WO2021143575A1

WO2021143575A1 - Sludge cyclone separation and activation treatment method and device

Info

Publication number: WO2021143575A1
Application number: PCT/CN2021/070283
Authority: WO
Inventors: 刘毅; 许威南; 汪华林; 孙玉萧; 韩亚芳; 魏傲松; 马凯; 徐博文
Original assignee: 华东理工大学
Priority date: 2020-01-16
Filing date: 2021-01-05
Publication date: 2021-07-22
Also published as: CN111233146B; CN111233146A

Abstract

The present invention relates to a sludge cyclone separation and activation treatment method and device. Provided is the sludge cyclone separation and activation treatment method, comprising the following steps: (i) sludge backflow separation: carrying out cyclone separation treatment on sludge so as to directionally discharge inorganic substances in the sludge as residual sludge, and returning active ingredients to a biochemical tank which comprises an anoxic tank and an aerobic tank; and (ii) internal backflow separation and activation: carrying out cyclone separation treatment on a sludge-water mixed solution at the tail end of the aerobic tank so as to return separated high-activity components to the anoxic tank for circulation, and discharge low-activity components to the aerobic tank nearby. Also provided is the sludge cyclone separation and activation treatment device.

Description

Sludge cyclone separation and activation treatment method and device

Technical field

The present disclosure belongs to the field of biochemical treatment of industrial and urban domestic sewage, and provides a sludge cyclone separation and activation treatment method and device. Specifically, a new method is provided to achieve directional mud discharge by combining cyclone treatment units, thereby improving the comprehensive degradation efficiency of the biochemical pond.

Background technique

The activated sludge method is a process for treating more than 90% of domestic sewage and more than 70% of industrial wastewater at home and abroad. It significantly improves the quality of sewage through the processes of aeration degradation of organics and oxidation, reduction and adsorption of nutrients. In recent years, with the continuous decline of environmental carrying capacity, the country has continuously improved sewage discharge standards, and the load of existing sewage treatment plants has continued to increase; in addition, the biochemical unit is frequently affected by the impact of influent water quality, uneven aeration and flow, and operation. Ponds generally have problems such as sludge expansion, poor sedimentation, and low sludge activity, which significantly inhibit the biochemical efficiency and become the key reason that restricts the typical sewage treatment plant with the biochemical unit as the core that cannot meet the discharge standards.

The problems of sludge expansion, poor sedimentation, and low sludge activity in the biochemical unit are attributable to the combination and composition ratio of the inorganic components in the activated sludge and the microbial community. In response to the above-mentioned problems and causes, scholars and engineers at home and abroad have carried out extensive technical explorations.

Chinese invention patent application CN 201110022565.6 proposed a new device design scheme for sludge separation with high sedimentation performance by activated sludge method. The separation device designed by the column-cone combination method is placed between the biological reaction tank and the secondary sedimentation tank. Control the rising flow rate of the mixed liquid of sewage and return sludge to realize the separation of activated sludge. The conventional activated sludge separation method can also be used for sludge granulation. The fluid shearing effect formed by the aeration process is used to adjust the organic composition on the outer surface of the sludge, thereby improving the sludge settling properties. Existing sludge sorting needs are widely present in the mud-ash sorting of the biochemical unit of the municipal sewage treatment plant, as well as the working conditions such as the high hardness of the incoming water and the combination of mud-ash mineralization that affect the sedimentation performance of the sludge.

However, under the above-mentioned existing research or demand conditions, the demand for sludge separation is not fully connected with the overall efficiency of the biochemical unit, and a standardized process has not been formed to continuously improve the sludge settling properties and sludge activated sludge in the biochemical tank. Therefore, the demand for emission reduction and compliance with emission standards of the biochemical unit is significantly inhibited. Therefore, it is extremely urgent to realize the long-term separation of activated sludge and inorganic matter in the biochemical unit through the combined unit and to build a mature process.

