JP6169907B2 - Coke oven wastewater treatment equipment, coke oven wastewater treatment method - Google Patents

Description

  The present invention relates to a coke oven wastewater treatment apparatus and a coke oven wastewater treatment method.

Conventionally, coke oven wastewater discharged from a coke oven is made to flow into wastewater treatment equipment and detoxified by activated sludge.
In general, coke oven effluent contains biotoxic components such as ammonia (NH ₄ ), cyanide (CN), thiocyan (SCN), and phenols derived from coke raw material coal. Therefore, when the coke oven wastewater is allowed to flow into the aeration tank, dilution is performed with dilution water to reduce the load.
For example, Patent Document 1 describes an activated sludge treatment method in which industrial water and seawater are flowed into an aeration tank as dilution water in a method in which raw water is introduced into an aeration tank and continuously treated with activated sludge.

JP 2005-46697 A

By the way, in the activated sludge treatment of coke oven wastewater, the treated water treated in the aeration tank is usually sent to the settling tank and separated into sludge and supernatant water, and the supernatant water is further removed from the turbidity by the sand filtration tower. In the activated carbon tower, an oxidizable substance (hereinafter sometimes referred to as “COD component”) converted to COD (chemical oxygen demand) is removed.
However, in the aeration tank, most of the organic matter (hereinafter sometimes referred to as “BOD component”) converted to BOD (biochemical oxygen demand) contained in coke oven wastewater is treated, but COD Some of the components are sent to the settling tank untreated. And since the load which COD component contained in the supernatant water isolate | separated with the precipitation tank gives to activated carbon is large, it is necessary to replace | exchange the activated carbon with which the activated carbon tower was packed frequently. Therefore, there are problems that operation management is complicated and operation cost is high.
In general, phosphorus compounds (phosphoric acid, phosphates, etc.) added as a nutrient source for sludge may leak into the treated water and cause eutrophication of the wastewater discharge destination.
An object of the present invention is to reduce COD components and total phosphorus concentration in the treated water in the activated sludge treatment of coke oven effluent.

The present invention relates to an aeration tank in which biological treatment with microorganisms in activated sludge is performed on coke oven wastewater, and a membrane separation unit in which solid-liquid separation processing is performed on a treated water biologically treated in the aeration tank. And a COD component wastewater treatment apparatus that removes the COD component contained in the permeated water that has passed through the separation membrane in the membrane separation unit.
The present invention also provides an activated sludge treatment process for performing biological treatment with microorganisms in activated sludge for coke oven wastewater, and a solid-liquid separation treatment with a separation membrane for the treated water biologically treated in the activated sludge treatment process. The present invention provides a coke oven wastewater treatment method including a membrane separation step to be performed and a COD component removal step of removing a COD component contained in the permeated water that has passed through the separation membrane in the membrane separation step.

That is, this invention has the following aspects.
[1] An aeration tank in which biological treatment with microorganisms in activated sludge is performed on coke oven drainage, and a membrane separation unit in which solid-liquid separation processing is performed on a treated water biologically treated in the aeration tank using a separation membrane A coke oven wastewater treatment apparatus comprising: a COD component removal unit that removes a COD component contained in the permeated water that has passed through the separation membrane.
[2] An aeration tank in which biological treatment with microorganisms in activated sludge is performed on coke oven drainage, and a membrane separation unit in which solid-liquid separation processing is performed on a treated water biologically treated in the aeration tank by a separation membrane And a coke oven wastewater treatment apparatus comprising: an activated carbon portion that contacts the permeated water that has passed through the separation membrane and activated carbon.
[3] The coke oven wastewater treatment apparatus according to [1] or [2], wherein the membrane separation unit is installed in the aeration tank or outside the aeration tank.
[4] The coke oven wastewater treatment apparatus according to any one of [1] to [3], wherein the calcium concentration in the aeration tank is 110 mg / L to 170 mg / L.
[5] The coke oven wastewater treatment according to any one of [1] to [4], wherein biological treatment with microorganisms in activated sludge is performed in the aeration tank on the coke oven wastewater diluted with dilution water. apparatus.
[6] The coke oven wastewater treatment apparatus according to [5], wherein a volume ratio of the dilution water / the coke oven wastewater is in a range of (1/1) to (4/1).
[7] The coke oven wastewater treatment apparatus according to [5] or [6], wherein seawater and / or industrial water is used as the dilution water.
[8] The coke oven wastewater treatment apparatus according to any one of [1] to [7], wherein the membrane separation unit includes a separation membrane element including a porous hollow fiber membrane as a constituent member.
[9] The coke according to any one of [1] to [8], wherein a daily average membrane permeation flux of water to be treated in the membrane separation unit is 0.1 m / day to 0.6 m / day. Furnace wastewater treatment equipment.
[10] The coke oven wastewater treatment apparatus according to any one of [1] to [9], wherein an average pore diameter of the separation membrane is 0.03 μm to 0.5 μm.

