WO2013144634A1

WO2013144634A1 - Device, system and methods for treating and purifying liquids

Info

Publication number: WO2013144634A1
Application number: PCT/GB2013/050819
Authority: WO
Inventors: James Edward Delves
Original assignee: Quantock Associates Limited
Priority date: 2012-03-29
Filing date: 2013-03-28
Publication date: 2013-10-03
Also published as: GB2500664A; GB201205534D0

Abstract

A method of purifying a liquid to substantially remove pathogens from the liquid, comprising the steps of: a) applying electromagnetic radiation to the fluid, b) directing the fluid to flow around an electromagnetic source, c) exposing the fluid to silver, d) filtering the fluid using a filtration screen, e) applying ultrasound to the fluid.

Description

Title: Device, system and methods for treating and purifying liquids Field of the invention

The present invention relates to the treatment and purification of liquids. In particular, the present invention relates to a device for the purification of greywater, radioactive waste, and oil and gas drilling mud. Background

A major application of water treatment is to decrease the demand for fresh potable water locally and globally by allowing waste water to be re-cycled. This increases the likelihood that supply can match the demand. This is particularly important in developing countries where supply is often limited.

The treatment of "grey water" is of particular benefit. The term "grey water" is usually used to refer to the waste water left over from domestic use such as bathing, laundry or vehicle (e.g. car) washing, and is sometimes used to refer to rainwater and/or river water. Around 30% of the potable water supplied to a domestic household in the UK will become grey water. Correspondingly, approximately 30% of the potable water supplied to a household in the UK will be used for WC flushing. By collecting and treating grey water so that it can be re-used for WC flushing, demand for potable water for a particular household can therefore be reduced by approximately 30%. The treated grey water could also be used for other purposes such as garden irrigation, reducing demand even further.

Grey water must be treated before it is re-used. If stored untreated before subsequent re-use, the low levels of pathogen, e.g. bacteria, suspended in it will rapidly multiply. This is undesirable, particularly in a domestic or a healthcare environment, since it can cause unpleasant smells and poor sanitation. Untreated grey water is also not suitable for garden use since contaminants in the water, such as soaps and detergents, may be toxic.

There are several known physical (as opposed to chemical) techniques of treating water. These include, but are not limited to: the use of silver (e.g. as electrodes and/or filters), high frequency electromagnetic radiation (Ultraviolet or microwaves), ultrasonication, filtration, vortex separation and electrocoagulation. Silver has long been known to have a biocide effect and has been shown to kill bacteria in water and maintain water purity over long periods of time.

The application of electromagnetic radiation to bacteria and/or other

pathogens is known to disintegrate cells. The UV wavelength is sufficiently short to destroy DNA in microorganisms, killing them and preventing them from reproducing. Similarly, microwaves have been shown to destroy all marine life within the ballast water of ships tanks as well as to destroy viruses.

The application of electromagnetic radiation or sonication is also known to disintegrate pathogens, e.g. bacterial cells. The application of ultrasonic waves to a liquid causes cavitation in the liquid. The implosion of cavitation bubbles causes strong hydro-dynamic shear-forces. The shear-forces can disintegrate fibrous, cellulosic material into fine particles and break the walls of cell structures.

Filtration is usually achieved using a wire mesh with apertures of a selected size, the selected size being dependent on the size of the particulate matter it is desired to filter out of a liquid. Using current technology, it is possible to filter out extremely fine particulate matter, such as bacteria. Vortex separation, e.g. cyclonic separation, is a method of separating particles from a fluid without the use of filters. A rotating flow is established within a chamber and fluid flows in a pattern from the top to the bottom of the chamber. Larger, denser particles have too much inertia to follow the tight curve of the stream and strike the wall of the chamber, falling to the bottom where they can be removed. The particle size removed can be selected by controlling the flow rate and device geometry.

Electro-coagulation is a method of precipitating out ions (e.g. heavy metal ions) and/or colloids (of either an organic, inorganic or mixed organic/inorganic nature), using electrolysis. This method is known to remove 99.9% of heavy metals. Coagulation can be achieved by chemical or electrical methods. In an electro-coagulation process, the coagulant is generated in situ by electrolytic oxidation of an appropriate anode material. In this process, charged ionic species - metal ions and/or other charged entities - are removed from a fluid, e.g. water, by allowing the coagulant to react with ions having an opposite charge, or with a floe of, for example, metallic hydroxides generated within an effluent stream.

