CN102730903A - Processing device of drained water with organic matters - Google Patents

Abstract

The object of the present invention is to provide a treatment device for wastewater containing organic matter, which can improve the performance of aerobic biological treatment after anaerobic biological treatment of wastewater containing organic matter and membrane separation treatment of aerobic biologically treated water. Membrane filterability of aerobic biological treatment sludge maintains high membrane flux and reduces the frequency of drug washing. The treatment device for wastewater containing organic matter of the present invention has: an anaerobic biological treatment tank (1) for anaerobic biological treatment of wastewater containing organic matter; An aerobic biological treatment tank (2) for carrying out aerobic biological treatment of the biologically treated water; and a membrane separation device (5) for solid-liquid separation of the aerobic biologically treated water in the aerobic biological treatment tank (2) ), characterized in that a biological fixed bed (4) is provided in the aerobic biological treatment tank (2).

Description

Treatment device for wastewater containing organic matter

technical field

The invention relates to a treatment device for organic matter-containing drainage, which performs aerobic biological treatment after anaerobic biological treatment and performs membrane separation treatment on aerobic biologically treated water, in particular to a treatment device for organic matter-containing drainage The treatment device, as the aerobic biological treatment tank after the anaerobic biological treatment tank, adopts the membrane separation activated sludge type aerobic biological treatment tank, which improves the membrane filterability of the aerobic biological treatment sludge and The water permeation (flux) of the membrane is improved.

Background technique

Conventionally, as a treatment method for organic-matter-containing wastewater, a method is known in which anaerobic biological treatment is performed on organic-matter-containing wastewater, followed by aerobic biological treatment and solid-liquid separation of aerobic biologically treated water (e.g. , Patent Document 1).

In addition, a membrane separation activated sludge method in which activated sludge is concentrated using a membrane separation device is also known as a solid-liquid separation facility for aerobic biological treatment of water (for example, Patent Document 2).

When a membrane separation device is used as a solid-liquid separation device for aerobic biological treatment of water, the amount of metabolites that cause membrane fouling is less in anaerobic biological treatment than in aerobic biological treatment. Therefore, Compared with the case of directly performing aerobic biological treatment on wastewater containing organic matter (raw water) followed by membrane separation treatment, when anaerobic biological treatment is performed before aerobic biological treatment, membrane fouling can be reduced, reducing Membrane drug wash frequency.

In addition, as a treatment method for wastewater containing organic matter, a multi-stage activated sludge method utilizing the predation of microscopic animals such as protozoa or metazoans upstream of bacteria (biological chain) is known, and it has been put into practical use (e.g. , Patent Document 3). In the multi-stage activated sludge method, first, the organic matter-containing wastewater is treated with bacteria in the first biological treatment tank, and then the organic matter contained in the wastewater is oxidized and decomposed, and converted into non-cohesive bacterial cells, and passed through the second 2. Microscopic animals fixed in the biological treatment tank are preyed and removed, thereby reducing the amount of excess sludge and operating under high load.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2007-175582

Patent Document 2: Japanese Patent Laid-Open No. 2009-297688

Patent Document 3: Japanese Patent Laid-Open No. 2006-51414

Contents of the invention

As mentioned above, in the case of using a membrane separation device for solid-liquid separation of aerobic biological treatment water, by performing anaerobic biological treatment in the previous stage of aerobic biological treatment, the membrane damage caused by metabolites can be reduced. Pollution, however, in anaerobic biological treatment, compared with aerobic biological treatment, the amount of slime produced is less, and the formation of flocs is weaker, so it will be in the anaerobic biological treatment of water and then in good Oxygen biologically treated water contains fine SS components with a diameter of less than 10 μm. These fine SS components will form a dense filter cake layer on the surface of the membrane during the membrane separation process, which will easily increase the transmembrane pressure difference. Therefore, in the case of performing aerobic biological treatment on anaerobic biologically treated water and performing solid-liquid separation with a membrane separation device to obtain clear treated water without SS components, there is a problem that high membrane flux cannot be obtained. Quantity; frequent membrane cleaning is required.

