KR0153211B1 - Method and equipment for sewage treatment - Google Patents

Abstract

The present invention is a sewage treatment method and apparatus for treating various concentrations of BOD, nitrogen and phosphorus in existing, newly established and expanded sewage treatment plants using biological nitrogen and phosphorus simultaneous removal process using media and microorganisms in anaerobic and anaerobic tanks. Filling of the aeration tank to prevent the short circuit of the mixture of the aeration and the aeration tank and the aeration tank to maximize the anaerobic and anaerobic reaction with smooth mixing with the sewage, and to fill the media to increase the nitrification and dust removal efficiency And the like.

Description

Sewage Treatment Method and Device

1 is a schematic diagram showing a sewage treatment method of the present invention.

2 is a view showing a reactor and a reactor outlet of the sewage treatment apparatus of the present invention.

Figure 3 is a cross-sectional view showing the filter medium filled portion of the sewage treatment apparatus of the present invention

* Explanation of symbols for main parts of the drawings

1: wear 2: anaerobic tank

3: anaerobic tank 4: abandon tank

5: filter medium filling unit 6: settling tank

7: Internal circulation facility 8: Sludge conveying facility

9: Storage tank 11, 12, 13: Outflow part

14, 15: Screen 16: Media

The present invention relates to a sewage treatment method and apparatus capable of simultaneously treating nitrogen and phosphorus in a low concentration of organic matter in sewage by integrating microorganisms in a filter medium.

Organic and nitrogen and phosphorus treatment method is presented in US Patent No. 4,867,883, but the treatment method is complicated and difficult to implement.

The purpose of the present invention is to simply change the facilities of the existing sewage treatment plant to remove the above disadvantages, to remove nitrogen and phosphorus in the sewage that is difficult to treat at the same time, and to resist the load fluctuation of organic matter and nitrogen and phosphorus, It is an object of the present invention to provide a sewage treatment method and apparatus which are continuously treated while passing through a reaction tank in which superphosphate-depleting microorganisms exist.

The present invention is described below with reference to the accompanying drawings.

The sewage treatment method and apparatus of the present invention are installed in the anaerobic tank and anoxic outlet to maximize the environment of the anaerobic tank having anaerobic microorganisms and the anoxic tank having denitrification microorganisms, and the aeration tank outlet to increase the efficiency of BOD removal nitric acid and phosphorus absorption. In order to increase the removal efficiency of nitrification and denitrification reaction and phosphorus absorption reaction, a media filling unit incorporating high concentration of microorganisms is installed to reduce the load of nitrate nitrogen transferred during internal conveyance from the aeration tank to reduce the pump cost of the internal circulation facility. To save money.

Therefore, the sewage treatment method and apparatus of the present invention, first, by installing the anaerobic tank outlet portion in the bottom of the bottom to facilitate the contact between the microorganism and the sewage and to prevent the short circuit phenomenon (Short Circuit) during the outflow after the reaction, and also maintain the anaerobic state Can increase the activity of microorganisms

Second, is it possible to increase the denitrification efficiency of nitrate nitrogen by installing the outlet part of the anoxic tank in the lower part of the tank?

Third, is it possible to reduce the short-circuit phenomenon of the mixed liquid by installing the outlet portions of each stage of the aeration tank alternately left and right and up and down?

Fourth, the media filled in the aeration tank can play a role of enhancing nitrification and denitrification efficiency. High concentrations of microorganisms can be accumulated in the media, which can help the inside of the media to be denitrified to the anaerobic section, and promote the nitrification to the aerobic section. Find out if there are any.

The present invention is described below with reference to the accompanying drawings.

The sewage treatment apparatus of the present invention constitutes a treatment system as shown in FIG. 1 to treat the primary sedimentation effluent in the actual sewage treatment plant. Reactor and post-treatment facilities required for the present invention comprises a weir (1), anaerobic tank (2), anoxic tank (3), aeration tank (4), filter medium (5) and settling tank (6), etc. Sludge conveying facilities (8) etc. conveyed from a settling tank are installed for denitrification.

