JP2017056452A - Processing method and processing equipment for high concentration organic solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for treating a highly dense organic solution biologically conveniently at a low cost without causing a fermentation obstruction, when the highly dense organic solution is subjected to a biological treatment.SOLUTION: A processing equipment comprises: a dilution part 3 for diluting a high-concentration organic solution 1a with dilution water thereby to acquire a diluted solution 3a; and biological treatment parts (4, 5, 6 and 8) for biologically treating the diluted solution 3a. The dilution part 3 is caused to contact the high-concentration organic solution 1a and a low-concentration solution 2a through a permeable membrane 30, and seepage water is caused to permeate from the low-concentration solution side to the high-concentration solution side, so that the diluted solution 3a diluted from the high-concentration organic solution 1a is obtained by the correctly permeable membrane method, in which the seepage water is the dilution water.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-concentration organic solution processing method for performing a biological treatment step of performing a biological treatment step of diluting a high-concentration organic solution with dilution water to obtain a diluted solution, and a high-concentration organic solution The present invention relates to a high-concentration organic solution processing apparatus including a dilution unit that dilutes a diluted solution with dilution water to obtain a diluted solution, and a biological processing unit that biologically processes the diluted solution.

  For example, high-concentration organic solutions in the soap manufacturing industry contain organic substances such as glycerin and fatty acids. Conventionally, these high-concentration organic solutions have been discarded after recovering and regenerating valuable organic substances. However, in recent years when glycerin as a by-product of biodiesel fuel production is distributed in large quantities, the recovery of glycerin from high-concentration organic solutions has become unsuitable for cost. In recent years, such high-concentration organic solutions have been incinerated. Disposal is becoming mainstream.

  However, when such a treatment is performed, there are problems such as high energy waste and high environmental load. Therefore, effective use of organic substances in high-concentration organic solutions has been studied. As a utilization form of the organic matter in the high-concentration organic solution, except for recovery and regeneration, it is conceivable to recover energy as methane gas by utilizing methane fermentation by microorganisms. However, high-concentration sodium chloride-containing, high-pH organic solution is not preferable as an environment where microorganisms that perform methane fermentation are active, and there is a situation that it cannot be applied to the high-concentration organic solution in the soap manufacturing industry. .

  In contrast, the present applicants have previously developed a technique for biological treatment by appropriately diluting such a high-concentration organic solution and adjusting the pH (see Patent Document 1). With this technology, it became possible to biologically treat high-concentration organic solutions at low cost by effectively using easily available wastewater as a low-concentration solution with the addition of relatively simple processes.

  In the following, description will be given mainly using soap manufacturing waste liquid as an example, but as shown in Patent Document 1, various industrial waste liquids such as biodiesel manufacturing industry have similar problems, and this kind of waste liquid The production of methane from the organic matter is being studied. Therefore, in the present application, these waste liquids are collectively referred to as high-concentration organic solutions.

JP2012-152675A

  However, according to the present inventors, it has become clear that when an easily available low-concentration solution is used as it is for diluting a high-concentration organic solution, it may adversely affect biological treatment. For example, equipment used as a low-concentration solution, such as surfactants used for cleaning, or heavy metal ions generated from metal rust attached as equipment stains are dissolved it is conceivable that. It is considered that such dissolved components may contain substances that inhibit the growth of various microorganisms used for methane fermentation and acid fermentation and cause fermentation inhibition.

  Thus, it is conceivable to remove these dissolved components from the low-concentration solution and use them for dilution. However, the dissolved components are often not removed by coagulation sedimentation treatment or the like. It is also conceivable to obtain clean dilution water by treating the low concentration solution by the reverse osmosis membrane method. However, in order to perform the treatment by the reverse osmosis membrane method, it is necessary to apply a high pressure against the osmotic pressure of the low-concentration solution, which adds an energy-intensive process, and a simple and low-cost high-concentration organic solution. The original purpose of biological treatment of the plant cannot be achieved.

  Therefore, in view of the above circumstances, the present invention provides a technique for processing so that fermentation inhibition is unlikely to occur even when a high-concentration organic solution is diluted in a simple and low-cost biological treatment. Objective.

