JP2012152675A - Organic waste liquid treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To biologically and efficiently treat organic waste liquid containing high concentration of sodium chloride and having high pH at a low cost to cause methane fermentation and to utilize gaseous methane as valuables.SOLUTION: A diluting step for diluting the organic waste liquid containing high concentration of sodium chloride and having high pH, an acid fermentation step in which the organic waste liquid in which sodium chloride concentration is diluted is subjected to acidic fermentation, a neutralization step for neutralizing the organic waste liquid subjected to the acidic fermentation, and a methane fermentation step in which the organic waste liquid whose pH becomes 5.5 to 8.5 by the neutralization is subjected to methane fermentation are carried out in series.

Description

  The present invention relates to a method for treating a high-concentration sodium chloride-containing, high-pH organic waste liquid, and relates to a technique of fermenting the organic waste liquid as a valuable resource by methane fermentation.

  For example, waste liquids in the soap manufacturing industry contain organic substances such as glycerin and fatty acids. Conventionally, these waste liquids have been discarded after recovering and regenerating valuable organic substances. However, in recent years when glycerin as a by-product of biodiesel production is distributed in large quantities, the recovery of glycerin from waste liquid has become unsuitable for cost, and in recent years, disposal of such waste liquid by incineration etc. has become the mainstream. It has become to.

  However, when such a treatment is performed, it has been studied to effectively use the organic matter in the waste liquid for reasons such as high energy waste and high environmental load. Except for recovery and regeneration, it is possible to recover energy as methane gas using methane fermentation by microorganisms, except for recovery and regeneration. However, it is not preferable as an environment in which microorganisms that perform methane fermentation are active, and there is a situation that it cannot be applied to the waste liquid in the soap manufacturing industry.

  In the present invention, explanation will be given mainly using soap production waste liquid as an example, but various industrial waste liquids such as biodiesel manufacturing industry also have similar problems, and it is considered to generate methane from organic substances in the waste liquid. (Patent Document 1). In the present invention, these waste liquids are collectively referred to as organic waste liquids.

The UASB method (Upflow Anaerobic Sludge Blanket) is known as a method for methane fermentation, and the UASB anaerobic treatment apparatus has a high sludge retention concentration and high load treatment. Since it is possible, in recent years it has spread rapidly, especially in food wastewater. In the UASB method, raw water is introduced in an upward flow from the lower part of the reaction tank, and sludge is sludge bed of granulated sludge having a particle diameter of 1 to several mm by using sludge blocked or granulated without using a bacterial adhesion carrier ( Sludge blanket), and a high-concentration microorganism is retained in the reaction tank to perform a high-load treatment. Compared with the aerobic activated sludge method, the organic substance load per reaction tank volume is 10 kg-CODCr / It is very high at m ³ / day or more. In addition, it also has excellent features such as no energy for aeration; energy recovery as methane gas; small amount of excess sludge generation;

  Acid fermentation is the decomposition of organic substances by acid-producing bacteria in an anaerobic state where oxygen is not present. In other words, according to acid fermentation, organic substances are reduced in molecular weight by hydrolysis and deamination of enzymes produced by acid-producing bacteria in the absence of oxygen, and organic acids, alcohols, ammonia and the like are generated. Such acid fermentation is usually performed as a pretreatment of methane fermentation treatment for the purpose of solubilization of sludge, fermentation treatment of oil, and the like (see Patent Documents 2 and 3).

JP 2003-027075 A JP 2000-237787 A JP 2000-271598 A

  In view of the above circumstances, an object of the present invention is to biologically treat an organic waste liquid containing high-concentration sodium chloride and having a high pH inexpensively and efficiently, and methane-fermenting it to use it as a valuable resource.

