Wastewater treatment processes and wastewater treatment plants

Abstract

The invention relates to a method for treating wastewater and a wastewater treatment plant. It is therefore an object of the invention to eliminate the disadvantages of the prior art and to provide a method for treating wastewater and a wastewater treatment plant, wherein the method according to the invention enables efficient filtration of particles such as braids and / or microplastics without significantly depleting associated organic substances and / or significantly damaging associated microbiota, and wherein the wastewater treatment plant according to the invention is adaptable to the requirements profile of various application scenarios. This problem is solved by the features listed in the claims.

Description

[0001] The invention relates to a method for treating wastewater and a wastewater treatment plant.

[0002] A wastewater treatment plant, also known as a sewage treatment plant, is a technical facility for purifying wastewater. Modern wastewater treatment plants use mechanical, biological, and chemical processes, which are applied sequentially in various treatment stages.

[0003] During the first treatment stage, which involves mechanical processes, the wastewater flows through a filter element that traps coarse particles. The filter element is typically a screen or sieve. The coarse particles, which are referred to as screenings or screenings after the solid-liquid separation, can include all types of urban waste. Fibers contained in wastewater (textile fibers, hair, paper, and plastics) are problematic. Due to their structure, they tend to become entangled and can cause damage to pumps and agitators.

[0004] Accordingly, it is necessary to efficiently separate such clumps (as well as all other particles) from the wastewater. The corresponding screenings or screenings typically have a water content of over 85% immediately after removal. Since the task of a wastewater treatment plant is to treat as much wastewater as possible so that it can be reused as industrial and / or drinking water, it is therefore necessary to dewater the screenings or screenings. For this purpose, the screenings or screenings are transferred to a dewatering device, whereby the filter element for solid-liquid separation and the dewatering device can be designed as a combined device.

[0005] A corresponding combined device is disclosed, for example, in document EP 3483126. Specifically, a wastewater treatment plant for treating wastewater is disclosed. The wastewater treatment plant comprises a screening system and a grit trap located downstream of the screening system in the direction of wastewater flow. The screening system and the grit trap separate solids of varying particle sizes from the wastewater. The wastewater treatment plant further comprises a screening device (corresponding to the filter element) located downstream of the grit trap in the direction of wastewater flow, with the aid of which the wastewater leaving the grit trap is screened. This produces primary sludge (corresponding to the screening material) and a suspension passing through the screening device. The wastewater treatment plant further comprises a thickener (corresponding to the dewatering device), with the aid of which the primary sludge leaving the screening device is thickened.In an advantageous embodiment, a mechanical thickener is arranged downstream of a static thickener, whereby the residence time of the primary sludge in the static thickener can be one to ten hours.

[0006] A disadvantage of the aforementioned state of the art is the way in which the screenings or screenings are dewatered, which usually have a water content of over 85%.

[0007] This water contains, on the one hand, organic substances that serve as a carbon source for the downstream biological treatment stage of the wastewater treatment plant. Here, for example, wastewater constituents to be removed using the activated sludge process are converted through biological processes (respiration, biomass growth) into forms that can be removed from the wastewater by sedimentation or stripping (gaseous expulsion) and are also as harmless as possible. On the other hand, the water contains a corresponding microbiota, i.e., a multitude of microorganisms that carry out the biological processes. It is therefore desirable to transfer both components to the biological treatment stage of the wastewater treatment plant with as little loss and as biologically active a presence as possible.

[0008] However, state-of-the-art wastewater treatment plants result in a significant reduction or inactivation of organic substances or the microbiota. For example, long residence times of the screenings or screenings in static dewatering devices, combined with high temperatures, lead to premature degradation of organic substances. The onset of oxygen deficiency leads to putrefaction and a corresponding shift in the microbiota. Mechanical dewatering devices create high pressure, which leads to the inactivation of at least some of the microbiota. The same applies to an unnecessarily large number of consecutive process steps, such as pumping processes, in which the microbiota is negatively affected due to high pressure and / or high shear forces.

[0009] It is therefore desirable to have a mechanical wastewater treatment plant that allows efficient solid-liquid separation, minimizing organic losses and transferring the relevant microbiota biologically actively to the biological treatment stage. Description of the invention

[0010] It is an object of the invention to eliminate the disadvantages of the prior art and to provide a method for treating wastewater and a wastewater treatment plant, wherein the method according to the invention enables efficient filtration of particles such as braids and / or microplastics without significantly depleting associated organic substances and / or significantly damaging associated microbiota, and wherein the wastewater treatment plant according to the invention is adaptable to the requirement profile of various application scenarios.