Summary of the invention

The present disclosure provides a novel sludge cyclone separation and activation treatment method and device. The cyclone treatment method is adopted to achieve directional separation and sludge discharge, which improves the sedimentation, dewatering and activity of sludge, and improves the degradation of biochemical ponds. Effectively, the remaining sludge output is reduced, thereby solving the problems existing in the prior art.

In one aspect, the present disclosure provides a sludge cyclone separation and activation treatment method, which includes the following steps:

(i) Sludge backflow sorting: the sludge is subjected to cyclone sorting treatment, so that the inorganic matter in the sludge is discharged as the remaining sludge, and the active ingredients are returned to the biochemical tank, wherein the biochemical tank includes anoxic Pool and aerobic pool; and

(ii) Internal reflux sorting activation: the mud-water mixture at the end of the aerobic tank is subjected to cyclone sorting to return the sorted high-active components to the anoxic tank circulation, and the low-active components are discharged to the nearest location. Oxygen pool.

In a preferred embodiment, in step (i), the sedimented and concentrated sludge of the secondary settling tank is lifted by the existing sludge return pump and sent to the sludge return separation cyclone for cyclone separation treatment, wherein , The pressure drop loss during the sorting process does not exceed 0.05MPa.

In another preferred embodiment, in step (ii), the mud-water mixture at the end of the aerobic tank is lifted by the existing internal reflux pump and sent to the internal reflux separation and activation cyclone for cyclone separation treatment , Among them, the pressure drop loss during the sorting process does not exceed 0.03MPa.

In another preferred embodiment, in step (i), the split ratio of the sludge reflux separation is set by maintaining the existing sludge discharge, that is, the overflow of the cyclone separation is used as the excess sludge to be discharged. , The overflow flow is the same as the remaining sludge discharge volume required by the biochemical tank, and can be adjusted according to the needs of the biochemical tank.

In another preferred embodiment, in step (ii), the split ratio of the internal reflux sorting activation is maintained at 3-5%, that is, 3-5% of the overflow in the swirling process is discharged into the nearest aerobic tank At the end, the remaining part is returned to the front part of the hypoxic pool.

In another preferred embodiment, in step (i), the sludge reflux sorting reduces the sludge volume index SVI of the biochemical tank by at least 15%; in step (ii), the internal reflux sorting activates The volatile matter ratio VSS/SS (VSS: volatile suspended solids; SS: total suspended solids) index in the biochemical pool is increased by at least 10%.

In another aspect, the present disclosure provides a sludge cyclone separation and activation treatment device, which includes:

The sludge return sorting cyclone is used to carry out step (i) the sludge return sorting: the sludge is subjected to a cyclone sorting process, so that the inorganic matter in the sludge is discharged as the remaining sludge, and the active ingredients are returned to The biochemical tank, wherein the biochemical tank includes an anoxic tank and an aerobic tank; the underflow port of the sludge return sorting cyclone is connected to the front section of the anoxic tank; the overflow port is used to discharge the remaining sludge; and

The internal reflux sorting and activation cyclone is used to perform step (ii) the internal reflux sorting activation: the mud-water mixture at the end of the aerobic tank is subjected to a cyclone sorting process to return the sorted highly active components to The anoxic tank is circulated, and the low-active components are discharged to the aerobic tank nearby.

In a preferred embodiment, the device further includes:

A sludge return pump connected to the inlet of the sludge return sorting cyclone, the inlet of the sludge return pump is connected to the bottom of the second settling tank, and the top of the second settling tank is connected to the end of the aerobic tank; and

An internal reflux pump connected to the inlet of the internal reflux sorting and activation cyclone, and the inlet of the internal reflux pump is connected to the end of the aerobic tank.

In another preferred embodiment, the internal reflux sorting activation cyclone and the sludge reflux sorting cyclone both adopt a single inlet cyclone with a lightweight dispersed phase structure, and the tangential inlet aspect ratio is 2 :1, all made of polyurethane material.

