JP6436450B2 - Wastewater treatment method - Google Patents

Description

  The present invention relates to a wastewater treatment method for treating wastewater by purifying an oxide containing organic matter in wastewater to a microorganism group.

  As this type of technology, for example, a technology disclosed in Patent Document 1 below is known. In this technology, in the environment where oxygen is present, the wastewater is treated by flowing down the surface of the carrier on which the microorganisms are supported and flowing down, and then the supply of wastewater is stopped. Repeated starvation to begin endogenous breathing. According to the above technique, it is possible to perform an efficient wastewater treatment by the regeneration treatment that makes the microorganism group starvate.

JP 2011-212566 A

  By the way, a microorganism that performs purification (hereinafter also simply referred to as “purification”) including at least one of oxidation, decomposition, or uptake of an oxide while using oxygen in water may directly use gaseous oxygen. Can not. For this reason, the microorganisms take in and use only oxygen gas (also referred to as “dissolved oxygen” in the present specification) dissolved in water. In addition, among microorganisms that purify oxides in water, there are those that generate undesirable gases when dissolved oxygen is deficient in the water around the microorganisms. Here, in the technique disclosed in Patent Document 1, when the supply of waste water is stopped in order to make the microorganism group starvate, the microorganism group takes in dissolved oxygen from the surrounding water, so that the dissolved oxygen is deficient. However, there has been a problem that undesirable gas may be generated.

  The present invention has been devised to solve the above problems. That is, the present invention avoids the depletion of dissolved oxygen in the water around the microbial group when the microbial group supported on the carrier is starved. It provides a wastewater treatment method that reduces the amount of wastewater.

  In order to solve the above problems, the wastewater treatment method of the present invention takes the following means.

  First, the first invention provides at least the surface or the inside of a carrier on which a microorganism group containing microorganisms that perform purification including at least one of oxidation, decomposition, or uptake of an oxide while using dissolved oxygen in water. This is a wastewater treatment method in which wastewater containing oxides is caused to flow down and the wastewater is treated by reducing the oxides in the wastewater by purifying microorganisms. This waste water treatment method includes a high-concentration oxygen supply step described later and a treated water generation step described later. Here, the high-concentration oxygen supply step supplies high-concentration oxygen, which is a gas containing oxygen having a concentration higher than the concentration of oxygen in the air, into a processing tank in which a carrier is disposed. In this step, the tank is filled with an oxygen atmosphere filled with high-concentration oxygen. Further, in the treated water generating step, waste water is supplied to the upper part of the carrier, and this waste water is transmitted to at least one of the surface or the inside of the carrier to flow down. Then, the microbial group supported on the carrier performs the purification on at least a part of the oxide in the waste water, and the treated water that has flowed down from the carrier due to the reduced concentration of the oxide is discharged into the treatment tank. Discharge outside. Here, the treated water generation step is performed while maintaining the oxygen atmosphere. In the treated water generating step, a purification period described later and a starvation period described later are alternately repeated to maintain a state in which water is transmitted and flowed down to at least one of the surface or the inside of the carrier. Here, the purification period is a period in which the waste water is supplied to the upper part of the carrier and transmitted to at least one of the surface or the inside of the carrier to flow down. In addition, the starvation period is less than the purification period by allowing low-oxide concentration water having a lower concentration of oxide than the wastewater to flow down to at least one of the surface or the inside of the carrier instead of drainage. Is a period in which the supply amount of the oxide is reduced.

  In the present specification, “purification” refers to all actions that are caused biochemically by the presence of a microorganism group and reduce the concentration of a target substance contained in water. That is, in this specification, “purification” of a target substance means that the target substance is metabolized by the microorganism group into another substance, and that the substance discharged from the microorganism group reacts with the target substance to be another substance. And the action of the microorganism group adsorbing the target substance as it is. Further, in the present specification, “oxide” means all substances that can be reduced by purification by a microorganism group. That is, for example, when a microorganism group that can oxidize ammonia nitrogen to nitrite nitrogen or nitrate nitrogen is included in the microorganism group, the ammonia nitrogen is also included in the “oxide” in the present specification. It is.

  The present inventor maintains the oxygen atmosphere and the state in which water flows down for the microorganism group that purifies the water in the oxygen oxide that flows down under an oxygen atmosphere, and supplies the amount of the oxide. As a result, it was found that the ability of microorganisms to be starved to regenerate the purification ability of oxides was reduced, and the present invention was achieved. That is, according to the first aspect of the present invention, dissolved oxygen is dissolved by high-concentration oxygen by causing low-oxide concentration water to flow down to at least one of the surface or the inside of the support while maintaining the oxygen atmosphere during the starvation period. This microbial population can be starved while continuing to supply increased water around the microbial population. This makes it possible to reduce the risk of undesirable gas generation by avoiding the lack of dissolved oxygen in the water surrounding the microorganism group when the microorganism group supported on the carrier is starved. A processing method can be provided.

  Next, according to the second invention, in the first invention described above, a part of the treated water is returned to the upper part of the carrier and circulated to use the treated water as the low oxide concentration water.

  Some microorganisms have both the ability A to purify the oxide A and the ability B to purify the oxide B different from the oxide A. There are things that cannot be used. That is, some microorganisms stop the purification of the oxide B by the ability B while the ability A is purifying the oxide A, and after the purification of the oxide A by the ability A is finished, the ability B There is something that starts purification of the oxide B. When both the oxide A and the oxide B are given to such a microorganism, the microorganism purifies the oxide A as long as the oxide A is present, and after the oxide A disappears. The oxide B is purified. Here, according to the second aspect of the present invention, a part of the treated water that may contain the oxide B that has not been purified in the purification period is returned to the starvation period in which the microorganism group is starved. By flowing down to at least one of the surface or the inside, the oxide B can be purified by the microorganism group. Thereby, the quantity of the oxide contained in the treated water finally discharged | emitted outside can be reduced.

