JP2021533994A - Method for improving film formation efficiency of filler in water treatment reactor - Google Patents

Abstract

The present invention discloses a method for improving the film formation efficiency of a filler in a water treatment reactor using the following implementation steps, seeds activated sludge in a reactor operated in a sequential batch system, and has a hydraulic residence time. It is 4 hours and consists of water supply 5 min, aeration 108 to 111 min, static sedimentation 2 to 5 min, and water discharge 2 min per cycle, where the organic load of the water supply is 6 to 12 g / (L · d) and the air flow velocity. Is 1.6 to 2.4 cm / s, and when the reactor is operated from the 2nd to the 4th day, aerobic particle sludge containing a large amount of film-forming microorganisms is formed in the reactor, and the reaction occurs at this time. The filler is put into the reactor, and the film formation is completed 2 to 5 days after the filler is put in the reactor. Compared with other film forming methods, the film forming method of the present invention does not require administration of expensive special microorganisms and substrates, and the film forming cost is low. The running cost is reduced, the film forming time of the filler is shortened to 2 to 5 days, and the film forming efficiency of the biological film method is greatly improved. [Selection diagram] Fig. 3

Description

The present invention relates to a method for improving the film formation efficiency of a filler in a water treatment reactor, and relates to a technical field of sewage treatment.

Sewage biological treatment technology is roughly divided into activated sludge method and biological membrane method. Compared to the activated sludge method, the biomembrane method has many advantages such as high microbial diversity, abundant biomass, low sludge production, impact resistance, easy management, and low running cost. Has. Due to these advantages, the biological membrane method is widely used in the field of sewage treatment. The biofilm is formed by the adhesion of microorganisms to the surface of the filler and growth. When the biofilm grows to a certain thickness, mass transfer by oxygen gas is restricted, and the outer layer of the biofilm becomes aerobic and the inner layer becomes anaerobic. Biofilm systems generally have high microbial diversity, as biofilm microorganisms consist of aerobic microorganisms, euphoric microorganisms and anaerobic microorganisms in order from the outside to the inside. When sewage flows on the surface of the biological membrane, pollutants in the sewage are adsorbed on the surface layer of the biological membrane and migrate to the inner layer, and various pollutants are removed during mass transfer. When the biofilm grows to a certain thickness, oxygen and nutrients are not transmitted to the inner layer, and the biofilm in the inner layer deteriorates and peels off. The filler surface then continues to grow new biofilms, allowing the system to operate stably for extended periods of time.

Although biomembrane technology has been rapidly developing in recent years, it is limited by many factors, and low membrane formation efficiency is one of the important limiting factors. In the conventional film forming method, activated sludge from the aeration pond of the sewage treatment plant is used as infusion sludge, which is once steamed, the mixture of activated sludge and wastewater in the biological membrane reactor is exhausted, and the wastewater to be treated is charged. Film formation is performed. In the conventional film formation method, the start cycle of film formation requires at least 15 to 30 days, and even more, which significantly increases the running cost of the system. In recent years, researchers have proposed several new film-forming methods to improve film-forming efficiency. The patent "Method for Improving Biofilm Formation Performance of Suspension Fillers" (Application No. 200710105788.2) enhances the adsorption capacity between the filler and microorganisms by adding magnetic powder or ferromagnetic fine particles. , Promotes film formation. Many studies have been conducted to improve the film formation efficiency by a method of administering a functional microorganism. All of these methods can improve the film formation efficiency to some extent, but in reality, it is difficult to spread them on a large scale due to restrictions on factors such as cost, safety, and complicated operation. Therefore, in the biofilm sewage treatment process, it is important to study a rapid, simple and efficient membrane forming method.

The present invention can obtain a microbial community with strong adhesive force by optimizing the acclimation conditions, and at the same time, by coordinating the conditions that can promote the rapid growth of the microbial membrane, the membrane of the filler in the reactor. Provided is a method for improving the film forming efficiency of a filler in a water treatment reactor, which can significantly improve the forming efficiency.

In order to solve the above technical problems, the present invention employs the following technical means.
It is a method for improving the film formation efficiency of a filler in a water treatment reactor using the following implementation steps, in which activated sludge is sown in a reactor operated in a sequential batch system, and the aeration residence time is 4 hours. Each cycle consists of 5 min of water supply, 108 to 111 min of aeration, 2 to 5 min of static sedimentation, and 2 min of water discharge, where the organic load of water supply is 6 to 12 g / (L · d) and the air flow velocity is 1.6. It is ~ 2.4 cm / s, and when the reactor is operated from the 2nd to the 4th day, aerobic particle sludge containing a large amount of film-forming microorganisms is formed in the reactor, and at this time, a filler is formed in the reactor. The film formation is completed 2 to 5 days after the filler is put into the reactor.

