JP2012035232A - Wastewater treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wastewater treatment system capable of stably treating wastewater with high efficiency while preventing the enlargement of an active sludge treating apparatus and an increase in running cost.SOLUTION: The wastewater treatment system 1C includes a wastewater treating apparatus 100, the active sludge treating apparatus 200. and a combustion apparatus 300. The wastewater treating apparatus 100 includes adsorption elements 111, 121 adsorbing and desorbing organic compounds in wastewater, and continuously treats wastewater to discharge primary treated water and desorption gas. The active sludge treating apparatus 200 has active sludge containing microorganisms that decompose the organic compounds, and discharges the primary treated water as secondary treatment water.

Description

  The present invention relates to a wastewater treatment system that purifies the wastewater by removing the organic compound from the wastewater containing the organic compound. In particular, the present invention relates to a wastewater treatment system for purifying industrial wastewater by efficiently removing organic compounds from industrial wastewater containing organic compounds discharged from various factories and research facilities.

  Conventionally, an activated sludge treatment apparatus has been used as a wastewater treatment apparatus for purifying wastewater containing organic compounds. The activated sludge treatment apparatus is an apparatus for purifying waste water using activated sludge mainly containing aerobic microorganisms such as bacteria (bacteria), protozoa, and metazoans, and details thereof are disclosed in, for example, Patent Document 1 and the like. Has been.

  The activated sludge treatment apparatus supplies wastewater to the above-described activated sludge, and agitates and aerates it to decompose and remove organic compounds contained in the wastewater using microorganisms, thereby separating activated sludge. It is a device that cleans and discharges clean water.

  In the activated sludge treatment apparatus described above, since microorganisms are used for decomposing organic compounds, it is very difficult to continuously and stably maintain conditions suitable for the microorganisms to decompose organic compounds. Therefore, when it was set as the wastewater treatment system provided with the activated sludge processing apparatus, there existed a problem that it became difficult to maintain the wastewater processing capacity stably.

  Therefore, the water discharged from the activated sludge treatment device is generally treated using an exchangeable wastewater treatment device using cartridge-type activated carbon as an adsorbent. Organic compounds contained in the water are removed by the cartridge-type activated carbon and discharged from the exchangeable waste water treatment device as clean water.

  However, in the exchangeable wastewater treatment device, if the adsorption capacity of the adsorbent reaches saturation by continuing to adsorb the organic compound for a certain period of time, the adsorption is not substantially performed thereafter, and replacement work with a new one, or once An operation of removing the adsorbent from the apparatus and performing a regeneration process is required. Therefore, when it is set as the waste water treatment system which processes the water discharged from the activated sludge treatment device using the exchangeable waste water treatment device, the water cannot be continuously treated. It was necessary to stop each time.

  In addition, unlike the purification of air, the purification of water inevitably causes the growth of microorganisms, and the life of the adsorbent is shortened. Therefore, in the case of a wastewater treatment system that treats water discharged from the activated sludge treatment device using an exchangeable wastewater treatment device, it is necessary to frequently perform the above-described adsorbent replacement work and regeneration treatment work. There was also a problem that the labor and running cost increased.

  In addition, when a large amount of wastewater containing organic compounds at high concentration is treated with activated sludge treatment equipment, the amount of activated sludge required will increase accordingly. The increase of becomes inevitable. In addition, in activated sludge treatment equipment, it is necessary to constantly adjust and optimize the amount of activated sludge according to the amount of organic compounds contained in the wastewater to be treated. It is necessary to always collect and discharge from the apparatus, and there is a problem that it takes time and money to dispose of this excess sludge. Therefore, when the amount of activated sludge is increased as described above, there is a problem that the amount of surplus sludge to be discarded also increases, and the running cost increases significantly.

  In order to solve such a problem, an adsorption / desorption type water treatment apparatus and a water treatment system that can be removed efficiently and stably by alternately performing an adsorption step and a desorption step have been studied (for example, Patent Document 2). And 3). This water treatment system realizes continuous purification of water and basically eliminates the need to replace the adsorbent, and can remove a large amount of organic substances with high efficiency and stability.

  However, the water treatment systems described in Patent Documents 2 and 3 also have technical problems. For example, in Patent Document 3, surplus sludge generated from the activated sludge apparatus is separated in a sedimentation tank, but if the excess sludge flows out without being separated even in a very small amount, it is connected to the subsequent stage of the activated sludge apparatus. Since the excess sludge accumulates in the adsorbent of the adsorption / desorption type water treatment equipment and the excess sludge does not desorb from the adsorbent with the heated gas, the adsorbent adsorption capacity may decrease in a short period of time. In such a situation, it is necessary to stop the waste water treatment system each time and replace the adsorbent as in the case of the exchangeable adsorption device, which takes time and increases costs.

  In addition, when the concentration of organic compounds in the wastewater is high, it is diluted tens to hundreds of times with industrial water before introducing the wastewater into the activated sludge device in order to reduce the load on the activated sludge. There is a case. For example, when treating wastewater containing organic compounds that are hardly decomposable for microorganisms such as 1,4-dioxane or organic compounds that are highly toxic to microorganisms, there is a case of further diluting. In such a case, not only does the amount of wastewater after activated sludge treatment increase, but the adsorption linear velocity increases due to the increase in the amount of wastewater, so even if the amount of organic compounds is the same as that without dilution, the adsorption capacity In some cases, there is a problem that the adsorption / desorption type water treatment apparatus connected in the latter stage is increased in size and cost.

