WO1994002422A1

WO1994002422A1 - A method and apparatus for modifying water or a water-containing liquid substance

Info

Publication number: WO1994002422A1
Application number: PCT/DK1993/000242
Authority: WO
Inventors: Vagn Gundersen
Original assignee: Forskningscenter Risø
Priority date: 1992-07-27
Filing date: 1993-07-16
Publication date: 1994-02-03
Also published as: DK96392D0

Abstract

A method of modifying water or a water-containing liquid substance containing dissolved calcium carbonate and possibly also other chemical substances or materials which are dissolved, dispersed, and/or emulsified in the water-containing liquid substance, said method comprising exposing the water or the water-containing liquid substance to electromagnetic radiation so as to transmit electromagnetic energy to the water in an amount sufficient to cause a reduction in the amount of calcium carbonate which the water or water-containing liquid substance will deposit on the walls of tubes, conduits, and containers with which the water or the water-containing liquid substance comes in contact, and then supplying the water or water-containing liquid substance for a use where the modification is utilized. The water is preferably exposed to electromagnetic waves in the microwave region, with the amount of electromagnetic energy transferred to the water being insufficient to cause a major increase in temperature of the water but being sufficient to avoid incrustation. The invention also relates to an apparatus for modifying the water or the water-containing liquid, said apparatus comprising conduit means (10) for passing a flow of the liquid therethrough and defining a processing zone (11) therein, an electromagnetic wave generator (12) for exposing the liquid, and control means (14, 15) for controlling the operation of the electromagnetic wave generator (12) and/or the flow of liquid through the conduit means (10).

Description

A METHOD AND APPARATUS FOR MODIFYING WATER OR A WATER-CON¬ TAINING LIQUID SUBSTANCE

The present invention relates to a method of modifying water or a water-containing liquid substance containing dissolved calcium carbonate and possibly also other chemical substances or materials which are dissolved, dispersed, and/or emul¬ sified in the water-containing liquid substance. Normal tap water is often almost saturated or supersaturated with calcium carbonate. Because the solubility of calcium carbonate in water decreases with increasing temperature, calcium carbonate tends to precipitate on heating surfaces of any kind so as to form scaling or incrustation, which coun¬ teracts good heat transmitting conditions. Calcium carbonate may also precipitate on the walls of tubes or conduits through which water or a water containing liquid substance is flowing, especially where pressurized cold or hot water is exposed to a pressure relief, for example through nozzles, valves, or taps. This means that scaling or incrustation is a major problem in water supply conduits, containers and other technical equipment used in connection with supply of cold or hot water as well as in boilers and other water heating devices.

In the present specification and claims, the term "dissolved calcium carbonate" designates that the water (or water-con- taining liquid substance) in question contains calcium ions Ca⁺⁺ together with one or more of the species carbonate ions C0₃ ^""' hydrogen carbonate ions HC0₃ ^"' carbon dioxide C0₂, carbonic acid H₂C0₃ and calcium hydrogen carbonate ions CaHC0₃ ⁺. As is well known, the ions mentioned above may be present in water in various hydrated forms; the above listing is intended to cover both the unhydrated form and the ap¬ plicable hydrated forms. Depending on the conditions prevail¬ ing in the water, the various carbon- and oxygen-containing species will contribute to the product [Ca⁺⁺] [C0₃ ^"_:! , the value of which will determine whether the water is sub- saturated, saturated or supersaturated with calcium carbonate at the temperature in question.

According to the invention, it has been found that by means of electromagnetic radiation, it is possible to modify water or water-containing liquid substances containing dissolved calcium carbonate so that the dissolved calcium carbonate will either not precipitate to any substantial visible extent or will precipitate in a microscopic or sub icroscopic form in the bulk of the water instead of depositing on the inner surface of the conduits and containers with which the water or water-containing liquid substance comes in contact.

Thus, the present invention provides a method of modifying water or a water-containing liquid substance containing dissolved calcium carbonate, said method comprising exposing the water or the water-containing liquid substance to elec¬ tromagnetic radiation so as to transmit electromagnetic energy to the water in an amount sufficient to cause a reduc¬ tion in the amount of calcium carbonate which the water or water-containing liquid substance will deposit on the walls of tubes, conduits, and containers with which the water or the water-containing liquid substance comes in contact.

In the present specification and claims, the term "water- containing liquid substance" designates a water-containing product which more or less has the same viscosity as water, and which normally contains a high or very high amount of water, such as, e.g., 90% by weight or higher, such as 95% or higher. Water-containing liquid substances of particular interest in connection with the present invention are ingestible water-containing liquid substances, such as drinks and beverages, including beer and wine and pre-products and intermediate liquids in the production of beer and wine, fruit juices, soft drinks, either carbonated, liquid food¬ stuffs or feeds containing water, etc. Other water-containing liquid substances which it may be relevant to modify by the method of the invention are salt water, industrial waste waters, sewage, etc.

In the following, dissolved calcium carbonate which will deposit on the walls of tubes, conduits, and containers with which the water containing the dissolved calcium carbonate is contacted is termed "surface-depositable calcium carbonate".

The water modified by the electromagnetic radiation as described above may be used as feed water to be heated in a downstream or later heating process, typically at heating surfaces, e.g. to boilers, water heaters, evaporators or heat exchangers, where the modification results in a reduction or avoidance of deposition of calcium carbonate on the heating surfaces. The heating surfaces will normally be hot surfaces at which the water is heated by heat transfer through the heating surface, the heating surface itself being heated from the side which is not in contact with the water, e.g., by means of hot flue gas, by means of an electric resistance heater, by solar energy, either through direct solar radia- tion or via a fluid of high heat capacity, etc. As will be explained below, the water or water-containing liquid sub¬ stance modified by the treatment according to the invention may also be used as or in food or drink products or, in the case of water, for watering plants.

According to the invention, it has been found that a very substantial modification of water containing dissolved cal¬ cium carbonate will be obtained already by supplying, to the water, electromagnetic energy in an amount which will be insufficient to cause a major increase in temperature of the water, and such treatments in which the electromagnetic energy is supplied to the water or water-containing liquid substance to an extent sufficient to cause a reduction in the amount of calcium carbonate which the water or water-contain¬ ing liquid substance will deposit on the walls of tubes, con- duits, and containers with which the water or the water- containing liquid substance comes in contact, but in- sufficient to cause any major increase in the temperature of the water constitute important aspects of the present inven¬ tion.

Although it is not intended to limit the present invention to any particular theory, it is believed that the above described reduction of the amount of surface-depositable calcium carbonate in the water or the water-containing liquid substance modified in accordance with the present invention is due too an increase in the amount of so called "calcium carbonate nuclei".