Here, the reactor has a cylindrical structure and has an aspect ratio of 20.

Here, the activated sludge to be inoculated is the activated sludge in the aeration pond of the sewage treatment plant, and the sludge concentration is 3000 to 8000 mg / L.

Here, the organic carbon source in the water supply to the reactor is sodium acetate, and the concentration of sodium acetate is 1000-2000 mg / L.

Here, the water supply to the reaction vessel, in _addition to organic carbon _{sources, NH 4 Cl (50mg / L} ), K 2 HPO 4 (10mg / L), CaCl 2 2H 2 O (30mg / L), MgSO 4 7H _{2 O (25mg / L),} FeSO 4 7H 2 O (20mg / L), H 3 BO 3 (0.05mg / L), ZnCl 2 (0.05mg / L), CuCl 2 (0.03mg / L) _{, MnSO 4 H 2 O (0.05mg} / L), (NH 4) 6 Mo 7 O 24 4H 2 O (0.05mg / L), AlCl 3 (0.05mg / L), CoCl 2 6H 2 O ( It further contains 0.05 mg / L) and NiCl ₂ (0.05 mg / L).

The apparatus adopted in the present invention is a cylindrical reactor (aspect ratio 20), adopts aeration pond sludge from an urban sewage treatment plant as infusion sludge, has a short settling time (2 to 5 min), and has a high organic load (6 to 12 g). / (L · d)), a large air flow velocity (1.6 to 2.4 cm / s), and a hydraulic residence time of 4 hours. The reactors are operated sequentially in batch mode, and each cycle consists of 5 min of water supply, 108 to 111 min of aeration, 2 to 5 min of standing still, and 2 min of water discharge. The volume exchange ratio per cycle (water supply and drainage) is 50 to 70%. Under these conditions, a large amount of microorganisms suitable for growth by the biofilm method can be concentrated. A large amount of fine sludge particles (aerobic sludge particles) are observed in the operation of the reactor on the 2nd to 4th days, and at this time, the filler is charged into the reactor. The filling rate of the filler into the reactor is 50% or less. Membrane formation is completed 2 to 5 days after the filler is added. The membrane forming method of the present invention does not require a special inoculum or substrate, enables rapid membrane formation of the filler with a simple operation, and significantly reduces the membrane formation and start time of the sewage treatment system by the biological membrane method. Can be shortened.

The present invention has the following advantageous effects as compared with the prior art.
Compared with other film forming methods, the film forming method of the present invention does not require administration of expensive special microorganisms and substrates, and the film forming cost is low. The present invention realizes film formation on the filler surface by utilizing aerobic sludge particles, reduces running costs, shortens the film formation time of the filler to 2 to 5 days, and forms a film by the biological film method. Greatly improve efficiency. At the same time, the microbial membrane formed on the filler is difficult to peel off. The apparatus used in the film forming method of the present invention has a simple structure, a low running cost, and a high film forming efficiency.

It is a figure which shows the filler which formed the film for 15 days using the conventional method. It is a figure which shows the filler which formed the film on the 2nd day using the film formation method of Example 1 of this invention. It is a figure which shows the structure of the experimental apparatus used for the film formation method of this invention.

Hereinafter, the technical means of the present invention will be further described with reference to the drawings and specific examples.

Example 1
The reactor adopts a cylindrical structure, the reaction area has a diameter of 5 cm and a height of 100 cm, and the volume of the reaction area is 2 L. The hydraulic residence time of the sequential batch reactor is 4 hours and the volume exchange ratio per cycle is 50%. One cycle consists of water supply 5 min, aeration 111 min, static sedimentation 2 min, and water discharge 2 min. The organic load is 6 g / (L · d) and the air flow rate is 2.4 cm / s (the air flow rate in the reactor is controlled by aeration). The inoculated sludge of the reactor is collected from the aeration pond of the urban sewage treatment plant, and the initial sludge concentration of the reactor is 6000 mg / L. Sodium acetate is used as the organic carbon source, and the COD concentration is 1000 mg / L. The reactor is operated at room temperature to maintain the pH at 6.5-8.5. As shown in FIG. 2, the filler was charged on the second day when the reactor was operated, the filling factor of the filler was 20%, and the biofilm was charged on the second day after the filler was charged into the reactor. The thickness reaches 2 mm.

