JP3167021B2 - Method for treating organic wastewater and chemicals used in the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for treating organic wastewater, and more particularly, to a method for treating organic wastewater with activated sludge, which suppresses the growth of bacteria constituting the activated sludge and reduces the surplus of the bacteria. The present invention relates to a method for treating organic wastewater that can significantly reduce the amount of sludge generated, and a chemical used for the method.

[0002]

2. Description of the Related Art Pollutants in water are decomposed and purified in nature such as rivers and lakes by physicochemical and biological actions such as precipitation, aggregation, oxidation and reduction. In particular, pollution containing organic matter is easily purified by microorganisms by biological action. As a method of purifying organic wastewater using this, there is an activated sludge method in which organic wastewater is treated with activated sludge containing aerobic microorganisms. Since this method has advantages such as high purification ability and relatively low treatment cost, various methods utilizing this have been proposed, and are widely and generally used in sewage treatment and industrial wastewater treatment. I have.

In the above-mentioned activated sludge method, the wastewater p
After performing pretreatments such as H adjustment and homogenization, the organic wastewater is led to an aeration tank (aeration tank) in which the activated sludge decomposes organic pollutants in the wastewater represented by BOD by activated sludge. Is purifying. At this time, 50 to 70% of the decomposed BOD is consumed as maintenance energy for the microorganism, but the remaining 30 to 50% is used for the growth of cells, so that the amount of activated sludge gradually increases. . For this reason, generally, as shown in FIG. 4, the wastewater treated in the aeration tank is guided to a settling tank, and the returned activated sludge is removed from the settled activated sludge by an amount required for the organic wastewater purification treatment. To the inside of the aeration tank, and other activated sludge is removed as surplus sludge. As described above, a large amount of excess sludge is generated in the purification treatment of organic wastewater using activated sludge, but this excess sludge contains a biodegradable substance and the like,
There are drawbacks such as high viscosity and difficulty in handling. When organic wastewater is purified by the activated sludge method, excess sludge treatment is always a problem.

[0004] On the other hand, the method of treating excess sludge, which is generally performed at present, includes a method of dehydrating excess sludge to separate water and incinerating solids or landfilling as industrial waste. Alternatively, the excess sludge is subjected to anaerobic digestion treatment, decomposed into methane gas, carbon dioxide, hydrogen, hydrogen sulfide, etc. to reduce the volume, and then the excess sludge that has not been decomposed and other solids are separated by dehydration, and the solids are separated Methods include incineration or disposal as industrial waste. Furthermore, in recent years, for the purpose of reducing excess sludge, a method has been known in which a part of the excess sludge is treated with ozone and then the ozone-treated sludge is introduced into an aeration tank to perform aerobic treatment. See JP-B-57-19719 and JP-A-7-88495.

However, the conventional method for treating excess sludge has various problems as described below. First, when the excess sludge is concentrated by a dehydrator without performing anaerobic digestion treatment and incinerated or disposed of as industrial waste, there is a problem that the processing cost is significantly increased due to a large amount of excess sludge. The disposal cost of sludge at present is as high as 20,000 to 30,000 yen / m ^3, and this disposal cost tends to increase further in the future. In addition, the impact on the global environment such as the problem of securing landfill disposal sites and the problem of increased energy consumption due to sludge incineration cannot be overlooked.

The above-described method for reducing excess sludge by anaerobic digestion has the advantage that energy is recovered as methane gas. However, the number of days required for digestion is as long as 20 to 40 days, and excess sludge is required. Since the decomposition rate is as low as about 60%, a large site area is required. Further, undecomposed excess sludge and other solids must be separated by a dehydrator and incinerated or disposed of as industrial waste. There is a problem that the processing cost increases due to inefficiency. Further, as described above, there is a problem of influence on the global environment.

The method of treating a part of the excess sludge with ozone can considerably reduce the volume of the excess sludge, but requires a special ozone generator. Therefore, it is not suitable for small-scale facilities, and there is a practical problem that equipment costs are high, operating costs are increased, processing costs are increased, and economic efficiency is poor.

[0008]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method for treating organic wastewater using activated sludge without generating excess sludge without deteriorating the quality of the treated water discharged in the final stage. It is an object of the present invention to provide a simple and economical method for treating organic wastewater and a chemical used therefor, in which the amount can be significantly reduced and the cost for treating excess sludge can be reduced.

[0009]

The above objects are achieved by the present invention described below. That is, according to the present invention, when the organic wastewater is purified using activated sludge, the acid or waste acid is removed at a treatment temperature of 40 to 50 ° C. in any of the treatment steps.
By adding so as to be H2.5 to 3.5,
A method for treating organic wastewater characterized by disinfecting or lysing some of the bacteria constituting the activated sludge and suppressing the growth of the activated sludge during the treatment process, and utilizing the activated sludge from the organic wastewater In the case of performing purification treatment, an alkaline agent is added so as to have a pH of 10 to 11 at room temperature or a treatment temperature of 40 to 50 ° C. in any one of the treatment steps to remove bacteria constituting the activated sludge. A method for treating organic wastewater characterized by suppressing the growth of activated sludge during the treatment process by disinfecting or dissolving a part of the organic wastewater, and furthermore, when purifying the organic wastewater using activated sludge, Temperature during the process
Alternatively , waste nitric acid and aqueous hydrogen peroxide are added at a treatment temperature of 40 to 50 ° C. to sterilize or lyse some of the bacteria constituting the activated sludge, thereby suppressing the growth of the activated sludge during the treatment process. A method for treating organic wastewater, characterized by the fact that:
Drugs used for these.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described in more detail. The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, as shown in FIG. 4, in a conventional method of treating organic wastewater using activated sludge, an aeration tank was used. A part of the activated sludge taken out from the inside or the settling tank is controlled by controlling the pH or temperature, or an alkali agent, an acid or a waste acid, or a compound having a bactericidal action or a lytic action on the activated sludge. By adding, or by combining two or more of the above requirements (hereinafter, also simply referred to as various sterilization or lysis treatment means), sterilization or lysis treatment is performed, and the treated product is returned to the aeration tank again to be activated sludge treatment. If you do
The present invention has been found that the amount of excess sludge generated can be extremely small without impairing the quality of the final treated water as compared with the conventional case.