JP-A-9-10791 JP 2006-55712 A JP 2010-142792 A

  The present invention has been made to solve the above-mentioned problems, and the activated sludge treatment apparatus can prevent the increase in size and the running cost, and the organic compound has low biodegradability without stopping the system. It is an object of the present invention to provide a wastewater treatment system capable of continuously purifying wastewater including wastewater and capable of treating wastewater with high efficiency and stability.

  The waste water treatment system based on this invention cleans the said waste water by removing an organic compound from the waste water containing an organic compound, Comprising: The waste water treatment apparatus and the activated sludge treatment apparatus are provided.

The waste water treatment apparatus has an adsorbing element containing an adsorbent that adsorbs an organic compound by contacting waste water containing an organic compound and desorbs the organic compound adsorbed by contacting gas, and By supplying wastewater containing an organic compound to the element, the organic compound is adsorbed by the adsorbing element, and water that has passed through the adsorbing element is discharged as primary treated water. Thereafter, by supplying a heating gas to the adsorption element, the organic compound adsorbed on the adsorption element is desorbed and discharged as a desorption gas containing the organic compound.
Here, the waste water treatment apparatus shifts a portion where the desorption process of the adsorption element is completed to a portion where the adsorption process is performed, and shifts a portion where the adsorption process of the adsorption element is completed to a portion where the adsorption process is performed. Therefore, the waste water can be treated continuously.

  The activated sludge treatment apparatus has an activated sludge that is connected to the wastewater treatment apparatus and contains microorganisms that decompose the organic compounds in the primary treated water discharged from the wastewater treatment apparatus, and the activated sludge contains primary treated water. The organic compound is decomposed and removed by microorganisms by contacting with water and discharged as secondary treated water.

  In the wastewater treatment apparatus of the present invention, it is preferable that the wastewater treatment apparatus blows off excess wastewater adhering to the adsorption element by blowing gas to the adsorption element and discharges it as removed wastewater. . In that case, it is also preferable that the removed waste water discharged from the waste water treatment apparatus is again supplied to the waste water treatment apparatus as waste water.

  In the waste water treatment apparatus of the present invention, it is preferable that the adsorbing element contains at least one of activated carbon, activated carbon fiber, and zeolite.

  In the wastewater treatment apparatus of the present invention, it is preferable that a combustion apparatus is connected, and the desorption gas discharged from the wastewater treatment apparatus is burned to be oxidatively decomposed.

  According to the present invention, it is possible to prevent the activated sludge treatment apparatus from being increased in size and to prevent an increase in running cost, and it is possible to continuously purify the drainage water without stopping the system. It can be set as the waste water treatment system which can process the waste water contained in a density | concentration highly efficiently and stably.

1 is a system configuration diagram of a wastewater treatment system according to Embodiment 1 of the present invention. It is a schematic diagram which shows the example of the other waste water treatment equipment which can be utilized in the waste water treatment system in Embodiment 1 of this invention. It is a schematic diagram which shows the example of the other waste water treatment equipment which can be utilized in the waste water treatment system in Embodiment 1 of this invention. It is a system block diagram of the waste water treatment system in Embodiment 2 of this invention. It is a system block diagram of the waste water treatment system in Embodiment 3 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals in the drawings, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a system configuration diagram of a wastewater treatment system according to Embodiment 1 of the present invention. Below, with reference to this FIG. 1, the structure of the waste water treatment system 1A in this Embodiment is demonstrated.

  As shown in FIG. 1, the wastewater treatment system 1 </ b> A according to the present embodiment mainly includes a wastewater treatment device 100 and an activated sludge treatment device 200.

The wastewater treatment apparatus 100 includes a first treatment tank 110 and a second treatment tank 120 in which adsorption elements 111 and 121 are accommodated, respectively. The adsorbing elements 111 and 121 adsorb the organic compound contained in the waste water by contacting the waste water containing the organic compound. That is, in the wastewater treatment apparatus 100, by supplying the wastewater to the adsorption elements 111 and 121, the organic compound contained in the wastewater is adsorbed by the adsorption elements 111 and 121, thereby cleaning the wastewater. And discharged as primary treated water.
Further, the adsorption elements 111 and 121 desorb the organic compound adsorbed by contacting the heated gas. Therefore, in the waste water treatment apparatus 100, by supplying a heating gas to the adsorption elements 111 and 121, the organic compound is desorbed from the adsorption elements 111 and 121, whereby the heating gas is discharged as a desorption gas containing the organic compound. Will be.

  Piping lines L1, L2, L3, and L4 are connected to the first processing tank 110 and the second processing tank 120, respectively. The piping line L1 is a piping line for supplying wastewater containing organic compounds to the first processing tank 110 and the second processing tank 120, and is connected to the first processing tank 110 and the second processing tank 120 by valves V101 and V102. The connection / disconnection state is switched. The piping line L2 is a piping line for supplying heated gas to the first processing tank 110 and the second processing tank 120, and is connected / disconnected to the first processing tank 110 and the second processing tank 120 by valves V103 and V104. The state is switched. The piping line L3 is a piping for discharging the primary treated water from the first treatment tank 110 and the second treatment tank 120, and is connected / disconnected to the first treatment tank 110 and the second treatment tank 120 by valves V105 and V106. The state is switched. The piping line L4 is a piping line for discharging the desorption gas from the first processing tank 110 and the second processing tank 120, and is connected / disconnected to the first processing tank 110 and the second processing tank 120 by valves V107 and V108. The state is switched.