The characteristics of electro-coagulated floe differ dramatically from those generated by chemical coagulation. An electro-coagulated floe tends to contain less bound water, is more shear resistant and is more readily filterable.

In its simplest form, an electro-coagulation reactor is made up of an electrolytic cell with one anode and one cathode. When connected to an external power source, the anode material electrochemically corrodes due to oxidation, while the cathode is reduced. An electro-coagulation system essentially consists of pairs of conductive metal plates in parallel, which act as monopolar electrodes.

Iron and/or aluminum and/or alloys may be used as electrodes to continuously produce ions in the water. The released ions neutralize the charges of the particles and thereby initiate coagulation. The released ions remove undesirable contaminants either by chemical reaction and precipitation, or by causing the colloidal materials to coalesce, which can then be removed by a filter screen. There are various known problems associated with the use of each of the techniques for treating water mentioned above.

Electromagnetic radiation is less effective in purifying a fluid if the fluid contains large clumps of particulate matter. Pathogens, e.g. microorganisms, at the centre of large clumps are shielded from the radiation and will not be destroyed.

UV bulbs and filters, over time, become coated with a build up of particulate matter. This prevents them from working effectively and they must be cleaned or replaced regularly, disrupting the water treatment process.

Vortex separation, e.g. cyclonic separation, only has an efficiency rating of around 50% since particles larger than the target size will be removed with greater efficiency, and particles smaller than the target size will be removed with lesser efficiency. In addition, vortex separation is not effective in removing extremely small particles, such as bacteria and viruses; it is only really suited to the removal of generally large/dense particulate debris.

A common problem encountered during electro-coagulation is electrode fouling or passivation which causes the process to fail.

Usually chemical biocides, such as chlorine, are used in addition to the above physical techniques in order to ensure the destruction of all bacteria and viruses. However, many of these have been shown to have harmful effects for humans and wildlife. For example, chlorine is a known carcinogen. Combining some of these techniques goes some way towards solving the above problems. For example, using radiation in combination with vortex separation destroys bacteria, and also removes debris. However, combining technologies can cause further problems due to adverse affects of the two technologies acting together. A combination may also fail to fully solve the problems, for example, combining radiation and vortex separation would not solve the problem of build up of matter on the radiation transducer even though it may be more effective at treating the fluid.

The use of sonication to clean or prevent build up on solid objects is known. This technique can be applied to break down clumps of soft material. Sonication, in combination with filtration, could therefore potentially be used to solve the problem of solid matter build up on a means of producing radiation or on filter screens. However, the cavitation bubbles caused by the sonication would be expected to interfere with the effectiveness of the filtration because sonication would be expected to interrupt the uni-directional flow of the fluid through the filter. Vortex separation, e.g. cyclonic separation, and filtration could theoretically be combined. One way to do this would be to incorporate the mesh filtration screen as the walls of the chamber. However, this would be expected to present the problem that the filter screen walls would cause significant friction and reduce the velocity of the vortex. The effectiveness of the vortex separator at removing smaller particles would therefore be reduced. Furthermore, such a combination would be expected to cause increased build-up on the filter due to the radially outward (relative to the axis around which the liquid circulates) directed force generated by the vortex causing more particles to hit the filter per unit time. Silver could be utilised in combination with vortex separation in order to kill microbes at the same time as separating out particulates. For example, the walls of the chamber could be coated with silver. However, in this instance, contact time with walls of vortex separator is likely to be insufficient to allow a reaction with silver to occur, reducing the biocidal effect of the silver.

Electro-coagulation technology could also theoretically be combined with the other techniques mentioned above. However, if combined with electromagnetic radiation, the effectiveness of electro-magnetic radiation would be significantly reduced since by forming large clumps in the fluid, pathogens, e.g. bacteria, at the centre of the clumps would be shielded from the radiation and not broken down. Similarly, combining electro-coagulation with sonication would prevent either technique sonication having any effect. The electrocoagulation would result in larger clumps which would then be broken down by sonication straight away.

