A method for synchronously treating sewage and concentrated sludge

Abstract

The present invention discloses a method for synchronously treating sewage and concentrated sludge, which adopts a dynamic horizontal double-shaft rotating disk ceramic membrane device. By combining centrifugal force and shear force through the rotating disk ceramic membrane, the present invention effectively weakens the formation of the filter cake layer and concentration polarization, improves the anti-pollution ability of the rotating disk ceramic membrane, and can tolerate a relatively high sludge concentration. The rotating disk ceramic membrane does not require a high membrane surface flow rate and large flow rate, and the corresponding pump and pipeline prices are relatively low. The energy consumption of rotation is lower than that of large-flow circulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and particularly relates to a method for synchronously treating sewage and concentrated sludge. Background Art

[0002] In the fields of sewage treatment and water resource utilization and regeneration, a membrane bioreactor (MBR) is a water treatment technology that combines a membrane separation unit with a biological treatment unit. It uses a membrane treatment unit to replace the secondary sedimentation tank in a traditional biological treatment process. Compared with traditional sewage treatment processes, it solves problems such as sludge loss, sludge bulking, and sludge gas production. At the same time, it has advantages such as high resistance to load shocks, small equipment footprint, low production of excess sludge, and good effluent quality. After years of development and application, MBR technology can be divided into two types: external and submerged according to the relative position of the membrane module and the biological reaction tank.

[0003] The operating flux of the submerged MBR is 10 - 25 LMH, with a low operating flux and inconvenient operation and maintenance. Compared with the submerged MBR, the external MBR has more advantages in terms of anti-pollution performance, operating stability, and operation or cleaning and replacement of membrane modules. However, it uses a large-flow circulation pump and high flow velocity to scour the surface of the organic membrane, resulting in high operating energy consumption. During the treatment process, the flow rate of sewage entering the membrane and the outlet flow rate at the concentration end are large, and the flow velocity is high. Larger-diameter and better-quality pipes and fittings need to be configured, and higher requirements are placed on the sealing performance of the joints. In addition, its general design flux is between 50 - 70 LMH and needs to be replaced every 1 - 2 years, having problems such as low flux and short lifespan. Further, for both the external MBR and the submerged MBR, if the sludge concentration is higher than a certain level, rapid pollution will occur.

[0004] The MBR technology can effectively reduce the generation of excess sludge, but the excess sludge still needs to be treated. The current concentration processes for excess sludge mainly include gravity concentration, air flotation concentration, and mechanical concentration. Among them, the designed retention time in the gravity thickener is more than 12 hours. For phosphorus-containing sludge, phosphorus release will occur due to anaerobic conditions during gravity concentration. At the same time, the supernatant of the thickener needs to be refluxed to the biochemical system, which affects the removal of phosphorus and even causes the phosphorus to exceed the standard. Air flotation concentration is suitable for concentrating light sludge such as activated sludge and biological filter beds, and can reduce the sludge moisture content from 99.5% to 94% - 96%. Its moisture content is lower than that achieved by gravity concentration, but its operating cost is high, the system is complex, and the operation and management are difficult. The mechanical concentration method is to chemically flocculate the sludge and then reduce the sludge moisture content mechanically. The problem is that a large amount of chemical agents need to be added, and the agent cost is high. Summary of the Invention

[0005] The object of the present invention is to overcome the defects of the prior art and provide a method for synchronously treating sewage and concentrating sludge.

[0006] Another object of the present invention is to provide the application of a dynamic horizontal double-shaft rotating disk ceramic membrane device in synchronously treating sewage and concentrating sludge.

[0007] The technical solution of the present invention is as follows:

[0008] A method for synchronously treating sewage and concentrating sludge, which uses a dynamic horizontal double-shaft rotating disk ceramic membrane device, comprising a horizontal rotating disk ceramic membrane unit, a feed pump, a dialysis liquid storage tank, two driving motors, and a control unit.

[0009] The horizontal rotating disk ceramic membrane unit includes a membrane unit cavity, two rotating hollow shafts, a plurality of rotating disk ceramic membranes, and two speed reducers. A first interface communicating with its inner cavity is provided at the upper part of the membrane unit cavity, and a second interface communicating with its inner cavity is provided at the lower part. The two rotating hollow shafts are horizontally arranged in the membrane unit cavity. A plurality of rotating disk ceramic membranes are hermetically sleeved in parallel on each rotating hollow shaft, and the inner cavity of the rotating hollow shaft is communicated with the internal flow channels of the plurality of rotating disk ceramic membranes. The rotating disk ceramic membranes on the adjacent two rotating hollow shafts are staggered and parallel to each other. One end of the two rotating hollow shafts penetrates through one end of the membrane unit cavity in the horizontal direction through mechanical seals. The two driving motors are arranged above the two speed reducers and are respectively drivingly connected to the two rotating hollow shafts through the two speed reducers, so that the two rotating hollow shafts rotate in the same direction.