That is, when activated sludge is treated by the various sterilization or lysis treatment means mentioned above, any of the above means causes damage to the cell wall (membrane) of the bacteria constituting the activated sludge and destroys them. It has excellent functions of lysing bacteria and hydrolyzing the cytoplasm that constitutes the bacteria to cause dysfunction, so that the cell walls of the bacteria are destroyed and polysaccharides and proteins in the cell walls are dissolved. (In this specification, this state is referred to as lysis.) Since the bacteria themselves become organic pollutants in wastewater represented by BOD and serve as good food for the bacteria, excessive growth of activated sludge is suppressed, A reduction in the amount of excess sludge is achieved. Further, the present invention is not limited to the method of treating a part of the activated sludge taken out from the aeration tank or the sedimentation tank.In the case of purifying the organic wastewater using the activated sludge, in any of the treatment steps, If a part of the bacteria constituting the activated sludge is sterilized or lysed by various sterilization or lysis treatment means, the amount of activated sludge during the treatment process can be maintained at a necessary and sufficient amount for the purification treatment, It was found that the amount of excess sludge generated could be extremely small without impairing the quality of the final treated water.

The present inventors control pH or temperature, or add a compound having a bactericidal or bacteriolytic action to an alkaline agent, an acid or waste acid, and activated sludge, or use various combinations of these as appropriate. By performing the sterilization or lysis treatment of the bacteria constituting the activated sludge by the means, the amount of generation of the excess sludge can be reduced because the excess growth of the activated sludge is suppressed as described below. I believe. In the biological treatment of wastewater with activated sludge, organic matter in the water to be treated is oxidatively decomposed by bacteria constituting the activated sludge, and the bacteria themselves grow with the organic matter as a nutrient source. Therefore, it can be said that the organic matter in the wastewater has been converted into bacteria by looking only at the phenomenon caused by the bacterial treatment. According to the study of the present inventors, the conversion rate is about 40 to 50 in terms of the conversion rate of organic matter to bacteria.
%, And 100 parts by weight of organic matter is converted into about 40 to 50 parts by weight of bacteria. On the other hand, when this phenomenon is viewed from the bacteria side, it means that the amount of bacteria has increased by 40 to 50 parts by weight. Then, these bacteria cannibalize each other, or are preyed by protozoa, and settle as activated sludge having good cohesiveness and sedimentation.

[0013] Therefore, the present inventors can promote the so-called cannibalism of bacteria, reduce the amount of bacteria (activated sludge) that gradually grows with organic matter as feed, and reduce the generation of excess sludge. We thought that the problem could be solved, and conducted various studies on the conditions that could promote bacterial cannibalism. As a result, by controlling the pH or temperature of the activated sludge treatment tank,
Alternatively, by adding an alkaline agent, an acid or waste acid, or a compound having a bactericidal action or a bacteriolytic action to activated sludge, and further by treating under a condition combining these means, Since the cell wall of the bacteria constituting the sludge is easily destroyed and sterilized or lysed, and the polysaccharides and proteins in the cell wall can be dissolved out (see FIG. 1), the bacteria themselves are represented by BOD. It was found that the organic pollutants can be efficiently changed to organic pollutants and are effective. In other words, polysaccharides and proteins that come out when bacteria are sterilized or lysed are suitable foods for bacteria and protozoa, and a part of the activated sludge is treated by the various sterilization or lysis treatment means described above. Then, the growth of bacteria can be remarkably suppressed (see FIG. 1).

In the method for treating organic wastewater of the present invention,
When purifying organic wastewater using activated sludge,
In any of the treatment steps, any condition may be used as long as a part of the bacteria constituting the activated sludge is treated by various sterilization or lysis treatment means described below. In the present invention, as a means for disinfecting or lysing a part of bacteria, an acid or waste acid having a pH of 2.5 at a treatment temperature of 40 to 50 ° C is placed in a treatment tank containing activated sludge to be treated.
To 3.5 or at room temperature or
At a processing temperature of 40 to 50 ° C. , the alkaline agent is adjusted to pH 10 to 1
1 , at room temperature or at 40-50 ° C.
A method of adding waste nitric acid and aqueous hydrogen peroxide at the treatment temperature is used . Below, for these processing means it will be described.

First, when performing by controlling the pH value,
The pH value in the treatment tank containing the activated sludge to be treated is 4.5 or less, or a strong acidic state of 2.5 to 3.5, or the pH value in the treatment tank is 9.5 or more. Of 10-1
1 strong alkaline state. As a specific method of controlling the pH value, an alkali agent, an acid or a waste acid as described below is added to the treatment tank, and the pH value in the treatment tank is adjusted to be within the above range. Good.

In the method for treating organic wastewater of the present invention,
It is also effective to control the temperature in the treatment tank containing the activated sludge to be treated and to sterilize or lyse the bacteria constituting the activated sludge by heat. For example, the temperature in the treatment tank containing the activated sludge to be treated is set to 40 to 1
If controlled at 00 ° C, more preferably at 40 to 80 ° C,
As a result of denaturation or coagulation of proteins constituting the cell wall (membrane) or cytoplasm of the bacterium due to the heat, the bacterium is killed or impaired in function, so that the bacterium can be sterilized or lysed. In particular, considering the cost of heating, it is preferable to perform the treatment at about 40 to 50 ° C. In the method for treating organic wastewater of the present invention, as described above, only one of the methods of controlling the pH value in the treatment tank or controlling the temperature in the treatment tank as described above is used. Thereby, a part of the bacteria constituting the activated sludge can be sterilized or lysed. Further, the treatment may be performed under conditions in which both the pH value control and the temperature control are appropriately combined, and some of the bacteria constituting the activated sludge may be sterilized or lysed.

Further, in the method for treating organic wastewater of the present invention, an active agent is added to a treatment tank by adding an alkali agent, an acid or waste acid, or a compound having a bactericidal or lytic action to activated sludge. A part of bacteria constituting the sludge is sterilized or lysed. Examples of the alkaline agent used in this case include sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and ammonia. When these alkaline agents are added and treated in a treatment tank, the cell wall (membrane) of the bacteria constituting the activated sludge is damaged and destroyed, and has a large function of sterilizing or lysing the bacteria. Since the compound has the function of hydrolyzing the cytoplasm constituting bacteria to cause dysfunction and is an inexpensive compound, the intended object of the present invention described above can be easily and economically achieved. obtain.

The present inventors conducted the following simulation experiments in order to find the optimum treatment conditions when treating activated sludge using an alkaline agent. As a test method, first, a plurality of 1-liter measuring cylinders were prepared, and activated sludge was adjusted to 5,000 mg / liter in each measuring cylinder. Furthermore, milk was used as artificial wastewater, and BOD load was 1.0 kg / m ³
The mixture was added once a day so as to give a day, stirred well each time, and then aerated. And in the meantime, one a day
At normal temperature and at 40 ° C., 1000 mg of activated sludge was taken out and treated by adding an alkaline agent to each of the following pHs, and the treated sludge was returned to the original activated sludge. . Further, for comparison, a system not treated with an alkali agent was also performed in parallel. The processing conditions at this time are shown in Table 1.