[Configuration 1]
In order to achieve the above object, the characteristic configuration of the processing method of the high concentration organic solution of the present invention is:
Dilute a highly concentrated organic solution with dilution water to obtain a diluted solution,
A treatment method of a high concentration organic solution for sequentially performing a biological treatment step of biologically treating the diluted solution,
In the dilution step, the high-concentration organic solution and the low-concentration solution are brought into contact with each other through a permeation membrane, and permeation water is permeated from the low-concentration solution side to the high-concentration organic solution side, thereby diluting the permeation water. The point is to obtain the diluted solution obtained by diluting the high-concentration organic solution by a forward osmosis membrane method using water.

[Operation effect 1]
Even if the dissolved component contained in the high-concentration organic solution has a high concentration that may inhibit the growth of microorganisms, diluting the high-concentration organic solution reduces the concentration of the dissolved component to a concentration at which microorganisms can easily grow. be able to. Therefore, it is considered that a biological treatment process for biologically treating the diluted solution after the dilution process can be suitably performed.

  Here, it is considered preferable to perform the dilution step with a low-concentration solution because the cost required for the dilution water can be reduced and the treatment of the low-concentration solution can be performed simultaneously as compared with the case where tap water is used as the dilution water. It is done. In this case, as described above, the dissolved component contained in the low-concentration solution contains substances that inhibit the growth of various microorganisms used for methane fermentation and acid fermentation and cause fermentation inhibition. There is. However, according to the present inventors, the high-concentration organic solution and the low-concentration solution are brought into contact with each other through an osmosis membrane, and so-called forward osmosis is caused to permeate permeated water from the low-concentration solution side to the high-concentration organic solution side. By using the membrane method, it became clear that permeated water from which substances causing fermentation inhibition were removed from a low-concentration solution was obtained.

  Therefore, the dilution process which uses the obtained osmotic water as dilution water can be performed, and fermentation inhibition can be hardly caused in the biological treatment process. Further, a normal osmosis membrane in which a high-concentration organic solution and a low-concentration solution are brought into contact with each other through an osmotic membrane, and the osmotic water is permeated from the low-concentration solution side to the high-concentration organic solution side. Since it is a method, compared with removing the substance which causes fermentation inhibition by a reverse osmosis membrane method, it is not necessary to give especially big energy, and osmotic water can be obtained simply and at low cost.

  Therefore, it is possible to dilute the high-concentration organic solution using the low-concentration solution in a simple and low-cost manner so that it can be used for the biological treatment process.

[Configuration 2]
The high-concentration organic solution may contain soap production waste liquid as a main component.

[Operation effect 2]
In addition, as the waste liquid for soap production, the waste liquid discharged from the salting-out process in the soap production facility contains a large amount of glycerin and sodium chloride, so it has a high concentration (high COD and high salt concentration) and high pH. It has been known. Therefore, it is suitable as a high-concentration organic solution to be processed by the processing method of the high-concentration organic solution, and it is possible to produce a valuable material while effectively using the waste liquid of the soap production facility with extremely high efficiency.

[Configuration 3]
The low-concentration solution may be mainly composed of cooling water or washing water in a facility that generates the high-concentration organic solution.

[Operation effect 3]
In addition, the cooling water and washing wastewater in the soap production facility are low in concentration (low COD and low salt concentration) and low pH in the cooling water distributed to the heat exchanger in various processes in the soap production facility and in the washing wastewater such as piping. It is known that Therefore, it is suitable as a low-concentration solution to be processed by a processing method for a high-concentration organic solution, and it is possible to produce a valuable material while effectively using the waste water of the soap manufacturing facility with extremely high efficiency.

  In particular, when the high-concentration organic solution is mainly composed of soap production waste liquid, and the low-concentration solution is mainly composed of cooling water or washing water in a facility that generates the high-concentration organic solution. It is preferable because two types of waste liquid and waste water generated from the same facility can be effectively used in combination and processed simultaneously.

