JP2021186799A - Wastewater treatment system and wastewater treatment method - Google Patents

Abstract

To provide a wastewater treatment system which enables continuous reception and stable treated water discharge even for wastewater with a large discharge amount and a large pollution concentration variation.SOLUTION: A wastewater treatment system with batch-type flocculation settling tanks comprises at least two batch-type flocculation settling tanks to receive single or multiple supplies of water to be treated. The at least two batch-type flocculation settling tanks are connected in parallel for the single or multiple supplies of water to be treated. In each of the at least two batch-type flocculation settling tank, the wastewater treatment system receives the water to be treated, performs flocculation settling treatment of the received water to be treated, and discharges a product of the flocculation settling treatment, where the at least two batch-type flocculation settling tanks sequentially receive the water to be treated.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a wastewater treatment system and a wastewater treatment method for wastewater from a corrugated board manufacturing factory or the like.

At the corrugated board manufacturing factory, glue cleaning water derived from the laminating machine and ink cleaning water derived from the box making machine are generated as wastewater. It is necessary to treat these so that the treated water quality and waste are suitable for the Water Pollution Control Law and the Waste Management Law. Since these wastewaters are wash water, it is difficult to obtain stable treated water quality due to large load fluctuations such as fluctuations in the frequency of occurrence, the amount of generation, and the pollution concentration.

As a device for responding to load fluctuations of water to be treated, a batch type coagulation sedimentation treatment device that adjusts the chemical addition method, stirring method, precipitation time, etc. according to the load amount of the water quality to be treated by using the primary treatment as a batch method is widely used. It has been introduced. However, since it is a batch method, a large adjustment tank that can store about one day's worth of wastewater is required in front of the batch type coagulation and sedimentation treatment device, and the batch type coagulation and sedimentation treatment device itself also collects one day's worth. There is a demerit that it becomes large because it needs to be processed.
Patent Document 1 describes that anaerobic treated water is continuously treated in two batch type treatment tanks in order to make the facility compact.
On the other hand, Patent Document 2 describes a technique for providing a seemingly continuous and stable mixed liquid by mixing two kinds of raw materials in two batch type mixing tanks provided in parallel.

Japanese Unexamined Patent Publication No. 03-047599 Japanese Unexamined Patent Publication No. 2019-118904

However, Patent Document 1 is intended for receiving anaerobic treated water, and requires a storage tank for inflow water in front of the anaerobic treated tank, which is insufficient in terms of space saving.
Further, also in Patent Document 2, since a storage tank for raw materials is required in front of each mixing tank, it is insufficient in terms of space saving.
In addition, since the treated water discharge of the batch type coagulation sedimentation treatment device is intermittent, if a biological treatment device that is ideally operated with a constant load is installed in the subsequent stage, another adjustment tank for the biological treatment device is required. You will need it. Since the increase in the total number and volume of adjustment tanks greatly affects the installation area, it is a major obstacle to the operation of corrugated board manufacturing factories that are located in relatively urban areas and often have site restrictions.
The present disclosure provides a wastewater treatment system and a wastewater treatment method that enable continuous reception and stable discharge of treated water even for wastewater having large fluctuations in the amount of discharged water and the pollution concentration.

[1] A wastewater treatment system equipped with a batch type coagulation settling tank.
The wastewater treatment system comprises at least two batch coagulation sedimentation tanks that receive one or more water to be treated.
The at least two batch coagulation sedimentation tanks are connected in parallel to the supply of the single or multiple treated waters.
The wastewater treatment system receives the water to be treated, performs the coagulation sedimentation treatment of the received water to be treated, and discharges the treated product by the coagulation sedimentation treatment in each of the at least two batch type coagulation sedimentation tanks.
A wastewater treatment system comprising continuously and sequentially receiving the water to be treated into the at least two batch coagulation and settling tanks.
[2] The at least two batch coagulation settling tanks have two batch coagulation settling tanks.
When the wastewater treatment system is performing the coagulation-sedimentation treatment of the water to be treated and the discharge of the treated product by the coagulation-sedimentation treatment in one of the two batch-type coagulation-sedimentation tanks, the two batch-type coagulation / sedimentation tanks are performed. On the other side of the settling tank, the water to be treated is received,
The wastewater treatment system according to [1], wherein the water to be treated is continuously and alternately received into the two batch type coagulation sedimentation tanks.
[3] The at least two batch type coagulation and settling tanks have three batch type coagulation and settling tanks.
The water to be treated is continuously and sequentially received into the three batch coagulation and settling tanks.
The wastewater treatment system according to [1], wherein the treated matter is continuously discharged in order by the coagulation-sedimentation treatment in the three batch-type coagulation-sedimentation tanks.
[4] The at least two batch type coagulation and settling tanks are provided with a chemical addition device and a stirrer for adding a coagulant to each of the at least two batch type coagulation and settling tanks.
The wastewater treatment system according to any one of [1] to [3], wherein the coagulant is added by the chemical addition device in the coagulation sedimentation treatment.
[5] The wastewater treatment system includes a measuring instrument for measuring the water to be treated.
The measuring instrument has an electric conductivity meter for measuring the electric conductivity of the water to be treated.
The relationship between the electric conductivity prepared in advance and the amount of the agglutinating agent added based on the electric conductivity of the water to be treated received by the wastewater treatment system in each of the at least two batch type agglutination and settling tanks. It has a chemical amount calculation unit that determines the amount of coagulant added by the formula.
The wastewater treatment system according to [4], wherein in the coagulation-sedimentation treatment, the coagulant is added to the water to be treated by the chemical addition device at the amount of the coagulant added.
[6] The wastewater treatment system according to [5], wherein the measuring instrument comprises a flow meter for measuring the inflow of the water to be treated into the at least two batch coagulation sedimentation tanks.
[7] The chemical amount calculation unit
The electric conductivity of the water to be treated is calculated from the indicated values of the flow meter and the electric conductivity meter, and the amount of the flocculant added is determined by the relational expression.
The wastewater treatment system according to [6], which outputs the determined addition amount of the flocculant to the chemical addition device.
[8] The wastewater treatment system measures the inflow of the water to be treated into the at least two batch coagulation and settling tanks, and the water to be treated into the at least two batch coagulation and settling tanks. Equipped with a flow path control device, which switches acceptance,
The wastewater treatment system according to any one of [1] to [7], wherein the flow rate control device switches the acceptance of the water to be treated by using the indicated value of the flow meter as an input.
[9] The wastewater treatment system according to any one of [1] to [8], wherein the single or a plurality of treated waters are wastewater generated in a corrugated cardboard factory.
[10] The wastewater treatment system includes a biological treatment tank for biologically treating the treated water of the at least two batch coagulation sedimentation tanks after the at least two batch coagulation sedimentation tanks [1]. The wastewater treatment system according to any one of [9].
[11] The wastewater treatment system according to [10], wherein the biological treatment tank is a membrane separation activated sludge treatment device.
[12] The wastewater according to any one of [1] to [11], which is provided with a dehydration facility for solid-liquid separation of the precipitates of the at least two batch coagulation sedimentation tanks after the at least two batch coagulation sedimentation tanks. Processing system.
[13] The wastewater treatment system according to [12], wherein the dehydration facility has a filter press dehydrator.
[14] A wastewater treatment method using a wastewater treatment system equipped with a batch type coagulation settling tank.
The wastewater treatment system comprises at least two batch coagulation sedimentation tanks that receive one or more water to be treated.
The at least two batch coagulation sedimentation tanks are connected in parallel to the supply of the single or multiple treated waters.
The wastewater treatment method is
In each of the at least two batch type coagulation-sedimentation tanks, the receiving step of receiving the water to be treated, the coagulation-sedimentation treatment step of performing the coagulation-precipitation treatment of the received water to be treated, and the treated product by the coagulation-sedimentation treatment step are discharged. Has a discharge process,
A wastewater treatment method in which the receiving steps are continuously performed in sequence in the at least two batch type coagulation and settling tanks.

