KR100861022B1 - Improved rectangular sedimentation basins - Google Patents

Abstract

An improved rectangular sedimentation basin is provided to improve sedimentation efficiency and scum removal efficiency by reducing influence of density currents and transferring scum on the surface of water from a front side of the sedimentation basin to a rear side thereof, thereby removing the scum. An improved rectangular sedimentation basin comprises: an overflow weir(1) installed in an inlet part of the sedimentation basin; an air stripping tank(2) having a length that is the same as a width of the sedimentation basin; an air diffuser(3) installed on a bottom part of the air stripping tank; link canals(4) installed next to the air stripping tank; equal distribution pipes(7) which pass through the link canals, and which include rectangular cross-sectional inlet parts and long channel type distribution parts; adjusting sluice gates(5) installed in front of the equal distribution pipes; inclined parts installed on rear ends of the equal distribution pipes; influent temperature sensors(23) installed in water of the inclined parts; perforated baffle walls(9) installed in front of the sedimentation basin; sedimentation basin structures which have widths limited to less than 6 m, and of which top parts are covered; orifice type overflow weir equipment(11) installed on both sedimentation basin walls(10) of the sedimentation basin; scum preventing plates(11-5) horizontally installed on inner walls of the overflow weir equipment; flight guiding rails installed on the scum preventing plates; orifice holes formed in a constant distance on the inner walls of the overflow weir equipment under the scum preventing plates; overflow water channels formed at an upper side of the overflow weir equipment, and intermediate water channels formed at a lower side thereof; intermediate water collecting pipes(12) installed longitudinally and laterally at a water depth of 1.2 to 1.8 m of the sedimentation basin; orifice holes formed in the intermediate water collecting pipes; temperature sensors(22) installed on the intermediate water collecting pipes; intermediate water adjusting valves(20) installed on ends of the intermediate water channels; sludge collectors(17) which are installed from the front side to the rear side of the sedimentation basin, and of which flights(17-1) move on the scum preventing plates; scum removing channels(15) formed in the width direction of the sedimentation basin; and scum valves(19) installed in through holes of the scum removing channels.

Description

Improved rectangular sedimentation basins

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 of the sedimentation basin inlet of the present invention.

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

11-3. Superiority channel 11-4. Medium channel 11-5 scum prevention plate

12. Medium water collecting pipe 12-1. Orifice hole

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. Medium water control valve

21. Sludge Drawing Pipe

22. Temperature sensor.

23. Influent temperature sensor.

end. Agglomerated paper or aerobic reactor; Sedimentation c. Communal sphere

la. Sedimentation slab e. Agglomerated slab bars. Sludge hopper

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

Conventional rectangular sedimentation basins of tap water treatment plants and rectangular secondary sedimentation basins in wastewater treatment plants may have unreasonable structures, causing flocs in the mixed liquor to break or drift, resulting in poor sedimentation.

In addition, when the parts were shut down due to damage to the machinery or structure of the facilities related to the sedimentation basin, there was no proper connection between the facilities of different heats, and the operation of the heats could not be performed effectively.

In the case of excessive dissolution of air in raw water in a water treatment plant or high biological treatment, a large amount of gas is attached to the sludge flowing out of the aerobic reactor, resulting in poor sedimentation and excessive scum.

One of the biggest problems that occurs in rectangular sedimentation basins in water treatment plants or secondary sedimentation basins in wastewater treatment plants under biological treatment is the effect of density flow.

Density flows come from concentration differences and from raw water temperatures.

In the waterworks, the concentration of suspended solids in the sedimentation basin is only a few tens of mg / L, so the density flow is relatively small due to the difference in concentration, and the density flow is mainly caused by the temperature difference of the influent. The concentration of sludge is about 1,500-2,500 mg / L in case of using the conventional activated sludge method in the intestinal secondary sedimentation basin, and it is very high as 3,000-6,000 mg / L in case of advanced treatment. 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 purification plant sedimentation basin, the density flow generated in the wastewater treatment plant is mainly introduced. The effect of density is greatly influenced by the concentration difference of the mixed liquid, and it is characterized by continuous occurrence throughout the year. And, according to local conditions or the ambient conditions in the wastewater treatment plants is sometimes the mildoryu by the temperature difference between the inlet water occurs.

Since scum is generated in secondary sedimentation basin of wastewater treatment plant, it is very important to effectively remove scum, and scum removal is also important because scum is generated depending on the surrounding conditions and water quality in water 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). )

When a dense flow occurs, hot water does not flow out of the sedimentation basin through the catchment system, but continues to circulate in the sedimentation basin to form dead zones (four dead zones), reducing the hydraulic retention time of the sedimentation basin. As a result, suspended solids are contained in the supernatant, which deteriorates the supernatant water quality.