  The 1st processing tank 110 and the 2nd processing tank 120 function as an adsorption tank and a desorption tank alternately by operating opening and closing of valve V101-V108 mentioned above. Specifically, when the first processing tank 110 functions as an adsorption tank, the second processing tank 120 functions as a desorption tank, and when the first processing tank 110 functions as a desorption tank. The second treatment tank 120 functions as an adsorption tank. That is, the waste water treatment apparatus 100 according to the present embodiment is configured such that the adsorption tank and the desorption tank are alternately switched over time. In addition, the piping line L1 is connected to the tank functioning as an adsorption tank among the first treatment tank 110 and the second treatment tank 120, and supplies drainage containing an organic compound to the adsorption tank. Is connected to a tank functioning as a desorption tank among the first treatment tank 110 and the second treatment tank 120 and supplies heated gas to the desorption tank. Moreover, the piping line L3 is connected to the tank functioning as the adsorption tank among the first treatment tank 110 and the second treatment tank 120, and discharges the primary treated water from the adsorption tank. Of the 1 treatment tank 110 and the 2nd treatment tank 120, it connects to the tank which is functioning as a desorption tank, and discharge | releases desorption gas.

  The primary treated water discharged from the waste water treatment apparatus 100 is reduced in the content of organic compounds in the water, and in particular, organic compounds that are difficult to decompose for microorganisms are greatly removed, and the next activated sludge treatment apparatus is used. The processing load is reduced.

  The adsorbing elements 111 and 121 preferably contain at least one of activated carbon, activated carbon fiber, or zeolite as an adsorbing material. The adsorbing elements 111 and 121 use activated carbon or zeolite in the form of particles, granules or honeycombs as the adsorbent, and more preferably activated carbon fibers. Since the activated carbon fiber has a fibrous structure having micropores on the surface, the contact efficiency with water is high, and the adsorption rate of organic compounds in water is particularly high, which is extremely high compared to other adsorbents. Adsorption efficiency can be realized.

The physical properties of the activated carbon fiber usable for the adsorption elements 111 and 121 are not particularly limited, but the BET specific surface area is 700 to 2000 m ² / g, and the pore volume is 0.4 to 0.9 cm ³ / g. The average pore diameter is preferably 17 to 18 mm. This is because when the BET specific surface area is less than 700 m ² / g, the pore volume is less than 0.4 m ³ / g, and the average pore diameter is less than 17 mm, the adsorption amount of the organic compound is lowered, and the BET ratio When the surface area exceeds 2000 m ² / g, the pore volume exceeds 0.9 m ³ / g, and the average pore diameter exceeds 18 mm, the adsorption capacity for substances with small molecular weight decreases due to the large pore diameter. This is because the strength becomes weak, the cost of the material becomes high, and it becomes economically disadvantageous.

  The activated sludge treatment apparatus 200 mainly has an aeration tank 210 and a sedimentation tank 220. The aeration tank 210 includes an aeration apparatus 211 and a stirrer (not shown), and the inside of the aeration tank 210 is filled with activated sludge containing aerobic microorganisms such as bacteria, protozoa, and metazoans. Has been. The aeration tank 210 supplies the primary sludge discharged from the waste water treatment device to the activated sludge so that the activated sludge and the primary treated water are brought into contact with each other, and this is stirred and aerated to be contained in the primary treated water. It is a processing tank for decomposing and removing the organic compound.

  On the other hand, the sedimentation tank 220 is a treatment tank for separating the water containing activated sludge treated in the aeration tank 210 into activated sludge and secondary treated water by solid-liquid separation.

  Piping lines L3, L5, L6, L7, L8, and L9 are connected to the activated sludge treatment apparatus 200. The piping line L3 is a piping line for supplying primary treated water to the aeration tank 210, and the piping line L5 is a piping line for supplying oxygen to the aeration device 211. The piping line L <b> 6 is a piping line for discharging water containing activated sludge from the aeration tank 210 and supplying it to the sedimentation tank 220. The piping line L7 is a piping line for discharging the surplus of the activated sludge discharged from the sedimentation tank 220 as surplus sludge, and the piping line L8 is necessary among the activated sludge discharged from the sedimentation tank 220. It is a piping line for returning a part to the aeration tank 210 as return sludge. The piping line L9 is a piping line for discharging the secondary treated water from the sedimentation tank 220.

  In the activated sludge treatment apparatus 200, the primary treated water supplied to the aeration tank 210 via the piping line L3 is mixed with the activated sludge in the aeration tank 210, and the mixed waste water and the activated sludge pass through the piping line L5. The organic compound is decomposed by being agitated while being aerated by oxygen supplied to the aeration apparatus 211 and discharged from the aeration apparatus 211. The water containing activated sludge after decomposition is sent to the sedimentation tank 220 via the piping line L6, and is separated into solid and liquid in the sedimentation tank 220, and the supernatant liquid is discharged as secondary treated water via the piping line L9. . The secondary treated water discharged from the activated sludge treatment apparatus 200 has a significantly reduced organic compound content compared to the primary treated water supplied to the activated sludge treatment apparatus 200 and can be discharged into rivers and sewage. It has been cleaned to the level.

  Next, with reference to FIG. 1, the detail of the waste water purification process performed in the waste water treatment system 1A in the present embodiment will be described. The following description is based on the state where the first treatment tank 110 of the waste water treatment apparatus 100 functions as an adsorption tank and the second treatment tank 120 functions as a desorption tank. The same process is performed when the desorption tank is replaced.