[Configuration 4]
In order to achieve the above object, the high-concentration organic solution processing apparatus according to the present invention has the following characteristic configuration:
A treatment apparatus for a high concentration organic solution, comprising a dilution section for diluting a high concentration organic solution with dilution water to obtain a diluted solution, and a biological treatment section for biologically treating the diluted solution,
The diluting unit makes the high-concentration organic solution and the low-concentration solution contact each other through a permeation membrane, and permeates the high-concentration organic solution side from the low-concentration solution side to infiltrate the permeated water. This is a configuration in which the diluted solution obtained by diluting the high-concentration organic solution is obtained by a forward osmosis membrane method using water.

[Operation effect 4]
Even if the dissolved component contained in the high-concentration organic solution has a high concentration that may inhibit the growth of microorganisms, diluting the high-concentration organic solution reduces the concentration of the dissolved component to a concentration at which microorganisms can easily grow. be able to. Therefore, it is considered that a biological treatment process for biologically treating the diluted solution obtained in the dilution section can be suitably performed.

  Here, if the dilution water is a low-concentration solution, it is considered preferable because the cost required for the dilution water can be reduced and the treatment of the low-concentration solution can be performed simultaneously as compared with the case where tap water is used as the dilution water. . In this case, as described above, the dissolved component contained in the low-concentration solution contains substances that inhibit the growth of various microorganisms used for methane fermentation and acid fermentation and cause fermentation inhibition. There is. However, according to the present inventors, the high-concentration organic solution and the low-concentration solution are brought into contact with each other through an osmosis membrane, and so-called forward osmosis is caused to permeate permeated water from the low-concentration solution side to the high-concentration organic solution side. By using the membrane method, it became clear that permeated water from which substances causing fermentation inhibition were removed from a low-concentration solution was obtained.

  Therefore, the obtained osmotic water can be used as dilution water, and fermentation inhibition can be hardly caused in biological treatment. Further, the high concentration organic solution and the low concentration solution are brought into contact with each other through the osmosis membrane, and the osmotic water is permeated from the low concentration solution side to the high concentration organic solution side, and the obtained osmotic water is used as dilution water. Therefore, it is not necessary to apply particularly large energy compared to removing substances that cause fermentation inhibition by the reverse osmosis membrane method, and osmotic water can be obtained simply and at low cost.

  Therefore, it has become possible to dilute the high-concentration organic solution so that it can be biologically treated using the low-concentration solution easily and at low cost.

  As described above, when treatment with an osmotic membrane is performed, osmotic water is obtained by removing substances that cause fermentation inhibition from low-concentration solutions. However, substances that cause fermentation inhibition include surfactants. Also, heavy metal ions and organic compounds are assumed. Although it is not certain which substance causes actual fermentation inhibition in detail, the present inventors have found that fermentation inhibition can be suppressed by removing these substance groups. Thus, it is clear that fermentation inhibition can be suppressed by using a permeable membrane capable of membrane separation of these substance groups.

  The above surfactants, heavy metal ions, and organic compounds are generally used as forward osmosis membranes (FO membranes), reverse osmosis membranes (RO membranes), nanofilters (NF membranes), ultrafiltration membranes (UF membranes), and microfiltration membranes. It is considered that the membrane can be separated by (MF membrane), and these membranes are useful as osmotic membranes used in the forward osmosis membrane method.

In the present invention,
Reverse osmosis membrane (RO membrane) refers to a membrane that separates a substance with a molecular weight (fractionated molecular weight) of about 60 Da to less than 350 Da.
The forward osmosis membrane (FO membrane) refers to a membrane that separates a substance having a molecular weight of about 60 Da or more and less than 1000 Da.
A nanofilter (NF membrane) refers to a membrane that separates a substance having a molecular weight of about 350 Da to less than 1000 Da.
An ultrafiltration membrane (UF membrane) refers to a membrane that separates a substance having a molecular weight of about 1000 Da or more and less than 300000 Da.
A microfiltration membrane (MF membrane) refers to a membrane that separates a substance having a molecular weight of 300,000 Da or higher.

[Configuration 5]
The biological treatment unit is an acid fermentation unit for acid fermentation of the diluted solution;
A neutralization treatment section for neutralizing the acid fermentation solution acid-fermented in the acid fermentation section to a pH of 5.5 to 8.5;
And a methane fermentation section in which the neutralized solution having a pH of 5.5 to 8.5 in the neutralization processing section is subjected to methane fermentation to obtain a methane fermentation solution.