[0010] The dialysis liquid storage tank is communicated with the inner cavities of the two rotating hollow shafts through two rotary joints. It has a feed port at the bottom and a discharge port at the top, and the feed port communicates with the two rotary joints.

[0011] The feed pump is connected to the second interface of the membrane unit cavity through a feed regulating valve. The second interface is also connected to a bottom discharge valve. A concentrate outlet regulating valve is provided at the first interface of the membrane unit cavity. The outlet of the dialysis fluid storage tank is connected to a dialysis valve and a dialysis outlet regulating valve in sequence, and is connected to an external gas source through an air inlet valve.

[0012] The control unit is controllably connected to two drive motors, an air inlet valve and a dialysis valve.

[0013] The specific steps include:

[0014] (1) Feed the remaining sludge in the feed tank into the horizontal rotating disk ceramic membrane unit through the feed pump for filtration: The drive motor drives the rotating hollow shaft to rotate through a speed reducer, and then drives several rotating disk ceramic membranes to rotate. The obtained dialysis fluid is sent into the dialysis fluid storage tank through the inner cavity of the rotating disk ceramic membrane, the inner cavity of the rotating hollow shaft and the rotary joint. The concentrate in the membrane unit cavity flows back to the feed tank through the concentrate outlet regulating valve to complete the concentration of the remaining sludge.

[0015] (2) After the filtration is completed, backwashing is carried out. Compressed air is sent into the dialysis fluid storage tank through the air inlet valve by the external gas source, so that the dialysis fluid therein backwashes several rotating disk ceramic membranes.

[0016] (3) After the backwashing is completed, soak the rotating disk ceramic membrane with an acid solution and an alkali solution to restore the initial clean water flux.

[0017] In a preferred embodiment of the present invention, the aperture of the rotating disk ceramic membrane is 100 - 500 nm.

[0018] Further preferably, the rotation speed of the rotating disk ceramic membrane is 240 - 480 RPM.

[0019] Even more preferably, the filtration and backwashing are carried out alternately. The filtration time is 8 - 12 min, and the backwashing time is 8 - 12 s.

[0020] Even further preferably, the backwashing pressure is 1 - 2 bar.

[0021] Another technical solution of the present invention is as follows:

[0022] Application of a dynamic horizontal double - shaft rotating disk ceramic membrane device in synchronously treating sewage and concentrating sludge. The dynamic horizontal double - shaft rotating disk ceramic membrane device includes a horizontal rotating disk ceramic membrane unit, a feed pump, a dialysis fluid storage tank, two drive motors and a control unit.

[0023] Horizontal Rotating Disk Ceramic Membrane Unit, comprising a membrane unit cavity, two rotating hollow shafts, a number of rotating disk ceramic membranes, and two speed reducers. The two rotating hollow shafts are horizontally arranged in the membrane unit cavity. A number of rotating disk ceramic membranes are hermetically sleeved in parallel on each rotating hollow shaft, and the inner cavity of the rotating hollow shaft is communicated with the internal flow channels of the number of rotating disk ceramic membranes. The rotating disk ceramic membranes on adjacent two rotating hollow shafts are staggered and parallel to each other. One end of the two rotating hollow shafts penetrates through one end of the membrane unit cavity in the horizontal direction through mechanical seals; two driving motors are arranged above the two speed reducers and respectively drive and connect the two rotating hollow shafts through the two speed reducers;

[0024] Dialysate storage tank, which is communicated with the inner cavities of the two rotating hollow shafts through two rotating joints, has a feed port and a discharge port, and the feed port is communicated with the above two rotating joints;

[0025] The membrane unit cavity is provided with a first interface communicating with its inner cavity at the upper part and a second interface communicating with its inner cavity at the lower part;

[0026] The feed pump is communicated with the second interface of the membrane unit cavity through a feed regulating valve. The second interface is also communicated with a bottom discharge valve. The first interface of the membrane unit cavity is provided with a concentrate outlet regulating valve. The discharge port of the dialysate storage tank is successively communicated with a dialysis valve and a dialysis outlet regulating valve, and is communicated with an external gas source through an air inlet valve;

[0027] The control unit is controlled and connected to the feed pump, two driving motors, the air inlet valve, and the dialysis valve;

[0028] The specific steps include:

