JP2003290604A - Recovery method for oils-and-fats component from wastewater and reutilization method for the component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently separating and recovering an oils-and-fats component such as scum or froth from wastewater containing that component, and a method for effectively reutilizing the recovered coils-and- fats component. <P>SOLUTION: An organic solvent is added to wastewater containing the oils- and-fats component to dissolve the component such as scum or froth and the component is further separated and recovered from the organic solvent such as hexane or the like in which the component is dissolved to efficiently separate the component from wastewater. The oils-and-fats component thus separated and recovered can be reutilized as fuel, fertilizer or the like. Besides, the organic solvent from which the oil-and-fats component is separated and recovered is recycled to be reutilized. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering and reusing oils and fats from wastewater, and more specifically,
The present invention relates to a method for effectively and efficiently separating and recovering such fats and oils from wastewater containing fats and oils such as scum and floss and reusing the separated fats and oils as fuel and the like. Further, the present invention relates to an oil and fat treatment apparatus and an oil and fat treatment method capable of efficiently and easily recovering the oil and fat content of waste water.

[0002]

2. Description of the Related Art Conventionally, most of the waste water from food processing plants, meat processing plants, pig farms, etc. has been treated as industrial waste by industrial dumping or incineration.
However, since it is no longer possible to dispose of such industrial waste by ocean dumping, most of it is currently incinerated. Even if such wastewater is incinerated, since the wastewater contains a very high water content of 80% or more, it is very inefficient to incinerate as it is, and a large amount of heavy oil, etc. It has a big problem of needing petroleum fuel. Therefore, the method of reducing the amount of industrial waste to be incinerated and incinerating it is usually adopted. As one of such methods, for example, waste water from a food processing factory or a meat processing factory is stored in a tank or the like, and naturally separated into oil and fat, intermediate water, and sludge to remove only intermediate water. Then, the method of incinerating the fats and oils and the sludge is used. Even by simply incinerating the oil and fat and sludge treated in this way, the petroleum fuel required for incineration can be greatly saved, the incineration time can be greatly shortened, and the amount of carbon dioxide generated can be significantly reduced. Can be However, as described above, the waste oil containing high oil and fat is separated from the oil and fat, the sludge and the intermediate water, and the residual oil and fat and sludge after removing the intermediate water still contain a large amount of water. Therefore, even when the oil and fat and the sludge are incinerated, the incineration efficiency is not so high, and the petroleum fuel required for the incineration cannot be significantly reduced. In addition, the intermediate water separated from the wastewater cannot be discharged without water treatment (biological treatment), so it is common to treat the intermediate water once in the aeration tank before discharging it. Further treatment of the intermediate water in the aeration tank also requires a large amount of treatment cost. In addition, there are some places where the intermediate water is heated to improve the separation of oils and fats, but if the intermediate water is placed in the aeration tank while it is still warm, the temperature of the intermediate water becomes too high. As a result, the microorganisms in the aeration tank are killed, and the biological treatment itself is not properly performed. In addition, at the wastewater treatment site where there is no storage tank for natural separation such as a tank, the current situation is to incinerate all highly hydrous industrial waste that still contains a large amount of water. In this way, it cannot be said that the current wastewater treatment has extremely poor treatment efficiency.

By the way, food processing plants and meat processing plants,
Waste water from pig farms contains a large amount of oil and fat in addition to water, and treating this oil and fat is a very troublesome problem. As described above, the method of separating the wastewater into the intermediate water, the oil / fat and the sludge, and recovering the oil / fat and the sludge and incinerating them is also one method, but this method has a sufficiently high treatment efficiency. However, the incineration requires a large amount of fuel. Therefore, in order to smoothly treat the oil and fat in the wastewater, a method of removing the oil and fat from the wastewater before the treatment is often used. As a method for that purpose, for example, an oil / water separation tank called a grease trap, a pressure levitation device, or the like is provided on the upstream side of the wastewater treatment device, and the oil / fat contained in the wastewater is removed before the treatment. If the wastewater containing fats and oils can be pretreated and the fats and oils can be sufficiently removed by a grease trap or pressure levitation, the concentration of fats and oils in the wastewater will also decrease, and the fats and oils that must be disposed of as industrial waste will inevitably be reduced. The amount of sludge can be reduced, and at the same time, the amount of sludge to be treated as industrial waste is reduced. This will reduce the amount of chemicals used, which will result in a significant reduction in industrial waste treatment costs. The oil and fat collected as industrial waste by the grease trap is usually called scum, and the oil and fat collected as industrial waste from the pressure flotation device is usually called floss.

The terms "fats and oils", "scum" and / or "floss" used in the present specification can be interpreted only when there is a particular limitation or from the description in the present specification. It should be noted that, unless clearly indicated, it is not used in any way intended to have any limited or specified meaning.