The acid-producing bacteria that perform acid fermentation are not special bacteria, but are facultative and absolute anaerobic bacteria that are widely distributed in the natural environment, and obtain energy necessary for growth by acid fermentation. Such acid fermentation produces an organic acid.
Here, as an acid-producing bacterium that performs acid fermentation, various bacteria used in normal anaerobic treatment can be used, for example, Bacillus, Clostridium, Lactobacillus, Bacteroides, Vibrio, Staphylococcus, Examples include Micrococcus genus, Butyribibrio genus, Fusobacterium genus, Enterobacter genus, Streptococcus genus, Peptococcus genus and the like. For example, in Clostridium sp. formicoacetium, C.I. butyricum ATCC 6014, C.I. thermoacetium, C.I. thermocellum, C.I. thermohydro-sulfuricum, etc .; in Lactobacillus sp. casei IFO 3914, L.C. It is known that bacteria such as brevis IFO 13109 are used. As these microorganisms, for example, cells contained in sewage sludge or the like in a sewage treatment plant can be used as they are.

  In addition, the methanogen that performs methane fermentation is not particularly limited. For example, bacteria belonging to the genus Methanobacterium, the genus Methanococcus, the genus Methanocarcina, the genus Methanosaeta, the genus Methanogenium, and the genus Methanospirilum are preferably used.

[Configuration 1]
In order to achieve the above object, the characteristic configuration of the organic waste liquid treatment method of the present invention is:
A dilution step for diluting a high pH organic waste liquid containing high concentration sodium chloride;
An acid fermentation process in which the organic waste liquid in which the sodium chloride concentration is diluted in the dilution process is acid-fermented;
A neutralization step of neutralizing the organic liquid waste acid fermented in the acid fermentation step to a pH of 5.5 to 8.5;
A methane fermentation step for methane fermentation of the organic waste liquid having a pH of 5.5 to 8.5 in the neutralization step;
The point is to perform in order.

[Operation effect 2]
When diluting organic waste liquid containing high concentration sodium chloride and high pH, the sodium chloride concentration (hereinafter simply referred to as salt concentration), which is undesirable for the growth of microorganisms, is reduced to a concentration at which microorganisms exhibit methane fermentation activity. Can be made.

  When the organic waste liquid in which the sodium chloride concentration is diluted in the dilution process is acid-fermented by the acid fermentation process, the acid-producing bacteria assimilate the organic matter in the organic waste liquid, and the organic waste liquid is acid-fermented. While making it fluid, the organic substance contained can be made suitable for methane fermentation. Moreover, the acid produced | generated by acid fermentation also plays the role which relieve | moderates the high pH conditions of the said organic waste liquid.

  When the organic waste liquid acid-fermented in the acid fermentation process is neutralized to pH 5.5 to 8.5 by the neutralization process, the neutralized organic waste liquid is adjusted to an environment suitable for the growth of methanogens. . If the neutralization treatment is carried out at a pH of 5.5 to 8.5, it is difficult for microorganisms to interfere with the activity of the microorganisms, and even if the pH of the organic waste liquid further fluctuates due to the action of the microorganisms, an appropriate microorganism growth environment is maintained. Therefore, it is preferable. Here, since the organic waste liquid has undergone an acid fermentation process, the organic matter has been moderately reduced in molecular weight and digested to the conditions under which methane fermentation is efficiently performed. It can be carried out.

  Specifically, after the dilution step, without performing the acid fermentation step, if the organic waste liquid just neutralized by the neutralization step is subjected to the methane fermentation step, acid fermentation that lowers the pH and decomposition of the organic acid Since methane fermentation that raises the pH occurs simultaneously, the pH tends to become unstable, and it is difficult to cause methane fermentation stably. It was found that by using the organic waste liquid that has undergone the acid fermentation process for the methane fermentation process, the pH can be stabilized and methane fermentation can be performed satisfactorily.

[Configuration 2]
Moreover, it is preferable to perform the aerobic treatment process which decomposes | disassembles the organic waste liquid methane-fermented in the said methane fermentation process by an aerobic microbe further.

[Operation effect 2]
Even if the organic matter is methane-fermented and converted into methane gas in the methane fermentation process, the organic matter that could not be treated actually remains in the organic waste liquid. Therefore, if these organic substances are decomposed by aerobic bacteria to convert the remaining organic matter into carbon dioxide and water, it is only necessary to discharge only a relatively clean organic wastewater with a low environmental load. Therefore, the organic waste liquid processing apparatus which can process an organic waste liquid further highly according to an aerobic treatment process was able to be provided.

[Configuration 3]
Moreover, the neutralization process can be performed by mixing the organic waste liquid obtained in the aerobic treatment process with the organic waste liquid subjected to the acid fermentation in the acid fermentation process.