[11] An activated sludge treatment process in which coke oven wastewater is biologically treated with microorganisms in the activated sludge, and membrane separation in which solid water is separated from the water to be treated biologically treated in the activated sludge treatment process. A coke oven wastewater treatment method comprising: a step, and a COD component removal step of removing a COD component contained in the permeated water that has passed through the separation membrane in the membrane separation step.
[12] An activated sludge treatment process that performs biological treatment with microorganisms in activated sludge on coke oven wastewater, and a membrane separation that performs solid-liquid separation treatment on the treated water biologically treated in the activated sludge treatment process using a separation membrane A method for treating coke oven waste water, comprising: a step; and an activated carbon contact step in which the permeated water that has passed through the separation membrane and activated carbon are brought into contact with each other.
[13] A dilution step of mixing dilution water and coke oven wastewater, and an activated sludge treatment step of performing biological treatment with microorganisms in the activated sludge on the coke oven wastewater diluted with the dilution water obtained in the dilution step, A membrane separation step of performing a solid-liquid separation process using a separation membrane on the treated water biologically treated in the activated sludge treatment step, and a COD component removal step of removing a COD component contained in the permeated water that has passed through the separation membrane And a coke oven wastewater treatment method.
[14] A dilution step of mixing dilution water and coke oven wastewater, and an activated sludge treatment step of performing biological treatment with microorganisms in the activated sludge on the coke oven wastewater diluted with the dilution water obtained in the dilution step, A membrane separation step of performing a solid-liquid separation treatment with a separation membrane on the treated water biologically treated in the activated sludge treatment step, and an activated carbon contact step of bringing the permeated water that has passed through the separation membrane into contact with activated carbon. Including coke oven wastewater treatment method.
[15] Any one of the above [11] to [14], in which the membrane separation step is performed by a solid-liquid separation process using the separation membrane installed in or outside the aeration tank in which the biological treatment is performed. The coke oven waste water treatment method according to item.
[16] The coke oven waste water treatment method according to any one of [11] to [15], wherein the calcium concentration in the aeration tank is 110 mg / L to 170 mg / L.
[17] The method according to [13] or [14], wherein in the dilution step, the volume ratio of the dilution water / the coke oven drainage is adjusted to be in a range of (1/1) to (4/1). Coke oven wastewater treatment method.
[18] The coke oven wastewater treatment method according to [17], wherein the dilution water is seawater and / or industrial water.
[19] The coke oven wastewater treatment method according to any one of [11] to [18], including using a separation membrane element including a porous hollow fiber membrane as a constituent member in the membrane separation step.
[20] In any one of [11] to [19], in the membrane separation step, a daily average membrane permeation flux of water to be treated in the membrane separation unit is 0.1 m / day to 0.6 m / day. The coke oven waste water treatment method according to item 1.
[21] The coke oven wastewater treatment method according to any one of [11] to [20], wherein an average pore diameter of the separation membrane is 0.03 μm to 0.5 μm.

According to the present invention, in coke oven wastewater treatment, COD components in the treated water can be reduced, and the life of the activated carbon can be extended.
In addition, the total phosphorus concentration in the treated water is reduced, and eutrophication of the discharge destination is prevented.

It is the schematic explaining an example of the processing apparatus (membrane separation activated sludge apparatus) of the coke oven waste_water | drain to which this Embodiment is applied. It is a block flow figure explaining an example of a processing device of coke oven drainage to which this embodiment is applied. It is a block flow figure explaining the example of the processing apparatus of the conventional coke oven waste_water | drain.

Hereinafter, embodiments of the present invention will be described in detail.
In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary. That is, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention, but are merely illustrative examples, unless otherwise specified. .
The drawings used are examples for explaining the present embodiment and do not represent actual sizes. The size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation.

<Coke oven wastewater treatment equipment>
FIG. 1 is a schematic diagram illustrating an example of a coke oven wastewater treatment apparatus 100 (membrane separation activated sludge apparatus) to which the present embodiment is applied.
FIG. 2 is a block flow diagram illustrating an example of a coke oven wastewater treatment apparatus to which the present embodiment is applied. FIG. 2A shows the first embodiment, and FIG. 2B shows the second embodiment.
In addition, in FIG. 1, the conventional processing apparatus 200 (precipitation method activated sludge apparatus) is described collectively.

A coke oven wastewater treatment apparatus 100 shown in FIG. 1 includes a raw water tank 1 for storing coke oven wastewater (A) (hereinafter, referred to as “raw water (A)”) introduced from the outside, and a raw water tank. The aeration tank (activated sludge apparatus) 2 for biologically treating the BOD component contained in the raw water 1 with microorganisms in the activated sludge, and the treated water biologically treated in the aerated tank 2 are solid-liquid separated by the membrane separation unit 10. A membrane separation tank 8 and an activated carbon tower (COD component removal section) 15 that adsorbs and removes COD components contained in the permeated water that has permeated through the membrane separation section 10 by solid-liquid separation in the membrane separation tank 8 are provided.
In the present embodiment, the membrane separation unit 10 is composed of a separation membrane module in which a plurality of separation membrane elements provided with a separation membrane are arranged.
Moreover, in this Embodiment, the membrane separation tank 8 is installed in the exterior of the aeration tank 2 (1st Embodiment).

