KR100904214B1 - Improved secondary sedimentation basins of biological sewage and waste water treatment plant. - Google Patents

Abstract

The present invention relates to a rectangular secondary sedimentation basin of a wastewater treatment plant under biological treatment.

An object of the present invention is to provide an improved rectangular secondary sedimentation basin which reduces the influence of density flow generated in a rectangular secondary sedimentation cell of a wastewater treatment plant, thereby increasing sedimentation efficiency and increasing scum removal efficiency on the water surface.

In order to achieve the object of the present invention, in the rear end of the aerobic reaction tank is installed on the upstream downward weir and the degassing tank, the equal flow pipe and the hole rectification wall is installed in the sedimentation basin inlet and wastewater flowing into the sedimentation basin It was introduced evenly, and a supernatant water collecting device was installed from the front side to the rear side of the sedimentation basin near both wall surfaces of the sedimentation basin.

The sludge collector is installed long from the front of the eutectic wall to near the scum removal channel installed on the rear wall of the sedimentation basin. The sludge at the bottom of the sedimentation basin is transferred to the sludge hopper at the front side and the scum on the water is transferred to the scum removal channel behind the sedimentation basin. It was made.

Secondary sedimentation basin of the improved biological treatment plant of the present invention does not break the flog of the mixed liquor, the inflow flow rate is equal, and the supernatant water is collected near both sidewalls of the sedimentation basin, the influence of density flow is small, the sedimentation efficiency is good, The scum removal rate is high because all scums in the phase can be removed, so that the quality of the supernatant water of the sedimentation basin is improved and the surface of the sedimentation basin is clean.

Description

Improved secondary sedimentation basins of biological sewage and waste water treatment plant.

1 is a longitudinal sectional view showing a configuration state of the present invention.

2 is a plan view showing a configuration state of the present invention;

Figure 3 is a cross-sectional view showing a configuration state of the present invention

4 is a detailed view of the supernatant water collecting device and scum removing channel of the present invention.

5 is a detailed view of the scum removing channel of the present invention.

Figure 6 is a detailed view from the rear end of the aerobic reactor of the present invention to the sedimentation basin inlet.

7 is an explanatory view of an even distribution pipe of the present invention.

8 is a longitudinal sectional view showing the shape of a typical density flow.

Explanation of symbols for important parts of the drawings

Monthly Weir 1-1. Weir plate 1-2. Set screw

2. Degassing tank

3. pipe diffuser tube

4. Raceway

5. Adjustable Sluice

6. Bulkhead

7. Equal Distribution Tube 7-1. Distribution hole

8. Slope

9. Perforated Commutation Wall 9-1. Stiffener 9-2. Commutation hole

10. Settler wall

11. Super water collecting device 11-1. Non catchment 11-11. Orifice hole

12. Scum prevention plate

13. Supernatant drainage

14. Supernatant drainage pipe

15. With scum removal water 15-1. Weir Plate 15-2. Through hole

15-3. 15-4. Set screw

16. Scum exhaust pipe

17. Sludge Collector 17-1. Flight 17-2. Information rail 17-3. Collector chain

18. Settler Bottom

19. Scum valve

20. Sludge Drawing Pipe

end. Aerobic reactor; Sedimentation c. A joint sphere; Sedimentation Slab

hemp. Aerobic Slab Bar. Sludge hopper

The present invention relates to a rectangular secondary sedimentation basin of a wastewater treatment plant under biological treatment.

The conventional sedimentary secondary sedimentation basin of the wastewater treatment plant is uneven in the structure of the inlet part, and the floc in the mixed liquor may be broken or drift may occur, resulting in poor sedimentation.

Also, in case of downtime due to damage to the biological reactor (anaerobic, aerobic, anoxic tank) or the machinery or structure of the secondary settler, there is no connection between the different set of biological reactors (exhaler) and the second settler. However, it was not possible to operate effectively such as stopping the operation of the heat.

