Patent Application
20110215049
The present invention relates to a filter element and a method for making the same, more particularly to a filter element of organic membrane bioreactor used for wastewater treatment and a method for making the same.
Membrane bioreactor comprises a biological reaction tank and a membrane separation unit, characterized in that the quality of treated water is attractive, the treated water could be recycled; it requires relatively small space, the environmental adaptation is high; it is highly automatic, and it is easy to operate. The application of the membrane bioreactor is continuously developing, municipal wastewater treatment projects with capacity of 10,000 t and 100,000 t have been constructed, the number of the membrane bioreactor is continuously increasing, and thousands of membrane bioreactor projects have been carried out in many countries and regions around the world.
The membrane material used in the membrane separation unit may be divided to organic membrane and inorganic membrane. Inorganic membrane mainly includes metallic membrane, alloy membrane, haydite membrane, glass membrane, zeolite membrane and molecular sieve membrane, etc. Inorganic membrane possesses a number of advantages such as high chemical stability, acid/alkali resistance, organic solvent resistance; high mechanical strength, long lifetime; it could be back washed; inorganic membrane has high antimicrobial capacity, it does not react with micro-organism; it is highly thermal stable; the pore size distribution is narrow, and the separation efficiency is high. At present, the commercialized inorganic membrane is mainly haydite membrane which is in form of plate, tube or multi-channel. However, the process of inorganic haydite membrane is rather complex, it is difficult to process and thus the price is high, the cost is around 4000˜10,000 RMB/m2, furthermore, during filtration of inorganic haydite membrane, relatively high circulation flow is required between the biological unit and the membrane unit, which requires circulation pump with a relatively high power, as a result, the operation cost of the inorganic haydite membrane is relatively high. Therefore, its application is mainly limited to oil-water separation or recovery of certain chemical raw materials, for instance, recovery of titanium oxide powder, removal of precipitated heavy metal during petrochemical wastewater treatment, and recovery of latex from latex wastewater. The application of haydite membrane in membrane bioreactor is still under laboratory study, the global sales of separation membrane was above 10 billion USD by 2004, but the market share of inorganic membrane was only 12%. Many of the well-known membrane bioreactors use organic membrane, and the related information of organic membrane bioreactor has been discussed in the following references (Guo Dalin, PALL Comparison of different membrane techniques. Tsing Hua University: Seminar of membrane techniques in water treatment, 2005: 228; The Purification Company (Norit). X-low recycling of wastewater, Tsing Hua University, China: International symposium of membrane technologies for water and wastewater treatment, 2005: 195: Zheng Xiang et. al. Technical and Economic Analysis of membrane bioreactor, water supply and sewerage, 28(3), 2002: 105˜108). Membrane bioreactor is normally made by coating organic filter membrane material on fabric or fiber tube, wherein organic membrane is generally made from petrochemical material or plastic, however, the strength of the fabric or fiber tube is relatively poor, therefore, the strength of the organic membrane bioreactor is low, membrane might break, especially breaks of membrane fiber is easy to occur on hollow fiber membrane, sometimes breaks of membrane fiber are observed in a few months after installation. Once membrane breaks, the quality of treated water becomes poor. When the quality of membrane influences the treatment performance, membrane element has to be replaced, in this case, the operation of waste water treatment system has to be stopped, the workload and cost of replacement are high, especially for relatively large scale membrane bioreactor, the replacement of membrane is more complex, and the impact of influence is more severe. Due to the fact that organic membrane is made from petrochemical products, the replacement of membrane means the consumption of a large amount of non-renewable petroleum, this problem will become more serious as petroleum shortage becomes more severe. Moreover, the replaced waste membrane part is difficult to treat, the resulting organic industrial waste leads to secondary environmental pollution and new environmental burden. Even if accidental damage of organic filter membrane is prevented, the economical and environmental problems involved in regular and periodic membrane replacement are huge, with the development in the application of membrane bioreactor, especially with the development in the application of large-scale municipal waste water treatment projects, the problem becomes more serious. Therefore, low membrane strength and short lifetime of organic membrane bioreactor have become key constraining factors and technical difficulties that prevent scale production and application of membrane bioreactor.
The present invention aims at providing a filter element, its manufacturing method and water treatment device containing the filter element, in order to solve problems involved in current waste water treatment, for instance, the strength of organic membrane is poor, the lifetime is short, the production cost of inorganic membrane is high and the operation energy consumption is high.
