Purification of a bromide-contaminated liquid by extended oxidation

Abstract

Device for purifying a bromide-laden liquid by means of extended oxidation (AOP), comprising in the direction of flow: a) A first reactor (R1) in which at least one reaction converter, preferably two reaction converters (type A, type B) is / are arranged, b) an oxidation reactor (R2) in which at least one mechanical cavitation element (5) and at least one supply device for ozone-containing gas are arranged, c) a control segment (K3) in which at least one and preferably two ozone sensors (6) are arranged for measuring the residual amount of ozone, d) a safety reactor (R4) for destroying the remaining amount of ozone using at least one, preferably at least two, acoustic power converters (safety power converter type C), wherein the frequency(ies) of the safety power converter(s) (type C) differs from the frequency(ies) of the reaction power converter(s) (type A, type B), e) a control unit (7) for controlling the different frequencies and intensities of the acoustic power transducers and / or for controlling the amount of ozone supplied and / or for controlling the rotational speed of the cavitation element (5).

Description

[0001] The present invention relates to a device for the purification of a bromide-laden liquid in private and public sewage treatment plants by enhanced oxidation (AOP process) using ozone. relevance

[0002] Access to clean water is a fundamental prerequisite for a healthy, dignified life and has been recognized as an inalienable human right by the United Nations General Assembly since 2010.

[0003] However, it has been proven that the use of pharmaceuticals, household chemicals, food supplements and care products, as well as the use of chemicals in industry and agriculture, is continuously increasing the pollution of waters with so-called trace substances.

[0004] Surface waters in Germany currently fail to meet the environmental objectives according to Section 4 of the European Water Framework Directive in over 80% of cases, and these objectives can only be partially or not at all achieved by existing wastewater treatment plants with the current treatment stages 1-3.

[0005] In addition to high concentrations of mercury and brominated flame retardants, various micropollutants, especially aromatic hydrocarbons, pesticides, plasticizers, pharmaceuticals and PFOS (i.e. perfluorooctanesulfonic acid and its various salts), can reach concentrations above the µg / L range.

[0006] Wastewater treatment plants themselves represent one of the most significant pathways for micropollutant contamination of surface waters.

[0007] Municipal wastewater treatment plants primarily aim to reduce the burden of organic substances as well as nitrogen and phosphorus compounds (nutrients) by applying mechanical and biological treatment steps.

[0008] Since the novel micropollutants cannot be removed, or can only be removed insufficiently, in the existing treatment stages 1-3, a decision was made at EU level in April 2024. the newly revised EU Urban Wastewater Directive (KIRD) was adopted.

[0009] It establishes a standardized framework for the assessment and control of micropollutants. The guideline stipulates that at least six substances from a defined list of twelve substances must be eliminated by an average of 80%, based on the influent load and taking into account all treatment stages.

[0010] To achieve these goals, public wastewater treatment plants will therefore be required in the future to eliminate these micropollutants by expanding a so-called 4th treatment stage.

[0011] The procedures currently available for this are: 1. Membrane technology 2. Adsorption through the use of activated carbon 3. Oxidation by ozonation

[0012] While membrane technologies are limited in terms of process engineering (membrane blockage and high energy demand), adsorption processes using activated carbon have good effectiveness but involve a number of risks in terms of sorbent regeneration, disposal, transport and especially the CO2 footprint.

[0013] Therefore, the oxidative process through ozonation represents a promising approach to the removal of micropollutants and is already being used in large-scale industrial applications.

[0014] The oxidation process using ozonation enables the removal of both chemical and biological contaminants, as well as organic pollutants, from wastewater. It is important to note that the composition and ratio of biological oxygen demand (BOD) and chemical oxygen demand (COD) in wastewater are constantly changing. Depending on the composition of this matrix and the level of organic pollution, the specific ozone demand varies accordingly.

[0015] Further wastewater treatment (4th treatment stage) by means of ozonation essentially consists of the direct addition of locally generated gaseous ozone into special concrete basins using two main technologies: bubble diffusers and Venturi systems. Challenges and risks associated with the use of ozonation in a wastewater treatment plant

[0016] Despite its good removal performance, the ozone doses used under normal conditions do not lead to complete mineralization of micropollutants, but also to the formation of undesirable oxidation byproducts known as transformation products. To minimize the negative effects of these transformation products on aquatic ecosystems and human health, biological post-treatment is usually carried out directly after ozonation. One notable transformation product, however, is bromate (BrO3). - ), which cannot be broken down by this post-treatment and poses a significant problem due to its carcinogenic properties.