  As shown in FIG. 1, the waste water containing an organic compound is introduced into the waste water treatment apparatus 100 via a piping line L1. The introduced waste water is sent to the first treatment tank 110 and comes into contact with the adsorption element 111, and the organic compound contained in the waste water is adsorbed by the adsorption element 111. The water after the organic compound is adsorbed by the adsorbing element 111 is introduced into the piping line L3 and discharged from the waste water treatment apparatus 100 as primary treated water.

  On the other hand, the heated gas is introduced into the waste water treatment apparatus 100 via the piping line L2 in parallel with the introduction of the waste water. The introduced heated gas is sent to the second treatment tank 120 and comes into contact with the adsorption element 121 to desorb the organic compound adsorbed on the adsorption element 121. The heated gas containing the organic compound desorbed from the adsorption element 121 is introduced into the piping line L4 and discharged from the waste water treatment apparatus 100 as a desorbed gas.

  The primary treated water discharged from the waste water treatment apparatus 100 is introduced into the activated sludge treatment apparatus 200 via the piping line L3. The introduced primary treated water is brought into contact with activated sludge to decompose and remove the organic compound contained in the primary treated water, and the water after the organic compound is removed is introduced into the piping line L9. It is discharged from the activated sludge treatment apparatus 200 as secondary treated water. The discharged secondary treated water is then treated as river discharge or normal sewage.

  By using the wastewater treatment system 1A as described above, the wastewater treatment device 100 functions as a pretreatment device of the activated sludge treatment device 200, compared to the case where the wastewater treatment system is constructed only by the activated sludge treatment device, Not only is the amount of organic compounds in the wastewater treated by the activated sludge treatment apparatus 200 reduced, but organic compounds that are particularly difficult to biodegrade with activated sludge or highly toxic to microorganisms are treated in the wastewater treatment apparatus 100. Since it is removed, it is possible to make the activated sludge treatment apparatus 200 small. Furthermore, since it is also possible to treat wastewater containing organic compounds that are difficult to biodegrade, it is possible to stabilize the treatment capacity of the cleaning treatment as the whole wastewater treatment system 1A. Therefore, the activated sludge treatment apparatus 200 can be prevented from increasing in size and running cost can be prevented, and a wastewater treatment system capable of treating wastewater with high efficiency and stability can be obtained.

  Moreover, since it becomes possible to process the waste_water | drain discharged | emitted from the waste water treatment apparatus 100 continuously in the activated sludge treatment apparatus 200 by setting it as the waste water treatment system 1A as mentioned above, it is continuous without stopping a system. In addition, it becomes possible to purify the exhaust gas. Therefore, it is not necessary to replace the cartridge-type adsorbent with a new one or to remove and regenerate it, compared to the case where an exchangeable wastewater treatment device equipped with a cartridge-type adsorbent is used as a backup device for the activated sludge treatment device. Therefore, the labor and running costs are not increased.

  Moreover, by using the wastewater treatment system 1A as described above, the adsorption treatment and the desorption treatment are alternately and continuously repeated in the first treatment tank 110 and the second treatment tank 120 of the wastewater treatment apparatus 100. Thus, by comprising so that adsorption | suction processing and desorption processing may be repeated alternately and continuously, the organic compound contained in waste_water | drain can be removed stably with high capability at low cost. Therefore, by adopting the above configuration, it is possible to provide a wastewater treatment system capable of cleaning wastewater with high efficiency and stability. In particular, by using the wastewater treatment apparatus 100 as described above, it is possible to suppress the growth of microorganisms, and thus it is possible to prevent the generation of algae and the like.

  Furthermore, since the wastewater treatment system 1A as in the present embodiment can be easily realized by simply adding the wastewater treatment device 100 to the existing wastewater treatment system having only the activated sludge treatment device, The existing equipment can be used effectively and is economical.

  Moreover, in the waste water treatment system 1A in the above-described embodiment, the case where the waste water treatment apparatus 100 having a configuration in which the first treatment tank 110 and the second treatment tank 120 are alternately replaced with the adsorption tank and the desorption tank is illustrated. However, a waste water treatment apparatus having a different configuration may be employed. Hereinafter, an example thereof will be described with reference to FIGS.

  2 and 3 are schematic views showing examples of other waste water treatment apparatuses that can be used in the waste water treatment system according to the present embodiment. 2 and 3, only the adsorbent provided in the waste water treatment apparatus and the components arranged in the vicinity of the adsorbent are shown, and the other components are not shown.

  FIG. 2 shows a case where an adsorbent 150 having a cylindrical outer shape is used. As shown in FIG. 2, when using an adsorbent 150 having a cylindrical outer shape, a rotating shaft 161 is provided at the axial center of the adsorbent 150 configured to allow fluid to flow in the axial direction. The rotary shaft 161 is rotationally driven by an actuator or the like. Then, piping lines L1 to L4 (see FIG. 1) not shown in FIG. 2 are connected in proximity to both axial end surfaces of the adsorbent 150, and a portion for adsorbing a part of the adsorbent 150 ( 2 is used as a portion (denoted by reference numeral 151 in FIG. 2). That is, in the portion indicated by reference numeral 151 of the adsorbent 150, waste water containing an organic compound is introduced from one side in the axial direction, and primary treated water is derived from the other in the axial direction. In the portion indicated by 152, the heating gas is introduced from one side in the axial direction, and the desorption gas is led out from the other side in the axial direction.

