A conditioning and dehydration system for biochemical mud-water mixture and its control method

Abstract

This invention discloses a conditioning and dewatering system for a biochemical sludge-water mixture and its control method. An intermediate sludge storage tank is equipped with an ORP meter and an aeration disc. A remote control system controls the aeration of the intermediate sludge storage tank based on feedback from the ORP meter. A flocculant preparation tank is equipped with a conductivity meter. The remote control system achieves precise control of the flocculant concentration based on feedback from the conductivity meter. The intermediate sludge storage tank is connected to a biochemical tank via a pipeline equipped with a delivery pump and a flow meter, and to a mixer via a pipeline equipped with a sludge inlet pump and a flow meter. The flocculant preparation tank is connected to the mixer via a pipeline equipped with a flocculant inlet pump and a flow meter. The remote control system controls the operation of relevant pumps based on feedback from the flow meter and sludge concentration meter, delivering the sludge-water mixture and flocculant to the mixer in a precise ratio. This invention features a high degree of automation and the ability to autonomously adjust under fluctuating operating conditions, achieving adaptive control of flocculant dosage and sludge concentration.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a conditioning and dewatering system for a biochemical sludge-water mixture and its control method. Background Technology

[0002] Activated sludge process is widely used in the treatment of various types of wastewater. This technology generates a certain amount of microorganisms while degrading pollutants in the water. To ensure the stability of the microbial content in the biological treatment tank, a portion of the sludge-water mixture needs to be discharged periodically. Because the microbial content in the sludge-water mixture is low, dewatering is generally required to reduce the volume and cost of subsequent treatment (transfer and disposal). Microorganisms are relatively stable in the sludge-water mixture and are difficult to spontaneously flocify and settle. To improve the efficiency of subsequent dewatering, polyacrylamide (PAM) is generally added to the sludge-water mixture for sludge floc settling. PAM is usually added to water in a fixed ratio, dissolved and matured to form a solution, which is then pumped into the sludge-water mixture for mixing before entering the downstream dewatering equipment for dewatering.

[0003] The dosage of PAM is influenced by multiple factors, including molecular weight, cationicity, solubility and maturation, dosage concentration, sludge concentration in the sludge-water mixture, and sludge properties. The primary operating method is fixed dosing, meaning a fixed PAM concentration and flow rate. While fixed dosing requires less skill from on-site personnel, it presents challenges such as difficulty in monitoring changes in operating conditions, potentially leading to increased reagent consumption or decreased dewatering efficiency. If a non-fixed dosing method is used, the workload for on-site operators in inspections and laboratory testing increases, and adjustments to the operation still suffer from delays.

[0004] Chinese patent application 202210594859.4 discloses a sludge conditioning method. This technical solution adopts a sequential batch quantitative conditioning approach, using sequential dosing, circulating mixing, and forced stirring to adjust the sludge. However, this solution is a sequential batch conditioning method, which is only suitable for small-batch treatment and lacks monitoring of the flocculant solution. It still cannot control the amount of flocculant dissolved, nor can it adaptively adjust the flocculant concentration and dosage according to different sludge concentrations.

[0005] Chinese patent application 202311700612.7 discloses an intelligent dewatering device and control method for engineering sludge. This technical solution acquires parameters such as flow rate, density, and stirring speed through online instruments or image imaging technology, achieving coordinated control of sludge quantity, dosage, and effect. However, this solution is only suitable for plate and frame dewatering of inorganic sludge (i.e., sludge with very low microbial content), and cannot monitor the degree of PAM maturation. The overall parameter acquisition is difficult (such as first capillary water absorption time and sludge specific resistance SRF), and it is not suitable for biochemical sludge with high microbial content (microorganisms contain intracellular water and bound water that cannot be removed) and centrifugal dewatering. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the problems existing in the dewatering process of biochemical sludge, such as long-term storage and deterioration, uncertain feed concentration, concentration drift of flocculant preparation, and inaccurate dosing of reagents. It provides a conditioning and dewatering system for biochemical sludge-water mixture with a compact structure, convenient operation, high reliability, high degree of automation, and the ability to autonomously adjust under fluctuating operating conditions, as well as its control method.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A conditioning and dewatering system for a biochemical sludge-water mixture includes: a relay sludge storage tank, a flocculant preparation tank, a biochemical tank, a centrifuge, and a mixer. The relay sludge storage tank is equipped with an ORP meter and a level gauge connected to a remote control system, and also has an aeration disc connected to an external aeration fan. The remote control system controls the aeration fan to aerate the relay sludge storage tank based on data feedback from the ORP meter. The biochemical tank is equipped with a sludge concentration meter to detect the sludge concentration in the biochemical tank. The relay sludge storage tank is connected to the biochemical tank via a pipeline equipped with a transfer pump and a third flow meter. The transfer pump, sludge concentration meter, and third flow meter are all connected to the remote control system. The remote control system controls the operation of the transfer pump based on data feedback from the level gauge, sludge concentration meter, and third flow meter to automatically adjust the sludge-water mixture in the biochemical tank according to a preset quantity. The sludge is transported to a relay sludge storage tank. The relay sludge storage tank is connected to a mixer via a pipeline equipped with a sludge inlet pump and a first flow meter. The flocculant preparation tank is connected to the mixer via a pipeline equipped with a drug inlet pump and a second flow meter. The flocculant preparation tank is equipped with a conductivity meter. The sludge inlet pump, the first flow meter, the conductivity meter, the second flow meter, and the drug inlet pump are all connected to a remote control system. The remote control system controls the concentration of the flocculant in the flocculant preparation tank within a preset range based on the data feedback from the conductivity meter. The remote control system also controls the operation of the sludge inlet pump and the drug inlet pump based on the data feedback from the first and second flow meters, transporting the sludge-water mixture and the drug to the mixer in a preset ratio for uniform mixing, thus achieving autonomous adjustment of the mixing dosage of the sludge-water mixture and the drug under fluctuating operating conditions. The mixer is connected to a centrifuge via a pipeline to achieve sludge-water separation.