In particular, in the case of high biological treatment, a large amount of gas is attached to the sludge flowing out of the aerobic reaction tank, resulting in poor precipitation and excessive scum.

Under biological treatment, one of the biggest problems with secondary sediments in wastewater treatment plants is the effect of density flows.

Most sedimentary theory developed in the sedimentation basin of the waterworks, and the cause of the density flow is different from the sedimentation basin of the sewage treatment plant and the secondary sedimentation basin of the sewage treatment plant.

In waterworks, the concentration of suspended solids in the sedimentation basin is only a few tens of mg / L, so the density flow due to the difference in concentration is relatively small, and the density flow due to the temperature difference of the influent occurs mainly, and it occurs intermittently. In the secondary sedimentation basin, the sludge concentration is about 1,500 to 2500 mg / L when the conventional activated sludge method is used, and it is very high as 3,000 to 6,000 mg / L when the altitude is used. In the case of the treatment plant, the flow rate from the sedimentation basin to the microbial reactor is 100-300% and the flow rate adjustment tank is often provided. Since the daily water temperature change is smaller than that of the sewage treatment basin, the density flow generated in the wastewater treatment plant is mainly introduced. It is a density | density flow by the concentration difference of a liquid mixture, and it has the characteristic to generate | occur | produce continuously throughout the year.

And it is not a problem in most cases because there is almost no scum in the sewage treatment plant, but it is very important to remove this effectively because a large amount of scum is generated in the secondary sedimentation basin of the wastewater treatment plant.

When a dense flow occurs, the water in the sedimentation basin flows slowly into the laminar flow, so that they do not mix with each other, and a dense mixture flows rapidly along the bottom of the sedimentation basin, and collides with the wall at the end of the sedimentation basin (see Fig. 8). )

Therefore, the secondary sedimentation basin in the biological treatment plant has a very high concentration of mixed liquor, so that the density flow continuously occurs throughout the year, so countermeasures need to be taken. By collecting the supernatant water at the position where the influence of the density flow is greatest, the influence is even greater, and a large amount of suspended matter is mixed in the supernatant water, which is a great cause of deterioration of the supernatant water quality.

In order to prevent this, the supernatant water collecting device may be installed at a position far away from the tip of the sedimentation basin which is less affected by the density flow. In this case, however, the scum on the surface of the sediment that occurs within the distance cannot be removed. This filth caused disgust, odors, pests, and other problems. The scum on the surface of the water was mixed with some water or worsened.

Although some of the supernatant catching weirs are arranged in the length direction of the sedimentation basin in the water treatment plant sedimentation basin, the width of the sedimentation basin is wide and the support column is installed in the middle. As the number of Froude (Fr) expressed by the cross-sectional area / cut length is small, the water flow is unstable and sedimentation is not easy.The density flow generated in the sewage treatment plant is mainly caused by the temperature difference of water. Can not avoid the effects of density flow (S. Kawamura. Optimal Design and Maintenance of Water Purification Facilities (December 3, 1997) .p. 142, published by Clean Techno Co., Ltd.) Since there is no function, the installation of the collecting weir in the longitudinal direction of the sedimentation basin is a secondary sedimentation basin in the wastewater treatment plant. It will not be applied.

In other cases, there is an attempt to prevent the influence of the density flow by installing an obstruction plate in the rising part of the density flow, but there is a problem that it is difficult to apply because the rising position or strength of the density flow varies depending on the degree of density difference, inflow, and wastewater.

The technical problem to be achieved by the present invention is an equal flow distribution and air stripping at the back end of the aerobic reaction tank, the influent is introduced at an even rate without destroying the floc at the inlet of the sedimentation basin, and the supernatant is located near both walls of the sedimentation basin. By collecting water from the collecting device, the influence of density flow is reduced, and the scum on the water is transported and removed from the front to the rear of the sedimentation basin to provide a rectangular secondary sedimentation basin at the wastewater treatment plant to improve the sedimentation efficiency and scum removal efficiency. will be.

