Method and device for judging concentration of suspended solids in mixed solution of sewage treatment system

Abstract

The invention relates to the technical field of sewage treatment, in particular to a method and device for judging the concentration of suspended solids in mixed liquor of a sewage treatment system. According to the specific technical scheme, the method for judging the concentration of the suspended solids in the mixed liquid of the sewage treatment system comprises the following steps: respectively measuring the highest OUR of the activated sludge system under different MLSS concentration conditions in a detection device, and carrying out linear fitting on the measured highest OUR and the corresponding MLSS to obtain a formula for calculating the MLSS of the activated sludge system, according to the method, the MLSS is rapidly calculated based on the linear relation between the highest OUR of the activated sludge and the MLSS.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a method and a device for judging the concentration of suspended solids in a mixed liquor of a sewage treatment system. Background Art

[0002] In the activated sludge sewage treatment system, the mixed liquor suspended solids concentration (MLSS) is an extremely critical control indicator. The mixed liquor suspended solids in the activated sludge system include microbial communities with metabolic functions, residues from endogenous respiration and self-oxidation of microorganisms, the concentration of inert organic matter that cannot be biodegraded adsorbed by the activated sludge, and inorganic matter attached to the activated sludge. In the operation of the activated sludge system, if the MLSS concentration is low, the concentration of active microorganisms is also low, and the removal capacity of various pollutants is insufficient; if the MLSS concentration is too high, on the one hand, due to the excessive active microorganisms, more oxygen will be consumed, and on the other hand, the aeration efficiency of the system will be reduced, affecting the system's effect on pollutant removal.

[0003] Sewage treatment systems are generally not equipped with MLSS online measuring instruments, especially some unattended sewage treatment systems located in remote areas. The conventional method for measuring MLSS in the laboratory is the weight method, in which it takes a long time to dry the filter paper and cannot obtain timely feedback on the results. Therefore, it is necessary to develop a method and device for quickly measuring the suspended solids concentration of the mixed liquor in the aerobic tank of the sewage treatment system. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method and device for determining the suspended solids concentration of a mixed liquor in a sewage treatment system. The method quickly calculates the MLSS of activated sludge based on the linear relationship between the maximum OUR and MLSS.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] The invention discloses a method for judging the suspended solid concentration of a mixed liquor in a sewage treatment system, the steps of which are: measuring the highest OUR under different MLSS concentration conditions of an activated sludge system in a detection device respectively, performing linear fitting on the measured highest OUR and the corresponding MLSS, and obtaining a formula for calculating the activated sludge MLSS.

[0007] Preferably, the maximum OUR of the activated sludge is the sum of the maximum OUR of heterotrophic bacteria and the maximum OUR of autotrophic bacteria.

[0008] Preferably, the highest OUR of the heterotrophic bacteria is: the DO decrease rate calculated after the DO decrease rate is stabilized after the carbon source is added to the activated sludge.

[0009] Preferably, the maximum OUR of the autotrophic bacteria is: the difference between the DO decrease rate calculated after the DO decrease rate stabilizes after ammonia nitrogen is added to the activated sludge, and the DO decrease rate calculated after the DO decrease rate stabilizes after the autotrophic bacteria inhibitor is added to the activated sludge.

[0010] Correspondingly, a device for determining the suspended solids concentration of a mixed liquor in a sewage treatment system comprises a detection device, wherein the detection device comprises a detection box with a top cover, a height-adjustable stirring mechanism is vertically arranged in the detection box, a cylindrical groove with an opening facing downward is vertically arranged at the bottom of the box wall of the detection box, a heating rod is arranged in the cylindrical groove; an annular groove is vertically arranged at the top of the box wall of the detection box, a cooling pipe row arranged in a serpentine shape is arranged in the annular groove, and the sum of the heights of the cylindrical groove and the annular groove is less than the height of the detection box; a reflux pipe is arranged on the top cover, a one-way valve is arranged on the reflux pipe, the other end of the reflux pipe extends into the bottom of the detection box, and the pipe mouth at the end is bent and arranged downward.

