JP2010131469A - Membrane separation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably and efficiently perform membrane separation treatment for a long period of time by improving water quality of membrane feed water before performing the membrane separation treatment of separated water obtained by adding an alkaline solution of a phenol-based polymer to raw water, then adding an inorganic coagulant to perform coagulation treatment, and subjecting coagulation-treated water to solid-liquid separation. <P>SOLUTION: The alkaline solution of the phenol-based polymer, which has phenolic hydroxyl groups, is alkali-soluble, and becomes insoluble in a neutral region and/or in the presence of high salts, is diluted to a predetermined concentration and then added to the raw water. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to the production of pure water by membrane separation treatment of industrial water, or the production of pure water and / or process water by membrane separation treatment of waste water treatment water, or seawater and / or brine water as a membrane. In the case of producing living water such as drinking water and various industrial water through separation treatment, the efficiency of the aggregation treatment performed prior to the membrane separation treatment is increased, and the MFF value of water supplied to the membrane separation treatment is improved. The present invention relates to a membrane separation processing method.

  Membrane separation treatment technology is used in many water treatment fields, such as the production of pure water from industrial water, the production of pure water and process water from wastewater treatment water, and the production of domestic and industrial water such as drinking water from seawater and brackish water. Used in.

  In the membrane separation treatment, the water to be treated (raw water) is usually subjected to agglomeration / solid-liquid separation treatment prior to the membrane separation treatment. In this aggregating treatment, polyaluminum chloride and ferric chloride, which are inorganic aggregating agents, are usually used, and an organic polymer aggregating agent is not used in combination. In other words, in the usual coagulation treatment of waste water and water without membrane separation treatment, polyacrylamide anionic polymer coagulant and cationic polymer coagulant are used together with inorganic coagulant for the purpose of coarsening the coagulation flocs. However, if these polymer flocculants remain in the agglomerated water even in a small amount, they cause membrane contamination and lower the permeation flux (flux), so they are mostly used for agglomeration prior to membrane separation treatment. There is no.

Therefore, when the raw water is subjected to membrane separation treatment with MF (microfiltration) membrane, UF (ultrafiltration) membrane, RO (reverse osmosis) membrane, etc., pretreatment processes such as aggregation and solid-liquid separation prior to membrane separation treatment and Although there are many combinations, the basic processes that have been generally adopted are as follows.
(1) Coagulation treatment process After adding an inorganic flocculant to the raw water and reacting it, solid-liquid separation is performed by a flotation device or a precipitation device.
(2) Filtration process Aggregated water with an inorganic flocculant is passed through a sand filter or a two-layer filtration device to remove fine particles having a particle size of about 5 μm to 2 μm. Subsequently, activated carbon adsorption treatment may be performed to remove soluble organic substances.

  In addition to the addition of a flocculant in the agglomeration process, the pretreatment includes sodium hypochlorite, an organic disinfectant / antibacterial agent, RO membrane for preventing the growth of organisms in the system as a chemical treatment. A decomposition agent for residual chlorine that causes deterioration, a scale formation inhibitor for the RO membrane, and the like are appropriately added.

  These pretreatments are appropriately selected and used depending on the pollution degree of raw water, the obstacles expected in the membrane separation treatment, and the finally obtained level of treated water.

  However, in the above conventional coagulation treatment process, water-soluble membrane contaminants remain, and although there are differences in the degree depending on the turbidity of the raw water, there is a considerable amount of membrane contamination, and the treatment is stopped at the RO membrane and UF membrane. Chemical cleaning of the membrane and further replacement of the membrane module are required, and unit replacement is required for the MF membrane.

This film pollutant is divided roughly into an organic substance and an inorganic substance.
Among these, membrane-contaminated inorganic substances are scaled beyond solubility due to concentration of inorganic ions and silica in raw water by membrane separation treatment, and aluminum and iron caused by inorganic flocculants as hydroxide colloids with extremely fine particles Residual and directly contaminate the membrane and result from scaling in combination with silica in the water.
On the other hand, membrane-contaminated organic matter is considered to be a polysaccharide that is metabolized by natural water microbial activity and biological treatment of wastewater. In addition to this, humic and fulvic substances derived from natural humus are also considered as membrane pollutants. It is said that.

In the agglomeration process, it is required to remove these organic film contaminants as much as possible, but in the agglomeration process with an inorganic flocculant, film contaminants that cannot be removed remain.
The specific substances are presumed to be neutral polysaccharides having no charge or polysaccharides having very little charge.

Incidentally, there is an “MFF value” as an index of membrane filterability (membrane contamination) of water to be subjected to membrane separation (membrane supply water). The measuring method of this MFF value is as follows.
(1) Aggregation treatment with a jar tester gives 1000 ml or more of aggregation treatment water.
(2) The flocculated water is allowed to stand for 30 minutes to precipitate the flocculated floc.
(3) The aggregation-treated water of (2) is No. Slowly filter from the supernatant with 5A (5 μm pore) filter paper, and finally filter the entire amount of the flocculated water including the flocculated floc.
(4) Place 1000 ml or more of the obtained filtrate into two graduated cylinders, 500 ml each.
(5) Filter 500 ml of the filtrate of the first graduated cylinder using a nitrocellulose membrane filter with a pore diameter of 0.45 μm and a diameter of 47 mm under reduced pressure of 66 kPa (500 mmHg), and measure the time T1 required for filtration at this time To do. Subsequently, 500 ml of the filtrate of another graduated cylinder is similarly filtered under reduced pressure, and the time T2 required for filtration at this time is measured.
(6) The MFF value is calculated by the following formula.
MFF = T2 / T1

The closer this value is to 1.00, the better the water quality of the membrane supply water, and it can be evaluated that the membrane supply water is less likely to contaminate the membrane. It is said to be suitable as water.
For example, the MFF of tap water (Nogi-cho, Tochigi Prefecture) is 1.03 to 1.06, which is 1.05 on average, and can be said to be ideal water quality from the degree of organic contamination as membrane supply water.

