JP2008013638A - Method of treating oils and fats-containing waste water and its treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of treating oils and fats-containing waste water which can separate waste oils and fats from oils and fats-containing waste water collected in a grease trap to obtain a waste oils and fats solidified substance with good handling properties by an easy recovery operation. <P>SOLUTION: The method of treating oils and fats-containing waste water comprises adding at least one oils and fats solidifying agent selected from the group consisting of stearic acid, 12-hydroxystearic acid, and paraffin to the waste oils and fats separated from the oils and fats-containing waste water collected in the grease trap 5, heating the resulting mixture at a temperature of not lower than the melting point of the oils and fats solidifying agent, then introducing the heated mixture into cooling water, and cooling and solidifying the above waste oils and fats to obtain the waste oils and fats solidified substance 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for treating oil-containing fat wastewater that separates and collects waste oil-and-fat from oil-containing fat and wastewater discharged from kitchens, food factories, and the like, and a treatment apparatus used therefor.

  Wastewater from kitchens for commercial purposes such as lunch centers, hotels, inns, restaurants, or general restaurants, meat centers, food / fishery processing plants, and the like contains a large amount of raw garbage, animal and vegetable oils and fats, and the like. It is obliged to install a grease trap for the purpose of preventing such raw garbage, animal and vegetable oils and fats from flowing into sewage as they are.

  In general, in the grease trap, garbage etc. contained in the wastewater is collected by a strainer, and the wastewater is further separated into waste oil and water by the difference in specific gravity in the grease trap. In addition, by providing a slide plate / partition plate, the speed of waste water flowing into the grease trap is reduced to keep the separated state of waste oil and water.

  As a method for collecting the oil-containing fat wastewater collected in the grease trap, for example, there is a method of periodically requesting a cleaning company and manually collecting it, but there is a problem because the working environment is poor due to bad odors and the like.

  Japanese Patent Laid-Open No. 2001-162274 (Patent Document 1) describes a floating oil automatic recovery device that can recover turbid water containing waste oil floating above the recovery tank using a pump. . By using this floating oil automatic recovery device, there is no need for manual recovery of the floating waste oil in the grease trap, so there is no need for trouble, and it is said that the bad odor and clogging of the pipes can be greatly reduced. However, the recovered waste oil and fat is difficult to handle when transported due to its shape, and there is a problem in that it takes effort when disposing it as waste.

  JP-A-55-106298 (Patent Document 2) adds a suitable amount of 12-hydroxystearic acid to waste edible oil, heat-dissolves, and then cools the solidified treatment of waste edible oil. The method is described. However, such a solidification method is a method in which 12-hydroxystearic acid is directly added to waste edible oil, and an example of application when there is a lot of water such as oil-containing fat wastewater collected in a grease trap is There wasn't.

JP 2001-162274 A JP 55-106298 A

  The present invention has been made in order to solve the above-mentioned problems, and can separate waste oil from the oil-containing fat waste water collected in the grease trap, thereby obtaining a solidified waste oil that is easy to handle and easy to collect. It aims at providing the processing method of oil-containing fat wastewater. It is another object of the present invention to provide such a processing apparatus.

  The above-mentioned problem is a method for treating oil-containing fat wastewater, wherein the oil-and-fat solidified product is obtained by solidifying the waste oil-and-fat by adding an oil-and-fat solidifying agent to waste oil and fat separated from the oil-and-fat wastewater collected in the grease trap. Solved by providing.

  At this time, it is preferable to add an oil and fat solidifying agent and heat and then cool, and it is preferable to cool waste water and fat heated to the melting point or higher of the oil and fat solidifying agent in cooling water. It is preferable that the difference between the temperature of the heated waste oil and the temperature of the cooling water is in the range of 20 to 100 ° C, and the oil solidifying agent is an aliphatic compound having a melting point in the range of 40 to 100 ° C. Is preferred. In addition, it is preferable that the oil / fat solidifying agent is selected from the group consisting of stearic acid, 12-hydroxystearic acid and paraffin, and that the hexane extract of the waste oil / fat solidified product is in the range of 60 to 100% by weight. It is.

