JPH0236320B2 - HAISUISHORIHOHO - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a wastewater treatment method, and more particularly, to a food factory using animal and vegetable oils as raw materials,
Or it relates to a method for removing or reducing glycerin, BOD, and COD from wastewater with a particularly high glycerin content discharged from food processing plants or fat processing plants that handle or discharge fats and oils, or processing plants for oil-related chemical products, etc. . Therefore, the present invention plays an extremely important role not only in the technical field of wastewater treatment, but also in the technical field of various foods that handle large quantities of animal and vegetable oils, and the technical field of soap and other oil-related chemical products. . (Prior Art) When fatty acids are obtained from animal and vegetable oils, large amounts of glycerin are mixed into wastewater, and if the wastewater is discharged as is, the rivers become highly nutrient-rich and polluted. Furthermore, even if such wastewater is treated by the activated sludge method, the activated sludge cannot fully demonstrate its activity due to the large amount of glycerin, and in the end, even the activated sludge method cannot fully demonstrate its activity. Cannot be processed. Even if microbial treatment is attempted, most microorganisms do not assimilate glycerin, and the growth of the microorganisms themselves is inhibited by the high concentration of glycerin. Thus, among microorganisms, it was previously unknown that yeast, especially yeast of the genus Satucharomyces, could assimilate glycerin, and furthermore, there is no suggestion that it could be used industrially for the treatment of glycerin-containing wastewater. The current situation is that it is not even known. (Disclosure of the invention) In view of the current state of technology, the present inventors have
As a result of studying various aspects of chemistry, biology, and physics regarding industrial treatment methods for high-glycerin-containing wastewater, although no success had been achieved in the past, in the end,
We found that microbial treatment was the most likely option. Therefore, the present inventors prepared a solution containing glycerin and
We conducted an intensive search for bacteria that can decompose and assimilate glycerin and BOD even under adverse conditions in wastewater containing high concentrations of BOD.
They succeeded in isolating a mutant strain of Saccharomyces cerevisiae var.ellipsoideus. As a result of screening based on this new knowledge, they discovered that other yeasts of the genus Satucharomyces also had excellent properties, and continued their research.
The present invention has finally been completed. The strains isolated here are essentially
It has the mycological properties of Saccharomyces cerevisiae var.
This is a new mutant strain that can eliminate or reduce BOD. This mutant strain is Saccharomyces cerevisiae var.
It was named ellipsoideus YS-1 and was sent to the Institute of Fine Technology.
Deposited as FERMP No. 4498. This mutant strain is essentially Saccharomyces cerevisiae var.ellipsoideus except for its ability to assimilate glycerin.
It has the mycological properties of
Yeasts.a taxonomic study 2nd edition (J.
The outline is as follows: Proliferation is by multipolar budding; cells are generally oval;
Formed pseudohyphae and formed 4 ascospores. It does not form a film and exhibits properties of nitrate assimilation and arbutin decomposition. The sugar assimilation (fermentation) properties are as follows. galucose+(+) lactose-(-) galactose+(+) raffinose+(++) sucrose+(+) arabinose+ maltose+(+) Next, fatty acid production wastewater (BOD: 24000ppm,
COD: 18000ppm, glycerin: 8900ppm, PH
5.0), this strain, and as a control,
Hansenula anomala Y-1, Kluyveromyces
KL-5 and Hansenula anomala AM-6 were inoculated at ¹⁰⁷ bacteria/ml and cultured at 30°C for 40 hours. The results are shown in the following table.