[0029] (1) Feed the surplus sludge in the feed tank into the horizontal rotating disk ceramic membrane unit through the feed pump for filtration: The driving motor drives the rotating hollow shaft to rotate through the speed reducer, and then drives a number of rotating disk ceramic membranes to rotate. The obtained dialysate is sent into the dialysate storage tank through the inner cavities of the rotating disk ceramic membranes, the inner cavities of the rotating hollow shafts, and the rotating joints. The concentrate in the membrane unit cavity flows back to the feed tank through the concentrate outlet regulating valve to complete the concentration of the surplus sludge;

[0030] (2) After the filtration is completed, perform backwashing. The external gas source sends compressed air into the dialysate storage tank through the air inlet valve, so that the dialysate therein performs backwashing on a number of rotating disk ceramic membranes;

[0031] (3) After the backwashing is completed, soak the rotating disk ceramic membranes with acid solution and alkali solution to restore the initial clean water flux.

[0032] In a preferred embodiment of the present invention, the aperture of the rotating disk ceramic membrane is 100 - 500 nm.

[0033] Further preferably, the rotational speed of the rotary disk ceramic membrane is 240 - 480 RPM.

[0034] Even more preferably, the filtration and backwashing are carried out alternately. The filtration time is 8 - 12 min, and the backwashing time is 8 - 12 s.

[0035] Even further preferably, the backwashing pressure is 1 - 2 bar.

[0036] The beneficial effects of the present invention are as follows:

[0037] 1. In the existing organic tubular membrane module, a large - flow circulation pump is used to flush the membrane surface at a high flow rate to delay membrane fouling. The related pipelines and circulation pump configuration are expensive, and at the same time, the energy consumption is high, the operation flux is low, and the service life is short. In contrast, the present invention uses a dynamic horizontal double - shaft rotary disk ceramic membrane device to replace the existing organic tubular membrane module. By combining centrifugal force and shear force through the rotary disk ceramic membrane, the formation of the filter cake layer and concentration polarization are effectively weakened, the anti - fouling ability of the rotary disk ceramic membrane is improved, and it can tolerate a higher sludge concentration. The rotary disk ceramic membrane does not require a high membrane surface flow rate and large flow rate, and the corresponding pumps and pipelines are relatively inexpensive. The energy consumption of rotation is lower than that of large - flow circulation.

[0038] 2. The service life and flux of the rotary disk ceramic membrane in the present invention are greatly improved compared with the organic tubular membrane.

[0039] 3. The present invention uses the rotary disk ceramic membrane to synchronously treat sewage and directly concentrate the sludge in the membrane tank, reducing the sludge moisture content. Because the sludge moisture content is low and the sludge concentration is high after sludge concentration, the sludge return flow can be reduced to a great extent.

[0040] 4. The present invention uses a dynamic horizontal double - shaft rotary disk ceramic membrane device to synchronously carry out sewage treatment and sludge concentration. The moisture content of the concentrated sludge can reach or even be lower than the same - type technical indicators, and there are no problems of anaerobic phosphorus release in gravity concentration, operation and management problems of air - flotation concentration equipment, and problems of mechanical concentration agents.

[0041] 5. The dynamic horizontal double - shaft rotary disk ceramic membrane device in the present invention uses a double - shaft system, and the membrane sheets are staggered with each other. The staggered membrane sheets can effectively slow down the fouling of the membrane sheets near the center of the circle. The two shafts rotate in the same direction, which can increase the relative speed. To a certain extent, reducing the rotational speed can also slow down the problem of uneven fouling. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic structural diagram of the dynamic horizontal double - shaft rotary disk ceramic membrane device in Embodiment 1 of the present invention.

[0043] Figure 2 It is a filtration effect diagram at different rotational speeds in Embodiment 2 of the present invention.

[0044] Figure 3 It is a comparison chart of sludge moisture content at different rotation speeds in Embodiment 2 of the present invention.

[0045] Figure 4 It is a comparison chart of the recovery effect of cleaning methods on the pure water flux in Embodiment 2 of the present invention.

[0046] Figure 5 It is an experimental comparison chart of single-axis and double-axis in Embodiment 3 of the present invention.

[0047] Figure 6 It is a photo of a single-axis membrane sheet after being rinsed with pure water in Embodiment 3 of the present invention.

[0048] Figure 7 It is a photo of a double-axis membrane sheet after being rinsed with pure water in Embodiment 3 of the present invention. Detailed implementation manners

[0049] The technical solutions of the present invention will be further described and illustrated below through specific implementation manners in conjunction with the accompanying drawings.