[0011] Preferably, an annular pressure strip is provided at the top of the detection box, a limiting strip extending into the annular groove is provided at the bottom of the pressure strip, and the width of the pressure strip is less than or equal to the thickness of the detection box; an annular fixing plate is provided at the bottom of the detection box, and the heating rod passes through the fixing plate and is fixed by a rubber sleeve.

[0012] Preferably, an annular aeration pipe is provided at the bottom of the detection box, an air inlet pipe is provided at the center of the aeration pipe, a plurality of connecting pipes are provided on the side wall of the air inlet pipe and communicated with the aeration pipe, and a plurality of air nozzles inclined downward are provided between the aeration pipe and the connecting pipe; the air inlet pipe extends out of the detection box and is connected to an air pump.

[0013] Preferably, a DO detector is connected to the side wall of the detection box through a detection tube, the outlet of the DO detector is connected to the detection box through a liquid outlet pipe, and a peristaltic pump is arranged on the detection tube; an exhaust pipe, a liquid filling hole and a pressure gauge are arranged on the top cover, and a telescopic hose is arranged on the reflux pipe near the top cover.

[0014] Preferably, the stirring mechanism includes a motor fixed on the top cover, the output shaft of the motor extends into the detection box, and is detachably connected to a connecting rod and / or a stirring shaft with blades; a plug is provided at one end of the connecting rod, a groove matching the plug is provided on the output shaft of the motor, an insertion pile is provided at the end of the stirring shaft, and an insertion groove matching the insertion pile is provided at the other end of the connecting rod, and the insertion pile is also matched with the groove.

[0015] Preferably, an OPR detector is arranged outside the detection box, and the detection probe of the OPR detector is located inside the detection box. A sliding rod is vertically arranged inside the detection box, a sliding block is sleeved on the sliding rod, a clamping ring is arranged on the sliding block, and the detection probe is clamped into the clamping ring and fixed; an adjusting screw corresponding to the position of the sliding rod is vertically arranged outside the detection box, a nut is arranged on the adjusting screw, and magnetic blocks are respectively arranged on the side walls corresponding to the nut and the sliding block.

[0016] The present invention has the following beneficial effects:

[0017] 1. The present invention measures the maximum OUR under different MLSS concentration conditions of the activated sludge system, performs linear fitting on the maximum OUR and MLSS, and the obtained linear equation is the formula for calculating MLSS; then the maximum OUR is measured in the daily operation of the sewage treatment system, and the MLSS is calculated according to the obtained linear equation, so that the MLSS concentration of the aerobic tank of the sewage treatment system can be quickly obtained, providing guidance for the control of its MLSS concentration and the discharge of excess sludge.

[0018] 2. The present invention can detect the DO, ammonia nitrogen, nitrite nitrogen and other conditions of the activated sludge in real time through the detection device. At the same time, through the reflux pipe, the gas overflowing from the activated sludge can be returned to the activated sludge to enhance aeration. The detection probe of the OPR detector that can move up and down is set in the detection box, which can detect the relevant data at different positions and flexibly adjust the detection position of the detection probe according to the liquid level depth. The detection device disclosed by the present invention is highly flexible during use and can be adjusted accordingly according to different operation processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the detection device of the present invention;

[0020] Figure 2 for Figure 1 AA view of the middle detection box;

[0021] Figure 3 for Figure 2 A partial enlarged view of;

[0022] Figure 4 Schematic diagram of aeration pipe structure;

[0023] Figure 5 is a schematic diagram of the connecting rod and the stirring shaft;

