Sludge granulation device based on coupling of iron-carbon, mesh retention and drying and recycling, and method

Abstract

The present invention belongs to the technical field of biological treatment of wastewater, and relates to a sludge granulation device based on coupling of iron-carbon, mesh retention and drying and recycling, and a method. The sludge granulation device comprises a cylinder body, a feeding and discharging system, a variable-speed stirring system, an automated control system and a composite packing system. The feeding and discharging system comprises a feeding opening and an overflow opening on the top of the cylinder body and a discharging opening on the bottom of the cylinder body. The stirring system comprises a variable-frequency motor used for stirring sludge and a stirring rod capable of bearing packings. The automated control system comprises a controller used for regularly regulating the rotating speed, rotation direction and running time of a stirrer and valves of the feeding and discharging system. The composite packing system comprises plastic ball packing covers fixed to the stirring rod and a mesh packing and an iron-carbon packing placed therein. The present invention has a simple structure and can achieve automated control-based operation; lightweight activated sludge is subjected to mesh retention, iron-carbon crystal nucleus stress and drying-induced agglomeration, so as to form aggregates having different particle sizes and degrees of compactness, which are returned into a biochemical reaction tank, thereby promoting formation of granular sludge.

Description

A sludge granulation device and method for iron-carbon coupled mesh interception and drying return Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and in particular relates to a sludge granulation device and method for intercepting and drying sludge by an iron-carbon coupled mesh. Background Art

[0002] Aerobic granular sludge technology is a new and highly promising biological wastewater treatment technology. It offers advantages such as good settling properties, a dense structure, high biomass, tolerance to high organic loads and toxic and hazardous substances, and the ability to achieve simultaneous nitrification and denitrification. The formation of aerobic granular sludge often depends on multiple factors, including selective pressure, culture medium type and organic load, hydraulic shear force, reactor configuration, inoculum sludge, metal ions, and aggregates. The "nucleation theory" is currently one of the most important theories of granular sludge formation.

[0003] Reports indicate that there are currently over 100 wastewater treatment plants worldwide that utilize aerobic granular sludge processes, with some even reportedly using this technology in Zhejiang. However, these plants generally have high COD levels and utilize sequencing batch reactors. For some low-concentration municipal wastewater treatment plants or rural wastewater treatment facilities, particularly those using continuous-flow processes, the formation and stable operation of aerobic granular sludge remain challenges. To overcome this bottleneck, effective equipment and strategies are urgently needed to ensure the formation and stability of granular sludge.

[0004] Summary of the Invention

[0005] In response to the problems existing in the above background, the present invention provides a sludge granulation device and method with iron-carbon coupled mesh interception and drying and return. The activated sludge rapid granulation equipment has a simple structure and can realize automatic control operation. Through mesh interception, iron-carbon crystal nucleus coercion, and drying and aggregation of light activated sludge, aggregates are formed and returned to the biochemical reaction tank, thereby promoting the formation of aerobic granular sludge and enhancing the removal of pollutants.

[0006] The present invention provides a sludge granulation device with iron-carbon coupled mesh interception and drying and re-feeding, comprising: a cylinder, an inlet and outlet system, a variable-speed stirring system, an automatic control system, and a composite filler system. The inlet and outlet system includes a feed port and overflow port at the top of the cylinder, and a discharge port at the bottom of the cylinder; the stirring system includes a variable-frequency motor for sludge stirring and a stirring rod for carrying filler; the automatic control system includes a controller for timing the mixer's speed, direction, operating time, and valves of the inlet and outlet systems; and the composite filler system includes a plastic ball filler cover fixed to the stirring rod, and mesh filler and iron-carbon filler filled inside.

[0007] Preferably, the mesh filler is a polyurethane biofiller, and the iron-carbon filler is an iron shavings filler. The iron shavings are wrapped in the polyurethane biofiller and fixed with a plastic ball filler cover. The dense mesh structure of the polyurethane biofiller can effectively intercept lightweight flocs, and the iron shavings wrapped in the polyurethane can produce [H], ·OH, Fe in water micro-electrolysis. 2+ , Fe 3+ and Fe minerals, which are beneficial substances that promote granulation, while stimulating microorganisms to secrete EPS, and promoting microbial aggregation to form aggregates by bridging with EPS.

[0008] Preferably, the filling system is centered on the stirring rod, and the composite filler is connected by cable ties to form a cylindrical filling module according to the diameter and height of the cylinder, with a distance of 5 to 10 cm reserved between the filling module and the cylinder.