The object of the present invention is to solve the above-mentioned conventional problems, and to provide a treatment device for wastewater containing organic matter, that is, after anaerobic biological treatment is performed on wastewater containing organic matter, aerobic biological treatment is performed and aerobic biological treatment is performed. When the treated water is subjected to membrane separation treatment, the membrane filterability of aerobic biological treatment sludge is improved to maintain high membrane flux and reduce the frequency of chemical washing.

As a result of intensive research by the present inventors to solve the above-mentioned problems, it has been found that by installing a biological fixed bed in an aerobic biological treatment tank of membrane separation activated sludge type, microscopic animals that prey on fine SS components, especially those with high removal ability, can be found. The filtering and predatory microscopic animals of the bdelloid rotifers provide a foothold, so that these microscopic animals are preferentially increased in the aerobic biological treatment tank, and these microscopic animals effectively prey on the fine SS generated in the anaerobic biological treatment, by This improves the membrane filterability of the aerobic biological treatment sludge, and improves the membrane flux of the subsequent membrane separation device.

The present invention was achieved based on the above knowledge, and the gist thereof is as follows.

(1) A treatment device for waste water containing organic matter, comprising: an anaerobic biological treatment tank for anaerobic biological treatment of waste water containing organic matter; An aerobic biological treatment tank for aerobic biological treatment; and a membrane separation device for solid-liquid separation of the aerobic biological treatment water in the aerobic biological treatment tank, characterized in that, in the aerobic biological treatment A biological fixed bed is arranged in the tank.

(2) A treatment device for waste water containing organic matter, wherein in the above (1), the volume of the biological fixed bed is 1 to 30% of the volume of the aerobic biological treatment tank.

(3) A treatment device for wastewater containing organic matter, characterized in that, in the above (1) or (2), the membrane separation device is a submerged membrane separation device immersed in the aerobic biological treatment tank .

(4) A treatment device for wastewater containing organic matter, characterized in that, in the above (3), half of the aerobic biological treatment tank is immersed with the biological fixed bed, and the other half is immersed with the biological fixed bed. The submerged membrane separation device is provided with an aeration device under the submerged membrane separation device.

According to the present invention, by providing a biological fixed bed in the aerobic biological treatment tank, a foothold is provided for microscopic animals that prey on fine SS components, especially bdelloid rotifers with high removal ability, so that these microscopic Animals are preferentially increased in the aerobic biological treatment tank, and these tiny animals can effectively prey on the fine SS generated in the anaerobic biological treatment, thereby improving the membrane filterability of the aerobic biological treatment sludge and maintaining The high membrane flux of the first-class membrane separation device reduces the frequency of drug cleaning and effectively handles it.

Description of drawings

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a graph showing temporal changes in transmembrane pressure difference in Example 1 and Comparative Example 1. FIG.

Wherein, the reference signs are explained as follows:

1 Anaerobic biological treatment tank

2 Aerobic biological treatment tank

3 carrier

4 biological fixed bed

5 membrane modules

6 Diffusers

Detailed ways

Hereinafter, an embodiment of an organic matter-containing wastewater treatment device according to the present invention will be described in detail with reference to the drawings.

Fig. 1 is a system diagram showing an example of an embodiment of the organic matter-containing wastewater treatment device of the present invention. In Fig. 1, reference numeral 1 is an anaerobic biological treatment tank, and reference numeral 2 is an aerobic biological treatment tank . The carrier 3 is filled in the anaerobic biological treatment tank 1 . One half of the aerobic biological treatment tank 2 is submerged with a biological fixed bed 4 , and the other half is submerged with a submerged membrane module 5 , and an air diffuser (aeration device) 6 is provided below the membrane module 5 . Reference signs P ₁ and P ₂ are pumps, and reference sign PI is a pressure gauge.

In FIG. 1 , organic matter-containing wastewater (raw water) is introduced from a pipe 11 to the bottom of an anaerobic biological treatment tank 1 , and anaerobic biological treatment is performed while flowing upward in the anaerobic biological treatment tank 1 . The anaerobic biological treatment water is introduced into the aerobic biological treatment tank 2 from the pipe 12 . The aerobic biological treatment water in the aerobic biological treatment tank 2 is subjected to solid-liquid separation by the membrane module 5, and the membrane permeated water is taken out from the pipe 13 as treated water. Excess sludge is taken out from the pipe 14 .