The present invention to achieve the above technical problem,

Install the overflow weir 1 of the same length as the exhalation reactor width at the rear end of the exhalation reactor (a), but incline the upper surface of the overflow weir downwards by 10 to 15 degrees;

After the weir (1), the degassing tank (2) is formed in the same length as the entire width of the settling basin;

A pipe diffuser 3 is installed below the degassing tank 2;

After the degassing tank 2, the raceway 4 is installed, the equal distribution pipe 7 is installed so that the partition 6 can penetrate, and the adjustment gate 5 is installed in front of the equal distribution pipe;

The outlet side of the equal distribution pipe 7 is provided with an inclined portion 8 having an inclination of 30 to 45 °, and is made of a thin plate supported by a reinforcing material after the inclined portion, and has an opening section area of 4 to 6%. A hole rectifying wall 9 is installed;

The width of the sedimentation basin (B) is limited to within 6 m, the upper part of the sedimentation basin is covered with the sedimentation slab (D), and the orifice-type supernatant water collecting device 11 near the surface of the sedimentation basin (B) is placed near the water surface. It is installed from the front side to the rear end of the sedimentation basin, and the tip of the upper water collecting device is connected to the upper water drainage channel 13, and the outside of the upper water collecting device 11 has a scum prevention plate 12 having a width of 100 to 300 mm from the water surface of 50 to 100 mm deep, integrally formed on the wall of the upper water collecting weir 11 in the horizontal direction, and the guide rail 17-2 for the flight 17-1 is fixed to the upper portion of the scum prevention plate 12 The orifice hole (11-2) of the supernatant catcher 11 is drilled at regular intervals from the front of the supernatant catcher 11, and is installed up to a position of 3 to 5 m from the rear of the supernatant catcher. ;

The sludge collector 17 is installed from the front pore rectifying wall 9 of the sedimentation basin to the scum removal channel 15 at the rear end of the sedimentation basin, and the flight 17-1 of the sludge collector is at both ends thereof. Is installed close to the wall of (11), and is installed above the scum prevention plate (12);

The scum removal channel 15 has the upper end of the channel wall submerged 1 to 2 cm from the surface of the water, forms a channel in the width direction of the sedimentation basin, and a scum transport channel 15-3 of four cross-sections beneath the channel is sealed. A through hole 15-2 is formed between the scrubbing removal channel and the scum transfer channel, and a scum valve 19 is provided on the through hole 15-2, and the scum transfer channel 15-15 is formed. A scum discharge pipe 16 is installed in the lower part of 3); And

The equal distribution tube 7 is composed of an inlet section of a four-sided section and a long channel-type distribution section such as the width of the settling basin. The distribution section forms several circular holes 7-1 horizontally with each other from the center to each other. A rectangular secondary sedimentation pond of an improved biological loading and wastewater treatment plant, characterized in that it is symmetrical, but the size of the circular hole is gradually increased from center to edge.

The configuration of the present invention is as follows.

Overflow weir (1) is installed at the outlet of the aerobic reaction tank (A), but the upper surface of the overflow weir (1) has a slope of 10 to 15 ° downward, and stayed for 3 minutes after the overflow weir (1) The degassing tank 2 of the square section of width and depth which has time was formed.

The height of the overflow weir (1) was determined to have the smallest drop with respect to the maximum flow rate, but not to reverse flow of the wastewater from the degassing side.

At the bottom of the degassing tank (2), a pipe diffuser pipe (3) is installed long in the degassing tank length direction so that air can be blown into the degassing tank, and the degassing tank (2) is allowed to penetrate the degassing tank next to the common channel. Formed.

After the degassing tank 3, a shallow water channel 4 is provided to maintain the speed at which solids in the mixed liquid do not settle, and a partition 6 is installed next to the water channel, whereby a mixed liquid of The waste water) is allowed to flow through the equal distribution pipe 7 installed to penetrate the partition wall, and an adjustment gate 5 is provided at the inlet of the even distribution pipe 7.