(First embodiment)
Next, based on FIG.1 and FIG.2 (a), the flow of the process by the processing apparatus 100 of coke oven waste_water | drain is demonstrated.
As shown in FIG. 1, raw water (A) is introduced and stored in the raw water tank 1 from the outside via a raw water pipe 21. The raw water (A) stored in the raw water tank 1 is supplied to the aeration tank (activated sludge apparatus) 2 via the pipe 22 by the pump (P1) 41.
Diluted water (B) is added to the raw water (A) in the aeration tank 2 via the supply pipe 23 to dilute the raw water (A). In the present embodiment, seawater and industrial water are used as the dilution water (B).
Moreover, in this Embodiment, the phosphorus compound (for example, phosphoric acid) is added in the aeration tank 2 through the supply piping 23 as a nutrient source of activated sludge.

In the aeration tank 2, biological treatment with microorganisms in the activated sludge is performed on the raw water (A) diluted with the diluted water (B), and most of the BOD components are decomposed. Also, the amount of COD component is reduced.
Note that air is supplied to the aeration tank 2 from an air blower (B1) 42 provided outside via an air diffusion pipe 24 through an air diffusion pipe 3 provided in the aeration tank 2. The BOD component is aerobically oxidized and decomposed by the air released from the air diffuser 3. The water level in the aeration tank 2 is controlled by a level switch 4, and the dissolved oxygen amount is monitored by a dissolved oxygen meter 5.

  The treated water biologically treated in the aeration tank 2 is sent to the membrane separation tank 8 through the pipe 31 by a pump (P4) 51 provided in the aeration tank 2. The treated water sent to the membrane separation tank 8 is subjected to solid-liquid separation processing by the membrane separation unit 10 immersed in the membrane separation tank 8, and sludge is separated from the treated water (solid-liquid separation). In the present embodiment, suction filtration by the pump (P5) 53 is performed via the pipe 32 connected to the membrane separation unit 10. The permeated water that has passed through the membrane separation unit 10 is sent to the activated carbon tower (COD component removal unit) 15 via the pipe 33.

Here, as the COD component removal unit, a coagulation-precipitation apparatus using an aggregating agent such as aluminum sulfate, PAC, ferric chloride, ferric sulfate, or polyferric ferric sulfate, an activated carbon tower, or the like can be used. In the embodiment, the COD component removing unit is not particularly limited. For example, an activated carbon tower 15 filled with activated carbon can be used.
In the activated carbon tower 15, the COD component contained in the permeated water is adsorbed and removed by activated carbon, and then discharged from the bottom as treated water (D) suitable for discharge or reuse from the bottom of the activated carbon tower 15 through the drain pipe 34. Discharged.
The activated carbon packed in the activated carbon tower 15 is usually a porous material having fine pores (diameter of about 1 nm to 20 nm) made by reacting with a gas or a chemical at a high temperature using a carbon material such as coal or coconut grains as a raw material. However, the shape is not particularly limited, and for example, a fibrous shape, a honeycomb shape, a columnar shape, a crushed shape, a granular shape, a powdery shape, or the like is appropriately selected and used.

Note that air is supplied to the membrane separation tank 8 from an air blower (B2) 52 provided outside through a diffuser tube 9 provided in the membrane separation tank 8. The water level in the membrane separation tank 8 is controlled by a level switch 11. Further, the sludge separated by the membrane separation unit 10 is returned to the aeration tank 2 as return sludge by the pump (P6) 54 via the return pipe 35, and a part of the return sludge is extracted out of the system as surplus sludge. Will be disposed of.
Next, each apparatus which comprises the processing apparatus 100 (membrane separation activated sludge apparatus) of coke oven waste_water | drain is demonstrated.

(Aeration tank (activated sludge device) 2)
In the aeration tank (activated sludge apparatus) 2, a biological treatment is performed in which oxygen is given to aerobic microorganisms in the activated sludge to decompose organic substances in the coke oven wastewater (raw water (A)).
Examples of biological treatment with aerobic microorganisms in activated sludge include standard activated sludge method, long-time aeration method, oxidation ditch (OD) method, step aeration method, and membrane separation activated sludge method. In the present embodiment, a membrane separation activated sludge method that combines biological treatment in the aeration tank (activated sludge apparatus) 2 and physical treatment by membrane filtration in the membrane separation tank 8 is employed.
For biological treatment of organic matter in coke oven effluent (raw water (A)), it is preferable to use bacteria cultured (acclimated) in coke oven effluent containing phenol, CN, SCN, NH _{4 and the} like. Examples of the bacterial species include thiocyan assimilating bacteria.

As described above, it is preferable that the dilution water (B) is added to the raw water (A) in the aeration tank 2 to dilute the raw water (A).
In the present embodiment, the coke oven wastewater (raw water (A)) contains components having biotoxicity such as ammonia, cyanide, thiocyanate, phenol, etc., so that the load is reduced when flowing into the aeration tank 2. It is preferable to dilute with dilution water (B).
The ratio (volume ratio) of the dilution water (B) and the raw water used for diluting the raw water (A) is usually the ratio (volume ratio) of the dilution water (B) / raw water (A) (1/1) to (4). / 1), preferably (2/1) to (3/1).
Moreover, seawater, industrial water, river water, etc. can be utilized for dilution water (B). You may use these 1 type or in mixture of 2 or more types.

