JP3533064B2 - Method and apparatus for treating night soil, kitchen waste and sludge - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to energy-saving treatment of sludge in an organic wastewater treatment facility, sludge such as septic tank sludge, human waste, and kitchen waste containing plant and animal residues, and non-hygienic treatment of human waste and septic tank sludge. Sanitary compost of screen residue is used as a solid fuel, human waste, kitchen waste, sludge treatment method and equipment.
It is about the table .

[0002]

2. Description of the Related Art Anaerobic digestion of human waste has hitherto been widely adopted as an energy-saving treatment method. However, denitrification and dephosphorization treatments are currently being carried out to prevent eutrophication in closed water areas. An anaerobic digestion treatment facility is not currently constructed at all because it does not require denitrification and decomposes BOD substances in urine. Most of the septic tank sludge is treated with human waste in a human waste treatment facility. Some of the garbage in the combustibles discharged as general waste is directly landfilled in the final disposal site, but most of it is incinerated in the refuse incinerator at present.

[0003]

The denitrification treatment of human waste treatment is the power consumption of the blower for nitrification of nitrogen content, a large amount of sludge generated in the treatment process, and the dehydration and drying of unsanitary sieve residue generated in the pretreatment. Since the power consumption such as the power consumption of the drive unit of the device related to incineration is large and accounts for about half of the total processing cost, the reduction of the cost was a pending issue for urine processing.

Human waste contains a large amount of impurities such as toilet paper, vinyl pieces, cloth pieces, etc. In order to prevent the blockage of the pump due to these impurities in the human waste treatment, a rotary screen is usually used in the pretreatment step. To remove these contaminants. Water content separated 10
% Of the sieve residue is extremely unsanitary because it is covered with the waste of human waste, so it is not effectively used and is dehydrated by a screw press and then incinerated.

[0005] Septic tank sludge has a problem in treatment due to a large change in SS concentration, and the combined oily septic tank sludge causes obstacles such as floating of sludge in a sedimentation tank during water treatment.

[0006] The kitchen waste in the general waste causes a change in the calorific value in the incineration process, and it is feared that the salt in the kitchen waste will generate dioxin. Although some garbage is collected separately and composted, it is not always done smoothly due to the burden of composting consumption and distribution of manufactured compost.

The anaerobic digestion treatment of garbage in general waste is
Although it has been experimentally studied as a powerful technique, it is the current situation that it has not been put to practical use so far because the equipment and operation cost of the digestion / desorption liquid treatment become high.

The present invention has been made in view of the above points, and eliminates the above problems and treats kitchen waste containing sludge in an organic wastewater treatment facility, sludge such as septic tank sludge, human waste, and animal and plant residues in an energy-saving manner. Another object of the present invention is to provide a method and a device for treating human waste, kitchen waste, and sludge, which sanitarily composts unsanitary sieve residue in septic tank sludge and converts it into solid fuel.

[0009]

In order to solve the above-mentioned problems, the invention according to claim 1 is characterized by treating human waste, kitchen waste and sludge through the following steps (a) to (f). It is in the method of treating human waste, kitchen waste and sludge. (A) a first pretreatment step for solid-liquid separation of human waste mixed with sludge, (b) without dehydrating the solid matter separated in the first pretreatment step
Anaerobic digestion process of anaerobic digestion, a second pretreatment step of fractionating remove combustibles from (c) garbage inclusions, the garbage inclusions combustible material is fractionated removed; (d) second preprocessing step A step of introducing into the anaerobic digestion step, (e) a dehydration step of dehydrating and separating the discharged liquid from the anaerobic digestion step into solid matter and separated water, (f) separated water from the first pretreatment step, A biological treatment process in which the separated water from the dehydration process is biologically oxidized and denitrified.

The invention described in claim 2 is the same as claim 1.
Human waste according to, garbage, in the processing method of sludge, the stain
After the coagulant is added to the mud, the mud and the first
It is characterized in that it is introduced into the pretreatment process .

The invention described in claim 3 is the same as claim 1.
Alternatively , in the method for treating night soil, kitchen waste, sludge described in 2 ,
The anaerobic digestion step includes an acid fermentation (solubilization) step and an acid generation step.
It is characterized by comprising a methane fermentation process subsequent to the fermentation process.

