JP2008023475A - Waste water treatment method and waste water treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste water treatment method for continuously and appropriately treating waste water while suppressing development of mold without requiring a large amount of expenses and preventing the failure of a waste water treatment apparatus, and to provide the waste water treatment apparatus. <P>SOLUTION: At least any one of domestic waste water and organic waste water is stored in an organic waste water tank, inorganic waste water and organic scrubber waste water are stored in an inorganic waste water tank, then pollutant in waste water in the respective waste water tanks is individually subjected to insolubilization treatment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wastewater treatment method and a wastewater treatment apparatus for several types of wastewater discharged from a semiconductor manufacturing factory.

  FIG. 5 shows a system diagram of a wastewater treatment method and a wastewater treatment apparatus in a general semiconductor manufacturing factory. The outline of the wastewater treatment apparatus is as follows: a plurality of drainage introduction paths to be described later, a drainage tank 2 for storing wastewater flowing in from this drainage introduction path, a reaction tank 3 for insolubilizing pollutants in the wastewater, A coagulation tank 4 that performs coagulation treatment, a precipitation tank 5 that performs solid-liquid separation, and a microbial treatment tank 6 that performs microbial treatment are provided. The processing content of each tank conforms to Non-Patent Document 1.

  In semiconductor manufacturing plants, there are generally four types of wastewater, namely, at least one of domestic wastewater and organic wastewater, inorganic wastewater, and organic scrubber wastewater. Here, domestic wastewater is wastewater that passes through a septic tank. Organic waste water is waste water from cleaning devices that use organic chemicals, or waste water containing phosphorus, nitrogen, ammonia, nitric acid, or the like. Inorganic wastewater is wastewater mainly composed of acid, alkali, etc. and containing boron and fluorine. Moreover, since various organic production apparatuses are used in the semiconductor manufacturing factory, exhaust gas containing organic substances is generated from these casings and pipes. This organic-containing exhaust gas is collected centrally in a scrubber and further adsorbed by activated carbon. When this activated carbon is regenerated, biochemical oxygen demand (Biochemical Oxygen Demand) of high concentration (approximately 10,000 ppm or more) , Hereinafter referred to as BOD for short)) is discharged. This is called organic scrubber drainage.

  The inorganic drainage flows into the inorganic drainage tank 21 through the inorganic drainage introduction path 11 and is stored in a shared amount. Thereafter, the wastewater is sent to the first reaction tank 31 by the pump 71, and then sent to the aggregation tank 4 and the sedimentation tank 5 in this order, and discharged as treated wastewater. The sedimentation tank 5 has a sludge treatment tank 51, and the sludge is treated here.

  On the other hand, since organic wastewater and domestic wastewater are both wastewater that requires microbial treatment, they are treated by being combined in the same drainage tank. That is, it flows into the organic drainage tank 22 through the organic drainage introduction path 12 and the domestic wastewater introduction path 13, respectively, and is temporarily stored here. Thereafter, the wastewater is sent to the second reaction tank 32 by the pump 72, and further sent to the microorganism treatment tank 6, where it is discharged as treated wastewater.

  The organic scrubber wastewater is not so high in its BOD concentration and processing efficiency that it is so recovered that it can be collected independently and subjected to dedicated processing. On the other hand, in order to perform microbial treatment on organic scrubber wastewater, the BOD concentration is high, and the treatment efficiency is also poor in this case. For this reason, a method of mixing with at least one of organic waste water and domestic waste water and treating them together is adopted. This is because the BOD concentration of organic wastewater and domestic wastewater is approximately 10 ppm to 1,000 ppm, so even if organic scrubber wastewater is mixed with this wastewater, it will be diluted to a small amount and will remain within the microbial treatment capacity. Therefore, it is based on the idea that no problem occurs. FIG. 5 shows an example of mixing in the organic drainage tank 22.

  However, in the method shown in FIG. 5, it has been found that a large amount of mold is generated in the drainage in the organic drainage tank 22. With the passage of time, not only a large amount of mold accumulates in the organic drainage tank 22, but also mold occurs in the pump 72 and the surrounding pipes that transport the wastewater, resulting in failure of the pump 72 and a decrease in the amount of drainage. It happened and proper wastewater treatment became difficult. In order to prevent the generation and accumulation of mold, the conventional methods such as blowing compressed air and injecting chemicals have been tried, but the effects are only temporary.