[0017] Therefore, bromate formation represents one of the biggest limitations for the widespread use of ozonation in wastewater treatment. Bromate problem:

[0018] While bromide ions, which are considered harmless, are found in many types of water (swimming pool water, natural waters and seawater, wastewater), the risk of bromate formation and thus a high health risk only arises through the use of an oxidative process such as ozonation in the 4th treatment stage.

[0019] For drinking water, the limit values ​​for bromate defined by both the WHO and the European Union are 10 µg / l.

[0020] Although there is no specifically defined limit value for wastewater, German wastewater treatment plant operators generally orient themselves towards the limit value for drinking water.

[0021] The seriousness of the issue is demonstrated by the legislation of the Netherlands, where the limit has now been lowered to 1 µg / L for both drinking water and wastewater.

[0022] The potential for bromate formation is primarily influenced by two key parameters: 1. the bromide concentration in the wastewater treatment plant's influent and 2. the applied ozone dose. Generally speaking, the higher the bromide concentration, the higher the bromate concentration, and conversely, the higher the ozone dose, the higher the bromate concentration.

[0023] Therefore, in tests to validate the extended ozonation process (AOP) and the associated system described below, both parameters were simultaneously increased to simulate a worst-case scenario. Bromide concentrations of up to 1000 µg / L and specific ozone doses of up to 1.3 gO3 / gDOC were used – nevertheless, the generated bromate values ​​remained within the permissible / harmless range.

[0024] Although recommended threshold values ​​for bromide in wastewater range between 150 and 400 µg / L, these can increase drastically, for example, due to the establishment of a single industrial plant (e.g., using bleach, disinfectants, or flame retardants). The same applies to the ozone dose required to ensure 80% elimination. The combination of these two factors can therefore lead to a critical bromate buildup with unpredictable speed.

[0025] Particularly due to the toxicity and persistence of bromate in nature, it is advisable that the risk of bromate formation be an exclusion criterion for the choice of conventional ozonation in the 4th treatment stage of public wastewater treatment plants.

[0026] The formation of bromate through ozonation in the 4th treatment stage cannot be prevented, let alone controlled, by using previously known AOP processes, since they primarily aim at disinfection services in relation to wastewater treatment plants or treat other, chemically completely different processes (sulfide-containing lye).

[0027] The AOP methods known in the prior art are described, for example, in the European patent specifications: EP2125174B1 (= Procedure “A”), EP2624943B1 (=Procedure “B”) and EP2794492B1 (= method “C”) is described.

[0028] EP2125174B1 describes an ultrasound-assisted method and a corresponding device for gas loading and disinfection of germ-contaminated liquids and wastewater from sewage treatment plants.

[0029] In this process, ozone-containing gas is introduced into the liquid in a reaction chamber under the influence of a mechanical cavitation element. The gas is introduced into the liquid by moving the cavitation element. The microorganisms that come into contact with the ozone are killed within a very short time. The reaction is further enhanced by emitting sound waves into the liquid being treated.

[0030] The movements of the cavitation element ensure that the supplied gas mixes with the liquid being treated, resulting in a relatively large average bubble size. As a second step, the acoustic power transducer simultaneously introduces sound waves directly into the liquid, further reducing the average bubble size throughout the entire liquid. To achieve a sonochemical dissolution of the gas in the liquid, where a predominant proportion of the gas is in a molecularly dispersed form, the power transducer must be designed as an ultrasonic transducer, delivering frequencies in the range of 400 to 1500 kHz, preferably between 600 and 1200 kHz.

[0031] EP2624943B1 describes such a cavitation element, which is characterized by having elongated passage openings with rounded inner walls, wherein the inner walls of the passage openings - seen in a section plane extending along the respective passage opening from the top to the bottom of the cavitation element - have curved profiles and have no edges or corners apart from the edges.

[0032] EP2794492B1 discloses a process for treating sulfide-containing lye by means of ozonation for the chemical conversion of the sulfides by introducing the lye into a reaction chamber comprising at least one acoustic power transducer and a cavitation element; treatment of the lye with ultrasound from the at least one acoustic power transducer, introduction of an ozone-containing gas mixture into the reaction chamber and distribution of the ozone-containing gas mixture in the lye using the cavitation element, wherein the sulfide-containing lye is reacted with the ozone-containing gas mixture to form non-sulfide inorganic sulfur compounds.

[0033] The use of ultrasound in combination with a cavitation element within a reactor chamber, as described in the above-mentioned procedures, may be suitable for reducing micropollutants in addition to disinfection, but it does not prevent bromate formation potentials when used with wastewater from sewage treatment plants.

