WO2012050447A2

WO2012050447A2 - Method, device and system for limiting biological growth

Info

Publication number: WO2012050447A2
Application number: PCT/NL2011/050699
Authority: WO
Inventors: Cornelius Petrus Maria Luykx
Original assignee: Luykx Patenten B.V.
Priority date: 2010-10-12
Filing date: 2011-10-12
Publication date: 2012-04-19
Also published as: NL2005505C2; NL2007583A; NL2007583C2; WO2012050447A3

Abstract

The present invention relates to a method for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth, in fluids, comprising steps for: applying a sound generator for generating sound waves at preferably ultrasonic frequencies; generating by means of the sound generator sound waves with an intensity which causes damage to the biological growth; performing measurements in respect of the fluids for the purpose of obtaining at least one indicator value relating to the biological growth, and controlling the sound generator on the basis of the at least one indicator value.

Description

METHOD, DEVICE AND SYSTEM FOR LIMITING BIOLOGICAL GROWTH

The present invention relates to a method for limiting microbial growth, biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth, in fluids. The present invention also relates to a device for this purpose. The present invention also relates to a purifying system for purifying a fluid, such as water, from an industrial process or contaminated in other manner .

It is per se known that living cell material can be damaged by delivering a dose of ultrasonic energy. This principle is applied in per se known manner in throughflow systems for purifying water wherein bacteria are killed by the influence of damage caused by the dose of ultrasonic energy. Continuous dosage of ultrasonic energy is necessary in such throughflow systems in order to damage/kill the living cells flowing by.

The present invention is based on a surprising new insight that this principle for killing bacteria could be applicable for the purpose of preventing biological growth in large masses of water at locations where such biologi^¬ cal growth forms a nuisance. In the case of for instance settling basins of water treatment systems it is necessary to satisfy guality requirements in respect of the finally discharged water. Unrestrained biological growth in the settling basin results in an unacceptable water quality, among other reasons because of (fouling) growth of algae.

The present invention provides for this purpose a method for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth, in fluids, comprising steps for: - applying a sound generator for generating sound waves at preferably ultrasonic frequencies,

- generating by means of the sound generator sound waves with an intensity which causes damage to the biological growth,

- performing measurements in respect of the fluids for the purpose of obtaining at least one indicator value relating to the biological growth, and

- controlling the sound generator on the basis of the at least one indicator value.

In order to apply sound waves in large masses of water an expensive high-power sound generator is required so that the damaging effect can be extended over a great distance or in a large volume. Examples hereof are settling ponds with a size of several hectares.

An advantage of the system according to the present invention is that the lifespan of the sound generator can be lengthened by supplying energy on the basis of need or desirability instead of continuously. When a sound generator need be activated only a part of the time, the lifespan can be extended correspondingly. A lifespan of for instance about a year can be extended here to for instance 5 to 15 years. In addition to the cost benefit in respect of the replacement value, this is advantageous in the case such systems have to be employed distributed over the large body of water.

In a first preferred embodiment according to the present invention the measurements relate to measurements in respect of quantities of fouling substances, organisms or parts thereof present or a BOD value. BOD is an acronym for biological oxygen demand in the context of growth/life present in water and consuming a quantity of oxygen. For the discharge of waste water purified in settling basins limitations usually apply in respect of for instance the BOD value for the purpose of protecting the surface water in the vicinity. The BOD value is determined by, among other factors, the amount of biological (fouling) growth (of for instance algae) in the settling basins. Such values in respect of the use of the sound generator can be optimized by means of the present embodiment.

In a further alternative embodiment the measurements relate to measurements in respect of the transparency, the pH value, an EC value or an electrical conductivity. Control of the sound generator is more preferably performed by means of varying the supplied power.

In a further embodiment the control of the sound generator is performed on the basis of activating and deactivating of the sound generator for intervals of time. By means of such embodiments the lifespan of the sound generator is correspondingly increased in the stated manner .