[Operation effect 5]
When the diluted solution diluted in the dilution unit by the acid fermentation unit is acid-fermented as the biological treatment unit, the acid-producing bacteria assimilate the organic matter in the diluted solution, acid-ferment the diluted solution, and the diluted solution becomes more fluid And the contained organic matter 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 a diluted solution.

  Moreover, when the acid fermentation solution is neutralized to pH 5.5 to 8.5 by the neutralization treatment unit, the neutralized neutralized solution is adjusted to an environment suitable for the growth of the methanogen. If the neutralization treatment is performed at a pH of 5.5 to 8.5, it is difficult for microorganisms to interfere with the activity of the microorganism, and an appropriate microorganism growth environment is maintained even if the pH of the neutralization solution further varies due to the action of microorganisms. This is preferable. Here, since the neutralization solution has been subjected to an acid fermentation process, the organic matter has been moderately reduced in molecular weight and digested to conditions under which methane fermentation can be performed efficiently. It can be carried out.

  Especially for acid fermentation part, after dilution, acid fermentation is not performed, and if neutralized neutralized solution is used for methane fermentation part, acid fermentation that lowers pH and organic acid is decomposed to raise pH Methane fermentation occurs simultaneously. Therefore, the pH tends to become unstable, and it may be difficult to cause methane fermentation stably. Therefore, it became possible to stabilize pH by supplying the acid fermentation solution which passed through the acid fermentation part to a methane fermentation process, and to perform methane fermentation satisfactorily.

  Acid fermentation means that organic substances are decomposed 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 may be performed as a pretreatment of methane fermentation treatment for the purpose of solubilization of sludge, fermentation treatment of oil, and the like.

[Configuration 6]
The UASB reaction tank in which the methane fermentation unit performs methane fermentation by the UASB method may be used.

[Operation effect 6]
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 a UASB reaction tank that performs the UASB method is adopted as the methane fermentation part. The methane conversion ability with respect to the amount of organic matter in the high-concentration organic solution is high, and the reaction process speed is also high.

In addition, the UASB reaction tank by the UASB method (Upflow Anaerobic Sludge Blanket), which is known as a methane fermentation method, has a high sludge retention concentration and is capable of high load treatment. In recent years, food drainage has spread rapidly. 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) is formed and a high concentration of microorganisms is retained in the reaction tank to perform a high load treatment. In this method, compared with the aerobic activated sludge method, the organic matter load per reaction tank volume is as high as 10 kg-CODCr / m ³ / day or more. In addition, it has excellent features such as no energy for aeration; energy recovery as methane gas; small amount of excess sludge generation;

Therefore, it has become possible to perform biological treatment of a highly concentrated organic solution so that fermentation inhibition is unlikely to occur easily and at low cost.

Flow chart of processing equipment for high concentration organic solution

  Below, the processing method and processing apparatus of the high concentration organic solution concerning embodiment of this invention are demonstrated. Preferred embodiments are described below, but these embodiments are described in order to more specifically illustrate the present invention, and various modifications can be made without departing from the spirit of the present invention. The present invention is not limited to the following description.

[High-concentration organic solution processing equipment]
As shown in FIG.
A dilution unit 3 is provided to obtain a diluted solution 3a by diluting the high concentration organic solution 1a with dilution water,
Comprising biological treatment units 4, 5, 6, and 8 for biologically treating the diluted solution 3a;
The diluting part 3 is brought into contact with the high concentration organic solution 1a and the low concentration solution 2a through the osmosis membrane 30, and the other surface side in contact with the high concentration organic solution 1a from the one surface side 30A in contact with the low concentration solution 2a. A forward osmosis membrane device for extracting the osmotic water 30a is provided at 30B.

