Ballast water treatment method and apparatus

[0001] The invention relates to the treatment of liquids, such as water, to remove unwanted matter.

[0002] There are many situations requiring the treatment of liquids, for example the treatment of sewage and drinking water, the treatment and processing of liquid hydrocarbons to break down undesirable long chain particles, the treatment of waste water from exhaust gas purifiers. More specific treatment processes are also used, such as water treatment from ballast tanks discussed below and water treatment for use in fish farming etc. The latter processes require the decomposition of undesirable matter in the form of organic matter, microorganisms and the like, usually to kill or inactivate them in such a way that the treated water does not have an undesirable effect on the environment in which it is introduced, or on the environment in which it is used.

[0003] Ballast water is water carried by ships in ballast water tanks or sometimes in other suitable places, such as holds or cargo tanks. It is pumped into the tanks at the "collecting" water in order to balance the shift of the center of gravity that occurs as the load and / or fuel is discharged and / or consumed, and thus to maintain stability. Correct ballasting is of fundamental importance from the point of view of design and is also used because of performance, to ensure proper submersion of the propeller and rudder, proper field of view from the bridge, as well as maintaining the desired parameters of movement and control of the unit. Ballast water is transported to a place of "returning" water, usually a place where the unit is to receive the load, which may mean a place outside the biogeographical region where the ballast water was collected. Ballast water may be discharged as the load is introduced on board. Ballast water can contain a whole range of organisms such as zooplankton, phytoplankton and bacteria. These organisms may not have natural enemies in the place of water discharge and may settle and reproduce in this place, causing serious threat to the natural environment, industry and human health.

[0004] Furthermore, corrosion occurs in ballast water tanks due to the reaction of ballast water and oxygen with the material of which the ballast water tanks are made. At present, costly paints and coatings are used to prevent corrosion, which results in high maintenance costs for sea transport.

[0005] Methods for purifying water using cavitation caused by ultrasonic excitation are known. For example, US 5,137,580 discloses a purification method that uses low and high frequency ultrasonic waves to create and enlarge cavitation bubbles. This treatment is carried out in static tanks, which means that a continuous treatment process is not possible and instead the tanks need to be emptied and refilled between treatment processes. As a result, this process is complicated and inefficient.

[0006] In addition to the disadvantages of using a static tank, ultrasonic cavitation is less effective than other methods of cavitation production, especially hydrodynamic cavitation. This is due to the smaller bubble size and lower cloud density for cavitation generated by ultrasound exposure than for hydrodynamic cavitation. Therefore, hydrodynamic cavitation has a higher effective response range than ultrasonic cavitation.

[0007] The use of Venturi orifices for the production of hydrodynamic cavitation is known, for example, from US 6,505,648. This document discloses a fluid flow culvert with a reduced diameter portion that creates a constriction that accelerates fluid flow and depresses pressure to initiate cavitation to eliminate contaminating organisms. A wire or rod passing through the constriction may be used to promote turbulence and further reduce pressure. Behind the venturi, the culvert expands rapidly, leading to cavitation bubbles collapsing.

[0008] However, this system has proved to be ineffective, since not all organisms in the liquid experience the effect of collapsing cavitation bubbles and, as a consequence, the water treatment process known in the art does not cover all water.

[0009] RU 2049072 discloses a water treatment device comprising a Venturi throat having a needle in the middle of the throat.

[0010] JP 2005-131613 discloses a method of purifying water using cavitation produced in an aqueous axial microturbine by ultrasonic excitation.

[0011] JP 2005-246198 discloses a ballast water treatment device in which a cavitation stream hits a target.

[0012] From the point of view of the first aspect, the invention provides a ballast water treatment device comprising a cavitation assembly, characterized in that the cavitation assembly is constructed in such a way as to create cavitation in water, by applying a flow of water through a venturi in which cavitation bubbles are formed and then through the outlet where the cavitation bubbles collapse, and characterized by that the orifice has a gap elongated along a normal direction of flow, the gap being not more than 5 mm wide and formed by circular walls forming a ring.

[0013] "Elongated" means that the gap is narrow in the transverse to normal direction and long in the normal direction. In particular, a gap of the greatest length and width of at most 5 mm, more preferably 1-2 mm, is used, as discussed below. This line can be straight or curved.

[0014] The use of an elongated narrow orifice allows cavitation to occur throughout

- 3 cross section of the liquid stream. This is due to the fact that cavitation usually begins around the edge of the orifice, and with a long narrow gap the greatest distance between any point of the stream and the edge is small. In contrast to the system of the invention, the venturi known in the art leads to cavitation concentrated at the edges of the tubular stream, and thus ineffectively used, which may not affect the entire liquid flow path. This is due to the fact that unwanted matter in the liquid is concentrated along the tubular stream, and thus in the region with the weakest cavitation. In the invention, due to the greater ratio of edge length to volume of the stream, the amount of cavitation in relation to the cross-sectional area of ​​the gap is greater, and the problem of undesirable matter draining into the low cavitation region is solved. The gap can thus alternatively be defined as a long-edge gap with respect to the surface to be covered.

[0015] The slit is a narrow ring, i.e. an elongated slot extending in a circular line. The use of a ring is preferred because it can easily be made in a circular tube, although an oval or other shape gap may be used as an alternative. It is advantageous to avoid corners for a smooth liquid flow.

[0016] The gap may have a width preferably less than 3 mm, in particular about

1-2 mm. The gap is preferably as long as possible along a normal direction of flow and may for example be at least 300 mm long with a width of 2 mm.

[0017] When the gap is a ring, the above width and diameter from 50 to 100 mm may be used. It has been found that this ensures efficient cavitation in a pipe of this size, especially when treating water to break down 1050 μm microorganisms, because a gap of 1-2 mm ensures that organisms of this size are usually located within one radius of the bubble from collapsing bubbles described earlier. The presence of organisms of this size in ballast water is prohibited by law.

[0018] Preferably, the cavitation assembly is constructed in such a way as to treat water by using cavitation to break down unwanted matter. The formation and implosion of cavitation bubbles create forces, temperature jumps, and shock waves that affect undesirable matter in the liquid. This undesirable matter may be organic or inorganic waste, for example in waste water or in water for treatment during the production of drinking water. Undesirable inorganic matter may include chain hydrocarbon molecules. In one preferred embodiment, the long-chain molecules are found in sewage on ships, in oils or sludge, or other hydrocarbon impurities.

[0019] In a preferred embodiment, the undesirable matter consists of aquatic organisms or microorganisms. As previously described, undesirable microorganisms are present in the ballast water used on ships, and thus, in a preferred embodiment, cavitation is used to treat the ballast water to break down such microorganisms.

[0020] Preferably, the cavitation assembly is constructed in such a way that at the point where the bubble implantation begins, the maximum distance from the bubble edge to undesirable matter is smaller than the bubble radius. This can be achieved by adjusting the gap width to the size of the unwanted matter. The implosion of bubbles is particularly effective when it occurs at a very short distance, and the distance smaller than the bubble radius has proved effective in providing the decomposition of undesirable matter, in particular microorganisms, by the effect of cavitation.

[0021] The annular gap may be formed by a cavitation object in the pipe, in particular by a generally cylindrical obstacle in the pipe. Therefore, the ring boundaries are the outer wall of the cavitation object and the inner wall of the pipe. The cavitation object may have a rounded end at the orifice inlet, for example, being a fragment of the sphere. The use of a rounded end to direct the liquid to the venturi results in a decrease in pressure and an increase in the flow velocity necessary to cause cavitation. At the outlet, the cavitation object may have a conical end. This promotes an increase in pressure and a decrease in flow velocity, supporting the implosion of cavitation bubbles while minimizing energy loss.

