JP2017154105A - Wastewater treatment ability improving agent and method for producing the same, and wastewater treatment method and wastewater treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wastewater treatment ability improving agent that allows stabler treatment in wastewater treatment using active sludge.SOLUTION: The present invention provides a wastewater treatment ability improving agent for improving wastewater treatment performance of sludge, the agent comprising lyophilized sludge comprising acclimatized sludge, and a cationic flocculant carried on the lyophilized sludge.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a wastewater treatment performance improver, a method for producing the same, a wastewater treatment method, and a wastewater treatment apparatus.

In wastewater treatment, wastewater may be purified by performing biological treatment using activated sludge.
For example, Patent Document 1 discloses that laundry wastewater discharged from a plant facility is introduced into a biological treatment tank, and the laundry wastewater is treated by aeration and mixing with activated sludge in the biological treatment tank. ing.
Patent Document 2 discloses a freeze-dried sludge obtained by freeze-drying a conditioned activated sludge in order to recover the biological treatment capacity when the biological treatment capacity of the activated sludge for treating laundry wastewater is reduced. Is added to activated sludge.

Japanese Patent Laid-Open No. 2002-210486 International Publication No. 2015/145866

When the freeze-dried sludge described in Patent Document 2 is used, the biological treatment capacity can be recovered when the biological treatment capacity of the activated sludge for treating laundry wastewater is reduced.
However, according to the knowledge of the present inventors, when the freeze-dried sludge described in Patent Document 2 is used, the freeze-dried sludge is likely to flow out of a biological treatment tank for biological treatment, and stable biological treatment is difficult. It turns out that there is a case.
Therefore, it is desired to more stably perform biological treatment of wastewater with activated sludge.

  In view of the above-described circumstances, at least one embodiment of the present invention aims to provide a wastewater treatment performance improver that enables more stable treatment in wastewater treatment using activated sludge.

(1) The wastewater treatment performance improver according to at least one embodiment of the present invention is:
A wastewater treatment performance improver for improving sludge wastewater treatment performance,
Freeze-dried sludge containing familiar sludge,
A cationic flocculant supported on the freeze-dried sludge;
Is provided.

As a result of intensive studies by the present inventors, when freeze-dried sludge that does not contain a cationic flocculant is used in a biological treatment tank, the freeze-dried sludge may not sufficiently settle in the biological treatment tank. In some cases, freeze-dried sludge may flow out of the biological treatment tank. This is considered to be due to the following reason.
That is, sludge is generally negatively charged. Here, when a negatively-charged freeze-dried sludge is added to a negatively-charged sludge floc, both of them repel each other electrically, so that the freeze-dried sludge is difficult to combine with the sludge floc. For this reason, freeze-dried sludge having a relatively small particle size tends to flow along with the wastewater to be treated.
As described above, lyophilized sludge that has flowed out of the biological treatment tank cannot contribute to biological treatment in the biological treatment tank. Therefore, when lyophilized sludge flows out of the biological treatment tank, activated sludge in the biological treatment tank is used. The biological treatment performance by decreases.
In this respect, the wastewater treatment capacity improving agent (1) above contains a cationic flocculant supported on freeze-dried sludge, so that the freeze-dried sludge is positively charged. Easy to combine. Therefore, according to the wastewater treatment performance improver of (1) above, freeze-dried sludge is likely to stay in the biological treatment tank by being electrically coupled to sludge having a relatively large particle size (sludge floc). For this reason, the wastewater to be treated can be more stably treated in the biological treatment tank.

(2) In some embodiments, in the configuration of the above (1), the cationic flocculant includes a cationic polymer.
(3) In some embodiments, the cationic polymer includes a polydicyandiamide-based polymer.
According to the configuration of (2) or (3) above, wastewater treatment in a biological treatment tank can be effectively performed by a wastewater treatment performance improver containing a cationic polymer.

(4) A method for producing a wastewater treatment performance improver according to at least one embodiment of the present invention,
Acclimatize sludge and get the familiar sludge;
Mixing the acclimatized sludge and the cationic flocculant to obtain a mixture;
Lyophilizing the mixture to obtain a wastewater treatment performance improver;
Is provided.

  Since the wastewater treatment performance improver obtained by the method (4) includes a cationic flocculant supported on freeze-dried sludge, the freeze-dried sludge is positively charged. Easy to couple electrically. Therefore, according to the wastewater treatment performance improver, freeze-dried sludge is likely to stay in the biological treatment tank by being electrically coupled to sludge having a relatively large particle size (sludge floc). That is, according to the method (4), it is possible to obtain a wastewater treatment performance improver that can more stably treat wastewater to be treated in a biological treatment tank.

(5) In some embodiments, in the method of (4) above,
Further comprising dehydrating the mixture to obtain a dehydrated cake;
In the step of obtaining the wastewater treatment capacity improver, the dehydrated cake is freeze-dried.
In the above method (5), in the mixture of the adapted sludge and the cationic flocculant, the electric action of the negatively charged adapted sludge and the cationic flocculant promotes the aggregation of the mixture, and the size of the aggregate is reduced. growing. For this reason, in the process of dehydrating the mixture, the filter medium (for example, filter cloth) is less likely to be clogged, and the dehydration efficiency is improved. Therefore, according to the method (5), the wastewater treatment performance improver can be produced efficiently.