In this Embodiment, it is preferable to use seawater and / or industrial water as dilution water (B). Thereby, the calcium concentration in the aeration tank 2 can be adjusted to an optimal range.
Here, when seawater and industrial water are used as the dilution water (B), the ratio (volume ratio) of seawater / industrial water in the dilution water (B) is (5/1) to (0.5 / 1). ) Range is preferable, and (1/1) is more preferable.

In the present embodiment, when diluting the raw water (A), the calcium concentration in the aeration tank 2 is preferably 100 mg / L to 200 mg / L, and preferably 110 mg / L to 170 mg / L. More preferably, it is particularly preferably from 125 mg / L to 155 mg / L.
Here, in order to adjust raw water (A) to the said density | concentration, it is preferable to use the said dilution water (B). Thereby, the mixing ratio of the seawater with respect to the waste water after mixing can be about 25% by volume to 40% by volume.
Here, when the calcium concentration is excessively high, calcium carbonate is deposited in the aeration tank 2 and the volume of the aeration tank 2 tends to decrease.
Moreover, when calcium is too low, the sedimentation rate of sludge tends to decrease, and the efficiency of solid-liquid separation by the membrane separation unit 10 of the membrane separation tank 8 tends to decrease, and the differential pressure of the membrane separation unit 10 increases. Tend to.

In the present embodiment, the phosphorus compound as a nutrient source of the activated sludge has a ratio of the BOD component and the phosphorus compound (P) contained in the raw water (A) such that (BOD component: P) = (100: 0.3 ) To (100: 1) (weight ratio), it is preferably added to the raw water (A).
When the processing apparatus 100 is actually operated, if the addition amount of the phosphorus compound is set higher than the above-mentioned ratio, it is possible to cope with fluctuations in the concentration of organic substances contained in the raw water (A). However, when the addition amount of the phosphorus compound is excessively large, it tends to leak into excess phosphorus compound treated water and cause eutrophication of the drainage discharge destination.

In this embodiment, it is preferable COD volume loading in the aeration tank 2 to 1kg / ^{(m 3} · day) ~3kg / ^{(m 3} · day) approximately ranges.
Moreover, 30-40 degreeC is preferable and the water temperature of the aeration tank 2 has more preferable 33-35 degreeC. When the water temperature of the aeration tank 2 is excessively low or high, the activity of the bacteria in the activated sludge is lowered, and the degradability of COD components and SCN contained in the raw water (A) tends to be affected.

(Membrane separation tank 8)
In the membrane separation tank 8 provided outside the aeration tank 2, the water to be treated is subjected to solid-liquid separation processing by the membrane separation unit 10 immersed in the membrane separation tank 8. Examples of the separation membrane disposed in the membrane separation unit 10 include a microfiltration membrane (MF membrane) and an ultrafiltration membrane.
The shape of the separation membrane includes a type using a hollow fiber membrane and a type using a flat membrane. The type using the hollow fiber membrane can increase the integration density of the membrane as compared with the type using the flat membrane. In particular, the membrane filtration unit is preferable because it is compact and has a small amount of aerated air.
Examples of the material constituting the separation membrane include organic substances such as cellulose, polyolefin, polysulfone, polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE); and inorganic substances such as ceramics.

The configuration of the membrane separation unit 10 is not particularly limited. In the present embodiment, a hollow fiber membrane module obtained by arranging a plurality of sheet-like hollow fiber membrane elements in which a large number of porous hollow fiber membranes are arranged in parallel on the same plane at a predetermined interval, and this hollow fiber It is preferable to use in combination with a diffuser generator (a diffuser tube 9, a blower (B2) 52) disposed below the membrane module. The hollow fiber membrane module is composed of a plurality of hollow fiber membrane elements, and the overall shape is a substantially rectangular parallelepiped.
In addition, from the viewpoint of processing efficiency, the average pore diameter of the porous hollow fiber is preferably 0.03 μm to 0.5 μm.

In this embodiment, a hollow fiber membrane module including a porous hollow fiber membrane element made of PVDF is used as the membrane separation unit 10. In this case, from the viewpoint of the operational stability and economic efficiency of the membrane module, the daily average membrane permeation flux of the water to be treated is preferably 0.1 m / day to 0.6 m / day. More preferably, it is performed in the range of 2 m / day to 0.5 m / day, and more preferably in the range of 0.25 m / day to 0.45 m / day.
In order to prevent sludge from adhering to the porous hollow fiber membrane and blocking the membrane, it is preferable to always perform aeration from the air diffusion tube 9.
Furthermore, it is preferable to intermittently perform suction filtration with the pump (P5) 53 in order to prevent the membrane from being blocked. Specifically, for example, suction filtration (7 minutes) -stop (1 minute) is performed.

In addition, when using the processing apparatus 100 which has the membrane separation tank 8 provided in the exterior of the aeration tank 2, the separation sludge separated by the membrane separation part 10 is the sludge return ratio between the aeration tank 2 and the membrane separation tank 8. 1 to 5, preferably 2 to 3 is preferably returned.
The activated sludge suspended solid (MLSS) in the aeration tank 2 is in the range of 4,000 mg / L to 10,000 mg / L, preferably 6,000 mg / L to 8,000 mg / L.
The MLSS of the membrane separation tank 8 is preferably in the range of 5,000 mg / L to 15,000 mg / L, preferably 8,000 mg / L to 12,000 mg / L.