As the treatment mode of the anaerobic biological treatment tank 1, it is not particularly limited, and besides the fluidized bed type filled with the fluidity carrier 3 as shown in Figure 1, it can also be a fixed bed type treatment tank, in addition, it can also be The following two methods: UASB (Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket: UASB (Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket: Upflow Anaerobic Sludge Blanket) Sludge bed) method; use a reaction tank with a higher height than the UASB method to carry out raw water at a high flow rate, and expand the sludge layer at a high expansion rate to perform anaerobic treatment at a higher load. EGSB ( Expanded Granule Sludge Blanket: Anaerobic expanded granular sludge bed) method.

In addition, it may be a one-phase system in which the acid production reaction and a methane production reaction are performed in the same treatment tank, or a two-phase system in which each reaction is performed in different treatment tanks.

A fluidized bed treatment tank, a fixed bed treatment tank using a carrier, or a treatment tank using particles such as UASB and EGSB are preferable because they can perform high-load treatment with a COD _Cr load of 5 kg/m ³ ·d or more.

The aerobic biological treatment tank 2 shown in FIG. 1 is a submerged membrane separation activated sludge treatment tank in which a membrane module 5 is immersed in the tank. In the tank 2, the membrane separation activated sludge method of the membrane module installed outside the tank 2 can also be used. In the case of the membrane separation activated sludge method installed outside the tank, the membrane module can be immersed in the aeration tank installed separately from the treatment tank 2 to obtain membrane permeated water, and the membrane concentrated water can be circulated to the aerobic biological treatment tank 2 .

In addition to the submerged membrane module, the usual membrane module can also be used, but from the perspective that the power is relatively small, and it is difficult to apply shear force without reducing the size of the sludge, and the clogging of the membrane is not easy to occur. Preference is given to using impregnated membrane modules.

As the type of membrane, MF (microfiltration) membrane and UF (ultrafiltration) membrane, which are excellent in solid-liquid separation of SS, can be used. The type is not particularly limited, and any one of flat membrane, tubular membrane, and hollow fiber membrane can be used. Available.

In the aerobic biological treatment tank 2 of Fig. 1, the diffuser pipe 6 is arranged under the membrane module 5, and by setting the diffuser pipe 6 under the membrane module 5 like this, the membrane surface attachments of the membrane module 5 are removed due to the diffuser. Part of it is stripped and removed by the cleaning effect of the aeration flow, which improves the membrane permeability.

As the biological fixed bed 4 provided in the aerobic biological treatment tank 2, as long as it is a foothold for filtering predatory microscopic animals that prey on microscopic animals of fine SS components, especially bdelloid rotifers with high removal ability, Plastic corrugated boards, nets, honeycomb-shaped materials, materials with ribbons on fibers or ropes, sponge boards, etc., which are usually used in the contact aeration method, can be used to fix the carrier on the treatment tank, especially preferably such as sponge of porous substances. In this case, microscopic animals inhabit the pores of the porous material, and these microscopic animals efficiently prey on the fine SS produced in the anaerobic biological treatment. The pore diameter of the porous substance is preferably about 200 to 1000 μm from the viewpoint of habitat of microscopic animals.

The volume of the biological fixed bed provided in the aerobic biological treatment tank 2 varies according to the presence or absence of the membrane module in the treatment tank 2, and is preferably 1 to 30% relative to the volume of the treatment tank 2, particularly preferably 5 to 30%. 10%.

If the volume of the biological fixed bed is too small, microscopic animals cannot be sufficiently multiplied, and if it is too large, the cost will increase, and in addition, the agitation and mixing of the biological treatment tank will tend to be insufficient. Here, the volume of the biological fixed bed refers to the apparent volume without considering the pores of the porous substance, and the volume of the treatment tank refers to the volume excluding the volume of the membrane module immersed in the tank.

