EP2125631A1 - Système de traitement de liquide - Google Patents

Système de traitement de liquide

Info

Publication number
EP2125631A1
EP2125631A1 EP07824637A EP07824637A EP2125631A1 EP 2125631 A1 EP2125631 A1 EP 2125631A1 EP 07824637 A EP07824637 A EP 07824637A EP 07824637 A EP07824637 A EP 07824637A EP 2125631 A1 EP2125631 A1 EP 2125631A1
Authority
EP
European Patent Office
Prior art keywords
electrodes
liquid
outlet
inlet
array
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP07824637A
Other languages
German (de)
English (en)
Inventor
Alexander Simpson
Paul Wilkins
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atranova Ltd
Original Assignee
Atranova Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Atranova Ltd filed Critical Atranova Ltd
Publication of EP2125631A1 publication Critical patent/EP2125631A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
    • C25B11/031—Porous electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B15/00—Operating or servicing cells
    • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/60—Constructional parts of cells
    • C25B9/63—Holders for electrodes; Positioning of the electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/70—Assemblies comprising two or more cells
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/467—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction
    • C02F1/4672—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrochemical disinfection; by electrooxydation or by electroreduction by electrooxydation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46133—Electrodes characterised by the material
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46152—Electrodes characterised by the shape or form
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46152—Electrodes characterised by the shape or form
    • C02F2001/46157—Perforated or foraminous electrodes
    • C02F2001/46161—Porous electrodes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/4611—Fluid flow
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/4612—Controlling or monitoring
    • C02F2201/46125—Electrical variables
    • C02F2201/4613—Inversing polarity
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/4612—Controlling or monitoring
    • C02F2201/46145—Fluid flow
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/46—Apparatus for electrochemical processes
    • C02F2201/461—Electrolysis apparatus
    • C02F2201/46105—Details relating to the electrolytic devices
    • C02F2201/4616—Power supply
    • C02F2201/4617—DC only

