JP5993605B2 - Flocculant evaluation method and flocculant processing apparatus - Google Patents

Description

  The present invention relates to a flocculating ability evaluation method and a flocculating apparatus for a flocculant.

  When treating wastewater such as industrial wastewater and sewage, a flocculant is added to the wastewater to agglomerate and coarsen impurities such as ions, organic matter, suspended matter, etc., and then precipitate, float, etc. A method is generally used in which agglomerated water is filtered using a membrane filtration device and solid-liquid separation is performed after removing the agglomerates.

Here, when the agglomerated water is filtered using a membrane treatment device equipped with a microfiltration membrane (MF), an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), a nanofiltration membrane (NF), etc. The flocculant component that was not used (hereinafter also referred to as “unused flocculant component”) caused contamination of the surface layer of the membrane in the membrane filtration device, and there was a problem that sufficient membrane performance could not be obtained.
As a conventional method aiming at solving such a problem, for example, methods described in Patent Documents 1 and 2 can be cited.

  In Patent Document 1, in a coagulation treatment method in which an inorganic coagulant is added to raw water to coagulate, a separation liquid obtained by solid-liquid separation of the coagulation water is pressurized or suction filtered with a filter at a predetermined pressure. In addition, the filtration performance defined by the filtration time required to filter the predetermined amount of the separation liquid, or the amount of filtered water that can filter the separation liquid within the predetermined time, and the rate of change over time of the filtration performance are detected, When the detected filtration performance and the change rate with time of the filtration performance satisfy a preset reference value, the amount of inorganic flocculant added as a predetermined reference is maintained, and the change rate with time of the filtration performance and filtration performance is maintained. There is described an aggregating method characterized in that when at least one of them does not satisfy a preset reference value, the amount of inorganic flocculant added is adjusted.

  Patent Document 2 discloses a membrane filtration means for obtaining a filtrate by passing raw water through a filtration membrane, a filtrate amount measuring means for measuring the amount of filtrate from the membrane filtration means, and the filtrate. There is described a water quality monitoring device comprising an operation means for calculating a filtration coefficient from a measurement result of a quantity measuring means.

JP 2006-55804 A JP 2007-152192 A

  The method described in Patent Document 1 or 2 described above is based on a specific filtration membrane (hereinafter referred to as “evaluation filtration membrane”) obtained by adding a flocculant to waste water (treated water) and removing the aggregate. The amount of the unused flocculant component contained in the flocculated water is determined by measuring the degree of blockage and the like.

  However, in the conventional method as described in Patent Document 1 or 2, when the agglomerated treated water is filtered using the evaluation filtration membrane, the organic fouling substance contained in the agglomerated treated water blocks the evaluation filtration membrane. As a result, it was impossible to accurately measure the degree of membrane occlusion due to the unused flocculant component alone.

The present invention aims to solve the above-described problems.
That is, the present invention aims to provide a flocculating ability evaluation method capable of accurately measuring the degree of membrane clogging with only unused flocculant components when flocculated treated water is filtered using a filtration membrane for evaluation. And In addition, by grasping the optimum addition amount of the flocculant in the flocculation process by the aggregation ability evaluation method, and controlling the addition amount optimally based on that, the excess and deficiency of the flocculant addition amount can be prevented and efficient. An object of the present invention is to provide an aggregating apparatus capable of performing an aggregating process.