[0019]

[Table 1]

As a result, when the alkaline agent is added to the activated sludge at room temperature, when the pH of the activated sludge treated with the alkaline agent added is 9.5 or more, the average sludge generation amount of the average sludge (G / day) was found to decrease. Further, it was found that the amount of the alkali agent added was smaller when the treatment was performed at 40 ° C. than when the treatment was performed at room temperature. Furthermore, as a result of the above examination, even when a part of the activated sludge is sterilized or lysed in this way, the purification ability is not reduced as much as in the case of the conventional organic wastewater treatment method. It could be confirmed.

In the method for treating organic wastewater of the present invention, an acid or waste acid is added to an activated sludge treatment tank (aeration tank) in place of the above-mentioned alkaline agent to remove bacteria constituting the activated sludge. Some may be sterilized or lysed. Examples of the acid used in this case include sulfuric acid, nitric acid, and hydrochloric acid. Further, waste acid discharged as waste from various factories and the like can be used effectively, and among them, waste nitric acid is particularly preferable. In the present invention, it is also possible to use waste sulfuric acid, waste hydrochloric acid, and the like that are discharged as waste from various factories and the like. When these acids or waste acids are treated with activated sludge, they have the function of causing damage to the cell walls (membrane) of the bacteria constituting the activated sludge and destroying them to sterilize or lyse the bacteria, and are inexpensive. Since the compound is a simple compound, the intended object of the present invention described above can be easily and economically achieved. As a result of detailed examination by the present inventors, in this case, of course, only by adding an acid, it is possible to sterilize or lyse a part of the bacteria constituting the activated sludge even at room temperature, as described above. As in the case of the alkaline agent, it was found that efficient treatment could be performed by controlling the temperature in the treatment tank to around 40 to 50 ° C.

Furthermore, in the method for treating organic wastewater of the present invention, activated sludge can be formed by adding any of the following compounds having a bactericidal action or a bacteriolytic action to activated sludge. Some of the bacteria that are being used can be sterilized or lysed. That is, in the activated sludge treatment tank containing the activated sludge to be treated, sorbic acid, sodium sorbate, potassium sorbate, calcium sorbate, aldehydes represented by glutaraldehyde, cationic surfactants, nonionic Surfactants, amphoteric surfactants, chlorine compounds, polyamines,
Aliphatic amines, phenols, nitrofurans, compounds having a trichloroalkylthio group, dithiocarbamates, alcohols, proteases, glucanases,
Amylase, magnesium monoperoxyphthalate,
By adding at least one compound selected from hydrogen peroxide, sodium peroxide, sodium percarbonate, and sodium carbide, a part of the bacteria constituting the activated sludge can be sterilized or lysed. Although these compounds have a bactericidal or lytic effect on activated sludge, they do not have strong toxicity and the drug effect is pH
It does not affect the properties of activated sludge such as dependence and temperature dependence, and is useful in terms of cost. Therefore, it can be suitably used in the method for treating organic wastewater of the present invention. The addition amount of these compounds is 0.1 to the activated sludge to be treated.
It is preferably about 5% by weight.

The above-mentioned compounds cause damage to the cell wall (membrane) of the bacteria constituting the activated sludge and cause the bacteria to lyse by destroying the cells, and also impair the function of the bacteria by oxidative decomposition of organic components. A function that causes functional sludge by binding to bacterial cell proteins, or by causing a functional disorder by denaturation or coagulation of a protein, or by inactivating or destroying an enzyme system or causing a metabolic disorder. It has various functions such as performing Therefore, if any one of these compounds is added and treated, a part of the bacteria constituting the activated sludge can be sterilized or lysed. However, in order to further improve the efficiency of the sterilization or lysis treatment, it is preferable to use these compounds in combination with the above-mentioned alkali agent, acid or waste acid. That is, if a compound having an appropriate function is selected from the above-listed compounds and used in combination with an alkali agent or an acid depending on the properties of the organic wastewater to be treated, treatment conditions, and the like, a function different from the alkali agent or the acid is obtained. Since the combined synergistic effect is obtained, it is possible to sterilize or lyse bacteria more efficiently. Therefore, a drug containing an alkali agent or an acid as a main component and prepared in combination with the compounds described above can be suitably used in the method for treating organic wastewater of the present invention. Further, it is also preferable to control the temperature in the activated sludge treatment tank and perform the treatment in a heated state.

Further, as an embodiment in which the above-mentioned compounds are used in combination with an alkali agent, an acid or a waste acid, for example, the following methods (1) to (3) can be adopted. Therefore, when preparing a chemical containing an alkaline agent or an acid as a main component for use in the method for treating organic wastewater of the present invention, an agent which can be conveniently used for these treatment methods is appropriately prepared. Is preferred.
Prior to alkali treatment (or acid treatment), after treatment with a combined compound, alkali treatment (or acid treatment)
Perform At the time of alkali treatment (or acid treatment), the compound is used in combination with an alkali agent (or acid) for treatment. After treatment with an alkali agent (or acid treatment), a treatment is performed by adding a combined compound.

In the method for treating organic wastewater of the present invention, for example, when an acid is used for disinfecting or dissolving activated sludge, sorbic acid, sodium sorbate, potassium sorbate, calcium sorbate, peracetic acid, etc. At least one selected from hydrogen oxide and sodium percarbonate
It is preferable to use a combination of species. A specific combination is, for example, a combination of nitric acid or hydrochloric acid and about 0.1 to 5% by weight of hydrogen peroxide. In consideration of economy and protection of the global environment, in this case, it is also a preferable embodiment to use waste nitric acid or waste hydrochloric acid, particularly waste nitric acid. In the method for treating organic wastewater of the present invention, particularly preferred combinations of an alkali agent and a compound used in combination therewith include, for example, a combination of an alkali agent and a cationic surfactant, a combination of an alkali agent and a chlorine compound, and an alkali agent. And a protease, a combination of an alkaline agent and glutaraldehyde, and the like.

Specific examples of the cationic surfactant used in combination with the alkali agent include di- or mono-long-chain alkyl, di- or tri-lower alkyl, and benzyl ammonium of a quaternary ammonium salt type cationic surfactant. Examples of such salts include dialkyldimethylammonium salts, alkyldimethylethylammonium salts, alkyltrimethylammonium salts, alkyldimethylbenzylammonium salts, and alkylamidopropyldimethylbenzylammonium salts. More specifically, for example, didecyl dimethyl ammonium chloride, dioctyl dimethyl ammonium chloride, benzethonium chloride, trimethoxysilyl propyl dimethyl octadecyl ammonium chloride,
Decyl isononyl dimethyl ammonium chloride can be used. Of course, other salts may be used.

