JPH06320190A - Method and device for treating sewage water - Google Patents

Abstract

PURPOSE:To stably treat human waste, various domestic waste water sludge and septic tank sludge in the same facilities by a method wherein, after dewatered homogenization, sewage water is flocculated, the resulting slurry is and the resulting filtrate, together with the human waste, is treated undergoing a biological treating process and a solid-liquid separating process. CONSTITUTION:Septic tank sludge 1 is sent through a water receiving tank 2 and a foreign matter-removing device 3 into an adjusting tank 5 to be homogenized and it is refined in coagulation tanks 6 and 7 by adding an inorganic coagulant 8 and an organic high-molecular flocculant. The sludge is then dewater by a dewater 10 and the resulting filtrate is sent through a reservoir tank 13 into an anaerobic tank 21 together with the human waste 19 remaining after removal of coarse and large solid from human waste 14 and return sludge 20 in order to lower BOD concentration. Then an activated sludge-liquid mixture in the anaerobic tank 21, together with circulating nitrification liquid 22, is sent into a first denitrification tank 23 where part of phosphorus in the liquid is absorbed by the activated sludge and, in a nitrification tank 4 also, ammonia in liquid stream is oxidized into nitric acid. Thereafter, it is treated through a second denitrification tank 25 and a reaeration tank 26 and, after treatment, is discharged through a membrane separating device 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating sewage, and in particular, human waste, septic tank sludge, household wastewater sludge (those containing rich SS such as domestic wastewater drainage pit sludge and building pit sludge). The present invention relates to a method for treating sludge, denitrification, and dephosphorization of human wastewater having different properties in the same facility.

[0002]

2. Description of the Related Art Conventionally, there has been an example in which human waste and septic tank sludge are simultaneously biologically denitrified and dephosphorized by the same treatment device. However, since the SS concentration of septic tank sludge and household wastewater sludge varies greatly, when the amount of septic tank sludge carried into the treatment facility is larger than that of human waste, the load fluctuation on the biological treatment device becomes large, and the conventional technique is stable. Denitrification treatment and dephosphorization treatment cannot be performed.

Biologically treated water of relatively thick sewage such as septic tank sludge is coagulated with an inorganic coagulant to remove residual phosphorus and COD components. Since the alkalinity is high, there is a problem that the amount of (acidic) inorganic coagulant added to reduce the pH to the optimum pH for coagulation is large, and the amount of coagulable sludge that is difficult to dehydrate increases accordingly.

[0004]

Recently, while the amount of urine collected has decreased due to the spread of flushing toilets, septic tank sludge is increasing due to the delay in the spread of sewerage. As a result, in the human waste sewage carried into the human waste treatment facility, the ratio of septic tank sludge has increased, and the problem for the stable treatment has been highlighted. In addition, the same problem as septic tank sludge occurs in the treatment of household wastewater sludge that is carried into human waste treatment facilities. It is an object of the present invention to solve these problems and to provide a wastewater treatment method and device capable of efficiently and stably treating night soil, septic tank sludge, and domestic wastewater sludge in the same facility.

[0005]

In order to solve the above-mentioned problems, the present invention provides a method for treating two or more kinds of sewage characterized by including the following steps (a) to (g). . (A) an adjusting step of homogenizing sewage containing rich SS such as septic tank sludge and household wastewater sludge, (b) an aggregating step of adding an aggregating agent to the effluent from the adjusting step, and performing an aggregating treatment, (C) a dehydration storage step of dehydrating the agglomerated slurry flowing out from the aggregating treatment step and storing an obtained dehydrated filtrate, (d) raw urine and stored water of the dehydration storage step, wherein the stored water amount> raw urine A biological treatment step of biologically performing denitrification and dephosphorization treatment under the condition of quantity and a predetermined proportion thereof, (e) the activated sludge slurry from the biological treatment step. A solid-liquid separation step of performing solid-liquid separation into activated sludge and treated water, (f) transferring excess activated sludge in the solid-liquid separation step to the adjustment step of (a) and / or the aggregation treatment step of (b) (G) the treated water of the solid-liquid separation step, Advanced treatment step of treating the.

Further, in the above-mentioned treatment method, a concentration / separation step for separating the condensed slurry flowing out from the aggregation treatment step (b) into concentrated sludge and separated water before dehydration is provided, and the concentrated sludge is dehydrated and dehydrated. The liquid and the separated water may be stored to form a dehydration storage step. Further, as the solid-liquid separation step, a membrane separating means may be used, which is immersed in the liquid of the biological treatment step, or may be provided at a later stage of the biological treatment step. In addition, the adjusting step (a) has a function of the adjusting tank and a function of homogenizing, and water flow, air, mechanical stirring, or the like can be used as a means for homogenizing, and when air is used, May be subjected to aeration and nitrification denitrification in this adjustment step. Aeration and nitrification denitrification may be performed in the latter stage of the adjusting step, but aeration and nitrification denitrification here are not always necessary.