The present inventor diligently studied to solve the above problems, and when using a specific flocculant, the evaluation filter membrane made of a specific material is used to block the evaluation filter membrane with a fouling substance. It was found that the amount of the unused flocculant component can be accurately grasped, and the present invention has been completed.
The present invention includes the following (1) to (4).
(1) Aggregation ability for evaluating the aggregating ability of the aggregating agent in the case where the aggregating treatment water obtained by adding the aggregating agent to the water to be treated and removing at least a part of the aggregate is supplied to the membrane separator. An evaluation method,
The flocculant is an Al-based and / or Fe-based flocculant,
The aggregation-treated water is made of a material having hydrophilicity, and at least the surface layer is filtered using a filtration membrane for evaluation made of cellulose acetate, and the degree of blockage of the filtration membrane for evaluation is evaluated. A method for evaluating the aggregating ability of an agent.
(2) The method for evaluating aggregating ability according to (1) above, wherein the evaluation filtration membrane is made of cellulose acetate.
(3) A coagulation treatment apparatus comprising a coagulant addition means for adding a coagulant to the water to be treated,
The flocculant is an Al-based and / or Fe-based flocculant,
Further, the aggregation-treated water is made of a hydrophilic material, and at least the surface layer is filtered using a filter membrane for evaluation made of cellulose acetate, and the degree of blockage of the filter membrane for evaluation is evaluated. An aggregating apparatus comprising feedback means for adjusting an aggregating condition based on a result.
(4) The aggregation treatment apparatus according to (3), wherein the evaluation filtration membrane is made of cellulose acetate.

  According to the present invention, it is possible to provide a flocculating ability evaluation method capable of accurately measuring the degree of membrane clogging with only unused flocculant components when flocculated treated water is filtered using a filtration membrane for evaluation. . In addition, by grasping the optimum addition amount of the flocculant in the flocculation process by the aggregation ability evaluation method, and controlling the addition amount optimally based on that, the excess and deficiency of the flocculant addition amount can be prevented and efficient. It is possible to provide an aggregating apparatus that can perform an aggregating process.

It is the schematic which shows the suitable aspect of the apparatus of this invention.

The present invention will be described.
The present invention relates to an agglomeration for evaluating the aggregating ability of the aggregating agent in the case where an aggregating agent is added to the water to be treated and at least a part of the agglomerated material is removed to supply the agglomerated water to the membrane separator. Evaluation method, wherein the flocculant is an Al-based and / or Fe-based flocculant, the flocculated water is made of a material having hydrophilicity, and at least the surface layer is made of cellulose acetate. It is a coagulation ability evaluation method for evaluating the coagulation ability of the coagulant by filtering using a membrane and evaluating the degree of blockage of the evaluation filtration membrane.
Hereinafter, such a coagulation ability evaluation method is also referred to as “the evaluation method of the present invention”.

Further, the present invention is an aggregating apparatus provided with an aggregating agent adding means for adding an aggregating agent to water to be treated, wherein the aggregating agent is an Al-based and / or Fe-based aggregating agent, and further, the aggregating treatment Water is made of a material having hydrophilicity, and at least the surface layer is filtered using a filter membrane for evaluation made of cellulose acetate, the degree of blockage of the filter membrane for evaluation is evaluated, and aggregation is performed based on the evaluation result. It is a coagulation processing apparatus provided with the feedback means which adjusts conditions.
Hereinafter, such an aggregating apparatus is also referred to as “the apparatus of the present invention”.

  The feedback means in the apparatus of the present invention is means for using the evaluation method of the present invention.

  First, the evaluation method of the present invention will be described.

<Filtration membrane for evaluation>
The filtration membrane for evaluation in the evaluation method of the present invention will be described.
In the evaluation method of the present invention, the evaluation filtration membrane is made of a material having hydrophilicity, and at least the surface layer is made of cellulose acetate. When the agglomerated treated water after adding a specific flocculant to be described later is filtered using the evaluation filtration membrane of such an embodiment, the fouling substances contained in the agglomerated treated water do not block the evaluation filtration membrane, Since only the used flocculant component clogs the evaluation filtration membrane, the degree of membrane clogging with only the unused flocculant component can be accurately measured, and as a result, the amount of unused flocculant component contained in the flocculated water The present inventor has found that it is possible to know accurately.

  An aspect in which a film is formed by applying liquid cellulose acetate to the surface of a filtration membrane made of a material having hydrophilicity, as a filtration membrane for evaluation made of a material having hydrophilicity and at least the surface layer being made of cellulose acetate Can be mentioned.