INDUSTRIAL APPLICABILITY According to the present disclosure, it is possible to provide a wastewater treatment system and a wastewater treatment method that enable continuous reception and stable discharge of treated water even for wastewater having large fluctuations in the amount of discharged water and the pollution concentration.

Basic form of wastewater treatment system Basic form of wastewater treatment system Wastewater treatment system of the first embodiment Wastewater treatment system of the second embodiment Examples of multiple water lines

(Basic form 1)
First, the basic form of the wastewater treatment system will be described with reference to the drawings.
The wastewater treatment system 100 shown in FIG. 1 is an example of a continuous system. The wastewater treatment system 100 includes a first adjusting tank 11, a second adjusting tank 12, a first chemical mixing tank 13, a second chemical mixing tank 14, a settling tank 15, a biological treatment tank 7, and a dehydration facility 4. .. The arrow connecting each tank in the figure indicates the flow of water (treated water, treated water) or sludge by a water supply line or the like.

The first adjusting tank 11 and the second adjusting tank 12 are connected in parallel, and different wastewaters are sent from a water supply line (not shown). For example, in a corrugated cardboard manufacturing factory, glue cleaning water and ink cleaning water are sent, respectively.
The water to be treated in the first adjusting tank 11 and the second adjusting tank 12 is first sent to the first chemical mixing tank 13. In the first chemical mixing tank 13, for example, an inorganic flocculant is added to agglomerate fine particles. A pH adjuster such as an alkaline agent may be added to control the pH to be suitable for agglutination.

The agglutinated water to be treated in the first chemical mixing tank 13 is sent to the subsequent second chemical mixing tank 14. In the second chemical mixing tank 14, for example, a polymer flocculant is added to floc the aggregated fine particles and facilitate precipitation.
The water to be treated that has passed through the second chemical mixing tank 14 is then sent to the settling tank 15. In the settling tank 15, the water to be treated is allowed to stand for a predetermined time, and the water to be treated is separated into a supernatant liquid and a sludge slurry containing flocs.
The supernatant liquid is sent to the biological treatment tank 7, treated biologically, and then discharged as treated water. Biological treatment includes activated sludge treatment and the like. On the other hand, the sludge slurry containing flocs is sent to the dehydration facility 4, subjected to solid-liquid separation, and then discharged as dehydrated sludge.

(Basic form 2)
Next, the basic form of the wastewater treatment system will be described by taking a batch method as an example.
The wastewater treatment system 100 shown in FIG. 2 includes a first adjustment tank 11, a second adjustment tank 12, a chemical mixing and settling tank 16, a biological treatment adjustment tank 17, a biological treatment tank 7, and a dehydration facility 4. The arrow connecting each tank in the figure indicates the flow of water (treated water, treated water) or sludge by a water supply line or the like.

The first adjusting tank 11 and the second adjusting tank 12 are the same as those in FIG. The water to be treated in the first adjusting tank 11 and the second adjusting tank 12 is first sent to the chemical mixing and settling tank 16. In the chemical mixing and settling tank 16, chemicals such as a flocculant are mixed and flocs are settled in a batch manner.
In the chemical mixing settling tank 16, first, an inorganic flocculant and, if necessary, a pH adjuster such as an alkaline agent are added to the water to be treated to aggregate fine particles in the water to be treated. Next, a polymer flocculant is added to the water to be treated to floc the aggregated fine particles. Then, the water to be treated is allowed to stand for a predetermined time, and the water to be treated is separated into a supernatant liquid and a sludge slurry containing flocs.

The supernatant liquid is sent to the biological treatment adjusting tank 17. The biological treatment adjusting tank 17 plays a role of temporarily storing the entire amount of treated water discharged from the batch type chemical mixing and settling tank 16 at a time, and keeping the amount of water and the concentration of organic substances supplied to the subsequent biological treatment tank 7 constant. The water to be treated prepared in the biological treatment adjusting tank 17 is sent to the biological treatment tank 7, biologically treated, and then discharged as treated water.
On the other hand, the sludge slurry containing flocs is sent to the dehydration facility 4, subjected to solid-liquid separation, and then discharged as dehydrated sludge.

(First embodiment)
The present disclosure relates to a wastewater treatment system comprising in parallel at least two batch coagulation settling tanks that receive one or more water to be treated. Hereinafter, the wastewater treatment system of the present disclosure will be described with reference to the drawings.
FIG. 3 relates to the wastewater treatment system of the first embodiment. The wastewater treatment system 100 includes, as at least two batch-type coagulation and settling tanks, a batch-type coagulation and settling tank 1 that accepts a single or a plurality of waters to be treated and a batch-type coagulation and settling tank 2 that accepts a single or a plurality of batches of water to be treated. Be prepared. In FIG. 3, the number of batch type coagulation sedimentation tanks is two, but it may be three, three or more, or four or more. The number of batch coagulation settling tanks is, for example, preferably 2 to 6, more preferably 2 to 4, and even more preferably 2 or 3.
The wastewater treatment system may also be provided with a biological treatment tank 7 and a dehydration facility 4 downstream following at least two batch coagulation and settling tanks, as shown in FIG. The arrow (solid line or broken line) connecting each tank in the figure indicates the flow of water (treated water, treated water) or sludge slurry by a water supply line or the like.