Sewage used in the present invention is the primary sedimentation effluent of the actual sewage treatment plant they are introduced into the weir (1). In order to make the flow of the reaction tanks (2) to (5) a natural flow type, the position of the weir is installed to be higher than the reaction tank. On the other hand, the sewage from the weir (3) is introduced into the lower part of the anaerobic tank (2) by the natural discharge, and the dephosphorus microorganisms are released from the inside of the tank as a source of organic matter in the sewage to the extracellular. After the reaction is completed, the mixed liquid is introduced into the anoxic tank (3) in the lower part of the bottom, in order to facilitate the denitrification reaction is installed in the lower portion of the reaction tank has a form that flows into the top of the aeration tank (4) introduced from below.

In the aeration tank (4), BOD, SS removal, nitrification of ammonia nitrogen and intracellular absorption of phosphorus occur simultaneously. The filter filling unit 5 increases the nitrification and denitrification efficiency by using a high concentration of microorganisms accumulated in the filter medium, thereby reducing the pump capacity of the internal circulating facility 7 of nitrate nitrogen and improving phosphorus absorption efficiency to improve phosphorus removal rate.

A certain amount of sludge in the settling tank (6) is to be transferred to the anaerobic tank (2) using a conveying facility (8).

This facility is a process that makes it possible to process nitrogen and phosphorus in sewage by simple modification of aeration tank and installation of internal circulation facility for nitrogen and phosphorus that are difficult to process by standard activated sludge method currently operated in domestic sewage treatment plant. It is designed and manufactured by the method that can be applied to new and expanded sewage treatment plants.

The capacity of the reactor is 2.5m ³ (0.6m S3.6m S1.16m), the hydraulic residence time (hereinafter: HRT) of the aeration tank is 6 hours, the daily sewage treatment is 10m3 / day, and the F / M ratio (F, M , R) is 0.1 to 0.25 kg BOD / kg MLSS, d, organic volumetric loading rate (O, L, R,) is 0.3 to 0.5 kg BOD / M ³ , d.

Referring to FIG. 2, the introduced sewage is introduced into the anaerobic tank (2), and ortho-P is released out of the microbial cells by phosphorus removing microorganisms as a source of organic matter under complete anaerobic conditions, and the mixed solution containing the same is anaerobic tank. It flows into the anaerobic tank 3 through the outflow part 11. The anaerobic tank outlet 11 is designed to prevent the short circuit phenomenon in the case of complete anaerobic conditions and the outflow of the mixed liquid.

Meanwhile, in order to induce an effective denitrification reaction, the stirrer is mixed at a low speed at the bottom of the reactor at 30 RPM to reduce nitrogen by reducing the nitrate nitrogen circulated in the aeration tank to nitrogen gas. The oxygen-free tank outlet 12 is manufactured in a form that can prevent the phenomenon by the composition of the denitrification conditions and the shoes of the mixed liquid. The filter filling unit (5) can increase the nitrification and denitrification reaction by about 10 to 30% by filling the filter and reduce the pump installation cost and increase the concentration of nitrate nitrogen by reducing the circulation amount of the circulating nitrate nitrogen. As a result, maximum denitrification can be induced during denitrification.

On the other hand, the total volume of the reactor was 2.5 m ³ and the anaerobic tank (2), anoxic tank (3) and aeration tank (4) were 420L, respectively, and the short-circuit phenomenon of organic matter was achieved while making a complete anaerobic condition with a residence time of about 1 hr. An outlet 11 of 10 cm S100 cm S1180 cm is made in the anaerobic tank 2 for prevention. In addition, while the mixed solution introduced into the aeration tank 4 has a residence time of 4 hours, phosphorus released from the anaerobic tank 2 is absorbed into the cells of the microorganism under aerobic conditions, and thus a phosphorus removal mechanism occurs.