In the present context, the term "calcium carbonate nuclei" means a submicroscopic amorphous or crystalline agglomerate comprising calcium carbonate CaC0₃. It is believed that calcium carbonate nuclei are formed when electromagnetic energy is transmitted to water or water-containing liquid substance containing calcium hydrogen carbonate ions CaHC0₃ ⁺ whereby the calcium hydrogen carbonate ions will dissociate into calcium carbonate molecules CaC0₃ and hydrogen ions H⁺ and the calcium carbonate will form the agglomerate. Alterna- tively, it is believed that calcium carbonate nuclei also can be formed around any charged submicroscopic particles in the water or the water-containing liquid substance. The trans¬ mission of electromagnetic energy to the water or the water- containing liquid substance is believed to cause disturbance of a "layer" of water molecules surrounding the micro par¬ ticles and the ions attracted thereto, thereby providing a possibility for the carbonate ions to associate with the calcium ions on the submicroscopic particles and thus to form a calcium carbonate nucleus.

It is an interesting possibility that the calcium carbonate nuclei generated by the method of the invention are nuclei which give rise to the formation of calcium carbonate in the crystal form which is termed aragonite and that this crystal form, once initiated in the nuclei, would be the crystal form in which calcium carbonate precipitates in the water or the water-containing liquid in question. If this is true, the aragonite crystal seeds may be crystal seeds which are advan¬ tageous with respect to a preferential submicroscopic "de¬ position" of calcium carbonate in the bulk as opposed to deposition on heating surfaces, tubes, etc.

In accordance with the above discussion, it is believed that the decrease in the amount of surface-depositable calcium carbonate is due to an increase in the number of calcium carbonate nuclei which has the effect that when dissolved calcium carbonate in the water or the water-containing liquid substance tends to precipitate, for example due to supersa- turation, turbulent flow, pressure relief, and/or heating of the water or the water-containing liquid substance, such precipitation takes place to a large extent in a sub- microscopic form on the calcium carbonate nuclei which are suspended in the water or the water-containing liquid sub¬ stance. Thereby, scaling and incrustation on tube and chamber walls and on heating surfaces may be substantially reduced. It is even believed that the modification of the water ac- cording to the invention may have the effect that scaling and incrustation previously formed may be partly or totally dissolved, while calcium carbonate is submicroscopically precipitated on the nuclei to maintain a state of equili¬ brium, or carbon dioxide liberated in the modifier "ion of the water may contribute to such dissolution.

It is believed that the time elapsed after the modification has a certain influence on the amount of surface-depositable calcium in the treated water, the amount being the smaller, the shorter the time elapsed after the treatment. Thus, in cases where the process of the invention is used for treating water which is to be passed to boilers or other heating surfaces, it is believed to be advantageous that the water is passed immediately from the treatment to the heating sur¬ faces, or expressed in another manner, that the method accor- ding to the invention is performed immediately upstream of the heating surfaces. The exposure of the water or the water-containing liquid substance to the electromagnetic radiation in the method of the invention may be performed in a processing zone wherein a portion of the water or^the water-containing liquid substance to be treated is contained and is processed as a batch, or the exposure may be performed in a processing zone wherein the water or the water-containing liquid substance is flowing continuously or intermittently. In the following, the inven¬ tion is explained in greater detail in connection with the latter embodiment, but it should be understood that the batchwise treatment may be a suitable alternative for a number of purposes.

It should be understood that the submicroscopic precipitation of dissolved calcium carbonate on calcium carbonate nuclei need not necessarily take place in the processing zone. Such precipitation may totally or partly take place at a later stage.

It has been reported that magnetic treatment of water has been found to improve the biological characteristics of water or water-containing liquid substance for watering plants or for human or animal consumption, see World Water/September 1989. It is presumed that a valuable and beneficial effect on the biological characteristics or utility of water is obtained when the water or the water-containing liquid sub- stance containing dissolved calcium carbonate is modified according to the present invention, and that this may be due to the formation of an increased amount of calcium carbonate nuclei, or, with respect to the presumed improvement in the biological characteristics of water used for watering plants or for human or animal consumption, that this is alternative¬ ly due to disturbance of the H₂0 layer around the ions in the water and disturbance of the clathrate structure formed by water molecules.

The process of the invention is considered as resulting in a reduction of the amount of surface-depositable calcium car- bonate in a sample as soon as there is a significant differ¬ ence in the deposition measured between the treated and the untreated water or water-containing liquid substance. A suitable way of expressing the effect is by referring to the ratio between the deposit in the untreated water or water- containing liquid sample and the deposit in the treated water or water-containing liquid substance. Normally, for the effect to be considered significant, there will be a ratio of at least 1.1, corresponding to a 10% decrease in the deposi- tion, but as will be seen from the example which follows, much higher effects can be expected, such as at least a ratio of 1.2, in many cases at least a ratio of 1.3 or 1.4 or higher, such as 1.5 or 1.7, and often a ratio of 2.0 or above, such as 2.5 or even higher.

As mentioned above, the microwave energy transmitted to the water or the water-containing liquid substance in order to cause a reduction in the amount of surface-depositable cal¬ cium carbonate may be relatively small so that no substantial or at least no major increase in temperature of the water or the water-containing liquid substance takes place. Thus, it has been found possible to obtain a drastic decrease in the amount of surface-depositable calcium carbonate in water by treatment with electromagnetic radiation in such an amount that the temperature increase of the water does not exceed about 1-2°C, see the example below. Thus, the modification and improvement obtained by the method of the invention is a surprising phenomenon which does not seem to be immediately dependent on the temperature increase of the water. In many embodiments of the method of the invention, the processing will be performed in such a manner that the temperature increase of the water or water-containing liquid substance is small, such as at the most 10°C, often at the most 5°C, such as at the most 2°C or at the most 1°C.

Thus, the method according to the present invention is clear- ly distinguished from the prior art disclosed in Canadian patent No. 1,169,925, and US patent Nos. 2,585,970, 2,978,562, 3,816,689, 4,310,738, and 4,358,652, which all relate to heating water by means of microwave energy in order to obtain hot water. The invention is also clearly distin¬ guished from the disclosure of German patent specification No. 3,419,722 which relates to the growth of crystals, specially single crystals in a solution which is exposed to microwave radiation.