(Second Embodiment)
Next, based on FIG.2 (b), 2nd Embodiment of the processing apparatus of coke oven waste water is described. As shown in FIG. 2B, in the present embodiment, the membrane separation unit 10 is disposed so as to be immersed in the aeration tank 2.
In this Embodiment, the organic substance in raw | natural water (A) is activated in the same aeration tank 2 provided with the diffuser tube 3 and the membrane separation part 10 which send air into raw | natural water (A) from the air blower (B1) 42. Biological treatment that decomposes by microorganisms in the sludge and solid-liquid separation treatment by the membrane separation unit 10 are performed. The solid-liquid separation process is performed by suction filtration using a pump connected to the membrane separation unit 10. The permeated water that has passed through the membrane separation unit 10 is sent to the activated carbon tower 15 by a pump (P5) 53. In the activated carbon tower 15, the COD component contained in the permeated water is adsorbed and removed by activated carbon, and then discharged from the bottom as treated water (D) suitable for discharge or reuse from the bottom of the activated carbon tower 15 through the drain pipe 34. Discharged.
In addition, when the membrane separation part 10 is immersed and arrange | positioned inside the aeration tank 2 like this Embodiment, MLSS of the aeration tank 2 is 6,000 mg / L-15,000 mg / L. It is preferable to be in the range.

In the coke oven wastewater treatment apparatus 100 to which the present embodiment is applied, when the membrane separation unit 10 is immersed in the membrane separation tank 8 installed outside the aeration tank 2 (first embodiment) ) Is an air diffuser (air diffuser 3, air blower (B1) 42) necessary for biological treatment in the aeration tank 2, and an air diffuser necessary for cleaning the membrane separator 10 immersed in the membrane separator 8 ( For the air diffuser 9 and the blower (B2) 52), a method suitable for each tank can be adopted.
Further, the MLSS of the aeration tank 2 can be operated lower than the MLSS of the membrane separation tank 8. Furthermore, solid-liquid separation processing can be performed without stopping the operation of the aeration tank 2 at the time of inspection / repair / replacement of the separation unit membrane element by providing cooperation with other systems and providing a plurality of separation unit membrane elements. it can.

Further, in the coke oven wastewater treatment apparatus 100 to which the present embodiment is applied, when the membrane separation unit 10 is immersed in the aeration tank 2 (second embodiment), the process configuration is as follows. Simplified. Further, aeration by the diffusing tube 3 provided inside the aeration tank 2 can be used for cleaning the membrane separation unit 10.
Furthermore, by cooperating with other systems and placing a plurality of separation part membrane elements in the aeration tank 2, the operation of the aeration tank 2 is not suspended when the separation part membrane elements are inspected, repaired or replaced. A solid-liquid separation process can be performed.

In addition, by operating the coke oven wastewater treatment apparatus 100 to which the present embodiment is applied, the total phosphorus concentration of the treated water is lowered. The reason why the total phosphorus concentration in the treated water is lowered is considered as follows.
That is, in this embodiment, the pH (hydrogen ion concentration index) of coke oven wastewater (raw water (A)) is usually on the alkali side (pH 8 to pH 9.5), and ammonia derived from coke oven wastewater (after mixing) 800 mg / L to 1,000 mg / L).
At this time, if a certain amount of magnesium (Mg) is present, the phosphorus compound added as a nutrient source of sludge is a crystal of poorly soluble magnesium ammonium phosphate (hereinafter sometimes referred to as “MAP”). It should be deposited.
Further, if a certain amount of calcium (Ca) is present, the phosphorus compound added as a nutrient source for sludge should be precipitated as hardly soluble calcium phosphate crystals.

Therefore, as described above, seawater as dilution water is added to the raw water (A) at a predetermined ratio, and magnesium (Mg) and / or calcium (Ca) that is hardly contained in the coke oven drainage (raw water (A)). If the amount is adjusted, MAP and / or calcium phosphate crystals are precipitated as insoluble substances.
Thereafter, the MAP and / or calcium phosphate, which is an insoluble substance, is separated by the membrane separation unit 10 to obtain treated water from which most of the phosphorus compound added as a nutrient source for sludge has been removed.
That is, by the coke oven wastewater treatment apparatus 100 to which the present embodiment is applied, fine MAP and / or calcium phosphate crystals that could not be removed by the sedimentation tank 6 and the sand filtration tower 13 provided in the conventional treatment apparatus 200. Can be prevented, and phosphorus leakage can be prevented.

  Hereinafter, the present invention will be described more specifically based on examples and comparative examples. In addition, this invention is not limited to a following example, unless the summary is exceeded.

(Example)
The coke oven wastewater treatment apparatus 100 shown in FIG. 1 was used, and activated sludge treatment of coke oven wastewater was performed by the membrane separation activated sludge method (MBR) based on the following operating conditions. The measurement results of the water quality measured for the raw water before treatment (A: treated water) and the treated water after treatment are shown in Table 1 described later.