[0011] This problem is solved by the features listed in the claims.

[0012] The problem is solved by a process for treating wastewater, whereby the process for treating wastewater comprises the following process steps: a. Filtration of substances from wastewater in a sewer using a filter belt and the resulting formation of a filter cake on the filter belt b. Cleaning the filter cake by means of a water spray in such a way that small organic components are rinsed out of the filter cake and returned to the wastewater in the sewer after filtration from process step a), c. Cleaning the filter belt and removing the filter cake by brushing and / or dewatering the filter cake using a filter press.

[0013] According to various embodiments, the filter belt is a circulating endless filter belt and / or the filter press is a screw filter press.

[0014] According to various embodiments, the following variables are regulated and / or controlled by means of a control and / or regulating unit: filter belt speed, brush speed, screw press speed, water quantity and / or pressure and / or angle of inclination of the filter belt.

[0015] According to various embodiments, measured values ​​are recorded for control and / or regulation, preferably the water level in the channel, the dimensions of the resulting filter cake, the speed of the filter belt, the speed of the screw press, the flow rate in the channel, and the degree of drying of the filter cake.

[0016] The object is further achieved by a wastewater treatment plant, preferably for treating wastewater in an open channel in sewage treatment plants. The wastewater treatment plant has the following modules: at least one filter belt module, at least one spray module, at least one cleaning module for cleaning the filter belt module and / or the filter belt, and at least one control and / or regulating unit. The at least one filter belt module can be positioned at an angle in an open channel and has a filter belt for filtering out substances from the wastewater in the open channel. The filter belt is guided circumferentially over deflection rollers and is preferably an endless filter belt. When the wastewater treatment plant is in use, a filter cake is formed on the filter belt. The at least one spray module is arranged above a first part of the filter belt and serves to rinse organic components out of the filter cake.The at least one cleaning module serves to clean the filter belt module and / or the filter belt. The at least one cleaning module is arranged on a second part of the filter belt. The at least one cleaning module has a brush unit and / or a filter press to clean the filter cake from the filter belt. The at least one control and / or regulation unit is configured to control and / or regulate the modules of the wastewater treatment plant using a sensor and / or input unit.

[0017] According to various embodiments, the filter press is a screw filter press.

[0018] According to various embodiments, the at least one spray module comprises at least one water mist spray unit. The at least one water mist spray unit comprises at least one water spray nozzle.

[0019] According to various embodiments, the spray module has a pump system.

[0020] According to various embodiments, the filter belt is designed as a sandwich construction, as a single-layer construction, and / or is individually adaptable. Furthermore, the filter belt can be adapted in terms of its filter fineness and / or structure to meet the requirements of different wastewater treatment plants. Different belts can also be combined to achieve a customized filter performance. For example, a filter belt with 100 µm pores and a filter belt with 3 mm pores can be combined for the filtration of microplastics and entanglements. The filter belts can be combined one above the other (multi-layer) or in series (single-layer). The speed of the filter belt can be precisely adjusted to meet requirements.

[0021] According to various designs, the inclination angle of the filter belt module is adjustable. This allows the filter belt module to be adapted to the channels of various wastewater treatment plants.

[0022] The entire wastewater treatment plant consists of three main modules: at least one filter belt module, at least one spray module, and at least one cleaning module. Substances such as tangles in the wastewater are filtered out by the filter belt, forming a filter cake for further deep filtration of the wastewater to remove smaller particles such as microplastics. The water mist spray unit uses a very fine water mist to clean organic components bound to the filter residues, which can still be recycled by the aeration tanks. Finally, the filter belt is cleaned with a motorized brush, and the cleaned material is further dewatered with a small, built-in screw filter press.

[0023] Advantageously, the wastewater treatment plant or at least one of its filter belt modules is sealed laterally from the sewer, so that all wastewater is inevitably directed over the filter belt. Sealing can be achieved with a filter belt whose inclination angle can be adjusted, for example, using rubber lips. For this purpose, rubber lips can also be located at the lower edge of the filter belt to direct the water onto the conveyor belt. It is also conceivable to use rubber lips above and / or along the filter belt to roll the filter cake onto the filter belt.