[0022] The gap wall may have an uneven or rough surface. This wall can be a wall of a pipe or a wall of a cavitation object, or both. Preferably, the cavitation object has an uneven or rough surface. This arrangement is easier to build and allows the use of a standard pipe without modifying its internal surface. The surface can be knurled or a well or well arrangement can be used. The use of an irregular surface promotes the effect of cavitation.

[0023] The cavitation assembly may contain multiple orifices, so that bubble formation and implosion will be repeated. For example, an annular gap with a wavy profile along the flow direction may be used, such as a wave profile or saw tooth profile. This can be achieved by using a cavitation object with a corrugated outer surface, placed in an ordinary cylindrical tube.

[0024] This device is used for the treatment of ballast water and, as the tank is filled or emptied, it exerts variable back pressure on the device. The efficiency of the cavitation assembly will be higher when the back pressure is kept above the minimum level. Therefore, preferably a pressure changing device is used to maintain the pressure exerted on the cavitation assembly at an acceptable level. For example, you can maintain a minimum back pressure of 1.5 bar or 2.5 bar, or you can maintain a back pressure in the range of 2 to 2.5 bar.

[0025] To ensure that all treated water is subjected to cavitation, the distance between the gap walls is limited by the size of the undesirable matter to be eliminated. Too large a gap will be ineffective, as the imploding cavitation bubbles will not be close enough to the unwanted matter. As a result, the size of the cavitation unit, and thus the maximum water volume that can be treated per unit of time, is limited. Accordingly, in a preferred embodiment, the device comprises a plurality of cavitation assemblies in a system such that liquid can flow in parallel through a number of cavitation assemblies. Cavitation assemblies can have different sizes. In one preferred embodiment, the system includes a large central bracket surrounded by a ring of cavitation assemblies. Cavitation assemblies may be smaller than the central bracket. The large central bracket may have the same shape as cavitation assemblies. The large central support can act as an additional cavitation unit. In another preferred embodiment, multiple cavitation units of equal size are used in concentric rings.

[0026] The use of the cavitation assembly system allows the treatment of large volumes without reducing the efficiency of cavitation treatment. The device may also include a manifold for directing the liquid evenly to each cavitation unit in order to obtain the same flow velocity through all the units.

[0027] The apparatus may include a cavitation monitoring hydrophone to obtain cavitation data, which cavitation data is used to control the system parameters of the cavitation assembly. The hydrophone detects pressure pulses caused by the cavitation unit, and the cavitation data can be used to control parameters such as flow velocity and pressure to optimize the operation of the cavitation unit.

[0028] The device may comprise an electric treatment assembly for treating the liquid before or after passing it through the cavitation assembly to weaken or damage undesirable matter in the liquid. The electric treatment team may apply an electrochemical effect, ionization, physical effect or any combination of these three. A water treatment device comprising an electrodialysis chamber, itself considered as an invention, is described below and can be used in combination with the water treatment device described above or as part of it.

[0029] The device may comprise a gas injection assembly, in preferred embodiments the injection assembly is for injecting nitrogen or oxygen containing gas into water. The oxygen-containing gas may be air. Nitrogen injection reduces the amount of oxygen in the water, which can reduce corrosion, as well as the aging of corrosion protection systems, such as coatings and paints, as oxidation is the cause of such aging. This is useful when the water is sent to the ballast tank, because otherwise the oxygen in the stored water can lead to corrosion or aging of the coatings. The tank could, for example, be coated with a single-layer polyurethane coating or other single-layer coating, but water treatment is also beneficial when using other coatings.

[0030] When the water is introduced back into the environment, for example when emptying the ballast tank, an oxygen-containing gas mixture, which may be, for example, air, can be used to introduce oxygen back into the water to avoid harmful effects on the environment. The gas injection assembly can be a nozzle located in the liquid flow path, behind which a static mixer can be placed. Alternatively, the gas injection assembly may comprise a combined gas and steam injection, as discussed below in relation to a water treatment device comprising an injection assembly, in itself considered to be the invention.

[0031] Preferably, nitrogen gas is introduced into the water by separating a portion of the water stream from the main stream, supersaturating this part of the water stream and returning the supersaturated water to the main part of the water stream. The amount of water separated from the main stream may be in the range of 5% -30% by volume, preferably less than 15% by volume. Due to the injection of a large amount of gas into a small volume of water, the flow after gas injection can be characterized by two phases. To improve gas-water mixing, a static mixer can be used in a separate water stream downstream of the gas injection point. To improve mixing of the two-phase stream with the main stream, a static mixer can be used at the point of connection with the main stream.

[0032] From the point of view of a second aspect, the invention provides a method of treating ballast water, comprising passing water through a cavitation assembly, producing cavitation by flowing water through a venturi in which cavitation bubbles are formed, and then through an outlet in which cavitation bubbles collapse, characterized by in that the venturi is a gap extending along the normal to the direction of flow, the gap is not more than 5 mm wide and is formed by circular walls forming a ring.

[0033] In preferred embodiments, the method of the second aspect of the invention comprises method elements suitable for the preferred features of the device discussed above.

[0034] Water treatment by means of an electric field is also known. The use of an electric field is based on a certain level of water conductivity, which may be responsible for pollutants in the case of "fresh" water or salts dissolved in seawater. In the case of electrochemical treatment, the presence of ions in water that will react to electric current is also required; these ions come similarly from impurities and salts dissolved in water. In the field of ballast water treatment, CN 1736798 uses an electrolytic treatment tank to produce oxidants and free radicals as well as to kill or inactivate organisms by the force of an electric field. All ballast water is treated in the electrolytic tank.

[0035] Electrodialysis is a known fluid treatment process that can be used to treat water for various purposes. The principle of this process is the separation of ions by applying a difference in electrical potential, constant or impulse, between two electrodes separated by a membrane, which can be ion-selective. One electrode will act as anode (positively charged), attracting negatively charged ions, while the other electrode will act as cathode (negatively charged), attracting positively charged ions. The fluid in the chamber between the membrane and the anode will be characterized by the presence of negatively charged ions having excess electrons and it can be determined as a concentrate, while the fluid in the chamber between the membrane and cathode will be characterized by the presence of positive ions with an electron deficiency and can be determined as a diluate . This configuration is known as an electrodializer.

[0036] In most practical electrodialysis processes, many electrodializers combine

- 7 in a configuration called an electrodialytic stack, with alternating anion and cation exchange membranes forming many electrodialytic chambers, usually between one anode and one cathode. The major known applications of electrodialysis are large-scale desalination of brackish and seawater, and salt production, as well as small- and medium-scale drinking water production. This process is also used in the processing industry to separate some impurities, such as heavy metals.

[0037] The electrodialysis systems may operate in a continuous or batch production system. In a continuous process, the diluate and / or concentrate flows through the appropriate number of stacks stacked in series to ensure the desired quality of the final product. In batch processes, the diluate and / or concentrate streams can be recycled and / or cross-processed by electrodialysis systems to achieve the appropriate product or concentrate quality. In each of these cases, the entire end product or end products are processed by means of electrodializers, either in a diluate or concentrate stream.

[0038] US 5540819 discloses a certain type of electrodializer for producing drinking water from fresh water contaminated with pathogenic microorganisms. The electrodializer is divided by a permeable membrane into two chambers containing anode and cathode, respectively. Direct current is passed through the water between the anode and cathode, and the water first flows through the anode chamber and then through the cathode chamber. All the water to be treated is passed through the anode chamber and then the cathode chamber.