As mentioned above, processing of the water or the water- containing liquid substance in accordance with the present invention need not involve a major increase in temperature of the water or the water-containing liquid substance. There¬ fore, if it is desired to produce hot water or steam or a hot water-containing liquid substance of any other kind, the water or water-containing liquid substance may, such as mentioned above, subsequently be heated by means of energy from an energy source different from the electromagnetic wave generator by means of which the method according to the invention is performed. As an example, fresh or salt water supplied to a conventional boiler, water heater, steam gene- rator, evaporator or concentrator may first be modified in accordance with the present invention. When the water or the water-containing liquid substance is later heated and, there¬ by, becomes saturated or supersaturated with calcium carbon¬ ate, the calcium carbonate will to a large extent precipitate submicroscopically in the bulk of the water, whereby forma¬ tion of scaling or incrustation on the heating surfaces of the heating apparatus in question may be substantially reduced.

The water or water-containing liquid substance being pro- cessed may, for example, be exposed to electromagnetic radi¬ ation while flowing through a conduit, which may then be a part or section of a supply conduit or discharge conduit for the liquid substance in question. The water or the water- containing liquid substance may then be exposed to electro- magnetic radiation while flowing continuously or intermit¬ tently through the conduit in question. The reduction in the amount of the surface-depositable cal¬ cium carbonate in the water or the water-containing liquid substance may be facilitated if turbulence is caused in the water or the water containing liquid substance while it is exposed to electromagnetic radiation. Such turbulence may be created in any suitable manner, for example by means of stationary flow obstacles arranged within and/or immediately prior to the processing zone, or by means of rotating or rotatable stirring means, and/or by coiling the tube through the water or water-containing liquid substance flows. The turbulent flow will preferably be a flow comparable to a flow having a Reynolds value greater than 3000, in particular greater than 10,000 or even higher, such as greater than 20,000 or greater than 40,000.

The method according to the present invention may be used in connection with the water or the water-containing liquid substance of any kind and may very advantageously be used for processing tap water, for example when it is flowing through a water supply conduit to a dwelling house, a factory or another tap water consuming installation.

When the water or the water-containing liquid substance to be processed is flowing through a conduit, all of the water or the water-containing liquid substance may be exposed to electromagnetic radiation while it is flowing through a certain section of the conduit or tube. However, it may be sufficient to process part of a water or a water-containing liquid substance flow to create the desired reduction in the amount of surface-depositable calcium carbonate. Therefore, the water or the water-containing liquid substance flowing through said conduit may be branched off from a main flow and reunited with such main flow after having been exposed to electromagnetic radiation.

In case the water or the water-containing liquid substance is to be heated by means of another energy source after the exposure to electromagnetic radiation, and/or when the water or the water-containing liquid substance being processed is branched off from a main flow so that only part of the water or the water containing liquid substance is processed, the electromagnetic wave intensity and/or exposure time is often increased. Thus, in such cases, but also in other cases wherever suitable, the electromagnetic radiation may be dosed in such a manner that considerable temperature increases in the water are effected. In this connection, it may be par¬ ticularly advantageous that the water is heated, by means of the electromagnetic radiation, to a temperature of about 55- 70, preferably about 60-65°C, because it is known that at this temperature, the calcium carbonate precipitation ten¬ dency is particularly pronounced, so that it is reasonable to presume that a particularly large amount of calcium carbonate nuclei will be formed. However, the temperature increase of the liquid substance due to the exposure to electromagnetic radiation may also in the above-mentioned special cases be of an order where it will not exceed 30°C, or will not exceed 20°C, or will not exceed 10°C.

It is presumed that it is advantageous for the modification aimed at that the starting temperature of the water or water- containing liquid substance subjected to the method of the invention is relatively low, such as tap water temperature, typically in the range of 5-10°C. The advantageous tempera- ture is presumed to depend on the supersaturation of the water or water-containing liquid substance.

When branching-off is used, the water or the water-containing liquid substance branched off may be returned to the main flow after processing according to the present invention. The processed water or water-containing liquid substance may be returned to the main flow downstream of the position where it is branched off. Alternatively, the processed liquid sub¬ stance may be returned to the main flow at or upstream of the position where it is branched off so that the branched off and processed water or water-containing liquid substance may at least partly be recirculated through said conduit for further processing.

The microwave energy transmitted to the water or the liquid substance in order to cause a reduction in the amount of surface-depositable calcium carbonate may be in the range from 0.01 to 40 Joule per gram of water or water containing liquid substance (calculated on the total amount of the water modified, which means that the water subjected to the elec¬ tromagnetic radiation is a branched-off part of a main flow, the energy supply should be calculated not only on the branched-off flow, but rather on the sum of the main flow and the branched-off flow) , normally in the range from 1 to 20 Joule per gram of water or water containing liquid substance, preferably in the range from 3 to 8 Joule per gram of water or water containing liquid substance or more preferably in the range from 4 to 6 Joule per gram of water or water con¬ taining liquid substance. However, as mentioned above, there may be cases where it is desired to achieve a heating effect, and even a considerable heating effect, such as a heating to 60-65°C, in connection with the processing according to the invention; such heating will, of course, mean that more energy must be supplied to the water.

The frequency of the electromagnetic radiation used in con¬ nection with the present invention may be chosen within rather wide limits. Thus, the frequency of the electromag¬ netic radiation is normally in the range 200-300,000 MHz, in the microwave region 300-300,000 MHz or in subranges of the microwave region such as 300-30,000 MHz, 300-3000 MHz, 1000- 3000 MHz, 2400-2500 MHz and preferably about 2450 MHz. The electromagnetic radiation may have a frequency which in which one or more of the species Ca⁺⁺, C0₃ ^~~' HC0₃ ^"' C0₂, CaHC0₃ ⁺, H₂C0₃, and H₂0 in the water or the water containing liquid substance absorbs or absorb.

The electromagnetic energy may preferably be transmitted to the water or the water containing liquid substance so that the electromagnetic energy is substantially continuously transmitted to the water or the water-containing liquid sub¬ stance when the electromagnetic wave generator is activated.

The processed water or water-containing liquid substance may in some cases be used for animal or human consumption. Thus, modified tap water and modified water or water-containing liquid substance of other kinds may be used as drinking water or beverages, and nutritious water-containing liquid substan¬ ces may be used as human food or animal feed. It is believed that the biological characteristics of such modified liquid substances are improved, which means that plant or animal or human development and growth is improved when, in connection with water used by the plants or water ingested by the ani¬ mals or humans, water which is not treated according to the invention is replaced with water which is treated according to the invention.

Because of the improved biological characteristics, modified water may also advantageously be used for watering plants. Such modified water may, for example, contain artificial and natural fertilizers. As an example, sewage water having been processed in accordance with the method of the present inven¬ tion or possible other treatments may advantageously be used as fertilizer.