Definitions

  • the present invention relates to an apparatus and method for the treatment of liquid.
  • One embodiment of the invention provides a water treatment system that occupies a small footprint and has low maintenance and running costs.
  • US 6998031 discloses a water treatment system, comprising two elongate tubular bodied electrodes, made of substoichiometric oxides of titanium
  • Ebonex® electrodes is advantageous due to their stability and long life, the system described in US'031 cannot easily scale to the throughput required for commercial use.
  • the present invention therefore aims to provide an alternative configuration for treating waste liquid using electrodes made from substoichiometric oxides of titanium that readily scales for commercial use.
  • the invention provides a liquid treatment apparatus comprising: a housing having an inlet and an outlet for the liquid; a flow channel extending between the inlet and the outlet and defining a flow path along which liquid can flow; a two dimensional array of non-coaxial electrodes at least some of which are made of substoichiometric oxides of titanium and which extend substantially parallel to each other across said flow channel in a direction transverse to said flow path; and connectors for electrically connecting each of the electrodes to one of the first and second electrical power terminals; wherein the connectors are arranged so that adjacent electrodes in the two dimensional array are connected to different ones of the first and second terminals. All the electrodes in the array are preferably made of substoichiometric oxides of titanium, although one or more of the electrodes may be made of more conventional electrode material, such as graphite, if desired.
  • the electrodes are arranged in a plurality of rows and connected so that adjacent electrodes in the same row are connected to different ones of said terminals. Adjacent rows of electrodes are preferably staggered from each other in an hexagonal packing arrangement in which the minimum spacing between neighbouring electrodes in the array is about 2mm.
  • the array of electrodes spans substantially across the whole of the flow conduit, so that the substantial majority of said fluid is constrained to flow through gaps between adjacent electrodes.
  • a plurality of the electrodes are tubular and the connectors to said tubes each include a sub-connector that extends along and makes contact with the inside surface of the tube at a plurality of spaced apart locations along the length of the tube. This arrangement allows for a more uniform distribution of charge along the length of the electrode.
  • the array of electrodes is preferably carried by an electrode frame that is detachably mounted within a mounting bay of the housing. This arrangement facilitates maintenance (for example to replace faulty electrodes) as the frame can be removed easily from the housing.
  • the apparatus preferably includes a plurality of electrode arrays (which may or may not be identical) arranged along the flow channel.
  • the elongate electrodes in one or more of the arrays may have a generally circular, square or polygonal cross-section in a direction transverse to its axis. Electrodes in the same array preferably, although not necessarily, have the same cross-section.
  • the housing is arranged so that, in use, the fluid to be treated is forced along a substantially vertical flow path between the inlet and the outlet.
  • a switch is provided for switching the electric potential applied to the electrodes, so that electrodes connected to the first terminal become connected to the second terminal and so that electrodes connected to the second terminal become connected to the first terminal.
  • Figure 1 shows a water treatment unit according to one embodiment of the invention
  • Figure 2 is a cross-section of the water treatment unit shown in Figure 1 along the xx axis;
  • Figure 3 is a cross-section of the water treatment unit of Figure 1 , along the yy axis and viewed from the front;
  • Figure 4 schematically illustrates an electrode drawer that forms part of the water treatment unit shown in Figure 1 ;
  • Figure 5 is a longitudinal cross-section of one of the elongate rod electrodes that is held in the electrode drawer shown in Figure 4;
  • Figure 6 illustrates the way in which the rod electrodes in one array are arranged in an hexagonal packing arrangement and connected to positive and negative terminals of a power supply;
  • Figure 7 illustrates an alternative arrangement of electrodes having a square cross-section
  • Figure 8 illustrates an alternative arrangement of electrodes having an hexagonal cross-section.
  • Figures 1 to 3 show a water treatment unit 1 , comprising, in this embodiment, an upright elongate housing 3, affixed, in use, to the ground by a base-plate 5, and having three main pipe connectors: an inlet 7, for untreated water, located at the front 8 of the unit, near the base plate 5; an outlet 9, for treated water, at the rear 10 of the unit, near the top 11 of the housing 3; and a drain 13, also at the rear 10 of the unit, near the base plate 5.
  • a gas vent 15 is located at the top 11 of the housing 3, towards the rear 10.
  • the housing 3 has dimensions of 1900 mm x 150 mm x 400 mm (height x width x depth) and is made from stainless steel.
  • the flow into the inlet 7 is pumped whereas the flow from the outlet 9 is gravity driven, therefore the diameter of the outlet 9 has been made larger than both that of the inlet 7 and that of the drain 13, in order to prevent the system backing up and overflowing via the gas vent 15.
  • the unit 1 has a shipping (i.e. non-operational or dry) weight of approximately 140 kg.
  • the housing 3 defines an elongate flow channel 17, which is substantially rectangular in cross-section, and which extends between and directs the flow of water from the inlet 7 to the outlet 9, the drain 13 being closed during normal use.
  • the housing 3 has six bays 19-1 to 19-6, accessible from the front 8 of the housing 3, and arranged in a linear sequence one after the other along the flow channel 17.
  • Each bay 19 is designed to receive and hold an electrode drawer 21 that is shown in cross- section in Figures 2 and 3 and in perspective in Figure 4.
  • FIG 4 is a perspective view of one of the electrode drawers 21 that forms part of the water treatment unit 1.
  • all the electrode drawers 21 are the same and each comprises a frame assembly 23, fronted by an inspection window 25 made of glass or Perspex®, that is designed to hold a plurality of rod electrodes 27 orientated substantially parallel to each other and arranged in a two-dimensional array 28.
