Summary of the invention
An object of the present invention is to overcome or improve at least one shortcoming of prior art, perhaps provide the alternative of usefulness.
According to an aspect, membrane filtration system provided by the invention comprises: the charging container; Be arranged in the membrane module of described charging container, this membrane module comprises one or more hollow permeable membranes that are used for filtration feed liquid; Be used to apply the device of the pressure reduction of the wall that passes described film, apply this pressure reduction and cause the filtration of passing described film; The feed liquid holder, it becomes fluid to be communicated with to supply feed liquid to this membrane module with described membrane module; The feeding liquid body source; Gas source; Be used for optionally producing gas stream and producing the device that feed liquid flows from described input fluid supply from described gas source, this gas stream and liquid stream enter described feed liquid holder through described membrane module, and described gas stream produces bubble to clean described film in described feed liquid.
Preferably, be used to produce the device that gas flows and feed liquid flows and comprise pump.As preferably, gas source comprises that gas holds holder.Preferably, pump is arranged on the gentle body of feeding liquid body source and holds between the holder, and is communicated with their fluids.As preferred, gas holds the holder fluid and is connected to described charging-container.Preferably, check valve is arranged on gas and holds between holder and the charging container, flows to the charging container to allow fluid to hold holder from gas.As preferably, pump can optionally move according to the liquid level of feed liquid in the feeding liquid body source.Preferably, described feeding liquid body source comprises the feed liquid supply tank, and in described groove, be provided with first and second liquid level detection devices, described second liquid level detection device detects second liquid level of the feed liquid in the described groove, and this second liquid level is higher than first liquid level that is detected by described first liquid level detection device.Selectively, liquid level detection device can be incorporated into (certain has the immersible pump of built-in liquid-level switch) in the pump.The detection of described second liquid level of pump response feed liquid and moving, and the detection of described first liquid level of response feed liquid and out of service.
The alternative of liquid level control is timer control, wherein, timer is started by liquid-level switch, regulate this timer control more accurately can be provided the oxidation of feed liquid/membrane interface, this timer especially can be used to circulate between the biomembrane state of oxygen containing and anoxic, thereby at high BOD
5Film in produce in check denitrification, or under the aerobic bioreactor reactor condition, strengthen decolouring or remove flavor.In this arrangement, timer arrangement can start described pump and continue predetermined periods, described feeding liquid body source comprises the feed liquid supply tank, and in described groove, liquid level detection device is set, described liquid level detection device detects the predetermined fluid level of the feed liquid in the described groove, and the detection of the described predetermined fluid level of described timer arrangement response feed liquid continues described predetermined periods thereby start described pump.
Preferably, be used to provide the device of the pressure reduction that passes membranous wall to comprise the feed liquid holder is positioned on the liquid level of described membrane module, thereby hydrostatic head is applied in to described film, it causes the filtration by this film.Yet in another kind of embodiment, the pressure reduction that passes membranous wall can be by pump manufacturing or enhancing, and this pump is exerted pressure or in the suction of the filtration side of film at the feed side of film.Preferably, pump is identical with the pump that produces gas stream and feed liquid stream.In yet another embodiment, have the pressure vessel that is positioned at the air holder on the liquid and be used to the drive ram that provides higher.
According on the other hand, the invention provides a kind of method from many-composition feed liquid filtration filtrate, comprise the steps: to provide the source of described feed liquid; Gas source is provided; Gas is flowed through from described gas source comprise the membrane filtration module of one or more hollow permeable membranes, enter the feed liquid holder that is arranged on the described membrane filtration module then, with in film and/or produce bubble on every side so that remove the solid that gathers on the film; Make feed liquid cross film the described assembly, to sweep away the described solid of removing from described membrane filtration module from the feed liquid source and course; And, produce filtration through the feed liquid of described membranous wall by the hydrostatic head drive ram that the feed liquid that remains in the described feed liquid holder applies.
As preferably, respond the liquid level of the feed liquid at feeding liquid body source place, optionally control feed liquid stream and gas stream.
The specific embodiment
With reference to the accompanying drawings, the basic structure of preferred embodiment comprises three parts:
1. film unit 5, and it comprises the one or more filtering film components 6 that are positioned at feed containers 7.Assembly 6 generally includes one or more hollow permeable membranes 8.Film can be a fiber, pipe, thin slice or analog;
2. catch box 9, and it stores feed liquid so that be supplied to film to be used for filtration under gravity;
3. gas reservoir or chamber 10, its preservation is used for the necessary a large amount of gases of cleaning film, normally air.
Fig. 1 represents one embodiment of the present of invention.This embodiment comprises above-mentioned three parts.Pump 11 is attached to gas compartment 10 and is used to transport feed liquid (normally water) to film unit 5 and filters being used for.The operation of pump is determined that by two liquid-level switches (not shown) these two liquid level beginnings are operable in feed liquid liquid level H and the L part in the feed storage device 12.It should be understood that pump also can be to be attached to catch box 9 so that draw the vavuum pump of feed liquid through this system.
Feed entrance pipeline 13 by check valve NV1 control is connected between gas compartment 10 and the film unit 5.Unidirectional or gas inlet valve NV2 in addition is operatively connected to the gas access pipeline 14 of gas compartment 10.
In this embodiment and other embodiment described later, film 8 is arranged as vertical structure and is inserted in the upper header 15, their 17 one-tenth open fluid communication of upper end 16 and filtrate collection chamber, and their following free end 18 sealings, yet, will be appreciated that and to adopt any known suitable membrane module structure, comprise that film extends and the membrane module structure of the non-vertical installation of film between upper and lower collector.
