JP5106182B2 - Water treatment method and water treatment apparatus - Google Patents

Description

  The present invention relates to a water treatment method and a water treatment apparatus for treating development waste liquid-containing raw water discharged from an electronic industry such as a semiconductor production process or a liquid crystal panel production process by a submerged membrane activated sludge treatment.

  In recent years, large quantities of production water, pure water, ultrapure water, etc. have been used in electronic manufacturing factories such as semiconductor manufacturing processes and liquid crystal panel manufacturing factories, chemical factories, automobile factories, etc., limiting the intake of industrial water and securing water resources Consideration is being made to collect and reuse wastewater in the factory due to the environmental impact on the wastewater discharge destination and soaring sewage charges.

  Currently, as a wastewater recovery process in the above-mentioned factory, there is an increasing number of cases where water is recovered and reused by performing reverse osmosis membrane (RO membrane) treatment after biological treatment. In this treatment method, RO due to microorganisms or metabolites is increasing. The problem is that the film is clogged quickly and the flux is rapidly reduced (see, for example, Patent Document 1). When the RO membrane is clogged, it is necessary to frequently perform alkali cleaning or the like, which is a big problem in terms of operation management and running cost. In view of this, a method of operating RO membrane water with alkali has been proposed (see Patent Document 2). However, the running cost is always increased by performing alkaline operation, the life of RO membrane, and even in this method, chemicals are used. It is necessary to perform cleaning, which is an operational issue.

  On the other hand, TMAH (tetramethylammonium hydroxide) development waste liquid processing methods and wastewater recovery processing methods that contain some resist-derived resins have been proposed as various methods (biological processing, ion exchange resins, membrane processing, etc.). (See Patent Documents 3 to 6).

  In the above background, studies have started to use the activated sludge treatment of submerged membrane for wastewater collection in the factory, and as a result of studying the application using various simulated wastewater and actual wastewater, depending on the wastewater, clogging of the submerged membrane may occur. A phenomenon that is noticeably faster was observed.

  Therefore, the present inventors diligently investigated the cause of clogging of the submerged membrane with respect to sludge properties, sludge viscosity, operating conditions such as sludge load, and components contained in raw water. As a result, turbidity contained in actual wastewater may have a greater effect on the clogging of the submerged membrane than the state of activated sludge and the type and concentration of organic matter in the raw water based on comparative evaluation of simulated wastewater and actual wastewater. I found. Although the detailed mechanism of the clogging of the submerged membrane is unknown, it is presumed to be a resist-derived resin contained in the actual waste water, as well as a turbidity derived from a pigment or a dye system.

  In addition, it was speculated that the raw water for wastewater collection also contains a part of the development wastewater and contained turbidity derived from the resist resin. Membrane treatment and ion exchange treatment are also carried out in the wastewater treatment, and in this case, there is a problem in the application of submerged membrane activated sludge treatment because it is mixed and diluted several tens of times with other types of wastewater. It has never been considered.

  In the conventional treatment of the resist resin-containing raw water, it is conceivable to deposit the resist resin before the film treatment, but in this method, the stability of operation due to clogging of the deposited SS with the film is recognized as a major problem. Not. Although it has been proposed to use a vibration-type membrane to prevent contamination of the membrane surface, installation of the vibration-type membrane treatment is not a practical method in terms of scale and economy in high-flow rate processing. .

  If the submerged membrane becomes clogged, in-line cleaning is performed by injecting hypochlorous acid or the like while immersed in activated sludge, or the submerged membrane is taken out from the biological reaction tank and immersed in hypochlorous acid or citric acid. It is necessary to wash. The timing of chemical cleaning is generally performed when the differential pressure of the suction pressure of the immersion film reaches about 30 to 50 kPa, and the frequency is at least 3 months or more, preferably 6 months to 1 Once a year is preferable for operation.

JP 2002-336886 A JP 2005-81268 A Japanese Patent Publication No. 8-235 JP 2001-276825 A Japanese Patent No. 2730610 JP-A-11-262765

  In the water treatment by the immersion membrane activated sludge treatment, the present invention does not cause the clogging of the immersion membrane, and the RO membrane clogging does not occur abruptly when the treatment with the RO membrane is performed later, Alternatively, a water treatment method and a water treatment apparatus capable of stably performing water recovery are provided.