[0024] In the figure: top cover 1, detection box 2, heating rod 3, cooling pipe row 4, reflux pipe 5, one-way valve 6, pressure strip 7, fixing plate 8, aeration pipe 9, air inlet pipe 10, connecting pipe 11, air nozzle 12, DO detector 13, detection tube 14, liquid outlet pipe 15, peristaltic pump 16, exhaust pipe 17, pressure gauge 18, telescopic hose 19, motor 20, connecting rod 21, stirring shaft 22, plug 23, insertion pile 24, insertion groove 25, OPR detector 26, detection probe 27, sliding rod 28, slider 29, retaining ring 30, adjusting screw 31, nut 32, magnetic block 33, base 34, strip groove 35, discharge pipe 36. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0027] The present invention discloses a method for judging the concentration of suspended solids in a mixed liquor of a sewage treatment system, and the steps are as follows: the highest OUR (oxygen consumption rate) of an activated sludge system under different MLSS concentration conditions is measured in a detection device, and the measured highest OUR is linearly fitted with the corresponding MLSS to obtain a formula for calculating the MLSS of the activated sludge. The highest OUR of the activated sludge is the sum of the highest OUR of heterotrophic bacteria and the highest OUR of autotrophic bacteria. The highest OUR of the heterotrophic bacteria is: the DO decrease rate calculated after the DO decrease rate is stabilized after a carbon source is added to the activated sludge. The highest OUR of the autotrophic bacteria is: the difference between the DO decrease rate calculated after the DO decrease rate is stabilized after ammonia nitrogen is added to the activated sludge, and the DO decrease rate calculated after the DO decrease rate is stabilized after the autotrophic bacteria inhibitor is added to the activated sludge.

[0028] Specifically: The purpose of the present invention is to quickly determine the concentration of suspended solids in the mixed liquor of the aerobic pool of the sewage treatment system. The specific process is:

[0029] (1) Take the activated sludge mixed liquor in the aerobic tank of the sewage treatment system in stable operation, measure its suspended solid concentration (MLSS) according to the gravimetric method (CJ 221-2005), and then dilute or concentrate it into activated sludge mixed liquors with different MLSS concentrations according to different proportions.

[0030] (2) The highest OUR of the activated sludge with different MLSS concentrations was determined respectively. The determination steps were as follows:

[0031] ⅰ) Take a certain volume of activated sludge mixed liquor and put it in the detection device, adjust it to a certain temperature, keep stirring, add sodium chlorate solution and ATU (allylthiourea) solution to make their concentrations in the activated sludge mixed liquor 2.13g / L and 5mg / L respectively, so as to inhibit the activity of autotrophic bacteria, aerate until it is close to saturation, stop aeration, and record DO regularly (recording time 1 to 3min) after the DO decrease rate stabilizes, and calculate the DO decrease rate, which is recorded as R1.

[0032] ii) Aerate until it is close to saturation, add sodium acetate solution to make the COD of the mixed solution after addition to about 200 mg / L, stop aeration, and record DO regularly (recording time 1 to 3 minutes) after the DO decrease rate stabilizes, and calculate the DO decrease rate, which is recorded as R2.

[0033] ⅲ) Take another activated sludge mixed solution from step i), adjust it to the same temperature, keep stirring, aerate until it is close to saturation, add a mixed solution of ammonium chloride and sodium nitrite, so that the NH4-N concentration and NO2-N concentration of the mixed solution after addition are both about 5 mg / L, stop aeration, and record DO regularly (recording time 1 to 3 minutes) after the DO decrease rate stabilizes, and calculate the DO decrease rate, which is recorded as R3.

[0034] The calculation method of the maximum OUR is as follows: the maximum OUR of heterotrophic bacteria: OUR(max;HET)=R2, the maximum OUR of autotrophic bacteria: OUR(max;A)=R3-R1, the total maximum OUR: OUR(max)=OUR(max;HET)+OUR(max;A).

[0035] (3) Perform a linear fit between the highest OUR measured and the corresponding MLSS. The linear equation obtained by the fit is the formula for quickly calculating the MLSS of activated sludge.

[0036] In the daily operation of the sewage treatment system, the maximum OUR is quickly determined according to the above method, and then the MLSS is calculated according to the obtained linear equation. If the system operation mode, season, etc. change, the linear relationship between the maximum OUR and MLSS needs to be recalibrated.