At least two batch coagulation settling tanks (eg, batch coagulation settling tank 1 and batch coagulation settling tank 2) are connected in parallel to a single or multiple feeds of water to be treated.
For example, the batch type coagulation settling tank 1 is connected to a supply line A1 to which the first water to be treated is supplied and a supply line A2 to which the second water to be treated is supplied. Further, a supply line B1 to which the first water to be treated is supplied and a supply line B2 to which the second water to be treated is supplied are connected to the batch type coagulation settling tank 2.
Further, the flow of the water to be treated to the supply lines A1 and B1 for supplying the first water to be treated to each coagulation and settling tank can be switched by, for example, a flow path switching valve 5. The flow of the water to be treated to the supply lines A2 and B2 for supplying the second water to be treated to each settling tank can also be switched by, for example, the flow path switching valve 5.

Even if the wastewater treatment system includes a flow path control device 6 that switches the receiving destination of the water to be treated by at least two batch coagulation sedimentation tanks (for example, a batch coagulation sedimentation tank 1 and a batch coagulation sedimentation tank 2). good. By controlling the flow path switching valve 5, for example, the flow path control device 6 switches the flow of the water to be treated between the supply lines A1 and B1 and the flow of the water to be treated between the supply lines A2 and B2. It can be performed.
When one or more waters to be treated are wastewater from a corrugated cardboard factory, for example, the first water to be treated is glue wash water and the second water to be treated is ink wash water.

Although the first water to be treated and the second water to be treated are shown in FIG. 3, the water to be treated may be single. That is, the water to be treated may be only the first water to be treated. Further, the water to be treated may further include a third water to be treated, a fourth water to be treated ... nth water to be treated.
In this case, supply lines An and Bn for supplying the nth water to be treated are connected to at least two batch type coagulation and settling tanks (batch type coagulation and settling tank 1 and batch type coagulation and settling tank 2, respectively). At least two batch coagulation settling tanks (for example, batch coagulation settling tank 1 and batch coagulation settling tank 2) have a first water to be treated, a second water to be treated ... nth to be treated, respectively. Can accept water.

In the wastewater treatment system 100, in each of at least two batch type coagulation sedimentation tanks, the water to be treated is received, and the treated product is discharged by the coagulation sedimentation treatment and the coagulation sedimentation treatment of the received water to be treated. Receipt of water to be treated, coagulation sedimentation treatment and discharge of treated material are repeated.
Then, the water to be treated is sequentially received into at least two batch coagulation sedimentation tanks.

In at least two batch type coagulation and sedimentation tanks (for example, batch type coagulation and sedimentation tank 1 and batch type coagulation and sedimentation tank 2), the coagulation and sedimentation treatment of the water to be treated is performed by the batch type (batch type) (coagulation and sedimentation step). In the coagulation-precipitation treatment, first, an inorganic coagulant is added to the water to be treated (inorganic coagulation step). By adding the inorganic flocculant, the fine particles in the water to be treated are aggregated.
The inorganic flocculant is not particularly limited, and a known inorganic flocculant can be used. For example, aluminum sulfate, polyaluminum chloride, ferric chloride, ferrous sulfate, polyferric sulfate and the like can be mentioned.

The amount of the inorganic flocculant added to the water to be treated is preferably about 5 mg / L to 1000 mg / L, more preferably about 10 mg / L to 500 mg / L in terms of solid amount such as alumina or iron.
A pH adjuster such as a known acid or alkaline agent may be added to control the pH to be suitable for aggregation. In the coagulation-precipitation treatment, an inorganic coagulant and an alkaline agent are preferably added.
In the case of an aluminum-based flocculant, the pH at the time of aggregation is preferably about 5.0 to 8.0, more preferably about 6.0 to 7.5, and even more preferably about 6.5 to 7.0. You just have to control it. In the case of an iron-based flocculant, the pH may be preferably controlled to 4.0 or more, more preferably about 6.5 to 7.0.

Subsequently, the polymer flocculant is added to the water to be treated to which the inorganic flocculant has been added (polymer coagulation step). The polymer flocculant further aggregates the aggregates of fine particles aggregated by the inorganic flocculant to form large flocs (flocking). Since the formed flocs are easily settled, solid-liquid separation is easy.
The polymer flocculant is not particularly limited, and a known polymer flocculant can be used. For example, polyacrylamide-based, 2-acrylloylamino-2-methylpropanesulfonic acid (AMPS) and the like can be mentioned. Examples of the polymer flocculant include an anionic polymer flocculant, a cationic polymer flocculant, and a nonionic polymer flocculant, which may be appropriately selected depending on the charged state of the water to be treated.
The amount of the polymer flocculant added to the water to be treated is preferably about 0.1 mg / L to 5.0 mg / L, more preferably 0.5 mg / L to 2.0 mg / L in terms of solid amount. Degree.

In order to enhance the agglutination effect of the inorganic agglutinating agent and the polymer agglutinating agent and to complete the agglutination treatment quickly, at least two batch-type agglutination-sedimentation tanks (for example, a batch-type agglutination-sedimentation tank 1 and a batch-type agglutination-sedimentation tank 2). Is preferably provided with a stirring device 23 and a chemical addition device 22. In the coagulation / precipitation treatment in each coagulation / sedimentation tank, the chemical addition device 22 adds a coagulant (inorganic coagulant and polymer coagulant) and, if necessary, a pH adjuster to each of at least two batch type coagulation / sedimentation tanks. ..
The chemical addition device 22 can automatically control the addition of the inorganic flocculant, the polymer flocculant and the pH adjuster.

The water to be treated (treated product by coagulation-precipitation treatment) to which a polymer flocculant is added and flocs are formed is allowed to stand for a predetermined time by, for example, sedimentation separation, and a precipitate containing a supernatant liquid (treated water) and flocs (treated product). It is separated into sludge slurry) (sedimentation step).
The supernatant liquid (treated water) in the batch type coagulation sedimentation tank 1 is sent to the biological treatment tank 7 by the water supply line C1. Further, the supernatant liquid (treated water) in the batch type coagulation sedimentation tank 2 is sent to the biological treatment tank 7 by the water supply line D1.
On the other hand, the precipitate containing flocs (sludge slurry) in the batch type coagulation settling tank 1 is drawn out by the sludge take-out line C2 and sent to the dehydration facility 4. Further, the sediment (sludge slurry) containing the flocs of the batch type coagulation sedimentation tank 2 is drawn out by the sludge take-out line D2 and sent to the dehydration facility 4.
Although the water supply lines C1 and D1 are drawn as separate lines in the figure, they may be merged in front of the biological treatment tank 7. Similarly, the sludge removal lines C2 and D2 may be merged in front of the dewatering equipment 4.

