JP4645568B2 - Microbial acclimatization apparatus, wastewater treatment apparatus, microorganism acclimatization method and wastewater treatment method - Google Patents

Description

  The present invention relates to a microbial habituation apparatus and a microbial habituation method for acclimatizing microorganisms used when biologically decomposing organic matter in wastewater to high-temperature effluent, and a wastewater treatment apparatus and a wastewater treatment method using them. .

  Various treatment methods for domestic wastewater such as sewage and human waste, and wastewater containing organic matter discharged from manufacturing processes such as food processing factories and chemical industries have been proposed. Among them, the activated sludge method is mentioned as the most general method. In the activated sludge method, wastewater containing organic matter is supplied to a treatment tank in which sludge, which is an aerobic microorganism, floats, and aerated with air to oxidize and decompose the organic matter in the wastewater by microorganisms that constitute the suspended sludge. Is the method. Here, as microorganisms to be used, in general, many microorganisms have a suitable growth temperature of 25 to 37 ° C.

  By the way, it is known that the activity of microorganisms depends on the water temperature, and when the water temperature rises by 10 ° C., the treatment activity becomes about twice as high. In view of this, when the organic matter contained in the wastewater is biologically treated, it is advantageous to set the water temperature high in terms of the activity of microorganisms. However, when the water temperature exceeds 40 ° C., the activity is remarkably lowered due to the denaturation of the protein constituting the microorganism and the deactivation of the enzyme, and the quality of the treated water is deteriorated. For this reason, in general, biological treatment facilities that employ the activated sludge method are operated with the temperature of the wastewater used for treatment being kept at 40 ° C. or lower (see Non-Patent Document 1).

  However, in recent years, especially in the summer, the temperature of wastewater used for wastewater treatment by the activated sludge method has risen, and high temperature wastewater is often discharged daily at food processing factories and chemical factories. When high temperature wastewater flows in this way, the water temperature in the biological treatment tank rises significantly, sometimes exceeding 40 ° C., and the quality of the treated water may be significantly deteriorated. For such problems, conventionally, a large amount of cooling water is poured into the biological treatment tank to lower the temperature of the water in the biological treatment tank, or the inflowing waste water is cooled to a temperature of 40 ° C. or lower before the biological treatment tank. A supply method has been proposed (see Patent Document 1).

JP-A-8-155475 “Activated sludge method and maintenance management” 5th edition, Industrial Water Research Committee, May 24, 1994, p59, p227

  However, the conventional countermeasures against the inflow of high temperature wastewater have various problems on an actual scale. For example, in order to inject a large amount of cooling water, it is necessary to increase the size of the treatment tank, or in order to cool the inflow wastewater before supplying it to the biological treatment tank, a separate cooling facility is required. There is a problem that energy costs for cooling occur. Therefore, even if the temperature of the water in the biological treatment tank exceeds 40 ° C, which is generally considered undesirable for the growth of microorganisms, due to an increase in the drainage temperature or an increase in the air temperature, the equipment change (upsizing) and treatment costs There is a need for measures that can efficiently treat organic wastewater without increasing operating costs.

  As a method for acclimatizing microorganisms to a high temperature environment in order to enable wastewater to be treated at a high temperature, the present inventors gradually target a temperature environment from a temperature environment suitable for the growth of microorganisms. (See the comparative example described later). As a result, as the microorganisms adapted to the high temperature environment, the treatment activity gradually improved and the quality of the treated water was recovered. However, when the temperature is gradually raised from the preferred temperature environment of the microorganism, if it reaches a temperature range exceeding 40 ° C., which is generally considered undesirable for the growth of the microorganism, the microorganism cannot adapt well to the new environment. However, the treatment activity decreased, and the quality of treated water temporarily deteriorated. If the fluctuation in treatment activity is large in this way, treated water with poor water quality cannot be discharged as it is, and it is necessary to temporarily store it in a storage tank and reprocess it. Will be invited.