[0034] The object of the invention is to provide a device for carrying out an AOP process which, in addition to removing micropollutants, prevents the formation of harmful concentrations of bromate. In other words, the aim of the invention is to be able to remove micropollutants by ozonation even in wastewater contaminated with bromides.

[0035] This problem is solved by a device for an AOP method according to claim 1.

[0036] The core of the invention is based on the use of differentiated ultrasound in several different sections of the AOP process or in several different reactor areas / reactors of the overall system for carrying out the AOP process, as will be explained in more detail below.

[0037] The device according to the invention for carrying out an AOP process for purifying a bromide-laden liquid by extended oxidation (AOP) comprises the steps a) Introducing the bromide-laden liquid (usually by a pump) into a first reactor comprising at least one, preferably at least two, acoustic types of power transducers in the ultrasonic range; b) Treatment of the bromide-laden liquid with ultrasound from a first acoustic power transducer (reaction power transducer A) to break down agglomerates. and / or treatment of the bromide-laden liquid with ultrasound from a second acoustic power transducer (reaction power transducer B) to generate hydroxyl radicals. c) Introducing the liquid into an oxidation reactor, introducing an ozone-containing gas mixture into the oxidation reactor and distributing the ozone-containing gas mixture in the bromide-laden liquid using a cavitation element; d) Passing the liquid into a control segment and measuring the residual ozone concentration by means of at least one, preferably two, ozone sensors in the control segment in a gaseous and / or dissolved state and transmitting the residual ozone quantities to a control system; e) Transferring the liquid to a safety reactor and treating the ozonated liquid with specific ultrasound using at least one, preferably two, power converters to destroy residual ozone to prevent bromate formation (safety power converter C); f) wherein the frequency(ies) of the safety power converter(s) preferably differs from the frequency(ies) of the reaction power converter(s).

[0038] In one embodiment, steps a) to f) are performed sequentially twice or even more frequently. The second treatment section / reaction chamber is preferably arranged vertically above the first treatment section / reaction chamber.

[0039] Therefore, after step f) following an execution: g) The treated liquid is introduced vertically under pressure into the second reactor sequence, which is located above the first. Height differences can vary between 0.75 and 2.00 m due to the design. h) Introducing the liquid into a reactor comprising at least one ultrasonic acoustic power transducer; i) Treatment of the liquid with ultrasound from at least one acoustic power converter (preferably reaction power converter B) to generate hydroxyl radicals; j) Introducing the liquid into a further oxidation reactor, introducing an ozone-containing gas mixture into the oxidation reactor and distributing the ozone-containing gas mixture in the bromide-laden liquid using a cavitation element; k) Transferring the liquid to another control segment and measuring the ozone concentration in the control segment using ozone sensors in the gaseous and / or dissolved state and forwarding the values ​​to a control unit; l) Introduction of the ozonated liquid into a further safety reactor and treatment with specific ultrasound to destroy residual ozone in order to prevent bromate formation (safety power converter type C) m) Passing a safety catalyst n) Draining the treated fluid

[0040] According to a further embodiment of the invention, the method additionally comprises the following steps: - Introducing the treated liquid into a reaction chamber - Treatment of the liquid with UV

[0041] According to another embodiment, the method additionally comprises the following steps: - Introducing the treated liquid into a reaction chamber - Adding powdered activated carbon (PAH) to the reaction chamber and distributing it under - Use of a cavitation element

[0042] The individual reactors are tubular reactors, preferably made of stainless steel, with diameters of 100-500mm. Overall, the area of ​​the plant / device in which a sequence of the process is carried out can also be described as a reaction space, whereby it must be clearly stated that different processes are carried out at different points along the flow, which do not overlap.

[0043] Thus, the first reactor and the introduction of ultrasound into the liquid are spatially separated from the cavitation element and the introduction of ozone, since otherwise the ultrasound would reduce the ozone at this point, which is not desired there.

[0044] Acoustic power transducers within the meaning of the invention are devices that are suitable for generating and emitting ultrasonic waves.

[0045] In the first ultrasonic reactor, two power transducers are preferably arranged around the circumference of the tube, with each power transducer preferably being individually controllable.

[0046] The acoustic power transducers play a central role in increasing the reaction speed in the removal of pollutants.

[0047] The overall device preferably uses 3 different types of acoustic power transducers, each with different frequencies for 3 different tasks.

[0048] The different types of acoustic power transducers can also be arranged multiple times in the corresponding reactor to achieve good penetration of the liquid.

[0049] In the first reactor, two different types of power converters are preferably used for a) the comminution of solid agglomerates and b) the formation of hydroxyl radicals. However, to avoid efficiency-reducing interference, the acoustic power converters are preferably operated intermittently in two respects.