In another preferred embodiment, the cone angle of the internal reflux separation and activation cyclone is 15-20 degrees, and the cone angle of the sludge return separation and activation cyclone is 6-10 degrees.

Beneficial effects:

The invention realizes directional sludge discharge, improves the settling and dewatering properties of activated sludge, and improves the activity of sludge. Compared with the existing return sludge separation technology, the present invention has the following advantages:

Process equipment: Compared with other processes, it has not caused major process changes; in addition, the cyclone also has the advantages of no moving parts, simple structure, low equipment cost, and convenient maintenance.

Energy consumption: Compared with other sludge separation and activation technologies, the energy consumption cost is greatly reduced.

Operating range and stability: the cyclone device and operation are simple, and it is effective for sludge flocs of different particle sizes; in addition, the cyclone separation is a mechanical separation, which does not affect the stable operation of the system.

Description of the drawings

The accompanying drawings are used to provide a further understanding of the present disclosure, and they only constitute a part of the specification to further explain the present disclosure, and do not constitute a limitation to the present disclosure.

Fig. 1 is a flowchart of a sludge cyclone separation and activation treatment method according to a preferred embodiment of the present disclosure.

Fig. 2 is a schematic structural diagram of a cyclone according to a preferred embodiment of the present disclosure.

Detailed ways

After extensive and in-depth research, the inventor of the present application found that for a long time, the remaining sludge formed by the activated sludge process represented by the anoxic/aerobic denitrification process was just discharged without distinction. It has not been screened, that is, the discharged sludge contains sludge with good biochemical properties, which not only causes potential environmental pollution, increases treatment costs, and wastes resources. The use of a specific cyclone separation method to discharge sludge can eliminate sludge with poor settling performance, so that sludge settling performance is improved, the degradation efficiency of the biochemical tank is improved, and the remaining sludge output is reduced, thereby solving the above-mentioned problems. There are long-term problems in technology. Based on the above findings, the present invention has been completed.

In the first aspect of the present disclosure, there is provided a sludge cyclone separation and activation treatment method, which includes the following steps:

(a) Sludge return sorting: the concentrated sludge in the secondary settling tank is lifted by the existing sludge return pump and sent to the sludge return sorting cyclone for sorting treatment, and the inorganic matter in the sludge is used as the remaining The sludge is directionally discharged, and the active ingredients are returned to the biochemical tank; and

(b) Internal reflux sorting and activation: the mud-water mixture at the end of the aerobic tank of the biochemical tank is lifted by the existing internal reflux pump and sent to the internal reflux sorting and activation cyclone for directional sorting treatment, with high active components Return to the anoxic tank cycle of the biochemical tank, and the low-active components are discharged to the end of the aerobic tank.

In this disclosure, the returned sludge is lifted by the sludge return pump and then enters the sludge return sorting cyclone, most of the activated sludge is returned to the front stage of the anoxic tank, and a small amount of inorganic matter is returned as the remaining sludge through the sludge. The overflow port of the sorting cyclone is discharged outside, and the discharge flow rate is also adjusted accordingly by the overflow valve of the mud return sorting cyclone; at the same time, the internal return liquid is lifted by the internal return pump and enters the internal return sorting and activation swirl Most of the activated sludge is returned to the front stage of the anoxic tank, a small amount of sludge is discharged into the aerobic tank nearby, and the flow distribution of the sorting and activation process is adjusted by the corresponding valve.

In the present disclosure, the sludge return sorting cyclone and the internal return liquid sorting and activation cyclone utilize head loss to power the sorting process, and mix the return sludge and muddy water with suspended matter and volatile matter in the return fluid. Separation of sexual suspended matter, thereby increasing the number of microorganisms in the sludge and sedimentation.

In the present disclosure, according to the difference in the processing capacity of the biochemical tank, the internal return fluid sorting activation cyclone and the sludge return sorting cyclone can be connected in parallel to meet the actual internal return fluid and return sludge processing capacity requirements on site.