Furthermore, the third invention, heat in the first or second invention described above, the supply of waste water in the purification period, the mixed water this the waste water and the low oxidized concentration water was engaged mixed on a carrier It is done by letting them flow down.

  When the microorganism group purifies the oxide in the water, if the amount of oxide (ie, load) relative to the amount of the microorganism group is relatively large, an overload phenomenon in which purification of the oxide is delayed occurs. Sometimes. Here, according to the third aspect of the present invention, the water that flows down and flows to at least one of the surface or the inside of the carrier in the purification period is a mixed water in which waste water and low-oxidized water are mixed. Thus, it is possible to relatively reduce the amount of oxide in water existing around the microorganism group during the purification period. Accordingly, there is provided a wastewater treatment method capable of performing efficient wastewater treatment by suppressing the occurrence of a partial overload phenomenon in which purification of oxides is delayed and dispersing the load over the entire support. be able to.

  Further, the fourth invention is any one of the first to third inventions described above, wherein the purification rate of the oxide is temporarily increased during the transition from the starvation period to the purification period. This invention is based on the premise that the microorganism group has a property that, after passing through the active state, a steady purification rate is lower than the purification rate in the highly active state. Here, the duration of the highly active state and the purification rate of the oxide while the highly active state continues may vary depending on the length of the starvation period. In the fourth aspect of the invention, the lengths of the purification period and the starvation period are adjusted and set with respect to the total processing time in which the purification period and the starvation period are alternately repeated. This setting is performed so that the amount of oxide purification with respect to the total treatment time is greater than the amount of oxide purification when waste water is supplied for a time equal to the total treatment time.

  In the starvation state where microorganisms start endogenous respiration, when oxides are supplied to the microorganisms, the microorganisms temporarily purify the oxides in order to recover the stock of substances decomposed in the endogenous respiration. There is an example of increasing the speed. In addition, some microorganisms start logarithmic growth that exponentially increases the number of individuals until the inhabitant density reaches a predetermined density, triggered by the supply of oxide in a starved state. Once such a microorganism is supplied with an oxide in a starved state, it temporarily increases the purification rate of the oxide in order to secure the activity energy necessary for the logarithmic growth and substances constituting the living body. It is possible. Here, according to the fourth aspect of the present invention, the purification period and the starvation period are alternately repeated in the treated water generation step, whereby the purification amount of the oxide with respect to the total treatment time is set when the starvation period is not set. The amount of oxide to be purified can be increased. As a result, the amount of oxide to be purified with respect to the total treatment time can be increased to perform efficient wastewater treatment.

It is explanatory drawing which shows schematic structure of the waste water treatment apparatus with which the waste water treatment method concerning one Embodiment of this invention is applied. It is explanatory drawing which shows the waste water treatment method concerning one Embodiment of this invention, and shows the state of the waste water treatment apparatus in the high concentration oxygen supply step of this invention. It is explanatory drawing which shows the waste water treatment method concerning one Embodiment of this invention, and shows the state of the waste water treatment apparatus in a purification period among the treated water production | generation steps of this invention. It is explanatory drawing which shows the waste water treatment method concerning one Embodiment of this invention, and shows the state of the waste water treatment apparatus in the starvation period among the treated water production | generation steps of this invention. It is explanatory drawing which shows the modification of the state of the waste water treatment apparatus in the starvation period shown in FIG. It is a qualitative graph for demonstrating the change of the purification | cleaning speed | rate including the highly active state of the microorganisms group oxide in a purification | cleaning period and a starvation period. It is a graph for demonstrating the density | concentration of the oxide in each of simulated waste_water | drain and treated water in the 1st experiment which sucked up simulated waste_water | drain and used as treated water. It is a graph for demonstrating the density | concentration of the oxide in simulated waste_water | drain in the 2nd experiment which sucked up simulated waste_water | drain and used as treated water. In the said 2nd experiment, it is a graph for demonstrating the density | concentration of the oxide in a treated water.

  Below, the waste water treatment method concerning one Embodiment of this invention is demonstrated. As shown in FIG. 1, this waste water treatment method functions as a control means by using a computer 10A in which a control program, which will be described later, is installed, thereby treating waste water 12A containing an oxide containing organic matter. 10 is a wastewater treatment method to be realized. That is, in the computer 10A, a control program for realizing the wastewater treatment method is recorded in a storage device (not shown) so as to be readable by a computer. The control program causes the computer 10A to function as a control unit of the wastewater treatment apparatus 10, thereby realizing that the wastewater treatment apparatus 10 automatically processes the wastewater 12A without any operator operation.

  In addition, in this specification, the detailed description is abbreviate | omitted about incidental steps, such as the step which stores the waste_water | drain 12A in the waste_water | drain tank 12B (refer FIG. 1). In addition, in the configuration of the waste water treatment apparatus 10, the illustration and detailed description of an incidental configuration such as a support member for suspending the carrier 11 </ b> A inside the processing tank 11 (see FIG. 1) are omitted.

<● Configuration of wastewater treatment equipment (mainly Figure 1)>
As shown in FIG. 1, the waste water treatment apparatus 10 includes a computer 10A, a sealed processing tank 11 having a carrier 11A disposed therein, waste water supply means 12 for supplying waste water 12A to the carrier 11A, and a treatment tank 11 And an oxygen supply device 13 for supplying high-concentration oxygen 13A (see FIG. 2). Here, “high concentration oxygen” refers to a gas containing oxygen having a concentration (for example, about 90 [%]) higher than the concentration of oxygen in the air (about 21 [%]). Further, the waste water treatment apparatus 10 includes a treated water tank 14 that temporarily stores the generated treated water 14A, and a water supply means 15 that supplies low oxide concentration water different from the waste water 12A to the carrier 11A. Yes.