The present invention, in its various embodiments, some of which are described here, seeks to mitigate the problems encountered with previous devices and/or methods for treating fluids, e.g. grey water.

Brief summary of Invention

According to a first aspect of the present invention, there is provided a liquid purification device comprising: a chamber for forming a vortex in a liquid, the chamber comprising a wall, the wall comprising a filter; an electromagnetic radiation source; and an ultrasonic source; wherein the device is configured to substantially remove pathogens from a liquid. In one embodiment, the chamber for forming a vortex in a liquid is operable to induce a whirl component of velocity in a liquid. Velocity is comprised of a tangential component and a whirl component.

In one embodiment, the chamber for forming a vortex in a liquid is a cyclonic separator.

Preferably, further comprising an electro-coagulation reactor

Further preferably, wherein at least two of the components are configured to be active simultaneously.

Advantageously, wherein all of the components of the device are configured to be active simultaneously. Preferably, wherein the filter comprises a filtration screen.

Further preferably, wherein the filtration screen comprises wire mesh.

Advantageously, wherein the wire mesh is twill weaved.

Preferably, wherein the filter comprises silver.

Further preferably, wherein the filter includes an anode and a cathode. Advantageously, wherein the electromagnetic radiation source is a UV bulb or a microwave generator. Preferably, wherein the electromagnetic radiation source is contained within a quartz tube that is housed within the chamber. Further preferably, wherein the quartz tube is centrally located within the chamber.

Advantageously, wherein the ultrasonic source is a piezo transducer. Preferably, wherein the chamber for forming a vortex in a liquid is cylindrical or conical.

Further preferably, wherein the ultrasonic source is located such that fluid that has passed through the filter is exposed to ultrasound and located so that it displaces pathogens and/or particulate matter from the inner surface of the filtration screen.

Advantageously, wherein the apparatus is configured to be active

continuously.

Preferably, further comprising a helix located within the chamber, wherein the helix enhances the path of the liquid through the chamber.

Further preferably, further comprising a collecting means configured to collect the pathogens following removal.

Advantageously, wherein the collecting means is pressurized and the device is configured so that once the collecting means is substantially full of particulate matter it may be fluidly isolated from the system by means of a valve until a portion of the particulate matter has been removed from the collecting means. Preferably, further comprising a fluidizer configured to removed fluid from the collecting means.

In a further aspect of the present invention, there is provided a device according to the above for use in the treatment and purification of water, particularly grey water.

In a further aspect of the present invention, there is provided a device according to the above for use in the separation of radioactive matter from nuclear waste.

In a further aspect of the present invention, there is provided a device according to the above for use in the separation of oil and gas drilling mud in a liquid solution.

In a further aspect of the present invention, there is provided a device according to the above for use in any of the following processes: the treatment of effluent discharge at sewage treatment plants or industrial plants, emulsification, acceleration of chemical reactions, extraction removal of trapped gases, reduction of biofilm formation, accelerating the degradation of organic waste or the consumption of nitrate and phosphates, collecting paper pulp, or collecting and/or treating waste from tannery processes.

Preferably, wherein the device further comprises a pump configured to draw liquid through the device.

Further preferably, wherein the device is configured to be self-cleaning.

Advantageously, wherein at least the filter screen and the electromagnetic radiation source are cleanable. Preferably, wherein the pathogens are coliforms; optionally, E. coli and/or Cryptosporidium.

In a further aspect of the present invention, there is provided a system for purifying water, the system comprising a device according to the above.

In a further aspect of the present invention, there is provided a method of purifying a liquid to substantially remove pathogens from the liquid, comprising the steps of: a) applying electromagnetic radiation to the fluid,

b) directing the fluid to flow around an electromagnetic source, c) exposing the fluid to silver,

d) filtering the fluid using a filtration screen,

e) applying ultrasound to the fluid.

Preferably, wherein some of the steps are performed simultaneously.

Further preferably, wherein steps a), b), c) and d) are performed

simultaneously.

Advantageously, wherein steps a) and b) are performed simultaneously.

Preferably, wherein steps b) and d) are performed simultaneously.