[0024] Since, in addition to the undesirable inorganic accompanying substances, organic matter that is valuable for the aeration process is deposited on the filter belt as the wastewater flows through the channel, the at least one spray module has a gentle low-pressure rinsing device on the upper exposed guide area of ​​the filter belt of the wastewater treatment plant according to the invention. The low-pressure rinsing device serves to bring the organic components back into aqueous solution and thus separate them from the filter belt and the inorganic contaminants. In order to prevent the tangles and microplastics from also being rinsed through the relatively coarse-meshed fabric during this process, a metallic slotted or fabric sieve with a significantly lower filter fineness is arranged below the filter belt in the area of ​​the at least one water mist spray unit to prevent this from happening. Advantageously, the metallic slotted or fabric sieve isThe mesh screen is designed to be replaceable for cleaning purposes, for example, by being able to be pushed in or pulled out laterally relative to the direction of movement of the filter belt. This also allows for quick adjustment of the metal slotted or mesh screen in terms of its filter fineness by inserting a different metal slotted or mesh screen with a different filter fineness. The flushed-out organic matter penetrates the metal slotted or mesh screen in dissolved form and thus reaches the clean side of the wastewater treatment plant.

[0025] Advantageously, the at least one spray module uses the pumping system to utilize the wastewater on the clean side of the filter belt, eliminating the need for additional pumps and saving water and energy resources. The at least one spray module generates an extremely fine water mist to minimize damage to the microbial community. In a preferred embodiment, the wastewater treatment plant comprises multiple water mist spray units, each with multiple water spray nozzles, wherein each water mist spray unit can preferably be individually controlled with regard to opening and closing, water quantity, and pressure. For example, the pressure and water quantity of a lowest water mist spray unit are greatest and decrease towards (along an inclined filter belt) an upper water mist spray unit.Because the at least one spray module is physically positioned relatively far upstream of the at least one cleaning module, the filter residues on the filter belt have time to dry before reaching the at least one cleaning module. The pre-dried filter residues entering the screw filter press improve the subsequent dewatering process.

[0026] Alternatively, the pumping system can be formed by a water source available at the wastewater treatment plant's installation site, which provides water at a pressure sufficient to create a water spray using a water mist spray unit. This could be, for example, a domestic water connection, a high-pressure water connection, a hydrant, or similar. The advantage of this is that the pumping system does not require a separate water pump.

[0027] In the at least one cleaning module, real-time cleaning of the filter belt and further dewatering of the filter residue takes place with the help of at least one motorized brush and at least one integrated screw press. The brush heads of the at least one brush unit can be interchangeable depending on the nature of the filter belt and / or the size and / or composition of the filter cake, so that different materials can be used. Furthermore, the brush heads can be designed to be mobile and can be moved towards the filter belt at the start of a cleaning process. A corresponding contact pressure, to be defined, between the filter belt and the brush head can be determined using a pressure sensor. It is conceivable that several brushes are used, for example a first brush for coarse cleaning and a second brush for fine cleaning.The operation of the at least one cleaning module, with respect to the position, start / stop, and speed of the brushes, can be carried out manually or automatically by means of a control and / or regulation unit and / or sensor unit. Furthermore, the operation of the screw filter press can also be carried out manually or automatically by means of a control and / or regulation unit and / or sensor unit, comprising, for example, fill level sensors.

[0028] With the help of control programming, automated, intelligent filtration processes can be implemented that are precisely tailored to the needs of various application scenarios, from pure tangle filtration to simultaneous microplastic filtration. Each module is preferably equipped with an independent control and / or regulation unit, via which the operating parameters of individual modules can be individually adjusted. Furthermore, all control units can be programmed to work together and coordinate the corresponding operating parameters. The parameters of the filtration process can be individually adjusted, and the filtration process operates automatically depending on the water quantity, the quality of the belt, etc., as explained below as an example.

[0029] A filter belt with an exemplary fineness of 500 µm is selected, and the filter belt speed is adjusted to obtain a thicker and finer filter cake for filtration of microplastics. At the same time, the volume and pressure of the spray water toward the filter belt are reduced to preserve the filter cake longer and adequately remove the persistent organic components at the end of the filtration process. The speed of the motorized brush is increased to adequately clean the thicker cake.

