Wastewater treatment, treatment for it and receive it

 

(57) Abstract:

The invention relates to granular dispersed material used in the installation and the methods of wastewater treatment, obtaining this material, as well as methods and devices for treatment of wastewater with the use of this material. The plastic granules contain put on them grain inert minerals such as sand, to obtain a habitat for microorganisms, is effective in the treatment of wastewater, and the granules have a specific range of grain size, and grain are specified range and are located on the granules with a given density. The particles have an average density of about 1.0 g/cm3so that part of them can swim, and some may sink in the wastewater. Particles obtained by contacting the granules of plastic with a mixture of grains of inert mineral and grain-soluble substances, such as salt, at an elevated temperature for coating pellets with this mixture, followed by dissolving the grains of soluble substances from the coating to obtain granules, coated granules of inert mineral with a specific density range seeding. Effect: reduced energy costs, simplifying operation obrazuemogo to install and methods of wastewater treatment, receiving this material, as well as methods and devices for treatment of wastewater with the use of this material.

Wastewater can be treated by gasification, for example by aeration or oxygenation of sewage or other waste water containing organic matter, decomposing when exposed to oxygen. Proposed and used a large number of methods and devices for processing. Oxygen does not dissolve quickly and easily in water, and therefore, in principle, it is desirable to use fine bubble aerators, in which the diameter of the bubbles is less than 2 mm, preferably less than 1 mm smaller bubbles have higher specific surface area for oxygen transfer into the liquid and, in addition, a slower rise in the liquid, thus there is more time to move oxygen before the bubble reaches the surface of the liquid. The known installation for processing, representing the capacity for processing and device for aeration, submerged in the waste water to produce bubbles.

It was also suggested that the treatment plant, where the capacity to handle contains a layer of granular material. Aeration leads to metastorage oxygen microorganisms convert organic matter of wastewater into carbon dioxide, water and more bulky cellulose materials and residue that reduces the biological oxygen demand (BOD). Under appropriate conditions, they also transform the ammonia into nitrates. Received additional precipitate can optionally pass with wastewater for potential separation and recycling.

Problems of pollution and contamination aerating installations and any pipeline can become acute if these pipelines cover or protect with a layer of granular material. Regular stop and drainage installations for cleaning or replacement aerators is inefficient and costly due to the need to separate or remove the material of the filter layer to gain access to the closed aerators.

In our application PCT/GB 94/02795 (publication WO/95/17351) described a method and apparatus for wastewater treatment, which partially solved these problems and, in particular, the bulk of the dispersed material for use as psevdoozhizhennogo layer at the wastewater treatment, this material differs in that it contains particles essentially inert mineral, attached, applied or coated with plastics that obespechivaetsya wastewater treatment, characterized in that the waste water fed into the tank to handle containing layer of the bulk of the dispersed material, and carry out the gasification of this layer and wastewater using gas bubbles emitted from one or more gasifiers inside layer and adapted to be placed in the specified water level and remove it.

In this application also describes a device for the treatment of wastewater, characterized by the presence of a tank for processing containing layer of the bulk of the dispersed material, one or more gasifiers, moving image located inside the layer, and means to supply gas to the gasifier to highlight it in the form of bubbles of gas for gasification layer and wastewater, the gasifiers are adapted to be placed in the water layer and to remove from it.

In this application describes such a bulk of the dispersed material with a density in the range being from 1.0 to 1.3 g/cm3with a specific surface area greater than about 6002per cubic meter of loose material, and with a particle size in the range being from 3 mm to 10 mm in diameter. The example of the material constituting the particles of sand or gravel or other plastic material, for example, polyethylene, applied or covered with them. It was shown that may be obtained from the material to the desired density for a particular application by changing the initial ratio of the mineral and plastic. Particles can be formed by partial melting of polyethylene, for example, hot air, and bringing it into contact with sand or gravel. When using particles are quite friable and easily allow the gasifiers passed through the layer and were located in the right place at the bottom of the tank. It does not require a protective case, mesh or lattice.

