JP6676417B2 - Organic wastewater biological treatment apparatus and biological treatment method - Google Patents

Description

  The present invention relates to a biological treatment apparatus and a biological treatment method for organic wastewater, which improves the treatment efficiency of microorganisms and reduces the amount of excess sludge generated by using predation of microorganisms. The present invention relates to a biological treatment apparatus and a biological treatment method.

In biological treatment of organic wastewater, the activated sludge method is widely used. The activated sludge method is widely used in sewage treatment and industrial wastewater treatment equipment because of its excellent quality of treated water and easy maintenance. However, the BOD volume load in the activated sludge method is about 0.3 to 0.8 kg-BOD / m ³ / day, and a large site area is required. In addition, since 40 to 50% of the decomposed organic matter is used for cell synthesis, the amount of excess sludge generated is a problem.

  In addition, in biological treatment of organic wastewater, there is a fluidized bed method using a carrier in order to maintain a high concentration of microorganisms in a treatment tank. This method can increase the organic substance load per processing tank volume as compared with a general activated sludge method, and is excellent in processing efficiency. Therefore, the processing tank volume can be reduced.

  In Patent Literature 1, organic wastewater is treated with bacteria in a first treatment tank, and organic matter contained in the wastewater is oxidatively decomposed and converted into non-aggregated bacteria including dispersed bacteria. It is disclosed that the amount of surplus sludge is reduced by predation and removal by sticky protozoa in the second treatment tank. However, in the second treatment tank, it is necessary to generate flocs capable of solid-liquid separation, and in order to proliferate protozoa with a low growth rate, the treatment tank must be provided in order to increase the sludge residence time in the second treatment tank. Need to be bigger.

Further, a high-load treatment in which a carrier is added to a treatment tank is known. For example, in Patent Document 2, a carrier having a volume occupied by a carrier of 5 to 30% is charged into a first treatment tank, and treated at a BOD volume load of 2 to 100 kg / m ³ / day, whereby microorganisms grow and are retained on the carrier. Thus, high-load processing can be performed. Further, the treated water is sent to a second treatment tank charged with a carrier of 20 to 90%, and the BOD is decomposed at a BOD volume load of 0.1 to 2 kg / m ³ / day, and the activated sludge is flocculated. Solid-liquid separation is performed in a liquid separation tank.

  This method lowers the carrier filling rate of the first treatment tank and raises the carrier filling rate of the second treatment tank, thereby increasing the BOD volume load and performing stable BOD removal while reducing the reaction vessel volume. Form sludge with good solid-liquid separation properties. However, the carrier to be charged is preferably a granular and flowable one. When each vessel is filled with the carrier, it is necessary to provide a carrier separation means such as a screen for separating the carrier and taking out the mixed liquid. In addition, power for flowing the granular carrier is required, which increases the cost.

  Further, in Patent Document 3, the priority of filamentous bacteria is suppressed by high load treatment of the BOD sludge load of the first treatment tank of 2 to 40 kg-BOD / kg-VSS / day, and soluble BOD is removed by 50% or more. It is treated water having a soluble BOD concentration of 50 to 10000 mg / L. Further, this treated water is sent to a second treatment tank charged with a carrier of 20 to 90%, and treated with a BOD sludge load of 0.01 to 0.5 kg-BOD / kg-VSS / day to decompose the BOD. At the same time, the activated sludge is flocculated, and good treated water having a low organic matter concentration and a low SS concentration can be obtained.

  This method prevents bulking due to the priority of filamentous bacteria by increasing the load on the first treatment tank, and flocculates the dispersible sludge sent from the first treatment tank in the second treatment tank containing the carrier. Thus, sludge having good solid-liquid separation properties can be formed. However, since this method has activated sludge and activated sludge into which a carrier has been added, the amount of air required for performing treatment under a high load increases. The second reaction tank is charged with a carrier, and requires air and power for flowing the carrier.

JP-A-55-20649 JP-A-2000-42584 JP 2001-314885 A JP 2013-208560 A JP 2013-141640 A

Written by Isao Soumiya, "Easy Water Treatment", (Issue) Isao Soumiya, (Printing) Tanaka Print Co., Ltd.