[0009] As a further improvement of the present invention, the intermediate sludge storage tank is equipped with a stirrer to achieve stirring of the sludge-water mixture; the upper part of the stirring shaft of the stirrer is a hollow tube, and the upper part of the stirring shaft penetrates through the top of the intermediate sludge storage tank to collect odors in the intermediate sludge storage tank.

[0010] As a further improvement of the present invention, the flocculant preparation box is composed of multiple boxes connected in series, and the penultimate box is equipped with a conductivity meter and a pH meter, and the last box is equipped with a conductivity meter. The pH meter is connected to a remote control system; the last box is connected to a mixer through a pipe with a drug inlet pump.

[0011] As a further improvement of the present invention, the output end of the centrifuge is connected to a screw conveyor and a dewatering clear liquid tank respectively. The sludge separated in the centrifuge is transported to the sludge bin by the screw conveyor, and the supernatant separated in the centrifuge is stored in the dewatering clear liquid tank.

[0012] As a further improvement of the present invention, a turbidity meter is provided on the connecting pipe between the centrifuge and the dewatering liquid tank to detect the turbidity of the supernatant; the turbidity meter is connected to a remote control system.

[0013] As a further improvement of the present invention, aeration discs are installed at intervals of 30 to 100 cm at the bottom of the relay sludge storage tank.

[0014] As a general technical concept, the present invention also provides a control method for the conditioning and dewatering system based on the above-mentioned biochemical mud-water mixture, comprising the following steps:

[0015] Step S1: The remote control system calculates the sludge discharge from the biological treatment tank based on the data fed back from the level gauge and sludge concentration meter.

[0016] Step S2: The remote control system starts the delivery pump, and the biological treatment tank delivers the mud-water mixture to the intermediate sludge storage tank. When the mud-water mixture fed back by the third flow meter reaches the preset value, the remote control system shuts down the delivery pump and calculates the sludge concentration in the intermediate sludge storage tank.

[0017] Step S3: The remote control system controls the dosage of flocculant in the flocculant preparation box based on the conductivity data fed back by the conductivity meters in the last two boxes of the flocculant preparation box, so as to achieve precise control of the flocculant concentration.

[0018] Step S4: The remote control system controls the operation of the mud pump and the chemical pump. The first flow meter and the second flow meter feed back the flow rates of the mud-water mixture and the chemical agent to the remote control system in real time, so as to ensure that the mud-water mixture and the chemical agent are delivered to the mixer in a preset ratio and mixed evenly.

[0019] Step S5: The mixture in the mixer is conveyed to the centrifuge for solid-liquid separation. The turbidity meter monitors the turbidity of the supernatant discharged from the centrifuge in real time and feeds the data back to the remote control system. The dewatered sludge separated in the centrifuge is conveyed to the sludge silo by a screw conveyor.

[0020] As a further improvement of the present invention, the control of sludge discharge in steps S1 and S2 includes:

[0021] The discharge sequence of the sludge-water mixture in the biological treatment tank is set. The discharge sequence includes two parts: time period and planned discharge amount. The time period is the discharge interval, and the planned discharge amount refers to the amount of sludge-water mixture discharged to the intermediate sludge storage tank in a single discharge. When discharge is triggered, the discharge amount is controlled according to the following formula.

[0022] Actual discharge = planned discharge + previous residue - current stock in intermediate sludge storage tank; where the current stock is calculated by measuring the remaining liquid level in the intermediate sludge storage tank using a level gauge.