  The carrier 11A is a sponge-like porous body having a large surface area, and supports the microorganism group by attaching the microorganism group to at least one of the surface or the inside thereof. In addition, the carrier 11A is formed in a comb-like shape in which a plurality of triangular prisms extending in the horizontal direction are arranged in the vertical direction so that the carrier 11A can easily come into contact with surrounding gas (for example, high-concentration oxygen 13A shown in FIG. 2). Yes. As shown in FIG. 1, the carrier 11 </ b> A is suspended in the processing tank 11 in a processing space extending in the vertical direction.

  The drainage supply means 12 includes a drainage tank 12B, a drainage suction pump 12C, a drainage suction pipe 12D, a drainage supply pipe 12E, and a mixing valve 12F. The drainage suction pump 12C is controlled by a control signal 10B output from the computer 10A, sucks the drainage 12A stored in the drainage tank 12B by the drainage suction pipe 12D, and pumps it to the drainage supply pipe 12E. The drainage tank 12B stores the drainage 12A discharged irregularly from a drainage source of the drainage 12A (for example, a sewer, not shown) so that the drainage suction pump 12C can suck up the drainage 12A at any time. The mixing valve 12F is a valve capable of pouring the waste water 12A pumped in the waste water supply pipe 12E into the carrier 11A from a position directly above the carrier 11A in the processing tank 11. The mixing valve 12F is connected to the water supply pipe 15F, which is a pipe for supplying the low oxide concentration water described above, and the drainage 12A and the low oxide concentration water are set by the control signal 10C of the computer 10A. The mixed water 11C (see FIG. 3) can be mixed at a certain ratio, and this mixed water 11C can be poured into the carrier 11A. The mixing valve 12F can also pour only the low oxide concentration water into the carrier 11A.

  The oxygen supply device 13 is controlled by a control signal 10D output from the computer 10A, supplies high-concentration oxygen 13A at a predetermined pressure higher than the pressure of the outside air, and high-concentration oxygen 13A (see FIG. 2) in the processing tank 11. ) Can be filled. This high-concentration oxygen 13A dissolves oxygen gas in the water in the processing tank 11 to become exhaust 13B (see FIG. 2), and is discharged to the outside air via the trap 11B. The trap 11B has a configuration in which a pipe extending from the processing tank 11 is inserted into water stretched to a predetermined depth, and the exhaust 13B is discharged from the pipe. Thus, the trap 11B functions as a trap that prevents an external insect or the like (not shown) from entering the inside of the processing tank 11. Here, the exhaust 13B is discharged for the first time when the exhaust 13B pushes down the water of the trap 11B that has entered the pipe to the position of the discharge port from which the pipe is discharged. For this reason, the trap 11B can make the pressure inside the processing tank 11 higher than the pressure of the outside air by setting the water depth difference from the discharge port of the pipe to the water level in the trap 11B.

  The treated water tank 14 is formed as a communication pipe that connects the bottoms of two cylindrical containers opened upward so that water (treated water 14A in FIG. 1) can flow. The treated water tank 14 stores the water in advance so that the treated tank 11 is separated from the outside air by the water. Further, the cylindrical container on one side (left side in FIG. 1) in the treated water tank 14 is connected to the lower part of the treated tank 11 via the treated water introduction pipe 14B, so that the treatment accumulated in the treated tank 11 is stored. Water 14A is introduced. Further, in the cylindrical container on the other side (right side in FIG. 1) of the treated water tank 14, a treated water discharge pipe for discharging treated water 14 </ b> A to the outside at a position above the bottom of the treated water tank 14. 14C is provided. According to this configuration, when waste (for example, a fragment of the carrier 11A that has been peeled off or a group of microorganisms) is mixed in the treated water 14A introduced into the treated water tank 14 (see FIG. 3), the waste becomes water. When it floats, it accumulates on the water surface of the cylindrical container on the one side (left side in FIG. 3), and when the waste sinks in water, it accumulates on the bottom of the treated water tank 14. Thereby, the quantity of the waste contained in the treated water 14A discharged | emitted from the waste water treatment apparatus 10 outside can be reduced.

  The water supply means 15 has a purified water tank 15B, a water suction pump 15C, a purified water suction pipe 15D, a treated water suction pipe 15E, a water supply pipe 15F, and a three-way valve 15G. The purified water tank 15B stores the purified water 15A appropriately supplied from a supply source (for example, water supply, not shown) of the purified water 15A. This purified water 15 </ b> A is water that has a negligible concentration of oxide as compared with the wastewater 12 </ b> A, and corresponds to the “low oxide concentration water” described above. One end of the purified water suction pipe 15D is inserted into the purified water tank 15B, and the other end is connected to the three-way valve 15G. One end of the treated water suction pipe 15E is inserted into the cylindrical container on the other side (right side as viewed in FIG. 5) of the treated water tank 14, and the other end is connected to the three-way valve 15G. The three-way valve 15G is controlled by a control signal 10F output from the computer 10A and switches the connection state of the purified water suction pipe 15D and the treated water suction pipe 15E to the water suction pump 15C. The water suction pump 15C is controlled by a control signal 10E output from the computer 10A, and from the purified water suction pipe 15D (see FIG. 4) or the treated water suction pipe 15E according to the switching of the three-way valve 15G. One of the treated water 14A (see FIG. 3) is sucked up and pumped to the water supply pipe 15F. The water supply pipe 15F is a pipe that realizes supplying water pumped from the water suction pump 15C to the mixing valve 12F and pouring it onto the carrier 11A. If the purified water 15A is water supply water, the concentration of the components of the water supply disinfectant (eg, hypochlorite ions) that weaken the microbial community is reduced by temporarily drawing this water into the water purification tank 15B. Can be made.

