JPS63158195A - Treatment of sewage - Google Patents

Abstract

PURPOSE:To treat sewage at low cost, by treating the sewage using powdery coke as a carrier. CONSTITUTION:A treatment tank 3 is packed with a carrier composed of powdery coke. Subsequently, raw sewage 1 is introduced into the treatment tank 3 by a raw water pump 2 and, at the same time, air is blown in the distribution cylinder 4 arranged in the treatment tank 3 from a blower 5. The carrier 6 in the treatment tank 3 is allowed to rise in the distribution cylinder 4 by air lift action and subsequently allowed to fall in the treatment tank 3 outside the distribution cylinder to be smoothly fluidized and recirculated. After the biological oxidation treatment, the carrier 6 is separated by the carrier separation part 7 provided to the upper part of the treatment tank 3 and treated water 8 is allowed to overflow from the separation part 7. By this method, sewage can be satisfactorily purified at low running cost.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for treating wastewater such as sewage, various industrial wastewater, and domestic water, and particularly relates to an improvement in a method for treating wastewater using a carrier to which microorganisms are attached. .

[Prior Art] As one of the sewage treatment methods, there is a fluidized bed treatment method in which a carrier is kept in a fluidized state in a treatment tank and the sewage supplied into the treatment tank is purified by the action of microorganisms attached to the carrier. It has been known. These fluidized bed sewage treatment methods include:
There are an aerobic fluidized bed treatment method and an anaerobic fluidized bed treatment method, which will be explained below.

In the aerobic fluidized bed treatment, as shown in FIG. 1, raw sewage l is introduced into a treatment tank 3 by a raw water pump 2.

At the same time, air is blown from the aeration blower 5 into the rectifier gJ4 arranged in the treatment tank 3, and after the carrier 6 in the treatment tank 3 is raised inside the rectifier cylinder 4 by the air lift action, The inside of the processing tank 3 is lowered to smoothly flow and circulate the carrier 6. Through these operations, the raw sewage is transferred to the treatment tank 3.
After being subjected to biological oxidation treatment by aerobic microorganisms attached and propagated on the carrier 6 which is kept in a fluid state within the tank, it overflows as treated water 8 from the carrier separator 7 at the upper part of the treatment tank 3.

This carrier separation section 7 functions to prevent the circulating carrier B from flowing out of the treatment tank 3 together with the treated water 8.

In the anaerobic fluidized bed treatment, as shown in FIG. In this method, raw wastewater is subjected to anaerobic biological treatment using a substance and then discharged as treated water 8. In this case, the flow of the carrier 6 is achieved by introducing a part of the treated water 8 as a circulating liquid 9 from the lower part of the treatment tank 3 using a circulation pump 10.

Incidentally, the carrier used in the fluidized bed sewage treatment method has conventionally been made of sand or activated carbon.

[Problems to be Solved by the Invention] However, conventional sewage treatment methods using sand or activated carbon as carriers have had the following problems.

(9) When activated carbon is used as a carrier, it is expensive due to its manufacturing raw materials and manufacturing technology, leading to an increase in wastewater treatment costs.

(2) When sand is used as a carrier, the price is not so much of an issue, but since the specific gravity is as high as 2.6, a large amount of energy is required to fluidize it, which causes an increase in wastewater treatment costs.

■Also, when sand is used as a carrier, when microorganisms adhere to the carrier and the apparent specific gravity becomes small, the carrier separation section at the top of the treatment tank cannot completely separate the sand from the treated water, resulting in sand being mixed with the treated water. may leak outside. In such a case,
The carrier is introduced into the sludge treatment process together with excess sludge, but since sand is nonflammable, even if it is incinerated, it remains as a residue and becomes unnecessary industrial waste.

The above-mentioned problems (1) and (2) are common not only to fluidized bed sewage treatment methods using biofouling carriers, but also to fixed bed sewage treatment methods.

The present invention was made to solve the above-mentioned conventional problems, and provides a method for treating wastewater using a low-cost carrier and at low running costs.

[Means for Solving the Problems] The present invention is a sewage treatment method for purifying sewage by the action of microorganisms attached to a carrier, which is characterized in that powdered coke is used as the carrier.

Coke generated in wet extinguishing equipment or coke, or coke pulverized into powder, etc. can be used.

[Function] However, since the powdered coke used as a carrier in the present invention has a specific surface area of, for example, 20 to 5011 L2/g, it is possible to attach a sufficient amount of microorganisms.1. Sewage can be effectively treated with microorganisms. In addition, powdered conics is significantly cheaper than activated carbon, and has a specific gravity of, for example, 1.
8 to 1.9, which is lower than that of sand, making it easy to fluidize when applied to fluidized bed sewage treatment. Furthermore, when powdered coke is applied to fluidized bed sewage treatment, when microorganisms adhere to the carrier and the apparent specific gravity becomes smaller, the carrier cannot be completely separated in the carrier separation section and the coke itself flows out together with the treated water. There are things to do. In this case, the effluent carrier is introduced into the sludge treatment process together with excess sludge, and undergoes treatments such as concentration, anaerobic digestion, clarification, and incineration, but the powdered coke used as the carrier acts as a solid fuel containing carbon. , it can self-combust during the incineration process, eliminating the need to consider cumbersome treatment as unnecessary industrial waste. Therefore, wastewater can be effectively purified using a low-cost carrier and at low running costs.

[Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2 described above.

Example 1 First, as shown in FIG. 1, a carrier made of powdered coke was filled into the treatment tank 3. Subsequently, raw sewage l was introduced into the treatment tank 3 by the raw water pump 2.