To realize the objectives, the present invention provides a filter element, comprising a water permeable support and an organic filter membrane, wherein the water permeable support has an organic material layer on its surface, the organic filter membrane is coated on the surface of the organic material layer and is combined with the organic material layer, and the organic filter membrane has a pore size of 0.0015 μm˜20 μm.
The water permeable support may contain an aggregate and an adhesive coated on the aggregate, wherein the aggregate may be quartz sand, haydite or glass microsphere.
The adhesive may be an organic adhesive, and the organic adhesive forms the organic material layer on the surface of the water permeable support; or the adhesive may be an inorganic adhesive, an organic material may be coated on the surface of the water permeable support to form the organic material layer; or the water permeable support may have two layers which adhere to each other, in which the adhesive of one layer may be an inorganic adhesive, the adhesive of the other layer may be an organic adhesive, and the organic adhesive forms the organic material layer on the surface of the water permeable support.
The major ingredient of the organic filter membrane may be an organic filter membrane material which may be one or more of polyvinylidene fluoride, polyvinyl pyrrolidone, polyethersulfone, cellulose acetate, sulfonated polysulfone, sulfonated polyethersulfone, polyimide, polyvinyl alcohol and polyacrylonotrile.
The organic filter membrane material may have a hydrophilic group which may be hydroxyl, lactam or sulphon.
The organic material layer may be prepared by mixing the organic filter membrane material with an organic solvent to form a 1%˜10% organic filter membrane solution, and coating the solution on the water permeable support.
The water permeable support may have a cavity therein and an outlet thereon, and the cavity is communicated with the outlet.
The number of the cavity may be one, and a support point may be provided in the cavity in order to reinforce the strength of the water permeable support.
The number of the cavities may be more than one, the cavities may be cylindrical and arranged paralleled along the water permeable support, a spacing wall may be provided between each two adjacent cavities in order to improve the strength of the water permeable support, and a respective outlet is located on the position corresponding to each cavity, or the cavities are communicated with each other and are together communicated with the outlet.
The water permeable support may have a water-collecting space at the side wall corresponding to the end surface of the cavities, and the cavities are communicated with each other at the water-collecting space; or pores are located on the spacing walls of the adjacent cavities, and the pores allow the cavities to be communicated with each other.
The water permeable support may be rectangular or cubic. Or, the water permeable support may have a wave structure, troughs on one side of the wavy structure are connected with corresponding peaks on another side facing the one side so that the cavities are formed.
The organic material layer may be an organic adhesive layer, the organic adhesive may be a hydrophilic resin adhesive which is one or more of epoxy, polyurethane and acrylic resin, wherein the side chain of the epoxy, polyurethane and acrylic resin may contain hydrophilic carboxylate, sulfonate, ammonium salt, hydroxyl, or the back bone contains non-ionic hydrophilic segment.
The organic solvent may be dimethyl acetamide, formamide, ethylene glycol or ethylene glycol phenyl ether.
The present invention also p vides a method for the manufacture of a filter element, including the following steps:
forming an organic material layer on the surface of a water permeable support; and
coating or spraying an organic filter membrane material on the surface of the organic material layer to form an organic filter membrane on the surface of organic material layer; or applying an organic filter membrane on the surface of the organic material layer;
wherein, the organic filter membrane has a pore size of 0.0015 μm˜20 μm.
The water permeable support may contain an aggregate and an adhesive coated on the aggregate.
The aggregate of the water permeable support may be quartz sand, haydite or glass microsphere.
The adhesive may be an organic adhesive, and the organic adhesive forms the organic material layer on the surface of the water permeable support; or the adhesive may be an inorganic adhesive, an organic material may be coated on the surface of the water permeable support to form the organic material layer; or the water permeable support may have two layers which adhere to each other, in which the adhesive of one layer may be an inorganic adhesive, the adhesive of the other layer may be an organic adhesive, and the organic adhesive forms the organic material layer on the surface of the water permeable support.
The method may further include the step of mixing the organic filter membrane material with an organic solvent to form a 1%˜10% organic filter membrane solution before coating or spraying the organic filter membrane material on the surface of the organic material layer.
The water permeable support may have a cavity therein and an outlet thereon, and the cavity is communicated with the outlet.
