

Referring now to accompanying drawing embodiments of the invention are described.

Fig. 1 is the schematic diagram of filter.

Fig. 2,3 and 4 expresses multiple film case.

Fig. 5 is the flow chart of technology according to an embodiment of the invention.

The side view and the plane of Fig. 6 and 7 another devices of expression.

Fig. 8 is the flow chart of another technology according to an embodiment of the invention;

Fig. 9 is the flow chart of another technology according to another embodiment of the present invention;

Figure 10 is the schematic diagram that the film jar begins to locate in technology shown in Figure 8;

Figure 11 is the schematic diagram that film jar shown in Figure 10 is in the subsequent step place of technology shown in Figure 8; And

Figure 12 is the schematic diagram that the film jar is in a step place of technology shown in Figure 9.

Figure 13,14 and 15 is schematic diagrames of technology according to other embodiments of the present invention.

The specific embodiment

Hereinafter film unit, filter element and total supply in batches and the describe, in general terms of discharge technology are applicable to other embodiment that further describes below, although the description of this describe, in general terms and any specific embodiment is all inconsistent.

To Fig. 4, show reactor 10 referring now to Fig. 1, it is used for the supply liquid with solid is handled, with the penetrating fluid that has filtered of generation solid concentration reduction and the stagnant liquid of solid concentration raising.This reactor 10 has many potential application and can for example be used for forming from the water source such as lake, well or reservoir drinkable, municipal administration or the inhabitation water, is used for the triple filter of waste water, perhaps is used to filter water for industrial use.Whether this supply water comprises colloid, suspended solid, bacterium and other particle or material usually, and they must be filtered, and be the solid-state solid that all totally is called.Reactor 10 can change in every way, and comprising provides pretreatment stage or post-processing stages.Following description is used to introduce to be used example system of the present invention rather than the present invention will be defined in specific reactor.

First reactor 10 comprises pending supply water 14 16 18 is pumped into jars 20 feed pump 12 by entering the mouth from the water source, supply with water in jar 20, become jar in water 22.Alternatively, also can use gravity feed, wherein replace feed pump 12 with water-supply valve.Each film 24 have do not contact with water 22 in the jar and since its in the inboard and sightless permeate side of film 24, and the stagnant liquid side that contacts with water 22 in the jar.Film 24 can be a hollow-fibre membrane 24, is that the inner chamber of stagnant liquid side and film 24 is permeate side for the outer surface of hollow-fibre membrane 24.

Film 24 connects into element 8.Shown element 8 is examples of spendable a kind of film unit, and however, the present invention also can use other film unit.In element 8, each film 24 is connected on one or more collectors 26.Each collector 26 is the closing end or the closed circuit of film 24 fixedly, perhaps the fixing openend of film 24 and help the openend of film 24 is connected on the permeate collection passage.The openend of film 24 by encapsulating material around, between the outside of film 24 and collector 26, to form watertight connection, keep the permeate side of film 24 to be communicated with simultaneously with permeate passageway fluid at least one collector 26.The permeate passageway of collector 26 is connected with infiltration liquid pump 32 with permeate collection device 30 by penetrating fluid valve 34.The air of taking away in the permeate flow by permeate collection device 30 is collected in the air collector 70, and air collector 70 is usually located on the local high spot at least in the permeate collection device 30.Air collector 70 is by gas collection valve 72 evacuation of air or have pump discharging air periodically, and gas collection valve 72 can for example be opened when film 24 back scrubbing with to the airborne release air.Export 38 places by outlet valve 39 at penetrating fluid and produce the operational penetrating fluid that has filtered 36.Storage pot valve 64 can periodically be opened so that penetrating fluid 36 can enter storage tank 62.The penetrating fluid 36 that has filtered is needing post processing as before the drinking water, but should have acceptable colloid and other suspended solids content.

In large-scale reactor 10, a plurality of elements 8 can fit together and form case 28, and case 28 can be joined together to form other bigger film unit.A plurality of permeate collection devices 30, infiltration liquid pump 32 or other parts can be arranged.In Fig. 2,3 and 4, schematically shown the example of case 28.Each element 8 of shown type can have a branch of or multi beam 1cm to the wide hollow-fibre membrane 24 of 10cm.Also can use element 8 and case 28 or other film unit of other type.Film 24 can have the average pore size of micro-filtration or ultrafiltration scope, for example between 0.003 micron to 10 microns or between 0.02 micron to 1 micron.Element 8 also can only have an infiltration collector tube 26, in this case, does not lead to the phreatic line of other collector tube 26.Collector tube 26 can also have opening so that water or air can flow through collector tube 26.

With reference to Fig. 3, for example, a plurality of elements 8 are connected on the shared permeate collection device 30.Film 24 is positioned on the perpendicular vertically.According to the degree of depth of the length of film 24 and jars 20, a plurality of casees 28 shown in Figure 3 can also one overlay on another.With reference to Fig. 2 and 4, element 8 is illustrated and is in optional orientation.In Fig. 2, film 24 is positioned in the horizontal plane, and permeate collection device 30 is connected on a plurality of elements 8 that overlay on another.In Fig. 4, film 24 flatly is positioned in the perpendicular.According to the degree of depth of collector tube among Fig. 4 26, permeate collection device 30 also can be connected on these a plurality of casees 28 that overlay on another.For the sake of clarity, the case 28 of expression has been simplified in Fig. 2,3 and 4, the framework that actual case 28 has more close together element 8, more element 8 usually and they are fixed together.

Case 28 or other film unit can be by having difformity, for example columniform element 8 and be connected on the single collector tube 26 the lopping fibre bundle or an end is fixed on the collector 26 and other end loose fibres bundle forms.Similarly module, unit or case 28 also can substitute hollow-fibre membrane 24 formation with tubular film.For flat sheet membrane 24, paired film 24 can connect with form closure surfaces between the film and make suitable pipeline can with collector or housing that the inside of closure surfaces links to each other on.Several in these unit can be joined together to form the flat sheet membrane case.Commercially available hollow-fibre membrane case 28 comprises the case of being made and being sold with trade mark ZEE WEED by ZENON Environmental Inc., for example ZEE WEED500 or ZEE WEED1000 product.

For Chemical cleaning is provided every now and then, in chemicals jar 68, is provided with to clean and uses chemicals, for example clorox, NaOH or citric acid.When chemical back wash valve 66 was opened, penetrating fluid valve 34, outlet valve 39 and back wash valve 60 were all closed.Chemical pump 67 operation with promote to clean with chemicals passed through chemical backwash pipe 69 and then the negative side by the wall of permeate collection device 30 and film 24.When Chemical cleaning finished, chemical pump 67 disconnects and chemical pump 66 is closed.Preferably, closelying follow after the Chemical cleaning has the penetrating fluid back scrubbing, with the cleaning chemicals of clean permeate gatherer 30 before recovering in infiltration and film 24.Chemical cleaning can also be by filling jar 20 and the solution suction being undertaken by film 24 with chemical solutions.