In the embodiment shown in FIG. 1, the biological treatment units 4, 5, 6, and 8 are acid-fermented by the acid fermentation unit 4 that performs acid fermentation of the diluted solution 3 a to obtain the acid fermentation solution 4 a, and the acid fermentation unit 4. The neutralization treatment part 5 which neutralizes the acid fermentation solution 4a to pH 5.5-8.5 and obtains the neutralization solution 5a, and neutralization which became pH 5.5-8.5 in the neutralization treatment part 5 The solution 5a is provided with a methane fermentation unit 6 that is subjected to methane fermentation to obtain a methane fermentation solution 6a. Further, the methane fermentation solution 6a treated in the methane fermentation unit 6 is aerobically biologically treated to perform an aerobic treatment solution 8a. The aerobic processing unit 8 is provided. In addition, the aerobic treatment part 8 should just be provided according to the water treatment condition (water quality of waste water) in the methane fermentation part 6, and depending on the treatment condition in the methane fermentation part 6, the aerobic treatment part 8 is not provided. It doesn't matter.
Moreover, the gas consumption part 7 which consumes the methane gas 6b obtained by the high concentration organic solution storage part 1 which stores the high concentration organic solution 1a, the low concentration solution storage part 2 which stores the low concentration solution 2a, and the methane fermentation part 6 as a fuel. Is provided.
With these configurations, the soap production waste liquid as the high-concentration organic solution 1a can be biologically treated by being diluted with the osmotic water 30a obtained from the cooling water or the washing waste water in the soap production facility as the low-concentration solution 2a.

[High concentration organic solution reservoir, low concentration solution reservoir]
In this embodiment, in the high concentration organic solution storage part 1, the soap manufacture waste liquid as the high concentration organic solution 1a is stored, for example. Moreover, in the low concentration solution storage part 2, the cooling water and washing waste_water | drain in a soap manufacturing facility are stored as the low concentration solution 2a. Here, as the high-concentration organic solution, the soap production waste liquid discharged from the salting-out process in the soap production facility contains a large amount of glycerin and sodium chloride, so that the concentration is high (high COD and high salt concentration) and high. It is known to be pH. In addition, as low-concentration solutions, cooling water and washing effluent in soap production facilities, cooling water circulated to heat exchangers in various processes in soap production facilities, and washing effluents such as pipes are compared to soap production wastewater. It is known that the concentration is sufficiently low (low COD and low salt concentration) and low pH. Examples of these properties are shown below.

Soap manufacturing wastewater:
CODCr; 40,000 to 120,000 mg / L
Cation concentration: 30000-60000 mg / L
pH; 9-13
Dissolved component: glycerin, sodium chloride dissolved component amount; glycerin 11%
Sodium chloride 12%

Cleaning drainage:
CODCr; 100-5000 mg / L
Cation concentration: 50 to 500 mg / L
pH; 6-8
Soluble component: Surfactant (cationic surfactant, anionic surfactant, amphoteric surfactant, nonionic surfactant), metal ion (iron ion, copper ion), benzenemethanol, methylbenzenemethanol, dimethylbenzene Ethanol, 2,2-dimethoxyethylbenzene, t-butylcyclohexanol, dimethylbenzenepropanol, triclosan, isopropylmethylphenol, phenoxyethanol, sodium benzoate, methyl paraoxybenzoate, ethylhexylglycerin, glyceryl caprate, 1,2-pentanediol, Ethanol, propyl paraoxybenzoate, isopropyl paraoxybenzoate, butanediol, 1,2-octanediol, salicylic acid, ethylenediaminetetraacetic acid (EDTA)
Dissolved component amount: CODCr concentration 120 mg / L

[Dilution part]
The dilution unit 3 includes a forward osmosis membrane device including a low concentration solution supply path 31, a concentrated solution discharge path 32, a high concentration organic solution supply path 33, and a diluted solution discharge path 34. That is, the low concentration solution supply path 31 receives the low concentration solution 2 a from the low concentration solution storage unit 2. In the concentrated solution discharge path 32, the received low concentration solution 2a is brought into contact with one surface side 30A of the osmotic membrane 30, and the permeated water 30a is taken out and then discharged as a concentrated solution 3c. In the high concentration organic solution supply path 33, the high concentration organic solution 1a from the high concentration organic solution storage unit 1 is received. In the diluted solution discharge path 34, the received high-concentration organic solution 1a is brought into contact with the other surface side 30B of the osmotic membrane 30, diluted with the osmotic water 30a, and then discharged as the diluted solution 3a. Thereby, the high concentration organic solution and the low concentration solution are brought into contact with each other through the osmotic membrane, and the permeated water is allowed to permeate from the low concentration solution side to the high concentration organic solution side.

