KR20060031141A - Advanced wastewater treatment apparatus by crossflow membrane - Google Patents

Abstract

In the present invention, in the advanced treatment of domestic sewage or industrial wastewater, using a circulating separator instead of the sedimentation basin used in the bioreaction process, it is possible to completely remove suspended solids and E. coli from the treated water. It relates to an advanced wastewater treatment system, the configuration of which is composed of an anaerobic tank equipped with a stirrer, an anoxic tank, an aerobic tank filled with granular carrier and supplied with air, and an internal circulation tank for supplying some treated water to an anoxic tank ( 6) in the advanced sewage / wastewater treatment apparatus,

A circulation pump and a separator are installed at the rear end of the internal circulation tank of the bioreactor, and a circulating membrane system for discharging the treated water through the circulating pump and the membrane, and the sludge in the concentrated water generated in the circulating membrane system is disposed of and anaerobic tank. Each valve for returning to the furnace is installed in a corresponding line, and includes a pressurized pump for supplying the treated water in the inner circulation tank into the circulating membrane system.

Bioreactor, Circulating Membrane, Tubular Microfiltration Membrane

Description

Advanced wastewater treatment apparatus by crossflow membrane

1 is a sewage / wastewater treatment process according to the prior art,

Figure 2 is a schematic diagram of an advanced sewage / wastewater treatment apparatus using a circulating separator of the present invention.

※ Explanation of code for main part of drawing ※

1: raw water supply pump 2: stirrer

3: anaerobic tank 4: anaerobic tank

5: aerobic tank 6: internal circulation tank

7: Separation membrane 8: Sedimentation tank

9: pressurized pump 10: circulation pump

11: internal circulation pump 12a, 12b: valve

13: blower

The present invention relates to an advanced sewage / wastewater treatment apparatus using a circulating separator. More specifically, in the advanced treatment of domestic sewage and industrial wastewater, a circulating separator is used instead of a sedimentation basin which has been used in a bioreaction process. The present invention relates to an advanced sewage / wastewater treatment system using a circulating membrane that completely removes suspended solids and coliforms from treated water.

Recently, in Korea, water quality regulation standards have been stepped up in order to preserve the water environment.In addition to the existing suspended matter (SS), biological oxygen demand (BOD), total nitrogen (TN) items, etc. In order to reduce pollution, E. coli municidal items have been added and managed since 2003.

Table 1 below shows the water quality standards for sewage treatment plants discharged.

division BOD (mg / L) COD (mg / L) SS (mg / L) T-N (mg / L) T-P (mg / L) Escherichia coli (dog / ml) Current 20 40 20 60 8 - reinforce Specific area 10 40 10 20 2 3,000 Other Area 20 40 20 60 8 3,000

Generally, biological treatment is adopted for the treatment of sewage / wastewater, which is the main reason that the treatment is stable, relatively inexpensive, and environmentally friendly. The biological treatment method is a principle of removing contaminants by metabolism of microorganisms (contaminants in sewage / wastewater are used for energy sources or cell proliferation of microorganisms). Advanced sewage treatment is a relatively new and improved biological sewage / wastewater that removes suspended solids (SS) and biological oxygen demand (BOD), as well as total nitrogen (TN) and phosphorus (TP) components, which are recognized as the major causes of red tide. Processing technology.

Currently, the advanced sewage treatment method introduced in Korea is slightly different in the process configuration, but is generally based on the A2O process or a variation thereof, and the A2O method is an organism such as anaerobic, anoxic, and aerobic tanks. It is composed of a reactor, and removes contaminants such as organic matter and total nitrogen from the bioreactor, precipitates microorganisms in the settling tank, and discharges only the supernatant.

1 is a schematic view showing an advanced sewage treatment process consisting of a conventional general bioreactor and a sedimentation basin, wherein the conventional bioreactor is an anaerobic tank (3), an anaerobic tank (4), an aerobic tank (5), an internal circulation tank (6), and a sedimentation tank. (8), the anaerobic tank (3) and the anaerobic tank (4) is mixed by the stirrer (2), the air in the aerobic tank (5) by the blower 13 to continuously inject It is composed.

