Structure and method for separating and discharging screened material from wastewater

Abstract

The invention relates to a structure (11) for separating and discharging screen material (1) from wastewater (2) flowing through the structure (11), wherein the structure (11) comprises a screening device having a screening surface (3) through which the wastewater (2) flows when the screening device is in operation and by means of which the screen material (1) entrained in the wastewater (2) is at least partially retained. According to the invention, the structure (11) comprises at least one sensor (7) which is designed to monitor the screen material (1) in the area upstream of the screen surface (3) and / or in the area of ​​the screen surface (3), and the structure (11) comprises a controller (8) which is designed to generate an alarm when the screen material has one or more defined properties that can be detected by means of the sensor (7). Furthermore, a method for driving a corresponding structure (11) and a system comprising the structure are proposed.

Description

Technical Field

[0001] The invention relates to a structure for separating and discharging screening material from wastewater flowing through the structure, wherein the structure comprises a screening device with a screening surface through which the wastewater flows when the screening device is in operation and through which the screening material entrained in the wastewater is at least partially retained.

[0002] Furthermore, a system for treating wastewater is proposed, which comprises the above-mentioned structure and at least one device connected downstream of the structure for treating screened material retained by the structure.

[0003] Finally, the present invention also relates to a method for operating a structure for separating and discharging screened material from wastewater flowing through the structure, wherein the structure comprises a screening device with a screening surface, through which the wastewater flows when the screening device is in operation and with the help of which the screen surface at least partially retains the screened material entrained in the wastewater. Background Art

[0004] Corresponding screening devices are already known in the prior art, which are used, for example, to remove coarse screening material (wood fragments, stones, etc.) from wastewater flowing into a wastewater channel. For this purpose, the screening device is usually integrated into the wastewater channel in such a way that the screening surface extends upwards vertically or slightly inclined from the channel bottom. In order to be able to discharge the screening material that is retained by the screening grid (which forms the screening surface), the screening surface usually extends beyond the maximum expected water level.

[0005] By cyclically driving the removal elements, which are attached to the screen surface and operated by the drive, the screened material is finally conveyed along the front side of the screen surface upward in the direction of the outlet, where it is removed from the removal element or elements by means of a discharger, for example.

[0006] Such a screening device is for example used in conjunction with DE 10 2012 103 058 A1. Figure 1 Give a description. Summary of the invention

[0007] The object of the present invention is to provide a structure with a screening device, a system for treating wastewater comprising the structure, and a method for driving a structure with a screening device.

[0008] This object is achieved by structures, systems and methods having the features of the independent claims.

[0009] According to the invention, firstly, a structure is proposed for separating and discharging screening material from wastewater flowing through the structure. The structure is preferably integrated in a local wastewater channel or is provided for such a wastewater channel and comprises a screening device with a screening surface, which in particular has a plurality of screening bars arranged side by side. In any case, during operation of the screening device, the screening surface is flowed through by wastewater, wherein screening material carried by the wastewater (for example stones, wood or plastic substances) is retained if it has a certain minimum size, wherein the minimum size depends on the size of the screen holes of the screening surface or the spacing of the screen bars from one another.

[0010] In order to remove the trapped screening material from the screening surface and convey it along the outlet, the screening device can include at least one removal element which is moved periodically or continuously along the screening surface by means of a drive of the screening device, for example an electric motor.

[0011] Alternatively, the screen surface can also be configured to be movable, so that the screened material can be loosened from the screen surface by the movement of the screen surface. For example, these screen surfaces can be configured by a screen drum, which is partially immersed in wastewater, wherein wastewater flows into the screen drum through the end side.

[0012] During the operation of this arrangement, it may happen that the screening material reaches an area of ​​the screening device which, due to its shape, size, weight or its material or other properties, could damage the screening device or cause it to malfunction. If, for example, an oversized branch or a life ring made of plastic is caught by the removal element or discharge device (e.g. a conveyor screw) and conveyed into the outlet area, the screening material may get stuck there, so that the subsequent screening material can no longer be conveyed out.