In practice, this bulk of the dispersed material was effective for use as psevdoozhizhennogo layer when processing wastewater using such methods and devices. It is established that such materials provide a particularly suitable environment for high-density populations of microorganisms of this type, which is effective in the treatment of wastewater.

However, it was found that particularly effective processing can be performed, if the physical characteristics of solids dispersed material precisely defined and regulated in accordance with the processing requirements on Dane method thereof.

In accordance with the invention proposed bulk of the dispersed material for use in wastewater treatment, this material is characterized by the presence of granules of plastic, each of which has many of the grains are essentially inert mineral drawn on it to get the environment for microorganisms, is effective in the treatment of wastewater, and the granules have a specified range of particle sizes, and grains have a specified range of particle sizes and are located on the granules with a given range of density packaging.

The bulk of the dispersed material can be considered as psevdoozhizhennogo layer. In practice, however, serious challenges such pseudoacademic layers showed that certain problems can occur, probably as a natural consequence reached high population density and, hence, the compactness of the installation for a given feed wastewater.

Thus, in accordance with another aspect of the invention proposed bulk of the dispersed material for use in wastewater treatment, this material is characterized by the presence of granules of plastic, each of which has many of the grains are essentially inert mA who ICEM granules have a specified particle size range, grains have a specified range of particle sizes and is distributed in the granules with the specified density range of packaging and loose particles dispersed material have an average density of about 1.0 g/cm3so that part of the particles can float in the treated wastewater, and some may sink.

Preferably the material has properties such that about 50% of the particles that can float on the surface of the processed mixture of wastewater, and about 50% of the particles may sink after the initial load and when the mass of wastewater is at rest. When conducting aeration established that particles very quickly mix in the strongly recirculating flow, requiring a minimum supply of energy and gives a highly efficient aeration.

The invention also proposed installation and methods for treatment of wastewater using granular dispersed materials.

In addition, in the invention, a method for receiving bulk dispersion of the material used for wastewater treatment, comprising the contacting of the granules of plastic material having a given range of particle sizes, with a mixture of grains essentially inert mineral with a specified range of the ur for coating granules of the mixture and subsequent dissolution of grains soluble substances from the coating to obtain granules, covered with grains of essentially inert mineral with a given range of density packaging.

We found that for effective and efficient wastewater treatment is required bulk of the dispersed material with a specified range of particle sizes, the relevant requirements of the data processing wastewater. It is governed by the particle size range of granules of plastic, usually 3 to 10 mm, viewing it as the range of sizes of sieves, having in mind, as a rule, uneven shape and received in the industry granules. The preferred range of sizes from 4 to 8 mm, more preferred from 4 to 6 mm Suitable source of such granules are available in industry secondary scrap plastic, preferably granulated from molten waste, such as plastic drawers.

In addition, it is usually necessary to get the bulk of the dispersed material with a high specific surface area, for example greater than about 600 m2per cubic meter. The higher the specific surface area is, the higher the area of habitat of microorganisms effective in water treatment. Note that a larger number of smaller mineral grains will provide more than the mineral, for example, from 0.1 to 3.5 mm, preferably from 0.1 to 2.5 mm, again depending on the processing requirements of a particular wastewater.

The density of the plastic is determined by the choice of plastic, preferably polyethylene, and is less than 1.0 g/cm3. Similarly, the density of a mineral is determined by the choice of the mineral, preferably sharp sand, and significantly greater than 1.0 g/cm3. Accordingly, the total bulk density of the dispersed material is inevitable due to the initial choice of the size of the plastic particles and mineral. The surface area of the granules of the plastic increases only in proportion to the square of its diameter, and its volume increases with the cube of its diameter. The thickness and, therefore, the effective volume of the mineral coating depends on the diameter of mineral grains on the surface of granules of plastic.