[0023] Previous carryover = Previous planned emissions - Previous actual emissions;

[0024] After the sludge discharge is completed, the remote control system calculates the actual sludge concentration of the sludge-water mixture in the relay sludge storage tank according to formula (1):

[0025] MLSS 实 =(V 排 *MLSS 排 +V 存 *MLSS 存 ) / (V 排 +V 存 ) Formula (1)

[0026] MLSS 实 ----- Actual sludge concentration entering the mixer, in g / L;

[0027] V 排 ------Amount of newly discharged sludge, in cubic meters (m³) 3 ;

[0028] MLSS 排 ------Sludge concentration of newly discharged sludge, in g / L;

[0029] V 存 -----The volume of sludge stored in the intermediate sludge storage tank, in cubic meters (m³). 3 ;

[0030] MLSS 存 -----Sludge concentration of sludge retained in the intermediate sludge storage tank, in g / L;

[0031] MLSS 存 =(V1*MLSS1+V2*MLSS2) / (V1+V2) Formula (2)

[0032] MLSS 存 -----Sludge concentration of sludge retained in the intermediate sludge storage tank, in g / L;

[0033] V1 ----- The amount of sludge retained in the intermediate sludge storage tank, in meters (m). 3 ;

[0034] V2-----Amount of newly discharged sludge into the intermediate sludge storage tank, in cubic meters (m³) 3 ;

[0035] MLSS1-----Sludge concentration retained in the intermediate sludge storage tank, in g / L;

[0036] MLSS2------Concentration of newly discharged sludge into the intermediate sludge storage tank, in g / L;

[0037] The sludge concentration remaining in the intermediate sludge storage tank after the Nth time is obtained by formula (2). If the intermediate sludge storage tank is in continuous feeding and discharging condition, the average value of the sludge concentration meter in the two most recent biochemical tanks is taken as the actual sludge concentration value.

[0038] As a further improvement of the present invention, in step S3, the flocculant concentration control process includes: setting the conductivity curve and pH upper and lower limits of the flocculant at 0.5‰ to 3.5‰, wherein the pH value of the second to last chamber is used for alarm, the conductivity of the second to last chamber is used to control the dosage, and the conductivity of the last chamber is used to control the frequency of the feed pump; in step S5, if the turbidity is higher or lower than the set value twice consecutively, the remote control system issues an alarm; after 4 to 6 consecutive high-value alarms, the centrifuge automatically stops.

[0039] As a further improvement of the present invention, in step S4, the dosage of the agent is controlled according to formula (3):

[0040] Q 药 =1000*MLSS 实 *Q 泥 *D*K / (c*ρ 药 ) Formula (3)

[0041] K = A 标准 / A 实际

[0042] In the formula:

[0043] A 标准 -----Theoretical conductivity of flocculant solution, in μs / cm;

[0044] A 实际 ----- Actual conductivity measured after flocculant preparation, in μs / cm;

[0045] K------Adjustment coefficient, used to characterize the effect of flocculant solution, dimensionless;

[0046] Q 药------Flocculant dosage flow rate, in meters 3 / h;

[0047] MLSS 实 ------ Actual sludge concentration entering the mixer, in g / L;

[0048] Q 泥- ------Mixer feed flow rate, in m³ 3 / h;

[0049] D------Flocculant consumption, which is the amount of flocculant required per ton of absolutely dry sludge, in kg / t;

[0050] c------Concentration of flocculant solution; i.e., the ratio of the amount of flocculant dissolved to the weight of the flocculant solution, in ‰;

[0051] ρ 药 -----This refers to the mass of the flocculant per unit volume, expressed in kg / m³. 3 .

[0052] Compared with the prior art, the advantages of the present invention are as follows:

[0053] 1. The conditioning and dewatering system and control method for the biochemical sludge-water mixture of the present invention, wherein an ORP meter and a level gauge connected to a remote control system are installed in the intermediate sludge storage tank, and an aeration disc connected to an external aeration fan is also installed in the intermediate sludge storage tank. The remote control system controls the aeration fan to aerate the intermediate sludge storage tank according to the data information fed back by the ORP meter, preventing the sludge in the intermediate sludge storage tank from turning into anaerobic sludge; a sludge concentration meter is installed in the biochemical tank, and the remote control system controls the operation of the delivery pump according to the data information fed back by the level gauge, sludge concentration meter and flow meter, realizing the accurate delivery of the sludge-water mixture in the biochemical tank to the intermediate sludge storage tank according to a preset amount; a conductivity meter is installed in the flocculant preparation tank, and the remote control system controls the operation of the delivery pump according to the data information fed back by the conductivity meter. This system enables precise control of the flocculant concentration in the flocculant preparation tank within a preset range, ensuring the flocculant's full efficacy. The intermediate sludge storage tank is connected to the mixer via a pipeline equipped with a sludge inlet pump and a first flow meter, while the flocculant preparation tank is connected to the mixer via a pipeline equipped with a chemical inlet pump and a second flow meter. Furthermore, the sludge inlet pump, the first flow meter, the second flow meter, and the chemical inlet pump are all connected to a remote control system. Based on the data feedback from the first and second flow meters, the remote control system controls the operation of the sludge inlet pump and the chemical inlet pump, delivering the sludge-water mixture and the flocculant to the mixer in a preset ratio for uniform mixing. This allows for autonomous adjustment of the mixing and dosage of the sludge-water mixture and the flocculant under fluctuating operating conditions, improving the utilization efficiency of the flocculant and meeting the automatic sludge discharge control requirements under different biochemical sludge concentrations.

