CN112499764A

CN112499764A - CAST biochemical pool

Info

Publication number: CN112499764A
Application number: CN202011455487.4A
Authority: CN
Inventors: 周丽颖; 刘新亭; 李星文; 刘胜利; 李清清
Original assignee: Thunip Holdings Co Ltd
Current assignee: Thunip Holdings Co Ltd
Priority date: 2020-12-10
Filing date: 2020-12-10
Publication date: 2021-03-16

Abstract

The invention relates to the technical field of sewage treatment, and provides a CAST biochemical pool, which comprises a partition wall, wherein the partition wall is arranged in the CAST biochemical pool and is provided with a plurality of gates, and the partition wall divides the CAST biochemical pool into an integral selection area and a main reaction area group; the integral type selection area is provided with a first water inlet for continuous water inlet, a water storage chamber is arranged in the integral type selection area, a second water inlet is formed in the top of the water storage chamber, the wall of the water storage chamber is provided with a plurality of gates, and the gates are arranged corresponding to the gates; the main reaction zone group comprises a plurality of main reaction zones, and the main reaction zones are connected with the water storage chamber through the gates. The invention increases the effective treatment tank volume of the sewage, further enhances the denitrification and dephosphorization effect of the CAST process, and can complete upgrading and reconstruction of the existing sewage plant.

Description

CAST biochemical pool

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a CAST biochemical pool.

Background

The CAST process is a widely used sewage treatment process, and integrates aeration and sedimentation in a tank without a secondary sedimentation tank and sludge backflow equipment. Typical CAST systems are divided into: filling water, reacting, depositing, draining and leaving unused 5 stages. The CAST process can meet the growth of various microorganisms through the continuous change of oxygenation, hypoxia and anaerobic conditions, and different biological processes are alternately carried out, so that the aims of removing organic matters, nitrifying, denitrifying and dephosphorizing are fulfilled. The CAST process biochemical pool consists of a selection area and a main reaction area, the SBR technology and a biological selector are organically combined, and the pre-biological selection area is used for further enhancing phosphorus removal and inhibiting sludge bulking.

The existing sewage plant adopts CAST technology which meets lower effluent standard and can not reach the first class A standard of the national pollutant discharge standard of urban sewage treatment plant, a plurality of groups of reaction grids are usually arranged in a biochemical pool adopted by the sewage plant to ensure continuous effluent so as to realize intermittent water inlet and outlet of each group of reaction grids and integral continuous water inlet and outlet, meanwhile, each group of reaction grids are divided into a selection area and a main reaction area, the selection area is communicated with the main reaction area, so that the water level of the two areas is the same, the water level is lowest when water is precipitated and is gradually increased to the highest water level when water is fed, the selection area can not be ensured to always operate according to the highest water level, the effective treatment volume is reduced, namely, the effective treatment time of sewage is reduced, usually 1-2 hours, and the short retention time can not meet the anaerobic and anoxic time required by the first class A technology for nitrogen and phosphorus removal, the pool capacity is insufficient and the effect is not good, so the improvement is urgently needed.

Disclosure of Invention

The CAST biochemical tank provided by the invention increases the effective treatment tank volume of sewage, further enhances the denitrification and dephosphorization effects of the CAST process, and can be used for upgrading and reconstructing the existing sewage plant.

The invention provides a CAST biochemical pool, which comprises a partition wall, wherein the partition wall is arranged in the CAST biochemical pool and is provided with a plurality of gates, and the partition wall divides the CAST biochemical pool into an integral selection area and a main reaction area group; the integral type selection area is provided with a first water inlet for continuous water inlet, a water storage chamber is arranged in the integral type selection area, a second water inlet is formed in the top of the water storage chamber, the wall of the water storage chamber is provided with a plurality of gates, and the gates are arranged corresponding to the gates; the main reaction zone group comprises a plurality of main reaction zones, and the main reaction zones are connected with the water storage chamber through the gates.

According to the CAST biochemical pool provided by the invention, the integral selection area comprises a plurality of selection areas which are communicated with each other.

According to the CAST biochemical pool provided by the invention, the integral selection area is internally fixed with the suspension type filler layer, and the suspension type filler layer is positioned in sewage of the integral selection area.