The oils and fats such as scum and floss recovered as described above also contain a large amount of water, and in order to incinerate them as they are, the incineration efficiency is low and a large amount of petroleum fuel is used. At the same time needed and extremely uneconomical,
A large amount of carbon dioxide is emitted, which is one of the causes of environmental pollution. Therefore, it is strongly demanded to establish a method for highly efficiently separating and recovering the oil and fat from the high-oil-and-fat-containing wastewater and efficiently incinerating the separated and recovered oil and fat.

[0006] As described above, oils and fats such as scum and floss recovered from wastewater are mixed with sludge generated from wastewater treatment and then dehydrated by a dehydrator to be incinerated as organic sludge (dehydrated cake). Often disposed of. However, if the organic sludge containing such fats and oils can be recycled and effectively used as a resource, the absolute amount of industrial waste to be incinerated can be significantly reduced. At the same time, the fuel and labor costs required for the incineration can be saved significantly. If the absolute amount of industrial waste to be incinerated can be significantly reduced, naturally, the emission of waste gas such as carbon dioxide can also be significantly reduced. If the absolute amount of industrial waste to be incinerated can be reduced in this way, it will be extremely useful as a treatment method for highly water-containing industrial waste that is extremely environmentally friendly.

[0007] Furthermore, as one of the effective utilization methods of such organic sludge as a resource, the organic sludge is also composted. However, such organic sludge is
Due to the high content of fats and oils, spoilage often occurs during composting. Therefore, in order to use the organic sludge for compost, the present situation is that an organic sludge which does not contain fats and oils and whose origin and properties are clear is required.

[0008] Furthermore, if the recovered oil and fat can be reused as fuel, it leads to a great reduction in the amount of waste and also a great reduction in the amount of petroleum fuel consumed for incineration, and it is contained in the wastewater. The oils and fats can be effectively used as a resource. Moreover, if the oil and fat recovered from the waste water is reused as boiler fuel or the like to generate steam or the like, it can be used as a heat source and also a generator or the like can be rotated. Therefore, it is possible to significantly reduce the amount of fuel used as a resource.

[0009]

In view of various problems of the above-mentioned prior art, the present inventor has diligently studied to solve such problems, and as a result, it has been confirmed that oils and fats such as scum and floss are removed from wastewater containing oils and fats. The present invention has been completed by discovering a method for effectively and efficiently separating and recovering and an oil and fat processing device, and finding that the separated oil and fat can be reused as fuel and the like.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for efficiently separating oil and fat such as scum and floss from waste oil containing oil and fat. In order to achieve the above object, the present invention, as one form thereof, comprises dissolving an oil / fat contained in wastewater in an organic solvent and separating / recovering the oil / fat contained in the organic solvent from the organic solvent. Also provided is a method for recovering fats and oils from wastewater, which comprises separating and recovering the oil. As a preferred embodiment of the above aspect, the present invention is to add an organic solvent to oil-fat-containing wastewater or oil-fat-containing wastewater reduced by concentration or the like, dissolve the oil-fat in the organic solvent, and separate and recover the oil-fat from the organic solvent. A method for recovering fats and oils is provided.

As another preferred embodiment of the above-mentioned mode, the present invention is to add an organic solvent to the oil / fat separated from the oil / fat-containing wastewater, dissolve the oil / fat in the organic solvent, and separate / recover the oil / fat from the organic solvent. A method for recovering fats and oils is provided. In a further preferred embodiment, the present invention further reduces the amount of oil / fat separated from the oil / fat-containing wastewater, adds an organic solvent to the reduced amount of oil / fat, dissolves the oil / fat in an organic solvent, and removes the oil / fat from the organic solvent. There is provided a method for recovering fats and oils, which comprises separating and recovering.

As a further preferred embodiment of the above-mentioned embodiment, the present invention provides a method for recovering oil and fat from wastewater, wherein the oil and fat is scum or floss.
In a more preferred embodiment, the present invention is, for example,
Provided is a method for recovering fats and oils from wastewater, which comprises using an organic solvent capable of dissolving fats and oils in wastewater such as hexane, chloroform, benzene, and toluene. Further, as a particularly preferred embodiment, a method for recovering fats and oils using n-hexane as an organic solvent is provided.

As a preferred embodiment, the present invention provides a method for recovering oil and fat from waste water, which comprises separating an organic solvent in which oil and fat content in the waste water is dissolved from the water content of the waste water. Furthermore, the present invention, as its preferred embodiment,
By treating an organic solvent containing such an oil / fat with a condition under which the organic solvent evaporates, the organic solvent is separated and recovered from the oil / fat, and the oil / fat from wastewater is obtained by separating and recovering the oil / fat. Provide a method of collecting minutes. Furthermore,
The present invention provides a method for recovering fats and oils, which comprises separating and removing solid matter (such as dust) contained in the organic solvent by filtering or the like.