[0054] 2. The conditioning and dewatering system and control method for biochemical sludge mixture of the present invention, by setting conductivity meters in the last two boxes of the flocculant preparation box and pH meters in the penultimate box, achieves precise control of PAM agent during the maturation and addition process, and solves the problems of flocculant concentration drift and inaccurate agent addition in the traditional biochemical sludge dewatering process. Attached Figure Description

[0055] Figure 1 This is a schematic diagram illustrating the structural principle of the conditioning and dehydration system for biochemical mud-water mixture in a specific embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram of the conditioning and dehydration process of the biochemical mud-water mixture in a specific embodiment of the present invention;

[0057] Legend: 1. Intermediate sludge storage tank; 2. Flocculant preparation tank; 3. Biological treatment tank; 4. Centrifuge; 5. Screw conveyor; 6. Deodorization system; 7. Aeration blower; 8. Agitator; 9. Sludge feed pump; 10. First flow meter; 11. Transfer pump; 12. ORP meter; 13. Conductivity meter; 14. pH meter; 15. Mixer; 16. Turbidity meter; 17. Second flow meter; 18. Chemical feed pump; 19. Dewatering clear liquid tank; 20. Level gauge; 21. Sludge concentration meter; 22. Third flow meter; 23. Aeration disc. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0059] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0061] Example 1

[0062] like Figure 1 As shown, the conditioning and dewatering system for the biochemical sludge-water mixture of the present invention includes: a relay sludge storage tank 1, a flocculant preparation tank 2, a biochemical tank 3, a centrifuge 4, and a mixer 15. The relay sludge storage tank 1 is equipped with an ORP meter 12 and a level gauge 20 connected to a remote control system. The relay sludge storage tank 1 also includes an aeration disc 23 connected to an external aeration fan 7. The remote control system controls the aeration fan 7 to aerate the relay sludge storage tank 1 based on data feedback from the ORP meter 12. The biochemical tank 3 is equipped with a sludge concentration meter 21 for detecting the sludge concentration in the biochemical tank 3. The intermediate sludge storage tank 1 is connected to the biological treatment tank 3 via a pipeline equipped with a transfer pump 11 and a third flow meter 22. The transfer pump 11, sludge concentration meter 21, and third flow meter 22 are all connected to a remote control system. Based on data from the level gauge 20, sludge concentration meter 21, and third flow meter 22, the remote control system controls the operation of the transfer pump 11 to ensure that the sludge-water mixture in the biological treatment tank 3 is accurately delivered to the intermediate sludge storage tank 1 according to a preset quantity. The intermediate sludge storage tank 1 is connected to the mixer 15 via a pipeline equipped with a sludge inlet pump 9 and a first flow meter 10. The flocculant preparation tank 2 is connected to the mixer 15 via a pipeline equipped with a chemical inlet pump 18 and a second flow meter 17. The flocculant preparation tank 2 is equipped with a conductivity meter 13. The sludge pump 9, first flow meter 10, conductivity meter 13, second flow meter 17, and chemical pump 18 are all connected to a remote control system. Based on data from the conductivity meter 13, the remote control system maintains the concentration of the flocculant in the preparation tank 2 within a preset range. Based on data from the first and second flow meters 17, the remote control system controls the operation of the sludge pump 9 and the chemical pump 18, delivering the sludge-water mixture and the chemical agent to the mixer 15 for uniform mixing under fluctuating operating conditions. The mixer 15 is connected to a centrifuge 4 via a pipeline for sludge-water separation.

[0063] In this embodiment, the relay sludge storage tank 1 is a capacity adjustment tank for the sludge-water mixture, without sludge thickening and sedimentation functions. The remote control system can specifically adopt a PLC control system, which is simple in principle, convenient to operate, and provides precise control.

[0064] like Figure 1As shown, centrifuge 4 has adjustable differential speed and rotational speed. The output end of centrifuge 4 is connected to screw conveyor 5 and dewatering supernatant tank 19. The sludge separated in centrifuge 4 is transported to the sludge silo via screw conveyor 5. A sampling port with automatic opening and closing is located on the lower side of the outer casing at the bottom of the middle section of screw conveyor 5 to facilitate monitoring of sludge quality. The supernatant separated in centrifuge 4 is stored in dewatering supernatant tank 19. Furthermore, a turbidimeter 16 is installed on the connecting pipe between centrifuge 4 and dewatering supernatant tank 19 to detect the turbidity of the supernatant. The turbidimeter 16 is also connected to a remote control system, which can determine the operating status of centrifuge 4 based on the data feedback from the turbidimeter 16 and control the start and stop of centrifuge 4.

[0065] like Figure 1 As shown, a stirrer 8 is installed in the intermediate sludge storage tank 1 to achieve stirring of the sludge-water mixture. The upper part of the stirring shaft of the stirrer 8 is a hollow tube, and the upper part of the stirring shaft penetrates through the top of the intermediate sludge storage tank 1 to collect the odor in the intermediate sludge storage tank 1 and transport the odor to the deodorization system 6 through a pipeline.

[0066] Specifically, the agitator 8 can be a paddle type or a frame type, used to agitate the mud-water mixture in the intermediate mud storage tank 1 to ensure that the mud and water are continuously in a mixed state. The section of the agitator shaft that passes through the top of the tank is a hollow tube with openings on both sides to collect odors in the tank.