In order to fill jars 20, feed pump 12 will be supplied with water 14 and 16 18 be pumped into jars 20 by entering the mouth from the water source, supply with water water 22 in jar 20 places become jar.When the water level of water in the jar 20 covers film 24 in jars 20 first fully, even if jars 20 full, but jars 20 also can other the time have be in this more than water level jar in water 22, and may operate under the situation that is positioned at the design water level on the full-water level.

In order to permeate, penetrating fluid valve 34 and outlet valve 39 are opened, and infiltration liquid pump 32 is opened.With respect on the permeate side of film 24, forming negative pressure around water 22 in the jar of film 24.Resulting transmembrane pressure can be at 1kPa between the 100kPa, perhaps at 20kPa between the 85kPa, by film 24 (then being called as penetrating fluid 36), film 24 filterings simultaneously are retained in the interior solid of jar interior water 22 to this pressure with 22 suctions of water in the jar.Therefore, export 38 places at penetrating fluid and produce the operational penetrating fluid that has filtered 36.Storage pot valve 64 is periodically opened and is made penetrating fluid 36 enter storage tank 62 to use in back scrubbing.When the penetrating fluid 36 that has filtered is removed from jar, during part time of penetration or whole time of penetration, feed pump 12 can move water in the jar 22 is remained on the water level place of coverlay 24, for example Guan full-water level or design water level, thereby solve the problem of removing stagnant liquid (if any) during permeating, perhaps remove the problem of foam (if existence) or other material (if existence).

For back scrubbing (being called backward erosion or back flush alternatively) film, when infiltration stopped, backwashings valve 60 and storage pot valve 64 were opened.Infiltration liquid pump 32 is opened with the penetrating fluid 36 that will filter and is promoted by backwash pipe 63 up to collector tube 26 and oppositely by the wall of film 24 from storage tank 62, removes some thus and is connected solid on the film 24.In back scrubbing, the volume of pumping by the water of the wall of one group of film 24 can be keep film 24 jar 20 volume 10% to 40% between, more frequent is between 20% to 30%.When back scrubbing finished, back wash valve 60 was closed.As adopting infiltration liquid pump 32 to drive the optional mode of back scrubbing, also can be at the other pump that separation is set in the backwashings pipeline 63 that permeates liquid pump 32 of crossing then.By means of arbitrary device, back scrubbing can continue 15 seconds to 1 minute.When back scrubbing finished, infiltration liquid pump 32 disconnects then and back wash valve 60 is closed.Flow during the back scrubbing can be permeate flow 1-3 doubly, and can with continuously, intermittently or impulse form provide.

For flushing out air (being called ventilation alternatively) is provided, air feed pump 50 open and from air inlet 52 by air distribution 54 with air, nitrogen or other suitable gas be blown into below membrane component 8 or the case 28, between or with the breather 56 of their one, and bubble 58 is distributed in jar interior water 22 the bubble film 24 of upwards flowing through.

The amount of the flushing out air that is provided depends on a plurality of factors, but preferably relevant with the superficial velocity of the air-flow that passes through breather 56.The superficial velocity of air-flow is defined as under standard state air flow rate that (1 atmospheric pressure and 25 degree Celsius temperatures) flow to breather 56 divided by by the effective cross-sectional areas of flushing of breather 56.Can provide flushing out air by operation air feed pump 50, with produce and superficial velocity at 0.005m/s to the corresponding air of the air-flow between the 0.15m/s.When the air douche step finished, air feed pump 50 disconnected.Although air douche is the most effective during water 22 in film 24 is immersed in jar fully, it is still useful when the part of film 24 is exposed in the air.Air douche is more effective when combining with back scrubbing.

Sometimes also can provide air douche with the solid dispersed in the water 22 near the jar the film 24.This air douche prevents from excessively to contain solid near water 22 in the jar of film 24 when penetrating fluid extracts by film 24.For this air douche, can air be provided continuously or provide air off and on to the air-flow superficial velocity between the 0.15m/s to the air-flow superficial velocity between the 0.015m/s with 0.005m/s, provide 5-180 second or every 1-4 minute that 5-20 is provided second in for example every 1-15 minute with 0.005m/s.

Water 22-jar speed of interior water 22 and degree can be called draining, filtering, waste liquid is removed or discharging according to removing for this in order to remove from jar 20 in unfiltered jar, and draining valve 40 is opened so that include the solid that concentration improves and the interior water 22 of jar that is called as stagnant liquid 46 then and export 42 from jar 20 by stagnant liquid and flow to drainpipe 44 or other treatment region.Be detained liquid pump 48 and can open giving a jar draining quickly, but in many equipment, jar only by the just enough fast evacuation of gravity, particularly during permeating, need under the situation of discharging of waste liquid.May spend 2 to 10 minutes jars 20 to drain fully, and jar 20 be carried out partly draining with the less time full state.Can also be by from jar 20, removing stagnant liquid 46 from jar 20 top overflows or by pipeline or other conduit at intermediate altitude.

In general filtering technique, water 22 can recycle with other jar or cistern in jar.Alternatively, all enter jars 20 supply water 14 and can leave jars 20 as penetrating fluid 36 or stagnant liquid 46 basically, and stagnant liquid 46 does not turn back in jars 20.In order to realize the application's purpose, wherein by in batches, supply with and discharging or another technology, all enter jars 20 supply water 14 all as penetrating fluid 36 or can not get back to jars 20 stagnant liquid 46 and leave these technologies of jars 20 and be called as non-recirculating process basically.If stagnant liquid 46 no longer further filters, then non-recirculating process also can be called as one way technology.If stagnant liquid 46 filters in the reactor in downstream once more, but still do not turn back in the jar 20, then this technology also can be called as first journey of multipass system.The major part of water 22 removes and flow back into water source 16 in wherein unfiltered jar from jar 20, or gets back to jars 20 technology by some other passages that have water 22 in some or all jars that are removed and be called as recirculating process.All embodiment hereinafter described are non-recirculating process, unless otherwise stated.But each side of the present invention also goes for recirculating process, particularly supplies with those technologies of water 22 recirculation between the similar water source 16 of jar 20 and volume.In technology, the time period that supply water 14 enters jar 20 and only has penetrating fluid 36 to leave jar 20 can be called as dead-end filtration (the dead end filtration) time period.Technology with dead-end filtration time period can be called as dead end technology, though in section At All Other Times, for example in the dilution time section, stagnant liquid 46 also can leave jars 20.For the application's purpose, have the main time period of extracting penetrating fluid 36 but not extracting stagnant liquid 46 and extract stagnant liquid 46 but the circulation technology that do not extract another short period section of penetrating fluid 36 can be called as in batches or discontinuous technology.In the time period of extracting penetrating fluid 36, if not purpose, dead-end filtration or recirculation infiltration can be arranged for the application, batch process is assumed to be to have dead end time of penetration section, unless otherwise stated.