  As a method for preventing the occurrence of mold in such waste water, for example, in Patent Document 1, a photocatalytic functional body is installed on the inner surface of a drain groove or an inner surface of a water reservoir for flowing waste water generated in a food factory. Technology is disclosed. Patent Document 2 discloses a technique of adding a photocatalytic semiconductor to waste water and irradiating it with sunlight and / or ultraviolet rays. Further, Patent Document 3 discloses that water is fed to a fixed bed photocatalytic reactor in which titanium oxide is disposed, and water is cascade-controlled in the presence of light containing ultraviolet rays in the fixed bed photocatalytic reactor. Techniques for processing are disclosed.

In addition, it is thought that other microorganisms, for example, plankton, algae, etc. are mixed in the mold of each literature mentioned above. However, for the purpose of distinguishing from the microorganisms for treatment in the microorganism treatment tank 6, in the present invention, microorganisms that accumulate in the tank and block the pumps 71 and 72 and the piping are referred to as “mold” for convenience. I will write it down.
JP 2002-059178 A JP 2000-167573 A Japanese Patent Application Laid-Open No. 08-047687 Pollution Prevention Technology and Regulations Editorial Committee, “Fifth Amendment / Pollution Prevention Technology and Regulations [Water Quality]”, 11th edition, Japan Industrial Environment Management Association, April 10, 2005, p194-303

  However, in patent document 2, it processes in the state which disperse | distributed the ultrafine particle titanium oxide separately. For this reason, although it is necessary to isolate | separate and collect | recover a titanium oxide from a processing system, the operation involves technically very difficult. Further, Patent Document 1 and Patent Document 3 are very disadvantageous in terms of cost because it is necessary to install a large number of light sources capable of irradiating ultraviolet rays in addition to installing the photocatalytic functional body on the inner surface of the drainage tank. Moreover, when the mold generation / growth speed is fast, a sufficient effect cannot be expected. Therefore, a method for suppressing the occurrence of mold itself is desirable.

  An object of the present invention is to provide a wastewater treatment method and a wastewater treatment device capable of suppressing the occurrence of mold without enormous costs and continuously performing appropriate wastewater treatment while preventing failure of the wastewater treatment device. Is to provide.

  In order to solve the above problems, first, the conditions for mold generation were examined. The above four types of wastewater were mixed and the occurrence of mold was investigated. Table 1 shows the mixing conditions and results.

  The mixing ratio of the mixed waste water is 1: 1 for No.4, 5, 6, 8 and 1: 1 for No.7. In addition, “no occurrence” of the occurrence of mold indicates a case where “more than 15 days” does not occur.

  From this survey result, it was found that when organic scrubber wastewater was mixed with either organic wastewater or domestic wastewater, mold would occur in 1 to 2 days. On the other hand, no mold was generated in the wastewater alone, the mixed wastewater of organic wastewater and domestic wastewater, and the mixed wastewater of inorganic wastewater and organic scrubber wastewater.

Although the theoretical clarification of the cause of this survey result has not been made at present, the following two conditions coincided with each other by chance, creating a very good environment for mold growth. It is thought to be based on that.
a) By mixing organic scrubber wastewater with at least one of organic wastewater and domestic wastewater, the BOD concentration was appropriate for mold growth.
b) As a pollutant in organic wastewater and domestic wastewater, it must contain abundant sources of mold nutrients (phosphorus, nitrogen, other organic matter, etc.).