The at least two batch coagulation and settling tanks preferably have two batch coagulation and settling tanks. Moreover, it is preferable that at least two batch type coagulation and settling tanks are two batch type coagulation and settling tanks.
In the wastewater treatment system 100, when there are two batch type coagulation and settling tanks as shown in FIG. 3, one of the two batch type coagulation and settling tanks (batch type coagulation and settling tank 1 and batch type coagulation and settling tank 2) is to be treated. When the coagulation sedimentation treatment of water and the discharge of the treated product of the coagulation sedimentation treatment are performed, the other one of the two batch type coagulation sedimentation tanks (the batch type coagulation sedimentation tank 1 and the batch type coagulation sedimentation tank 2). Accepts the water to be treated. Then, the water to be treated is continuously and alternately received into the two batch type coagulation and settling tanks. That is, the water to be treated is received in the batch type coagulation and settling tank 1 and the water to be treated is received in the batch type coagulation and settling tank 2 alternately.
While the batch type coagulation and sedimentation tank 1 receives the first water to be treated and the second water to be treated by the supply lines A1 and A2, the batch type coagulation and sedimentation tank 2 performs the coagulation and sedimentation treatment of the water to be treated. Will be. When the coagulation sedimentation treatment in the batch type coagulation sedimentation tank 2 is completed, the supernatant liquid (treated water) is sent to the biological treatment tank 7 by the water supply line D1, and the sediment (sludge slurry) is sent to the dehydration facility 4 by the sludge removal line D2. Sent.
When the supernatant liquid and the precipitate (sludge slurry) are discharged, the supply lines of the first water to be treated and the second water to be treated are switched from A1 and A2 to B1 and B2. Then, the supply lines B1 and B2 start accepting the first water to be treated and the second water to be treated in the batch type coagulation settling tank 2.
On the other hand, in the batch type coagulation sedimentation tank 1, the coagulation sedimentation treatment of the water to be treated is performed. When the coagulation sedimentation treatment in the batch type coagulation sedimentation tank 1 is completed, the supernatant liquid is sent to the biological treatment tank 7 by the water supply line C1, and the sediment (sludge slurry) is sent to the dehydration equipment 4 by the sludge removal line C2.
When the supernatant liquid and the precipitate (sludge slurry) are discharged, the supply lines of the first water to be treated and the second water to be treated are switched from B1 and B2 to A1 and A2, and the batch type coagulation sedimentation tank 1 is used. The water to be treated is received at. These operations are repeated in the wastewater treatment system.

In this way, the batch type coagulation and settling tank 1 and the batch type coagulation and settling tank 2 alternately receive one or a plurality of waters to be treated. As a result, the water to be treated can be continuously received at all times, and one of the coagulation and settling tanks can also serve as the adjusting tank. Therefore, the first adjusting tank 11 and the second adjusting tank 12 described above can be used. There is no need for an adjustment tank such as. Further, although the coagulation sedimentation treatment is a batch type, it is possible to continuously receive the water to be treated, so that the size of the coagulation sedimentation tank can be made compact.
Further, since the treatments are alternately performed in the two coagulation sedimentation tanks, the discharge of the treated water can be made pseudo-continuous. Therefore, when the biological treatment tank 7 is provided downstream of the batch type coagulation and settling tank, the amount of water supplied to the biological treatment tank 7 can be controlled at a flow rate close to a constant flow rate, so that the biological treatment adjustment tank 17 becomes unnecessary.
It is preferable that the wastewater treatment system 100 does not have a regulating tank on the upstream side of at least two batch type coagulation and settling tanks (for example, batch type coagulation and settling tank 1 and batch type coagulation and settling tank 2).

It is also a preferred embodiment that at least two batch coagulation settling tanks have three batch coagulation settling tanks or three batch coagulation settling tanks.
That is, the wastewater treatment system may include a batch type coagulation and settling tank 3 in addition to the batch type coagulation and settling tank 1 and the batch type coagulation and settling tank 2. The batch type coagulation settling tank 3 may have the same configuration as the batch type coagulation settling tank 1 and the batch type coagulation settling tank 2. The batch type coagulation and settling tank 3 is provided with, for example, a supply line according to the number of water to be treated, a water supply line for the treated water, a sludge take-out line, and the like in the same manner as the batch type coagulation and settling tank 1 and the batch type coagulation and settling tank 2. be able to.
The three batch coagulation settling tanks are connected in parallel to a single or multiple feeds of water to be treated. That is, each of the three batch type coagulation and settling tanks can receive the first water to be treated, the second water to be treated, and the nth water to be treated. Then, the wastewater treatment system sequentially and continuously receives the water to be treated into the three batch type coagulation and settling tanks.
Further, the water supply line and the sludge take-out line of each of the three batch type coagulation and settling tanks are connected to the biological treatment tank 7. The wastewater treatment system continuously and sequentially discharges the treated material by the coagulation sedimentation treatment in the three batch type coagulation sedimentation tanks.

For example, when the batch type coagulation and settling tank 1 is receiving the water to be treated, the batch type coagulation and settling tank 2 is used to perform the coagulation and sedimentation treatment of the water to be treated, and the batch type coagulation and settling tank 3 is used to perform the coagulation and sedimentation treatment. Discharge. After the coagulation sedimentation treatment in the batch coagulation sedimentation tank 2 and the discharge in the batch coagulation sedimentation tank 3 are completed, the acceptance of the water to be treated is switched from the batch coagulation sedimentation tank 1 to the batch coagulation sedimentation tank 3.
Then, the batch type coagulation sedimentation tank 1 performs the coagulation sedimentation treatment of the water to be treated, the batch type coagulation sedimentation tank 2 discharges the treated product of the coagulation sedimentation treatment, and the batch type coagulation sedimentation tank 3 receives the water to be treated. conduct. After the coagulation sedimentation treatment in the batch coagulation sedimentation tank 1 and the discharge in the batch coagulation sedimentation tank 2 are completed, similarly, the acceptance of the water to be treated is switched from the batch coagulation sedimentation tank 3 to the batch coagulation sedimentation tank 2.
Then, the batch type coagulation sedimentation tank 3 performs the coagulation sedimentation treatment of the water to be treated, the batch type coagulation sedimentation tank 1 discharges the treated product of the coagulation sedimentation treatment, and the batch type coagulation sedimentation tank 2 receives the water to be treated. conduct. Similarly, when the coagulation-sedimentation treatment and the discharge of the treated product are completed, the acceptance of the water to be treated is switched from the batch-type coagulation-sedimentation tank 2 to the batch-type coagulation-sedimentation tank 1. Then, the batch type coagulation and settling tank 1 receives the water to be treated, the batch type coagulation and settling tank 2 performs the coagulation and settling treatment, and the batch type coagulation and settling tank 3 discharges the treated product. This operation is repeated in the wastewater treatment system.