According to another aspect, the present invention provides an apparatus for processing water or a water-containing liquid substance containing dissolved calcium carbonate, said apparatus comprising conduit means for passing a flow of the water or the water-containing liquid substance therethrough and defining a processing zone therein, an electromagnetic wave generator for exposing the water or the water-containing liquid substance in said processing zone to electromagnetic radiation so as to transmit electro¬ magnetic energy thereto, and control means for controlling the operation of the elec¬ tromagnetic wave generator and/or the flow of water or water- containing liquid substance through the conduit means so as to transmit electromagnetic energy to the water or the water- containing liquid substance in an amount to cause a reduction in the amount of surface-depositable calcium carbonate but insufficient to cause a major increase in temperature of the ^' liquid substance, insufficient to heat the water or the water-containing liquid substance to a temperature above about 60-65°C.

The conduit means may comprise a tube section defining the processing zone and being adapted to be inserted in a water or a water-containing liquid substance supply conduit, and the control means may then comprise a flow detector for detecting water or water-containing liquid substance flow in the supply conduit and switch means for activating the elec¬ tromagnetic wave generator when a water or a water-containing liquid substance flow is detected by the flow detector and for activating the electromagnetic wave generator when a liquid flow is detected by the flow detector and for inac¬ tivating the electromagnetic wave generator when no such flow is detected. The tube section may, for example, be inserted in a water supply line, from which water is withdrawn when needed. The electromagnetic wave generator will then function only when water is withdrawn from the conduit. Alternatively, the conduit means may comprise a processing chamber defining said processing zone therein, and the processing chamber may have water or water-containing liquid substance inlet and outlet valves. The control means may then be adapted to control the function of the valves and the function of the electromagnetic wave generator so as to cause water or water- containing liquid substance to flow intermittently with a dwelling time in the processing chamber where it is exposed to electromagnetic radiation.

The invention also relates to a water or a water-containing liquid substance which contains dissolved calcium carbonate and which has been modified in accordance with the methods described above.

The invention will now be further described with reference to the drawings, diagrammatically showing various embodiments of the apparatus according to the invention.

In the drawings

Fig. 1 illustrates an embodiment of the apparatus according to the invention mounted in a water or a water-containing liquid substance supply conduit for processing the water or the water-containing liquid substance flowing therethrough, Fig. 2 illustrates an embodiment of the apparatus according to the invention mounted in a branch conduit or bypass con¬ duits of a water supply tube, Fig. 3 illustrates a system corresponding to that shown in Fig. 2, where at least part of the water processed in the apparatus according to the invention may be recirculated through the apparatus,

Fig. 4 illustrates a modified system corresponding to that shown in Fig. 2, Fig. 5 illustrates a modified system corresponding to that shown in Fig. 3,

Fig. 6 illustrates a system, which has been used for experi¬ ments, Fig. 7 is an axial sectional view of a conduit section de- fining a processing chamber, where the microwave generator is arranged within the conduit section,

Fig. 8 is an axial sectional view of a conduit section de¬ fining a processing chamber having turbulence creating means arranged therein, and Fig. 9 is a container shaped processing chamber having a microwave generator arranged therein and being connected to inlet and outlet conduits.

Fig. 1 shows a supply conduit or supply tube 10 for water, such as tap water, or another water-containing liquid sub- stance. The conduit 10 comprises a conduit section or tube section 11 made from glass, plastic material (for example teflon or polyethylene) , ceramics or another material allow¬ ing electromagnetic radiation to pass. A electromagnetic wave source such as a microwave source or a electromagnetic gene- rator such as a microwave generator 12 and the tube section 11 are enclosed within a metal casing or housing 13. A con¬ trol unit 14 comprising a flow sensor 15 controls the opera¬ tion of the microwave generator 12 in dependency of the liquid flow through the supply tube 10 to a consumer 16, which may, for example, be a dwelling house, a factory, a boiler, an evaporator, a heat exchanger, etc.

A water or a water-containing liquid substance flow through a conduit 10 to the consumer 16 is detected by the flow sensor or flow detector 15. When a flow signal is received by the control unit 14 from the flow detector 15, the microwave generator 12 is operated. This means that water or water- containing liquid substance flowing through the processing zone within the casing or housing 13 via the tube section 11 is exposed to microwaves from the generator 12. In accordance with what is mentioned above, it is presumed that the effect obtained through the modification according to the invention can be explained as follows:

The exposure to the microwaves from the generator 12 results in the formation of a large number of calcium carbonate nuclei in the flowing liquid, and/or results in disturbance of the clathrate structure of the water. If the water or the water-containing liquid substance is saturated or super¬ s'*:urated with calcium carbonate, the calcium carbonate will t ;ιd to precipitate on the free nuclei in the water or the water-containing liquid substance rather than on the inner walls of the supply tube 10 downstream of the tube section 11. The nuclei, thus formed, will remain in the water or the water-containing liquid substance supplied to the consumer 16. If for some reason (for example heating or pressure relief) calcium carbonate is caused to precipitate at the consumer 16, such precipitation will to a great extent take place on the free nuclei contained in the water or the water- containing liquid substance and thus increase the amount of depositable of calcium carbonate therein, whereby the forma¬ tion of scaling and incrustation on heating surfaces and other inner surfaces coming into contact with the water or the water-containing liquid substance at the consumer 16 may be substantially reduced.

Whenever surface-deposition of calcium carbonate is mentioned herein, this is intended to include also other scales or deposits which are formed together with calcium carbonate deposits. Thus, dependent on the chemical composition of the water, magnesium carbonate and other salts may deposit together with the calcium carbonate deposit. Normally, how¬ ever, calcium carbonate constitutes by far the largest amount of a scale or deposition and will be the dominating factor in whether a scale is formed or not. The effect of the modifica¬ tion according to the invention is believed to be relatively unaffected by the presence of even rather high amounts of other depositable ions, possibly due to the obtainment of similar phenomena for such other ions by the method of the invention.

In the system shown in Fig. 2, the casing or housing 13 containing the microwave generator 12 and the conduit or tube section 11 is arranged in a branch conduit or a bypass con- duit 17 which is connected to the main conduit 10 through valves 18 and 19 arranged mutually spaced along the main conduit 10. The flow detector 15 is positioned in the main conduit between the valves 18 and 19, and the control unit 14 is not only controlling the operation of the microwave gene- rator, but also the operation of a pump 20 arranged in the branch conduit 17 downstream of the conduit section 11. Alternatively, the pump 20 could be arranged upstream of the conduit section 11.

