JP2002186960A - Method for treating vegetable oil waste liquid and method for preparing fertilizer using components obtained by its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reducing components contained in a vegetable oil waste liquid which deteriorates an environment and a method for reducing and making use of the vegetable oil waste liquid. SOLUTION: The method for treating the vegetable oil waste liquid comprises a process for freezing the vegetable oil waste liquid, a process for melting the frozen vegetable oil waste liquid and a process for separating and recovering a liquid phase generated in the melting process from a solid phase, wherein the recovery of the liquid phase is performed by sequentially separating the liquid phase generated in the melting process into a first melted portion and a second melted portion, and the content of at least one kind component of the group consisting of organic components and inorganic components contained in the vegetable oil waste liquid is reduced by recovering the second melted portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for treating vegetable oil waste liquid. Specifically, the method for treating a vegetable oil waste liquid of the present invention is a method for treating a vegetable oil waste liquid generated as a by-product when extracting a vegetable oil such as palm oil from a plant, which is contained in the vegetable oil waste liquid. And a method for reducing the content of at least one of the organic component and the inorganic component.

[0002] The present invention also relates to a method for producing fertilizer from vegetable oil waste liquor. Specifically, the method for producing a fertilizer from a vegetable oil waste liquid of the present invention relates to a method for producing a fertilizer using the components obtained in the above-described method for treating a vegetable oil waste liquid.

[0003] The present invention further relates to a method for recycling vegetable oil effluent. Specifically, the method for recycling a vegetable oil waste liquid of the present invention relates to a method for recycling a vegetable oil waste liquid by applying a fertilizer obtained by the method for producing a fertilizer from the vegetable oil waste liquid as a fertilizer for plant growth.

[0004]

2. Description of the Related Art The production area of oil palms, mainly in Malaysia, belongs to the tropics, and is characterized by the diversity of genetic resources and the high reaction activity due to high temperatures. In the coconut oil manufacturing process, a large amount of process water is used mainly for the purpose of washing the oil in the oil pressing process, and at the same time, a large amount of high-concentration waste liquid (coconut oil waste liquid) is discharged. Currently, coconut oil effluent is mainly treated in anaerobic treatment ponds called lagoons. It is not uncommon for lagoons to exceed 1 km in length, and the organic components of the effluent are ultimately reduced to methane by various microorganisms over a residence time of several months. Coconut oil effluents are generally highly polluting effluents with a COD of more than 50,000 ppm, but these polluting organic components are therefore indiscriminately released from the lagoon to the atmosphere. Furthermore, because of the completely natural waste liquid treatment method, treated water is often discharged into rivers with insufficient treatment.

On the other hand, in a palm oil factory, a large amount of solid waste such as fiber remaining after being squeezed from palm bunches and coconut is discharged, and the energy required in the factory is obtained by burning them. , There is more left. For this reason, an evaporation method for evaporating and treating the waste liquid itself has been attempted. However, because of the suspended solid content (hereinafter, also referred to as “SS”) exceeding 15,000 ppm contained in the coconut oil waste liquid,
There is a problem in removing residues remaining in the evaporator. Further, since the concentration of the organic component in the waste liquid is too high, even if the waste liquid is evaporated, the clarity of the condensed water is not high.

On the other hand, recently, the effect of coconut oil waste liquid as a fertilizer has been recognized, and an attempt has been made to recycle the waste liquid to an oil palm plantation. However, the amount of waste liquid is enormous, and the entire amount of waste liquid is recycled. It is difficult.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problem. Specifically, the present invention provides:
An object of the present invention is to provide a method for treating a vegetable oil waste liquid that can reduce the amount of components that can deteriorate the environment, such as organic components contained in the vegetable oil waste liquid. Another object of the present invention is to provide a method that can reduce the amount of waste vegetable oil waste and can use it effectively.

[0008]

That is, the present invention provides the following method for treating a vegetable waste liquid, a method for producing a fertilizer from a vegetable oil waste liquid, and a method for recycling a vegetable oil waste liquid.