A further aspect of the present invention relates to a method for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth, in fluids, comprising steps for:

- applying a sound generator for generating sound waves at preferably ultrasonic frequencies,

- generating by means of the sound generator sound waves with an intensity which causes damage to the biological growth, wherein:

- the method is applied in surface water, such as a settling pond, such as a settling pond intended for settling therein of turbidity originating from a cooling tower, such as at a sugar refinery. An advantage of such an embodiment is that such a surface water can be regulated in specific manner, or the biological growth can be limited.

In a further preferred embodiment the sound generator has a power greater than 10 W, more preferably greater than 200 W, more preferably greater than 500 W, more preferably greater than 1000 W, more preferably greater than 1500 W, more preferably greater than 1800 W, more preferably greater than 2000 W.

Alternatively, the sound generator has a power lower than 100,000 , more preferably lower than 50,000 , more preferably lower than 20,000 W, more preferably lower than 10,000 W, more preferably lower than 5000 W, more preferably lower than 3000 .

Such high-power sound generators are expensive de^¬ vices whose remaining lifespan is important. Replacement costs are also considerable, among other reasons because of the location on surface water. The present invention functions for the purpose of saving such costs.

The method according to the present invention more preferably comprises steps for applying the sound genera^¬ tor from a floating unit which can be arranged on the fluid, preferably at one or more positions distributed with predetermined regularity on the surface water. It hereby becomes possible to treat such a surface water with a min^¬ imum number of sound generators.

More specific steps are provided for applying a cooling system on the basis of a solid-state principle for a control unit of the sound generator. A maintenance-free system can hereby be applied.

Rigid plastic materials are more preferably applied, such as PVC and the like, in the device, such as in floats of the floating unit. The high-freguency sounds ap- plied result in premature deterioration of metals when these are used. The use of rigid plastic materials such as PVC results in a durable structure of the device.

A further aspect according to the present invention relates to a device for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth, in fluids, comprising:

- a sound generator for generating sound waves at preferably ultrasonic frequencies,

- a control unit, such as an amplifier, for the sound generator, wherein

- the control unit comprises input means for inputting information in respect of at least one indicator value relating to a fluid.

Advantages as stated in the foregoing with reference to embodiments of a method can be provided by means of such a device.

A further aspect of the present invention relates to a purifying system for purifying a fluid, such as water from an industrial process or contaminated in other manner, comprising a settling basin for settling of particles of matter therein, and comprising a device for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth according to the present invention, wherein the input means for inputting information in respect of at least one indicator value relating to a fluid is optional. Advantages as stated in the foregoing with reference to other aspects can be provided by means of such a system according to the present invention .

Further advantages, features and details of the present invention will be described in greater detail hereinbelow on the basis of one or more preferred embodi- ments with reference to the accompanying figures. Similar, though not necessarily identical components of different preferred embodiments are designated with the same reference numerals.

Fig. 1A and B show schematic representations in a cross-section and a top view of a preferred embodiment according to the present invention.

Fig. 2 shows an example of a sound generator for application in the present invention.

Fig. 3 shows a schematic representation of an application according to the present invention.

Fig. 4 shows a schematic representation of a further application according to the present invention.

Fig. 5 shows a block diagram of an embodiment according to the present invention.

A first preferred embodiment (Fig. 1) according to the present invention relates to a floating device for providing ultrasonic signals 1 for the purpose of damaging living cells in a mass of water on which the floating device is arranged. The floating device for providing ultrasonic signals 1 comprises a float 3 which in top view forms substantially a rectangle around a housing 4 for a control box 2 and a signal generating unit 11. Float 3 serves to impart buoyancy to the device.

The housing is constructed from a lower plate 12 and a cover plate 14. Both plates are attached to the floats by means of a bolt connection 7. Together the two plates also form housing 4. Control box 2 arranged in housing 4 serves to provide an electric signal to signal generating unit 11. This signal is a high-frequency signal with a frequency above the frequency audible to humans, such as for instance above 18,000 Hz, preferably above 20,000 Hz. The control box comprises for this purpose an amplifier able to provide such a signal. Such an amplifier can be constructed similarly to an audio amplifier. For the purpose of the necessary power referred to in the foregoing a corresponding cooling is required. Such a cooling can for instance be realized by means of cooling fins 15 or by means of a thermal contact with the mass of water on which the device floats. Such a thermal contact can be realized by means of cooling elements extending in the water. Alternatively, water cooling by means of a throughflow circuit is possible.