Further, a pyridinium-type cationic surfactant such as an alkylpyridinium salt and an alkylquinolinium salt is also suitably used. For example, an alkylquinolinium chloride having 12 carbon atoms can be used. Furthermore,
Amphoteric surfactants such as alkyldi (aminoethyl) glycine hydrochloride and di (alkylaminodiethyl) glycine hydrochloride can also be used.

Further, in the present invention, specific compounds to be used in combination with the alkali agent include, in addition to the above, polyamines such as chlorhexidine hydrochloride and chlorhexidine gluconate (these are also organic chlorine compounds), chlorine dioxide, and the like. Inorganic chlorine compounds such as sodium hypochlorite are also effective. Furthermore, proteases such as papain and various enzymes such as glucanase and amylase can also be suitably used. In addition, aliphatic amines such as N-alkylenealkyldiamine, aldehydes such as glutaraldehyde, phenols such as cresol, hydrogen peroxide, peroxides such as sodium peroxide, sodium percarbonate, sodium carbide, monoperoxy Magnesium phthalate may also be used.

FIG. 2 shows a preferred system diagram of the organic wastewater treatment method of the present invention. As shown in FIG. 2, after the organic wastewater is introduced into the treatment tank and subjected to aeration treatment together with activated sludge. Extracting at least a part of the activated sludge from the treatment tank (aeration tank) or a sedimentation tank provided downstream of the treatment tank and introducing the activated sludge into the sludge treatment tank; The activated sludge is sterilized or lysed by appropriately controlling the activity of the activated sludge by adding a compound having a bactericidal or bacteriolytic action to the alkali agent, acid or waste acid, and activated sludge. The sludge is introduced into the treatment tank for the organic wastewater, and the aeration treatment is continued again. As a result, compared with the conventional organic wastewater purification system shown in FIG.
/ 100 can be reduced.

In the present invention, the activated sludge to be subjected to the sterilization or lysis treatment of bacteria in the sludge treatment tank may be in any treatment stage. For example, as in the example shown in FIG. 2, a part of the returned sludge returned from the sedimentation tank to the aeration tank is extracted and led to a sludge treatment tank, and the activated sludge is sterilized or lysed in the tank. Thereafter, the treatment sludge may be returned to the aeration tank to continue the treatment. As another embodiment, as shown in FIG. 3, when the treatment is performed by a batch activated sludge method without a settling tank, a part of the treated water in the aeration tank is extracted. It may be guided to a sludge treatment tank and sterilized or lysed by various sterilization or lysis treatment means. Further, in both of the examples shown in FIGS. 2 and 3, a sludge treatment tank is provided separately. However, for example, in the case of a household septic tank, an alkali agent,
Acid or waste acid, or a compound having a bactericidal or bacteriolytic action on activated sludge, or a combination thereof, an alkali agent, an acid or waste acid, particularly a chemical mainly composed of waste nitric acid may be added, This makes it possible to reduce the amount of excess sludge generated.

[0031]

Next, the present invention will be described in more detail with reference to Examples, Reference Examples and Comparative Examples of the present invention. < Reference Example 1> (Normal-temperature acid treatment) Using an 800 m ³ / day-scale treatment facility constructed according to the flow shown in FIG.
The organic wastewater from food factories dealing with the m ³ of dairy products was activated sludge treatment of organic waste water as raw water. Table 2 shows the properties of the raw water. In this embodiment, this raw water is subjected to the activated sludge concentration (MLSS) of 5,000 m in accordance with the flow shown in FIG.
It was aerated with activated sludge at g / l.

[0032]

[Table 2]

In the present reference example, a part of the returned sludge was withdrawn from the above process and introduced into the sludge treatment tank, and sulfuric acid was introduced into the sludge treatment tank to remove the bacteria constituting the activated sludge. Was sterilized or lysed. Return sludge concentration is 1
It was 0.00000 mg / l (about 1% concentration). This returned sludge was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr. Then, 75% sulfuric acid was added in the sludge treatment tank to adjust the pH in the sludge treatment tank to 3.0, and then sterilization or lysis was performed at normal temperature (20 ° C.). The treatment is completed with a residence time of 6 hours, and the activated sludge treated is treated with 800 m ³
In the aeration tank, and processed according to a normal processing flow.

As a result, the amount of excess sludge generated is about 40
kg / day. On the other hand, as shown in Comparative Example 1 to be described later, the surplus sludge amount in the conventional treatment method in which a treatment such as sterilization is not performed on a part of the returned sludge is 200 k.
g / day, and the amount of surplus sludge was clearly reduced by the method of this reference example. Also, it was examined the quality of the final treated water, as shown in Table 4, any no means inferior as compared with the case of treatment by the conventional method described in Comparative Example 1 to be described later, organic present embodiment It was confirmed that the purification ability did not decrease even in the wastewater treatment method. In the present reference example, the treatment amount of the activated sludge (concentration 10,000 mg / l) subjected to the sterilization or lysis treatment was 8
It was 0 m ³ / day. In this reference example, the amount of activated sludge that has been sterilized or lysed in the activated sludge treatment tank is determined as a ratio (ratio) to the total amount of activated sludge (4,000 kg / day) present in the treatment process. And 20%. Table 3 summarizes the processing conditions and the like of the examples, reference examples, and comparative examples.

<Embodiment 1 > (Normal-temperature alkali treatment) In the same manner as in Reference Example 1, a part of the returned sludge was withdrawn and introduced into the sludge treatment tank. By adding sodium, some of the bacteria constituting the activated sludge were sterilized or lysed. At this time, activated sludge having a concentration of about 1% was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr. Then, after adjusting the pH in the sludge treatment tank to 10.0 by adding 25% sodium hydroxide, sterilization or lysis treatment was performed at normal temperature (20 ° C.). 6
The treatment was terminated after a certain residence time, and the treated activated sludge was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 40 kg / day, and the amount of excess sludge could be reduced as in Reference Example 1. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. Also in this example, the amount of activated sludge subjected to sterilization or lysis treatment was 80 m ³ / day as in Reference Example 1, and the amount of activated sludge subjected to sterilization or lysis treatment for total activated sludge was 80 m ³ / day. The rate was likewise 20%. Table 3 summarizes the processing conditions of this example.

<Reference Example 2 > (Heat Treatment) In the same manner as in Reference Example 1, a part of the returned sludge was withdrawn and introduced into the sludge treatment tank. In this reference example, heated steam was introduced into the sludge treatment tank. Then, part of the bacteria constituting the activated sludge was sterilized or lysed by heat. About 1% of sludge is introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr,
The temperature in the sludge treatment tank was maintained at 70 ° C. to perform sterilization or bacteriolysis. The treatment was terminated after a residence time of 6 hours, the activated sludge treated was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 40 kg / day, and the amount of excess sludge could be reduced as in Reference Example 1. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. Also in this reference example, the amount of activated sludge subjected to sterilization or lysis treatment was 80 m ³ / day as in Reference Example 1, and the amount of activated sludge subjected to sterilization or lysis treatment for the total activated sludge was 80%. The rate was likewise 20%. Table 3 summarizes the processing conditions of this reference example.