The present invention is a water treatment method including a submerged membrane activated sludge treatment step in which a development waste liquid-containing raw water containing a resist resin is subjected to a activated sludge treatment using a submerged membrane, before the submerged membrane activated sludge treatment step. The water treatment method includes a coagulation separation process step of adding a polymer flocculant after adjusting the pH of the developing waste liquid-containing raw water to a range of 5.5 to 7, adding an inorganic flocculant .

  Moreover, in the said water treatment method, it is preferable that pH in the said activated sludge process is the range of 5.5-7.

  In the water treatment method, it is preferable that the agglomeration separation process is an agglomeration pressure flotation process.

  Moreover, it is preferable that the water treatment method includes a reverse osmosis membrane treatment step of separating the biologically treated water subjected to the activated sludge treatment using a reverse osmosis membrane.

Further, the present invention is a water treatment apparatus comprising an immersion sludge activated sludge treatment means for performing development sludge treatment containing raw water containing a resist resin using an immersion membrane, wherein the immersion membrane activated sludge treatment means It is a water treatment apparatus provided with a flocculation separation processing means for adding a polymer flocculant after adjusting the pH of the development waste liquid-containing raw water to a range of 5.5 to 7 and adding an inorganic flocculant .

  Moreover, it is preferable that the said water treatment apparatus is equipped with the pH adjustment means for adjusting pH in the said coagulation separation process.

  Moreover, in the water treatment apparatus, it is preferable that the coagulation separation treatment unit has a pressure levitation treatment unit.

  The water treatment apparatus preferably includes a reverse osmosis membrane treatment means having a reverse osmosis membrane downstream of the immersion membrane activated sludge treatment means.

  In the present invention, the immersion membrane activated sludge treatment is carried out after the coagulation / separation treatment, so that the immersion membrane is clogged, and the RO membrane clogging does not occur abruptly when the treatment with the RO membrane is performed later, and the developer waste liquid is contained. The raw water can be stably treated or recovered.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  The present inventors use simulated wastewater discharged from a liquid crystal panel factory and actual wastewater (including the suspended solids (SS) generated from the manufacturing process, which have the same composition as the simulated wastewater), but the performance, immersion The film was evaluated for clogging. As a result, it became clear that the membrane clogging of the actual waste water was more remarkable than the simulated waste water. Then, as a result of retesting SS contained in the actual wastewater after the coagulation separation treatment, it was found that the membrane differential pressure could be suppressed to the same level as when simulated drainage water was passed. The flocculation conditions were also intensively investigated, and the flocculation conditions that could reliably perform solid-liquid separation with little influence on the performance of the subsequent biological treatment were found. If it is this condition, it will become possible to save the pH adjustment for biological treatment again after aggregating-separation process, and to suppress clogging of a submerged membrane.

  An example of a water treatment apparatus according to an embodiment of the present invention is schematically shown in FIG. The water treatment apparatus 1 includes a raw water tank 10, an inorganic flocculation reaction tank 12, which is a flocculation separation processing means, a polymer flocculation reaction tank 14, a flocculation solid-liquid separation apparatus 16 as a flocculation solid-liquid separation means, and a flocculation treatment water tank 18. And an RO membrane which is a reverse osmosis membrane treatment means having a biological reaction tank 20 which is an immersion membrane activated sludge treatment means, an immersion membrane unit 22 provided with an immersion membrane, a biological treatment water tank 24, and a reverse osmosis membrane (RO membrane). And a separation device 26.