According to the CAST biochemical pool provided by the invention, the stirrer is arranged at the bottom in the integral selection area.

According to the CAST biochemical pool provided by the invention, a vertical interception screen is vertically arranged at the position 1/3-2/3 along the length direction in the main reaction zone to construct a filling zone and a water outlet zone, and a plurality of suspended biological fillers are arranged in the filling zone.

According to the CAST biochemical pool provided by the invention, the main reaction zone is also internally provided with a transverse interception screen, and the transverse interception screen is arranged at the upper part of the packing zone along the horizontal direction.

According to the CAST biochemical pool provided by the invention, the mesh gaps of the vertical intercepting screens and the transverse intercepting screens are both 3mm, the height of the vertical intercepting screens exceeds the highest water level of the main reaction zone by 1m, and the transverse intercepting screens are arranged at the position 0.5m below the highest water level.

According to the CAST biochemical tank provided by the invention, an aerator and an air pipe are arranged in the filler area, the aerator is arranged at the bottom of the filler area, the first end of the air pipe is connected with the aerator, and the second end of the air pipe is externally connected with an air supply device; the water outlet area is provided with a decanter.

The CAST biochemical pool further comprises a sludge reflux pump and a reflux pipe, wherein the sludge reflux pump is arranged at the bottom of the water outlet area, the first end of the reflux pipe is connected with the sludge reflux pump, the second end of the reflux pipe is connected with the integral selection area and used for providing sludge with a reflux ratio of 100% -150% to the integral selection area, and the reflux ratio is the ratio of sludge reflux to water inflow.

According to the CAST biochemical pool provided by the invention, the water storage chamber is defined by the water outlet weir plate and the partition wall.

According to the CAST biochemical pool provided by the invention, the integral selection area is arranged to correspond to the plurality of main reaction areas, the continuous water inlet mode is adopted, the operation water level of the integral selection area is improved, sewage rises into the water storage chamber and then is periodically and intermittently discharged to the main reaction areas through the gate, the effective treatment pool capacity of the sewage is integrally improved, compared with the traditional mode, the effective treatment pool capacity of the integral selection area is increased by 2-3 times, and the sewage treatment capacity is greatly improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a top view of a conventional CAST biochemical cell;

FIG. 2 is a front view of a conventional CAST biochemical tank;

FIG. 3 is a top view of the CAST biochemical pool structure provided by the present invention;

FIG. 4 is a front view of a CAST biochemical pool structure provided by the present invention;

reference numerals:

101: a partition wall; 102: a gate; 2: an integral selection area;

3: a primary reaction zone; 4: a first water inlet; 5: a water storage chamber;

6: a second water inlet; 7: a suspended packing layer; 8: a stirrer;

9: a vertical interception screen; 10: a filler zone; 11: a water outlet area;

12: suspended biological fillers; 13: a transverse interception screen; 14: a maximum water level;

15: an aerator; 16: an air tube; 17: decanting device;

18: a sludge reflux pump; 19: a return pipe; 20: a water outlet weir plate;

21: a selection area; 22: a water outlet; 23: a gate opening.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. Specific meanings of the above terms in the embodiments of the present invention can be understood in specific cases by those of ordinary skill in the art.

In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of an embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

As shown in figures 1 and 2, the structure of the conventional CAST biochemical pool mainly comprises a plurality of groups of reaction cells, so as to realize intermittent water inlet and outlet of each group of reaction cells, each group of reaction cells is divided into a selection area 21 and a main reaction area 3, the tank capacity of the selection area 21 is about 10-20% of the tank capacity of the main reaction area 3, two adjacent selection areas 21 are separated and do not interfere with each other, each group of selection areas 21 and the main reaction area 3 are communicated with each other through a gate 23 arranged at the bottom, water flows pass through the selection areas 21 and then enter the main reaction areas 3 connected with the selection areas, so that the water levels of the selection areas 21 and the main reaction areas 3 are the same, the water levels are lifted and lowered simultaneously, the water level is the lowest when water is precipitated, the water level is gradually raised to the highest water level when the water is fed, the selection areas can not be ensured to operate according to the highest water level all the time, the effective treatment volume is reduced, the short retention time generally cannot meet the anaerobic and anoxic time required by the first-grade A standard process for nitrogen and phosphorus removal, so the effective treatment tank volume of the sewage is insufficient.