  The problem to be solved by the present invention, in view of the above-mentioned problems, is to reduce the amount of air for aerobic biological treatment, and to efficiently remove organic matter with a high load while significantly reducing the amount of generated sludge. It is an object of the present invention to provide a possible organic wastewater biological treatment device and biological treatment method.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the biological treatment apparatus and the biological treatment method of the organic wastewater of this invention have the following characteristics.
(1) A plurality of biological treatment tanks are arranged in multiple stages, and in each of the biological treatment tanks, an inflow section into which organic wastewater or treated water treated in the preceding biological treatment tank flows, and the biological treatment tank And a discharge section for discharging the treated water treated therein is provided.A sedimentation basin is provided at a subsequent stage of the biological treatment tank at the final stage, and the treated water treated at the biological treatment tank at the final stage flows thereinto to be settled. In a biological treatment apparatus for organic wastewater that discharges treated water, a fixed contact carrier is disposed in all of the biological treatment tanks, and a diffuser is provided below the position where the fixed contact carrier is disposed. The inflow portion is disposed above the position where the fixed contact carrier is disposed, and the discharge portion is disposed below the position where the fixed contact carrier is disposed. The first biological treatment tank into which wastewater flows, and the second biological treatment tank into which treated water from the preceding Divided into two biological treatment tanks, the treated water treated in the first biological treatment tank is passed through the second biological treatment tank , furthermore, the organic matter concentration of the organic wastewater flowing into the first biological treatment tank An inflow rate adjustment apparatus comprising an organic substance load measuring device for measuring a flow rate, and adjusting an inflow amount of organic wastewater flowing into each biological treatment tank constituting the first biological treatment tank based on a measurement value of the organic substance load measurement apparatus. comprising means, flow Iriryou adjusting means based on the measurement result of the organic load measuring instrument, 3~12kg / m organics inflow load flowing into the biological treatment tank which constitutes the said first biological treatment tank with COD _Cr ^The flow rate is adjusted so as to be ³ / day .

(2) In the biological treatment apparatus of an organic waste water according to the above (1), the flow Iriryou adjusting means based on the measurement result of the organic load measuring device, organic loading for all organism processing tank with COD _Cr and adjusting the flow Iriryou so that 0.75~3kg ^/ m 3 ^/ da y.

( 3 ) In a biological treatment method for organic wastewater, in which organic wastewater is treated using a biological treatment apparatus in which a plurality of biological treatment tanks are arranged in multiple stages, all of the biological treatment tanks include a fixed contact carrier; Organic wastewater or treated water treated in the biological treatment tank in the preceding stage is introduced from above the position of the fixed contact carrier, and the treatment is performed while supplying air in the biological treatment tank. A biological treatment step of discharging treated water from the lower side of the disposition position, wherein the biological treatment step is a first biological treatment step of introducing and treating organic wastewater, and the organic wastewater is introduced. The second biological treatment step is divided into a second biological treatment step of introducing and treating the treated water from the previous stage, and treating the treated water treated in the first biological treatment step in the second biological treatment step. Settling process to settle the treated water treated in For example, in said first biological treatment process, organic matter concentration and the flow rate of organic wastewater entering the organism processing tank was measured, both for adjusting the flow rate of the organic waste water, adjusting the flow rate of organic wastewater Is characterized in that the organic matter inflow into each biological treatment tank constituting the first biological treatment step is performed so that COD _Cr is ³ to 12 kg / m ³ / day in COD _Cr .

( 4 ) In the biological treatment method for organic wastewater according to the above ( 3 ), the flow rate of the organic wastewater is adjusted by adjusting the organic substance load to all the biological treatment tanks to 0.75 to 3 kg / m in COD _Cr. and performing such a ³ / da y.

  In the biological treatment apparatus and the biological treatment method for organic wastewater of the present invention, by providing a fixed contact carrier in all biological treatment tanks, it is possible to reduce the amount of air for aerobic biological treatment. In addition, an organic matter load measuring device is provided at the inflow portion of the organic wastewater, and by adjusting the inflow amount of the organic wastewater, an appropriate organic matter load corresponding to the allowable organic matter load of each biological treatment tank constituting the first biological treatment tank is provided. The organic matter concentration can be maintained in the biological treatment tank. As a result, the capacity of the treatment tank can be reduced, the organic matter can be efficiently removed, and the amount of generated sludge can be reduced.