Example 2
The reactor adopts a cylindrical structure, the reaction area has a diameter of 5 cm and a height of 100 cm, and the volume of the reaction area is 2 L. The hydraulic residence time of the sequential batch reactor is 4 hours and the volume exchange ratio per cycle is 50%. One cycle consists of water supply 5 min, aeration 111 min, static sedimentation 2 min, and water discharge 2 min. The organic load is 12 g / (L · d) and the air flow velocity is 2.4 cm / s. The inoculated sludge of the reactor is collected from the aeration pond of the urban sewage treatment plant, and the initial sludge concentration of the reactor is 6000 mg / L. Sodium acetate is used as the organic carbon source, and the COD concentration is 2000 mg / L. The reactor is operated at room temperature to maintain the pH at 6.5-8.5. The filler is charged on the second day when the reactor is operated, the filling rate of the filler is 20%, and the thickness of the biofilm reaches 2 mm on the second day after the filler is charged into the reactor. .. As compared with Example 1, it can be seen that the thickness of the biofilm is not so different from the case where the organic load is 12 g / (L · d), so that even if the organic load is 6 g / (L · d). , High-speed film formation can be realized by this method.

Comparative Example 1
In this experiment, a membrane is formed using a conventional method, and a fluidized bed biofilm reactor (MBBR) is operated using a membrane-forming filler. First, the filler is put into the activated sludge and steamed for 48 hours, the mixture of the activated sludge and the wastewater in the MBBR reactor is exhausted, and the wastewater to be treated is put into it. The hydraulic residence time of the MBBR reactor is 6 hours. Sodium acetate is used as an organic carbon source, and the COD concentration is 300 mg / L. After the filler was added to the activated sludge and steamed for 48 hours, there was almost no adhesion of the biofilm, and the biofilm appeared after 15 days of operation, but as shown in FIG. 1, the thickness of the biofilm was less than 1 mm. It can be seen that the film forming efficiency is significantly lower than that of the film forming method of the present invention.

The film forming method of the present invention employs a large aspect, a short settling time, a high organic load, and a large air flow velocity during microbial acclimation. This condition is suitable for the formation of aerobic particle sludge containing a large amount of film-forming microorganisms. In aerobic particle sludge, a large amount of film-forming microorganisms are condensed in a reactor, and when a filler is added at the initial stage of formation of aerobic particle sludge, a biological film can be rapidly formed on the surface of the filler. At the same time, the microbial community acclimatized under these conditions has a strong adhesive force and is a filler (the filler used in the present invention is 50 to 60 parts by mass of polypropylene, 20 to 30 parts of epoxy resin and 5 to 10 parts of starch. The filler has the advantages of having a large specific surface area, a high void ratio, and an advantage in the adhesion of microorganisms, and is suitable for the adhesion and growth of microorganisms. The film on the agent is difficult to peel off. Further, due to the high organic load, the microorganisms adhering to the surface of the filler are rapidly grown, which is advantageous for the rapid formation of the biofilm, and further improves the film formation efficiency of the filler.

FIG. 3 shows an experimental device used in the film forming method of the present invention. The water tank contains water containing sodium acetate at a constant concentration as a carbon source for growing microorganisms, this water is supplied into the reactor by a perturbation pump, and the air flow velocity in the reactor is controlled by an aeration pump. Prepare a water supply with a high organic load (6-12 g / (L · d)). This water supply acts with the activated sludge inoculated into the reactor to form aerobic particle sludge containing a large amount of film-forming microbial particles, and immediately after the formation of this aerobic particle sludge, a filler is charged into the reaction tank. , A biofilm is formed on the surface of the filler immediately after the filler is added. Reactor drainage is controlled by a solenoid valve to enter the wastewater tank.

(Additional note)
(Appendix 1)
A method for improving the film formation efficiency of a filler in a water treatment reactor using the following implementation steps.
Activated sludge is sown in a reactor that operates in a sequential batch system, and the hydraulic residence time is 4 hours. Here, the organic load of the water supply is 6 to 12 g / (L · d), the air flow velocity is 1.6 to 2.4 cm / s, and the air flow velocity is 1.6 to 2.4 cm / s.
When the reactor was operated for 2 to 4 days, aerobic particle sludge containing a large amount of film-forming microorganisms was formed in the reactor, and at this time, a filler was added to the reactor.
It is characterized in that the film formation is completed 2 to 5 days after the filler is placed in the reactor.
A method for improving the film formation efficiency of a filler in a water treatment reactor.

