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
  • C02F1/30—Treatment of water, waste water, or sewage by irradiation
  • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
  • C02F1/325—Irradiation devices or lamp constructions
• • 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
  • C02F1/30—Treatment of water, waste water, or sewage by irradiation
  • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
• • 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
  • C02F1/467—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
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
• • 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
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/008—Originating from marine vessels, ships and boats, e.g. bilge water or ballast water
• • 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
  • C02F2201/32—Details relating to UV-irradiation devices
  • C02F2201/322—Lamp arrangement
  • C02F2201/3228—Units having reflectors, e.g. coatings, baffles, plates, mirrors
• • 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
  • C02F2201/32—Details relating to UV-irradiation devices
  • C02F2201/328—Having flow diverters (baffles)
• • 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
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2303/00—Specific treatment goals
  • C02F2303/04—Disinfection
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2305/00—Use of specific compounds during water treatment
  • C02F2305/02—Specific form of oxidant
  • C02F2305/023—Reactive oxygen species, singlet oxygen, OH radical
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2305/00—Use of specific compounds during water treatment
  • C02F2305/10—Photocatalysts

Definitions

• the present invention relates to a method for treating liquids, and in particular purifying liquids in order to remove or destroy harmful organisms in the liquid with photo-catalytic reactions.
• ballast water handling The biological balance in the seas has also been affected by man due to ballast water handling.
• Ships are arranged with ballast water tanks that are filled in order to stabilize them when the ships are not fully loaded with cargo. It is well known that ballast water contains species that have been recognised as major ecological problem if spread are cholera, kelp, toxic algae and mussels, just to mention a few. It is estimated that about 3-5 billion tonnes of ballast water are transported around the world. It is thus not surprising that this has become a major issue where the International Maritime Organisation of UN has issued a convention that with start from 2009 will put demand on all commercial ships to be equipped with and use special systems for handling ballast water.
• Another method is to radiate the created ozone with UV light of certain wave lengths in order to break down the ozone and create radicals, which are more aggressive than ozone.
• Such a method is disclosed in EP 0 800 407, in which the medium which is to be treated is introduced into some form of enclosure. In the enclosure, the medium is exposed to UV radiation with a spectral distribution within the range of 130 - 400 nm.
• the wavelengths below 200 nm convert the oxygen in the medium to ozone molecules (O3).
• the ozone molecules formed are at the same time decomposed by radiation within the above-mentioned wavelength range, especially at wavelengths of - 400 nm.
• the O2 formed is broken down to form atomic oxygen.
• catalysts are utilized, arranged in the zone where the ozone is decomposed to free radicals.
• the aim of the present invention is to further enhance the treatment capabilities and properties of photo-catalytic purification.
• a device for treating water comprising an enclosure having UV radiating means, and catalysts comprising a number of plates arranged in stacks with a certain distance between them and generally parallel to each other, characterised in that it further comprises an electric DC power source connectable to said catalysts such that every second plate of the stack is connected to the plus side of the power source and every second plate of the stack is connected to the minus side of the power source.
• the DC power source is capable of providing a voltage in the range of -5 - +5.
• the DC power source is capable of providing a current in the region of 1 mA - 1 A.
• the catalysts comprise metal, metal oxides or both, such as noble metals, aluminium oxide, titanium oxide, silicon oxide and mixtures thereof.
• said UV generating means comprises UV lamps, that said UV lamps are arranged in elongated UV permeable tubes, and that said tubes are arranged generally transversal to the direction of flow of the liquid.
• the present invention has a number of advantages in comparison with the known devices in this technical area.
• the properties of the process are improved in situ for: - the activation of ozone to reactive radicals, conversion of the ozonide anion ( O 3 " ) to ozone, conversion of ozone to the ozonide anion ( O 3 " ),
• the UV radiation emitted from the UV radiation generating means is used to a much higher degree than if some of the UV radiation is absorbed, which thus leads to a more efficient treatment process. Also, the required power is reduced.
• the inner surfaces could be covered by suitable materials, that have reflection increasing properties.
• the materials also have properties to withstand the tough conditions inside the treatment unit and the aggressive effects from the liquid to be treated.
• the materials should also be effective against scaling, which otherwise would reduce the reflection effect during use.
• Fig. 1 shows schematically one feasible embodiment of a treatment unit utilizing the present invention
• Fig. 2 shows an example of design of a stack of catalytic plates comprised in the present invention
• Fig. 3 shows another example of design of catalytic plates
• Fig. 4 shows yet an example of a stack of catalytic plates of a certain shape.
• a purifier that could use the present comprises a housing 20, in the shown embodiment as a generally elongated enclosure with a rectangular cross-section and with in- and outlets 22, 24 at each end of the enclosure.