Filtrate collection chamber 17 arrives filtrate storage box 20 via 19 windings of filtrate pipeline.Catch box 9 also preferably has overflow passage 21, and this overflow passage is positioned at the height place that can apply the feed liquid pressure head to film unit 5.Assembly outlet 22 be arranged on the following of upper header 15 or near, flow to into catch box 9 from the liquids and gases of assembly 6 allowing.
The operation of this embodiment will be described now.When in case the liquid level of feed water reaches predetermined startup liquid level H in the holder 12 in input, pump 11 beginning pumping feed water.When the feed liquid liquid level drops to by the indicated predetermined low liquid level of liquid level L in feed storage device 12, low liquid-level switch operation, pump stops.
When the feed water of pumping enters gas compartment 10, its Compressed Gas and promote gas and enter film unit 5 through check valve NV1 washes away film 8 and is released by catch box 9 via assembly outlet 22 subsequently.Compressed gas 10 is closed check valve NV2 in the gas compartment, so the gas in the chamber 10 can not be discharged in the atmosphere.
Along with the continuation of pump 11 operation, it transports feed water and comes to remove solid down by what air scour was swept away membrane module 6 from film, makes feed water through module vent port 22 inflow catch boxs 9 at last.Start cycle period at pump, feed liquid is filtered through membranous wall, and this depends on dynamic head and hydrostatic head in putamina body and the catch box 9.
When the charging in the reservoir (not shown) was reduced to liquid level L, the operation of pump 11 stopped.After feed pump 11 stopped, because the operation of check valve NV1, the feed water in catch box 9 and the film unit 7 can't reflux.Hydrostatic head between the charging liquid level in catch box 9 and the filtrate pipeline 19 is poor, has produced to pass the pressure reduction of membranous wall with the drive membrane filter process, arrives zero up to this difference.Simultaneously, after pump 11 stopped, the input water in the gas compartment 10 was back to the feed storage groove, and gas (being generally air) gas coming through entrance pipe 14 enters gas compartment 10 through NV2.This is used for loading again gas compartment, thereby prepares for the next one washes away circulation.
Gather in catch box 9 for fear of suspended solid, the fraction of inclusion can overflow catch box 9 with the discharging solid.Waste solid also can be by removing from catch box 9 manual drain or by high ability solids valve.
Gas and employing that embodiment shown in Figure 1 adopts gas compartment 10 to store and is used for cleaning film 8 store feed water to allow the catch box 9 of gravity filtration.Can understand the variation of this layout based on the present invention.For example, thus gas compartment 10 can be designed to reduce around the ring of film assembly 6 vertical height of system.
Fig. 2 represents another preferred embodiment of the present invention.In this embodiment, gas compartment 10 among Fig. 1 embodiment and check valve NV2 are replaced by Venturi tube 23 or analog.Venturi tube 23 can be any suitable device that is used to provide gas/liquid mixture.As shown in the figure, Venturi tube 23 is positioned in feeding pipe between pump 11 and the check valve NV1.
When pump operation,, feed water forms the two-phase gas/liquid flow of washing away film thereby sucking gas by Venturi tube 23.Feed water in the mixture is transferred through module vent port 22 and arrives catch box 9, and gas is discharged after washing away film 8.
The remainder and first embodiment of this embodiment operation are similar.
Fig. 3 represents the third embodiment of the present invention.Similarly, the whole operating process and first and second embodiment's is similar.In order to improve the cleaning efficacy of air scour film, Venturi tube 23 can be connected to gas compartment 10.This structure has overcome the necessary gas flow deficiency of fully washing away (infeasible at this big gas reservoir) that is used for film in first embodiment, allow simultaneously to be carried to the bubble part combination in the feed water and to form best bubble size, the most effective film 8 that washes away of this bubble size through Venturi tube 23.
Fig. 4 represents the fourth embodiment of the present invention.The whole operating process of this embodiment and aforesaid previous embodiment are similar, and the principle that is adopted may be used among these embodiment any one.
In this embodiment, catch box 9 seals substantially, and it is provided with the pressure-control valve 25 that is connected to catch box 9 by gas piping 26.Under the control of system controller, the liquid height in the catch box 9 can control to predetermined altitude by ball-cock assembly.
In use, by the operation of pump 11, gas and air are pumped by module vent port 22 in succession and enter catch box 9.Because catch box 9 sealings, the gas pressure in the catch box 9 is elevated to the predeterminated level that is determined by pressure-control valve 25.In case reach predetermined gas pressure, any extra gas is captured and returns to system as process gas supply gas pipeline 26.The auxiliary generation of gas pressure in the catch box 9 filtered necessary transmembrane pressure.
System described above can be used for guiding the filtration of water and waste water, perhaps can be integrated in the hybrid system that for example has biological treatment or condensed system.When this system integrated mutually with biological treatment process, during the air scour and when the nothing-air scour period promotes denitrification, film was also worked as fixing biomembrane and is reached the certain level of biologically active-oxidation of organic compounds.
Shown film is arranged the outer-inner filtration pattern that adopts among the embodiment, yet, will be appreciated that the present invention is equally applicable to interior-outer filtered model, wherein feed liquid and gas bubbles are washed away through the film inner chamber.Plate film assembly and analog also can be used in the system as membrane filter unit.
Will be appreciated that other embodiments of the present invention and example are possible, and can not break away from the spirit or scope of the invention of describing.