' When water or water-containing liquid substance is flowing through the supply tube 10, the control unit 14 receives a flow signal from the flow sensor 15 and operates the micro¬ wave generator 12 and the pump 20 whereby part of the water or the water-containing liquid substance is passed through the branch conduit 17 and the tube section 11. The water or the water-containing liquid substance passing through the branch conduit 17 is exposed to microwaves whereby a great number of calcium carbonate nuclei are formed in the liquid, which is reunited with the main flow at the valve 19. When no water or water-containing liquid substance flow is detected in the supply tube 10, the operation of the microwave gene¬ rator 12 and the pump 20 are stopped. The proportion of water or water-containing liquid substance passed through the branch conduit 17 may be adjusted by adjusting the valves 18 and 19.

In the system shown in Fig. 3, the branch conduit 17 com¬ prises two parallel conduit parts 21 and 22, the ends of which are interconnected by adjustable valves 23 and 24 forming part of the branch conduit 17. The tube section 11, which is arranged within the metal casing or housing 13, forms part of the conduit part 22, and a recirculating pump 25 is included in the conduit part 21.

During operation, the control unit 14 controls the function of the pumps 20 and 25 and of the microwave generator 12 in response to signals from the flow sensor 15 in the supply conduit 10. If desired, the control unit 14 may also control the valves 23 and 24.

Thus, in the system shown in Fig. 3, part of the water or the water-containing liquid substance flowing in the supply tube 10 is diverted from the supply tube and passed through the branch conduit 17 and through the processing zone thereof.

By properly controlling the pumps 20 and 25 and possibly also the valves 23 and 24, part of the processed water or water- containing liquid substance flowing from the tube section 11 may be recirculated through the conduit part 21 and through the processing zone. The water or the water-containing liquid substance having been processed one or more times is moved back into the main flow in the supply line 10 through the valve 19.

Fig. 4 illustrates a system corresponding to the system shown in Fig. 2, the only difference being that in Fig. 4, liquid is being circulated through the branch conduit 17 in a direc¬ tion opposite to that of Fig. 2. Thus, in Fig. 4, water or water-containing substance liquid is diverted from the main flow in the supply conduit 10 at the valve 19, and the pro¬ cessed water or water-containing liquid substance having passed the tube section 11 within the housing 13 is returned to the main flow in the supply conduit 10 at the valve 18, i.e. at a position upstream of the position where the liquid was diverted. Because the water or the water-containing liquid substance flowing in the supply line 10 between the valves 18 and 19 is a mixture of processed and non-processed water or water-containing liquid substance, this is also true for the water or the water-containing liquid substance being branched off at the valve 19 and passed to the processing zone through the branch conduit 17.

The system illustrated in Fig. 5 differs from that shown in Fig. 3 only by the fact that in Fig. 5, the pumps 20 and 25 are pumping the water or the water-containing liquid sub- stance in directions which are opposite to the directions in which these pumps are pumping the water or the water-contain¬ ing liquid substance in Fig. 3. As illustrated by arrows in Fig. 5, liquid is diverted from the supply conduit 10 at the valve 19, and processed water or water-containing liquid substance is returned to the supply conduit at the valve 18, i.e. upstream of the position where the water or the water- containing liquid substance was diverted. Furthermore, at least part of the water or the water-containing liquid sub¬ stance having been processed in the housing 13 may be recirculated to the tube section 11 for further processing via the conduit part 21. Fig. 6 illustrates an arrangement which has been used for the experiments of the example below. Tap water from a supply line 26 is passed through a spiral or coiled tube 27 having a length of 8 meter and an inner diameter of 8 mm. The tube, which is made from teflon and comprises 21 turns of windings is arranged within a conventional microwave oven 28 of the type Phillips AVM764. The spiral tube 27 is connected to a T- connector 29 and a diverting tube 30 by means of a connecting tube 31 having a length of 3 meters, an inner diameter of 10 mm, and being made from polyvinyl chloride. The non-diverted tap water is passed to waste through a discharge conduit 32. Tap water is also discharged from the supply conduit 26 upstream of the microwave oven 28, through a diverting tube 33 connected to the supply line 26 by means of T-connector 34. The spiral tube 27 is connected to the T-connector 34 by. means of a connecting tube 48 having a length of 1 meter, an inner diameter of 10 mm, and being made from polyvinyl chlor¬ ide. The diverting tubes 30 and 33 are identical, having a length of 1 meter and an inner diameter of 5 mm, and are made from polyvinyl chloride. The liquid flowing through the first of the diverting tubes 33 is passed through a first flow meter 35, a first connecting tube 47 and subsequently through a first measuring cell 36, and the liquid flowing through the second of the diverting tubes 30 is passed through a second flow meter 35, a second connecting tube 47, and subsequently through a second of measuring cells 36. The measuring cells 36 are identical. Each of the identical connecting tubes 47 have a length of 15 cm and an inner diameter of 5 mm, and are made from polyvinyl chloride. The measuring cells 36 include identical electric heaters 37 arranged therein, each electr¬ ical heater 37 having a tubular body with an outer diameter of 8 mm and being made from stainless steel. Each of the heaters 37 defines a heating surface 38 which is in contact with the water in the measuring cell 36, the area of the heating surface 38 being 12 cm². Each of the measuring cells also contains a thermometer 39 for measuring the temperature of the water leaving the cell through an outlet 40. Each of the identical measuring cells 36 are substantially U-shaped and made from glass, and the heater 37 and the thermometer 39 are received in tubular parts having a diameter of 18 mm and 12 mm, respectively. The height from the bottom of the cell to the outlet 40 is 10 cm.

In the embodiments shown in Figs. 1-6 and described above, the microwave generator 12 is arranged outside the tube section 11, which is made from a material allowing microwaves to pass therethrough. Alternatively, the microwave generator 12 could be connected to a microwave emitting source such as an antenna 46 arranged within the tube section 11 defining the processing zone as shown in Fig. 7 or the microwave generator itself could alternatively be arranged within the tube section 11 defining the processing zone. In that case the tube section 11 may be made from metal, and the metal casing or housing 13 may then be dispensed with. In further alternative embodiments not shown in the drawings, the tube sections in Figs. 1-6 are made from metal but having section parts of material allowing the microwaves to pass there¬ through, and the microwave generators are arranged outside these tube section parts. Alternatively, the tube could be provided with a number of such section parts, preferably placed on opposite sides of the tube section each having a microwave generator emitting microwaves so as to generate a cross field of microwave inside the tubes.

The tube section 11 may advantageously be provided with turbulence creating means 41, which may, for example, be projections formed on the inner surface of the tube section 11 as shown in Fig. 8. While the tube section 11 is illu¬ strated as a rectilinear tube section in Figs. 1-5, 7 and 8, this tube section may alternatively have any suitable curved shape, such as a spiral shape.