[Operation effect 3]
The organic waste liquid that has undergone the acid fermentation process is usually acidic. On the other hand, the organic waste liquid that has undergone the aerobic treatment process is usually made alkaline by an alkali or the like added to neutralize the organic waste liquid that has undergone the acid fermentation process. Therefore, in the neutralization process, when the organic waste liquid obtained in the aerobic treatment process is used to neutralize the acidic organic waste liquid that has undergone the acid fermentation process, the amount of alkali to be used in the neutralization process is reduced. The amount of acidic substances required for the neutralization process can be reduced even when neutralization is performed to make the liquidity of the organic waste liquid that has undergone the aerobic treatment process discharged to the outside harmless. Can be reduced.

[Configuration 4]
Moreover, the organic waste liquid before acid fermentation can be mixed with the organic waste liquid acid-fermented in the acid fermentation process to perform the neutralization process.

[Operation effect 4]
As described above, the organic waste liquid that has undergone the acid fermentation step is usually acidic. On the other hand, the organic waste liquid before acid fermentation has a high pH. Accordingly, in the neutralization step, the amount of acid to be used in the neutralization step is reduced by using the organic waste solution before acid fermentation to neutralize the acidic organic waste solution that has undergone the acid fermentation step. A neutralization step can be performed. At this time, the organic waste liquid before the acid fermentation may be either before dilution or after dilution, in order to avoid the influence of salt concentration in the subsequent steps. It is preferable to use diluted organic waste liquid. In addition, since the organic waste liquid used here will be used for the methane fermentation process without passing through the acid fermentation after the neutralization process, the amount used is limited and set in consideration of the pH fluctuation in the methane fermentation process. It is desirable to do.

[Configuration 5]
In the dilution step, the organic waste liquid is preferably diluted so that the sodium chloride concentration is 2.0% or less.

[Operation effect 5]
The anaerobic bacteria used in normal UASB do not show very high activity in an environment with a high salt concentration, but as a result of the study by the present inventors, methane is sufficient in a low salt concentration environment of about 2.0% or less. It is clear from the examples described later that the fermentation activity is exhibited. Therefore, when the organic waste liquid is diluted so that the sodium chloride concentration is 2.0% or less in the dilution section, the methane fermentation process is performed with highly active UASB, and methane can be generated.

[Configuration 6]
In order to achieve the above object, the characteristic configuration of the organic waste liquid treatment apparatus of the present invention is:
A dilution section for diluting high-concentration sodium chloride-containing, high-pH organic waste liquid,
An acid fermentation part for acid fermentation of the organic waste liquid in which the sodium chloride concentration is diluted in the dilution part,
A neutralization treatment unit for neutralizing the organic waste liquid acid-fermented in the acid fermentation unit to a pH of 5.5 to 8.5;
A methane fermentation unit for methane fermentation of an organic waste liquid having a pH of 5.5 to 8.5 in the neutralization unit,
The gas consumption part which consumes the methane gas obtained in the said methane fermentation part as a fuel is provided.

[Operation effect 6]
According to the organic waste liquid treatment apparatus, the dilution process in the organic waste liquid treatment method described above can be performed in the dilution section, the acid fermentation process can be performed in the acid fermentation section, and the neutralization process is performed in the neutralization section. The methane fermentation treatment can be performed in the methane fermentation section. That is, according to the organic waste liquid treatment apparatus, highly efficient organic waste liquid treatment in the above-described organic waste liquid treatment method can be performed. Moreover, since the gas consumption part is provided, the methane gas produced | generated in this way can be consumed effectively.

[Configuration 7]
Moreover, you may provide the waste_water | drain supply part which supplies low concentration sodium chloride containing waste_water | drain to the said dilution part.

[Operation effect 7]
In an environment where organic waste liquid containing high concentration sodium chloride and high pH is generated, wastewater containing low concentration sodium chloride is often generated at the same time. By combining these organic waste liquid and organic wastewater, it becomes possible to efficiently supply the organic matter in the wastewater to the methane fermentation treatment department, and produce valuable materials while effectively using the organic matter contained in the wastewater. This makes it possible to treat two types of organic waste liquid and organic waste water at the same time, which is efficient.