  Here, in the waste water treatment apparatus shown in FIG. 2, the adsorbent 150 rotates at a predetermined speed in the direction of arrow A in FIG. As a result, the portion where the adsorption process of the adsorbent 150 is completed moves to the zone where the desorption process is performed, and the portion where the desorption process of the adsorbent 150 is completed moves to the zone where the adsorption process is performed. Therefore, in the waste water treatment apparatus, the adsorption process and the desorption process are simultaneously performed, and the cleaning process can be continuously performed.

  FIG. 3 shows a case where an adsorbent 170 having a cylindrical outer shape is used. As shown in FIG. 3, when using an adsorbent 170 having a cylindrical outer shape, for example, a unit adsorption unit 175 surrounded by a metal frame 185 so that fluid can flow in the radial direction. Are arranged in the circumferential direction into a cylindrical shape, and this is rotationally driven around the axis by an actuator (not shown). Then, piping lines L1 to L4 (see FIG. 1) not shown in FIG. 3 are connected in the vicinity of the adsorbent 170, and a portion for adsorbing a part of the unit adsorption unit of the adsorbent 170 (FIG. 3). In FIG. 3, the other part of the unit adsorption unit is used as a part (denoted by reference numeral 172 in FIG. 3). That is, in the unit adsorption unit denoted by reference numeral 171 of the adsorbent 170, waste water containing an organic compound is introduced from the outside in the radial direction, and the primary treated water is led out toward the inside in the radial direction, toward one of the axial directions. A heated gas is introduced into the unit adsorption unit indicated by reference numeral 172 of the adsorbent 170 from the inside in the radial direction via the introduction pipe 181, and the desorption gas is led out toward the outside in the radial direction. It will be discharged through the tube 182.

  Here, in the waste water treatment apparatus shown in FIG. 3, the adsorbent 170 rotates stepwise at a predetermined speed in the direction of arrow A in the figure around the axis. Thereby, the unit adsorption unit for which the adsorption process of the adsorbent 170 is completed moves to the zone for performing the desorption process, and the unit adsorption unit for which the desorption process of the adsorbent 170 has been completed moves to the zone for performing the adsorption process. become. Therefore, in the waste water treatment apparatus, the adsorption process and the desorption process are simultaneously performed, and the cleaning process can be continuously performed.

  2 and 3, when the adsorbents 150 and 170 having the shapes shown in FIGS. 2 and 3 are used, the adsorbents 150 and 170 are made of a granular material or a fibrous material. Although it is good, it is still more preferable if it comprises what has a honeycomb-like structure. This is because the adsorbents 150 and 170 are made of a honeycomb-like structure, so that the pressure loss can be kept extremely low, the processing capacity is increased, and clogging due to solid matter such as dust is generated. This is because it can be kept relatively low.

(Embodiment 2)
FIG. 4 is a schematic diagram showing the configuration of the wastewater treatment system according to Embodiment 2 of the present invention. In FIG. 4, illustration of the same parts as the waste water treatment system 1A in the first embodiment of the present invention is omitted. Below, with reference to this FIG. 4, the structure of the waste water treatment system 1B in this Embodiment is demonstrated.

  As shown in FIG. 4, the wastewater treatment system 1 </ b> B in the present embodiment is different from the above-described wastewater treatment system 1 </ b> A in the first embodiment of the present invention in the configuration of the wastewater treatment apparatus 100. In the wastewater treatment system 1B in the present embodiment, a piping line L10 for introducing gas into the wastewater treatment apparatus 100 is connected to the piping line L2 for introducing heated gas into the wastewater treatment apparatus 100. Valves V109 and V110 for switching the connection / disconnection state of the piping lines L2 and L10 to the waste water treatment apparatus 100 are provided in the piping lines L2 and L10, respectively. In the wastewater treatment system 1B in the present embodiment, a piping line L12 for discharging the removed wastewater from the wastewater treatment device 100 is connected to the piping line L4 for discharging the desorption gas from the wastewater treatment device 100. In addition, valves V111 and V112 for switching the connection / disconnection state of the piping lines L4 and L12 to the waste water treatment apparatus 100 are provided in the piping lines L4 and L12, respectively. The other end of the piping line L12 is connected to a piping line L1 for introducing wastewater into the wastewater treatment apparatus 100.

In the wastewater treatment apparatus 100 of the wastewater treatment system 1B in the present embodiment, a dehydration process (purge process) is performed between the adsorption process and the desorption process. Specifically, as in the case of the wastewater treatment system 1A in the first embodiment of the present invention described above, in the wastewater treatment apparatus 100, the opening and closing of the valves V101 to V108 is operated to operate the first treatment tank 110 and The second treatment tank 120 is alternately switched to the adsorption tank and the desorption tank. When the second treatment tank 120 is switched to the desorption tank, first, the desorption tank, the piping line L10 and the piping line L12 are connected, and the piping line L10 is connected. A dehydration process is performed to blow off excess wastewater adhering to the surface of the adsorbent by introducing gas into the desorption tank and sprayed onto the adsorbent, and the removed wastewater blown off passes through the piping line L12 and the piping line L1. The wastewater treatment apparatus 100 is supplied again. Then, after the dehydration process is performed for a predetermined time, the connection between the desorption tank and the piping line L10 and the piping line L12 is released, and the piping line L11 and the piping line L4 are connected to the desorption tank and the desorption process is performed.
The gas introduced into the desorption tank during the dehydration process is preferably a high temperature and low humidity gas. For example, it is preferable to use dry air heated to a predetermined temperature. .