The technical problem to be achieved in the present invention is a rectangular sedimentation basin inlet, even flow distribution and degassing (air stripping), the inflow water is introduced at an even rate without destroying the floc, the supernatant in the catchment device near both walls of the sedimentation basin Improved rectangular sedimentation basin by collecting and draining the stagnant water by intermediate water collecting system to reduce the influence of density flow, and removing scum on the surface from the front to the rear of the sedimentation basin to increase sedimentation efficiency and scum removal efficiency. To provide.

The present invention to achieve the above technical problem,

Install a monthly weir 1 equal to the width of the sedimentation basin at the inlet of the rectangular sedimentation basin with the top surface of the overflowing weir inclined downward by 10 to 15 °;

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 evenly distributed tube 7 is provided with an inclined portion 8 having an inclination of 30 to 45 degrees, an inflow water temperature sensor 23 is installed in the water of the inclined portion, and a thin portion supported by a reinforcement material after the inclined portion. A porous hole rectifying wall 9 made of a sheet material and having an opening end area of 4 to 6%;

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 supernatant water collecting device is connected to the upper water drainage channel 13, and the scum prevention plate 12 having a width of 100 to 300 mm is formed on the wall of the sedimentation basin inside the supernatant water collecting device 11. Install horizontally at a depth of 50-100 mm from the wall of the supernatant water collecting device 11 so as to be integrally formed at a right angle (90 °), and above the scum prevention plate 12 for flight 17-1. The guide rail 17-2 is fixed and installed, and the orifice hole 11-2 of the upper water collecting weir 11 is drilled at regular intervals from the front of the upper water collecting device 11 to the rear, and the upper water collecting device Install only up to 3 to 5 m from the back of the front;

The upper portion of the canal water collecting device 11 of the upper portion of the upper canal channel 11-3, the lower portion of the water channel 11-4,

Between the front and rear of the sedimentation basin, three intermediate water collecting pipes 12 in the transverse direction and two longitudinal directions are installed at a depth of 1.2 to 1.8 m, and both ends of the intermediate water collecting pipes have intermediate water channels ( 11-4), an orifice hole 12-1 is formed in both sides of the intermediate water collecting pipe in the horizontal direction, and a temperature sensor 22 is installed on the intermediate water collecting pipe, and the intermediate water collecting channel 11- At the end of 4), an intermediate water control valve 20 is installed;

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 (11-5);

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 scum 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- is formed. A scum discharge pipe 16 is installed in the lower part of 3); And

The even distribution pipe 7 is composed of a long channel-type distribution part such as an inlet part of a four-sided section and a width of the settling basin, and has a circular hole 7-1 of a predetermined size and number horizontally formed in the distribution part. The size of the hole provides an improved rectangular settler, characterized in that the size is gradually increased from the center to the edge.

The configuration of the present invention is as follows.

Overflow weir (1) is installed at the inlet of the rectangular sedimentation basin, but the upper surface of the overflow weir (1) has a slope of 10 to 15 ° downward, and stays for 2 to 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 reflux the water on the degassing tank 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 waterway 4 is installed to maintain the speed at which solids do not settle in the inflow water, and a partition 6 is installed next to the waterway so that the inflow water penetrates the partition wall. It was allowed to flow through the equal distribution pipe (7), and the adjustment gate (5) was installed at the inlet of the even distribution pipe (7).

After the equal distribution pipe 7, a downward inclined portion 8 of 30 to 45 ° is provided, and an inflow water temperature sensor 23 is provided on the inclined portion, and the entire transverse area of the sedimentation basin is 1.5 to 2 m away from the end of the inclined portion. A hole rectifying wall 9 made of a thin plate having a hole cross-sectional area of 4 to 6% with respect to the cross-sectional area was provided.

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

Inside the sedimentation basin (B), an orifice-type supernatant water collecting unit (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.

The scum prevention plate 11-5 having a width of 100 to 300 mm is installed horizontally at a depth of 50 to 100 mm from the surface of the wall of the supernatant water collecting device 11, but the wall of the upper water collecting device 11 is installed horizontally. And fixed at right angles (90 °) to the unit, and the guide rails (17-2) of the flight (17-1) are fixedly installed on the upper surface of the scum prevention plate (11-5) to prevent scum prevention plate (11-) 5) was used as a guide rail support.

The structure behind the sedimentation basin in relation to the scum prevention plate 11-5 is the scum prevention plate 11-5 installed on the supernatant water collecting device 11 so that the flight 17-1 of the sludge collector 17 can pass. Only installed near the sprocket shaft (not shown in the drawing, not shown) at the rear of the water surface of the collector 17.

The upper portion of the upper canal water collecting device 11 forms a upper canal channel 11-3, the lower part has an intermediate channel 11-4, and the rear end of the middle channel 11-4 has an intermediate portion. The water control valve 20 was installed.