As a technique for improving the quality of the membrane feed water when the raw water is biologically treated and the biologically treated water is subjected to membrane separation treatment, the applicant firstly added a polymer having a phenolic hydroxyl group to the biologically treated water. , A method of adding a ferric chloride as an inorganic flocculant to agglomerate the membrane and subjecting the treated water to a membrane separation treatment, and a coagulation accelerator for biologically treated water comprising a vinylphenol polymer (Patent Document 1) ).
However, the MFF of the membrane feed water by this method is 1.3, which is not a technique for stably obtaining a satisfactory level (MFF ≦ 1.1).
Furthermore, since the polyvinylphenol polymer is expensive, even if the amount of the inorganic flocculant added can be reduced, the overall drug cost cannot be reduced sufficiently.

In addition, the present applicant has proposed polyvinylphenol used in Patent Document 1 as an insolubilizing agent for a nonionic surfactant (Patent Document 2).
Among them, a novolak type phenol resin having a structure similar to polyvinylphenol was evaluated. This is because the TOC (total organic carbon) of the treated water is higher than the raw water (treated water), so that it is not suitable as the treating agent. Appropriate.
However, the phenol resin is inexpensive and advantageous in terms of cost compared to the polyvinylphenol polymer.
JP 2007-7563 A Japanese Patent No. 2830201

  The present invention has been made in view of the above-described conventional situation, and after adding an alkaline solution of a phenolic polymer compound to raw water, an inorganic flocculant is added to perform agglomeration treatment, and the agglomerated water is separated into solid and liquid And providing a membrane separation treatment method that enables stable and efficient membrane separation treatment to be carried out for a long period of time by improving the quality of the membrane feed water in the membrane separation treatment of the separated water obtained. For the purpose.

  As a result of intensive studies to solve the above problems, the present inventors have diluted an alkali solution of a phenolic polymer compound having a phenolic hydroxyl group and insoluble in a neutral region and / or high salt to a predetermined concentration. It was found that the MFF value of the membrane feed water can be further improved by adding to the raw water.

That is, in the agglomeration treatment in which an alkaline solution of a phenolic polymer compound is added, film-fouling organic substances are agglomerated and removed by utilizing the property that the phenolic polymer compound is precipitated in a neutral region. However, for the same reason, the precipitated phenolic polymer compounds are associated and precipitated, and no longer react with the membrane contaminants in the water to be treated, resulting in an increase in the amount of the required phenolic polymer compound added. It was.
On the other hand, the phenolic polymer compound concentration when adding the phenolic polymer compound is sufficiently reduced, and the alkali solution of the phenolic polymer compound is sufficiently diluted to be added in the coagulation treatment system. This reduces the frequency of association between the phenolic polymer compounds, prevents it from precipitating and becoming ineffective as a flocculant, and can further improve the MFF value of the membrane feed water. The addition amount of the molecular compound itself can also be reduced, and the amount of drug used and the cost of the drug can be reduced.

Further, as described above, the phenol resin is inexpensive, but by adding it, the TOC of the agglomerated treated water becomes higher than that of the raw water, which is not suitable as an aggregating agent. According to the study by the present inventors, this cause is that a large amount of the resin component itself that does not precipitate in the neutral region remains in the added phenol resin, which is thought to increase the TOC of the treated water. .
Such a phenol resin is also sufficiently diluted according to the present invention and added to the raw water, whereby the addition amount itself is reduced, the residual amount of the phenol resin in the treated water is reduced, and the problem of TOC increase is solved.

In general, the aggregating agent is added to the raw water under conditions of high concentration within the physically possible range. For example, as for polyaluminum chloride, a stock solution of Al ₂ O ₃ 10 wt% is poured as it is with a pump.
The alkaline solution of the phenolic polymer compound used in the present invention exhibits sufficient fluidity at a phenolic polymer compound concentration of 20 wt / vol%, and is usually prepared as a concentration of about 10 to 35 wt / vol%, and this is directly used as raw water. Can be added.
Therefore, in the past, a phenolic polymer compound was added as an alkaline solution having such a high concentration. It has been found that when added, the MFF value of the agglomerated treated water is remarkably improved and the required addition amount can be reduced.

  The present invention has been achieved on the basis of such findings, and the gist thereof is as follows.

  In the membrane separation treatment method of the present invention (invention 1), after adding an alkaline solution of a phenolic polymer compound to seawater or water to be treated which is high salt-containing water having an electric conductivity of 1000 mS / m or more, inorganic agglomeration is performed. In the method of coagulating by adding an agent, solid-liquid separation of the agglomerated treated water, and membrane separation treatment of the obtained separated water, the phenolic polymer compound is alkali-soluble, neutral, having a phenolic hydroxyl group A high molecular compound that is insolubilized in the presence of a zone and / or a high salt, and the high molecular compound is added to the water to be treated as an alkaline solution having a high molecular compound concentration of 0.1 wt / vol% or less.