  By adopting the configuration as in the wastewater treatment system 1B in the present embodiment described above, the effect obtained when the configuration as in the wastewater treatment system 1A in the first embodiment of the present invention described above is employed. In addition, since the desorption efficiency of the organic compound from the adsorbing elements 111 and 121 is greatly increased as an effect of adding the dehydration treatment, there is an effect that the wastewater treatment system capable of cleaning wastewater more efficiently and stably can be obtained. can get. In addition, in this Embodiment mentioned above, although the case where it comprised so that the removal waste_water | drain discharged | emitted from the waste water treatment apparatus 100 might be supplied to the said waste water treatment apparatus 100 again was demonstrated, the said removal waste_water | drain was demonstrated. May be configured to be cleaned by separately using a wastewater treatment apparatus or the like equipped with an exchangeable adsorption element.

(Embodiment 3)
FIG. 5 is a schematic diagram showing the configuration of the waste water treatment system according to Embodiment 3 of the present invention. Below, with reference to this FIG. 5, the structure of the waste water treatment system 1C in this Embodiment is demonstrated.

  As shown in FIG. 5, the wastewater treatment system 1 </ b> C in the present embodiment mainly includes a wastewater treatment device 100, an activated sludge treatment device 200, and a combustion device 300.

  The combustion apparatus 300 is an apparatus for combusting the desorbed gas discharged from the waste water treatment apparatus 100 for oxidative decomposition, and is connected to the piping lines L4, L13, L14, and L15. The combustion apparatus 300 includes a heat exchanger 310 and a heating furnace 320. The heat exchanger 310 is for preheating the desorption gas introduced into the heating furnace 320 in advance. This is for burning the desorption gas introduced using the electric heater 321. The piping line L4 is a piping line for supplying the desorption gas discharged from the waste water treatment apparatus 100 to the heat exchanger 310, and the piping line L13 is used for supplying the desorption gas preheated by the heat exchanger 310 to the heating furnace 320. It is a piping line for introduction. In addition, the piping lines L14 and L15 are piping lines for discharging cracked gas generated when the desorption gas burns in the heating furnace 320 to the outside via the heat exchanger 310.

  The type of the combustion apparatus 300 is not particularly limited. For example, a direct combustion apparatus that directly oxidatively decomposes the desorption gas at a high temperature of 650 to 800 ° C. or a desorption gas using a platinum catalyst or the like is used. A catalytic combustion device that oxidatively decomposes by catalytic oxidation reaction, a heat storage direct combustion device that performs direct oxidative decomposition economically while performing heat recovery using a heat storage body, and a combination of a platinum catalyst and a heat storage body efficiently It is possible to use a regenerative catalytic combustion apparatus that oxidizes and decomposes the desorbed gas through a catalytic oxidation reaction. By decomposing the desorption gas using the combustion device 300, harmful organic compounds are completely removed.

  As shown in FIG. 5, in the wastewater treatment system 1C in the present embodiment, the desorption gas discharged from the wastewater treatment apparatus 100 is sent to the combustion apparatus 300 via the piping line L4 and burned in the heating furnace 320. It is oxidatively decomposed. The cracked gas generated in the heating furnace 320 is discharged from the combustion apparatus 300 via the piping line L14, the heat exchanger, and the piping line L15. This cracked gas is harmless to the human body mainly containing carbon dioxide and water vapor.

  By using the wastewater treatment system 1C as described above, the desorption gas discharged from the wastewater treatment apparatus 100 can be rendered harmless, and the system is completed as wastewater treatment.

  The characteristic configurations of the wastewater treatment systems 1A, 1B, and 1C according to the first to third embodiments of the present invention described above can be combined with each other. For example, the waste water treatment apparatus including the adsorbents 150 and 170 configured as shown in FIGS. 2 and 3 is applied to the waste water treatment apparatus 100 of the waste water treatment systems 1B and 1C according to the second and third embodiments of the present invention. Also good. In this case, a zone for performing a dehydration process is provided in a zone for performing the desorption process of the adsorbents 150 and 170, and a portion of the adsorbent 150 and 170 located in the zone for performing the dehydration process. The above-described piping lines L11 and L12 are connected in proximity to each other, and the wastewater treatment apparatus 100 is configured so that the dehydration process is performed between the adsorption process and the desorption process.

  Moreover, in Embodiment 1 to 3 of this invention demonstrated above, it demonstrates by exemplifying the continuous activated sludge processing apparatus with which a process is performed continuously as an activated sludge processing apparatus with which a waste water treatment system is equipped. Although performed, it is naturally possible to use a batch activated sludge treatment apparatus in which the treatment is performed batchwise. In Embodiments 1 to 3 of the present invention described above, the activated sludge treatment device provided in the wastewater treatment system has been described as an example of performing solid-liquid separation using a sedimentation tank. In addition, various configurations such as a membrane separation using a membrane provided in an aeration tank can be used. As described above, the activated sludge treatment apparatus provided in the wastewater treatment system to which the present invention is applicable may be of any type.

  In the first to third embodiments of the present invention described above, the description has been made without particularly showing the components such as the fluid conveying means such as the pump and the fan and the fluid storing means such as the storage tank. What is necessary is just to arrange | position a component in an appropriate position as needed.

