JPH10277582A - Sewage treatment equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage treatment apparatus capable of enhancing treatment efficiency. SOLUTION: This apparatus is provided with treatment tanks 16, 18 into which water to be treated is introduced, the air diffusion means 28, 31 arranged in the treatment tanks 16, 18, an air sending means 34 sending air obtained by sucking the atmosphere to the air diffusion means 28, 31 under pressure to diffuse air from the air diffusion means 28, 31 and mixing means 36, 37 mixing highly concn. oxygen gas with air sent under pressure from the air sending means 34. These mixing means 36, 37 raise the partial pressure of air after mixing within a range of 2.0% or less as compared with the partial pressure in the atmosphere. This air raised in the partial pressure of oxygen is diffused into water to be treated by the air diffusion means 28, 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sewage treatment apparatus for purifying sewage mainly by decomposing organic substances contained therein with microorganisms.

[0002]

2. Description of the Related Art As a sewage treatment apparatus for purifying sewage mainly by decomposing organic substances contained therein with microorganisms, a treatment tank into which water to be treated is introduced, and a diffuser provided in the treatment tank. There is also known a device having an air supply means for pressure-feeding air obtained by sucking the atmosphere to the air diffusing means and diffusing the air from the air diffusing means. This sewage treatment apparatus purifies the water to be treated by supplying oxygen to the microorganisms in the water to be treated by the air diffuser and actively maintaining the activity thereof.

[0003]

By the way, in the above-mentioned sewage treatment apparatus, the air supply means diffuses the air obtained by suctioning the atmosphere from the air diffusion means, so that more sewage treatment apparatus is used. If oxygen is required by the microorganisms, the amount of air will be increased to increase the amount of oxygen. However, if the amount of air to be diffused is increased in this manner, the water to be treated is excessively agitated and the frog is destroyed. Reproduction will be reduced.

[0004] For this reason, it has been considered to increase the amount of oxygen without increasing the amount of air by mixing high-concentration oxygen gas with the air fed from the air supply means. However, simply mixing high-concentration oxygen gas does not necessarily increase the activity of microorganisms, and thus has a problem that the treatment efficiency cannot be improved. Therefore, an object of the present invention is to provide a sewage treatment apparatus capable of improving treatment efficiency.

[0005]

In order to achieve the above object, a sewage treatment apparatus according to claim 1 of the present invention comprises a treatment tank into which water to be treated is introduced, and a diffuser provided in the treatment tank. And air supply means for pressure-feeding the air obtained by suctioning the atmosphere to the air diffusion means and diffusing the air from the air diffusion means. A mixing means for mixing high-concentration oxygen gas is provided, and the mixing means increases the oxygen partial pressure in the mixed air within 2.0% of the oxygen partial pressure in the atmosphere. I have. This allows the air diffuser to diffuse the air whose oxygen partial pressure has been raised within a range of 2.0% or less than the oxygen partial pressure in the atmosphere to the water to be treated, thereby improving the treatment efficiency. .

In addition to the above, a sewage treatment apparatus according to a second aspect of the present invention further comprises a plurality of treatment tanks having the aeration means and connects these treatment tanks in series to sequentially treat the water to be treated. The mixing means is further characterized in that the high-concentration oxygen gas is mixed only into the air fed from the air supply means to the air diffusion means in the upstream processing tank. Accordingly, in the case where a plurality of processing tanks having the air diffuser are provided, the high-concentration oxygen gas is mixed only with the air that is highly contaminated and that is pressure-fed from the air supply unit to the air diffuser of the upstream processing tank. Therefore, in a case where the supply amount of the high-concentration oxygen gas is limited in terms of capacity or cost, the wastewater treatment can be efficiently performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a sewage treatment apparatus according to the present invention will be described below with reference to FIGS. The sewage treatment apparatus 11 includes a sewage regulating tank 12 into which treated water (sewage) 10 is first introduced, and a pump 1 that pumps up and discharges the treated water 10 from the sewage regulating tank 12 through a pipeline 13.
4, a primary aeration tank (treatment tank) 16 into which the water to be treated 10 discharged from the pump 14 via the conduit 13 is introduced;
A pipe 17 for guiding the water 10 to be treated in the primary aeration tank 16, a secondary aeration tank (treatment tank) 18 into which the water 10 to be treated guided by the pipe 17 is introduced, and a secondary aeration tank 18 Water to be treated 10
And the water to be treated 10 guided by the pipe 19
And a sedimentation tank 20 into which is introduced. Thus, the sewage adjustment tank 12, the primary aeration tank 16, the secondary aeration tank 18
The sedimentation tank 20 is arranged in series on the flow of the water 10 to be treated.

