CN107352640B

CN107352640B - Device and method for rapid culture of aerobic granular sludge based on sludge age control

Info

Publication number: CN107352640B
Application number: CN201710571633.1A
Authority: CN
Inventors: 张智明; 俞卓栋; 朱亮; 徐向阳
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2017-07-13
Filing date: 2017-07-13
Publication date: 2023-04-25
Anticipated expiration: 2037-07-13
Also published as: CN107352640A

Abstract

The invention discloses a device and a method for quickly culturing aerobic granular sludge based on sludge age control. The device comprises a water inlet unit, a reactor main body, an aeration unit, a water discharge unit, a mud discharge unit and a control unit. The reactor main body is a columnar double-layer cylinder body, the inner cylinder body is used as a reaction area, an area between the inner cylinder body and the outer cylinder body is used as a sludge storage area, a water outlet in the inner cylinder body is connected with a sludge port of the sludge storage area through a pipeline with a first electromagnetic valve, and a sludge discharge pipe with a second electromagnetic valve is arranged at the bottom of an outer cylinder body of the sludge storage area. The invention has the characteristics of simply and effectively controlling the sludge age and reducing the occupied area of the reactor, can realize the running mode of controlling the sludge age by sludge discharge, and overcomes the problem that a Sequencing Batch Reactor (SBR) is easy to unstably under the condition of regulating and controlling the non-sludge age.

Description

Device and method for rapid culture of aerobic granular sludge based on sludge age control

Technical Field

The invention relates to a device and a method for quickly culturing aerobic granular sludge based on sludge age control, and belongs to the technical field of biological wastewater treatment.

Background

Mishima et al in 1991 found the phenomenon of autoagglomeration of aerobic activated sludge in a continuous flow AUSB reactor. The aerobic granular sludge is in a self-immobilized form of microorganisms which are spontaneously formed under the aerobic condition, has excellent sedimentation performance, higher biological retention quantity, lower sludge yield and organic load impact resistance, and greatly overcomes the defects of the traditional activated sludge method. The first aerobic granular sludge seminar held in Munich in Germany in 2005 was clearly defined, and it was considered that the aerobic granular sludge was a kind of microbial aggregate, the particles did not aggregate with the decrease of hydraulic shear force and had a faster sedimentation rate than the floc sludge, and the aerobic granular sludge technology was considered as a promising new technology for sewage treatment. Thereafter, research hotspots have focused mainly on the formation mechanism, culture conditions and major influencing factors of aerobic granular sludge and accelerated engineering applications thereof. Research reports that the retention of longer mud-age microorganisms is beneficial to the stabilization of mud particles and the efficient removal of pollutants. In the application aspect of the aerobic granular sludge technology, the universities such as Delft, queensland and the like in the Netherlands and the engineering demonstration of wastewater treatment pilot tests and engineering such as aerobic granular sludge treatment food, edible oil, beer, livestock and poultry cultivation and municipal administration are sequentially implemented. At present, the relatively mature aerobic granular sludge process is the Nereda process in the Nereda, which is a reconstruction process for construction of municipal sewage plants and the like in the Epe of the Nereda, and has the advantages of high efficiency and stability in pollutant removal, 75% land utilization and energy consumption saving.

However, the aerobic granular sludge running in the SBR reactor at present cannot be effectively controlled due to the age of sludge, so that a large amount of sludge is discharged in the running process of the reactor, thereby causing loss of functional bacterial groups, system microorganism metabolism disturbance, inhibition of nitrification and denitrification, influence on the stability of the granular structure, further causing irreversible destabilization of the reactor and restricting industrial application of the reactor. Therefore, the method can control the sludge age and simultaneously maintain the structural stability of the aerobic granular sludge and the pollutant removal efficiency, and has very important practical application significance.

Disclosure of Invention

The invention aims to provide an aerobic granular sludge device for controlling sludge age and rapidly culturing high-efficiency denitrification, which can control the sludge age of a reactor, reduce the occupied area and ensure the long-term stable operation of the aerobic granular sludge reactor.

The invention is realized by the following technical scheme:

the device for quickly culturing the aerobic granular sludge based on sludge age control comprises a water inlet unit, a reactor main body, an aeration unit and a water outlet unit; the reactor body is a columnar double-layer cylinder body, the inner cylinder body is used as a reaction area, the area between the inner cylinder body and the outer cylinder body is used as a sludge storage area, a water outlet in the inner cylinder body is connected with a sludge port of the sludge storage area through a pipeline with a first electromagnetic valve, and a sludge discharge pipe with a second electromagnetic valve is arranged at the bottom of an outer cylinder body of the sludge storage area; a porous annular plate is erected on the cross section above the sludge port of the sludge storage area and is used for reducing fluctuation of the liquid level above the plate; a first liquid level meter probe for sensing the liquid level height is arranged above the inner cylinder; a second liquid level meter probe is arranged above the porous annular plate; the aeration unit comprises an air pump, a rotameter and a porous aeration head which are connected in sequence, and the porous aeration head is positioned at the bottom of the inner cylinder; the water inlet unit and the water outlet unit are respectively used for water inlet and water outlet of the reactor main body.