  Further, the above-mentioned problems include separation means for separating waste oil and fat from oil-containing fat and wastewater collected in a grease trap, heating means for heating the waste oil and fat to the melting point of the oil and fat solidifying agent in the presence of the oil and fat solidifying agent, and heating. The problem can also be solved by providing an oil-containing fat wastewater treatment apparatus comprising cooling means for cooling and solidifying the waste oil and fat.

  In the oil-containing fat wastewater treatment apparatus, the heating means is preferably a heating tank provided with a heater and a stirring device, and the cooling means is preferably a cooling water tank provided with a stirring device, and the cooling water tank with respect to the capacity of the heating tank It is also preferable that the capacity is twice or more.

  According to the method for treating oil-containing fat wastewater of the present invention, waste oil and fat can be separated from the oil-containing fat wastewater collected in the grease trap, and a solidified product of waste oil and fat that is easy to handle and easy to collect can be obtained. Moreover, since the water content of the obtained waste fat-solidified product is low, it can be suitably used as a fuel.

  Hereinafter, the present invention will be described more specifically with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a processing apparatus for oil-containing fat wastewater used in the present invention. Separation means for separating waste oil and fat from oil-containing fat wastewater accumulated in a grease trap, and the waste oil and fat are converted into aliphatic oil and fat. It comprises a heating means for heating to the melting point or higher of the oil / fat solidifying agent in the presence of the solidifying agent, and a cooling means for cooling and solidifying the heated waste oil / fat.

  As shown in FIG. 1, the wastewater containing waste oil and fat flowing out from the sink 2 such as a kitchen passes through the wastewater introduction pipe 3, and solids such as garbage are collected by the strainer 4, and then the grease trap 5 Can be stored. In the grease trap 5, the oil and fat components float to the upper layer due to the difference in specific gravity, and only the lower layer moisture is discharged through the discharge pipe 24.

  In the separation means in the processing apparatus 1 of the present invention, the waste oil and fat is separated from the oil-containing fat and wastewater. In the example of FIG. 1, of the oil-containing fat waste water collected in the grease trap 5, the upper oil-rich portion is sucked up using a pump or the like (not shown) and passed through the oil-containing fat waste water suction pipe 6. It is sent to the separation tank 7, and the waste oil and fat are separated from each other by the specific gravity difference in the waste oil and fat separation tank 7. The water separated in the waste oil separation tank 7 is led out from the waste oil separation tank 7. The derived waste water may be sent to the grease trap 5 through the waste water return pipe 19, or may be sent to the cooling water tank 13 through the waste water supply pipe 17 and used as cooling water. The waste oil and fat separated and accumulated in the waste oil and fat separation tank 7 by repeating the derivation of the waste water is sent to the heating tank 9. In the treatment method of the present invention, the operation of further separating waste oil and water from the oil-containing fat waste water separated by specific gravity in the grease trap 5 using such a separation means is performed. By performing this operation, it is possible to reduce the water content of the waste oil obtained. Some animal fats and oils are solid at room temperature, so a heater may be provided in the waste oil separation tank 7 to facilitate separation.

  In the treatment method of the present invention, an operation of adding an oil solidifying agent to waste oil separated from oil-containing fat wastewater is performed. By mixing the fat and oil solidifying agent with the waste fat and oil, the waste fat and oil is solidified together with the fat and oil solidifying agent. The timing for adding the oil solidifying agent is not particularly limited, and the added fat or oil may be added while stirring the waste oil or fat. It is preferable. The operation of adding the oil solidifying agent may be performed manually, or a means capable of automatically adding a certain amount of oil solidifying agent may be provided. It is preferable to provide a means for adding an oil solidifying agent because it can be easily operated.

