Purification of a bromide-laden liquid by extended oxidation (AOP)

Abstract

Device for purifying a bromide-laden liquid by means of extended oxidation (AOP), comprising a reaction chamber (1), at least one mechanical cavitation element (5) and at least one supply device for ozone-containing gas; characterized in that the device further comprises at least one first acoustic power converter (reaction power converter) (4a) for supporting the oxidation reaction and at least one second acoustic power converter (safety power converter) (4b) for destroying any residual amount of ozone that may be present, as well as one or more ozone sensors (6) and at least one control unit (7) connected to the ozone sensor(s), the supply device and at least one acoustic power converter for controlling the amount of ozone-containing gas supplied to and / or present in the reaction chamber (1).

Description

[0001] The present invention relates to a method and a device for purifying a bromide-contaminated liquid by extended oxidation (AOP).

[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 water bodies with so-called trace substances.

[0004] Not only do over 80% of surface waters in Germany fail to meet the environmental targets set out in Section 4 of the European Water Framework Directive, which existing wastewater treatment plants with current treatment stages 1-3 can only partially achieve, or even not at all, but wastewater treatment plants themselves represent one of the most significant pathways for trace substance pollution in surface waters.

[0005] This must be counteracted, which is why the EU Urban Waste Water Directive, adopted in 2023, obliges member states to expand municipal wastewater treatment plants to include the so-called fourth treatment stage by 2035 at the latest, in particular to eliminate undesirable trace substances.

[0006] In recent years, two methods have proven to be effective and practical in numerous trials: 1. The adsorption process using activated carbon 2. The oxidation process by ozonation.

[0007] While the adsorption process using activated carbon still leaves several unresolved questions regarding sustainability and economic efficiency, the oxidation process using ozonation has so far achieved good results, both in terms of sustainability and economic efficiency.

[0008] It has also been shown that the oxidation process through ozonation can remove chemical, biological and organic pollutants.

[0009] EP2125174B1 describes an ultrasound-assisted process and a corresponding device for gas loading and disinfection of liquids and wastewater from sewage treatment plants contaminated by germs.

[0010] 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 the movement of the cavitation element. Microorganisms that come into contact with the ozone are killed in a very short time. The reaction is supported by the emission of sound waves into the liquid being treated.

[0011] The movements of the cavitation element ensure that the supplied gas mixes with the liquid to be treated, where the average bubble size is still relatively large. As a second measure, the acoustic power converter simultaneously introduces sound waves directly into the liquid, further reducing the average bubble size throughout the liquid. To achieve a sonochemical solution of the gas in the liquid, in which the majority of the gas is present in a molecularly dispersed form, the power converter must be designed as an ultrasonic transducer that delivers frequencies in a range between 400 and 1500 kHz, preferably between 600 and 1200 kHz.

[0012] EP2624943B1 describes such a cavitation element, which is characterized in that it has elongated through-openings with rounded inner walls, wherein the inner walls of the through-openings - seen in a sectional plane extending along the respective through-opening from the top to the bottom of the cavitation element - have curved profiles and have no edges or corners apart from the edges.

[0013] EP2794492B1 discloses a method for treating a sulfide-containing waste liquor by ozonation for chemically converting the sulfides by introducing the waste liquor into a reaction chamber comprising at least one acoustic power transducer and a cavitation element; treating the waste liquor with ultrasound from the at least one acoustic power transducer, supplying an ozone-containing gas mixture into the reaction chamber, and distributing the ozone-containing gas mixture in the waste liquor using the cavitation element, wherein the sulfide-containing waste liquor is reacted with the ozone-containing gas mixture to form non-sulfidic inorganic sulfur compounds.

[0014] The disadvantage of such oxidation processes is the risk associated with the formation of transformation products such as nitrosamines and bromate.

[0015] Wastewater and natural waters are often contaminated with bromide, as are swimming pools filled with mixed water or brine.

[0016] Sources of bromide identified so far include geogenic sources and waste disposal facilities. Local industrial companies (e.g., those using bleaching agents or flame retardants) can also discharge bromide into municipal wastewater.