(1) a step of freezing a vegetable oil waste liquid;
A method for treating a vegetable oil waste liquid, comprising: a step of melting the frozen vegetable oil waste liquid; and a step of separating and recovering a liquid phase generated in the melting step from a solid phase, wherein the liquid phase is collected by the melting step. The organic phase and the inorganic component contained in the vegetable oil waste liquid are collected by separating the liquid phase generated therein into a first-stage and a second-stage melt over time, and collecting the late-stage melt. The method for treating a vegetable oil waste liquid, wherein the content of at least one component of the group consisting of:

(2) The method for treating a vegetable oil waste liquid according to the above (1), wherein an organic component and an inorganic component contained in the vegetable oil waste liquid are solids dissolved in the vegetable oil waste liquid.

(3) The decision to start the fractionation of the late melt is selected from the group consisting of BOD value, COD value and nitrogen content, phosphorus content, potassium content and ammonia content. The method for treating vegetable oil waste liquid according to the above (1) or (2), wherein the method is performed using at least one value as an index.

(4) The pre-melted fraction is separated into first to n-th (n is a natural number of 1 or more) fractions over time,
The late melt is fractionated over time into (n + 1) -th to (n + m) -th (m is a natural number of 1 or more) fractions, and at least one of the n-th organic component and the inorganic component is contained. When the concentration of the seed component decreases to a concentration within the range of 30% to 100% of the concentration of the at least one component contained in the vegetable oil waste liquid before freezing, the (n-1) th The method for treating a plant waste liquid according to any one of the above (1) to (3), wherein the fraction is used as the first-stage melt, and the nth and subsequent fractions are collected as the second-stage melt.

(5) The method for treating a vegetable oil waste liquid according to any one of the above (1) to (4), wherein the step of separating the liquid phase from the solid phase is performed using a sieve having a mesh size of 40 to 400. .

(6) The method for treating a vegetable oil waste liquid according to any one of the above (1) to (5), wherein the vegetable oil waste liquid is a waste liquid produced in a step of producing coconut oil from palm.

(7) At least a part of the late smelt is subjected to a biological method including microbial treatment, a physicochemical method including activated carbon treatment, an evaporation method and a membrane separation method, and a subcritical chemical reaction and a supercritical chemical reaction. A reprocessing step by at least one of resource recycling of the waste liquid, reduction of organic components and inorganic components, and energy recovery from the waste liquid, which includes subjecting the waste liquid to at least one of treatments by a chemical method including a reaction. The method for treating a vegetable oil waste liquid according to any one of the above (1) to (6).

(8) The vegetable oil waste liquid is produced by extracting vegetable oil from a plant, and the combustion energy generated when burning the solid waste obtained after the extraction is converted into energy for freezing. The method for treating a vegetable oil waste liquid according to any one of the above (1) to (7), which is used for at least a part of and / or at least a part of the energy for each reprocessing described in the above (7).

(9) a step of freezing the vegetable oil waste liquid;
A step of thawing the frozen vegetable oil waste liquid, and a step of separating and recovering a liquid phase generated in the thawing step from a solid phase. A process performed by fractionating into a first-stage melt and a second-stage melt, and mixing only the next component a or the next component a with at least one of the component b and c. Thereby producing a fertilizer from a vegetable oil waste liquid: (a component) at least a portion of the solid phase obtained in the separation step, (b component) at least a portion of the pre-melt, (c component) At least a portion of late melt.

(10) A step of collecting a plant, a step of producing a vegetable oil from the collected plant, a step of collecting a vegetable oil waste liquid generated in the vegetable oil production step, and the step of collecting the vegetable oil waste liquid according to the above (9). A method for recycling a vegetable oil waste liquid comprising a step of using a fertilizer obtained by subjecting the fertilizer to a method for producing a fertilizer to be used as a fertilizer for growing the plant.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the method for treating a vegetable oil waste liquid of the present invention (hereinafter, also referred to as the "treatment method of the present invention") will be described in detail. As a vegetable oil waste liquid to which the treatment method of the present invention is applied, a palm oil waste liquid will be described below by way of example, but a vegetable oil waste liquid to which the treatment method of the present invention can be applied is not limited thereto. , Soybean,
Waste liquids generated in the process of producing plant-derived oils such as sesame, camellia, olives, peanuts, corn, cottonseed, rice bran, safflower, sunflower, etc., and wastewater from homes and business establishments. Or containing hydrocarbon products derived therefrom,
The present invention can also be applied to waste liquid generated in a liquor production process such as sake and wine.