[0067] like Figure 1 As shown, aeration discs 23 are installed at intervals of 30-100cm at the bottom of the tank. The aeration blower 7 and aeration discs 23 are used to aerate the sludge-water mixture in the intermediate sludge storage tank 1 when there is no sludge discharge for a long time, so as to ensure that the sludge in the tank does not deform into anaerobic sludge.

[0068] In this embodiment, the agitator 8 in the relay sludge storage tank 1 operates intermittently, configured according to the sludge settling characteristics. The ORP meter 12 measures the ORP value every 1-6 hours, and the agitator 8 is started 15-30 minutes before each measurement. When the ORP value is below 50 Mv, the aeration blower 7 is started to aerate the tank, with an hourly aeration rate of 3-10 times the tank volume. The ORP value is measured 30 minutes after aeration; if it remains below 50 Mv, the aeration process is repeated. The gas introduced or generated during aeration is collected by the agitator shaft and then either deodorized or discharged.

[0069] like Figure 1 As shown, the flocculant preparation tank 2 consists of four tanks connected in series. Each tank is equipped with a stirring device and operates in a continuous water inlet and outlet mode. The penultimate tank is equipped with a conductivity meter 13 and a pH meter 14, and the last tank is equipped with a conductivity meter 13. Both the conductivity meter 13 and the pH meter 14 are connected to a remote control system. The last tank is connected to the mixer 15 through a pipe with a chemical inlet pump 18.

[0070] like Figure 2 As shown, in this embodiment, a control method for the conditioning and dehydration system based on the above-mentioned biochemical mud-water mixture is also provided, including the following steps:

[0071] Step S1: The remote control system calculates the sludge discharge amount of the biological treatment tank 3 based on the data fed back by the level gauge 20 and the sludge concentration meter 21.

[0072] Step S2: The remote control system starts the delivery pump 11, and the biological treatment tank 3 delivers the mud-water mixture to the relay sludge storage tank 1. When the mud-water mixture fed back by the third flow meter 22 reaches the preset value, the remote control system shuts down the delivery pump 11 and calculates the sludge concentration in the relay sludge storage tank 1.

[0073] Step S3: The remote control system controls the dosage of flocculant in the flocculant preparation tank 2 based on the conductivity data fed back by the conductivity meters 13 in the last two chambers of the flocculant preparation tank 2, so as to achieve precise control of the flocculant concentration. In the flocculant preparation tank 2, the flocculant is added using a screw feeder method.

[0074] Step S4: The remote control system controls the operation of the mud pump 9 and the chemical pump 18. The first flow meter 10 and the second flow meter 17 feed back the flow rates of the mud-water mixture and the chemical agent to the remote control system in real time, so as to ensure that the mud-water mixture and the chemical agent are delivered to the mixer 15 and mixed evenly according to the preset ratio.

[0075] In step S5, the mixture in mixer 15 is conveyed to centrifuge 4 for solid-liquid separation. Turbidity meter 16 monitors the turbidity of the supernatant discharged from centrifuge 4 in real time and feeds the data back to the remote control system. The dewatered sludge separated in centrifuge 4 is conveyed to the sludge bin via screw conveyor 5. Further, the allowable turbidity of the supernatant is set to 10-300 NTU. Turbidity meter 16 starts monitoring 15-30 minutes after centrifuge 4 starts, and monitors every 10-60 minutes. If the turbidity is higher or lower than the set value twice consecutively, the remote control system issues an alarm. After 4-6 consecutive high-value alarms, centrifuge 4 automatically stops.

[0076] In steps S1 and S2 of this embodiment, the control of sludge discharge includes:

[0077] Set the discharge sequence of the sludge-water mixture in biological tank 3. The discharge sequence includes two parts: time period and planned discharge amount. The time period is the discharge interval, that is, the time interval between two sludge discharges. The planned discharge amount refers to the amount of sludge-water mixture discharged to the intermediate sludge storage tank 1 in a single discharge. When discharge is triggered, the discharge amount is controlled according to the following formula.

[0078] Actual discharge = planned discharge + previous residue - current amount in intermediate sludge storage tank 1; where the current amount is calculated by measuring the remaining liquid level in intermediate sludge storage tank 1 using level gauge 20.

[0079] Previous carryover = Previous planned emissions - Previous actual emissions; previous carryover can be accumulated across emissions.

[0080] After determining the actual discharge volume, the remote control system opens the valve from biological treatment tank 3 to intermediate sludge storage tank 1 and starts the transfer pump 11. When the third flow meter 22 detects that the accumulated flow has reached the actual discharge volume, the valve closes and the transfer pump 11 stops. Each time biological treatment tank 3 discharges, the sludge concentration in the discharged sludge-water mixture is the arithmetic mean of the values ​​measured by the sludge concentration meter 21 from the previous 1 to 6 times.