In order to solve the above-mentioned other problems, the present invention provides two or more types of wastewater treatment devices characterized by having the following (a) to (h). (A) Adjustment tank for homogenizing sewage containing rich SS such as septic tank sludge, household wastewater sludge, (b) coagulation processing tank for coagulating the effluent from the adjustment tank, (c) the coagulation processing A dewatering device that dewaters the aggregated slurry from the tank. (D) a storage tank for storing the dehydrated filtrate from the dehydrator, (e) the raw urine and the stored water in the storage tank under the condition that the stored water amount> the raw urine amount, and they are distributed in a predetermined proportion Is the amount
Biological treatment equipment for biological denitrification and dephosphorization treatment,
(F) a solid-liquid separator that separates the activated sludge slurry from the biological treatment device into activated sludge and treated water,
(G) an advanced treatment device for further treating the treated water from the solid-liquid separation device, (h) a water channel sequentially connecting (a) to (g), and excess activated sludge from the solid-liquid separation device. Transfer means for transferring to the adjustment tank of (a) and / or the aggregation tank of (b).

Further, in the above treatment apparatus, a concentrating / separating device is provided after the coagulation treatment tank of (b), the coagulated slurry from the coagulation treatment tank is separated into concentrated sludge and separated water, and the condensed sludge is dehydrated. An apparatus and a storage tank for storing the dehydrated filtrate and the separated water may be used. Further, a membrane separation device may be used as the solid-liquid separation device, and the membrane may be immersed in the liquid of the biological treatment step, or may be provided after the biological treatment step.

[0009]

[Function] Although the BOD, TN, and T-P of the septic tank sludge largely change due to a large change in the SS concentration, the dissolved components of the septic tank sludge (BOD, T-N in the filtrate,
(TP, etc.) does not change significantly even if the SS concentration changes.
Therefore, if a coagulant is added to the septic tank sludge in advance and SS is separated using a dehydrator or the like, a relatively stable treatment can be performed. However, aeration type and septic type septic tanks,
Alternatively, since the quality of the septic tank sludge is different between the small septic tank and the large septic tank, it is necessary to appropriately select and inject a coagulant that matches the properties of the incoming septic tank sludge, which is a major practical problem. It was

In the present invention, the septic tank sludge is received in the tank having a retention time of about 3 days or more and is stored and stirred, so that the septic tank sludge can be homogenized. It also reduces and facilitates SS removal by dehydration. Biological dephosphorization has an anaerobic tank at the inflow end of raw water into which sewage and return sludge flow in the activated sludge treatment process.
It releases phosphorus from the activated sludge under anaerobic conditions and also absorbs the BOD component to add phosphorus accumulation ability to the activated sludge to biologically remove phosphorus from the liquid. BOD / P ratio (kg / kg) = 25-30 or more is desirable for the target wastewater for biological dephosphorization, and in wastewater from which BOD components absorbed by activated sludge have been removed by preliminary aeration, phosphorus accumulation capacity is added to activated sludge. Can not do it.

Therefore, 30 m ³ of wastewater (aeration septic tank sludge BOD / P = 10) having a reduced BOD / P ratio is converted into human waste (B
OD / P = 32) BOD of the mixed solution by mixing with 10 m ³
When the / P ratio is reduced to about 16, the biological dephosphorization treatment, which could be achieved by the human waste alone treatment, cannot be performed by the mixed treatment. Therefore, when the present invention is carried out, phosphorus is removed by a coagulation treatment to increase the BOD / P ratio, and then septic tank sludge is mixed with urine.

The biological denitrification is to denitrify ammonia by nitrifying it and then adding BOD components of raw water or other organic substances such as methanol. Even in the case of biological denitrification, if the BOD is reduced by the preliminary aeration, the denitrification may be completed by increasing the amount of methanol added accordingly. Ammonia, which is the main component of the alkalinity of domestic wastewater, has an optimum pH (p) in the coagulation treatment with an iron-based or aluminum-based acidic inorganic coagulant.
It becomes an interfering substance when adjusting to the H4.5-6.0) range.
Therefore, in the present invention, the excess sludge generated in the activated sludge treatment step is mixed.

[0013]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Example 1 FIG. 1 is a process chart showing an embodiment of the present invention. In FIG. 1, the septic tank sludge 1 is passed through a water receiving tank 2 to remove coarse solids in the septic tank sludge 1 by a contaminant removing device 3 such as a screen, and after being discharged as a sieve residue 4,
Homogenized in the adjusting tank 5, and in the aggregating tanks 6 and 7, an iron-based aggregating agent (ferric chloride, polyiron, etc.), an aluminum-based (sulfuric acid band, pack, etc.) inorganic aggregating agent 8, polymer (organic polymer) Coagulant) 9 and then dehydrated cake 1 with a dehydrator 10 such as a belt press dehydrator or a multiple disc dehydrator.
1 and dehydrated filtrate 12 are separated. The dehydrated filtrate 12 is stored in a dehydrated filtrate storage tank (storage process) 13.