(Appendix 2)
The reactor has a tubular structure and has an aspect ratio of 20.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to Appendix 1.

(Appendix 3)
The activated sludge to be inoculated into the reactor is the activated sludge in the aeration pond of the sewage treatment plant, and the sludge concentration is 3000 to 8000 mg / L.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to Appendix 1.

(Appendix 4)
The volume exchange ratio per cycle is 50 to 70%.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to Appendix 1.

(Appendix 5)
The temperature inside the reactor is 15 to 30 ° C., and the pH is 6.5 to 8.5.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to Appendix 1.

(Appendix 6)
Supply of water to the reaction vessel, in _addition to organic carbon _{sources, 50mg / LNH 4 Cl, 10mg} / LK 2 HPO 4, 30mg / LCaCl 2 2H 2 O, 25mg / LMgSO 4 7H 2 O, 20mg / LFeSO 4 7H 2 _{O, 0.05mg / LH 3 BO 3} , 0.05mg / LZnCl 2, 0.03mg / LCuCl 2, 0.05mg / LMnSO 4 H 2 O, 0.05mg / L (NH 4) 6 Mo 7 O 24 4H _{2 O,} 0.05mg / LAlCl _3, further characterized in that it contains 0.05mg / LCoCl ₂ 6H ₂ O and 0.05mg / LNiCl _2,
The method for improving the film formation efficiency of a filler in the water treatment reactor according to Appendix 1.

(Appendix 7)
The reactor is characterized in that the filling rate of the filler is 50% or less.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to Appendix 1.

(Appendix 8)
The organic carbon source in the water supplied to the reactor is sodium acetate, and the concentration of sodium acetate is 1000-2000 mg / L.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to Appendix 6.

Claims (8)

A method for improving the film formation efficiency of a filler in a water treatment reactor using the following implementation steps.
Activated sludge is sown in a reactor that operates in a sequential batch system, and the hydraulic residence time is 4 hours. Here, the organic load of the water supply is 6 to 12 g / (L · d), the air flow velocity is 1.6 to 2.4 cm / s, and the air flow velocity is 1.6 to 2.4 cm / s.
When the reactor was operated for 2 to 4 days, aerobic particle sludge containing a large amount of film-forming microorganisms was formed in the reactor, and at this time, a filler was added to the reactor.
It is characterized in that the film formation is completed 2 to 5 days after the filler is placed in the reactor.
A method for improving the film formation efficiency of a filler in a water treatment reactor. The reactor has a tubular structure and has an aspect ratio of 20.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to claim 1. The activated sludge to be inoculated into the reactor is the activated sludge in the aeration pond of the sewage treatment plant, and the sludge concentration is 3000 to 8000 mg / L.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to claim 1. The volume exchange ratio per cycle is 50 to 70%.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to claim 1. The temperature inside the reactor is 15 to 30 ° C., and the pH is 6.5 to 8.5.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to claim 1. Supply of water to the reaction vessel, in _addition to organic carbon _{sources, 50mg / LNH 4 Cl, 10mg} / LK 2 HPO 4, 30mg / LCaCl 2 2H 2 O, 25mg / LMgSO 4 7H 2 O, 20mg / LFeSO 4 7H 2 _{O, 0.05mg / LH 3 BO 3} , 0.05mg / LZnCl 2, 0.03mg / LCuCl 2, 0.05mg / LMnSO 4 H 2 O, 0.05mg / L (NH 4) 6 Mo 7 O 24 4H _{2 O,} 0.05mg / LAlCl _3, further characterized in that it contains 0.05mg / LCoCl ₂ 6H ₂ O and 0.05mg / LNiCl _2,
The method for improving the film formation efficiency of a filler in the water treatment reactor according to claim 1. The reactor is characterized in that the filling rate of the filler is 50% or less.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to claim 1. The organic carbon source in the water supplied to the reactor is sodium acetate, and the concentration of sodium acetate is 1000-2000 mg / L.
The method for improving the film formation efficiency of a filler in the water treatment reactor according to claim 6.

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