An example of non-recirculation batch filtration technology can have concentrating or infiltration and dilution step of repetitive cycling.In concentration step, penetrating fluid extracts the water 22 in a collection of new jar that has low solid concentration at first.For example, if jars 20 drained fully and filled once more, then jar in water 22 initially have the solid concentration identical with supply water 14.When extracting penetrating fluid, new supply water 14 is introduced into, and is used as the water that penetrating fluid 36 extracts with replacement.During may continuing this step of 10 minutes to 4 hours or 15 minutes to 40 minutes or 45 minutes, solid tunicle 24 filterings and can from jar 20, not flowing out with penetrating fluid 36.In one way technology, remove the recirculation of flowing of thing or jar interior water 22 without any stagnant liquid 46 or other.The concentration of solid is brought up to 2 to 100 times or 5 to 50 times of the concentration of for example supplying with water 14 as a result, jar.This technology enters dilution step then.In the duration is that water 22 is removed a large amount of solids fast in unfiltered jar from jar 20 by removing, thereby makes solid concentration get back to initial concentration in 1/50 to 1/5 the dilution step of duration of concentration step.This can realize by jars 20 a part of water and it is recharged with new supply water 14 of draining.In order to help solid oneself to leave film 24, can before the dilution step or during use air douche and back scrubbing.The common dilution step in front of new circulation begins when finishing.But, when some circulates in new reactor 10 and puts into operation first or after Chemical cleaning or other maintenance practices, begin.

Optionally technology is supply and the discharging or the continuous processing of non-recirculation.In the example of supply and discharge technology, supply with water 14 and flow in the jar 20 continuously basically.Penetrating fluid 36 extracts basically continuously, but for example also can stop sometimes in order to carry out back scrubbing.Stagnant liquid 46 discharges from jar basically continuously, and in one way technology, can not turn back in the jar 20.The average discharge of stagnant liquid 46 can be the 1%-20% that supplies with the flow of water 14.Remaining supply water 14 can be used as penetrating fluid 36 and removes.Solid concentration in jar in the water 22 may high 5-20 level doubly to the concentration of supplying with water 14.During permeating, can ventilate continuously.

Referring now to Fig. 5, utilize the filtering technique of immersed membranes filtered water to have impregnation step 102, penetrating fluid decline step 104, backwash step 106, the air douche step 108 of filling step 100, balance and give a jar drain step 110.These steps have formed the circulation that repeats to implement to be used for continuous filtration.Each step will be described hereinafter in more detail.

In filling step 100, feed pump 12 will be supplied with water 14 and 16 18 be pumped into jars 20 by entering the mouth from the water source, supply with water water 22 in jar 20 places become jar.Even if jar 20 is filled when the water level of water in the jar 22 covers film 24 in jars 20 fully.

During the impregnation step 102 of balance, draining valve 40 keeps cutting out.Penetrating fluid valve 34 and outlet valve 39 are opened and are permeated liquid pump 32 and open.With respect to jar interior water 22, in the permeate side formation negative pressure of film 24 around film 24.By film 24 (then being called as penetrating fluid 36), the solid in jar interior water 22 is stayed in film 24 filterings simultaneously to resulting transmembrane pressure with 22 suctions of water in the jar.Therefore, export 38 places at penetrating fluid and produce the operational penetrating fluid that has filtered 36.Storage pot valve 64 can periodically be opened, and makes penetrating fluid 36 enter storage tank 62 to use in back scrubbing.When the penetrating fluid 36 that has filtered was removed from jar, feed pump 12 operations were to remain on water in the jar 22 on the water level of coverlay 24, and for example water level is filled in Guan full-water level or design.Foam or other material also can be removed aperiodically, but are dead-end filtration basically.The impregnation step 102 of balance can continue 15 minutes to 3 hours or between 15 minutes to 40 or 50 minutes or 45 minutes to 90 minutes.Especially, if the impregnation step of balance 102 continues 45 minutes or longer, ventilation or backwash step in the middle of then in the impregnation step 102 of balance, can having.During the impregnation step 102 of balance, film 24 can carry out ground back scrubbing or air douche frequently before the penetrating fluid decline step 104 of described technology or dilution step, and the impregnation step 102 of balance is during this intermediate air flushing or backwash procedure or continue afterwards to carry out.

In penetrating fluid decline step 104, infiltration liquid pump 32 continues operation, but feed pump 12 slows down or stops alternatively.Like this, produced penetrating fluid 36 but jar in the water level of water 22 reduce.Water 22 can be reduced to the top of the highest part of film 24 or the position that the part that is reduced to film 24 is exposed to air in jar.Structure according to film 24 or element 8, the part of film 24 is exposed to air may means jar water level of interior water 22 below some whole films 24 or element 8 but above other, perhaps jar in the water level of water 22 below the part of one or more films 24 or element 8 but above the other parts of same film 24 or element 8.The expose portion of film 24 also can be the whole of film 24, particularly under the situation that last film 24 can be isolated with infiltration liquid pump 30.

Reduce jar 20 interior water levels and can temporarily reduce maximum transmembrane operating pressure, and therefore can cause temporarily reducing of permeate flow in some cases.But the benefit that the filtration cycle time descends may surpass the temporary transient benefit that reduces of liquid stream.When the part of film 24 is exposed to air, permeate also and some air can be drawn in the penetrating fluid 36.These air are collected in the air collector 70 and discharging every now and then, and compare with amount of air drawn, and air collector 70 is enough big, and these air can not hinder the others of device or technology.But, for fear of excessive air is drawn into permeate collection device 70, during penetrating fluid decline step 104, transmembrane pressure can remain on below the bubbling point of the film 24 that does not have defective, and being exposed in the air area that links to each other with infiltration liquid pump 32 simultaneously and can being limited to and being no more than 50% of jars 20 interior total membrane areas of film 24.Be collected in the air capacity in the air collector 70 during the monitor permeate decline step 104.If collected within a certain period of time air capacity surpasses based on the reasonable amount by the wet hole diffusion, then be illustrated in and have defective and if necessary in the film 24, test and keep in repair film.

In order to finish penetrating fluid decline step 104, infiltration liquid pump 32 and feed pump 12 disconnect, and penetrating fluid valve 34 and outlet valve 39 are closed.Feed pump 12 (if in operation) can stop.