  In the membrane separation treatment method of the present invention (Claim 2), an alkaline solution of a phenolic polymer compound is added to water to be treated having an electrical conductivity of less than 1000 mS / m, and then an inorganic flocculant is added to perform the agglomeration treatment. In the method of solid-liquid separation of the agglomerated treated water and membrane separation treatment of the obtained separated water, the phenolic polymer compound is alkali-soluble having a phenolic hydroxyl group, in the neutral region and / or in the presence of high salts. The polymer compound is insolubilized by the addition of the polymer compound to the water to be treated as an alkaline solution having a polymer compound concentration of 1 wt / vol% or less.

  A membrane separation treatment method according to a third aspect is the method according to the first or second aspect, wherein an alkaline solution containing 1 to 35 wt / vol% of the phenolic polymer compound is quantitatively discharged by a pump and then added to the water to be treated. It is characterized by being diluted with water immediately before being added to the water to be treated.

  According to the present invention, as an aggregating agent for raw water, a phenolic polymer compound having a phenolic hydroxyl group and insoluble in a neutral region and / or high salt (hereinafter simply referred to as “phenolic polymer compound”). Is added to the raw water after diluting, the added phenolic polymer compound is prevented from becoming a membrane-contaminating organic substance or TOC component, and a high water quality membrane having a low MFF value. Supply water can be obtained, thereby preventing membrane contamination, reducing the frequency of chemical cleaning and replacement of the membrane, and enabling stable and efficient membrane separation treatment over a long period of time.

  Hereinafter, embodiments of the present invention will be described in detail.

[Type of raw water]
There is no restriction | limiting in particular as raw | natural water processed by this invention, The various industrial water used for a membrane separation process, the treated water of wastewater, seawater, brine, etc. are mentioned.

[Types of phenolic polymer compounds]
The phenolic polymer compound used in the present invention has a phenolic hydroxyl group, is alkali-soluble, and insolubilizes in the neutral region and / or in the presence of high salts. Specific examples include the following. It is done.

<Phenolic resin>
(1) Condensation product of phenol and formaldehyde (2) Condensation product of cresol and formaldehyde (3) Condensation product of xylenol and formaldehyde (4) Obtained by alkylating the phenolic resin of (1) to (3) above Alkyl-modified phenolic resin

  These phenolic resins may be novolak type, resol type, or a mixture of both. Which phenolic resin is used is selected and used more effectively depending on the type of raw water.

  In addition, it is preferable that the weight average molecular weights (Mw) of a novolak type phenol resin and a resole type phenol resin are 1,000 or more.

<Polyvinylphenol polymer>
(5) Vinylphenol homopolymer (6) Modified vinylphenol homopolymer (7) Vinylphenol and / or copolymer of modified vinylphenol and hydrophobic vinyl monomer

  Examples of the modified vinylphenol (6) include vinylphenols whose phenyl group is chemically modified with some compound, such as vinylphenol substituted with an alkyl group or allyl group, and halogenated vinylphenol.

  Examples of the hydrophobic vinyl monomer (7) include water-insoluble or poorly water-soluble vinyl monomers such as ethylene, acrylonitrile, and methyl methacrylate. The ratio of vinyl phenol and / or modified vinyl phenol in the copolymer of such a hydrophobic vinyl monomer and vinyl phenol and / or modified vinyl phenol is 0.5 or more, particularly 0.7 or more in molar ratio. Preferably there is.

  The vinylphenol polymers (5) to (7) preferably have a weight average molecular weight (Mw) of 1000 or more, for example 1000 to 100,000, and the polymer having such a molecular weight is usually provided as a powder. Is done.

  These phenolic polymer compounds may be used alone or in a combination of two or more.

[Alkaline solution of phenolic polymer compound]
Since the above-mentioned phenolic polymer compound is insoluble or hardly soluble in water, it is provided as a solution or emulsion by dissolving or dispersing in a solvent that can be dissolved in water. Examples of the solvent used include ketones such as acetone, esters such as methyl acetate, water-soluble organic solvents such as alcohols such as methanol, alkaline aqueous solutions, and amines. In the present invention, caustic soda (NaOH), caustic potash (KOH) ) Etc. to make a solution.

  The aqueous alkaline solution of the phenolic polymer compound before dilution is usually prepared with an alkali agent concentration of 3 to 25 wt / wt% and a phenolic polymer compound concentration of 10 to 35 wt / wt%.

[Concentration when phenolic polymer compound is added]
In the present invention, when the water to be treated is seawater or high salt-containing water having an electric conductivity of 1000 mS / m or more, the phenolic polymer compound is added at a concentration of 0.1 wt / vol% in the alkaline solution of the phenolic polymer compound. Dilute to the following and add to treated water. If the concentration of the phenolic polymer compound at the time of adding the alkaline solution of the phenolic polymer compound to the water to be treated exceeds 1 wt / vol%, the above-described effect according to the present invention cannot be obtained.
On the other hand, when the water to be treated has a conductivity of less than 1000 mS / m, the concentration of the phenolic polymer compound at the time of adding the alkaline solution of the phenolic polymer compound may be 1 wt% / vol% or less. The alkaline solution of the phenolic polymer compound is diluted so as to obtain a proper concentration.