[0039] The electrical treatment device that can be incorporated into the water treatment device described above comprises: an electrodializer; stream inlet to direct only part of the treated water through the electrodializer, and stream flow to direct product from the electrodializer to the remaining water.

[0040] By diverting the treated water in the electrode to the main water stream, all water after the electrode or after the discharge channel will be influenced by its parameters without the need for all electrical treatment. The product from the electrodializer has the property of inactivating or killing microorganisms and may also have a beneficial effect on the processing of organic compounds in water. The inventors have found that effective water treatment is obtained by passing only part of the water through the electrodializer and directing the product from the electrodializer to the rest of the water, without having to process the entire water stream through the electrodializer. Therefore, only a small amount of water needs to be treated in the electrodialyzer, instead of treating all the water using electrodialysis systems known in the art and described above. This reduces the amount of electricity needed for water treatment. Furthermore, the treatment device can be smaller compared to the water treatment systems known in the art, due to the relatively smaller amount of water treated in the electrode to achieve the effect of treating all the water. Any impact on the flow velocity of the main water stream is also kept to a minimum.

[0041] The part of the water treated in the electrode is preferably separated from the incoming water stream just before the treatment, and then passed through the electrode, when the rest of the water flows without treatment in the electrode. Therefore, the device may comprise a main flow stream in which an inlet is located to separate part of the stream from the main stream and direct it through the electrodializer. The device may comprise a connection of the electrode discharge outlet to the main stream, characterized in that the discharge channel introduces the product from the electrode into the main stream.

[0042] Water that is not treated by the electrodializer can be subjected to other treatment that can take place in parallel with the treatment in the electrodializer, for example cavitation treatment or nitrogen injection treatment as described in more detail below.

[0043] Preferably less than 5 vol% the total water stream entering the treatment device flows through the electrodializer, more preferably less than 1%, and even more preferably less than 0.5%. Amount about 0.2% by volume it is preferred, and depending on the conditions, only 0.05% or 0.01% can be used. The required volume of flux can be manipulated by changing the current used in the electrode and the salinity of the water. Thus, depending on these factors and the particular treatment application, the flow volume used may be larger or smaller.

[0044] As described above, this type of water treatment is particularly desirable for ballast water. Many existing water treatment techniques are unsuitable for ballast water treatment because of the large amount of water to be treated in a short amount of time. Since only part of the water needs to be passed through the electrodializer, and the rest of the water does not flow through the chamber, this treatment can be used for much more water at a given time than for alternatives requiring direct electrical treatment of all water.

[0045] The electrodializer may be used to produce the diluate stream and the concentrate stream, wherein the electrodializer product recycled to the water may consist of some or all of one or both of these streams. The product from the electrodializer can simply be a stream of concentrate produced by the electrodializer. Preferably, however, the electrodializer product is a mixture of the concentrate stream with at least a portion of the diluate stream. The concentrate stream contains an increased amount of various oxidants, and these oxidants are particularly effective in killing or inactivating microorganisms in water when the product from the electrodializer is recycled to the main water stream.

[0046] After the electrodialysis treatment, the concentrate may have a lower pH than the water before treatment, and the diluate may have a higher pH. Mixing the concentrate with part or all of the diluate thus allows the pH of the product to be adjusted from the electrodializer.

[0047] The concentrate stream and / or diluate stream may be produced by cross-processing or recirculation. Cross-processing means sequential treatment (one sequence, two sequences or more), in which the flow (from one chamber or both chambers) between the electrode membranes is recirculated through the opposite chamber, separated by the electrode membrane, can be used to change the characteristics of the concentrate and diluent and / or to reduce the amount of diluate and / or to simplify the final mixing of the two streams before re-entering the main stream. Similarly, the stream from the same chambers can be recirculated to change the characteristics of the concentrate and diluate before final mixing and reintroduction into the main stream.

[0048] In a preferred embodiment, the concentrate stream and at least a portion of the diluate stream are mixed immediately after passing through the electrodializer. This can be done by removing part of the diluate stream and then mixing the remaining diluate with the concentrate stream. The amount of diluate removed can be in the range of 40% to 60% by volume

[0049] In order to control the mixing ratio to maintain the pH of the concentrate or to mix the concentrate and diluate within the desired range, the pH of the concentrate, diluate and / or mixture is monitored. PH monitoring can be carried out by means of a pH electrode. The electrodialysis product preferably has a pH of 1 + 5, more preferably a pH of about 3. As a result, the pH of the main stream after addition of the electrodializer product is kept in the range of 7.0 to 8.5, which is similar to the pH of seawater. The pH of the electrode product can be controlled by varying the amount of diluate added to the concentrate, for example, by changing the amount of diluate removed before mixing. The pH of the concentrate is usually lower than the desired pH, so mixing with a high pH diluate portion can be used to increase the pH of the electrodializer product. PH control can also be accomplished by controlling the intensity or voltage of the current supplied to the electrodialyzer, thereby changing the strength of the resulting electrodialytic effect, and thus the concentrate oxidizing power.

[0050] The apparatus may include a diluate removal path for removing part of the diluate stream. To facilitate mixing of the concentrate and the diluate that has not been removed, the device may comprise a mixing zone upstream of the discharge channel. In one preferred embodiment, the mixing zone is a buffer tank. Alternatively, the concentrate and diluate can be mixed while flowing through the discharge channel. Mixing can occur at the same time as the concentrate stream and the uncoupled part of the diluate stream mix with the main stream, i.e. the product from the electrodializer can consist of two parts that only mix when the two parts are mixed with the rest of the water. In another alternative preferred embodiment, mixing is carried out by means of a bypass flow, for example using a static mixer or other mixing device, and the stream is then injected back after cavitation, where the pressure in the system is lower due to the pressure drop in the cavitation assembly. This arrangement avoids the need for a mixing tank or metering pump, and provides the ability to control and manage any gas bubbles from the electrodialysis process as described below.

[0051] Mixing can be facilitated by a static mixer or turbulence-inducing means in the mixing zone or stream outlet.

[0052] The removed diluate can be re-injected into the water before the electrodialyzer. When other treatment steps are also used, the remainder of the diluate is discussed below

Preferably injected before all treatment stages, and even before filtration and on the suction side of the ballast pump, if included in the system. Re-injection of diluate avoids the need for its removal and will react unhindered with impurities, unwanted material, etc. in incoming untreated water. Diluat can advantageously be used as a cleaning agent, in particular in filtration processes, if it is injected before filtration, or stored and used directly to clean the filters.

[0053] The characteristics and amounts of concentrate and diluate injected back into the main stream can be controlled by monitoring the redox potential (ORP) and / or consumption of available free chlorine (FAC). The range of desirable ORP values ​​may be 250 ^ 800 mV, more preferably 300 ^ 500 mV. Instantaneous initial FAC values ​​after re-injection are preferably between 2 and 4 ppm and drop to 0.1 + 0.4 ppm after one hour. FAC consumption strongly depends on the characteristics of the treated water. In order to optimize the operation of the electrodializer, it is desirable to create a calibration flow loop that allows you to pre-determine the current and mixing ratios before properly treating the water. When the measured ORP and / or FAC values ​​exceed the desired ranges, then the operation of the electrodialyzer is adjusted accordingly.