As the polymer, a cation polymer, an anion polymer, a combination of a cation polymer and an anion polymer, an amphoteric polymer and the like may be appropriately selected by an aggregation test. As an example, first, as the cationic polymer, an acid salt of N, N'-dimethylaminoalkyl acrylate or methacrylate, an acid salt of vinylbenzyltrimethylammonium, an acid salt of a cation-modified acrylamide, vinylpyridine and a substituted derivative thereof, These include homopolymers and copolymers of cationic monomers such as acrylic amine and its substituted derivatives. Further, copolymers of the above-mentioned cationic monomers with acrylamide, acrylonitrile, nonionic monomers such as acrylic acid alkyl esters, polyvinyl imidazoline acid salts, chitosan acid salts, starch cationized products, etc. Can also be used.

As the anionic polymer, acrylic acid, methacrylic acid and alkali metal salts thereof, sulfomethylated acrylamide and alkali metal salts thereof, vinylbenzene sulfonic acid, styrene sulfonic acid and alkali metal salts thereof, vinyl sulfonic acid and alkali thereof. A homopolymer or copolymer of an anionic monomer such as a metal salt or maleic anhydride is used.
In addition, the anionic monomer and acrylamide as described above,
Copolymers with nonionic monomers such as acrylonitrile and alkyl acrylate, sodium alginate, and anion-modified chitin can also be used. Depending on the case, PA may be used together with these organic polymer coagulants.
Inorganic flocculants such as C, sulfuric acid band, ferric chloride, ferrous sulfate, or lime may be used.

The amphoteric polymer is not particularly limited, and one composed of a copolymer containing a cationic monomer, an anionic monomer and optionally a nonionic monomer in one molecule is usually used. To be As examples of the cationic monomer, the anionic monomer and the nonionic monomer, each of the monomers exemplified in the above description of the cationic polymer and the anionic polymer can be used.

Since the septic tank sludge 1 contains a large amount of oil, it is advisable to attach an oil / water separation function, for example, a flotation / separation device, to the water receiving tank 2 in order to perform the treatment smoothly. Further, for the homogenization in the adjusting tank 5, a known stirring method, for example, air stirring, mechanical stirring, water stream stirring or the like can be used. In addition to the dehydrated filtrate 12, the dewatered filtrate storage tank 13 also receives miscellaneous wastewater 35 generated in the facility, such as deodorizing drainage, floor cleaning drainage, and dehydrator cleaning drainage.

The amount of gray water 35 cannot be generally stated depending on the scale of the treatment facility, the type of deodorizing device, the pump, and the dehydrator, but the smaller the scale of the treatment facility, the greater the ratio to the treatment septic tank sludge and live urine. Become. This is because the required amount of water is fixed to some extent regardless of the size of the facility. In addition, for example, a large amount of water is used to wash the filter cloth in a belt press type dewatering machine. It may be inflowed. In such a case, the amount of septic tank sludge dewatering filtrate and gray water is much larger than the amount of raw urine. The inflow of raw urine and stored water depends on the amount of water used in such ancillary equipment and the ratio of live urine and septic tank sludge to be carried in.
The ratio is 1: 1.2 to 1:20, preferably 1: 2 to 1:20.

The number of days that the septic tank sludge 1 of the water receiving tank 2 and the adjusting tank 5 stays is 1 to 2 with respect to the maximum amount of the septic tank sludge carried in, respectively.
Days, 3-5 days are desirable. The human waste 14 is stored in a human urine storage tank 18 after the coarse solids in the human waste 14 are removed by a contaminant removing device 16 such as a screen via the water receiving tank 15 and discharged as a sieve residue 17. The stored water 12 ′ and the depleted urine 19 flow into the anaerobic tank 21 under anaerobic conditions together with the returned sludge 20. Since phosphorus is released from the activated sludge in the anaerobic tank 21, the phosphorus concentration in the liquid rises, but the BOD substances in the stored water 12 'and the residual waste urine 19 are absorbed by the activated sludge, so the BOD in the anaerobic tank 21 is absorbed. The concentration decreases.

The activated sludge mixed solution in the anaerobic tank 21 then flows into the first denitrification tank 23 under anaerobic conditions together with the circulating nitrification solution 22, and the nitric acid in the circulating nitrification solution 22 is reduced and decomposed into nitrogen gas (denitrification). ) Will be done. B absorbed by activated sludge in anaerobic tank 21
OD substances are considered as reducing agents for denitrification. In the first denitrification tank 23, a part of phosphorus in the liquid is absorbed by the activated sludge by the energy generated by the denitrification action. The activated sludge mixed solution in the first denitrification tank 23 is then introduced into the nitrification tank 24 under aerobic conditions, the ammonia in the solution is oxidized to nitric acid, and the phosphorus remaining in the first denitrification tank 23 becomes activated sludge. After being absorbed, most of it is circulated to the first denitrification tank 23, and the rest flows into the second denitrification tank 25 under anaerobic conditions, and after nitric acid is denitrified, it is under aerobic conditions. It is introduced into the re-aeration tank 26.
An organic substance such as methanol may be added to the second denitrification tank 25 as a reducing agent for denitrification.