(6) The waste water treatment method according to at least one embodiment of the present invention includes:
Adding the wastewater treatment performance improver according to any one of (1) to (3) above to sludge;
Biologically treating the wastewater using the sludge to which the wastewater treatment performance improver has been added;
Is provided.

  Since the wastewater treatment performance improving agent described in the above (1) to (3) includes a cationic flocculant supported on freeze-dried sludge, the freeze-dried sludge is positively charged. ) And is easily electrically coupled. Therefore, according to the above method (6), since the wastewater treatment performance improver is used, the lyophilized sludge is electrically coupled to sludge having a relatively large particle size (sludge floc), thereby being a biological treatment tank. It ’s easier to stay inside. For this reason, the wastewater to be treated can be more stably treated in the biological treatment tank.

(7) In some embodiments, the method of (6) further includes a step of acclimatizing the sludge to which the wastewater treatment performance improver is added.
According to the method (7), since the sludge containing freeze-dried sludge is adapted, it can be adapted in a short period of time compared to the case where the sludge not containing freeze-dried sludge is adapted.

(8) In some embodiments, in the method of (6) or (7), in the step of adding the wastewater treatment performance improver, when the wastewater treatment performance is reduced by the sludge, Add a wastewater treatment capacity improver.
According to the above method (8), since the wastewater treatment performance improver is added to the sludge when the wastewater treatment performance by the sludge is reduced, the wastewater treatment performance by the sludge can be recovered.

(9) In some embodiments, in any one of the above methods (6) to (8), the ratio of the added amount of the wastewater treatment capacity improver to the sludge with respect to the amount of the sludge (the wastewater treatment capacity The addition amount of the improver / the amount of the sludge) is 1/19 or more and 1/1 or less in terms of MLSS.
In the above method (9), the ratio of the added amount of the wastewater treatment capacity improver to the sludge with respect to the amount of sludge is set to 1/19 or more in terms of MLSS, so that the wastewater treatment performance of sludge can be effectively improved. it can. In addition, in the method (9), the ratio of the amount of the waste water treatment capacity improver added to the sludge relative to the amount of sludge is set to 1/1 or less in terms of MLSS, so that the outflow of freeze-dried sludge is more effectively suppressed. can do.

(10) In some embodiments, the method according to any one of (6) to (9) further includes a step of filtering the biologically treated wastewater by membrane separation.
By filtering wastewater biologically treated with activated sludge by membrane separation, the outflow of sludge contained in the wastewater may be suppressed.
In this respect, the method (10) uses sludge to which a wastewater treatment performance improver is added in the biological treatment of wastewater. Therefore, sludge is produced by the electrical action of negatively charged sludge and positively charged freeze-dried sludge. Aggregation is promoted, and the size of the aggregate increases. For this reason, in the process of filtering biologically treated wastewater by membrane separation, the filter used for membrane separation is less likely to be blocked, and the flow rate of treated wastewater that passes through the filter is unlikely to decrease. Therefore, according to the above method (10), the waste water to be treated can be treated more efficiently.

(11) The waste water treatment apparatus according to at least one embodiment of the present invention is:
A drainage tank for storing wastewater to be treated;
A biological treatment tank for subjecting the wastewater from the wastewater tank to a biological treatment by aeration mixing with activated sludge to which the wastewater treatment performance improving agent according to any one of (1) to (3) is added;
A treated water tank for storing treated wastewater treated in the biological treatment tank;
Is provided.

  Since the wastewater treatment performance improving agent described in the above (1) to (3) includes a cationic flocculant supported on freeze-dried sludge, the freeze-dried sludge is positively charged. ) And is easily electrically coupled. Therefore, according to the configuration of the above (11), the wastewater to be treated is aerated and mixed with the activated sludge to which the above-described wastewater treatment performance improver is added, so that the lyophilized sludge has a relatively large particle size. It becomes easy to stay in the biological treatment tank by being electrically coupled to sludge (sludge floc). For this reason, the wastewater to be treated can be more stably treated in the biological treatment tank.

(12) In some embodiments, in the configuration of (4) above,
Further comprising a separation membrane for filtering the treated waste water,
The treated water tank is configured to store the treated wastewater filtered by the separation membrane.
In the configuration of (12), since sludge to which a wastewater treatment performance improver is added is used in biological treatment of wastewater, sludge aggregation is caused by the electrical action of negatively charged sludge and positively charged freeze-dried sludge. Promoted to increase the size of the aggregate. For this reason, the separation membrane (filter) for filtering the biologically treated wastewater is not easily blocked, and the flow rate of the treated wastewater passing through the separation membrane (filter) is unlikely to decrease. Therefore, according to the configuration of (12) above, the wastewater to be treated can be treated more efficiently.

(13) In some embodiments, in the above configuration (11) or (12),
A detection unit for detecting wastewater treatment performance in the biological treatment tank;
Based on the detection result by the detection unit, a supply unit configured to further add the wastewater treatment capacity improver to the biological treatment tank,
Is further provided.
According to the configuration of (13), since the wastewater treatment performance improver is added based on the detection result of the wastewater treatment performance in the biological treatment tank, the wastewater treatment performance due to sludge can be effectively recovered. For example, the wastewater treatment performance by sludge can be appropriately recovered by adding a wastewater treatment performance improver to the sludge when the wastewater treatment performance by sludge is reduced.