The sewage adjusting tank 12 adjusts the water 10 to be treated to a uniform concentration. The water 10 to be treated, which has been adjusted to such a uniform concentration, is pumped up by the pump 14. The primary aeration tank 16 has a cylindrical shape with an open top and a bottom, and forms organic matter contained in the water to be treated 10 introduced from the sewage adjustment tank 12 on the upstream side into sludge of the water to be treated 10. Decomposed and purified by microorganisms.

The secondary aeration tank 18 has a cylindrical shape with an open top and a bottom. The organic matter contained in the water 10 to be treated introduced from the primary aeration tank 16 on the upstream side thereof (which is decomposed in the primary aeration tank 16). The unremoved organic matter) is decomposed and purified by microorganisms forming sludge of the water 10 to be treated. In addition, as the pipe line 17 from the primary aeration tank 16 to the secondary aeration tank 18,
For example, one that causes the water 10 to be treated in the primary aeration tank 16 to flow down to the secondary aeration tank 18 by gravity, for example, is used.

The sedimentation tank 20 has a secondary aeration tank 1 on the upstream side thereof.
The sludge of the water to be treated 10 introduced from 8 is settled and separated, and the supernatant is discharged as treated water. In addition, as the pipe line 19 from the secondary aeration tank 18 to the sedimentation tank 20, one that causes the water 10 to be treated in the secondary aeration tank 18 to flow down to the sedimentation tank 20 by gravity, for example, is used. A sludge return pipe 21 is connected between the bottom 20 a of the settling tank 20 and the bottom 16 a of the primary aeration tank 16, and the sludge return pipe 21 is settled in the settling tank 20. A pump 22 for sucking sludge and discharging the sludge to the primary aeration tank 16 is provided.

A pipe 24 is introduced vertically into the sewage adjustment tank 12 from above, and a diffuser pipe extending horizontally at a lower end of the pipe 24 at a position slightly above the bottom 12 a of the sewage adjustment tank 12. 25 are connected. The air diffuser 25 has a large number of air diffusion holes (not shown) that penetrate inside and outside.

A pipe 27 is vertically introduced into the primary aeration tank 16 from above, and a lower end of the pipe 27 has a diffuser pipe extending horizontally at a position slightly above the bottom 16 a of the primary aeration tank 16. (Aeration means) 28 is connected. The air diffusion tube 28 has a large number of air diffusion holes (not shown) that penetrate inside and outside.

A pipe 30 is introduced vertically into the secondary aeration tank 18 from above. The lower end of the pipe 30 extends horizontally at a position slightly above the bottom 18 a of the secondary aeration tank 18. An air diffuser (air diffuser) 31 is connected. The air diffusion tube 31 has a large number of air diffusion holes (not shown) that penetrate inside and outside.

The pipes 24, 27, and 30 are connected to a single pipe 33 on the opposite side of the air diffusers 25, 28, and 31, respectively. A blower (air sending means) 34 is provided for sending the air obtained by sucking the atmosphere through the pipe 33 and the pipes 24, 27, 30 toward the diffuser pipes 25, 28, 31.

A mixer (mixing means) 36 is disposed at a position downstream of the blower 34 of the pipe 33 and upstream of all the pipes 24, 27, 30.
On the other hand, an oxygen gas generator (mixing means) 37 for generating high-concentration oxygen gas by condensing oxygen in the compressed air is connected to the mixer 36. Means that the high-concentration oxygen gas generated by the oxygen gas generator 37 is mixed with the air obtained by sucking the air, which is pressure-fed from the blower 34.

The mixed air having the oxygen partial pressure higher than the oxygen partial pressure in the atmosphere is mixed with the air diffuser 25,
The air is diffused from 28 and 31. The oxygen gas generator 37 can control the flow rate of the high-concentration oxygen gas, and thus can control the oxygen partial pressure after mixing in the mixer 36. An oxygen concentration meter (mixing means) 39 is arranged at a position downstream of the mixer 36 in the pipe 33 and upstream of all the pipes 24, 27, 30. The oxygen concentration meter 39 detects the oxygen concentration of the air in the pipeline 33 and outputs the detected oxygen concentration to a control unit (mixing means) 40.