  • each electrode drawer 21 is arranged to hold twenty five rod electrodes 27 arranged in successive horizontal rows of 4-3-4-3-4-3-4 rods, with the electrodes in adjacent rows being staggered relative to each other, as shown in Figure 4, so as to form the two-dimensional array 28.
  • the electrode drawers 21 and the corresponding bays 19 are arranged such that when the electrode drawer 21 is inserted into a bay 19, the longitudinal axis of each rod electrode 27 is transverse to the flow channel 17 (and therefore, during use, will be transverse to the flow of water passing from the inlet 7 to the outlet 9).
  • the rod electrodes 27 extend across the depth of the flow channel 17, between the front 8 of the housing 3 and the rear 10 of the housing 3.
  • the side walls 29 and 31 of the housing 3 in each bay 19 are shaped so that when the electrode drawer 21 is inserted into the bay 19, there is a close fit between the side walls 29 and 31 and the outer rod electrodes 27 in the array 28.
  • the closest separation between immediately adjacent electrode surfaces is 2 mm.
  • a small separation between adjacent electrodes means that a smaller voltage differential is required to be applied between adjacent electrodes 27 in the array to achieve a given electric field strength in the gap between adjacent electrodes 27.
  • the applied voltage is less likely to damage the rod electrodes 27 whilst also minimising the power consumption of the unit 1.
  • the water treatment unit 1 has six bays 19 each of which is arranged to receive and hold an electrode drawer 21 containing twenty five rod electrodes 27, for a total of one hundred and fifty electrodes 27 per unit.
  • Watertight blanking plates 32 are provided to seal empty bays 19, such as bays 19-1 and 19-6 in Figures 1 to 3.
  • FIG. 5 is a cross-sectional view of one of the rod electrodes 27 showing its construction.
  • each rod electrode 27 is made from an elongate hollow tube 35 of Ebonex® (the common and commercial name for a conducting ceramic made from substoichiometric oxides of titanium known as Magneli phases).
  • Ebonex® tubes 35 are produced according to the method disclosed in the applicant's co-pending British patent application 0618961.7, the contents of which are incorporated herein by reference.
  • the design of the electrodes 27 is in accordance with the electrode design described in US 6998031 , which discloses how an electrical contact is made to the tube by means of a titanium coil 39 that runs along the inside of the tube 35 along its length so that it contacts the inside surface of the tube at a plurality of spaces apart points along its length. This allows a more uniform charge distribution along the length of the electrode.
  • the advantages of using Ebonex® material for the electrodes 27 include a high resistance to corrosion and the ability of each rod electrode to function either as an anode or as a cathode.
  • the Ebonex® tubes 35 are 316 mm in length, with an external diameter of 18 mm and an internal diameter of 12 mm.
  • a plastic cap 41 , 43 At each end of the tube 35 is a plastic cap 41 , 43 and affixed between these end caps is a plastic rod 45 which runs lengthways along the axis of the titanium coil 39.
  • One of the end caps 41 has an electrical contact 47 for making a connection to the titanium coil 39. Electrical Connection
  • each rod electrode 27 in each array 28 are held at predetermined potentials by means of an external power supply 49 (shown in Figure 1), which can be regulated by a controller (not shown).
  • each rod electrode 27 is held at one of two potentials Vi or V 2 , where Vi > V 2 , according to the arrangement as shown in Figure 6, where for clarity Vi has been shown as a positive potential ('+') and V 2 as a negative potential ('-').
  • the difference between V 1 and V 2 is 6 volts and as the electrodes all have the same construction, this results in each rod drawing a constant DC current of approximately 0.5 to 1.4 amps.
  • the unit 1 therefore will have a maximum total power consumption of less than 1 kW.
  • untreated liquid in this case water
  • water is pumped into the inlet 7 and flows upwards along the flow channel 17 through the electrode arrays 28.
  • the water passes through the electrode arrays 28, it passes through electric fields produced between adjacent charged electrodes 27.
  • microscopic parasites such as Cryptosporidium and bacterium such as legionella pneumophila, the cause of legionnaires' disease, are destroyed by free radicals formed at the electrodes which interfere with and significantly damage the cell walls of the microorganisms. In addition, there may be some precipitation of dissolved solids.
  • Electro-coagulation is commonly used to separate suspended solids from contaminated water. It works by neutralising electrostatic charges carried on the surfaces of the suspended solids, which prevent them colliding and sticking together to form larger particles which would eventually settle.
  • Common electro-coagulation processes accomplish this using a sacrificial anode that corrodes and dissolves into the solution, thereby releasing charged particles (e.g. iron hydroxide) onto which the smaller suspended solids absorb.
  • a non-sacrificial electro-coagulation process is carried out using Ebonex anodes, which do not corrode and dissolve into the solution. Instead they achieve electro-coagulation solely by means of the electric field that is formed between the anodes and the cathodes, which causes the larger particles in the solution to become charged and thereby act as coagulants for the smaller particles.
  • the water then exits as treated water via the outlet 9 at the top of the unit 1.
  • the water output from the outlet 9 is typically filtered to remove the coagulated particles.
  • the increased size of the contaminant particles due to the electro-coagulation process means that effective filtration is more readily accomplished.
  • gaseous by-products for example hydrogen
  • gas vent 15 gaseous by-products
  • the unit 1 is designed to run at a substantially constant flow rate of between approximately 5 m 3 /hour and 10 m 3 /hour, with water taking approximately one minute to pass from the inlet 7 to the outlet 9.
  • the applicant has found that the present invention is effective at reducing the Chemical Oxygen Demand (COD) of untreated water by over 99% and likewise the Total Suspended Solids (TSS) by over 99%. It has also been shown to significantly reduce other contaminants such as chlorides, ammonia and heavy metals.
  • COD Chemical Oxygen Demand
  • TSS Total Suspended Solids
  • the unit 1 will require cleaning of deposited contaminants. This may be achieved by flushing the unit with fresh water and/or by reversing the current polarity applied to each electrode in the arrays 28 every hour. Polarity reversal is done to counteract the adsorption of ions onto the electrode surfaces. These ions, when so adsorbed, form deposits which reduce the effective electrode area and thereby increase the voltage difference and therefore the power required to maintain the working of the unit 1.