[0054] To direct the flow of water, the device may comprise channels, pipes, valves etc. The electrodializer may be included in the flow path of the main water stream, and therefore the device may comprise a main flow pipe or channel for the main stream, with smaller pipes or channels or the like similar, for directing part of the main stream through the electrodializer. Alternatively, the electrodializer can be provided as an autonomous device that can be connected to an existing water flow channel for water treatment. The treatment channel may be formed by a channel external to the main stream. This allows the existing water flow channel to be easily adapted to incorporate the treatment device by adding a suitable inlet and outlet fitting. In this case, the treatment device may comprise suitable pipes or channels for connecting the autonomous device to the existing channel, together with valves, dosing pump or dosing pumps etc. as required.

[0055] An independent brine source can be used to strengthen the electrolyte input to the electrode and increase its salinity. It may be, for example, brine, which is a by-product of fresh water production, or a product of a special brine production equipment, such as reverse osmosis plant. A reverse osmosis recirculation plant can be used to produce a saturated brine solution for use as an additive to the input electrolyte. The addition of brine or a similar substance is necessary when the system is used for the treatment of fresh water or slightly brackish water, otherwise the electrical treatment would not be effective due to the lack of ions in the water. Brine can also be added to low salinity seawater to bring the salt content in the electrolyte to a more favorable level. At a lower salt content, more current is needed to achieve the same result of the electrodialysis treatment. Consequently, by increasing the salt content, a reduction in energy consumption can be achieved. For example in

- 11 North Sea salinity of 25 per mille or higher is typical, while in the Baltic Sea surface water has a much lower salinity, perhaps 7 per mille. Preferably, the brine is added to the electrolyte input to the electrodeizer to maintain salinity of at least 25 per mil.

[0056] Preferably, after treatment, the water is stored for some time in a reservoir or tank. This gives the oxidants and reactive substances contained in the electrodializer product time to exert full influence on all microorganisms and other undesirable matter in the water. In a particularly preferred embodiment, the invention is used in the treatment of ballast water for ships, where the water is treated at the time it is taken into the ballast tanks and then stored in the ballast tanks before discharge. In such circumstances, water is usually stored long enough when the ship moves from port to port before reloading and releasing ballast water. This time can be advantageously used, allowing the water to be treated by the electrodializer product.

[0057] To enable treatment of a large amount of water, electrodialysis is preferably provided by multiple electrodializers in parallel, instead of one larger electrodializer. This enables a more modular design and simplifies the construction of each electrodializer, reducing the complexity and size of parts.

[0058] The treatment may include gas injection. In preferred embodiments, a gas injection assembly for injecting nitrogen and / or oxygen-containing gas into the water is provided. The oxygen-containing gas may be air.

[0059] Oxygen injection can be used to restore the appropriate level of oxygen in the water before releasing water from the tank into the environment, for example, before emptying the ballast tank into the sea.

[0060] Turbulence resulting from gas injection can be used to improve mixing of the electrodializer product with the main stream.

[0061] Preferably, the cavitation assembly for water treatment is placed before the product from the electrodializer is returned to the stream. Therefore, cavitation treatment can be used to eliminate larger and more complex organisms, as well as to break up other undesirable matter, in particular to break up groups or clusters of microorganisms, while the product from the electrodializer will provide the final level of treatment, eliminating all other organisms, and will be able to act more effectively because larger size organisms and groups of organisms have been broken down. The turbulence resulting from cavitation treatment can be used to facilitate mixing of the electrodializer product with the main stream.

[0062] The electrodializer may advantageously be arranged parallel to the cavitation assembly. In this case, a small amount of water flows through the electrodializer, and the main part of the water flows through the cavitation assembly. Preferably less than 5% by volume the total water stream entering the treatment device flows through the electrodializer, more preferably less than 1%, and even more preferably less than 0.5%. Amount about 0.2% by volume

- 12 is preferred, and amounts as low as 0.05% or 0.01% can be used depending on the conditions. The product from the electrodializer is fed back into the main stream after the cavitation assembly.

[0063] Although this means that a small part of the water is not treated by the cavitation unit, the overall treatment efficiency does not change significantly, and the benefit of placing the inlet and outlet of the electrodialyzer on opposite sides of the cavitation assembly is that the pressure drop in the cavitation assembly provides a pressure difference that drives the flow through the electrodializer, which avoids the use of a separate pump and makes the system work automatically in a closed circuit. The resulting use of a pressure electrode has additional benefits by reducing or eliminating the production of hydrogen gas during electrical treatment. The production of hydrogen gas is a well-known risk associated with water electrodialysis. Hydrogen, although it can be generated, is always kept in a safe dissolved state when using a pressure electrode.

[0064] When using a pressure electrode, a suitable membrane must be selected to allow the process to be carried out under pressure. Preferably, the electrodializers are built using a ceramic membrane. Such membranes work more effectively under pressure than other types of membranes.

[0065] The method described above may include electrical treatment, comprising: flowing only part of the water through the electrodializer and introducing the product from the electrodializer back to the rest of the water. In preferred embodiments, the method includes elements corresponding to the preferred features of the electric treatment device described above.

[0066] In a particularly preferred embodiment, the method comprises: treating the water used to fill the ballast tank by means of the electrical treatment described above, injecting nitrogen into the water, storing treated water in the ballast tank, discharging the water from the tank and introducing it into the environment. The method includes creating cavitation in water when water enters or is discharged from the reservoir. Preferably, cavitation is used to treat the water before introducing the electrode product back into the water.

[0067] In a preferred embodiment, the method comprises treating the discharged water by injecting an oxygen-containing gas before discharging it into the environment. The oxygen-containing gas may be air.

[0068] The water treatment device may comprise an electric treatment assembly for treating the water with an electric current, characterized in that the water flows in parallel through the electric treatment assembly and the cavitation assembly. By combining electrical treatment and cavitation, all organisms, in particular microorganisms in water, as well as other types of unwanted matter, can be more effectively broken down. The parallel flow allows water to be pumped through the electric treatment unit under the influence of pressure drop in the cavitation unit. The electric treatment assembly preferably comprises the elements of the electric treatment device described above.

[0069] The method of water treatment may similarly include: separating the water stream into two parts, treatment of one part by an electric treatment assembly, treatment of the other part in parallel by a cavitation assembly and reassembly of these two parts. The electrical treatment preferably takes place according to the electrodialysis process described above, in which electricity is used to cause chemical reactions in water, which chemical reactions lead to further treatment of the water in the combined water when the electrically treated water is recombined with the remaining water.

[0070] Preferably the method comprises: treating the water used to fill the ballast tank as above by means of the nitrogen injection gas injection unit, storing the treated water in the ballast tank, draining the water, optionally treating the drained water by repeating the cavitation and / or injection steps gas by means of an air injection gas injection unit, and discharging water into the environment.

[0071] The devices and methods of all the embodiments described above can be installed in existing water treatment devices or in systems where it is desirable to add a water treatment device.

[0072] Preferred embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings, in which:

Figure 1A is a diagram of a water treatment system equipped with an external electrode;

Figure 1B is a diagram of a water treatment system equipped with an embedded electrode;

Figure 1C is a diagram of a water treatment system with an electrodialyzer parallel to the cavitation assembly;

Figure 2 shows an embodiment of the cavitation assembly;

Figures 3 ^ 5a show different cavitation objects with different ways to attach a cavitation object to a pipe;

Figures 6 ^ 9 show various alternative shapes of the cavitation object;

Figures 10 and 11 are graphs of pressure versus distance along the cavitation assembly for the cavitation assembly of the type shown in Figure 8;

Figure 12 shows two embodiments of cavitation assembly systems to increase the amount of water that can be treated;

Figure 13 is a cross-sectional view of the arrangements of Figure 12;

Figure 14 shows the position of the injector in the pipe;

Figure 15 is a diagram of details of a gas / steam injector;

Figure 16 shows an alternative alignment of the injector;

Figure 17 is a diagram of a static mixer in a pipe;

Figure 18 shows a possible configuration of a static mixer;

Figure 19 is a partial perspective view of the electrodializer, and

Figure 20 shows an alternative orientation of the electrodialiser in a partial perspective view.