[0017] Since nitrosamines can be removed by biological post-treatment, but bromate cannot, the potential for bromate formation represents a significant risk for the choice of ozonation process and, of course, an environmental risk.

[0018] Conventional ozonation of bromide-containing water can lead to the formation of bromate. The bromate formation potential does not fully permit the use of ozonation as a process option for advanced wastewater treatment to eliminate trace substances. The Swiss Ecotox Centre has derived a chronic quality criterion for bromate for surface waters (environmental quality standard) of 50 µg / L, in accordance with the Drinking Water Ordinance. At bromide concentrations of up to 150 µg / L and a maximum specific ozone dose of 0.7 mg O3 / mg DOC, no restrictions on the applicability of ozonation for the treatment of municipal wastewater are expected (DWA, 2022). At higher concentrations (> 150 µg / L) or when drinking water is obtained downstream of the wastewater treatment plant discharge, a case-by-case assessment of the bromate formation potential of the wastewater should be carried out (Brückner et al., 2018; DWA, 2022; Jahan et al., 2021; KOM-M.NRW, 2016).

[0019] A changed discharge situation into the inflow of the wastewater treatment plants, e.g. due to further industrial settlements, could lead to higher bromide values ​​in the effluent of the wastewater treatment plants in the future and thus limit the suitability of conventional ozonation as a method for trace substance elimination.

[0020] The use of an advanced ozonation process (Advanced Oxidation Processes (AOP)) is intended to reduce or eliminate the risk of bromate formation in wastewater contaminated with bromide. During treatment or disinfection with ozone, care must be taken to ensure that no harmful concentrations of bromate are formed.

[0021] The object of the invention is to provide a method and a device for carrying out an ozonation process which, in addition to removing pollutants, prevents the formation of harmful concentrations of bromate. Such pollutants can be biological pollutants, such as germs, chemical pollutants or, in particular, trace substances.

[0022] Trace substances are unwanted synthetic substances found in water, occurring in concentrations ranging from nanograms to a few micrograms per liter. Organic trace substances are part of everyday life and are used in many areas, such as household chemicals and pharmaceuticals.

[0023] The object is achieved by a method and a device according to claim 1.

[0024] The process according to the invention is a process for the purification of a bromide-contaminated liquid by extended oxidation (AOP) comprising the steps a) introducing the bromide-laden liquid into a reaction chamber comprising at least two acoustic power transducers, at least one cavitation element and at least one ozone sensor; b) treating the bromide-contaminated liquid with ultrasound from at least one first acoustic power converter (reaction power converter), c) feeding an ozone-containing gas mixture into the reaction chamber and distributing the ozone-containing gas mixture in the bromide-laden liquid using the cavitation element; d) measuring the ozone concentration by means of the at least one ozone sensor following step c), e) Determination of the residual amount of ozone in the reaction chamber following step c).

[0025] Acoustic power transducers within the meaning of the invention are devices that are capable of generating and emitting ultrasonic waves.

[0026] Preferably, several acoustic power transducers are arranged upstream of the cavitation element. These are particularly preferably arranged in a ring and evenly distributed around the pipe circumference, with each power transducer preferably being individually controllable. Further preferably, several acoustic power transducers are arranged upstream of the cavitation element along the pipe. For example, 12 individually controllable power transducers can always be arranged in a ring around the pipe circumference, with four power transducers being distributed at three locations along the pipe. This has been shown to achieve particularly good water treatment.

[0027] Cavitation elements are elements capable of generating so-called cavitation bubbles (vapor-filled cavities) in liquids. Such elements are typically fast-moving objects in a liquid, such as impellers of centrifugal pumps, water turbines, screws, or propellers.

[0028] The basic structure of the reaction chamber with the mechanical cavitation element and a device for supplying ozone-containing gas is basically known from WO 2008 / 080618 A1, to which reference is hereby made.