  In the water treatment apparatus 1 of FIG. 1, the outlet of the raw water tank 10 is the inlet of the inorganic agglomeration reaction tank 12 by the raw water pipe 28, and the outlet of the inorganic agglomeration reaction tank 12 is the inlet of the polymer agglomeration reaction tank 14 by the inorganic agglomeration water pipe 30. The outlet of the polymer flocculation reaction tank 14 is connected to the inlet of the flocculated solid / liquid separator 16 by the polymer flocculated water pipe 32, and the outlet of the flocculated solid / liquid separator 16 is connected to the inlet of the flocculated water tank 18 by the flocculated water pipe 34. , Each connected. The outlet of the flocculation water tank 18 is connected to the lower part of the biological reaction tank 20 through the pump 36 through the flocculation water pipe 38. An immersion membrane unit 22 is installed in the biological reaction tank 20, and the immersion film of the immersion membrane unit 22 is connected to the biological treatment water tank 24 by a biological treatment water pipe 42 via a suction pump 40. The outlet of the biological treatment water tank 24 is connected to the inlet of the RO membrane separation device 26 through a filter 44 and a pump 46 through a biological treatment water pipe 48. A treated water pipe 50 is connected to the outlet of the RO membrane separator 26. Moreover, the lower part of the biologically treated water tank 24 is connected to the downstream side of the suction pump 40 in the middle of the biologically treated water pipe 42 by a backwash pipe 54 via a backwash pump 52 that is a backwash means, if necessary. Also good. A compressor 56 serving as aeration means is connected to the bottom of the biological reaction tank 20 via an aeration pipe 58.

  The operation of the water treatment method and the water treatment apparatus 1 according to this embodiment will be described.

<Aggregation separation process>
In the water treatment apparatus 1 of FIG. 1, development waste liquid-containing raw water (hereinafter sometimes simply referred to as “raw water”) flows into the raw water tank 10 and then is sent to the inorganic agglomeration reaction tank 12 through the raw water pipe 28. . In the inorganic agglomeration reaction tank 12, an inorganic aggregating agent is added, and an inorganic agglutination reaction such as a resin derived from a resist is performed (inorganic agglomeration reaction step). In the inorganic agglomeration reaction tank 12, it is preferable to adjust the pH in the agglomeration separation process by adding a pH adjusting agent by a pump which is a pH adjusting means (not shown). Thereafter, the inorganic agglomerated water subjected to the inorganic agglomeration treatment is sent to the polymer agglomeration reaction tank 14 through the inorganic agglomerated water pipe 30. In the polymer agglomeration reaction tank 14, a polymer aggregating agent is added and a polymer agglutination reaction is performed (polymer agglutination reaction step). The polymer agglomerated water subjected to the polymer agglomeration treatment is sent to the agglomerated solid-liquid separator 16 through the polymer agglomerated water pipe 32, and the agglomerated solid-liquid separator 16 performs the agglomerated solid-liquid separation process. Water is obtained (aggregated solid-liquid separation process). In the coagulation solid-liquid separation treatment step, it is preferable that solid-liquid separation is performed by a pressure flotation device that is a pressure flotation treatment means.

<Immersion membrane activated sludge treatment process>
The agglomerated water is sent to the biological reaction tank 20 through the agglomerated water pipe 38 by the pump 36. In the biological reaction tank 20, aerobic activated sludge exists. On the other hand, air from the compressor 56 is sent from the bottom of the biological reaction tank 20 through the aeration pipe 58. In the biological reaction tank 20, the organic matter in the raw water is decomposed by the activated sludge (immersion membrane activated sludge treatment step). The immersion membrane of the immersion membrane unit 22 is sucked by the suction pump 40, and solid-liquid separation is performed (solid-liquid separation step). The biologically treated water subjected to solid-liquid separation is sent to the biologically treated water tank 24 through the biologically treated water pipe 42. As necessary, at least a part of the biologically treated water in the biologically treated water tank 24 is backwashed at a predetermined interval, and the backwash pump 52 immerses the submerged membrane unit 22 through the backwash pipe 54 and the biologically treated water pipe 42. The liquid may be fed to the membrane and the immersion membrane may be backwashed.

<Reverse osmosis membrane treatment process>
When the biologically treated water is collected and reused, the liquid is further sent to the RO membrane separation device 26 through the biological treatment water pipe 48 via the filter 44 by the pump 46. Membrane treatment is performed (reverse osmosis membrane treatment step). The treated water subjected to the RO membrane treatment is discharged out of the system through the treated water pipe 50.

