JP5951533B2 - Method and apparatus for recovering phosphorus from waste water containing phosphorus - Google Patents

Description

  Embodiments of the present invention relate to a method for recovering phosphorus from phosphorus-containing wastewater and an apparatus therefor.

  Urban sewage or organic wastewater often contains phosphorus, and such phosphorus-containing organic wastewater flows into closed waters of inner bays such as Tokyo Bay and lakes such as Lake Biwa, causing phosphorus. There is a problem of eutrophication as a substance. On the other hand, phosphorus is an important resource especially as a fertilizer source for agricultural crops, but Japan does not produce phosphorus ore and relies on imports.

  Therefore, if phosphorus can be efficiently recovered from the phosphorus-containing wastewater as described above and recycled, the above-mentioned eutrophication problem can be solved, and phosphorous resources can be self-supported in Japan. it can.

In order to remove phosphorus from wastewater, a coagulation precipitation method and a crystallization dephosphorization method using various metal salts have been conventionally used. However, the coagulation sedimentation method has a very high chemical cost for Al salts, Fe salts, Ca salts and the like, and the treatment of the generated precipitates is a big problem. The crystallization dephosphorization method is a method of efficiently converting phosphorus to hydroxylapatite by using a seed crystal of hydroxylapatite and removing this (HAP method). Although the generated precipitate is reduced, HCO _{3 in} the solution is used. ^- the ion inhibits crystallization, HCO ₃ and once acidic ^- after removal of the need to return the pH to a weakly alkaline side. For this reason, the running cost by a chemical | medical agent becomes large like a coagulation sedimentation method.

  In view of such problems, Patent Document 1 adsorbs phosphorus by contacting micrococcus-like bacteria having polyphosphate accumulation ability with phosphorus-containing wastewater under aerobic conditions, and puts the bacteria under anaerobic conditions. Attempts have been made to recover phosphorus in wastewater by utilizing the property of releasing adsorbed phosphorus. However, the method described in Patent Document 1 has a problem that phosphorus in wastewater cannot be recovered with high efficiency.

  Further, Patent Document 2 is obtained by using a microorganism that desorbs phosphorus through an anaerobic process and an aerobic process, obtaining sludge containing phosphorus, concentrating the sludge, and releasing phosphorus from the concentrated sludge. In addition, a method is disclosed in which a magnesium salt is added to separated phosphorus-containing separated water to precipitate and recover phosphorus as magnesium ammonium phosphate (MAP).

  However, this method employs a method of returning the desorbed liquid after phosphorus recovery to the water treatment process, but the MAP of fine particles remains in the desorbed liquid without being recovered, and the fine particles circulate in the process. There is a problem that it becomes larger while the pipe is in use, causing the pipe to be blocked. In addition, since impurities other than phosphorus are also collected in a relatively large amount, there is a problem that the MAP recovery rate is relatively reduced and the phosphorus recovery efficiency is low. Furthermore, since the magnesium salt is expensive, there is a problem that the phosphorus recovery cost increases.

JP-A-7-88498 JP-A-9-262599

  An object of the present invention is to recover phosphorus in organic wastewater containing phosphorus at low cost and high efficiency regardless of the concentration.

  The method for recovering phosphorus from phosphorus-containing wastewater according to the embodiment introduces phosphorus from the phosphorus-containing wastewater by introducing the phosphorus-containing wastewater into a precipitation tank, and separating and separating sludge components in the phosphorus-containing wastewater by solid-liquid separation. A first step of obtaining primary treated water; introducing the primary treated water into a reaction tank; and synthesizing polyhydroxyalkanoate in the body using organic matter; and polyphosphoric acid in the body under anaerobic conditions And a second step of dispersing and disposing a carrier carrying phosphorus accumulating bacteria having a function of accumulating phosphorus in the body under aerobic conditions. Also, a third step of setting the inside of the reaction vessel to an aerobic condition, and absorbing and accumulating phosphorus in the phosphorus-containing wastewater by the phosphorus accumulating bacteria, and disposed downstream of the reaction vessel. And a fourth step of obtaining secondary treated water from which phosphorus has been removed from the phosphorus-containing wastewater, while transferring and collecting the phosphorus-accumulating bacteria used in the reaction tank into the recovery tank. .