[0029] To implement the method according to the invention, all cavitation elements can be used, preferably cavitation elements as described in EP2624943B1 are used.

[0030] According to the process according to the invention, the bromide-contaminated liquid to be treated is passed through at least one reaction chamber. This bromide-contaminated liquid can be wastewater, water from a natural body of water, or from a swimming pool. The process is preferably used for the treatment of wastewater, particularly in sewage treatment plants. When using wastewater, it is preferably pumped into an elevated basin and flows automatically through the device according to the invention due to the difference in height.

[0031] The use of pumps to realize the flow movement of the bromide-contaminated liquid to be treated through the device according to the invention is also possible.

[0032] According to the invention, the device is designed such that the bromide-laden liquid to be treated passes through at least one acoustic power transducer (reaction power transducer) before it encounters the cavitation element. The power transducer is designed, in particular, as an ultrasonic transducer. By means of the reaction power transducer, sound waves are introduced into the bromide-laden liquid to be treated (hereinafter referred to as the liquid to be treated), thereby promoting the reaction. Furthermore, the ultrasound preferably crushes the gas bubbles introduced into the liquid to be treated by the cavitation element, which can lead to a molecularly dispersed solution of the gas mixture, which is introduced into the liquid to be treated during and / or after the ultrasonic treatment.

[0033] The reaction is carried out at frequencies in a range between 250 and 2300 kHz, in particular greater than 1200 kHz to 2300 kHz, particularly preferably from 400 to 2100 kHz and is adjusted depending on the bromide load.

[0034] According to one embodiment, several piezo elements are used as multiple power converters, which are arranged in front of the cavitation element and can be individually controlled. Particularly preferred are the power converters switched on and off intermittently. This allows for a higher power input.

[0035] The movements of the cavitation element ensure that the supplied gas mixes with the liquid to be treated. The gas is preferably an ozone-containing gas mixture, particularly preferably an oxygen / ozone mixture.

[0036] By introducing the gas into the liquid to be treated, a rapid and effective removal of undesirable substances is achieved using the cavitation element. Ultrasonic treatment supports this reaction and reduces the reaction time.

[0037] In a preferred embodiment of the invention, the process is carried out under atmospheric pressure conditions.

[0038] According to a particularly preferred embodiment of the method according to the invention, temperature sensors and / or pressure sensors are provided in the reaction chamber and / or in the supply or discharge lines, with the measured temperature values ​​and / or pressures being evaluated in a control device. In a further preferred embodiment, the pH value of the bromide-contaminated liquid is determined using at least one device and evaluated in a control device. This evaluation can be used, if necessary, to calculate the amount of ozone to be supplied to the reaction chamber.

[0039] The process is preferably carried out in such a way that the entire amount of ozone supplied to the reaction chamber is consumed. According to the invention, the ozone concentration can be measured using at least one ozone sensor, preferably after or during the reaction. The proportion of possible residual ozone is preferably measured using two ozone sensors, particularly preferably dissolved in the bromide-contaminated liquid and in the gas phase surrounding the liquid to be treated. Based on these values, the residual amount of ozone in the reaction chamber is determined.

[0040] These measured values ​​represent an important element for the control algorithm.

[0041] A preferred method is one in which, in step d), the dissolved amount of ozone in the bromide-contaminated liquid is measured using an ozone sensor, and the amount of ozone in the gas phase surrounding the bromide-contaminated liquid is measured using another ozone sensor, and the residual amount of ozone in the reaction chamber is determined using a program. The ozone concentration in the gas phase is particularly rapid and can thus accelerate control. The ozone concentration in the liquid is important for detecting that the reaction is complete.

[0042] Preferably, if a residual amount of ozone is present, a further treatment with ultrasound from at least one additional acoustic power converter (safety power converter) is carried out as step f) to destroy the residual amount of ozone in the bromide-contaminated liquid. Preferably, a plurality of acoustic power converters are arranged in a circle around the circumference of the pipe. Here, too, several power converters can be arranged along the pipe.