At this time, when the mixed solution is passed from the first aeration tank (4) to the next aeration tank (4), in order to prevent the smooth contact and short circuit phenomenon of microorganisms and organic matter, the outlet portion 13 of the first aeration tank is made at the bottom right of 25cm S 40cm. The second aeration tank (4) is the same size in the center of the left and the third aeration tank (4) was installed in the lower right corner of the same size. To increase the nitrification and denitrification efficiency, the filled media is 5 cm × 5 cm × 5 cm and fills 15% of the total volume of the reactor to integrate microorganisms in the media at a high concentration.

Referring to FIG. 3, the filter filling unit 5 designed to increase nitrogen and phosphorus removal efficiency was filled with a filter medium of size 5cm S5cm S 5cm 16 filled with 15% of the volume of the reactor 420L, and the filter medium was a polyurethane foam. It has a foam of 98% porosity and a specific surface area of 20m ² / m ³ . On the other hand, in order to prevent the filter medium (16) contained in the filter medium (5) from being lost to the left and right aeration tank (4), the screens (14) and (15) having a cross section of 0.5 cm S0.5 cm are inlet and outlet. Install on each.

EXAMPLE

(1) Device name: DNR PROCESS-1 (Daewoo Nutrient Removal Process) -1

(2) Applicable sewage treatment plant: Golpocheon sewage treatment plant; Bucheon-si, Gyeonggi-do

(3) Applicable Sewage: Primary sedimentation effluent

(4) Scale: (reactor)

Cross Section (60cm S60cm S60EA): 21600CM ²

Height: 1160cm

Volume: 2.5 m ³

Material: Acrylic Plate

(5) Operation Period: 1994.2.-1994.12.

(6) How to operate

In order to evaluate the efficiency of the sewage treatment apparatus of the present invention, an experimental experiment was conducted using a primary sedimentation effluent in a representative Gopocheon sewage treatment plant in a domestic sewage treatment plant. After seeding the return water and sludge in the aeration tank of the actual sewage treatment plant in the reactors (2) to (5), leave the adaptor at HRT 20 hr (3.3day) for about 10 days before initial start-up. When the operation starts and the BOD removal rate is over 80%, the inflow sewage is gradually increased to normalize the operation to 1 HRT 6hr after about 50 days after the operation starts.

The raw sewage flowing into the weir (1) is allowed to flow into the anaerobic tank by natural flow. The sewage flow into the anaerobic tank (2) was adjusted according to the operating conditions based on the analysis data table 1, table 2. Growth indicators of anaerobic microorganisms were based on the release rate of phosphorus in the anaerobic tank, and the nitric acid nitrogen mixture from the aeration tank end to the anaerobic tank (3) for denitrification at the time when the nitrifier was active and the nitrification rate increased in the aeration tank (4). Let internal circulation.

In the anaerobic tank (2) in the normal state, phosphorus is released into the cells of microorganisms as a source of organic matter, and in the anoxic tank (3), denitrification reaction of nitrogen nitrate takes place in the anaerobic tank (2) and the remaining organic matter is caused.

Phosphorus released from the anaerobic tank (2) is absorbed into the cells of the dephosphorus bacteria by using dissolved oxygen in the aeration tank (4). The aeration tank (4) maintained dissolved oxygen (DO) at about 2.5 to 3.5 mg / L, similar to the aeration tank conditions in the sewage treatment plant, and in this state, BOD, organic matter removal, nitrification of ammonia nitrogen, Phosphorus intracellular absorption occurs.

In addition, the filter filling unit 5 blows air only to the extent that the filter medium 6 does not sink so that a high concentration of microorganisms can be quantitated into the filter medium.

The final treated water is temporarily stored in the storage tank (9) and automatically flowed out by the level sensor.

All of the above reactors and machinery were designed and constructed to be automatically controlled by the central control unit.