[0037] The present invention calculates MLSS based on the linear relationship between the maximum OUR of activated sludge and MLSS. According to the activated sludge model ASM1 proposed by the International Association for Water Quality (IAWQ), the consumption rate of dissolved oxygen for aerobic growth of heterotrophic bacteria and autotrophic bacteria in the activated sludge system, i.e., the OUR of heterotrophic bacteria and autotrophic bacteria, are:

[0038]

[0039] Where Y H , YA -The yield coefficients of heterotrophic bacteria and autotrophic bacteria, mg microorganisms / mg substrate, are generally 0.67 and 0.24 respectively; μ H , μ A - Maximum specific growth rate of heterotrophic and autotrophic bacteria, d -1 ; S S - Biodegradable organic matter concentration, mgCOD / L; K S - half-saturation constant of biodegradable organic matter, mgCOD / L, generally 20 mgCOD / L; S NH - Ammonia nitrogen concentration, mgN / L; K NH - ammonia nitrogen half-saturation constant, mgN / L, generally 1mgN / L; S O -Dissolved oxygen concentration, mg / L; K O,H , K O,A - Dissolved oxygen half-saturation concentration, mg / L, generally 0.2mg / L and 0.4mg / L respectively; X H , X A -Concentration of active heterotrophic and autotrophic bacteria, mgCOD / L.

[0040] According to the above formula, i) if the temperature remains stable, the maximum specific growth rate in the formula remains basically unchanged; ii) if the easily degradable organic matter and ammonia nitrogen are sufficient, the factor Close to 1. Because when measuring OUR, the activated sludge mixed liquor is aerated to near saturation, It is also close to 1. Therefore, the highest OUR of heterotrophic bacteria and autotrophic bacteria is a linear function of their concentration. Since the composition of activated sludge in a stable system remains basically unchanged, the proportion of active microorganisms in suspended solids can also be considered to remain basically unchanged, and MLSS can be calculated based on the highest OUR.

[0041] The present invention will be further described below in conjunction with specific embodiments.

[0042] Example

[0043] The rapid determination process of the suspended solids concentration of the mixed liquor in the activated sludge system is as follows:

[0044] (1) For an aerobic pool of an integrated sewage treatment equipment built by an environmental protection company and an MBR pool of a sewage treatment plant, the present invention is used to calculate MLSS based on the linear relationship between the highest OUR and MLSS.

[0045] (2) The detection device developed by the Chengdu Institute of Biology, Chinese Academy of Sciences was used to determine the OUR of activated sludge.

[0046] (3) The activated sludge mixed liquor in the aerobic tank of an integrated sewage treatment equipment with stable operation and the MBR tank of a sewage treatment plant was taken, and its suspended solid concentration (MLSS) was determined according to the gravimetric method (CJ 221-2005). Then, it was diluted or concentrated into activated sludge mixed liquors with different MLSS concentrations according to different proportions.

[0047] (4) The highest OUR under different MLSS concentration conditions of the above-mentioned activated sludge is measured using the detection device disclosed in the present invention, and the measurement steps are as follows:

[0048] ⅰ) Take a certain volume of activated sludge mixed liquor and put it in the detection device, adjust it to a certain temperature, keep stirring, add sodium chlorate solution and ATU solution to make their concentrations in the activated sludge mixed liquor 2.13g / L and 5mg / L respectively, so as to inhibit the activity of autotrophic bacteria, aerate until it is close to saturation, stop aeration, and record DO regularly (recording time 1 to 3min) after the DO decrease rate stabilizes, and calculate the DO decrease rate, which is recorded as R1.

[0049] ii) Aerate until it is close to saturation, add sodium acetate solution to make the COD of the mixed solution after addition to about 200 mg / L, stop aeration, and record DO regularly (recording time 1 to 3 minutes) after the DO decrease rate stabilizes, and calculate the DO decrease rate, which is recorded as R2.

[0050] ⅲ) Take another activated sludge mixed solution from step i), adjust it to the same temperature, keep stirring, aerate until it is close to saturation, add a mixed solution of ammonium chloride and sodium nitrite, so that the NH4-N concentration and NO2-N concentration of the mixed solution after addition are both about 5 mg / L, stop aeration, and record DO regularly (recording time 1 to 3 minutes) after the DO decrease rate stabilizes, and calculate the DO decrease rate, which is recorded as R3.

[0051] The maximum OUR is calculated as follows: OUR(max; HET) = R2, OUR(max; A) = R3-R1, OUR(max) = OUR(max; HET) + OUR(max; A).