It is a schematic block diagram of the phosphorus collection | recovery apparatus from the phosphorus containing wastewater in 1st Embodiment. It is a schematic block diagram of the phosphorus collection | recovery apparatus from the phosphorus containing wastewater in 2nd Embodiment. It is a schematic block diagram of the phosphorus collection | recovery apparatus from the phosphorus containing wastewater in 3rd Embodiment. It is a schematic block diagram of the phosphorus collection | recovery apparatus from the phosphorus containing wastewater in 4th Embodiment. It is a schematic block diagram of the phosphorus collection | recovery apparatus from the phosphorus containing wastewater in 5th Embodiment.

  Preferred modes for carrying out the present invention will be described below.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a phosphorus recovery apparatus from phosphorus-containing wastewater in the present embodiment.
The phosphorus recovery apparatus 10 from phosphorus-containing wastewater shown in FIG. 1 settles and separates sludge in the phosphorus-containing wastewater W0, and is disposed downstream of the precipitation tank 11 from the precipitation tank 11 from which sludge has been removed. A phosphorus-containing wastewater and a carrier carrying phosphorus-containing bacteria (hereinafter sometimes referred to as “phosphorus-accumulating bacteria-immobilized carrier”) S are contacted to accumulate phosphorus in the phosphorus-containing bacteria in the body of the phosphorus-accumulating bacteria. It has the reaction tank 12 for performing reaction, and the collection tank 13 which collect | recovers the used support | carrier arrange | positioned in the downstream of the reaction tank 12. FIG. In addition, a storage tank 14 for storing the phosphorus-accumulating bacteria-immobilized carrier S is disposed above the reaction tank 12.

  The bottom of the reaction tank 12 is inclined toward the center, and is configured to have the greatest depth at the center.

  In addition, the storage tank 14 is not an essential component in the present embodiment, and any mode can be adopted as long as the phosphorus storage bacteria-immobilized carrier S can be supplied into the reaction tank 13. For example, the phosphorus storage bacteria immobilization carrier S can be directly dispersed in the reaction tank 12 in which the treated water is held without disposing the storage tank 14.

  Moreover, when the sludge density | concentration in phosphorus containing wastewater W0 is low (for example, 50 mg / L or less), the sedimentation tank 11 can also be abbreviate | omitted. However, by disposing the sedimentation tank 11, the phosphorus in the phosphorus-containing wastewater W0 can be recovered regardless of the sludge concentration in the phosphorus-containing wastewater W0. Therefore, this is an essential component in this embodiment.

  Furthermore, a stirrer is appropriately disposed in the reaction tank 12 to uniformly disperse the phosphorus-accumulating bacteria-immobilized support S in the treated water, thereby increasing the degree of contact between phosphorus in the treated water and the phosphorus-accumulating bacteria-immobilized support S. You can also.

  The shape of the phosphorus accumulating bacterium-immobilized carrier S is not limited to a spherical shape, and may be a square shape or a rod or string shape, depending mainly on the shape of the carrier described below.

  For example, as shown below, the phosphorus accumulating bacterium supported and immobilized on the phosphorus accumulating bacterium immobilization carrier S can be used in the body by using an organic substance such as an organic acid or an amino acid under anaerobic conditions. Polyhydroxyalkanoate) is synthesized, and polyphosphoric acid accumulated in the body at that time is decomposed and discharged as phosphoric acid. Under aerobic conditions, polyphosphoric acid more than the discharged phosphoric acid is accumulated in the body. Although it will not specifically limit if it is a microbe which can do, As a representative strain | stump | stock, the German microevaluation phosphoboras (NBRC 101784) which can be obtained from National Institute for Product Evaluation (NBRC) is mentioned. As these bacteria, those of pure cultured cells can be used, and activated sludge containing the bacteria can also be used.