After seeding 0.4 m ³ of the microorganisms in the treatment plant return sludge and the aeration tank in the reaction tank of the sewage treatment apparatus of the present invention, the adaptor was placed for about 10 days before the initial test run, and the operation was started with HRT 20hr (3.3day), and 80% or more. Increasing inflow sewage gradually increased while maintaining the BOD recovery rate. After the operation started at about 50 days after the lapse of a target inlet sewage water amount (2.5m ³⁾ then it gave the inlet to begin operation for nitrate bovine denitrification 60 with a non-200% in the circulation since the final target in the normal state That was reduced by 80%. Internal circulation was made from the aeration tank (4) to the anaerobic tank (3). Increasing the amount of influent sewage increased the nitrification rate by more than 90%, and the TN was more than 70% and the TP was more than 87%.

The pH of the influent was 6.4-7.3 and the pH of the effluent after treatment was stable at about 7.0-7.3 and the water temperature in the reactor was maintained at 15 ~ 28 ℃. The effect of phosphorus removal rate on temperature was not significant, but the effect of nitrification rate on the non-proliferative rate μmax of nitrifying microorganisms was in the form of μ = max (T-Tref) and the saturation constant Ks, l) was found to be 0.04e ^{0.11S (T-15)} Ks, l.

The sewage treatment apparatus of the present invention removes the nitrogen and phosphorus because the cost required for the simple change (a diaphragm installation) of the aeration tank (4) and the installation of a pump for internal circulation of nitrate nitrogen is insignificant considering the change cost of the existing facility. It is very economical compared to the cost of additional reactors, pumps and chemicals required for the installation.

The outlets 11 and 12 installed in the anaerobic tank (2) and the anoxic tank (3) inside the reactor are formed under complete anaerobic and anoxic conditions so that phosphorus release of effective phosphorus removing microorganisms and denitrification of nitrate nitrogen occur. Therefore, it is possible to treat nitrogen and phosphorus which is difficult to treat in low concentration sewage such as domestic. In addition, the outlet portion 13 installed in each stage of the aeration tank 4 has an effect of preventing a short circuit phenomenon that may occur in the existing nitrogen and phosphorus removal process. On the other hand, the existing nitrogen and phosphorus removal process has a number of problems, such as the sludge generated after the addition of the reaction tank installation and chemical injection rate treatment is relatively excellent in the present invention. In addition, the filter medium filled in the filter medium (5) can increase the nitrogen and phosphorus removal efficiency of the anaerobic-aerobic process currently developed by about 10 to 30%, and the aeration tank due to the load shock generated in the existing sewage treatment plant and Sludge swelling of the sedimentation tank can be reduced, which is very effective in the operation of the process.

Sewage treatment plant applicable to the sewage treatment method and apparatus of the present invention is a large-scale (more than 5000m3 / d) sewage treatment plant, BOD <70 mg / L low concentration sewage treatment plant, sewage treatment plant where sludge swelling frequently occurs, BOD> 140 mg / It is a high concentration sewage treatment plant of L, a sewage treatment plant with high nitrogen and phosphorus concentration, a sewage treatment plant with high BOD load fluctuations, and a small packaged wastewater treatment plant.

Claims (3)

The sewage is introduced into the anaerobic tank (2) to release ortho-phosphorus by the phosphorus-removing microorganism, and then inflow into the anoxic tank (3) and the aeration tank (4) in turn, and then into the filter filling unit (5) to carry out nitrification and denitrification. 10 to 30% by increasing the circulating amount of nitrate nitrogen circulated internally, the sewage treatment method characterized in that to increase the concentration of nitrate nitrogen to induce maximum denitrification reaction. Equipped with a weir (1), anaerobic tank (2), anoxic tank (3), aeration tank (4), filter medium (5) and sedimentation tank (6), and has an internal circulation facility (7) and a sludge conveying facility (8), The filter medium filling part 5 is filled with a filter medium 14, and the filter medium filling part 5 is configured to install screens 14 and 15 to prevent the filter medium 16 from being lost. . The sewage treatment apparatus according to claim 2, wherein the media (16) has a size of 5 cm x 5 cm x 5 cm and has a porosity of 98% and a specific surface area of 20 m ² / m ³ in the form of polyurethane foam.