  Then, the subject of this invention is the waste water treatment apparatus and waste water treatment method which can process a high temperature organic waste water stably and efficiently, without accompanying the change of an installation or a rise in processing cost, and the high temperature used for these. It is an object of the present invention to provide a microorganism habituation apparatus and a microorganism habituation method for obtaining microorganisms acclimated to drainage.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have stably used even in a high-temperature environment by using wastewater discharged at a high temperature in a conventionally used wastewater treatment tank. After acclimatizing microorganisms so that organic wastewater can be treated efficiently, it was conceived that treatment of high-temperature wastewater was continued, and a specific apparatus and method for realizing these on a real machine scale were found. It came to be completed.

That is, the present invention has the following configuration.
(1) A device for acclimatizing microorganisms used for aerobically decomposing organic matter in high-temperature wastewater to high-temperature wastewater, in which high-temperature wastewater flows from one end and is discharged from the other end And cooling means attached to the wastewater treatment tank, for cooling the high temperature wastewater and forming a high temperature drainage area and a medium temperature drainage area in the wastewater treatment tank along the flow direction of the high temperature wastewater, and sludge containing microorganisms A microorganism acclimatization apparatus comprising a sludge circulation means for circulation between a high temperature drainage area and a medium temperature drainage area.
(2) The microorganism acclimatization apparatus according to (1), wherein the temperature of the high-temperature drainage and the high-temperature drainage zone is higher than 40 ° C and lower than 45 ° C, and the temperature of the intermediate-temperature drainage zone is 40 ° C or less.
(3) An apparatus for acclimatizing microorganisms to high-temperature wastewater and aerobically decomposing organic matter in the high-temperature wastewater by the microorganisms, in which high-temperature wastewater flows from one end and treated water is discharged from the other end. A wastewater treatment tank, a cooling means attached to the wastewater treatment tank, for cooling the high temperature wastewater and forming a high temperature drainage area and a medium temperature drainage area in the wastewater treatment tank along the flow direction of the high temperature wastewater, and a microorganism A sludge circulation means that circulates the sludge contained between the high temperature drainage area and the intermediate temperature drainage area, and further has means for stopping cooling in the wastewater treatment tank after the microorganisms acclimatize to the high temperature drainage. Wastewater treatment equipment.
(4) The waste water treatment apparatus according to (3), wherein the temperature of the high temperature waste water and the high temperature waste water region is higher than 40 ° C. and lower than 45 ° C., and the temperature of the medium temperature waste water region is 40 ° C. or less.

(5) In the process of injecting high temperature wastewater from one end of the wastewater treatment tank and discharging from the other end, the high temperature wastewater is cooled and the high temperature drainage area and the intermediate temperature drainage area are placed in the wastewater treatment tank in the flow direction of the high temperature wastewater. A method of acclimatizing microorganisms, characterized in that sludge is circulated between the high temperature drainage area and the medium temperature drainage area.
(6) The microorganism acclimatization method according to (5), wherein the temperature of the high-temperature drainage and the high-temperature drainage zone is higher than 40 ° C and lower than 45 ° C, and the temperature of the intermediate-temperature drainage zone is 40 ° C or lower.
(7) The above (5), wherein the time per one time that the sludge passes through the high temperature drainage area and the intermediate temperature drainage area is 1 hour to 3 days, and the period of acclimatization of the sludge is 0.5 to 60 days (6) The method of acclimatizing microorganisms as described.
(8) A wastewater treatment method for aerobically decomposing organic matter in high-temperature wastewater with microorganisms, wherein the microorganisms are adapted to acclimatize the microorganisms by the microorganism acclimatization method according to any one of (5) to (7). And a decomposition treatment step of treating the high-temperature wastewater with sludge containing microorganisms acclimatized in the microorganism conditioning step after stopping the cooling in the wastewater treatment tank after the microorganism conditioning step. Processing method.

  According to the present invention, it is possible to stably and efficiently decompose organic matter in wastewater even in a high temperature environment which is generally considered unfavorable for the growth of microorganisms, without accompanying changes in equipment and rising processing costs. There is an effect that a microorganism that can be produced is obtained, and that high-temperature organic waste water can be efficiently treated without causing fluctuations in the treatment activity.