<Applicable raw water>
In this embodiment, the applicable TOC concentration of developing waste liquid-containing raw water is, for example, 2000 mgC / L or less, and the BOD concentration is, for example, 500 mg / L or less for water recovery. For example, other than for water recovery, the TOC concentration is 1500 mgC / L or less and the BOD concentration is 3000 mg / L or less.

  Applicable raw water is, for example, wastewater containing SS such as resist resin discharged from semiconductor factories, liquid crystal panel factories, and other factories (usually precipitated under pH neutral conditions and dissolved under alkaline conditions). . The main components contained in these wastewaters include 2-aminoethanol, 2-propanol, TMAH (tetramethylammonium hydroxide), choline, DMSO (dimethylsulfoxide), N-methyl-2-pyrrolidone, acetic acid, There are organic acids such as oxalic acid and surfactants, but the components are not limited to these substances. It is suitable mainly for waste water containing a development waste liquid containing a resist resin from a process using a resist such as a photoresist. The resist resin is not particularly limited as long as it is a resin used for a resist such as a photoresist. As a kind of the photoresist, there are a positive type photoresist in which the exposed portion is soluble (etched) in the developer and a negative photoresist in which the exposed portion is insoluble in the developer.

<Aggregation separation processing conditions>
The inorganic agglomeration treatment can be performed at a concentration of about 50 to 500 mg / L using an inorganic aggregating agent such as polyaluminum chloride (PAC) used for ordinary agglomeration treatment.

  The polymer flocculation treatment can be performed at a concentration of about 1 to 10 mg / L using a polymer flocculating agent such as an anionic polymer used in ordinary flocculation treatment.

  The pH in the flocculation treatment (inorganic flocculation reaction step, polymer flocculation reaction step) is usually in the range of 5.5 to 8.0, but in this method, the pH is 5.5 to 7 which is slightly less acidic than usual. The range is preferable, and the range of 6 to 6.5 is more preferable. The aggregation state tends to be good in the range of pH 5.5-7. This is probably because the resist is acidic and more likely to precipitate. If it is this range, it will become possible to save labor to perform pH adjustment for activated sludge processing again after coagulation separation processing.

  As the pH adjusting agent, an acid such as hydrochloric acid or an alkali such as caustic soda can be used.

  As the agglomerated solid-liquid separation means after the agglomeration treatment, a sedimentation basin, a pressurized flotation treatment, a membrane treatment, and the like can be used.

<Immersion membrane activated sludge treatment conditions>
As the treatment conditions of the biological reaction tank 20 in the immersion membrane activated sludge treatment, the sludge concentration is 10,000 mg / L or less, preferably in the range of 3,000 to 8,000 mg / L, and the sludge viscosity is 60 mPa · s or less, preferably Is preferably operated in a range of 50 mPa · s or less and a load of the biological reaction tank 20 of 1.5 kg BOD / m ³ / day or less, preferably 0.4 to 1.0 kg BOD / m ³ / day.

If the sludge concentration exceeds 10,000 mg / L, the viscosity of the sludge increases rapidly and the immersion membrane may be clogged. If it is less than 3,000 mg / L, the BOD load per sludge increases and the quality of the treated water It may get worse. If the sludge viscosity exceeds 60 mPa · s, the viscosity of the sludge increases rapidly and the immersion film may be clogged. Moreover, when the load of the biological reaction tank 20 exceeds 1.5 kgBOD / m ³ / day, the quality of the treated water may be deteriorated and the immersion film may be clogged, and the immersion film is less than 0.4 kgBOD / m ³ / day. Clogging may occur, and the biological reaction tank may be greatly uneconomical.

  The residence time in the biological reaction tank 20 is in the range of 1 hour to 24 hours, and preferably in the range of 2 to 5 hours. If the residence time is less than 1 hour, the treatment cannot be performed sufficiently. If it exceeds 24 hours, the processing cost increases. In addition, flocs are dispersed.

  About the sludge load (BOD-SS load) in the biological reaction tank 20, the range of 0.005-0.15kgBOD / SS / day is preferable. If the sludge load is less than 0.005 kg BOD / SS / day, the sludge may be in a dispersed state due to a low load and the immersion membrane may be clogged. If the sludge load exceeds 0.15 kg BOD / SS / day, the treated water quality deteriorates due to the high load. In addition, the immersion membrane may be clogged due to an increase in bacterial metabolites.