  Moreover, it is preferable that the filtration membrane for evaluation consists of a cellulose acetate also about parts other than a surface layer. When the present invention has been intensively studied, the surface layer portion in the evaluation filtration membrane is made of cellulose acetate, and the whole portion is made of cellulose acetate compared to the case where the portion other than the surface layer is made of a material having hydrophilicity other than cellulose acetate. It was found that the fouling substance contained in the flocculated water does not cause more clogging in the evaluation filtration membrane comprising

Further, the evaluation filtration membrane according to the present invention indicates that, even if the surface layer is cellulose acetate, the fouling substance contained in the agglomerated treated water blocks the filtration membrane if the other part is made of a hydrophobic material. Found.
The reason for this is not clear, but if there is a material with hydrophobicity on the surface even if very little, the fouling substance gradually accumulates on the filtration membrane for evaluation and clogs it starting from that material. The inventor presumes that this is the case.

  Here, a conventionally known material can be used as the “material having hydrophilicity”. A material having hydrophilicity can also be considered as a material that can be repeatedly dried and wetted when used. Here, the dried state means the same state as that after 24 hours of drying at 35 ° C., and the wet state means a state that is wetter than the dried state.

Cellulose acetate corresponds to a material having hydrophilicity, and other materials having hydrophilicity include polyacrylonitrile, polyvinyl alcohol, ethylene vinyl alcohol, and polyvinylpyrrolidone. As the material having hydrophilicity, it is preferable to use at least one selected from the group consisting of cellulose acetate, polyacrylonitrile, polyvinyl alcohol, ethylene vinyl alcohol, and polyvinyl pyrrolidone.
Polytetrafluoroethylene and polyvinylidene fluoride do not correspond to materials having hydrophilicity.

  For example, a filter membrane made of a mixture of cellulose nitrate and cellulose acetate or a material in which cellulose nitrate and cellulose acetate are combined at the molecular level does not correspond to the evaluation filter membrane used in the evaluation method of the present invention.

The filter membrane for evaluation is not particularly limited with respect to matters other than the materials described above, and may be the same as a conventionally known one, for example.
For example, the thickness of the evaluation filtration membrane is not particularly limited, and may be, for example, 50 to 500 μm.

  Further, the pore diameter of the evaluation filtration membrane is not particularly limited, and may be, for example, 0.01 to 0.45 μm, preferably 0.1 to 0.45 μm, and preferably 0.22 to 0.45 μm. Is more preferable, and about 0.22 μm is more preferable. This is because the fouling substance contained in the agglomerated treated water does not cause the evaluation filtration membrane to be more clogged with such a preferable pore size. Further, when the agglomerated treated water is filtered using the evaluation filter membrane, the speed until the unused aggregating agent component contained in the agglomerated treated water is captured and brought into a predetermined blocked state is relatively high.

The pore structure of the evaluation filtration membrane may be a sponge shape, a slit shape, or a right cylindrical shape, but more preferably a sponge shape. This is because the fouling substance contained in the agglomerated treated water does not cause more clogging of the evaluation filtration membrane. Further, when the agglomerated treated water is filtered using the evaluation filter membrane, the speed until the unused aggregating agent component contained in the agglomerated treated water is captured and brought into a predetermined blocked state is relatively high.
Here, the sponge-like pore structure has almost the same structure from the front to the back of the membrane, and the pore shape means a structure in which a number of layers of network-like structures overlap. To do.
In addition, the slit-like pore structure means a structure in which a plurality of layers of slit-like and curtain-like structures are overlapped.
In addition, a straight cylindrical pore structure means that a cylindrical hole passes in parallel in the cross-sectional direction of the membrane.
For example, Shinichi Nakao, “Fundamentals of separation membranes” by the Industrial Research Committee, P80, photographs showing the membrane structure of “cellulose acetate + nitrocellulose mixed membrane” and “polyvinylidene fluoride” are published. Each of these photographs shows a sponge-like pore structure. The publication also includes a photograph showing the membrane structure of “polytetrafluoroethylene”, which shows a slit-like pore structure. The publication also includes a photograph showing the membrane structure of “polycarbonate”, which shows a right cylindrical pore structure.