The present invention also provides a water treatment device, comprising a filter device which comprises the above filter element.
The effects of present invention includes: filter element and water treatment device of present invention solve and overcome disadvantages of current membrane bioreactor, for instance, the strength of organic membrane is poor, the life time is relatively short, traditional inorganic haydite membrane is used which results in high production cost, operation energy consumption and operation cost, according to the present invention membrane of membrane bioreactor of fully utilizes natural, cheap and environmentally friendly material, the life time of membrane bioreactor is considerably improved (longer than the longest lifetime of organic membrane bioreactor reported in the articles), as a result, the resulting membrane bioreactor can be used in water treatment, waste water treatment and waste water recycle technique that is more practical, much easier to popularize and apply.
The structure and material of filter element of present invention are further illustrated with reference to the drawings.
The main ingredient of the organic filter membrane is an organic filter membrane material, the organic filter membrane material may be a hydrophilic material, and the organic filter membrane material may have a hydrophilic group, such as hydroxyl, lactam or sulphone. More specifically, the organic filter membrane material may be one or more of polyvinylidene fluoride (PVDF), polyvinyl pyrrolidone (PVP), polyethersulfone (PES), cellulose acetate, sulfonated polysulfone, sulfonated polyethersulfone, polyamide, polyvinyl alcohol and polyacrylonotrile. Furthermore, the pore size of the organic filter membrane 2 is small, fine and homogeneous, the pore size of the organic filter membrane is 0.0015 μm˜20 μm. The pore size of the water permeable support 1 is between 50˜200 μm, and therefore irreversible membrane contamination could be effectively alleviated.
The organic material layer 3 may be an organic adhesive layer, the organic adhesive is hydrophilic resin adhesive, the hydrophilic resin adhesive may be one or more of epoxy, polyurethane and acrylic resin, the side chain of which may contain hydrophilic carboxylate, sulfonate, ammonium salt, hydroxyl or the back bone contains non-ionic hydrophilic segment.
The organic material layer 2 may be prepared by mixing the organic filter membrane material with an organic solvent to form a 1%˜10% organic filter membrane solution, and coating or spraying the solution on the water permeable support 1, such that the organic material layer 3 on the surface of the water permeable support 1 is covered with the organic material layer 2; or the organic material layer 2 may be prepared by directly coating an organic filter membrane on the surface of organic material layer 3. Wherein, the organic solvent may be dimethyl acetamide (DMAC), formamide, ethylene glycol or 2-phenoxyethanol.
Furthermore, the water permeable support contains aggregate and adhesive that covers the aggregate. The aggregate may be quartz sand, haydite or glass microsphere.
Furthermore, the adhesive may be an organic adhesive, and the organic adhesive forms the organic material layer on the surface of the water permeable support; or the adhesive may be an inorganic adhesive, an organic material may be coated or sprayed directly on the surface of the water permeable support to form the organic material layer; or the water permeable support may have two layers which adhere to each other, in which the adhesive of one layer may be an inorganic adhesive, the adhesive of the other layer may be an organic adhesive, and the organic adhesive forms the organic material layer on the surface of the water permeable support. Wherein, when the aggregate is covered by the organic adhesive, and organic filter membrane material is coated on the surface of the organic adhesive-formed organic material layer, the strength of the water permeable support is improved considerably.
Moreover, as shown in
Furthermore, the Figures are only examples of structure of filter element of present invention, the filter element of present invention is not limited to the specific structures, besides the structures above, the water permeable support may be other structure, for instance, sphere, ellipsoid so that demand on different appearance may be met.
The method for making filter element of present invention includes: water permeable support 1 is formed from quartz sand, haydite or glass microsphere with the aid of adhesive, and organic material layer 3 is formed on the surface of the water permeable support 1, during the step, when organic adhesive is applied, the organic adhesive forms the organic material layer on the surface of the water permeable support; when inorganic adhesive is applied, the organic material layer may be formed via coating, spraying or roll-coating of organic materials on the surface of the water permeable support, or the water permeable support has two layers, wherein adhesive of one layer is inorganic adhesive, adhesive of the other layer is organic adhesive, and the organic adhesive forms the organic material layer on the surface of the water permeable support. Furthermore, the method may includes: organic filter membrane is covered on the organic material layer via coating, spraying, roll-coating or directly applying, more specifically, the organic filter membrane may be coated, sprayed or roll-coated on the organic material layer, so that organic filter membrane is formed on the surface of the organic material layer, or organic filter membrane is applied on the surface of the organic material layer, so that the organic filter membrane is combined with the organic material layer, and the pore size of the organic filter membrane is 0.0015 μm˜20 μm. When aggregate covered by organic adhesive is applied, and organic filer membrane is formed on the surface of the organic material layer containing organic adhesive, the strength of the water permeable support is improved considerably.