<Description of the nature of the microorganism group (FIG. 6)>
The above-mentioned microorganism group is obtained by culturing various microorganisms collected from the natural environment (for example, mud deposited on the bottom of a pond) without dividing the specific microorganisms. It is assumed to have properties. Here, the microorganism group may have all of the following properties by including microorganisms having all of the following properties. In addition, the microorganism group may have all of the following properties as a whole by including a plurality of types of microorganisms having at least one of the following properties. In addition, a microorganism group is one in which none of the microorganisms included in this microorganism group alone has one or more of the following properties, and this property is the cooperation of a plurality of types of microorganisms included in the microorganism group. By being realized by action, the microorganism group as a whole may have all of the following properties.

(Ii) The ability of microorganisms to purify oxides using dissolved oxygen. Note that the microorganism group may also have a property of purifying the oxide without using oxygen.

(B) The microorganism group as a whole has the ability A to purify the oxide A (for example, the ability to decompose amylodextrin into glucose) and the ability B to purify the oxide B different from the oxide A ( For example, it has the ability to break down glucose into carbon dioxide and water, but cannot use ability A and ability B together. That is, the microorganism group pauses the purification of glucose by ability B while purifying amylodextrin by ability A, and starts purification of glucose by ability B when purification of amylodextrin by ability A is completed.

(Ha) When the microorganism group purifies the oxide in the water, if the amount of oxide (that is, load) relative to the amount of the microorganism group is relatively large, an overload phenomenon in which the purification of the oxide is delayed occurs. Nature to make. The overload phenomenon was caused when the concentration of the oxide contained in the water around the microorganism group was relatively high, and a relatively large amount of water containing the oxide flowed into the microorganism group. In any case.

(Ii) A highly active state in which the purification rate of the oxide is temporarily increased when the supply amount of the oxide is returned to the original state for the microorganism group that has been starved by reducing the supply amount of the oxide After going through, the property that it becomes a steady purification rate slower than the purification rate in this highly active state.

  The above property (ii) will be described more specifically. In a normal state in which the microorganism group is constantly supplied with the oxide, the purification rate of the oxide by the microorganism group is stabilized at a substantially constant value as shown in FIG. If the amount of oxide supplied to the microorganism group is reduced from here, the purification rate of the oxide by the microorganism group is reduced according to the supply amount of the oxide, and the microorganism group enters a starvation state in which endogenous respiration starts. . Here, in this specification, “endogenous respiration” means that a starved microorganism avoids starvation death while decomposing a stored substance previously stored in itself. When a microorganism in the microorganism group dies for reasons such as starvation, the dead microorganism is purified as another oxide by other microorganisms in the microorganism group. For this reason, even when no external oxide is given to the microorganism group, the purification rate of the oxide by the microorganism group is not always zero.

  When the supply amount of the oxide to the starved microorganism group is restored, the microorganism group shifts to a highly active state in which the purification rate of the oxide is faster than the normal state before starting endogenous respiration. The oxide (a in Fig. 6) that is excessively purified in this highly active state may be used to re-save the above-mentioned storage material by the microorganism group, or it may be an exponential function until the microorganism group restores the population density. In some cases, it is used for logarithmic growth to increase the number of individuals. Then, the microorganism group that has completed the re-saving and logarithmic growth of the storage substance returns to the normal state. In addition, a loss occurs in the process in which the microbial group decomposes the storage material and performs re-storage. Therefore, a period during which the oxides supplied from the outside to the microorganism group are purified (hereinafter also referred to as “purification period”) and a period during which the microorganism group is in a starved state (hereinafter also referred to as “starvation period”). )), The total amount of oxide that is excessively purified from the transition to the high active state to the return to the normal state (the area of a in FIG. 6) is reduced in the starvation state. It may be greater than the amount of oxide purification (area a in FIG. 6).

<Description of the wastewater treatment method of the present invention (mainly FIGS. 2 to 5)>
Now, when the treatment of the wastewater 12A is executed by the wastewater treatment method of the present invention, an operator who wants to treat the wastewater 12A first prepares the above-described wastewater treatment device 10 and puts it in the treatment tank 11. A carrier 11A carrying a microorganism group is disposed. Next, the worker puts a predetermined amount of water into the treatment tank 11 and the treatment water tank 14 (treated water 14A generated in the treatment of the drainage 12A previously performed in FIG. 1). Here, the water that is put into the treatment tank 11 and the treatment water tank 14 may be water having a lower concentration of oxide than the waste water 12A. For example, the treatment water tank may be the purified water 15A pumped from the purification water tank 15B. 14 may be included. The above steps are also referred to as “setting steps” below.

  Then, the worker activates the computer 10A of the wastewater treatment apparatus 10 and causes the computer 10A to execute the control program described above. As shown in FIG. 2, the computer 10 </ b> A that has started execution of the control program outputs a control signal 10 </ b> D to the oxygen supply device 13 to supply high concentration oxygen 13 </ b> A from the oxygen supply device 13 into the processing tank 11. . At this time, the computer 10A causes the oxygen supply device 13 to supply the high-concentration oxygen 13A at a predetermined pressure higher than the pressure of the outside air, so that the processing tank 11 is filled with the high-concentration oxygen 13A higher than the outside air. Use an oxygen atmosphere. That is, the above step corresponds to the “high concentration oxygen supply step” in the present invention.