It is a figure showing the outline of the biological treatment device of the present invention. It is a figure which shows the outline of the biological treatment apparatus of this invention, Comprising: It is a figure which shows the example which comprises a 1st biological treatment tank with two tanks. FIG. 1 is a diagram illustrating an outline of an experimental apparatus according to a first embodiment of the present invention. It is a figure which shows the experimental device outline | summary of the comparative example 1-1 which concerns on this invention. It is a figure showing the experimental device outline of comparative example 1-2 concerning the present invention. It is a figure showing the outline of the experimental device of comparative example 1-3 concerning the present invention. It is a figure showing the outline of the experimental device of Example 2 concerning the present invention. It is a figure showing the outline of the experimental device of Example 5 concerning the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION The organic wastewater treatment apparatus and treatment method of the present invention will be described in detail below.
The first biological treatment tank used in the present invention is a treatment tank into which organic wastewater flows, and the second biological treatment tank is a treatment tank that flows treated water from the first biological treatment tank and passes it to the sedimentation tank. is there.

FIG. 1 shows an example of the biological treatment apparatus of the present invention, and the present invention is not limited to the embodiment shown here. It comprises a first biological treatment tank into which organic wastewater flows and a second biological treatment tank into which treated water from the first biological treatment tank flows, and an air diffuser is provided below the biological treatment tank. Further, below the biological treatment tank (downstream side), there is an inlet of a discharge pipe for draining treated water, and a fixed contact carrier is installed in the biological treatment tank.
In addition, the fixed contact carrier of the present invention includes not only those fixedly disposed in the biological treatment tank but also those configured such that the contact carriers are dense and the contact carriers do not easily flow.

  The shape of the fixed contact carrier to be installed in the first biological treatment tank and the second biological treatment tank is, as shown in Non-Patent Literature, a generally usable corrugated plate, honeycomb tube, bottle, tube, net, ball A carrier having a shape such as a shape or a sea urchin is preferable. By providing a contact carrier in the first biological treatment tank and the second biological treatment tank, microorganisms adhere to the contact carrier, and microorganisms corresponding to the load of each tank grow, thereby efficiently treating the organic matter in the tank. Becomes possible.

The first biological treatment tank is a treatment tank into which the organic wastewater flows, and it is preferable that the organic wastewater flows at a COD _Cr volume load of ^{3 to 12} kg / m ³ / day, preferably 6 to 10 kg / m ³ / day. In addition, it is preferable that the organic wastewater is introduced at a COD _Cr volume load of 0.75 to ³ kg / m ³ / day, preferably 1.1 to 2.5 kg / m ³ / day per tank.

It is preferable that the organic matter removal rate at the outlet of the first biological treatment tank is 60 to 95%, preferably 70 to 85%.
Further, the amount of air in the first biological treatment tank is preferably such that oxygen is sufficiently distributed to the microorganisms attached to the carrier, and may be 0.05 to 0.2 m ³ / m ² / min.

  By causing the organic wastewater to flow into the first biological treatment tank under the above-described conditions, the disperse bacteria multiply and the treated water in which the disperse bacteria predominate can be obtained.

  The second biological treatment tank is a treatment tank into which treated water from the first biological treatment tank flows, and is preferably one or more stages. The organic matter removal rate at the outlet of the second biological treatment tank a is preferably set to be 60% or more, and it is preferable that the organic matter removal rate increases toward the later stage. It is preferable that the amount of air in the second biological treatment tank is reduced in a later stage, and the amount of air in the second biological treatment tank a may be the same as that of the first biological treatment tank. Since the dispersed bacteria grown in the first biological treatment tank are predatory by the protozoa and metazoa in the second biological treatment tank in stages, the SS amount of the treated water in the second biological treatment tank is reduced.

FIG. 2 has two or more biological treatment tanks constituting a first biological treatment tank into which organic wastewater flows, and a second biological treatment tank into which treated water from the first biological treatment tank flows has two biological treatment tanks. Have more than one step. An aeration device is provided below the biological treatment tank, a treated water discharge pipe is provided downstream of the biological treatment tank, and a fixed contact carrier is provided in the biological treatment tank. For the organic wastewater, the organic matter concentration is measured by an organic matter measuring device, and the COD _Cr volume load per biological treatment tank constituting the first biological treatment tank is ³ to 12 kg / m ³ / day, preferably according to the organic matter concentration. Is introduced so as to be 6 to 10 kg / m ³ / day.