The palm oil waste liquid refers to a by-product produced from a series of steps for obtaining palm oil by squeezing palm oil from coconut. Specifically, as shown in FIG. 2, palm oil is obtained by peeling the coconut palm and squeezing the fruit. From this process, by-products derived from the skin, by-products obtained in the purification step after pressing the fruit, by-products derived from the peel after pressing the fruit, and the like are generated. Vegetable oil waste liquor that can be treated by the method of the present invention is usually obtained by physically removing solids such as bunches and fibers from these by-products in the oil pressing step, and then washing with oil and water. Aqueous solution. This coconut oil waste liquid contains cellulose, hemicellulose, lignocellulose, etc. as suspended solids (SS),
It contains low molecular fatty acids (organic acids) as dissolved organic components and ammonia, phosphorus, potash, magnesium and the like as dissolved inorganic components.

Each step of the processing method of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram including the steps of the processing method of the present invention. As shown in FIG. 1, the treatment method of the present invention comprises a step of freezing a vegetable oil waste liquid and a step of thawing the frozen vegetable oil waste liquid, and separating and recovering a liquid phase generated in the thawing step from a solid phase. I do. The treatment method of the present invention utilizes the fact that a solid content can be efficiently separated by performing a freezing and thawing step to separate a solid phase and a liquid phase.

In the treatment method of the present invention, freezing conditions such as freezing means and time required for freezing are not particularly limited as long as the coconut oil waste liquid can be frozen. Thawing conditions such as thawing means and time required for thawing are not particularly limited as long as the frozen suspension can be thawed and the liquid phase generated during thawing can be separated into two or more melted components. Absent. For example, in the case of a coconut oil waste liquid of about 1 liter (hereinafter also referred to as “L”), the suspension is frozen by cooling at −2 ° C. to −20 ° C. for about 0.5 to 24 hours. After the heat treatment, it can be melted by heating at 10 ° C. to 80 ° C. for about 0.3 to 24 hours or by leaving it to stand, but is not limited to these ranges.

There is no particular limitation on the time from the end of freezing to the start of thawing, and the place to be thawed may be the frozen place or another place.

One of the features of the treatment method of the present invention is that the liquid phase generated in the melting step is separated and recovered from the solid phase. That is, in the treatment method of the present invention, the liquid phase generated in the melting step is separated into the first and second melts with time. In the first stage of the melting process, the organic component and the inorganic component contained in the waste liquid are contained at a high concentration, while the organic components contained in the second stage component which are separated over time are contained. The concentrations of the components and the inorganic components gradually decrease. Therefore, by removing the first-stage melt from the waste liquid, the content of the organic component and the inorganic component of the second-stage melt can be significantly reduced as compared with the content of the waste liquid as a raw material.

Here, the first-stage melt and the second-stage melt in the melting step will be described. The liquid phase generated at the time of melting in the melting step of the treatment method of the present invention is separated into two parts, an early melt and a late melt.

The switching between the pre-melted portion and the late-melted portion is performed by a desired degree of treatment, specifically, a reduction in the amount of organic and / or inorganic components contained in the waste liquid after the treatment of the present invention. It can be set appropriately according to the degree and the like. To give an example, the concentration of any one of the organic component and / or the inorganic component in the liquid phase to be melted is contained in the vegetable oil waste liquid used as a raw material after the start of melting. The melted amount until the concentration of the component is reduced to about the same, and the liquid phase subsequently melted can be defined as the late melted amount. As described above, the fraction obtained at the beginning of the melting step contains a high concentration of organic components and / or inorganic components, but the concentration of these components decreases as time passes. Therefore, by separating up to the melt that the concentration of a certain component is almost equal to the concentration of the plant waste liquid as the raw material as the first melt, the concentration of the component contained in the late melt is the raw material. The concentration can be lower than that in the plant waste liquid, and the object of the present invention can be achieved.

In the treatment method of the present invention, it is preferable that the early melt and the late melt are each further separated into one or more fractions over time. The total number of fractions to be separated can be appropriately set according to the amount of the vegetable oil waste liquid to be treated, the amount of dissolved solids in the waste liquid, and the amount of suspended solids.