As described above in connection with Figs. 1-5, the water or the water-containing liquid substance may be exposed to the microwaves generated by the microwave generator 12 while the water or the water-containing liquid substance is flowing through a tube section 11. However, the systems illustrated may also be operated so that the water or the water-contain¬ ing liquid substance is exposed to microwaves while it is in rest. In that case, the control unit may control the opera- tion of the valves 18, 19, 23, and 24 and of the pumps 20 and 25 so that the liquid has a certain dwelling time within the tube section 11, whereafter the processed water or water- containing liquid substance in the tube section may be replaced by non-processed water or water-containing liquid substance so that water or water-containing liquid substance is moved intermittently through the tube section 11.

In Fig. 9, the microwave generator 12 is arranged within a processing container 42 which may be made from metal. Water or water-containing liquid substance to be processed is passed into the processing container 42 through an inlet tube 43, and processed liquid may leave the container 42 through an overflow or an outlet tube 44. The water or the water- containing liquid substance space of the container 42 may be separated from the microwave generator 12 by a partition wall or partition plate 45 made from glass, plastic material or another material allowing microwaves to pass. The water or the water-containing liquid substance to be processed may flow continuously through the container 42, or water or water-containing liquid substance may be supplied intermit- tently through the inlet tube 43 so that processed water or water-containing liquid substance is displaced and removed from the container 42 by non-processed water or water-con¬ taining liquid substance flowing through the inlet tube 43.

The reduction in the amount of surface-depositable calcium carbonate contained in water or water-containing liquid sub¬ stance modified in accordance with the method of this inven¬ tion can be tested by comparing the surface-depositable amount of calcium carbonate in the modified water or water- containing liquid substance with the amount in the non-modi- fied water or water-containing liquid substance. Such a test is described in the following. In the test, a fixed amount of the modified water or water- containing liquid substance and an identical amount of the non-modified water or water-containing liquid substance are used.

Before testing the water or the water-containing liquid substance, the concentration of calcium ions and the con¬ centration of carbonate ions are determined to make sure that the reduction in the amount of surface-depositable calcium carbonate is due to the processing of the water or water- containing liquid substance and not to a change in the amount of calcium carbonate therein.

The concentration of calcium ions can be determined in a well-known manner e.g. by atomic absorption spectrophotometry or by titration. The concentration of carbonate ions can be determined by titration or on the basis of measurement of pH and titration of HC0₃ ^"' considering that the carbonate ions in the water will form the following equilibrium with the water molecules:

C0₃ ^"" + H⁺ «•» HC0₃ ^"-

The fixed amount of processed and the identical amount of non-processed water or water-containing liquid substance are led through two identical measuring cells, e.g. of the type illustrated in Fig. 6.

The two electrical heaters are weighed in dry condition before the water or the water-containing liquid substance is led through the measuring cells. The measuring cells are provided with thermometers 39 for monitoring the temperature during the process.

Then the processed and the non-processed water or water- containing liquid substance are led through the identical measuring cells in order to precipitate calcium carbonate on the heating surfaces of the electric heaters. When using measuring cells as illustrated in Fig. 6, the water or the water-containing liquid substance is passed through the first flow meter 35, the first connecting tube 47, and the measuring cell 36 with a flow of about 45 ml/min controlled by flow meters, which is adjusted so that the temperature of the water flowing in the measuring cell 36 is substantially the same within the two tubular parts of each cell, which again, due to the identity of the two measuring cells and their parameters, also means that the flow in the two cells is substantially the same.

It will be understood that while Fig. 6 shows a configuration where the processing unit is arranged between the T-con¬ nectors 34 and 29, the two identical measuring cells 36 can also be used for water samples which have been processed elsewhere and are delivered to the testing in, e.g., bottles or tanks.

When the measuring cells are filled with water or water- containing liquid substance the heaters are activated. The heaters are deactivated when the fixed amounts of water or water-containing liquid substance have passed through their respective cells.

The electrical power given off from the heating surface of each of the heating cells 37 illustrated in Fig. 6 is 12.5 watt/cm², and the total power given off from the electric heater 37 is 150 watt.

After the water or the water-containing liquid substance has been led through the measuring cells, the heaters are dipped in 96% ethanol, whereafter they are dried and weighed. The weight increase is a measure of the precipitation of calcium carbonate, and the difference in weight between the heater from the measuring cell wherein the non-processed water or water-containing liquid substance has been led and the heater from the measuring cell wherein the processed water has been led is thus a measure of the reduction in the amount of surface-depositable calcium carbonate contained in the pro¬ cessed water or water-containing liquid substance.

A measure of this reduction can be expressed by the ratio F/E, where F is the amount of material precipitated on the electrical heater in the measuring cell through which the non-processed water or water-containing liquid substance has been led and E is the amount of material precipitated on the electrical heater in the measuring cell through which the processed water or water-containing liquid substance has been led.

The reduction in the amount of surface-depositable calcium carbonate can, of course, be determined by atom absorption spectrophotometry. After the heaters have been weighed, the heating surfaces of the heaters are cleaned in solutions of 20% acetic acid and the calcium content in each solution is determined by atom absorption spectrophotometry. The dif¬ ference in the calcium content in the two solutions is com¬ pared and used as a measure of the difference in precipita¬ tion of calcium carbonate and thus as a measure of the reduc- tion in the amount of surface-depositable calcium carbonate contained in the processed water. A measure of this reduction is given by the ratio of the calcium content H in the first solution to the calcium content G in the second solution as expressed by H/G.

According to the present invention, either of the two tests described above, including the construction, dimensions and data of the measuring cells, qualifies as a definition of "the test described herein", as referred to above and in the claims, provided that the amount of processed and unprocessed water, respectively, flowing through each cell of the dimen¬ sions and capacities defined above is at least 1.5 liters, preferably at least 3.0 liters.

As mentioned above, the test strategy described above, in¬ cluding the test equipment described, can be used for the a- ssessment of the influence of the modification according to the invention on surface-depositable calcium carbonate in the water. Because of the comparison between non-processed water or water-containing liquid substance and processed water or water-containing liquid substance, sources of error which would otherwise be introduced by components which are not as¬ sociated with the calcium carbonate will tend to be compen¬ sated for.

Thus, whenever the present specification and claims make reference to "the test described herein", the test described above is the one referred to, including the particular data of the test equipment. On the other hand, it is evident that similar test strategies could be made with variation of a number of the parameters, and such tests would, of course, also be useful as long as the involve a deposition system by means of which calcium carbonate which tends to deposit on heated surfaces can be accurately determined and reliable compared between water or water-containing liquid substance treated in accordance with the present invention and cor- responding water or water-containing liquid substance which is not treated. It is believed that the kind of equipment described above in "the test described herein", i.e. equip¬ ment where the treated and untreated water, respectively, flow in a relatively narrow conduit along the heating surface will be the type of equipment most suitable for the test. On the other hand, it is believed that the accuracy of the test would be further improved by enlarging the heating surface and reducing the effect per square centimetre, e.g., from the about 12.5 Watt to about 2.5 Watt.