[0073] The embodiments of Figures 1A and 1B are intended for use as a ballast water treatment system and are therefore described below in this context, but it will be appreciated that there are other uses of the described system and that this system can be adapted to meet different requirements.

[0074] Figure 1A shows a first embodiment of a treatment system. The water is filtered and then treated by the cavitation unit 10, gas injection unit 14 and electrodializer 8. This combination of treatment causes damage and death of the organisms in the water. In addition to affecting organisms in water, the nitrogen added to water by the injection unit 14 reduces the level of dissolved oxygen in water and reduces the possibility of re-development of organisms, as well as coating aging and corrosion rate. In addition, it is resentful that lowering the oxygen content prolongs the effect of oxidants introduced into water through the product from the electrodialyzer 8. These effects are further enhanced by the controlled atmosphere management of empty ballast tanks with nitrogen.

[0075] When filling the ballast tanks, the ballast water is pumped from the sea through the inlet pipe 1 using the ship's ballast pump system 2. After the pump 2, the water flows through the pipe and is filtered through the first filter 4, which filters larger particles from the water. These particles form a sludge that is discharged at the ballast collection point.

[0076] A pressure booster may optionally be installed after the first filter 4. The pressure booster can be used to maintain the water pressure needed for proper treatment in devices farther away.

[0077] Water then flows further to the cavitation assembly 10. In the cavitation assembly 10, hydrodynamic cavitation is induced by rapidly accelerating the flow of liquid, which allows the static pressure of the liquid to rapidly decrease to the vapor pressure. This in turn leads to vapor bubbles. After a controlled time to allow bubbles to rise, there is a rapid controlled decrease in speed. This causes a rapid increase in the static pressure of the liquid, which results in a rapid collapse, i.e. imploding of vapor bubbles, so that all organisms etc. in the water are subjected to high pressure pressure and temperature pulses, which in turn break down the organisms in the water. Cavitation assembly 10 is described in more detail below with reference to Figures 2 + 13.

[0078] Behind the cavitation assembly 10 some of the water flows through the electrodializer 8. The rest of the water is not treated in the electrodializer 8 and can simply flow further through a pipe or channel for further treatment steps. In the embodiment of Figure 1A, the electrodializer is mounted externally to the main stream channel, so that it can be installed in an existing water treatment system.

[0079] In an alternative embodiment, instead of or in addition to the treatment of collected ballast water, another source of brine or salt water 24 may be used in the electrodializer 8 as the input electrolyte for the electrodializer 8. This may be brine as a by-product of the production of fresh water or a product of a special production device brine, such as reverse osmosis plant.

[0080] A source of brine or salt water can also be used to increase the salt content of the water when the system is used to treat fresh water or lightly brackish water. As described earlier, this enables the electrodialysis of water, which otherwise could not be treated, and can also be used to reduce energy consumption.

[0081] The electrodializer 8, which is described in more detail below with reference to Figure 19, produces a diluate stream 11 and a concentrate stream 12. These two streams pass to the pH equalizing or mixing device 13 producing the product from the electrodializer 17, directed back to the main stream water, and depending on the composition of the product 17, the mixing device 13 can also discharge the rest of the diluate 18. The mixing device 13 comprises a pump or the like for controlling the amount of diluate 11 added to the concentrate 12 to obtain an optimal product from the electrodializer 17. In an alternative system, as described earlier, the mixing device may be in a closed pressure circuit, with pressure provided by the drop pressure on a parallel cavitation unit. In this case, no pump is required.

[0082] Behind the injection point of the product from the electrodializer 17 is the measuring and sampling point 15, which measures ORP and / or FAC, and transmits the measured values ​​to the mixing device 13. These measurements monitor the effect of the electrodializer 8 on water and are used to control parameters electrode operation and / or mixing ratio used.

[0083] The rest of the diluate 18 can be injected into the incoming water before all treatment steps and preferably also before the filter and / or ballast water pump. Alternatively, it may be stored in the cargo tank 25 or in the bilge water tank of ship 26.

[0084] In the embodiment shown, the gas injection assembly 14 treats water after introducing the product from the electrodializer 17 back into the main stream. However, in alternative embodiments, the product 17 is fed back into the main stream downstream of the gas injection unit 14, with the monitoring device 15 also downstream of the gas injection unit 14, monitoring the state of water after adding product 17.

[0085] In the gas injection unit 14 into the incoming water, nitrogen gas is injected with the aid of a steam-nitrogen injector or gas / water mixer 16 to achieve the desired level of nitrogen supersaturation, which kills organisms and reduces corrosion by reducing oxygen levels. It also extends the treatment effect of oxidants in water. The embodiments of the injection assembly 14 are described in more detail below with reference to figures 14 + 18.

[0086] Behind the treatment units, the treated water is distributed through the ballast water pipeline of the vessel 23 to respective ballast water tanks. Here, excess gas is discharged to achieve stable conditions. This is regulated by valves built into the tank ventilation system. These valves ensure stability of conditions in the tank while ballast water remains in the tank, in particular high level of nitrogen supersaturation and low level of oxygen dissolved in the water. Maintaining the level of supersaturation leads to the continuation of water treatment both by supersaturation and by the oxidants introduced by the electrodializer 8. Therefore, the treatment leads to receiving treated water that still kills or inactivates organisms while the water is stored in the ballast tanks and acts as a measure to prevent re-development.

[0087] Then the water is left in the ballast water tanks. When ballast water is discharged, it is subjected to a discharge treatment process that restores the oxygen content of the water to an acceptable level for ecological reasons for the purpose of discharging. Water is pumped from the ballast tanks and it flows through the gas injection unit 14. This is used to re-introduce oxygen into the water as the air replaces nitrogen as injected gas. Alternatively, the water may be re-treated in cavitation assembly 10 during discharge.

[0088] A second embodiment of the treatment system is shown in figure 1B. This is generally the same embodiment as that of figure 1 A, but the electrodializer 8 is built into the main stream instead of outside. Water flows through the electrodializer 8 as described in more detail below with reference to figure 20. In this embodiment, the mixing device 13 can be installed as part of a built-in electrodializer. As in the embodiment of Figure 1A, the electrodializer 8 produces a diluate stream 11 and a concentrate stream 12 by treating part of the water. The rest of the water is allowed to flow through the built-in electrodializer 8 without treatment and is mixed with the product from the electrodializer 17 as described above. You can also use an external source of salt water or brine 24.

[0089] As described above with reference to figure 1A, as an alternative to the embodiment of figure 1B, the gas injection unit 14 may inject gas before the point where the product 17 mixes with the main water stream. This can be accomplished by injecting gas before the electrode treatment inlet, or the gas injection assembly 14 can inject gas into a water stream that is not treated by the electrodializer 8, and thus the electrodialytic treatment of some water and nitriding of the rest of water can occur in parallel.