The invention according to claim 4 is the same as claim 1.
In the method for treating night soil, kitchen waste, and sludge according to any one of 1 to 3, the solid matter from the dehydration step is composted.
And the impurities in the compost are removed from the second pretreatment step.
It is characterized in that it is mixed with the combustible substances mentioned above to be used as fuel.

[0013]

Further, the invention according to claim 5 is the first pretreatment means for solid-liquid separation of mixed urine containing sludge, and the first pretreatment means.
And anaerobic digestion means for anaerobic digestion of the solids separated in the preprocessing means, and second pre-processing means for separating removal of combustibles from kitchen garbage inclusions, combustible material is fractionated removed in the second pre-processing unit Means for introducing a garbage-containing material into the anaerobic digesting means; dehydrating means for dehydrating and separating the discharged liquid from the anaerobic digesting means into solid matter and separated water; and separated water from the first pretreatment means, A biological treatment means for biologically oxidizing and denitrifying the separated water from the dehydrating means, and a treatment apparatus for human waste, kitchen waste, and sludge.

The invention according to claim 6 is the same as claim 5
In the apparatus for treating night soil, kitchen waste, sludge, the coagulant adding means for adding a coagulant to the sludge is provided, and the sludge is introduced into the first pretreatment means after the coagulant is added. It is characterized by being.

The invention described in claim 7 is the same as claim 5
Or in the human waste, kitchen waste, sludge treatment device according to 6 ,
The anaerobic digestion means comprises an acid fermentation (solubilization) means and a methane fermentation means following the acid fermentation means.

The invention described in claim 8 is the invention according to claim 5.
Or human waste according to any one of 7, garbage, the processor of sludge, compost solids from the dewatering means
And the impurities in the compost are removed from the second pretreatment step.
It is characterized in that it is mixed with the combustible substances mentioned above to be used as fuel.

[0018]

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to this embodiment example. FIG. 1 is a diagram showing an example of the flow of a method for treating night soil, kitchen waste, and sludge of the present invention. Night soil 1
Is a pretreatment step 2 in which a solid-liquid separation device such as a rotary screen is provided, and coarse solids in the human waste 1 are removed. Sieve residue (coarse solid matter) is anaerobically digested through a sieve residue / sludge pipe 3. Introduced in step 4.

The filtrate 14 from which impurities have been removed is stored in the storage tank 5.
Is introduced into the nitrification / denitrification step 6 through which the nitrogen content is biologically treated. In the nitrification and denitrification step 6, a conventional technique such as a circulating nitrification and denitrification method can be used. The denitrification treated water 7 is further introduced into the advanced treatment step 8 for highly treating COD, phosphorus and the like, and the treated water 9 is discharged. In the advanced treatment step 8, conventional techniques such as a coagulation sedimentation method and an activated carbon adsorption method can be used.

The septic tank sludge 10 and the surplus sludge 11 of the nitrification / denitrification step 6 are coagulated by the polymer (organic polymer coagulant) 13 injected into the mixing tank 12, and then the pretreatment step 2
The separated sludge is introduced into the anaerobic digestion process 4 via the sieve residue / sludge pipe 3. The filtrate 14 passes through the storage tank 5 and is treated in the same manner as the urine filtration.

The anaerobic digestion step 4 can utilize conventional methane fermentation techniques such as methane fermentation tank single digestion, two-phase digestion in which an acid fermentation tank and a methane fermentation tank are connected.

As the solid-liquid separation device in the pretreatment step 2, an energy-saving and simple device such as a rotary screen, a granulation concentrating tank, an inclined wedge wire screen, etc. is used as compared with a centrifugal separator. The injection amount of the polymer 13 is S
Although it is about 1.0% of S (suspended solid matter), it varies depending on the type of solid-liquid separation device and sludge properties, so it is necessary to grasp the appropriate amount by mistakenly changing the injection amount at the beginning of operation.
Depending on the properties of the septic tank sludge 10, it is possible to perform solid-liquid separation without adding the polymer 13. In the pretreatment step 2, sludge relating to organic wastewater treatment such as septic tank sludge, groundwater sludge of surplus sludge, and agricultural settlement wastewater sludge can be treated.