To this end, the present invention provides a novel CAST biochemical pool, as shown in fig. 3 and 4, comprising a partition wall 101, wherein the partition wall 101 is disposed in the CAST biochemical pool, and the partition wall 101 is provided with a plurality of gates 23, and the partition wall 101 divides the CAST biochemical pool into an integral selection area 2 and a main reaction area group; the integral type selection area 2 is provided with a first water inlet 4 for continuous water inlet, a water storage chamber 5 is arranged in the integral type selection area 2, a second water inlet 6 is arranged at the top of the water storage chamber 5, a plurality of gates 102 are arranged on the chamber wall of the water storage chamber 5, and the gates 102 are arranged corresponding to the gate openings 23 so as to be convenient for opening and closing the gate openings; the main reaction zone group comprises a plurality of main reaction zones 3 which are arranged in parallel, and the main reaction zones 3 are connected with a water storage chamber 5 through a gate 102. According to the invention, an integral selection area 2 is arranged to correspond to a plurality of main reaction areas 3, water is continuously fed through a first water inlet 4, the operation water level of the integral selection area 2 is always kept at a high water level, sewage enters a water storage chamber 5 through a second water inlet 6 at the top after rising, and then periodically and intermittently discharges water to the main reaction areas 3 through a gate 102, so that periodic and intermittent water feeding, aeration reaction, sedimentation and water discharging of each main reaction area 3 are ensured. Therefore, the traditional synchronous intermittent water inlet mode of the two zones is improved, the integral selection zone keeps high water level for continuous water inlet, water is supplied to the main reaction zone in real time through the water storage chamber and the gate, the water inlet mode of the main reaction zone is intermittent water inlet, the effective treatment tank capacity of the integral selection zone is improved, and compared with the traditional grouping type selection zone, the effective treatment tank capacity of sewage is increased by 2-3 times, and the sewage treatment capacity is improved.

According to the embodiment of the present invention, the water storage chamber 5 is enclosed by the outlet weir plate 20 and the partition wall 101, and the gate 102 is disposed on the partition wall 101 and located at the gate opening 23.

It can be understood that the integral selection area comprises a plurality of selection areas which are mutually communicated, the traditional grouping type plurality of selection areas are mutually communicated, the main structure of the original pool capacity is not changed, the transformation can be carried out, and the cost is saved.

As a further improvement, when the effective treatment tank capacity of the sewage is still insufficient, the suspension type packing layer 7 can be fixed in the integral type selection area 2, and the suspension type packing layer 7 is positioned in the sewage of the integral type selection area 2, specifically: the height of the suspended filler layer is at least 0.8m from the bottom of the pool and at most 1m from the water surface. The suspended filler layer comprises a plurality of suspended fillers which are distributed in parallel up and down, and more biological bacteria are gathered on the suspended fillers, so that the microbial biomass is increased, and the nitrogen and phosphorus removal processing capacity is improved.

In this embodiment, the hanging filler is an elastic or semi-soft polypropylene filler, and is mounted and fixed on a fixed bracket by a thread rope, and the fixed bracket is mounted in the integral selection area.

Specifically, the diameter of each piece of suspension filler is 150mm, the installation distance between every two pieces of suspension filler is 150mm, and the volume specific surface area of the suspension filler is more than 120m²/m³And the suspension filler had a porosity of 95%.

According to some embodiments of the present invention, the bottom of the integral selection area 2 is provided with a stirrer 8 for pushing water flow, ensuring the water flow velocity to be 0.6m/s, preventing sludge precipitation, and keeping sewage in full contact with the suspended filler layer, thereby ensuring better stirring and mass transfer effects.

According to the embodiment of the invention, a vertical interception screen 9 is vertically arranged at the position 1/3-2/3 in the length direction in the main reaction zone 3 to construct a filler zone 10 and a water outlet zone 11, a plurality of suspended biological fillers 12 are arranged in the filler zone 10, and the treatment capacity is improved by adding the suspended biological fillers 12 in the main reaction zone 3 and depending on more biological bacteria gathered on the suspended biological fillers 12, so as to solve the problem of insufficient capacity of an effective treatment tank for sewage.