Specifically, attention is paid to one component (component A) contained in the vegetable oil waste liquid, and the concentration of component A in each fraction is monitored. When the concentration of the A component in a certain fraction is reduced to 30% to 100% of the concentration of the A component in the vegetable oil waste liquid before the treatment, the subsequent fraction is regarded as a late melt, and the earlier fraction is used. Can be recovered as the above-mentioned melted amount.
However, when to start the late melt,
To what extent the concentration of the A component should be reduced,
It should be determined according to whether or not to reprocess the late-stage melt, and it is not limited to the above range.
For example, if it is necessary to meet legal standards such as COD values that can be discharged into a river or the like as a waste liquid, the COD value of the fraction to be collected is smaller than 30% of the vegetable oil waste liquid before treatment. The fraction obtained after this can be used as a late melt. On the other hand, when industrially useful components such as organic acids are recovered from the late-stage melt and recycled, the concentration of the vegetable oil waste liquid before treatment is larger than 100%, for example, 120%.
From the fraction of the degree, it can be made into a late melt. Also,
In consideration of the fact that the concentration distribution of each fraction is different depending on the component used as an index, it is preferable to determine at which point the amount of the melted portion is to be the previously melted portion.

In the treatment method of the present invention, a value such as a COD value or a BOD value can be used as an index of the content of the organic component. The measurement of the COD value and the BOD value can be performed by an ordinary method. In addition, as an index of the content of the inorganic component, the content of an inorganic component useful as a fertilizer component such as phosphorus, potassium, and ammonium can be used. The inorganic component can be measured, for example, by measuring the electrical conductivity of the melt.

In the treatment method of the present invention, the method of separating the solid phase and the liquid phase is not particularly limited as long as at least a part of the suspended solids (SS) in the waste liquid can be separated from the liquid phase. This can be carried out by placing the plant waste liquid on a sieve such as a net and collecting the liquid component dropped. The sieve used is S contained in coconut oil waste liquid.
It can be set appropriately according to the size of S, etc.
Usually, a mesh size of about 10 to 1000 can be used, and a mesh size of about 40 to 400 is preferable.

In the treatment method of the present invention, by recycling unnecessary portions of the late-stage melt that do not become resource energy as they are, the waste liquid is recycled, and the organic components and / or inorganic components contained in the treatment liquid are recycled. It is possible to further reduce the amount of components and recover energy from waste liquid.

Specifically, unnecessary parts that do not become resource energy are subjected to at least one of the following additional treatments: biological techniques including microbial treatment, activated carbon treatment, physical chemistry including evaporation and membrane separation. Techniques, including subcritical and supercritical chemical reactions.

As an example of the microorganism treatment, treatment by methane fermentation is also possible. By subjecting to the activated carbon treatment, residual organic substances can be adsorbed and removed.

By subjecting it to the evaporation method, most of the purified water and a small amount of concentrated waste liquid can be obtained. The treated water purified by this reprocessing can be used as process water in the vegetable oil production stage. In addition, the concentrated waste liquid can be recycled into the raw waste liquid and used again in the treatment method of the present invention. Since the treatment liquid to be subjected to this evaporation method has passed through the treatment method of the present invention, the S contained in the vegetable oil waste liquid
Most of S has already been removed. Therefore, there is an effect that maintenance and management of the evaporator, which has been a conventional problem, becomes extremely easy. The membrane separation method includes, for example, a treatment using a membrane such as an electrodialysis membrane or a reverse osmosis membrane.

In the treatment method of the present invention, at least one of the energy used for the freezing step and the energy for the above-mentioned additional treatment is used for producing solid waste such as tufts and berries generated as a by-product in the coconut oil production step. It is preferable to use combustion energy from the viewpoint of energy cost.

Next, the method of the present invention for producing a fertilizer from waste vegetable oil (hereinafter, also referred to as the “fertilizer production method of the present invention”) will be described in detail.

The method for producing a fertilizer of the present invention comprises the step of separating the liquid phase from the solid phase in the above-mentioned treatment method of the present invention. A fertilizer from a vegetable oil waste liquor by combining at least a part (component (b)) of the early melt in the treatment method and / or at least a part (component (c)) of the late melt in the treatment method of the present invention. is there.

The combination of the components a to c and the ratio of the components are not particularly limited, and are appropriately set according to the amount of SS contained in the solid phase to be formed, the amounts of organic and inorganic components in the melt, and the like. can do. In addition, the component a may be at least a part of the solid phase obtained by the treatment method of the present invention, but is preferably the whole amount from the viewpoint of the effectiveness of the fertilizer.