Hereinafter, the present invention will be described in detail.
The waste water in the present invention is an organic matter-containing waste water, and examples thereof include domestic waste water such as sewage and human waste, and waste water containing specific organic matter such as food processing factories and chemical industries. Although the kind of organic substance contained in this waste water is not specifically limited, Generally, easily degradable organic substances such as carbohydrates, sugars, and organic acids can be mentioned.

The microorganism in the present invention is not particularly limited as long as it is a microorganism that aerobically decomposes organic matter in waste water, and may be any microorganism generally used in activated sludge facilities. As described above, when the water temperature exceeds 40 ° C., the treatment activity of such a general microorganism is remarkably lowered due to denaturation of the protein constituting the microorganism or inactivation of the enzyme. In order to decompose organic matter in a high temperature environment exceeding 45 ° C., it is necessary to acclimate the microorganisms to this high temperature environment.
The sludge in the present invention is not particularly limited, and contains sludge, and what is generally used in activated sludge facilities may be used.

The microorganism acclimatization apparatus of the present invention includes a waste water treatment tank, a cooling means, and a sludge circulation means, and adapts microorganisms used for aerobically decomposing organic matter in the high temperature waste water to the high temperature waste water. In addition to these, the waste water treatment apparatus of the present invention further comprises means for stopping cooling in the waste water treatment tank (cooling stop means), and aerobic organic matter in the high temperature waste water by microorganisms acclimatized to the high temperature waste water. It decomposes automatically.
Hereinafter, embodiments of the microorganism habituation apparatus and the wastewater treatment apparatus of the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto.

  Fig.1 (a) is the figure which showed typically one Embodiment of the microorganisms acclimatization apparatus and waste water treatment apparatus concerning this invention, FIG.1 (b) planarly viewed the apparatus of Fig.1 (a). It is a schematic diagram.

  1 (a) and 1 (b), a flow path is formed in one end to the other end of the aeration tank 1, which is a waste water treatment tank, by alternately providing partition plates 10 on opposing side walls. In addition, a drainage introduction pipe 3 for injecting drainage A is attached. Thus, the high temperature waste water A flows in from one end of the waste water treatment tank (aeration tank 1) and is discharged from the other end.

  The flow path formed in the waste water treatment tank (aeration tank 1) is provided with a cooling water introduction pipe 4 as a cooling means. By injecting the cooling water B from the cooling water introduction pipe 4, a high temperature can be obtained. The drainage A is cooled, and a high temperature drainage area and a medium temperature drainage area can be formed in the drainage treatment tank (aeration tank 1) along the flow direction of the high temperature drainage A. The cooling means, that is, the cooling water introduction pipe 4 is provided at an arbitrary position between one end and the other end of the waste water treatment tank (aeration tank 1), preferably at an almost intermediate position. That is, with the position where the cooling means is provided as a boundary, the upstream is a high temperature drainage area and the downstream is a medium temperature drainage area. As the cooling water B injected from the cooling water introduction pipe 4, it is preferable to use ground water, industrial water, river water or the like that does not require energy cost for cooling.

  The waste water treatment tank (aeration tank 1) contains sludge containing microorganisms. As a sludge circulation means for circulating this sludge between a high temperature drainage area and a medium temperature drainage area, a wastewater treatment tank (aeration tank 1). ), The solid-liquid separation unit 2 that settles and separates sludge from the waste water discharged from the other end (treated water when the organic matter contained therein is decomposed), and the aerated tank as the returned sludge D. 1 is provided with a sludge return pump 6 for returning to one end. In addition, when surplus sludge increases in the wastewater treatment tank (aeration tank 1) as the treatment progresses, the sludge that has been separated by settling is separated as necessary while considering the MLSS concentration in the wastewater treatment tank. Part of it can be extracted as excess sludge. In addition, the waste water after the sludge is settled and separated in the solid-liquid separation unit 2 (treated water when the contained organic matter is decomposed) is discharged from the treated water discharge pipe 5 as treated water C.

  Further, although not shown in FIGS. 1A and 1B, the cooling water introduction pipe 4 is provided with a valve for stopping the supply of cooling water as cooling stop means. As a result, cooling can be stopped after microorganisms have acclimatized to high temperature drainage, and the medium temperature drainage area can be heated to the same temperature as the high temperature drainage area to perform wastewater treatment. Can also be used.