  In FIG. 2, the two biological treatment tanks constituting the first biological treatment tank are arranged in series, but they may be arranged in parallel. In addition, not only the treated water treated in the first biological treatment tank is supplied to one of the first biological treatment tanks constituting the second biological treatment tank, but also the first biological treatment tank is composed of a plurality of biological treatment tanks. It is also possible.

The organic matter load measuring device M indicates a device and a measuring means capable of measuring the organic matter concentration of the organic matter wastewater, and preferably measures the COD _Cr concentration. A typical BOD of an organic substance concentration requires 5 days for measurement, and is not suitable for quickly determining an organic substance concentration. Therefore, the COD _Cr concentration that can quickly determine the organic substance concentration is used. COD _Cr was converted as 1.5 times BOD.

  It is preferable that the organic matter removal rate at the outlet of the first biological treatment tank is 30 to 95%, preferably 45 to 85%. By causing the organic wastewater to flow into the first biological treatment tank under the above-described conditions, the dispersed bacteria proliferate, and it is possible to obtain treated water in which the dispersed bacteria that are not the conventional flocs are dominant.

  The second biological treatment tank is a treatment tank into which the treated water from the first biological treatment tank flows, and the organic matter removal at the outlet of the second biological treatment tank a is preferably 60% or more. Preferably, Since the dispersed bacteria grown in the first biological treatment tank are predatory by the protozoa and metazoa in the second biological treatment tank in stages, the SS amount of the treated water in the second biological treatment tank is reduced.

The treated water containing the dispersed bacteria grown in the first biological treatment tank flows into the second biological treatment tank, and sludge is reduced by feeding the dispersed bacteria grown in the first biological treatment tank.
Sludge conversion rate is used to evaluate sludge generation and is defined as follows.

  Four biological treatment tanks were arranged in series, organic wastewater from a food factory was allowed to flow into the first biological treatment tank, and an air diffuser was installed at the bottom of the treatment tank to perform the treatment. As shown in FIG. 3, Example 1 was an experiment in which an immobilized contact carrier was provided in all biological treatment tanks for treatment.

As a comparative example of Example 1, an experiment in which a fixed contact carrier was provided in the first biological treatment tank and treatment was performed without providing the contact carriers in the second biological treatment tanks a to c was set as Comparative Example 1-1. FIG. 4 shows an apparatus diagram.
An experiment in which fixed contact carriers were provided in the second biological treatment tanks a to c without the contact carriers in the first biological treatment tank and the treatment was performed was set as Comparative Example 1-2. FIG. 5 shows an apparatus diagram.
As a comparative example of Example 1, an experiment in which treatment was performed by the activated sludge method was taken as Comparative Example 1-3. FIG. 6 shows an apparatus diagram.

Tables 1 and 2 show the outline of the experimental apparatus and the experimental conditions. The tank capacity was 10 m ³ , the COD _Cr concentration of the organic wastewater was adjusted to 1800 mg / L, the inflow was adjusted to 8.3 m ³ / day, and the COD _Cr volume load of the first biological treatment tank was adjusted to 6 kg / m ³ / day. The amount of air in Example 1, 0.3 m ³ / min per total bath each experiment, 0.45 m ³ / min in Comparative Example 1-1, Comparative Example 1-2 0.50 m ³ / min, Comparative Example In 1-3, it was set to 0.65 m ³ / min.

Table 3 shows the experimental results of this example. When treated under the conditions of Example 1, the SS at the fourth tank outlet was 73 mg / L, and the SS and COD _Cr of the treated water were 28 mg / L and 150 mg / L, and the treatment was satisfactory. The sludge conversion rate was 0.04 kg-SS / kg-COD _Cr . The DO in the tank was 6 to 8 mg / L.

When treated under the conditions of Comparative Example 1-1, the SS at the fourth tank outlet was 200 mg / L, and the SS and COD _Cr of the treated water were 42 mg / L and 330 mg / L. The sludge conversion rate was 0.10 kg-SS / kg-COD _Cr . The treated water that became the dispersed bacteria in the first biological treatment tank flowed into the second biological treatment tank where no contact carrier was installed, and flocs of sludge were formed. Since the formed floc flowed to the subsequent stage as it was, the SS at the outlet of the fourth tank increased. Further, the COD _{Cr of the} treated water was high, and the treatment was not sufficiently performed.