Next to the equal distribution tube 7, a downward inclined portion 8 of 30 to 45 ° is provided, and at a distance of 1.5 to 2 m from the end of the inclined portion, it has a hole cross-sectional area of 4 to 6% of the total transverse cross-sectional area of the settling basin. Perforated rectifying wall 9 made of sheet material was installed.

Perforated rectifying wall of thin plate was supported by reinforcement to secure the required strength.

Inside the sedimentation basin (B), an orifice-type super water collector 11 is installed near both sides of the sedimentation basin wall 10 to the rear end of the sedimentation basin near the rectifying wall of the sedimentation basin (B). It was connected to the drain 13.

A scum prevention plate 12 having a width of 100 to 300 mm is horizontally installed at a depth of 50 to 100 mm from the surface of the supernatant water collecting device 11, but is perpendicular to the wall of the water collecting device 11. (90 °) to be fixedly installed and installed on the upper surface of the scum prevention plate 12, the guide rail 17-2 of the flight 17-1 is fixed to install the scum prevention plate 12 to guide rail support It was to be used as.

In the structure behind the settling basin of the scum prevention plate 12, the scum prevention plate 12 was not installed in a part of the supernatant water collecting device 11 so that the flight 17-1 of the sludge collector 17 can pass.

The sludge collector 17 is a chain-flighted sludge collector, which extends from the rear of the pore rectifying wall 9 of the sedimentation basin to the scum removal channel 15 at the rear of the sedimentation basin and to the rear wall of the sedimentation basin at the sediment bottom. It was possible to transport all the sludge deposited on the scum and sediment bottom 18 above.

The scum discharge channel 15 is installed in the transverse direction at the end of the sedimentation basin, and the upper end of the wall of the scum removal channel 15 is submerged 1 to 2 cm from the surface of the water. (15-3) was installed in a sealed structure, and penetrated with the scum removal channel through the through hole (15-2), and a scum valve (19) was installed and opened and closed on the through hole.

The transferred scum is transferred to the next process through the scum discharge pipe 16 and processed, and the supernatant water is transferred to a coagulation precipitation process or a disinfection facility, which is the next process, through the supernatant drain pipe 14.

The equal distribution tube 7 is shaped as shown in [Fig. 7]. The uniform distribution tube 7 has a cross section that is reduced toward the end of the width direction, and the distribution hole 7-1 is extended from the center to both ends. Increasingly, the hole diameter was increased so that the distribution of wastewater was uniform.

The operation of the present invention is as follows.

The wastewater transferred from the aerobic reaction tank (A) is distributed evenly through the equal flow pipe (7) through the degassing tank (2) and the waterway (4) through the overflow weir (1), and the perforated rectifying wall of the sedimentation basin. It is conveyed to (9) side.

Since the upper surface of the overflow weir (1) is inclined downward by 15 °, the sewage and wastewater over the weir flows through the upper surface of the overflow weir without directly falling freely, so that flocs in the wastewater are not destroyed. maintain.

The degassing tank 2 has a residence time of 3 minutes or more, and the agitation action of the air supplied from the pipe diffuser 3 removes fine air bubbles attached to the sludge in the waste water, thereby preventing the sludge from rising. Since the amount of scum is reduced and the cross section of a sufficient size is used, even if the operation is stopped in the aerobic reaction tank or the sedimentation basin due to equipment failure, the remaining sedimentation basins serve to distribute the waste water evenly.

The equal distribution pipe 7 serves to uniformly distribute the inflow of the wastewater into the sedimentation basin width direction to prevent the flow of the wastewater flowing into the sedimentation basin.

Since the distribution hole of the equal distribution pipe 7 is larger toward both ends, it distributes the waste water evenly without being affected by the loss head.

In the raceway 4, the sludge is not precipitated in the raceway because the width and depth of the raceway are determined so as to maintain a flow rate of 0.1 m / s or more when the wastewater passes through the wastewater.

The regulating water gate acts to block the inflow of wastewater into the sedimentation basin in case of imbalance between the sedimentation basin and wastewater inflow or the shutdown of the sedimentation basin.