In the above configuration, the raw water is introduced into the anaerobic tank 3 through the raw water supply pump 1, and in the anaerobic tank 3, organic matter is decomposed and removed by methane gas and carbon dioxide by anaerobic microorganisms of organic matter, and phosphorus accumulating bacteria It releases phosphorus in connection with organic storage. Then, the sewage having passed through the anaerobic tank 3 is supplied to the anoxic tank 4, in which the nitrous acid and nitric acid are converted to nitrogen gas and removed by the denitrification microorganism.

On the other hand, the sewage through the anoxic tank (4) is introduced into the aerobic tank (5) filled with a granular carrier, wherein organic matter is decomposed into carbon dioxide and water by aerobic microorganisms, and ammonia nitrogen is nitrified to nitrous acid or nitric acid by nitrification microorganisms. do. In addition, phosphorus accumulation bacteria are removed as phosphorus is excessively ingested and discharged as sludge as oxidative decomposition of accumulated organic matter proceeds.

In addition, the sewage having passed through the exhalation tank (5) is introduced into the internal circulation tank (6), and after lowering the dissolved oxygen content increased in the internal circulation tank (6), some are introduced into the settling tank (8) and some are for denitrification. It is conveyed to the anoxic tank 4 by the internal circulation pump 11.

The sewage flowing into the sedimentation tank (8) is subjected to solid-liquid separation by natural sedimentation by gravity in this place, and the supernatant is discharged and the precipitated sludge is anaerobic tank by the sludge conveying pump (12) to maintain the concentration of microorganisms in the bioreactor. It is returned to (3).

Meanwhile, as a related art related to advanced sewage treatment, Korean Patent Registration No. 0188878 (Name: Granular carrier for wastewater treatment using waste tires and its manufacturing method and wastewater / wastewater treatment apparatus using this granular carrier), and domestic patent registration number No.0206748 (name: high-efficiency sewage / wastewater treatment apparatus using granular carrier) and the like, their treatment method is to make a granular carrier using the waste tire and to put it in an aerobic tank to attach the microorganism to the carrier. It is a method to improve the removal efficiency of pollutants by maintaining a high concentration of. However, there has been a problem that the treatment efficiency is lowered by finally separating the treated water and microorganisms by solid-liquid separation by gravity in the sedimentation tank.

The microorganisms involved in the sewage / wastewater treatment process are broken by the temperature of the influent sewage, the hydrogen ion concentration (pH), and the presence of toxic substances. When the pin floc is formed, the specific gravity of the microbial floc decreases, so that the microfluidic floc is not completely precipitated in the sedimentation basin, and the microflux flows out with the treated water while suspended, causing deterioration of the treated water quality and serious secondary contamination by microorganisms. come.

 The present invention was invented to solve the problems caused by the conventional sedimentation tank using the solid-liquid separation by gravity sedimentation, the treatment efficiency is changed according to the shape of the microbial floc, using a circulating membrane instead of the sedimentation tank The purpose of the present invention is to provide an advanced sewage / wastewater treatment apparatus using a circulating separator that can drastically improve the efficiency of removing contaminants regardless of the shape of microorganisms by completely removing microorganisms and suspended solids.

Characteristic technical configuration of the advanced sewage / wastewater treatment apparatus using a circulating membrane of the present invention, the anaerobic tank (3), the anoxic tank (4), and the bioreactor provided with a stirrer (2) to achieve the above object, and In the advanced sewage / wastewater treatment apparatus consisting of an aerobic tank (5) filled with a granular carrier and supplied with air, and an internal circulation tank (6) for supplying a part of treated water to the anoxic tank (4),

A circulating pump system (A) for discharging the treated water through the circulating pump (10) and the separator (7) is installed at the rear end of the internal circulation tank (6) of the bioreactor. And valves 12a and 12b for discharging sludge in the concentrated water generated in the circulating membrane system A to the waste and anaerobic tank 3 are installed in the corresponding line, and the inner circulation tank 6 is provided. It consists of the structure containing the pressure pump 9 which supplies the process water in the said circulation type membrane system A. FIG.