Further preferably, wherein steps c) and d) are performed simultaneously.

Advantageously, wherein all of the steps a), b), c), d) and e) are performed simultaneously. Preferably, wherein the electromagnetic radiation source is ultraviolet or microwaves.

Further preferably, wherein the filtration screen is made from a wire mesh.

Advantageously, wherein the wire mesh is twill weaved.

Preferably, wherein the filtration screen further comprises silver. Further preferably, wherein the frequency of the ultrasonic pressure is variable.

Advantageously, further comprising exposing the fluid to chemical biocides. Preferably, wherein the method is for use in the treatment and purification of water, particularly grey water.

Further preferably, wherein the method is for use in the separation of radioactive matter from nuclear waste.

Advantageously, wherein the method is for use in the separation of oil and gas drilling mud.

Preferably, wherein the method is for use in any of the following processes: the treatment of final effluent discharge at sewage treatment plants or industrial plants, emulsification, acceleration of chemical reactions, extraction removal of trapped gases, reduction of biofilm formation, accelerating the degradation of organic waste or the consumption of nitrate and phosphates, collecting paper pulp, or collecting and/or treating waste from tannery processes. The present invention will now be described with reference to the following non-limiting embodiments.

FIGURE 1 is an isometric view of a device according to one embodiment of the invention.

FIGURE 2 is a schematic of a cross-section of the device shown in Figure 1 , in use, according to one embodiment of the invention. FIGURE 3 is a schematic of the inclusion of the device of Figure 1 configured within a system for the treatment of grey water in a domestic environment, according to one embodiment of the invention.

FIGURE 4 is a schematic of the device of figure 1 configured to capture solids, according to one embodiment of the present invention.

FIGURE 5 is a schematic of the device of figure 1 including a helix and two mesh filter screens according to one embodiment of the present invention. Description of Invention

In a preferred embodiment of the present invention, shown in figure 1 , the device (A) according to one embodiment of the present invention combines a number of fluid treatment processes into a single device (A). The device (A) allows continuous filtration of a fluid whilst the combined processes break down large particulates and eradicate pathogens, which may include coliforms, such as E. co//^' and Cryptosporidium, in the fluid.

The device (A) comprises several components which are configured in order to provide break down of particulate material (for example, from 1 to 2000 μηι, and/or any intermediate amount, in size) and eradication of pathogens. The device (A) comprises an inlet port (1 ), through which liquid to be treated can be introduced into the device (A). The inlet port (1 ) is located towards the top of the device (A) when the device is in use, and feeds tangentially into a part of the device (A), which is a chamber (10) for forming a vortex in a liquid.

In most domestic situations, the liquid is untreated water, e.g. grey water.

Located centrally within the chamber (10) is an inner container (3), containing a source of electromagnetic radiation (e.g. in some embodiments a source of UV light and/or microwaves). Preferably, the inner container (3) is made from quartz, or another generally inert material such as glass or a plastics material, in order to avoid liquid coming into direct contact with the source of

electromagnetic radiation, while still allowing the electromagnetic radiation to penetrate the liquid. The source of electromagnetic radiation can be inserted into the device (A) through an entry port (7). The entry port (7) can, in alternative embodiments, be through any of the side walls of the device (A).

The walls of the device (A) comprise an inner filtration means (5), such as a filtration screen. Preferably, the filtration means (5) comprises a wire mesh, which may be formed using a twilled weave process. Preferably, the filtration means (5) comprises silver.

In a preferred embodiment, the filtration means (5) comprises two mesh filtration screens: an inner filtration mesh screen (as shown in the embodiment of figure 1 ; which can be configured to be an anode, in certain embodiments) comprising silver or silver alloy content, and an outer filtration mesh screen (not shown in figure 1 ; which can be configured to be a cathode in certain embodiments) comprising silver or silver alloy content. The inner filtration mesh screen in particularly preferred embodiments, exemplified in figure 5, has a greater mesh spacing than the outer filtration mesh screen. In other words, the inner filter screen is a coarse filter screen, e.g. 100 micron apertures, and the outer filter screen is a fine filter screen (relative to the inner filter screen), e.g. 20 micron apertures, in some preferred embodiments. The aperture size can vary depending on the liquid to be treated and the

contaminant loading of that liquid.