In addition, the effectiveness by dilution is remarkable in raw water in which a phenolic polymer compound is likely to precipitate, and is particularly effective in seawater having a high salt concentration or water having a high salt concentration with an electric conductivity of 1000 mS / m or more.
In the case of such raw water having a high salt concentration, the concentration at the time of addition of the phenolic polymer compound is preferably even lower, and the concentration of the phenolic polymer compound in the alkaline solution is 0.1 wt / vol% or less, for example, 0. It is preferable to be about 01 to 0.1 wt / vol%.

  If the salt concentration is not as high as that of seawater and the raw water has an electric conductivity of 300 mS / m or less, the concentration of the phenolic polymer compound in the alkaline solution is about 0.1 to 1.0 wt / vol%. Is preferred.

  In either case, if the concentration of the phenolic polymer compound is high, the above-described effects of the present invention cannot be sufficiently obtained. Conversely, if the concentration is too low, the amount of the diluted aqueous solution of the phenolic polymer compound added increases. It is not preferable.

[Dilution method of phenolic polymer compound]
In order to add the diluted solution as described above to the raw water according to the present invention, a phenolic polymer compound concentration of about 10 to 35 wt / wt% with an alkali agent concentration of 3 to 25 wt / wt% is conventionally used. The alkaline solution of the polymer polymer as it is or once diluted to a phenolic polymer compound concentration of about 3 to 10 wt / vol%, discharged quantitatively with a pump, and further added with the diluted water just before adding to the raw water It is preferable to dilute the polymer compound to a predetermined concentration or less and add it to the raw water. On the other hand, the method of preparing an alkaline solution of a phenolic polymer compound in which a phenolic polymer compound is diluted to a predetermined concentration or less in advance and adding it to raw water requires a large facility for storing and adding the diluted solution. This is not preferable because an insolubilized product is generated in the diluted solution and the aggregation effect is reduced.

  In addition, as described above, it is preferable that the time until the phenolic polymer compound is diluted to a predetermined concentration or less and then added to the raw water is as short as possible, and is preferably several seconds to 10 seconds. If this time is long, an insolubilized product is generated in the diluted solution, and the aggregation effect is reduced, which is not preferable.

  The water used for dilution is preferably water having a low salt concentration, and is preferably water having an electric conductivity of 100 mS / m or less and a pH of 6 or more. Highly salt water such as seawater or acidic water is not preferable because the phenolic polymer compound is associated and precipitated.

[Amount of phenolic polymer compound added]
The amount of phenolic polymer compound added to the raw water varies depending on the quality of the raw water, the type of phenolic polymer compound used, the concentration of the phenolic polymer compound in the alkaline solution, etc. The amount of the polymer polymer added is about 0.1 to 20 mg / L, particularly about 0.3 to 10 mg / L. For example, depending on the concentration in the raw water, the phenol polymer compound and its alkaline solution, the following It is preferable to make it an addition amount.

[Reaction time after addition of phenolic polymer compound]
The time from the addition of the phenolic polymer compound to the raw water to the addition of the inorganic flocculant, that is, the reaction time of the phenolic polymer compound is preferably 1 minute or longer. The reaction time is preferably as long as the capacity of the reaction tank, storage tank, or relay tank is allowed, and is preferably about 5 minutes to 10 hours, for example. In addition, it is preferable to stir the reaction vessel as appropriate, but if the mixing is first performed so that the alkaline solution of the phenolic polymer compound is spread over the entire water to be treated, the subsequent stirring is not necessary.

[Order of addition of phenolic polymer and inorganic flocculant]
In the present invention, an inorganic flocculant is added after adding a phenolic polymer compound to raw water. When a phenolic polymer compound and an inorganic flocculant are added to raw water at the same time, or an inorganic flocculant is added to a location close to the addition location of the phenolic polymer compound, the phenolic polymer compound and the inorganic flocculant As a result of the direct reaction, the effect of adding the phenolic polymer compound cannot be obtained, and the necessary amount of the drug added to compensate for the amount consumed by the reaction increases.
If the phenolic polymer compound is added after the inorganic flocculant, the phenolic polymer compound remains in an unaggregated state, becomes a membrane separation inhibitor, and deteriorates the MFF value.

[Inorganic flocculant]
Examples of inorganic flocculants added after the addition of phenolic polymer compounds include aluminum flocculants such as polyaluminum chloride, aluminum sulfate, and aluminum chloride, and iron such as ferric chloride, ferric sulfate, and polyferric sulfate. A system flocculant can be used. These may be used alone or in combination of two or more.

  The selection of the inorganic flocculant is, for example, an inorganic flocculant that provides the best effect when the inorganic flocculant is added alone to the raw water, and the amount of addition is determined by the MFF value of the flocculated water. It is preferable to make the addition amount that does not improve even if more inorganic flocculants are added, or that only slight improvement can be obtained.

  The amount of the inorganic flocculant added varies depending on the quality of raw water, the type of inorganic flocculant, and the required MFF value, but is usually about 30 to 500 mg / L with respect to the raw water.

[Membrane separation treatment]
In the present invention, the separation membrane used for the membrane separation treatment may be any of MF (precision filtration) membrane, UF (ultrafiltration) membrane, RO (reverse osmosis) membrane, NF (nanofiltration) membrane and the like. The form of the membrane may be any of a flat membrane, a tubular membrane, a hollow fiber, etc., and may be an immersion membrane. Examples of the material of the film include, but are not limited to, PVDF (polyvinylidene fluoride), PE (polyethylene), PP (polypropylene), and the like.