Preferably, the water inlet unit comprises a submersible pump and a water inlet barrel, wherein the submersible pump is connected with the water inlet at the top of the reactor main body, and the submersible pump is positioned in the water inlet barrel.

Preferably, the water outlet unit comprises a water outlet barrel and a peristaltic pump, wherein the peristaltic pump is communicated with a water outlet on the side wall of the reactor main body and the water outlet barrel.

Preferably, a control unit is further provided for performing central control. Further, the control unit adopts a PLC controller.

Another object of the present invention is to provide a sludge age control based aerobic granular sludge rapid cultivation method using the apparatus as claimed in any one of the above, which comprises the steps of:

operating the reactor by adopting an SBR process, inoculating sludge in advance before operation, and inoculating MLSS to be 4-6g/L; the water inflow matrix is town sewage, the COD concentration of the water inflow is 300-800mg/L, and the organic load is maintained to be 1.5-3.0kg COD.m in the running process ^-3 ·d ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The reactor adopts the height-diameter ratio of 4-8 and the drainage ratio of 30% -70%; the operation period is 4-6h, and the method comprises six stages of water inlet, standing, aeration, sludge discharge, precipitation and water outlet, wherein the sludge discharge time is 1-2min, the precipitation time is 5-60min, and the aeration time is 3-5h.

Preferably, in the sludge discharge stage, the sludge discharge time point is controlled to be 1-2min before the aeration is finished, and the sludge age in the reactor is controlled to be 6-8 days, preferably 8 days. The mud discharge flow rate of the reactor can be controlled to be 80-110mL/min.

Preferably, in the precipitation stage, the precipitation time is regulated at intervals of 2-3 days according to the time required by the sludge layer to be precipitated to the height of 2-3cm below the water outlet, so that the effluent is kept in a clear state.

Preferably, the inoculated sludge is taken from an aeration tank of a municipal sewage treatment plant.

Therefore, the invention has the following beneficial effects:

(1) The device can realize the effect of controlling the sludge age in the reactor, and simultaneously, the double-cylinder structure can reduce the occupied area and remarkably improve the denitrification performance.

(2) The invention adopts the operation mode of mud discharge in the aeration stage to control the mud age, overcomes the problem that the Sequencing Batch Reactor (SBR) is easy to unstably under the condition of non-mud age regulation, and can ensure that the reactor has higher pollutant removal efficiency (the NH4 < + > -N, COD and TN removal rate are respectively maintained to be more than 90%, 95% and 75%) and stably operates for a long time.

(3) As the process control mode of controlling the mud age to be 6-8 days is adopted, compared with the traditional SBR method, the granulation time is shortened by 15-20 days, the TN removal rate is improved by 5-10%, the problems of long granulation time and easy instability of particles in the traditional SBR process are overcome, and the method has very important practical significance in actual sewage treatment.

(4) The cultured aerobic granular sludge is light yellow spherical particles, the average particle size is 0.2mm, the particle size is normal, the particle structure is compact, and the surface of the aerobic granular sludge is provided with ravines to ensure Dissolved Oxygen (DO) and nutrient mass transfer; compared with the common activated sludge, the microorganism in the granular sludge is tightly aggregated, contains a higher proportion of zoogloea, and is enriched with functional flora such as the genus of the Microsoft-shelled turtle, the genus of the ceramic, the genus of the Nitrospira and the like.

Drawings

FIG. 1 is a schematic view of an apparatus used in embodiment 1 of the present invention;

FIG. 2 is a schematic view of the structure of a porous annular plate of the present invention;

FIG. 3 is a graph of reactor sludge settling time in an example;

FIG. 4 is a graph showing changes in reactor sludge concentration (MLSS) and sludge volume index (SV) index in examples;

FIG. 5 is a graph showing the variation of contaminant removal performance of a conventional SBR process and a mud age control process in the examples;

fig. 6 is a SEM comparison of the granular sludge at different processes in the examples. a. SEM images of the surface of aerobic granular sludge in the traditional SBR process; b, carrying out SEM (scanning electron microscope) image on the surface of the aerobic granular sludge under the control condition of SRT (8 d); c, carrying out SEM image on the surface of the aerobic granular sludge under the control condition of SRT (12 d);

in the figure: the air pump 1, the rotameter 2.1, the porous aeration head 2.2, the control unit 3, the submersible pump 4, the water inlet barrel 5, the first liquid level meter probe 6, the peristaltic pump 7, the water outlet barrel 8, the second liquid level meter probe 9, the first electromagnetic valve 10, the second electromagnetic valve 11, the water outlet 12, the sludge port 13 and the porous annular plate 14.