[0013] In order to avoid this, according to the invention, the arrangement now comprises at least one sensor in addition to the screening device. The sensor is designed so that the screened material is monitored in the upstream region of the screening surface, i.e., for example, in a section of the wastewater channel which is located in front of the screening device as seen in the flow direction of the wastewater. Additionally or alternatively, at least one sensor can also be provided which is designed to monitor the screened material in the region of the screening surface, i.e., to monitor the region in which the screened material is already in contact with the screening surface.

[0014] The sensor is preferably located at a position which is above the maximum expected wastewater level. The sensor is preferably fastened to a wall of the wastewater channel or to the screening device itself.

[0015] Furthermore, it is provided that the arrangement comprises a control unit which is designed to generate an alarm when the screening material has one or more defined properties, wherein the property or properties are detected by means of the sensor or sensors.

[0016] As characteristics of the screened material, one or more of the following characteristics can be identified with the aid of the sensor: the position of the screened material relative to a cleaning element in contact with the screened material, the size, shape, material, height, width, length, density or reflective properties of the screened material, the number of individual screened materials approaching the screening device per unit time.

[0017] Furthermore, it should be noted that the individual properties do not have to be detected directly by the sensor. Instead, it can also be provided that the sensor provides an analog or electronic signal to a control unit or a computing unit, wherein the resulting property is calculated or determined from the signal by the control unit or the computing unit.

[0018] It is particularly advantageous if the sensor is designed as a camera and the arrangement comprises a computing unit which is designed such that the signal provided by the camera is processed, preferably by means of image processing software, and thus one or more properties of the screening object are determined.

[0019] The camera can be a camera which can detect visible light, infrared light or UV light.

[0020] The camera can also be referred to as a so-called TOF camera. A TOF camera is a 3D camera system that measures the distance using the time of flight method (English: time of flight, TOF, also called ToF). After the use of PMD sensors, they are also called PMD cameras (PMD sensor = photon mixing sensor, also called PMD detector, PMD is the abbreviation of photon mixing device). For this purpose, the scene is illuminated by means of light pulses and the camera measures the time required for the light to reach the screen and return for each image point of the screen. The required time is proportional to the distance. The camera therefore provides the distance of the screen part imaged on it for each image point and thus provides the surface contour of the screen in the result and thus again provides specific properties of the screen.

[0021] Of course, the structure can also have a plurality of sensors, which may have different structures.

[0022] And the controller does not have to be part of the screening device. Instead, it can be placed at a location remote from the screening device, such as being only in active connection with the screening device via a remote connection (e.g., via the cloud).

[0023] The arrangement in any case comprises sensors, by means of which one or more properties of the screened material can be detected or monitored. The controller thus receives information by means of which it can be estimated whether the screened material that is about to touch the screen surface or has already touched the screen surface is a hazard to the screening device. This information can be transmitted, for example, to an operator of the arrangement.

[0024] A warning issued by the control unit is in particular an optical or acoustic signal (e.g. generated by a warning light or a loudspeaker). It is also conceivable that the warning is present only as an analog or electronic signal, which is evaluated by another unit (e.g. a smartphone or other computing unit). The warning can also be output as a file, image and / or movie, which is displayed on a display which in turn is a component of the structure or an external device (e.g. a smartphone or tablet).

[0025] In addition, the sensor can be constructed to detect visible light, IR light or UV light. The sensor can be constructed as an infrared sensor or a UV sensor. It is also conceivable that the sensor is constructed as an ultrasonic sensor or a sound wave sensor, which detects sound waves in the audible range. It is also conceivable that the sensor is constructed as a radar sensor (Radar = Radio Detection and Ranging; radar sensors work by emitting electromagnetic waves and evaluating echoes), a Lidar sensor or a laser sensor. Lidar stands for laser radar and refers to a method in which light (for example, a wavelength of 905nm) is emitted and the distance can be calculated by the running time and the speed of light. To be precise, a laser sensor (for example in the form of a laser scanner) is also a Lidar sensor or works according to the Lidar principle. However, this name is often used to characterize sensors that work with the help of diodes and rotating mirrors.

[0026] It is also advantageous if the arrangement has at least one light source, by means of which the screen material is illuminated upstream of the screen surface (with respect to the flow direction of the wastewater passing through the screen surface) and / or in the screen surface region in which the screen material contacts the screen surface, if the light source is switched on. The light source can be a light source that emits visible light, ultraviolet light (UV light) or infrared light (IR light) during operation. In particular, the light source can be a component of the sensor if the sensor is designed as a camera. It is also conceivable that the sensor and the light source are separate units.