The control unit 40 includes an oxygen concentration meter 39
From the detection result, the oxygen partial pressure of the air in the pipeline 33 is increased from the oxygen partial pressure in the atmosphere within a range of more than 0% and within 2.0%, in other words, the oxygen partial pressure in the atmosphere is Since it is normally 20.9%, the oxygen gas is supplied from the oxygen gas generator 37 to the mixer 36 so that the oxygen partial pressure of the air in the pipe line 33 is larger than 20.9% and within 22.9%. The supply amount of high concentration oxygen gas is controlled. In addition, the pressure that should be shown when each of the component gases constituting the mixed gas is assumed to have occupied the entire volume by itself after removing other components is called the partial pressure of the component gas, and isothermic isothermal pressure When several kinds of ideal gases are mixed at the same temperature and the same pressure to form one gas, the volume occupied by the mixed gas (total volume) is the sum of the volumes occupied by each gas before mixing. The pressure of the gas mixture is equal and the total pressure is based on the law of partial pressure (Dalton's law), which represents a relationship equal to the sum of the gases.

The primary aeration tank 16 and the secondary aeration tank 18 are provided with dissolved oxygen concentration meters 42 and 43, respectively. The dissolved oxygen concentration meter 42 measures the dissolved oxygen concentration of the water 10 to be treated in the primary aeration tank 16. Is detected and output to the control unit 40, and the dissolved oxygen concentration meter 43 detects the dissolved oxygen concentration of the water 10 to be treated in the secondary aeration tank 18 and outputs the same to the control unit 40. In addition, the control unit 40 includes the dissolved oxygen concentration meter 4.
The oxygen partial pressure of the air in the pipeline 33 is maintained in the above range so that the dissolved oxygen concentration in the primary aeration tank 16 and the secondary aeration tank 18 is optimized from the detection results of 2, 43,
Further, the supply amount of the high-concentration oxygen gas from the oxygen gas generator 37 to the mixer 36 is controlled.

In the sewage treatment apparatus 11 configured as described above, the water 10 to be treated is first introduced into the sewage adjustment tank 12 and adjusted to have a uniform concentration. At the same time, the organic substances contained therein are decomposed and purified by the microorganisms forming the sludge of the water 10 to be treated. Here, air whose oxygen partial pressure has been increased to an optimum state is diffused from the blower 34 and the oxygen gas generator 37 through the mixer 36 into the sewage adjusting tank 12 through the air diffuser 25. Thereby, oxygen can be supplied to the microorganisms in the water to be treated 10 at the optimal oxygen partial pressure, the activity can be actively maintained, and the purification can be performed efficiently.

Thereafter, the water 10 to be treated in the sewage adjusting tank 12 is
Is introduced into a primary aeration tank 16 via a pipe 13 by a pump 14. In the primary aeration tank 16, the organic matter contained in the introduced water to be treated 10 is removed from the water to be treated 1.
It is decomposed and purified by microorganisms forming sludge of zero. Again, the blower 34 and the oxygen gas generator 37
The air whose oxygen partial pressure has been increased to an optimal state is diffused from the air diffuser 28 into the primary aeration tank 16 through the mixer 36, so that the optimal oxygen partial pressure for the microorganisms in the water 10 to be treated is increased. To supply oxygen to maintain the activity actively and to purify efficiently.

The treated water 10 purified in the primary aeration tank 16 is introduced into a secondary aeration tank 18 via a pipe 17. In the secondary aeration tank 18 as well, the organic substances contained in the introduced water to be treated 10 are removed from the water to be treated 1
It is decomposed and purified by microorganisms forming sludge of zero. Again, the blower 34 and the oxygen gas generator 37
The air whose oxygen partial pressure has been increased to the optimum state is diffused from the air diffuser 31 into the secondary aeration tank 18 through the mixer 36, so that the oxygen content optimal for the microorganisms in the water 10 to be treated is increased. Oxygen can be supplied under pressure to maintain the activity actively and to purify efficiently.

The treated water 10 purified in the secondary aeration tank 18 is introduced into a settling tank 20 via a pipe 19. Then, in the sedimentation tank 20, the introduced treated water 1
The sludge settled in the settling tank 20 is returned to the primary aeration tank 16 by the pump 22 while the supernatant is discharged as treated water.

It should be noted that a flow rate regulator for making the flow rate of the water 10 to be treated constant may be provided on the side of the primary aeration tank 16 of the pump 14 in the pipeline 13. In addition, sewage adjustment tank 12, primary aeration tank 1
An alkaline agent such as caustic soda may be introduced into at least one of the secondary aeration tank 18 and the secondary aeration tank 18. Further, a cylinder in which high-concentration oxygen gas is stored may be provided instead of the oxygen gas generator 37.