  As the osmotic membrane 30, a forward osmotic membrane (FO) membrane is used in the present embodiment. More specifically, for example, a forward osmosis membrane (HTI TFC membrane) of about MWCO (fractionated molecular weight) 60 Da is used.

  With these configurations, the osmotic water 30a is such that the salt concentration on the other surface side 30B of the osmotic membrane 30 in the dilution section 3 is a predetermined value (for example, 2.0%) or less (more preferably, 1.5% or less). And a dilution step of discharging the diluted diluted solution 3a to the outside can be performed.

[Acid fermentation section]
The acid fermentation unit 4 includes an acid fermentation tank 40 that performs acid fermentation of the diluted solution 3a from the dilution unit 3, and the acid fermentation tank 40 includes a diluted solution supply unit 41 that receives the diluted solution 3a. A discharge part 42 for discharging the fermentation solution 4a is provided. In the acid fermentation section 4, sludge mainly containing facultative anaerobic bacteria (acid producing bacteria) is housed, and the diluted solution 3a introduced into the acid fermentation tank is subjected to acid fermentation to produce organic acids such as acetic acid. It is the structure which can perform the acid fermentation process to produce | generate.

[Neutralization section]
The neutralization process part 5 is equipped with the acid fermentation solution supply part 51 which supplies the acid fermentation solution 4a to the neutralization reaction tank 50 for the neutralization reaction process which neutralizes the acid fermentation solution 4a, and is alkali (for example, hydroxylation). The aqueous solution (sodium aqueous solution) 5b is provided with an alkali addition unit 52, and the neutralization step of receiving and mixing the acid fermentation solution 4a from the acid fermentation unit 4 and neutralizing it 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 addition unit 52. When the pH in the neutralization reaction tank 50 falls within a predetermined range (for example, pH 5.5 to 8.5), the neutralized neutralized solution 5a can be discharged out of the neutralization reaction tank 50 from the solution discharge unit 53. It is configured.

[Methane fermentation department]
As shown in FIG. 1, the methane fermentation unit 6 includes a UASB reaction tank 60, and the UASB reaction tank 60 has a sludge granule 60 a mainly composed of anaerobic bacteria (UASB bacteria) at the bottom. A sludge bed 61 is provided, and a high-concentration organic solution supply unit 62 that supplies the neutralized solution 5a discharged from the neutralization processing unit 5 as a methane fermentation solution 60b is provided. Thereby, while the upward flow of the introduced methane fermentation liquid 60b is formed, the circulation of the internal methane fermentation liquid 60b is promoted, and the methane fermentation process of methane fermentation of the organic substance by the flowing granule 60a is performed. At the upper part of the sludge bed 61, there is provided a separation plate 63 for preventing the granule 60a from flowing out and moving the processed supernatant and the generated methane gas 6b upward. The treated methane fermentation solution 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 is the composition which becomes. The overflow section 64 is provided with a circulating processing liquid circulation path 66 for circulating a part 6c of the methane fermentation solution 6a to the high-concentration organic solution supply section 62 so that the liquid line in the tower is maintained while maintaining a necessary residence time. The speed can be set to an appropriate 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.

[Gas consumption department]
The gas consumption unit 7 includes a fuel gas supply unit 70 that mixes the combustible gas 7a with the methane gas 6b recovered from the gas recovery unit 65 and supplies the fuel gas as fuel gas, and consumes the fuel gas as fuel to generate steam and power. It consists of a boiler, an engine, a turbine, etc. which generate 7b. 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.

[Aerobic treatment department]
The aerobic treatment part 8 can apply various known wastewater treatment tanks such as an activated sludge tank and a contact aeration tank, and further aerobically decomposes the methane fermentation solution 6a supplied from the methane fermentation part 6 to obtain a clean good An aerobic treatment process is performed that enables the gas treatment solution 8a to be discharged.

  Here, the acid fermentation process, the neutralization process, the methane fermentation process, and the aerobic treatment process performed in the biological treatment units 4, 5, 6, and 8 respectively correspond to the biological treatment process.