  • This ability to self-clean in particular without having to disassemble the unit 1 in particular offers a significant advantage over the co-axial two-component systems of the prior art which must be disassembled to perform routine maintenance tasks.
  • an electronic controller is provided for controlling this polarity switching. This allows the polarity switching in one of three ways:
  • a timing circuit configured to switch polarities at frequencies as high as 10Hz, but typically configured to switch polarities once every 2 to 5 minutes.
  • a current threshold switch which causes the polarity to be switched if the current applied to the electrodes drops below a predefined threshold value.
  • AC current may be applied, which will avoid the need for a separate polarity switching module.
  • the arrangement of the separate arrays 28 of electrodes in the bays 19 also facilitates maintenance as it becomes easy to remove and replace electrodes when they become faulty.
  • the unit 1 can be operated as normal. Therefore the "down" time for maintenance can be significantly reduced.
  • the rod electrodes 27 have a circular cross-section and therefore the electric field they produce is non-uniform.
  • the rod electrodes 27 can have a rectangular cross-section (as illustrated in Figure 7), resulting in a uniform electric field wherever the faces of adjacent electrodes are parallel.
  • the electrodes may have a polygonal cross-section, as illustrated in Figure 8.
  • the rods in each array 28 preferably have the same cross-section, although this is not essential. Rods in different arrays or even in the same array may have different cross- sections.
  • the electrodes in the same or different arrays may also have different dimensions. This may allow, for example, more control over the maximum spacing between neighbouring electrodes in each array (which in turn may allow lower voltages to be applied across the electrodes to achieve a desired field strength in the gap between adjacent electrodes).
  • the closest separation between immediately adjacent electrode surfaces is 2 mm. While there is no maximum separation above which the system could not work, the larger the separation between electrodes the larger the voltage required to achieve the desired field strength in the gap between adjacent electrodes. In practice, the maximum separation is therefore preferably less than 75 mm. Conversely, the minimum separation needs to take account of the risk of blockage by contaminant particles, and is therefore preferably no less than 1 mm.
  • the water treatment unit 1 was shown with four of the six bays 19 in use. As those skilled in the art will appreciate, any number of the six bays 19 can be used. More or less than six bays may also be provided.
  • the modularity of the unit 1 applies equally to other embodiments, wherein the size of the electrode array 28 can be altered according to the specific requirements of the treatment process.
  • the water treatment unit 1 is arranged so that the flow channel 17 is vertical.
  • the flow channel may be horizontal (to aid plug flow) or at any other intermediate orientation.
  • the flow channel 17 need not be linear and may follow a curved path.
  • the electrodes 27 were elongate rods, each of which spanned the width of the flow channel 17, and which were arranged in a two-dimensional array.
  • Alternative embodiments may comprise differently- shaped electrodes arranged in arrays of one, two or three dimensions, for example: • two sets of half-width rod electrodes arranged as two intermeshed two- dimensional arrays;
  • the electrodes were made of Ebonex. In an alternative embodiment, the electrodes may be made of other materials such as graphite.
  • a plurality of arrays of electrodes were arranged parallel to one another along a flow path.
  • the different arrays may have different orientations relative to the other arrays. For example, some arrays may extend from the front to the back of the housing whilst others may extend from one side to the other.
  • the polarity of the electrodes was reversed every hour.
  • Alternative embodiments may involve different polarity reversal schedules, for example a reverse polarity applied for two minutes every four hours.
  • each of the rod electrodes 27 was connected to one of two terminals and was thereby held at one of two potentials ⁇ or V 2 , where Vi > V 2 , according to the arrangement as shown in Figure 6, where for clarity Vi was shown as a positive potential ('+') and V 2 as a negative potential ('-').
  • adjacent electrodes in the same row were connected to the same terminal and were thereby held at the same potential e.g. + + + +.
  • Alternative embodiments may involve different arrangements of connectors.
  • adjacent electrodes in the same row may be connected to different terminals and thereby be held at different potentials such that each row comprises an alternating sequence e.g. + - + -.
  • the difference between potentials Vi and V 2 was 6 volts. In other embodiments other potential differences may be used, such as 24 volts. The potential difference used for a given situation will depend on the application to which the treatment system is being used.
  • the water was pumped into the inlet 7 and gravity fed from the outlet 9.
  • the water to be treated may be pumped into and out of the unit 1. This can allow better control over the flow rate of the water through the unit 1.
  • the pumps can be controlled by means of three level sensors positioned near the outlet 9 - an upper level sensor positioned above the outlet 9, a middle level sensor positioned at the top of the outlet 9 and a lower level sensor positioned at the bottom of the outlet.
  • the input pump may be turned on whilst the output pump is switched off. When the water level reaches the level of the middle level sensor, the output pump is switched on.
  • the flow rate of the water to be treated can be controlled by varying the speed of the inlet and outlet pumps. Additionally, by pumping the water from the outlet into a retention tank, a delay can be introduced after the treatment to allow for the effects of the treatment to be completed, before the water is then pumped through a separate filter.
  • each electrode drawer 21 carried twenty five electrodes 27.
  • the drawers may be arranged to carry different numbers of electrodes. For example, one or more of the electrode drawers 21 may be arranged to carry thirty two electrodes 27 - in eight rows of four electrodes 27.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Water Treatment By Electricity Or Magnetism (AREA)