Based on the above survey results, the inventors have come up with a method for treating wastewater without mixing organic scrubber wastewater with either domestic wastewater or organic wastewater as a means for suppressing the occurrence of mold. . The features of the present invention are as follows.
(1) The wastewater treatment method according to the present invention stores at least one of domestic wastewater and organic wastewater in an organic wastewater tank, and stores inorganic wastewater and organic scrubber wastewater in an inorganic wastewater tank. The insolubilization treatment of the pollutant in the drainage of each drainage tank is performed separately.
(2) The wastewater treatment apparatus according to the present invention sends an inorganic drainage tank to which an inorganic drainage introduction path and an organic scrubber drainage introduction path are connected, and wastewater from the inorganic drainage tank, A first reaction tank that performs insolubilization treatment, an organic drainage tank to which any one of the domestic wastewater introduction path and the organic drainage introduction path is connected, and the wastewater from the organic drainage tank is sent to the pollutant in the drainage. And a second reaction tank for insolubilizing the substance.
(3) In the above (2), further comprising: a flocculation tank for treating the wastewater treated in the first reaction tank; and a microorganism treatment tank for treating the wastewater treated in the aggregation tank; The reaction tank is connected to any of the treatment tanks located between the aggregation tank and the microorganism treatment tank.
(4) In the above (2) or (3), the second reaction tank is further connected to the microorganism treatment tank.
(5) The wastewater treatment apparatus according to the present invention is an organic wastewater treatment apparatus for treating domestic wastewater, organic wastewater, and organic scrubber wastewater, wherein at least one of the domestic wastewater introduction route and the organic wastewater introduction route is connected. A microbial drainage tank, a reaction tank that sends wastewater from the organic drainage tank and insolubilizes pollutants in the drainage, and a microbial treatment tank that performs microbial treatment on the effluent of the reaction tank. An organic scrubber drainage introduction path is connected to the treatment tank.

  According to the present invention, organic scrubber wastewater is mixed with neither domestic wastewater nor organic wastewater, thereby suppressing the mold generated in the wastewater treatment device and preventing the failure in the wastewater treatment device. It is done. Further, as compared with the conventional example, it is possible to cope with the problem by changing at least one drainage introduction route, so that the above effect can be obtained at a low cost without enormous costs.

  The present invention will be described in detail based on the embodiment shown in the drawings. In addition, the same code | symbol was attached | subjected to the same thing as the prior art example of FIG.

  First, an example of the first embodiment is shown in a system diagram in FIG. In this example, the organic scrubber drainage introduction path 14 is connected to the inorganic drainage tank 21, and the organic scrubber wastewater and the inorganic wastewater are mixed and processed.

  That is, first, the inorganic wastewater flows into the inorganic wastewater tank 21 through the inorganic wastewater introduction route 11 and the organic scrubber wastewater through the organic scrubber wastewater introduction route 14, respectively. Later, it is transferred to the first reaction tank 31 by the pump 71.

  Next, slaked lime is added in the first reaction tank 31 to insolubilize dissolved contaminants (particularly boron, fluorine, etc.).

  Next, in the flocculation tank 4, a larger floc is formed by adding a polymer flocculant to the fine insolubilized pollutant flocs generated by the reaction in the first reaction tank 31. Furthermore, solid-liquid separation is performed in the next precipitation tank 5. At this time, the slurry such as floc that is solid-liquid separated in the sedimentation tank 5 passes through the sludge treatment tank 51 and is processed as a cake having a prescribed moisture content.

  On the other hand, the liquid portion obtained by solid-liquid separation in the sedimentation tank 5 is sent to the first microorganism treatment tank 61, and is processed by the microorganism treatment so that the BOD concentration is mainly within the regulated concentration range. The inflow amount of the organic scrubber wastewater into the inorganic wastewater tank 21 is adjusted so that the BOD concentration is within a range in which the microorganism can be treated in this tank. In addition, the waste water after microbial treatment is discharged as treated waste water.

  On the other hand, the organic drainage introduction path 12 and the domestic wastewater introduction path 13 are connected to an organic drainage tank 22. Therefore, first, the organic wastewater flows into the organic drainage tank 22 through the organic wastewater introduction route 12 and the domestic wastewater introduction route 13 through the organic wastewater introduction route 13, and after the water amount and the water quality are appropriately adjusted, 2 It is transferred to the reaction tank 32.

  Next, in the second reaction tank 32, polyaluminum chloride is added to dissolve and dissolve dissolved contaminants (particularly, colloidal particles such as phosphorus and silicon, organic fine particles, etc.) and insolubilized contaminants. , Oil or solids are removed and solid-liquid separation is performed.

