Patent Application
20090032448
The invention relates to an apparatus, a device, a compact unit and a separation assembly, respectively, as well as a method for separating solids from a liquid, in particular in the field of drinking or wastewater treatment.
The separation of coarse and suspended substances is an essential object in the field of environmental protection techniques, in particular in the drinking water treatment, in the process water or rain water treatment as well as in the wastewater discharge and wastewater treatment. The separation degree and the selectivity are substantially influenced by the specific surface feeding, wherein this is proportional to the separation grain size, e.g. of mineral, metallic or organic particles. For the separation of small separation grain sizes, reservoirs having very large surfaces have to be implemented without additional installed equipment. From the field of mining technical methods emerged which enabled an increase of the effective separation surface with small reservoir surfaces. The effective separation surface has been mainly enlarged by installing surfaces arranged parallel to each other, so-called lamellae comprising an inclined position (blade angle) in respect of the perpendicular. The liquid loaded with particulate pollutants circulates within the reservoir or basin over the lamella surface, where the particles are separated.
Due to the inclined position of the lamellae and the different physical-chemical characteristics (density, structure, surface load etc.) of the particles, in particular their lipophilic or hydrophilic characteristics, sedimentations on the lamellae are possible. The removal is carried out by relocating the lamellae between the separation position and a cleaning position. The angle in respect of the perpendicular is dependent on the desired separation grain size in the separation position. In the cleaning position the lamellae are approximately perpendicular so that due to gravity the sedimentations can slip off and thus the lamella surface is cleaned off.
The cleaning of the lamellae is, however, not only determined by their orientation, but also by the time period during which the cleaning off is carried out, i.e. the cleaning cycle. The switching between separation and cleaning positions is enabled in U.S. Pat. No. 4,514,303 by means of a motor-operated winch, wherein the cleaning cycle itself is manually controlled. This control has the essential disadvantage that always a visual control of the lamellae is necessary. In particular in covered basins this control results in with an increased effort in costs, personnel and accident prevention.
In document DE 697 01 121 T2 the change between separation position and cleaning position is carried out float-controlled (either by additional floats or by lamella material having a lower density than water), wherein the lamellae take the separation position during the filling procedure of the basin. The cleaning cycle is determined by the filling and emptying cycles of the basin. A change between the fill levels in the basins is a required precondition for a correct operation in this alternative. By means of this coupling between the fill level in the basin and the position of the lamellae this control alternative has two significant disadvantages, which are conditional on the normal emptying times in particular in the field of the wastewater discharge on the one hand and on continuously dammed-up basins on the other hand.
In the field of process and rain water treatment as well as in the field of wastewater discharge, the change between the filling phase and the start of the emptying of the reservoirs lasts in a lot of cases more than six hours. This damming-up time results in most cases from the size of the reservoir volume, the production processes, the size of the dewatering area and the load of the wastewater treatment plant. What has not been considered in the known devices is that the solid load, however, is fed to the basins and reservoirs, respectively, within the first 30 to 60 minutes, so that the lamellae should take the cleaning position during this time.
In the float-controlled alternative the sedimentations, here in particular the lipophilic substances, have enough time to accumulate at the surface of the lamellae and to form gel-like agglomerates. Also in the cleaning position these agglomerates can not be removed only by gravity and form, with increasing dam-up events, thicker and thicker films. In continuously dammed up basins, such as in the drinking water treatment, rain clarifiers, sand traps, primary and final sedimentation basins of wastewater treatment plants as well as activated sludge reservoirs, this control alternative can not be used at all, as the lamellae never take up their cleaning position with the basin completely filled up.
It is an object of the invention to provide an apparatus, a device, an arrangement and a method for separating solids from a liquid, in which a cleaning of a separation device is carried out in a cost-saving and cost-efficient manner. Further, it is an object to expand the cleaning and treatment effect of a separation device.
This object is achieved by the features of claims 1, 11, 20 and 23, respectively.
Advantageous embodiments are subject matter of the dependent claims.