In backwash step 106, if no longer give jar 20 drainings then draining valve 40 cuts out, back wash valve 60 and storage pot valve 64 are opened.Infiltration liquid pump 32 is opened being advanced to collector 26 and the reverse wall by film 24 from the penetrating fluid 36 that will filter from storage tank 62 by backwash pipe 63, thereby gets rid of some solids that are connected on the film 24.In back scrubbing, the volume of pumping by the water of the wall of one group of film 24 can the volume of the jar 20 that keeps film 24 10% to 40% between, more frequent is between 20% to 30%.When back scrubbing finished, back wash valve 60 was closed.As using infiltration liquid pump 32 to drive the possibility of back scrubbing, can also by then, cross the pump that separation is set in the back scrubbing pipeline 63 that permeates liquid pump 32.By arbitrary device, back scrubbing can continue 15 seconds to 1 minute, and after this, backwash step 106 finishes.Infiltration liquid pump 32 disconnects then and back wash valve 60 is closed.

Flux during the back scrubbing can be 1-3 times of the penetrating fluid flux, and impels the water level of jar interior water 22 to rise.During the step 104 that penetrating fluid can be descended during the reduction of water level and the backwash step 106 rising of water level be arranged to and make that film 24 is immersed fully when backwash step 106 finishes.For example, for aeration step 108 subsequently, film 24 can be immersed fully.With the back scrubbing and compare for then the technology of jar draining after the infiltration of balance of film 24 wherein, reduced the volume of the interior water 22 of jar that discharge for thinning tank 20 like this.Alternatively, the reduction in penetrating fluid decline step 104 middle water level can make the part of film 24 keep being exposed to air when backwash step 106 finishes above the rising of backwash step 106 middle water levels.Further like this minimizing in volume and the employed time of giving the water that is discharged during jar drain step 110.But, can make the efficient of aeration step 108 lower, and therefore aeration step is moved on to or the impregnation step 102 that another aeration step 108 is added to balance finished after or between tailend, between the impregnation step 102 of balance and the penetrating fluid decline step 104 or in penetrating fluid decline step between elementary period, to comprise the time that film 24 is immersed fully.

In air douche step 108, by operation air feed pump 50 so that flushing out air to be provided, thereby from below element 8 or the case 28, between or with it the breather 56 of one produce and be equivalent to 0.005m/s to the bubble of the air-flow superficial velocity the 0.15m/s 2 minutes.The strong air douche of duration can wash film 24, so that solid is removed above them, and usually with the solid dispersed removed in the jar in the water 22.When air douche step 108 finished, air feed pump 50 disconnected.Although the air douche step is illustrated in after the backwash step 106, it also can be set at before the arbitrary steps among the step 104-110, during or between.Although air douche step 108 is the most effective in the water 22 time in film 24 is immersed in jar fully, it is still useful when the part of film 24 is exposed to air.Air douche step 108 be used in combination with back scrubbing fashionable more effective.For example, air douche step 108 can begin simultaneously basically with backwash step 106 and stop when backwash step 106 stops or after stopping.Like this, air douche carries out in back scrubbing, and this moment, air douche was the most effective for given water level.

For supply water 14, be exactly all required as the air douche of a dilution step part with minimum incrustation performance.But, supply with water for some with incrustation performance significantly, also can during the impregnation step 102 of balance or penetrating fluid decline step 104, mild air douche be set, with the solid in the water 22 near the jar the dispersion membrane 24.This mild air douche is used to prevent excessively contain solid near water 22 in the jar of film 24 when penetrating fluid extracts by film 24.Correspondingly, this air douche is not counted as the part of the air douche step 108 in the circulation shown in Figure 5.For mild air douche, can air be provided continuously or provide air off and on to the air-flow superficial velocity between the 0.15m/s to the air-flow superficial velocity between the 0.015m/s with 0.0005m/s with 0.005m/s.

In drain step 110, draining valve 40 open so that include the solid that concentration improves and in the jar that is called as stagnant liquid 46 water 22 flow to drainpipe 44 from jar 20 by stagnant liquid outlet 42.Be detained liquid pump 48 and can open giving a jar draining quickly, but in many equipment, only just can make a jar emptying fast enough by gravity.Drain step 110 can after step 104,106 and 108 all is finished to, begin or alternatively can be in step 104,106 or 108 part of ongoing while of arbitrary steps or film 24 begin when being exposed to air.In most of industry or municipal equipment, to spend 2 to 10 minutes usually jar 20 is emptied completely from full state, the time spent is then lacked when water level reduces.

In the optional embodiment of technology, implement or repeatedly implement with different order with reference to some steps shown in Figure 5 with penetrating fluid decline step 104.For example, after penetrating fluid decline step 104, can before backwash step 106, implement for a jar drain step 110.Can increase by second then and give a jar drain step 110 after backwash step 106, perhaps draining valve 40 stays open and makes and continue to carry out for a jar drain step 110 during backwash step 106.Backwash step 106 and can also carry out or partly carry out simultaneously for a jar drain step 110 basically simultaneously.In these methods, can be reduced 110 required total times of drain step for jar, although aeration step 108 need be reorientated, replenish or implement longlyer.

In other optional embodiment, after backwash step 106, can before giving jar drain step 110, implement the second penetrating fluid decline step 104.The volume of the water that is discharged during jar drain step is given in so further minimizing.Can or wholely implement the second penetrating fluid decline step 104 during giving jar drain step 110 in part.If the second penetrating fluid decline step 104 continues to carry out being drained until jar, then provide test to the integrality of all films 24 to the monitoring of air collecting amount in the air collector 70.

In another optional embodiment, the reversed order of penetrating fluid decline step 104 and backwash step 106.Therefore, after the impregnation step 102 of balance, water level raises along with backwash step 106.This needs jar 20 to have the freeboard of raising, but has also improved the available transmembrane pressure of penetrating fluid decline step 104 (TMP).Water 22 has also diluted solid by backwash step 106 in jar, can reduce the incrustation of film 24 between penetrating fluid step 104 decrement phase like this.Implement air douche step 108 in can also be during backwash step 106, wherein for whole backwash step 106, film 24 all is immersed in jar interior water fully.Very effective air douche step 108 can be provided like this.

In another optional embodiment, after penetrating fluid decline step 104, implement for a jar drain step 110.Backwash step 106 implements and becomes the part of the filling step 100 of next group after giving jar drain step 110.By this embodiment, the solid that is pushed away film 24 during backwash step 106 does not leave jar, until jar drain step 110 of giving of next circulation.But for the penetrating fluid decline step 104 of given length, the volume of the water that is discharged is very little.Air douche step 108 before the penetrating fluid decline step 104 or during, implementing during the backwash step 106 or before or after balance impregnation step 102.

Fig. 6 and 7 has shown second reactor 111.Second reactor 111 and the difference of reactor 10 are to have by each overflow area that is communicated with 112 in opening 114 and three jars 20 or such as the overflow area on weir, described opening 114 can be pipe, lock, and has the opening that operationally opens and closes between overflow area 112 and each jar 20 or the return valve 116 of pipe.It is above and make water flow to overflow area 112 from this jar 20 when water level is in the water level B of jars 20 rising that opening 114 is positioned at normal infiltration water level A.When opening, return valve 116 makes water be back to film jar 20 from overflow area 112.Although show three film jars 20, also other quantity can be arranged, for example 1 to 10 film jar links to each other with single overflow area 112.Each jar 20 has relative whole elements in the reactor shown in Figure 1 10, but in order to simplify view these elements is not shown.Each jars 20 can with the dilution discretely of other jar, perhaps when needs, if overflow area 112 than shown in bigger, then all jars 20 can be simultaneously diluted.