  Further, normally, an air supply pipe 7 is provided at the bottom of the wastewater treatment tank (aeration tank 1) for supplying air necessary for microorganisms to aerobically decompose organic matter in the wastewater A. Yes.

  The temperature of the high-temperature drainage area formed by the high-temperature drainage A flowing into the wastewater treatment tank (aeration tank 1) and the cooling means is preferably more than 40 ° C and less than 45 ° C, and on the other hand, by the cooling means The temperature of the formed intermediate temperature drainage zone is preferably 40 ° C. or lower. Furthermore, especially when used as a habituation device, if the temperature difference between the high temperature drainage area and the medium temperature drainage area is too large, the processing activity of microorganisms in the high temperature drainage tends to be reduced, The temperature difference between the high temperature drainage area and the medium temperature drainage area is preferably 10 ° C. or less.

FIG. 2 is a diagram schematically showing another embodiment of the microorganism habituation apparatus and the waste water treatment apparatus according to the present invention.
In FIG. 2, the waste water treatment tank has a structure in which four aeration tanks 1a to 1d are arranged in series, and a drain introduction pipe 3 for injecting waste water A into the aeration tank 1a which is one end thereof is attached. . In such a wastewater treatment tank, the high temperature wastewater A flows into the aeration tank 1a from the drainage introduction pipe 3, sequentially overflows from the aeration tank 1a to the aeration tank 1d, and is discharged from the aeration tank 1d at the other end. It has become.

  Also in the apparatus shown in FIG. 2, as the cooling means, the aeration tank 1 c which is substantially in the middle of the waste water treatment tank 1, the cooling water introduction pipe 4 similar to the apparatus shown in FIG. The solid-liquid separation part 2 and the sludge return pump 6 similar to the apparatus shown in FIG. 1 are provided. Also in FIG. 2, although not shown, the cooling water introduction pipe 4 is provided with a valve for stopping the supply of the cooling water B as a cooling stopping means. In addition, air supply pipes 7a to 7d similar to the apparatus shown in FIG. 1 described above are provided at the bottoms of the aeration tanks 1a to 1d, respectively. It is the same as that of the apparatus shown in FIG. 1 also about the point provided with the waste_water | drain introduction pipe | tube 3 for flowing in the waste_water | drain A and the treated-water discharge pipe | tube 5 for discharging the treated water C.

  Further, the apparatus shown in FIG. 2 circulates the agitator 8 for agitating the sludge contained in the aeration tank 1a and the waste water (treated water) in the aeration tank 1b to the aeration tank 1a again as necessary. A treated water circulation pump 9 is provided.

  In the microorganism acclimatization apparatus and the waste water treatment apparatus of the present invention, the waste water treatment tank is divided into one tank as shown in FIG. 1 by a partition plate and one flow path from one end to the other end, or FIG. In addition to the form that consists of a plurality of tanks arranged in series as shown in FIG. 1 and that overflows sequentially from one tank to the other tank, for example, a straight flow path from one end of the tank to the other end There is no particular limitation as long as high-temperature wastewater flows from one end and treated water is discharged from the other end, such as the formed form. Further, as the cooling means, in addition to the means for injecting the cooling water B as shown in FIGS. 1 and 2, for example, a means for indirectly cooling with a heat exchanger or the like may be employed.

Next, the microorganism acclimatization method of the present invention will be described taking the case of using the apparatus shown in FIG. 1 or FIG. 2 as an example.
In the apparatus shown in FIG. 1 or FIG. 2, the high temperature waste water A flows from the drain introduction pipe 3 into one end of the waste water treatment tank 1 (one end of the aeration tank 1 or the aeration tank 1a). The inflow of the high temperature drainage A may be a batch method in which the drainage A is passed intermittently or may be a continuous method in which the drainage A is continuously passed. Inflowed waste water A flows from the aeration tank 1a to the aeration tank 1d in the apparatus of FIG. 2 by flowing to the other end of the aeration tank 1 through the flow path partitioned by the partition plate 10 in the apparatus of FIG. By sequentially overflowing, it is discharged from the other end (the other end of the aeration tank 1 or the aeration tank 1d). At this time, the wastewater treatment tank 1 contains sludge containing microorganisms, and normally supplies air necessary for the microorganisms to aerobically decompose organic matter in the wastewater A from the air supply pipe 7. To do. Furthermore, in the case of the apparatus provided with the stirring device 8 as shown in FIG. 2, the inside of the tank may be stirred.