Therefore, the initial choice of the size ranges of the particles of this plastic and this mineral causes the density of the resulting particles to a specified value. This value may differ from the desired. In practice, if the density is significantly greater than 1.0 g/cm3then the particles during use can be to make plans in connection with the circulating flow of wastewater caused by the flow of bubbles from the aerator. In this regard, I believe that usually the density of wastewater is about 1.0 g/cm3. If the particle density less than 1.0 g/cm3then the particles you are using may not be desirable to concentrate in the form of a floating mass in the upper part of the tank for processing, and the desired circulation again will not be achieved.

Generally, for the efficient treatment of wastewater, it is desirable that most of the particles in fluidized bed heavily circulated in the circulating flow of wastewater caused by aeration. The objective of the invention is the provision of bulk dispersed material, having a density corresponding to the desired specified value, and, depending on the parameters of the treated wastewater and the processing plant, especially from its horizontal dimensions and depth of the water layer.

Thus, the invention allows to obtain the bulk of the dispersed material, which to some extent can be specified not only desirable ranges of particle sizes of the granules of plastic and they are on of mineral grains, but also the density of the final material. This is achieved when taking into account the possibility of the tx2">

Next will be described an embodiment of the invention using an example with reference to the drawings.

In Fig. 1 shows a cross section of particles of material having essentially uniform coating.

In Fig. 2 shows a cross section of particles with variable density of the coating.

In Fig. 3 shows a cross-section of a particle with another variable density of the coating.

In Fig. 1 reproduced in Fig. 3 of our above-mentioned patent WO/95/17351. It shows the pellet 80 polyethylene having a large number of grains 81 sharp sand, attached thereto as a coating by partial melting, so that the grain is partially embedded in the pellets.

In Fig. 2 shows a similar pellet 80 with a coating of grains of sharp sand with adjustable low density, so get the particle with the desired predetermined density, and Fig. 3 shows a similar pellet with adjustable lower density to obtain particles with a given lower density.

The particles shown in Fig. 2 and 3, can be obtained as follows. Choose the range of particle sizes of the granules of the angular end is on mineral for example, sharp sand, thoroughly mixed in a selected ratio, for example 50:50, with grains soluble substance having the specified particle size range. Soluble substance may be common salt, i.e. sodium chloride. The particle size of a regular table salt is approximately 0.15 mm, and the usual salt water softener is about 3.3 mm

The plastic granules are heated up until they begin to partially melt, i.e., the surface becomes shiny and sticky. Then they are brought into contact with mineral mixture, for example by rolling in the tray with the mixture. In this way, each granule is coated with adhering thereto a layer of the mixture. Then the granules coated washed with cold water, preferably while they are still warm. Soluble grain of salt dissolved in water, leaving behind granules, essentially having a floor entirely of grains of sharp sand. Then the wash water can be treated to remove dissolved salts and use for another purpose or recycling.

The dissolved substance may be any available from the economic point of view, granular substance that is soluble in the usual solvents, for example water is softening granules of polyethylene, i.e. above approximately 200oC.

The density can be adjusted by selecting the range of the particle size of grains of soluble substances in relation to the range of the particle size of grains of sand. In Fig. 2 shows the resulting particle, when the size ranges of the particles is essentially the same, for example, particles of each type size of about 0.25 mm to 8 mm plastic pellets. In Fig. 3 shows the resulting particle, when the grain of salt is about three times the diameter of the grains of sand, for example, for a grain of salt 0.5 mm and grains of sand 0,15 mm

In a preferred embodiment of the invention, the density adjust by changing the initial ratio of grains of sand and salt in the mixture and it will be shown that this has an effect similar to changing the ratio of the ranges of particle sizes. Thus, it is possible equivalent to assume that in Fig. 3 shows the resulting particle, when the initial mixture contains a grain of sand and salt is essentially the same size in a ratio of about 1: 3. As the initial value, and the relative grain size can be changed independently from each other. The advantage of the control density fill by using a grain of sand and salt sumariwalla getting thoroughly stirred mixture of grains of sand and salt.

