JP3818706B2 - Biological treatment method and apparatus for waste water - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biological treatment method and apparatus for wastewater, and more particularly to a method and apparatus for biologically treating wastewater such as factory wastewater discharged from a manufacturing process.
[0002]
[Prior art]
In recent years, industrial wastewater discharged from manufacturing processes at business establishments, for example, organic wastewater and wastewater containing various chemical substances such as fluorine, are discharged into sewers or directly into public water bodies (rivers, etc.) Before, it is very important to process for removing harmful substances, pollutants and the like. For example, the national and local governments have established laws such as the Water Pollution Control Act and regulations on the emission standards of various chemical substances to prevent environmental pollution and water pollution caused by wastewater. When setting up wastewater, business establishments, etc., must treat the wastewater in a complete form so that the concentration of harmful substances in the wastewater is below the standard value.
[0003]
As one method of wastewater treatment, biological wastewater treatment that biologically treats wastewater is widely used, and has achieved good results. Biological treatment is a treatment method aimed at stabilizing organic matter in the wastewater and changing it to a solid content that tends to settle by utilizing the metabolic action of the organisms contained in the wastewater. The biological treatment process can be roughly classified into a biological suspension method in which an organism is suspended and treated, such as an activated sludge method, and a biological fixation method in which treatment is performed by fixing the organism to a carrier or the like.
[0004]
Conventional typical biological wastewater treatment is, for example, anaerobic treatment in which wastewater is treated in the absence of oxygen, and organic substances are decomposed by the action of organisms contained in the wastewater. However, this method has a problem that it is difficult to maintain and manage the concentration of organisms because it is necessary to use a biological suspension treatment tank for its implementation in order to keep the inside of the treatment tank in an anaerobic state. . That is, in the case of this method, it is necessary to keep the biological concentration in the treatment tank high and constant in order to stabilize the treatment, and this work takes a lot of man-hours and time.
[0005]
Moreover, in the conventional treatment of biological wastewater containing fluorine, an operation of pre-aggregating and precipitating with, for example, slaked lime (calcium hydroxide) is performed prior to biological treatment. In order to avoid various alkaline earth metal salts remaining in this work and originally contained in the wastewater from adversely affecting biological treatment, additional coagulation and precipitation treatment using sodium carbonate or the like is usually used. Are used together. Moreover, the installation space of a processing apparatus must be taken wide for this additional coagulation sedimentation processing.
[0006]
[Problems to be solved by the invention]
The object of the present invention is to solve the problems of the conventional technology as described above, and does not require complicated wastewater treatment operation, and biological wastewater that enables stable treatment of wastewater that requires biological treatment. It is to provide a processing method.
Another object of the present invention is to provide such a biological wastewater treatment apparatus for carrying out such a biological wastewater treatment method and does not require a large installation space.
[0007]
Other objects of the present invention will be readily understood from the following detailed description.
[0008]
[Means for Solving the Problems]
In one aspect of the present invention, when wastewater is biologically treated, the biological treatment in the anaerobic biological fixed bed and the subsequent backwashing treatment using an inert gas are performed in combination. Biological wastewater treatment method.
In another aspect, the present invention is a device for biologically treating waste water, and comprises a combined biological fixed bed device with pure oxygen aeration after the alkaline earth coagulation sedimentation. It is in the biological wastewater treatment equipment characterized by.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The biological wastewater treatment method and apparatus according to the present invention can have various preferred embodiments. Although not limited to the following, preferred embodiments of the present invention are described below.
As described above, the biological wastewater treatment method of the present invention is characterized in that the biological treatment in the biological fixed bed and the subsequent backwash treatment using an inert gas are performed in combination. Here, the biological fixed bed as an anaerobic tank can have a structure usually used in this technical field, and therefore, the filler for biological fixation is also a material well known in this technical field. Can be. Examples of suitable fillers include porous ores and fiber materials. With this filler, the biological concentration in the fixed bed can be kept constant at a high concentration throughout the biological treatment. In addition, the size of the fixed bed and the shape and size of the filler packed therein can be widely changed depending on factors such as the scale of the wastewater treatment and the desired result.