  In addition to the alkali addition unit 52, the neutralization unit 5 supplies a part 3 b of the diluted solution 3 a diluted in the dilution unit 3 directly from the bypass path 35 without passing through the acid fermentation unit 4. A supply unit 54 is provided so that a part or all of the alkali 5b to be supplied from the alkali addition unit 52 can be replaced with a part 3b of the diluted solution 3a so that the acid fermentation solution 4a subjected to acid fermentation can be neutralized. It is.

  Similarly, the neutralization processing unit 5 is provided with an aerobic treatment solution returning unit 55 that supplies and returns a part 8b of the aerobic processing solution 8a from the aerobic processing unit 8 through the return path 81. The acid fermentation solution 4a that has undergone acid fermentation by replacing part or all of the alkali 5b to be supplied from a part with the part 8b of the aerobic treatment solution 8a can also be configured to be neutralized.

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

[Example 1]
The high concentration organic solution 1a is supplied to the high concentration organic solution supply path 33 of the dilution unit 3, and the low concentration solution 2a is supplied to the low concentration solution supply path 31 to determine how much the high concentration organic solution 1a is diluted. Examined.

The dilution section 3 is provided with a forward osmosis membrane (HTI TFC membrane) having a membrane area of 42 cm ² as the osmosis membrane 30. Further, as the high-concentration organic solution 1a, a surfactant and a heavy metal ion are not included, a glycerin concentration of 11% (corresponding to CODCr 134000 mg / L) (% indicates mass% unless otherwise specified), a sodium chloride concentration of 12%, and a pH of 13 Soap manufacturing waste liquid was used. Moreover, the washing | cleaning waste_water | drain in the soap manufacturing facility of CODCr120mg / L was used as a low concentration solution 2a as a melt | dissolution component.

When supplying the high concentration organic solution 1a to the high concentration organic solution supply path 33 at 300 mL / min and supplying the low concentration solution 2a to the dilution section 3 at 300 mL / min, Without using external power under normal pressure, the permeated water 30a from one side 30A that contacts the low concentration solution 2a is taken out to the other side 30B that contacts the high concentration organic solution 1a, and the high concentration organic solution 1a is It was found to be diluted 6.7 times. At this time, the permeation amount is about 10-15 LMH (L / m ² / h), the back diffusion of salt (NaCl) is 0.1-0.4 mol / m ² / h, and the leakage of glycerin is less than 1%. there were.
[Example 2]
Moreover, in order to investigate the removal performance of the inhibitory component contained in the washing waste water, a test was performed in the same manner as in the method of Example 1, except that CODCr 0 mg / L, sodium chloride concentration 12%, pH 13 instead of the high concentration organic solution. In the same manner as in Example 1, washing waste water from a soap production facility was used as the low concentration solution 2a.
At this time, when the organic substance contained in the low concentration solution 2a and the obtained diluted solution 3a was compared by the solid phase adsorption GC / MS method, as shown in the following table, benzene methanol, methylbenzene methanol, It was revealed that dimethylbenzeneethanol, 2,2-dimethoxyethylbenzene, t-butylcyclohexanol, and dimethylbenzenepropanol were not detected at a concentration of less than 5 mg / L, or the concentration could be greatly reduced.

Example 3
When the acid fermentative bacteria collected from the acid fermenter 40 were cultured using the diluted solution 3a obtained in Example 1, the gene amount increased to 120% after 1-day culture, according to the 16S rRNA gene analysis. It was revealed.

  On the other hand, the high-concentration organic solution 1a of Example 1 was sampled from the acid fermenter 40 using the one diluted 6.7 times with the low-concentration solution 2a of Example 1 that does not go through the dilution section 3. When the acid-fermenting bacteria were cultured, it was revealed by 16S rRNA gene analysis that the gene amount was reduced to 10% after one-day culture.

  That is, it became clear that the organic compound contained in the low-concentration solution 2a contains a substance that becomes a fermentation inhibitor in acid fermentation.