  Next, the liquid portion obtained by solid-liquid separation in the second reaction tank 32 is sent to the second microbial treatment tank 62, and the removal of nitrogen and the BOD concentration are mainly within the regulated concentration range by the microbial treatment. The process is performed as follows. In addition, the wastewater treated with microorganisms is discharged as treated wastewater.

  As described above, according to the present embodiment, mold generated in the wastewater treatment apparatus can be suppressed, and failure of the wastewater treatment apparatus due to mold can be prevented. Moreover, it can implement | achieve only by changing the waste_water | drain introduction path | route 1 in one place, and can process cheaply without incurring huge cost.

  Next, an example of the second embodiment is shown in a system diagram in FIG. In this example, the microorganism treatment tanks 61 and 62 separated in the first embodiment are configured to be treated by one microorganism treatment tank 6.

  That is, after treating organic wastewater and domestic wastewater in the organic wastewater tank 22 and the second reaction tank 32, the liquid part obtained by solid-liquid separation in the second reaction tank 32 is sent to the microorganism treatment tank 6. Separately, microbial treatment is performed by mixing inorganic wastewater and organic scrubber wastewater with treated water. The microbially treated waste water is discharged as treated waste water.

  As described above, in the present embodiment, only one microorganism treatment tank is installed, and it is realized only by changing the drainage introduction path 1 as compared with the conventional example. Therefore, it can be processed at low cost without enormous costs. In addition, since organic wastewater with low BOD concentration and domestic wastewater are mixed and diluted, the burden on microbial treatment can be relatively reduced.

  In the present embodiment, the microbial treatment tank 6 is a tank for further mixing the mixed wastewater composed of inorganic wastewater and organic scrubber wastewater and the mixed wastewater composed of organic wastewater and domestic wastewater. Is not limited to this. In addition, you may use the coagulation tank 4 connected by the path | route A in FIG. 2, or the sedimentation tank 5 connected by the path | route B in FIG. In short, it is sufficient that the pollutants from the organic waste water and domestic waste water are removed to some extent in the organic scrubber waste water. Which one is selected can be appropriately selected depending on the layout of the apparatus and the contents of waste water.

  Moreover, in this Embodiment, although the location which further mixes the mixed waste_water | drain which consists of inorganic wastewater and organic scrubber wastewater, and the mixed wastewater which consists of organic wastewater and domestic wastewater was made into the microorganism treatment tank 6, this book The invention is not limited to this. In addition, the pipes of both mixed drains may be connected to each other and mixed in the pipe. This can also be selected as appropriate according to the layout of the apparatus and the content of waste water.

  Next, an example of the third embodiment is shown in a system diagram in FIG. In this example, the organic scrubber wastewater that has been allowed to flow into the inorganic drainage tank 21 in the first embodiment is directly flowed into the microorganism treatment tank 6 for treatment.

  That is, after treating organic wastewater and domestic wastewater in the organic wastewater tank 22 and the second reaction tank 32, the liquid part obtained by solid-liquid separation in the second reaction tank 32 is sent to the microorganism treatment tank 6. In this microorganism treatment tank 6, the organic scrubber waste water is mixed to perform the microorganism treatment. In addition, the wastewater treated with microorganisms is discharged as treated wastewater.

  This embodiment is effective when the pollutant in the organic scrubber wastewater contains less oil and solids and there is no need for solid-liquid separation in the reaction tank 3. Since pollutants are mixed in organic wastewater and domestic wastewater in a state where they are removed to some extent, generation of mold can be prevented.

  As described above, the present embodiment has the same configuration as that of the second embodiment, and can be coped with only by changing the drainage introduction route as compared with the conventional example. . For this reason, processing cost can be reduced. In addition, since organic wastewater with low BOD concentration and domestic wastewater are mixed and diluted, the burden on microbial treatment can be relatively reduced.

The pump 72 for the organic drainage tank of the wastewater treatment apparatus (example of the present invention) shown in FIG. 1 and the pump 72 for the organic drainage tank of the wastewater treatment apparatus (conventional example) shown in FIG. Time changes were compared. Immediately after the drainage tank 2 and the pump 72 are cleaned, the pump operating time is set to 0 hr, and if the pump discharge flow rate is reduced from the original 9 m ³ / hr, it is determined that mold is generated and accumulated.