In the inclined portion 8 provided next to the equal distribution pipe 7, the inflow of the lower and waste water is further spread so as to approach the pore rectifying wall 9 at an equal speed.

The perforated rectifying wall 9 is made of a thin plate, so that the sludge in the wastewater does not settle or accumulate in the rectifying holes due to passing through the rectifying holes 9-2, which are perforated in the perforating rectifying walls, and the rectifying effect is improved. The best pore area ratio is 4 to 6%, so that the wastewater passes through the pore rectifying wall 9 and the sewage is transported at an equal flow rate across the entire cross-section of the sedimentation basin, causing sedimentation.

However, due to the characteristics of the secondary sedimentation basin of sewage, the sewage and wastewater, including sludge with high concentration, are introduced. Therefore, density flows occur as shown in [Figure 8], and the sewage and wastewater does not flow evenly over the entire cross-sectional area of the sedimentation basin. Moves rapidly along the bottom of the sedimentation basin to the rear end of the sedimentation basin and rises towards the surface of the sedimentation basin at the rear end of the sedimentation basin due to the movement speed.

As described above, the density flow generated in the sedimentation basin of the waste water treatment plant is caused by the high concentration of the waste water and there is a difference in characteristics from the density flow caused by the water temperature difference.

Density flow due to water temperature difference is a low temperature of the separated supernatant after sludge settling, so it has a tendency to maintain the density flow, which hinders sedimentation. Because the temperature is the same as, it is easily mixed and diffused in the water existing in the sedimentation basin and does not interfere with the sedimentation.

As shown in [Figure 8], it can be seen that the density stream including the sludge is almost evenly distributed in the overall length direction of the sedimentation basin, which is almost the same as the sludge distribution of the upstream sedimentation basin.

Therefore, the use of the supernatant water collection method at the rear end of the sedimentation basin which is generally used in the cross-flow sedimentation basin may further promote synergy of the density stream, which may not settle well and may cause sludge to be discharged into the supernatant.

However, if the supernatant collecting device is installed in the longitudinal direction of the sedimentation basin and the supernatant is not collected at a certain distance from the rear end of the sedimentation basin and the supernatant is collected in the remaining sections, the supernatant is collected while flowing in a direction perpendicular to the direction of the flow of the density of the sedimentation basin. Without being influenced by the speed of the density flow, precipitation action occurs, the influence of the density flow is reduced, and clean supernatant water can be obtained.

In this case, too, there may be some increase in the density flow at the rear end of the sedimentation basin, so that the supernatant is not collected at a certain distance (for example, 3 to 5 m) from the rear end of the sedimentation basin.

When the orifice collecting device 11 is used for the supernatant water collecting device 11, and the orifice hole 11-1 is only submerged in water, the water level difference between the orifice holes and the orifice hole size are large, regardless of the height difference of the orifice holes. As the flow rate is determined only, even water collection is achieved, so it is easier to install the super water collection over a longer distance than triangular weir type, and the water collection is stable evenly because it is not affected by wind or wave. Can be done.

The scum that floated on the surface of the sludge collector installed on the scum prevention plate 12 horizontally installed on the wall of the supernatant water collecting device 11 is installed to fit between the walls of the supernatant water collecting device 11. While moving from the front of the sedimentation basin to the rear of the settling basin by pushing it to the front of the scum removing channel 15 and opening the scum valve 19, water and scum on the surface of the sedimentation basin together into the scum removing channel 19 Since it flows in and is discharged and removed outside through the scum transfer channel 15-3, scum on the water surface is completely removed.

Scum removal is performed by running the sludge collector continuously and opening and closing the scum valve 19 periodically.

The chain-flighted sludge collector 17 operates to transfer scum on the surface of the water while operating, and transfers sludge deposited at the bottom of the sedimentation basin to a sludge hopper (bar) in front of the sedimentation basin.