Detailed Description

The invention will be further described with reference to the accompanying drawings and specific embodiments

The embodiment shown in fig. 1 is a device for rapid cultivation of aerobic granular sludge based on sludge age control, which integrally comprises a water inlet unit, a reactor main body, an aeration unit and a water outlet unit.

Wherein the reactor main body is a double-layer cylinder body with a cylindrical upper part and a conical lower part, the inner cylinder body is used as a reaction area, and the area between the inner cylinder body and the outer cylinder body is used as a sludge storage area, so that the occupation area of the independent sludge storage area is reduced, and the floor area of the device is saved. The water outlet 12 in the inner cylinder is connected with the sludge port 13 of the sludge storage area through a pipeline with a first electromagnetic valve 10, the bottom of the outer cylinder of the sludge storage area is provided with a sludge discharge pipe with a second electromagnetic valve 11, and the residual sludge in the sludge storage area is discharged by opening the second electromagnetic valve 11. The mud-water mixture in the aeration stage in the inner cylinder enters the sludge storage area through the water outlet 12 and the sludge opening 13, so that the sludge age in the device can be controlled by controlling the discharge amount of the mud-water mixture. The sludge discharge amount in the sludge storage area is detected by the second liquid level meter probe 9, but in the aeration stage, the sludge discharge has large hydraulic impact, and the liquid level fluctuation is easy to cause, so that a porous annular plate 14 shown in fig. 2 is erected on the cross section above the sludge opening 13 of the sludge storage area for reducing the fluctuation of the liquid level above the plate. The second level gauge probe 9 is arranged above the perforated annular plate 14. A first liquid level meter probe 6 for sensing the liquid level is arranged above the inner cylinder and is used for controlling the total wastewater amount in the inner cylinder.

The aeration unit comprises an air pump 1, a rotor flowmeter 2.1 and a porous aeration head 2.2 which are connected in sequence, wherein the porous aeration head is positioned at the bottom of the inner cylinder. The water inlet unit and the water outlet unit are respectively used for water inlet and water outlet of the reactor main body, wherein the water inlet unit comprises a submersible pump 4 and a water inlet barrel 5, which are connected with a water inlet at the top of the reactor main body, and the submersible pump 4 is positioned in the water inlet barrel 5 and is used for conveying matrixes stored in the water inlet barrel 5 into the reactor; the water outlet unit comprises a water outlet barrel 8 and a peristaltic pump 7, wherein the peristaltic pump 7 is communicated with a water outlet on the side wall of the reactor main body and the water outlet barrel 8, and is used for discharging redundant matrix wastewater in the reactor into the water outlet barrel 8.

The whole device is centrally controlled by a control unit 3, the control unit 3 can be realized by adopting a PLC controller, a singlechip and the like, and is respectively connected with an air pump 1, a rotor flowmeter 2.1, a submersible pump 4, a first liquid level meter probe 6, a peristaltic pump 7, a second liquid level meter probe 9, a first electromagnetic valve 10 and a second electromagnetic valve 11. According to each sensing device, other valves, pumps and other devices are automatically controlled, so that closed-loop control is realized.

The operation process of the device is as follows:

the reactor is operated by adopting the SBR process, matrix wastewater in the water inlet barrel 5 is pumped into the reactor main body through the submersible pump 4, sludge is inoculated at the same time, and the wastewater is aerated by the air pump 1; in the aeration phase, the sludge-water mixture is withdrawn from the reactor and stored in the sludge storage area by opening the first solenoid valve 10 1 minute before the aeration is completed. In this process, the fluctuation of the liquid level is eliminated by the perforated annular plate 14, the liquid level is monitored by the second level gauge probe 9, and when the predetermined level is reached, the operation of the first solenoid valve 10 is stopped. The second solenoid valve 11 is then opened and the sludge-water mixture is discharged. The wastewater matrix in the reactor can be quantitatively pumped into a water outlet bucket 8 through a peristaltic pump 7.