Install a middle water collecting pipe 12 at a depth of 1.2 ~ 1.8m (depending on the depth of the settling) of the rectangular sedimentation basin, and install two horizontally in the longitudinal direction of the sedimentation basin and three horizontally in the width direction of the sedimentation basin Both ends of the intermediate water collecting pipe 12 installed in the direction are connected to the intermediate water channel 11-4, and a temperature sensor 22 is installed on the intermediate water collecting pipe 12, and the influent water temperature sensor 23 is provided. The over temperature sensor 22 and the intermediate water control valve were interlocked.

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 has a shape as shown in [Fig. 7]. The equal distribution tube 7 has a cross section that is reduced toward the end of the width direction, and the distribution hole 7-1 has a central portion at both ends. The large pore diameter ensures an even distribution of influent.

The operation of the present invention is as follows.

The influent from the agglomeration basin of the water treatment plant or the aerobic tank of the biological sewage / wastewater treatment plant is distributed evenly through the monthly weir (1) through the equally degassing tank (2) and the waterway (4) through the equal distribution pipe (7). It is conveyed toward the hole rectifying wall 9 of.

Since the upper surface of the weir flow (1) is inclined downward 15 °, the inflow water over the weir flows through the upper surface of the weir flow without directly falling freely, so the floc in the inflow water is not destroyed, and thus the sedimentability is maintained well.

The degassing tank 2 has a residence time of 2 to 3 minutes or more, and by removing the air bubbles attached to the sludge in the inflow water by the stirring action of the air supplied from the pipe diffuser 3 to prevent the sludge from rising It reduces the amount of scum generated and has a cross section of sufficient size, so that even if the operation is stopped due to a failure in any of the facilities related to the sedimentation basin, the influent is evenly distributed to the remaining sedimentation basins.

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

The distribution hole of the equal distribution tube 7 is larger in size toward both ends, so that the equally influent water passes through without being affected by the loss head.

In the raceway 4, the sludge is not precipitated in the raceway because the channel and width are defined so as to maintain a flow rate of 0.1 m / s or more when passing through the influent.

The regulating water gate serves to block the inflow of influent into the sedimentation basin when the inflow of the inflows between the sedimentation basins is unbalanced or when the sedimentation basin is shut down.

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

The perforated rectifying wall 9 is made of a thin plate, so that sludge in the inflow water passing through the rectifying hole 9-2 perforated in the perforated rectifying wall does not settle or accumulate in the rectifying hole and has the best rectifying effect. Since the pore area ratio is 4 to 6%, the inflow water passing through the pore rectifying wall 9 is transported at an equal flow rate across the entire cross section of the sedimentation basin, and precipitation occurs.

However, if the temperature difference between the influent and the water in the sedimentation basin of the sewage plant is large, a density flow as shown in [Figure 8] occurs, so that the inflow does not flow evenly over the entire cross-sectional area of the sedimentation basin. It moves at a speed to reach the sedimentation basin and rises from the sedimentation basin towards the sediment basin surface under the influence of travel speed.

As shown in [Fig. 8], the density flow including sludge is distributed over the entire length direction at the bottom of the sedimentation basin, and the high temperature water is circulated in the sedimentation basin without being discharged to the outside. It forms a zone that prevents normal precipitation.

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. It is not affected 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.

However, as shown in Fig. 8, the density flow is mainly caused by the water temperature difference, but when the density flow is caused by the temperature difference, the temperature difference is high because the water with high water temperature continuously circulates in the sedimentation basin from the upper part of the sedimentation basin to the rear to the front. The influence of density flows by is not completely excluded.

The density flow caused by the water temperature difference is known to form a clear density flow even when the temperature of the influent water is only 0.5 ° C lower than the water temperature in the sedimentation basin.

Therefore, this stagnant water (hereinafter referred to as intermediate water) must be removed to quickly reduce the influence of the density flow.

In the present invention, by comparing the temperature of the influent temperature sensor 23 and the temperature sensor 22 for measuring the temperature of the intermediate water, if the influent water temperature is lower than 0.4 ℃ or more than the intermediate water temperature automatically opens the intermediate water control valve 20 The intermediate water is discharged through the intermediate water collection pipe 12, and when the temperature difference between the intermediate water and the inflow water becomes 0.2 ° C, the intermediate water control valve 21 is closed.

When the intermediate water control valve 20 is suddenly opened, disturbance occurs in the flow in the sedimentation basin due to hydraulic shock, thereby preventing the precipitation, so that the opening and closing of the intermediate water control valve 21 is made slowly, and the medium water discharge rate is also very slowly discharged. Decided.