[0009] In addition, the present invention also provides a sludge granulation treatment method with iron-carbon coupled mesh interception and drying and returning, which is to use any of the above-mentioned sludge granulation devices with iron-carbon coupled mesh interception and drying and returning to quickly granulate activated sludge.

[0010] Preferably, the sludge granulation treatment method with iron-carbon coupled mesh interception and drying and re-feeding comprises the following steps:

[0011] (1) Slow stirring and sludge interception: according to the location of the equipment installation, use a pump to extract the activated sludge from the biochemical pool or the light sludge selected by the continuous flow dual-zone sedimentation tank and sequencing batch reactor, and stir slowly in the forward direction at a speed of 5-10r / min while feeding the sludge;

[0012] (2) Slow drainage: After continuous mud feeding for a period of time, stop feeding mud and stirring at the same time, and control the bottom discharge valve to drain slowly;

[0013] (3) Sludge drying: After the sludge is discharged, let it stand for a period of time, and then slowly stir it in a forward direction at a speed of 3 to 5 r / min to dry the sludge;

[0014] (4) Reverse rapid stirring separation: Continuously feed sludge from the feed port again. When the sludge overflows from the overflow port of the device, it is rapidly reverse stirred at a speed of 120-150 r / min. The dried sludge aggregates are separated by centrifugal force, and the generated aggregates are returned to the biochemical pool;

[0015] (5) Taking steps (1) to (4) as a cycle, the automatic operation of the device is achieved through the regulation of the automatic control system.

[0016] As a further preference, in step (1), the sludge feeding time can be 10 to 14 hours according to the sludge concentration of the sludge. The sludge concentration is greater than 1000 mg / L. When the sludge concentration is too high, the sludge feeding time can be appropriately shortened.

[0017] As a further preference, the sludge discharge time in step (2) is controlled within 30 to 60 minutes;

[0018] As a further preference, the drying time in step (3) is 8 to 12 hours according to the on-site temperature;

[0019] As a further preference, the rapid stirring time in step (4) is 1 h.

[0020] The principle of this invention is to use the dense network structure of the mesh filler to intercept light activated sludge. During the sludge feeding period, the slow stirring of the mixer and the continuous squeezing of the water flow cause sufficient collision of the light sludge in the polyurethane mesh pores, promoting sludge aggregation. In addition, the light sludge will form aggregates of different shapes and sizes in the gaps with filamentous bacteria as the skeleton and EPS as the binder; the addition of iron carbon can promote the formation of aggregates, and the micro-electrolysis process of the iron shavings wrapped in the polyurethane can produce [H], ·OH, Fe 2+ 、Fe 3+ and iron-containing minerals and other favorable substances that promote granulation: Fe 2+ 、Fe 3+ Its by-products can serve as nuclei for microbial attachment and growth, allowing granular sludge to form rapidly; OH can serve as the driving force for the formation and stable operation of aerobic granular sludge; Fe 2+ and Fe 3+ It is a metal cation with a positive charge, while the cell surface is negatively charged. It aggregates through electrical neutralization and stimulates microorganisms to secrete EPS. The return of sludge drying can quickly form aggregates and promote the formation of granular sludge. The activated sludge will secrete a large amount of EPS after natural drying, which will promote the sludge to coagulate and form aggregates. The formed aggregates are returned to the reactor. Some larger aggregates gradually form compact granular sludge under the action of hydraulic shear force and aeration, while smaller aggregates can act as the core or carrier of granular sludge to induce microbial attachment and growth, and assist in rapid sludge granulation.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention integrates technologies such as iron-carbon, mesh interception and drying and re-return to promote the granulation of activated sludge into equipment, and develops a sludge granulation device suitable for low-concentration sewage. By mesh interception, iron-carbon crystal nucleus coercion and drying and aggregation of light sludge or activated sludge in biochemical tanks selected by continuous flow dual-zone sedimentation tanks and sequencing batch reactors, aggregates are formed and re-returned to the biochemical reaction tank, thereby promoting the formation of aerobic granular sludge and enhancing the removal of pollutants. At the same time, the automatic operation of the equipment is realized through the automatic control system.