As described above, the solid phase obtained in the solid-liquid separation step contains the solids suspended in the coconut oil waste liquid such as cellulose, hemicellulose, and lignocellulose, and the organic matter dissolved in the coconut oil waste liquid. It contains organic substances such as acids and inorganic substances such as ammonia, phosphorus, potassium, and magnesium. Among these components, in particular, ammonia, phosphorus,
Potash is a component useful as a fertilizer (hereinafter, also referred to as “fertilizer active ingredient”).

The fertilizer produced by the fertilizer production method of the present invention can be used to reduce the concentration of the fertilizer active ingredient contained in the fertilizer by using the above-mentioned component b. Can be significantly higher than the concentration of

By applying the fertilizer produced by the fertilizer production method of the present invention as a fertilizer for cultivating plants such as coconut oil plantations, vegetable oil waste liquid can be recycled. The embodiment of recycling such a vegetable oil waste liquid is also included in the present invention.

As described above in the section of the prior art, the amount of coconut oil waste liquid is enormous in volume, and it has been difficult to recycle the entire waste liquid. On the other hand, the fertilizer obtained by applying the fertilizer recycling method of the present invention to an oil palm has a significantly higher concentration of the active ingredient of the fertilizer than untreated palm oil conventionally used as a fertilizer. Therefore, the amount of waste liquid that can be recycled can be increased, so that the waste portion can be reduced and the waste liquid can be used effectively. Furthermore, the amount of waste can be reduced, and adverse effects on the natural environment can be suppressed.

[0043]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1 A coconut oil waste liquid was obtained from a coconut oil factory located in Denkir, Kuala Lumpur, Malaysia. Put this in a certain amount (200g) cup, -20 ℃
In a freezer overnight. The next morning, the frozen palm oil waste was placed on a 400 mesh plastic sieve and thawed at room temperature (25 ° C.). From the start of melting, the amount of each fraction of the melt was divided into 9 fractions of 20 to 25 mL each.

Table 1 below shows the COD value, TS (total solid content) and SS (suspended solid content) concentration for each fraction. Total COD in coconut oil waste liquid used as raw material is 30900mg / L, TS
Was 45180 mg / L and SS was 17500 mg / L.

[0046]

[Table 1]

As shown in Table 1, the COD values of the first to third fractions were higher than the COD values of the coconut oil waste liquid as the raw material. The first to third fractions were collected as the first-stage melt, and the fourth to ninth fractions were collected as the second-stage melt. The COD (51700 mg / L) of the melted product in the previous period was about 1.7 times the COD of the coconut oil waste liquid. In addition, these 1-3 fractions and S
By mixing the S residue, it can be used as a concentrated liquid fertilizer.

Example 2 Another coconut oil waste liquid (200 mL, CO
D: 24900 mg / L), cooled to −20 ° C. and melted at room temperature in the same manner as in Example 1. Table 2 shows the CO for each fraction.
The D value, the concentration of TS (total solid content) and the concentration of SS (suspended solid content) are shown.

[0049]

[Table 2]

As shown in Table 2, the COD values of the first to third fractions were higher than the COD values of the coconut oil waste liquid as the raw material. Up to these third fractions are the above-mentioned melts,
By recovering the fourth to ninth fractions as late melts,
The amount of organic components in the coconut oil waste liquid can be significantly reduced.

Example 3 Another coconut oil waste liquid (200 mL, CO
D: 274000 mg / L) and thawed at room temperature in the same manner as in Example 1 except that the mixture was frozen at -80 ° C. Table 3
Shows the COD value, TS (total solid content) and SS (suspended solid content) concentration for each fraction.

[0052]

[Table 3]

As shown in Table 3, the COD values of the first to fourth fractions were higher than the COD values of the coconut oil waste liquid as the raw material. Up to these fourth fractions are the melts in the previous period,
By recovering the 5th to 9th fractions as late melts,
The amount of organic components in the coconut oil waste liquid can be significantly reduced.

(Embodiment 4) Although the embodiments on a relatively small scale have been described above, the treatment method of the present invention, the fertilizer production method of the present invention, and the recycling method of the present invention are particularly applicable to palm oil plantations. It is useful when applied to palm oil wastewater discharged from a nearby palm oil manufacturing plant.
FIG. 2 shows a material balance when these methods of the present invention are applied to a waste liquid or the like discharged from a plant that manufactures coconut oil from coconut oil obtained from coconut oil plantations.