As another aspect, the present invention provides a method for reusing oil / fat from wastewater, which comprises reusing the oil / fat recovered from the wastewater as described above as a fuel. Further, as a preferred embodiment thereof, the present invention is
Provided is a method for reusing oil / fat from wastewater, which comprises reusing such recovered oil / fat from wastewater for boiler fuel or the like.

According to another aspect of the present invention, an oil / fat treatment tank equipped to heat and cool the oil / fat from wastewater,
Heating / heating for heating / cooling the oil / fat contained in the tank
A medium supply port that supplies a cooling medium, a medium discharge port that discharges the heating / cooling medium, and an oil / fat component is heated by the heating medium to separate from other components, and the separated other components are discharged. An oil and fat treatment device comprising a discharge port for As a preferred mode of this aspect, the present invention is characterized in that the oil / fat treatment tank capable of heating / cooling has a double-wall structure or a piping structure, and a heating / cooling medium is passed through the structure inside the tank. Provided is an oil and fat treatment device configured to heat and cool the oil and fat content of the above.

In still another embodiment of the present invention, the oil and fat content of the waste water supplied to the waste water treatment layer is heated and dissolved by a heating medium to separate it from other components contained in the waste water, and the dissolved oil and fat content is then separated. A method for recovering fats and oils is provided, which comprises recovering fats and oils by solidifying the oil with a cooling medium and removing other separated components. Further, as a preferred form of this aspect, the present invention is to dissolve the oil and fat after separating other components by further heating with a heating medium, and filtering the dissolved oil and fat with a filter or the like. Provided is a method for treating fats and oils, which comprises recovering the fats and oils by removing impurities contained in the fats and oils.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Each mode of the present invention will be described in more detail. It should be understood that the present invention is not limited to the embodiments described below, and the embodiments described below are illustrative. A method of recovering fats and oils from wastewater as one embodiment of the present invention comprises dissolving the fats and oils contained in the wastewater in an organic solvent and separating and collecting the fats and oils from the organic solvent. Wastewater containing fats and oils that are the subject of this invention include, for example, wastewater from meat processing plants such as beef, pork, and chicken, wastewater from food processing plants, and wastewater containing fats and oils such as night soil from pig farms. However, the wastewater is not particularly limited as long as it contains fats and oils that are dissolved in an organic solvent to which the wastewater is added, and the wastewater that can be used may be of any origin and property. It should be noted that, due to the nature of the present invention, it is natural that a substance containing a high concentration of fats and oils is convenient and convenient for handling, but even if the concentration of fats and oils is low, it is not concentrated. The present invention can be applied without any problem as long as the amount can be reduced by recovery or the fat and oil can be recovered by any physical or mechanical means. In general, the amount of fats and oils contained in the wastewater is not particularly limited, and there is no problem as long as it is dissolved in the amount of the organic solvent to be added. However, about 0.5% may be included. Since wastewater generally contains a large amount of solid matter (such as dust), solid matter having a certain size is filtered by a solid matter removing device or means such as a filter. Therefore, it is preferable to remove the oil and fat before the recovery.

According to the method for recovering fats and oils according to the present invention, a predetermined amount of an organic solvent is added to the wastewater to be treated or the fats and oils such as scum and floss contained in the wastewater, and the oil is constantly stirred. The oil and fat is dissolved in the organic solvent by the stirring and mixing means according to the method. In the present invention, generally, adding an organic solvent to oil-and-fat-containing wastewater is not economical and extremely inefficient because a large amount of organic solvent is required. It is possible to add an organic solvent to the wastewater after concentrating the wastewater according to a conventional method to reduce its water content, but the water content of the wastewater thus concentrated is too high, and the oil and fat content in the wastewater is reduced. In order to dissolve it, a large amount of organic solvent is generally required, which is uneconomical. Of course, when the water content in the waste water is low, it is possible to add the organic solvent as it is to the oil and fat.

In the present invention, it is generally preferable to recover the fat and oil from the wastewater to be treated in advance. As a method of recovering oil and fat from wastewater, for example, a method of storing the wastewater in a water tank or the like and allowing it to naturally separate the oil and fat and water to recover the oil and fat, and the grease trap as a scum Examples thereof include a method of collecting and a method of collecting oil and fat as floss by a pressure floating device. It is preferable that the fats and oils such as scum and floss recovered from the wastewater are dissolved in the organic solvent by adding the organic solvent. Since oils and fats such as scum and floss recovered from wastewater still generally contain a large amount of water, it is not efficient to add an organic solvent to such high water-containing oils and fats. Not economical. If the organic solvent can be added after reducing the water content from such a high water content oil and fat, the oil and fat can be dissolved in the organic solvent more efficiently and economically.