The biological fixed bed 4 installed in the aerobic biological treatment tank 2 is preferably installed in an area where the flow caused by aeration in the treatment tank 2 is small, that is, an area where the sludge rolled up by the diffused air flows downward and sinks. In this way, microscopic animals handling fine SS can easily inhabit the fixed bed.

Therefore, in the aerobic biological treatment tank 2 of Fig. 1, form the following structure: on the half side in the treatment tank 2, the biological fixed bed 4 is dipped and arranged, and the membrane module 5 is dipped and arranged on the other half side, and in the membrane module 5 Dispersing air pipe 6 is arranged below.

In addition, the aerobic biological treatment tank 2 may also be provided in multiple stages, for example, the former stage is used as a denitrification tank, the latter stage is used as a nitrification tank, and the sludge is circulated from the nitrification tank to the denitrification tank. In this case, preferably, the biological fixed bed is installed in the nitrification tank, and the membrane module is installed in the nitrification tank or another aeration tank (membrane immersion tank) for circulating the sludge in the nitrification tank.

As other treatment conditions of the aerobic biological treatment tank 2, it is preferable that the COD _Cr load is 0.7 to 5 kg/m ³ ·day, especially 1 to 2.5 kg/m ³ /day in terms of membrane filterability and treatment efficiency. day; BOD load 0.3-3kg/m ³ ·day, especially 0.5-2kg/m ³ ·day; MLSS concentration 2,000-20,000mg/L, especially 4,000-12,000mg/L.

The organic matter-containing effluent treated by the above-mentioned organic matter-containing effluent treatment device of the present invention is usually biologically treated organic matter-containing effluent, and is not particularly limited. Examples include electronic industry effluent, chemical factory effluent, and food factory effluent. drainage etc. For example, in the manufacturing process of electronic parts, a large amount of organic waste water is generated from the development process, peeling process, etching process, cleaning process, etc., and it is desired to recover the waste water and purify it into pure water for reuse. , These wastewaters are suitable as wastewaters to be treated in the present invention, and high-purity water can be obtained by further advanced treatment of the treated water in the organic matter-containing wastewater treatment device of the present invention.

Examples of the aforementioned organic waste water include: organic waste water containing isopropanol, ethanol, etc.; organic waste water containing organic nitrogen such as monoethanolamine (MEA) and tetramethylammonium hydroxide (TMAH); Drainage; organic drainage containing organic sulfur compounds such as dimethyl sulfoxide (DMSO).

Example

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Example 1]

Waste water from an electronic component manufacturing factory with the following water quality was used as raw water, and treated with the organic matter-containing waste water treatment device shown in Fig. 1 .

<Raw water quality>

COD _Cr : 1500～3000mg/L (average 2000mg/L)

T-N: 30～70mg/L (average 50mg/L)

T-P: 3.0mg/L (Ca, Mg, K, and other trace metals are added together as nutrients)

As the anaerobic biological treatment tank 1, a tank with a capacity of 10 L (cylindrical shape of φ16 cm×H60 cm) was used, the hydraulic residence time was 4.8 hours, and the treatment was performed by heating to a temperature of 35°C.

In the anaerobic biological treatment tank 1, 4L polypropylene cylindrical carrier (φ3mm×5mm) was filled, and 500mL of pellets from the wastewater treatment facility of the beer factory were put into 500mL as seed sludge, and after acclimatization for 2 months, the treated Water is introduced into the aerobic biological treatment tank 2 .

As the aerobic biological treatment tank 2, a tank with a tank capacity of 1.5 L was used, and as the biological fixed bed 4, a pore diameter: 500 μm, thickness: a sponge plate of 1 cm (apparent volume: 100 mL (100 mL of the volume of the aerobic biological treatment tank) was used. 7%)), fixed on the position where the sludge that is aerated and rolled up from the diffuser pipe 6 aeration provided at the bottom of the membrane module 5 settles.

As the membrane module 5, a hollow fiber-type MF membrane ("Microza MF RaboModule (trade name)" manufactured by Asahi Kasei Chemical Co., Ltd., made of polyvinylidene fluoride, pore diameter: 0.10 μm) was used, and it was dipped into The top of the diffuser pipe 6.