  It is preferable to adjust the pH of the liquid in the biological reaction tank 20 to be in the range of 5.5 to 7, particularly in the range of 5.5 to 6.5. When the pH is in the range of 5.5 to 7, the resist remaining in the agglomerated water can be easily deposited and taken into the sludge, and biological treatment is possible. When the pH is less than 5.5 or exceeds 7, biological treatment performance may be deteriorated. As described above, the pH of the liquid in the biological reaction tank 20 is maintained in the range of 5.5 to 7 by adjusting the pH in the aggregation treatment to the range of 5.5 to 7, but if necessary, You may adjust pH by adding a pH adjuster.

  The DO (dissolved oxygen) concentration in the biological reaction tank 20 is preferably 0.5 mg / L or more, particularly preferably in the range of 1.5 to 3.5 mg / L. When the DO concentration is less than 0.5 mg / L, the biological treatment performance may be deteriorated, and when it exceeds 3.5 mg / L, flocs are dispersed, and the processing cost increases, which may be uneconomical. is there.

  As nutrient sources in the biological reaction tank 20, in order for microorganisms to decompose and grow organic matter, in addition to nitrogen and phosphorus, alkali metals such as sodium, potassium, calcium and magnesium, iron, manganese, zinc, etc. Trace metals such as these metals are required. As the nitrogen source, urea, ammonia salt or the like can be added from the outside. As the phosphorus source, phosphate and phosphoric acid can be added from the outside. Moreover, as a nitrogen source / phosphorus source, it is not necessary to add from the outside if the raw water contains a sufficient amount, and it is also possible to add other waste water containing nitrogen / phosphorus to the organic material-containing raw water. Can do. Trace metals are often deficient in organic material-containing raw water at semiconductor factories and liquid crystal panel factories. For this reason, it can be replenished by a method such as introducing water containing trace metals such as tap water or industrial water, or adding a preparation containing trace elements.

<Immersion film>
The immersion membrane can be immersed in the biological reaction tank 20 and biologically treated water can be obtained by suction filtration of the immersion film. A separate membrane separation tank is provided after the biological reaction tank 20, and the immersion membrane is immersed therein. You can also In this embodiment, it is preferable to use a form that can be backwashed regularly, typically a hollow fiber membrane, a tubular membrane, or the like, but a flat membrane or the like can also be used. The flat membrane is difficult to backwash because there is a risk of damage to the edges. As the immersion membrane, a microfiltration membrane or an ultrafiltration membrane can be used. As the material of the immersion film, for example, fluororesin such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), etc. can be applied. PVDF is preferred. The pore diameter of the membrane is preferably 0.4 μm or less, particularly preferably 0.1 μm or less. The membrane can be operated at a permeation flow rate of about 0.1 to 0.8 m / hr, more preferably 0.2 to 0.6 m / hr.

<RO membrane>
As RO membranes, polyether amide composite membranes, polyvinyl alcohol composite membranes, aromatic polyamide membranes, etc. can be used, membranes that are neutrally charged on the surface of membranes that are considered to be less susceptible to contamination by surfactants and trace organics (For example, LF-10 manufactured by Nitto Denko) and ultra-low pressure type membranes (for example, ES-10 manufactured by Nitto Denko) that can be operated at a lower operating pressure than conventional low-pressure RO membranes are preferable. The module shape of these RO membranes can be any shape such as a spiral type, a hollow fiber type, and a tubular type.

  Further, when the development waste liquid-containing raw water contains a nonionic surfactant, polyethylene glycol, etc., the RO membrane is likely to be clogged. In such a case, the upstream side of the RO membrane separation device 26 (for example, a filter) It is preferable to install an activated carbon treatment apparatus, which is an activated carbon treatment means, in the preceding stage of 44. Further, it is preferable to install a filter 44 having a pore diameter of about 10 μm as a pretreatment of the RO membrane.