When treated under the conditions of Comparative Example 1-2, the SS at the fourth tank outlet was 170 mg / L, and the SS and COD _Cr of the treated water were 46 mg / L and 190 mg / L. The sludge conversion rate was 0.08 kg-SS / kg-COD _Cr . Flocs of sludge were formed in the first biological treatment tank where the contact carrier was not installed, and the flocs flowed into the second biological treatment tank where the contact carrier was installed. Among the flocs formed in the first biological treatment tank, some flocs were not captured by the contact carrier, and the SS flowed out due to those flocs flowing out. In Comparative Example 1-2, since there was a contact carrier at the subsequent stage, the SS concentration at the fourth tank outlet was lower and the quality of the treated water was lower than in Comparative Example 1-1.

The SS and COD _Cr of the treated water when treated under the conditions of Comparative Example 1-3 were 76 mg / L and 110 mg / L. The sludge conversion rate was 0.33 kg-SS / kg-COD _Cr . The COD _Cr of the treated water was lower than in Example 1, but the SS and the sludge conversion rate were higher than those in Example 1, Comparative Examples 1-1 and 1-2. The DO in the tank was 2 to 6 mg / L. The amount of air per tank in Example 1 was 0.3 m ³ / min, whereas the amount of air in Comparative Example 1-3 was 0.65 m ³ / min, requiring a large amount of air.

An experiment when the load was reduced is shown in Comparative Example 2, and the conditions and results of Example 1 are also described below.
In Example 1, a test was conducted using the biological treatment apparatus shown in FIG. 3 with all biological treatment tanks provided with fixed contact carriers. Table 4 shows the outline of the experimental apparatus and the experimental conditions.

The tank capacity was 10 m ^3, and in Example 1, the COD _Cr concentration of the organic wastewater was 1800 mg / L, the inflow was 8.3 m ³ / day, and the COD _Cr volume load of the first biological treatment tank was 6 kg / m ³ / day. Was adjusted. In addition, the amount of air per tank in each experiment was 0.3 m ³ / min. As a comparative example of Example 1, an experiment was performed in which the COD _Cr volume load of the first biological treatment tank was 2.8 kg / m ³ / day. Comparative Example 2 was prepared by adjusting the COD _Cr concentration of the organic wastewater to 1800 mg / L and adjusting the inflow amount to 3.9 m ³ / day.

Table 5 shows the experimental results of this example. When treated under the conditions of Example 1, the SS at the fourth tank outlet was 73 mg / L, and the SS and COD _Cr of the treated water were 28 mg / L and 150 mg / L, and the treatment was satisfactory. The sludge conversion rate was 0.04 kg-SS / kg-COD _Cr .

When treated under the conditions of Comparative Example 2, the SS at the fourth tank outlet was 140 mg / L, and the SS and COD _Cr of the treated water were 72 mg / L and 380 mg / L. The sludge conversion rate was 0.11 kg-SS / kg-COD _Cr . Since the sludge was separated from the contact carrier and the sludge was disintegrated, the SS at the outlet of the fourth tank was high, and the treated water deteriorated.

In Example 2, four biological treatment tanks were arranged in series, and organic wastewater was flowed into two tanks of the first biological treatment tanks a and b, and a treatment was performed by installing an air diffuser at the lower part of the treatment tank. As shown in FIG. 7, a test was conducted by providing a fixed contact carrier in all biological treatment tanks. An organic substance measuring device was installed in the inflow line of the organic waste water to measure the COD _Cr concentration, and the COD _Cr was introduced so that the volume load of COD _Cr in the first biological treatment tank a was 6.5 kg / m ³ / day. The tank capacity was 10 m ^3, and the COD _Cr concentration of the organic wastewater was 1800 mg / L. Inflow first biological treatment tank a is 9.0 m ³ / day, the first biological treatment tank b are as 8.3m ³ / day, _{COD Cr} volumetric loading has first biological treatment tank a 6.5 kg / ^{m 3} / Day and the first biological treatment tank b were adjusted to 6.0 kg / m ³ / day. The amount of air per tank was 0.3 m ³ / min. Table 6 shows the outline of the experimental apparatus and the experimental conditions.

In Comparative Example 3, the organic wastewater was allowed to flow only into the first biological treatment tank a. The tank capacity was 10 m ³ , the COD _Cr concentration of the organic wastewater was adjusted to 1800 mg / L, the inflow was 17.4 m ³ / day, and the COD _Cr volume load of the first biological treatment tank was adjusted to 12.5 kg / m ³ / day. . The amount of air per tank was 0.3 m ³ / min.