[0050] The individual power converters are preferably driven sequentially with different frequencies, and – to increase effectiveness – impulses with higher energy density are preferably generated instead of a constant activity level during the “on” phase.

[0051] In the safety reactor, an acoustic power converter type C is used to abruptly interrupt the potential bromate formation process by destroying the existing residual ozone in the previously ozonated liquid (safety power converter).

[0052] In the reactors of the second sequence, if present, reaction power converters and safety power converters are used analogously to the first sequence.

[0053] For the reaction power converters type A and B, frequencies of 600-2400 kHz are preferably used.

[0054] For safety power converters, frequencies of 150-400kHz are preferred.

[0055] Cavitation elements are devices capable of generating cavitation bubbles (vapor-filled cavities) in liquids. These elements are typically fast-moving objects within a liquid, such as impellers of centrifugal pumps, water turbines, screws, or propellers.

[0056] All cavitation elements described in WO 2008 / 080618 A 1 and EP2624943B1 can be used to implement the method according to the invention. Cavitation elements in the form of disc-shaped disks with a rough, special coating are preferred.

[0057] The reaction chamber for the cavitation element is designed in the form of a tubular reactor (oxidation reactor). It also includes a gas supply unit as known from WO 2008 / 080618 A 1 and EP2624943B1, for the introduction of an ozone / oxygen mixture, but no acoustic power transducers, as these would be counterproductive for the ozonation process.

[0058] Preferably, the bromide-laden liquid to be treated is passed through the oxidation reactor by the pressure of a pump.

[0059] At the same time, an ozone / oxygen mixture is introduced into the oxidation reactor via a pressure line.

[0060] The movements of the cavitation element ensure that the supplied gas mixes with the liquid being treated. This initiates a very rapid oxidation process in which the unwanted micropollutants are reduced.

[0061] The rotational speed of the cavitation element is preferably determined by a proprietary algorithm. Additionally, the dose of the introduced ozone gas mixture can be efficiently adjusted in parallel.

[0062] Due to the locally varying water matrix, a specific ozone depletion behavior occurs, leading to a different amount of residual ozone. In the case of a bromide-contaminated liquid, this residual ozone poses a significant risk for potential bromate formation.

[0063] To determine the residual ozone quantity, the treated liquid is passed directly through a sensor segment (K3) after reactor 2. In this segment, the proportion of any residual ozone is measured by means of two ozone sensors, preferably dissolved in the bromide-laden liquid and in the gas phase surrounding the liquid being treated. After determining the residual ozone quantity, the treated liquid is subjected to ultrasound by the safety transducer(s) in the subsequent safety reactor after the oxidation reactor. This ultrasound destroys the residual ozone.

[0064] The process according to the invention takes advantage of the fact that the reaction from bromide to bromate does not proceed in a single step, but via several intermediate stages. The immediate destruction of the residual ozone by the safety power converters thus ensures that a potential bromate formation reaction is interrupted at an early stage.

[0065] The safety power converters are installed in a tubular reactor (safety reactor) downstream of the oxidation reactor and can be controlled in terms of frequency and intensity in such a way that even the smallest residual amounts of ozone are destroyed.

[0066] Another factor in preventing bromate formation is the significant reduction in reaction time for micropollutant reduction compared to conventional ozonation processes. In the process according to the invention, the reaction time is reduced to less than 1 minute, which represents an approximately 20-fold reduction in reaction time compared to classical ozonation.

[0067] To ensure complete elimination of micropollutants even in difficult cases, the wastewater is pumped vertically into a further, identical sequence of reactors above it after leaving the safety reactor (safety converter), and the individual treatment steps are repeated.

[0068] Height differences can vary between 0.75m and 2.00m due to the design.

[0069] First, an ultrasonic treatment with at least two type B reaction power converters is performed to generate hydroxyl radicals. Due to the high oxidation potential, any remaining micropollutants in this reactor can be further reduced.

[0070] The wastewater then passes through a second oxidation reactor, which, like the first oxidation reactor, is equipped with a cavitation element and a gas supply unit.

[0071] In this reactor, an ozone / oxygen mixture is introduced again via a pressure line and mixed by the cavitation element. Both the dose of the introduced ozone gas mixture and the rotational speed of the cavitation element are preferably adjusted by the control system to achieve an optimal oxidation reaction.

[0072] Since residual ozone can be generated again through this preferably second ozonation, the treated liquid is preferably passed through a further sensor segment after the oxidation reactor, in which the proportion of possible residual ozone is measured by means of two ozone sensors, in particular preferably dissolved in the bromide-laden liquid and in the gas phase surrounding the liquid to be treated.