The incoming liquid may be introduced into a helix (exemplified in figure 5) installed between the inner container (3) and the filtration screen, within the chamber (10).

An annulus (9) is formed between the inner screen and the outer tube (8) of the device (A). Piezo processors (4), or another form of ultrasonic transducers, are situated on the surface of the outer tube (8) to emit ultrasonic waves into the annulus (9). Particulates can be discharged through a port (6) through a side wall of the device (A). In use, the port (6) is situated at the bottom of the device (A) so that particulate matter can fall through the liquid, under the influence of gravity, and through the port (6). Treated liquid leaves the device (A) through the outlet port (2), which is located near the top of the device (A), in use. The outlet port is located at the top of device (A), in use, to ensure that the chamber operates in a flooded, i.e. generally full, environment.

Figure 2 shows a schematic cross section of the device (A) when in use.

Untreated liquid is pumped or drawn through the inlet (1 ) into the chamber. As the liquid enters the chamber the liquid is exposed to electromagnetic radiation, such as UV light or microwaves, as it passes the inner container (3).

A vortex is generated in the chamber by the fluid taking its natural path through the chamber from the tangentially placed inlet port. In preferred embodiments the chamber is cylindrical or conical to assist in the formation of a vortex because the fluid will then flow in a pattern from the top to the bottom of the chamber. This flow is further enhanced by having the inner core (3) of quartz glass within the chamber, and, in some embodiments, by the helix surrounding the quartz core.

This flow maximises the exposure of the fluid entering the device (A) to the electromagnetic radiation source housed within the inner core (3). In embodiments where the incoming liquid phase is contained in a helix (as exemplified in figure 5) installed between the inner container (3) and filter screen (5), the helix ensures that all incoming liquid is exposed in a controlled manner to maximise the exposure to sonication and the electromagnetic radiation source. The helix may also provide support for the mesh screen which in some cases can be a very fine mesh.

The vortex motion of the fluid in the chamber also results in partial separation (by cyclonic separation) because it causes large and dense particles with a high inertia settle by gravity to the bottom of the chamber (10).

The fluid path causes the fluid in the chamber to migrate to the walls of the chamber. This forces the liquid through the mesh filter screen and into the outer chamber. The combination of the fluid path with the filter causes significantly improved filtration compared to standard filtration techniques.

In embodiments where the mesh filtration screen comprises silver, for example, the mesh is coated with silver or contains silver within the weave of the filter, whilst being filtered the fluid is also exposed to the silver, which has a biocidal effect.

In certain embodiments where the mesh filtration screen comprises two mesh filter screens, which in some embodiments are an anode screen and a cathode screen, fluid is first forced through the coarse mesh (anode) screen, which may contain silver. A direct current is then passed through the inner (anode) to the outer cathode fine screen. Measuring resistance across the inner and outer screen allows an operator to know when to replace screens. As liquid passes through to the outer (cathode) fine screen an electrocoagulation process occurs which causes a proportion of the contaminants to coagulate and increase in size to allow the fine (cathode) screen mesh to filter and contain the contaminants within the chamber between the two screens.

In some, alternative, embodiments, a chemical coagulant can be added to the liquid, rather than having an anode screen and a cathode screen, to facilitate coagulation of particulate matter.

Particulate is trapped and contained within the chamber between the screens, whilst simultaneously the ultrasonic cavitational bubbles, caused by affecting the piezo processors displace the contaminants from the inner face of the outer mesh screen. This particulate matter is allowed to settle by gravity to the bottom of the chamber (when considered in the general direction shown in use in figures 1 and 4) for disposal.

Particulates with a high inertia fall to the bottom of the chamber and are discharged through the discharge port. However, some particulates may be trapped and contained within the inner mesh screen. In a preferred

embodiment, ultrasonic pressure is emitted by piezo transducers fixed to the outside of the device (A). Other means for producing ultrasonic waves may be used. These waves cause cavitation bubbles in the annulus. The cavitation bubbles, when they collapse, generate micro-jets of liquid that can travel up to 15 metres per second. The micro-jets pass through the treated liquid and through the apertures of the mesh screen to remove any particulate

contamination from the inner face, relative to the inner container, of the mesh screen. These contaminants are allowed to settle by gravity to the bottom of the chamber where they are discharged through the port. Filtration through the filter screen(s) in the opposite direction to the micro-jets is not impeded as the velocity of the filtering liquid is much lower than the micro-jets and the mass of filtering liquid is much greater.