Abstract

La présente invention concerne un système de traitement de liquide (1). Le système comprend un boîtier (3) ayant une entrée (7) et une sortie (9). Un conduit d'écoulement est disposé entre l'entrée (7) et la sortie (9) et un réseau d'électrodes est prévu, lequel s'étend à travers le conduit d'écoulement. Les électrodes sont connectées à des bornes d'alimentation électrique de telle sorte que des électrodes adjacentes dans le réseau sont des anodes et des cathodes. Dans un mode de réalisation, les électrodes sont montées dans des tiroirs qui peuvent être introduits et retirés du boîtier pour faciliter l'entretien.
EP07824637A 2006-11-21 2007-11-20 Système de traitement de liquide Withdrawn EP2125631A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0623204.5A GB2444056B (en) 2006-11-21 2006-11-21 Liquid treatment system
PCT/GB2007/004423 WO2008062170A1 (fr) 2006-11-21 2007-11-20 Système de traitement de liquide

Publications (1)

Publication Number Publication Date
EP2125631A1 true EP2125631A1 (fr) 2009-12-02

Family

ID=37636252

Family Applications (1)

Application Number Title Priority Date Filing Date
EP07824637A Withdrawn EP2125631A1 (fr) 2006-11-21 2007-11-20 Système de traitement de liquide

Country Status (3)

Country Link
EP (1) EP2125631A1 (fr)
GB (1) GB2444056B (fr)
WO (1) WO2008062170A1 (fr)

Families Citing this family (1)

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Publication number Priority date Publication date Assignee Title
US11396463B2 (en) 2016-11-10 2022-07-26 The University Of Massachusetts Method for electrochemical treatment of water

Family Cites Families (9)

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Publication number Priority date Publication date Assignee Title
GB191028277A (en) * 1910-12-05 1911-08-31 Electrolytic Apparatus Syndica Improvements in Apparatus for Producing Bleaching Solution.
GB1506402A (en) * 1974-05-24 1978-04-05 Nishizawa K Electrochemical cell
JPS52139678A (en) * 1976-05-18 1977-11-21 Kobe Steel Ltd Electrolytic cell
JPS5499340A (en) * 1977-09-21 1979-08-06 Inst Biomedizinische Technik Method and device for pasteurizing fluid by anodic oxidation
US5643884A (en) * 1993-08-09 1997-07-01 Glycomed Incorporated Lupane triterpenoid derivatives
US6315886B1 (en) * 1998-12-07 2001-11-13 The Electrosynthesis Company, Inc. Electrolytic apparatus and methods for purification of aqueous solutions
US6998031B1 (en) * 1999-07-01 2006-02-14 Atraverda Limited Electrode
DE10138625A1 (de) * 2001-08-13 2003-03-06 Sasserath & Co Kg H Gerät zur elektrophysikalischen Wasserbehandlung
DE102004018328B4 (de) * 2004-04-13 2007-11-08 Hochschule Niederrhein Volumenhaftes Elektrodensystem, dessen Verwendung und Verfahren zur Behandlung von fluiden Medien

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2008062170A1 *

Also Published As

Publication number Publication date
GB2444056B (en) 2012-07-04
GB0623204D0 (en) 2007-01-03
WO2008062170A1 (fr) 2008-05-29
GB2444056A (en) 2008-05-28

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