[0073] After determining the residual ozone quantity, the treated liquid is subjected to ultrasound by the safety converters in the subsequent safety reactor, which destroys the residual ozone. Thus, the immediate destruction of the residual ozone by the safety converters ensures that any potential bromate formation reaction is interrupted at an early stage.

[0074] In a preferred embodiment of the invention, the wastewater is guided through a pipe unit after leaving the last safety reactor, which is equipped with a gas vent with catalyst for safety reasons.

[0075] After leaving the plant, the wastewater is usually sent for biological post-treatment. Option 1

[0076] In a particular embodiment, the wastewater is directed into a further tubular reactor after leaving the catalyst unit, which is equipped with UV treatment units. Option 2

[0077] In a particularly specific embodiment, the wastewater, after leaving the catalyst unit, is directed into a further tubular reactor equipped with a cavitation element analogous to the oxidation reactor and a dosing option for powdered activated carbon (PAC). The rotation of the cavitation element mixes the ground PAC and additionally breaks down PAC agglomerates of small PAC particles. This makes it possible to further reduce the specific total ozone dose. steering

[0078] In addition to the process-relevant ozone sensors for controlling the safety converters, sensors can be installed in the reactors / reaction chambers and / or supply lines to record values ​​such as temperature, pressure, redox potential, pH, oxygen quantity, ozone dose, flow rate, frequency and / or intensity of the ultrasound, and rotational speed of the cavitation element. By recording these values, the reactions in the individual reactors, as well as the overall process, can be influenced from a central control unit.

[0079] As already explained, to avoid bromate formation, it is particularly important to shorten the duration of exposure of the bromide-laden liquid to the ozone-containing gas mixture while simultaneously ensuring sufficient elimination performance for the reduction of micropollutants.

[0080] In a particular embodiment, an additional device is provided for measuring the initial bromide concentration when the bromide-laden liquid is introduced into the reaction chamber. The measured values ​​can be transmitted to the control unit, which can then process them and use them to adjust the reaction parameters.

[0081] In a preferred embodiment, an analytical system for monitoring the bromide load of the wastewater is located in the inlet area of ​​the first tubular reactor. The data collected here are also incorporated into the process control, enabling not only efficiency adjustments to the AOP process but also continuous and efficient hazard monitoring and management.

[0082] The arrangement of additional reaction chambers is modular. Modifications can be made modularly and do not require the construction of a completely new plant. Using multiple reaction chambers does not increase the reaction time. Example 1

[0083] In this example, the reaction chamber (consisting of several reactors and a control segment) is arranged in a tube and includes an ultrasonic segment for the disruption of solid agglomerates and increased generation of hydroxyl radicals. The use of ultrasound creates cavitation bubbles. Within the cavitation bubble, water is homolytically split into H and OH radicals (Bober, U., 1998; Fang et al., 1996).

[0084] Furthermore, the reactor includes a gas injection system corresponding to the mechanical cavitation element patented in EP2624943B1. This reduces ozone consumption and reaction times. The subsequent reactor also includes an additional ultrasonic segment / safety power converter after the gas injection through the feed device.

[0085] The process according to the invention takes place fully controlled within a closed space (pipeline). No further reaction or retention basins are required. Example 2

[0086] In one example, it was shown that by using the cavitation element according to the invention, a more efficient ozone input could be achieved than with conventional input systems via diffusers or pump-injector systems, resulting in reduced reaction times and a lower requirement for ozone for comparable elimination performance.

[0087] In contrast to conventional ozonation, the entire process does not take place in reaction tanks, but in a closed, very compact tubular reactor.

[0088] This example concerns a system comprising two redundant, series-connected tubular reactors (300 mm pipe diameter), each with ultrasonic resonators (reaction power converters), a cavitation element (OptimiXer®), and downstream ultrasonic resonators (safety power converters). The reactors include a degassing unit to remove residual oxygen generated during the process, via a catalyst to destroy any residual ozone, and a Primozone ozone generator (Löddeköpinge, Sweden).

[0089] Outside the reactors are the control system, pump, cooling system, and a VSA oxygen generator. The entire system can be controlled remotely. Remote diagnostics and recording of process data and setting parameters of the individual system components are possible. As an alternative to the on-site VSA oxygen generator, the oxygen requirement for ozone production is met by cylinder bundles filled to 300 bar. Furthermore, cooling for the ozone generator and a centrifugal pump for flow rates up to 50 m³ / h are available.

[0090] The gas input is achieved exclusively through the normal operating pressure of the ozone generator.

[0091] As a precaution, the system includes protective devices for the escape of ozone or oxygen from redundant catalysts and sensors for emergency shutdown and ventilation.

[0092] A sand filter is also available.