<Reference Example 3 > (potassium sorbate addition treatment) In the same manner as in Reference Example 1, a part of the returned sludge was withdrawn and introduced into the sludge treatment tank. Potassium sorbate was added to a concentration of 0.3 g / liter, and a part of the bacteria constituting the activated sludge was sterilized or lysed. At this time, about 1 to the sludge treatment tank
% Activated sludge was introduced at a flow rate of ³ m ³ / hr. Then, sterilization or lysis treatment was performed at normal temperature (20 ° C.). 6
The treatment was terminated after a certain residence time, and the treated activated sludge was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of generated excess sludge was about 40 kg / day, and the amount of excess sludge could be reduced as in Reference Example 1. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. Also in this reference example, the amount of activated sludge subjected to sterilization or lysis treatment was 80 m ³ / day as in Reference Example 1, and the amount of activated sludge subjected to sterilization or lysis treatment for the total activated sludge was 80%. The rate was likewise 20%. Table 3 summarizes the processing conditions of this reference example.

<Reference Example 4 > (Addition treatment of glutaraldehyde) In this reference example, instead of potassium sorbate, glutaraldehyde was added to the sludge treatment tank at a rate of 0.3 g / liter to perform treatment. In the same manner as in Reference Example 3 , some of the bacteria constituting the activated sludge were sterilized or lysed. The activated sludge treated as described above is then
It was returned into the 800 m ³ aeration tank and processed according to the normal processing flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 40 kg / day, and the amount of excess sludge could be reduced as in Reference Example 1. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. Also in this reference example, the amount of activated sludge subjected to sterilization or lysis treatment was 80 m ³ / day as in Reference Example 1, and the amount of activated sludge subjected to sterilization or lysis treatment for the total activated sludge was 80%. The rate was likewise 20%. Table 3 summarizes the processing conditions of this reference example.

<Reference Example 5 > (Addition treatment of decylisononyldimethylammonium) In this reference example, decylisononyldimethylammonium was added to the sludge treatment tank in place of potassium sorbate.
Sun other than to be introduced to the process so as to 5g / liter
In the same manner as considered Example 3 were sterilized or lysis treatment of some bacteria that make up the activated sludge. The activated sludge treated as described above was then returned to an 800 m ³ aeration tank and treated according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 40 kg / day, and the amount of excess sludge could be reduced as in Reference Example 1. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. Also in this reference example, the amount of activated sludge subjected to sterilization or lysis treatment was 80 m ³ / day as in Reference Example 1, and the amount of activated sludge subjected to sterilization or lysis treatment for the total activated sludge was 80%. The rate was likewise 20%. Table 3 summarizes the processing conditions of this reference example.

<Embodiment 2 > (Acid treatment + potassium sorbate addition treatment) In the same manner as in Reference example 1, a part of the returned sludge was withdrawn and introduced into a sludge treatment tank. Potassium sorbate was added to the tank so as to have a concentration of 0.2 g / l, and the pH of the treatment tank was adjusted to 3.0 with waste nitric acid. Some were sterilized or lysed. At this time, activated sludge having a concentration of about 1% was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr. Then, sterilization or lysis treatment was performed at normal temperature (20 ° C.). The treatment is completed with a residence time of 4 hours, and the activated sludge treated is treated for 8 hours.
It was returned into the aeration tank of 00 m ³ and processed according to the normal processing flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 30 kg / day, and the amount of excess sludge could be reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this example, the amount of activated sludge subjected to the sterilization or lysis treatment was 6%.
It was 0 m ³ / day, and the rate of activated sludge subjected to sterilization or lysis treatment on the total activated sludge was 15%. Table 3
The following summarizes the processing conditions of this example. Furthermore, in this embodiment, the two compounds was performed treated state added, Example 1及beauty was subjected to treatment alone requirements
Compared with the case of ginseng Reference Example 1-5, it is possible efficient process, it is possible to shorten the residence time, moreover, efficient even with a small proportion of the activated sludge which processes of sterilization and the like processes It was found that the effect of reducing excess surplus sludge was obtained.

<Embodiment 3 > (Alkali agent + glutaraldehyde addition treatment) After a part of the returned sludge was withdrawn and introduced into the sludge treatment tank in the same manner as in Reference Example 1, the sludge treatment tank was used in this embodiment. Glutaraldehyde was added to the mixture so as to have a concentration of 0.2 g / l, and the pH was adjusted to 10.1 with 25% sodium hydroxide.
It adjusted so that it might be set to 0, and some bacteria which comprise the activated sludge were sterilized or lysed. At this time, activated sludge having a concentration of about 1% was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr. Then, sterilization or lysis treatment was performed at normal temperature (20 ° C.). The treatment was completed after a residence time of 3 hours, the treated activated sludge was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 30 kg / day, and the amount of excess sludge could be reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this example, the amount of activated sludge subjected to the sterilization or lysis treatment was 6%.
It was 0 m ³ / day, and the rate of activated sludge subjected to sterilization or lysis treatment on the total activated sludge was 15%. Table 3
The following summarizes the processing conditions of this example. Furthermore, in this embodiment, the two compounds was performed treated state added, Example 1及beauty was subjected to treatment alone requirements
Compared with the case of ginseng Reference Example 1-5, it is possible efficient process, it is possible to shorten the residence time, moreover, efficient even with a small proportion of the activated sludge which processes of sterilization and the like processes It was found that the effect of reducing excess surplus sludge was obtained.

Reference Example 6 (Addition of Alkali Agent + Decylisononyldimethylammonium) In the same manner as in Reference Example 1, a part of the returned sludge was withdrawn and introduced into a sludge treatment tank. Activated sludge is prepared by charging decyl isononyl dimethyl ammonium into the sludge treatment tank so that the concentration becomes 0.3 / liter, and further adjusting the pH to 9.0 with 25% sodium hydroxide. Some of the bacteria were sterilized or lysed.
At this time, about 1% concentration of activated sludge was fed into the sludge treatment tank for 3m.
^It was introduced at a flow rate of ³ / hr. Then, sterilization or lysis treatment was performed at normal temperature (20 ° C.). The treatment was completed with a residence time of 4 hours, the activated sludge treated was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 30 kg / day, and the amount of excess sludge could be reduced. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this reference example, the amount of activated sludge subjected to sterilization or lysis treatment was 6
It was 0 m ³ / day, and the rate of activated sludge subjected to sterilization or lysis treatment on the total activated sludge was 15%. Table 3
The following summarizes the processing conditions of this reference example. Furthermore, the case of the Reference Example, two kinds of compounds have been subjected to conditions in the process is added, Example 1及beauty was subjected to treatment alone requirements
Compared with the case of ginseng Reference Example 1-5, it is possible efficient process, it is possible to shorten the residence time, moreover, efficient even with a small proportion of the activated sludge which processes of sterilization and the like processes It was found that the effect of reducing excess surplus sludge was obtained.