[0052] (5) The measured maximum OUR of the activated sludge in the aerobic tank of the integrated sewage treatment equipment and the MBR tank of a sewage treatment plant were linearly fitted with the corresponding MLSS. The linear equation obtained by the fitting is the formula for quickly calculating the MLSS of the activated sludge. If the operation mode, season, etc. of the system change, the linear relationship between the maximum OUR and MLSS needs to be recalibrated. The fitting data of the maximum OUR and the corresponding MLSS are shown in Table 1.

[0053] (6) The maximum OUR of activated sludge measured in the aerobic tank during the operation of the integrated sewage treatment equipment, the MLSS calculated based on the maximum OUR, the MLSS measured by the weight method, the relative error, and the linear formula between the maximum OUR and MLSS are summarized in Table 2. The maximum OUR of activated sludge measured in the MBR tank of a sewage treatment plant, the MLSS calculated based on the maximum OUR, the MLSS measured by the weight method, the relative error, and the linear formula between the maximum OUR and MLSS are summarized in Table 3.

[0054] Table 1 Summary of fitting data of the highest OUR and corresponding MLSS

[0055]

[0056] Table 2 Summary of MLSS data of aerobic pool of integrated sewage treatment equipment calculated based on the highest OUR

[0057]

[0058]

[0059] Table 3 Calculation of MLSS data of MBR pool in a sewage treatment plant based on the highest OUR

[0060]

[0061]

[0062] The results show that: From Table 1, it can be seen that the MLSS of the aerobic pool of the integrated sewage treatment equipment and the MBR pool of a sewage treatment plant have a good linear relationship with the maximum OUR of the activated sludge. From Table 2, it can be seen that the average value of the MLSS calculated value of the aerobic pool of the integrated sewage treatment equipment is 2478.6 mg / L, the average value of the MLSS measured value is 2439.5 mg / L, and the average relative error is 8.05%. From Table 3, it can be seen that the average value of the MLSS calculated value of the MBR pool of a sewage treatment plant is 19028.7 mg / L, the average value of the MLSS measured value is 20144.4 mg / L, and the average relative error is 8.73%. Therefore, in the activated sludge system, the calculation of MLSS based on the linear relationship between OUR(max) and MLSS has considerable accuracy.

[0063] refer to Figure 1-Figure 5The present invention also discloses a device for measuring the suspended solids concentration of the mixed liquor of an activated sludge system, namely, the aerobic tank of the integrated sewage treatment equipment mentioned in the above embodiment, including a detection device, wherein the detection device includes a detection box 2 with a top cover 1, the top cover is hinged to the detection box and can be sealed and fixed by a buckle, a drain pipe 36 is arranged at the bottom of the detection box, and a valve is arranged on the drain pipe, and the activated sludge can be discharged after the reaction is completed. The detection box 2 is vertically provided with a height-adjustable stirring mechanism, and the bottom of the box wall of the detection box 2 is vertically provided with a cylindrical groove with an opening facing downward, and a heating rod 3 is provided in the cylindrical groove. Heating is achieved by energizing the heating rod. At the same time, the number of energized heating rods can be selected as needed to avoid excessive temperature in the detection box; the top of the box wall of the detection box 2 is vertically provided with an annular groove, which is arranged around the detection box, and a cooling pipe row 4 arranged in a serpentine shape is arranged in the annular groove. The cooling pipe row is also arranged around the detection box, and the inlet end and the outlet end of the cooling pipe row are adjacent or close, extending out of the detection box through the side wall of the detection box and connected to the cooling box. When cooling is required, cooling water or coolant is transported into the cooling pipe row through a pump, and discharged into the cooling box through the outlet end to form a cycle. The cooling box has a refrigeration function, which is a prior art. In order to avoid condensation of water droplets in the annular groove, an outlet that penetrates the detection box is provided on the side wall at the bottom of the annular groove, and condensed water can be discharged through a connecting pipe (not shown in the figure).