As described above, when the intermediate water is discharged, the sedimentation basin has an even flow velocity distribution across the sedimentation basin, and sedimentation takes place effectively.The effect of density flow due to the concentration difference without temperature difference is the supernatant water collecting device installed on both walls in the longitudinal direction (11). It is alleviated by the action of), which effectively precipitates and cleans the supernatant.

The supernatant water collecting device 11 uses an orifice type water collecting device, and as long as the orifice holes 11-1 are all submerged in water, even water collection is achieved regardless of the height difference of the orifice holes, so that The catchment is easier to install than the triangular weir type, even water collection is made, and because it is not affected by wind or waves, stable water collection is always performed.

The scum that floated on the surface of the sludge collector installed on the scum prevention plate 11-5 installed horizontally on the wall of the supernatant water collecting device 11 fits tightly between the walls of the supernatant water collecting device 11. In the installed state, it moves forward from the front of the sedimentation basin to the rear and slides it to the front of the scum removing channel 15, and when the scum valve 19 is opened, the water and the scum on the surface of the sedimentation basin are combined with the scum removing channel (19). The scum on the surface of the water is cleanly removed since it flows into the inside and is discharged to the outside through the scum transfer channel 15-3.

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 a flight guide rail 17-2 fixedly mounted on the scum prevention plate 11-5 installed horizontally on the wall of the supernatant water collecting device 11, Since also serves as a flight guide rail 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 mainly described with reference to the drawings for the secondary sedimentation battery of the improved biological influent treatment plant with specific conditions, which can be modified and modified innumerable by those skilled in the art all these changes and modifications are within the protection scope of the present invention. It should be interpreted as being included.

Improved rectangular sedimentation basin of the present invention is less in scum by inlet water degassing in the inlet, evenly distributed inlet, the influence of density flow due to temperature difference and concentration difference in the sedimentation basin, sedimentation efficiency can be collected by the supernatant This high, effective water removal of scum on the surface improves water quality, secures visual cleanliness, prevents bad odors and prevents harmful insects, and installs a separate flight guide rail by installing flight guide rails on the supernatant water collecting device and scum prevention plate. It is easy to install and economical as there is no need for support.

Claims (1)

It is provided in the inlet part of the rectangular sedimentation basin, and the upper surface is a weir (1) installed inclined downward 10 to 15 °; A degassing tank 2 formed in the same length as the width of the sedimentation basin; A pipe diffuser 3 installed in the lower part of the degassing tank; A raceway 4 provided after the degassing tank; It is divided into the inlet part of the cross section and the long channel type distribution part such as the sedimentation basin width, and the distribution part has an equal part which has several distribution holes 7-1 formed larger from the center to the edge. A pipe 7; An adjustable sluice 5 installed in front of the equal distribution pipe; An inclined portion 8 provided at a rear end of the equally distributed pipe with a downward slope of 30 to 45 degrees; An inflow water temperature sensor 23 installed in the water of the inclined portion; A perforated rectifying wall 9 formed of a thin plate supported by a reinforcing material, having an opening cross-sectional area of 4% or more, and installed in front of the sedimentation basin; Each of the sedimentation basin structures whose width is limited to 6 m and covered thereon; An orifice type supernatant water collecting device 11 installed on both settling wall walls 10 of the settling basin; A scum prevention plate 11-5 having a width of 100 to 300 mm installed horizontally on an inner wall of the supernatant water collecting device 11 and installed at a depth of 50 to 100 mm from the water surface; A guide rail 17-2 for flight provided on the scum prevention plate; Orifice water holes (11-2) installed under the inner wall scum prevention plate of the supernatant water collecting device (11), perforated from the front of the sedimentation basin to the rear, and formed at regular intervals from the rear of the sedimentation basin to 3 to 5 m positions; A supernatant water channel 11-3 formed above the supernatant water collecting device and an intermediate water channel 11-4 formed below; An intermediate water collecting pipe 12 installed in the longitudinal direction and the horizontal direction at a depth of 1.2 to 1.8 m of the sedimentation basin, and connecting both ends of the horizontally installed waterway to the intermediate water channel; An orifice hole 12-1 formed in the intermediate water collection pipe; A temperature sensor 22 installed on the intermediate water collection pipe; An intermediate water control valve 20 installed at the end of the intermediate water channel; A sludge collector 17 installed from the front to the rear of the sedimentation basin so that the flight 17-1 moves on the scum prevention plate and collects scum and sludge on the water surface; A scum removal channel 15 in which a channel is formed in the width of the sedimentation basin, and the upper end of the channel is locked by 1 to 2 cm below the surface of the water, and the scum transfer channel 15-3 is formed integrally under the channel; An improved rectangular sedimentation basin characterized by consisting of a scum valve (19) provided in a through hole of the scum removal channel.

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