As a means for reducing the water content of oils and fats such as scum and floss recovered from wastewater, any conventional method can be used. As a general method, for example, a method of naturally drying and concentrating the recovered fats and oils, a method of heating and drying the recovered fats and oils to concentrate it, a method of applying a load to the recovered fats and oils to concentrate it, a recovered fats and oils Examples include a method of re-collecting after heating and dissolving,
The method is not limited to these methods, and any method can be used as long as it can achieve the purpose of reducing the water content of the recovered fats and oils. Since the recovered fats and oils thus concentrated have a low water content, they can be more efficiently and quickly dissolved in the organic solvent by adding the organic solvent.

A method of heating and dissolving the recovered oil and fat, which is one of the means for reducing the water content of the recovered oil and fat from the waste water as described above, and then re-recovering it will be described in more detail. For example, this method is very effective in reducing the water content of floss recovered from wastewater. In this method, for example, the floss is heated to dissolve the fats and oils in the floss and floated on the surface of the floss, and then the floss is cooled to solidify the melted fats and oils and at the same time contained in the floss. It consists of separating water from fats and oils. The water layer separated from the oil and fat can be removed by draining from a drain or the like on the bottom surface, for example. Further, solid matters such as dust are separated from the oil and fat and settle at the bottom of the water layer, so that they can be removed together with the wastewater of the water layer. The drained water layer can be returned to the adjusting tank. Dust and the like removed together with the drained water layer can be removed by, for example, a filter and treated by incineration. The oil and fat recovered as described above has a very low water content, but for example, by putting it in a storage tank and placing a punching metal such as stainless steel on it and leaving it under a load, the water content is further reduced. The content can be reduced. The fats and oils thus recovered can be incinerated as they are, or if the recovered fats and oils contain few contaminants such as dust, they can be reused as fuel and the like.

As described above, in order to concentrate the recovered fats and oils such as floss from the wastewater, the recovered fats and oils are heated to dissolve the fats and oils, and then the dissolved fats and oils are cooled and solidified. You can Therefore, in principle, this method can be carried out by using an oil and fat processing apparatus which has heating and cooling equipment and which can be heated and cooled and whose structure is extremely simple.

An example of such an oil and fat processing device will be described with reference to FIG. As shown in the figure, the oil and fat processing apparatus generally includes a fat and oil processing tank 1 that can be heated and cooled, an oil and fat supply port (not shown) for supplying oil and fat to be processed therein, and a bottom side surface thereof. A medium supply port 2 for supplying a medium for heating and cooling the oil and fat provided, a medium discharge port 3 for discharging the medium provided on the upper side surface of the wall, and a discharge port 4 provided at the bottom thereof. ,,. In the fat and oil processing apparatus having the configuration as shown in FIG. 1, the fat and oil such as floss supplied to the fat and oil processing tank 1 from the fat and oil supply port (not shown) is fed from the medium supply port 2 provided on the bottom side surface thereof. The heating medium is supplied into the wall of the oil / fat treatment tank 1 to dissolve the oil / fat contained in the floss or the like. The dissolved fats and oils float on the surface and separate from the water layer. Next, a cooling medium is supplied to the fat and oil treatment tank 1 from the medium supply port 2 or a separately provided medium supply port to cool it,
Solidify the dissolved fat and oil. By solidifying the dissolved fat and oil in this manner, it can be easily separated from the aqueous layer. The solidified fats and oils can be easily recovered by draining the water layer from the drain port (drain) 4 provided at the bottom of the tank.

The structure of the oil / fat treatment tank 1 is to heat and melt the oil / fat component such as floss in the tank, and then to cool and solidify the dissolved oil / fat component, so that the tank can be heated and then cooled. It may have any configuration, and is not limited to a specific configuration. The oil and fat processing tank 1 is generally
It is preferable that the whole tank can be heated and cooled, for example,
To make the entire tank wall a double wall structure, and to supply the heating medium such as warm water and the cooling medium such as cold water to the inside to heat and cool the entire tank wall and bottom tank. It is recommended that the configuration be such that In the case of this configuration, for example, it is preferable that the medium is supplied from the bottom side surface on the one end side of the tank and is discharged from the tank wall upper side surface on the opposite side. As another configuration, piping may be attached to the tank wall and the bottom of the tank, and heating and cooling media may be supplied into the piping to heat and cool the treated oil and fat. it can.

The fats and oils thus collected are preferably left in the storage tank until the next treatment. Even during the standing period, the recovered oils and fats continue to be dried to release water, and the water content becomes very small. If a stainless steel punching metal or the like is placed on top of this oil and fat and a load is applied, the release of water is further promoted.
In this case, if an outlet is provided at the bottom of the storage tank, the released water will naturally flow out from the outlet, and the remaining oil and fat will have an extremely low water content. In this way, the oil and fat having an extremely low water content has a very high incineration efficiency during incineration and can greatly reduce the petroleum fuel required for incineration, and at the time of reuse,
It can be said to be an extremely environmentally friendly recycling technology that can be reused with high thermal efficiency.