[Configuration 8]
The low-concentration sodium chloride-containing waste water may be a mixed waste water of cooling water or washing waste water in the soap production salting-out step.

[Operation effect 8]
For example, in the soap manufacturing industry, organic wastewater having a low salt concentration is generated as cooling water or washing wastewater in each process. Since the waste water of such a soap production facility contains organic matter at a high concentration, the salt concentration is low, and the pH is close to neutral, so it is suitable for supplying to the dilution section as the low concentration sodium chloride-containing waste water.

[Configuration 9]
The organic waste liquid may be a waste liquid from a salting-out step in soap production.

[Effect 9]
In the soap manufacturing industry, high-concentration sodium chloride-containing, high-pH organic waste liquid is generated in the salting-out process, and high-concentration organic substances are contained. It is suitable as a waste liquid to be treated. In addition, in the soap manufacturing industry, when combined with organic wastewater with low salt concentration generated as cooling water or washing wastewater in each process, it is possible to produce valuable materials with extremely high efficiency and effective use of wastewater from soap manufacturing facilities. it can

[Configuration 10]
Moreover, it is preferable that the said methane fermentation part is equipped with the UASB reaction tank which performs methane fermentation by UASB method.

[Operation effect 10]
As a biological treatment method, methane can generally be produced by an anaerobic treatment method, so any form may be adopted as the methane fermentation part, but when the UASB method is adopted as the methane fermentation part, It is suitable because it has a high methane conversion capacity with respect to the amount of organic matter and a high reaction treatment speed.

  The composition of waste water in the soap manufacturing industry is roughly as shown in Table 1. The high-concentration waste water in the table corresponds to waste water in the salting-out process, and is referred to as organic waste liquid in the present invention. On the other hand, low-concentration wastewater corresponds to wastewater generated as cooling water or washing wastewater in each process, and is referred to as organic wastewater in the present invention. For reference, the physical properties of wastewater in the biodiesel fuel manufacturing industry are also shown in Table 1.

1 is an overall view of an organic waste liquid treatment apparatus of the present invention. It is a figure which shows the relationship between the salt concentration and methane conversion rate in each experiment example.

  FIG. 1 shows an example of the organic waste liquid treatment apparatus of the present invention. In addition, the organic waste liquid processing apparatus shown below is an illustration for specifically explaining the present invention, and the present invention is not limited to this description, and is within a range not departing from the gist of the present invention. Needless to say, various configurations can be changed and added.

  As shown in FIG. 1, the organic waste liquid treatment apparatus of the present invention includes an organic waste liquid storage unit 1, an organic waste water storage unit 2 that functions as a waste water supply unit, a dilution unit 3, an acid fermentation unit 4, a neutralization processing unit 5, and methane. The fermenting unit 6, the gas consuming unit 7, and the aerobic processing unit 8 are provided, and for example, the soap manufacturing waste liquid as the organic waste liquid 1a is processed.

  The said organic waste liquid storage part 1 consists of the tank 10 which stores the organic waste liquid 1a, for example, temporarily stores the waste liquid of the salting-out process in a soap manufacturing plant as the organic waste liquid 1a. As shown in Table 1, the organic waste liquid 1a usually contains high-concentration sodium chloride and has a high pH, and contains high-concentration glycerin as an organic substance (CODCr 40000 to 120,000 mg / L). .

  Moreover, the said organic waste_water | drain storage part 2 consists of the tank 20 which stores the organic waste_water | drain 2a, for example, temporarily stores the waste_water | drain generate | occur | produced as the cooling water in each process in a soap manufacturing plant, or washing | cleaning waste_water | drain 2a. As shown in Table 1, this organic waste water 2a usually contains almost no sodium chloride, is almost neutral, and contains glycerin as an organic substance (CODCr 100 to 5000 mg / L or so).

  The dilution section 3 includes a dilution tank 30 that receives the organic waste liquid 1a from the organic waste liquid storage section 1 and dilutes with the organic waste water 2a from the organic waste water storage section 2, and has a salt concentration in the dilution tank 30. A dilution step in which the diluted organic waste liquid 3a is discharged out of the dilution tank 30 by mixing and diluting so that becomes a predetermined value (for example, 2.0%) or less (more preferably, 1.5% or less). It is configured so that it can be performed.