In addition, the separator in the circulating separator system uses a tubular microfiltration membrane made of ceramic material, and the tubular microfiltration membrane uses a pore diameter of 0.1 μm.

Referring to the accompanying drawings of the advanced sewage / wastewater treatment apparatus using a circulating membrane of the present invention having the characteristics as described above in detail as follows.

Figure 2 is a schematic diagram showing an embodiment of the advanced sewage / wastewater treatment apparatus using a circulating membrane of the present invention, in the anaerobic tank (3) and an anaerobic tank (4) is mixed by the stirrer (2), the aerobic tank In 5, air is continuously injected by the blower 13.

In this configuration, raw water is introduced into the anaerobic tank (3) through the raw water supply pump (1), and in the anaerobic tank (3), organic matter is decomposed into methane gas and carbon dioxide by the anaerobic microorganisms of organic matter, and phosphorus accumulating bacteria are organic matter. Release phosphorus in connection with storage. The sewage / wastewater passing through the anaerobic tank 3 is supplied to an anaerobic tank 4, in which the nitrous acid and nitric acid are converted to nitrogen gas and removed by denitrifying microorganisms.

Then, the sewage through the anoxic tank (4) is introduced into the aerobic tank (5) filled with a granular carrier, wherein organic matter is decomposed into carbon dioxide and water by aerobic microorganisms, and ammonia nitrogen is nitrate or nitric acid by nitrification microorganisms. Nitrified. In addition, the phosphorus accumulation bacteria are removed as phosphorus is excessively ingested and discharged in the form of sludge as oxidative decomposition of accumulated organic matter proceeds.

The sewage that passed through the aerobic tank (5) is introduced into the internal circulation tank (6), where the lowered dissolved oxygen content is lowered, and some are introduced into the anoxic tank (4) by the endothermic circulation pump (11) for denitrification. The circulation pump 10 and the separation membrane 7 are installed by the pressure pump 11 and supplied to the circulation separation membrane system A for discharging and circulating the treated water.

Since the tubular microfiltration membrane 7 having a pore diameter of 0.1 μm is mounted in the circulating membrane system A, the microorganisms are discharged through the membrane by the pressure of the membrane circulation pump 10. Of course, the particulate matter can be completely removed. At this time, some of the circulating water is returned to the anaerobic tank 3 through the sludge return valve 12a in order to maintain a high concentration of microorganisms in the bioreactor, and a part of the circulating separator system A is externally provided through the sludge discharge valve 12b. To be discharged.

On the other hand, there are two types of separation membranes used in the circulating membrane system A, which are hollow fiber type and tubular type. The hollow fiber type membranes have a small diameter, which causes severe fouling of the membrane, and the membrane is broken by an external impact during operation. Loss often occurs. In this case, since the sewage is discharged through the broken hollow fiber membrane section instead of passing through the pores of the separator, the water quality may be drastically degraded. However, since the diameter of the tubular separation membrane is large and physically strong, the membrane contamination state is small, and it is hardly damaged by an external impact and thus can be stably treated. Therefore, in the present invention, a tubular separator was used.

The present invention has been described as an example of an advanced sewage / wastewater treatment system using an external circulating tubular separation membrane, and in the following, the efficiency of removing pollutants in the advanced sewage / wastewater treatment process according to the present invention and the existing treatment process is compared. In order to explain the results of the long-term experiment in the sewage treatment plant.

The experiment by the advanced sewage / wastewater treatment process of the present invention was used as an example, and the experiment by the conventional treatment process was used as a comparative example.