  In this process, the high-temperature waste water A is cooled by the cooling means described above, that is, the cooling water B injection from the cooling water introduction pipe 4 to form a high-temperature drain region and a medium-temperature drain region in the waste water treatment tank 1. At this time, the high-temperature drainage area and the intermediate-temperature drainage area are formed along the flow direction of the high-temperature drainage A, that is, the high-temperature drainage area on the upstream side and the intermediate-temperature drainage area on the downstream side. .

  Then, the sludge is circulated between the high temperature drainage area and the intermediate temperature drainage area by the sludge circulation means described above. That is, from the wastewater discharged from the other end of the wastewater treatment tank 1 (the other end of the aeration tank 1 or the aeration tank 1d) by the solid-liquid separation unit 2 (treated water when the contained organic matter is decomposed). The sludge is settled and separated, and the separated sludge is returned as sludge D and returned to one end of the wastewater treatment tank 1 (one end of the aeration tank 1 or the aeration tank 1a) by the sludge return pump 6. At this time, the waste water after the sludge is settled and separated by the solid-liquid separation unit 2 (treated water when the contained organic matter is decomposed) is discharged from the treated water discharge pipe 5.

  The time per time that sludge passes through the high-temperature drainage area and the medium-temperature drainage area (that is, the time per sludge held in the high-temperature drainage area or the medium-temperature drainage area) is not particularly limited. It is preferably 1 hour to 3 days, and more preferably 1 hour to 24 hours. If the time for holding in the high temperature drainage area is less than 1 hour, or if the time for holding in the medium temperature drainage area exceeds 3 days, it is difficult to obtain the acclimatization effect of microorganisms to the high temperature environment, while the time for holding in the high temperature drainage area If it exceeds 3 days, there is a possibility that the processing activity of the microorganisms will decrease.

Further, the period for acclimatizing the sludge (the number of days during which the sludge circulates in the high-temperature drainage area and the medium-temperature drainage area) is not particularly limited, but is usually preferably 0.5 to 60 days, more preferably 1 to 30 days. It is good to do.
In addition, about the temperature of the high temperature waste_water | drain A which flows in, the temperature of the said high temperature waste_water | drain area | region formed with the cooling means and the said medium temperature waste_water | drain area, the temperature difference, etc. are as having described in description of the microorganisms acclimatization apparatus.

Next, the drainage treatment of the present invention will be described taking the case of using the apparatus shown in FIG. 1 or FIG. 2 as an example.
First, in the apparatus shown in FIG. 1 or FIG. 2, a microorganism habituation process is performed in which microorganisms are acclimated according to the microorganism acclimation method of the present invention described above.

  Thereafter, while continuing the inflow of the high temperature waste water A, the waste water treatment tank 1 is continued by the cooling stop means (the valve for stopping the supply of the cooling water B provided in the cooling water introduction pipe 4) in the apparatus shown in FIG. The cooling inside is stopped, and the decomposition treatment step of treating the high temperature wastewater A with the sludge containing the microorganisms conditioned in the microorganism habituation step is performed. Specifically, when the injection of the cooling water B is stopped by closing the valve for stopping the supply of the cooling water B provided in the cooling water introduction pipe 4, the intermediate temperature drainage area formed in the microorganism acclimatization process is continuously flowed in. The high temperature drainage A raises the temperature to the same temperature as the high temperature drainage area, so the high temperature drainage A is treated in this state, and the sludge is settled and separated in the solid-liquid separation unit 2 and then treated water C as a treated water discharge pipe 5. To discharge from. In other words, in the present invention, when acclimatizing microorganisms, there exist two temperature regions, a high temperature drainage region and a medium temperature drainage region, and the sludge is circulated in both temperature regions. When the wastewater is treated, the temperature of the intermediate temperature drainage area is returned to a temperature equivalent to that of the high temperature drainage area, and the entire area in the wastewater treatment tank is set as the high temperature drainage area to decompose organic matter in a high temperature environment. In addition, when processing the high temperature waste water A, a batch method may be used in which the waste water A is intermittently passed and biologically processed, or biological water while the waste water A is continuously passed. It may be a continuous process.