[0064] Furthermore, the height of the cylindrical groove and the annular groove is less than the height of the detection box 2, so that there is a certain distance between the cylindrical groove and the annular groove; a reflux pipe 5 is provided on the top cover 1, and a one-way valve 6 is provided on the reflux pipe 5. The other end of the reflux pipe 5 extends into the bottom of the detection box 2, and the pipe mouth at the end is bent downward. It should be noted that the setting of the reflux pipe can allow the gas in the aeration process to enter the detection box again through the reflux pipe to enhance the aeration effect. At the same time, a one-way valve is provided to allow the gas to move from top to bottom. The end of the reflux pipe located in the detection box is bent downward to prevent activated sludge and the like from entering the reflux pipe and blocking the reflux pipe.

[0065] Furthermore, in order to prevent the cooling tube row from being exposed, the top of the detection box 2 is provided with an annular pressure strip 7, and the bottom of the pressure strip 7 is provided with a limit strip extending into the annular groove, so that the annular groove forms a relatively closed space, and the width of the pressure strip 7 is less than or equal to the thickness of the detection box 2. At the same time, the pressure strip and the limit strip can be made of rubber material, and the detection box can be sealed with the top cover; the bottom of the detection box 2 is provided with an annular fixing plate 8, and the heating rod 3 passes through the fixing plate 8 and is fixed by a rubber sleeve, that is, the heating rod is fixed on the fixing plate. Furthermore, a rubber sleeve is provided through the fixing plate, and the heating rod is fixed through the rubber sleeve to achieve the purpose of heat insulation, and the terminal of the heating rod is exposed outside the fixing plate. Of course, the heating speed can be controlled by selecting the number of heating rods installed on the fixing plate. At the same time, combined with the cooling tube row, the heating and cooling of the detection box are realized.

[0066] Furthermore, the bottom of the detection box 2 is provided with an annular aeration pipe 9. In order to make the aeration more uniform, the aeration pipe is arranged along the inner bottom edge of the detection box. An air inlet pipe 10 is arranged at the center of the aeration pipe 9. The air inlet pipe runs through the bottom of the detection box. A plurality of connecting pipes 11 are arranged on the side wall of the air inlet pipe 10 to communicate with the aeration pipe 9. A plurality of air nozzles 12 inclined downward are arranged between the aeration pipe 9 and the connecting pipe 11. The inclination angle is less than or equal to 30°, which prevents the activated sludge from entering the air nozzle to a certain extent. The air inlet pipe 10 extends out of the detection box 2 and is connected to an air pump. The air pump can be connected to a gas cylinder or directly communicated with the outside world, depending on the type of aerated gas, such as oxygen or air. By filling the air inlet pipe with gas and spraying it out through the connecting pipe and the air nozzle on the aeration pipe, uniform aeration is achieved, and uneven aeration caused by concentrated aeration is avoided.

[0067] Furthermore, a DO detector 13 is connected to the side wall of the detection box 2 through a detection tube 14. One end of the detection tube that extends into the detection box can be connected to a telescopic tube, so that different detection depths can be selected according to actual conditions. Of course, the setting of the telescopic tube is determined according to the depth of the activated sludge in the detection box and is installed in advance. The outlet of the DO detector 13 is connected to the detection box 2 through a liquid outlet pipe 15. A peristaltic pump 16 is provided on the detection tube 14. The liquid is pumped into the DO detector for detection through the peristaltic pump. After the detection is completed, the liquid is transported to the detection box. At the same time, in order to avoid clogging of the outlet pipe, the end of the liquid outlet pipe that extends into the detection box is also bent downward.

[0068] Furthermore, the top cover 1 is provided with an exhaust pipe 17, a liquid filling hole and a pressure gauge 18, and the reflux pipe 5 is provided with a telescopic hose 19 near the top cover 1. It should be noted that: a collection bottle can be connected to the other end of the exhaust pipe to collect the excess gas after aeration and saturation. At the same time, in combination with the pressure gauge, by monitoring the pressure in the detection box, the valve on the exhaust pipe can be opened to exhaust and collect. The valve can be a solenoid valve, and the value change of the pressure gauge and the opening of the valve can be monitored by the controller. A section of the telescopic hose is set on the reflux pipe, and the setting position is close to the hinge between the top cover and the detection box. When the top cover is opened, the reflux pipe does not affect its opening and closing.