  The acid fermentation unit 4 includes an acid fermentation tank 40 for acid fermentation of the organic waste liquid 3a from the dilution unit 3, and the acid fermentation tank 40 includes a supply unit 41 that receives the organic waste liquid 3a, and has been subjected to acid fermentation. A discharge unit 42 for discharging the organic waste liquid 4a is provided. The acid fermentation unit 4 contains sludge mainly composed of facultative anaerobic bacteria (acid-producing bacteria) and acid ferments the organic waste liquid 4a in the acid fermentation tank to produce an organic acid such as acetic acid. It is the structure which can perform a fermentation process.

  The neutralization processing unit 5 includes a supply unit 51 for supplying the organic waste liquid 4a to the reaction tank 50 for the neutralization reaction process for neutralizing the organic waste liquid 4a, and an alkali (for example, an aqueous sodium hydroxide solution) 5b. An alkali addition unit 52 for charging is provided, and a neutralization step of receiving and mixing and reacting with the organic waste liquid 4a from the acid fermentation unit 4 can be performed. In order to maintain a predetermined reaction efficiency, this reaction can be promoted by a neutralization reaction by adding the alkali 5b from the alkali adding section 52. When the pH in the reaction tank 50 falls within a predetermined range (for example, pH 5.5 to 8.5), the neutralized organic waste liquid 5a can be discharged from the waste liquid discharge unit 53 to the outside of the reaction tank 50. .

  As shown in FIG. 1, the methane fermentation unit 6 includes the UASB reaction tank 60, and the UASB reaction tank 60 is sludge granulated mainly with anaerobic bacteria (UASB bacteria) at the bottom. And an organic waste liquid supply unit 62 that disperses and supplies the organic waste liquid 5a discharged from the neutralization processing unit 5. As a result, an upward flow of the introduced organic waste liquid 5a is formed, and circulation of the internal organic waste liquid 5a is promoted, and a methane fermentation process is performed in which organic matter is methane-fermented by the flowing granules 60a. On the upper part of the sludge bed 61, there is provided a separation plate 63 for preventing the granule 60a from flowing out and for transferring the treated supernatant and the generated methane gas 6b upward. The treated organic waste liquid 6a transferred to the upper side of the separation plate 63 is taken out of the UASB reaction tank 60 from the overflow part 64, and the generated methane gas 6b is taken out of the UASB reaction tank 60 from the gas recovery part 65. It has a configuration. The overflow section 64 is provided with a circulation processing liquid circulation path 66 for circulating a part 6c of the organic waste liquid to the organic waste liquid supply section 62, and an appropriate liquid line velocity in the tower is maintained while maintaining a necessary residence time. It can be set to a value. The liquid line velocity in the column is about 3 m / h because if the granule 60a is too fast, the granule 60a will be worn out or will flow out. If it is too slow, the decomposition rate will be slow, and suspended substances other than granules will tend to accumulate. It is preferable.

  The gas consumption unit 7 includes a fuel gas supply unit 70 that mixes the combustible gas 7a together with the methane gas 6b recovered from the gas recovery unit 65 and supplies the fuel gas as a fuel gas. And a boiler that generates power 7b, an engine, a turbine, and the like. The steam and power 7b generated here are used as, for example, a heat source or power source of a soap production plant and are effectively used.

  The aerobic treatment unit 8 can be applied to various known wastewater treatment tanks such as an activated sludge tank and a contact aeration tank, and the organic waste liquid 6a supplied from the methane fermentation unit 6 is further subjected to aerobic decomposition treatment to be clean. The drainage 8a is configured to be discharged.

  In addition to the alkali addition unit 52, the neutralization processing unit 5 supplies a part of the organic waste liquid 3b diluted in the dilution unit directly from the bypass 31 without passing through the acid fermentation unit 4. The organic waste liquid 4a subjected to the acid fermentation can be neutralized by substituting a part or all of the alkali 5b to be supplied from the alkali addition part 52 with a part 3b of the organic waste liquid. It is.