To achieve this object a control value has been found, which enables a statement of the flow and solid conditions in the cleaning basin, and which is independent of the fill level. Within the environmental protection technique, in particular the rain water treatment and/or the wastewater discharge and/or the wastewater treatment, the use of flow and flow velocity, respectively, results in a cost-saving and efficient control of a separation device (e.g. separation lamellae) between its separation position and its cleaning position under all operation conditions in a basin.
For this a method, a device and a separation arrangement are proposed, in which the flow of the inflowing or outflowing liquid or the flow velocity are detected for example in the inflow or outflow region of the basin or reservoir or within the basin or reservoir. Generally the solid load of the liquid is directly proportional to the flow velocity, as both, load and velocity, are coupled to each other by the friction force. If the flow velocity is detected and transformed into a pressure and/or a force, the separation device or parts of the separation device can be positioned by this force so that its projected surface is adapted for the respective liquid supply or solid supply for the solid separating.
According to claim 1 the position of the separation device is advantageously influenced by means of a control unit so that the surface that is crossed by the flow is enlarged with starting or increasing flow, so that in the solid separation the effective surface and the surface effect, respectively, is increased.
If for the separation of solids the separation device comprises adjustably arranged separation areas, so-called lamellae, its adjustment is sufficient for the adjusted solid separation.
In an embodiment the flow velocity is detected by a control device comprising, for example, a housing and a flow body (referred to as ‘body’ in the following). In the control device the flow velocity is transformed into a dynamic pressure exerting a force to the surface of the body. This force results in a movement of the moveably arranged body in the control device, which in turn can be used for a position change or a change of the orientation of the separation surfaces. The movement can be transferred to the separation surfaces (lamellae) for example via a mechanic connection and thus change their position or blade angle.
The retraction force for the flow body can be generated, for example, by the weight of the lamellae or separation surfaces. Advantageously the lamellae or the lamella package comprise a higher medium density than the ambient liquid (e.g. water in the rain water treatment, wastewater drain or wastewater treatment), so that the downward impetus results in the retraction of the flow body. Alternatively or additionally a retraction force results from the buoyancy of the flow body itself if the medium density of the flow body is lower than the ambient liquid. Supportingly or alternatively the retraction is effected via a spring-operated retraction device (e.g. via a spring tension) or via a gravity-operated retraction device (e.g. weight of a weight element acts on the flow body or the lamellae opposite to the flow force).
As the movement change of the flow body is also proportional to the flow velocity, the blade angle becomes greater with a higher flow velocity and a solid load, so that the horizontally projected surface enlarges and more solids can be separated.
In the rain water treatment and the wastewater discharge the flow velocity decreases after the damming-up of the basin or the reservoir, and the flow body returns to its starting position, so that the lamellae resume their cleaning position. Independent of the damming length and the fill level, in this method the cleaning position is resumed again and again, so that the time periods are far too short to enable a non-removable sedimentation on the lamellae.
In the wastewater treatment the flow velocity follows the daily hydrograph of the wastewater, so that in these basins or reservoirs the cleaning position is resumed also at low inflow volumes and a cleaning off of the lamellae results.
Another embodiment comprises a control device having a perforated flow body. Thereby solids from the liquid can deposit during the flow-through process at the through holes and above and/or within the through holes, respectively, and thus increase the pressure drop by the body during the flow-through in dependency of the solid load. The increase of the flow pressure drop of the body results, in turn, in a movement of the same, which is used to change the position for the lamellae.
In a further embodiment the solid-loaded liquid flows within a channel along a connection element, for example along a tube. This element is connected to one side of a pressure unit comprising at least two pressure chambers separated by a membrane. The second pressure chamber is for example exposed to the ambient pressure. The two pressure chambers act as a differential pressure manometer, in which the membrane is flatly aligned in the zero position. Compared to the ambient pressure a lower pressure is generated by the flowing liquid, so that the biased membrane deflects from its central position. The change of the central position of the membrane can be used for controlling the lamellae.