Thus, it is to be understood :hat a similar test can be carried out with the measuring cells illustrated in Fig. 6 in which the total power dissipated from the electrical heaters 37 has a value which differs from 150 watt and in which the flow of the water or the water-containing liquid substance into the measuring cells 36 has a value which may be dif¬ ferent from 45 ml/min. EXAMPLE

A number of experiments were performed using the test method described above, including an experimental arrangement as that shown in Fig. 6 and described in detail above with respect to its data and parameters.

An analysis of the water from the source used in the experi¬ ments is as follows:

Analysis

The various measuring methods referred to are as follows: DS: Danish Standard

S.M.: Standard Method (U.S.A.)

OIC 700: Apparatus used for measuring non-volatile organic carbon.

The temperature of the tap water immediately from the tap was about 8°C. The temperature of the water in the test cell upstream of the oven 28 was 11°C, and the temperature of the tap water in the test cell downstream of the oven was 12.5°C so that the microwave energy transmitted to the tap water flowing through the spiral tube 27 gave rise to a temperature increase of only 1.5°C.

Prior to each experiment, each of the two heaters were weig¬ hed in dry condition, see the following tables. During the experiment, calcium carbonate precipitated on the heating surfaces 38 of the electric heaters 37, and after each ex¬ periment, the heaters are dipped in 96% ethanol, whereafter they are dried and weighed, in accordance with the specifica¬ tion of "the test described herein".

Two series of experiments, A and B, were carried out. The heaters 37 were connected directly to the electrical power supply, which means that the supply voltage has varied to some extent during each experiments. Consequently, the tem¬ perature in the measuring cells has also varied during each single experiment. During all experiments in series A, the power of the microwave oven 28 was adjusted to 750 watt. However, due to an error, the oven was disconnected for shorter or longer periods during the experiment, whereby the microwave energy transmitted to the tap water was somewhat reduced and the efficiency was not optimum.

In the following tables, the efficiency of the processing of the water is expressed as a relationship between the amount of material F precipitated on the heating surface 38 of the electric heater 37 arranged upstream of the oven 28 where the water is non-processed, and the amount E precipitated on the heater 37 arranged downstream of the oven 28, where the water is processed. As mentioned above, this means that the effect of the processing of water is the better the more the value F/E exceeds l.

EXPERIMENTS A

Experiments Water tern- Diverted perature in flow

No. measuring ml/min. cells, °C

1 56-62 47 2 66-71 40 3 54-58 49 4 60-65 45

Average F/E = 3,3

In order to confirm that it is the microwaves to which the water is exposed during the experiment A which in¬ fluence on the results obtained, similar experiments, B, were made while the microwave oven 28 is turned off.

EXPERIMENTS B

Experiments Water tern- Diverted perature in flow measuring ml/min. cells, °C

5 62-67 44 6 63-64 45 7 63-65 45

Average F/E = 1,2 Thus, by comparing the results with the results from A, it was confirmed that the effect is due to the microwave treatment.

It should be noted that under more stringently con- trolled conditions, e.g. with respect to variations in the current supply, the variations in experiment B would have been much smaller, of the order of less than 10%.

Claims

1. A method of modifying water or a water-containing liquid substance containing dissolved calcium carbonate, comprising exposing the water or the water-containing liquid substance to electromagnetic radiation so as to transmit electromagnetic energy to the water in an amount sufficient to cause a reduction in the amount of calcium carbonate which the water or water-containing liquid substance will deposit on the walls of tubes, conduits, and containers with which the water or the water-containing liquid substance comes in contact, and then supplying the water or water-containing liquid substance for a use where the modification is utilized.

2. A method according to claim 1, wherein the water is conducted through tubing and valves.

3. A method according to claim 1, wherein the modified water is supplied to a boiler, a water heater, an eva¬ porator or a heat exchanger.

4. A method according to claim 1, wherein the modified water is used for human or animal consumption, or for watering plants.

5. A method according to any of the preceding claims, wherein the exposure of the water or the water-contain¬ ing liquid substance to the electromagnetic radiation is performed in a processing zone wherein the water or the water-containing liquid substance is flowing continuous¬ ly or intermittently.

6. A method according to any of the preceding claims, wherein the reduction in the amount of surface-deposit- able calcium carbonate corresponds to a ratio of at least 1.1 between surface deposit of calcium carbonate on a heated surface from non-modified water and water treated by the exposure to the electromagnetic radia¬ tion, e.g. as determined by the test described herein.

7. A method according to claim 6, wherein the reduction in the amount of surface-depositable calcium carbonate corresponds to a ratio of at least 1.2.

8. A method according to claim 6, wherein the reduction in the amount of surface-depositable calcium carbonate corresponds to a ratio of at least 1.3.

9. A method according to claim 6, wherein the reduction in the amount of surface-depositable calcium carbonate corresponds to a ratio of at least 1.4.

10. A method according to claim 6, wherein the reduction in the amount of surface-depositable calcium carbonate corresponds to a ratio of at least 1.5.

11. A method according to claim 6, wherein the reduction in the amount of surface-depositable calcium carbonate corresponds to a ratio of at least 1.7.

12. A method according to claim 6, wherein the reduction in the amount of surface-depositable calcium carbonate corresponds to a ratio of at least 2.0, preferably at least 2.5.

13. A method according to any of the preceding claims, wherein the electromagnetic energy to which the water or the water-containing liquid substance is exposed is insufficient to cause a major increase in temperature of the water or the water-containing liquid substance.

14. A method according to claim 13, wherein the tempera¬ ture increase does not exceed 10°C.

15. A method according to claim 13, wherein the tempera¬ ture increase does not exceed 5°C.

16. A method according to claim 13, wherein the tempera¬ ture increase does not exceed 2°C.

17. A method according to any of claims 1-12, wherein the temperature of the water or water-containing liquid substance is increased by more than 10°C by means of the electromagnetic radiation.

18. A method according to claim 17, wherein the tempera- ture of the water or water-containing liquid substance is increased to about 60-65°C by means of the electro¬ magnetic radiation.

19. A method according to any of the preceding claims, wherein the liquid substance is subsequently heated by means of energy from an energy source different from an electromagnetic wave generator.

20. A method according to any of the preceding claims, wherein the water or water-containing liquid substance is exposed to the electromagnetic radiation while flow- ing through a conduit.

21. A method according to any of the preceding claims, wherein the water or water-containing liquid substance is subjected to turbulent flow while it is exposed to the electromagnetic radiation.