Example 4
Similar to the method of Example 1, 200 ml of water adjusted to pH 13 with NaOH with a 12% NaCl solution simulating a high concentration solution, and ethylenediaminetetraacetic acid (EDTA simulating a low concentration solution containing an inhibitor) ) Was prepared by using 1000 ml of 100 mg / L water and diluting these solutions using a forward osmosis membrane (HTI TFC membrane) having a membrane area of 42 cm ² . Note that EDTA has an effect of chelating a micronutrient metal effective for microorganisms, and inhibits the activity of microorganisms in the long term. After the dilution treatment, about 800 ml of water moved from the low concentration solution side to the high concentration solution side. At this time, the total amount of EDTA contained in the high concentration solution was 7 mg, and the total amount of EDTA contained in the low concentration solution was 93 mg. . From the above, it was confirmed that in this process, it was possible to dilute the high concentration solution while preventing about 93% migration of EDTA, which is an inhibitor contained in the low concentration solution. Thereby, it is suggested that mixing of inhibitory substances including EDTA can be reduced and the influence on the biological treatment in the subsequent stage can be reduced.
Even if it uses the low concentration solution 2a in which the substance which inhibits the activity of microorganisms is used for the high concentration organic solution 1a using the dilution part 3 provided with the osmosis membrane 30 from Examples 1-4, it is simple and It became clear that it could be diluted biologically at low cost.

  In the present invention, it is expected that even a low concentration solution containing an inhibitor to microorganisms can be biologically treated without adversely affecting the high concentration organic solution. In the evaluation test, it was confirmed that the treatment using tap water as dilution water and the one using the present invention were processed without any difference for several months. Thus, for example, various high-concentration organic solutions such as waste liquid in the soap manufacturing industry and waste liquid in the biodiesel fuel manufacturing industry can be biologically treated and recovered as methane gas.

1a: High concentration organic solution 2a: Low concentration solution 3: Dilution part 3a: Dilution solution 4: Acid fermentation part (biological treatment part)
4a: Acid fermentation solution 5: Neutralization processing part (biological processing part)
5a: Neutralization solution 6: Methane fermentation part (biological treatment part)
6a: Methane fermentation solution 8: Aerobic treatment part (biological treatment part)
30: Osmosis membrane 30a: Osmosis water 60: Reaction tank

Claims (6)

Dilute a highly concentrated organic solution with dilution water to obtain a diluted solution,
A treatment method of a high concentration organic solution for sequentially performing a biological treatment step of biologically treating the diluted solution,
In the dilution step, the high-concentration organic solution and the low-concentration solution are brought into contact with each other through a permeation membrane, and permeation water is permeated from the low-concentration solution side to the high-concentration organic solution side, thereby diluting the permeation water. A method for treating a high concentration organic solution to obtain the diluted solution obtained by diluting the high concentration organic solution by a forward osmosis membrane method using water.   The processing method of the high concentration organic solution according to claim 1, wherein the high concentration organic solution has a soap production waste liquid as a main component.   The method for treating a high concentration organic solution according to claim 1 or 2, wherein the low concentration solution is mainly composed of cooling water or washing water in a facility that generates the high concentration organic solution. A treatment apparatus for a high concentration organic solution, comprising a dilution section for diluting a high concentration organic solution with dilution water to obtain a diluted solution, and a biological treatment section for biologically treating the diluted solution,
The diluting unit makes the high-concentration organic solution and the low-concentration solution contact each other through a permeation membrane, and permeates the high-concentration organic solution side from the low-concentration solution side to infiltrate the permeated water. An apparatus for processing a high concentration organic solution, wherein the diluted solution obtained by diluting the high concentration organic solution is obtained by a forward osmosis membrane method using water.   The biological treatment part is an acid fermentation part for acid fermentation of the diluted solution, a neutralization treatment part for neutralizing the acid fermentation solution acid-fermented in the acid fermentation part to pH 5.5 to 8.5, The processing apparatus of the high concentration organic solution of Claim 4 provided with the methane fermentation part which makes methane fermentation the neutralized solution used as pH 5.5-8.5 in the sum process part, and makes it a methane fermentation solution.   The processing apparatus of the high concentration organic solution of Claim 5 provided with the UASB reaction tank in which the said methane fermentation part performs methane fermentation by the UASB method.

Images