  Similarly, the neutralization processing unit 5 is provided with a drainage return unit 55 for supplying a part of the drainage 8b from the aerobic processing unit 8 through the return path 81, and for the alkali 5b to be supplied from the alkali addition unit 52. The organic waste liquid 4a subjected to the acid fermentation may be configured to be neutralized by substituting a part or all of the waste water with a part 8b of the waste water.

  Below, the experiment example which examined the methane production | generation efficiency at the time of supplying a specific waste liquid to the said organic waste liquid processing apparatus is shown. The following experimental examples are for specifically illustrating the present invention, and the present invention is not limited to the following examples.

[Experimental example]
As simulated organic waste liquid and simulated organic waste water, organic waste liquid and organic waste water having the following properties were prepared.

Organic waste liquid:
CODCr: 130000 (mg / L)
Salt concentration: 9.9 (%)
pH: 12

Organic wastewater:
CODCr: 500 (mg / L)
Salt concentration: 0 (%)
pH: 7.2

[Experiment 1]
The organic waste liquid was neutralized to pH 7.5 by adding sulfuric acid, and then mixed with the organic waste water so that the volume ratio was 1: 9. 8 mL of the obtained mixed solution was taken in a 200 mL volume vial, 10 mL of UASB reactor sludge was added, the gas phase portion was replaced with nitrogen, sealed, and cultured at 55 ° C. for 13 days. As a result of collecting the gas in the gas phase part of the vial after incubation and measuring the amount and the methane gas concentration, it was revealed that 99.9% of the added COD was converted to methane.

[Experiment 2]
An experiment similar to Experiment 1 was performed except that 4 mL of a mixed solution obtained by mixing organic wastewater after neutralization in Experiment 1 with a volume ratio of 1: 4 was placed in a 200 mL vial. As a result, it was revealed that 90.1% of the added COD was converted to methane.

[Experiment 3]
The same experiment as in Experiment 1 was performed except that 1.6 mL of a mixed solution obtained by mixing organic wastewater after neutralization in Experiment 1 with a volume ratio of 1: 1 was taken in a 200 mL vial. . As a result, it was revealed that 63.7% of the added COD was converted to methane.

[Experiment 4]
The same experiment as in Experiment 1 was performed except that 0.8 mL of only the organic waste liquid after neutralization in Experiment 1 was taken in a 200 mL vial. As a result, it was revealed that 28.1% of the added COD was converted to methane.

  The results of Experiments 1 to 4 are plotted as horizontal axis: salt concentration (%) and vertical axis: methane conversion rate (%) as shown in FIG.

From FIG. 2, when diluting the organic waste liquid in the present invention with the organic waste water, if the salt concentration is diluted to 2.0% or less, a high methane conversion rate can be realized with a small dilution rate. It was suggested that it is desirable to further dilute the salt concentration to 1.5% or less.
[Example of actual operation]
The organic waste liquid treatment apparatus shown in FIG. 1 was supplied with organic waste liquid and organic waste water in the soap manufacturing industry shown in Table 1.

  The dilution process in the dilution unit 3 is performed by diluting the organic waste liquid 1a with 50t and the organic waste water 2a with 280t to dilute the salt concentration to about 15000mg / L, pH12, and COD to about 10000Cr (mg / L). Organic waste liquid 3a could be obtained.

  Next, when the acid fermentation process in the acid fermentation unit 4 was performed, the pH of the charged organic waste liquid 3a was reduced to about 5, and it was found that the organic waste liquid 4a having a reduced molecular weight was obtained.

  Next, in the neutralization process in the neutralization processing unit 5, a part 3b of the diluted organic waste liquid is added to neutralize the organic waste liquid 4a, and the final pH is added to the alkali (sodium hydroxide) 5b. To a target pH of 7.

  When the obtained organic waste liquid 5a is subjected to a methane fermentation process in the methane fermentation unit 6, it produces methane gas 6b without causing fermentation inhibition and is supplied to the gas consumption unit 7 to be converted into steam or power 7b for effective use. We were able to.

  Moreover, the organic waste liquid 6a which flows out from this methane fermentation process was about pH 7. The organic waste liquid 6a was subjected to an aerobic treatment step by the aerobic treatment unit 8, and further, clean waste water 8a from which organic substances were removed could be obtained. The pH of the waste water 8a was about 9, and it could be neutralized and discharged to the outside by adding an acid (such as sulfuric acid).