[0027] Additionally or alternatively, the sensor can be configured to detect sound waves, which are generated by the sound source of the structure and reflected by the screened material. The measured values ​​provided by the sensor can be evaluated again by means of a controller or a corresponding computing unit and one or more characteristics of the corresponding screened material can be derived therefrom.

[0028] The screening device preferably comprises at least one removal element which can be moved along the screening surface by means of a drive of the screening device in order to remove the screening material caught by the screening surface from the screening surface and convey it in the direction of the outlet of the screening device. In this case, the screening surface is formed by a plurality of screening bars arranged side by side. These can be designed to be straight or curved.

[0029] It is also advantageous that the controller is constructed in such a way that, when the screened material has one or more defined characteristics and identified by means of the at least one sensor, the drive is stopped, which moves the cleaning element or elements. It is also conceivable that if the screened material driven on the screen surface or caught by the cleaning element has a spatial dimension higher than a threshold value, the drive is stopped or suppressed (i.e., slowed down). If the screened material caught by the cleaning element is in a range outside the limited spatial range on the cleaning element, the suppression and stopping of the drive are also advantageous. The drive stops in this case to avoid the screened material being tilted or stuck in or inside the screening device.

[0030] In contrast to the prior art, the function or possible malfunction of the screening device is not (only) detected. Instead, the arrangement with sensors comprises an element which is suitable for collecting information about screening material approaching the screening device or already located in the area of ​​the screening surface, which information is suitable for predicting a possible malfunction of the screening device. If screening material with one or more defined properties is detected, the arrangement can prevent the corresponding malfunction in a preventive manner by emitting an alarm or stopping the removal element or elements (or stopping the screening surface if the screening surface is designed to be movable).

[0031] Alternatively, it is also conceivable that the controller only issues an alarm, which informs the operator of the arrangement that a screening material having one or more undesirable characteristics is approaching the screening surface or has come into contact with the screening surface. In addition, the alarm can also include information that the movement of the removal element or elements should be stopped or their delivery power should be suppressed to prevent damage to the screening device or malfunctions.

[0032] Advantageously, the screening device has a discharger. The discharger is preferably located in the upper region of the screening device or the screening surface and serves to discharge the screening material from the removal element or elements in the outlet region. The discharger is preferably spring-loaded and rests against the removal element as the removal element passes by. The removal of the respective screening material is achieved by the relative movement between the removal element and the discharger. The screening material finally leaves the screening device through the outlet.

[0033] It is now preferably provided that the discharger can be moved between a discharge position and a passing position, preferably swiveled about a swivel axis, by means of a drive mechanism of the screening device. In the discharge position, the discharger assumes a position in which it contacts a passing removal element, and in the passing position, the discharger is positioned such that a minimum spacing of at least 10 cm, preferably at least 20 cm, exists between the discharger and a passing removal element.

[0034] If the screening material passing the sensor now has one or more specific properties that could cause mechanical damage to the discharger or the removal element or elements or lead to malfunctions of the discharger, the discharger is brought into its passing position. In this case, the corresponding screening material can pass through the discharger and finally fall by gravity from the removal element that transports the screening material.

[0035] Furthermore, the signal of the sensor or sensors can be used to control a device connected downstream of the arrangement or to influence its operation. The device is preferably a device by means of which the screened material removed from the wastewater by the screening device is further processed. The device can be, for example, a drying device or an extruder, which serves to reduce the moisture content of the screened material by an extrusion process.

[0036] In particular, it is provided that the device has a machine controller which is in an operative connection with the structure, wherein the machine controller is designed such that the device is controlled taking into account the signals provided by the sensors of the structure. It is also conceivable that if the screening device is also stopped, the operation of the device is also stopped. The machine controller can stop automatically. Depending on the screening material characteristics detected by means of the sensor or sensors, the conveying power or drying power of the device can also be changed.

[0037] Accordingly, the present invention also provides a system for treating wastewater, which comprises the above and / or below described structure and comprises at least one device connected after the structure for treating the screened material blocked by the structure.

[0038] In addition, the present invention also relates to a method for operating the structure for separating and discharging screening material from wastewater flowing through the structure. The structure preferably refers to a structure having the above and / or following features, wherein the individual features can be realized in any combination.