[0030] Advantageously, the entire wastewater treatment plant is designed to pivot via bearings, such as pivot bearings, using a drive, such as a linear drive. In the event of an emergency, triggered, for example, by a level limit switch (Liquiphant), a sufficiently free flow cross-sectional area can be created in the sewer within a short time, thus preventing wastewater from overflowing sideways from the sewer. Implementation of the invention

[0031] The invention will be explained in more detail using an exemplary embodiment. Fig. 1 the wastewater treatment plant in schematic view, Fig. 2 a section through the wastewater treatment plant in side view.

[0032] In the description, reference is made to the accompanying drawings, which show, by way of illustration, specific embodiments in which the arrangement according to the invention may be practiced. In this regard, directional terminology such as "top," "bottom," etc., is used with reference to the orientation of the described drawings. The directional terminology is for illustrative purposes and is in no way limiting.

[0033] It is understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It is understood that the features of the various exemplary embodiments described herein may be combined with one another unless specifically stated otherwise. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0034] In the figures, identical or similar elements are provided with identical reference numerals where appropriate.

[0035] The wastewater treatment plant according to the invention is Fig. 1. The wastewater treatment plant has the following modules: at least one filter belt module, at least one spray module, at least one cleaning module for cleaning the filter belt module and / or the filter belt 3 and at least one control and / or regulating unit 6. The at least one filter belt module can be set up obliquely in an open channel 2 and has a filter belt 3 for filtering out substances from the wastewater 1 located in the open channel 2.

[0036] The filter belt 3 is preferably circulating over deflection rollers 7 (better visible in Fig. 2). Preferably, the filter belt 3 is an endless filter belt. When the wastewater treatment plant is in use, a filter cake is formed on the filter belt 3. The at least one spray module is arranged above a first part of the filter belt 3 and serves to rinse organic components out of the filter cake. The at least one cleaning module serves to clean the filter belt module and / or the filter belt 3. The at least one cleaning module is arranged on a second part of the filter belt 3. The at least one cleaning module has a brush unit and / or a filter press in order to clean the filter belt 3 of the filter cake. The at least one control and / or regulation unit 6 is configured to control and / or regulate the modules of the wastewater treatment plant by means of a sensor and / or input unit.

[0037] According to the embodiment according to Fig. 1, the wastewater treatment plant may have a pivot bearing 12, around which the wastewater treatment plant, in particular the filter belt 3, can be pivoted out of the channel 2 by means of a pivot drive 13. In the event of an emergency, triggered by an emergency system and / or by a sensor system, for example by a level limit switch (Liquiphant), a sufficiently free flow cross-sectional area can be generated in the channel 2 within a short time, thus preventing lateral overflow of the wastewater 1 from the channel 2.

[0038] According to various embodiments, the spray module preferably has four water mist spray units 8. Again, each water mist spray unit preferably has four water spray nozzles 9. The water mist spray units 8 are preferably supplied with clarified wastewater 1 from the clean side of the wastewater treatment plant (downstream of the filter belt 3 in the flow direction of the wastewater 1) by means of a pump 11 via the pump system 10.

[0039] Fig. 2 shows the wastewater treatment plant according to the invention according to Fig. 1, wherein the wastewater treatment plant comprises an enclosure 21. Such an enclosed wastewater treatment plant can be supplied with warm air from a conventional heating fan by means of a hot air connection 18 at freezing temperatures to ensure year-round use.

[0040] The filter belt 3, which can be designed as an endless filter belt, is driven by a drive roller 16, which is preferably arranged above the liquid level 20 of the wastewater 1. Depending on the amount of dirt and the desired height of the filter cake on the filter belt 3, the speed can be adjusted manually or automatically on a gear motor of the drive roller 16. The filter belt 3 is in turn preferably guided around a tension roller 17 and deflection rollers 7, for example two deflection rollers 7. On a deflection roller, preferably on a lower deflection roller 7, which is arranged below the liquid level 20 of the wastewater 1, as in Fig. 2, a scraper can be provided (not shown here) so that the fibers that deposit there are scraped off and nothing can build up.