The aerobic biological treatment tank 2 starts with the activated sludge from the wastewater treatment equipment of the electronic component manufacturing factory as the seed sludge. The amount of 0.4m/d is sucked, thereby, the membrane separation treatment is performed, and on the other hand, the excess sludge is taken out at 75mL/day (SRT 20 days).

In addition, when the transmembrane pressure difference increased to 30kPa, the membrane module 5 was lifted to perform chemical cleaning (immersion in a solution of NaClO+NaOH (adjusted to pH 12) with an effective rate of 0.3% for 6 hours).

Two weeks after the start of the operation (2 weeks after the start of the operation was regarded as the operation day 0), the change in the transmembrane pressure difference was measured, and the time-dependent change in the transmembrane pressure difference is shown in FIG. 2 .

[Comparative example 1]

In Example 1, the treatment was performed in the same manner except that the biological fixed bed was not provided in the aerobic biological treatment tank 2 , and the time-dependent change of the transmembrane pressure difference is shown in FIG. 2 .

In Example 1 and Comparative Example 1, in the anaerobic biological treatment tank 1, for a COD _Cr load of 10 kg/m ³ ·day, a removal rate of around 90% was stably obtained during the test period, and the aerobic biological The COD _Cr of the treated water in the treatment tank 2 changed stably below 10 mg/L (comparative example 1: average 5.4 mg/L; Example 1: average 5.0 mg/L).

The rate of rise of the transmembrane pressure difference during the period of stable operation is 1.3 kPa/day in Comparative Example 1, and 0.54 kPa/day in Example 1. The frequency of washing the medicines is lowered to about once every 50 days in Example 1, on the other hand.

Further, when the flux during filtration is increased to 0.7m/day, in Comparative Example 1, the rate of rise of the transmembrane pressure difference rises to 2.8kPa/day, and it is necessary to wash the medicine more than once every 10 days. In contrast, in Example 1, the increase rate of the transmembrane pressure difference was small, and the cleaning frequency of about once every 50 days could be maintained.

In addition, as a result of the SS analysis of the anaerobic biologically treated water, the anaerobic biologically treated water contained 60 to 100 mg/L of SS, and the water kept flowing into the aerobic biologically treated tank 2 . As a result of measuring the particle size distribution of SS components in anaerobic treatment water and aerobic biological treatment tank sludge, fine SS components with a particle size of less than 10 μm accounted for 40% of the anaerobic biological treatment water. In the aerobic biological treatment tank sludge of Comparative Example 1, fine SS components having a particle diameter of less than 10 μm also accounted for about 10%. In contrast, in the aerobic biological treatment tank sludge of Example 1, the fine SS component with a particle size of less than 10 μm was significantly reduced to about 0.3%, which shows that in the aerobic biological treatment tank, the fine SS Components decompose and lead to improved membrane filterability.

Thus, according to the present invention, it can be seen that in the treatment combining anaerobic biological treatment and membrane separation activated sludge treatment, membrane fouling caused by fine SS components generated by anaerobic biological treatment can be reduced, and membrane cleaning can be reduced. frequency and maintain high membrane flux for operation.

Claims (4)

1. treatment unit that contains the organism draining, it has: carry out the anaerob treatment trough that anaerob is handled to containing the organism draining; To carry out the aerobe treatment trough that aerobe is handled from the effusive anaerob treating water of this anaerob treatment trough; Membrane separation plant with the aerobe treating water of this aerobe treatment trough being carried out solid-liquid separation is characterized in that,

In this aerobe treatment trough, be provided with biological fixed-bed.

2. the treatment unit that contains the organism draining according to claim 1 is characterized in that, with respect to the volume of said aerobe treatment trough, the volume of said biological fixed-bed is 1～30%.

3. the treatment unit that contains the organism draining according to claim 1 and 2 is characterized in that, said membrane separation plant is the dipped type film separating device that is immersed in the said aerobe treatment trough.

4. the treatment unit that contains the organism draining according to claim 3; It is characterized in that; Half side dipping in the said aerobe treatment trough disposes said biological fixed-bed; Another half side dipping disposes said dipped type film separating device, below said dipped type film separating device, is provided with aerator.

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