<Embodiment 4 > (Heat treatment + acid treatment) In the same manner as in Reference Example 1, a part of the returned sludge was withdrawn and introduced into the sludge treatment tank. Steam was introduced and heated, and the pH was adjusted to 3.0 with 75% sulfuric acid to partially sterilize or lyse bacteria constituting the activated sludge. At this time, activated sludge having a concentration of about 1% was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr, and sterilization or lysis was performed at 50 ° C. 4
The treatment was terminated after a certain residence time, and the treated activated sludge was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 20 kg / day, and the amount of excess sludge could be significantly reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this example, the amount of the activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Met. Table 3 summarizes the processing conditions of this example. Furthermore, in the present embodiment has performed the process in a state of adding the two kinds of requirements, including a heat treatment, as compared with Example 1及beauty ginseng Reference Example 1-5 was subjected to treatment alone requirements Thus, it was found that the residence time can be shortened and the same effect can be obtained even if the ratio of the activated sludge to be treated is small. In addition, the same effect can be obtained even if the ratio of the activated sludge to be sterilized or lysed is smaller than that of Examples 2 and 3 and Reference Example 6 in which the treatment is performed by adding two kinds of compounds, and the efficiency is improved. I found it good.

<Embodiment 5 > (Heat treatment + alkaline agent treatment) In the same manner as in Reference Example 1, a part of the returned sludge was withdrawn and introduced into the sludge treatment tank. Heating was conducted by introducing heated steam, and the pH was adjusted to 10.0 with 25% sodium hydroxide to partially sterilize or lyse the bacteria constituting the activated sludge. At this time, activated sludge having a concentration of about 1% was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr, and sterilization or lysis was performed at 50 ° C. The treatment was completed with a residence time of 4 hours, the activated sludge treated was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 20 kg / day, and the amount of excess sludge could be greatly reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this example, the amount of the activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Met. Table 3 summarizes the processing conditions of this example. Furthermore, in the present embodiment has performed the process in a state of adding the two kinds of requirements, including a heat treatment, as compared with Example 1及beauty ginseng Reference Example 1-5 was subjected to treatment alone requirements Thus, it was found that the residence time can be shortened and the same effect can be obtained even if the ratio of the activated sludge to be treated is small. In addition, the same effect can be obtained even if the ratio of the activated sludge to be sterilized or lysed is smaller than that of Examples 2 and 3 and Reference Example 6 in which the treatment is performed by adding two kinds of compounds, and the efficiency is improved. I found it good.

<Reference Example 7 > (Heat treatment + potassium sorbate addition treatment) A part of the returned sludge was withdrawn in the same manner as in Reference Example 1 and introduced into the sludge treatment tank. Heating steam was introduced into the reactor, and the mixture was heated. Further, potassium sorbate was added at a concentration of 0.2 g / liter to sterilize or lyse a part of the bacteria constituting the activated sludge.
At this time, about 1% concentration of activated sludge was fed into the sludge treatment tank for 3m.
^The mixture was introduced at a flow rate of ³ / hr, and sterilized or lysed at 50 ° C. The treatment was completed with a residence time of 4 hours, the activated sludge treated was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above-described treatment, the amount of generated excess sludge was about 20 kg / day, and the amount of excess sludge could be significantly reduced. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this reference example, the amount of the activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Met. Table 3 summarizes the processing conditions of this example. Furthermore, in the case of the present embodiment has been performed processing while adding the two requirements including heat treatment, compared with the case of Example 1及beauty ginseng Reference Example 1-5 was subjected to treatment alone requirements Thus, it was found that the residence time can be shortened and the same effect can be obtained even if the ratio of the activated sludge to be treated is small. In addition, the same effect can be obtained even if the ratio of the activated sludge to be sterilized or lysed is smaller than that of Examples 2 and 3 and Reference Example 6 in which the treatment is performed by adding two kinds of compounds, and the efficiency is improved. I found it good.

<Embodiment 8 > (Heat treatment + glutaraldehyde addition treatment) A part of the returned sludge was pulled out and introduced into the sludge treatment tank in the same manner as in Reference Example 1. The mixture was heated by introducing heated steam into it, and glutaraldehyde was further added thereto at a concentration of 0.2 g / liter to sterilize or lyse a part of the bacteria constituting the activated sludge.
At this time, about 1% concentration of activated sludge was fed into the sludge treatment tank for 3m.
^The mixture was introduced at a flow rate of ³ / hr, and sterilized or lysed at 50 ° C. The treatment was completed with a residence time of 4 hours, the activated sludge treated was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above treatment, the amount of excess sludge generated was about 20 kg / day, and the amount of excess sludge could be significantly reduced. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this reference example, the amount of activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Met. Table 3 summarizes the processing conditions of this reference example. Furthermore, in the case of the present embodiment has been performed processing while adding the two requirements including heat treatment, compared with the case of Example 1及beauty ginseng Reference Example 1-5 was subjected to treatment alone requirements Thus, it was found that the residence time can be shortened and the same effect can be obtained even if the ratio of the activated sludge to be treated is small. In addition, the same effect can be obtained even if the ratio of the activated sludge to be further sterilized or lysed is smaller than in the case of Examples 2 and 3 and Reference Example 6 in which the treatment is performed by adding two kinds of compounds, and the efficiency is improved. I found it good.

<Reference Example 9 > (Heat treatment + decylisononyldimethylammonium addition treatment) A part of the returned sludge was withdrawn in the same manner as in Reference Example 1 and introduced into the sludge treatment tank. Heating steam is introduced into the treatment tank to heat it, and decylisononyldimethylammonium is further added at a rate of 0.3 g / liter to sterilize or lyse some of the bacteria constituting the activated sludge. did. At this time, activated sludge having a concentration of about 1% was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr, and sterilization or lysis was performed at 50 ° C. The treatment was completed with a residence time of 4 hours, the activated sludge treated was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above-mentioned treatment, the amount of excess sludge generated was about 20 kg / day, and the amount of excess sludge could be significantly reduced. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. In this reference example, the amount of the activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Met. Table 3 summarizes the processing conditions of this reference example. Furthermore, in the case of the present embodiment has been performed processing while adding the two requirements including heat treatment, compared with the case of Example 1及beauty ginseng Reference Example 1-5 was subjected to treatment alone requirements Thus, it was found that the residence time can be shortened and the same effect can be obtained even if the ratio of the activated sludge to be treated is small. In addition, it can be seen that the same effect can be obtained even when the ratio of the activated sludge to be sterilized or lysed is smaller than that in Examples 2 and 3 and Reference Example 6 in which the treatment is performed by adding two kinds of compounds. Was.