  Further, the carrier of the phosphorus accumulating bacterium immobilization carrier S is not particularly limited as long as the phosphorus accumulating bacterium is easily supported and fixed by the phosphorus accumulating bacterium, and may be ceramic or metal. However, when such ceramics and metals are used as the carrier, the phosphorus accumulating bacteria adhere to the surface thereof, and therefore, in the phosphorus recovery process shown below, it is detached from the carrier and is discharged into the wastewater in the treatment process. After mixing, it is excreted in the treated water and the use efficiency of the phosphorus accumulating bacteria may be lowered.

  Therefore, preferably, a gel is used as the carrier, and the phosphorus accumulating bacteria are entrapped and immobilized with the gel. In this case, as described above, since the detachment of the phosphorus accumulating bacteria can be suppressed, the use efficiency of the phosphorus accumulating bacteria increases. Further, such a gel has a network structure, and low molecular ions such as phosphate ions in wastewater can freely move within the carrier, so that the phosphorus recovery ability is improved.

  To entrap and fix phosphorus accumulating bacteria on a gel, for example, prepare a suspension of cells and an aqueous solution containing acrylamide monomer, methylenebisacrylamide, N, N, N ', N'-tetramethylethylenediamine. The suspension and the aqueous solution are mixed at about pH 8, and then polymerization is performed using potassium persulfate as a polymerization initiator at the freezing point.

  Further, gels such as sodium alginate gel, calcium alginate gel and agar can also be used. In particular, calcium alginate gel is formed by polymerizing water-soluble sodium alginate and calcium chloride. At that time, by mixing an appropriate amount of a solution containing a phosphate such as calcium phosphate, Since the phosphate is also carried along with the phosphorus accumulating bacteria, the concentration of phosphorus in the carrier can be increased.

  Therefore, when the carrier is used, for example, as a fertilizer after use, even if it is expected that the amount of phosphorus recovered from the wastewater is small and cannot be used as a fertilizer, Since the phosphorus content of can be increased, application to fertilizers and the like can be easily performed.

  Further, when the gel-like carrier as described above is produced, the magnetic substance, for example, iron oxide powder, is mixed in the solution, so that the magnetic substance can be taken into the carrier. . Therefore, in the method for treating phosphorus-containing wastewater described below, the used carrier can be easily recovered from the recovery tank by using a magnet or the like.

Next, a method for treating phosphorus-containing wastewater using the apparatus shown in FIG. 1 will be described.
First, for example, phosphorus-containing wastewater W0 stored in a buffer tank (not shown) is introduced into the sedimentation tank 11 via the pipe 21 by driving the pump 41. Then, the sludge (ss) contained in the phosphorus-containing wastewater W0 settles in the settling tank 11 and is discharged from the bottom of the settling tank 11 to the outside through the pipe 22. The sludge discharged to the outside is appropriately used for general-purpose treatment such as disposal.

  On the other hand, the phosphorus-containing wastewater from which the sludge has been removed is introduced into the reaction tank 12 through the pipe 23 as the primary treated water W1, and further, the phosphorus storage bacteria-immobilized support S stored in the storage tank 14 is used. It introduce | transduces in the reaction tank 12 through the piping 24. FIG. At this time, as described above, the phosphorus storage bacteria-immobilized carrier S is uniformly dispersed in the primary treated water W1 introduced and stored in the reaction tank 12 using a stirrer (not shown) as appropriate.

  Next, the reaction tank 12 is bubbled with oxygen gas or oxygen-containing gas, or oxygen gas is supplied to the pipe 24 from an oxygen cylinder (not shown), and the oxygen gas is dissolved in the primary treated water W1. To aerobic conditions. In the present embodiment, the “aerobic condition” means a state in which oxygen is dissolved and exists in the reaction tank 12.

  The phosphorus accumulating bacteria supported and immobilized on the phosphorus accumulating bacterium immobilization carrier S in the reaction tank 12 accumulates phosphorus in the primary treated water W1 stored in the reaction tank 12 as polyphosphoric acid in the body. The phosphorus in the next treated water W1 is recovered by the phosphorus accumulating bacteria-immobilized carrier S.