[0050] Embodiment 1

[0051] As Figure 1 shown, a dynamic horizontal double-axis rotating disk ceramic membrane device includes a horizontal rotating disk ceramic membrane unit 1, a feed pump 2, a dialysate storage tank 3, two driving motors 4, and a control unit 5.

[0052] The horizontal rotating disk ceramic membrane unit 1 includes a membrane unit cavity 10, two rotating hollow shafts 11, a plurality of rotating disk ceramic membranes 12, and two speed reducers 13.

[0053] The membrane unit cavity 10 is provided with a first interface 101 communicating with its inner cavity at the upper part and a second interface 102 communicating with its inner cavity at the lower part. Both the first interface 101 and the second interface 102 are staggered from the membrane sheets of the plurality of rotating disk ceramic membranes 12 to prevent fluid impact and damage the membrane sheets of the rotating disk ceramic membranes 12. At the other end of the horizontal direction of the membrane unit cavity 10, a gland 103 is detachably covered. There is an observation window on the gland 103, and the operation status of the equipment can be directly checked through the observation window without disassembling the gland 103 to judge the operation state of the equipment. The connection and installation method between the membrane unit cavity 10 and the gland 103 can be flange installation or clamp installation, and the membrane unit cavity 10 can be cleaned or the rotating disk ceramic membranes 12 can be disassembled by quickly removing the gland 103.

[0054] Two rotating hollow shafts 11 are horizontally arranged in the membrane unit cavity 10. A number of rotating disk ceramic membranes 12 are hermetically sleeved in parallel on each rotating hollow shaft 11. An intermediate seal 111 is provided between a number of rotating disk ceramic membranes 12 on the same rotating hollow shaft 11. An outer seal 112 is provided at the other end of the rotating hollow shaft 11. The inner cavity of the rotating hollow shaft 11 is communicated with the internal flow channels of a number of rotating disk ceramic membranes 12. The rotating disk ceramic membranes 12 on two adjacent rotating hollow shafts 11 are staggered and parallel to each other. One end of the two rotating hollow shafts 11 penetrates through one end of the membrane unit cavity 10 in the horizontal direction through a mechanical seal 113. The mechanical seal 113 adopts an internally mounted single-end face seal, which can ensure no leakage under the conditions of a pressure not less than 6 bar and a rotational speed of 500 RPM. Two drive motors 4 are arranged above the two speed reducers 13 and respectively drive and connect the two rotating hollow shafts 11 through the two speed reducers 13, so that the two rotating hollow shafts 11 rotate in the same direction;

[0055] The dialysate storage tank 3 is communicated with the inner cavities of the two rotating hollow shafts 11 through two rotary joints 30. It has a feed port 31 at the bottom and a discharge port 32 at the top. The feed port 31 is communicated with the above two rotary joints 30. When the dialysate is produced from the rotary joint 30, it will first enter and be stored at the lower end of the dialysate storage tank 3. After being filled, it overflows from the dialysate storage tank 3 and finally flows out from the discharge port 32. The general volume of the dialysate storage tank 3 is 1%-10% of the total amount of dialysis in a single filtration cycle.

[0056] The feeding pump 2 is connected to the second interface 102 of the membrane unit cavity 10 through a feed regulating valve 20. The second interface 102 is also connected to a bottom discharge valve 104. A concentrate outlet regulating valve 105 is provided at the first interface 101 of the membrane unit cavity 10. The discharge port 32 of the dialysis solution storage tank 3 is connected in sequence to a dialysis valve 33 and a dialysis outlet regulating valve 34, and is connected to an external gas source through a gas inlet valve 35. The above-mentioned feeding pump 2 can be a centrifugal pump, a diaphragm pump or a pneumatic pump. The suction range of the feeding pump 2 is 1-8 m. Its feed port 31 can suck the material into the membrane unit cavity 10 through an external hose, and the feed pressure can be adjusted by adjusting the opening of the feed regulating valve 20. There is no need to add a frequency converter or a gas source regulator to control the flow rate. The dialysis valve 33 can be a solenoid valve, but it can also be a pneumatic angle seat valve or an electric valve, etc. At the same time, the opening of the regulating valve at the discharge port 32 can also be adjusted to adjust the dialysis pressure and the filtration flux. The above-mentioned rotary joint 30 rotates 360°, can withstand a pressure of 10 bar, and the rotation speed is lower than 1000 RPM. During backwashing, the treated compressed air is connected to the discharge port 32 of the dialysis solution storage tank 3 as an external gas source. During backwashing, the gas inlet valve 35 is opened, and the compressed air will press the dialysis solution stored in the dialysis solution storage tank 3 during filtration into the rotating hollow shaft 11, and overflow from the membrane surface of the rotating disc ceramic membrane 12, and finally be discharged through the first interface 101. The pressure of the compressed air is stable at 5-8 bar, and the backwashing time can be controlled between 5-15 s. During the filtration process, the membrane unit cavity 10 inlet membrane pressure can be controlled by adjusting the opening of the concentrate outlet regulating valve 105, and at the same time, the cross-flow rate is also adjusted. During the filtration process, the opening of the concentrate outlet regulating valve 105 can be adjusted very small, but it cannot be completely closed, because during the backwashing process, the concentrate outlet regulating valve 105 is also the discharge outlet during backwashing. If it is completely closed, the pressure inside the membrane unit cavity 10 will be blocked, which will weaken the backwashing effect. During filtration and backwashing, the bottom discharge valve 104 is in a closed state. Before the membrane unit cavity 10 or the membrane of the rotating disc ceramic membrane 12 needs to be cleaned, the bottom discharge valve 104 needs to be opened first to discharge the internal retained material and reduce the generation of cleaning wastewater.