  In the operation of adding the specific flocculant described later to the water to be treated containing impurities such as ions, organic matter, suspended matter, etc., and aggregating the impurities, when evaluating the flocculant ability of the flocculant, When the evaluation filter membrane is used, the fouling substance contained in the water to be treated does not block the filtration membrane for evaluation, and only the unused flocculant component blocks the filtration membrane for evaluation. The degree of membrane occlusion by only the agent component can be accurately measured, and as a result, the aggregating ability of the aggregating agent can be accurately grasped.

<Flocculant>
The flocculant in the evaluation method of the present invention will be described.
In the evaluation method of the present invention, a flocculant is added to the water to be treated. Then, impurities such as ions, organic substances, suspended substances and the like contained in the water to be treated are aggregated to form aggregates.
The flocculant in the evaluation method of the present invention is an Al-based and / or Fe-based flocculant.

The Al-based flocculant means a flocculant mainly composed of an aluminum compound.
Here, the aluminum compound means a compound containing Al atoms. Examples of the aluminum compound include polyaluminum chloride and sulfuric acid clay (aluminum sulfate).

The main component is a content of 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass. It means that the content is at least mass%, more preferably at least 98 mass%, more preferably at least 99 mass%, and even more preferably at 100 mass% (substantially does not contain other components). Here, “substantially free of other components” means that impurities that are inevitably included from the raw materials and the production process may be included, but the other components are not included.
In the following description of the present invention, “main component” is used in this sense unless otherwise specified.

The Fe-based flocculant means a flocculant mainly composed of an iron-based compound.
Here, the iron-based compound means a compound containing Fe atoms. Examples of iron-based compounds include ferric chloride and polyferric sulfate.

  The flocculant may be in a powdery form, or in a form in which a powdery aluminum-based compound and / or iron-based compound is dispersed in a liquid.

In the evaluation method of the present invention, such an Al-based flocculant, an Fe-based flocculant, or a flocculant containing both as main components is added to the water to be treated. Here, when used as a flocculant containing both an Al-based flocculant and an Fe-based flocculant, the mixing ratio thereof is not particularly limited.
In the evaluation method of the present invention, it is preferable to use an Al-based flocculant as the flocculant.

<Treatment water>
The treated water in the evaluation method of the present invention will be described.
In the evaluation method of the present invention, the water to be treated is not particularly limited as long as it contains water such as ions, organic substances, suspended substances and the like that can aggregate when the flocculant is added and a fouling substance. Here, the ions include phosphorous phosphorus, ammonia nitrogen, iron ions, manganese ions, aluminum ions, silica ions, and the like.
In addition, the fouling substance is an organic substance that can cause clogging when membrane separation by a membrane separation apparatus is continuously performed, and the present inventor considers that humic substances and polysaccharide-like substances are applicable. Yes.

  The treated water may further contain pathogenic microorganisms and the like.

Specific examples of the water to be treated include raw tap water (river water, groundwater, etc.), seawater, and the like.
In addition, the water to be treated may be one obtained by subjecting raw water water or the like specifically mentioned here to some kind of treatment (for example, debris treatment, precipitation treatment, biological treatment, etc.).

<Aggregated treated water>
The agglomerated water in the evaluation method of the present invention will be described.
In the evaluation method of the present invention, the flocculated water is obtained after adding the flocculating agent to the water to be treated, and separating and removing at least a part of the generated aggregate. For example, the supernatant obtained by adding the flocculant to the water to be treated, separating and removing the agglomerates by carrying out the treatment usually used for processing using a membrane separator such as precipitation and flotation is agglomerated. Corresponds to treated water.

<Evaluation method>
In the evaluation method of the present invention, the aggregated treated water after the addition of the Al-based and / or Fe-based flocculant to the treated water is filtered using a specific evaluation filtration membrane, and the evaluation filtration is performed. By evaluating the degree of blockage of the membrane, the aggregating ability of the aggregating agent can be evaluated.