In the present disclosure, in step (a), the sludge return sorting is realized by using an existing sludge return pump, and the pressure drop loss during the sorting process does not exceed 0.05 MPa, for example, 0.04 MPa.

In the present disclosure, in step (b), the split ratio of the internal return flow sorting activation is set by maintaining the existing sludge discharge volume, that is, the swirling sorting overflow is used as the surplus sludge discharge (external discharge). The split ratio is, for example, 6%), the overflow flow rate is the same as the remaining sludge discharge volume required by the biochemical tank, and can be adjusted accordingly according to the requirements of the biochemical tank.

In the present disclosure, in step (b), the split ratio of the internal reflux sorting activation is maintained at 3-5%, that is, 3-5% of the overflow in the swirling process is discharged into the end of the aerobic tank, and the remaining part Return to the front section of the hypoxia pool.

In the present disclosure, in step (b), the internal reflux sorting activation adopts the existing internal reflux pipeline and lifting system, and the pressure loss during the sorting activation process does not exceed 0.03 MPa, such as 0.02 MPa.

In the present disclosure, in step (a), the sludge reflux sorting reduces the sludge volume index SVI of the biochemical tank by at least 15%.

In the present disclosure, in step (b), the internal reflux sorting activation increases the volatile matter ratio VSS/SS (VSS: volatile solid suspended solids; SS: total suspended solids) index in the biochemical tank by at least 10% .

In a second aspect of the present disclosure, there is provided a sludge cyclone separation and activation treatment device, which includes:

Internal reflux sorting activation cyclone and mud reflux sorting cyclone, where the internal reflux sorting activation cyclone is placed after the internal reflux pump, and its overflow line and underflow line are respectively connected to the end of the aerobic tank and the lack of The front part of the oxygen tank; the sludge return sorting cyclone is placed after the sludge return pump, and its underflow pipeline is connected to the front part of the anoxic tank, and the overflow pipeline discharges the remaining sludge.

In the present disclosure, the internal reflux sorting activation cyclone and the sludge reflux sorting cyclone both adopt a single-inlet cyclone with a typical lightweight dispersed phase structure, and the tangential inlet aspect ratio is 2:1.

In the present disclosure, the cone angle of the internal reflux separation and activation cyclone is 15-20 degrees, for example, 18 degrees, and the cone angle of the sludge return separation and activation cyclone is 6-10 degrees.

In the present disclosure, both the internal reflux sorting activation cyclone and the mud reflux sorting cyclone are made of polyurethane.

Refer to the attached drawings below.

Fig. 1 is a flowchart of a sludge cyclone separation and activation treatment method according to a preferred embodiment of the present disclosure. As shown in Figure 1, the return sludge from the secondary settling tank 11 is lifted by the sludge return pump 12 and then enters the sludge return sorting cyclone 13 for sorting treatment. Most of the activated sludge is returned to the front stage of the anoxic tank 15. A small amount of inorganic matter is discharged as the remaining sludge through the overflow port of the sludge return sorting cyclone 13, and the discharge flow is adjusted accordingly through the overflow port valve of the sludge return sorting cyclone 13; at the same time, the end of the aerobic tank 14 The internal reflux liquid is lifted by the internal reflux pump 16 and then enters the internal reflux sorting activation cyclone 17 for sorting treatment. Most of the activated sludge is returned to the front stage of the anoxic tank 15, and a small amount of sludge is discharged into the aerobic tank 14. The flow distribution of the sorting and activation process is adjusted by corresponding valves, including MLR (mixed liquid return); among them, the influent enters from the front part of the anoxic tank 15 and drains from the secondary settling tank 11; in the aerobic tank 14 Aeration occurs.

Fig. 2 is a schematic structural diagram of a cyclone according to a preferred embodiment of the present disclosure. As shown in Figure 2, the cyclone includes an overflow tube 21, an underflow tube 22, a column section 25, a cone section 26, an insertion section 24 located below the overflow tube 21, and a feed at the attachment of the overflow tube 21 Port 23, in the figure, D represents the diameter of the column section, θ represents the cone angle of the cone section, H represents the height of the inlet section, W represents the width of the inlet section, D ₀ represents the diameter of the overflow pipe, D _d represents the diameter of the underflow pipe, and h represents the overflow Tube insertion depth, L represents the total height, L ₁ represents the height of the column section, and L ₂ represents the height of the cone section.