  As described above, the embodiments disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

Hereinafter, the present invention will be described in more detail with reference to Examples of Embodiment 3, but the present invention is not limited to these Examples.
The evaluation was performed by the following method.
(BET specific surface area)
The BET specific surface area was measured by measuring the amount of nitrogen adsorbed on the sample when the relative pressure was raised in the range of 0.0 to 0.15 in the atmosphere of the boiling point of liquid nitrogen (-195.8 ° C), and a BET plot. Was used to determine the surface area (m ² / g) per unit mass of the sample.
(Pore volume)
The pore volume was measured by a nitrogen gas adsorption method at a relative pressure of 0.95.
(Average pore diameter)
The average pore diameter was determined by the following formula.
dp = 40000 Vp / S (where dp: average pore diameter (径))
Vp: pore volume (cc / g)
S: BET specific surface area (m ² / g)
(Organic compound removal effect)
Wastewater discharged from the ester polymerization production facility was used as raw water. The waste water mainly contains 1,4-dioxane 1000 mg / L, acetaldehyde 14000 mg / L, and ethylene glycol 5000 mg / L. The amount of drainage is 10 L / hr, and the amount of each solvent discharged is 10,000 mg / hr of 1,4-dioxane, 140000 mg / hr, and 50000 mg / hr. Water at a temperature of 30 ° C. was flowed at a space velocity (SV) of 5, and the concentrations of 1,4-dioxane, ethylene glycol and acetaldehyde in and out of a wastewater treatment device, activated sludge treatment device, and combustion device after 500 hours of operation were measured. Solvent discharge was calculated to confirm the removal effect.
(Solvent concentration evaluation)
The water concentration and gas at the inlet and outlet were analyzed and measured by gas chromatography.

<Example 1>
An adsorbing element having an average pore diameter of 17.1 mm, an activated carbon fiber having a BET specific surface area of 1500 m ² / g and a total pore volume of 0.47 m ³ / g as an adsorbent for a wastewater treatment apparatus and a thickness of 150 mm and a weight of 200 g. 2 were installed and installed in the wastewater treatment device of the damper switching type in FIG. 2, and the raw water was introduced so as to have a treated water amount of 10 L / hr to obtain primary treated water.

Next, outside air was used as the gas during the dehydration process of the wastewater treatment apparatus, and the wind speed of dehydration was set to 50 cm / sec. 130 ° C. air was used as the heating gas in the desorption process, and the wind speed for desorption was 50 cm / sec. The adsorption cycle in the adsorption step was 60 min, the dehydration time in the dehydration step was 5 min, the desorption time in the desorption step was 55 min, and a switching cycle was set. As shown in Table 1, the 1,4-dioxane concentration in the primary treated water at that time was 300 mg / hr, and the removal rate was 97%. However, the acetaldehyde and ethylene glycol concentrations were 126000 mg / hr and 45000 mg / hr, respectively, with a removal rate of about 10%.
Further, as shown in Table 3, the concentration of each solvent in the desorption gas was 1,4-dioxane 200 ppm, acetaldehyde 1800 ppm, and ethylene glycol 400 ppm.

  The water purified by the waste water treatment apparatus of this example was able to treat 1,4-dioxane with an efficiency of about 97% even after 500 hours. Since the adsorption and desorption were performed continuously, the treatment was stable and highly efficient without any degradation in performance.

  Next, it consists of a raw water conditioning tank with a capacity of 600L, a dilution tank capacity of 75L, two carrier flow aeration tanks with a capacity of 1250L, two activated sludge tanks with a capacity of 1250L, and a sedimentation tank with a capacity of 2500L Using the activated sludge treatment apparatus of FIG. 5, the primary treated water discharged from the waste water treatment apparatus was introduced at a supply rate of 10 L / hr to obtain secondary treated water. The carrier flow aeration tank was charged with 125 L of a polyvinyl alcohol crosslinked gel carrier (diameter: about 4 mm). In addition, since the organic compound concentration in the primary treated water is high and the load on microorganisms is high, it is diluted 20 times with industrial water supplied from a dilution tank, and 200 L / in a carrier flow aeration tank and an activated sludge tank. Introduced in hr. Table 2 shows the concentrations and amounts of the secondary treated water at 500 hours from the start of operation. Since the 1,4-dioxane concentration is a hardly biodegradable organic solvent, the amount of 1,4-dioxane in the secondary treated water was 300 mg / hr and was not reduced. However, highly biodegradable ethylene glycol and acetaldehyde were significantly reduced to 400 mg / hr and 200 mg / hr, respectively, and could be treated well.

Next, 0.4 L of platinum catalyst is installed in the combustion apparatus of FIG. 5 as a catalyst of the combustion apparatus, and the desorption gas discharged from the waste water treatment apparatus is supplied at an air volume of 0.4 Nm ³ / min. After raising the temperature to 300 ° C. by a preheating heater, the catalyst was brought into contact with the catalyst, and the solvent in the desorption gas was oxidized and decomposed by the catalyst to obtain a cracked gas. Table 4 shows the concentration of each solvent in the cracked gas 500 hours after the start of operation. The 1,4-dioxane, acetaldehyde, and ethylene glycol concentrations in the cracked gas were each 1 ppm or less and could be treated satisfactorily. The average temperature of the cracked gas is 420 ° C., and as shown in FIG. 5, when the gas is passed through a heat exchanger and used for preheating the gas supplied to the combustion device, the amount of power required for using the preheating heater is low. Preheating was possible with a very low power consumption of 3 kWh.