  The oil solidifying agent used in the present invention is preferably an aliphatic compound having a melting point in the range of 40 to 100 ° C. When the melting point of the fat solidifying agent is less than 40 ° C, the shape stability of the obtained waste fat solidified product 15 may not be good, and more preferably 60 ° C or higher. On the other hand, when the melting point of the fat / oil solidifying agent exceeds 100 ° C., the fat / oil solidifying agent may not be melted during heating / stirring and mixing with the waste oil / fat may not be successful, and is preferably 90 ° C. or lower. Examples of suitable oil and fat solidifying agents include stearic acid, 12-hydroxystearic acid, paraffin and the like. Among these, the cost is low, the separability between the obtained waste oil solidified product 15 and water is good, and the particle size of the obtained waste fat solidified product 15 is large, and paraffin is more preferable.

  Although it varies depending on the moisture content of the waste oil and fat and the kind of the fat and oil solidifying agent, the addition amount of the fat and oil solidifying agent in the present invention is preferably 1 to 30 parts by weight per 100 parts by weight of the waste oil and fat. When the addition amount of the fat / oil solidifying agent is less than 1 part by weight, the shape stability of the obtained waste oil / fat solidified product 15 may be impaired, and more preferably 3 parts by weight or more. On the other hand, when the addition amount of the fat and oil solidifying agent exceeds 30 parts by weight, the processing cost increases, and it is more preferably 20 parts by weight or less.

  In the heating means in the processing apparatus 1 of the present invention, the waste oil and fat is heated to the melting point or higher of the oil and fat solidifying agent in the presence of the oil and fat solidifying agent. Waste oil and fat separated in the waste oil and fat separation tank 7 is introduced into a heating tank 9 and heated to the melting point or higher of the fat and oil solidifying agent in the presence of the oil and fat solidifying agent. It is preferable that the heating tank 9 includes a heater 11 and a stirring device 10, whereby waste oil and fat can be heated and stirred so that the oil and fat solidifying agent is not biased in the heating tank 9. In addition, by heating and stirring the waste oil and fat, the oil and fat content and moisture can be sufficiently separated, so that a waste oil and fat solidified product having a high hexane extract can be obtained.

  In the treatment method of the present invention, it is preferable to cool after heating after adding an oil solidifying agent to waste oil. By being cooled, the waste oil / fat is solidified to obtain a solidified product 15 of the waste oil / fat. The cooling means in the treatment apparatus 1 of the present invention cools and solidifies the heated waste oil and fat, and in the example of FIG. 1, a cooling water tank 13 filled with cooling water is used. It is preferable to cool waste oil and fat heated to the melting point or higher of the oil and fat solidifying agent into the cooling water in the cooling water tank 13 for cooling. The cooling means is preferably provided with a stirring device 14, which can cool uniformly and reduce variations in the shape of the waste oil solidified product 15.

  Although the temperature of the cooling water used when cooling is not particularly limited, the difference between the temperature of the waste oil heated by the heating tank 9 and the temperature of the cooling water in the cooling water tank 13 may be in the range of 20 to 100 ° C. preferable. When the temperature difference is less than 20 ° C., the waste oil / fat may not be rapidly solidified, and the variation of the shape of the obtained waste oil / fat solidified product 15 may increase, and is more preferably 30 ° C. or more. On the other hand, the temperature difference is usually 100 ° C. or less, but more preferably 90 ° C. or less from the viewpoint of cost and safety.

  In order to make the difference between the temperature of the waste oil and the temperature of the cooling water within the above-described temperature range, the capacity of the cooling water tank 13 with respect to the capacity of the heating tank 9 is preferably twice or more. When the capacity of the cooling water tank 13 is less than twice, the temperature of the cooling water rises, and there is a possibility that the waste oil / fat cannot be quickly solidified, and the variation in the shape of the obtained waste oil / fat solidified product 15 may be increased. More preferably, it is 5 times or more. Moreover, the capacity | capacitance of a cooling tank is 100 times or less normally.

  The method of supplying the cooling water to the cooling water tank 13 is not particularly limited, and may be supplied continuously or whenever the temperature of the cooling water in the cooling water tank 13 rises or the pollution load increases. May be. As the cooling water, the cooling water 20 may be supplied from the cooling water storage tank 21 through the cooling water supply pipe 23, or tap water may be directly supplied. The water separated in the waste oil separation tank 7 may be supplied from the waste water supply pipe 17. Further, the water in the lower layer in the grease trap 5 may be pumped and supplied.