[0039] The arrangement comprises in particular a screening device having a screening surface through which the wastewater flows when the screening device is in operation and by which the screening material carried in the wastewater is at least partially retained. The screening device also preferably has at least one removal element which is at least occasionally moved along the screening surface in order to remove the screening material retained by the screening surface from the screening surface and convey it in the direction of the outlet of the screening device.

[0040] Finally, it is provided that the arrangement also comprises at least one sensor. The screened material is monitored by means of the sensor in the region upstream of the screen surface or in the region of the screen surface, wherein an alarm is output when the screened material has one or more defined properties that are detected by means of the sensor. For possible sensors or conceivable alarm types, please refer to the description.

[0041] The method is characterized in that the screen is monitored by means of at least one sensor, wherein one or more properties of the screen being monitored are inferred therefrom. The properties that can be monitored are mentioned in other parts of the description.

[0042] The sensor can detect whether the screen material approaches the screening surface or has been caught by a removal element which has one or more properties which prevent further transport of the screen material to the screening device outlet or which during transport can cause mechanical damage or malfunctions of the screening device.

[0043] By sounding the alarm, the operator of the structure or its controller is informed that the screening device is in danger. The operator can finally operate accordingly, for example, stop the removal element and manually remove the corresponding screening material from the screening device.

[0044] It is also advantageous if the sensor is designed as a camera, the signal of the camera is processed by means of image processing software and one or more characteristics of the screening object are determined thereby. The software can be a component of the controller. It is also conceivable that the signal of the camera can be transmitted to a separate computing unit (e.g. a laptop, a tablet or a smartphone) and evaluated there. With the aid of the image processing software, one or more characteristics can be identified, such as the spatial size, shape and position or type of the screening object.

[0045] It is particularly advantageous to transmit the signal of the camera at least occasionally and in the form of a single image or in the form of a film to a display of the structure or an external display, such as a smartphone. In this case, the screening device can be monitored from a location where it is not directly visible. For example, it is also conceivable to transmit the signal or the properties of the screened material inferred therefrom to a control center of the operator of the structure, which is arranged remotely from the screening device.

[0046] It should also be noted that the screening device can have a screening surface, which is formed by a screen drum running around an axis of rotation, wherein the screen drum is immersed in the wastewater so that the wastewater flows into the screen drum through the end side of the screen drum. In this case, the screened material held up by the screen drum is removed, for example, by means of a conveying screw.

[0047] It is also advantageous that if the screening material has one or more defined characteristics, the controller proposes to the operator of the structure whether to stop the operation of the screening device or suppress its delivery power, or whether to stop this or these removal elements or suppress its movement. If one or more characteristics of the screening material have been identified, it can be inferred that problems will occur when the screening device is running, especially when the screening material is transmitted through this or these removal elements, then the alarm can include suggestions to the operator, that is, the drive of this or these removal elements should be stopped, or the operation of the drive should be slowed down to avoid damage to the screening device. Additionally or alternatively, the alarm can include such suggestions, that is, stop the screening device or suppress its delivery power (i.e., the screen material discharged in each time unit).

[0048] It is also advantageous if the controller, when issuing a suggestion, takes into account whether one or more of the suggestions provided to the operator have already been considered by the operator. If the controller knows from past experience that the operator has not translated a suggestion to stop the removal element or elements into actual action, it can be provided that this suggestion is not to be made in the future if the characteristics of the screened material are within a certain range. The controller can thus be designed to learn autonomously and can adapt itself based on the operator's behavior.

[0049] Generally speaking, it is advantageous that the controller takes into account the operator's previous behavior when evaluating the signal of the sensor(s). The limit value of the sensor(s) can also be changed over time, an alarm being sounded and / or the drive of the removal element(s) being stopped or inhibited when reaching, exceeding or falling below the limit value(s).

[0050] It is particularly advantageous to take into account external data such as climate or weather data (e.g. rainfall forecasts), social events (e.g. festivals in a region whose wastewater is to be directed to the structure according to the invention) or the calendar (e.g. season) when deciding whether to issue an alarm. Based on these data, for example, other operators can be assigned to the structure in order to more quickly remedy more or less frequently expected critical states of the structure.