<Comparative Example 1>
FIG. 5 comprising a 600 L raw water conditioning tank, a 75 L dilution tank capacity, two carrier flow aeration tanks each having a capacity of 1250 L, two activated sludge tanks having a capacity of 1250 L, and a sedimentation tank having a capacity of 2500 L Using an activated sludge treatment apparatus, raw water was introduced at a supply rate of 10 L / hr to obtain treated water. The carrier flow aeration tank was charged with 125 L of a polyvinyl alcohol crosslinked gel carrier (diameter: about 4 mm). In addition, since the organic compound concentration in the raw water is high and the load on microorganisms is high, it is diluted 20 times with industrial water supplied from a dilution tank, and 200 L / hr in a carrier flow aeration tank and an activated sludge tank. Introduced in. Table 1 shows the concentration and amount of treated water at 500 hours from the start of operation. Highly biodegradable ethylene glycol and acetaldehyde were significantly reduced to 600 mg / hr and 400 mg / hr, respectively, and could be processed satisfactorily. However, since the 1,4-dioxane concentration is a hardly biodegradable organic compound, the amount of 1,4-dioxane in the treated water was 10000 mg / hr and was not reduced.

Next, an activated carbon fiber having an average pore diameter of 17.1 mm, a BET specific surface area of 1500 m ² / g and a total pore volume of 0.47 m ³ / g is used as an adsorbent for the wastewater treatment apparatus, and the weight is 200 g with a thickness of 150 mm. Two adsorbing elements were prepared and installed in a wastewater treatment device with a damper switching system, and the primary treated water discharged from the activated sludge device was introduced so that the amount of treated water reached 200 L / hr to obtain secondary treated water. It was.

Next, outside air was used as the gas during the dehydration process of the wastewater treatment apparatus, and the wind speed of dehydration was set to 50 cm / sec. 130 ° C. air was used as the heating gas in the desorption process, and the wind speed for desorption was 50 cm / sec. The adsorption cycle in the adsorption step was 60 min, the dehydration time in the dehydration step was 5 min, the desorption time in the desorption step was 55 min, and a switching cycle was set. The concentration of 1,4-dioxane in the secondary treated water at that time is 5000 mg / hr, acetaldehyde 550 mg / hr, and ethylene glycol 350 mg / hr. As shown in Table 2, when compared with Example 1, especially 1,4 -The treatment efficiency of dioxane was significantly reduced.
Moreover, as shown in Table 3, the concentration of each solvent in the desorption gas was 1,4-dioxane 100 ppm, acetaldehyde 100 ppm, and ethylene glycol 50 ppm.

Next, 0.4 L of platinum catalyst is installed in the combustion apparatus of FIG. 5 as a catalyst of the combustion apparatus, and the desorption gas discharged from the waste water treatment apparatus is supplied at an air volume of 0.4 Nm ³ / min. After raising the temperature to 300 ° C. by a preheating heater, the catalyst was brought into contact with the catalyst, and the solvent in the desorption gas was oxidized and decomposed by the catalyst to obtain a cracked gas. Table 4 shows the concentration of each solvent in the cracked gas 500 hours after the start of operation. The 1,4-dioxane, acetaldehyde, and ethylene glycol concentrations in the cracked gas were each 1 ppm or less and could be treated satisfactorily. However, the average temperature of the cracked gas is 320 ° C., and as shown in FIG. 5, when the gas is passed through the heat exchanger and used for preheating the gas supplied to the combustion device, the amount of electric power necessary for using the preheating heater is low. It was 15 kWh, and 5 times the amount of electric power was required for preheating as compared with Example 1.

  1A, 1B, 1C Wastewater treatment system, 100 Wastewater treatment device, 110 First treatment tank, 111 adsorption element, 120 Second treatment tank, 121 adsorption element, 150 adsorption material, 161 rotating shaft, 170 adsorption material, 175 unit adsorption unit , 181 inlet pipe, 182 outlet pipe, 185 frame, 200 activated sludge treatment apparatus, 210 aeration tank, 211 aeration apparatus, 220 sedimentation tank, 300 combustion apparatus, 310 heat exchanger, 320 combustion furnace, 321 electric heater, L1 L15 piping line, V101 to V112 valves.

Claims (5)

A wastewater treatment system for purifying wastewater by removing organic compounds from wastewater containing organic compounds,
It includes an adsorbing element that adsorbs an organic compound by contacting wastewater containing the organic compound and desorbs the adsorbed organic compound by contacting heated gas, and supplies the organic compound by supplying wastewater to the adsorbing element. A wastewater treatment device that adsorbs to an adsorption element and discharges it as primary treated water, and supplies a heated gas to the adsorption element to desorb the organic compound from the adsorption element and discharge it as a desorption gas containing the organic compound;
It has an activated sludge containing microorganisms that decompose organic compounds and is connected to the wastewater treatment device, and decomposes the organic compounds by the microorganisms by bringing the primary treated water discharged from the wastewater treatment device into contact with the activated sludge. And an activated sludge treatment device that is removed and discharged as secondary treated water,
The waste water treatment apparatus continuously moves a portion where the adsorption element has been desorbed to a portion where adsorption processing is performed and moves a portion where the adsorption element is completed to a portion where desorption processing is performed. Wastewater treatment system that can treat primary treated water.   The wastewater treatment system according to claim 1, wherein the wastewater treatment device blows off excess wastewater adhering to the adsorption element by blowing gas onto the adsorption element and discharges it as removed wastewater.   The wastewater treatment system according to claim 2, wherein the removed wastewater discharged from the wastewater treatment device is again supplied to the wastewater treatment device as wastewater.   The wastewater treatment system according to any one of claims 1 to 3, wherein the adsorption element includes at least one member selected from the group consisting of activated carbon, activated carbon fiber, and zeolite.   The wastewater treatment according to any one of claims 1 to 4, further comprising a combustion device connected to the wastewater treatment device and combusting the desorption gas discharged from the wastewater treatment device to oxidatively decompose and discharge the decomposition gas. system.