[0090] A further arrangement of the elements of the water treatment system is shown in figure 1C. In this system, the water is pumped through the inlet 1 by means of the ballast pump 2, and then filtered through the first filter 4 as described above. The water stream is then separated and a small part, about 0.2% by volume, is directed through the electrodialyzer 8 and the rest is passed through the cavitation assembly 10. It should be noted that the electrodializer operates as described with reference to Figures 1A and 1B, and that there may be other elements associated with the electrodializer 8 as shown in Figures 1A and 1B, such as cargo tank 25 or marine bilge water tank 26 .

[0091] After the electrodializer 8 and cavitation assembly 10, the product 17 from the electrodialysis assembly 8 mixes with the water treated by the cavitation assembly, and this water then flows into the gas injection assembly 14. In this embodiment, a gas injector acting only on part of the water stream is shown, not built into the water jet as in figures 1A and 1B. It should be noted that the gas injector system 14 can be exchanged between the embodiments of Figures 1A, 1B and 1C. In the system shown in Figure 1C, nitrogen is injected into a part of the water stream that is less than 15 vol%. total, maybe 10% vol. Nitrogen is injected in an amount sufficient to ensure that the water is saturated with nitrogen. When the nitrided water stream is reintroduced into the main water stream, turbulence from the joining streams or alternatively from a static mixer, is used to facilitate mixing of the two water streams and ensure that the entire water stream is sufficiently nitrided to achieve the desired water treatment effect.

[0092] After the introduction of nitrogen, the treated water flows through the pipe 23 into the ballast tank, where it is stored. As in the above embodiments, when it is necessary to release water from the ballast tank, the system is configured so that the outflowing water is directed through a treatment process, including the introduction of oxygen to re-oxygenate the water, and possibly re-cavitation treatment.

[0093] Figures 2 + 13 show embodiments of the cavitation assembly 10. Cavitation is a liquid nucleation process caused by a decrease in local static pressure below the local vapor pressure at a constant temperature. A decrease in local static pressure causes the liquid to boil, which leads to the formation of small vapor bubbles. An increase in static pressure causes these vapor bubbles to collapse.

[0094] In the last stage of collapse of the bubble, high pressure is generated, which according to the literature leads to the formation of a shock wave. The shock wave can be initiated at a speed of almost 4000m / s and a decrease in the shock amplitude faster than 1 / r. It has been reported that the pressure pulse near the follicle in some cases reaches 1 GPa. There are also reports in the literature of high local temperature points up to 7800K, resulting from the collapse of the cavitation bubble. If cavitation occurs near the rigid surface, the bubbles collapse asymmetrically, often creating a rapidly moving stream of water. This stream can damage the surface and probably leads to tissue damage when an organism etc. is near the collapsing bubble. Streams, high pressure and temperature created by the collapse of cavitation bubbles have a destructive effect on microorganisms in water, causing damage to the tissues of organisms, which in turn leads to the death of organisms.

[0095] However, fast moving water jets and high pressure points and

- 18 temperatures occur in close proximity to the collapsing bubble and thus only affect organisms that are close enough to the bubble at the time it collapses. To use the energy generated more efficiently during bubble implosion, target organisms should be targeted. In the case of water treatment methods in general, and in particular ballast water treatment, this can be achieved by causing cavitation in a small gap through which the treated water flows, or in the vicinity.

[0096] In the preferred cavitation assembly, hydrodynamic cavitation is induced by a rapid controlled acceleration of the liquid, which allows a rapid decrease in the static pressure of the liquid, which leads to the formation of vapor bubbles. After a controlled time allowing the bubbles to grow, there is a rapid controlled inhibition. This causes a rapid increase in the static pressure of the liquid, which causes a rapid collapse, i.e. imploded vapor bubbles, subjecting the organisms to high pressure and temperature pulses.

[0097] The geometry of the cavitation assembly 10 was designed to utilize the observed synergistic effects of the presence of the surface with respect to bubble formation and the importance of the implication bubble proximity to the target. Various structure configurations with different characteristics, including repetitive cavitation, were all developed based on the same favorable geometry design.

[0098] The cavitation assembly 10 creates peripheral cavitation around the torpedo-shaped cavitation object 30, as shown in figure 2. The torpedo-shape 30 is preferred because it is substantially cylindrical and can easily be placed in a pipe 31, such as a ballast water pipe or any other water pipe. The specific shape of the torpedo 30 can be designed to provide adequate pressure drop to induce maximum cavitation in any circumstances. Preferred shapes optimize bubble growth and granulometric composition, in particular to bring microorganisms near the cavity collapse zone to achieve the maximum destructive effect of the cavitation unit 10.

[0099] The basic parameters of the torpedo 30 of Figure 2 that can be manipulated are length A, radius B, gap width C, angle D, torpedo bow radius E and length of the central part of torpedo F. These parameters can be changed to achieve specific cavitation characteristics . Generally, the cavitation assembly 10 is configured to provide an elongated area in which cavitation is induced by the narrowing of the flow path, which is achieved in this embodiment by a narrow annular channel. In figure 2 the liquid flows from left to right. The water speed is higher and the pressure is lowered at the torpedo E bow, which causes the cavitation bubbles to rise. The bubbles grow along the center of the F torpedo and then implode when the water pressure increases again.

[0100] Figures 3 ^ 5a show four different versions of the cavitation object 30, showing how to mount the torpedo assembly in a ballast water or sewage pipe 31.

[0101] Figure 3 shows the fins 32 used to attach the torpedo 30 to the pipe 31.

- 19 Length, angle, height, depth and number of fins 32 can be changed.

[0102] Figure 4 shows bolts 33 used to attach the torpedo to the pipe. Bolts 33 are attached to torpedo 30 at the front and rear ends of the assembly. The length, diameter, position and number of pins 33 can be changed.

[0103] Fins 32 and pins 33 are constructed to ensure that torpedo 30 is permanently attached to the water tube 31. In addition, the design is such that they affect the cavitation zone as little as possible so that the torpedo assembly 30 provides the maximum possible cavitation.

[0104] Figure 5 shows both pins 33 and fins 32 used to attach torpedo 30 to tube 31. Four pins 33 are attached to the torpedo assembly at the front end of the assembly and four fins 32 are attached to the torpedo assembly at the rear of the assembly.

[0105] Figure 5a shows a torpedo 30 with an alternative design in which the torpedo 30 is held in place by projections 52 that slide into the brackets. The protrusions 52 eliminate the need for pins or fins, and thus avoid obstacles in the path of water flow other than the torpedo itself, thereby promoting a more even flow of liquid.

[0106] Figures 6 ^ 9 show different alternative torpedo designs 30. Figures 6 and 7 show two different simple versions of the torpedo 30, providing two different options for attaching the assembly to the water pipe. In particular, Figure 7 shows a torpedo 30 with a blunt trailing edge 34, which can be used to more easily attach the rear end of torpedo 30 to tube 31. The simple version of torpedo 30 causes cavitation by causing a single rapid decrease and increase of pressure along the assembly and the cavitation zone at the end of the central part of torpedo 30.

[0107] In addition to the simple version, there are two more versions of the torpedo assembly, as shown in figures 8 and 9. These two versions may have a rear portion of the assembly designed as shown in figure 6 or figure 7.

[0108] Figure 8 shows a torpedo with a wavy profile 35, forming a plurality of cavitation zones due to repeated pressure drop and increase. For the torpedo 30 of Figure 8, cavitation implosion zones are obtained for each wavy section of the assembly. This is beneficial because the destructive cavitation effect is repeated on each section.

[0109] Figure 9 shows a torpedo 30 with an irregular surface segment 36. This surface may be, for example. knurled surface or recessed surface. The use of an irregular surface 36 improves bubble generation due to depressions on the surface of the torpedo assembly 30.