[0093] The proprietary holistic control system of the systems includes the elements measuring probes, pump, ultrasonic control and frequency, ozone generation, ozone input (rotation speed of the OptimiXers®) as well as safety elements such as gas sensors.

[0094] The main control parameters in the system are ozone dose and volume flow. The adjustment of the individual control elements of the system is fully automatic.

[0095] The formation of unwanted bromate from bromide was investigated in the facility.

[0096] Bromide concentrations in the effluent were measured at 58 - 170 µg / L (n = 19) over the entire experimental period. Example 3: The system has a flow capacity of 1 - 4 m3 / h with a pipe diameter of 100 mm.

[0097] The wastewater to be treated is filled into a 1000 L IBC container with a test volume of 535 L, which is treated in a closed-loop system with consecutively increasing dosages.

[0098] To investigate the bromate formation potential, bromide is added to the wastewater to be treated at concentrations of 250, 500 and 1,000 µg / L.

[0099] Since the potential formation of bromate is also strongly dependent on the specific ozone dose, this was also significantly increased during the experiments. While specific ozone doses of < 0.3 mgO3 / mgDOC are generally sufficient for the normal operation of an AOP (Automated Occupational Therapy) plant, the specific ozone doses were increased to up to 1.3 mgO3 / mgDOC in this experiment. The results are presented in Fig. Figure 4 is shown. For clarity, the y-axis is displayed logarithmically. Analysis values ​​below the detection limit are shown as unfilled dots.

[0100] The invention will be explained in more detail below with reference to drawings.

[0101] This shows: Fig. 1 a schematic diagram of the device according to the invention with the reactors and the control segment in a tubular reactor; Fig. 2 a schematic diagram of the device according to the invention with the reactors and the control segments for two treatment sequences in the tubular reactor; Fig. 3 a schematic diagram of the device according to the invention with a reaction chamber in the batch process; Fig. 4 a diagram of bromate formation in an experimental setup; Fig. 5 a more detailed schematic diagram of the device according to the invention with a sequence of tubular reactors for flow-through inline operation; Fig. 6 a more detailed schematic diagram of the device according to the invention with a sequence of tubular reactors for flow-through inline operation with UV application; Fig. 7 a more detailed schematic diagram of the device according to the invention with a sequence of tubular reactors for flow-through inline operation with PAH use.

[0102] Fig. Figure 1 shows a schematic diagram of the device according to the invention for a treatment sequence. All components – the reactors and the control segment for the treatment sequence – are arranged in a tube.

[0103] The area of ​​a system in which a treatment sequence is carried out can also be called a reaction space, although this still has different areas in which different processes take place.

[0104] The reaction chamber comprises a cavitation element 5 and two ultrasonic elements in the form of ultrasonic probes 4a and 4b, wherein one ultrasonic probe 4a is located upstream of the cavitation element 5 and the other ultrasonic probe 4b is located downstream of the cavitation element 5. The reaction chamber also includes at least one ozone sensor 6 and a feed device (not shown) for the ozone gas mixture.

[0105] The ozone gas mixture is introduced into the cavitation element 5 via a feed device. At least one ozone sensor 6 is arranged between the cavitation element 5 and the downstream ultrasonic probe 4, by which the residual amount of ozone present in the reaction chamber 1 is determined.

[0106] A control unit 7 is arranged outside the reaction chamber 1 and connected to the ultrasonic probes 4a and 4b, the cavitation element 5, and the at least one ozone sensor 6. The control unit 7 is also connected to a bromide analysis device 8, which is located upstream of the reaction chamber 1. Based on the measured values ​​obtained, the control unit 7 can influence the various devices connected to it in order to control the reactions, in particular the formation of bromates. Preferably, this is done by adjusting the ozone dose in the reaction chamber by setting or correcting one or more parameters. Optionally, a catalyst 3 for the elimination of gaseous ozone is connected downstream of the reaction chamber.

[0107] Fig. Figure 2 shows the device according to the invention with two reaction chambers 1 in the tubular reactor 2.

[0108] The structure of reaction chamber 1 is identical to the structure of reaction chamber 1. Fig. 1. The structure is modular and both reaction chambers are arranged sequentially in the tubular reactor 2.

[0109] A device for bromide analysis 8 is connected upstream of the first reaction chamber 1 and the catalyst 3 is connected downstream of the second reaction chamber 1.