Table 7 shows the experimental results. When treated under the conditions of Comparative Example 3, the SS at the fourth tank outlet was 420 mg / L, and the SS and COD _Cr of the treated water were 72 mg / L and 480 mg / L. The sludge conversion rate was 0.20 kg-SS / kg-COD _Cr . In the first biological treatment tank a and the second biological treatment tank a, a large amount of sludge adhered to the contact carrier, and clogging in the tank was observed. Further, a large amount of dispersed bacteria was generated in the first biological treatment tank, and the dispersed bacteria that were not preyed in the second biological treatment tank a flowed out to the subsequent stage. Therefore, the SS at the outlet of the fourth tank increased, and the sludge conversion rate also increased.

In Example 2, as shown in FIG. 7, the organic wastewater was split into two first biological treatment tanks a and b and flowed. The tank capacity was 10 m ³ , the COD _Cr concentration of the organic wastewater was 1800 mg / L, the inflows of the first biological treatment tanks a and b were 9.0 m ³ / day and 8.3 m ³ / day, and the first biological treatment was performed. The COD _Cr volume loading of the tanks a and b was adjusted to 6.5 kg / m ³ / day and 6.0 kg / m ³ / day.

When treated under the conditions of Example 2, the SS at the outlet of the fourth tank was 270 mg / L, and the SS and COD _Cr of the treated water were 44 mg / L and 360 mg / L. The sludge conversion rate was 0.14 kg-SS / kg-COD _Cr . Dispersed bacteria were generated in the first biological treatment tank, and predation of the dispersed bacteria was performed in the second biological treatment tank. As compared with Comparative Example 3 in which the organic wastewater was flown only into the first biological tank a at the same inflow amount as in Example 2, there was no excessive sludge attached to the carrier, and the treatment was satisfactorily performed.

An experiment in the case where the concentration of organic wastewater is constant and the amount of inflow varies.
In the third embodiment, using the same biological treatment apparatus as in the second embodiment, organic wastewater is introduced into two tanks of the first biological treatment tanks a and b, and an air diffuser is provided at a lower portion of the treatment tank to perform treatment. went. An organic matter measuring device is installed in the inflow line of the organic wastewater to measure the COD _Cr concentration, and the COD _Cr volume load of the first biological treatment tank a is adjusted to 6.5 kg / m ³ / day, and the remaining is set. The waste water was allowed to flow into the biological treatment tank b. The tank capacity was 10 m ^3, and the COD _Cr concentration of the organic wastewater was 1800 mg / L.

Inflow is 9.0 m ³ / day in the first biological treatment tank a, and 0~8.3m ³ / day in the first biological treatment tank b, _{COD Cr} volumetric loading 6.5kg the first biological treatment tank a / m ³ / day was adjusted to 0 to 6.0 kg / m ³ / day in the first biological treatment tank b. The amount of air per tank was 0.3 m ³ / min. Table 8 shows an outline of the experimental apparatus and experimental conditions.

In Comparative Example 4, the same biological treatment apparatus as in Example 1 was used, and the organic wastewater was allowed to flow only into the first biological treatment tank a. The tank capacity is 10 m ³ , the COD _Cr concentration of the organic wastewater is 1800 mg / L, the inflow amount is 9.0 to 17.4 m ³ / day, and the COD _Cr volume load of the first biological treatment tank is 6.5 to 12.5 kg. / M ³ / day. The amount of air per tank was 0.3 m ³ / min.

Table 9 shows the experimental results. When treated under the conditions of Comparative Example 4, the SS at the outlet of the fourth tank was 280 mg / L, and the SS and COD _Cr of the treated water were 70 mg / L and 430 mg / L. The sludge conversion rate was 0.16 kg-SS / kg-COD _Cr . In the first biological treatment tank a and the second biological treatment tank a, a large amount of sludge adhered to the contact carrier, and clogging in the tank was observed. Further, a large amount of dispersed bacteria was generated in the first biological treatment tank, and the dispersed bacteria that were not preyed in the second biological treatment tank a flowed out to the subsequent stage. Therefore, the SS at the outlet of the fourth tank increased, and the sludge conversion rate also increased.