[0110] Figures 10 and 11 show the vapor pressure profiles for two different torpedo designs 30 in the version with corrugated surface shown in Figure 8. The graphs depict pressure on the vertical axis and the horizontal axis shows the distance along the cavitation assembly. The low pressure points are below atmospheric pressure P. The diagram in figure 10 shows the pressure profile for a torpedo 30 with two folds, i.e. one less than the torpedo shown in figure 8. The graph in Figure 11 shows the pressure profile for

20 torpedo 30 with three folds, such as torpedo 30 of figure 8.

[0111] The number of folds in the middle part, the position of the folds in the middle part of the torpedo and the minimum and maximum fold diameter can be varied to achieve the desired cavitation effect. These parameters are selected to obtain the maximum number of cavitation zones and the maximum surface / volume of cavitation.

[0112] It will be appreciated that the features of Figures 6 + 9 can be introduced in torpedoes 30 with the same general shape shown in any of Figures 3 + 5a as well as in other shapes of the cavitation object.

[0113] Figure 12 shows two different versions of the arrangements 37 of multiple cavitation assemblies

Ten. They show how a standard cavitation unit 10 can be extended with a number of units to provide different ranges of possible flow rates. These versions should allow more control and flexibility than the single torpedo version, which is limited by the need to keep a narrow ring to maximize the cavitation effect. Due to the presence of multiple cavitation assemblies, the effectiveness of the cavitation effect can be maintained without limiting the use of higher flow rates.

[0114] In one version, the large 10 'torpedo is located in the center of the water pipe 31, while smaller 10 ”torpedoes are placed around the large torpedo. Smaller 10 "torpedoes generate cavitation as described above. The large 10 'torpedo can simply form the basis for smaller 10 "torpedoes and in this case would not cause any cavitation, although the front and rear ends of this torpedo are shaped to direct the water jet towards smaller 10" torpedoes. Alternatively, the large 10 'torpedo can operate in the same way as the smaller 10 ”torpedoes and the 10 torpedoes described above to create cavitation for water treatment. The diameter of the new X assembly may be equal to, smaller or larger than the diameter of the water pipe Y. The X / Y ratio depends on the desired water flow speed and the number of torpedo assemblies used in the multi-unit versions.

[0115] In an alternative version, a number of small 10 "torpedoes are mounted in the water pipe 31 without using a larger 10 'assembly. In the embodiment shown, the smaller 10 "torpedoes form two concentric rings around the central 10" small torpedo.

[0116] Figure 13 shows cross sections of the arrangements of Figure 12, with more or fewer smaller cavitation units 10 ". A different number of small 10 "torpedoes can be placed in the assembly, depending on the flow rate required.

[0117] Figure 14 shows a gas injector assembly 14 comprising an injection nozzle 43 disposed in the pipe 31. Nitrogen 16 or air 29 is injected into the water jet channel. Steam may also be injected 38 to improve the mixing of gas 16, 29 with water, as discussed below. Gas can be introduced into water by means of the gas / steam injection nozzle 43 as shown in figure 15, gas injection into the venturi nozzle in pipe 31 as shown in figure 16, or a gas / water static mixer 44 as shown in figures 17 and 18 The elements of figures 16 + 18 are known gas mixing systems that can be used in the described water treatment device. In the described water treatment process

21 nitrogen 16 is injected through the injector assembly 14 during the refilling stage for treatment and air 29 is injected during the deflation stage during treatment.

[0118] As described earlier, gas injection and in particular nitrogen injection can only be carried out on a part of the water stream instead of injecting the gas into the entire water stream. The gas injector assemblies described in the document could, of course, be placed in the main water stream, as in Figures 1A and 1B, or could be placed in a separate water stream, with which only part of the water flows before being connected back to the main stream, as in Figure 1C.

[0119] In preferred embodiments, steam 38 is injected at the same time as gas 16, 29 as in Figure 14. The use of steam 38 aids in mixing gas 16, 29 with water and reduces the amount of gas 16, 29 required. In addition, injection steam creates a pumping effect. This is because the injection of steam leads to a faster stream behind the injection point, which accelerates the liquid, creating additional suction, which is felt by the system as an additional pumping effect. In addition, the injected steam creates pressure pulses that affect any undesirable matter present in the water, and provide the physical effect of water treatment in addition to the effect of the gas / steam injector on the amount of gas dissolved in the water.

[0120] In order to achieve the best effects of steam and gas injection, certain requirements for the construction of the injector must be met. These include appropriate steam condensation regimes, the production of a fast two-phase stream, appropriate gas bubble sizes, and avoiding clogging of the injector.

[0121] Water vapor condenses into water in different regimes, depending on the amount of water vapor injected, the temperature difference between water vapor and water, the diameter of the water vapor injector, and the amount of impurities / gas in the water vapor. There are three main regimes for condensing water vapor into water. These are knocking, bubbling and injecting. Individual regimes have a different effect on gas and water mixing. The most desirable regime from the mixing point of view is injection. In general, injection is effective when the amount of steam injected exceeds 150 kg / (m²s).

[0122] In a two-phase stream, steam injected into the water produces a stream after the injection point. The stream improves the mixing of gas and water and provides an additional pumping effect.

[0123] If the diameter of the exit from the injector is too small, the steam begins to clog the injector. Steam clogging makes the mixing process difficult and should be avoided.

[0124] The gas may be mixed with steam before injection. The gas in the steam reduces the condensation rate, since most of the gas is forced out onto the surface of the condensing water vapor, which must therefore condense through the gas layer. However, if the amount of gas is too high, the water vapor condenses inside the injector mixing chamber, which reduces the effect on mixing.

[0125] The range of gas bubble sizes also affects mixing efficiency. This range depends on the amount of steam injected, the amount of gas injected, water and gas temperature, pressure and condensation regime, etc.

[0126] Figure 15 shows a preferred design of the steam / gas injector nozzle 43. The parts are shown in close-up. The nozzle element 43 of figure 15 is small compared to the size of the pipe 31 and would be placed in the center of the pipe 31 as shown in figure 14.

[0127] The injector nozzle 43 consists of three main parts. In the inlet zone 40, steam 38 and gas 29, 16 are fed to the injector nozzle 37. The injector nozzle 43 is formed of a small pipe 45 inside the larger pipe 46. Steam 38 is fed through a small pipe 45 in the middle of the injector nozzle 43, and the gas 29 , 16 is given in the area around the steam pipe, between the larger pipe 46 and the small pipe 45. Water flows outside the larger pipe 46.

[0128] Behind the inlet zone is a mixing zone 41, where water vapor 38 and gas 29.16 are mixed. In Figure 15, the mixing zone is formed by the tip of the small pipe 45 and the continuation of the larger pipe 46. The gas / steam mixture is injected into the water stream through the divergent constriction zone 42 of the injector nozzle 43. The overall length of the injector, the length of the individual injector zones, the narrowing angle, the radius of the main pipe 46, the injector outlet and the radius of the steam pipe 45 can be changed to achieve the desired mixing effect.

[0129] Water is present in the injector nozzle 43 prior to the administration of steam and gas. Steam and gas are also not completely mixed in the mixing chamber before being injected into the water. In order to achieve complete mixing, different injector designs can be used with the tapering zone instead of the tapering 42. However, this design provides no or little clogging of the injector nozzle 43, which increases mixing efficiency.

[0130] Figure 16 shows an alternative gas injector assembly 14. In this system, gas

29.16 is injected into the stenosis in tube 31.