In the primary treated water W1, phosphorus generally exists in the form of phosphate ions (PO ₄ ³⁻ or P ₂ O ₇ ⁴⁻ ) or phosphates. Therefore, in the present embodiment, phosphate ions and phosphates are collectively referred to as phosphorus.

  The phosphorus accumulating bacterium-immobilized support S after recovering the phosphorus in the primary treated water W1 is introduced into the recovery tank 13 from the lower part of the reaction tank 12 through the pipe 25 as a used carrier. As is clear from FIG. 1, the bottom of the reaction vessel 12 is inclined toward the center, and is configured to have the greatest depth at the center. Therefore, the used carrier in the reaction tank 12 naturally gathers at the center of the bottom of the reaction tank 12 due to their gravity, so that the collection efficiency of the used carrier through the pipe 25 in the collection tank 13 is improved. .

  Although not specifically described, the recovered and used carrier can be used again as a phosphorus-accumulating bacteria-immobilized carrier S through a predetermined regeneration step, or can be reused as a phosphorus fertilizer.

  On the other hand, the treated water after the phosphorus is recovered from the primary treated water W1 by the phosphorus accumulating bacteria-immobilized carrier S can be discharged into the environment as the secondary treated water or reused as industrial water or the like. You can also.

  As described above, according to the present embodiment, phosphorus in wastewater is removed by the action of phosphorus accumulating bacteria, and the problem of eutrophication caused by phosphorus in rivers and seas is solved. Further, phosphorus is fixed in the removed used carrier, and the carrier is recovered, so that a high concentration of phosphorus can be easily recovered. Furthermore, unlike the physicochemical phosphorus removal method, pretreatment for removing phosphorus and the use of chemicals are not required, so that phosphorus can be recovered at a low cost and with a very low environmental load. Moreover, the phosphorus in the organic wastewater containing phosphorus from a low concentration to a high concentration can be easily removed.

  Therefore, phosphorus in organic wastewater containing phosphorus can be recovered with low cost and high efficiency regardless of its concentration.

(Second Embodiment)
FIG. 2 is a schematic configuration diagram of a phosphorus recovery apparatus from phosphorus-containing wastewater in the present embodiment.
The phosphorus recovery apparatus 20 shown in FIG. 2 is disposed on the bottom of the reaction tank 12 and the blower 15A disposed outside the reaction tank 12 with respect to the phosphorus recovery apparatus 10 in the first embodiment. It is different in that it includes an air diffuser 15B connected by a pipe 27, and the other configurations are the same. The blower 15A and the air diffuser 15B constitute a control device 15 for aerobic and anaerobic conditions.

  Moreover, the same code | symbol is used about the component similar or the same as the phosphorus collection | recovery apparatus 10 shown in FIG.

  In the present embodiment, as described above, since the control device 15 for aerobic and anaerobic conditions including the blower 15A and the diffuser 15B is provided, the inside of the reaction tank 12 is appropriately set to anaerobic conditions or aerobic conditions. be able to.

  For example, when the blower 15A is stopped, oxygen cannot be fed into the reaction tank 12, so that the inside of the reaction tank 12 can be set to an anaerobic condition. Therefore, the polyphosphoric acid accumulated in the body of the phosphorus accumulating bacterium immobilization carrier S becomes phosphate ions (phosphorus) and is discharged out of the body. Next, when the blower 15A is being driven, oxygen can be sent into the reaction tank 12 through the air diffuser 15B, and the reaction tank 12 can be in an aerobic condition. At this time, since the phosphorous-accumulating bacterium-immobilized carrier S takes in phosphate ions (phosphorus) corresponding to polyphosphoric acid that has been discharged under anaerobic conditions, it is introduced and stored in the reaction tank 12. The phosphorus in the primary treated water W1 is recovered by the phosphorus storage bacteria immobilization carrier S.