(1) Treated water (coke oven drainage)
・ Water flow rate: 0.1 m ³ / h (flow rate before dilution)
0.3 m ³ / h (flow rate after dilution with seawater and industrial water)

(2) Treatment conditions of the aeration tank 2 / Addition ratio of seawater / industrial water: coke oven wastewater: seawater: industrial water = 1: 1: 1
・ Capacity of aeration tank 2: 4 m ³
-Calcium concentration in the aeration tank 2: 110 mg / L to 170 mg / L
・ Phosphorus addition amount: average 10 mg-P / L (phosphoric acid addition)
COD volumetric load: 2.6 kg / (m ³ · day) on average
・ Water temperature: 33 ℃ ~ 35 ℃
MLSS: 7,000 mg / L to 8,000 mg / L
・ Dissolved oxygen: Average 1mg / L

(3) Processing conditions of membrane separation tank 8 (outer tank type membrane separation apparatus) Membrane separation part 10: Membrane area 18 m using a hollow fiber membrane element provided with a PVDF hollow fiber membrane (average pore diameter 0.4 μm) ² hollow fiber membrane modules (Mitsubishi Rayon Co., Ltd.) were used.
- always bubbling air ^{volume: 10Nm 3 / m 2 · h~20Nm} 3 / m 2 · h
・ Removal time of treated water: 7 minutes, withdrawal stop time: 1 minute ・ Sludge return ratio from membrane separation tank 8 to aeration tank 2: 2
-Daily average permeation flux of membrane (membrane separation unit 10): 0.4 m / day

(4) Treatment conditions and space velocity of activated carbon tower 15 (COD removal section): 5 (m ³ / h) / (m ³ -AC)
-Charging amount of activated carbon: 0.06m ³
-Layer height of activated carbon: 1,900mmH
・ Dimension of activated carbon tower 15: 200 mmφ × 3,000 mmH (cross-sectional area 0.031 m ² )
・ Water flow LV: 9.7 m / h
・ COD when activated carbon tower 15 breaks through: 60 mg / L

(Comparative example)
The coke oven wastewater treatment apparatus 200 (precipitation activated sludge apparatus) shown in FIG. 1 was used, and activated sludge treatment of coke oven wastewater was performed by the precipitation method based on the following operating conditions.
Hereinafter, a conventional processing apparatus 200 will be described with reference to FIGS. 1 and 3.

A conventional treatment apparatus 200 for coke oven waste water shown in FIG. 1 includes a raw water tank 1, an aeration tank 2, a precipitation tank 6 into which treated water containing activated sludge overflowing from the aeration tank 2 flows, and a precipitation tank 6. A treated water tank 12, a sand filtration tower 13 and an activated carbon tower 14 into which the supernatant liquid separated by the activated sludge precipitation is provided.
Similarly to the treatment apparatus 100 (membrane separation activated sludge apparatus), the raw water (A) in the raw water tank 1 is supplied to the aeration tank 2 and biological treatment is performed by microorganisms in the activated sludge. Next, the water to be treated containing activated sludge overflowing from the aeration tank 2 flows into the sedimentation tank 6 equipped with the sludge scraper 7 via the pipe 25, and the activated sludge settles in the sedimentation tank 6 to obtain a supernatant liquid. And sludge (return sludge). The return sludge is returned to the aeration tank 2 as return sludge through the return pipe 30 by the pump (P2) 44, and a part of the return sludge is extracted out of the system as surplus sludge and disposed.
The supernatant liquid separated in the sedimentation tank 6 flows into the treated water tank 12 through the pipe 26, and then sent to the sand filtration tower 13 through the pipe 27 by the pump (P 3) 43, and further through the pipe 28 to the activated carbon tower 14. And discharged from the bottom of the activated carbon tower 14 through the drain pipe 29 as treated water (C).
The measurement results of the water quality measured for the treated water after treatment by the conventional treatment apparatus 200 and the raw water before treatment (treated water) are shown in Table 1 described later.

(1) Treated water (coke oven wastewater): Same as in Example 1 (2) Treatment conditions of aeration tank 2: Same as in Example 1 (3) Treatment conditions of precipitation tank 6 / Surface load: 14.3 m / day -Sludge return ratio from settling tank 6 to aeration tank 2: 1
(4) Processing conditions, filter medium, bed height of sand filtration tower 13: Anthracite: 1,200 mmH
Filter sand: 700mmH
・ Size of sand filtration tower 13: 150 mmφ × 3,000 mmH (cross-sectional area 0.018 m ² )
-Filtration LV: 17 m / h
(5) Treatment conditions of activated carbon tower 14: same as in Example 1

Here, the lifetime of the activated carbon was determined as follows.
In an Example, the treated water of the membrane separation part 10 is passed through the activated carbon tower 15, and in the comparative example, the treated water of the sand filtration tower 13 is passed through the activated carbon tower 14, and each activated carbon tower treated water is 12-14. Samples were taken every hour and COD was measured.
The COD of the activated carbon tower treated water increases with the passage of time, and the number of days of water passage from the beginning of the water flow to the breakthrough point is calculated with the point when the COD of the activated carbon tower inlet water reaches 60%. It was.
Moreover, in the Example and the comparative example, this evaluation was each performed 3 times and the average value of the water permeation days was evaluated as the lifetime of activated carbon.