<Example 6 > (Heat treatment + acid treatment + potassium sorbate addition) A part of the returned sludge was withdrawn in the same manner as in Reference Example 1 and introduced into a sludge treatment tank. Heating steam is introduced into the treatment tank and heated, and potassium sorbate is added so as to have a concentration of 0.1 g / liter, and the pH is further adjusted to be 3.0 with 75% sulfuric acid. Some of the constituting bacteria were sterilized or lysed. At this time, about 1% concentration of activated sludge was supplied to the sludge treatment tank at 3 m ³ /
The mixture was introduced at a flow rate of hr and sterilized or lysed at 50 ° C. The treatment was completed after a residence time of 3 hours, the treated activated sludge was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above-described treatment, the amount of generated excess sludge was almost 0 kg / day, and the amount of excess sludge could be further reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. or,
In this example, the amount of the activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Was. Table 3 summarizes the processing conditions of this example.
Further, in the case of the present embodiment, the treatment was performed in a state where three kinds of requirements including heat treatment were added. However, compared with the case where the treatment was performed alone or in a state where two kinds of requirements were added, the residence time was reduced. It turns out that it can be shortened. Moreover, it was found that the amount of surplus sludge could be reduced to almost zero, and the effect of reducing the amount was large.

<Example 7 > (Heat treatment + alkali agent + glutaraldehyde addition) A part of the returned sludge was pulled out and introduced into the sludge treatment tank in the same manner as in Reference Example 1, and then, in this example, the sludge treatment was performed. Heating steam is introduced into the tank and heated. Glutaraldehyde is added so as to have a concentration of 0.1 g / liter, and the pH is adjusted to 10.0 with 25% sodium hydroxide. Some of the constituting bacteria were sterilized or lysed. At this time, activated sludge having a concentration of about 1% was introduced into the sludge treatment tank at a flow rate of ³ m ³ / hr, and sterilization or lysis was performed at 50 ° C. The treatment was completed after a residence time of 3 hours, the treated activated sludge was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above-mentioned treatment, the amount of generated excess sludge was almost 0 kg / day, and the amount of excess sludge could be further reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. or,
In this example, the amount of the activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Was. Table 3 summarizes the processing conditions of this example.
Further, in the case of the present embodiment, the treatment was performed in a state where three kinds of requirements including heat treatment were added. However, compared with the case where the treatment was performed alone or in a state where two kinds of requirements were added, the residence time was reduced. It turns out that it can be shortened. Moreover, it was found that the amount of surplus sludge could be reduced to almost zero, and the effect of reducing the amount was large.

<Reference Example 10 > (Heat treatment + alkali agent + decylisononyldimethylammonium addition) In the same manner as in Reference Example 1, part of the returned sludge was withdrawn and introduced into a sludge treatment tank. Heating steam is introduced into the sludge treatment tank and heated, and decylisononyldimethylammonium is added so as to have a concentration of 0.1 g / liter, and the pH is further adjusted to 9.0 with 25% sodium hydroxide. After the preparation, a part of the bacteria constituting the activated sludge was sterilized or lysed. At this time, about 1 to the sludge treatment tank
% Activated sludge at a flow rate of ³ m ³ / hr, 50
Sterilization or lysis treatment was performed at ℃. The treatment was completed after a residence time of 3 hours, the treated activated sludge was returned to the 800 m ³ aeration tank, and the treatment was performed according to a normal treatment flow.

As a result of performing the above-described treatment, the amount of generated excess sludge was almost 0 kg / day, and the amount of excess sludge could be further reduced. In addition, when the final treated water was examined, as shown in Table 4, the treated organic wastewater of the present reference example was comparable to the case treated by the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. or,
In this reference example, the amount of the activated sludge subjected to the sterilization or lysis treatment was 50 m ³ / day, and the ratio of the activated sludge subjected to the sterilization or lysis treatment to the total activated sludge was 12.5%. Was. Table 3 summarizes the processing conditions of this reference example.
Furthermore, in the case of this reference example, the treatment was performed in a state where three types of requirements including heat treatment were added, but the residence time was shorter than in the case where the treatment was performed alone or in a state where two types of requirements were added. I found that I could do it. Moreover, it was found that the amount of surplus sludge could be reduced to almost zero, and the effect of reducing the amount was large.

Example 8 Without providing the settling tank shown in FIG. 3, a predetermined amount of activated sludge was withdrawn from the aeration tank and put into the sludge treatment tank for treatment, and then the treated sludge was returned to the aeration tank. in batchwise activated sludge treatment systems, other than for processing by 80 m ³ introduced once the activated sludge to the sludge treatment tank when the waste water process, was subjected to activated sludge treatment of organic wastewater in the same manner as in reference example 1 . As a result of performing the above processing, the amount of excess sludge generated is about 40 k
g / day, and as shown in Table 3, it was confirmed that the amount of excess sludge can be reduced even in the batch type activated sludge treatment system. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method.

Comparative Example 1 Activated sludge treatment of organic wastewater was carried out in the same manner as in Example 8 , except that a part of the activated sludge from the aeration tank was not treated with the alkaline agent. As a result, as shown in Table 4, the amount of excess sludge generated was 200 kg / day, and the amount of excess sludge generated was at least 5 times or more as compared with the case of the example.

<Example 9 > The same organic wastewater as that used in Reference Example 1 from a food factory that handles dairy products was treated with activated sludge of organic wastewater. In the present embodiment, a part of the returned sludge is withdrawn and introduced into the sludge treatment tank, and in the sludge treatment tank, waste nitric acid and
Activated sludge was solubilized by adding a hydrogen peroxide solution and lysing. At this time, the input amount of the hydrogen peroxide solution was 5 kg, which corresponded to about 1.3% by weight based on the activated sludge to be treated. 12m at a time to sludge treatment tank
Activated sludge in an amount of ³ was introduced, waste nitric acid was added until the pH reached 3, and the mixture was stirred at 20 ° C. for 4 hours. Then, the treated activated sludge was returned to the aeration tank having a capacity of 800 m ³ again.