Next, the point that the oxygen partial pressure in the air after mixing by the mixer 36 is increased within 2.0% of the oxygen partial pressure in the atmosphere will be described. First, as an experimental device,
As shown in FIG. 2, four palindrome processing water tanks (aeration tanks) 4
5 to 48 are arranged, and pipes 50 to 53 are respectively introduced into the treated water tanks 45 to 48. Air gas flow meters 55 to 58 are installed outside the treated water tanks 45 to 48 of the respective pipes 50 to 53. Further, each of the pipes 50 to 53 is connected to an air pump 59, and an oxygen cylinder 60 is connected to the pipes 50 to 52.
Are connected via pipes 61 to 63, and oxygen gas flow meters 65 to 67 are provided on the pipes 61 to 63, respectively.

Then, 1 L of water to be treated containing microorganisms, about 1.5 g of a non-woven fabric as a microorganism carrier and a dry weight of about 1.5 g, and 3 L of distilled water having a volume of 5 L (filling water amount of about 4 L)
L) was prepared as each of the above treated water tanks 45 to 48. Further, after weighing 0.341 g of glutamic acid and glucose respectively, an aqueous solution prepared by measuring up to 1 L with pure water was prepared as artificial sewage, and 100 mL of the artificial sewage was added to each of the treatment tanks 45 to 48. At this time, the total amount of organic carbon (TOC) in each of the treatment water tanks 45 to 48 was about 24 to 27 mg / L.

The concentration from the oxygen cylinder 60
9% oxygen gas and air from the air pump 59 were supplied at a total flow rate of 4%.
The mixture was mixed at a flow rate of 00 mL / min.
48 was aerated through lines 50-53. The oxygen gas flow rates are 0.1 mL, 4 mL, and 8 mL, respectively (the ratio of the oxygen gas flow rate to the air flow rate is 0% and 0.25, respectively).
%, 1%, 2%). In order to keep the environment of the experiment constant, the treated water tanks 45 to 48 were allowed to stand in a constant temperature bath maintained at an ambient temperature of 25 ° C. and a relative humidity of 60%. As a result, the water temperature in the treated water tanks 45 to 48 was reduced. It was kept at about 28 ° C.

Under the above conditions, each of the treated water tanks 45 to 4
8, TOC and dissolved oxygen concentration (D
O) and the results of measuring the hydrogen ion concentration pH and water temperature are shown in the chart of FIG.
The change of OC is shown in the characteristic diagram of FIG. 4, and the relationship between the oxygen partial pressure and the removal rate is shown in the characteristic diagram of FIG. In FIGS. 3 and 4, TOC was reached after 43.9 hours had elapsed.
The increase is due to the addition of artificial sewage.
Then, after adding artificial sewage at the time of 43.9 hours shown in FIGS. 3 and 4, T at the time of 65.6 hours has passed.
Looking at the removal rate of OC, the air (oxygen partial pressure rise 0
%), The TOC is 28.4 to 17.8 and the removal rate is 37.3%, while the TOC is 0.25%
With respect to the case where the oxygen partial pressure was increased, the TOC was 28.
2 to 11.3, the removal rate was as high as 59.9%, and TOC was increased from 26.8 to 10% even in the case where the oxygen partial pressure was increased by 1.0% from the atmosphere. .
5, the removal rate is as high as 60.8%, and the TOC from 27.2 to 13.4 for the one with 2.0% higher oxygen partial pressure than the atmosphere. The removal rate is 50.7%, which is satisfactory. From this result, as shown in FIG. 5, when the oxygen partial pressure was increased within a range of 2.0% or less as compared with the atmosphere, a sufficient TOC removal rate could be secured. It can be seen that is working well.

As described above, according to the sewage treatment apparatus of the first embodiment, the oxygen partial pressure is 2.0 times higher than the atmospheric oxygen partial pressure.
By spreading the air that has been raised within the range of not more than 10% to the water to be treated 10 in the primary aeration tank 16 and the secondary aeration tank 18, the treatment efficiency can be improved.

Next, a second embodiment of the sewage treatment apparatus 11 of the present invention will be described below with reference to FIG. 6, focusing on differences from the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the second embodiment, the blower 34 and each pipe 2
The mixer 36 is provided on a line 33 connecting the
Accordingly, the oxygen gas generator 37 is not connected to the pipe 33 in accordance with this.