(14) In some embodiments, in the configuration of (13), the detection unit includes a COD measurement unit for measuring COD (chemical oxygen demand) of the wastewater in the biological treatment tank.
According to the configuration of (14) above, the wastewater treatment performance improver can be appropriately added as necessary based on the measurement result of the COD of the wastewater in the biological treatment tank. Therefore, the wastewater treatment performance with sludge can be recovered while suppressing the amount of the wastewater treatment performance additive added.

  According to at least one embodiment of the present invention, there is provided a wastewater treatment capacity improver that enables more stable treatment in wastewater treatment using activated sludge.

It is a schematic block diagram of the waste water treatment equipment concerning one embodiment. It is a schematic diagram of the sludge to which the waste water treatment ability improving agent which concerns on one Embodiment was added. It is a schematic diagram of the sludge to which the conventional waste water treatment capacity improvement agent was added. It is a flowchart of the manufacturing method of the waste water treatment performance improving agent which concerns on one Embodiment. It is a flowchart of the waste water treatment method which concerns on one Embodiment. It is a flowchart of the waste water treatment method which concerns on one Embodiment. It is a figure which shows the structure of the testing apparatus of the waste water treatment test used by the test example. It is a graph which shows the result of having performed the wastewater treatment test in the test example. It is a graph which shows the result of having performed the wastewater treatment test in the test example. It is a graph which shows the elapsed time and COD density | concentration in a test example. It is a graph which shows the elapsed time and COD density | concentration in a test example.

  Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.

First, the outline | summary of the waste water treatment apparatus to which the waste water treatment ability improving agent which concerns on some embodiment is applied is demonstrated.
FIG. 1 is a schematic configuration diagram of a wastewater treatment apparatus according to an embodiment. As shown in FIG. 1, the wastewater treatment apparatus 1 according to an embodiment is an apparatus for treating laundry wastewater 8, and includes a drainage tank 10, a biological treatment tank 12, and a treated water tank 16. .
The drainage tank 10 stores wastewater to be treated. The wastewater stored in the drainage tank 10 is sent to the biological treatment tank 12 where it is aerated and mixed with activated sludge in the biological treatment tank 12 for biological treatment. The treated wastewater treated in the biological treatment tank 12 is sent to the treated water tank 16.
The configuration of the waste water treatment apparatus 1 will be described in detail later.

Here, the wastewater to be treated by the wastewater treatment apparatus 1 may be, for example, laundry wastewater that is discharged when clothes are washed. This washing wastewater may be, for example, a washing wastewater that is discharged when the work clothes of workers of the plant facility are washed. In this case, the laundry wastewater contains, for example, organic substances such as detergents, cloth fibers, fats or carbohydrates, or trace amounts of radioactive substances. In the wastewater treatment apparatus 1, biological treatment of wastewater to be treated is performed in the biological treatment tank 12 in order to reduce the concentration of these substances.
In the biological treatment in the biological treatment tank 12, the wastewater to be treated is aerated and mixed with activated sludge to which the wastewater treatment performance improver according to one embodiment is added.

Next, the wastewater treatment performance improver and its manufacturing method according to some embodiments will be described.
The wastewater treatment capacity improving agent according to one embodiment includes a freeze-dried sludge containing an acclimatized sludge and a cationic flocculant supported on the freeze-dried sludge.

The wastewater treatment performance improver can be used to improve the wastewater treatment performance of sludge when biologically treating the wastewater with sludge.
For example, the activated sludge obtained by acclimatizing the sludge to which the wastewater treatment capacity improving agent according to one embodiment is added can be used in the biological treatment in the wastewater treatment apparatus 1 described above. In this case, the time required for acclimatization of sludge can be shortened.
Or when the waste water treatment performance by the waste water treatment apparatus 1 mentioned above falls, the waste water treatment performance improving agent which concerns on one Embodiment can be added to the sludge of the biological treatment tank 12. FIG. In this case, the wastewater treatment performance by the wastewater treatment apparatus 1 can be recovered.

Here, with reference to FIG. 2A and FIG. 2B, the effect | action and effect of the waste water treatment capacity improvement agent which concern on embodiment are demonstrated. FIG. 2A is a schematic diagram of sludge to which a wastewater treatment capacity improver according to an embodiment is added, and FIG. 2B is a schematic diagram of sludge to which a conventional wastewater performance performance improver is added.
The conventional wastewater treatment performance improver is, for example, a lyophilized sludge obtained by lyophilizing a conditioned activated sludge, and is a lyophilized sludge that does not contain a cationic flocculant.

  As a result of intensive studies by the present inventors, for example, in the wastewater treatment apparatus 1 described above, a conventional wastewater treatment performance improver (freeze-dried sludge 4) (see FIG. 2B) that does not contain a cationic flocculant is used in the biological treatment tank 12. When used, the freeze-dried sludge 4 may not sufficiently settle in the biological treatment tank 12. For example, the freeze-dried sludge 4 may flow out of the biological treatment tank 12 when continuously passing water. I found out. This is considered to be due to the following reason.