[0041] The filter belt 3 or the filter belt module is inclined, preferably at an angle of 45°. A replaceable sieve filter plate 14 can be arranged in the upper region of the filter belt 3, preferably in the area of ​​the spray module. The sieve filter plate 14 prevents components of the filter cake from being flushed through the filter belt 3 by the water spray 4.

[0042] In the second part of the filter belt 3, the return area, which is preferably formed vertically, as in Fig.2, the cleaning module is arranged. A brush unit 5, which preferably has at least one brush 5, wherein the brush unit 5 and / or the brush 5 can also be designed so that their position can be changed, separates the filter cake from the filter belt 3. The filter cake preferably falls into a filter press. The filter press is preferably a screw filter press, which has, for example, a screw box 22 and a conveyor screw 19. The filter cake therefore falls, for example, into a screw box 22 arranged below the brush 5 and is transported, transversely to the direction of movement of the filter belt 3, via a conveyor screw 19 for discharge, for example into an on-site container. The filter press advantageously dewaters the filter cake, wherein the resulting water can be fed to the channel 2.

[0043] For maintenance and repair purposes, the wastewater treatment plant has an inspection hatch 15. Reference symbol 1 Wastewater 2 channel 3 filter band 4 water spray 5 Brush unit / brush 6 Control and / or regulation unit 7 pulley 8 Water mist spray unit 9 Water spray nozzle 10 Pump system 11 Pump 12 swivel bearings 13 Swivel drive 14 Sieve filter plate 15 Inspection flap 16 drive roller 17 Tension pulley 18 Hot air connection 19 Conveyor screw 20 Fluid level 21 Enclosure 22 snail box

Claims

[1] Process for the treatment of waste water comprising the following process steps: a. Filtration of substances from wastewater (1) in a channel (2) by means of a filter belt (3) and the concomitant formation of a filter cake on the filter belt (3), b. cleaning the filter cake by means of a water spray (4) in such a way that small organic components are rinsed out of the filter cake and returned to the wastewater (1) in the sewer (2) after the filtration from process step a), c. Cleaning the filter belt (3) and removing the filter cake by means of brushes (5) and / or dewatering the filter cake by means of a filter press. [2] Method according to claim 1, characterized by that the filter belt (3) is a circulating endless filter belt and / or the filter press is a screw filter press. [3] Method according to one of the preceding claims, characterized bythat the following variables are regulated and / or controlled by means of a control and / or regulating unit (6): Filter belt speed, brush speed, screw press speed, water quantity and / or pressure and / or inclination angle of the filter belt. [4] Method according to one of the preceding claims, characterized by that measured values ​​are recorded for control and / or regulation, preferably water level in the channel (2), dimensions of the resulting filter cake, speed of the filter belt, speed of the screw press, flow rate, degree of dryness of the filter cake. [5] Wastewater treatment plant for the treatment of wastewater (1) in an open channel (2) in sewage treatment plants, comprising the following modules: at least one filter belt module which can be set up obliquely in an open channel (2), comprising a filter belt (3) for filtering out substances from the wastewater (1) in the open channel (2), wherein the filter belt (3) is guided circumferentially over deflection rollers (7) and wherein a filter cake is formed on the filter belt (3) when the wastewater treatment plant is used, at least one spray module, which is arranged above a first part of the filter belt (3), for flushing out organic components from the filter cake, at least one cleaning module for cleaning the filter belt module and / or the filter belt (3), wherein the at least one cleaning module is arranged on a second part of the filter belt (3), wherein the at least one cleaning module has a brush unit (5) and / or a filter press in order to clean the filter belt (3) of the filter cake, at least one control and / or regulation unit (6) which is designed to control and / or regulate the modules of the wastewater treatment plant by means of a sensor and / or input unit. [6] Wastewater treatment plant according to claim 5, characterized by that the filter press is a screw filter press. [7] Wastewater treatment plant according to one of claims 5-6, characterized by that the at least one spray module has at least one water mist spray unit (8) having at least one water spray nozzle (9). [8] Wastewater treatment plant according to any one of claims 5-7, characterized by that the spray module has a pump system (10). [9] Wastewater treatment plant according to any one of claims 5-8, characterized by that the filter belt (3) is designed in a sandwich construction, is designed in a single layer and / or is individually adaptable. [10] Wastewater treatment plant according to any one of claims 5-9, characterized bythat the inclination angle of the filter belt module is adjustable.

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