Example

The present invention will be further described below in conjunction with specific embodiments. However, it should be understood that these embodiments are only used to illustrate the present invention and do not constitute a limitation on the scope of the present invention. The test methods that do not indicate specific conditions in the following examples are usually in accordance with conventional conditions, or in accordance with the conditions recommended by the manufacturer. Unless otherwise stated, all percentages and parts are by weight.

Example 1:

A/O (anoxic/aerobic) process line test of ^{1m 3} /h in a domestic sewage treatment plant.

1. Process flow

As shown in Figure 1. The return sludge and internal return fluid of the secondary settling tank are lifted by the sludge return pump and the internal return pump respectively, and then enter the cyclone. The underflow sludge after the cyclone treatment is returned to the front section of the anoxic tank, and the overflow is discharged separately. As surplus sludge or discharged into the aerobic tank nearby. After the long-period cyclone separation, the density of the sludge in the biochemical tank is continuously increased, and its adsorption, dewatering and settling properties are improved.

2. Process equipment

The key equipment in this process is the cyclone, and its structure is shown in Figure 2.

3. Operation control

The operation process of the A/O experimental device: the concentration of sludge in the tank is controlled at about 3000mg/L, the residence time of the sewage in the biochemical tank is 12 hours, the ratio of internal reflux and sludge reflux are 350% and 50%, respectively, and dissolved in 3 aeration tanks. The oxygen concentration is 4mg/L, 3mg/L and 2mg/L, respectively.

4. Running results:

The temperature of the treated wastewater is normal temperature, the pH is 6.8-7.2, and the specific content is shown in Table 1. After the new A/O denitrification process reaction, COD (chemical oxygen demand) ≤50mg/L, ammonia nitrogen ≤3mg/L, total nitrogen ≤20mg/L, the overall degradation efficiency of the biochemical pool is improved compared with the traditional process.

5. Technical effect

a. Sorting the sludge

For a long time, the surplus sludge formed by the activated sludge process represented by the A/O denitrification process is just discharged indiscriminately without being screened, that is, the discharged sludge contains biochemical properties. Good sludge. In this cyclone sorting, the sludge with poor sedimentation performance is eliminated. The sedimentation performance of the sludge is improved, the degradation efficiency of the biochemical tank is improved, and the remaining sludge output is reduced. Compared with the existing return sludge separation technology, the present invention has the following advantages:

In terms of process equipment: Cyclone separation can achieve the purpose of sludge separation only by adding a cyclone to the pipeline returning from the end of the aerobic tank to the anoxic tank. Compared with other processes, it does not cause a large process. Reform; In addition, the cyclone also has the advantages of no moving parts, simple structure, low equipment cost, and convenient maintenance.

Energy consumption: Compared with the traditional process, the increased energy consumption of the present invention is mainly the energy consumption of the pump supporting the function of the cyclone. Compared with other sludge separation and activation technologies, the energy consumption cost is greatly reduced.

Operating range and stability: The cyclone device and operation are simple, and it is effective for sludge flocs of different particle sizes. In addition, the cyclone separation is a mechanical separation, which can be adjusted online through the cyclone inlet and outlet valves. The intensity of flow sorting does not affect the stable operation of the system.

The above-listed embodiments are merely preferred embodiments of the present disclosure, and are not used to limit the scope of implementation of the present disclosure. That is to say, all equivalent changes and modifications made based on the content of the patent scope of this application should be within the technical scope of this disclosure.