Each jar all lives through the filtering technology circulation.But can stagger between jar 20 opportunity of these circulations, and making once only has a jar 20 to need to use overflow area 112.Like this, the size of overflow area 112 can be become be used for surely a jar 20 rather than all jars 20 of second reactor 111.

For each jar 20, this technology is from aforesaid filling step 100.Afterwards immediately following the impregnation step 102 of balance is arranged, its middle water level is in case more than 28 but at overflow pipe below 114, for example shown in line A place.Return valve 116 cuts out.After the infiltration of balance, implement backwash step 106.Impel water from jar 20, to rise to for example water level B like this, and overflow in the overflow area 112.During this step, return valve 116 can open or cut out.If return valve 116 stays open during this step, then overflow pipe 114 can save or replace with the wall that extends beyond water level B.After backwash step 106, implement penetrating fluid decline step 104.Return valve 116 is opened during this step so that the water in the overflow area 112 can be back to jar 20.Penetrating fluid decline step 104 can be proceeded until reach required water level in jar 20, and for example however water level C or at water return valve another water level below 116 also can select the water level of return valve more than 116.Implement drain step 110 then, get back to the filling step 100 of next circulation afterwards, and utilize supply water or second to reflux and implement described filling.Return valve 116 cut out before filling step 100.Also can before the described technology or during, for example one or many provides air douche step 108 during the backwash step 106.The advantage of this technology is: the volume of the water of discharging is less than the volume of jar 20 during drain step 110; Can case 28 immerse fully and by the situation of back scrubbing under implement air douche step 108; And in most of process of implementing penetrating fluid decline step 104, all with the water in the penetrating fluid thinning tank 20 of back scrubbing.This dilution is with after backwash step 106 and exist the situation of implementing penetrating fluid decline step 104 under the situation of the solid that back scrubbing discharges different.

In having above-mentioned all technologies of penetrating fluid decline step 104, can carry out abundant draining to jar 20, be used for next circulation with abundant thinning tank 20.For example, last giving in jar drain step 110 before the filling step 100 of next circulation, the water of jar 20 can be discharged into full-water level or design fill water level less than 40% or less than 10% water level, perhaps emptying.Solid concentration can reduce make next in when beginning circulation solid concentration be the impregnation step 102 of the balance solid concentration when finishing 40% or still less.

Below with reference to Fig. 8 and Fig. 9 additional or improved technology are described.Although these technologies can be used for the film unit of any kind, they are for vertically being positioned at hollow-fibre membrane 24 between upper header and the lower collector pipe 26 or only particularly useful from the upwardly extending film of lower collector pipe 26 24.Immersion doughnut membrane filtration system also can run into sometimes owing to solid on film 24 and gather some technological problemses that produce on every side.Solid can accumulate to the degree that they begin to dewater and form the gunk that is called as mud.In some modules, solid or mud tend to mainly gather in some position, for example directly accumulate on the lower collector pipe 26 in the vertical fibers module of the loose upper end with upper header or fiber.In some embodiments of the invention, provide a kind of being used for to remove solid, be deposited on the fiber or to the fiber of the incrustation technology of cleaning because a large amount of mud are piled up with the mud that prevents from basically to gather from fiber.

Referring now to Fig. 8, a kind of technology is shown with flow chart.This technology provides carries out partial drainage and has the effect of part dilution thus jar, still effectively ventilates simultaneously, particularly ventilation is wherein ventilated the bottom of crucial film 24 very much, and ventilation and draining can partly be carried out simultaneously.Described technology comprises initialization step 1-1, impregnation step 1-2, stops impregnation step 1-3, draining and aeration step 1-4, stop the aeration step 1-6 of drain step 1-5, continuation and jar is recharged step 1-7.These steps can only be implemented in order to clean film, can combine further for another technology of jar draining with comprising, and perhaps can be used to form all or part of of concentrating of frequently repeating during the batch operation of filtration system and dilution circulation.Followingly in more detail each step is described with reference to Fig. 1-4,10 and 11.

In initialization step 1-1, feed pump 12 will be supplied with water 14 and 16 18 be pumped into jars 20 by entering the mouth from the water source, supply with water water 22 in jar 20 places become jar.Jars 20 are filled into jar water level of interior water 22 when covering interior one or more films of jar 20 24 fully.

During impregnation step 1-2, penetrating fluid 36 extracts from jar 20 by film 34.Draining valve 40 can cut out.Penetrating fluid valve 34 and outlet valve 39 are opened and are permeated liquid pump 32 and open.With respect to jar interior water 22, in the permeate side formation negative pressure of film 24 around film 24.By film 24 (then being called as penetrating fluid 36), film 24 filterings simultaneously are retained in the solid in jar interior water 22 to resulting transmembrane pressure with 22 suctions of water in the jar.Therefore, export 38 places at penetrating fluid and produce the operational penetrating fluid that has filtered 36.Storage pot valve 64 can periodically be opened and make penetrating fluid 36 enter storage tank 62.When the penetrating fluid 36 that has filtered was removed from jar, feed pump 12 operations were to remain on water in the jar 22 at the water level place of coverlay 24.

Each circulation, impregnation step 1-2 can continue 15 minutes to 3 hours or longer, 15 minutes to 40 or 45 minutes or 45 to 90 minutes.Especially, if impregnation step 1-2 is 45 minutes or longer, then in impregnation step 1-2, middle back scrubbing or aeration step can be arranged.During impregnation step 1-2, solid may be in jar the permeability of water 22 inner accumulated and film 24 reduce along with the incrustation of film 24.The end of impregnation step by film 24 reduce to the permeability of preliminary election, the duration of experience, the time that has reached or time and day, the amount or the decision of other means of the penetrating fluid that produced.At this moment, impregnation step 102 finishes.In stopping impregnation step 1-3, infiltration liquid pump 32 and feed pump 12 disconnects, and penetrating fluid valve 34 and outlet valve 39 are closed.

At step 1-4, process for purifying begins along with the initialization of giving 20 drainings of film jar, and begins ventilation simultaneously.Selectively, ventilation beginning can be before jar drains beginning, perhaps gives the beginning of jar draining can be before the ventilation beginning, although to begin when the liquid water level is near module 28 tops or its at least be preferred in ventilation.

In order to give 20 drainings of film jar, draining valve 40 open so that include the solid that concentration improves and in the jar that is called as stagnant liquid 46 water 22 flow to drainpipe 44 from jar 20 by stagnant liquid outlet 42.Be detained liquid pump 48 and can open giving a jar draining quickly, but in many equipment, only just can be enough apace with the jar emptying by gravity.In mostly industry or municipal equipment, to spend 2 to 10 minutes usually, and more frequent be to drain jars 20 in 2 to 5 minutes fully.Between drainage period, ventilation is proceeded.