The mixer 36 is provided in the pipe 27 introduced into the primary aeration tank 16 upstream of the secondary aeration tank 18. An oxygen gas generator 37 is connected to the mixer 36 as in the first embodiment.
Thereby, the high-concentration oxygen gas generated by the oxygen gas generator 37 is supplied only to the air obtained by suctioning the air, which is pressure-fed from the blower 34 to the air diffuser 25 of the primary aeration tank 16. Will be mixed. Correspondingly, the oximeter 39 is located downstream of the mixer 36 in line 33 and not in a position upstream of all the lines 24, 27, 30 but in the mixer 36 in line 27. It is located at the downstream position.

The control unit 40 controls the oxygen partial pressure of the air in the pipe 27 of the primary aeration tank 16 to be greater than 0% and less than 2.0% of the oxygen partial pressure in the atmosphere based on the detection result of the oxygen concentration meter 39. In other words, since the oxygen partial pressure in the atmosphere is 20.9%, the oxygen partial pressure of the air in the pipeline 27 is larger than 20.9% and within 22.9%. Thus, the supply amount of the high-concentration oxygen gas supplied from the oxygen gas generator 37 to the mixer 36 is controlled.

In the sewage treatment apparatus 11 configured as described above, a plurality of primary aeration tanks 16 and secondary aeration tanks 18 are provided.
Is provided, the high-concentration oxygen gas is mixed only with the air that is pressure-fed from the blower 34 into the air diffuser 28 of the primary aeration tank 16 on the upstream side, where the degree of contamination is high, so that the high-concentration or cost-effective In a case where the supply amount of the oxygen gas is limited, the wastewater treatment can be efficiently performed. Although the supply amount of the high-concentration oxygen gas is larger than that in this case, mixing with all the air diffused to the sewage adjustment tank 12, the primary aeration tank 16 and the secondary aeration tank 18 requires an efficient or costly method. In the case where the supply amount of the high-concentration oxygen gas is limited in particular, if the high-concentration oxygen gas is mixed only with the air pumped to the primary aeration tank 16 and the secondary aeration tank 18, the wastewater treatment can be efficiently performed. It can be carried out.

[0033]

As described in detail above, claim 1 of the present invention
According to the sewage treatment apparatus described above, the air diffuser diffuses the air whose oxygen partial pressure is increased within a range of 2.0% or less than the oxygen partial pressure in the atmosphere into the water to be treated, Processing efficiency can be improved.

Further, according to the sewage treatment apparatus of the second aspect of the present invention, when a plurality of treatment tanks having air diffusion means are provided, the air diffusion means of the upstream processing tank having a high degree of contamination is provided. Since the high-concentration oxygen gas is mixed only with the air fed from the air supply means, the wastewater treatment can be performed efficiently when the supply amount of the high-concentration oxygen gas is limited in terms of efficiency or cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a first embodiment of a sewage treatment apparatus of the present invention.

FIG. 2 is a configuration diagram schematically showing an experimental apparatus for sewage treatment.

FIG. 3 shows experimental results obtained by an experimental apparatus for sewage treatment, in which total organic carbon content (TOC), dissolved oxygen concentration (DO), hydrogen ion concentration (pH), and water temperature are measured with respect to aeration time in each treatment water tank. 6 is a table showing the results.

FIG. 4 is a characteristic diagram showing a result of an experiment using an experimental apparatus for sewage treatment, showing a change in a total amount of organic carbon (TOC) with respect to an aeration time.

FIG. 5 is a characteristic diagram showing a result of an experiment using an experimental apparatus for sewage treatment, showing a relationship between a partial pressure of oxygen and a removal rate.

FIG. 6 is a configuration diagram schematically showing a second embodiment of the sewage treatment apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 To-be-processed water 11 Sewage treatment apparatus 12 Sewage adjustment tank 16 Primary aeration tank (processing tank) 18 Secondary aeration tank (processing tank) 28, 31 Aeration pipe (aeration means) 34 Blower (aeration means) 36 Mixer ( Mixing means) 37 oxygen gas generator (mixing means) 40 control unit (mixing means)

Claims (2)

[Claims] 1. A treatment tank into which water to be treated is introduced, an air diffuser provided in the treatment tank, and air obtained by suctioning the air is pressure-fed to the air diffuser to diffuse the air. And a gas supply means for diffusing air from the wastewater treatment apparatus, comprising: a mixing means for mixing high-concentration oxygen gas into the air fed from the gas supply means; A sewage treatment apparatus characterized in that the oxygen partial pressure is raised within a range of 2.0% or less than the oxygen partial pressure in the atmosphere. 2. A plurality of treatment tanks having the aeration means are provided, and the treatment tanks are connected in series to move water to be treated in order. 2. The sewage treatment apparatus according to claim 1, wherein high-concentration oxygen gas is mixed only into the air fed from said air supply means to said means.