When treated under the conditions of Example 3, the SS at the fourth tank outlet was 170 mg / L, and the SS and COD _Cr of the treated water were 36 mg / L and 250 mg / L. The sludge conversion rate was 0.09 kg-SS / kg-COD _Cr . Dispersed bacteria were generated in the first biological treatment tank, and predation of the dispersed bacteria was performed in the second biological treatment tank. Compared with Comparative Example 4 in which the organic wastewater was flown only into the first biological tank a with the same volume load as in Example 3, there was no excessive sludge attached to the carrier, and the treatment was satisfactorily performed.

The experiment when the inflow of organic wastewater is constant and the concentration fluctuates is shown.
In the fourth embodiment, using the same biological treatment apparatus as in the second embodiment, organic wastewater is introduced into two tanks of the first biological treatment tanks a and b, and an air diffuser is provided at a lower portion of the treatment tank to perform treatment. went. An organic matter measuring device is installed in the inflow line of the organic wastewater to measure the COD _Cr concentration, and the COD _Cr volume load of the first biological treatment tank a is adjusted to 6.5 kg / m ³ / day, and the remaining is set. The wastewater flowed into the first biological treatment tank b.

Tank volume and 10 m ^3, _{COD Cr} concentration of the organic waste water was 1200~1800mg / L. Inflow is 9.0~13.5m ³ / day in the first biological treatment tank a, and 3.9~8.4m ³ / day in the first biological treatment tank b, _{COD Cr} volumetric loading the first biological treatment tank a in 6.5kg ^/ m 3 ^/ day, adjusted to 1.9~6.0kg ^/ m 3 ^/ day in the first biological treatment tank b. The amount of air per tank was 0.3 m ³ / min. Table 10 shows an outline of the experimental apparatus and experimental conditions.

In Comparative Example 5, using the same biological treatment apparatus as in Example 1, the organic wastewater was allowed to flow only into the first biological treatment tank a. The tank capacity was 10 m ³ , the COD _Cr concentration of the organic wastewater was 1200 to 1800 mg / L, the inflow was 17.4 m ³ / day, and the COD _Cr volume load of the first biological treatment tank was 8.4 to 12.5 kg / m. ^It was adjusted to ³ / day. The amount of air per tank was 0.3 m ³ / min.

Table 11 shows the experimental results. When treated under the conditions of Comparative Example 5, the SS at the fourth tank outlet was 350 mg / L, and the SS and COD _Cr of the treated water were 70 mg / L and 460 mg / L. The sludge conversion rate was 0.18 kg-SS / kg-COD _Cr . In the first biological treatment tank a and the second biological treatment tank a, a large amount of sludge adhered to the contact carrier, and clogging in the tank was observed. Further, a large amount of dispersed bacteria was generated in the first biological treatment tank, and the dispersed bacteria that were not preyed in the second biological treatment tank a flowed out to the subsequent stage. Therefore, the SS at the outlet of the fourth tank increased, and the sludge conversion rate also increased.

When treated under the conditions of Example 4, the SS at the outlet of the fourth tank was 180 mg / L, and the SS and COD _Cr of the treated water were 40 mg / L and 280 mg / L. The sludge conversion rate was 0.10 kg-SS / kg-COD _Cr . Dispersed bacteria were generated in the first biological treatment tank, and predation of the dispersed bacteria was performed in the second biological treatment tank. Compared with Comparative Example 5 in which the organic wastewater was flowed only into the first biological tank a at the same inflow amount as in Example 4, there was no excessive sludge attached to the carrier, and the treatment was satisfactorily performed.

In Example 5, as shown in FIG. 8, an experiment was performed using the same biological treatment apparatus as in Example 2 and providing fixed contact carriers in all biological treatment tanks. Six biological treatment tanks were arranged in series, and the organic wastewater was divided and flowed into two first biological treatment tanks a and b, and the air amount per tank was 0.4 m ³ / min. Table 12 shows the outline of the experimental apparatus and the experimental conditions.

The total tank capacity of the six tanks is 15 m ³ , the COD _Cr concentration of the organic wastewater is 1800 mg / L, the inflows of the first biological treatment tanks a and b are 9.0 m ³ / day and 8.3 m ³ / day, The COD _Cr volume load of the first biological treatment tanks a and b was adjusted to 6.5 kg / m ³ / day and 6.0 kg / m ³ / day.