The control devices mentioned above can only enable an indirect non-quantitative detection of the solids, whereas in an embodiment of the method, sensors are used, which allows indirect quantitative information in respect of the present solids in the liquid. With corresponding characteristics of the solids the mechanical sensor can determine in the control device, for example, the accumulated mass of the solids (sedimentation balance), the electrical sensor can determine the conductivity, the optical sensor can determine the opacity, and the hydraulic sensor can determine the viscosity. The measured values are transformed e.g. in a proportional signal. This signal can be transferred by the control device to an actuator and can carry out the activation of the corresponding lamella position in a mechanical, electrical, pneumatic or hydraulic way. If the solids content in the reservoir liquid or the position of the lamellae is detected by an additional sensor, the control circuit can be expanded to a feedback-loop circuit.
A cost-saving embodiment of the control device is the position change of the lamellae in time-discrete steps. A time switch can for example be used as a control device, which activates an actuator, diverting the lamellae for example in a half-hourly rhythm from their separation position into their cleaning position and which switches back into the separation position after, for example, five minutes of cleaning.
To enable a preferably easy and cost-saving construction of the entire separation device, the connection element between control device and deflection device or diverting device is formed in an embodiment, for example, as a rope, a chain or a rod-like bar. These connection elements can only transfer traction forces but no pressure forces. For this reason the connection elements have to be dimensioned to only one force direction and can therefore be provided with low weight. This kind of connection elements advantageously result in little mass moments of inertia so that the control device has to bring up only minimal additional actuating forces to change the lamella position.
In the liquids to be treated, for example rain water, there are not only particulate substances but also solutes, such as heavy metals, nitrate, nitrite, chlorides, sulfates or organometallic compounds which can be adsorptively bonded via active media, such as charcoal, active coke, clinoptiolith or hydroxyl apatite. Therefore, a composite arrangement of the lamellae is proposed in an embodiment of the method. The composite arrangement of the lamellae can be formed so that the material, including the active layers for removing the solutes, is detachably or irremovably connected to the actual separation surfaces. The detachable connection has the advantage that the adsorbents can also be subsequently adapted to special contaminants in the liquid.
In an embodiment of the separation surface the same comprises a composite assembly. In an irremovable connection the composite assembly has the advantage that the lamellae have lower weight and can thus be mounted with less effort. This is particularly advantageous, if the separation device is installed in covered buildings, such as ducts or rain basins.
With an automatic cleaning of the lamellae by their position change the force disequilibrium between the adhesive force of the separated solids on the separation surfaces and the gravity effect on the separated solids is utilized as cleaning mechanism. For this reason the cleaning effect of gravity can be improved by minimizing the adhesive forces, depending on the solids and the characteristics of the lamella surface. In an embodiment the lamellae are coated with nanoparticles (lotus effect), effecting a change of the surface potentials. Thereby, for example lipophilic solutes can be transferred into particulate substances and separated at the lamella surfaces. For the lamellae synthetic materials can also be used, which have a special scale-like surface structure (shark effect). By means of this surface the boundary layer characteristics are particularly positively influenced so that the adhesive forces in aqueous ambient media are minimized and the solid sedimentations advantageously slip off more easily in the cleaning position.
In order for the separated solids not to be re-suspended, they have to be collected in the separation device and have to be discharged as promptly as possible. In rain basins in bypass and for reservoirs an additional discharge element has to be provided for the solids. In an embodiment of the method, robust conveying elements, such as a pump having a Hardex conveying wheel or a conveying screw, are employed for the solid input. Particularly advantageous is a conveying element that does not require moved parts for conveying, such as an airlift.
In basins or reservoirs in the discharge system in which a work-off is carried out, i.e. a change between filling and emptying, the separation device can be provided with a hydraulic device to remove the solids. The removal of the separated solids is carried out after emptying the basin or reservoir. To clean these basins, hydraulic devices, such as rinsing dumps, flap-provided or flap-free rinsing chambers as well as spray nozzle rails, which generate a cleaning flush, are particularly appropriate. In these methods the solid transport is advantageously carried out by the friction force of supplied hydro power so that no wear can be caused by mineral particles.
Advantageously the separated particles are collected below the separation surfaces and discharged out of the reservoir or basin by a conveying element (for example a pump), a conveying screw or an airlift. In another embodiment or additionally the separated particles are collected below the separation surfaces and are discharged out of the basin or reservoir after the work-off of the basin or reservoir by a cleaning device, such as a rinsing dump, a flapless flush cleaning or a spray nozzle rail.