The use of sonication therefore means that the device (A) is self-cleaning. The action of the micro-jets continually removes deposited contaminants from the inner surface of the filter screen and so prevents the problem of build-up on the walls of the chamber, which might otherwise be envisaged. Using a wide range of frequencies, the cavitational bubbles size can be changed in size to suit any particular process; the bubbles normally have a size range of up to 20 micron and as such can pass through a mesh screen 20 micron and above. Since, contaminants are pushed off the filter screen into the chamber, this permits more particulates to be removed more efficiently.

The use of sonication in combination with electro-coagulation helps to keep the electrodes clear from fouling.

The advantage of the device being self-cleaning is that the component parts, e.g. the mesh filter or the UV bulb, do not need to be cleaned or replaced. This allows the process to be continuous, increasing yield and efficiency while reducing maintenance costs and inconvenience caused. The system is capable of self-cleaning whilst operating and treating liquids.

The sonication also causes a purifying effect on the treated liquid. Once filtered, the fluid passes into the annulus (9), where it is exposed to cavitational bubbles. These breakdown any remaining pathogens, for example coliforms such as E. coli or Cryptosporidium that was not destroyed by the previous processes. The bubbles rupture the cells of the pathogens, killing the cells and preventing reproduction. Another unexpected advantage of the present invention is that the combined use of electromagnetic radiation and sonication is more effective at disintegrating cellular material than either is alone or in sequence. Prior art devices typically use only one of these techniques. However, it has

unexpectedly been found that the combination of these processes results in a reduction in the number of large particles. This increases the effectiveness of the UV light of microwave radiation application since fewer microorganisms are shielded in the centre of conglomerated matter. Furthermore, the cavitation caused by the sonication causes sonoluminescence which releases more UV light, which, depending on its wavelength, may cause further bacterial breakdown, making the system more efficient. Overall this means that the exposure time required to treat the fluid is significantly reduced. This reduces the energy demands of the device compared with the prior art.

In addition, sonication allows for a sonochemical reaction to take place at the surface of the silver screen which catalyses the reaction with silver and allows the silver to act as an effective biocide despite the short exposure time.

One advantage of electro-coagulation is that treatment of liquids, e.g.

wastewater, by electro-coagulation gives palatable, clear, colorless and odorless water. Sludge formed by electro-coagulation tends to be readily settable and easy to de-water, because it is composed of mainly metallic oxides/hydroxides. The electro-coagulation process also has an advantage over chemical coagulation of removing generally small colloidal particles, because the applied electric field sets them in faster motion, thereby facilitating the coagulation.

The device of the present invention does not require chemicals or biocides to kill bacteria. However, these can be used in combination with the device of the present invention, in which case the device confers a further unexpected advantage. The use of sonication means that the device functions to catalyse the breakdown of pathogens, e.g. microorganisms. The combination of multiple purification means within a single device provides for a synergistic combination which allows for advantageous processing, e.g. purification, of liquids, e.g. grey water.

In the case of water treatment, the waste particulate which is separated from the water is rendered generally inert after processing through a device of the present invention and can be used as landfill without being subjected to landfill tax, in many jurisdictions.

In a preferred embodiment, a device according to the present invention, e.g. device (A) as discussed above, is configured within a purification system (B) to purify grey water within a domestic environment, as shown in figure 3 (without valves or controls). Grey water from, for example, a bath, shower or hand basin is discharged into an accumulation tank to allow a controlled flow of grey water into the device (A).

Treated grey water from the device (A) is pumped to a high level treated water tank to allow the treated water to be fed by gravity to one or more WC cisterns or to an outside tap for garden use.

Any particulate or contaminants removed from the grey water are periodically discharged to the waste foul drain. In the event that insufficient treated grey water is available for WC flushing then a mains water supply allows sufficient mains water to serve the WC.