  Hereinafter, the present invention will be described more specifically with reference to experimental examples, examples and comparative examples.

In the following, the following compounds were used as the phenolic polymer compound.
PVF2000: Polyvinylphenol (Mw = 2000)
FR6000: Novolac type phenol resin (Mw = 6000)
FR2000: Novolac type phenolic resin (Mw = 2000)

  As an alkaline solution of the above-described phenolic polymer compound, PVF2000 is used as an 18 wt / wt% aqueous solution of caustic soda, and FR6000 and FR2000 are used as an aqueous solution of 30 wt / wt% caustic soda. Was diluted with pure water to prevent precipitation of the phenolic polymer compound, and the concentration was adjusted for each experiment.

The following inorganic flocculants were used, and commercial products were diluted with pure water to a product concentration of 10 w / v% and used.
FC: Ferric chloride commercial product (FeCl ₃ concentration 38 wt%)
LAC: Liquid aluminum chloride commercial product (Al ₂ O ₃ concentration 10.4 wt%)
LAS: Liquid aluminum sulfate commercial product (Al ₂ (SO ₃ ) ₃ concentration 27 wt%)
PAC: Polyaluminum chloride (Al ₂ O ₃ concentration 10.5 wt%)

[Experimental example 1: Demonstration of effect by addition of low concentration]
Alkaline aqueous solutions of PVF2000, FR6000, and FR2000 were each diluted with pure water to a phenolic polymer compound concentration of 3600 mg / L (0.36 wt / vol%), and 1 ml of this diluted solution was added to the 5.8- Drop and mix in seawater or Nogicho water adjusted to various pH of 9.0, respectively, measure the pH and turbidity so that the concentration of phenolic polymer compound in water is 36 mg / L, The results are shown in FIG. 1 (in the case of seawater) and FIG. 2 (in Nogimachi water).

1 and 2 show the following.
When an alkaline aqueous solution of a phenolic polymer compound is added to seawater, severe turbidity (turbidity = 22 to 30) occurs under the condition of pH 5.8 to 9.0, and the degree is the same regardless of pH. That is, due to the action of high-concentration salts in seawater, the negative charge of the phenolic hydroxyl group that has been dissociated is blocked, the solubility is lost, the phenolic polymer compounds are associated with each other, insolubilized, and turbidity is generated.
In this way, when the raw water is seawater, the phenolic polymer compound added before the active ingredient reacts with the membrane pollutant to be originally acted is bonded to each other, so that improvement of MFF cannot be obtained.

  At this time, if the alkaline solution of the phenolic polymer compound is sufficiently diluted, the density of the phenolic polymer compound is reduced, the probability of association between the phenolic polymer compounds is reduced, and the membrane pollutant is reached and reacts. That is, it is presumed that the membrane contaminant and the phenolic polymer compound can react with each other, and the effect of the present invention can be obtained.

On the other hand, in the case of Nogicho water, any phenolic polymer compound produces turbidity in the neutral range, but the turbidity generation is small and close to zero when the pH is 7.5 to 8.5 or higher.
When the turbidity generation pH is compared, polyvinylphenol (PVF2000) is generated from a higher pH. In the novolak type phenol resin (FR6000, 2000), the higher the molecular weight, the higher the turbidity value and the turbidity generation pH.
However, it is shown that the association and insolubilization of the phenolic polymer compounds occur in the neutral region in any phenolic polymer compound.
This is presumably the reason why the MFF is further improved and the necessary addition amount is reduced when the alkaline solution of the phenolic polymer compound is added at a low concentration.

[Examples and Comparative Examples]
In the following examples and comparative examples, the following experimental methods were used.

<Experiment method>
(1) Raw water is adjusted to 24 ± 2 ° C., 1100 ml thereof is taken into a beaker, and agglomeration is performed by a jar test using MJS-6N manufactured by Miyamoto Seisakusho.
The jar test agitation and reaction conditions were as follows.
-The alkaline solution of the phenolic polymer compound was added with stirring at 150 rpm, and a stirring reaction was performed at 150 rpm for 5 minutes.
The inorganic flocculant was added with stirring at 150 rpm, and rapid stirring for 10 minutes at 150 rpm and slow stirring for 10 minutes at 50 rpm were performed.
-The treatment pH was set to pH 6 or more in the case of an aluminum-based flocculant, and when the pH became less than 6 after the addition of the flocculant, neutralization was performed with a 5 wt / vol% aqueous sodium hydroxide solution so that the pH was approximately 6.1. In the case of an iron-based flocculant, the pH was set to 5 or more. When the pH was less than 5, neutralization was performed with a 5 wt / vol% aqueous sodium hydroxide solution so that the pH was approximately 5.2.
(2) The flocculated water obtained in (1) was allowed to stand for 30 minutes to precipitate the flocculated floc.
(3) The aggregation-treated water of (2) is No. The supernatant was gradually filtered with a 5 (5 μm pore) filter paper, and finally the total amount of the flocculated water was filtered, including the flocculated floc.
(4) 1000 ml or more of the obtained filtrate was placed in two graduated cylinders in 500 ml increments.
(5) Filtrate 500 ml of the filtrate of the first graduated cylinder using a nitrocellulose membrane filter having a pore diameter of 0.45 μm and a diameter of 47 mm manufactured by Millipore under a reduced pressure of 66 kPa (500 mmHg), and the time T1 required for filtration is determined. Measured. Subsequently, another 500 ml of the filtrate of the graduated cylinder was similarly filtered under reduced pressure, the time T2 required for the filtration was measured, and MFF = T2 / T1 was calculated.
The laboratory temperature was adjusted so that the water temperature was 24 ± 2 ° C. at the time of measurement, and the water temperature at the time of measurement was recorded.
The filtration time varies depending on the viscosity coefficient of water, that is, varies depending on the water temperature. However, if measured at the same temperature, T2 / T1 = MFF cancels the temperature effect.
(6) The ultraviolet absorbance (wavelength 260 nm, 50 mm cell) and TOC (total organic carbon) concentration of the remaining filtrate were measured.
The 260 nm ultraviolet absorbance (UV absorbance) is mainly the absorption of organic substances having a C═C double bond, and was measured as a measure of the residual amount of the phenolic polymer compound in the treated water.