[Table] As is clear from the above results, it can be seen that this bacterium extremely effectively assimilated glycerin and lowered BOD. The present invention relates to the above-mentioned Saccharomyces cerevisiaeval ellipsoideus YS-1.
In addition to FERM-P No. 4498 (hereinafter sometimes referred to as "YS-1" bacteria), various bacteria belonging to Saccharomyces are used as appropriate, such as the following: Saccharomyces bayanus IFO
2027; S. bisporus ATCC 8381; S. chevalieri
NRRL Y-1547; S.rosei IFO 1180; S.rouxii
IFO 0846; S. uvarum NRRL Y-1005. The wastewater treatment in the present invention is carried out by inoculating the glycerin-containing wastewater itself, its diluted solution, or pre-treated water such as filtration, centrifugation, chemical treatment, etc. with Satucharomyces bacteria. Bacteria of the genus Satucharomyces may be used as bacteria obtained by pure culture, cultures obtained by mass culturing from seed bacteria without separating the bacteria, or bacteria grown in large quantities through actual wastewater treatment. The body may be returned and used. The amount of inoculation is preferably about 10 ⁶ to 10 ⁷ cells/ml, but the amount of inoculation is changed depending on the length of culture time. Culture conditions are 20-35
℃ is preferred, but wastewater treatment is possible if cultured for a long time at temperatures below 20℃. For culture, use stirring aeration, etc.
It is done aerobically. In the treatment of the present invention, a phosphorus source or a nitrogen source such as urea may be added as a yeast nutrient, if necessary. Although the wastewater treated according to the present invention can be discharged into a river as it is, it is also possible to treat it again using conventional sewage and sewage treatment. For example, glycerin-containing wastewater treated by the microbial cells of the present invention is sent to an activated sludge tank as it is or after being mixed with wastewater with reduced COD, etc., to more effectively remove COD. At this time, bacterial cells present in large quantities in the wastewater may be separated, but bacteria of the genus Satucharomyces are safe and harmless as they are widely used in the food industry as brewer's yeast, baker's yeast, etc. It is not necessary to separate and remove these microbial cells, and there is no problem in directly feeding them into the activated sludge tank as they are, and this is also more convenient from the standpoint of wastewater treatment. Furthermore, the yeast sent into the activated sludge treatment tank becomes a nutrient source for the activated sludge, increasing the activity of the sludge, and there is no peeling of sludge from the structure, which is extremely convenient for activated sludge treatment, which is advantageous. Although commonly used activated sludge treatment tanks such as lagoons and trickling filters can be widely used, the most convenient type of activated sludge treatment is one in which activated sludge is attached to a structure such as a honeycomb. It's a tank. Activated sludge treatment is carried out by circulating the activated sludge zone adhering to a fixed bed while aerating it through an aeration tube while still containing bacterial cells. Through this treatment, the COD of treated wastewater (including yeast cells) is reduced to about 20 to 50 ppm (after natural sedimentation of microorganisms). In this case, it is a matter of course that the microorganisms may be forcibly separated by coagulation and sedimentation using a flocculant, centrifugation using a centrifuge, etc. without waiting for natural sedimentation. Conventional methods can be used as appropriate for the treatment of coagulation and precipitate using a flocculant; for example, a coagulation and precipitation method using a combination of ferric chloride, polyaluminum chloride and polyacrylamide is effective. In this coagulation-sedimentation method, ferric chloride is added to treated wastewater containing bacterial cells while stirring. This addition reduces the pH, so the pH is adjusted to 6.5 to 7.5, preferably 7.0, using an alkaline solution such as caustic soda. This pH is a necessary condition for the generation of giant flocs. The amount of COD remaining decreases as iron ions increase, but adding a large amount is not economical and also causes iron ions to remain in the treatment solution, which is undesirable.
Preferably, it is necessary to add ferric ions at a concentration of 100 to 300 ppm. 10% polyaluminum chloride under the above pH adjustment
Add about 200 to 300 ml of % solution per 1 m ³ of waste water, and add about 10 ppm of polyacrylamide to make the flocs larger. The constant sedimentation speed of the produced flocs is approximately 5 to 6 m/hour, making it possible to separate and remove the flocs by coagulation and sedimentation. The resulting precipitate is easily separated by filtration. The final COD and BOD of wastewater will both be 5 to 30 ppm, allowing it to be discharged as is. Bacteria of the genus Satucharomyces may be used alone, but various types of bacteria may be used in combination within the same species or between different species, if necessary. When used in combination, it is convenient to prepare a mixed culture of each bacteria in advance. (Effects of the Invention) As detailed above, the present invention can treat glycerin-containing wastewater, which has been difficult to treat with YS
-1 bacteria and other glycerol-assimilating bacteria of the genus Satucharomyces have made it possible for the first time to treat industrially and in large quantities. This is a significant contribution. Furthermore, the wastewater treated in this way does not destroy the activated sludge that has been widely used in the past, so it can be directly treated by being led to a commonly used activated sludge tank. COD and BOD of glycerin-containing wastewater from approximately 5 to
can be easily reduced to around 30ppm,
In other words, it is possible to achieve the remarkable effect of being able to reduce the noise to an almost complete level. Therefore, the present invention has significant benefits in the treatment of wastewater, particularly wastewater from the manufacture of fatty acid-related products. In addition, the majority of Saccharomyces bacteria are edible, and there is no fear of toxicity, so the proliferating bacteria can be used as animal and poultry feed, fish feed, etc. Beneficial. Next, test examples and examples of the present invention will be shown. Test example 1 Glycerin-containing wastewater (COD18000ppm.PH5.0)
50ml was placed in a 500ml Sakaguchi flask. On the other hand, Saccharomyces cerevisiae var.
ellipsoideus YS-1 FERM-P No.4498
One platinum loopful was inoculated into 50 ml of MY medium, cultured with shaking at 30°C for 20 hours, and after the cultivation was completed, the bacterial cells were centrifuged and further washed with physiological saline to prepare bacterial cells for inoculation. These bacterial cells were inoculated into the flask at a concentration of ¹⁰⁷ cells/ml, and shaken at 30°C for 40 hours. COD (ppm), glycerin, before and after treatment
Measure total N (ppm) and total P (ppm) and remove rate (%)
was calculated. The results are shown in the following table.