The simplest and thus most cost-saving device for controlling the position of the separation surface or surfaces is that the control device is integrated into the separation surfaces. To achieve this, the separation surfaces are for example rotatably supported, and a partial flow or the entire supplied liquid and thus the supplied solids are flown against a portion of the surface. Due to this hitting flow, a force is exerted on this portion of the control device/separation surface combination, which results in a position change around the rotation axis. To intensify the effect of the hitting flow, a portion of the surface or the entire surface acting as control device can advantageously be bent up to an angle of 90° relative to the separation surface.
In an embodiment of the device it is advantageous to effect a movement or lifting of a flow body by the inflowing liquid, wherein the flow velocity is transformed into a force. In the field of fluid techniques the flow velocity can be transformed with little effort into a flow pressure by a flow body, which can be transformed into a movement when the body is movably arranged. In this transformation by the flow body it is advantageous that the body is formed so that preferably no or only little separation turbulences are generated, which would cause additional force loss. The pressure force of the flowing liquid can be increased by a housing in which the body is guided. In respect of the design of the housing attention has to be paid in that the dynamic pressure acts as even as possible on the body so that it is not exposed to additional moments (for example moments of torque or tilt).
A cost-saving embodiment of the control device is for example to use a tube as a housing for the body, which, when a flow is passing, has at the same time the essential advantage of a radial-symmetrical distribution of the pressure forces and the pressure losses, respectively. In this assembly the pressure forces do not result in a rotation of the body receiving the pressure forces. The body for receiving the pressure forces should as well be rotational-symmetrically designed so that there is also an even force distribution on it. In flow-technical view the body for receiving the pressure forces could have a drop-like or simplified a tapered form and be arranged in the flow so that the turbulence losses are minimized. For guiding the body the housing can have at least one guiding element, for example a groove or a U profile. The body for receiving the flow pressure also contains a guiding element, wherein it should advantageously be a corresponding counterpart to the guiding element of the housing, for example a pin or a rail which are fixedly connected to the body.
The combination of the two guiding elements represents a linear guiding for the body which can dodge the pressure forces acting on it in the direction of the linear guiding and can thus change its position.
In an embodiment the flow body comprises e.g. a horizontally supported surface having at least one gap relative to the housing, so that the solid-loaded liquid flows through the gap and the pressure difference emerging thereby results in a deflection of the surface.
To transfer the position change of the flow body to the at least one separation surface (lamellae) either its guiding elements or the body are connected to the lamellae directly or via a connection element (for example via a synthetic rope which in turn can be guided via a diverting device). Or, if a transformation (gear transmission ratio/gear reduction ratio) of the body's movement is necessary, the body and the at least one separation surface are coupled or connected via a deflection device which in turn is mounted at its other end to the lamellae by a further connection element.
For the detection of the solid load of the liquid by a mechanically acting body, through holes provided in it are appropriate, which can clog dependent on the solid load in order to thereby increase the pressure drop proportional to the load and thereby deflect. In an embodiment of the device the body is for example formed as a flat plate comprising for example slit-like or circle-like through holes having different diameters from 0.5 to 5 mm. During the flow-through the body by the liquid to be cleaned the free cross-sectional area more and more decreases so that the flow pressure becomes higher and higher and more and more displaces the body in its guiding. The body is also provided with a connection element for controlling the lamella position.
In an embodiment of the control device deposited solids are removed from the flow body by e.g. activating a cleaning device, for example by an actuating mechanism, which is provided for example on the upper and/or lower travel position of the body including for example opposite through holes or raised parts, by means of which the surface of the body is cleaned. As the solids clog the through holes of the body, they have to be removed again from the through holes at the end of the control cycle. For this purpose at least one cleaning device is provided which for example is arranged at the upper or lower end of the travel path or advantageously at both ends of the travel path. In case of the above described exemplary body the cleaning device can consist of a plate having rips on which studs are arranged which fit into the respective through holes of the body. If the body reaches the upper and/or lower end position of its travel path, the studs break through the through holes and thereby remove the solid deposits from the body.