Since the flight 17-1 of the sludge collector moves on the flight guide rail 17-2 fixedly installed on the scum prevention plate 12 installed horizontally on the wall of the supernatant water collecting device 11, the flight guide rail Since it also serves as a support, there is no need to install a support for supporting a separate flight guide rail 17-2 is very economical and easy to install.

The present invention has been described with reference to the drawings mainly described for the secondary biological battery of the improved biological load, wastewater treatment plant with specific conditions, which can be modified and modified innumerable by those skilled in the art all these changes and modifications of the present invention It should be interpreted as being included in the scope of protection.

In the improved biological sewage treatment plant of the present invention, the secondary sedimentation battery of the wastewater treatment plant has less scum generated due to degassing of the wastewater at the inlet, the wastewater is evenly distributed, and the influence of density flow in the sedimentation basin is reduced, It has high sedimentation efficiency, and it effectively removes scum on the surface, improving the upper water quality, securing visual cleanliness, preventing odor and harmful insects, and by installing the guide rail of the flywater collecting device and scum prevention plate. There is no need for a separate flight guide rail, so it is easy to install and economical.

Claims (2)

A monthly weir (1) installed at the rear end of the aerobic reactor (A) with the same length as the aerobic reactor, and inclined at an angle of 10 to 15 degrees downward; A degassing tank 2 formed after the overflow weir 1 in the same length as the entire width of the sedimentation basin; A pipe diffuser 3 installed below the degassing tank 2; A raceway 4 provided after the degassing tank 2; An equal distribution pipe 7 installed to penetrate the partition wall 6 connected to the raceway; The equal distribution pipe is composed of an inlet portion having a quadrangular section and a distribution portion of a long channel type such as the width of the sedimentation basin, and the plurality of circular holes 7-1 are formed horizontally in the distribution portion, and the size of the circular hole is centered. An evenly distributed tube (7), which is gradually larger towards the edge at An adjustment gate 5 installed in front of the even distribution tube; An inclined portion 8 having an inclination of 30 to 45 degrees provided on the outlet side of the equal distribution pipe 7; A perforated rectifying wall 9 made of a thin plate supported by a reinforcing material having an opening cross-sectional area of 4 to 6% and installed next to the inclined portion; An orifice-type supernatant water collecting device 11 installed at both front and rear ends of the sedimentation basin at a height corresponding to the height of water on both settler walls 10 of the sedimentation basin, the upper part of which is covered with a slab (la), having a width of the sedimentation basin within 6 m; An orifice hole (11-2) formed by drilling at regular intervals between the front and rear ends of the upper water collecting device (11) from 3 to 5 m before the rear end; A scum prevention plate 12 horizontally installed on the outer wall of the supernatant water collecting device 11 at a depth of 50 to 100 mm from the surface of the water; A guide rail 17-2 for the flight 17-1 fixed to the upper portion of the scum prevention plate 12 and installed; From the front pore rectifying wall (9) of the sedimentation basin to the front of the scum removal channel (15) at the rear end of the sedimentation basin, the flight runs from the front of the sedimentation basin to the rear along the above guide rails (1 7-2). A sludge collector 17 which moves the scum on the water surface to the front of the scum removal channel 15 and transfers the sludge deposited at the bottom of the sedimentation basin to the sludge hopper in front of the sedimentation basin; A flight 17-1 of the sludge collector installed on the upper side of the scum prevention plate 12, the end of which is fitted between the walls of the two supernatant collectors 11; A scum removing channel 15 in which an upper end of the channel wall is submerged 1 to 2 cm from the surface of the water and the channel is formed in the width of the sedimentation basin; A scum conveying channel 15-3 having a quadrangular cross-sectional structure formed under the scum removing channel 15 in a sealed structure; A through-hole 15-2 formed between the skid removing channel and the scum conveying channel; A scum valve 19 provided on the through hole 15-2; And Rectangle secondary sedimentation basin of the improved biological load, wastewater treatment plant, characterized in that consisting of the scum discharge pipe (16) installed in the lower portion of the scum transfer channel (15-3). delete

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