With reference to Figure 10, before step 1-4, water 22 is illustrated and is in water level A place, film module 28 top in jar.Then, as shown in figure 11, when during step 1-4, carrying out draining, represent jar mid water levels of interior water 22 than low water level B.Along with the draining of jar 20, the solid-liquid interface that bubble bursts herein crosses the part of film 24 surface areas, this part can up to film 24 surface areas 50% or more, for example between 10% to 30%.During this period, still partly ventilate for the immersion of film.At step 1-5 place, draining suspends or stops at water level C place, and this water level can be known or suspection will form the suitable water level in the zone that mud gathers on the film 24 near.Make like this and preferably include known zone near the effective coverage of the energy burst bubble can flushing liquor-gas interface with mud problem.Alternatively, water level C can be in for example fill water level or design water level 70% to 90% between water level, this water level needs less draining just can reach and keep the major part of film module 28, comprises that the bottom of film module is dipped into.Selectively, can also be with known or suspect and to form regional corresponding one or more additional water levels place time-out that mud gathers or to stop draining.

In step 1-4 or 1-5, provide ventilation by aerating system 49 with air feed pump 50, described air feed pump is blown into the one or more breathers 56 that are usually located at film module 28 belows from air inlet 52 by air distribution 54 with air, nitrogen or other suitable gas, and described breather is dispersed in bubble 58 in jar interior water 22.Throughput can be that module 28 every square metre areas transmit 10 to 60 cubic feet of per minutes (cfm) in plane.The solution-air interface is washed and risen to the part that the bubble of 58 pairs of films 24 of bubble passes through, and they burst there, releases energy and form turbulent flow in the water 22 in jar.

Selectively, back scrubbing can also be during the arbitrary steps of step 1-2 in the 1-7 or between carry out or carry out at two or more places of these steps.For example, can in step 1-6 or between step 1-3 and 1-4, carry out about 30 seconds back scrubbing.Can use two types back scrubbing, promptly totally with reference to described penetrating fluid of Fig. 1-4 or chemical back scrubbing.

Shown in step 1-6, at water level C place, ventilation continues to carry out time period T ₁, this time period T ₁Can be in 30 seconds to 2 minutes scope.Then, film jar 20 is filled once more at step 1-7 place.Selectively, some or all in the remaining liq of jar 20 can be drained before step 1-7 to remove mud and further thinning tank 20.When giving jar 20 further drainings, can proceed ventilation.Alternatively, removed mud can be removed between the repetition of 1-7 or stagnant liquid draining period in subsequently dilution, step 1-3.Because this method can be used for providing certain at least ventilation to the whole surface area of film 24, so this method can be used for replacing other aeration step that adopts in addition in this technology.T ₁Can select according to the frequency that this method is implemented.For example, the enforcement frequency of this method can one day 2-100 time between weekly, T in this case ₁Chosen longer preventing that big mud from piling up rather than remove existing mud and pile up, and T ₁It can be 30 seconds to 5 minutes.If the frequency that this method is implemented is lower, for example arrive once a day biweekly and per two months once between, T then ₁Can be longer, for example between 2 minutes to 20 minutes.For example, if water level C full-water level or design water level 70% to 90% between, then can implement this method, and draining valve 40 cuts out during impregnation step 1-2 with 3 hours or shorter circulation.In this case, carrying out partial drainage to jar just dilutes similar with the discontinuous discharging or the part of each circulation.T ₁It can be 2 minutes or shorter, because step 1-6 frequently carries out.If water level C is lower, for example near lower collector pipe 26, then can be to implement this method long circulation timei, and draining valve 40 can be opened continuously or periodically during impregnation step 1-2, ventilation in the middle of perhaps step 1-2 can comprise, back scrubbing or dilution incident are with overall supply and discharging or the batch process that periodic interruptions is provided.In this case, T ₁Can be longer, for example up to 20 minutes or between 2 minutes to 20 minutes.When described technology provides periodic interruptions to another technology described here, for example once a day to one month once between, T ₁Also can be longer, for example between 2 minutes to 20 minutes.

When bubble rise by jar in during water 22, they form turbulent flow and shearing force on the surface of film 24, it can be controlled incrustation to a certain extent and amass silt.The inventor also has been found that when bubble arrives the liquid that is in usually during permeating above the membrane fiber-gas interface, and they are at the surprising energy of liquid-discharge when the gas interface bursts.In some embodiments of the invention, burst the membrane fiber that energy that bubble discharges is used to prevent the incrustation of membrane fiber and/or cleans incrustation at liquid-gas interface place.In these embodiments, the technology that is used to prevent and/or remove mud comprises water level is adjusted to can observe water level and ventilation a period of time that extensive film incrustation and/or mud are piled up in its vicinity, make the energy that discharges in liquid-gas interface place can refill the film jar and proceed infiltration or continue jar drained fully before act on the mud.Water level is adjusted to the specific region to be provided by bubble for these specific regions to burst the reinforcement flushing that is caused at liquid-gas interface.Usually, specific target areas is those zones that are easy to pile up mud, for example has or do not have the zone directly over the lower collector pipe of film unit of upper header, perhaps more among a small circle, is positioned at the zone under the upper header.This prevent and/or cleaning helps reducing otherwise can accumulate in the sludge quantity on the membrane fiber or remove the mud gathered.And, this prevent and/or cleaning can make membrane fiber be used in may to take place under the situation that serious and harmful mud gathers.

Referring now to Fig. 9, show second technology that is used to prevent film jar 20 inner membrance fiber incrustation or cleans membrane fiber.This technology comprises initialization step 2-1, impregnation step 2-2, stops impregnation step 2-3, liquid level regulating step 2-4, aeration step 2-5 and film jar recharge step 2-6.These steps can only be implemented in order to clean film, can with comprise another technology to the jar draining and combine and carry out or can be used to form all or part of of concentrating of during the batch operation of filtration system, frequently repeating to implement and dilution circulation.Following with reference to Figure 12 and continue in more detail each step to be described with reference to Fig. 1-4.

Step 2-1 is identical to 1-3 with the above step 1-1 that describes with reference to Fig. 8 respectively to 2-3.The others of method shown in Figure 9 are also same or similar with method shown in Figure 8, so no longer repeat.With reference to Figure 12,2-4 begins with step, and the liquid levels in the film jar 2 are reduced to the place, top or near the liquid level E in the zone that mud gathers.Liquid level E or the liquid level C in some embodiment shown in Figure 11 can be in 30 centimetres of film 24 bottoms, for example in 30 centimetres of lower collector pipe 26 tops of vertical fibers module 28 or in the lower collector pipe 26 of the module 28 of vertical fibers 24 or unique collector 26 20 centimetres or 15 centimetres.The module 28 of other structure may have other zone that mud gathers.