[0110] Fig. Figure 3 shows the device according to the invention with a reaction chamber 1 in a batch process. The reaction chamber 1, like the reaction chambers 1, is made of Fig. 1 and Fig. 2. A closed loop of the tubular reactor 2 allows the bromide-laden liquid to be fed into the reaction chamber as often as desired. This is controlled by the control unit 7. Once sufficient purification has been achieved, the bromide-laden liquid is removed from the loop. This setup enables the treatment of wastewater in a buffer tank 9 in a closed loop. For this purpose, the contents of the buffer tank 9 are treated in one or more steps. This so-called batch process also allows for decentralized treatment at point sources such as hospitals.

[0111] Fig. Figure 4 shows that no relevant bromate formation occurs in the process according to the invention, neither with high specific ozone doses nor with high initial bromide concentrations. During the investigations, bromate formation could only be detected in isolated cases (2 out of 22 samples), and these were within the range of the drinking water limit. A systematic correlation between bromide concentration and ozone dose could not be established. Neither with an exceptionally high initial bromide concentration (10-fold) nor with a theoretically high ozone dose (5-fold) was bromate formation detectable.

[0112] Fig. Figure 5 shows a preferred embodiment of the device according to the invention in a schematic diagram with the individual reactors.

[0113] The wastewater to be treated is introduced into reactor R1 via pump 11.

[0114] In reactor R1, the water is treated by at least two different ultrasonic units (reaction power converters) to break down solid agglomerates (reaction power converter type A) and to generate hydroxyl radicals (reaction power converter type B). In the next step, the water is pumped through an oxidation reactor R2, in which an ozone gas mixture is distributed and dissolved via a pressure line using a rotating cavitation element. The resulting residual ozone is detected by sensors in the subsequent pipe segment, control segment K3, and then destroyed in the safety reactor, R4, by at least two acoustic power converters (safety power converter type C). The liquid is then pumped vertically into a further reactor sequence located above it. In this sequence, at least two acoustic power converters (reaction power converter type B) in reactor R5 generate hydroxyl radicals, which are then broken down.

[0115] The liquid is intended to oxidize micropollutants. It then enters a second oxidation reactor, R6, where an ozone gas mixture is introduced and distributed via a cavitation element. In the subsequent control segment, K7, the remaining ozone is measured and then destroyed in the safety reactor, R8, using at least two acoustic power converters (safety power converters).

[0116] After leaving the R8, the wastewater passes through another pipe unit equipped with a gas vent and K9 catalyst. Upon exiting the system, the wastewater is then sent for biological post-treatment.

[0117] In a central control unit 0, the values ​​from different sensors from the individual reactors are combined and processed.

[0118] The main functions include the dynamic adjustment of the ozone dosage, the control of the 3 ultrasound types and, in particular, the residual ozone destruction to shorten the reaction time and to prevent bromate formation.

[0119] Fig. Figure 6 shows a schematic diagram of a preferred embodiment of the device according to the invention with individual reactors for flow-through inline operation with UV application.

[0120] The wastewater to be treated is introduced into reactor R1 by means of a pump (1).

[0121] In reactor R1, the water is treated by at least two different ultrasonic units (reaction power converters) to break down solid agglomerates (reaction power converter type A) and to generate hydroxyl radicals (reaction power converter type B). In the next step, the water is pumped through an oxidation reactor, reactor R2, in which an ozone gas mixture is distributed and dissolved via a pressure line using a rotating cavitation element. The resulting residual ozone is detected by sensors in the subsequent pipe segment, control segment K3, and then destroyed in the safety reactor, reactor R4, by at least two acoustic power converters (safety power converters). The liquid is then pumped vertically into a further reactor sequence located above it.In reactor R5, at least two acoustic power converters (type B reaction power converters) generate hydroxyl radicals to oxidize any micropollutants present. The liquid then enters a second oxidation reactor, reactor R6, where an ozone gas mixture is introduced and distributed via a cavitation element. In the subsequent control segment K7, the remaining ozone is measured and then destroyed in reactor R8 using at least two acoustic power converters (safety power converters).

[0122] After leaving reactor R8, the wastewater passes through another pipe section equipped with a gas vent and catalyst K9. The wastewater is then treated with UV radiation in reactor R10. After leaving the plant, the wastewater is sent for biological post-treatment.

[0123] In a central control unit 0, the values ​​from various sensors in the individual reactors are combined and processed. Its main functions include the dynamic adjustment of the ozone dosage, the control of the three ultrasound types, and, in particular, the destruction of residual ozone to shorten the reaction time and prevent bromate formation.

[0124] Fig. Figure 7 shows the schematic diagram of a further embodiment of the device according to the invention with PAK insert.

[0125] The wastewater to be treated is introduced into reactor R1 by means of a pump (1).