The activated sludge mixed liquid in the re-aeration tank 26 is subjected to solid-liquid separation by the membrane separation device 27 immersed in the tank, and the separated liquid 28 is introduced into the advanced treatment step 29. The membrane can be installed in a tank other than the re-aeration tank 26. For example, when a membrane is installed in the nitrification tank 24, the activated sludge mixed solution concentrated in the nitrification tank 24 is circulated to the first denitrification tank and also flows into the second denitrification tank, so that the amount of the returned sludge 20 is reduced. At least the MLSS concentration of the entire activated sludge treatment process can be increased. However, since the NOx-N remains in the membrane separated water 28, it is necessary to treat the separated water 28. In this way, the quality of the separated water 28,
If the treatment is appropriately selected, the membrane 27 is the activated sludge treatment step 32.
It can be installed in any of the tanks.

Solid-liquid separation of the activated sludge mixed liquid includes membrane separation,
Known solid-liquid separation devices such as a precipitation tank and a centrifuge can be used. A part of the activated sludge concentrated in the re-aeration tank 26 is returned to the anaerobic tank 21, and the rest is the excess sludge 31 in the adjusting tank 5.
Be transferred to. The effluent of the advanced treatment process 29 is treated water 30.
Released as. The advanced treatment step 29 may use advanced treatment methods such as activated carbon treatment, ozone treatment, coagulation treatment, and ultrafiltration membrane alone or in combination.

When the BOD source of the septic tank sludge 1 is reduced in the adjusting tank 5, the BOD / P of the septic tank sludge in the adjusting tank 5 is lowered, and the biological dephosphorization cannot be performed as described above. Also, when the polymer 9 is added to cause coagulation separation, fine SS components that are the BOD source of the septic tank sludge are coagulated and removed, but phosphorus is not removed, so that BOD / P is lowered. When such a dewatered filtrate 12 of septic tank sludge flows into the activated sludge treatment step 32, for example, the removed waste urine 19 which can be sufficiently dephosphorized by itself, the BOD / of the entire inflow water (excluded waste urine 19 + reserved water 12 ') P is lowered and biological dephosphorization cannot be performed.

The addition of the inorganic coagulant 8 in the coagulation tank 6 reduces the phosphorus concentration in the dehydrated filtrate 12 by coagulating and separating phosphorus in addition to conditioning the sludge for dehydration, and Since the BOD / P of the depleted urine 19 + retained water 12 ') can be kept high, biological dephosphorization becomes possible. The amount of the inorganic flocculant 8 to be added must be determined from the amount of sludge conditioning required, but if this amount is added, the dehydrated filtrate 12
The phosphorus concentration in the inside can be reduced to about 1 or less.

In the biological dephosphorization method for human wastewater, the dephosphorization function is impaired when the concentration of inorganic salts with chloride as an index increases (Japanese Patent Publication No. 3-8840). It has also been found that resistance to salt concentration causes resistance. The inventors of the present invention have proposed a conventional treatment method for septic tank sludge and human waste (Japanese Patent Publication No. 62-44999).
), An anaerobic tank was installed to add a biological dephosphorization function to the raw water inflow end of the activated sludge treatment.
A dephosphorization test was performed. As a result, denitrification was performed well, but dephosphorization was unstable.

Experimental examination of this result revealed that in the conventional method (Japanese Patent Publication No. 62-44999), human waste having a high salt concentration (about 3000 mg / chlorine ion).
(1 liter) was stably injected, whereas the dewatered separated water of septic tank sludge with a low salt concentration (about 200 mg / l as chlorine ion) was injected only during the day, so the anaerobic tank It was found that the cause was the large daily fluctuation. In biological dephosphorization treatment, once the balance is lost and the treatment is deteriorated, it takes a long time to recover. Since the chlorine ion concentration has stable physical properties and correlates with the concentration of pollutant components in human waste and septic tank sludge, it is used as an index of the density of those properties.

In the present invention, the number of days of inflow of the dehydrated filtrate storage tank 13 (dehydrated filtrate 12, miscellaneous wastewater 35) is at least 2
More than a day, the volume of the human waste storage tank 18 is set to be twice the maximum daily amount of human urine 14 to be carried in, and the stored water 12 ′ and the residual waste urine 1
By continuously injecting a fixed amount of 9 into the anaerobic tank 21, it is possible to suppress daily fluctuation and weekly fluctuation of the salt concentration in the anaerobic tank 21, and to perform stable dephosphorization.