  In the case where there is a possibility that scale is generated due to an inorganic component such as calcium, it is preferable to install a dispersing agent adding means or a softening device in the RO membrane separation device 26. Furthermore, for the purpose of preventing clogging due to generation of slime caused by microorganisms in long-term operation, addition of a slime control agent (isothiazoline-based, organic bromine-based, etc.), application of acid shock by sulfuric acid, alkaline operation (pH 9. 5 or more).

  The treated water can be reused as cooling water for factories or the like, water for production, pure water, ultrapure water, or the like.

  A higher water recovery rate is economically preferable, but it is preferable to operate at 50 to 90%, preferably 65 to 75%, as an organic wastewater recovery system that enables stable operation.

  As described above, the present inventors generate suction pressure in a very short time when applying submerged membrane activated sludge for treatment and recovery of raw water containing developer waste liquid such as liquid crystal panel factories, for which demand is increasing in recent years. Therefore, the problem that it cannot be put into practical use was clarified. On the other hand, the water treatment method and the water treatment apparatus according to the present embodiment perform the immersion membrane activated sludge treatment after the coagulation separation treatment, thereby solving the increase in cost due to operation management, chemical cleaning, etc. Management is easy, and stable operation of the immersion membrane activated sludge treatment of the developing waste liquid-containing raw water and stable operation including the subsequent RO treatment are possible. Therefore, it becomes an effective method especially in the wastewater recovery system combined with the RO membrane. In the future, water treatment and recovery of raw water containing developer wastewater will be highly desired from the viewpoint of securing water resources and draining water, including in Japan and overseas, and the water treatment method and water treatment apparatus according to this embodiment will be very It is considered useful.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

(Example 1, Comparative Examples 1 and 2)
An evaluation of immersion membrane application for raw water containing developer wastewater was conducted using actual wastewater and simulated wastewater. For the test, PVDF hollow fiber type immersion membranes were used to evaluate the suction pressure of the immersion membrane, the quality of the treated water, and clogging of the downstream RO membrane. The experimental apparatus used is shown in FIG.

<Water flow conditions>
Raw water: Simulated wastewater from electronic industry factory, and actual wastewater TOC concentration 80mgC / L (Rawwater BOD concentration: 200mg / L)
Example 1: Use the water from which the actual wastewater was agglomerated under the following conditions and then separated SS by pressurized flotation. (Agglomeration conditions) After adding PAC 100 mg / L to the raw water, the pH was adjusted to 6.0 ± 0.2. Anion polymer (manufactured by Organo Co., Ltd., OA-23) 1 mg / L added to agglomerate Comparative Example 1: Simulated wastewater having the same substrate and composition as actual wastewater (not including resist-derived SS)
Comparative Example 2: Actual drainage (SS30mg / L of raw water)
Water flow rate: 17L / day

<Experimental equipment>
The biological reaction tank (MBR tank), the immersion membrane unit, and the RO membrane were implemented using the following experimental apparatus.
[Bioreaction tank]
Biological reaction tank capacity: 1L
Membrane separation tank capacity: 2.5L
pH: Control around 6 Water temperature: 20-22 ° C
Residence time: 4.9 hours Sludge concentration (MLSS): 7,000 to 8,000 mg / L
BOD-SS load: 0.10 to 0.12 kg BOD / kgSS / day
DO: 1-2 mg O / L
Air supply volume: 0.5L / min
[Immersion membrane unit]
PVDF hollow fiber type immersion membrane (Asahi Kasei, pore size 0.1 μm)
Immersion film flux: 0.6 m / day
[RO membrane]
Membrane: Nitto Denko LF-10 70% water recovery

<Result>
FIG. 3 shows the suction pressure of the submerged membrane when implemented under each condition. From the results of Comparative Example 1 and Comparative Example 2, it was found that although the dissolved substrates were equivalent, the increase in the suction pressure of the membrane was significantly different. In Comparative Example 2 using actual waste water, it was found that it was difficult to put it to practical use because it reached a differential pressure of 30 kPa, which required chemical cleaning in 3 days, with a flux of 0.6 m / day that was normally put into practical use. On the other hand, in Example 1 using the water which carried out the aggregation process of SS contained in a real waste_water | drain, the raise of the suction pressure was suppressed and it confirmed that it stabilized.