  In the present embodiment, for example, after the primary treated water W1 is introduced into the reaction tank 12, it is left for 1.5 hours to 3 hours (anaerobic condition), and then the blower 15A is driven for 2 hours to 5 hours. Supply oxygen (aerobic condition). Alternatively, anaerobic conditions and aerobic conditions can be alternately set, and polyphosphoric acid release and phosphorus absorption can be alternately performed a plurality of times.

  In the present embodiment, “aerobic condition” means a state in which oxygen is dissolved and present in the reaction tank 12, and “anaerobic condition” means oxygen and nitric acid in the reaction tank 12. This means a state in which bound oxygen such as nitrous acid is not present.

  Similarly to the first embodiment, the recovered and used carrier is not particularly described, but can be used again as the phosphorus-accumulating bacteria-immobilized carrier S through a predetermined regeneration step. It can also be used for reuse.

  On the other hand, the treated water after the phosphorus is recovered from the primary treated water W1 by the phosphorus accumulating bacteria-immobilized carrier S can be discharged into the environment as the secondary treated water or reused as industrial water or the like. You can also.

  Other features and advantages are the same as in the case of the first embodiment, and thus description thereof is omitted.

  In this embodiment, in addition to the effects of the first embodiment, it is possible to control the time of anaerobic conditions and aerobic conditions, which depends on external factors such as organic matter concentration and temperature in wastewater. Therefore, phosphorus can be stably recovered and removed.

(Third embodiment)
FIG. 3 is a schematic configuration diagram of a phosphorus recovery device from phosphorus-containing wastewater in the present embodiment.
The phosphorus recovery apparatus 30 shown in FIG. 3 is provided with an additional reaction tank 16 on the upstream side of the reaction tank 12 with respect to the phosphorus recovery apparatus 20 in the second embodiment. It is different in that an anaerobic condition is always provided without supplying oxygen, and a storage tank 14 for storing the phosphorus-accumulating bacteria-immobilized carrier S is disposed above the additional reaction tank 16. The additional reaction tank 16 is connected to the reaction tank 12 by a pipe 28.

  The bottom of the additional reaction tank 16 is inclined toward the center, and is configured to have the greatest depth at the center.

  Similarly to the phosphorus recovery apparatus 20 of the second embodiment, the reaction vessel 12 is provided with a blower 15A outside and at the bottom of the reaction vessel 12, and is connected to the blower 15A by a pipe 27. An air diffuser 15B is disposed. However, the reaction tank 12 is different in that oxygen is always supplied to the reaction tank 12 via the blower 15A and the air diffuser 15B, and the aerobic condition is always set.

  In addition, the same code | symbol is used about the component similar or the same as the phosphorus collection | recovery apparatuses 10 and 20 shown in FIG.1 and FIG.2.

  Also in this embodiment, “aerobic condition” means a state in which oxygen is dissolved and present in the reaction tank 12, and “anaerobic condition” means in the additional reaction tank 16. It means a state in which oxygen and bound oxygen such as nitric acid and nitrous acid do not exist.

  In this embodiment, first, for example, phosphorus-containing wastewater W0 stored in a buffer tank (not shown) is introduced into the sedimentation tank 11 via the pipe 21 by driving the pump 41, and the phosphorus-containing wastewater W0. Sludge (ss) contained therein is removed from the phosphorus-containing wastewater W0 by sedimentation separation to obtain primary treated water W1. The sludge settles in the sedimentation tank 11 and is discharged from the bottom of the sedimentation tank 11 to the outside through the pipe 22. The sludge discharged to the outside is appropriately used for general-purpose treatment such as disposal.

  Next, the primary treated water W1 is introduced into the additional reaction tank 16 through the pipe 23, and further, the phosphorus storage bacteria immobilized carrier S stored in the storage tank 14 is added through the pipe 24 to the additional reaction tank. 16 is introduced. At this time, as described above, the additional reaction tank 16 is always anaerobic without supplying oxygen. Therefore, in the additional reaction tank 16, the polyphosphoric acid accumulated in the body of the phosphorus accumulating bacterium immobilization carrier S becomes phosphate ions (phosphorus) and is discharged out of the body.