(Example)

In the advanced sewage treatment process using the circulating membrane system according to the present invention, the inflow flow rate is Q (1.0㎥ / hr), the internal circulation water amount is 1.5Q, the sludge conveying flow rate is 0.5Q, the excess sludge quantity is 0.05Q, the circulation water quantity is 170Q, the treated water was maintained at 0.95Q. The specifications and residence times of each bioreactor used in the present invention are shown in Table 2 below.

division Anaerobic tank Anaerobic Aerobic Internal circulation tank Residence time (HR) 1.4 2.0 2.0 0.6 Capacity (M3) 28 40 40 12

Table 3 below shows the concentration of raw water and treated water and the removal rate of pollutants for each pollutant during the operation time according to the present invention.

Item enemy Treated water % Removal pH (-) 7.13 7.45 - SS (mg / L) 103 0.7 99.3 Escherichia coli (dog / ml) 1200 48 96.0 COD (mg / L) 55.3 6.1 89.0 BOD (mg / L) 61.0 6.8 88.8 T-P (mg / L) 1.77 0.80 54.8 T-N (mg / L) 24.8 4.9 80.2

(Comparative Example)

The advanced sewage treatment process using the conventional bioreactor and sedimentation tank, the inflow flow rate is Q (1.0㎥ / hr), the internal circulating water amount is 1.5Q, the sludge return flow rate is 0.5Q, the excess sludge quantity is 0.05Q, the treated water quantity is 0.95Q Was maintained. The specifications and residence times of existing bioreactors are shown in Table 4 below.                     

division Anaerobic tank Anaerobic Aerobic Internal circulation tank Sedimentation tank Retention time (hr) 1.4 2.0 2.5 0.6 1.8 Capacity (㎥) 28 40 50 12 36

Table 5 shows the contaminant concentrations and removal rates of the raw water and the treated water during the operation time for the conventional biological treatment process.

Item enemy Treated water % Removal pH (-) 7.15 7.40 - SS (mg / L) 169 8.7 92.9 Escherichia coli (dog / ml) 6,000 1,980 67.0 COD (mg / L) 58.4 9.1 79.6 BOD (mg / L) 60.0 10.2 83.0 T-P (mg / L) 2.9 0.7 70.0 T-N (mg / L) 28.9 8.5 70.1

As a result of comparing the pollutant removal efficiency of the above two treatment process, the treatment process developed in the present invention was superior to the treatment efficiency by the conventional bioreactor, and in particular, almost 100% removal in the SS and E. coli group surface treatment was possible. It can be seen that the efficiency is significantly improved.

As described above, the sewage / wastewater treatment system using the circulating separator according to the present invention uses the circulating membrane system instead of the sedimentation basin in the advanced sewage treatment process using the conventional bioreactor, regardless of the shape of the microbial floc (SS). Of course, E. coli was also able to obtain almost 100% removable effect.

Claims (4)

The bioreactor supplies an anaerobic tank (3) equipped with a stirrer (2), an anoxic tank (4), an aerobic tank (5) filled with air, and a granular carrier, and a portion of treated water to the anoxic tank (4). In the sewage / wastewater advanced treatment device composed of an internal circulation tank (6), A circulating pump system (A) for discharging the treated water through the circulating pump (10) and the separator (7) is installed at the rear end of the internal circulation tank (6) of the bioreactor. And valves 12a and 12b for discharging sludge in the concentrated water generated in the circulating membrane system A to the waste and anaerobic tank 3 are installed in the corresponding line, and the inner circulation tank 6 is provided. An advanced sewage / wastewater treatment apparatus using a circulating separator, characterized in that it comprises a pressurized pump (9) for supplying the treated water therein into the circulating separator system (A). The apparatus of claim 1, wherein the separator in the circulating separator system is a tubular microfiltration membrane. 3. The advanced sewage / wastewater treatment system using a circulating separator according to claim 2, wherein the tubular microfiltration membrane has a pore size of 0.1 µm. 3. The advanced sewage / wastewater treatment system using a circulating separator according to claim 2, wherein the tubular microfiltration membrane is made of ceramic.

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