In an embodiment the deflection device or diverting device transforms a decrease or an increase of the actual signals or values (flow velocity, liquid level, solid load, opacity—see above) of the control device in a mechanical, electrical, pneumatic or hydraulic way. For example, the mechanic deflection device or diverting device comprise an asymmetrically acting lever in which the control device is connected for an up-transformation to the smaller lever part and for a down-transformation to the greater lever part; Or it includes a cam disk having an alterable diameter; Or an electrical deflection device or diverting device include for example an actuator. A pneumatic as well as hydraulic deflection device or diverting device include for example a travel piston.
Advantageously the control element is arranged in such a way that at hydraulic dwell times of about 5 mins the control characteristic of the lamellae is advancing and in a hydraulic dwell time of far more than 5 mins the control characteristic of the lamellae is lagging.
Another cost-saving embodiment of the body for receiving the flow pressure forces consists of at least one unilaterally supported plate moveably supported in the housing of the control device. At least at one lateral surface of the plate, advantageously opposite to the support, there is at least one latch mounted to the lamellae via connection elements. Between plate and housing there is at least one gap through which the solid-loaded liquid can flow. Dependent on the inflowing volume flow the pressure force and thus the adjusting force for the plate varies. The deflection of the plate is carried out around the pivotal point of the support and the retraction is carried out via the weight of the lamellae.
Advantageously the control device, through which at least one partial flow of the solid-loaded liquid flows, comprises an advantageously cylindrical housing, for example a tube section, and at least one guiding element, such as a groove or a U-shaped channel, in which a moveable body having at least one guiding element is arranged and connected at least at one end of the body or of the guiding element of the body to at least one deflection device or diverting device and/or to the separation surfaces via a connection element.
To position the separation surfaces or lamellae within the separation device a force has to be exerted which is generated by the dynamic pressure acting on the body in the control device. This force can act, as described above, either directly or indirectly on the separation surfaces. In respect of the indirect effect, constructive components such as connection elements or diverting and/or deflection devices or a combination of diverting and deflection device is required for the transmission of the force from the control device to the lamellae.
To minimize the inertia of the movement transmission between control device and lamellae, the connection elements should have a weight as low as possible. To enable this, as described in an embodiment, the force distribution between control device and lamellae should be selected so that in the connection elements mainly traction forces occur only, as almost all materials can transfer high traction forces in small workpiece dimensions, so that for example a rope can be used as connection element.
The essential function of the diverting device is that the force flow in the connection elements has to be guided so that in those mainly traction forces occur only. The diverting device or diverting devices can for example be composed of rolls in which the connection element is guided and the force always acts in axial direction of the connection element only.
The deflection device comprises in addition to the diverting device the function to change the movement between the control device and the lamellae. Thereby, with low liquid supply at high solid load, the movement is advantageously enlarged by the deflection device to thereby adapt the horizontally projected separation surface to the high solid ratios, and, with high liquid supply at low solid load, the movement is diminished to minimize the turbulences by the lamella positioning. A cost-saving solution for a deflection element is an asymmetrically acting lever, wherein the asymmetry can be implemented for example by an excentric support or by lever partial sections having different lengths.
A combination of diverting and deflection device can be implemented for example by a cam disk, the diameter of which is continuously increasing in movement direction in order to enlarge the movement, or the diameter of which continuously decreases in the movement direction in order to diminish the movement.
As an embodiment, in addition to a pure mechanical control, diverting and/or deflection device, also combinations of for example optical or electrical control devices as well as electrical, pneumatic or hydraulic diverting devices or deflection devices can be used. The optical control device can for example consist of an opacity sensor, the signal of which in turn is transformed into an electrical control value, by means of which an actuator is controlled, such as a stepping motor connected to the separation surfaces by a connection element. The actuator can be arranged so that it acts as diverting element and simultaneously by a transformation of the signal from the opacity sensor into the electrical control value and/or from the electrical control value to the stepping motor, performing the function of the deflection device.