At the same time, a blower 5 is installed in the rectifier cylinder 4 arranged in the processing tank 3.
Air is blown into the treatment tank 3 to raise the carriers 6 inside the rectifying cylinder 4 by air lift action, and then lowering the inside of the treatment t'63 outside the rectifying cylinder 4 to smoothly flow and circulate the carriers G. I let it happen. Through these operations, the raw sewage is subjected to biological oxidation treatment by aerobic microorganisms attached and bred on the carrier 6 kept in a fluid state in the treatment tank 3, and then the carrier 6 is removed by the carrier separation section 7 at the upper part of the treatment tank 3. The treated water 8 was allowed to overflow from the separation section 7.

The following conditions were set for the above wastewater treatment.

Processing tank 3: Effective volume ff150 (flowing section volume i!25i,
Capacity of carrier separating section 25)), Diameter of carrier separating section 40011
% Diameter of flow section 200zi.

Rectifier cylinder 4; diameter 140zm, height 1000F! 1a.

Powdered coke as a carrier; components shown in Table 1 below recovered from the cyclone of coke dry extinguishing equipment, having a particle size distribution shown in Table 2 below, and a specific gravity of 1.8 to 1.9
, a specific surface area of 20 to 50 m2/g was used, and 5.0 m2/g was filled into the processing tank 3.

Comparative Example 1 Effective diameter of carrier: 0.11 m, uniformity coefficient: 1.8, specific gravity: 2
．． The same aerobic fluidized bed sewage treatment as in Example 1 was carried out except that No. 6 sand was used.

Thus, the amount of air from the aeration blower 5 required to fluidize the carrier in Example 1 and Comparative Example 1 was measured. As a result, in the case of powdered coke of Example 1, 8
/1n1 In the case of the sand of Comparative Example 1, it is 5(lj' / 1n
Therefore, it was confirmed that it was possible to fluidize the carrier with an amount of air about 1/6 compared to Comparative Example 1.

Table 1 Table 2 Example 2 First, as shown in FIG. 2, a carrier made of powdered coke was filled into the treatment tank 3. Next, the raw sewage l is introduced into the treatment tank 3 by the raw water pump 2, and at the same time, a part of the treated water 8 is introduced from the lower part of the treatment tank 3 by the circulation pump lO as the circulating liquid 9, and the carrier in the treatment tank 3 is 6 is made to flow, and the carrier 6
Raw sewage was subjected to anaerobic biological treatment using anaerobic microorganisms grown in adhesion, and treated water 8 was discharged from the upper part of treatment tank 3, and a portion was used as circulating fluid 9.

The following conditions were set for the above wastewater treatment.

Processing tank 3; effective capacity 28), diameter 20011%.

Height: 1000B.

Powdered coke as a carrier having the same properties as in Example 1 was filled into the treatment tank 3 in an amount of 11.0 μm.

Comparative Example 2 As a carrier, the effective diameter is 0.11jIJl, the uniformity coefficient is 1.8,
Anaerobic fluidized bed sewage treatment was carried out in the same manner as in Example 2, except that sand with a specific gravity of 2.6 was used.

Therefore, the circulating water ff1 (linear velocity) necessary to obtain a carrier expansion rate of 50% in Example 2 and Comparative Example 2 was investigated. As a result, in the case of the powdered coke of Example 2, 3.
8771/hr, 15.3 m/hr for sand of Comparative Example 2
r, and it was confirmed that it was possible to fluidize the carrier at a linear velocity of about 1/4 compared to Comparative Example 2.

Example 3 An urban sewage treatment experiment was conducted using the sewage treatment apparatus shown in FIG. 1 and the sewage treatment apparatus shown in FIG. 2. In the aerobic fluidized bed sewage treatment shown in Fig. 1, the treatment tank 3 was filled with 5.0 kg of powdered coke similar to that in Example 1, and the raw water having the properties shown in Table 3 below was flowed at 9300 ff/da. ' / is introduced into the processing tank 3, and the air amount is 8. ff/ff1in. In the anaerobic fluidized bed sewage treatment shown in FIG. ,i? The raw water with similar properties was introduced into the treatment tank 3 at fLQ 9 (D'/day), and the circulation flow rate was 2.0, ff/min.The results were as follows:
It is also listed in Table 3.

Table 3 As is clear from Table 3 above, it can be seen that by using powdered coke as a carrier, BOD% COD can be removed well in both aerobic fluidized bed sewage treatment and anaerobic fluidized bed sewage treatment. . Furthermore, it can be seen that excellent results can be obtained in nitrification treatment in aerobic fluidized bed wastewater treatment.

In addition, although the above-mentioned example explained the fluidized bed type sewage treatment, the same effect can be exhibited even if it is applied to the fixed bed type sewage treatment.

[Effects of the Invention] As detailed above, according to the present invention, a low-cost carrier,
Moreover, it is possible to provide a sewage treatment method that can purify sewage well at low running costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an aerobic fluidized bed type sewage treatment device, and FIG. 2 is a schematic diagram showing an anaerobic fluidized bed type sewage treatment device. l... Raw sewage, 2... Raw water pump, 3... Treatment tank, 4... Rectifier cylinder, 5... Aeration blower, 6...
Carrier, 7... Carrier separation section, 8... Treated water, 9...
Circulating water, lO...circulation pump. Applicant's agent Patent attorney Takehiko Suzue No. 1 Ref. 2

Claims (1)

[Claims] A sewage treatment method for purifying sewage by the action of microorganisms attached to a carrier, characterized in that powdered coke is used as the carrier.