In the embodiment, the suspended biological filler has a columnar or spherical structure, the specific gravity is close to that of water, and the suspended biological filler can float and flow in the water without being fixed.

Specifically, the diameter of the suspended biological filler is 20-25mm, and the volume specific surface area is 500-600m²/m³The porosity is greater than 95%.

As the main reaction zone of the CAST biochemical tank has two functions of an aeration tank and a secondary sedimentation tank, the suspended biological filler 12 flows out along with effluent after being precipitated, so that the suspended biological filler is intercepted by the vertical intercepting screen 9, preferably, the mesh gap of the vertical intercepting screen is 3mm, and the height of the vertical intercepting screen 9 is 1m above the highest water level 14 of the main reaction zone 3.

And, still be equipped with horizontal interception screen cloth 13 in the main reaction zone 3, horizontal interception screen cloth 13 sets up in the upper portion of filler district 10 along the horizontal direction, prevents that suspended biological filler from following the rivers loss of flowing out, and because CAST biochemical pond is according to into water, aeration reaction, sediment and drainage cycle intermittent type nature operation, the volume of drainage of cycle does not exceed 1/3 of the volume of highest retaining, therefore, horizontal interception screen cloth 13 sets up 0.5m below the highest water level 14, and the mesh gap is 3 mm.

According to the embodiment of the present invention, an aerator 15 and an air pipe 16 are provided in the packing area 10, the aerator 15 is provided at the bottom of the packing area 10, a first end of the air pipe 16 is connected to the aerator 15, a second end of the air pipe 16 is externally connected to an air supply device such as a blower, and air is supplied to the aerator 15 through the air pipe 16, so that the sewage is aerated and oxygenated, and the oxygen can decompose impurities, i.e., organic and inorganic substances, contained in the sewage.

Further, the water outlet zone 11 is provided with a decanter 17 for draining water through a water outlet 22.

According to the embodiment of the invention, the invention further comprises a sludge reflux pump 18 and a reflux pipe 19, wherein the sludge reflux pump 18 is arranged at the bottom in the water outlet area 11, the first end of the reflux pipe 19 is connected with the sludge reflux pump 18, the second end of the reflux pipe 19 is connected with the integral type selection area 2 and is used for providing sludge with a reflux ratio of 100-150% for the integral type selection area and providing a sludge environment with a certain concentration for the integral type selection area, and the reflux ratio is the ratio of the sludge reflux amount to the water inlet amount. As the reflux ratio of the traditional biochemical tank is about 20 percent, the sewage treatment effect is not ideal, and the invention improves the nitrogen and phosphorus removal capability of sewage treatment by improving the reflux ratio to 100 to 150 percent.

Based on the above embodiments, the technical solutions of the present invention are further described below by specific examples.

The sewage flow is 40000m³Day, the inlet water quality is: BOD₅≤160mg/L；CODcr≤300mg/L；SS≤180mg/L；TN≤45mg/L；NH₃-N≤35mg/L；TP≤4mg/L。

By adopting the CAST biochemical tank, the sewage stays for 4 hours in the integral selection area, the main reaction area stays for 18 hours, the traditional CAST biochemical tank is divided into four groups, each group is divided into two grids of the selection area and the main reaction area, the scheme is characterized in that the four separated selection areas are communicated to form the integral selection area, a plurality of pieces of suspension type filler are arranged on the integral selection area, the suspension type filler adopts elastic or semi-soft polypropylene filler and is arranged and fixed on the fixed support by a thread rope, and the fixed support is arranged in the integral selection area. The diameter of the suspension filler is 150mm, the installation distance between every two suspension fillers is 150mm, and the volume specific surface area of the suspension filler is more than 120m²/m³And the suspension filler had a porosity of 95%. The height of the suspended filler is 0.5m away from the water surface and 1m away from the bottom of the tank, and 8 stirrers are arranged at the bottom of the tank and used for pushing flow and stirring to prevent sludge from settling. The integral selection area is continuously fed with water, and the outlet end of the integral selection area is provided with a water storage chamber which is provided withFour gates are respectively communicated with the four main reaction zones, and the four gates are periodically and intermittently opened, so that water flow respectively enters the main reaction zones periodically and intermittently to carry out aeration reaction, sedimentation and drainage.