  In the high concentration oxygen supply step, since the pressure in the processing tank 11 is higher than the pressure of the outside air, the water surface in the processing water tank 14 is pushed up by the pressure difference with the outside air. For this reason, a part of the water put in the treatment tank 11 and the treatment water tank 14 in the setting step described above is discharged to the outside from the treatment water discharge pipe 14C. Then, the high concentration oxygen 13A having a pressure higher than the outside air in the treatment tank 11 positions the water surface in the treatment water tank 14 at the same height as the lower edge of the treatment water discharge pipe 14C.

  In addition, the computer 10A uses the data stored in advance in the storage device (not shown) and the elapsed time from the time when the oxygen supply device 13 starts the supply of the high concentration oxygen 13A to the present time in the processing tank 11. Determines the timing at which the above-described oxygen atmosphere is reached (hereinafter also referred to as “filling timing”). Then, as shown in FIG. 3, the computer 10 </ b> A outputs a control signal 10 </ b> B to the drainage suction pump 12 </ b> C in accordance with the filling timing, and starts the drainage of the drainage 12 </ b> A by the drainage supply means 12. Further, the computer 10A outputs control signals 10E and 10F to the water suction pump 15C and the three-way valve 15G, respectively, in accordance with the filling timing, thereby starting the suction of the treated water 14A by the water supply means 15. Further, the computer 10A outputs a control signal 10C to the mixing valve 12F in accordance with the filling timing, thereby starting to pour the sucked waste water 12A and the treated water 14A into the carrier 11A as the mixed water 11C. Note that the computer 10A maintains the output of the control signal 10D to the oxygen supply device 13 even after the filling timing, and causes the oxygen supply device 13 to continue supplying the high concentration oxygen 13A.

  By each of the control signals 10B, 10C, 10D, 10E, and 10F, the waste water treatment apparatus 10 supplies the mixed water 11C including the waste water 12A to the upper portion of the carrier 11A while maintaining the oxygen atmosphere described above, and this mixed water 11C. Is allowed to flow down to at least one of the surface or the inside of the carrier 11A and the portion on which the microorganism group is supported. Then, the waste water treatment apparatus 10 purifies at least a part of the oxide contained in the waste water 12A to the microorganism group supported on the carrier 11A so that the concentration of the oxide is lowered and flows down from the carrier 11A. The treated water 14 </ b> A is discharged to the treated water tank 14 outside the treatment tank 11. That is, the above operation corresponds to an operation in the “purification period” in the “treated water generation step” of the present invention, and is hereinafter also referred to as “mixed water supply operation”. According to this mixed water supply operation, the property that the amount of oxygen gas dissolved in water increases according to the oxygen concentration in the gas in contact with the water by making the inside of the processing tank 11 the above-described oxygen atmosphere is utilized. Thus, it is possible to increase the dissolved oxygen in the mixed water 11C. And the waste water treatment apparatus 10 can purify the waste water 12A efficiently, making use of the above-mentioned (ii) property of the microorganism group. In the mixed water supply operation, the waste water treatment apparatus 10 discharges the treated water 14A from the treated water discharge pipe 14C to the outside by the amount of the waste water 12A sucked up from the drain tank 12B by the waste water supply means 12.

  Note that the computer 10A causes the waste water treatment apparatus 10 to alternately and repeatedly execute the mixed water supply operation for realizing the above-described purification period and the purified water supply operation for realizing the above-mentioned starvation period. In other words, the computer 10A first performs the mixed water supply operation so that the microorganism group is in a normal state (see FIG. 6), and then supplies the purified water so that the microorganism group is in a starvation state (see FIG. 6). Repeat the operation. This step corresponds to the “treated water generation step” in the present invention. Through this treated water generation step, the wastewater treatment apparatus 10 efficiently treats the wastewater 12A in the wastewater treatment apparatus 10 by repeatedly setting the microorganism group supported on the carrier 11A to the above-described highly active state (see FIG. 6).

  In the purified water supply operation, as shown in FIG. 4, the computer 10 </ b> A stops the output of the control signal 10 </ b> B and stops the drainage of the drainage 12 </ b> A by the drainage supply unit 12. Further, the computer 10A outputs the control signals 10E and 10F to the water suction pump 15C and the three-way valve 15G, respectively, thereby starting the suction of the purified water 15A by the water supply means 15. Further, the computer 10A outputs a control signal 10C to the mixing valve 12F to start pouring only the sucked purified water 15A into the carrier 11A. The computer 10A maintains the output of the control signal 10D to the oxygen supply device 13 even after the purification end timing, and causes the oxygen supply device 13 to continue supplying the high concentration oxygen 13A.

  By each of the control signals 10C, 10D, 10E, and 10F, the waste water treatment apparatus 10 supplies the purified water 15A to the upper portion of the carrier 11A while maintaining the above-described oxygen atmosphere, and the purified water 15A is supplied to the surface or inside of the carrier 11A. Let it flow down to at least one side. Then, the waste water treatment apparatus 10 causes the purified water 15A to flow down to at least one of the surface or the inside of the carrier 11A instead of the mixed water 11C containing the waste water 12A, thereby reducing the supply amount of the oxide to the microorganism group. Reduce this microbial population to starvation. At this time, the treated water 14A in the treated water tank 14 is discharged to the outside by the amount of the purified water 15A sucked up by the water supply means 15 from the purified water tank 15B, and thus is gradually diluted by the purified water 15A. The purified water supply operation and the mixed water supply operation described above are always maintained at least one of the surface and the inside of the carrier 11A and the state where water is transmitted to the part where the microorganism group is carried and is flowing down. Repeat as you want.