  Next, the primary treated water W <b> 1 is introduced into the reaction tank 12 through the pipes 29 and 28, and the phosphorus storage bacteria immobilization carrier S is introduced into the reaction tank 12 through the pipe 28. The bottom of the additional reaction tank 16 is also inclined toward the center, and is configured to have the greatest depth at the center. Therefore, the phosphorus storage bacteria-immobilized support S introduced into the additional reaction tank 16 also naturally gathers at the center of the bottom of the additional reaction tank 16 due to their gravity, so that an additional reaction via the pipe 28 is performed. It is possible to easily introduce the phosphorus-storing bacterium-immobilized carrier S from the tank 16 to the reaction tank 12.

  As described above, the reaction tank 12 feeds oxygen into the reaction tank 12 through the blower 15A and the diffuser 15B, and the reaction tank 12 is always in an aerobic condition. Therefore, since the phosphorus storage bacterium immobilization carrier S takes in phosphate ions (phosphorus) corresponding to polyphosphoric acid more than discharged under anaerobic conditions, it is introduced and stored in the reaction tank 12. The phosphorus in the primary treated water W1 is recovered by the phosphorus-accumulating bacteria-immobilized carrier S.

  Similar to the first embodiment, the used carrier is recovered in the recovery tank 13 via the pipe 25, and can be used again as the phosphorus-accumulating bacteria-immobilized support S through a predetermined regeneration step. However, it can be reused as phosphorus fertilizer.

  When it is used again as the phosphorus-accumulating bacteria immobilization carrier S, it is returned to the additional reaction tank 16 through the pipes 31 and 23 as shown in FIG. In this case, polyphosphoric acid is released in the additional reaction tank 16, but in the reaction tank 12 to be introduced next, more phosphate ions (phosphorus) corresponding to the released polyphosphoric acid are taken into the body. Reuse of the storage bacteria immobilization carrier S is realized.

  On the other hand, the treated water after the phosphorus is recovered from the primary treated water W1 by the phosphorus accumulating bacteria-immobilized carrier S can be discharged into the environment as the secondary treated water or reused as industrial water or the like. You can also.

  In addition, the residence time of the primary treated water W1 in the additional reaction tank 16 can be 1.5 to 3 hours, for example, and the residence time of the primary treated water W1 in the reaction tank 12 is, for example, 2 The time can be 5 hours.

  Other features and advantages are the same as in the case of the first embodiment, and thus description thereof is omitted.

  Moreover, in this embodiment, in addition to the effect of 1st Embodiment, since the additional reaction tank 16 of anaerobic conditions is arrange | positioned in the upstream of the reaction tank 12 of aerobic conditions, waste water Even in the case of continuous inflow, the anaerobic and aerobic time can be easily controlled, and the release of phosphorus from the phosphorus-accumulating bacteria-immobilized carrier S and the control of phosphorus accumulation can be easily performed. Moreover, since the water treatment apparatus is a continuous inflow type, the water treatment apparatus is suitable for application to a large amount of water treatment such as a sewage treatment facility as compared with the water treatment apparatus of the second embodiment.

(Fourth embodiment)
FIG. 4 is a schematic configuration diagram of an apparatus for recovering phosphorus from phosphorus-containing wastewater in the present embodiment.
The phosphorus recovery apparatus 40 shown in FIG. 4 is disposed on the bottom of the recovery tank 13 and the blower 17A disposed outside the recovery tank 13 with respect to the phosphorus recovery apparatus 10 in the first embodiment. It is different in that it includes a diffuser pipe 17B connected by a pipe 32, and the other configurations are the same. The blower 17A and the air diffuser 17B constitute a control device 17 for aerobic and anaerobic conditions.

  Moreover, the same code | symbol is used about the component similar or the same as the phosphorus collection | recovery apparatus 10 shown in FIG.