Thus, the invention allows to obtain particles of the desired density for a particular processing method and the specific unit, as well as particles of the desired specific surface area, for example in the range from 300 to 600 m2/m3for specific processing method and the specific installation. It additionally provides the initial loading of the installation particles with gradually changing properties. For example, a fluidized bed can be obtained as a multilayer composite with a bulk dispersed material having a relatively high density in the lower part and a lower density in the upper part, and, probably, with an intermediate layer of intermediate density. When using more dense particles circulate mainly in the depth of the tank and carry out the primary, the most coarse aeration and some filtering, while the lighter particles, more intensively circulating mainly in the upper layers, complete aeration of wastewater. At different levels can develop a slightly different populations of microorganisms, which gives advantages in water treatment.

In another embodiment, the particles receive for a particular installation, so some frequent is when the waste water are at rest.

The authors unexpectedly found that the use of such light material, i.e. a material with low density have provided unexpected benefits. Not only the efficiency of the wastewater is maintained at a high level, but it is combined with the simplicity and convenience of use. I believe that this may be due to deviations from available technology trends to consider dispersed material as pseudovariety layer, implying therefore that the material should be deposited in a layer at the bottom of the reservoir water treatment after disconnecting aerators, and therefore, the particles must have a density higher than 1.0 g/cm3. This is at least partly a consequence of the fact that it was considered necessary to particle layer was performing a filtering function.

It is now established that the way to handle improve by maintaining the particles of the medium in constant motion inside and essentially through the mass of wastewater in the tank for processing, i.e., the particles should be above a density of about 1.0 g/cm3so that part of the particles can float, and part of it might sink in the wastewater, while a large number of them suspended in the mass. Rela is has a high efficiency of air contact, microorganisms and particles of their food in the treated wastewater. In addition, movable particles contribute to the transport of oxygen, hindering the movement of bubbles up to the surface. When the bubble collides with a particle, it is either broken down into smaller bubbles, or at least slows down when moving along the uneven surface of the particles.

It is established that the method gives a stable population of microorganisms, at any time located on the suspended particles, which is not too increases and not too reduced for a certain period of time when inevitably large fluctuations in the amount of sewage entering the tank for processing and flowing through it. This provides for a more long-term stability required plant operators, especially for "deserted" installations, facilitates and simplifies maintenance.

Since the average density of particles is almost equal to the density of the wastewater, i.e., they have neutral buoyancy, for aeration and circulation requires a minimum of energy. It is noted that when the flow of energy through the aerators not only is the aeration of the sewage, but also raises the flow circulation in reservable for effective use in this setup and processing methods, as described in this patent.

The processing efficiency is suspended and circulating microorganisms on the particle and energy efficiency allow to realize a very high load factor and, consequently, smaller plant size for a given load, it is combined with stability during operation, simplicity and ease of service.

Because of this efficiency tank for processing can be filled dispersed material only 20% of its volume in comparison with filling 60-80 vol.% some known in the art surround materials for processing.

Particles can be obtained by contacting the granules of plastic with a specified range of particle sizes with a mixture of grains essentially inert mineral with a specified range of particle sizes and grains soluble substances with a specified range of particle sizes (possibly the same as the inert minerals) at elevated temperature to provide coverage of the particle mixture, followed by dissolving the grains of soluble substances from the surface of the coating to obtain granules, coated granules essentially inert mineral with a specific density range Zap the sand for sandboxes, high content sufficiently close grain size.

Knowing the density of the plastic and inert mineral, you can easily determine the range of the distribution density to obtain the required average density of approximately 1.0 g/cm3.

In addition, the contact conditions of the granules and the mixture of grains, as well as high temperature probe can be installed in such a way that the grains are covered with granules, much delving into partially molten outer surface of the granules. Thus, approximately 50% of the volume of grain shipped in plastic, and the remaining 50% are above the surface, so that the grains are firmly held in their places on the pellets during their subsequent use for water treatment.