  The method for recovering the waste oil solidified product 15 obtained by the above-described method is not particularly limited, and may be recovered manually using a net or may be recovered by coarse filtration. Moreover, you may collect | recover the waste oil-fat solidified material 15 using the automatic collection | recovery apparatus provided with the belt conveyor. The cooling water in the cooling water tank 13 remaining after the recovery of the waste oil solidified material 15 may be reused as it is or may be discharged to the grease trap 5.

  Moreover, it is preferable that the processing apparatus 1 of this invention is equipped with the spin-drying | dehydration means which spin-dry | dehydrates the collect | recovered waste fat and oil solids 15. By dehydrating and reducing the water content of the waste oil solidified product 15, it can be suitably used as a fuel. The water generated by the dehydration may be discharged as it is or may be sent to the grease trap 5. The method of dehydrating is not particularly limited, and may be drained using a net or the like, or may be dried with a dryer or the like.

  The waste water in the lower layer in the grease trap 5 is discharged from the discharge pipe 24. Since the oil-containing fat wastewater is recovered as the waste oil solidified product 15 by the treatment method of the present invention, the environmental burden can be reduced without the waste oil or fat flowing out from the discharge pipe 24.

  It is preferable that the hexane extraction part of the waste oil solidified material 15 obtained by the processing method of this invention exists in the range of 60 to 100 weight%. Here, the hexane extract of the waste oil solidified product 15 indicates a ratio of what is extracted using hexane, and roughly corresponds to the ratio of the fat contained in the waste fat solidified product 15. When this hexane extract is high, the water content of the waste oil solidified product 15 is usually low. When the hexane extract of the waste oil solidified product 15 is less than 60% by weight, the water content of the obtained waste fat solidified material 15 is increased and the total calorific value is often lowered, and the performance as a fuel may be lowered. More preferably, it is 70% by weight or more.

  In the treatment method of the present invention, it is preferable that the hexane extract from the waste oil solidified product 15 is larger by 10% by weight or more than the waste oil immediately after being separated from the oil-containing fat wastewater. Thereby, the waste oil-fat solidified product 15 having a low water content can be obtained. The increase in hexane extract is more preferably 20% by weight or more, and further preferably 30% by weight or more.

  The waste oil solidified product 15 obtained by the treatment method of the present invention has a low water content and uses an oil solidifying agent that does not contain nitrogen, phosphorus, sulfur, metal elements, and the like. It can be suitably used as a solid fuel with less generation of substances and the like.

  Hereinafter, the present invention will be further described using test examples. In this test example, a model test for the processing method of the present invention was performed.

Test example 1
20 g of simulated waste oil (vegetable oil: lard: water = 1: 1: 2) is heated to 80 ° C. while stirring, and 0.2 g, 0.4 g, 1 g and 2 g of paraffin (melting point: 68-70 ° C.) are used as an oil solidifying agent. Each was added. These simulated waste oils mixed with paraffin were put into 200 g of cooling water at 25 ° C., and the shape of the obtained solidified product and the seepage of the filter paper were observed. The obtained results are summarized in Table 1.

Test example 2
The upper layer of the oil-impregnated waste water collected in the grease trap installed at the pork bone ramen dealer was pumped up, and the waste oil was separated by the specific gravity difference in the waste oil separation tank. 20 g of this waste oil and fat was heated to 80 ° C. with stirring in a beaker, and 1 g of paraffin was added. When the waste oil mixed with paraffin was put into 200 g of cooling water stirred at 25 ° C., a solidified waste oil with a diameter of about 5 mm was obtained. The amount of hexane extracted from the obtained waste oil solidified product was measured and found to be 87.2%, and the total calorific value was measured by a thermal laboratory calorimeter to be 33300 J / g. The obtained results are summarized in Table 2.

Test example 3
A waste oil solidified product was obtained in the same manner as in Test Example 2 except that the paraffin was changed to stearic acid. The obtained results are summarized in Table 2.