[Example I and Comparative Example I (Seawater)]
Seawater (electric conductivity 3400 mS / m, pH 8.38) collected at Jonanjima (Jonanjima Park) in Ota-ku, Tokyo was used as raw water. Ferric chloride (FC) is suitable for this raw water coagulation treatment. When FC was used as the coagulant and the relationship between the FC addition amount and MFF was examined, it was as shown in FIG. 3, and even if the FC addition amount was increased, 1.14 was the limit for MFF. From this result, the FC addition amount in the evaluation of the phenolic polymer compound was set to 80 mg / L. The MFF at this time was 1.158.

Next, by diluting an alkaline solution of a phenolic polymer compound with pure water and adjusting the concentration of each phenolic polymer compound shown in Table 2, the alkali solution of the phenolic polymer compound is shown in Table 2. After adding to the seawater with each phenolic polymer compound addition amount shown, a jar test of adding 80 mg / L of FC was performed, MFF and UV absorbance were measured, and the MFF improvement rate was examined.
These results are shown in Table 2.

Table 2 shows the following.
In Examples I-1 and No. 2, the alkaline solution concentration of the novolak type phenol resin FR2000 is 0.03 wt / vol% (in the table, “w / v%”, the same applies hereinafter), and 0.1 wt / vol% is 1.2 mg. With the addition amount of / L, the MFF was as good as about 1.07, and an MFF improvement rate of 50% or more was obtained with respect to the MFF of ferric chloride alone.
In addition, the MFF improvement rate is obtained by taking the difference (0.092) between the MFF (1.158) when the inorganic flocculant is used alone and the measured MFF value (1.066 in Example I-1) as an improvement value, and this is completely Divide by the difference (0.158) between MFF 1.000 when there is no membrane filtration inhibitor and MFF value when inorganic flocculant alone, and multiply by 100 to give MFF improvement rate (0.092 ÷ 0.158 × 100 = 58 (%)). The same applies to the following.
Moreover, when the concentration in the alkaline solution at the time of FR2000 addition was 0.3 wt / vol%, the MFF improvement rate was 20%, and when 1.0 wt / vol%, the MFF improvement rate was 4%.

Similarly, FR6000 having a large molecular weight has an MFF improvement rate of 50% or more at concentrations of 0.03 wt / vol% and 0.1 wt / vol% in an alkaline solution, but at 0.3 wt / vol% and 1.0 wt / vol%. There was little improvement. Moreover, even if the addition amount was increased to 2.4 mg / L which was doubled at 1.0 wt / vol%, no improvement effect was obtained.
Polyvinylphenol PVF2000 also showed the same results as FR6000.

[Example II and Comparative Example II (sewage treated water)]
Liquid aluminum chloride (LAC) is suitable for agglomeration treatment of A city standard activated sludge sewage treated water (after high-speed filtration, electrical conductivity 58 mS / m). When LAC was used as the aggregating agent and the relationship between the LAC addition amount and MFF was examined, it was as shown in FIG. 4 and even if the LAC addition amount was increased, 1.18 was the limit for MFF. From this result, the LAC addition amount in the evaluation of the phenolic polymer compound was set to 100 mg / L. The MFF at this time was 1.178.

Next, by diluting an alkaline solution of a phenolic polymer compound with pure water and adjusting the concentration of each phenolic polymer compound shown in Table 3, the alkaline solution of the phenolic polymer compound is shown in Table 3. After adding to the sewage-treated water at each phenol-based polymer compound addition amount shown, a jar test was performed in which LAC was added at 100 mg / L, MFF, TOC and UV absorbance were measured, and the MFF improvement rate was examined.
These results are shown in Table 3.

Table 3 shows the following.
In Examples II-1 and 2, when the concentration of the novolak-type phenol resin FR2000 in the alkaline solution is 0.3 wt / vol% and 1 wt / vol%, the MFF is as good as about 1.07 with the addition amount of 2.0 mg / L. Thus, an MFF improvement rate of about 60% was obtained with respect to MFF of liquid aluminum chloride alone.
Further, when the concentration in the alkaline solution when FR2000 was added was 3 wt / vol%, the MFF improvement rate was 19%, and when the concentration was 10 wt / vol%, the MFF improvement rate was 15%.
Similarly, FR6000 having a large molecular weight has an MFF improvement rate of about 70% at a concentration of 0.3 wt / vol% and 1 wt / vol% in an alkaline solution, and an MFF improvement rate of 22 wt% at 10 wt / vol% at 3 wt / vol%. The improvement rate decreased to 11%.
For both FR2000 and FR6000, when the concentration in the alkaline solution is 10 wt / vol%, the addition rate must be about three times to obtain the same effect as the concentration in the alkaline solution of 0.3 to 1.0 wt / vol%. It was.
As a result, both the UV absorbance and TOC of the agglomerated / filtered water increased as the amount added increased.