The authors also found that when these are shipped in plastic grains at a later stage of dissolution of grains soluble substances on the surface of the granules remain basin with a total surface area is comparable with the total area of the convex surface of the remaining grains of insoluble inert material. This allows to obtain important technical advantage in that the specific surface area of particles of the Ala and the number of grains of soluble substances.

Accordingly, the initial ratio of salt:sand can be selected within a wide range, for example from 1: 1 to 8:1 or even higher, without reducing the high values of specific surface area, for example, more than about 600 m2/m3as specified above.

It should be understood that a large number of smaller grains will provide higher specific surface area, but the advantage of using much immersed in plastic grains is that the grain size can be selected for a given specific surface area regardless of the choice of the ratio of salt:sand. Thus, the invention proposed bulk of the dispersed material, optimally tuned for the effective treatment of wastewater.

1. The bulk of the dispersed material for use in the treatment of wastewater, characterized by the presence of granules of plastic, each of which contains many grains of essentially inert mineral that is deposited to obtain a habitat for microorganisms, is effective in the treatment of wastewater, and the granules have a specified range of particle sizes, and grains have a specified range of particle sizes and are located on the granules with the specified density range sapoa of these loose particles dispersed material can float, and part of it might sink in the treated wastewater.

2. The bulk of the dispersed material under item 1, characterized in that approximately 50% of the particles can float near the surface of the mass of treated wastewater, and about 50% can sink after the initial load and when the mass of wastewater at rest.

3. The bulk of the dispersed material according to any one of paragraphs.1 and 2, characterized in that it has a specific surface area greater than about 600 m21 m3bulk material.

4. The bulk of the dispersed material according to any one of paragraphs.1 to 3, characterized in that it has a particle size range of bulk dispersed material essentially from 4 to 6 mm in diameter.

5. The bulk of the dispersed material according to any one of paragraphs.1 to 4, characterized in that the sand is attached to the granules of polyethylene.

6. The method of obtaining bulk dispersed material for use in the treatment of wastewater, comprising the contacting of the granules of plastic with a specified range of particle sizes with a mixture of grains essentially inert mineral with a specified range of particle sizes and grains soluble substances with a specified range of particle sizes at an elevated temperature for pokr is open grains essentially inert mineral with a given range of density fill.

7. The method according to p. 6, characterized in that the granules are subjected to contact with grains of essentially inert and mineral grains soluble substances essentially with the same ranges of grain size.

8. The method according to p. 6 or 7, characterized in that the mixture contains grains of essentially inert mineral and grain-soluble substances in a ratio of about 1 : 8.

9. The method according to any of paragraphs.6 to 8, characterized in that the granules are subjected to contact with the mixture at an elevated temperature so that the grains are covered with granules, substantially partially immersed in the molten outer surface of the granules, while at the stage of dissolution of grains soluble substances on the surface of the granules remain hollow.

Priorities on items and features:

13.02.1995 on PP.1, 3, 5 - 7;

17.11.95 Sign of paragraph 1 "of these loose particles dispersed material can swim, and some may sink in the treated wastewater and PP.8 and 9;

13.02.1996 on PP.2 and 4.

 

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FIELD: industrial organic synthesis.

SUBSTANCE: invention provides catalyst for production of methyl ethyl ketone via oxidation of n-butenes by oxygen and/or oxygen-containing gas, which catalyst is composed of aqueous solution of molybdeno-vanado-phosphoric heteropolyacid or mixture of the latter with its salt and 5·10-4 to 1·10-2 M palladium stabilized by phthalocyanine ligand at palladium-to-phthalocyanine molar ratio 0.5-2. Mo-V-phosphoric heteropolyacid is depicted by formula H19P3Mo18V7O84. concentration of vanadium being 0.4 to 2.2 g-atom/L. Oxidation of n-butenes is carried out continuously in two steps at temperature 15 to 90оС. Catalyst is regenerated in contact with oxygen or oxygen-containing gas at 140-190оС and oxygen pressure 1-10 gauge atm.

EFFECT: enhanced process efficiency due to increased stability of catalyst components.

7 cl, 1 dwg, 6 tbl, 7 ex

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