A method of operating the illustrated fat and oil processing apparatus will be briefly described with reference to FIG. The recovered fats and oils such as floss collected from the wastewater are supplied to the fat and oil treatment tank 1 from a fat and oil supply port (not shown), and the medium supply port 2 is heated to about 60 to 90 ° C. while being stirred by a stirrer installed in the tank. A warming medium such as hot water is supplied to the inside of the tank wall or piping installed inside the tank to heat and dissolve the oil and fat, and separates from the water contained in the floss to form a water layer. It emerges on the surface. Then, 5 ° C to 10 ° C inside the tank wall or in the pipe
By supplying a cooling medium such as cold water at about ℃ to solidify the dissolved fat and oil, the solidified fat and oil layer and the water layer are clearly separated. The water layer can be easily drained from the drain. At the bottom of the water layer, the collected oils and fats often contain contaminants such as dust, or such contaminants can be removed together with the discharge of the water layer. The discharged water layer can be disposed of after being stored in the adjustment layer. Contaminants such as dust in the discharge water tank can be removed by a filter or the like and disposed of by incineration.

On the other hand, the recovered fats and oils can be processed after being temporarily stored in the storage tank as described above. By further heating the recovered fats and oils to form a solution, they can be easily recovered from the processing tank. In addition, since the oil and fat in the solution state also contains light contaminants such as dust, the recovered oil and fat is collected with a filter etc. according to the purpose of reuse to recover a higher purity oil and fat. It is also possible to do so.

Next, the organic solvent that can be used in the present invention will be described. As such an organic solvent, any organic solvent that can dissolve such fats and oils can be used. Further, the organic solvent to be used, depending on the type and properties of the fats and oils to be separated and recovered, it is preferable to appropriately select the type and properties,
Generally, it is preferable to appropriately select from chlorinated hydrocarbons such as hexane, chloroform, benzene, and toluene, aromatic hydrocarbons, and the like. Of these organic solvents, n-hexane is generally more preferable. The amount of the organic solvent used is also not particularly limited, and it may be appropriately selected and used depending on the concentration and properties of the oil and fat content in the waste water to be treated. As an example, the amount of an organic solvent such as hexane or chloroform is, for example, generally about 10% by weight to 150% by weight, preferably about 30% by weight to 120% by weight, based on the fat or oil to be treated. Is good. As a matter of course, the amount of the organic solvent to be added can be appropriately adjusted depending on the concentration of oil and fat in the waste water to be treated.

Next, the method of adding an organic solvent to waste water or fats and oils to dissolve the fats and oils is not particularly limited, and any method can be used as long as it can dissolve the fats and oils in the organic solvent. be able to. For example, by mechanically stirring and mixing a mixed solution of an organic solvent and waste water or fats and oils with a stirrer or the like, generally, an organic solvent layer, a water layer, and a sludge layer are separated, and fats and oils are separated. The fraction is dissolved in the organic solvent layer in a solution state or an emulsified state.

In the above case, the waste water or fats and oils are generally separated in the order of the organic solvent layer as the upper layer, the water layer as the intermediate layer, and the sludge layer as the lower layer. Then, the organic solvent layer can be recovered by draining the aqueous layer to the intermediate layer or the upper organic solvent layer by overflow or the like. Even if the method of separating and collecting the organic solvent layer from the water layer and the sludge layer is not limited to these methods, any method can be used as long as it can effectively separate and collect the organic solvent layer. can do.

As a method for recovering the oil / fat from the organic solvent layer recovered as described above, any method can be used as long as it can recover the oil / fat dissolved or suspended in the organic solvent. The method is not particularly limited, and any method can be used. As such a method, for example, a method of heating the organic solvent layer to evaporate the organic solvent in an oil bath, a hot water bath or the like to separate and recover the organic solvent and the fat and oil can be used. If necessary, an evaporator, an aspirator or the like can be used. The method for separating and collecting the oil and fat from the organic solvent layer is not limited to this method at all, and any method can be used as long as it can effectively separate and collect the oil and fat from the organic solvent layer. When the organic solvent layer is evaporated to separate and collect the organic solvent and the fat and oil, the organic solvent and the fat and oil vaporized by evaporation or the like can be easily collected by cooling. The organic solvent thus recovered is
It can be effectively reused for recovery of fats and oils from wastewater. The temperature for heating the organic solvent layer may be appropriately selected and determined based on the types and properties of the organic solvent and oil and fat to be separated and recovered, but the heating temperature is generally
Since it depends on the boiling point temperature of the components of the organic solvent layer, the organic solvent and the oil and fat can be separated by heating the organic solvent layer at the boiling point temperature of the organic solvent used. The organic solvent thus separated from the organic solvent layer by evaporation or the like is preferably returned to a liquid by cooling or the like and recovered. The organic solvent thus recovered can be recycled and reused. By reusing the separated and recovered organic solvent, the total amount of the organic solvent used can be saved, and as a result, the cost required for the treatment can be significantly reduced.