Polyvinylphenol PVF2000 also has an MFF improvement rate of about 70% at a concentration of 0.3 to 1.0 wt / vol% in an alkaline solution and an addition rate of 2.0 mg / L, but an MFF improvement rate of 3 to 10 wt / vol%. It decreased to 19-12%.
In order to obtain the same effect as in the case of the concentration of 0.3 to 1 wt / vol% when the concentration in the alkaline solution is 10 wt / vol%, about 3 times as much addition amount was required as in FR2000 and FR6000.

[Example III and Comparative Example III (biological carrier method treated water)]
Liquid aluminum sulfate (LAS) is suitable for the agglomeration treatment of B factory wastewater biological carrier method treated water (after high-speed filtration, electrical conductivity 104 mS / m). When LAS was used as a flocculant and the relationship between LAS addition amount and MFF was examined, it was as shown in FIG. 5. Even if the LAS addition amount was increased, MFF was 1.30 at the limit, and membrane contamination that could not be removed with inorganic flocculant It was water with a lot of substance.
Therefore, the LAS addition amount in the evaluation of the phenolic polymer compound was set to 318 mg / L. The MFF at this time was 1.322.

Next, by diluting an alkaline solution of a phenolic polymer compound with pure water to adjust the concentration of each phenolic polymer compound shown in Table 4, the alkali solution of the phenolic polymer compound is shown in Table 4. After adding to the biological carrier method treated water at each phenolic polymer compound addition amount shown, a jar test was performed in which 318 mg / L of LAS was added, MFF, TOC and UV absorbance were measured, and the MFF improvement rate was examined.
These results are shown in Table 4.

Table 4 shows the following.
In Examples III-1 and II, when the concentration of the novolak-type phenol resin FR2000 in the alkaline solution is 0.3 wt / vol% and 1 wt / vol%, the MFF is as good as about 1.1 with an addition amount of 5.0 mg / L. Thus, an MFF improvement rate of about 70% was obtained with respect to MFF of liquid aluminum sulfate alone.
When the concentration in the alkaline solution at the time of addition was 3 wt / vol%, the MFF improvement rate was 42%, and when it was 10 wt / vol%, the MFF improvement rate was 37%.

Similarly, FR6000 having a large molecular weight can obtain an MFF improvement rate of about 70% at concentrations of 0.3 wt / vol% and 1 wt / vol% in an alkaline solution, and an MFF improvement rate of 40% and 10 wt / vol% at 3 wt / vol%. Decreased to 30%.
For both FR2000 and FR6000, when the concentration in the alkaline solution is 10 wt / vol%, the addition rate needs to be about 2 to 3 times to obtain the same effect as the concentration in the alkaline solution of 0.3 to 1.0 wt / vol%. there were.
As a result, both the UV absorbance and TOC of the agglomerated / filtered water increased greatly as the addition amount increased.

Polyvinylphenol PVF2000 also has an MFF improvement rate of 60-70% at an alkali solution concentration of 0.3-1.0 wt / vol% and an addition rate of 5.0 mg / L, but an alkali solution concentration of 3-10 wt / vol. %, The MFF improvement rate decreased to 37 to 25%.
In order to obtain the same effect as the concentration of 0.3 to 1 wt / vol% when the concentration in the alkaline solution was 10 wt / vol%, about 3 times the addition amount was required.

[Example IV and Comparative Example IV (C city industrial water)]
Polyaluminum chloride (PAC) is suitable for the agglomeration treatment of C city industrial water (electric conductivity 26 mS / m). When PAC was used as an aggregating agent and the relationship between the PAC addition amount and MFF was examined, it was as shown in FIG. 6, and MFF 1.10. Was obtained at a PAC addition amount of 45 mg / L. However, no improvement in MFF was observed even when the amount added was further increased.
Therefore, the amount of PAC added in the evaluation of the phenolic polymer compound was set to 45 mg / L. The MFF at this time was 1.097.

Next, by diluting an alkaline solution of a phenolic polymer compound with pure water and adjusting the concentration of each phenolic polymer compound shown in Table 5, the alkaline solution of the phenolic polymer compound is shown in Table 5. After adding to the industrial water at the amount of each phenolic polymer compound shown, a jar test of adding 45 mg / L of PAC was performed, and MFF, TOC and UV absorbance measurements were performed to examine the MFF improvement rate.
These results are shown in Table 5.

Table 5 shows the following.
In Examples IV-1 and 2, when the concentration of the novolak-type phenol resin FR2000 in the alkaline solution is 0.3 wt / vol% and 1 wt / vol%, the MFF is very low at 1.05 or less with an addition amount of 0.3 mg / L. The MFF improvement rate was 50% or more with respect to MFF of polyaluminum chloride alone.
In this example, the required addition amount of the phenolic polymer compound is considerably less, from 1/5 to 1/10, compared to sewage treated water or factory wastewater biological carrier treated water. This is presumably because the absolute amount of membrane contaminants is considerably less than the previous two types of water since the amount of inorganic flocculant PAC alone added is small and the achieved MFF is also quite good at 1.0.
When the concentration in the alkaline solution when FR2000 was added was 3 wt / vol%, the MFF improvement rate was 32%, and when the concentration was 10 wt / vol%, the MFF improvement rate was reduced to 26%.