At step 2-5, can carry out a period of time T ₂Ventilation, T ₂Can be in 30 seconds-20 minutes scopes.The bubble that bursts provides enough turbulent flows, with the membrane fiber of the liquid-following depth D of gas interface of cleaning liquid level E place effectively.This degree of depth depends on ventilation intensity, and in the present embodiment, and it can reach following 30 centimetres and/or be enough to reach the bottom of film 24 or the lower collector pipe of the module of vertical fibers or the top of unique collector of liquid level E.If there are a plurality of zones that are easy to accumulated sludge or accumulated solids in module 28, then step 2-4 can repeat one or many at different liquid level places with 2-5.After last aeration step 2-5, the film jar further or is fully draining jar to fill once more after removing removed mud immediately alternatively at step 2-6.Because this method to the whole surf zone ventilation of film, therefore when for example influencing another aeration step of whole film surf zone during step 2-2 or between step 2-3 or the 2-4 during the another part in described technology, can not used this method.T ₂Accurately the duration can with T ₁Identical, and press T ₁Described mode is selected.In arbitrary method, T ₁Or T ₂Also can be variable, perhaps these methods can combine.For example, the method among Fig. 8 or Fig. 9 can be with short T ₁Or T ₂Frequent enforcement, but in same technology, the method for Fig. 8 or Fig. 9 also can be with lower frequency and long T ₁Or T ₂Implement.

Can also carry out other improvement to these technologies.For example, to regulate can be penetrating fluid decline step in the step 104 shown in Figure 5 for draining among the step 1-4 or the liquid level among the step 2-4.In addition, jar water 22 can be that waste water and filtering to provide is quoted, the water of municipal administration or industrial water.In addition, jar can step 1-6 or 2-6 after, fill a vacancy once more, and need not draining to suspending below the water level, and mud is then by the concentrate discharging or in next dilution, cleaning or give in the jar draining and remove.In addition, the present invention can be used for non-batch process, for example the water in the jar is discharged into other cistern by step 1-4 or 2-4, again jar is filled from this cistern then, perhaps according to giving the allowed frequent degree of jar draining or owing to the required frequent degree of other reason is implemented the present invention.

The technology that Figure 13-15 expression is other.Although be designed to the supply and the exhaust system that improve ventilation continuously, these technologies also can be applied to other or newly-built system.

Figure 13 represents and similar and another technology that can implement in the scope of technology shown in Figure 8 in some cases shown in Figure 8.Infiltration is at T ₀Beginning also lasts till T ₁T ₀And T ₁Between time for example can be 15 minutes to 40 or 45 minutes, it can be the dead end infiltration of not extracting stagnant liquid.At T ₁, infiltration stops and backward erosion and ventilation beginning.Backward erosion and ventilation continue 15 seconds to 5 minutes or 30 seconds by 90 seconds until T ₂At T ₂, back scrubbing stops and beginning the jar partial drainage or fills once more.During draining/is once more filled, the part of water 22 in jar, for example expire volume or conventional volume (for example average external volume or the design volume of the water that during permeating, exists) 5% or 10% to 25% between, from jar 20, drain and then with 14 replacements of new supply water.The amount of removing can be relevant with the required rate of recovery.Part film 24 exposes during these steps.These steps are flower for example 30 seconds to 5 minutes and at the T of next circulation beginning possibly ₀The place finishes.Ventilation can be proceeded the time T that occurs until during the filling step of draining/once more ₃Also can during the filling step once more of this technology or in the filling step of any other technology described herein, ventilate.Ventilation finishes in the time of can or beginning before filling jar 20 beginnings once more.The same with technology shown in Figure 8, can also be in draining and fill once more between ventilation time out section is arranged, perhaps fill and can after draining, begin immediately.Compare with discharge technology with the supply of continuous ventilation, technology shown in Figure 12 can make the amount of required ventilation reduce 90%-95%, still arrive the solid load of high concentration in handling simultaneously, for example the overall suspended solid (TSS) of 1000mg/L in jar interior water 22 or the stagnant liquid 46.Carry out partial drainage apace and fill once more although equipment must be modified or build to provide, compare the improvement that above-mentioned arts demand is less or the less draining and the capacity of water supply with having jar drained fully with the batch process of filling step once more.This technology provides part dilution, and after solid discharges from film 24 by backward erosion and ventilation or meanwhile carry out draining.

Figure 14 represents another technology.At T ₀The place, film by back scrubbing and the ventilation until T ₁T ₀And T ₁Between time can for example be about 10 seconds to 60 seconds or about 15 seconds.As shown in the figure identical time needn't take place or continue with ventilation in backward erosion exactly simultaneously.At T ₁The place, infiltration that is used for suspending again and ventilation beginning.As shown in the figure, ventilation can be intermittently, for example with aforesaid conventional ventilation amount every 1-4 minute or approximately carried out 5-20 second or about 10 seconds in per 2 minutes.Alternatively, the continuous ventilation that can provide throughput to reduce.Basically continuous discharging or filtering is provided in whole circulation usually.This circulation can continue for example 10 to 20 minutes or about 15 minutes.

Compare with discharge technology with the supply of continuous ventilation, ventilation can reduce about 80%-85%.Only need aerating system is made improvement.But this technology may cause the flux of the film in medium or the high solid concentration equipment to reduce or gather mud sometimes, but this technology is enough to be used in low equipment to medium solid concentration.

Figure 15 represents another technology.At T ₀Place beginning backward erosion, ventilation and filtering.For example after 10-30 second or about 15 seconds, promptly at T ₁Place's backward erosion stops and permeating beginning.Ventilation is proceeded until for example can being T ₀Approximately 60-120 second or about 90 seconds T afterwards ₂Waste material is removed and is proceeded until T ₃At T ₃Afterwards, waste material is removed and is stopped to permeate simultaneously the T that proceeds to next circulation ₀T ₃Be chosen to be at T ₂Comprise a period of time afterwards, the TSS concentration in the waste material is because backward erosion and ventilation still keep higher at this moment, and this section period for example can be T ₀About 5-10 minute or about 7.5 minutes afterwards.The amount of removing of selected waste material or prolongation T ₃Stagnant liquid with the volume that obtains to want to remove.Alternatively, if until T ₃Waste material is removed water in the jar of all not removing enough volumes, and then filtering can be at T ₀Begin once more before.Can be for example approximately 10-20 minute or about 15 minutes total circulation timei, and can for example circulating continuancing time about 2/3 1/2 or less time in extract waste material.The amount of the stagnant liquid 46 that each circulation is removed can be jar 20 volumes 5% to 25% between or between 5% to 10%.The amount of removing of waste material 46 can be the 10%-20% of the on average amount of removing of penetrating fluid 36.Average on whole circulation, the amount of walking of stagnant liquid 46 can be the amount that produces the yield between 80% or 90% to 95%.It is constant that the amount of removing of penetrating fluid 36 can keep, and wherein supplies with the variation of water 14 input quantities to keep jar water level of interior water 22 substantial constant or to keep the water level of water 22 in the jar to be in the acceptable scope.Alternatively or additionally, can have a mind to make jar water level of interior water 22 that to a certain degree fluctuation is arranged, for example during back scrubbing, rise, and when stagnant liquid 46 is extracted and may enters circulation once more, descend.