The mud discharge time is preferably 1-2min before the end of the reactor operation period, the mud age is determined by the optimal mud age of the system functional flora, and the mud discharge amount is determined by the following formula

Wherein, the liquid crystal display device comprises a liquid crystal display device,

SRT-sludge age, d

V-reactor volume, L

V' -sludge discharge volume of each cycle, L

T-reactor run period, h

The mud age of the current aerobic granular sludge SBR process cannot be effectively controlled, so that a large amount of sludge is discharged in the running process of the reactor, functional bacterial group loss is caused, the metabolism of microorganisms in the system is disturbed, the nitrification and denitrification effects are inhibited, the stability of the granular structure is affected, the irreversible destabilization phenomenon of the reactor is further caused, and the industrialized application of the reactor is restricted. Compared with the traditional SBR technology, the invention can further regulate and control the sludge age by controlling the sludge discharge, shortens the granulating time by 15-20 days, improves the TN removal rate by 5-10%, overcomes the problems of long granulating time and easy instability of particles of the traditional SBR technology, and has very important practical significance in actual sewage treatment.

The aerobic granular sludge obtained by the invention is light yellow spherical particles, the average particle size of the sludge is 0.1mm, the sludge is uniformly distributed, the particle structure is compact, and the surface of the sludge is provided with ravines to ensure Dissolved Oxygen (DO) and nutrient mass transfer. The particles have compact agglomeration of microorganisms, contain a higher proportion of zoogloea, and are enriched with functional flora such as zoogloea, terrestris, nitrosamona, nitrospira and the like.

The technical effects of the present invention will be further described by examples.

Examples

In the aerobic granular sludge treatment process for town sewage in the embodiment, a Sequencing Batch Reactor (SBR) with an effective volume of 4.0L is adopted, the main body of the reactor is a cylindrical organic glass cylinder, the height of the cylinder is 50cm, the inner diameter is 10cm, and the height-diameter ratio is 5. The specific structure of the device is shown in fig. 1 and 2 and the foregoing description, and will not be repeated.

The inoculated sludge in this example was obtained from an aeration tank of a municipal sewage treatment plant, and the shannon index was 4.85, which means that the particles had a high abundance of flora, and the gate-level flora structure analysis found that the Proteus and Bacteroides accounted for over 60%.

The operation process of the embodiment for culturing aerobic granular sludge by treating town sewage by adopting the reactor is as follows: the reactor is operated by SBR technology, and the control of the PLCThe reactor is operated according to the sequence of water inlet, standing, aeration, mud discharge, precipitation and water outlet. The initial operating conditions of the reactor were: SBR cycle 4 hours, wherein water was fed for 5 minutes, left standing for 45 minutes, aerated for 180 minutes, mud was discharged for 1 minute, settled for 5 minutes, and discharged for 5 minutes. The porous aeration head arranged at the bottom of the reactor provides a surface air velocity of 2.0cm/s and a volume exchange ratio of 50%. At the initial stage of starting a reactor, common activated floc sludge with the sludge concentration of 4.5g/L is inoculated into the reactor, urban domestic sewage with the COD concentration of 650mg/L is used as a matrix, and the organic load of 2kg COD.m is maintained in the running process ^-3 ·d ^-1 . In the aeration stage, the mud-water mixture is pumped out of the reactor by a peristaltic pump 7 1 minute before aeration is finished, the flow is 1/12L/min, and the mud age in the reactor is controlled to be 8 days. Because the property of the sludge changes during the operation, the aeration time and the sedimentation time are adjusted according to the time required for the sludge layer to sediment to the height of 2 cm to 3cm below the water outlet 12 at intervals of 2 days to 3 days, so that the effluent keeps a clear state. Gradually running until all indexes of the aerobic granular sludge in the reactor are stable, and keeping the final system settling time for 5min. For convenience of the following description, the above embodiment is denoted as R2.

Meanwhile, in order to contrast and show the effect of the invention, comparative examples R1 and R3 are synchronously arranged, wherein R1 and R2 are different in that the aerobic granular sludge is cultivated by adopting an SBR process through a traditional method, the residual sludge is discharged along with SBR effluent, and the sludge age is not controlled; r3 and R2 are different in that the mud age is controlled to be 12d.

As shown in figures 4 and 5, after the aerobic granular sludge is cultured, the sludge concentration in the reactor is maintained at 4-5g/L, the treatment effect of the reactor is stable, and the effluent quality is good. Gradient post-exposure system NH ₄ ⁺ The removal rates of N, COD and TN are respectively maintained to be above 90%, 95% and 75%, the pollutant removal efficiency is high, and the long-term operation performance is stable.