On the other hand, the fats and oils contained in the organic solvent can be recovered as a residue after the organic solvent is removed by evaporation or the like. The fats and oils thus recovered are extremely advantageous when they are reused, because they have a very low water content and impurities and are composed of a high concentration.

The organic solvent layer recovered as described above may contain foreign matters such as dust. In the case where such contaminants may have an adverse effect on the separation and recovery of the oil and fat from the organic solvent layer, or may have an adverse effect on the reuse of the separated and recovered organic solvent and / or the oil and fat, use a filter or the like. It is preferable to separate them by conventional means such as filtration.

The sludge layer separated and recovered from the organic solvent layer and the water layer by adding the organic solvent to the oil and fat from the waste water as described above is used for incineration or used as a material for compost. You can also Since the sludge layer that has been separated and collected still contains a large amount of water, it is recommended to dry it by a conventional method to reduce its water content before incinerating it or using it as compost. Good. The sludge thus recovered can be mixed with the oil and fat separated and recovered from the organic solvent layer and used as an organic sludge (dehydrated cake) as a material for compost. However,
When sludge is used as a compost material, it is often selected according to the origin and properties of the sludge, and when such organic sludge is used as a material for compost, the oil and fat content in the organic sludge is Care should be taken not to rot the compost.

On the other hand, the water layer separated and recovered from the organic solvent layer and the sludge layer by adding the organic solvent to the fats and oils from the waste water as described above can be removed by, for example, a drain. The removed water layer can be treated, for example, by discharging the water after temporarily storing the water in a conditioning layer or the like. For example, when the BOD value of the water layer is high, it may be better to carry out discharge disposal after transferring to an aeration tank for aeration treatment. In other words, it is better to perform discharge treatment after performing necessary treatment according to the properties of the water layer. If light contaminants such as dust are mixed in this water layer, it can be removed by a filter or the like, if necessary.

The fats and oils separated and recovered from the organic solvent as described above can be reused, for example, as fuel or fertilizer. Of these, the recovered fats and oils are fuel,
For example, it is preferable to reuse it as boiler fuel. The steam generated by using such oils and fats as a boiler fuel can also be used in a wide range of fields as an economical heat source. Since the recovered oil and fat retains a liquid state as long as it is heated, it is preferable to heat and store the oil and fat for use as fuel or the like. For that purpose, a heater can be installed in a container such as a tank for storing the recovered oil and fat, and the oil and fat can be heated and held in a liquid state.

[0037]

EXAMPLES The present invention will be described in more detail by way of examples. Example 1: Experiments were carried out using wastewater containing froth (3% fat) from a broiler plant. Waste water 500
200 ml of n-hexane was added to 30 ml,
The waste water and hexane were thoroughly mixed by stirring for 1 minute, and the oil and fat content in the waste water was dissolved in hexane. The obtained mixed liquid was allowed to stand for a while and then filtered through a filter paper to remove dust in the waste water.
The obtained filtrate was separated into n-hexane and fats and oils with a 35 ° C water bath (with a rotary evaporator). The separated n-hexane was cooled with 5 ° C. cooling water and recovered. As a result, the recovery of n-hexane was about 55% and the recovery of oil and fat was about 1.5% (vs waste water).

Example 2: When the boiler was operated using the oil and fat collected in Example 1 placed in a container (heated at around 50 ° C.) with a heater as a fuel, a sufficient amount of steam could be generated. Further, they have found that even if such oils and fats are used, they can be economically used as a boiler fuel.
Furthermore, it goes without saying that the steam obtained can be used in all possible applications.

Example 3: 500 ml of floss obtained from wastewater from a broiler factory was placed in a beaker, stirred thoroughly, and 200 ml of n-hexane was added and mixed well to dissolve fats and oils. This mixture is 3,000 rpm
After centrifugation for 5 minutes, the mixture was separated into an organic layer, an aqueous layer and a precipitation layer. A floating material layer was obtained between the organic layer and the aqueous layer. The organic layer was pipetted, transferred to a round-bottomed flask, the flask was attached to a rotary evaporator and the hexane was evaporated on a 35 ° C. water bath to separate. The separated n-hexane was cooled with 5 ° C. cooling water and recovered. As a result, the recovery rate of hexane was about 55%.
In addition, the oil and fat remaining as a residue in the flask was collected and weighed, and it was 8.9 g (extraction rate 1.8%).