Fig. 2 shows an example of a signal generating unit 11. A piezo-element is arranged in housing 12. The piezo-element provides the vibrations with the stated power. The piezo-element is coupled by means of a coupling element 13 to an energy transfer element 14. This energy transfer element is substantially an elongate rod 17 having integrally arranged flanges thereon with curved transition surfaces 15, 16. These transition surfaces transmit the energy to the mass of water. Other forms of the energy transfer element are possible if they are suitable for transferring the energy to the fluid.

Fig. 3 and 4 show top views of arrangements of floating devices 1 in a settling basin 30. In Fig. 3 the basin is a rectangular basin with a water feed 31 and a water discharge 32. This is a settling basin in which the water is substantially at rest, either because the water feed and water discharge are only used occasionally or because the ratio of the water throughflow and the water volume is such that there is hardly any current.

The arrangement of the two floating devices 1 is such that the whole water volume can be reached in optimum manner by means of the sound waves. This is also the case in the variant of Fig. 3. In this variant there is already an increased concentration of living cells present in the inflowing water at water feed 31. These are damaged with a greater energy supply due to the arrangement of the two floating devices close to the water feed. The remaining part of the surface and the volume of the basin are treated by means of the third floating device.

The operation of a system according to the present invention is further elucidated with reference to Fig. 5. The signal generating unit 11, which is situated in the fluid during use, receives the signals from amplifier 54 located in control box 2. The signals are fed to the amplifier from a signal generator 55. Provided for the purpose of activating the signal generator and the amplifier are input means 56 for receiving an input from sensors 52, 52'. Input means 56 can receive signals from sensors at^¬ tached directly to floating device 1. It is however also possible for input means 56 to comprise a wireless receiver for receiving signals from a central measuring station, wherein switching of the signal generator and the amplifier takes place on the basis of signals received by the receiver. In alternative manner it is possible for the signals to be based on a predetermined time-switching, for instance on the basis of information relating to the growth of the biological material based on benchmarks such as the ambient temperature and climatological conditions.

The present invention is described in the foregoing with reference to several embodiments. The range and scope of the appended claims are not limited thereto. In alternative manner the treatment of water in a water storage in a bottling plant is for instance also possible according to the present invention. An example of an application according to the present invention is the protection of the inner side of underwater constructions, such as the inner side of hollow tubes of wind turbines placed in bodies of water. In the interior of such constructions there is usually enclosed water having no or minimum exchange with the outside. In such enclosed water there occurs microbial growth which can in turn contribute toward causing corrosion of the construction, for instance by producing radicals or acids. Damaging and/or killing such microbial growth on the basis of measurements provides an optimization between the use of the invention and damage to the construction by the mi^¬ crobial growth.

A further example of an application according to the present invention is the protection of the outer side of bodies floating in water, such as ships. A part or the whole of the bottom of a ship can be kept free of biological fouling by means of arranging a signal generating unit. A signal generating unit is preferably arranged on both sides of a hull, such as midships, or multiple devices in the case of a long hull. The hull can hereby be kept relatively clean. Just as in the above described applica^¬ tions, switching of the signal generating device on the basis of a measurement increases the lifespan. In such an application in the case of ships, powers between 10 and 300 W, preferably between 50 and 120 , more preferably between 60 and 80 W are provided, although this power can be adjusted subject to size and the desirability of placing a number of devices. Advantages achieved by keeping the hull clean include a considerable saving in the propulsion fuel.

A further advantage of activating the signal generating unit on the basis of a measurement is that activa- tion of the signal generating unit and deactivation thereof are not forgotten, and use can hereby be optimized. At a determined navigation speed no fouling growth will take place, so that deactivation on the basis of the speed of a ship is advantageous. A further advantage is for instance deactivation on the basis of a temperature. Fouling growth generally takes place only at relatively high temperatures, on the basis of which the signal generating unit can be activated above for instance an optionally empiri- cally determined threshold value. It is usually sufficient to treat a ship during part of the time period the ship spends in port.