[0081] After the sludge discharge is completed, the remote control system calculates the actual sludge concentration of the sludge-water mixture in the relay sludge storage tank 1 according to formula (1):

[0082] MLSS 实 =(V 排 *MLSS 排 +V 存 *MLSS 存 ) / (V 排 +V 存 ) Formula (1)

[0083] MLSS 实 ----- Actual sludge concentration entering mixer 15, in g / L;

[0084] V 排 ------Amount of newly discharged sludge, in cubic meters (m³) 3 ;

[0085] MLSS 排 ------Sludge concentration of newly discharged sludge, in g / L;

[0086] V 存 -----The volume of sludge stored in intermediate sludge storage tank 1, in cubic meters. 3 ;

[0087] MLSS 存 -----Sludge concentration of sludge retained in intermediate sludge storage tank 1, in g / L;

[0088] MLSS 存 =(V1*MLSS1+V2*MLSS2) / (V1+V2) Formula (2)

[0089] MLSS 存 -----Sludge concentration of sludge retained in intermediate sludge storage tank 1, in g / L;

[0090] V1 ----- The amount of sludge retained in intermediate sludge storage tank 1, in cubic meters (m³) 3 ;

[0091] V2-----Amount of newly discharged sludge into intermediate sludge storage tank 1, in cubic meters (m³) 3 ;

[0092] MLSS1----- The concentration of sludge retained in intermediate sludge storage tank 1, in g / L;

[0093] MLSS2------Concentration of newly discharged sludge into the intermediate sludge storage tank, in g / L;

[0094] The sludge concentration remaining in the intermediate sludge storage tank 1 after the Nth time is obtained by formula (2). If the intermediate sludge storage tank 1 is in continuous feeding and discharging condition, the average value of the sludge concentration meter 21 in the two most recent biochemical tanks 3 is taken as the actual sludge concentration value.

[0095] In step S3, the flocculant concentration control process includes: setting the conductivity curve (generally linear) and pH value (upper and lower limits only) for the flocculant at 0.5‰ to 3.5‰; and setting the pH value and conductivity range for the last two chambers. Specifically, the pH value of the penultimate chamber is only used for alarm purposes, and the conductivity is used to control the dosing screw (allowed ±10%). For every ±5% deviation, the dosing screw speed is increased by ±5 to 10% (excluding the aforementioned allowable deviation range). The conductivity of the last chamber is used to control the frequency of the dosing pump 18 (allowed ±5%).

[0096] In step S4, the dosage of the agent is controlled according to formula (3):

[0097] Q 药 =1000*MLSS 实 *Q 泥 *D*K / (c*ρ 药 ) Formula (3)

[0098] K = A 标准 / A 实际

[0099] In the formula:

[0100] A 标准 -----Theoretical conductivity of flocculant solution, in μs / cm;

[0101] A 实际 ----- Actual conductivity measured after flocculant preparation, in μs / cm;

[0102] K------Adjustment coefficient, used to characterize the effect of flocculant solution, dimensionless;

[0103] Q 药 ------Flocculant dosage flow rate, in meters 3 / h;

[0104] MLSS 实 ------ Actual sludge concentration entering mixer 15, in g / L;

[0105] Q 泥- ------Inlet flow rate of mixer 15, in m³ / s 3 / h;

[0106] D------Flocculant consumption, which is the amount of flocculant required per ton of absolutely dry sludge, in kg / t;

[0107] c------Concentration of flocculant solution; i.e., the ratio of the amount of flocculant dissolved to the weight of the flocculant solution, in ‰;

[0108] ρ 药 -----This refers to the mass of the flocculant per unit volume, expressed in kg / m³. 3 .

[0109] Example 2

[0110] In the conditioning and dewatering system for the biochemical sludge-water mixture in Example 1, this system is specifically a biochemical treatment system for high ammonia nitrogen wastewater. The sludge concentration in biochemical tank 3 is 10-20 g / L. There is no traditional secondary sedimentation tank; only a 120 m³ sedimentation tank is provided. 3 The intermediate sludge storage tank 1 is equipped with a paddle-type agitator at the top, with the agitator shaft drawing air to the biochemical deodorization system. Microporous aeration discs are arranged at the bottom of the intermediate sludge storage tank 1, with micropores spaced 50cm apart. A Roots blower with an air volume of 600 Nm³ is installed outside the intermediate sludge storage tank 1. 3 / h. The flocculant is prepared in a three-compartment unit, and the dewatering machine is a horizontal centrifuge.

[0111] The sludge concentration in biological treatment tank 3 is recorded every 12 hours. Sludge is discharged once a day, continuously, with a single discharge of 200m³. 3 The ORP value of the intermediate sludge storage tank 1 is checked every 6 hours, and the ORP value is set at 50mv. If it is lower than this value, aeration is performed for 15 minutes each time. When the tank is not turned on all day, aeration is turned on for 10 minutes.

[0112] The conductivity of the reagent was set to 120 μS / cm for 0.5‰, 236 μS / cm for 1‰, 500 μS / cm for 2‰, and 702 μS / cm for 3‰, and the curves were plotted and input into the program. The solution pH was set to 3–5, the dosage concentration was set to 1.5‰, and the deviation was allowed to be ±5% for the spiral speed increase. The absolute dry consumption was set to 27 kg / t.

[0113] The turbidity of the supernatant was set to 150-300 NTU. Turbidity meter 16 was started 20 minutes after centrifuge 4 was started, and monitoring was performed every 30 minutes.

[0114] The changes in key production indicators before and after the system was implemented are shown in Table 1.