  In the present embodiment, oxygen is always supplied into the recovery tank 13 via the blower 17A and the diffuser 17B, and the inside of the recovery tank 13 is set to an aerobic condition. Therefore, as described in the first embodiment, when the used carrier in which phosphorus is accumulated in the body is collected in the collection tank 13, the phosphorus accumulated in the carrier is discharged out of the body. Can be prevented.

  On the other hand, the treated water after the phosphorus is recovered from the primary treated water W1 by the phosphorus accumulating bacteria-immobilized carrier S can be discharged into the environment as the secondary treated water or reused as industrial water or the like. You can also.

  Other features and advantages are the same as in the case of the first embodiment, and thus description thereof is omitted.

(Fifth embodiment)
FIG. 5 is a schematic configuration diagram of a phosphorus recovery apparatus from phosphorus-containing wastewater in the present embodiment.
A phosphorus recovery apparatus 50 shown in FIG. 5 is provided with a biological treatment tank 18 downstream of the reaction tank 12 and a pipe downstream of the biological treatment tank 18 with respect to the phosphorus recovery apparatus 10 of the first embodiment. The difference is that an additional settling tank 19 is provided via 33, and the other configurations are the same.

  Moreover, the same code | symbol is used about the component similar or the same as the phosphorus collection | recovery apparatus 10 shown in FIG.

  As described above, the phosphorus-accumulating bacterium carrying and immobilizing the phosphorus-accumulating bacteria-immobilized carrier S synthesizes PHA (polyhydroxyalkanoate) in the body using organic substances such as organic acids and amino acids. It has the property of releasing polyphosphoric acid accumulated in the body in the body, and has the characteristic of accumulating polyphosphoric acid in the body more than the discharged phosphoric acid under aerobic conditions. If the concentration of the organic substance in the inside is too high, the organic substance is not consumed by the phosphorus accumulating bacteria but remains in the primary treated water W1 and the secondary treated water W2.

  For this reason, the organic substance density | concentration in the secondary treated water W2 may be too high, and it will become difficult to discharge | emit outside as it is. Therefore, in this embodiment, the biological treatment tank 18 and the additional settling tank 19 are disposed downstream of the reaction tank 12, and the excess organic matter is decomposed into activated sludge in the biological treatment tank 18, and further such activated sludge. Is introduced into an additional settling tank 19, and activated sludge is solid-liquid separated and removed from the secondary treated water W2 to obtain the tertiary treated water W3.

  In this way, the tertiary treated water W3 can be discharged as it is through the pipe 34 because not only phosphorus but also excess organic substances are removed.

  The activated sludge obtained in the additional sedimentation tank 19 is mixed with the sludge obtained in the sedimentation tank 11 via the pipe 35 and is subjected to a general-purpose treatment as appropriate, such as disposal.

  Examples of the microorganism used in the biological treatment tank 18 include Microlunas phosphoboras (NM-1 strain, NM-2 strain). These bacteria are available from (Germany) Product Evaluation Technology Infrastructure (NBRC), and those of pure cultured cells can be used, and activated sludge containing the bacteria can also be used.

  In the present embodiment, even if the phosphorus-containing wastewater W0 having a large variation in organic substance concentration is introduced into the water treatment apparatus 50, stable treatment is possible, and tertiary treated water W3 that meets the discharge standard can be obtained.

  As mentioned above, although several embodiment of this invention was described, these embodiment was posted as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

10, 20, 30, 40, 50 Phosphorus recovery device from phosphorus-containing wastewater 11 Precipitation tank 12 Reaction tank 13 Recovery tank 14 Storage tank 15 Control device for aerobic and anaerobic conditions 15A Blower 15B Air diffuser 16 Additional reaction tank 17 Control device for aerobic and anaerobic conditions 17A Blower 17B Air diffuser 18 Biological treatment tank 19 Additional sedimentation tank 21-29, 31-33 Piping 41 Pump S Phosphorus accumulating bacteria immobilized carrier

Claims (11)