[0043] In an alternative variant, a continuous treatment with ultrasound from at least one further acoustic power converter (safety power converter) can also be carried out in order to remove the residual ozone from the bromide-contaminated liquid.

[0044] Preferably, the frequency and intensity of the ultrasound in the further ultrasound treatment in step f) or in a continuous ultrasound treatment by the safety transducer are controlled by a control unit.

[0045] The safety power converter(s) preferably operate at frequencies between 250 and 1200 kHz, with frequencies between 400 and 1000 kHz being particularly preferred, and frequencies between 250 and 600 kHz being most preferred. Overall, it has been shown that the safety power converter should preferably be operated at a lower frequency or within a smaller and lower frequency spectrum than the power converter(s) installed upstream of the cavitation element.

[0046] Preferably, the ultrasonic treatment by means of the safety power converter takes place during and / or after the introduction of the ozone-containing gas mixture into the bromide-contaminated liquid.

[0047] In addition, the dose of the introduced ozone gas mixture can be efficiently adjusted in parallel.

[0048] The process according to the invention takes advantage of the fact that the reaction of bromide with ozone does not occur directly in a single step, but proceeds through several intermediate stages in which various intermediate products are formed and react further. This leads to a reduced overall reaction rate.

[0049] Thus, in the case of the presence of residual ozone, at least one subsequent acoustic power converter (safety converter) can be controlled in terms of frequency and intensity in such a way that even the smallest residual amounts of ozone can be destroyed and the bromate formation potential is reduced by shortening the contact time.

[0050] Compared to conventional ozonization processes, the reaction time in the process according to the invention can be reduced to a maximum of 3 minutes, preferably a maximum of 2 minutes and particularly preferably a maximum of 1 minute, which results in only a small amount or no bromate being formed in the bromide-contaminated liquid.

[0051] In a preferred embodiment of the method, a second gas introduction unit is provided.

[0052] This allows, with the help of the described control elements, the required ozone dose to be distributed between two injection points if necessary. This not only enables the introduction of high doses of ozone, but also reduces the respective contact time and thus the potential for bromate formation, even at high bromide and high ozone doses.

[0053] In this preferred embodiment, after the second ozone injection, any residual ozone is also measured using two probes. The measured values ​​are directly incorporated into the overall control system described above.

[0054] Preferably, the reaction chamber is arranged in a tubular reactor. Another embodiment of the invention enables the treatment of bromine-contaminated liquids, such as wastewater, in a buffer tank in a closed circuit.

[0055] Particularly preferred is a process which is characterized in that it is carried out at least twice with the bromide-laden liquid in at least two reaction chambers arranged one behind the other within a tubular reactor, or particularly preferred is a correspondingly designed plant.

[0056] Following a second gas introduction unit, if present, which is designed to introduce the gas mixture into the second reaction chamber, ultrasonic units / safety power converters are also provided, which, as in the first reaction chamber, can be controlled using the measured values ​​determined - or, according to another embodiment, run continuously.

[0057] In a particularly preferred embodiment of the invention, a gas vent with catalyst can be provided at the end of one or more reactor units for safety reasons.

[0058] The treated wastewater or the treated bromine-contaminated liquid can be fed into the preferred biological post-treatment after one, two or more treatment units (each consisting of an ultrasonic element, gas inlet and ultrasonic element / safety power converter).

[0059] In a special embodiment, an additional device is provided for measuring the initial bromide concentration upon introduction of the bromide-laden liquid into the reaction chamber. The measured values ​​can be transmitted to the control unit, where they can be further processed and used to adjust the reaction parameters.

[0060] Preferably, the proprietary (developed) algorithm can control the rotation speed of the cavitation element in such a way that optimal introduction of the gas mixture into the liquid is ensured.