That is, sludge (including dry frozen sludge) is generally negatively charged. Here, as shown in FIG. 2B, when the negatively-charged freeze-dried sludge 4 (conventional wastewater treatment performance improver) is added to the negatively-charged sludge floc 2, the two are electrically repelled and thus frozen. The dried sludge 4 is difficult to combine with the sludge floc 2. For this reason, the freeze-dried sludge 4 having a relatively small particle size easily flows along with the wastewater to be treated.
As described above, the freeze-dried sludge 4 that has flowed out of the biological treatment tank 12 cannot contribute to biological treatment in the biological treatment tank 12, and therefore when the freeze-dried sludge 4 flows out of the biological treatment tank 12, The biological treatment performance by the activated sludge in the treatment tank 12 is lowered.

  In this regard, as shown in FIG. 2A, since the wastewater treatment capacity improving agent 5 according to one embodiment includes a cationic flocculant supported on lyophilized sludge, the lyophilized sludge is positively charged. It is easy to be electrically coupled with sludge (sludge floc 2). Therefore, according to the wastewater treatment performance improver 5, freeze-dried sludge is likely to stay in the biological treatment tank 12 by being electrically coupled to sludge having a relatively large particle size (sludge floc 2). For this reason, the wastewater to be treated can be more stably treated in the biological treatment tank 12.

In one embodiment, the cationic flocculant constituting the wastewater treatment performance improver 5 may be a flocculant containing a cationic polymer. Such a cationic polymer may be, for example, a polydicyandiamide-based polymer.
Alternatively, in one embodiment, the cationic flocculant constituting the wastewater treatment performance improver 5 may be a cationic substance other than a polymer, for example, polyaluminum chloride, aluminum sulfate, iron, or the like. Good.

  FIG. 3 is a flowchart of a method for manufacturing the wastewater treatment performance improver 5 according to an embodiment. As shown in FIG. 3, in the manufacturing method of the wastewater treatment performance improving agent 5 according to one embodiment, first, the sludge is acclimated to obtain the acclimated sludge (S12). Next, the adapted sludge obtained in step S12 and the cationic flocculant are mixed to obtain a mixture of the adapted sludge and the cationic flocculant (S14). Next, the mixture obtained in step S14 is dehydrated to obtain a dehydrated cake (S16). And the dewatering cake of the mixture obtained by step S16 is freeze-dried, and the waste-water-treatment capacity improvement agent 5 is obtained. The thus obtained wastewater treatment performance improver 5 includes freeze-dried sludge containing acclimatized sludge and a cationic flocculant supported on the freeze-dried sludge.

  Since the wastewater treatment capacity improving agent 5 obtained by the above-described production method contains a cationic flocculant supported on freeze-dried sludge, the freeze-dried sludge is positively charged. Therefore, the negatively-charged sludge (sludge floc) and electric Easy to combine. Therefore, according to the wastewater treatment performance improver 5, the freeze-dried sludge is likely to stay in the biological treatment tank 12 (see FIG. 1) by being electrically coupled to sludge having a relatively large particle size (sludge floc). Become. That is, according to the manufacturing method described above, it is possible to obtain the wastewater treatment performance improver 5 that can more stably treat the wastewater to be treated in the biological treatment tank 12.

  In the above-described production method, in the mixture of the adapted sludge and the cationic flocculant, the aggregation of the mixture is promoted by the electrical action of the negatively charged adapted sludge and the cationic flocculant, and the size of the aggregate is reduced. growing. For this reason, in step S16 which spin-dry | dehydrates a mixture, a filter medium (for example, filter cloth) becomes difficult to block | close, and dehydration efficiency becomes favorable. Therefore, according to the manufacturing method described above, the wastewater treatment performance improver 5 can be efficiently manufactured.

Next, a wastewater treatment apparatus and a wastewater treatment method according to some embodiments will be described.
As described above, the wastewater treatment apparatus 1 (see FIG. 1) according to an embodiment is a wastewater treatment apparatus for treating the laundry wastewater 8, and includes a drainage tank 10, a biological treatment tank 12, and a treated water tank. 16. In the biological treatment tank 12, the laundry wastewater 8 from the drainage tank 10 is aerated and mixed with the activated sludge to which the above-described wastewater treatment performance improver 5 is added for biological treatment.

As shown in FIG. 1, the wastewater treatment apparatus 1 further includes a separation membrane 14 for filtering the treated wastewater biologically treated in the biological treatment tank 12. The treated wastewater filtered by the separation membrane 14 is stored in the treated water tank 16.
The separation membrane 14 may be provided inside the biological treatment tank 12. Alternatively, the separation membrane 14 may be provided between the biological treatment tank 12 and the treated water tank 16.

  Further, as shown in FIG. 1, the waste water treatment apparatus 1 has a COD (chemical oxygenation) of waste water in the biological treatment tank 12 as a detection unit for detecting the treatment performance of the laundry waste water 8 by activated sludge in the biological treatment tank 12. The COD measuring unit 13 for measuring the required amount is further provided. The wastewater treatment apparatus 1 further includes a supply unit 18 configured to add the wastewater treatment performance improver 5 to the biological treatment tank 12 based on the measurement result of the COD measurement unit 13.