If the anaerobic digestion step 4 becomes unstable due to, for example, overload conditions, the screen residue / sludge will be
Although not shown, it can be introduced into the dehydration step 20 for dehydration treatment.

Although the urine 1 as the coagulated sludge 33 may be injected into the solid-liquid separation device in a mixed state, the urine 1 may be separately introduced with the injection time zones shifted.

The garbage-containing combustible material 15 is introduced into the anaerobic digestion step 4 after the garbage bag is crushed, and the combustible material 19 such as metal 18 and plastic is separated and removed in the pretreatment step 16 to increase the garbage content rate. To be done. Separation and removal of combustible material 19 such as metal 18 and plastic from the combustible material 15 containing garbage
The separation removal device, crusher, classifier, it is possible to use a conventional type such as a magnetic separator.

The liquid discharged from the anaerobic digestion step 4 is separated into a dehydrated separation liquid 21 and a dehydrated sludge 22 in the dehydration step 20, the dehydrated sludge 22 is manufactured into a compost 24 by a composting device 23, and a contaminant removing device 25 is further added. By this, the impurities 26 such as plastic in the compost are removed, and the product compost 27 is produced. Separated combustible material 19, foreign matter 26
Is introduced into the solid fuel producing device 28, and the solid fuel 29 is produced.

In the dehydration step 20, since it is necessary to obtain dehydrated sludge 22 having a low water division ratio suitable for composting, the sludge dehydrated polymer 30 is injected at about 1.0% of SS, and centrifugal dehydration which is a conventional dehydrator is used. Water content of 80 with a dehydrator such as a machine, belt press, screw press, filter press
% Or less, preferably around 70%.
A rotating screen, a vibrating screen, or the like is recommended for the foreign matter removing device 25. As the solid fuel manufacturing apparatus 28, a high pressure compression molding machine which is becoming popular at present is recommended.

The biogas 30 'generated from the anaerobic digestion step 4 is stored in the gas tank 32 after the hydrogen sulfide in the gas is removed by the desulfurizer 31 and used for power generation.

Although not shown, the coagulated sludge 33 in the advanced treatment step 8 is preferably concentrated in a concentration tank or directly introduced into the dehydration step 20. This is because the coagulated sludge 33 is occupied by biologically inactive substances that hardly anaerobically digest. On the other hand, if the coagulated sludge 33 is introduced together with the septic tank sludge 10 into the pretreatment step 2 for concentration, the concentrating tank can be omitted, and therefore such a method can also be recommended.

FIG . 2 is a diagram showing an example of the flow of the method for treating night soil, garbage and sludge according to the present invention. Human waste 1 is a pretreatment step 2-1 in which a solid-liquid separation device such as a rotary screen is provided.
The coarse solid matter in the human waste 1 is removed, and the sieve residue (coarse solid matter) is introduced into the methane fermentation tank 4-2 of the anaerobic digestion step 4 via the sieve residue / sludge pipe 3. The filtrate 14-1 from which contaminants have been removed is processed through the storage tank 5 in the same manner as in the case of FIG.

The septic tank sludge 10 and the surplus sludge 11 from the nitrifying and denitrifying step 6 are coagulated by the polymer (organic polymer coagulant) 13 injected into the mixing tank 12, and then the pretreatment step 2-
Into the sludge, the separated sludge is introduced into the anaerobic digestion step 4 via the sieve residue / sludge pipe 3. The filtrate 14-2 is processed in the same manner as the filtrate 14-1 via the storage tank 5.
When the granulation concentration function is added to the mixing tank 12, the sludge can be concentrated and separated in the mixing tank 12, so that the pretreatment step 2-2 can be omitted.

In the pretreatment step 16, the garbage-containing combustible material 15 is disintegrated into trash bags, separated and removed into combustible materials 19 such as metal 18 and plastic to increase the garbage content rate, and then acid fermentation in the anaerobic digestion step. It is introduced into the tank 4-1. A circulation separation liquid (part of the dehydrated separation liquid 21) 21-1 for adjusting the SS concentration and supplying hot water is injected into the acid fermentation tank 4-1 and SS
The concentration is adjusted to around 15%. Since the water temperature of the acid fermentation tank 4-1 is recommended to be about 55 ° C, the circulation separation liquid 21-
1 is preferably heated to 55 ° C. or higher corresponding to the temperature of the inflow kitchen waste.