FIG. 4 is a graph showing the obtained results. The vertical axis represents the discharge flow rate (m ³ / Hr) of the organic drainage tank pump 72 per hour, and the horizontal axis represents the pump operating time (Hr).

  When the organic scrubber wastewater was treated by flowing into the inorganic drainage tank 21, the pump discharge amount hardly changed. In the inorganic drainage tank 21 and the organic drainage tank 22, the occurrence of mold in the tank by visual observation was not confirmed. On the other hand, when the organic scrubber wastewater was treated in the organic wastewater tank 22 together with the organic wastewater and the domestic wastewater, the pump discharge amount was reduced to about half in 4 hours and to about 1/9 in 9 hours. When the organic drainage tank 22 was confirmed visually, a large amount of mold was generated in the tank, and the inside of the pump 72 and the surrounding piping were blocked by these molds. From the above results, the effectiveness of the present invention was confirmed.

  The present invention uses not only semiconductor manufacturing factories but also organic solvents and inorganic chemicals, and these four types of wastewater are discharged into roughly three categories: domestic wastewater, organic wastewater, inorganic wastewater, and organic scrubber wastewater. It can also be applied in factories.

1 is a system diagram of a first embodiment of a wastewater treatment method and a wastewater treatment apparatus according to the present invention. It is a systematic diagram of 2nd Embodiment of the waste water treatment method and waste water treatment apparatus which concern on this invention. It is a systematic diagram of 3rd Embodiment of the waste water treatment method and waste water treatment apparatus which concern on this invention. It is the graph which showed the time change of the discharge amount of the pump for organic drainage tanks in the example of the present invention and the conventional example. It is a systematic diagram of the waste water treatment method and waste water treatment equipment in a general semiconductor manufacturing factory (conventional example).

Explanation of symbols

11 Inorganic drainage introduction route 12 Organic wastewater introduction route 13 Domestic wastewater introduction route 14 Organic scrubber drainage introduction route 2 Drainage tank 21 Inorganic drainage tank 22 Organic drainage tank 3 Reaction tank 31 First reaction tank (inorganic reaction tank)
32 Second reaction tank (organic reaction tank)
4 Coagulation tank 5 Sedimentation tank 51 Sludge treatment tank 6 Microbial treatment tank 61 First microorganism treatment tank 61 Second microorganism treatment tank 71 Pump (for inorganic drainage tank)
72 Pump (for organic drainage tank)

Claims (5)

  After storing at least one of domestic wastewater and organic wastewater in an organic wastewater tank, storing inorganic wastewater and organic scrubber wastewater in an inorganic wastewater tank, then insolubilizing pollutants in the drainage of each drainage tank A wastewater treatment method, wherein the treatment is performed separately.   An inorganic drainage tank to which an inorganic drainage introduction path and an organic scrubber drainage introduction path are connected, a first reaction tank that sends wastewater from the inorganic drainage tank and insolubilizes pollutants in the drainage, and life An organic drainage tank to which any one of the drainage introduction path and the organic drainage introduction path is connected; a second reaction tank for sending wastewater from the organic drainage tank and insolubilizing the pollutants in the drainage; A wastewater treatment apparatus comprising:   A coagulation tank for treating the wastewater treated in the first reaction tank; and a microbial treatment tank for treating the wastewater treated in the coagulation tank; and The waste water treatment apparatus according to claim 2, wherein the waste water treatment apparatus is connected to any one of the treatment tanks between the microorganism treatment tanks.   The waste water treatment apparatus according to claim 2 or 3, wherein the second reaction tank is connected to the microorganism treatment tank. In wastewater treatment equipment for treating domestic wastewater, organic wastewater, and organic scrubber wastewater,
An organic drainage tank to which at least one of a domestic wastewater introduction path and an organic drainage introduction path is connected; a reaction tank that sends wastewater from the organic drainage tank and insolubilizes pollutants in the drainage; and the reaction A wastewater treatment apparatus comprising: a microorganism treatment tank that performs a microorganism treatment on the wastewater of the tank; and an organic scrubber drainage introduction path connected to the microorganism treatment tank.

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