[0069] Further, the stirring mechanism includes a motor 20 fixed on the top cover 1, the output shaft of the motor 20 extends into the detection box 2, and is detachably connected with a connecting rod 21 and / or a stirring shaft 22 with blades; the setting of the connecting rod is intended to lengthen the length of the entire stirring shaft, and adjust the stirring position according to the liquid level in the detection box. Therefore, at least one connecting rod can be set, or it can be set without setting, and the output shaft of the motor is directly fixed to the stirring shaft. Specifically: a plug 23 is set at one end of the connecting rod 21, a groove adapted to the plug 23 is set on the output shaft of the motor 20, an insertion pile 24 is set at the end of the stirring shaft 22, and an insertion groove 25 adapted to the insertion pile 24 is set at the other end of the connecting rod 21, and the insertion pile 24 is also adapted to the groove. At the same time, through holes are set through the plug, the insertion pile, the insertion groove and the groove. When the connecting rod, the output shaft and the stirring shaft are all inserted and connected, and the through holes of each part are made to correspond, bolts are passed through the through holes to fix them in pairs.

[0070] Furthermore, an OPR detector 26 is arranged outside the detection box 2. A plurality of OPR detectors 26 can be arranged as needed. The detection probe 27 of the OPR detector 26 is located inside the detection box 2, that is, the wires of the OPR detector and the detection probe pass through the detection box and are fixed by a sealing rubber, that is, the sealing rubber runs through the detection box, and the wires pass through the sealing rubber. A sliding rod 28 is vertically arranged inside the detection box 2, a slider 29 is sleeved on the sliding rod 28, a clamping ring 30 is arranged on the slider 29, and the detection probe 27 is clamped into the clamping ring 30 and fixed. The clamping ring is two arc-shaped blocks with a certain deformation ability, and the detection probe is fixed in the clamping ring; an adjusting screw 31 corresponding to the position of the sliding rod 28 is vertically arranged outside the detection box 2, a nut 32 is arranged on the adjusting screw 31, and magnetic blocks 33 are respectively arranged on the side walls corresponding to the nut 32 and the slider 29. It should be noted that the slide rod is a smooth rod, and the two ends of the slide rod and the adjusting screw rod are fixed by the base 34 respectively. The slider moves the detection probe up and down along the slide rod, so as to detect the activated sludge at different positions. At the same time, the position of the detection probe is adjusted according to the liquid level in the detection box. The adjusting screw rod and nut can be selected as a screw rod and a nut, which can be driven to rotate by a motor. Magnetic blocks are set on the nut and the slider, so that the detection probe can be driven to move up and down outside the detection box.

[0071] Furthermore, in order to prevent the wall thickness of the detection box from affecting the suction force of the magnetic block, a strip groove 35 is vertically arranged outside the detection box, and the adjusting screw is arranged in the strip groove to reduce the thickness between the two magnetic blocks, thereby increasing their suction force and preventing the detection probe from falling into the detection box.

[0072] Furthermore, in order to enable the detection probe to move up and down, the wires on the detection probe are arranged in a spiral shape, which does not affect the up and down movement of the detection probe and also stores the wires to a certain extent.

[0073] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0074] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for determining the suspended solids concentration of a mixed liquor in a sewage treatment system, characterized in that: The steps are: measuring the highest OUR under different MLSS concentration conditions of the activated sludge system in the detection device respectively, performing linear fitting between the measured highest OUR and the corresponding MLSS, and obtaining the formula for calculating the activated sludge MLSS.

2. A method for determining the suspended solids concentration of a mixed liquor in a sewage treatment system according to claim 1, characterized in that: The highest OUR of the activated sludge is the sum of the highest OUR of heterotrophic bacteria and the highest OUR of autotrophic bacteria.

3. A method for determining the suspended solids concentration of a mixed liquor in a sewage treatment system according to claim 2, characterized in that: The highest OUR of the heterotrophic bacteria is: after the carbon source is added to the activated sludge, the DO decrease rate is calculated after the DO decrease rate stabilizes.

4. A method for determining the concentration of suspended solids in a mixed liquor of a sewage treatment system according to claim 2, characterized in that: The highest OUR of the autotrophic bacteria is: the difference between the DO decrease rate calculated after the DO decrease rate stabilizes after ammonia nitrogen is added to the activated sludge and the DO decrease rate calculated after the DO decrease rate stabilizes after the autotrophic bacteria inhibitor is added to the activated sludge.