[0051] It is also advantageous if the controller stops the removal element or slows down its movement if the screening material monitored by the at least one sensor has one or more defined properties, wherein the movement is stopped before or after the respective screening material comes into contact with the screening surface. Additionally or alternatively, the movement of the screening device can also be stopped or its delivery capacity can be suppressed.

[0052] It is most advantageous if the signals provided by the sensor and / or the properties detected by means of the sensor are stored in a database and evaluated with respect to predefined characteristic values. It is also conceivable, for example, to count the presence of specific properties of the screened material or their temporal changes. Anomalies can thus be detected quickly and the arrangement can be quickly adjusted, including, for example, changes in the conveying speed of the removal element or elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Other advantages of the present invention are described in the following embodiments. They are schematically shown respectively:

[0054] Figure 1 A system according to the invention is shown, comprising a structure according to the invention for separating and discharging screenings from wastewater;

[0055] Figure 2a A cutout of a screening device according to the invention is shown in a top view; and

[0056] Figure 2b The cutout of the screening device according to the invention is shown in a top view, with the position of the screening object being changed. DETAILED DESCRIPTION

[0057] It should be noted in advance that in the figures showing a plurality of similar components or sections (eg the cleaning element 4 ), only one or two of the plurality of similar components or sections are provided with a reference number in order to ensure a good overview.

[0058] Figure 1 An arrangement 11 according to the invention is shown which is integrated in a wastewater channel 19 and which serves to separate and remove screening material (in the form of, for example, stones, branches, etc.). The arrangement 11 comprises a screening device having a screening surface 3 (in the form of a screening grid) which projects obliquely from above into the wastewater 2 and which is connected to a support of the screening device and, if necessary, to the channel bottom of the wastewater channel via fastening elements (not shown). The screening surface 3 preferably comprises a plurality of screening bars 9 arranged side by side (cf. Figure 2a , 2b , which show a top view of a cutout of a corresponding screening device).

[0059] The arrangement 11 also has traction means 17 (e.g. in the form of a drive chain) arranged one behind the other relative to the drawing, spaced apart from one another, which can be moved in a circular manner in front of the screen surface 3 in the flow direction of the wastewater 2 by means of a drive 5, which are connected to one another via a centrally located removal element 4 (here one removal element 4 is also sufficient). The traction means 17 are guided in their tracks by lateral guides (not shown), wherein the guides can be located in the upper and lower deflection regions, but also in the central region, in which the traction means 17 extend parallel to one another.

[0060] These cleaning elements preferably include a large number of cleaning teeth 21 arranged side by side. If the cleaning element 4 is driven by the traction mechanism 17 along the conveying direction (relative to the Figure 1 The cleaning teeth are then swept from the front side of the screen surface 3 in a counterclockwise direction, and then embedded in the middle cavity of the screen surface 3 (compare Figure 2a and 2b ).

[0061] The screened material 1 (at Figure 1 In the embodiment of the present invention, the waste water flows from left to right in the waste water (in the process of the present invention), and is finally caught by the cleaning element 4 or its cleaning teeth 21 and conveyed upward. After passing the upper turning point, the waste water finally reaches the area of ​​the outlet 6, possibly with the help of the discharger 20 shown, but not absolutely necessary, and from there to the outside, for example, into a container. The cleaning elements 4 are finally guided again to the next turning point, so that the cycle starts from the beginning.

[0062] It should be noted that the movement path of the removal element(s) 4 does not necessarily have to extend completely in front of the screening surface 3 (with respect to the flow direction of the wastewater 2). Embodiments not shown are also conceivable in which the removal element(s) 4 in the side view shown "circle" the screening surface 3 (the removal elements 4 in this case move in front of the screening surface 3 together with the screening material 1 and move behind the screening surface 3 without the screening material).

[0063] Also like Figure 1 As shown, a device 14 for treating the screened material 1 can also be arranged after the screening device or the structure according to the invention 11, which structure, in addition to the screening device, also includes at least one of the above-mentioned sensors 7. The device 14 can be designed, for example, as a squeezer or a drying device (centrifuge, solar dryer) for reducing the moisture content of the screened material 1 leaving the screening device. The screened material 1 can be conveyed to the device 14, for example, by means of a conveyor belt 18, which together with the structure according to the invention forms a system for treating the wastewater 2.