  FIG. 4 shows the results of absorbance obtained by wavelength scanning of the actual waste water used in Example 1 and the agglomerated water after agglomeration separation. A peak near a wavelength of 290 nm (see Japanese Patent Application Laid-Open No. 2001-212596) characteristic of the resist is seen in the raw water, but it can be seen that it is greatly reduced after the aggregation treatment. The absorbance was measured after adjusting the pH to 12 in order to dissolve the resin.

  At this time, the quality of the treated water under each condition of Example 1 and Comparative Example 2 was good in any system.

  In addition, a water flow test of the treated water of Example 1 to the RO membrane was also conducted, and it was confirmed that the quality of the treated water was 0.9 mg C / L and the RO membrane flux was stable. Has been confirmed to be particularly effective in collecting wastewater from electronic industry factories.

  As described above, it has become possible to stably recover water discharged from the electronics industry.

It is a schematic structure figure showing an example of the water treatment equipment concerning the embodiment of the present invention. It is a schematic block diagram which shows the water treatment apparatus used in the Example of this invention. It is a graph which shows the suction pressure change of an immersion film in the Example of this invention. It is a graph which shows the light absorbency used in Example 1 of this invention, and the light absorbency of the aggregation process water after aggregation separation.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Water treatment apparatus, 10 Raw water tank, 12 Inorganic aggregation reaction tank, 14 Polymer aggregation reaction tank, 16 Aggregation solid-liquid separation apparatus, 18 Aggregation treatment water tank, 20 Biological reaction tank, 22 Immersion membrane unit, 24 Biological treatment water tank, 26 RO membrane separator, 28 raw water piping, 30 inorganic flocculated water piping, 32 polymer flocculated water piping, 34, 38 flocculated water piping, 36, 46 pump, 40 suction pump, 42, 48 biologically treated water piping, 44 filter, 50 treated water piping, 52 backwash pump, 54 backwash piping, 56 compressor, 58 aeration piping.

Claims (8)

It is a water treatment method including an immersion sludge activated sludge treatment step in which a development waste liquid-containing raw water containing a resist resin is subjected to activated sludge treatment using an immersion membrane,
Before the immersion membrane activated sludge treatment step, adjusting the pH of the developing waste liquid-containing raw water to a range of 5.5 to 7, adding an inorganic flocculant and then adding a polymer flocculant ; A water treatment method comprising: The water treatment method according to claim 1,
The water treatment method characterized by making the load in the said immersion membrane activated sludge process process into the range of 0.4-1.5kgBOD / m < ³ > / day. The water treatment method according to claim 1 or 2,
The water treatment method characterized by making the sludge density | concentration in the said immersion membrane activated sludge process process into the range of 3,000-10,000 mg / L. The water treatment method according to any one of claims 1 to 3,
The water treatment method characterized by further including the reverse osmosis membrane process process which performs the separation process of the biologically treated water which performed the said activated sludge process using a reverse osmosis membrane. A water treatment apparatus provided with a submerged membrane activated sludge treatment means for performing development sludge treatment using a submerged membrane with a development waste liquid-containing raw water containing a resist resin ,
A flocculation separation treatment means for adjusting the pH of the developing waste liquid-containing raw water to a range of 5.5 to 7 and adding an inorganic flocculant and then adding a polymer flocculant before the immersion membrane activated sludge treatment means. A water treatment apparatus comprising: The water treatment device according to claim 5,
A water treatment apparatus characterized in that the load in the submerged membrane activated sludge treatment means is in the range of 0.4 to 1.5 kg BOD / m ³ / day. The water treatment device according to claim 5 or 6,
A water treatment apparatus characterized in that the sludge concentration in the submerged membrane activated sludge treatment means is in the range of 3,000 to 10,000 mg / L. The water treatment apparatus according to any one of claims 5 to 7,
A water treatment apparatus further comprising reverse osmosis membrane treatment means for separating biologically treated water subjected to the activated sludge treatment using a reverse osmosis membrane.

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