Example 4: The oil and fat recovered in Example 3 was put into a container (heated at around 50 ° C.) equipped with a heater, and the boiler was operated as a boiler fuel. As a result, a sufficient amount of steam could be generated. Therefore, it has been found that such fats and oils can be economically used as a boiler fuel. Furthermore, it goes without saying that the steam obtained can be used in all possible applications.

Example 5: 1,000 ml of floss collected from wastewater of a broiler plant was placed in a beaker at 60 ° C-
The mixture was heated in a warm bath at 65 ° C. for 1 hour with occasional stirring. When it was left to cool and then left to stand overnight, the floss was separated into two upper and lower layers. The upper layer consisted of a lot of air bubbles and a soft mud-like solid matter, the lower layer consisted of a cloudy water layer, and dust-like precipitates were accumulated at the bottom. This aqueous layer (570 ml) was removed. The water analysis was performed as follows. To 200 ml of the separated aqueous layer, 120 ml of n-hexane was added, and the mixed solution was transferred to a separating funnel, shaken for 5 minutes, and allowed to stand for 1 hour. Separated into a cloudy aqueous layer. From this appearance observation, it was judged that the upper hexane layer contained almost no fat and oil. The analysis results of this water tank are shown in Table 1 below.

[0042]

[Table 1]

Layer 4 containing solid matter after removal of the aqueous layer
400-500 ml of n-hexane was added to 30 ml,
After stirring for 10 minutes and standing still, the mixed solution was composed of a hexane layer as an upper layer, an insoluble matter layer as an intermediate layer and an aqueous layer as a lower layer.
The layers were separated. As a result of this example, the volume of the froth solid content after solid-liquid separation was reduced by 57% of the untreated froth amount.

[0044]

As described above, according to the method for recovering oil and fat from wastewater according to the present invention, an organic solvent is added to wastewater containing oil and fat to dissolve the oil and fat in the organic solvent, It consists of separating and recovering from the solvent. Therefore, it is possible to easily and efficiently and economically separate and recover the oil and fat contained in the wastewater from the wastewater. In addition, oils and fats such as scum and floss, which were conventionally incinerated as they are with petroleum fuel (heavy oil) (mostly waste water as is)
However, according to the present invention, there is an extremely great advantage that the recovered oil and fat can be reused as fertilizer or fuel, in addition to being easily recovered in a state containing almost no water. Furthermore, if the recovered fats and oils are used as boiler fuel, there is an extremely great advantage that steam generated in the boiler can also be used as an extremely inexpensive and economical heat source. Even in the organic solvent used in this invention,
Since it is not a special one and one that can be easily and inexpensively obtained can be used, the wastewater treatment cost can be significantly reduced as compared with the cost required for the incineration disposal up to now. This invention, since the solid matter as miscellaneous waste contained in wastewater can be easily removed by a physical means such as filtration in a state where the oil and fat content to be recovered is dissolved, the oil and fat recovery efficiency can be improved. Can be kept high.

Further, according to the present invention, by heating the oil and fat recovered from the wastewater to separate it from the water contained therein, the water content can be further reduced, and industrial waste such as incineration can be disposed of. This has the great advantage that the recovered oil and fat can be reused as a resource with higher added value. Further, the oil / fat component having a low water content thus recovered can be efficiently and easily recovered by applying a load or leaving it to stand without applying a load. It also provides the big advantage.

The sludge layer obtained by separating oils and fats according to the present invention contains little or no oils and fats that may cause rotting when used as compost, and therefore can be effectively used as compost. There are great advantages from the viewpoints of resource reuse and reduction of industrial waste treatment. Further, according to the present invention, it is possible to further recover the oil / fat having a low water content or almost no water by concentrating the recovered oil / fat from the wastewater, and thus the oil / fat is mixed with the sludge to be composted. It is also possible to do so.

In addition, since the present invention can reuse the fats and oils separated and recovered from the wastewater as fertilizers and fuels, it is extremely economical as compared with the conventional incineration. It's obvious. Wastewater treatment costs can be significantly reduced by this reuse. Further, if the oil and fat separated and recovered according to the present invention is reused as a boiler fuel, steam generated from the boiler can also be used for various purposes as an inexpensive and extremely economical heat source. Further, according to the present invention, since the organic solvent separated from the oil and fat can also be recycled and reused, the amount of the organic solvent used can be significantly reduced, and the treatment cost of the entire wastewater treatment can be significantly reduced. can do.

[Brief description of drawings]

FIG. 1 is a sectional side view showing one embodiment of an oil and fat processing device according to the present invention.