[0023] Description of the attached figures and tables

[0024] In order to more clearly illustrate the embodiments of the present invention, the following drawings will be described:

[0025] FIG1 is a schematic diagram of the overall structure of a sludge granulation device with iron-carbon coupled mesh interception and drying and re-feeding according to an embodiment;

[0026] Figure 2 is a schematic diagram of an iron-carbon-mesh composite filler and its arrangement;

[0027] FIG3 is a comparison of microscope photos of the incoming mud a and the output aggregate b in the embodiment.

[0028] Description of the accompanying drawings: cylinder 1, feed port 2, overflow port 3, discharge port 4, frequency conversion motor 5, stirring rod 6, controller 7, iron carbon-polyurethane composite filler 8, plastic ball filler cover 9, iron shavings filler 10, polyurethane filler 11. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Those skilled in the art will be able to implement the practical application of the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only a portion of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0030] Example 1

[0031] 1 and 2 , a sludge granulation device with iron-carbon coupled mesh interception and drying and return in this embodiment includes: a cylinder 1 , a feeding and discharging system, a variable speed stirring system, a filling system and an automatic control system.

[0032] The feeding and discharging system includes a feeding port 2 and an overflow port 3 located at the top of the cylinder 1 and a discharging port 4 located at the bottom of the cylinder; the stirring system includes a variable-speed, forward and reverse frequency-converting motor 5 for stirring the sludge and a stirring rod 6 that can be used to carry fillers; the automatic control system includes a controller 7 for automatically adjusting the speed, direction and running time of the mixer and the valves of the feeding and discharging system, and realizes the automatic operation of the equipment by regularly adjusting the valves of the feeding port 2 and the discharging port 4 and the running time and speed of the frequency-converting motor 5; the filling system includes a plastic ball filling cover 9 fixed on the stirring rod and a polyurethane filler 10 and iron shavings filler 11 filled inside. The diameter of the plastic ball filling cover 9 is 10 cm. Each plastic ball filling cover 9 contains 8-10 polyurethane biological fillers 10 with a specification of 2.5*2.5*2.5 cm and 10-15g iron shavings filler 11. The polyurethane filler 10 wraps the iron shavings filler 11 and is fixed with the plastic ball filling cover 9 to form an iron-carbon-polyurethane composite filler 8. The composite fillers 8 are fixed to the stirring rod 6 layer by layer with 22 fillers per layer, for a total of 5 layers. The fillers are closely connected to each other, which is conducive to intercepting the light activated sludge.

[0033] The present embodiment provides a sludge granulation treatment method with iron-carbon coupled mesh interception and drying and re-feeding, comprising the following steps:

[0034] (1) Slow stirring and sludge interception: The activated sludge from the biochemical reaction tank in the 20t / d oxidation ditch device is continuously pumped into the cylinder 1 from the feed port 2. The sludge concentration in the biochemical reaction tank is 4000mg / L. The flow rate and the valve of the discharge port 4 are controlled so that the sludge submerges the filler. The sludge from the overflow port 3 and the discharge port 4 is discharged back into the biochemical reaction tank. While the sludge is being fed, slow forward stirring is performed at a speed of 5-10r / min for 10 hours.

[0035] (2) Slow drainage: After continuous mud feeding for 10 hours, stop feeding mud and stirring at the same time, and control the valve 4 of the discharge port to allow slow drainage for 1 hour.

[0036] (3) Sludge drying: After the slow drainage is completed, let it stand for 30 minutes, and then slowly stir it in a forward direction at a speed of 3-5 r / min to dry the sludge for 10 hours.

[0037] (4) Reverse rapid stirring and separation: Sludge is continuously fed from the feed port 2 again. When the sludge overflows from the overflow port 3 of the device, the variable frequency motor 5 is started at a speed of 120-150 r / min to perform rapid reverse stirring. The dried sludge aggregates are separated by centrifugal force. The generated aggregates are returned to the biochemical tank along with the sludge.

[0038] The light sludge a selected by pressure screening in the dual-zone sedimentation tank and the aggregate b produced in the embodiment are shown in Figure 3. The light sludge is intercepted by mesh, coerced by iron-carbon crystal nuclei, and aggregated by drying to form aggregates of different particle sizes and densities. The particle size of the output aggregates is mainly distributed between 50 and 200 μm. After being returned to the biochemical tank, it can effectively accelerate the formation of granular sludge.