[Table] Test Example 2 The same treatment conditions as Test Example 1 were carried out, and the following bacterial strains were inoculated at a number of ¹⁰⁷ bacteria/ml and shaken at 30°C for 40 hours to determine the PH and BOD removal rate (%) after treatment. ) The number of bacteria was measured. 1 Saccharomyces cerevisiae var.
ellipsoideus YS-1, FERM-P No.4498 2 Hansenula anomala Y-1 FERM-P
No.3594 3 Kluyveromyces sp.KL-5 FERM-P
No.3970 4 Harsenula anomala AM-6 The results are shown in the following table.

[Table] As is clear from the above table, this bacterium exhibits superior BOD removal ability compared to other bacteria. Test example 3 MY medium Glucose 10g Yeast extract 3g Malt extract 3g Peptone 5g Water 1000ml Use glycerin (1%) instead of glucose in the above MY medium, adjust this medium to pH 4.5, and put 100ml into a 500ml Sakaguchi flask. ,
Saccharomyces cerevisiae var.ellipsoideus YS
-1 FERM-P No.4498 was inoculated at ¹⁰⁷ seeds/ml,
After shaking at 30℃ for 40 hours, the PH, COD,
Glycerin and bacterial counts were measured. The results are shown in the table below.

[Table] Example 1 1.5% of glycerin-containing wastewater was put into a treatment tank, and Saccharomyces cerevisiae var.
ellipsoideus YS-1, FERM-P No.4498 10 ⁷
After inoculating and culturing at 30° C. with aeration and stirring, wastewater was continuously fed so that the residence time was 48 hours. Removes an average of 75% of BOD in 20 days of continuous treatment,
COD removes an average of 71%, glycerin from 90%
The removal rate was 95%, and treated water was stably obtained. Subsequently, the wastewater was aerated in an activated sludge treatment tank for a residence time of 48 to 72 hours, and the treated wastewater was separated from the sludge by natural sedimentation. The supernatant liquid was discharged, but the COD and BOD of the treated water were 10 to 25 ppm after 20 days of continuous treatment. Example 2 In Example 1, glycerin-containing wastewater was treated in the same manner as in Example 1 using Satucharomyces ubarum NRRL Y-1005 instead of the YS-1 bacteria to obtain treated water that could be discharged into a river.

Claims (1)

[Claims] 1. A method for treating glycerin-containing wastewater, which comprises adding glycerol-assimilating yeast belonging to the genus Satucharomyces to glycerin-containing wastewater to assimilate glycerin.