According to a particularly advantageous embodiment or in the separation device according to claim 11, the surface of the separation surface or the separation device is at least partially coated with a functional layer. In this embodiment it is not required that the separation device or the separation surface is moved, these can also be stationary or moveable by a different device than the control device. The functional layer is a structured layer, an anti-adhesive layer, a biologically effective layer and/or a chemically effective layer. Or advantageously at least one layer comprising a combination of one or more of these functions. In an embodiment the surface of the lamellae is at least partially coated with nanoparticles or the material for the lamellae is selected for example including or of polytetrafluorethylene, so that the adhesive forces between the substances in the liquid to be cleaned and the lamellae is minimized.
Thereby the cleaning of the lamella surface is supported by gravity or the sedimentations can automatically slip off.
In a further alternative or additional embodiment the surface of the at least one separation surface (e.g. lamellae or material for the lamellae) is coated with a biocide effective substance, for example silver ions, or is doped to avoid and minimize microbial fouling on the surface of the lamellae.
The structured surface for example is a coating with particles in nanosize, wherein the particles include biologically and/or chemically active particle elements or are formed of those. By means of the so-called nanoparticles the surface characteristic (e.g. lotus effect) is influenced. By means of this effect the adhesive forces between the surfaces and sedimentations are substantially altered and also the flow along the surface is modified, e.g. the slip off of fluid layers. Both effects can be used in an embodiment of the device for the improved cleaning of the separation surfaces. By means of the alteration of the surface potentials the adhesive forces between the sedimentations and the separation surface are minimized, and by means of the influence of the border layer forces a slip off of the sedimentations in the cleaning position is benefited. For improving the slip off in the cleaning position the surface structure can be formed scale-like.
The separation of solids from a liquid is considerably influenced by the suspension characteristics. From a particle diameter of 150 μm a suspension can be seen as being stable so that solely by means of flat surfaces no separation can be achieved anymore. These suspensions having high silt fractions and in connection thereto with particle sizes smaller than 150 μm exist however just in the field of the rain water seepage. That's why in another embodiment of the method the composite arrangement of the separation surfaces is set forth, wherein the composite arrangement of the separation surfaces can be carried out separable or inseparable. For an efficient separation of solutes at least one separation surface of one composite material is used, which is mounted at least at one side, preferably on the lower side in relation to the horizontal, and at least one support layer which is capable due to its physical-chemical characteristics to receive particulate micro fractions and/or solutes from the liquid.
The advantage of the separable assembly is the subsequent adaptation of the separation surfaces to changed solid compositions in the liquid. The advantage of inseparable solutions is the assembling-friendly installation of these separation surfaces in particular at covered buildings. The at least two partial surfaces of the composite assembly differ in particular in their surface structures. The upper separation surface in vertical direction has a smooth structure to separate all particles instably located in the suspension. The further separation surface has a structured surface, such as geotextiles, to be able to separate particles stably located in the suspension.
The separation process for the stable suspension is explained in more detail on the basis of geotextiles. The geotextiles consist of different fibers, for example polypropylene, which are interwoven, needled or felted with each other. Thus a surface of geotextiles has a great specific surface, and by means of the particular manufacturing method the material has a high stopping effect as in a filter with small pressure losses. In the real separation process this surface is hit or flown through by the flow of the stable suspension wherein at the fibers of the geotextile separation surfaces the particles are separated from the liquid by means of adhesive forces and/or by means of the stopping effect of the fabric.
By means of a composite assembly of the separation surfaces only particulate substances can be mainly separated from the liquid. In a lot of liquids to be treated, however, there are also solutes, such as heavy metals, nitrate, nitrite, chloride, sulfate, organic compounds as well as metal-organic compounds etc. in the rain water. To remove these substances the separation surface has to comprise at least one active layer, for example a geotextile, plastic or foam plastic layer. These layers in turn can be removably or inseparably connected to each other. The activation of the further separation surface can for example be carried out for the removal of organic compounds form the liquid by activated carbon or activated coke. The different ion groups can be removed from the liquid by natural or synthetic ion exchanger materials. The including of the activating materials into the active layer can be carried out by coating the fibers, by fusing or by filling the porous basic material with these active substances. If only solved particles should be mainly removed, the separation surfaces can be installed in a fixed angle, wherein this angle should approximately correspond to the angle of rest of the sedimentations.