The acid fermentation tank 4-1 can promote the acid fermentation of the garbage and promote the subsequent methane fermentation of the methane fermentation tank 4-2. Further, in the methane fermentation tank 4-2, by adjusting the stirring strength, light weight contaminants such as plastics can be floated and sediment weight such as sediment can be settled and separated and removed during the garbage retention period. It is also possible to combine the function of 4-2 as a pretreatment step for impurities. Floating substances in the acid fermentation tank 4-1 are discharged regularly,
A dehydration process can be performed in the dehydration step 20.

[0035] in accordance with the water temperature of the methane fermentation tank 4-2 5
It can be about 5 ° C. Example 1 Next, with reference to FIG. 2, an example in which human waste, septic tank sludge, and separated kitchen waste are treated will be described. Treatment conditions Litter volume 10 m ³ / day Septic tank sludge amount 10 m ³ / day Excess sludge amount 6.5 m ³ / day Sorted kitchen waste amount 10 t / day Pretreatment process Rotary screen Opening 0.7 mm Cationic polymer injection amount (for sludge) vs. SS Ratio 1.0% Filtrate treatment equipment Biological treatment process Nitrification circulation method Advanced treatment process Coagulation treatment with ferric chloride and activated carbon treatment Sieve residue / separated sludge total amount 2.1 m ³ / day Sieve residue / sludge mixed concentration 6- 12% fractional garbage preconditioner selected crushing fractionator contaminants 30% (3t) garbage 70% (7t) acid fermentation tank (vertical screw agitator, sediment discharge pipe attached) effective volume 20 m ³ water temperature 55 ° C. circulating nitrification syneresis injection volume 12.1 m ³ / day methane fermentation tank (gas stirring facilities attached) effective volume 320 m ³ water temperature 55 ° C. dehydrator screw press dehydrator cationic polymer injection amount (for sludge Vs. SS 1.0% composting apparatus Badr formula fermenter impurity removing device vibrating sieve solid fuel apparatus compression molding machine generator gas engine generator

The processing result biogas generation amount 919m ³ / day (methane content 65%) Gas generation amount 1324Kwh / day compost production 2.8t / day (water content 30%) solid fuel production 5.8T / day acid Fermenter sediment discharge amount 20 L / 7 days Night soil, Filtrate solution treatment results of septic tank sludge are shown in FIG.

As described above, according to the present invention, a large amount of biogas can be generated, and it has been found that almost all the electric power of the entire treatment facility can be self-sufficient by the gas power generation. Contaminants of human waste and septic tank sludge are separated in a silent process 2
In Example 5, the product compost 27 and the contaminants 26 were distributed, but neither the product compost 27 nor the contaminants 26 had an unpleasant odor caused by urine, and the appearance was hygienic. As a result of mixing and combusting the combustible material 19 separated from the contaminated portion 26, a solid fuel having excellent ignitability and high calorie was produced.

[0038] In addition, raw sewage, septic tank sludge, excess sludge Figure 1
As a result of performing the treatment in the pretreatment step 2 of 1. and then performing the treatment under the same conditions as in Example 1, the same treatment result as in Example 1 was obtained.

[0039]

EFFECTS OF THE INVENTION (1) Since the screen residue of human waste can be treated without dehydration with a dehydrator such as a screw press, installation and operation management of the dehydrator are unnecessary.

(2) Since dirt and malodorous substances adhering to the sieve residue of human waste can be decomposed and removed in the anaerobic digestion step, compost or solid fuel can be made odorless and sanitary.

(3) The anaerobic digestion treatment method has been constructed as a main technique for treating human waste, but since it is not suitable for removing nitrogen and phosphorus that are densely impregnated in human waste, it is not constructed at all at present. It was In the present invention, since it is possible to denitrify and dephosphorize human waste sewage and obtain biogas energy for the treatment, it is possible to denitrify and dephosphorize human waste and sludge filtered water at a low treatment cost. it can.