[0115] Table 1 Comparison of Key Data Before and After System Implementation

[0116] project Before being put into use After being put into use Duty Inspection 8 people / day 2 people / day Dry reagent consumption 33~35kg / t 27.3 kg / t solids content of dewatered sludge 18.7～20.2％ 19.1～20.1％

[0117] As can be seen from Table 1, by adopting the conditioning and dewatering system in Example 1, the number of shift inspections and the amount of reagents consumed were reduced. However, the solids content of the dewatered sludge remained basically unchanged, indicating that the conditioning and dewatering system of the present invention can reduce the cost of biochemical sludge dewatering and has a high degree of automation, which reduces the labor intensity of operators.

[0118] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A conditioning and dehydration system for a biochemical mud-water mixture, characterized in that, include: The system includes a relay sludge storage tank (1), a flocculant preparation box (2), a biochemical tank (3), a centrifuge (4), and a mixer (15). The relay sludge storage tank (1) is equipped with an ORP meter (12) and a level gauge (20) connected to a remote control system. The relay sludge storage tank (1) also has an aeration disc (23) connected to an external aeration fan (7). The remote control system controls the aeration fan (7) to aerate the relay sludge storage tank (1) based on data feedback from the ORP meter (12). The biochemical tank (3) is equipped with a sludge concentration meter (21) to... Used to detect the sludge concentration in the biological treatment tank (3); the intermediate sludge storage tank (1) is connected to the biological treatment tank (3) through a pipeline with a transfer pump (11) and a third flow meter (22). The transfer pump (11), sludge concentration meter (21) and third flow meter (22) are all connected to a remote control system. The remote control system controls the operation of the transfer pump (11) based on the data information fed back by the level gauge (20), sludge concentration meter (21) and third flow meter (22) so as to realize that the sludge-water mixture in the biological treatment tank (3) is automatically transported to the intermediate sludge storage tank (1) according to the preset amount. In the sludge storage tank (1); the intermediate sludge storage tank (1) is connected to the mixer (15) through a pipe with a sludge inlet pump (9) and a first flow meter (10); the flocculant preparation tank (2) is connected to the mixer (15) through a pipe with a drug inlet pump (18) and a second flow meter (17); the flocculant preparation tank (2) is equipped with a conductivity meter (13); the sludge inlet pump (9), the first flow meter (10), the conductivity meter (13), the second flow meter (17) and the drug inlet pump (18) are all connected to a remote control system, and the remote control system is based on... According to the data information fed back by the conductivity meter (13), the concentration of the agent in the flocculant preparation box (2) is controlled within the preset range. The remote control system controls the operation of the mud pump (9) and the drug pump (18) according to the data information fed back by the first flow meter (10) and the second flow meter (17), and delivers the mud-water mixture and the agent to the mixer (15) in a preset ratio for uniform mixing, so as to realize the autonomous adjustment of the mixing amount of mud-water mixture and agent under fluctuating working conditions. The mixer (15) is connected to the centrifuge (4) through the pipeline to realize mud-water separation. The flocculant preparation box (2) is composed of multiple boxes connected in series, and the penultimate box is equipped with a conductivity meter (13) and a pH meter (14), and the last box is equipped with a conductivity meter (13). The pH meter (14) is connected to a remote control system. The last box is connected to a mixer (15) through a pipe with a drug inlet pump (18).

2. The conditioning and dehydration system for biochemical mud-water mixture according to claim 1, characterized in that, The intermediate sludge storage tank (1) is equipped with a stirrer (8) to achieve stirring of the mud-water mixture; the upper part of the stirring shaft of the stirrer (8) is a hollow tube, and the upper part of the stirring shaft penetrates through the top of the intermediate sludge storage tank (1) to collect the odor in the intermediate sludge storage tank (1).

3. The conditioning and dehydration system for biochemical mud-water mixture according to claim 1 or 2, characterized in that, The output end of the centrifuge (4) is connected to the screw conveyor (5) and the dewatering clear liquid tank (19). The sludge separated in the centrifuge (4) is transported to the sludge bin via the screw conveyor (5), and the supernatant separated in the centrifuge (4) is stored in the dewatering clear liquid tank (19).

4. The conditioning and dehydration system for biochemical mud-water mixture according to claim 3, characterized in that, A turbidity meter (16) is installed on the connecting pipe between the centrifuge (4) and the dewatering liquid tank (19) to detect the turbidity of the supernatant; the turbidity meter (16) is connected to a remote control system.

5. The conditioning and dehydration system for biochemical mud-water mixture according to claim 1 or 2, characterized in that, The bottom of the intermediate sludge storage tank (1) is equipped with aeration discs (23) at intervals of 30-100cm.