In FIG. 3, when the dehydrated filtrate 12 and the miscellaneous waste water 35 are directly transferred to the human waste storage tank 18 without passing through the dehydrated filtrate storage tank 13, the dehydrated filtrate 12 and the miscellaneous waste water are sent to the human waste storage tank 18. The total inflow of 35 (chlorine ion concentration 111 mg / liter) is approximately ± 30%, and the inflow of human urine is plus or minus 30% (chlorine ion concentration 3000 mg / liter).
The change in the chlorine ion concentration in the human waste storage tank 18 is shown for each of the changes. Saturday and Sunday night soil 1
4. Since the work such as carrying in and dewatering of the septic tank sludge 1 is stopped, the inflow amount of the human waste storage tank 18 is set to zero.

FIG. 3 is based on the assumption that the amount accumulated in the human urine storage tank 18 per day was completely processed by the next day, and the storage tank was emptied on that day. In fact, the human waste storage tank 18
In this case, since the operation is such that the urine 19 always remains, the fluctuation pattern is different from that of FIG. 3, but the tendency is not changed. Biological dephosphorization cannot be carried out under such a condition that the chloride ion concentration of the inflowing liquid increases (changes) from several 100 mg / liter to about twice.

In the present invention, the fluctuations in the amount of the human waste 14 and the stored water 12 'can be adjusted in the respective storage tanks 13 and 18, so that the human waste 14 and the stored water 12' are separately stored in the anaerobic tank 21 for a long period of time. It can be injected quantitatively. Therefore, the human waste 14 and the stored water 12 'flowing into the anaerobic tank 21
The chlorine ion concentration of the mixture of No. 1 does not change as shown in the pattern of FIG.

In the conventional human waste treatment system, human waste storage tank 1
Although a fixed amount is continuously added from 8, the stored water 12 'hardly flows into the treatment device at the end (Saturday, Sunday). This is because in the conventional human waste treatment method, the capacity of the dehydrated filtrate storage tank 13 is only one day, and the stored water 12 'transfer pump is operated ON-OFF by the level meter of the dehydrated filtrate storage tank 13. As described above, the dehydration work is stopped on weekends and days, so that the dehydrated filtrate 12 is not generated, and the amount of miscellaneous drainage 35 is extremely reduced. As a result, the chlorine ion concentration in the anaerobic tank 21 fluctuates as shown in FIG.

FIG. 4 is a schematic diagram, and actually has a variation pattern like a SIN curve, but since the effect on biological dephosphorization occurs in the same manner as in FIG. 4, biological dephosphorization is performed under such conditions. You can't do phosphorus. As a result, the dehydrated filtrate storage tank 13 retains the stored water 12 'even on weekends.
It was thought that the inflow water (dehydrated filtrate 12, miscellaneous wastewater 35) in the dehydrated filtrate storage tank 13 must be retained for at least 2 days or more so that the water can be transferred.

In FIG. 4, the chlorine ion concentration of the stored water 12 (dehydrated filtrate generation amount 210 m ³ / week, sewage generation amount 148 m ³ / week) is 111 mg / liter, and human waste (10 K liters / day) is chlorine. Ion concentration is 3000 mg / liter, chlorine ion concentration of returned sludge (63 m ³ / day) is 56
This is when 3 mg / liter is used. Surplus sludge 3
Since 1 has a nitrification function, introduction of this excess sludge 31 into the adjusting tank 5 promotes nitrification (reduction of alkalinity) of ammonia in the septic tank sludge, so that the pH is effectively adjusted in the coagulation step 7. It can be easily controlled to 4.5 to 5.5 which can perform various sludge conditioning. Further, in the adjusting tank 5, the air volume is adjusted to continuously control the DO to 0.0 to 1.0 mg / liter,
Alternatively, denitrification can be further performed by performing intermittent aeration.

In the biological dephosphorization, the biological dephosphorization function is temporarily unstable due to an unexpected trouble, and phosphorus may remain in the permeate 28. In order to prevent this, any tank of the activated sludge treatment step 32 may be used, but preferably, a dephosphorization coagulant (iron-based or aluminum-based inorganic compound) is injected immediately before the solid-liquid separation step 27 of the re-aeration tank 26. Equipment (not shown) may be provided.

Embodiment 2 Next, another embodiment of the present invention will be described with reference to FIG. FIG. 2 is a process drawing showing another embodiment of the present invention. In FIG. 2, the septic tank sludge 1 is passed through the water receiving tank 2 to remove coarse solids in the septic tank sludge 1 by a contaminant removing device 3 such as a screen, and is discharged as sieve residue 4 and then in the adjusting tank 5. Homogenized, iron-based coagulant (ferric chloride, polyiron, etc.), aluminum-based (sulfuric acid band, pack, etc.) inorganic coagulant 8 or polymer (organic polymer coagulant) 9 in coagulation tanks 6 and 7 After being conditioned in step 3, it is concentrated in the concentration step 33 and separated into concentrated sludge 35 and separated water 34. The concentrated sludge 35 is dehydrated with the dehydrated cake 11 by a dehydrator 10 such as a belt press dehydrator or a multiple disc dehydrator. The filtrate 12 is separated. The dehydrated filtrate 12 is the separated water 34 in the concentration step 33.
It is stored together with the dehydrated filtrate storage tank (storage step) 13.