The suspended biological filler is added in the filler area, the structure of the suspended biological filler is columnar or spherical, the specific gravity of the suspended biological filler is close to that of water, and the suspended biological filler can float and drift in the water without being fixed; the diameter of the suspended biological filler is 20-25mm, the volume specific surface area is 500-600m²/m³The porosity is greater than 95%. A vertical interception screen is arranged between the filling area and the water outlet area, the gap between meshes is 3mm, and the height exceeds the highest water level by 1 m. Because the CAST biochemical pool intermittently operates according to the period of water inlet, aeration reaction, sedimentation and water discharge, the volume of water discharged in each period does not exceed 1/3 of the highest water storage volume, a transverse interception screen is horizontally arranged at a position 0.5m below the highest water level, and the mesh gap is 3 mm.

The finally treated effluent quality is as follows: BOD₅≤8mg/L；CODcr≤45mg/L；SS≤10mg/L；TN≤10mg/L；NH₃N is less than or equal to 1 mg/L; TP is less than or equal to 0.5 mg/L. The sewage treated by the CAST biochemical tank can reach the first-level A standard of the national discharge Standard of pollutants for municipal wastewater treatment plants.

Therefore, the CAST biochemical tank increases the effective treatment tank volume of sewage, further enhances the denitrification and dephosphorization effect of the CAST process, and can complete upgrading and reconstruction of the existing low-standard sewage plant.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A CAST biochemical pool comprises a partition wall, the partition wall is arranged in the CAST biochemical pool and is provided with a plurality of gates, and is characterized in that,

the partition wall divides the CAST biochemical pool into an integral selection area and a main reaction area group;

the integral type selection area is provided with a first water inlet for continuous water inlet, a water storage chamber is arranged in the integral type selection area, a second water inlet is formed in the top of the water storage chamber, the wall of the water storage chamber is provided with a plurality of gates, and the gates are arranged corresponding to the gates;

the main reaction zone group comprises a plurality of main reaction zones, and the main reaction zones are connected with the water storage chamber through the gates.

2. The CAST biochemical pool of claim 1, wherein the integral selection region comprises a plurality of selection regions in communication with each other.

3. The CAST biochemical tank according to claim 1, wherein a suspended filler layer is fixed in the integral selection area and is located in the sewage in the integral selection area.

4. The CAST biochemical pool of claim 1, wherein a bottom within the integral selection zone is provided with an agitator.

5. The CAST biochemical pool of claim 1, wherein vertical interception screens are vertically arranged at 1/3-2/3 along the length direction in the main reaction zone to construct a packing zone and a water outlet zone, and a plurality of suspended biological fillers are arranged in the packing zone.

6. The CAST biochemical pool according to claim 5, wherein a transverse interception screen is further disposed in the main reaction zone, and the transverse interception screen is disposed at an upper portion of the packing zone along a horizontal direction.

7. The CAST biochemical pool according to claim 6, wherein the vertical interception screen has a mesh gap of 3mm and the horizontal interception screen has a height exceeding 1m of the highest water level of the main reaction zone, and the horizontal interception screen is disposed 0.5m below the highest water level.

8. The CAST biochemical tank according to claim 5, wherein an aerator and an air pipe are arranged in the filler zone, the aerator is arranged at the bottom of the filler zone, a first end of the air pipe is connected with the aerator, and a second end of the air pipe is externally connected with an air supply device; the water outlet area is provided with a decanter.

9. The CAST biochemical pool according to any one of claims 5-8, further comprising a sludge recirculation pump and a recirculation pipe, wherein the sludge recirculation pump is disposed at the bottom of the outlet zone, a first end of the recirculation pipe is connected to the sludge recirculation pump, a second end of the recirculation pipe is connected to the integral selection zone, and the recirculation pump is used for providing sludge with a recirculation ratio of 100% -150% to the integral selection zone, and the recirculation ratio is a ratio of sludge recirculation amount to water inflow amount.

10. The CAST biochemical pool of claim 1, wherein the water storage chamber is enclosed by a water outlet weir plate and the partition wall.