JP2002307093A - Treatment method and apparatus for discharging high concentration organic wastewater to sewerage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method and apparatus, which can achieve the quality of treated water conforming to the effluent standard values for sewage treatment facilities with a low equipment cost and a small volume of drainage. SOLUTION: In this treatment method, high concentration organic waste water (a) is subjected to biochemical nitrification and denitrification treatment 1, the resultant activated sludge slurry is subjected to solid-liquid separation treatment 2, the resultant thickened sludge 9 is subjected to dehydration treatment 4 after adding a coagulant and a coagulant aid, and the resultant dehydrated and separated liquid 5 and the separated liquid 8 after the solid-liquid separation are mixed to be discharged to sewerage b. Secondary denitrification treatment may be added to the biological nitrification and denitrification treatment. When COD concentration is regulated in effluent standards for sewage, coagulating separation treatment may be additionally performed before discharging the separated liquid to sewerage, thereby phosphorous and COD in the final effluent can be removed. A membrane separation device or a filter cloth type solid-liquid separation device can be used for the above solid-liquid separation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment for discharging high-concentration organic wastewater into a sewerage system, and more particularly, to a high-concentration organic wastewater such as human waste, septic tank sludge, and rural settlement drainage sludge in a sewerage treatment facility. The present invention relates to a treatment method and an apparatus for treating activated sludge, which has been biochemically nitrified and denitrified, to a water quality that conforms to a wastewater treatment facility drainage standard value when draining the wastewater.

[0002]

2. Description of the Related Art As a main treatment technique for discharging conventional high-concentration organic wastewater to a sewage treatment facility, there are the following treatment methods. A method that removes contaminants from high-concentration organic wastewater with a screen, dilutes it, and drains it. A method in which high-concentration organic wastewater is subjected to direct dehydration treatment after removing contaminants with a screen, and the dehydrated separated liquid is diluted and drained. The high-concentration organic wastewater is biochemically nitrified and denitrified from the liquid from which contaminants have been removed with a screen. The treated activated sludge slurry is mechanically concentrated and separated by a concentrator, and the separated liquid is diluted and drained. method.

[0003] These conventional techniques have the following problems. (A) In the treatment method and, the dilution ratio for obtaining the water quality conforming to the wastewater standard value of the sewage treatment facility is 15 to 15.
It is 30 times as large, and the water load of the sewage treatment facility is large. In addition, sewerage charges will increase. (B) The method of mechanical concentration separation has a sludge recovery rate of 90%.
%, And it is difficult to obtain a separated liquid having a stable property. As a solution to this, there is a case where a conventional high-load denitrification treatment method or a membrane separation high-load denitrification treatment method, which is a conventional human waste treatment method, is also used in sewage discharge. Since both SS and BOD concentrations are generally 150 to 600 mg / L, the adoption of the conventional human waste treatment method results in excessive equipment and waste of equipment cost.

[0004]

DISCLOSURE OF THE INVENTION In view of the above prior art, the present invention provides a treatment method capable of obtaining a treated water quality that can comply with a wastewater standard value to a sewage treatment facility with inexpensive equipment costs and a small amount of wastewater. It is an object to provide a device.

[0005]

According to the present invention, a high-concentration organic wastewater is biochemically nitrified and denitrified, and the obtained activated sludge slurry is subjected to a solid-liquid separation treatment. And a dewatering treatment by adding a flocculant and a flocculation aid to the obtained concentrated sludge, and a treatment method characterized by mixing the obtained dewatered separated liquid and the separated liquid obtained by solid-liquid separation and discharging the mixed liquid to a sewer. It was done. In the treatment method, when the nitrogen concentration regulation is strict in the sewage discharge standard,
A secondary denitrification treatment can be added to the biochemical nitrification and denitrification treatment.If there is a phosphorus or COD concentration regulation in the sewage standards, it is further agglomerated before being discharged to the sewage. A separation treatment can be performed to remove phosphorus or COD in the effluent.

The present invention also provides a nitrification and denitrification apparatus for biochemically nitrifying and denitrifying high-concentration organic wastewater.
A solid-liquid separation device for performing a solid-liquid separation process on the activated sludge slurry obtained from the device, a coagulant to the obtained concentrated sludge, a sludge dewatering device for performing a dehydration process by adding a coagulation aid, and the solid-liquid separation device. A processing apparatus is characterized in that a flow path for mixing the obtained separated liquid and the dehydrated separated liquid and discharging the mixed liquid to a sewer is provided. In the above, the solid-liquid separation is performed using a membrane separation device or a filter cloth type solid-liquid separation device, and a separated liquid as a clear permeate and concentrated sludge can be obtained.

[0007]

Next, the present invention will be described in detail.
In the present invention, the solid-liquid separation device can be an ultrafiltration membrane separation device or a filter cloth type solid-liquid separation device depending on the treatment water quality required for the membrane separation device. As the sludge dewatering device, a belt press type dehydrator, a multiple disc type dehydrator, a centrifugal dehydrator, a filter press type dehydrator, etc. can be adopted, and an inorganic flocculant, a polymer flocculant as a sludge conditioning agent. Or both can be added. When the nitrogen concentration is less than 100 mg / L in the wastewater standard for sewage treatment facilities,
A nitrogen removal treatment can be performed by adding a secondary denitrification tank to the biochemical treatment equipment, and a denitrification accelerator can be added to the secondary denitrification tank. In addition, in the case where the concentration of phosphorus or the concentration of COD is regulated in the wastewater standard for the sewage treatment facility, a coagulation separation treatment can be performed in addition to the treatment method according to the present invention.

Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 is a schematic process diagram showing an example of the processing apparatus of the present invention. In FIG. 1, 1 is a biochemical nitrification / denitrification tank, 2
Is a solid-liquid separation device such as an ultrafiltration membrane separation device, 3 is a sludge storage tank, 4 is a sludge dewatering device, 5 is a dewatering separation liquid tank, 6 is a coagulation separation facility, and 7 is a mixing / discharging tank. In FIG. 1, high-concentration organic wastewater a such as night soil is sent to a biochemical nitrification / denitrification tank 1 where it is subjected to biochemical nitrification / denitrification, and the obtained activated sludge slurry is subjected to ultrafiltration membrane separation. The permeated liquid 8 and the concentrated sludge 9 are separated by a solid-liquid separation device 2 such as a device. The obtained permeated liquid 8 is subjected to removal of phosphorus and COD in the coagulation / separation equipment 6 as required according to the drainage standard value. If this treatment is not necessary, it is transferred directly to the mixing / discharging tank 7.

The concentrated sludge 9 separated into solid and liquid is supplied to the sludge storage tank 3.
And then sent to the sludge dewatering device 4 for dewatering. After the dehydrated separation liquid is stored in the dehydration separation liquid tank 5, the solid-liquid separation device 3
The phosphorus and COD are removed together with the permeate 8. If this treatment is not necessary, it is directly transferred to the mixing / discharging tank 7, diluted and mixed with the permeated liquid 8 of the solid-liquid separator, and discharged to the sewerage treatment facility b. In the coagulation / separation equipment 6, an inorganic coagulant, a polymer coagulant or both of them are added to the waste water while adjusting the pH to perform coagulation treatment in order to increase the treatment efficiency. As the coagulation / separation equipment 6, any one of a coagulation / sedimentation tank, a flotation separation tank, an ultrafiltration membrane, and a filter cloth type solid-liquid separation device can be used. In the sludge dewatering device 4, in order to increase the sludge dewatering efficiency and obtain a clear separated liquid, an inorganic flocculant, a polymer flocculant, or both of them can be added and refined.

[0010]

The present invention will be described below in more detail with reference to examples. Example 1 As the high-concentration organic wastewater, human waste and septic tank sludge having the concentrations shown in Table 1 were treated according to the present invention. Processing volume is 10
0 m ³ / day (including 20% human waste and 80% septic tank sludge).

[Table 1]

Table 2 shows the properties of the treated water according to the treatment method of the present invention. In Table 2, Cases 1 to 3 are as follows. Case 1: When a secondary denitrification tank and coagulation / separation equipment are not provided Case 2: When a secondary denitrification tank is provided after a biochemical nitrification / denitrification tank and no coagulation / separation equipment is provided Case 3: When both secondary denitrification tank and coagulation separation equipment are installed,

[Table 2]

[0012]

According to the present invention, the following effects can be obtained. The amount of treated wastewater is about twice the amount of organic wastewater such as human waste, so that the load on the sewage treatment facility can be reduced and the water charge can be reduced. It is an inexpensive treatment facility with no waste as equipment. Stable treatment water quality can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic process diagram showing an example of a processing apparatus of the present invention.

[Explanation of symbols]

1: Biochemical nitrification / denitrification tank 2: Solid-liquid separation device
3: sludge storage tank, 4: sludge dewatering device, 5: dehydration separation liquid tank, 6: coagulation separation equipment, 7: mixing / discharging tank, 8: permeate, 9: concentrated sludge, a: high-concentration organic wastewater, b: drainage

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C02F 11/14 C02F 11/14 A // C02F 1/00 1/00 LF term (reference) 4D006 GA02 HA93 MB02 PA01 PB08 PB15 PB24 PC62 4D015 BA19 BB05 CA02 CA03 CA18 DB01 DC02 EA02 EA32 FA15 FA17 FA26 4D040 BB02 BB25 BB33 BB52 BB73 4D059 AA03 BE08 BE16 BE38 BE55 BE56 CA28

Claims (5)

[Claims] 1. A high-concentration organic wastewater is biochemically nitrified and denitrified, the obtained activated sludge slurry is subjected to solid-liquid separation, and a coagulant and a coagulation aid are added to the obtained concentrated sludge. A dewatering treatment, and mixing the obtained dewatered separated liquid with the separated liquid obtained by solid-liquid separation and discharging the mixed liquid into a sewer. 2. The treatment method according to claim 1, wherein a secondary denitrification treatment is added to the biochemical nitrification / denitrification treatment. 3. The processing method according to claim 1, wherein a coagulation separation process is further performed before discharging into the sewer to remove phosphorus or COD in the discharged water. 4. A method for biochemical nitrification of high-concentration organic wastewater.
A solid-liquid separator for solid-liquid separation of activated sludge slurry obtained from a nitrification / denitrification processor for denitrification, and a sludge dewatering device for dehydration by adding a flocculant and a flocculation aid to the obtained concentrated sludge And a flow path for mixing the separated liquid obtained from the solid-liquid separation device with the dehydrated separated liquid and discharging the mixed liquid to the sewer. 5. The processing apparatus according to claim 4, wherein said solid-liquid separation device is a membrane separation device or a filter cloth type solid-liquid separation device.