[0064] The device 14 preferably has a machine control 15 which is connected to the control 8 of the screening device or the structure 11 or to the computing unit 10 thereof.

[0065] According to the invention, the arrangement 11 comprises one or more sensors 7, by means of which one or more characteristics of the screened material 1 flowing onto the screen surface 3 in the wastewater 2 or of the screened material already in the range of action of the removal element 4 can be detected.

[0066] With regard to possible features or possible properties of the sensor 7 , reference is made to the description.

[0067] It is generally conceivable that the sensor 7 is located on the screening device, or Figure 1 The wall shown is located on the wastewater channel 19, in which the screening device is integrated. Figure 1 In FIG. 5 , the sensor 7 is designed as a camera, wherein the field of view of the camera is indicated by two dashed lines.

[0068] The sensor 7 is also in operative connection with the controller 8 or its computing unit 10 of the arrangement 11. In addition, the arrangement 11 can also include a display 16 on which the alarm can be displayed if the monitored characteristics of the screening material 1 meet certain criteria. The display 16 can also be a component of a remote control device (e.g. a smart TV).

[0069] It is also conceivable that, if the screening material 1 has certain properties, the discharger 20 is moved into a passing position by means of the drive mechanism 12 in order to avoid unnecessary collisions between the screening material 1 and the discharger 20 .

[0070] Figure 2a Now a top view of a cutout of the structure 11 according to the invention is shown. As can be seen in this figure, screening material 1 in the form of branches has been caught by the screening surface 3, which is formed by a plurality of screening bars 9, and is now caught by the removal element 4.

[0071] If the branch is now directed upwards and ultimately towards the outlet 6 , no problems arise.

[0072] Otherwise, the situation shown in FIG. 2 would occur. In this case, a part of the branch is outside the removal element 4, and there is a risk that the branch will get stuck between the removal element 4 and the wall or other section of the screening device during the continued movement of the removal element. The monitored characteristic in this case can therefore be the position of the screening material 1 relative to the removal element 4.

[0073] If it is now detected that this position does not correspond to the default position for trouble-free operation of the structure 11 , an alarm is output and the drive 5 is possibly stopped.

[0074] It is also conceivable to also stop the downstream device 14 or its delivery capacity.

[0075] As a result, the invention provides for monitoring certain properties of the screened material 1 and, on the basis of these properties, issuing an alarm or adjusting the operation of the structure 11 or the device 14 in order to avoid malfunctions and damage.

[0076] The invention is not limited to the embodiments shown and described. Even if any combination of the described features is shown and described in different parts of the description or claims or in different embodiments, variations within the scope of the claims are possible as long as they do not conflict with the teaching of the independent claims.

[0077] Reference Mark List

[0078] 1 Screening

[0079] 2 Wastewater

[0080] 3 Screen surface

[0081] 4 Clear components

[0082] 5. Driver

[0083] 6 Exit

[0084] 7 Sensors

[0085] 8 Controller

[0086] 9 Screen rod

[0087] 10 Computational Units

[0088] 11 Structure for separating and discharging the screened material

[0089] 12 Drive Structure

[0090] 13 Systems for removing dirt from wastewater

[0091] 14 Equipment for handling screened material

[0092] 15 Machine Controller

[0093] 16 Display

[0094] 17 Traction mechanism

[0095] 18 Conveyor belt

[0096] 19 Wastewater Channel

[0097] 20 Unloader

[0098] 21 Clean teeth.

Claims

1. A structure (11) for separating and discharging screened material (1) from wastewater (2) flowing through the structure (11), wherein the structure (11) comprises a screening device having a screen surface (3), through which the wastewater (2) flows when the screening device is in operation and by means of which the screen surface at least partially retains the screened material (1) carried in the wastewater (2), the screen surface having a plurality of screen bars arranged side by side, the screening device having at least one removal element (4) which can be moved along the screen surface (3) by means of a drive (5) of the screening device in order to remove the screened material (1) retained by the screen surface (3) from the screen surface and discharge it in the direction of an outlet (6) of the screening device, It is characterized in that The structure (11) comprises at least one sensor (7), which is arranged on the screening device and is configured to monitor the screened material (1) in the area of ​​the screening surface (3), the area being the area where the screened material is located when it has come into contact with the screening surface, and the structure (11) comprises a controller (8), which is configured to issue an alarm when the screened material has one or more of the following defined characteristics that can be identified by means of the sensor (7): the position of the screened material relative to the cleaning element in contact with the screened material, the size, shape, material, height, width, length of the screened material, wherein the drive is stopped or inhibited when the screened material that has been caught by the cleaning element has a spatial dimension that is higher than a threshold value.