Test example 4
Waste oil and fat solidified product was obtained in the same manner as in Test Example 2 except that the paraffin was changed to 12-hydroxystearic acid. The obtained results are summarized in Table 2.

Test Example 5
A waste oil solidified product was obtained in the same manner as in Test Example 2 except that the oil solidifying agent was not used. The obtained results are summarized in Table 2.

Test Example 6
The oil and fat solidifying agent was not added to the separated waste oil and fat, and analysis was performed without heating and stirring. The obtained results are summarized in Table 2.

  As can be seen from Table 2, the shape stability of the obtained waste oil solidified product was not good in Test Example 5 and Test Example 6 in which the oil fat solidifying agent was not used. In Test Example 6 in which heating and stirring were not performed, the hexane extraction ratio of the obtained waste oil solidified product was 51.5% by weight, indicating that the water content was high. On the other hand, in Test Examples 2 to 4 using 5 parts by weight of the fat / oil solidifying agent with respect to 100 parts by weight of the waste oil / fat, the shape stability of the obtained waste oil / fat solidifying agent was good. Moreover, all the hexane extraction ratio exceeds 80 weight%, and it turns out that the moisture content is considerably lower than Test Example 6. Furthermore, in Test Example 6, the total calorific value is 28900 J / g, whereas in Test Examples 2 to 4 both exceed 32300 J / g, indicating a total calorific value equal to or higher than that of coal / coke. It can be used as fuel.

It is explanatory drawing which shows the embodiment of the processing apparatus of the oil containing fat wastewater of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Sink 3 Waste water introduction pipe 4 Strainer 5 Grease trap 6 Oil containing fat waste water suction pipe 7 Waste oil fat separation tank 8 Valve 9 Heating tank 10 Stirring apparatus 11 Heater 12 Valve 13 Cooling water tank 14 Stirring apparatus 15 Waste oil solidified substance 16 Valve 17 Waste water supply pipe 18 Valve 19 Waste water return pipe 20 Cooling water 21 Cooling water storage tank 22 Valve 23 Cooling water supply pipe 24 Discharge pipe

Claims (10)

  A method for treating oil-containing fat wastewater, comprising solidifying the waste oil / fat by adding an oil / fat solidifying agent to waste oil / fat separated from oil-containing fat / oil wastewater collected in a grease trap.   The method for treating oil-containing fat wastewater according to claim 1, wherein the fat-solidifying agent is added, heated and then cooled.   The method for treating oil-containing fat wastewater according to claim 2, wherein waste oil heated to a temperature equal to or higher than the melting point of the oil-solidifying agent is charged into cooling water and cooled.   The method for treating oil-containing fat wastewater according to claim 3, wherein the difference between the temperature of the heated waste oil and fat and the temperature of the cooling water is in the range of 20 to 100 ° C.   The method for treating oil-containing fat wastewater according to any one of claims 1 to 4, wherein the oil-solidifying agent is an aliphatic compound having a melting point in the range of 40 to 100 ° C.   6. The method for treating oil-containing fat wastewater according to claim 5, wherein the fat-solidifying agent is at least one selected from the group consisting of stearic acid, 12-hydroxystearic acid and paraffin.   The method for treating oil-containing fat wastewater according to any one of claims 1 to 6, wherein the waste oil-and-fat solidified product has a hexane extract content in the range of 60 to 100% by weight.   Separation means for separating waste oil and fat from the oil-containing fat waste water accumulated in the grease trap, heating means for heating the waste oil and fat to the melting point of the fat and oil solidifying agent in the presence of the oil and fat solidifying agent, and cooling the heated waste oil and fat An oil-containing fat wastewater treatment apparatus comprising cooling means for solidifying the oily fat.   The apparatus for treating oil-containing fat wastewater according to claim 8, wherein the heating means is a heating tank provided with a heater and a stirring device, and the cooling means is a cooling water tank provided with a stirring device.   The apparatus for treating oil-containing fat wastewater according to claim 9, wherein the capacity of the cooling water tank is more than twice the capacity of the heating tank.

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