  During the period of acclimatization of the microorganism and / or the wastewater treatment, the pH in the wastewater treatment tank 1 is not particularly limited as long as the microorganism can grow, but is usually in the range of 6 to 10, preferably 6 to 6. A range of 9 is preferable. When the pH in the wastewater treatment tank 1 is out of the above range, an alkali (for example, sodium hydroxide, sodium carbonate, etc.) or an acid (for example, sulfuric acid, etc.) is appropriately added to adjust the pH within the above range. It may be adjusted so that

  In the waste water treatment method of the present invention, the high temperature waste water A is treated in the decomposition treatment step, that is, the treatment discharged from the other end of the waste water treatment tank 1 (the other end of the aeration tank 1 or the aeration tank 1d). It is also preferable to include a coagulation precipitation step of adding a coagulant to water. Thereby, it can prevent that the water quality in the waste water treatment tank 1 deteriorates with the component derived from the sludge which floated. In addition, although an excess sludge may increase by adding a flocculant, the production | generation of an excess sludge can be suppressed by performing wastewater treatment at high temperature like this invention.

In the coagulation sedimentation step, the timing for adding the coagulant is not particularly limited, and the treated water discharged from the other end of the waste water treatment tank 1 (the other end of the aeration tank 1 or the aeration tank 1d) is supplied to the solid-liquid separation unit 2. The feed sludge may be added after sedimentation or may be added before the sludge is settled and separated in the solid-liquid separator 2, but in the former case, the sludge after further agglomeration is then added. The latter is preferred because it requires a separation step.
The flocculant that can be used in the flocculation and precipitation step is not particularly limited. For example, in addition to inorganic flocculants such as sulfate band (aluminum sulfate), polyaluminum chloride, and ferric chloride, cationic, anionic or Amphoteric polymer flocculants and the like can be used. The amount of the flocculant added is not particularly limited as long as it is an amount capable of aggregating sludge. For example, 0.01 to 0.5 parts by mass of the inorganic flocculant with respect to 100 parts by mass of the treated water, the polymer In a system flocculant, it is good to set it as 0.1-1 mass part.

  As described above, in the wastewater treatment method of the present invention, the microorganism is acclimatized so that the organic matter can be efficiently decomposed even in a high-temperature environment in the microorganism acclimatization step, and the wastewater treatment tank is used using the acclimatized microorganism. The entire area inside is set as a high temperature drainage area, and the organic matter in the high temperature drainage A is aerobically decomposed by microorganisms in a high temperature environment. Thereby, a microorganism can be acclimatized stably, without reducing the processing activity of a microorganism.

  In the present invention, it is not clear why the microorganisms can be stably habituated without reducing the treatment activity of the microorganisms by circulating the microorganisms between the high temperature drainage area and the intermediate temperature drainage area. I think so. That is, a microorganism is an aggregate of various microorganisms, a microorganism having an intermediate growth environment as an optimal growth environment (hereinafter referred to as a medium temperature bacterium) and a microorganism having a high temperature environment as an optimal growth environment (hereinafter referred to as a high temperature bacteria). ) Symbiotic with mesophilic bacteria in the medium temperature environment, and thermophilic bacteria in the high temperature environment. Since mesophilic bacteria are resistant to high temperature environments for a short period of time, exposure to high temperature environments for a short period of time and quick return to the medium temperature environment will prevent the mesophilic bacteria from dying or declining so much. Maintained. On the other hand, thermophilic bacteria grow or activate when exposed to a high temperature environment even for a very short time. By repeatedly exposing to a medium temperature environment and a high temperature environment, it is presumed that thermophilic bacteria gradually dominate without significantly changing the treatment activity.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by this Example.