By means of the arrangement of the flow body, for example in the inflow or outflow of the basins or reservoirs the control strategy can be influenced. In the arrangement at the inflow, an advancing control characteristic is achieved, and in the arrangement at the outflow, a lagging characteristic is achieved. The advancing control characteristic should be used at small storage volume and high volume flows so that for the solid separation directly at the beginning of the filling phase or the daily hydrograph peak the greatest separation surface possible is available. In great storage volumes and small volume flows the lagging control characteristic should be used to achieve a pre-treatment by the sedimentation process during the filling phase or during the flow-through the separation device, and thus to lower the specific surface load of the lamellae, or—at unchanged surface load—to achieve the same solid value in the outflow by means of a smaller number of lamellae.
In an embodiment of the method or the device the control device comprises a perforated flow-through body, the through holes of which are partially or completely clogged up by the solids during the flow-through of the solid-loaded liquid. This enhances the build up of a pressure difference resulting in a movement of the flow-through body, which in turn is used for a change of the position of the separation surfaces.
In a further embodiment the control device comprises a channel in which the solid-loaded liquid passes by an opening of the connection element, wherein the connection may be a tube ending up at one side of a pressure unit having at least two pressure chambers and the pressure chambers of which are separated by an elastic membrane, wherein the second pressure chamber is connected for example to the ambient pressure, so that depending on the flow velocity in the channel a pressure difference is generated in the pressure unit and thereby a deflection of the membrane is caused, which is used for changing the position of the separation surfaces.
Particularly advantageously or additionally the flow velocity and/or the solids content of the liquid is detected by a mechanical, electrical, optical, pneumatic or hydraulic sensor, and the flow energy is transformed into a movement change in a mechanical, electrical, pneumatic or hydraulic way, which is used for a position change of the separation surfaces.
Advantageously the separation surfaces can be moved between their at least two positions in time-discrete steps, for example change with a dwell time of 30 minutes in the separation position and 5 minutes in the cleaning position.
A connection element between the control device and the separation device is for example a chain, a rope or rods as well as a deflection device or a diverting device which for example consists of an asymmetrically acting lever, which enlarges the change of the control device and transforms the change to the separation surfaces of the separation device for the position change.
For the use of the separation device in the wastewater treatment, in addition to the particulate mineral solids, there are also contained lightweight substances, such as fats and oils, as well as fibrous, mostly organic solids in the liquid. To remove these substances from the liquid it is advantageous to combine the separation device according to claim 20 in a separation arrangement with at least one mechanic pre-cleaning stage, such as a rake, and/or at least a further stage for the separation of emulsified and/or coagulated lipophilic substances. By means of the mechanic pre-cleaning stage the fibrous and/or lumpy, mostly organic solids can be removed from the liquid depending on the size of their through holes. The stage for the separation of the lipids and lipoid substances may for example be constructed as a grease trap, in which air is for example blown into in order to decrease the medium density and to alter the surface tension of the liquid so that these substances float onto the liquid surface and can be removed. The arrangement of the at least three stages is arbitrary and depends on the ratio of the different solid fractions of the liquid to be treated. In the wastewater cleaning the stages could be employed due to the general wastewater composition for example in the order: mechanic pre-cleaning, grease trap and separation device.
Advantageously the separation device is used with at least one stage for the separation of solved and/or unsolved lipids or lipoid substances the separation performance of which is for example increased by diminishing the medium density of the liquid, for example by the inflow of air via a ventilation rail, and/or is combined with at least one stage for the separation of coarse substances which mainly separates particulate substances having a greater equivalent diameter than the separation device, for example by a rake, wherein the individual stage can be arranged before or after the separation device.
In a further embodiment the separation device is combined with at least one stage for separating or retaining solved molecules and/or suspended micro organisms or micro organism agglomerates, wherein the separating or the retaining can be carried out for example by membranes.