[0057] The membrane unit cavity 10 can be fixed on the mounting flange of the two speed reducers 13, and all the weights of the horizontal rotating disc ceramic membrane unit are borne by the speed reducers 13. The two speed reducers 13 are installed in parallel and can be fixed on the support platform by means of base mounting. The speed reducer 13 can be a worm and worm gear reducer with a 90° angle between the input shaft and the output shaft or a helical gear speed reducer 13 with parallel shafts. The output shaft of the speed reducer 13 is a hollow shaft. The speed ratio of the speed reducer 13 is 2.0-5.0. The driving motor 4 is a four-pole motor. The rotation speed and rotation direction of the driving motor 4 can be controlled by the frequency converter in the control unit 5, and the output rotation speed of the speed reducer 13 is controlled within the range of 0-500 RPM.

[0058] Components such as the rotating hollow shaft 11 and the rotating disk ceramic membrane 12 installed on the rotating hollow shaft 11 are relatively light in weight. The rotating hollow shaft 11 adopts a cantilever support method - it is only supported by the speed reducer 13 and passes through the hollow shaft output by the speed reducer 13. At the same time, to prevent axial displacement, a hollow shaft fixing part can be provided close to the outlet of the output shaft of the speed reducer 13. The following several methods can be used to fix the rotating hollow shaft 11: 1. The rotating hollow shaft 11 has an external thread, and the hollow shaft fixing part is in the form of a round nut; (2) The rotating hollow shaft 11 is a smooth shaft, and the hollow shaft fixing part is a smooth shaft fixing ring; (3) The rotating hollow shaft 11 is a smooth shaft, and the hollow shaft fixing part is a shrink disc.

[0059] The control unit 5 includes a controller, a frequency converter and other electrical components, and is used to control all process states of the experimental test device. The controller can adopt a Chinese-programmable time relay, which is simple to program, has a high cost performance, can realize device control, has strong expandability, and meets the system design requirements. Or PLC, PCB and other methods can also be selected for control, but the price is high and professional personnel are required for design and programming. The control unit 5 only controls the intake valve 35, the dialysis valve 33 and the drive motor 4 connected to the drive of the speed reducer 13. The intake valve 35 and the dialysis valve 33 can be selected as solenoid valves or pneumatic angle seat valves. If solenoid valves are selected, the control unit 5 is electrically connected to the intake valve 35, the dialysis valve 33 and the speed reducer 13 for control. If pneumatic angle seat valves are used, the intake valve 35 and the dialysis valve 33 can be controlled by controlling the on-off of the air path. Among them, the speed output of the speed reducer 13 can be controlled by adjusting the frequency of the frequency converter. At the same time, the control unit 5 is provided with a speed indication function. The control unit 5 can further be provided with two command buttons for starting and stopping and a potentiometer for adjusting the frequency of the frequency converter, which can control the working state, the rotating speed and the rotation direction of the system. At the same time, it can further be provided with indicator lights to respectively indicate the filtration state and the backwashing state.

[0060] The working process of this dynamic horizontal double-shaft rotating disk ceramic membrane device is as follows:

[0061] Filtration: Manually close the bottom discharge valve 104 before filtration to prevent the leakage of the feed liquid from the outlet of the bottom discharge valve 104. At the same time, check whether the feed regulating valve 20, the concentrated liquid outlet regulating valve 105 and the dialysis outlet regulating valve 34 are opened. When the device starts, the speed reducer 13 starts to rotate slowly until it is adjusted to the set speed and keeps the speed unchanged. At the same time, open the dialysis valve 33 and start the feed pump 2.