(Reference Example 1)
Using the processing apparatus shown in FIG. 2 in which four aeration tanks 1a to 1d having an internal volume of 18L, 35L, 9L and 16L are arranged in series (however, in Reference Example 1, the cooling water introduction pipe 4 was not used). The organic wastewater discharged from the chemical factory was treated. That is, activated sludge (MLSS concentration of about 8000 mg / L) obtained at a chemical factory is charged into the aeration tank 1a of the apparatus, and then the inside of the aeration tank 1a is agitated by the agitator 8, and the air supply pipes 7a to 7d are used. While supplying air, organic waste water whose temperature was adjusted to about 32 ° C. in advance was introduced from the waste water introduction pipe 3 at a flow rate of about 100 mL / min, and was sequentially overflowed from the aeration tank 1a to the aeration tank 1d. And while the waste water A overflows sequentially from the aeration tank 1a to the aeration tank 1d, the organic matter in the waste water A is aerobically decomposed in each of the aeration tanks 1a to 1d. After sedimentation and separation, the COD (chemical oxygen demand) concentration of the treated water C discharged from the treated water discharge pipe 5 was measured, and the results are shown in FIG.
During the treatment period, the water temperature in the aeration tanks 1a to 1d was maintained at about 32 ° C. Further, the sludge settled and separated in the solid-liquid separation unit 2 is sent to the aeration tank 1a at a rate of about 90 mL / min by the sludge return pump 6, and the MLSS concentration in the aeration tanks 1a to 1d is appropriately extracted by removing the sludge. Was adjusted to be in the range of about 6000 to 10000 mg / L. In addition, the aerobic treated water circulation pump 9 circulated waste water (treated water) in the aerated tank 1b to the aerated tank 1a at about 500 mL / min.

(Comparative example)
Using the same treatment device and activated sludge as the treatment device used in Reference Example 1 (however, the cooling water introduction pipe 4 was not used in Reference Example 1), proceeded simultaneously with the treatment of Reference Example 1, In the same manner as in Reference Example 1, the same organic wastewater treated in 1 (organic wastewater whose temperature was adjusted to about 32 ° C. in advance) was treated.
Prior to the treatment, the temperature in the aeration tanks 1a to 1d is increased by about 2 ° C. every 4 to 7 days until the water temperature in the aeration tanks 1a to 1d reaches about 42 ° C. (the temperature of the 1b tank in FIG. 3 is increased). Reference), by circulating the sludge together with the drainage A, the microorganisms in the sludge were habituated. Subsequently, the waste water A was decomposed.
The COD concentration of the treated water C discharged from the treated water discharge pipe 5 was measured during the entire treatment period including the acclimatization period of microorganisms. The results are shown in FIG. 3 together with the COD concentration of the waste water A introduced into the apparatus and the COD concentration of the treated water C in Reference Example 1.
Although the decrease in the COD removal rate was observed after the water temperature in the aeration tanks 1a to 1d reached about 42 ° C. and then gradually recovered, the treated water COD concentration in this comparative example was the same as the treated water COD concentration in Reference Example 1. When compared, the maximum deterioration was 90 mg / L, and the fluctuation was large (see the part circled in FIG. 3).