In wastewater cleaning the so-called sludge activation method for cleaning the liquid is very frequently used. The sludge activation method is characterized in that suspended micro organisms in a reservoir or basin come into contact with solved and/or particulate liquid substances and transform them in biochemical way. To permanently maintain this process the micro organisms have to be separated again from the liquid at the end of the cleaning process. This separation is very cost-intensive, as it is carried out in special high-volume basins, so-called final sedimentation basins. By employing the separation device these basins can be made smaller and thus the entire process can be carried out more cost-efficient.
For a combination of the separation device with a membrane method, as set forth in an embodiment, the liquid can yet be cleaned up to the molecular range of contaminants and micro organisms. The cleaning effect and the throughput can be determined by the pore areas of the membranes. The arrangement of both stages (separation device and membranes) is arbitrary, wherein preferably the solids should be removed by the separation device in the macroscopic range and then through the membrane in the microscopic range.
The invention is explained on the basis of the following drawings, which show:
a and 4B schematic diagrams of a first and second alternative of a further combined control/separation device having two different constructive embodiments,
In an embodiment the angle α can be smaller or even negative, for example be in the range of ±10°, preferably ±5°, around the vertical. In a maximum deflection the angle β is preferably within the range of 30° to 90° to the vertical, advantageously in the range of 40° to 60°. In an embodiment the hub or the rotation angle of the separation device 9 in the cleaning position and/or in the separation position are limited by a stopper. The control device can be adjusted so that the separation device pivots back and forth nearly binary between the cleaning position and the separation position, as soon as a threshold value of the flow-through velocity of the inflowing liquid is exceeded. Or the position of the lamellae 7 changes continuously or steadily depending on the flow-through velocity. Correspondingly, these embodiments are offhand applicable also in the separation devices described below.
In the separation device 9 the lamellae are rotatably supported at their upper end and connected to each other by a holding bar 8 at their lower end. After the solid-loaded liquid is cleaned after flowing through the separation device, it leaves the basin via an outflow channel 2.
As described above, the individual lamellae 18 are connected to a connection element 8 (here bar) so that it is sufficient, if the second connection element is connected to one of the lamellae or to the connection element. By means of the liquid pressure the flow body 9a dodges and transfers its position or deflection via the first connection element 6 to the lamellae 18. If the liquid pressure decreases, a buoyancy force is generated by the low medium density of the flow body 9a as compared to the surrounding liquid, which causes a retraction of the lamellae via the second connection element 6a.
A similar embodiment shows
In
In the alternative shown in
In an embodiment the flow is directed to only one or a portion of the separation surfaces or lamellae and the remaining separation surfaces or lamellae of the separation device are mechanically coupled to that hit by the flow, so that all lamellae also carry out the pivoting movement of the lamellae hit by the flow.
A further alternative (
In a not shown embodiment of the described separation devices the first lamella, seen from the flow direction, is provided with at least one lever, the pivoting point of which is above the liquid level and which is connected to the control device or coupled to it, so that by the ratio of the lever arms around the pivoting point a smaller, an unchanged or a greater angle change of the lamellae in relation to the movement of the control element in the control device can be achieved.
In a further embodiment of the above arrangements at least one raised part is arranged on the individual lamellae, for example in form of knob or a support arm, on which the lamellae subordinated in flow direction can be supported, wherein the end of the raised part, on which the subsequent lamella lies, is formed so that during the adjustment the angle is approximately equal for all lamellae, so that by the adjustment of the first lamella in flow direction the entire lamella package can be adjusted.
The liquid to be treated, for example municipal wastewater, is fed in the alternative of
The separated particulate mineral components of the wastewater, such as sand, are collected in the lower part of the lamella separator module and are removed from the system 100 by a discharge device or a discharge element 110, for example a transport screw. The mechanically pre-cleaned wastewater overflows into the outflow channel 111 and leaves the compact system.
The alternative of
The alternative shown in
The use of functional layers at the separation device is also then advantageous, when the separation surfaces of the above shown separation devices are not moved by means of the described control device. For example, if the separation surfaces are stationary or are changeable in their position or alignment by means of operation elements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2005 004 230.9 | Jan 2005 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2006/000709 | 1/27/2006 | WO | 00 | 6/27/2008 |