22. A method according to any of the preceding claims, wherein the water modified is tap water.

23. A method according to claim 20 or 21, wherein the water or the water-containing liquid substance flowing through the conduit is branched off from a main flow and reunited with such main flow after having been exposed to the electromagnetic radiation.

24. A method according to claim 23, wherein the tempe¬ rature increase caused by the exposure of the branched- off flow to the electromagnetic radiation does not exceed 10°C.

25. A method according to claim 23 or 24, wherein the water or the water-containing liquid substance branched off is at least partly recirculated through said con- duit.

26. A method according to claim 1, wherein the electro¬ magnetic energy transmitted to the water or the water- containing liquid substance is in the range of 0,01-40 Joule per gram of water or water-containing liquid sub- stance.

27. A method according to claim 26, wherein the electro¬ magnetic energy transmitted is in the range of 1-20 Joule per gram of water or water-containing liquid sub¬ stance.

28. A method according to claim 26, wherein the electro¬ magnetic energy transmitted is in the range of 3-8 Joule per gram of water or water-containing liquid substance, preferably 4-6 Joule per gram of water or water-contain¬ ing liquid substance.

29. A method according to any of the preceding claims, wherein the waves of electromagnetic radiation has a frequency in the range from 200 to 300,000 MHz.

30. A method according to claim 29, wherein the waves of electromagnetic radiation have a frequency in the micro- wave region from 300 to 300,000 MHz.

31. A method according to claim 30, wherein the fre¬ quency is within the range from 300 to 30,000 MHz.

32. A method according to claim 31, wherein the fre¬ quency is within the range from 300 to 3000 MHz.

33. A method according to claim 32, wherein the fre¬ quency is within the range from 1000 to 3000 MHz.

34. A method according to claim 33, wherein the fre¬ quency is within the range from 2400 to 2500 MHz, pre¬ ferably about 2450 MHz.

35. A method according to claim 29, wherein the electro¬ magnetic waves have a frequency which is absorbed by one or more of Ca⁺⁺, C0₃ ^""' HC0₃ ^"' C0₂, CaHC0₃ ⁺, H₂C0₃ and H₂0 in the water or the water-containing liquid substance.

36. A method according to any of the claims 29-35, whe- rein the electromagnetic energy is substantially con¬ tinuously transmitted to the water or the water-contain¬ ing liquid substance when the electromagnetic wave gene¬ rator is activated.

37. An apparatus for modifying water or a water-contain- ing liquid substance containing dissolved calcium car¬ bonate, said apparatus comprising conduit means for passing a flow of the water or the water-containing liquid substance therethrough and de¬ fining a processing zone therein, a electromagnetic wave generator for exposing the water or the water-containing liquid substance in said processing zone to electromagnetic radiation so as to transmit electromagnetic energy thereto, and control means for controlling the operation of the electromagnetic wave generator and/or the flow of water or water-containing liquid substance through the conduit means so as to transmit electromagnetic energy to the water or the water-containing liquid substance in an amount to cause a reduction in the amount of surface- depositable calcium carbonate, but insufficient to cause a major increase in temperature of the water or water- containing liquid substance, or insufficient to heat the water or the water-containing liquid substance to a temperature above about 60-65°C.

38. An apparatus according to claim 37, wherein the conduit means comprise a tube section defining the pro- cessing zone and being adapted to be inserted in a water or a water-containing liquid substance supply conduit, the control means comprising a flow detector for detect¬ ing liquid flow in the supply conduit and switch means for activating the electromagnetic wave generator, when a water or a water-containing liquid substance flow is detected by the flow detector, and for inactivating the electromagnetic wave generator when no such flow is detected.

39. An apparatus according to claim 37, wherein the conduit means comprises a processing chamber defining said processing zone therein, the processing chamber having water or water-containing liquid substance inlet and outlet valves, and the control means being adapted to control the function of the valves and the function of the electromagnetic wave generator so as to cause water or water-containing liquid substance to flow in¬ termittently with a dwelling time in the processing chamber where it is exposed to electromagnetic radia¬ tion.

40. An apparatus according to any of the claims 37-39, wherein the conduit means comprise a main conduit and a branch conduit for branching of a flow of the water or the water-containing liquid substance from the main con¬ duit, the processing zone being defined by the branch conduit, which is united with the main conduit.

41. An apparatus according to claim 40, further compris¬ ing conduit means for recirculating at least part of the processed water or water-containing liquid substance through the processing zone.

42. An apparatus according to any of the claims 37-41, further comprising means for causing turbulence in the water or the water-containing liquid substance while it is being exposed to electromagnetic radiation in said processing zone.

43. An apparatus according to any of the claims 37-42, wherein the electromagnetic wave generator is adapted to generate electromagnetic waves with a frequency in the range from 200 to 300,000 MHz.

44. An apparatus according to claim 43, wherein the electromagnetic wave generator is adapted to generate electromagnetic waves with a frequency in the microwave region from 300 to 300,000 MHz.

45. An apparatus according to claim 44, wherein the electromagnetic wave generator is adapted to generate electromagnetic waves with a frequency in the range from 300 to 30,000 MHz.

46. An apparatus according to claim 45, wherein the electromagnetic wave generator is adapted to generate electromagnetic waves with a frequency in the range from 300 to 3000 MHz.

47. An apparatus according to claim 46, wherein the electromagnetic wave generator is adapted to generate electromagnetic waves with a frequency in the range from 1000 to 3000 MHz.

48. An apparatus according to claim 47, wherein the electromagnetic wave generator is adapted to generate electromagnetic waves with a frequency in the range from 2400 to 2500 MHz, preferably about 2450 MHz.

49. An apparatus according to claim 43, wherein the electromagnetic wave generator is adapted to generate electromagnetic waves with a frequency which is absorbed by one or more of Ca⁺⁺, C0₂ ^" ' HC0₃ ^"' C0₂, CaHC0₃ ⁺, H₂C0₃ and H₂0 in the water or the water-containing liquid substance.

50. An apparatus according to any of the claims 43-49, wherein the electromagnetic wave generator is adapted to generate electromagnetic energy which is substantially continuously transmitted to the water or the water-con¬ taining liquid substance when the electromagnetic wave generator is activated.

51. A water or a water-containing liquid substance con¬ taining dissolved calcium carbonate processed by the method claimed in any of the claims 1-36.

52. A water or a water-containing liquid substance ac¬ cording to claim 51, wherein the reciprocal of the ratio between the surface-depositable calcium carbonate in the water or the water-containing liquid substance and sur¬ face-depositable calcium carbonate in corresponding untreated water or water-containing liquid substance, as determined by the test described herein, is at least 1.1.