The waste water treatment method according to some embodiments can be carried out by the waste water treatment apparatus 1 described above, in the step (S2) of adding the waste water treatment performance improver 5 described above to the sludge, and the biological treatment tank 12 And biologically treating the wastewater using the sludge to which the wastewater treatment performance improver 5 is added (S4).
Here, FIG.4 and FIG.5 is a flowchart of the waste water treatment method which concerns on one Embodiment, respectively.

  In the wastewater treatment method shown in the flowchart of FIG. 4, first, the wastewater treatment performance improver 5 is added to the sludge (S22 (corresponding to S2 described above)), and the sludge to which the wastewater treatment performance improver 5 is added in step S22. (S24). Then, biological treatment of the wastewater is performed using the sludge adapted in step S24 (sludge to which the wastewater treatment performance improver 5 is added) (S26 (corresponding to S4 described above)).

The wastewater treatment capacity improver 5 added to the acclimatized sludge contains a cationic flocculant supported on the freeze-dried sludge, so that the freeze-dried sludge is positively charged. Therefore, the negatively charged sludge (sludge floc) and electricity Easy to combine.
In the above-described wastewater treatment method, the sludge to which such a wastewater treatment performance improver 5 is added is adapted, so that the freeze-dried sludge is electrically coupled to sludge having a relatively large particle size (sludge floc). The freeze-dried sludge is less likely to flow out of the acclimatized culture tank. For this reason, acclimatization of sludge can be performed in a comparatively short period of time.
Further, in the above-described wastewater treatment method, biological treatment is performed using activated sludge obtained by acclimatizing the sludge to which the wastewater treatment performance improver 5 is added, so that the freeze-dried sludge has a relatively large particle size. It becomes easy to stay in the biological treatment tank by being electrically coupled to (sludge floc). For this reason, the wastewater to be treated can be more stably treated in the biological treatment tank.

In the wastewater treatment method described above, in step S22, the ratio of the amount of the wastewater treatment performance improver 5 added to the sludge to the amount of sludge (the amount of the wastewater treatment performance improver 5 added / the amount of sludge) is 1 in terms of MLSS. / 19 or more and 1/1 or less may be sufficient.
By making the ratio of the added amount of the wastewater treatment performance improver to the sludge to 1/19 or more in terms of MLSS, the sludge wastewater treatment performance can be effectively improved. Moreover, the outflow of freeze-dried sludge can be more effectively suppressed by setting the ratio of the added amount of the wastewater treatment performance improver to the sludge to 1/1 or less in terms of MLSS.

  In the wastewater treatment method shown in the flowchart of FIG. 5, the wastewater is biologically treated in the biological treatment tank 12 using the sludge to which the wastewater treatment performance improver 5 is added (S32 (corresponding to S4 described above)). And the wastewater treatment performance by the sludge in the biological treatment tank 12 is measured (S34), and when the measurement result shows that the wastewater treatment performance is lowered by the sludge (Yes in S36), the sludge in the biological treatment tank 12 The wastewater treatment performance improver 5 is added (S38 (corresponding to S2 described above)).

Since the wastewater treatment capacity improving agent 5 added to the sludge used for biological treatment in the biological treatment tank 12 contains the cationic flocculant supported on the freeze-dried sludge, the freeze-dried sludge is positively charged, and thus minus. Easy to electrically couple with charged sludge (sludge floc).
In the above-described wastewater treatment method, sludge to which such a wastewater treatment performance improver 5 is added is used for wastewater treatment, so that freeze-dried sludge is electrically coupled to sludge having a relatively large particle size (sludge floc). This makes it easier to stay in the biological treatment tank 12. For this reason, the wastewater to be treated can be more stably treated in the biological treatment tank 12.
Moreover, in the above-mentioned waste water treatment method, since the waste water treatment performance improver 5 is added to the sludge when the waste water treatment performance is reduced, the sludge waste water treatment performance can be recovered.

  In the above-described wastewater treatment method, when the wastewater treatment performance due to sludge in the biological treatment tank 12 is measured in step S34, no decrease in wastewater treatment performance due to sludge is detected in step S36 (No in S36). Then, the biological treatment of the wastewater by the sludge in the biological treatment tank 12 (S32) and the measurement of the treatment performance of the sludge in the biological treatment tank 12 (S34) are continued.

In one embodiment, the COD measurement unit 13 measures the COD (chemical oxygen demand) of the wastewater in the biological treatment tank 12 in step S34. In step S36, when the COD reduction rate measured by the COD measurement unit 13 is equal to or lower than the threshold value, it is determined that the wastewater treatment performance due to sludge is reduced (Yes in S36). May be.
Thus, based on the measurement result of the COD of the wastewater in the biological treatment tank 12, by appropriately adding the wastewater treatment performance improver 5 as necessary, while suppressing the addition amount of the wastewater treatment performance improver 5. The wastewater treatment performance by sludge can be recovered.