  According to each step described above, the purified water 15A is supplied to the surface of the carrier 11A or inside the carrier 11A while maintaining the oxygen atmosphere during the hunger period in which the supply amount of the oxide to the microbial group is decreased to make the microbial group starvation. Let it flow down to at least one side. For this reason, the waste water treatment apparatus 10 can make this microbial group starved while continuing to supply the purified water 15A in which dissolved oxygen is increased by the high-concentration oxygen 13A around the microbial group. This provides a wastewater treatment method that avoids deficiency of dissolved oxygen in the water around the microbial group when the microbial group is starved, and reduces the possibility of undesirable gas generation. it can.

  Further, according to each step described above, the water that flows down and flows to at least one of the surface or the inside of the carrier 11A in the purification period described above is the mixed water 11C in which the drainage 12A and the treated water 14A are mixed. This reduces the concentration of oxides around the microbial community to reduce the amount of oxide (ie, load) relative to the amount of microbial communities, resulting in the occurrence of partial overloading phenomenon where purification of the oxide is delayed By suppressing the above and distributing the load over the entire carrier, it becomes possible to perform an efficient wastewater treatment. In this case, the treated water 14A functions as “low oxide concentration water” in the third aspect of the present invention.

  Now, in the treated water production | generation step mentioned above, in order to implement | achieve the starvation period mentioned above, the purified water supply operation (refer FIG. 4) mentioned above was performed. However, in the wastewater treatment method of the present invention, a treated water supply operation (see FIG. 5) for supplying treated water 14A as low-oxidized concentration water may be executed in order to realize the above-described starvation period. In this treated water supply operation, the computer 10A is transferred to at least one of the surface or the inside of the carrier 11A by switching the three-way valve 15G to connect the water suction pump 15C and the treated water suction pipe 15E. This water is treated water 14A. In other words, in the treated water supply process, instead of supplying the purified water 15A, a part of the treated water 14A is returned to the upper part of the support 11A and circulated to use the treated water 14A as the low oxide concentration water. It is. According to this treated water supply operation, treated water that may contain an oxide that has not been purified during the purification period (for example, glucose produced by the decomposition of amylodextrin) during the starvation period when the microorganism group is starved. By transferring 14A to at least one of the surface or the inside of the carrier 11A and flowing down, the unoxidized oxide (for example, glucose) can be purified by the microorganism group. Thereby, the quantity of the oxide contained in the treated water 14A finally discharged | emitted outside can be reduced. In the treated water supply operation, the water surface in the treated water tank 14 is positioned at the same height as the lower edge of the treated water discharge pipe 14C. Thereby, the amount of the oxide contained in the treated water 14A discharged to the outside is reduced by continuing the circulation of the treated water 14A while not discharging the treated water 14A to the outside in the treated water supply operation. It can be further reduced.

  By the way, when the treated water 14A that has flowed down from the carrier 11A in the treated water supply operation is repeatedly circulated, the number of times of contact with the high-concentration oxygen 13A filled in the treatment tank 11 at a pressure higher than the outside air is increased. . For this reason, the total amount of oxygen gas dissolved in the treated water 14A repeatedly circulated in the treated water supply operation is increased by repeating the circulation. Thereby, when reducing the quantity of the oxide contained in the treated water 14A by the said treated water supply operation, the total amount of dissolved oxygen which a microorganism group can utilize can be increased. And the quantity of the oxide contained in 14A of treated water can be decreased more utilizing the above-mentioned (ii) property which microorganisms have.

〈Explanation of setting of purification period and hunger period (mainly Fig. 6)〉
Next, how to set the length of the above-described purification period and hunger period will be described mainly with reference to FIG. The high activity state due to the nature of (ii) described above is a state in which, for example, the microorganism group is re-saving the storage material decomposed in the starved state, so the length of time that the high activity state can be sustained and the high activity state The purification rate of the oxide in the state may vary depending on the length of the starvation period during which a part of the microorganism group has starved to death. In this case, the total amount of oxide to be purified in the high activity state may be determined by the length of the starvation period and the duration of the high activity state. Further, the amount of oxide purification (area (a) in FIG. 6) reduced when the microorganism group is starved is the above-described low oxide concentration water (purified water 15A in FIG. 4 or treated water in FIG. 5). 14A) and the length of the starvation period.

  Therefore, in the wastewater treatment method of the present invention, the length of the purification period and the starvation period is adjusted with respect to the total treatment time (see FIG. 6) in which the purification period and the starvation period are alternately repeated. Set. This setting is performed so that the amount of oxide purification with respect to the total treatment time is greater than the amount of oxide purification when waste water is supplied for a time equal to the total treatment time. Thereby, in the treated water generation step described above, the purification period (see FIG. 3) and the starvation period (see FIG. 4 or 5) are alternately repeated, whereby the purification amount of the oxide with respect to the total treatment time is It is possible to increase the purification amount of the oxide with respect to the total processing time by increasing the purification amount of the oxide when the starvation period is not set.

<Explanation of Experiments Proving the Effect of the Present Invention (Mainly FIGS. 7 to 9)>
In addition, this inventor has confirmed the effectiveness of the waste water treatment method of this invention mentioned above by experiment. Hereinafter, this experiment will be described mainly using the graphs of FIGS.