[Explanation of symbols]

1 oil and fat processing tank 2 Medium supply port 3 Medium outlet 4 drain (drain)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C11B 13/00 C11B 13/00 F term (reference) 4D051 AA01 AA04 AB02 BA02 4D056 AB14 AC02 AC03 AC04 CA14 CA20 CA22 CA31 4D076 AA12 AA13 BA01 DA02 DA21 FA02 FA04 FA16 FA25 HA03 HA06 4H013 BA00 4H059 BA01 BA02 BA04 BC03 BC13 CA02 CA12 CA94 CA96

Claims (18)

[Claims] 1. An oil and fat component from waste water, characterized in that the oil and fat contained in the waste water is dissolved in an organic solvent to separate and recover the oil and fat component from the organic solvent, and the organic solvent is separated and recovered. Recovery method. 2. The method for recovering oil and fat from wastewater according to claim 1, wherein the organic solvent is added to the wastewater containing the oil and fat to dissolve the oil and fat in the organic solvent. A method for recovering fats and oils from wastewater, characterized in that the oil is separated and recovered from the organic solvent. 3. The method for recovering fats and oils from wastewater according to claim 1 or 2, wherein the amount of the wastewater containing the fats and oils is reduced to add the organic solvent. Recovery method. 4. The method for recovering fats and oils from wastewater according to claim 1, wherein the organic solvent is added to the fats and oils separated from the wastewater to dissolve the fats and oils in the organic solvent. A method for recovering fats and oils from wastewater, which comprises separating and recovering the components from the organic solvent. 5. The method for recovering fats and oils from wastewater according to claim 1 or 4, wherein the fats and oils are physically or mechanically separated and recovered from the wastewater. Recovery method. 6. The method of recovering oil and fat from wastewater according to claim 4 or 5, wherein the oil and fat separated from the wastewater is further reduced, and the organic solvent is added to the reduced oil and fat. Characteristic method for recovering fats and oils from wastewater. 7. A method of recovering oil and fat from wastewater according to claim 1, wherein the oil and fat is scum or floss. . 8. A method for recovering oil and fat from wastewater according to any one of claims 1 to 7, wherein the organic solvent is hexane, chloroform, benzene or toluene. How to recover the minutes. 9. A method of recovering oil and fat from wastewater according to claim 1, wherein the organic solvent is n-hexane. . 10. A method for recovering oil and fat from wastewater according to claim 1, wherein the organic solvent in which the oil and fat is dissolved is separated and recovered from the wastewater. A method of recovering fats and oils from wastewater. 11. The method for recovering oil and fat from wastewater according to claim 1, wherein the organic solvent in which the oil and fat is dissolved is treated under the condition that the organic solvent evaporates. A method for recovering oil and fat from wastewater, characterized in that the organic solvent is separated and recovered from the oil and fat. 12. The method for recovering oil and fat from wastewater according to claim 1, wherein the solid matter contained in the wastewater is separated and removed by filtration or the like. Of collecting fats and oils from oil. 13. A method for reusing oil / fat from wastewater, characterized in that the oil / fat recovered from the wastewater according to any one of claims 1 to 12 is reused as a fuel. 14. The method for reusing oil and fat from wastewater according to claim 13, wherein the fuel is boiler fuel. 15. A heating / cooling oil / fat processing tank, an oil / fat supply port for supplying an oil / fat to be processed into the oil / fat processing tank, a medium supply port provided on a bottom side surface of the oil / fat processing tank, and the oil / fat. It comprises a medium outlet provided on the upper side surface of the wall of the treatment tank and an outlet provided at the bottom of the oil and fat treatment tank. The oil and fat recovered from waste water is supplied to the inside of the oil and fat treatment tank, A warm medium is supplied from the medium supply port to heat the oil and fat to separate the oil and fat from other components, and a refrigerant body is supplied from the medium supply port to solidify the oil and fat to separate the other components from the medium. An oil and fat processing device characterized in that the oil and fat is discharged from the discharge port. 16. The oil-and-fat processing apparatus according to claim 15, wherein the oil-and-fat processing tank capable of heating and cooling has a double wall structure or a piping structure so that a medium can pass through the inside of the oil-and-fat processing tank. An oil and fat processing device characterized in that the inside can be heated and cooled. 17. An oil / fat separation step of dissolving waste oil / fat recovered from wastewater in a warm medium to separate it from other components contained in the oil / fat, and the dissolved oil / fat separated by the oil / fat separation step is solidified by a refrigerant body. A waste oil and fat treatment method comprising a fat and oil solidifying step and a discharging step of discharging the other component separated in the oil and fat separating step. 18. The waste oil and fat treatment method according to claim 17, wherein the oil and fat obtained in the discharging step is heated and dissolved,
A method for treating waste fats and oils, which comprises removing impurities contained in the fats and oils to recover the fats and oils.