In the wastewater treatment method described above, in step S38, the ratio of the amount of the wastewater treatment performance improver 5 added to the sludge relative to the amount of sludge (the amount of the wastewater treatment performance improver 5 added / the amount of sludge) is 1 in terms of MLSS. / 19 or more and 1/1 or less may be sufficient.
By making the ratio of the added amount of the wastewater treatment performance improver to the sludge to 1/19 or more in terms of MLSS, the sludge wastewater treatment performance can be effectively improved. Moreover, the outflow of freeze-dried sludge can be more effectively suppressed by setting the ratio of the added amount of the wastewater treatment performance improver to the sludge to 1/1 or less in terms of MLSS.

In one embodiment, the wastewater treatment method may further perform a step of filtering the treated wastewater biologically treated using the sludge to which the wastewater treatment performance improver 5 is added in step S4 by membrane separation.
For example, in the wastewater treatment method shown in the flowchart of FIG. 4 or FIG. 5, step S4 (step S26 in FIG. 4 or step S4 in which wastewater is biologically treated in the biological treatment tank 12 using sludge to which the wastewater treatment performance improver 5 is added. The treated wastewater biologically treated in step S32 in FIG. 5 may be filtered by membrane separation using a separation membrane (filter) 14 (see FIG. 1).

  In this case, since the sludge to which the wastewater treatment performance improver 5 is added in the biological treatment of the wastewater is used, the sludge aggregation is promoted by the electrical action of the negatively charged sludge and the positively charged freeze-dried sludge. Agglomerate size increases. For this reason, in the process of filtering biologically treated wastewater by membrane separation, the filter used for membrane separation is less likely to be blocked, and the flow rate of treated wastewater that passes through the filter is unlikely to decrease. Therefore, the wastewater to be treated can be treated more efficiently.

  Next, the manufacture example of the wastewater treatment ability improving agent which concerns on one Embodiment and the test example which confirmed the effect using the manufactured wastewater treatment ability improvement agent are demonstrated.

(Manufacturing example of wastewater treatment capacity improver)
About 3.5 m ³ of acclimatized sludge having an MLSS of about 10,000 ppm obtained by acclimatizing the raw material sludge with laundry wastewater, and polydicyandiamide (1% (v / v) based on the raw material sludge) as a cationic flocculant Mixing to obtain a mixture of acclimatized sludge and polydicyandiamide.
Next, the above mixture was dehydrated using a filter cloth to obtain about 223 kg of dehydrated cake. The water content of this dehydrated cake was about 80%.
The obtained dehydrated cake was frozen in a freezer and then dried under reduced pressure in a vacuum dryer to obtain a wastewater treatment performance improver comprising freeze-dried sludge and a cationic flocculant supported on the freeze-dried sludge. The yield of the wastewater treatment capacity improver was about 37 kg.

(Test Example 1)
A wastewater treatment test was carried out using the wastewater treatment performance improver obtained in the above production example.
FIG. 6 is a diagram showing a configuration of a test apparatus for a wastewater treatment test used in this test example.
As shown in FIG. 6, the wastewater treatment test apparatus 50 includes an aeration tank 54 having an aeration unit 52 at the bottom, a settling tank 56 that communicates with the aeration tank 54 via a communication pipe 55 at the top, and simulated drainage (simulated laundry). A drainage supply unit 51 for supplying the drainage) 20 to the aeration tank 54.
A predetermined amount of simulated laundry drainage 20 is supplied from the drainage supply unit 51. Activated sludge 22 is placed in the aeration tank 54, oxygen (O ₂ ) is supplied from the bottom aeration unit 52, and the simulated laundry wastewater supplied from the drainage supply unit 51 and the activated sludge 22 are aerated and mixed. It has become so. The activated sludge 22 aerated and mixed in the aeration tank 54 moves to the sedimentation tank 56 through the communication pipe 55 and settles. On the other hand, the simulated laundry wastewater 20 aerated and mixed in the aeration tank 54 becomes the biologically treated treated wastewater 24 and is discharged from the upper part of the settling tank 56.

As the simulated laundry drainage 20, a mixture of NH ₄ Cl as an N component, KH ₂ PO ₄ as a P component, and a laundry detergent was used.

7 and 8 are graphs showing the results of a wastewater treatment test using the wastewater treatment test apparatus 50 described above. FIG. 7 shows the test results when the activated sludge 22 is a mixture of the sewage sludge mixed with the wastewater treatment improver obtained in the above production example in a ratio of 1: 9 in terms of MLSS. On the other hand, FIG. 8 shows the test results when only the wastewater treatment improver obtained in the above production example is used as the activated sludge 22.
7 and 8, the horizontal axis indicates the elapsed time, the left vertical axis indicates the COD volume load of the simulated laundry wastewater 20 and the COD concentration of the treated wastewater 24, and the right vertical axis indicates the COD removal rate (treatment rate). Indicates.

As shown in FIGS. 7 and 8, in the wastewater treatment test apparatus 50, simulated wastewater (100 ppm) was added in batches from the wastewater supply unit 51 to the aeration tank 54 (A1 in FIG. 7 and a1 in FIG. 8).
After the batch addition of simulated wastewater, the COD concentration of the treated wastewater decreased (B1 in FIG. 7 and b1 in FIG. 8), and the wastewater treatment performance improver produced in the above-described production example in each test was the wastewater treatment capacity. Therefore, continuous addition of simulated waste water (2.2 L / day) was started (B2 in FIG. 7 and b2 in FIG. 8). In each test, the changes in the treated wastewater (treated water) COD concentration and the COD removal rate were as follows.