  The present inventor conducted first and second experiments for purifying simulated waste water using a waste water treatment apparatus having the same configuration as the waste water treatment apparatus 10 shown in FIG. In the first and second experiments, the simulated waste water is obtained by adding amylodextrin, which is an organic substance to be oxidized, and nutrient salts and sodium hydrogen carbonate that are not to be oxidized, to the water of the water supply that has been drawn in advance. The melted one was used. At this time, the concentration of amylodextrin in the simulated waste water was adjusted so that the oxygen consumption was 1000 [mg / l]. In the present specification, the “oxygen consumption amount” is expressed by converting the amount of oxygen required when all the oxides in water are oxidized with potassium dichromate into the concentration of dissolved oxygen. It refers to things.

  In the first experiment, the present inventor confirmed that the first invention of the present invention is effective. In the first experiment, first, while maintaining the oxygen atmosphere, only the simulated waste water is caused to flow down at a predetermined flow rate to at least one of the surface and the inside of the carrier and carrying the microorganism group. The simulated waste water was purified to obtain treated water. And how much the oxide was purified and decreased in this treatment was examined by comparing the concentration of dissolved components dissolved in water with respect to each of the simulated waste water and treated water. In the first experiment, when the concentration of the dissolved component of the oxide is evaluated, the dissolved component of the oxidized product is decomposed by microorganisms that decompose the oxidized product through a biochemical reaction using dissolved oxygen. When decomposed, the amount of dissolved oxygen required by the microorganism (in this specification, also referred to as “biochemical oxygen demand of dissolved components”) was used. In other words, the biochemical oxygen demand of the dissolved oxide component corresponds to the concentration of the dissolved oxide component. Moreover, the said 1st experiment was continuously performed, repeating the sampling of simulated waste_water | drain and treated water at a suitable space | interval.

  In the first experiment, as shown in FIG. 7, the biochemical oxygen demand of the dissolved component was reduced to almost one-fourth or less by purifying the simulated waste water to be treated water. Moreover, in the said 1st experiment, when purification | cleaning of the simulation waste_water | drain was continuously performed, the biochemical oxygen requirement amount of the melt | dissolution component in a treated water increased (refer the time range of (t1) of FIG. 7). This means that if the operation of the wastewater treatment apparatus described above is continued under the conditions of the first experiment, the ability of the wastewater treatment apparatus to purify wastewater is reduced.

  Here, after confirming that the biochemical oxygen demand of the dissolved component in the treated water was increased, the present inventor made the waste water treatment apparatus perform the above-described purified water supply operation (see FIG. 4). . This purified water supply operation was performed in each time range T1, T2, T3, and T4 shown in FIG. When the biochemical oxygen demand of dissolved components in the treated water is compared before and after the purified water supply operation, the purified water supply operation is performed when the biochemical oxygen demand of the dissolved components in the treated water is increased (Fig. 7 T1 and T3), it can be seen that the biochemical oxygen demand of dissolved components in the treated water is reduced after the operation. Further, when the purified water supply operation is performed when the biochemical oxygen demand of the dissolved component in the treated water is not increased (see T2 and T4 in FIG. 7), the biochemical of the dissolved component in the treated water after the operation is performed. It can be seen that the oxygen demand is not changed. From here, when the supply of oxides is reduced by maintaining both the oxygen atmosphere and the state in which water flows down against the group of microorganisms that purifies the water oxides flowing down under an oxygen atmosphere, It can be said that the group becomes starved and the purification ability of the oxide is regenerated. The first invention of the present invention that avoids the deficiency of dissolved oxygen in the water around the microorganism group when the microorganism group supported on the carrier is starved is effective. it can.

  Next, the second experiment described above will be described. In this second experiment, the present inventor confirmed that the third invention of the present invention is effective. In the second experiment, first, the flow rate of the simulated waste water is increased to 1.6 times the flow rate in the first experiment described above, and the conditions other than the simulated waste water flow rate are the same as in the first experiment. Thus, the simulated waste water was purified to obtain treated water. The extent to which the oxides were purified and decreased in this treatment was examined by comparing the biochemical oxygen demand of dissolved components in each of the simulated waste water and treated water. In the second experiment, the types and ratios of the oxides contained in each of the simulated waste water and the treated water were also examined.

  In the second experiment, as shown in FIG. 8 and FIG. 9, the biochemical oxygen demand of the dissolved component was reduced to almost one-fourth or less by purifying the simulated waste water to be treated water. . Moreover, in the said 2nd experiment, it turned out that about 36 [%] is glucose among the oxides contained in the treated water produced | generated by flowing down only simulated waste water. This is because, under the conditions of the second experiment, when only the simulated waste water is purified by flowing down to at least one of the surface or inside of the carrier and supporting the microorganism group, the microorganism group mainly converts amylodextrin to glucose. This means that the oxides are purified in a form that decomposes into glucose, and the purification of glucose is delayed.

  Then, this inventor made the wastewater treatment apparatus mentioned above perform the purified water supply operation (refer FIG. 4) only for predetermined time from the timing of (a) shown in FIG. 8 and FIG. Subsequently, until the timing of (b) shown in FIG. 8 and FIG. 9, only the simulated waste water was allowed to flow down under the same conditions as before execution of the purified water supply operation to purify the simulated waste water (not shown). As a result, the biochemical oxygen demand of dissolved components in the treated water was reduced as shown in FIG. 9, but the ratio of glucose in the oxide contained in the treated water was not significantly changed. It was.