[0010]
The organisms to be fixed on the organism fixed bed may be changed depending on the composition of the drainage, but as examples of suitable organisms, microorganisms such as zoglea, amoeba, and worm beetle. Such organisms naturally settle and multiply.
In the method of the present invention, after performing biological treatment for a certain period of time, or after performing biological treatment by supplying a predetermined amount of waste water to the biological fixed bed, backwashing treatment is performed using an inert gas. The backwashing treatment is for removing surplus organisms in the fixed bed, and can be performed by blowing an inert gas instead of air into the fixed bed, as is generally done in this technical field. it can. Examples of suitable inert gas include nitrogen gas and argon gas, which are cheaper than pure enzymes, and examples of means for injecting this gas include a diffuser tube, a spray nozzle, and a perforated conduit. It is done. The backwash process with an inert gas is preferably performed automatically with time. Further, in combination with this inert gas backwashing treatment, if necessary, water backwashing using water may be used in combination.
[0011]
The biological wastewater treatment method of the present invention can be implemented as an aerobic biological treatment instead of the above-described anaerobic biological treatment. In this case, when performing biological treatment on the biological fixed bed, pure oxygen is aerated on the fixed bed. If possible, an oxygen-enriched gas may be used instead of pure oxygen. The aeration method may be performed in accordance with the above-described back washing treatment, or may be performed according to other known methods. This pure oxygen aeration makes it possible to perform a high-load treatment, and therefore, it is possible to omit the coagulation-precipitation treatment conventionally performed. That is, according to the present invention, the wastewater can be directly fed into the biological fixed bed as it is. After performing the predetermined treatment on the biological fixed bed, the waste water is backwashed. Although this backwashing treatment can be performed using a pure enzyme, as described above, backwashing using an inert gas such as nitrogen gas is advantageous in terms of cost.
[0012]
In addition, when wastewater that requires biological treatment contains harmful substances such as fluorine, the alkaline earth metal salts in the wastewater are coagulated and precipitated with, for example, slaked lime, and the state is kept as it is. The treatment can be carried out on a biological fixed bed. It is not necessary to install a special means for collecting the aggregated sediment in front of the biological fixed bed. Here, if an aerobic treatment is performed, pure oxygen is supplied to the fixed bed, and if an anaerobic treatment is performed, an inert gas such as nitrogen gas is supplied to the fixed bed. After performing the predetermined treatment on the biological fixed bed, the wastewater is backwashed as necessary. This backwashing treatment is advantageously performed using an inert gas such as nitrogen gas as described above.
[0013]
The biological wastewater treatment apparatus of the present invention is characterized by comprising a biological fixed bed apparatus and a subsequent inert gas backwashing treatment apparatus in combination. Here, the biological fixed bed apparatus can be an ordinary apparatus including the biological fixed bed as described above, and includes an air diffuser for backwashing, aeration, or the like, and an automatic valve for venting air. Can be equipped. Furthermore, an inert gas backwashing device is preferably connected to this device via a conduit. The backwashing apparatus can be configured with a buffer tank, as is common in this technical field.
[0014]
The biological fixed bed apparatus can preferably be equipped with a pure oxygen aeration apparatus. The pure oxygen aeration apparatus can be configured with a buffer tank, similarly to the backwash processing apparatus described above, or may have other conventional configurations.
In addition, the biological wastewater treatment apparatus can preferably have an alkaline earth salt coagulation sedimentation treatment apparatus upstream of the biological fixed bed apparatus and the subsequent inert gas backwashing treatment apparatus. As the alkaline earth salt agglomeration sedimentation treatment apparatus, an apparatus generally used in this technical field can be used as it is or after modification. It is not necessary to install an extra device such as a sediment collection device between the alkaline earth salt coagulation sedimentation treatment device and the biological fixed bed device.
[0015]
In the biological wastewater treatment apparatus according to the present invention, the individual devices constituting the same are connected to each other in the normal manner in this technical field, and need not be described here. Automatic valves, measuring instruments, and other means can be attached.