[0061] Preferably, values ​​such as pressure, temperature, bromide concentration, oxygen quantity or concentration, ozone quantity or concentration, and / or pH value can be measured using various sensors and / or devices and linked to one another via a central control unit. This or another control unit can also be used to control various parameters such as flow rate, temperature, pressure, ozone concentration in the gas mixture or in the reaction chamber, frequency and / or intensity of the ultrasound and / or speed of movement of the cavitation element, as well as, if necessary, the switching on and off of the acoustic power converters, in particular the safety power converters. In this way, the reactions in the reaction chamber can be influenced.As already shown, this is important with regard to bromate formation, particularly over the duration of exposure of the bromide-contaminated liquid to the ozone-containing gas mixture.

[0062] In addition, a second ozone introduction unit or a downstream second or further reaction chamber can be controlled to provide potential residual elimination performance.

[0063] Especially under high or unexpected loads, the control of two or more reaction units provides additional protection against bromate formation, as the individual reaction times can be reduced.

[0064] Compared to conventional ozonation, this means a reduction in reaction times of approximately 20 times.

[0065] In a preferred embodiment, an analytical system for monitoring the bromide contamination of the wastewater is located in the inlet area of ​​the first tubular reactor. The data collected here also feeds into the process control system, allowing not only efficiency adjustments of the AOP process but also permanent, efficient hazard monitoring and management.

[0066] The arrangement of additional reaction chambers is possible in a modular manner. The process, using a single tubular reactor, is linearly scalable. Adjustments can be made modularly and do not require the construction of an entire new plant. The use of multiple reaction chambers does not increase the reaction time.

[0067] The invention further relates to a device for purifying a bromide-contaminated liquid by means of extended oxidation (AOP), comprising a reaction chamber, at least one mechanical cavitation element, and at least one supply device for ozone-containing gas. The device is characterized in that it additionally comprises at least one first acoustic power converter (reaction power converter) for supporting the oxidation reaction and at least one second acoustic power converter (safety power converter) for destroying any residual amount of ozone that may be present, as well as one or more ozone sensors and at least one control unit connected to the ozone sensor(s) and the supply device for ozone-containing gas. Preferably, the device also comprises a control unit connected to at least one acoustic power converter for regulating the amount of ozone-containing gas supplied to and / or present in the reaction chamber.

[0068] In one embodiment of the invention, the reaction chamber comprises at least one temperature sensor.

[0069] In a further preferred embodiment, the reaction chamber comprises at least one pressure sensor.

[0070] The reaction chamber is preferably arranged in a tubular reactor. In a particular embodiment, the tubular reactor comprises at least one additional reaction chamber. Example 1

[0071] In this example, the reaction chamber is arranged in a tubular reactor and includes an ultrasonic segment for breaking up the solid agglomerates and increasing the generation of hydroxyl radicals. Ultrasound is used to form cavitation bubbles. Within the cavitation bubble, water is homolytically split into H and OH radicals (Bober, U., 1998; Fang et al., 1996).

[0072] The reaction chamber also includes a gas introduction system similar to the mechanical cavitation element patented in EP2624943B1. This reduces ozone demand and reaction times. The reaction chamber also includes an additional ultrasonic segment / safety power converter after the gas introduction through the feed device.

[0073] The reaction chambers can be arranged in parallel or in series depending on the design requirements

[0074] The process according to the invention takes place in a fully controlled environment (pipeline). Additional reaction or retention tanks are not required. Example 2

[0075] 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, which leads to reduced reaction times and a lower requirement for ozone for comparable elimination performance.

[0076] The process according to the invention results in no significant amount of residual ozone being generated, which not only has positive effects on sustainability but also, and especially, on occupational safety for personnel. Unlike conventional ozonation, the entire process takes place not in reaction tanks, but in a sealed, highly compact tubular reactor.

[0077] The example concerns a plant comprising two redundant tubular reactors (tube cross-section 300 mm) connected in series, each with ultrasonic resonators (reaction power converters), a cavitation element (OptimiXer®), and downstream ultrasonic resonators (safety power converters). The reactors contain a degassing system to discharge the residual oxygen generated during the process to the environment via a catalyst to destroy any residual ozone, as well as a Primozone ozone generator (Löddeköpinge, Sweden).