In the concentration step 33, a known concentration device such as a precipitation type concentration tank, a screen, and a granulation concentration can be used. The sludge 35 may be dehydrated by further adding an inorganic coagulant 8 or a polymer (organic polymer coagulant) 9. It is not necessary to separately provide the concentrating step 33 as long as it has a device structure and a stirring function added so that the coagulated sludge can be granulated and concentrated and separated in the coagulation tank 7. When such a device is provided, the separated water 34 can be introduced directly from the flocculation tank 7 into the dehydrated filtrate storage tank 13. As described in Example 1, a polymer may be appropriately selected from a cationic polymer, an anionic polymer, a combination of a cationic polymer and an anionic polymer, an amphoteric polymer, etc. by an aggregation test.

The septic tank sludge containing the excess sludge 31 having a high phosphorus content due to biological dephosphorization releases phosphorus when placed in an anaerobic thickening tank and deteriorates the separated water 34 and the stored water 12 '. Thus, the amount of phosphorus released in the concentration tank can be prevented by adding the inorganic coagulant in advance. However, it is desirable that the concentration time is short in order to prevent anaerobic progression. When the concentration tank is used in the concentration step, the concentration sludge becomes anaerobic and the denitrification phenomenon causes the sludge to float, which may hinder the concentration. NO by doing
Since x ⁻ is removed, it is possible to prevent the sludge from floating in the concentration tank.

Example 3 Next, an example in which sewage was treated according to the process diagram of FIG. 1 described in Example 1 will be described. The implementation conditions are shown below. (Hereinafter abbreviated as mixed sludge) waste water treatment amount of septic tank sludge and living wastewater sludge * -1: 15kl / day human waste: 10kl / day gray water: 2m ³ / day dehydration filtrate: 18m ³ / day Note) * - 1 Domestic miscellaneous wastewater sludge contamination rate 10-20%

Tank volume, mixed sludge water receiving tank: 15 m ³ adjusting tank: 60 m ³ night soil water receiving tank: 10 m ³ night soil storage tank: 20 m ³ dehydrated filtrate storage tank: 60 m ³ biological treatment device anaerobic tank: 8 m ³ first denitrification tank : 64m ³ Nitrification tank: 60m ³ 2nd denitrification tank: 20m ³ Re-exposure tank: 20m ³ Activated carbon adsorption tower: 6m ³ dehydrator, belt press Filter cloth width: 1.0m (with concentration mechanism, reuse of cleaning drainage circulation) )

Solid-Liquid Separation Step Membrane Separation Device An immersion type flat membrane device was used in which the membrane separation device was immersed in an aeration tank and the membrane permeated water side was sucked by a pump. Membrane area: 64 m ² Effective filtration pressure: −2 to −4 mAq Permeation flux: 0.5 to 0.6 m / day Liquid temperature: 25 to 35 ° C.

Amount of coagulant added Ferric chloride 1000 mg
/ Liter or sulfuric acid band 2000 mg / liter (as aluminum sulfate 18-hydrate) Amphoteric polymer (Ebara Infilco Co., Ltd., Ebagrose B-034: acrylamide, acrylic ester type): 1.5% vs. dry solids Return sludge amount: 90 m ³ / day Circulating nitrification liquid amount: 900 m ³ / day Aeration tank MLSS: 12000 mg / liter The results of Example 3 are shown in Table 1. Although not shown in Table 1, the T-P of the activated carbon-treated water was 0.5 mg / liter or less during the period when 100 mg / liter of ferric chloride was added to the re-aeration tank.

[0042]

[Table 1] Unit: mg / liter except for pH Note 1) The values of human urine and mixed sludge are those filtered through a screen. Note 2) The mean value for night soil and the fluctuation range for mixed sludge and activated carbon treated water.

Embodiment 4 Next, one embodiment of the present invention will be described based on the process diagram of FIG. 2 explained in Embodiment 2. (Hereinafter abbreviated as mixed sludge) waste water treatment amount of septic tank sludge and living wastewater sludge * -1: 30kl / day human waste: 10kl / day gray water: 164m ³ / day dehydration filtrate: 36m ³ / day Note) * - 1 Domestic miscellaneous wastewater sludge contamination rate 10-20%

Tank volume, mixed sludge water receiving tank: 30 m ³ adjusting tank: 110 m ³ concentrating tank 33: diameter 4.0 m (cylindrical type) effective water depth 3.5 m urine receiving tank: 10 m ³ night urine storage tank: 20 m ³ dehydrated filtrate Storage tank: 600m ³