(Reference Example 2)
Using the treatment equipment and activated sludge used in Reference Example 1, treatment of organic wastewater discharged from the chemical factory (organic wastewater whose temperature was adjusted to about 32 ° C in advance) by the same operation as Reference Example 1. I did it. In this treatment, the COD concentration of the treated water C discharged from the treated water discharge pipe 5 was measured, and the result is shown in FIG.
(Example)
Using the same processing apparatus and activated sludge as the processing apparatus used in Reference Example 1 (however, the cooling water introduction pipe 4 was not used in Reference Example 1), approximately 38 The organic waste water at ℃ was treated.
Prior to the treatment, the aerobic treated water circulation pump 9 was stopped in the treatment apparatus to acclimate the microorganisms in the sludge. Specifically, for acclimatization of microorganisms, the water temperature in the aeration tanks 1a to 1d is temporarily maintained at about 38 ° C. using heating means and / or cooling means (not shown), and then about 43 ° C. waste water is introduced. By setting the water temperature in the aeration tank 1a and the aeration tank 1b to about 42 ° C. and simultaneously injecting the cooling water B from the cooling water introduction pipe 4 into the aeration tank 1c, the water temperature in the aeration tank 1c and the aeration tank 1d is 38 ° C. In this state, the sludge was circulated together with the drainage water A while maintaining this state (see the temperature of the 1b tank and the temperature of the 1d tank in FIG. 4). Thereafter, the injection of the cooling water B was stopped, and the water temperature in the aeration tank 1c and the aeration tank 1d was raised to about 42 ° C. (see the temperature of the 1d tank in FIG. 4), and the waste water A was subsequently decomposed. .
The COD concentration of the treated water C discharged from the treated water discharge pipe 5 was measured during the entire treatment period including the acclimatization period of microorganisms. The results are shown in FIG. 4 together with the COD concentration of the waste water A introduced into the apparatus and the COD concentration of the treated water C in Reference Example 2.
While acclimatizing microorganisms with the aeration tank 1a and the aeration tank 1b being about 42 ° C. and the aeration tank 1c and the aeration tank 1d being 38 ° C., the treated water COD concentration in this example is equal to the treated water COD concentration in Reference Example 2. In comparison, it was only deteriorated by about 35 mg / L at most (refer to the circled portion in FIG. 4), and the COD removal rate was always at a high level and fluctuated during the acclimation period of the microorganism and the subsequent wastewater treatment period. It was small.

(A) is a schematic diagram which shows one Embodiment of the microorganisms acclimatization apparatus and waste water treatment apparatus concerning this invention, (b) is the schematic diagram which planarly viewed the apparatus of said (a). It is a schematic diagram which shows other embodiment of the microorganisms acclimatization apparatus and waste water treatment apparatus concerning this invention. It is a graph which shows the result of a comparative example. It is a graph which shows the result of an Example.

Explanation of symbols

1 Wastewater treatment tank (aeration tank)
2 Solid-liquid separation section 3 Drainage introduction pipe 4 Cooling water introduction pipe 5 Treated water discharge pipe 6 Sludge return pump 7 Air supply pipe 8 Stirrer 9 Aerobic treated water circulation pump A Drain B Cooling water C Treated water D Return sludge

Claims (3)

A device for acclimatizing microorganisms to high temperature wastewater and aerobically decomposing organic matter in the high temperature wastewater by the microorganisms,
A wastewater treatment tank in which high temperature wastewater flows from one end and treated water is discharged from the other end,
A cooling means attached to the wastewater treatment tank, for cooling the high temperature wastewater and forming a high temperature drainage area and a medium temperature drainage area in the wastewater treatment tank along the flow direction of the high temperature wastewater;
A sludge circulation means for circulating sludge containing microorganisms between a high temperature drainage area and a medium temperature drainage area;
Also have a means for stopping the cooling of the waste water treatment tank after the addition microorganisms are acclimatized to the hot waste water,
The temperature of the high temperature drainage and the high temperature drainage zone is more than 40 ° C and less than 45 ° C, and the medium temperature
A wastewater treatment apparatus characterized in that the temperature of the drainage area is 40 ° C or lower . A wastewater treatment method for aerobically decomposing organic matter in high temperature wastewater by microorganisms,
In the process of injecting high temperature waste water from one end of the waste water treatment tank and discharging from the other end, the high temperature waste water exceeding 40 ° C. and less than 45 ° C. is cooled to exceed 40 ° C. and less than 45 ° C. in the waste water treatment tank A microorganism that acclimates microorganisms by a microorganism acclimatization method that forms a high temperature drainage area and a medium temperature drainage area that is 40 ° C. or less along the flow direction of the high temperature drainage, and circulates sludge between the high temperature drainage area and the intermediate temperature drainage area. The acclimatization process,
A wastewater treatment method comprising: after the microorganism habituation step, cooling in the wastewater treatment tank is stopped, and a high temperature wastewater is treated with sludge containing microorganisms habituated in the microorganism habituation step.   The drainage according to claim 2, wherein the time per one time that the sludge passes through the high temperature drainage area or the medium temperature drainage area is 1 hour to 3 days, and the period of acclimatization of the sludge is 0.5 to 60 days. Processing method.

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