The evaluation method is not particularly limited as long as the aggregation treated water is filtered using the evaluation filtration membrane and the degree of blockage of the evaluation filtration membrane is evaluated.
For example, set the filtration membrane for evaluation in a flat membrane filter holder, perform constant pressure filtration using a suction pump to keep the suction pressure constant, and filter the evaluation filter according to the decrease in suction speed when a predetermined amount is filtered. The degree of membrane occlusion can be evaluated.
Also, for example, the evaluation filtration membrane is set in a conventionally known stirring-type pressure cell, subjected to constant speed filtration, and the degree of blockage of the evaluation filtration membrane is determined by the increase in suction pressure when a predetermined amount is filtered. Can be evaluated.

  In the evaluation method of the present invention, the above-described evaluation is performed, and based on the evaluation result, the optimum amount of the flocculant is added to the flocculated water by adjusting the amount of the flocculant added to the flocculated water. Then, when the agglomerated water is supplied to the membrane separator, it is possible to prevent the membrane of the membrane separator from being contaminated by the unused flocculant.

  In the evaluation method of the present invention, a microfiltration membrane (MF), an ultrafiltration membrane (UF), a reverse osmosis membrane (RO), a nanofiltration membrane (NF) or the like can be used as a membrane treatment apparatus.

Next, the apparatus of the present invention will be described.
The apparatus of the present invention includes feedback means using the above-described evaluation method of the present invention.

The apparatus of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing a preferred embodiment of the apparatus of the present invention.
In FIG. 1, the apparatus 1 of the present invention is a flocculation processing apparatus including a flocculating agent storage tank 7 as a flocculating agent adding means for adding a flocculating agent 6 to the water 4 to be treated, and further includes a flocculating process including a feedback means 9. Device. Here, the flocculant storage tank 7 is provided with a cutting device, and may be a mode in which, for example, a conventionally known cutting device is provided in a lower portion of a conventionally known storage tank.
Further, the apparatus 1 of the present invention shown in FIG. 1 further stores the raw water 2 and discharges the supernatant liquid as the treated water 4, receives the treated water 4 and mixes it with the flocculant 6, The agitation agitation tank 5 that discharges the supernatant as the agglomerated water 8, the agglomerated water 8 that is stored to precipitate the sediment, the precipitation tank 11 that discharges the supernatant, and the supernatant that is discharged from the precipitation tank 11 And a filtering device 13 for filtering.
The agglomerated water discharged from the filtration device 13 is supplied to the membrane separation device. The membrane separation apparatus may be the same as that used in the evaluation method of the present invention.

  The feedback means 9 is a means for collecting a part of the flocculated water 8 and evaluating it by the evaluation method of the present invention, and adjusting the flocculation conditions based on the result. For example, when the degree of blockage of the evaluation filtration membrane is too small, adjustment is made to increase the amount of the flocculant 6 added to the flocculation agitation tank 5. On the contrary, for example, when the degree of blockage of the evaluation filter membrane is too large, the amount of the flocculant 6 added to the flocculation stirring tank 5 is adjusted to be small. Adjustment of the addition amount of the flocculant 6 to the flocculent stirring tank 5 is performed by sending an electrical signal from the control means to the cutting device provided in the flocculant storage tank 7, for example. You can also. Although such computer control may be performed, humans may intervene and the amount of the coagulant 6 added to the coagulation stirring tank 5 may be manually adjusted based on the evaluation result.

  The flocculant used in the flocculant addition means of the apparatus of the present invention is an Al-based and / or Fe-based flocculant, similar to the flocculant used in the evaluation method of the present invention.