As described above, since at least two batch type coagulation and settling tanks have three batch type coagulation and settling tanks, both the reception of the water to be treated and the discharge of the treated water can be continuously performed. The same applies even if at least two batch coagulation sedimentation tanks are four or more batch coagulation sedimentation tanks. It becomes easy to control the amount of water supplied to the biological treatment tank 7 at a constant flow rate.

Further, by converting at least two batch type coagulation and settling tanks into three or more or four or more (or three or four) batch type coagulation and settling tanks, the following wastewater treatment can be performed.
In two batch coagulation settling tanks out of three or more batch coagulation settling tanks
When one of the two batch type coagulation sedimentation tanks is performing the coagulation sedimentation treatment of the water to be treated and the discharged product by the coagulation sedimentation treatment, the other one of the two batch type coagulation sedimentation tanks. The water to be treated is received, and the water to be treated is continuously and alternately received into the two batch coagulation sedimentation tanks.
Then, among the three or more batch type coagulation and settling tanks, in the batch type coagulation and settling tanks other than the two batch type coagulation and settling tanks, unsteady wastewater having a high concentration such as in-process blow drainage before the long-term shutdown of the factory can be used. Accepts abnormal wastewater in case of trouble independently and performs coagulation sedimentation treatment. After that, the processed product is discharged to the biological treatment tank 7 or the dehydration facility 4 in the subsequent stage while controlling the flow rate and the discharge time while considering the concentration of the treated product and the like.

Alternatively, in three batch coagulation sedimentation tanks out of four or more batch coagulation sedimentation tanks,
The water to be treated is continuously received in the three batch-type coagulation-sedimentation tanks in order, and the treated product by the coagulation-sedimentation treatment in the three batch-type coagulation-sedimentation tanks is continuously discharged in order.
Then, among the four or more batch type coagulation and settling tanks, in the batch type coagulation and settling tanks other than the three batch type coagulation and settling tanks, unsteady wastewater having a high concentration such as in-process blow drainage before the long-term shutdown of the factory can be used. Accepts abnormal wastewater in case of trouble independently and performs coagulation sedimentation treatment. After that, the processed product is discharged to the biological treatment tank 7 or the dehydration facility 4 in the subsequent stage while controlling the flow rate and the discharge time while considering the concentration of the treated product and the like.
By such wastewater treatment, it is possible to appropriately treat unsteady wastewater and abnormal wastewater having a high concentration while maintaining continuous reception and continuous wastewater by the batch type coagulation settling tank.

In the wastewater treatment method using a wastewater treatment system equipped with a batch type coagulation settling tank,
Each of at least two batch-type coagulation-sedimentation tanks has a receiving step for receiving the water to be treated, a coagulation-sedimentation treatment step for performing the coagulation-sedimentation treatment of the received water to be treated, and a discharge step for discharging the treated product by the coagulation-sedimentation treatment step. death,
In at least two batch coagulation and settling tanks, the receiving steps are carried out in sequence in succession.

The wastewater treatment system may be equipped with a measuring instrument for measuring the water to be treated. The measuring instrument preferably has an electric conductivity meter that measures the electric conductivity of the water to be treated.
The wastewater treatment system is based on the electric conductivity of the water to be treated received in each of at least two batch type coagulation and settling tanks, and the coagulant is added according to the relational expression between the electric conductivity prepared in advance and the amount of the coagulant added. It is preferable to have a chemical amount calculation unit for determining the amount. Then, in the coagulation-precipitation treatment, the coagulant is added to the water to be treated by the chemical addition device at the determined coagulant addition amount.
The electric conductivity may be measured by an electric conductivity meter. The electric conductivity meter may be provided in at least two batch coagulation and settling tanks, or may be provided in the flow path of the water to be treated to at least two batch coagulation and settling tanks. Further, the measuring instrument may have a pH meter in addition to the electric conductivity meter. The chemical amount calculation unit may adjust the amount of the pH adjuster added by the chemical addition device based on the measured value of the pH meter.
The electrical conductivity is a physical characteristic value according to the concentration of ions dissolved in water, but as the amount of pollutants in the wastewater increases, both the dissolved substances and the turbid substances increase in correlation with each other. It is a guide for the amount. Therefore, the amount of the inorganic flocculant, the polymer flocculant, and the pH adjuster added can be determined from the electrical conductivity of the water to be treated. As a result, even wastewater with large fluctuations in the amount of discharged water and the pollution concentration can be treated stably and appropriately. In addition, since an appropriate amount of chemicals can be determined, it is possible to suppress the addition of excessive chemicals, maintain good quality of treated water, and reduce the burden on the environment.

The chemical amount calculation unit calculates the amount of the coagulant added from the relational expression between the electric conductivity of the water to be treated and the amount of the coagulant added, which is prepared in advance, based on the electric conductivity (and pH if necessary) of the water to be treated. Calculate. The means for obtaining the above relational expression is not particularly limited.
For example, in advance, the electrical conductivity of the water to be treated, the amount of a flocculant suitable for treating the water to be treated (inorganic flocculant and polymer flocculant (preferably, further pH adjuster)), and It is possible to acquire the integrated data of and adopt the relational expression obtained from these.
When determining the relational expression, of the water to be treated for wastewater treatment, wastewater having normal electrical conductivity may be used. When the variation in the electrical conductivity of the water to be treated is large, it is preferable to acquire a plurality of data evenly according to the variation. Data using unsteady drainage with a high concentration such as blow drainage or abnormal drainage at the time of trouble may be acquired, and the relational expression in that case may be obtained.

As a measuring instrument, the wastewater treatment system is a flow meter (not shown) that measures the inflow of water to be treated into at least two batch coagulation settling tanks (for example, batch coagulation settling tank 1 and batch coagulation settling tank 2). ) And an electric conductivity meter (not shown) for measuring the electric conductivity of the water to be treated. The electric conductivity meter is not particularly limited, and a known one may be used.
The positions of the flow meter and the electric conductivity meter are not particularly limited, but a position where the inflow amount of the water to be treated into each coagulation sedimentation tank and the electric conductivity of the water to be treated can be continuously measured is preferable. For example, it may be near the entrance of the batch type coagulation settling tank.
Further, a flow meter and an electric conductivity meter may be provided in the supply line of the water to be treated to the batch type coagulation settling tank. The flowmeter and electrical conductivity meter may be installed anywhere on the supply line. It may be a portion where the supply lines are merged, that is, a portion where a single or a plurality of treated waters are mixed to form a uniform flow.