Similarly, FR6000 having a large molecular weight also has an MFF improvement rate of 50% or more at an alkali solution concentration of 0.3 wt / vol%, 1 wt / vol%, an MFF improvement rate of 27% at 3 wt / vol%, and an MFF at 10 wt / vol%. The improvement rate decreased to 21%.
For both FR2000 and FR6000, when the concentration in the alkali solution was 10 wt / vol%, the addition rate had to be about 3 times to obtain the same effect as the concentration in the alkali solution of 0.3 to 1.0 wt / vol%. .

  In the novolak type phenol resin, a part of the resin component remains in the treated water after flocculation and filtration, but by adding the concentration in the alkaline solution to 1 wt / vol% or less, a very small addition amount of 0.3 mg / L Can sufficiently improve the membrane filterability, and as a result, the TOC in the treated water can be prevented from rising.

Polyvinylphenol PVF2000 also has an MFF improvement rate of about 45% at a concentration of 0.3 to 1.0 wt / vol% in an alkaline solution and an addition rate of 0.3 mg / L, and an MFF improvement rate of 3 to 10 wt / vol%. Decreased to 24-20%.
In addition, when the concentration in the alkaline solution was 10 wt / vol%, about 3 times the addition amount was required to obtain the same effect as the concentration of 0.3 to 1 wt / vol%.

The following can be understood from the results of the above Examples and Comparative Examples.
(1) In the agglomeration treatment performed prior to the membrane separation treatment, an alkaline solution of a phenolic polymer compound is added as a diluted solution having a phenolic polymer compound concentration of 1 wt / vol% or less, and an inorganic flocculant is further added. By performing the flocculation treatment, the MFF, which is a membrane filterability index of the treated water, can be improved by 50% or more from the achieved value of the inorganic flocculant alone.
When the concentration in the alkaline solution at the time of adding the phenolic polymer compound is 10 wt / vol%, the necessary addition amount for obtaining the same membrane filterability improvement rate is 3 to 2 times.
According to the present invention, the amount of the phenolic polymer compound added necessary for improving the membrane filterability can be greatly reduced, so that the processing cost can be greatly reduced.

In addition, among the phenolic polymer compounds, the novolak phenol resin alkaline solution has a resin component remaining on the agglomerated treated water side, and if the amount added is large, the treated water TOC is increased. Although it was regarded as inappropriate, by adding it as a dilute solution according to the present invention, it was possible to demonstrate effectiveness as a flocculant, particularly as a pretreatment for membrane separation treatment, by reducing the required addition rate.
In addition, in the agglomeration treatment as a pretreatment for the seawater membrane separation treatment, the concentration of the phenol-based polymer compound alkali solution is added as a more dilute solution having a concentration of 0.1 wt / vol% or less, thereby agglomerating the inorganic flocculant alone. The membrane filterability index MFF was improved by 50 to 60% with respect to the case of the treatment.
When the concentration of the phenolic polymer compound alkaline solution exceeded 1 wt / vol%, the MFF value could hardly be improved even when the addition amount was increased.

It is a graph which shows the relationship between the pH of the seawater in Experimental example 1, and the turbidity at the time of phenol-type high molecular compound addition. It is a graph which shows the relationship between the pH of Nogi-cho water in Experimental Example 1, and the turbidity at the time of phenolic polymer compound addition. It is a graph which shows the relationship between FC addition amount and MFF in Experimental example I and Comparative example I. It is a graph which shows the relationship between LAC addition amount and MFF in Experimental example II and Comparative example II. It is a graph which shows the relationship between the LAS addition amount and MFF in Experimental example III and Comparative example III. It is a graph which shows the relationship between PAC addition amount and MFF in Experimental Example IV and Comparative Example IV.

Claims (3)

After adding an alkaline solution of a phenolic polymer compound to seawater or water to be treated which is high salt-containing water having an electric conductivity of 1000 mS / m or more, an inorganic flocculant is added to perform agglomeration, and the agglomerated water is solidified. In the method of liquid separation and membrane separation treatment of the separated water obtained,
The phenol-based polymer compound is an alkali-soluble polymer compound having a phenolic hydroxyl group and insolubilized in the presence of a neutral region and / or a high salt, and the polymer compound has a polymer compound concentration of 0.1 wt / vol. A membrane separation treatment method, comprising adding to the water to be treated as an alkaline solution of not more than%. Separation obtained by adding an alkaline solution of a phenolic polymer compound to water to be treated having an electrical conductivity of less than 1000 mS / m, adding an inorganic flocculant to agglomerate, and subjecting the agglomerated water to solid-liquid separation. In a method for separating water from a membrane,
The phenolic polymer compound is an alkali-soluble polymer compound having a phenolic hydroxyl group and insoluble in the presence of a neutral region and / or a high salt, and the polymer compound has a polymer compound concentration of 1 wt / vol% or less. A membrane separation treatment method characterized by adding to the water to be treated as an alkaline solution.   3. The alkaline solution containing 1 to 35 wt / vol% of the phenolic polymer compound according to claim 1 or 2, after being quantitatively discharged by a pump, diluted with water immediately before being added to the treated water. A membrane separation treatment method comprising adding to water.

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