From the results shown in Table 1, in the activated sludge treatment of coke oven wastewater, the coke oven wastewater (raw water (A)) is diluted at a ratio of coke oven wastewater (raw water): seawater: industrial water = 1: 1: 1, Adjust the calcium concentration in the aeration tank 2 by adding phosphoric acid so that the added amount of phosphorus becomes an average of 10 mg-P / L as a nutrient source of activated sludge while keeping the calcium concentration in the range of 110 mg / L to 170 mg / L Then, after the activated sludge treatment in the aeration tank 2, the treated water subjected to the solid-liquid separation treatment by the membrane separation unit 10 equipped with the PVDF hollow fiber membrane (Example) is untreated coke oven wastewater (raw water) Compared with (A)), the COD component (COD (mg / L)) is reduced to about 1.8% (79 mg / L) of the raw water (A), and the BOD component (BOD (mg / L)) ) Reduced to about 0.25% (7.6 mg / L) of raw water (A) And the life of the activated carbon packed in the activated carbon column 15 is extended, the number of days to be replaced is an average of 16 days.
Furthermore, the total phosphorus concentration (TP (total phosphorus) (mg / L)) decreased to about 0.6% (0.06 mg / L) of the raw water (A).

On the other hand, when the coke oven waste water similar to the example was treated with activated sludge using the conventional treatment device 200 (precipitation activated sludge device) (comparative example), the reduction of COD components was reduced in the raw water (A). Example: The number of days for which the activated carbon charged in the activated carbon tower 14 should be replaced is approximately 2.5% (110 mg / L), the decrease in the BOD component is only approximately 1.8% (55 mg / L) of the raw water. As a result, it stopped on average 11 days.
Furthermore, the decrease of TP (total phosphorus) was stopped at about 7% (0.7 mg / L) of raw water.

As mentioned above, according to this invention, it replaces with the sedimentation tank 6 and the sand filtration tower 13 of the conventional coke oven waste water treatment equipment, and by providing the membrane separation part 10, the COD component of the activated carbon tower 15 inlet_port | entrance reduces, and activated carbon Can extend the lifespan.
Moreover, eutrophication of a discharge destination can be prevented by reducing the total phosphorus concentration in the treated water.

DESCRIPTION OF SYMBOLS 1 ... Raw water tank, 2 ... Aeration tank, 3, 9 ... Aeration pipe, 4, 11 ... Level switch, 5 ... Dissolved oxygen meter, 6 ... Precipitation tank, 7 ... Sludge scraper, 8 ... Membrane separation tank, 10 ... Membrane separation unit, 12 ... treated water tank, 13 ... sand filtration tower, 14, 15 ... activated carbon tower, 21 ... raw water piping, 22, 25, 26, 27, 28, 31, 32, 33 ... piping, 23 ... supply piping, 24 ... Aeration pipe, 29, 34 ... Drain pipe, 30, 35 ... Return pipe, 41, 43, 44, 51, 53, 54 ... Pump, 42, 52 ... Blower, 100 ... Treatment device (membrane separation activated sludge Equipment), 200 ... treatment equipment (precipitation activated sludge equipment), A ... coke oven waste water, B ... dilution water, C, D ... treated water

Claims (21)