(4) A sludge (hereinafter abbreviated as “sludge”) generated by human waste treatment by subjecting kitchen waste to methane fermentation can significantly increase the insufficient treatment energy.

(5) Since the amount of sludge and kitchen waste can be reduced by anaerobic digestion, the equipment cost and processing cost associated with the treatment of sludge and kitchen waste can be reduced.

(6) Digestion and desorption liquid, which is the biggest problem that kitchen methane fermentation has not been put to practical use economically, can be highly processed at a low processing cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow example of a method for treating human waste, kitchen waste, and sludge of the present invention.

FIG. 2 is a diagram showing an example of a flow of a method for treating night soil, kitchen waste, and sludge of the present invention.

FIG. 3 is a view showing the results of treating human waste and septic tank sludge with a filtrate according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiro Suzuki 11-1 Haneda Asahi-cho, Ota-ku, Tokyo Stock company Ebara Corporation (72) Inventor Hideo Aijima 11-1 Haneda-Asahi-cho, Ota-ku, Tokyo Shares (56) Reference JP-A-9-201599 (JP, A) JP-A-6-246298 (JP, A) JP-A-63-30388 (JP, A) JP-A-59-39395 ( JP, A) JP-A-6-39396 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/28-3/34 C02F 11/00-11/20 B09B 3 / 00

Claims (8)

(57) [Claims] 1. A method for treating human waste, kitchen waste, and sludge, which comprises treating human urine, kitchen waste and sludge through the following steps (a) to (f). (A) a first pretreatment step for solid-liquid separation of human waste mixed with sludge, (b) without dehydrating the solid matter separated in the first pretreatment step
Anaerobic digestion process of anaerobic digestion, a second pretreatment step of fractionating remove combustibles from (c) garbage inclusions, the garbage inclusions combustible material is fractionated removed; (d) second preprocessing step A step of introducing into the anaerobic digestion step, (e) a dehydration step of dehydrating and separating the discharged liquid from the anaerobic digestion step into solid matter and separated water, (f) separated water from the first pretreatment step, A biological treatment process in which the separated water from the dehydration process is biologically oxidized and denitrified. 2. The method for treating night soil, kitchen waste, and sludge according to claim 1, wherein the sludge is introduced into the first pretreatment step together with the night soil after adding a flocculant. 3. The anaerobic digestion step is acid fermentation (solubilization).
The method for treating human waste, kitchen waste, and sludge according to claim 1 or 2, comprising a step and a methane fermentation step subsequent to the acid fermentation step. 4. The solid matter from the dehydration step is composted.
To remove impurities in the compost from the second pretreatment step.
The method for treating night soil, kitchen waste, and sludge according to any one of claims 1 to 3, wherein the fuel is mixed with a fuel. 5. A first method for solid-liquid separation of human waste containing sludge.
Pretreatment means, anaerobic digestion means for anaerobically digesting the solid matter separated by the first pretreatment means without dehydration, second pretreatment means for separately removing combustible substances from the garbage content, 2 means for introducing into the anaerobic digestion means the waste-containing material from which the combustibles have been separated and removed by the pretreatment means, and dehydration means for dehydrating and separating the discharged liquid from the anaerobic digestion means into solid matter and separated water, And a biological treatment means for biologically oxidizing and denitrifying the separated water from the first pretreatment means and the separated water from the dehydration means. Treatment of human waste, kitchen waste, sludge apparatus. 6. provided coagulant adding means for adding a coagulant to the sludge, the sludge and features that it is so after the flocculant is added, is introduced into the first pre-processing unit The apparatus for treating night soil, kitchen waste, and sludge according to claim 5 . 7. The anaerobic digestion means is acid fermentation (solubilization).
7. The apparatus for treating night soil, kitchen waste, sludge according to claim 5 or 6 , comprising a means and a methane fermentation means subsequent to the acid fermentation means. 8. compost solids from the dewatering means
To remove impurities in the compost from the second pretreatment step.
The treatment apparatus for human waste, kitchen waste, sludge according to any one of claims 5 to 7 , which is used as a fuel by mixing with a combustible material.