Due to the adoption of the process control mode (shown in figure 3) of mud age control, compared with the traditional SBR process, the granulation time is shortened by 15-20 days, the problems of long granulation time and easy instability of particles of the traditional SBR process are solved, and the method has very important practical significance in actual sewage treatment.

As shown in FIG. 6, the aerobic granular sludge cultured at the age of 8d in the embodiment is light yellow spherical particles with larger average particle size (the average particle size is 0.1 mm) and normal particle size distribution, the particle structure is compact, and the surface has finer ravines to ensure Dissolved Oxygen (DO) and nutrient mass transfer; compared with the common activated sludge in the traditional process, the microorganism in the granular sludge is tightly aggregated, contains a higher proportion of zoogloea, the terrestris, the nitromonas, the nitrospira and other functional flora are enriched. The culture effect of the aerobic granular sludge can be influenced even if the sludge age is too long, the granular sludge with the sludge age of 12 days in the figure has smaller particle size and a loose structure, and the sludge granulating time is about 15 days longer than that of the traditional process.

Claims

1. The rapid aerobic granular sludge culture method based on the sludge age control is characterized in that the rapid aerobic granular sludge culture device based on the sludge age control comprises a water inlet unit, a reactor main body, an aeration unit and a water outlet unit;

the reactor body is a columnar double-layer cylinder body, the inner cylinder body is used as a reaction area, an area between the inner cylinder body and the outer cylinder body is used as a sludge storage area, a water outlet (12) in the inner cylinder body is connected with a sludge port (13) of the sludge storage area through a pipeline with a first electromagnetic valve (10), and a sludge discharge pipe with a second electromagnetic valve (11) is arranged at the bottom of the outer cylinder body of the sludge storage area; a porous annular plate (14) is erected on the cross section above the sludge port (13) of the sludge storage area and is used for reducing fluctuation of the liquid level above the plate; a first liquid level meter probe (6) for sensing the liquid level height is arranged above the inner cylinder; a second liquid level meter probe (9) is arranged above the porous annular plate (14); the aeration unit comprises an air pump (1), a rotameter (2.1) and a porous aeration head (2.2) which are connected in sequence, wherein the porous aeration head is positioned at the bottom of the inner cylinder; the water inlet unit and the water outlet unit are respectively used for water inlet and water outlet of the reactor main body;

the method for rapidly culturing the aerobic granular sludge comprises the following specific steps:

operating the reactor by adopting an SBR process, inoculating sludge in advance before operation, and inoculating MLSS to be 4-6g/L; the water inflow matrix is town sewage, the COD concentration of the water inflow is 300-800mg/L, and the organic load is maintained to be 1.5-3.0kg COD ∙ m during the operation ^-3 ∙d ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The reactor adopts the height-diameter ratio of 4-8 and the drainage ratio of 30% -70%; the operation period is 4-6 hours, and the operation period is divided into six stages of water inlet, standing, aeration, sludge discharge, precipitation and water outlet, wherein the sludge discharge time is 1-2 minutes, the precipitation time is 5-60 minutes, and the aeration time is 3-5 hours;

in the sludge discharge stage, the sludge discharge time point is controlled to be 1-2min before the aeration is finished, and the sludge age in the reactor is controlled to be 6-8 days.

2. The rapid cultivation method of aerobic granular sludge based on sludge age control as claimed in claim 1, wherein the water inlet unit comprises a submersible pump (4) connected with a water inlet at the top of the reactor main body and a water inlet barrel (5), and the submersible pump (4) is positioned in the water inlet barrel (5).

3. The rapid cultivation method of aerobic granular sludge based on sludge age control as claimed in claim 1, wherein the water outlet unit comprises a water outlet barrel (8) and a peristaltic pump (7), and the peristaltic pump (7) is communicated with a water outlet on the side wall of the reactor main body and the water outlet barrel (8).

4. The rapid cultivation method of aerobic granular sludge based on sludge age control as claimed in claim 1, further provided with a control unit (3) for central control.

5. The rapid cultivation method of aerobic granular sludge based on sludge control as claimed in claim 4, wherein the control unit adopts a PLC controller.

6. The method for rapid cultivation of aerobic granular sludge based on sludge age control according to claim 1, wherein the sludge age is controlled to 8 days.

7. The method for rapid cultivation of aerobic granular sludge based on sludge age control according to claim 1, wherein in the precipitation stage, the precipitation time is adjusted at intervals of 2-3 days according to the time required for the sludge layer to be precipitated to a height of 2-3cm below the water outlet (12) so as to maintain the water outlet in a clear state.

8. The sludge age control-based aerobic granular sludge rapid culture method of claim 1, wherein the inoculated sludge is taken from an aeration tank of a municipal sewage treatment plant.