Biological treatment device, anaerobic tank: 20 m ³ first denitrification tank: 80 m ³ nitrification tank: 70 m ³ second denitrification tank: 40 m ³ re-exposure tank: 20 m ³ activated carbon adsorption tower: 6 m ³ dehydrator, belt press filter Width of cloth: 2.0m (without concentration mechanism, without reuse of cleaning drainage circulation)

Solid-Liquid Separation Step Sedimentation tank: 6 m Flocculant addition amount Ferric chloride: 1000 mg / liter or sulfuric acid band: 2000 mg / liter (as aluminum sulfate 18-hydrate) Amphoteric polymer (Kurita Industry Co., Ltd., CLIVEST: Acrylic acid-acrylic acid ester-acrylamide system): 1.5% vs. dry solids Return sludge amount: 210 m ³ / day Circulating nitrification liquid amount: 1500 m ³ / day Aeration tank MLSS: 6100 mg / liter Table 4 shows the results of Example 4. 2 shows.

[0047]

[Table 2] Unit: mg / liter except for pH Note 1) The values of mixed sludge are those filtered through a screen. Note 2) Mixed sludge and activated carbon treated water show fluctuation range.

[0048]

The following effects can be obtained by the processing method of the present invention. (1) Since the properties of the septic tank sludge are homogenized by stirring and mixing in the adjusting tank, and further stabilized by the addition of an inorganic coagulant,
The polymer injection (measurement) work in the coagulation tank 7 becomes easy,
In addition, since the activated sludge treatment is performed together with urine after the septic tank sludge is dehydrated, stable denitrification and dephosphorization treatment can be performed regardless of changes in the characteristics of the septic tank sludge. (2) Since the human waste and the dehydrated filtrate can be continuously injected individually into the activated sludge treatment step, fluctuations in salt concentration in the anaerobic tank are eliminated, and stable biological dephosphorization treatment can be performed.

(3) Since the inorganic coagulant is added directly to the septic tank sludge to perform coagulation, phosphorus can be removed in the sludge treatment step. Therefore, BOD / P of the influent of the activated sludge treatment process
Since the ratio becomes large, biological dephosphorization can be performed stably. As a result, nitrogen, phosphorus, C
It is possible to obtain highly purified treated water that does not contain OD and chromaticity components. Further, since the inorganic coagulant is added to the septic tank sludge, it is possible to prevent the release of phosphorus into the liquid even when the sludge is anaerobicized during sedimentation and concentration as a pretreatment for dehydration.

(4) Since it is not necessary to perform coagulation treatment of biologically treated water, hardly dehydrated coagulation sludge is generated. Therefore,
The sludge load on the dehydrator can be reduced (the dehydrator can be reduced in size, and the amount of chemicals injected can be reduced), and the water content of the dehydrated cake can be reduced. (5) Since the nitrification (reduction of alkalinity) and denitrification of ammonia in the septic tank sludge can be performed and denitrification can be performed in the adjusting tank by introducing the excess sludge having nitrification and denitrification into the adjusting tank, the pH in the coagulation step 6 Adjustment can be easily performed.

[Brief description of drawings]

FIG. 1 is a process drawing showing an embodiment of the present invention.

FIG. 2 is a process drawing showing another embodiment of the present invention.

FIG. 3 is a graph showing the inflow amount of human waste storage tank and the Cl ⁻ concentration of stored liquid.

FIG. 4 is a graph showing a conventional anaerobic tank inflow amount and mixed solution Cl ⁻ concentration.

[Explanation of symbols]

1: Septic tank sludge, 2: Water receiving tank, 3: Contaminant removal device,
4: sieve residue, 5: adjusting tank, 6, 7: coagulating tank, 8: inorganic coagulant, 9: polymer, 10: dehydrator, 11: dehydrated cake,
12: Dehydrated filtrate, 13: Storage tank, 14: Human waste, 15: Water receiving tank, 16: Contaminant removing device, 17: Sieve residue, 18: Human waste storage tank, 19: Decontamination urine, 20: Return sludge, 21 : Anaerobic tank, 22: Circulating nitrification liquid, 23: First denitrification tank, 24: Nitrification tank, 25: Second denitrification tank, 26: Re-exposure tank, 27: Solid-liquid separation step, 28: Separation liquid, 29: Advanced treatment process, 30: treated water, 31: excess sludge, 32: activated sludge treatment process, 3
3: Concentration process, 34: Separation water, 35: Concentrated sludge

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshiyuki Ichiki 7-3-1-710, Hikarigaoka, Nerima-ku, Tokyo (72) Kensuke Matsui 6-22-1-104, Takaishi, Aso-ku, Kawasaki-shi, Kanagawa 72) Inventor Shunji Sasaki 693-10 Kamizuruma, Sagamihara City, Kanagawa Prefecture (72) Inventor Kiyoji Izumi 17-5-533 Besshohonmachi, Takatsuki City, Osaka Prefecture (72) Kenichi Terakawa 3-3-2 Shinmatsudo, Matsudo City, Chiba Prefecture