As a result of performing the above-mentioned treatment, the amount of generated excess sludge was about 30 kg / day, and the amount of excess sludge could be reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. The amount of activated sludge subjected to sterilization or lysis treatment is 60 m ³ / day,
The rate of the activated sludge subjected to the sterilization or lysis treatment on the total activated sludge was 15%. Table 3 summarizes the processing conditions of this example. Furthermore, in the present embodiment has performed the processing in a state with the addition of two compounds containing waste nitric acid, even in this case, Embodiment 1及beauty ginseng Reference Example 1 was subjected to treatment with a single condition as compared with the case of 1-5, it was found that the same effect can be obtained even with a small proportion of the activated sludge to be sterilized or lysis treatment. According to this embodiment, more economical treatment can be achieved by using waste nitric acid.

[0071] was subjected to activated sludge treatment of organic wastewater of the organic wastewater from <Example 1 0> food factory dealing with the same dairy products as used in Reference Example 1 as the raw water. In the present embodiment, a part of the returned sludge is withdrawn and introduced into the sludge treatment tank, and in the sludge treatment tank, waste nitric acid and
Activated sludge was solubilized by adding a hydrogen peroxide solution and lysing. At this time, the input amount of the hydrogen peroxide solution was 5 kg, which corresponded to about 1.3% by weight based on the activated sludge to be treated. 12m at a time to sludge treatment tank
Activated sludge in an amount of ³ was introduced, waste nitric acid was added until the pH reached 3, and sterilization or lysis was performed at 40 ° C. The treatment was terminated after a residence time of 3 hours, and the treated activated sludge was returned to the aeration tank having a capacity of 800 m ³ again.

As a result of performing the above treatment, the amount of excess sludge generated was about 20 kg / day, and the amount of excess sludge could be reduced. In addition, when the final treated water was examined, as shown in Table 4, the treatment of the organic wastewater of the present example was not inferior to that of the conventional method described in Comparative Example 1 described below. It was confirmed that the purification ability did not decrease even in the method. The amount of activated sludge subjected to the sterilization or lysis treatment is 50 m ³ / day,
The ratio of the activated sludge subjected to the sterilization or lysis treatment on the total activated sludge was 12.5%. Table 3 summarizes the processing conditions of this example. Furthermore, in the case of the present embodiment, the treatment was performed in a state where three types of requirements including heat treatment were added, but the residence time was shorter than in the case where the treatment was performed alone or in a state where two types of requirements were added. I found that I could do it. Moreover, it was found that the amount of surplus sludge could be reduced to almost zero, and the effect of reducing the amount was large. Further, with the configuration as in this embodiment, more economical treatment can be achieved by using waste nitric acid.

[0073]

[Table 3]

[0074]

[Table 4]

[0075]

As described above, according to the present invention, in the treatment of organic wastewater using the activated sludge method, the amount of excess sludge generated without deteriorating the quality of treated water discharged in the final stage is reduced. Can be greatly reduced, and the purification treatment of the organic wastewater can be performed easily and economically.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an action of a factor having a bactericidal action or a lytic action on activated sludge used in the present invention.

FIG. 2 is a schematic system diagram showing an example of a method for treating organic wastewater of the present invention.

FIG. 3 is a schematic system diagram showing another example of the method for treating organic wastewater of the present invention.

FIG. 4 is an example of a processing flow of a conventional method for treating organic wastewater.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-10-128376 (JP, A) JP-A-53-135168 (JP, A) JP-A-8-24886 (JP, A) JP-A-6-128 71286 (JP, A) JP-A-4-74595 (JP, A) JP-A-9-75976 (JP, A) JP-A-7-116686 (JP, A) JP-A-8-309382 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C02F 3/12

Claims (9)

(57) [Claims] When an organic wastewater is subjected to purification treatment using activated sludge, a treatment temperature of 40 to 40 is used in any of the treatment steps.
At 50 ° C. , by adding an acid or waste acid so as to have a pH of 2.5 to 3.5, a part of the bacteria constituting the activated sludge is sterilized or lysed, and the activated sludge grows during the treatment process. A method for treating organic wastewater, comprising: 2. When the organic wastewater is subjected to purification treatment using activated sludge, in any of the treatment steps, it is carried out at room temperature or at 40 to 40 ° C.
At a treatment temperature of 50 ° C., by adding an alkaline agent so as to have a pH of 10 to 11, a part of the bacteria constituting the activated sludge is sterilized or lysed to suppress the growth of the activated sludge during the treatment process. A method for treating organic wastewater. 3. When the organic wastewater is subjected to purification treatment using activated sludge, in any of the treatment steps, it is carried out at room temperature or at 40 to 40 ° C.
At a treatment temperature of 50 ° C., by adding waste nitric acid and aqueous hydrogen peroxide, part of the bacteria constituting the activated sludge is sterilized or lysed to suppress the growth of the activated sludge during the treatment process. A method for treating organic wastewater. The addition of 4. A acid or waste acid, after aeration with activated sludge by introducing the organic waste water into the treatment tank, provided downstream of the or the processing tank from the above treatment tank (aeration tank) In the activated sludge treatment tank into which the activated sludge extracted from the settling tank is introduced, the activated sludge is sterilized or lysed in the treatment tank, and the treated activated sludge is introduced into the treatment tank. 2. The method for treating organic wastewater according to claim 1, wherein 5. An organic wastewater treatment by adding an alkali agent.
After being introduced into the tank and aerated with activated sludge, the above treatment
Installed in the tank (aeration tank) or downstream of the treatment tank
Activated sludge extracted from the settling tank
This is performed in an activated sludge treatment tank, and the activated sludge is removed in the treatment tank.
After sterilization or lysis, the treated activated sludge is treated in the above treatment tank.
3. The method for treating organic wastewater according to claim 2, which is introduced into the inside.
Law. 6. The method according to claim 1, wherein the waste nitric acid and the aqueous hydrogen peroxide are added to an organic solvent.
And aerated with activated sludge and introduced a sexual wastewater treatment tank
Later, from inside the processing tank (aeration tank) or downstream of the processing tank
Activated sludge extracted from the sedimentation tank provided on the side
In the activated sludge treatment tank
Activated sludge treated after sterilizing or lysing activated sludge with
The organic waste according to claim 3, wherein the organic waste is introduced into the processing tank.
Water treatment method. 7. A drug for sterilizing or lysed some bacteria constituting the activated sludge used in the treatment method of organic wastewater according to claim 1 or claim 4,
Agent, characterized in that the main component of the acid or waste acid. 8. The organic waste according to claim 2 or claim 5.
Activated sludge used in water treatment methods
An agent for disinfecting or lysing some of the bacteria,
A drug characterized by containing an alkali agent as a main component. 9. The organic waste according to claim 3 or claim 6.
Activated sludge used in water treatment methods
An agent for disinfecting or lysing some of the bacteria,
Characterized by waste nitric acid and hydrogen peroxide
Drug.