  Therefore, the present inventor starts mixing of the treated water into the simulated waste water without changing the flow rate of the simulated waste water from the timing of (b) above, so that the mixed water supply operation by the waste water treatment apparatus (FIG. 3) is performed. Reference) was started. Here, the flow rate of the treated water mixed with the simulated waste water was set to be 5 times the flow rate of the simulated waste water. As a result, the proportion of glucose in the oxide contained in the treated water was reduced from about 36 [%] to about 11 [%]. This is because the purification of glucose was delayed before the mixed water supply operation because a relatively large amount of simulated wastewater containing oxides was present in the microorganism group (for example, the flow rate of 1. in the first experiment described above). This means that a partial overload phenomenon occurred due to the flow down (at a flow rate of 6 times). The partial overload phenomenon is caused by mixing the treated water with the simulated waste water to lower the concentration of the oxide to reduce the amount of oxide (ie, the load) relative to the amount of the microorganism group. Means that it will be resolved. From here, supplying wastewater in the form of mixed water suppresses the occurrence of partial overload phenomenon where the purification of oxides is delayed, and efficient drainage treatment is achieved by dispersing the above load throughout the carrier. It can be said that the third invention of the present invention to be realized is effective.

  The present inventor stopped the simulated waste water supplied in the mixed water supply operation of the second experiment and increased the flow rate of the treated water by 1.5 times to thereby treat the above-described treatment in the waste water treatment apparatus. Water supply operation (refer FIG. 5) was performed. This treatment water supply operation was performed 4 times intermittently in the time range of (c) shown in FIGS. In addition, this inventor made the said waste water treatment apparatus perform the said mixed water supply operation, when not performing the said treated water supply operation in the time range of said (c). As a result, as shown in FIG. 9, the experimental result that the biochemical oxygen demand of the dissolved component in the treated water does not increase depending on the treated water supply operation was obtained.

  The present invention is not limited to the one described in the above-described embodiment, and various changes, additions, and deletions can be made without changing the gist thereof.

  For example, in the mixed water supply operation in the treated water generation step, the waste water sucked up from the drain tank and the purified water sucked up from the purified water tank are mixed to form mixed water, and this mixed water is at least one of the surface or the inside of the carrier. A technique can be employed in which the microorganisms are allowed to flow down to the part where they are carried.

  Further, the timing for shifting from the high-concentration oxygen supply step to the treated water generation step need not be determined from data stored in advance in the storage device of the computer. That is, for example, a sensor that measures the ambient oxygen concentration in the treated water tank and outputs it to a computer is disposed, and the oxygen concentration output from the sensor exceeds a predetermined concentration after the start of the high concentration oxygen supply step. A technique for shifting to the treated water generation step can be adopted.

DESCRIPTION OF SYMBOLS 10 Waste water treatment apparatus 10A Computer 10B Control signal 10C Control signal 10D Control signal 10E Control signal 10F Control signal 11 Processing tank 11A Carrier 11B Trap 12 Waste water supply means 12A Waste water 12B Waste water tank 12C Waste water suction pump 12D Waste water suction pipe 12E Waste water supply pipe 12F Mixing valve 13 Oxygen supply device 13A High concentration oxygen 13B Exhaust 14 Treated water tank 14A Treated water (low oxide concentration water)
14B Treated water introduction pipe 14C Treated water discharge pipe 15 Water supply means 15A Purified water (low oxide concentration water)
15B Water purification tank 15C Water suction pump 15D Water purification pipe 15E Treated water suction pipe 15F Water supply pipe 15G Three-way valve

Claims (4)

At least one of the surface and the inside of the carrier on which a microorganism group including microorganisms that perform purification including at least one of oxidation, decomposition, and uptake of an oxide containing organic matter is used while using dissolved oxygen in water. In the wastewater treatment method for treating the wastewater by reducing the oxide in the wastewater by the purification of the microorganism group by flowing down the wastewater containing the matter,
High concentration oxygen, which is a gas containing oxygen at a concentration higher than the concentration of oxygen in the air, is supplied into the processing tank in which the carrier is disposed, and the processing tank is filled with the high concentration oxygen. A high-concentration oxygen supply step for creating an oxygen atmosphere,
While maintaining the oxygen atmosphere, the wastewater is supplied to the upper part of the carrier, and the wastewater is transferred to at least one of the surface or the inside of the carrier to flow down to the group of microorganisms supported on the carrier. Treated water that causes the purification to be performed on at least a part of the oxide in the waste water, and discharges treated water that has flowed down from the carrier due to a low concentration of the oxide to the outside of the treatment tank. Generation step;
Have
In the treated water generating step, a purification period in which the wastewater is supplied to the upper part of the carrier and is allowed to flow down to at least one of the surface or the inside of the carrier, and the oxidizer rather than the wastewater instead of the wastewater. A starvation period in which the supply amount of the oxide is reduced as compared with the purification period by flowing down the low oxide concentration water having a low content concentration to the surface or at least one of the inside of the carrier. By alternately repeating the above, water is transferred to at least one of the surface or the inside of the carrier and maintained in a flowing state.
Wastewater treatment method. A wastewater treatment method according to claim 1,
By circulating a part of the treated water back to the upper part of the carrier, the treated water is used as the low oxide concentration water.
Wastewater treatment method. A wastewater treatment method according to claim 1 or claim 2,
Supplying the waste water during the purification period is performed by flowing down the mixed water in which the waste water and the low oxidant concentration water are mixed to at least one of the surface or the inside of the carrier.
Wastewater treatment method. A wastewater treatment method according to any one of claims 1 to 3,
Upon transition from the starvation period to the purification period, after passing through a highly active state where the purification rate of the oxide is temporarily increased, a steady purification rate lower than the purification rate in the highly active state is obtained. The microorganism group has the property that the duration of the highly active state and the purification rate of the oxide during the duration of the highly active state vary depending on the length of the starvation period. in the case,
With respect to the total treatment time in which the purification period and the starvation period are alternately repeated, the purification of the oxide is more than the purification amount of the oxide when the waste water is supplied for a time equal to the total treatment time. Adjusting and setting the length of the purification period and the hunger period so that the amount is increased,
Wastewater treatment method.

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