6. A control method for a conditioning and dehydration system based on any one of claims 1 to 5 of a biochemical mud-water mixture, characterized in that, Includes the following steps: Step S1: The remote control system calculates the sludge discharge of the biological treatment tank (3) based on the data fed back by the level gauge (20) and the sludge concentration meter (21). Step S2: The remote control system starts the delivery pump (11), and the biochemical tank (3) delivers the mud-water mixture to the relay sludge storage tank (1). When the mud-water mixture fed back by the third flow meter (22) reaches the preset value, the remote control system shuts down the delivery pump (11) and calculates the sludge concentration in the relay sludge storage tank (1). Step S3: The remote control system controls the amount of flocculant added to the flocculant preparation box (2) based on the conductivity data fed back by the conductivity meter (13) in the last two boxes of the flocculant preparation box (2) so as to achieve precise control of the flocculant concentration. Step S4: The remote control system controls the operation of the mud pump (9) and the chemical pump (18). The first flow meter (10) and the second flow meter (17) feed back the flow rate of the mud-water mixture and the chemical agent to the remote control system in real time, so as to realize that the mud-water mixture and the chemical agent are transported to the mixer (15) in a preset ratio and mixed evenly. In step S5, the mixture in the mixer (15) is transported to the centrifuge (4) for solid-liquid separation. The turbidity meter (16) monitors the turbidity of the supernatant discharged from the centrifuge (4) in real time and feeds the data back to the remote control system. The dewatered sludge separated in the centrifuge (4) is transported to the sludge bin by the screw conveyor (5).

7. The control method according to claim 6, characterized in that, The control of sludge discharge in steps S1 and S2 includes: Set the discharge sequence of the mud-water mixture in the biological treatment tank (3). The discharge sequence includes two parts: time period and planned discharge amount. The time period is the discharge interval, and the planned discharge amount refers to the amount of mud-water mixture discharged to the intermediate mud storage tank (1) in a single discharge. When the discharge is triggered, the discharge amount is controlled according to the following formula. Actual discharge = planned discharge + previous residue - current amount in intermediate sludge storage tank (1); where the current amount is calculated by measuring the remaining liquid level in intermediate sludge storage tank (1) using level gauge (20); Previous carryover = Previous planned emissions - Previous actual emissions; After the sludge discharge is completed, the remote control system calculates the actual sludge concentration of the sludge-water mixture in the relay sludge storage tank (1) according to formula (1): MLSS 实 =(V 排 *MLSS 排 +V 存 *MLSS 存 ) / (V 排 +V 存 ) formula(1) MLSS 实 -----The actual sludge concentration entering the mixer (15) is expressed in g / L; V 排 ------Amount of newly discharged sludge, in cubic meters (m³) 3 ; MLSS 排 ------Sludge concentration of newly discharged sludge, in g / L; V 存 -----The volume of sludge stored in the intermediate sludge storage tank (1), in m³ 3 ; MLSS 存 -----Sludge concentration of sludge retained in intermediate sludge storage tank (1), unit g / L; MLSS 存 =(V1*MLSS1+V2*MLSS2) / (V1+V2) Official (2) MLSS 存 -----Sludge concentration of sludge retained in intermediate sludge storage tank (1), unit g / L; V1-----The amount of sludge retained in the intermediate sludge storage tank (1), in m³ 3 ; V2-----Amount of newly discharged sludge into the intermediate sludge storage tank (1), in m³ 3 ; MLSS1----- The concentration of sludge retained in the intermediate sludge storage tank (1), in g / L; MLSS2------Concentration of newly discharged sludge into intermediate sludge storage tank (1), in g / L; The sludge concentration remaining in the intermediate sludge storage tank (1) after the Nth time is obtained by formula (2). If the intermediate sludge storage tank (1) is in continuous feeding and discharging condition, the average value of the sludge concentration meter (21) in the two most recent biochemical tanks (3) is taken as the actual sludge concentration value.

8. The control method according to claim 6, characterized in that, In step S3, the flocculant concentration control process includes: setting the conductivity curve and pH upper and lower limits of flocculant at 0.5‰ to 3.5‰, wherein the pH value of the second to last chamber is used for alarm, the conductivity of the second to last chamber is used to control the dosage, and the conductivity of the last chamber is used to control the frequency of the feed pump (18); in step S5, if the turbidity is higher or lower than the set value twice in a row, the remote control system issues an alarm; after 4 to 6 consecutive high value alarms, the centrifuge (4) automatically stops.

9. The control method according to claim 6, characterized in that, In step S4, the dosage of the agent is controlled according to formula (3): Q 药 =1000*MLSS 实 *Q 泥 *D*K / (c*ρ 药 ) Formula (3) K=A 标准 / A 实际 In the formula: A 标准 -----Theoretical conductivity of flocculant solution, in μs / cm; A 实际 ----- Actual conductivity measured after flocculant preparation, in μs / cm; K------Adjustment coefficient, used to characterize the effect of flocculant solution, dimensionless; Q 药 ------Flocculant dosage flow rate, in meters 3 / h; MLSS 实 ------ Actual sludge concentration entering the mixer (15), in g / L; Q 泥- ------The sludge inlet flow rate of the mixer (15), in m³ / s. 3 / h; D------Flocculant consumption, which is the amount of flocculant required per ton of absolutely dry sludge, in kg / t; c------Flocculant solution concentration; i.e., the ratio of the amount of flocculant dissolved to the weight of the flocculant solution, in per mille (‰); ρ 药 -----This refers to the mass of the flocculant per unit volume, expressed in kg / m³. 3 .

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