[0039] Example 2

[0040] The aggregate yield of the equipment was determined by implementing the iron-carbon coupled mesh interception and drying and re-feeding sludge granulation device described in 1. The specific test method is as follows:

[0041] The light sludge selectively screened by pressure in the dual-zone sedimentation tank of the 20t / d oxidation ditch device is pumped into the cylinder 1 from the feed port 2. The sludge feeding is stopped when the sludge submerges the filler module. At this time, the initial sludge concentration in the cylinder is measured to be 1252mg / L. After that, the sludge concentration in the cylinder is measured every 2h, and the concentration change difference and time data are used to calculate the amount of sludge retained by the filler. These sludge retention amounts are dried and returned, and all enter the reaction tank as aggregates. Therefore, the sludge aggregate yield is defined as: the mass of aggregates produced per unit sludge volume per unit time. According to calculations, the sludge concentrations in the cylinder at 2, 4, 6 and 8h are 1214, 1139, 1029 and 1010mg / L respectively, and the sludge aggregate yield can reach 12.3g / m 3 ·h.

Claims

1. A sludge granulation device with iron-carbon coupled mesh interception and drying return, characterized in that: include: A barrel (1), a feeding and discharging system, a variable speed stirring system, an automatic control system and a composite filler system; the feeding and discharging system comprises a feeding port (2) and an overflow port (3) located at the top of the barrel (1) and a discharge port (4) located at the bottom of the barrel; the variable speed stirring system comprises a variable frequency motor (5) for sludge stirring and a stirring rod (6) for carrying fillers; the automatic control system comprises a controller (7) for timing the adjustment of the stirring machine speed, direction and running time and for controlling the valves of the feeding and discharging system; the composite filler system comprises a plastic ball filler cover (9) fixed on the stirring rod and an iron-carbon filler (10) and a mesh filler (11) filled inside.

2. The sludge granulation device with iron-carbon coupled mesh interception and drying and return according to claim 1 is characterized in that: The variable frequency motor (5) is a motor capable of achieving variable speed adjustment, forward rotation and reverse rotation.

3. The sludge granulation device with iron-carbon coupled mesh interception and drying and re-feeding according to claim 1 is characterized in that: The automatic control system can regularly control the valve switches of the feed port (2), the discharge port (4) and the overflow port (3), as well as the speed, direction and running time of the variable frequency motor (5).

4. [Corrected 01.11.2024 according to Rule 26] A sludge granulation device with iron-carbon coupled mesh interception and drying and return according to claim 1, characterized in that: The composite filler system is centered on the stirring rod (6), and the composite filler is connected by cable ties according to the diameter and height of the cylinder (1) to form a cylindrical filler module, with a distance of 5-10 cm reserved between the filler module and the cylinder.

5. [Corrected 01.11.2024 according to Rule 26] A sludge granulation device with iron-carbon coupled mesh interception and drying and return according to claim 1, characterized in that: The iron-carbon filler (10) is an iron shavings filler, and the mesh filler (11) is a polyurethane biological filler.

6. [Corrected 01.11.2024 according to Rule 26] A sludge granulation treatment method using an iron-carbon coupled mesh interception and drying and re-feeding sludge granulation device as described in any one of claims 1 to 6, characterized in that: It can achieve rapid granulation of light activated sludge selected by pressure screening in continuous flow dual-zone sedimentation tanks, sequencing batch reactors or activated sludge in biochemical tanks.

7. [Corrected 01.11.2024 according to Rule 26] The sludge granulation method according to claim 7, characterized in that: The following steps are involved: (1) Slow stirring and sludge interception: according to the installation location of the equipment, use a pump to extract the activated sludge from the biochemical pool or the light activated sludge selected by the continuous flow dual-zone sedimentation tank and sequencing batch reactor, and stir slowly in the forward direction at a speed of 5-10r / min while feeding the sludge; (2) Slow drainage: After continuous mud feeding for a period of time, stop feeding mud and stirring at the same time, and control the bottom discharge valve to drain slowly; (3) Sludge drying: After the sludge is discharged, let it stand for a period of time, and then slowly stir it in a forward direction at a speed of 3 to 5 r / min to dry the sludge; (4) Reverse rapid stirring separation: Continuously feed sludge from the feed port again. When the sludge overflows from the overflow port of the device, it is rapidly stirred in the reverse direction at a speed of 120-150 r / min. The dried sludge aggregates are separated by centrifugal force, and the generated aggregates are returned to the biochemical tank along with the sludge. (5) Taking steps (1) to (4) as a cycle, the automatic operation of the device is achieved through the regulation of the automatic control system.

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