[0078] The control system, pump, cooling system, and a VSA oxygen generator are located outside the reactors. The entire system is remotely controllable. Remote diagnostics and recording of process data and setting parameters for individual system components are possible. As an alternative to the VSA on-site oxygen generator, the oxygen demand for ozone generation is covered by cylinder bundles filled to 300 bar. Cooling for the ozone generator and a centrifugal pump for flow rates up to 50 m3 / h are also available.

[0079] The gas introduction is achieved exclusively through the usual operating pressure of the ozone generator.

[0080] For safety reasons, the plant includes protective devices for the release of ozone or oxygen from redundant catalysts and sensors for emergency shutdown and ventilation.

[0081] A sand filter is also available.

[0082] The proprietary, holistic system control system includes the elements measuring probes, pump, ultrasonic control and frequency, ozone generation, ozone input (rotation speed of the OptimiXer®) as well as safety elements such as gas sensors.

[0083] The main control variables in the system are ozone dose and volume flow. The adjustment of the individual control elements of the system is fully automatic.

[0084] The plant investigated the formation of undesirable bromate from bromide.

[0085] Bromide concentrations in the effluent were measured over the entire test period from 58 - 170 µg / L (n = 19).

[0086] The system has a flow capacity of 1 - 4 m3 / h with a pipe diameter of 100 mm.

[0087] Wastewater to be treated is filled in a 1000 L IBC container with a test volume of 535 L, which is treated in a closed-loop system with consecutively increasing dosages.

[0088] 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.

[0089] Since potential bromate formation also depends heavily on the specific ozone dose, this is also significantly increased during the experiments. While specific ozone doses of < 0.3 mgO3 / mgDOC are generally sufficient for normal operation of an AOP, in this experiment the specific ozone doses were increased to up to 1.3 mgO3 / mgDOC. The results are presented in Fig. 4. For clarity, the y-axis is plotted logarithmically. Analysis values ​​below the detection limit are shown as open points.

[0090] Further details can be found in the description of the figures, which represent preferred embodiments of the invention.

[0091] Showing: Fig. 1 a schematic diagram of the device according to the invention with a reaction chamber in the tubular reactor, Fig. 2 a schematic diagram of the device according to the invention with two reaction chambers 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 a pilot plant.

[0092] Fig. 1 shows the device according to the invention with a reaction chamber 1 in the tubular reactor 2.

[0093] The reaction chamber comprises a cavitation element 5 and two ultrasonic elements in the form of ultrasonic probes 4a and 4b, with one ultrasonic probe 4a being arranged upstream of the cavitation element 5 and the other ultrasonic probe 4b being arranged downstream of the cavitation element 5. In addition, the reaction chamber comprises at least one ozone sensor 6 and a supply device (not shown) for the ozone gas mixture.

[0094] The ozone gas mixture is introduced into the cavitation element 5 via a feed device. Between the cavitation element 5 and the downstream ultrasonic probe 4, at least one ozone sensor 6 is arranged, which determines the residual amount of ozone present in the reaction chamber 1.

[0095] A control unit 7 is arranged outside the reaction chamber 1 and is connected to the ultrasonic probes 4a and 4b, the cavitation element 5, and at least one ozone sensor 6. The control unit 7 is also connected to a bromide analysis device 8, which is arranged 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 influence the reactions, in particular the formation of bromates. This is preferably done by adjusting the ozone dose in the reaction chamber by setting or correcting one or more parameters. If necessary, a catalyst 3 for eliminating the gaseous ozone is arranged downstream of the reaction chamber.

[0096] Fig. 2 shows the device according to the invention with two reaction chambers 1 in the tubular reactor 2.

[0097] The structure of the reaction chambers 1 is identical to the structure of the reaction chamber from Fig. 1. The structure is modular and both reaction chambers are arranged one after the other in the tube reactor 2.

[0098] The 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.