[0126] In reactor R1, the water is treated by at least two different ultrasonic units (reaction power converters) to break down solid agglomerates (reaction power converter type A) and to generate hydroxyl radicals (reaction power converter type B). In the next step, the water is pumped through an oxidation reactor, reactor R2, in which an ozone gas mixture is distributed and dissolved via a pressure line using a rotating cavitation element. The resulting residual ozone is detected by sensors in the subsequent pipe segment, control segment K3, and then destroyed in the safety reactor, reactor R4, by at least two acoustic power converters (safety power converters). The liquid is then pumped vertically into a further reactor sequence located above it.In reactor R5, at least two acoustic power converters (type B reaction power converters) generate hydroxyl radicals to oxidize any micropollutants present. The liquid then enters a second oxidation reactor, reactor R6, where an ozone gas mixture is introduced and distributed via a cavitation element. In the subsequent control segment K7, the remaining ozone is measured and then destroyed in reactor R8 using at least two acoustic power converters (safety power converters).

[0127] After exiting reactor 8, the wastewater is routed through another pipe section equipped with a gas vent and catalyst K9. Following this, the wastewater enters another pipe reactor, reactor R10, which is equipped with a cavitation element similar to those in reactors K3 and R6, as well as a dosing system for powdered activated carbon (PAC). The rotation of the cavitation element mixes the ground PAC and also breaks down PAC agglomerates of small PAC particles. This allows for a further reduction in the specific total ozone dose.

[0128] After leaving the plant, the wastewater is sent for biological post-treatment.

[0129] In a central control unit 0, the values ​​from various sensors in the individual reactors are combined and processed. Its main functions include the dynamic adjustment of the ozone dosage, the control of the three ultrasound types, and, in particular, the destruction of residual ozone to shorten the reaction time and prevent bromate formation. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2125174B1 [0027, 0028] EP 2624943B1 [0027, 0031, 0056, 0057, 0084] EP 2794492B1 [0027, 0032] WO 2008 / 080618 A [0056, 0057] Cited non-patent literature

[0000] Bober, U., 1998; Fang et al., 1996

[0083]

Claims

[1] Device for purifying a bromide-laden liquid by means of extended oxidation (AOP), comprising in the direction of flow: a) A first reactor (R1) in which at least one reaction converter, preferably two reaction converters (type A, type B) is / are arranged, b) an oxidation reactor (R2) in which at least one mechanical cavitation element (5) and at least one supply device for ozone-containing gas are arranged, c) a control segment (K3) in which at least one and preferably two ozone sensors (6) are arranged for measuring the residual amount of ozone, d) a safety reactor (R4) for destroying the remaining amount of ozone using at least one, preferably at least two, acoustic power converters (safety power converter type C), wherein the frequency(ies) of the safety power converter(s) (type C) differs from the frequency(ies) of the reaction power converter(s) (type A, type B), e) a control unit (7) for controlling the different frequencies and intensities of the acoustic power transducers and / or for controlling the amount of ozone supplied and / or for controlling the rotational speed of the cavitation element (5). [2] Device according to claim 1, wherein a reactor (R1, R2, R4) or control segment (K3) comprises at least one temperature sensor. [3] Device according to claim 1-2, wherein a reactor (R1, R2, R4) or control segment (K3) comprises a pressure sensor. [4] Device according to one of claims 1-3, wherein the reactors (R1, R2, R4) and control segments (K3) are arranged in a tubular reactor. [5] Device according to one of claims 1-4, wherein the reactors (R1, R2, R4) and the control segment (K3) according to a) to d) are arranged at least twice in succession in the same sequence for at least one further treatment sequence. [6] Device according to one of the preceding claims, characterized by that the reaction power converter(s) in the first reactor (R1) do not affect the oxidation reactor (R2), as this would result in an unwanted degradation of ozone by ultrasound in this process step. [7] Device according to any of the preceding claims, wherein the frequency of the safety power converter(s) (Type C) or the average frequency at several frequencies is lower than the frequency of the power converter(s) (Reaction power converter Type A, Type B). [8] Device according to one of the preceding claims, wherein the introduction of the ozone-containing gas mixture is controlled by the control unit (7). [9] Device according to any of the preceding claims, characterized by that the time for an entire treatment sequence is preferably less than 2 minutes and further preferably less than 1.5 minutes. [10] Device according to any of the preceding claims, characterized by that the reactors / reaction chambers and the control segment (K3) are arranged in a tubular reactor. [11] Device according to any of the preceding claims, characterized by, that reactors (R5, R6, R8) for a second treatment sequence are downstream, wherein the reactors (R5, R8) necessary for the second sequence and the control segment (K7) are arranged in the direction of flow behind the reactors (R1, R2; R4) and the control segment (K3) of the first sequence and vertically above them.

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