[0062] Backwashing: Close the dialysis valve 33 and the feed pump 2. Open the intake valve 35, and the external air source will press the liquid stored in the dialysis liquid storage tank 12 into the rotating hollow shaft 11, wash away the pollution on the surface of the membrane of the rotating disk ceramic membrane 12, and discharge it through the concentrated liquid upper discharge unit.

[0063] Press the start button, then the filtration and backwashing cycle runs. Press the stop button, then the dialysis valve 33, the feed pump 2, the speed reducer 13 and the air inlet valve 35 are all in the power-off stop state.

[0064] After the batch experiment, if the device needs to be cleaned, the liquid sucked from the feed port can be replaced with cleaning water to flush the rotating disc ceramic membrane 12, the feed pump 2, the rotating hollow shaft 11, the dialysate storage tank 12 and the associated valves and pipelines until the dialysate outlet and the concentrate outlet are consistent with the cleaning water. Then remove the gland 103 of the membrane unit cavity 10, continue to flush the rotating disc ceramic membrane 12, clean the retained materials in the membrane unit cavity 103, and then disassemble the rotating disc ceramic membrane 12, and perform chemical immersion cleaning on the disassembled rotating disc ceramic membrane 12.

[0065] Example 2

[0066] The dynamic horizontal dual-axis rotating disc ceramic membrane device of Example 1 was used for experiments. The experimental sewage and sludge were taken from the oxidation ditch process section of Changtai County Sanda Water Co., Ltd. All indicators were stable, SV30 was between 35-42% all year round, and the sludge moisture content was about 99.5%.

[0067] The specific steps include:

[0068] (1) The experimental sewage and sludge in the barrel are sent to the horizontal rotating disc ceramic membrane unit 1 for filtration through the feed pump 2: the driving motor 4 drives the rotating hollow shaft 11 to rotate through the reducer 13, and then drives a number of rotating disc ceramic membranes 12 to rotate, and the obtained dialysate is sent to the dialysate storage tank 3 through the inner cavity of the rotating disc ceramic membrane 12, the inner cavity of the rotating hollow shaft 11 and the rotating joint 30, and the concentrated liquid in the membrane unit cavity 10 flows back to the barrel through the concentrated liquid outlet regulating valve 105, completing the concentration of the residual sludge;

[0069] (2) After the filtration is completed, backwashing is performed. The external air source sends compressed air into the dialysate storage tank 3 through the air inlet valve 35, so that the dialysate therein backwashes the plurality of rotating disc ceramic membranes 12;

[0070] (3) After backwashing is completed, the rotating disc ceramic membrane 12 is soaked with 1% acid solution and 1% alkaline solution to restore the initial clean water flux.

[0071] The pore size of the above rotating disc ceramic membrane 12 is 500nm, and the filtering method is filtering for 10min and backwashing for 10s. During the filtering and backwashing process, the diaphragm of the rotating disc ceramic membrane 12 rotates continuously at a set speed. The backwashing method is that the dialysate storage tank 3 stores a certain amount of dialysate, and backwashing is driven by compressed air. The backwashing pressure is controlled at about 1.0-2.0bar, and the backwashing volume is about 160mL.

[0072] Adopt the batch material concentration mode, drain the dialysis fluid, and the concentrated liquid flows back to the feed tank, and the concentration of the concentrated liquid will become higher and higher. On the one hand, the sludge inside the feed tank can be concentrated, and on the other hand, the water generated by the dialysis fluid can be discharged. The turbidity of the dialysis fluid is lower than 1.0 NTU.

[0073] About 25 L of feed is used for each batch, and about 2.5 L of the remaining liquid (including 1.8 L of the dead volume of the internal cavity) remains, and the actual concentration multiple is about 10 times.

[0074] From Figure 2 it can be seen that the higher the rotation speed, the higher the operating flux, and the shorter the time required to reach the same concentration multiple. And under the operating conditions of 360 and 480 RPM, the minimum operating flux is higher than 100 LMH, far higher than that of the built-in MBR (the designed flux is generally 10 - 25 LMH) and the tubular membrane external MBR (the designed flux is generally 50 - 70 LMH).

[0075] From Figure 3 it can be seen that the moisture content of the un - concentrated sludge in each batch is about 99.5%, and the moisture content of the concentrated sludge is about 95%. The theoretical concentration multiple is (1 - 95%) / (1 - 99.5%) = 10 times, and the actual concentration multiple is consistent with the theoretical concentration multiple.