A first step of introducing phosphorus-containing wastewater into a settling tank, and separating and separating sludge components in the phosphorus-containing wastewater by solid-liquid separation to obtain primary treated water containing phosphorus from the phosphorus-containing wastewater;
The primary treated water is introduced into the reaction tank, polyhydroxyalkanoate is synthesized in the body using organic substances, polyphosphoric acid in the body is discharged under anaerobic conditions, and phosphorus is injected into the body under aerobic conditions. A second step of charging a carrier carrying phosphorus accumulating bacteria having a function of accumulating into the reaction vessel, and dispersing the carrier in the reaction vessel ;
A third step of setting the inside of the reaction vessel to an aerobic condition, and absorbing and accumulating phosphorus in the phosphorus-containing wastewater by the phosphorus accumulating bacteria;
The carrier carrying the phosphorus accumulating bacteria used in the reaction tank was transferred to and collected in a recovery tank disposed on the downstream side of the reaction tank, and phosphorus was removed from the phosphorus-containing wastewater. A fourth step of obtaining secondary treated water;
A method for recovering phosphorus from phosphorus-containing wastewater, comprising:   After the second step and before the third step, the anaerobic condition is set before setting the inside of the reaction vessel to an aerobic condition, and the polyphosphorus accumulated in the phosphorus accumulating bacteria The method for recovering phosphorus from phosphorus-containing wastewater according to claim 1, further comprising a fifth step of releasing acid.   The method for recovering phosphorus from phosphorus-containing wastewater according to claim 2, wherein the fifth step and the third step are repeated a plurality of times. An additional reaction tank is provided upstream of the reaction tank, the second step and the fifth step are performed in the additional reaction tank, and the carrier carrying the phosphorus accumulating bacteria releasing polyphosphoric acid. The method for recovering phosphorus from the phosphorus-containing wastewater according to claim 2 , wherein the third step is performed in the reaction tank from the additional reaction tank .   A biological treatment tank is disposed on the downstream side of the reaction tank, and an additional sedimentation tank is disposed on the downstream side of the biological treatment tank to activate the organic matter in the secondary treated water obtained in the fourth step. 2. The method according to claim 1, further comprising a sixth step of decomposing into sludge and separating the activated sludge in the additional settling tank to obtain tertiary treated water from which the organic matter has been removed. To recover phosphorus from wastewater containing phosphorus.   The method for recovering phosphorus from phosphorus-containing wastewater according to any one of claims 1 to 5, wherein the inside of the recovery tank is maintained under aerobic conditions.   The method for recovering phosphorus from phosphorus-containing wastewater according to any one of claims 1 to 6, wherein the carrier contains a magnetic substance. Introducing a phosphorus-containing wastewater, settling and separating sludge components in the phosphorus-containing wastewater by solid-liquid separation, and obtaining a primary treated water containing phosphorus from the phosphorus-containing wastewater;
Introducing the primary treated water, synthesizing polyhydroxyalkanoates in the body using organic matter, discharging polyphosphoric acid in the body under anaerobic conditions, and accumulating phosphorus in the body under aerobic conditions A reaction vessel that disperses and arranges a carrier carrying phosphorus-accumulating bacteria, and absorbs and accumulates phosphorus in the phosphorus-containing wastewater by the phosphorus-accumulating bacteria under aerobic conditions;
A recovery tank that is disposed downstream of the reaction tank and transfers and recovers the carrier carrying the phosphorus accumulating bacteria used in the reaction tank;
An apparatus for recovering phosphorus from phosphorus-containing wastewater, comprising: Comprising an additional reaction vessel set at anaerobic conditions upstream of the reaction vessel;
The apparatus for recovering phosphorus from phosphorus-containing wastewater according to claim 8, wherein the reaction tank is set to an aerobic condition. A biological treatment tank for decomposing organic matter in the secondary treated water into activated sludge downstream of the reaction tank;
An additional settling tank for settling and separating the activated sludge downstream of the biological treatment tank;
The phosphorus collection | recovery apparatus from the phosphorus containing wastewater of Claim 8 characterized by the above-mentioned.   The phosphorus recovery apparatus for phosphorus-containing wastewater according to any one of claims 8 to 10, wherein the carrier contains a magnetic substance.

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