Claims (6)

[Claims] 1. A method for treating two or more kinds of wastewater, which comprises the following steps (a) to (g): (A) an adjusting step of homogenizing sewage containing rich SS such as septic tank sludge and household wastewater sludge, (b) an aggregating step of adding an aggregating agent to the effluent from the adjusting step, and performing an aggregating treatment, (C) a dehydration storage step of dehydrating the agglomerated slurry flowing out from the aggregating treatment step and storing an obtained dehydrated filtrate, (d) raw urine and stored water of the dehydration storage step, wherein the stored water amount> raw urine A biological treatment step of biologically performing denitrification and dephosphorization treatment under the condition of quantity and a predetermined proportion thereof, (e) the activated sludge slurry from the biological treatment step. A solid-liquid separation step of performing solid-liquid separation into activated sludge and treated water, (f) transferring excess activated sludge in the solid-liquid separation step to the adjustment step of (a) and / or the aggregation treatment step of (b) (G) the treated water of the solid-liquid separation step, Advanced treatment step of treating the. 2. A method for treating two or more kinds of wastewater, which comprises the following steps (a) to (h): (A) an adjusting step of homogenizing sewage containing rich SS such as septic tank sludge and household wastewater sludge, (b) an aggregating step of adding an aggregating agent to the effluent from the adjusting step, and performing an aggregating treatment, (C) a concentration / separation step of separating the agglomerated slurry flowing out from the agglomeration treatment step into concentrated sludge and separated water,
(D) a dehydration storage step of dehydrating the concentrated sludge of the concentration separation step and storing the obtained dehydrated filtrate and the separated water;
(E) biologically denitrifying and dephosphorizing the raw urine and the water stored in the dehydration storage step under the condition that the amount of stored water> the amount of raw urine, and in such an amount that they have a predetermined proportional distribution. A biological treatment step of: (f) a solid-liquid separation step of performing solid-liquid separation of the activated sludge slurry from the biological treatment step into activated sludge and treated water; (g) excess activity in the solid-liquid separation step A transfer step of transferring sludge to the adjusting step of (a) and / or the coagulation processing step of (b), and (h) an advanced treatment step of further treating the treated water of the solid-liquid separation step. 3. The solid-liquid separation step is one in which a membrane is immersed in the liquid of the biological treatment step, or one in which a membrane separation device is provided after the biological treatment step. Two
The method for treating sewage described. 4. An apparatus for treating sewage of two or more types, which has the following (a) to (h): (A) Adjustment tank for homogenizing sewage containing rich SS such as septic tank sludge, household wastewater sludge, (b) coagulation processing tank for coagulating the effluent from the adjustment tank, (c) the coagulation processing A dewatering device that dewaters the aggregated slurry from the tank. (D) a storage tank for storing the dehydrated filtrate from the dehydrator, (e) the raw urine and the stored water in the storage tank under the condition that the stored water amount> the raw urine amount, and they are distributed in a predetermined proportion Is the amount
Biological treatment equipment for biological denitrification and dephosphorization treatment,
(F) a solid-liquid separator that separates the activated sludge slurry from the biological treatment device into activated sludge and treated water,
(G) an advanced treatment device for further treating the treated water from the solid-liquid separation device, (h) a water channel sequentially connecting (a) to (g), and excess activated sludge from the solid-liquid separation device. Transfer means for transferring to the adjustment tank of (a) and / or the aggregation tank of (b). 5. A treatment apparatus for two or more kinds of wastewater, which has the following (a) to (i): (A) Adjustment tank for homogenizing sewage containing rich SS such as septic tank sludge, household wastewater sludge, (b) coagulation processing tank for coagulating the effluent from the adjustment tank, (c) the coagulation processing A concentration / separation device that separates the aggregated slurry from the tank into concentrated sludge and separated water, and (d) a dehydrator that dehydrates the concentrated sludge from the concentration / separation device. (E) a storage tank that stores the dehydrated filtrate from the dehydrator and the separated water, and (f) raw urine and the stored water of the storage tank under the condition that the stored water amount> the raw urine amount, and A biological treatment device for biologically denitrifying and dephosphorizing, in an amount that makes a predetermined proportional distribution, (g)
A solid-liquid separation device for solid-liquid separating the activated sludge slurry from the biological treatment device into activated sludge and treated water, (h) an advanced treatment device for further treating the treated water from the solid-liquid separation device, ( i) The water channels connecting the above (a) to (h) in sequence, and the surplus activated sludge from the solid-liquid separation device are added to the (a)
A transfer means for transferring to the adjusting tank and / or the aggregating tank of (b) above. 6. The solid-liquid separation device is a membrane separation device, which is immersed in the liquid of the biological treatment device or provided at a subsequent stage of the biological treatment device. The sewage treatment apparatus described.