  In addition, the raw | natural water tank 3, the aggregation stirring tank 5, the precipitation tank 11, and the filtration apparatus 13 with which the apparatus 1 of this invention is provided may be a conventionally well-known thing. The raw water tank 3 and the sedimentation tank 11 may be, for example, a conventionally known tank-shaped tank, and the agglomeration stirring tank 5 may be of a conventionally known aspect further provided with stirring means. Moreover, the filtration apparatus 13 may be a sand filtration apparatus, a multilayer filtration apparatus, and a fiber filtration apparatus, for example.

<Example 1>
A filtration membrane for evaluation made of cellulose acetate (a flat membrane with a diameter of 25 mm, a pore size: 0.22 μm, a pore structure: sponge-like) was prepared. Hereinafter, this evaluation membrane is also referred to as “evaluation membrane A”.

Next, Edogawara water was prepared as treated water. The composition of Edogawara water was as follows.
pH 7.5
Turbidity 3.6 degrees Iron 0.29 mg / L
Manganese 0.027mg / L
Aluminum 0.15mg / L
UV _A260 (5cm) 0.112

Next, after adding polyaluminum chloride as a flocculant to said to-be-processed water at 30 mg / L, it stirred using the jar tester. Stirring with a jar tester was performed under the condition of stirring at 130 rpm for 3 minutes, then stirring at 30 rpm for 10 minutes, and then standing for 5 minutes.
And the supernatant liquid was obtained as aggregation process water.

Next, the filtration membrane A for evaluation was set in a flat membrane glass filter holder (effective membrane area: 2.1 cm ² ), and this was used to filter the agglomerated treated water (400 mL) after stirring with a jar tester. . At the time of the filtration, a suction pump was used to perform a constant volume filtration with a constant suction pressure (92 kPa).

  And the deposit (namely, clogging substance) deposited physically and irreversibly on the surface layer of the filter membrane 1 for evaluation after filtering 400 mL of flocculated water was investigated. The survey was conducted using FTIR and EDX. As a result, the deposits were all polyaluminum chloride and contained no fouling material.

<Comparative Example 1>
A filtration membrane for evaluation made of hydrophobic polyvinylidene fluoride (a flat membrane with a diameter of 25 mm, a pore size: 0.22 μm, a pore structure: sponge-like) was prepared. Hereinafter, this evaluation membrane is also referred to as “evaluation membrane B”.
Next, the evaluation filtration membrane B was set in a flat membrane glass filter holder in the same manner as in Example 1, and 400 mL of the agglomerated treated water was filtered using this as in Example 1.
And like Example 1, the deposit deposited on the surface layer of the filter membrane B for evaluation after filtering 400 mL coagulation treated water was investigated.
As a result, the sediment contained a large amount of fouling material.

<Comparative example 2>
An evaluation filtration membrane (a flat membrane with a diameter of 25 mm, a pore size: 0.22 μm, a pore structure: sponge-like) was prepared by applying a hydrophilic polymer to the surface of polyvinylidene fluoride, which is a hydrophobic material. Hereinafter, this evaluation membrane is also referred to as “evaluation membrane C”.
Such an evaluation filtration membrane C was set in a flat membrane glass filter holder in the same manner as in Example 1, and 400 mL of the agglomerated treated water was filtered in the same manner as in Example 1.
And like Example 1, the deposit deposited on the surface layer of the filter membrane C for evaluation after filtering 400 mL aggregation process water was investigated.
As a result, the sediment contained a large amount of fouling material.

<Comparative Example 3>
As a filtration membrane for evaluation, cellulose mixed ester MF (pore diameter 0.45 μm) manufactured by Millipore was prepared. Hereinafter, this evaluation membrane is also referred to as “evaluation membrane D”.
Since the evaluation filtration membrane D is made of a material having a structure in which cellulose nitrate and cellulose acetate are bonded at the molecular level, the surface layer of the evaluation filtration membrane D is not made only of cellulose acetate.
Such an evaluation filtration membrane D was set in a flat membrane glass filter holder in the same manner as in Example 1, and 400 mL of the agglomerated treated water was filtered in the same manner as in Example 1.
And like Example 1, the deposit deposited on the surface layer of the filter membrane D for evaluation after filtering 400 mL coagulation treated water was investigated.
As a result, the sediment contained a large amount of fouling material.