Also provided for is that the temperature of the water and/or the speed of the water relative to the ship is measured for the purpose of providing input values for activation or deactivation of the signal generating unit. The above discussed measurements can also be applied in the case of a ship. When waters with a high BOD value are being navigated, the growth of the fouling can take place more rapidly than in waters with a low BOD value. The presence of a certain degree of fouling in the water is also a factor influencing activation of the signal generating unit.

The present invention has been described in the foregoing on the basis of several preferred embodiments. Different aspects of different embodiments are deemed described in combination with each other, wherein all combinations which can be deemed by a skilled person in the field as falling within the scope of the invention on the basis of reading of this document are included. These preferred embodiments are not limitative for the scope of protection of this document. The rights sought are defined in the appended claims.

Claims

1. Method for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth, in fluids, comprising steps for:

2. Method as claimed in claim 1, wherein the measurements relate to measurements in respect of quantities of fouling substances, organisms or parts thereof present or a BOD value.

3. Method as claimed in claim 1 or 2, wherein the measurements relate to measurements in respect of the transparency, the pH value, an EC value or an electrical conductivity.

4. Method as claimed in claim 1, 2 or 3, wherein control of the sound generator is performed by means of varying the supplied power.

5. Method as claimed in one or more of the foregoing claims, wherein the control of the sound generator is performed on the basis of activating and deactivating of the sound generator for intervals of time.

6. Method for limiting biological growth and/or biological fouling, such as micro-organisms or small

(fouling) growth, in fluids, comprising steps for:

- the method is applied in surface water, such as a settling pond, such as a settling pond for settling therein of turbidity originating from a cooling tower, such as at a sugar refinery.

7. Method as claimed in claim 6, comprising steps according to the method as claimed in claim 1 or more of the claims 1-5.

8. Method as claimed in one or more of the foregoing claims, wherein the sound generator has a power greater than 10 W, more preferably greater than 200 W, more preferably greater than 500 W, more preferably greater than 1000 W, more preferably greater than 1500 , more preferably greater than 1800 W, more preferably greater than 2000 W.

9. Method as claimed in one or more of the foregoing claims, wherein the sound generator has a power lower than 100,000 , more preferably lower than 50,000 W, more preferably lower than 20,000 W, more preferably lower than 10,000 W, more preferably lower than 5000 W, more preferably lower than 3000 W.

10. Method as claimed in one or more of the foregoing claims, comprising steps for applying the sound generator from a floating unit which can be arranged on the fluid, preferably at one or more positions distributed with predetermined regularity on the surface water.

11. Method as claimed in one or more of the foregoing claims, comprising steps for applying a cooling system on the basis of a solid-state principle for a control unit of the sound generator.

12. Method as claimed in one or more of the foregoing claims, comprising steps for applying rigid plastic materials, such as PVC and the like, in the device, such as in floats of the floating unit.

13. Method as claimed in one or more of the foregoing claims, comprising steps for measuring a speed of the fluid relative to the sound generator, preferably for the purpose of combatting biological fouling on the hull of a ship.

14. Device for limiting biological growth and/or biological fouling on the skin of a ship, comprising:

- at least one sound generator for generating sound waves at preferably ultrasonic frequencies, the sound generator being suitable for generating sound waves with an intensity which causes damage to the biological fouling, - measuring means for providing measurement data in respect of the fluids for the purpose of obtaining at least one indicator value relating to the biological growth, and

- control means for the sound generator on the ba sis of the at least one indicator value.

15. Device for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth, in fluids, comprising:

- a control unit, such as an amplifier, for the sound generator, wherein

16. Device as claimed in claim 14 or 15, comprising means for implementing measures as set forth in one or more of the claims 1-12.

17. Purifying system for purifying a fluid, such as water from an industrial process or contaminated in other manner, comprising a settling basin for settling of particles of matter therein, and comprising a device for limiting biological growth and/or biological fouling, such as micro-organisms or small (fouling) growth according to claim 13 or 14, wherein the input means for inputting information in respect of at least one indicator value relating to a fluid is optional.