5. A device for measuring the suspended solids concentration of a mixed liquor in a sewage treatment system according to any one of claims 1 to 4, characterized in that: The invention comprises a detection device, wherein the detection device comprises a detection box (2) with a top cover (1), a height-adjustable stirring mechanism is vertically arranged in the detection box (2), a cylindrical groove with an opening facing downward is vertically arranged at the bottom of the box wall of the detection box (2), and a heating rod (3) is arranged in the cylindrical groove; an annular groove is vertically arranged at the top of the box wall of the detection box (2), and a cooling pipe row (4) arranged in a serpentine shape is arranged in the annular groove, and the sum of the heights of the cylindrical groove and the annular groove is less than the height of the detection box (2); a reflux pipe (5) is arranged on the top cover (1), and a one-way valve (6) is arranged on the reflux pipe (5), and the other end of the reflux pipe (5) extends into the bottom of the detection box (2), and the pipe mouth at the end is bent and arranged to face downward.

6. A device for determining the concentration of suspended solids in a mixed liquor of a sewage treatment system according to claim 5, characterized in that: The top of the detection box (2) is provided with an annular pressure strip (7), the bottom of the pressure strip (7) is provided with a limit strip extending into the annular groove, and the width of the pressure strip (7) is less than or equal to the thickness of the detection box (2); the bottom of the detection box (2) is provided with an annular fixing plate (8), and the heating rod (3) passes through the fixing plate (8) and is fixed by a rubber sleeve.

7. A device for determining the concentration of suspended solids in a mixed liquor of a sewage treatment system according to claim 5, characterized in that: An annular aeration pipe (9) is arranged at the bottom of the detection box (2); an air inlet pipe (10) is arranged at the center of the aeration pipe (9); a plurality of connecting pipes (11) are arranged on the side wall of the air inlet pipe (10) and communicate with the aeration pipe (9); a plurality of air nozzles (12) are arranged between the aeration pipe (9) and the connecting pipes (11) and are inclined downward; the air inlet pipe (10) extends out of the detection box (2) and is connected to an air pump.

8. The device for determining the concentration of suspended solids in a mixed liquor of a sewage treatment system according to claim 5, characterized in that: A DO detector (13) is connected to the side wall of the detection box (2) via a detection tube (14); the outlet of the DO detector (13) is connected to the detection box (2) via a liquid outlet tube (15); a peristaltic pump (16) is arranged on the detection tube (14); an exhaust pipe (17), a liquid filling hole and a pressure gauge (18) are arranged on the top cover (1); and a telescopic hose (19) is arranged on the reflux pipe (5) near the top cover (1).

9. A device for determining the concentration of suspended solids in a mixed liquor of a sewage treatment system according to claim 5, characterized in that: The stirring mechanism comprises a motor (20) fixed on the top cover (1); the output shaft of the motor (20) extends into the detection box (2) and is detachably connected to a connecting rod (21) and / or a stirring shaft (22) with blades; a plug (23) is provided at one end of the connecting rod (21); a groove matched with the plug (23) is provided on the output shaft of the motor (20); an insertion pile (24) is provided at the end of the stirring shaft (22); an insertion groove (25) matched with the insertion pile (24) is provided at the other end of the connecting rod (21); the insertion pile (24) is also matched with the groove.

10. The device for determining the concentration of suspended solids in mixed liquor of a sewage treatment system according to claim 5, characterized in that: An OPR detector (26) is arranged outside the detection box (2), and a detection probe (27) of the OPR detector (26) is located inside the detection box (2). A sliding rod (28) is vertically arranged inside the detection box (2), a slider (29) is sleeved on the sliding rod (28), a clamping ring (30) is arranged on the slider (29), and the detection probe (27) is clamped into the clamping ring (30) for fixation; an adjusting screw (31) corresponding to the position of the sliding rod (28) is vertically arranged outside the detection box (2), a nut (32) is arranged on the adjusting screw (31), and magnetic blocks (33) are respectively arranged on the side walls corresponding to the nut (32) and the slider (29).

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