<Comparative example 4>
A filtration membrane for evaluation made of polycarbonate (a flat membrane with a diameter of 25 mm, a pore size: 0.22 μm, a pore structure: a right cylindrical shape) was prepared. Hereinafter, this evaluation filtration membrane is also referred to as “evaluation filtration membrane E”.
Such an evaluation filtration membrane E was set in a flat membrane glass filter holder in the same manner as in Example 1, and 400 mL of the agglomerated treated water was filtered in the same manner as in Example 1.
And like Example 1, the deposit deposited on the surface layer of the filter membrane E for evaluation after filtering 400 mL coagulation treated water was investigated.
As a result, the sediment contained a large amount of fouling material.

<Comparative Example 5>
An evaluation filtration membrane (a flat membrane with a diameter of 25 mm, a pore size: 0.22 μm, a pore structure: a slit shape) in which a hydrophilic polymer is applied to the surface of polytetrafluoroethylene, which is a hydrophobic material, was prepared. Hereinafter, this evaluation filtration membrane is also referred to as “evaluation filtration membrane F”.
Such an evaluation filtration membrane F was set in a flat membrane glass filter holder in the same manner as in Example 1, and 400 mL of the agglomerated treated water was filtered in the same manner as in Example 1.
And like Example 1, the deposit deposited on the surface layer of the filter membrane F for evaluation after filtering 400 mL aggregation process water was investigated.
As a result, the sediment contained a large amount of fouling material.

DESCRIPTION OF SYMBOLS 1 Apparatus of this invention 2 Raw water 3 Raw water tank 4 Water to be treated 5 Coagulation stirring tank 6 Coagulant 7 Coagulant storage tank 8 Coagulated water 9 Feedback means 11 Precipitation tank 13 Filtration apparatus

Claims (4)

Add at least one of Al-based and Fe-based flocculants to the water to be treated,
The agglomerated water to which the aggregating agent is added is made of a material having hydrophilicity, has a thickness of 50 to 500 μm, a pore diameter of 0.01 to 0.45 μm, and a pore structure of sponge shape, slit shape, right cylindrical shape Filter using one of the filtration membranes for evaluation,
After the addition of the flocculant, the flocculation treatment water is filtered by the evaluation filtration membrane fouling substances contained in the aggregation treatment water without clogging a filter membrane for the evaluation, unused aggregate that has not been utilized in the cohesive Measure the degree of membrane occlusion of the evaluation filtration membrane blocked only by the agent component,
A method for evaluating aggregating ability, comprising evaluating the aggregating ability of the aggregating agent. The aggregation membrane evaluation method according to claim 1, wherein at least the surface layer of the evaluation filtration membrane is made of cellulose acetate. A flocculant addition means for adding a flocculant of at least one of Al-based and Fe-based to the water to be treated to obtain the agglomerated treated water;
The agglomerated water after the addition of the aggregating agent is made of a material having hydrophilicity, has a thickness of 50 to 500 μm, a pore diameter of 0.01 to 0.45 μm, and a pore structure of sponge shape, slit shape, right cylindrical shape. The membrane is filtered through one of the evaluation filtration membranes, and the membrane clogging degree that clogs the filtration membrane for evaluation with only unused flocculant components that have not been used for aggregation is determined by measurement, and the aggregation ability of the flocculant is evaluated. Feedback control means for adjusting the amount of the flocculant added by the flocculant addition means based on the evaluation result;
A filtration device for filtering the agglomerated water whose amount of the flocculant is adjusted by the feedback control means and supplying it to the membrane separator;
An agglomeration processing apparatus comprising: The feedback control means includes
4. The aggregation according to claim 3, wherein the amount of addition is increased when the degree of membrane occlusion is small, and the amount of addition is reduced when the degree of membrane occlusion is large, according to the evaluation result. Processing equipment.

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