[0076] From Figure 4 it can be seen that after backwashing, the rotating disk ceramic membrane 12 with a pore size of 500 nm has a large recovery. After soaking and cleaning with 1% acid solution and 1% alkali solution, the flux of the rotating disk ceramic membrane 12 can be restored to the initial clean water flux level, and the clean water is pure water filtered by RO.

[0077] Example 3

[0078] Use the dynamic horizontal double - shaft rotating disk ceramic membrane device of Example 1 for experiments, treating the same experimental sewage and sludge as in Example 2, except that it only has one rotating hollow shaft, and other process parameters and fittings are the same as in Example 2.

[0079] After concentration by about 10 times, the comparison of the experimental fluxes is as Figure 5 .

[0080] From Figure 5 it can be seen that the operating flux of Example 2 (double - shaft) will be larger than that of this example (single - shaft). When reaching the same concentration multiple, the operating time of Example 2 is shorter than that of the single - shaft.

[0081] From Figure 6 it can be seen that during the operation of the membrane sheet in this example, the pollution is uneven, and obvious pollution rings appear. From Figure 7It can be seen that the diaphragms of the rotating disk ceramic membrane 12 in Embodiment 2 operate alternately, with less pollution and no obvious pollution ring appearing.

[0082] In summary, it can be seen that the operating flux in Embodiment 2 is higher than that in this embodiment, with less pollution and the pollution ring phenomenon eliminated. The reason is that during the single-axis rotation process, there are differences in the shear linear velocity at different radii of the diaphragm. The shear linear velocity V is related to the radius r (m) and the rotation speed n (r / s). V = 2πnr, V_inner = 2×3.14×(400 / 60)×0.076 = 3.18 m / s, V_outer = 2×3.14×(400 / 60)×0.025 = 1.05 m / s. Therefore, the difference in radius at different positions of the single axis leads to different pollution speeds. In the region where the two axes intersect alternately, the relative tangential velocity V = V_inner + V_outer = 4.23 m / s. Therefore, the dynamic horizontal two-axis rotating disk ceramic membrane device in Embodiment 1 is more resistant to pollution.

[0083] The above is only a preferred embodiment of the present invention, and thus the scope of implementation of the present invention cannot be limited thereby. That is, equivalent changes and modifications made according to the scope of the present invention patent and the content of the specification should still fall within the scope covered by the present invention.

Claims

1. A method for synchronously treating sewage and concentrated sludge, characterized in that: a dynamic horizontal double-shaft rotating disk ceramic membrane device is adopted, which includes a horizontal rotating disk ceramic membrane unit, a feeding pump, a dialysate storage tank, two driving motors and a control unit, The horizontal rotating disk ceramic membrane unit includes a membrane unit cavity, two rotating hollow shafts, a number of rotating disk ceramic membranes and two speed reducers. A first interface communicating with its inner cavity is provided at the upper part of the membrane unit cavity, and a second interface communicating with its inner cavity is provided at the lower part. The two rotating hollow shafts are horizontally arranged in the membrane unit cavity. A number of rotating disk ceramic membranes are hermetically sleeved in parallel on each rotating hollow shaft, and the inner cavity of the rotating hollow shaft is communicated with the internal flow channels of the number of rotating disk ceramic membranes. The rotating disk ceramic membranes on the adjacent two rotating hollow shafts are staggered and parallel to each other. One end of the two rotating hollow shafts penetrates through one end of the horizontal direction of the membrane unit cavity through a mechanical seal. The two driving motors are arranged above the two speed reducers and are respectively drivingly connected to the two rotating hollow shafts through the two speed reducers, so that the two rotating hollow shafts rotate in the same direction; The dialysate storage tank is communicated with the inner cavities of the two rotating hollow shafts through two rotating joints. It has a feed port at the bottom and a discharge port at the top, and the feed port communicates with the two rotating joints; The feeding pump is communicated with the second interface of the membrane unit cavity through a feed regulating valve. The second interface also communicates with a bottom discharge valve. A concentrated liquid outlet regulating valve is provided at the first interface of the membrane unit cavity. The discharge port of the dialysate storage tank is sequentially communicated with a dialysis valve and a dialysis outlet regulating valve, and is communicated with an external gas source through an air inlet valve; The control unit is control-connected to the two driving motors, the air inlet valve and dialysis; The specific steps include: (1) Feed the surplus sludge in the bucket into the horizontal rotating disk ceramic membrane unit through the feeding pump for filtration: the driving motor drives the rotating hollow shaft to rotate through the speed reducer, and then drives a number of rotating disk ceramic membranes to rotate. The obtained dialysate is sent into the dialysate storage tank through the inner cavity of the rotating disk ceramic membrane, the inner cavity of the rotating hollow shaft and the rotating joint. The concentrated liquid in the membrane unit cavity flows back to the bucket through the concentrated liquid outlet regulating valve to complete the concentration of the surplus sludge; (2) After the filtration is completed, backwashing is carried out. The external gas source sends compressed air into the dialysate storage tank through the air inlet valve, so that the dialysate therein backwashes a number of rotating disk ceramic membranes; (3) After the backwashing is completed, soak the rotating disk ceramic membrane with an acid solution and an alkali solution to restore the initial clean water flux.