Compare with discharge technology with the supply of continuous ventilation, this method can make ventilation reduce by 80% or more.Must make equipment or design and revising so that the waste material flow that allows to improve, for example 150% of the design discharge of continuous blow-down equipment or twice or bigger, but those are revised than the correction that is used to have to the batch process of canful draining and lack.During can handling, this technology waits until high solid load.

In above paragraph, in whole infiltration, use ventilation with the cycle of opening 10 seconds passes in 10 seconds with the supply of continuous ventilation and the continuous supply of ventilating of relatively supposition and the discharge technology of discharge technology about Figure 13-15.Afterwards, low solid content has the supply TSS less than 5mg/L in flocculation (if existence).In flocculation (if existence) afterwards, the highly filled supply TSS that has above 50mg/L.Intermediate solid content between the two, for example 5mg/L between the 50mg/L or at 5mg/L between the 25mg/L.

Above stated specification only is an exemplary embodiment and not limiting the scope of the invention, and the present invention can implement with various flexible programs.

Claims (35)

1. membrane filtration process in batches comprises the following steps of implementing with repetitive cycling:

(a) jar is filled so that film is immersed in the jar;

(b) afterwards, penetrating fluid is extracted by the film water of increasing supply simultaneously and be dipped into to keep film in step (a);

(c) afterwards, extract penetrating fluid and reduce or stop to supply with current simultaneously to reduce a jar interior water level in step (b);

(d) back scrubbing film; And

(e), give a jar draining at step (a) and (b) and (c) afterwards.

2. technology as claimed in claim 1 is characterized in that, step (d) is carried out afterwards and in step (e) before in step (c).

3. technology as claimed in claim 1 or 2 is characterized in that, in step (c), jar part that interior water level is lowered to film is exposed to airborne degree.

4. technology as claimed in claim 3 is characterized in that, step (d) is carried out afterwards in step (c), and the volume of the water that is provided during step (d) is exposed to airborne described part with film and immerses once more.

5. technology as claimed in claim 4 is characterized in that, when the described part of film is immersed once more or utilize the air douche film afterwards.

6. technology as claimed in claim 2 is characterized in that, step (c) repeats to implement in step (d) afterwards and in step (e) before.

7. technology as claimed in claim 1 is characterized in that, step (d) is carried out afterwards in step (e).

8. technology as claimed in claim 7 is characterized in that, in step (d) afterwards, step (e) repeats to implement getting back to the step of next circulation (a) before.

9. technology as claimed in claim 8 is characterized in that, step (c) repeats to implement in step (d) afterwards and in repetition implementation step (e) before.

10. technology as claimed in claim 1 is characterized in that, in step (c), (d) or (e) before the arbitrary steps, during or between utilize the air douche film.

11. technology as claimed in claim 1 is characterized in that, step (d) is implemented before in step (c).

12. technology as claimed in claim 1 is characterized in that, is exposed in a part that water level is reduced make film to begin perhaps back scrubbing draining then to the jar draining airborne the time.

13. technology as claimed in claim 1 is characterized in that, described technology also comprises the technology that is used for removing solid from the membrane fiber module that is immersed in liquid, and the described technology that is used for removal solid from the membrane fiber module that is immersed in liquid comprises:

(f) the liquid water position is reduced to regional corresponding water level with membrane fiber with buildup of solids; And

(g) liquid be in membrane fiber have the described zone corresponding water level of buildup of solids the time, the ventilation of a period of time is provided.

14. technology as claimed in claim 13 is characterized in that, the described technology that is used for removal solid from the membrane fiber module that is immersed in liquid also comprises afterwards in step (g):

(h) the liquid water position is reduced to membrane fiber have buildup of solids another the zone corresponding second water level; And

(i) when being in second water level, liquid provides the ventilation of a period of time.

15. technology as claimed in claim 1 is characterized in that, ventilates off and on when described technology also is included in infiltration.

16. technology as claimed in claim 15 is characterized in that, carries out 5 seconds to 30 seconds ventilation in infiltration in per 1 minute to 5 minutes.

17. technology as claimed in claim 15 is characterized in that, ventilates when described technology also is included in back scrubbing.

18. technology as claimed in claim 1 is characterized in that, described technology is non-recirculating process.

19. technology as claimed in claim 1 is characterized in that, circulation timei is between 15 minutes to 40 or 45 minutes.

20 technologies as claimed in claim 19 is characterized in that, be 30 minutes or still less circulation timei.

21. technology as claimed in claim 1 is characterized in that, described supply glassware for drinking water has 0.05g/L or littler overall suspended solid.

22. technology as claimed in claim 1 is characterized in that, the rate of recovery is 80% or 90% at least.

23. technology as claimed in claim 1 is characterized in that, membrane flux is 40L/m ²/ h or bigger.

24. technology as claimed in claim 1 is characterized in that, membrane flux is 50L/m ²/ h or bigger.

25. technology as claimed in claim 1 is characterized in that, membrane flux is 60L/m ²/ h or bigger.

26. technology as claimed in claim 1 is characterized in that, for every cubic metre tank volume, the film surface area is 250m ²Or it is bigger.

27. technology as claimed in claim 1 is characterized in that, for every cubic metre tank volume, the film surface area is 350m ²Or it is bigger.

28. technology as claimed in claim 1 is characterized in that, during permeating, per hour extracts at least 6 times to the penetrating fluid of tank volume.

29. technology as claimed in claim 1 is characterized in that, during permeating per hour 6 of the extractor volume to 70 times.

30. technology as claimed in claim 1 is characterized in that, in back scrubbing, the penetrating fluid volume that enters once more jar be tank volume 10% to 50% between.

31. technology as claimed in claim 1 is characterized in that, in back scrubbing, the penetrating fluid volume that enters once more jar be tank volume 10% to 40% between.

32. technology as claimed in claim 1 is characterized in that, the element of hollow-fibre membrane with the film that extends downwards from collector is ventilated, and water level remains between following 1 to 10 centimetre of the bottom surface of described collector.

33. technology as claimed in claim 1 is characterized in that, ventilates when jar is filled wholly or in part.

34. technology as claimed in claim 1 is characterized in that, supplying with glassware for drinking water has 0.2g/L or littler overall suspended solid.

35. technology as claimed in claim 1 is characterized in that, stagnant liquid has 1g/L or littler overall suspended solid.

Images