  When the sewage sludge and the wastewater treatment performance improver according to the above production example are mixed and used as the activated sludge, the treated wastewater COD decreases after the continuous addition of simulated wastewater (B2) as shown in FIG. Continuing (B1 to C1), the COD removal rate reached 90% or more after about 4 days from the start of continuous addition of simulated waste water (B2) (C3). Here, in order to confirm the further treatment capacity of the wastewater treatment capacity improver, the treatment load of the simulated wastewater was increased. That is, the N component, the P component, and the laundry detergent component of the simulated waste water were increased and added to the aeration tank 54 (D2). Despite increasing the treatment load of the simulated waste water, the treated wastewater COD concentration hardly increased (D1), and the COD removal rate was maintained at 90% or more. Therefore, when the treatment load of the simulated waste water was further increased (E2), the treated wastewater COD concentration was hardly increased and the COD removal rate was maintained at 90% or more. In addition, the treatment load of the simulated waste water added from the time of E2 is a thing equivalent to the load of the actual laundry waste water.

On the other hand, when only the wastewater treatment performance improver according to the above production example is used as the activated sludge, the treated wastewater COD concentration gradually increases after the start of continuous addition of simulated wastewater (b2) as shown in FIG. , About 4 days after the start of continuous addition of simulated waste water (b2), it began to decrease. However, even after about 16 days from the start of continuous addition of simulated waste water (b2), the increase in COD removal rate was limited to about 60% (d3).
That is, in the test using only the wastewater treatment performance improver according to the above-mentioned production example as the activated sludge, it does not increase the treatment load of the wastewater during the test period, and the load is lower than the load of the actual laundry wastewater. Even waste water could not be treated sufficiently.

  From the above results, when only the wastewater treatment performance improving agent according to the above production example is used as activated sludge, as shown in FIG. 8, a sufficient COD removal rate cannot be obtained in a period of about 16 days. It was. This is because the wastewater treatment performance improver according to the above-mentioned production example is positively charged, and the wastewater treatment performance improvers are electrically repelled to each other so that they are difficult to agglomerate, so that they stay in the aeration tank 54. This is considered to be because it tends to flow out from the aeration tank 54 to the outside of the settling tank 56 and the waste water treatment test apparatus 50 together with the treated waste water.

On the other hand, when the sewage sludge and the wastewater treatment performance improver according to the above production example are mixed and used, the wastewater treatment rate (COD removal rate) can be obtained in a relatively short time as shown in FIG. Excellent treatment capacity can be demonstrated even for a large amount of simulated wastewater (simulated wastewater with high concentrations of N component, P component and detergent component). This is because the negatively charged sewage sludge and the positively charged wastewater treatment performance improver are electrically coupled and are likely to stay in the aeration tank 54. Therefore, the simulated wastewater can be stabilized even in continuous water flow. It is thought that it was possible to process.
Therefore, by adding the wastewater treatment performance improver according to the production example to the sewage sludge and making it an activated sludge, the sludge can be acclimatized in a relatively short period of time, and excellent wastewater treatment performance can be obtained. It has been shown.

(Test Example 2)
As the activated sludge, the activated sludge A obtained by mixing the wastewater treatment improver obtained in the above-mentioned production example with sewage sludge in a ratio of 1: 1, 1: 3 and 1: 9, respectively, in terms of MLSS. Using activated sludge B and activated sludge C, the difference in the wastewater treatment performance due to the difference in the ratio of the added amount of the wastewater treatment capacity improver to the sludge was confirmed.
Using an acclimatization device (not shown), simulated laundry wastewater was added to each activated sludge (activated sludge A to C) so that the COD concentration increased by 50 ppm, and the COD concentration was measured. The graph of FIG. 9 shows the relationship between the elapsed time from the simulated laundry drainage input and the COD concentration.

As shown in FIG. 9, after the simulated laundry wastewater is added, the COD concentration is lowered after the temporary rise, so that it can be confirmed that the wastewater treatment capacity is exhibited in each of the activated sludges A to C. It was.
Moreover, the activated sludge is more activated sludge C (mixing ratio 1: 9) in the time range T1 in the vicinity where the COD concentration temporarily rises after the simulated laundry drainage is charged and then starts to decrease. About 58% larger than A (mixing ratio 1: 1) and about 36% larger than activated sludge B (mixing ratio 1: 3). Therefore, it was confirmed that the activated sludge C may exhibit better wastewater treatment performance than the activated sludge A and the activated sludge B.

(Test Example 3)
As the activated sludge, the wastewater treatment improver obtained in the above-mentioned production example is mixed with the activated sludge D obtained by mixing the sewage sludge at a ratio of 1: 9 in the ratio of 1: 9 in terms of MLSS. Using the activated sludge E obtained in this way, the difference in the wastewater treatment performance due to the difference in the ratio of the added amount of the wastewater treatment performance improver to the sludge was confirmed.
Using an acclimatization device (not shown), simulated laundry drainage was introduced to each activated sludge (activated sludge D and activated sludge E) so that the initial COD concentration was 100 ppm, and the COD concentration was measured. The relationship between the elapsed time from the simulated laundry drainage input and the COD concentration is shown in the graph of FIG.