2. The method according to claim 1, characterized in that: the pore diameter of the rotating disk ceramic membrane is 100 - 500 nm.

3. The method according to claim 2, characterized in that: the rotation speed of the rotating disk ceramic membrane is 240 - 480 RPM.

4. The method according to claim 3, characterized in that: the filtration and backwashing are carried out alternately. The filtration time is 8 - 12 min, and the backwashing time is 8 - 12 s.

5. The method according to claim 4, characterized in that: the backwashing pressure is 1 - 2 bar.

6. Application of a dynamic horizontal double-shaft rotating disk ceramic membrane device in synchronously treating sewage and concentrated sludge, characterized in that: The dynamic horizontal two-axis rotating disk ceramic membrane device includes a horizontal rotating disk ceramic membrane unit, a feed pump, a dialysis liquid storage tank, two driving motors, and a control unit. The horizontal rotating disk ceramic membrane unit includes a membrane unit cavity, two rotating hollow shafts, a number of rotating disk ceramic membranes, and two speed reducers. The two rotating hollow shafts are horizontally arranged in the membrane unit cavity. A number of rotating disk ceramic membranes are hermetically sleeved in parallel on each rotating hollow shaft, and the inner cavity of the rotating hollow shaft is communicated with the internal flow channels of the number of rotating disk ceramic membranes. The rotating disk ceramic membranes on adjacent two rotating hollow shafts are staggered and parallel to each other. One end of the two rotating hollow shafts penetrates through one end of the horizontal direction of the membrane unit cavity through mechanical seals; the two driving motors are arranged above the two speed reducers and are respectively drivingly connected to the two rotating hollow shafts through the two speed reducers. The dialysis liquid storage tank is communicated with the inner cavities of the two rotating hollow shafts through two rotating joints, and has a feed port and a discharge port. The feed port is communicated with the above two rotating joints. The membrane unit cavity is provided with a first interface communicating with its inner cavity at the upper part and a second interface communicating with its inner cavity at the lower part. The feed pump is communicated with the second interface of the membrane unit cavity through a feed regulating valve. The second interface is also communicated with a bottom discharge valve. The first interface of the membrane unit cavity is provided with a concentrated liquid outlet regulating valve. The discharge port of the dialysis liquid storage tank is sequentially communicated with a dialysis valve and a dialysis outlet regulating valve, and is communicated with an external gas source through an air inlet valve. The control unit is controllably connected to the feed pump, the two driving motors, the air inlet valve, and the dialysis valve. The specific steps include: (1) Send the excess sludge in the sludge tank into the horizontal rotating disk ceramic membrane unit through the feed pump for filtration: The driving motor drives the rotating hollow shaft to rotate through the speed reducer, and then drives a number of rotating disk ceramic membranes to rotate. The obtained dialysis liquid is sent into the dialysis liquid storage tank through the inner cavities of the rotating disk ceramic membranes, the inner cavities of the rotating hollow shafts, and the rotating joints. The concentrated liquid in the membrane unit cavity flows back to the sludge tank through the concentrated liquid outlet regulating valve to complete the concentration of the excess sludge. (2) After the filtration is completed, perform backwashing. The external gas source sends compressed air into the dialysis liquid storage tank through the air inlet valve, so that the dialysis liquid therein performs backwashing on a number of rotating disk ceramic membranes. (3) After the backwashing is completed, soak the rotating disk ceramic membranes with acid solution and alkali solution to restore the initial clean water flux.

7. The application according to claim 6, characterized in that: The pore diameter of the rotating disk ceramic membrane is 100 - 500 nm.

8. The application according to claim 7, characterized in that: The rotation speed of the rotating disk ceramic membrane is 240 - 480 RPM.

9. The application according to claim 8, characterized in that: The filtration and backwashing are carried out alternately. The filtration time is 8 - 12 min, and the backwashing time is 8 - 12 s.

10. The application according to claim 9, characterized in that: The pressure of the backwashing is 1 - 2 bar.

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