• a number of UV radiating light sources 26 are arranged in elongated tubes of quartz glass 28, which extend between the opposite walls of the enclosure.
• the light sources are connected to suitable power supply.
• the UV radiating light sources are chosen such that they emit wave lengths in the region of 130 - 400 nm for converting oxygen in the medium to ozone molecules (O3) and for decomposing the ozone molecules.
• a number of plates 30, at least two, are arranged in the enclosure, the extension of which generally coincide with the direction of flow and thus perpendicular to the extension of the lamps.
• the plates are arranged in stacks with a certain distance between them.
• the plates act as catalysts for the treatment process thus boosting the amount of radicals produced.
• the plates are thus made of a material with catalytic properties to increase the number of radicals produced in the reactive zones.
• the material could include metal and/or metal oxides, such as noble metals, aluminium oxide, titanium oxide, silicon oxide and mixtures thereof.
• the plates of the stacks are connected to a DC-power source 36 such that every other plate in a stack is connected to the positive connection of the power source and every second plate is connected to the negative connection of the power source, Fig. 2.
• a suitable voltage is applied, which could be in the range -5 - +5 V and with a suitable current, which could be in the range 1 mA - 1 A.
• the number of plates and the distance between them are chosen such that an optimization is obtained regarding e.g. transportation of light from the lamps to the active surfaces of the plates; transportation of organisms in the vicinity of the surfaces; and transportation of free radicals from the surfaces into the liquid volume.
• the glass tubes are arranged substantially perpendicular to the direction of flow.
• the lamps are arranged in two rows, but there could be only one row as well, or more than 2 rows depending on the energy demands.
• the catalyst plates are preferably designed to increase and/ or promote the turbulence in the reactive zones as well as designed to increase the surface area.
• the catalyst plates 30 are made of expanded metal, thus creating a number of perforations or holes 34 through the plates.
• One advantage with expanded metal is that the edges of the holes are sharp, thus increases the turbulence.
• Other types of designs could be punching, structure pressings, corrugations, grooves and the like. It is also conceivable to use nets, woven or non-woven fabrics, wire mesh and the like. These could further be made in light permeable material such as quartz glass, glass fibre or other materials having the right properties.
• the design of the surfaces of the plates and/ or structure of the plates ensure that the boundary layer becomes very thin, which otherwise would prevent fluid exchange adjacent the photo catalytic surfaces of the plates, creating flow dead zones close to the surface where the radicals are the most potent.
• Other ways of decreasing the boundary layer could be to increase the surface rawness of the catalysts, by for example applying quartz sand to the surfaces.
• Fig. 5 shows an embodiment where, in contrast to Fig. 2, the plates do not extend all through the enclosure but are
• the plates could have a cross-sectional design where the leading edge of each plate, i.e. facing the flow, is sharp, and where the trailing edge is blunt, Fig. 6.
• the interior surfaces of the enclosure may be arranged with reflection enhancing means. Either selected parts of the interior surfaces are provided with reflection enhancing means or all inner surfaces.
• the reflection enhancing means provides a "reuse" of the UV light that is emitted from the lamps. This provides the effect that there is a much better effect in that light that hits the interior of the treatment unit is reflected and continues to treat the liquid. There is thus no absorption of light, whereby the power required for the UV lamps is reduced.
• reflection enhancing means There are a number of materials that might be suitable as reflection enhancing means. One important factor is that the material has to be able to withstand the rather aggressive conditions inside the unit, such as corrosion resistant properties and the like.
• PTFE polytetrafluoro ethylene
• PTFE polytetrafluoro ethylene
• PTFE has very high reflection capabilities and is thus suitable as a reflection enhancing material.
• PTFE displays very low friction coefficient and is also resistant against aggressive liquids such as seawater. This will reduce or even eliminate the scaling and will also reduce the hydraulic friction trough the treatment unit.
• other polymeric materials displaying similar properties can be used instead of PTFE.
• Polymeric materials are also much cheaper than steel or other metals.
• the polymeric material could be prepared with catalytic material in for example powder form dispersed in the polymer, such as for example metal and/ or metal oxides, such as noble metals, aluminium oxide, titanium oxide, silicon oxide and mixtures thereof.

Landscapes

• Chemical & Material Sciences (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Toxicology (AREA)
• Health & Medical Sciences (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Physical Water Treatments (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)
• Catalysts (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=42225926

Family Applications (1)

Country Status (5)

Citations (4)

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• 2008
  • 2008-11-28 SE SE0850107A patent/SE533527C2/sv unknown
• 2009
  • 2009-11-27 EP EP09829412.7A patent/EP2356078A4/de not_active Withdrawn
  • 2009-11-27 KR KR1020117014947A patent/KR20110105786A/ko not_active Application Discontinuation
  • 2009-11-27 CN CN2009801556267A patent/CN102300816A/zh active Pending
  • 2009-11-27 WO PCT/SE2009/051345 patent/WO2010062253A1/en active Application Filing

Patent Citations (4)

Non-Patent Citations (1)

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