As shown in FIG. 2, by applying each method of the present invention to an actual coconut oil plantation, by-products generated from a coconut oil factory that have been conventionally discarded and may have an adverse effect on the environment. The material can be turned into resources such as fertilizer, and the waste can be brought into a state that does not adversely affect the environment. In addition, the energy for carrying out each method of the present invention can use the combustion energy of waste, so that the energy cost for carrying out the method can be kept low.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a process of the present invention.

FIG. 2 is a diagram illustrating a material balance in a standard coconut oil factory.

Claims (10)

[Claims] 1. A method for treating a vegetable oil waste liquid comprising the steps of freezing a vegetable oil waste liquid, melting the frozen vegetable oil waste liquid, and separating and recovering a liquid phase generated in the thawing step from a solid phase. The recovery of the liquid phase is performed by separating the liquid phase generated during the melting step into a first-stage melt and a second-stage melt over time, and collecting the late-stage melt. A method for treating a vegetable oil waste liquid, wherein the content of at least one component selected from the group consisting of an organic component and an inorganic component contained in the vegetable oil waste liquid is reduced by the method. 2. The method for treating a vegetable oil waste liquid according to claim 1, wherein the organic component and the inorganic component contained in the vegetable oil waste liquid are solids dissolved in the vegetable oil waste liquid. 3. The determination of when to start fractionation of the late smelt comprises determining the BOD value, the COD value and at least one selected from the group consisting of nitrogen, phosphorus, potassium and ammonia contents. 3. The method for treating a vegetable oil waste liquid according to claim 1, wherein the method is performed using one value as an index. 4. The method according to claim 1, wherein the first melt is a first to an n-th (n
Is a natural number of 1 or more), and the late melted fraction is (n + 1) th to (n + m) th (m is 1).
(Natural number above), and the concentration of at least one of the organic component and the inorganic component contained in the n-th organic compound and the at least one component contained in the vegetable oil waste liquid before freezing is determined. When the concentration falls to a concentration within the range of 30% to 100% of the concentration of the component, the fraction up to the (n-1) th is regarded as the pre-melted fraction, and the fraction after the n-th fraction is regarded as the latter. The method for treating a plant waste liquid according to any one of claims 1 to 3, which is recovered as a melt. 5. The method for treating a vegetable oil waste liquid according to claim 1, wherein the step of separating the liquid phase from the solid phase is performed using a sieve having a mesh size of 40 to 400. 6. The method for treating a vegetable oil waste liquid according to claim 1, wherein the vegetable oil waste liquid is a waste liquid generated in a step of producing coconut oil from palm. 7. A method in which at least a part of the late melt is subjected to a biological technique including a microbial treatment, a physicochemical technique including an activated carbon treatment, an evaporation method and a membrane separation method, and a subcritical chemical reaction and a supercritical chemical reaction. Recycling of waste liquid, including subjecting it to at least one method of treatment by chemical methods, including:
The method for treating a vegetable oil waste liquid according to any one of claims 1 to 6, further comprising a reprocessing step of reducing at least one of an organic component and an inorganic component and recovering energy from the waste liquid. 8. The vegetable oil waste liquid is produced by extracting vegetable oil from a plant, and the combustion energy generated when burning the solid waste obtained after the extraction is converted into the energy for freezing. The method for treating a vegetable oil waste liquid according to any one of claims 1 to 7, wherein the method is used for at least a part and / or at least a part of energy for each reprocessing described in the above (7). 9. A step of freezing a vegetable oil waste liquid, a step of thawing the frozen vegetable oil waste liquid, and a step of separating and recovering a liquid phase generated in the thawing step from a solid phase,
Recovering the liquid phase, comprising a step in which the liquid phase generated during the melting step is separated by time into a first-stage melt and a second-stage melt, and only the next component a, or A method for producing a fertilizer from a vegetable oil waste liquid by mixing the following component a with at least one of the components b and c: (a component) at least a part of the solid phase obtained in the separation step, (b component) at least a part of the early melt, and (c) at least a part of the late melt. 10. The method according to claim 9, wherein a step of collecting a plant, a step of producing vegetable oil from the collected plant, a step of collecting a vegetable oil waste liquid generated in the vegetable oil production step, and the step of collecting the vegetable oil waste liquid are described in claim 9. A method for recycling a vegetable oil waste liquid comprising a step of using a fertilizer obtained by subjecting the fertilizer to a method for producing a fertilizer as a fertilizer for growing the plant.