As shown in FIG. 3, the water to be treated supply line has a water receiving unit 21 to receive the water to be treated in the tank, and the water receiving unit 21 to be treated is a flow meter and an electric conductivity meter (more necessary). It may be equipped with a measuring instrument such as a pH meter). In the water receiving portion to be treated, a single or a plurality of waters to be treated are mixed to form a uniform flow. The water receiving portion to be treated is, for example, a member having a cylindrical shape or an inverted truncated cone shape.

With the flow meter, it is possible to grasp the amount of water to be treated in at least two batch type coagulation and settling tanks (for example, batch type coagulation and settling tank 1 and batch type coagulation and settling tank 2). In addition, the electric conductivity of the water to be treated can be grasped by the electric conductivity meter.
That is, since the amount of received water and the electric conductivity can be continuously measured by the flow meter and the electric conductivity meter, the average electric conductivity of the water to be treated contained in each of at least two batch type coagulation sedimentation tanks can be easily grasped. can do. Therefore, it becomes easy to determine the appropriate amount of the flocculant to be added, the addition of an excessive amount of chemicals can be suppressed, the quality of the treated water can be maintained well, and the burden on the environment can be reduced.

Preferably, the chemical amount calculation unit calculates the electric conductivity of the water to be treated from the indicated values of the flow meter and the electric conductivity meter, and the relational expression between the electric conductivity of the water to be treated prepared in advance and the amount of the flocculant added. The amount of coagulant added is determined by the above method, and the determined amount of coagulant added is output to the chemical addition device. When the amount of the coagulant added is input to the chemical addition device, in the coagulation / precipitation treatment, the coagulant (inorganic coagulant, polymer coagulant) and, if necessary, the pH adjuster are used in the coagulant addition device. Is added to the water to be treated.
As a result, after the water to be treated is supplied to each coagulation sedimentation tank, the coagulation sedimentation treatment can be automatically controlled.

For example, it can be controlled automatically by the following procedure.
First, the inorganic coagulant and the pH adjuster are added to the water to be treated by the chemical addition device in the determined coagulant addition amount. After the addition, while stirring at a predetermined rotation speed with a stirring device as necessary,
Allow a predetermined time to elapse. The rotation speed of the stirring device after the addition of the inorganic flocculant and the pH adjuster is preferably about 50 rpm to 500 rpm, and more preferably about 60 rpm to 200 rpm. The stirring time after the addition of the inorganic flocculant and the pH adjuster is preferably 0.5 to 10 minutes, more preferably 1 to 5 minutes.
After a lapse of a predetermined time, the polymer flocculant is added to the water to be treated to which the inorganic flocculant has been added in the determined amount of the flocculant added. After the addition, a predetermined time elapses while rapidly stirring at a predetermined rotation speed with a stirring device as needed to form flocs. Then, while stirring slowly at a predetermined rotation speed, a predetermined time elapses to enlarge the flocs. After that, the flocs are settled and separated by allowing them to stand for a predetermined time.
In the case of rapid stirring, the rotation speed after the addition of the polymer flocculant is preferably about 50 rpm to 500 rpm, and more preferably about 100 rpm to 200 rpm. In the case of slow-speed stirring, it is preferably about 10 rpm to 100 rpm, and more preferably about 30 rpm to 60 rpm. The stirring time of the polymer flocculant is preferably 0.5 minutes to 1.0 minutes in the case of rapid stirring, preferably 1.0 minutes to 10.0 minutes in the case of slow stirring, and more preferably 2 It is 0.0 minutes to 5.0 minutes, more preferably 2.5 minutes to 3.5 minutes.

Further, a flow meter (not shown) in which the wastewater treatment system 100 measures the inflow of water to be treated into at least two batch type coagulation and settling tanks (for example, batch type coagulation and settling tank 1 and batch type coagulation and settling tank 2). , And a flow path control device 6 for switching between receiving the water to be treated into the batch type coagulation and settling tank 1 and receiving the water to be treated into the batch type coagulation and settling tank 2. Then, using the indicated value of the flow meter as an input, the flow path control device 6 switches the acceptance of the water to be treated. Switching can be performed by the flow path switching valve 5 as described above.

Switching of acceptance of the water to be treated may be performed based on the indicated value of the flow meter and the volume of the batch type coagulation settling tank. Furthermore, since each corrugated board factory has its own production pattern characteristics, the timing of switching can be optimally and automatically controlled by converting the wastewater discharge cycle into data by machine learning. If the amount of water to be treated is small and there is room for acceptance even if the coagulation sedimentation treatment in the other coagulation sedimentation tank and the discharge of the treated product of the coagulation sedimentation treatment are completed, switching is performed depending on the acceptance time. May be determined.
This makes it possible to automatically control the acceptance of the water to be treated into the wastewater treatment system. Further, by using the flow meter and the flow path control device together with the above-mentioned chemical amount calculation unit and chemical addition device, it is possible to automatically control the acceptance of the water to be treated and the coagulation sedimentation treatment. Such a wastewater treatment system eliminates the need for human monitoring and adjustment even when the water quality of the treated water fluctuates greatly.

Further, the wastewater treatment system 100 discharges the supernatant liquid (treated water) in at least two batch coagulation sedimentation tanks to the biological treatment tank 7, and the sediment (sludge slurry) in the batch coagulation sedimentation tanks 1 and 2. It may have a discharge control device (not shown) and a discharge valve 24 for controlling the discharge of the waste to the dehydration facility 4.
In the coagulation-sedimentation treatment in the batch-type coagulation-sedimentation tank, the processed material can be discharged by the discharge control device after being allowed to stand for a predetermined time by sedimentation separation. The discharge control device controls the opening and closing of the discharge valve 24. This enables automatic control from the acceptance of the water to be treated to the discharge of the treated material in the coagulation sedimentation treatment. Further, the flow rate can be adjusted by adjusting the opening degree of the discharge valve 24 to keep the amount of water discharged to the biological treatment tank 7 constant.

A plurality of water supply lines C1 for discharging the supernatant liquid (treated water) from the batch type coagulation settling tank to the biological treatment tank 7 may be provided in the height direction of the batch type coagulation settling tank. For example, the embodiment shown in FIG. 5 can be mentioned. FIG. 5 is a diagram showing the wastewater treatment system 100 from the batch type coagulation sedimentation tank 1 to the biological treatment tank 7. In FIG. 5, it has a plurality of water supply lines C1-1, C1-2 and C1-3 from the batch type coagulation sedimentation tank 1 to the biological treatment tank 7. It should be noted that such a plurality of water supply lines can also be applied between another batch type coagulation sedimentation tank and the biological treatment tank 7.
By dividing the water level into a plurality of stages (three stages in FIG. 5), the supernatant liquid can be continuously discharged to the biological treatment tank 7 in response to various fluctuations in the amount of water to be treated. The number of stages of the water supply line is not particularly limited, and may be, for example, 2 to 4 stages.
For example, when the position of the maximum water level of the batch type coagulation settling tank is 100 and the position of the minimum water level is 0, the uppermost water supply line C1-1 is set to the position of 50 to 80, and the intermediate water supply line C1-2 is set to the position. The lower water supply lines C1-3 can be provided at positions 40 to 70 and at positions 20 to 50.