2. The structure (11) according to claim 1, characterized in that The sensor (7) is designed as a camera, and the arrangement (11) comprises a computing unit (10) which is designed to process the signal provided by the camera by means of image processing software and thereby to determine one or more properties of the screening object.

3. The structure (11) according to claim 1, characterized in that The sensor (7) is configured as a radar sensor, an infrared sensor, a lidar sensor, an ultrasonic sensor or a laser sensor.

4. The structure (11) according to any one of the preceding claims, characterized in that The structure (11) has at least one light source, by means of which the upstream region of the screening surface (3) and / or the screening material (1) in the region of the screening surface (3) is illuminated if the light source is switched on.

5. The structure (11) according to claim 4, characterized in that The control unit (8) is designed in such a way that the drive (5) is stopped or inhibited if the screening material (1) has one or more defined properties that are detectable by means of the at least one sensor (7).

6. The structure (11) according to claim 5, characterized in that The screening device has a discharger, by means of which the screening material (1) is discharged from the removal element or elements in the region of the outlet (6) if the removal element or elements (4) are moved, wherein the discharger (20) can be moved between a discharge position and a passing position by means of a drive mechanism (12) of the screening device.

7. A system for treating waste water (2), comprising a structure (11) according to any one of the preceding claims and comprising at least one device (14) connected downstream of the structure (11) for treating the screening material (1) retained by the structure (11), It is characterized in that The device (14) has a machine control (15) which is operatively connected to the structure (11), wherein the machine control (15) is designed to control the device (14) taking into account signals provided by the sensor (7) of the structure (11).

8. A method for operating a structure (11) as claimed in any one of the preceding claims for separating and discharging screening material (1) from wastewater (2) flowing through the structure (11), wherein the structure (11) comprises a screening device with a screening surface (3) through which the wastewater (2) flows when the screening device is in operation and through which screening material (1) entrained in the wastewater (2) is at least partially retained, It is characterized in that The arrangement (11) comprises at least one sensor (7), wherein the screen material (1) is monitored in an area upstream of the screen surface (3) and / or in the area of ​​the screen surface (3) by means of the sensor (7), and an alarm is output if the screen material (1) has one or more defined properties which are detected by means of the sensor (7).

9. The method according to claim 8, characterized in that The sensor (7) is designed as a camera and the signals of the camera are evaluated by means of image processing software and one or more properties of the screening material (1) are determined therefrom.

10. The method according to claim 9, characterized in that The signal of the camera is transmitted at least occasionally and in the form of a single image or in the form of a movie to a display of the structure (11) or to an external display (16).

11. The method according to any one of claims 9 to 10, characterized in that The screening device has at least one removal element (4) which is at least occasionally moved along the screening surface (3) in order to remove screening material (1) held back by the screening surface (3) from the screening surface and convey it in the direction of an outlet (6) of the screening device.

12. The method according to claim 11, characterized in that If the screening material (1) has one or more defined properties, the control unit (8) makes a recommendation to the operator of the structure (11) whether the operation of the screening device should be stopped or its delivery capacity should be reduced and / or whether the movement of one or more removal elements should be stopped or reduced.

13. The method according to claim 12, characterized in that The controller (8) should consider, when issuing a suggestion, whether one or more of the suggestions provided to the operator have been considered by the operator.

14. The method according to claim 13, characterized in that Consider external data when deciding whether to issue an alert.

15. The method according to claim 14, characterized in that If the screening material monitored by means of the at least one sensor (7) has one or more defined properties, the control (8) stops or slows down the movement of the removal element or elements (4) and / or stops the operation of the screening device or reduces its delivery rate.

16. The method according to claim 15, characterized in that The signals provided by the sensor (7) and / or the properties detected by means of the sensor (7) are stored in a database and evaluated with respect to predefined characteristic values.

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