[0099] Fig. Figure 3 shows the device according to the invention with a reaction chamber 1 in the batch process. The reaction chamber 1, like the reaction chambers 1 from Fig. 1 and Fig. 2. Through a closed circuit of the tubular reactor 2, the bromide-contaminated liquid can be fed into the reaction chamber as often as required. This is controlled by the control device 7. Once sufficiently purified, the bromide-contaminated liquid is removed from the circuit. This design enables the treatment of wastewater in a buffer tank 9 in a closed circuit. For this purpose, the contents of the buffer tank 9 are treated in one or more steps. This so-called batch process also enables decentralized treatment at specific locations, such as hospitals.

[0100] Fig.Figure 4 shows that no relevant bromate formation occurs at either high specific ozone doses or high initial bromide concentrations. During the investigations, bromate formation was detected only in isolated cases (2 of 22 samples), but these were within the drinking water limit. A systematic correlation between bromide concentration and ozone dose could not be established. Bromate formation was not detectable either at an exceptionally high initial bromide concentration (10 times) or at a theoretically high ozone dose (5 times). QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] EP 2125174B1

[0009] EP 2624943B1 [0012, 0029, 0072] EP 2794492B1

[0013] WO 2008 / 080618 A1

[0028] Cited non-patent literature

[0000] Brückner et al., 2018; DWA, 2022; Jahan et al., 2021; KOM-M.NRW, 2016

[0018] Bober, U., 1998; Fang et al., 1996

[0071]

Claims

[1] Device for purifying a bromide-contaminated liquid by means of extended oxidation (AOP), comprising a reaction chamber (1), at least one mechanical cavitation element (5) and at least one supply device for ozone-containing gas; characterized by that the device further comprises at least one first acoustic power converter (reaction power converter) (4a) for supporting the oxidation reaction and at least one second acoustic power converter (safety power converter) (4b) for destroying any residual amount of ozone that may be present, as well as one or more ozone sensors (6) and at least one control unit (7) connected to the ozone sensor(s), the feed device and at least one acoustic power converter for regulating the amount of ozone-containing gas fed into and / or present in the reaction chamber (1). [2] Device according to claim 1, wherein the reaction chamber (1) comprises at least one temperature sensor. [3] Device according to claim 1-2, wherein the reaction chamber (1) comprises at least one pressure sensor. [4] Device according to claims 1-3, wherein the reaction chamber (1) is arranged in a tubular reactor (2). [5] Device according to claims 1-4, wherein the tubular reactor (2) comprises at least one further reaction chamber (1). [6] Device according to one of the preceding claims, wherein a plurality of power converters (4) are arranged in front of the cavitation element (5) and are switched on and off intermittently at different times. [7] Device according to one of the preceding claims, wherein the amount of ozone in the bromide-contaminated liquid is measured by means of an ozone sensor (6) and the amount of ozone in the gas phase surrounding the bromide-contaminated liquid is measured by means of a further ozone sensor and the residual amount of ozone in the reaction chamber is determined by means of a program. [8] Device according to one of the preceding claims, wherein, in particular in the case of the presence of a residual amount of ozone, a further treatment with ultrasound is carried out by means of at least one further acoustic power converter (safety power converter) (4) to destroy the residual amount of ozone in the bromide-contaminated liquid. [9] Device according to one of the preceding claims, wherein the frequency and intensity of the ultrasound in the further ultrasound treatment is controlled by a control unit (7). [10] Device according to one of the preceding claims, wherein the frequency of the safety power converter or the average frequency in the case of several frequencies is lower than the frequency of the power converter or converters arranged in front of the cavitation element. [11] Device according to one of the preceding claims, wherein the introduction of the ozone-containing gas mixture is controlled by the control unit (7). [12] Device according to one of the preceding claims, wherein the time required for the liquid to be treated to travel from the mechanical cavitation element (5) to the safety power converter (4) in the application is less than 3 minutes, preferably less than 2 minutes and more preferably less than 1.5 minutes. [13] Device according to one of the preceding claims, characterized by that the ozone-containing gas mixture is an oxygen / ozone mixture.

Images