All documents mentioned in this disclosure are cited as references in this application, as if each document was individually cited as a reference. In addition, it should be understood that after reading the above teaching content of the present disclosure, those skilled in the art can make various changes or modifications to the present disclosure, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

A sludge cyclone separation and activation treatment method, the method includes the following steps:

(i) Sludge backflow sorting: the sludge is subjected to cyclone sorting treatment, so that the inorganic matter in the sludge is discharged as the remaining sludge, and the active ingredients are returned to the biochemical tank, wherein the biochemical tank includes anoxic Pool and aerobic pool; and

(ii) Internal reflux sorting activation: the mud-water mixture at the end of the aerobic tank is subjected to cyclone sorting to return the sorted high-active components to the anoxic tank circulation, and the low-active components are discharged to the nearest location. Oxygen pool.
The method according to claim 1, characterized in that, in step (i), the second settling tank sedimentation and concentrated sludge is lifted by the existing sludge return pump and sent to the sludge return sorting cyclone for swirling Sorting treatment, where the pressure drop loss during the sorting process does not exceed 0.05 MPa.
The method according to claim 1, characterized in that, in step (ii), the mud-water mixture at the end of the aerobic tank is lifted by the existing internal reflux pump and sent to the internal reflux separation and activation cyclone for rotation Flow sorting treatment, where the pressure drop loss during the sorting process does not exceed 0.03MPa.
The method according to claim 1 or 2, characterized in that, in step (i), the split ratio of the sludge return sorting is set by maintaining the existing sludge discharge volume, that is, the swirl sorting overflow As the surplus sludge is discharged outside, the overflow flow rate is the same as the sludge discharge volume required by the biochemical tank, and can be adjusted according to the needs of the biochemical tank.
The method according to claim 1 or 3, characterized in that, in step (ii), the split ratio of the internal reflux sorting activation is maintained at 3-5%, that is, the overflow of 3-5% in the swirling process Discharge into the end of the aerobic tank nearby, and return the remaining part to the front section of the anoxic tank.
The method of claim 1, wherein in step (i), the sludge return sorting reduces the sludge volume index SVI of the biochemical tank by at least 15%; in step (ii), the internal return The sorting activation increases the volatile content in the biochemical pool by at least 10% compared to the VSS/SS index.
A sludge cyclone separation and activation treatment device, the device comprising:

The sludge return sorting cyclone (13) is used to carry out step (i) sludge return sorting: the sludge is subjected to a cyclone sorting process, so that the inorganic matter in the sludge is discharged as the remaining sludge, and the activated The components are returned to the biochemical tank, where the biochemical tank includes an anoxic tank (15) and an aerobic tank (14); the bottom flow port of the mud return sorting cyclone (13) and the anoxic tank (15) Front connection; drain excess sludge outside the overflow; and

The internal reflux sorting and activation cyclone (17), whose underflow port is connected to the front part of the anoxic tank (15), is used to perform step (ii) the internal reflux sorting and activation: the muddy water mixture at the end of the aerobic tank is rotated Flow sorting process to return the separated high-active components to the anoxic tank circulation, and the low-active components to the nearest aerobic tank.
8. The device of claim 7, wherein the device further comprises:

The sludge return pump (12) connected to the inlet of the sludge return sorting cyclone (13), the sludge return pump inlet (12) is connected to the bottom of the second settling tank (11), the second settling tank (11) The top is connected to the end of the aerobic tank (14); and

An internal reflux pump (16) connected with the inlet of the internal reflux sorting and activation cyclone (17), and the inlet (16) of the internal reflux pump is connected with the end of the aerobic tank (14).
The device according to claim 7 or 8, characterized in that the internal reflux sorting activation cyclone (17) and the mud reflux sorting cyclone (13) both adopt a single inlet cyclone with a light dispersed phase structure. The flow device has a 2:1 aspect ratio at the tangential entrance, all made of polyurethane.
The device according to claim 7 or 8, characterized in that the cone angle of the internal reflux separation and activation cyclone (17) is 15-20 degrees, and the sludge return separation and activation cyclone (13) has a cone angle of 15-20 degrees. The cone angle is 6-10 degrees.