[0016]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the present invention is not limited to these examples.
FIG. 1 is a system diagram of an anaerobic biological wastewater treatment apparatus using an inert gas for backwashing. The wastewater from the FRP drainage raw water tank 1 is supplied to the biological treatment tank 4 through a water pipe 11. Here, the biological treatment tank 4 is an anaerobic fixed bed made of mild steel and having a hard rubber lining. As shown in the drawing, the fixed tank 41, the diffuser pipe 42, and an automatic valve 43 for venting air are provided. Equipped. The filler of the fixed bed 41 is a porous ore, and the organisms fixed to it are Bacillus, methanogen, and the like. Since the biological treatment tank 4 is a fixed bed, the biological concentration is kept at a high concentration, and therefore biological treatment can be performed stably. After the biological treatment is performed for a certain period of time or after the treatment of the waste water at a predetermined flow rate is completed, the automatic valve 15 is opened, and the inert gas (here, nitrogen gas) in the buffer tank 5 is transferred to the biological treatment tank 4. Introduce. Since the inert gas is injected from the diffuser tube 42, the fixed bed 41 can be backwashed from below. During the backwashing with the inert gas, the automatic valve 43 is also opened to release air. If necessary, the water in the treatment water tank 6 may be introduced through the automatic valve 16 by the backwash pump 17, and additional water backwash may be performed in the lower part of the biological treatment tank 4. For backwashing with water, it is usually preferable to feed 2 to 3 times the amount of treated water. After completion of the backwash treatment, the treated water generated in the biological treatment tank 4 is sent to the treated water tank 6 via the automatic valve 19, and the backwash drainage is sent to the backwash drainage tank 7 via the automatic valve 18. Sent.
[0017]
As a modification of the above-described anaerobic biological wastewater treatment apparatus, aerobic biological wastewater treatment can be performed using the same apparatus and basically according to the same technique. In this case, pure oxygen is used in the buffer tank 5 in place of the inert gas, and the pure oxygen is aerated by opening the automatic valve 15 and introducing it into the biological treatment tank 4 from the diffuser tube 42. The aeration conditions are adjusted so that the dissolved oxygen amount in the tank is 1 to 1.2 ppm. By this treatment, a high load treatment is possible, and a biological treatment after the alkaline earth salt coagulation sedimentation treatment is also possible. After biological treatment is complete, backwash the wastewater. Here, although the automatic valve 15 can be opened and pure oxygen in the buffer tank 5 can be introduced into the biological treatment tank 4, it is preferable to use an inert gas such as nitrogen gas in order to reduce costs. That is, it is preferable to switch the opened automatic valve 15 to the automatic valve 14 and introduce an inert gas (in this case, using nitrogen gas) in another chamber of the buffer tank 5 into the biological treatment tank 4.
[0018]
FIG. 2 is a system diagram of a biological wastewater treatment apparatus capable of continuously performing a coagulation sedimentation treatment of an alkaline earth metal salt and a subsequent biological treatment. This biological wastewater treatment apparatus can be advantageously used for the treatment of vital biological wastewater containing fluorine or the like.
The wastewater from the raw water tank 1 made of PE is supplied to a reaction tank 2 made of mild steel and having a hard rubber lining, and further to a precipitation tank 3 made of mild steel and having a tar epoxy lining. The In the sedimentation tank 3, the coagulation sedimentation treatment of the alkaline earth metal salt is performed using slaked lime according to a conventional technique. The precipitate generated as a result of this coagulation sedimentation process is discharged as sludge through the mud pump 13. The waste water after the precipitation treatment is directly and continuously supplied to the biological treatment tank 4 via the liquid feed pump 12. The treatment in the biological treatment tank 4 can be basically performed according to the method described with reference to FIG. In this example as well, if aerobic biological treatment is performed, pure oxygen is accommodated in the buffer tank 5 and introduced into the biological treatment tank 4 by opening the automatic valve 14, and anaerobic biological treatment is performed. If there is, an inert gas is accommodated in the buffer tank 5 and introduced into the biological treatment tank 4 by opening the automatic valve 14.