Domestic installation of the device (A) therefore brings benefit to households by reducing the usage of fresh water and therefore reducing water bills. It also benefits water companies since existing infrastructures for water treatment, waste water treatment plants and drainage and water distribution infrastructure have a reduced load. This should allow more housing and industrial

developments without the need to upgrade existing plant and therefore reduce capital expenditure in the medium term. The devices of the present invention can be used in a wide variety of applications, other than for domestic purification systems, as shown in Figure 4. Use of a device (A) according to the present invention in water treatment plants to treat effluent discharge provides a substantial reduction of total suspended solids, turbidity, biochemical oxygen demand and chemical oxygen demand in treated water discharged to the environment. Further uses include in emulsification, acceleration of chemical reactions and the extraction and/or removal of trapped gases, reduction of biofilm formation, accelerating the degradation of organic waste, the consumption of nitrate and phosphates, and the treating/recycling of waste water produced during vehicle, e.g. car washing.

Devices according to the present invention can also be used in processes where the aim is to collect removed sediment rather than treated fluid. For example, devices according to the present invention have applications in the filtration of radioactive material from nuclear waste. Another example of the uses of the devices of the present invention is in the purification of oil and gas drilling mud or ballast water, for example as shown in figure 4, where the ultrasonic bubbles infiltrate solids within the water to be treated to remove oil from within the pores and voids of the solids; this permits the oil to be removed with the liquid phase and the substantially cleaned solids captured in a solids accumulation vessel. It may also be desirable to use device (A) to collect paper pulp, collect and/or treat waste from tannery processes, or collect and/or treat waste water discharge from industrial processes. As shown in figure 4, a mixture of solids and liquid is fed into the device (A) to allow the solids within the starting mixture to fall out of the bottom of the device (A) and into a solids accumulation vessel. When sufficient solids have accumulated in the vessel, the interconnecting valve V1 can be closed. Liquid can then be fed into the fluidising unit to pressurize the vessel and allow accumulated solids to be removed at a controlled slurry concentration and discharged for treatment upstream.

Collected radioactive wastes may be fed to an encapsulation process or to a long term storage pond.

Following discharge of the solids, feed to the fluidiser is closed and valve V1 opened to allow solids accumulated in the device (A) to settle into the solids accumulation vessel by gravity. There is not necessarily a pressure differential between the device (A) and the solids accumulation vessel during the separation process so solids may settle under gravity.

In all embodiments, the device (A) may be configured to permit the UV light generator or magnetic radiation generator to be removed or interchanged.

In all embodiments, using a pump (not shown) to draw liquid through the device (A) produces a pressure within the device (A) which enhances and assists the generation of cavitational bubbles by the piezo transducers by creating a negative pressure environment.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components. The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

A liquid purification device comprising: a chamber for forming a vortex in a liquid, the chamber comprising a wall, the wall comprising a filter; an electromagnetic radiation source; and an ultrasonic source; wherein the device is configured to substantially remove pathogens from a liquid.

The device of claim 1 , further comprising an electro-coagulation reactor.

The device of claim 1 or 2, wherein at least two of the components are configured to be active simultaneously.

The device of claim 1 or 2, wherein all of the components of the device are configured to be active simultaneously.

The device of any one of the previous claims, wherein the filter comprises a filtration screen.

6. The device of claim 5, wherein the filtration screen comprises wire

mesh.

7. The device of claim 6, wherein the wire mesh is twill weaved.

8. The device of any one of the previous claims, wherein the filter comprises silver.

9. The device of any one of the previous claims, wherein the filter includes an anode and a cathode.

10. The device of any one of the previous claims, wherein the

electromagnetic radiation source is a UV bulb or a microwave

generator.

1 1 . The device of any one of the previous claims, wherein the

electromagnetic radiation source is contained within a quartz tube that is housed within the chamber.

12. The device of claim 12, wherein the quartz tube is centrally located

within the chamber.

13. The device of any one of the previous claims, wherein the ultrasonic source is a piezo transducer.

14. The device of any one of the previous claims, wherein the chamber for forming a vortex in a liquid is cylindrical or conical.