The wastewater treatment system can be suitably applied to wastewater having large fluctuations in the amount of discharged water and the pollution concentration. The single or more water to be treated is preferably wastewater generated in a food factory or a corrugated board factory. More preferably, it is wastewater generated in a corrugated board factory. In a corrugated board factory, the discharge timing of glue wash water and ink wash water differs depending on the manufacturing timing, so that the amount of discharged water and the contamination concentration tend to fluctuate greatly.

From the viewpoint of appropriately controlling the coagulation sedimentation treatment, the water to be treated is preferably wastewater from a factory or the like with relatively little wastewater. Process water, since this depends on the size of the coagulation-sedimentation tank is not particularly limited, for example, the processing amount of water per day, preferably 0.5m ³ /day~500.0m ³ / day, more preferably is 3.0m ³ /day~80.0m ³ / day, more preferably from 5.0m ³ /day~60.0m ³ / day.

(Biological treatment)
The wastewater treatment system 100 may include a biological reaction tank 3 for biologically treating the treated water of the batch type coagulation and settling tank after at least two batch type coagulation and settling tanks. In FIG. 3, the supernatant liquid (treated water) obtained by the coagulation-sedimentation treatment in the batch-type coagulation-sedimentation tank is sent to the biological treatment tank 7. In the biological treatment tank, biological treatment (biological treatment) is performed.
Biological treatment is roughly classified into an activated sludge treatment device using suspended sludge and a biological membrane treatment device in which sludge is supported on a carrier, and either device can be applied to the wastewater treatment system 100.

The activated sludge treatment equipment includes a standard activated sludge treatment equipment equipped with an aeration tank and a settling tank for returning sludge, a batch type activated sludge treatment device that alternately aerates and settles in one tank, and is immersed in an aeration tank. A membrane separation activated sludge treatment apparatus (MBR apparatus) that separates sludge and treated water with a separation membrane is preferable.
A batch type activated sludge treatment device and a membrane separation activated sludge treatment device (MBR device) are more preferable, and a membrane separation activated sludge treatment device (MBR device) is more preferable.

The standard activated sludge treatment equipment has a large number of equipment, and operations such as sludge return occur. The batch type activated sludge treatment equipment is suitable when the discharge regulation value is about the uniform standard of the Water Pollution Control Law, but when the operating time of the production equipment of the factory is long (when the downtime of one day is short), Some consideration is required for setting the batch operation.
The MBR device is a simple device with few elements to be adjusted, and the treated water quality is extremely good, and it is subject to any regulations such as SS (suspended solids amount) and BOD (biochemical oxygen demand). It is possible to respond. Moreover, since the SS concentration of the treated water is zero, even if a higher-order treatment device such as an activated carbon adsorption device is required for COD (Chemical Oxygen Demand) measures, additional installation is possible easily. It is desirable that the MBR device is divided into an aeration tank and a membrane separation tank, and has a structure that can absorb water level fluctuations in the aeration tank.

The biological film treatment device is roughly classified into a biological film filtration device and a contact oxidation device, and the contact oxidation device is further divided into a fixed bed device and a fluidized bed device. In the wastewater treatment system 100, a fixed floor device,
A fluidized bed device and a biological membrane filtration device are preferable, a fluidized bed device and a biological film filtration device are more preferable, and a biological film filtration device is further preferable.
In the fixed bed device and the fluidized bed device, the excess sludge mixed with the treated water affects the SS concentration, the BOD concentration, and the COD concentration. Therefore, when the water quality is equal to or lower than the uniform standard of the Water Pollution Control Law, it is preferable to return a part of the treated water to the coagulation sedimentation step to improve the treated water quality.
In the biofilm filtration device, since the fixed bed carrier layer installed in the aeration tank has a filtration function, the SS concentration, BOD concentration and COD concentration of the treated water can be satisfactorily reduced. Since the biofilm filtration device requires periodic backwashing treatment, it is preferable to return the backwashing treated water to the coagulation sedimentation treatment step.

(Sludge treatment)
The wastewater treatment system 100 may be provided with a dehydration facility 4 for solid-liquid separation of the sediment (sludge slurry) of the batch type coagulation and settling tank after at least two batch type coagulation and settling tanks. When the coagulation sedimentation treatment in the batch type coagulation sedimentation tank is completed, the sediment (sludge slurry) is drawn from the bottom of the coagulation sedimentation tank and sent to the dehydration facility 4, and the sludge treatment used for the sludge treatment is coagulation sedimentation. This is a step of dehydrating the sludge slurry drawn from the bottom of the tank to obtain dehydrated sludge having a water content of 60% to 80%. The dewatering equipment consists of a sludge storage tank and a dewatering device.

The sludge storage tank may be a concentration tank having a sedimentation separation function, and the concentration of the slurry to be sent to the dehydrator in the subsequent stage may be increased. Further, in the sludge storage tank, inorganic particles such as diatomaceous earth may be mixed with the sludge slurry to improve the operability of the dehydrator in the subsequent stage. The size of the sludge storage tank is preferably that it can store sludge slurry for half a day or more, more preferably it can store sludge slurry for one day or more, and further preferably it can store sludge slurry for 1.5 days or more. Further, the sludge storage tank is preferably provided with an aeration device and an agitator.

Examples of the dehydrating device include a screw press dehydrating device, a multiple disk dehydrating device, a belt press dehydrating device, a centrifugal dehydrating device, a filter press dehydrating device and the like. A combination of a multiple disk dehydrator, a screw press dehydrator, a multiple disk dehydrator and a screw press dehydrator, and a belt press dehydrator are preferable. A belt press dehydrator and a filter press dehydrator are more preferable, and a filter press dehydrator is even more preferable.
It is preferable that the dehydration filtrate is returned to the coagulation-precipitation step except for the filter press dehydrator. Since the dehydrated filtrate of the filter press dehydrator is clear, it may be discharged directly or sent to a biological treatment tank. The washing water such as the filter cloth of the filter press dehydrator may be sent to the coagulation sedimentation tank or the biological treatment tank.