[0131] Figure 17 illustrates the use of a static mixer 44. A static mixer 44 is mounted in the middle of a water stream. Gas 29, 16 is fed to the water stream upstream of the mixer and mixed with water due to turbulence during flow through the mixer 44. The gas can be fed using nozzle systems as previously described or through alternative conventional systems.

[0132] An example of a static mixer 44 is shown in Figure 18. An annular turbulent flow of a highly mixed multi-phase liquid through a static mixer 44 is achieved by joining separate plates as shown. The external circuit of the static mixer is circular, which allows the installation of the system in pipe 31.

[0133] The operation of the electrodialyser 8 will now be explained. The embodiments of the construction electrodialyser systems 8 are described below with reference to figures 19 and 20. For each of these embodiments, the chemical processes are essentially the same. As described earlier, electrodialysis is an electromembrane process in which ions are transported through ion-permeable or ion-selective membranes in a liquid system. In the simplest version of an electrodializer, a single membrane or pair of membranes are placed between two electrodes. Electric charge generated by applying voltage

- 23 between two electrodes, allows ions to pass through the membrane, as long as the liquid conducts current. The voltage is applied using a conventional type of power supply connection that is not shown in the drawings. The two electrodes are anode and cathode, respectively. Electric charge causes various reactions on individual electrodes. On the anode, the electrolyte will be acidic, while on the cathode the electrolyte will become alkaline. The membranes used in electrodialysis are selected for their ability to be transported selectively. Therefore, this allows the alkaline solution to be separated from the acidic solution.

[0134] The various reactions that occur in the electrode when the incoming electrolyte is ballast water taken from the ballast water pipeline (i.e., seawater) is shown in Table 1 below. The raw electrolyte can therefore have such properties as conductivity, which changes the effects of the electrodialysis process.

Table 1

Anode reactions:

2Cl^- - 2e> Cl2 2H2O - 4e> 4H + + O2

Cathode reactions:

2H2O + 2Na + + 2e> 2NaOH + H2 2H2O + 2e> H2 + 2OH^-

cl₂ + H2O> HClO + HCl O2 + e> O₂

HCl + NaOH> NaCl + H2O O2^- + H +> HO2

cl^- + 2OH^- - 2e> ClO^- + H2O O2 + H2O + 2e> HO2^- + OH3OH^- - 2e> HO2 + H2O O2 + 2H2 + 2e> H2O2 + 2OH^-

HO2^- - e> HO2 H + + e> H *

OH^- - e> OH * H * + H *> H2

OH * + OH *> H2O2 OH * + OH *> H2O2

HClO + H2O2> HCl + O2 + H2O H2O2 + OH *> HO2 + H2O ClO^- + H2O2> O2 + Cl * + H2O H2O2 θ H + + HO2^-

H2O2 + OH^- θ HO2^- + H2O OH^- + HO2^- θ O2^2- + H2O O2^2- + H2O2> O2^- + OH^- + OH * OH * + H2O2> H2O [0135] Table 2 below shows typical properties of the acid solution formed on the anode and the basic solution formed on the cathode. The acid solution forms the concentrate stream and the basic solution forms the diluate stream.

- 24 Table 2 pH FAC (ppm) ORP (mV)

Acid solution (on the anode) 2 + 3.5 400 + 800 1100 + 1200

Basic solution (at cathode) 11 + 12.5 - 800 + 900 [0136] Two separate streams are mixed in a ratio to provide the product from the electrodializer and possibly a residue with the typical properties shown in Table 3. Table 3 pH FAC (ppm) ORP (mV )

Concentrate 7.5 + 8.5 500 + 800 750 + 800

Residue 11 + 12.5 800 + 900 [0137] Cross-processing can be used to match the chemical characteristics of both streams. This can be a system that allows part or all of one or both of the streams to be re-injected into the chamber opposite to the chamber from which the stream originates. Thus, the concentrate stream produced by the anode could be cross-treated by injection on the cathode side of the electrode. The stream / stream parameters expressed as pH, ORP and FAC can thus be adjusted to a greater extent and allow reduced diluate remaining after mixing if mixing is also used.

[0138] Recirculation of the respective streams from the respective chambers can also be used to match the characteristics of the two streams to improve the desired characteristics of the final product after mixing, as well as to reduce the amount of diluate remaining.

[0139] The mixing ratio will depend on the "quality" of the raw electrolyte, the size of the electrodes and the energy used.

[0140] The product 17 from the electrodializer 8 is introduced into the main stream after cavitation treatment. Nitrogen injection may occur before or after addition of product 17.

[0141] The ratio between concentrate / residue and ballast water flowing through the line is controlled by monitoring the ORP and FAC from the inflow side at the monitoring station 15. The characteristics and amounts of concentrate and diluate injected back into the main stream are controlled by monitoring the redox potential (ORP) and / or consumption of available free chlorine (FAC). The range of the desired ORP values ​​can be 300 + 500 mV. Instantaneous initial FAC values ​​after re-injection are preferably between 2 and 4 ppm and drop to 0.1 + 0.4 ppm after one hour.

[0142] Figure 19 shows an embodiment of an electrodializer 8 that can be used to treat water in the system of Figure 1A. Water is passed through the annular channel formed between the solid cylindrical anode 47 and the hollow cylindrical cathode 48. To form the electrodializer 8, an ion exchange membrane or ion selective membrane 49 is placed between the anode 47 and cathode 48. A cathode 48 and a membrane 49 are shown in partial section perspective. When the incoming electrolyte water flows through the annular channel, an acid concentrate 12 is formed on the anode side of the membrane 49, and an alkaline diluate solution is formed on the cathodic membrane 49. Part of the diluate stream 11 can be separated, and all or the rest of the diluate stream 11 is mixed with the stream concentrate 12 to produce a product from the electrodializer 17 as described above.

[0143] An alternative embodiment of the electrodeizer 8 to be embedded in the line is shown in Figure 20. The electrodializer 8 comprises a plate-shaped anode 47 and a plate-shaped cathode 48 on both sides of the membrane 49. The electrodializer 8 is placed in a tube 50 shown in partial perspective view, and the pipe 50 carries the entire water stream in the direction of the arrows. Most of the water will flow on one side of electrode 8, and only part of the water will flow into electrode 8 and flow between anode 47 and membrane 49 or between cathode 48 and membrane 49. When electric current flows through the electrodes, reactions will occur on the anode and cathode side. resulting in the diluate stream 11 and concentrate stream 12 on the cathode side and on the anode side, respectively, as described above.

[0144] To control the composition of the product from the electrodializer 17, recycled to the main water stream, a diluate discharge channel 51 is provided. The amount of diluate discharged from the electrodializer 8 is controlled based on ORP and / or FAC values ​​measured after the electrodializer 8. As described previously , in some cases the entire diluate will be mixed with the concentrate stream 12, so that no diluate will be removed. The concentrate stream 12 and the rest or all of the diluate stream 11 are then returned to the main water stream at the end of the electrodialyzer 8. These two parts together form the product from the electrodialyzer 17, although they are not mixed together until mixed with the main stream water when the flow through and around the electrode 8 reaches the end of the electrode 8.

[0145] In order to enable effective treatment, a number of electrodializers 8 may be placed in the system by the electrodialysis device at higher flow rates to treat water in parallel. Although the size of the electrodialyzer 8 can be increased to achieve the same effect, the construction of larger electrodializers becomes more complicated, so numerous smaller electrodializers are preferred. In addition, the use of smaller electrodializers allows for a more modular design, which means that the same parts can be mass-produced and combined to form systems for different flow rates of ballast water or other treated water.