Furthermore, the preferred organic material may be organic adhesive, the preferred organic adhesive may be hydrophilic resin adhesive, the hydrophilic resin adhesive is one or more of epoxy, polyurethane and acrylic resin, the chain of which contains hydrophilic carboxylate, sulfonate, ammonium salt, hydroxyl or the back bone contains non-ionic hydrophilic segment; moreover, the organic filter membrane is hydrophilic, the hydrophilic material may contain hydrophilic group, such as hydroxyl, lactam or sulphone, more specifically, the organic filter membrane is one or more of polyvinylidene fluoride, polyvinyl pyrrolidone, polyethersulfone, cellulose acetate, sulfonated polysulfone, sulfonated polyethersulfone, polyamide, polyvinyl alcohol and polyacrylonotrile, and the pore size of the organic filter membrane 2 is 0.0015 μm˜20 μm. Wherein, the application of organic filter membrane on the surface of the organic material layer 3 includes: the organic filter membrane is mixed with organic solvent to form 1%˜10% organic filer membrane solution, the membrane solution is coated, sprayed, or roll-coated on the water permeable support 1, so that the organic material layer 3 on the surface of the water permeable support 1 is covered with the organic filter membrane 2, wherein the organic solvent is dimethyl acetamide, formamide, ethylene glycol or 2-phenoxyethanol.
Furthermore, it may further include the following steps: a cavity is formed in the water permeable support, a support point 4 is formed in the cavity to improve the strength of the water permeable support 1, and outlet 5 is formed on the water permeable support 1 so that the cavity is communicated with the outlet. Wherein, organic material is directly coated, sprayed or roll-coated on the surface of the water permeable support 1 to form the organic material layer 3, and the organic filter membrane 2 is formed on the surface of the organic material layer 3.
The water permeable support may also be other structure, as shown in
Furthermore, the filter element of present invention may be used in filter device of different water treatment device (for instance, water treatment device, water purification device or system for lake, river, municipal water, agricultural water), that is, the filter device of the water treatment device may contain one or more filter elements of present invention, waste water treatment, waste water regeneration and water purification treatment are carried out with the aid of filter element of present invention, the utilization of filter element of present invention is in the protection scope of Claims of present invention.
The present invention may also contain other Examples, changes and modifications may be made by those skilled in the art based on present invention, however, the corresponding changes and modifications are in the protection scope of Claims of present invention.
In the filter element of present invention, water permeable support is combined with organic filter membrane, and organic material layer is formed on the surface of the water permeable support, so that organic filter membrane is covered on the surface of the water permeable support due to the firm combination between the organic filter membrane and organic material layer, because the strength of the water permeable support is high and the combination between the organic filter membrane and organic material layer is firm, problems involved in current membrane bioreactor, such as the strength of organic membrane is poor, the lifetime is short, the production cost, operation energy consumption and cost of traditional organic haydite membrane is high, are solved and overcome. As a result, irreversible membrane contamination is effectively alleviated, organic filter membrane of membrane bioreactor fully utilizes natural, cheap and environmentally friendly materials, hence, the life time of membrane bioreactor is prolonged which is much longer that the longest reported lift time of 5˜10 years, the resulting membrane bioreactor could be used in water treatment, waste water treatment and waste water recycle technique that is more practical, much easier to popularize and apply.
Compared with the price of traditional haydite membrane (4,000˜10,000 RMB/m2), the coated and sand-cast plate membrane is cheaper, the price is around 100˜300 RMB/m2, and cross-flow filtration is not required, and therefore, the energy consumption is low;
The present invention possesses a number of advantages, such as the water permeable rate is high, the strength is high, the life time is relatively long and it is acid-alkali resistant.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200810227443.9 | Nov 2008 | CN | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/CN2009/001275 | 11/17/2009 | WO | 00 | 3/23/2011 |