Table 13 shows the experimental results. When treated under the conditions of Example 5, the SS at the outlet of the sixth tank was 100 mg / L, and the SS and COD _Cr of the treated water were 27 mg / L and 160 mg / L. The sludge conversion rate was 0.05 kg-SS / kg-COD _Cr . Dispersed bacteria were generated in the first biological treatment tank, and predation of the dispersed bacteria was performed in the second biological treatment tank. Since there were four second biological treatment tanks, predation of microorganisms was sufficiently performed, and the sludge conversion rate was lower than that in Example 2, and the treatment was performed well.

  As described above, according to the present invention, an organic wastewater capable of efficiently removing organic matter with a high load while reducing the amount of air for aerobic biological treatment and significantly reducing the amount of generated sludge. Biological treatment apparatus and biological treatment method can be provided.

M Organic matter load meter FC Inflow control valve

Claims (4)

Arrange multiple biological treatment tanks in multiple stages,
In the biological treatment tank of each stage, there is provided an inflow portion for inflowing organic wastewater or treated water treated in the biological treatment tank of the preceding stage, and a discharge portion for discharging treated water treated in the biological treatment tank. And
A sedimentation basin is provided at the latter stage of the biological treatment tank in the final stage, and the treated water treated in the biological treatment tank in the final stage flows in, and the biological treatment device for organic wastewater discharging the treated water subjected to sedimentation treatment,
In all the biological treatment tanks, a fixed contact carrier is arranged,
On the lower side than the position where the fixed contact carrier is arranged, an air diffuser is provided,
Arranging the inflow portion above the arrangement position of the fixed contact carrier,
Disposing the discharge portion below the position of the fixed contact carrier,
The biological treatment tank is divided into a first biological treatment tank into which the organic wastewater flows, and a second biological treatment tank into which the organic wastewater does not flow and the treated water from the preceding stage flows,
The treated water treated in the first biological treatment tank is passed through the second biological treatment tank ,
Further, an organic matter load measuring device for measuring the organic matter concentration and flow rate of the organic wastewater flowing into the first biological treatment tank,
An inflow rate adjusting unit that adjusts an inflow amount of the organic wastewater flowing into each of the biological treatment tanks configuring the first biological treatment tank based on a measurement value of the organic substance load measuring device,
The inflow amount adjusting means is configured such that, based on the measurement result of the organic matter load measuring device, the organic matter inflow load flowing into each biological treatment tank constituting the first biological treatment tank is ³ to 12 kg / m ³ / day of COD _Cr. A biological treatment apparatus for organic wastewater , wherein the inflow amount is adjusted so as to be as small as possible. The biological treatment device for organic wastewater according to claim 1 ,
The inflow amount adjusting means adjusts the inflow amount based on the measurement result of the organic matter load measuring device such that the organic matter load on all the biological treatment tanks becomes 0.75 to ³ kg / m ³ / day in COD _Cr. A biological treatment apparatus for organic wastewater, comprising: In a biological treatment method for organic wastewater that treats organic wastewater using a biological treatment device in which a plurality of biological treatment tanks are arranged in multiple stages,
In all of the biological treatment tanks, a fixed contact carrier is provided, and organic wastewater or treated water treated in the preceding biological treatment tank is introduced from above the position where the fixed contact carriers are disposed, and the inside of the biological treatment tank is introduced. In the process is performed while supplying air, having a biological treatment step of discharging the treated water treated from below the position of the fixed contact carrier,
The biological treatment step is divided into a first biological treatment step of introducing and treating organic wastewater and a second biological treatment step of introducing and treating treated water from the preceding stage without introducing organic wastewater,
Treating the treated water treated in the first biological treatment step in the second biological treatment step,
A sedimentation treatment step of sedimentation treatment water treated in the second biological treatment step ,
In the first biological treatment step, the concentration of organic matter and the flow rate of the organic wastewater flowing into the biological treatment tank are measured, and the amount of the organic wastewater is adjusted, and the amount of the organic wastewater is adjusted, A biological treatment method for organic wastewater, wherein the organic matter inflow load into each biological treatment tank constituting the first biological treatment step is performed so that COD _Cr becomes ³ to 12 kg / m ³ / day . The biological treatment method for organic wastewater according to claim 3 ,
The biological treatment of the organic wastewater is characterized in that the inflow of the organic wastewater is adjusted so that the organic matter load on all the biological treatment tanks becomes 0.75 to ³ kg / m ³ / day in COD _Cr. Method.

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