An aeration tank in which a phosphorus compound is added as a nutrient source of the activated sludge, and the biological treatment by the microorganisms in the activated sludge is performed on the coke oven drainage,
A membrane separation unit in which a solid-liquid separation process using a separation membrane is performed on water to be treated biologically treated in the aeration tank;
A COD component removing unit that removes a COD component contained in the permeated water that has passed through the separation membrane;
I have a,
The phosphorus compound added to the aeration tank is such that the ratio of the BOD component to the phosphorus compound contained in the coke oven waste water is (BOD component: phosphorus compound) = (100: 0.3) to (100: 1) (weight) Coke oven wastewater treatment equipment characterized by being in a range of An aeration tank in which a phosphorus compound is added as a nutrient source of the activated sludge, and the biological treatment by the microorganisms in the activated sludge is performed on the coke oven drainage,
A membrane separation unit in which a solid-liquid separation process using a separation membrane is performed on water to be treated biologically treated in the aeration tank;
An activated carbon part for bringing the permeated water that has passed through the separation membrane into contact with activated carbon;
I have a,
The phosphorus compound added to the aeration tank is such that the ratio of the BOD component to the phosphorus compound contained in the coke oven waste water is (BOD component: phosphorus compound) = (100: 0.3) to (100: 1) (weight) Coke oven wastewater treatment equipment characterized by being in a range of   The coke oven wastewater treatment apparatus according to claim 1 or 2, wherein the membrane separation unit is installed in the aeration tank or outside the aeration tank.   The coke oven wastewater treatment apparatus according to any one of claims 1 to 3, wherein a calcium concentration in the aeration tank is 110 mg / L to 170 mg / L.   The coke oven wastewater treatment apparatus according to any one of claims 1 to 4, wherein biological treatment with microorganisms in activated sludge is performed in the aeration tank on the coke oven wastewater diluted with dilution water. .   6. The coke oven waste water treatment apparatus according to claim 5, wherein a volume ratio of the dilution water / the coke oven waste water is in a range of (1/1) to (4/1).   Seawater and / or industrial water are used as said dilution water, The coke oven wastewater processing apparatus of Claim 5 or 6 characterized by the above-mentioned.   The coke oven wastewater treatment apparatus according to any one of claims 1 to 7, wherein the membrane separation unit includes a separation membrane element including a porous hollow fiber membrane as a constituent member.   The coke oven according to any one of claims 1 to 8, wherein a daily average membrane permeation flux of water to be treated in the membrane separation unit is 0.1 m / day to 0.6 m / day. Wastewater treatment equipment.   10. The coke oven wastewater treatment apparatus according to claim 1, wherein an average pore diameter of the separation membrane is 0.03 μm to 0.5 μm. An activated sludge treatment process in which a phosphorus compound is added as a nutrient source of the activated sludge, and the biological treatment of the coke oven wastewater with microorganisms in the activated sludge is performed;
A membrane separation step of performing a solid-liquid separation treatment with a separation membrane on the treated water biologically treated in the activated sludge treatment step;
A COD component removal step of removing COD components contained in the permeated water that has passed through the separation membrane in the membrane separation step;
Only including,
In the activated sludge treatment step, the ratio of the BOD component and the phosphorus compound contained in the coke oven effluent is determined as follows: (BOD component: phosphorus compound) = (100: 0.3) to (100: 1) (weight) The coke oven wastewater treatment method is characterized in that it is added so as to be in a range of An activated sludge treatment process in which a phosphorus compound is added as a nutrient source of the activated sludge, and the biological treatment of the coke oven wastewater with microorganisms in the activated sludge is performed;
A membrane separation step of performing a solid-liquid separation treatment with a separation membrane on the treated water biologically treated in the activated sludge treatment step;
An activated carbon contact step of bringing the permeated water that has passed through the separation membrane into contact with activated carbon;
Only including,
In the activated sludge treatment step, the ratio of the BOD component and the phosphorus compound contained in the coke oven effluent is determined as follows: (BOD component: phosphorus compound) = (100: 0.3) to (100: 1) (weight) The coke oven wastewater treatment method is characterized in that it is added so as to be in a range of A dilution process for mixing dilution water and coke oven waste water;
An activated sludge treatment step of adding a phosphorus compound as a nutrient source of the activated sludge, and performing biological treatment with microorganisms in the activated sludge for coke oven wastewater diluted with the dilution water obtained in the dilution step;
A membrane separation step of performing a solid-liquid separation treatment with a separation membrane on the treated water biologically treated in the activated sludge treatment step;
And COD component removing step of removing COD components contained in the permeated water having passed through the separation membrane, only including,
In the activated sludge treatment step, the ratio of the BOD component and the phosphorus compound contained in the coke oven effluent is determined as follows: (BOD component: phosphorus compound) = (100: 0.3) to (100: 1) (weight) The coke oven wastewater treatment method is characterized in that it is added so as to be in a range of A dilution process for mixing dilution water and coke oven waste water;
An activated sludge treatment step of adding a phosphorus compound as a nutrient source of the activated sludge, and performing biological treatment with microorganisms in the activated sludge for coke oven wastewater diluted with the dilution water obtained in the dilution step;
A membrane separation step of performing a solid-liquid separation treatment with a separation membrane on the treated water biologically treated in the activated sludge treatment step;
An activated carbon contact step of bringing the permeated water that has passed through the separation membrane into contact with activated carbon;
Only including,
In the activated sludge treatment step, the ratio of the BOD component and the phosphorus compound contained in the coke oven effluent is determined as follows: (BOD component: phosphorus compound) = (100: 0.3) to (100: 1) (weight) The coke oven wastewater treatment method is characterized in that it is added so as to be in a range of   15. The solid-liquid separation process according to claim 11, wherein the membrane separation process is performed by the separation membrane installed in an aeration tank in which the biological treatment is performed or outside the aeration tank. The coke oven waste water treatment method according to claim 1. The method for treating coke oven waste water according to claim 15 , wherein the calcium concentration in the aeration tank is 110 mg / L to 170 mg / L.   The said dilution process WHEREIN: It adjusts so that the volume ratio of the said dilution water / the said coke oven waste_water | drain may become the range of (1/1)-(4/1). Coke oven wastewater treatment method.   The method for treating coke oven waste water according to claim 17, wherein the dilution water is seawater and / or industrial water.   The method for treating coke oven waste water according to any one of claims 11 to 18, wherein the membrane separation step includes using a separation membrane element having a porous hollow fiber membrane as a constituent member. The membrane average film flux date of separation step definitive treatment water, 0.1 m / day ～0.6M / day coke according to any one of claims 11 to 19, characterized in that is Furnace wastewater treatment method.   21. The coke oven wastewater treatment method according to any one of claims 11 to 20, wherein an average pore diameter of the separation membrane is 0.03 [mu] m to 0.5 [mu] m.

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