[0019]
Further, although FIG. 2 particularly describes fixed-bed biological treatment, floating biological treatment can be used instead if desired.
[0020]
【The invention's effect】
As described above, according to the present invention, since backwashing is performed using an inert gas in a biological fixed bed, high-load treatment can be performed, and highly stable anaerobic biological treatment can be performed. In that case, it is unnecessary to perform complicated wastewater treatment. In addition, when aerobic biological treatment is performed instead of the anaerobic biological treatment as described above, pure oxygen aeration is performed on the biological fixed bed, and thus high load treatment can be performed, and alkaline earth salt removal can be performed. The waste water after the alkaline earth salt coagulation sedimentation treatment can be directly and continuously treated on the biological fixed bed without providing a special coagulation sedimentation tank. In addition, since a coagulation sedimentation tank is not required, the installation space for the apparatus can be reduced. Therefore, the biological wastewater treatment method and apparatus according to the present invention can reduce the processing cost and the processing space or prevent water pollution in establishments where organic wastewater, wastewater containing biological treatment containing fluorine, etc. are forced to be discharged. There is a significant contribution to environmental conservation.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a preferred embodiment of a biological wastewater treatment apparatus according to the present invention.
FIG. 2 is a system diagram showing another preferred embodiment of the biological wastewater treatment apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Waste water source tank 2 ... Reaction tank 3 ... Precipitation tank 4 ... Biological treatment tank 5 ... Buffer tank 6 ... Treatment water tank 7 ... Backwash drain tank 11 ... Water feed pump 12 ... Liquid feed pump 13 ... Mud pump 14 ... Automatic valve DESCRIPTION OF SYMBOLS 15 ... Automatic valve 16 ... Automatic valve 17 ... Backwash pump 18 ... Automatic valve 19 ... Automatic valve 41 ... Fixed bed 42 ... Aeration pipe 43 ... Automatic valve

Claims (3)

In treating biologically the wastewater containing fluorine discharged from the manufacturing process,
Supplying the waste water to a coagulation sedimentation tank to precipitate alkaline earth metal salts by coagulation sedimentation treatment,
The wastewater after the precipitation treatment is directly supplied to a biological treatment tank equipped with an anaerobic biological fixed bed and inert gas blowing means,
In the biological treatment tank, the biological treatment using the inert gas in the anaerobic biological fixed bed is performed, and the biological treatment is performed after the biological treatment is performed for a predetermined time or by supplying a predetermined amount of wastewater to the biological fixed bed. A biological wastewater treatment method, comprising: performing a backwashing treatment of the biological fixed bed using an inert gas after performing, and removing surplus organisms in the fixed bed in the backwashing treatment. In treating biologically the wastewater containing fluorine discharged from the manufacturing process,
Supplying the waste water to a coagulation sedimentation tank to precipitate alkaline earth metal salts by coagulation sedimentation treatment,
The wastewater after the precipitation treatment is directly supplied to a biological treatment tank equipped with an aerobic biological fixed bed, pure oxygen blowing means and inert gas blowing means,
In the biological treatment tank, the biological treatment using pure oxygen in the aerobic biological fixed bed is performed, and the biological treatment is performed for a predetermined time or by supplying a predetermined amount of waste water to the biological fixed bed. Then, the biological wastewater treatment method is characterized in that the biological fixed bed using an inert gas is backwashed, and the surplus organisms in the fixed bed are removed in the backwashing treatment. The wastewater containing fluorine discharged from the manufacturing process a biologically processing apparatus,
Coagulation sedimentation tank for precipitating alkaline earth metal salts from the waste water, and anaerobic organism fixed bed to which the waste water from the coagulation sedimentation tank is directly supplied as it is and anaerobic means equipped with inert gas blowing means The biological fixed bed using an inert gas after having been subjected to biological treatment for a certain period of time or after biological treatment by supplying a predetermined amount of wastewater to the biological fixed bed. The biological wastewater treatment apparatus is characterized in that the backwash process is performed, and surplus organisms in the fixed bed are removed in the backwash process.

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