(Second embodiment)
FIG. 4 relates to the wastewater treatment system of the second embodiment. The wastewater treatment system 100
As at least two batch-type coagulation and settling tanks, a batch-type coagulation and settling tank 1 that accepts a single or a plurality of treated waters and a batch-type agglomeration and settling tank 2 that accepts a single or a plurality of treated waters are provided. In FIG. 4, there are two batch type coagulation and settling tanks, but as in the first embodiment, the number of batch type coagulation and settling tanks may be three or more, or four or more.
The wastewater treatment system may also include a biological treatment tank 7 and a dehydration facility 4 downstream following at least two batch coagulation and settling tanks, as shown in FIG. The arrow (solid line or broken line) connecting each tank in the figure indicates the flow of water (treated water, treated water) or sludge slurry by a water supply line or the like.
The batch type coagulation and settling tanks 1 and 2, the biological treatment tank 7, and the dehydration equipment 4 are the same as those in the first embodiment. Other reference numerals are the same as those in the first embodiment.

In the second embodiment, the wastewater treatment system 100 uses at least two batch coagulation settling tanks (for example, a batch coagulation settling tank 1 and a batch coagulation settling tank 2) for a part of the treated water in the biological treatment tank 7.
) Is provided with a return line R that can be returned to. The return line R allows a part of the treated water to be returned to the coagulation-sedimentation step to improve the quality of the treated water.
When the biofilm treatment tank 7 is a biofilm filtration device, the backwashed water produced by the biofilm filtration device can be returned to the coagulation / precipitation treatment step by the return line R.

1,2: batch coagulation settling tank, 4: dehydration equipment, 5: flow path switching valve, 6: flow path control device, 7: biological treatment tank,
11: 1st adjustment tank, 12: 2nd adjustment tank, 13: 1st chemical mixing tank, 14: 2nd chemical mixing tank, 15: settling tank, 16: chemical mixing settling tank, 17: biological treatment adjustment tank 21: Water receiving part to be treated, 22: Chemical addition device, 23: Stirrer, 24: Discharge valve

Claims (14)

A wastewater treatment system equipped with a batch type coagulation settling tank.
The wastewater treatment system comprises at least two batch coagulation sedimentation tanks that receive one or more water to be treated.
The at least two batch coagulation sedimentation tanks are connected in parallel to the supply of the single or multiple treated waters.
The wastewater treatment system receives the water to be treated, performs the coagulation sedimentation treatment of the received water to be treated, and discharges the treated product by the coagulation sedimentation treatment in each of the at least two batch type coagulation sedimentation tanks.
A wastewater treatment system comprising continuously and sequentially receiving the water to be treated into the at least two batch coagulation and settling tanks. The at least two batch coagulation settling tanks have two batch coagulation settling tanks.
When the wastewater treatment system is performing the coagulation-sedimentation treatment of the water to be treated and the discharge of the treated product by the coagulation-sedimentation treatment in one of the two batch-type coagulation-sedimentation tanks, the two batch-type coagulation / sedimentation tanks are performed. On the other side of the settling tank, the water to be treated is received,
The wastewater treatment system according to claim 1, wherein the water to be treated is continuously and alternately received into the two batch coagulation sedimentation tanks. The at least two batch coagulation settling tanks have three batch coagulation settling tanks.
The water to be treated is continuously and sequentially received into the three batch coagulation and settling tanks.
The wastewater treatment system according to claim 1, wherein the treated matter is continuously discharged in order by the coagulation-sedimentation treatment in the three batch-type coagulation-sedimentation tanks. The at least two batch coagulation and settling tanks are provided with a chemical addition device and a stirrer for adding a coagulant to each of the at least two batch coagulation and settling tanks.
The wastewater treatment system according to any one of claims 1 to 3, wherein the coagulant is added by the chemical addition device in the coagulation sedimentation treatment. The wastewater treatment system includes a measuring instrument for measuring the water to be treated.
The measuring instrument has an electric conductivity meter for measuring the electric conductivity of the water to be treated.
The relationship between the electric conductivity prepared in advance and the amount of the agglutinating agent added based on the electric conductivity of the water to be treated received by the wastewater treatment system in each of the at least two batch type agglutination and settling tanks. It has a chemical amount calculation unit that determines the amount of coagulant added by the formula.
The wastewater treatment system according to claim 4, wherein in the coagulation-sedimentation treatment, the coagulant is added to the water to be treated by the chemical addition device at the amount of the coagulant added. The wastewater treatment system according to claim 5, wherein the measuring instrument comprises a flow meter for measuring the inflow of the water to be treated into the at least two batch coagulation sedimentation tanks. The chemical amount calculation unit
The electric conductivity of the water to be treated is calculated from the indicated values of the flow meter and the electric conductivity meter, and the amount of the flocculant added is determined by the relational expression.
The wastewater treatment system according to claim 6, wherein the determined amount of the coagulant added is output to the chemical addition device. The wastewater treatment system switches between a flow meter that measures the inflow of the water to be treated into the at least two batch coagulation and settling tanks and the acceptance of the water to be treated into the at least two batch coagulation and settling tanks. Equipped with a flow path control device,
The wastewater treatment system according to any one of claims 1 to 7, wherein the flow rate control device switches the acceptance of the water to be treated by using the indicated value of the flow meter as an input. The wastewater treatment system according to any one of claims 1 to 8, wherein the single or a plurality of treated waters are wastewater generated in a corrugated cardboard factory. Any of claims 1 to 9, wherein the wastewater treatment system includes a biological treatment tank for biologically treating the treated water of the at least two batch coagulation sedimentation tanks after the at least two batch coagulation sedimentation tanks. The wastewater treatment system described in item 1. The wastewater treatment system according to claim 10, wherein the biological treatment tank is a membrane separation activated sludge treatment device. The wastewater treatment system according to any one of claims 1 to 11, further comprising a dehydration facility for solid-liquid separation of the precipitates of the at least two batch coagulation sedimentation tanks after the at least two batch coagulation sedimentation tanks. The wastewater treatment system according to claim 12, wherein the dehydration facility has a filter press dehydrator. It is a wastewater treatment method using a wastewater treatment system equipped with a batch type coagulation settling tank.
The wastewater treatment system comprises at least two batch coagulation sedimentation tanks that receive one or more water to be treated.
The at least two batch coagulation sedimentation tanks are connected in parallel to the supply of the single or multiple treated waters.
The wastewater treatment method is
In each of the at least two batch type coagulation-sedimentation tanks, the receiving step of receiving the water to be treated, the coagulation-sedimentation treatment step of performing the coagulation-precipitation treatment of the received water to be treated, and the treated product by the coagulation-sedimentation treatment step are discharged. Has a discharge process,
A wastewater treatment method in which the receiving steps are continuously performed in sequence in the at least two batch type coagulation and settling tanks.

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