As shown in FIG. 10, since the COD concentration was lowered after the simulated laundry wastewater was added, it was confirmed that the wastewater treatment capacity was exhibited in both the activated sludge D and the activated sludge E.
In addition, the activated sludge E (mixing ratio 1:19) is more effective for the activated sludge D (mixing ratio 1: 9) in the time range T2 in the vicinity of the start of the decrease in the COD concentration after the simulated laundry drainage is charged. ) About 170% larger. Therefore, it was confirmed that the activated sludge D may exhibit better wastewater treatment performance than the activated sludge E.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, The form which added the deformation | transformation to embodiment mentioned above and the form which combined these forms suitably are included.

In this specification, an expression representing a relative or absolute arrangement such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial”. Represents not only such an arrangement strictly but also a state of relative displacement with tolerance or an angle or a distance to obtain the same function.
For example, an expression indicating that things such as “identical”, “equal”, and “homogeneous” are in an equal state not only represents an exactly equal state, but also has a tolerance or a difference that can provide the same function. It also represents the existing state.
In this specification, expressions representing shapes such as quadrangular shapes and cylindrical shapes not only represent shapes such as quadrangular shapes and cylindrical shapes in a strict geometric sense, but also within a range where the same effects can be obtained. In addition, a shape including an uneven portion or a chamfered portion is also expressed.
In this specification, the expression “comprising”, “including”, or “having” one constituent element is not an exclusive expression for excluding the existence of another constituent element.

DESCRIPTION OF SYMBOLS 1 Waste water treatment equipment 2 Sludge floc 4 Freeze-dried sludge 5 Waste water treatment performance improver 8 Laundry waste water 10 Waste water tank 12 Biological treatment tank 13 COD measurement part 14 Separation membrane 16 Treated water tank 18 Supply part 20 Simulated laundry waste water 22 Activated sludge 24 treatment Wastewater 50 Wastewater treatment test equipment 51 Wastewater supply part 52 Aeration part 54 Aeration tank 55 Communication pipe 56 Settling tank

Claims (14)

A wastewater treatment performance improver for improving sludge wastewater treatment performance,
Freeze-dried sludge containing familiar sludge,
A cationic flocculant supported on the freeze-dried sludge;
A wastewater treatment performance improver characterized by comprising:   The wastewater treatment capacity improver according to claim 1, wherein the cationic flocculant contains a cationic polymer.   The wastewater treatment performance improver according to claim 2, wherein the cationic polymer includes a polydicyandiamide-based polymer. Acclimatize sludge and get the familiar sludge;
Mixing the acclimatized sludge and the cationic flocculant to obtain a mixture;
Lyophilizing the mixture to obtain a wastewater treatment performance improver;
A method for producing a wastewater treatment capacity improver characterized by comprising: Further comprising dehydrating the mixture to obtain a dehydrated cake;
The method for producing a wastewater treatment performance improver according to claim 4, wherein in the step of obtaining the wastewater treatment performance improver, the dewatered cake is freeze-dried. Adding the wastewater treatment performance improver according to any one of claims 1 to 3 to sludge;
Biologically treating the wastewater using the sludge to which the wastewater treatment performance improver has been added;
A wastewater treatment method comprising:   The wastewater treatment method according to claim 6, further comprising a step of adapting the sludge to which the wastewater treatment performance improver is added.   The wastewater treatment apparatus according to claim 6 or 7, wherein in the step of adding the wastewater treatment performance improver, the wastewater treatment performance improver is added to the sludge when the treatment performance of the wastewater is reduced by the sludge. Processing method.   The ratio of the addition amount of the wastewater treatment performance improver to the sludge with respect to the sludge amount (addition amount of the wastewater treatment performance improver / amount of the sludge) is 1/19 or more and 1/1 or less in terms of MLSS. The wastewater treatment method according to any one of claims 6 to 8, wherein the wastewater treatment method is provided.   The wastewater treatment method according to any one of claims 6 to 9, further comprising a step of filtering the biologically treated wastewater by membrane separation. A drainage tank for storing wastewater to be treated;
A biological treatment tank for subjecting the wastewater from the wastewater tank to a biological treatment by aeration mixing with the activated sludge to which the wastewater treatment performance improving agent according to any one of claims 1 to 3 is added;
A treated water tank for storing treated wastewater treated in the biological treatment tank;
A wastewater treatment apparatus comprising: Further comprising a separation membrane for filtering the treated waste water,
The wastewater treatment apparatus according to claim 11, wherein the treated water tank is configured to store the treated wastewater filtered by the separation membrane. A detection unit for detecting wastewater treatment performance in the biological treatment tank;
Based on the detection result by the detection unit, a supply unit configured to further add the wastewater treatment capacity improver to the biological treatment tank,
The wastewater treatment apparatus according to claim 11 or 12, further comprising:   The waste water treatment apparatus according to claim 13, wherein the detection unit includes a COD measurement unit for measuring the COD of the waste water in the biological treatment tank.

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