  In the present embodiment, the target pH value in the neutralization processing unit 5 is set to 5.5 to 8.5, but is not limited thereto, and can be appropriately changed according to the properties of the organic waste liquid. The same applies to the salt concentration in the dilution section 3.

DESCRIPTION OF SYMBOLS 1: Organic waste liquid storage part 1a: Organic waste liquid 10: Tank 2: Organic waste water storage part 2a: Organic waste water 20: Tank 3: Dilution part 3a: Organic waste liquid 3b: Part of organic waste liquid 30: Dilution tank 31: Bypass path 4 : Acid fermentation section 4a: Organic waste liquid 40: Acid fermentation tank 41: Supply section 42: Discharge section 5: Neutralization processing section 5a: Organic waste liquid 5b: Alkali 50: Reaction tank 51: Supply section 52: Alkali addition section 53: Waste liquid Discharge unit 54: Stock solution supply unit 55: Waste water return unit 6: Methane fermentation unit 6a: Organic waste solution 6b: Methane gas 6c: Part of the organic waste solution 60: UASB reaction tank 60a: Granule 61: Sludge bed 62: Organic waste solution supply unit 63: Separator plate 64: Overflow part 65: Gas recovery part 66: Circulating process liquid circulation path 7: Gas consumption part 7a: Combustible gas 7b: Steam and power 70: Fuel gas supply Part 8: aerobic treatment unit 8a: drainage 8b: Some drainage 81: return path

Claims (10)

A dilution step for diluting a high pH organic waste liquid containing high concentration sodium chloride;
An acid fermentation process in which the organic waste liquid in which the sodium chloride concentration is diluted in the dilution process is acid-fermented;
A neutralization step of neutralizing the organic liquid waste acid fermented in the acid fermentation step to a pH of 5.5 to 8.5;
A methane fermentation step for methane fermentation of the organic waste liquid having a pH of 5.5 to 8.5 in the neutralization step;
Organic waste liquid treatment method to perform in order.   The organic waste liquid processing method of Claim 1 which performs the aerobic process process which decomposes | disassembles the organic waste liquid methane-fermented in the said methane fermentation process further by an aerobic microbe.   The organic waste liquid treatment method according to claim 2, wherein the neutralization process is performed by mixing the organic waste liquid obtained in the aerobic treatment process with the organic waste liquid subjected to the acid fermentation in the acid fermentation process.   The organic waste liquid processing method as described in any one of Claims 1-3 which mixes the organic waste liquid before acid fermentation with the organic waste liquid acid-fermented at the said acid fermentation process, and performs the said neutralization process.   The organic waste liquid treatment method according to any one of claims 1 to 4, wherein in the dilution step, the organic waste liquid is diluted so that a sodium chloride concentration is 2.0% or less. A dilution section for diluting high-concentration sodium chloride-containing, high-pH organic waste liquid,
An acid fermentation part for acid fermentation of the organic waste liquid in which the sodium chloride concentration is diluted in the dilution part,
A neutralization treatment unit for neutralizing the organic waste liquid acid-fermented in the acid fermentation unit to a pH of 5.5 to 8.5;
A methane fermentation section for methane fermentation of an organic waste liquid having a pH of 5.5 to 8.5 in the neutralization section;
An organic waste liquid treatment apparatus provided with a gas consuming unit that consumes methane gas obtained in the methane fermentation unit as fuel.   The organic waste liquid processing apparatus of Claim 6 provided with the waste_water | drain supply part which supplies low concentration sodium chloride containing waste_water | drain to the said dilution part.   The organic waste liquid treatment apparatus according to claim 7, wherein the low-concentration sodium chloride-containing wastewater is a mixed wastewater of cooling water or washing wastewater in a soap production salting-out step.   The said organic waste liquid is a waste liquid of the salting-out process in soap manufacture, The organic waste liquid processing apparatus as described in any one of Claims 6-8.   The organic effluent treatment apparatus according to any one of claims 6 to 9, wherein the methane fermentation section includes a UASB reaction tank that performs methane fermentation by the UASB method.

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