15. The device of any one of the previous claims, wherein the ultrasonic source is located such that fluid that has passed through the filter is exposed to ultrasound and located so that it displaces pathogens and/or particulate matter from the inner surface of the filtration screen.

16. The device of any one of the previous claims, wherein the apparatus is configured to be active continuously.

17. The device of any one of the previous claims, further comprising a helix located within the chamber, wherein the helix enhances the path of the liquid through the chamber.

18. The device of any one of the previous claims, further comprising a

collecting means configured to collect the pathogens following removal.

19. The device of claim 18, wherein the collecting means is pressurized and the device is configured so that once the collecting means is

substantially full of particulate matter it may be fluidly isolated from the system by means of a valve until a portion of the particulate matter has been removed from the collecting means.

20. The device of claim 19, further comprising a fluidizer configured to

removed fluid from the collecting means.

21 . The device of any one of the previous claims for use in the treatment and purification of water, particularly grey water.

22. The device of any one of the previous claims for use in the separation of radioactive matter from nuclear waste.

23. The device of any one of the previous claims for use in the separation of oil and gas drilling mud in a liquid solution.

24. The device of any one of the previous claims for use in any of the

following processes: the treatment of effluent discharge at sewage treatment plants or industrial plants, emulsification, acceleration of chemical reactions, extraction removal of trapped gases, reduction of biofilm formation, accelerating the degradation of organic waste or the consumption of nitrate and phosphates, collecting paper pulp, or collecting and/or treating waste from tannery processes.

25. The device of any one of the previous claims, further comprising a pump configured to draw liquid through the device.

26. The device of any one of the previous claims, wherein the device is configured to be self-cleaning.

27. The device of claim 26, wherein at least the filter screen and the

electromagnetic radiation source are cleanable.

28. The device of any one of the previous claims, wherein the pathogens are coliforms; optionally, E. coli and/or Cryptosporidium.

29. A device a substantially hereinbefore described with reference to any one of the figures.

30. A system for purifying water, the system comprising a device according to any one of the previous claims.

31 .A method of purifying a liquid to substantially remove pathogens from the liquid, comprising the steps of: a) applying electromagnetic radiation to the fluid, b) directing the fluid to flow around an electromagnetic source, c) exposing the fluid to silver, d) filtering the fluid using a filtration screen, e) applying ultrasound to the fluid.

32. The method of claim 31 , wherein some of the steps are performed simultaneously.

33. The method of claim 32, wherein steps a), b), c) and d) are performed simultaneously.

34. The method of claim 31 , wherein steps a) and b) are performed

simultaneously.

35. The method of claim 31 , wherein steps b) and d) are performed

simultaneously.

36. The method of claim 31 , wherein steps c) and d) are performed

simultaneously.

37. The method of claim 31 , wherein all of the steps a), b), c), d) and e) are performed simultaneously.

38. The method of any one of claims 30-37, wherein the electromagnetic radiation source is ultraviolet or microwaves.

39. The method of any one of claims 30-38, wherein the filtration screen is made from a wire mesh.

40. The method of claim 39 wherein the wire mesh is twill weaved.

41 . The method of any one of claims 39 or 40, wherein the filtration screen further comprises silver.

42. The method of any one of claims 30-41 , wherein the frequency of the ultrasonic pressure is variable.

43. The method of any one of claims 30-42, further comprising exposing the fluid to chemical biocides.

44. The method of any one of claims 30-43, for use in the treatment and purification of water, particularly grey water.

45. The method of any one of claims 30-44, for use in the separation of radioactive matter from nuclear waste.

46. The method of any one of claims 30-45, for use in the separation of oil and gas drilling mud.

47. The method of any one of claims 30-46, for use in any of the following processes: the treatment of final effluent discharge at sewage treatment plants or industrial plants, emulsification, acceleration of chemical reactions, extraction removal of trapped gases, reduction of biofilm formation, accelerating the degradation of organic waste or the consumption of nitrate and phosphates, collecting paper pulp, or collecting and/or treating waste from tannery processes.

48. The device of any one of claims 1 -30 for use in the method of any one of claims 30-47.

49. Any novel feature or combination of features disclosed herein.