A method and system for evaluating biological phosphorus removal efficiency in sewage treatment plants

Abstract

The present invention belongs to the field of sewage treatment technology and discloses a method and system for evaluating the biological phosphorus removal efficiency of a sewage treatment plant. The system includes a sewage detection unit, a sludge detection unit, and a data analysis and calculation unit; the sewage detection unit includes a sewage storage device, a filtration device, a filtrate storage device, and an online phosphate measurement device connected in sequence; the sludge detection unit includes an activated sludge storage device, a solid-liquid separation device, a sludge elutriation device, a sludge thermal drying device, a sludge incineration device, an MLVSS measurement device, a sludge freeze-drying device, a sludge high-temperature oxidation leaching device, and a polyphosphate measurement device. The method and system of the present invention can accurately determine the proportion of biological phosphorus removal, guiding the operation and regulation of water plants.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and more specifically, relates to a method and system for evaluating the biological phosphorus removal efficiency of a sewage treatment plant. Background Art

[0002] To further improve water quality, total phosphorus (TP) discharge standards for urban sewage treatment plants in key river basins and regions have been further tightened. These increasingly stringent TP discharge standards place higher demands on the phosphorus removal efficiency of urban sewage treatment plants.

[0003] Compared with chemical phosphorus removal, biological phosphorus removal does not require the addition of additional chemical agents, saving a lot of agent costs. In addition, the sludge produced by the biological phosphorus removal process is easy to dewater, and the sludge has a high nutrient content, which is of great value for the subsequent sludge reuse. However, due to factors such as the influent carbon source, anaerobic environment and nitrate nitrogen, the biological phosphorus removal effect of the sewage treatment plant is difficult to control. Therefore, in order to ensure that the effluent phosphorus content is stable and meets the standards, an appropriate amount of chemical agents will be added, and a biological + chemical method will be used to remove phosphorus from the sewage. Although the addition of chemical phosphorus removal agents will promote the phosphorus removal effect, it is difficult to control the dosage of the agent, and it is basically in an excessive state. This causes some unreacted phosphorus removal agents and hydrolysis products to flow back into the front-end biological treatment system with the sludge, so that the activated sludge also has the ability to remove phosphorus physically and chemically. This situation will interfere with the operator's judgment on the biological phosphorus removal capacity of the system.

[0004] At present, the characterization of biological phosphorus removal capacity in sewage treatment plants is mostly focused on anaerobic phosphorus release and aerobic phosphorus uptake. However, this analysis method is based on the premise that there are no chemical phosphorus removal agents. For the biochemical synergistic phosphorus removal method, this characterization method has a large error, because the residual phosphorus removal agents in the sludge still play a phosphorus removal role in the entire biological treatment process, which couples the biological phosphorus removal effect and the chemical phosphorus removal effect together, and it is impossible to accurately distinguish their respective capabilities and proportions. As a result, the operating personnel are unable to accurately adjust the addition of chemical phosphorus removal agents according to the biological phosphorus uptake, which leads to excessive agents and further increased costs.

[0005] Currently, the more common analytical method is to evaluate the strength of biological phosphorus removal ability through changes in polyphosphate-accumulating bacteria. However, this method is complex to operate, has very high requirements for the testing environment, requires professional personnel to operate, and is time-consuming. In addition, the test results can only indicate whether the system has the ability to remove phosphorus biologically, but cannot characterize the proportion of biological phosphorus removal. It can only be qualitative, not quantitative.

[0006] Therefore, it is urgent to propose a method and system for evaluating the biological phosphorus removal efficiency of sewage treatment plants. Summary of the Invention

[0007] The present invention aims to address the problem of inaccurately assessing the effectiveness of biological phosphorus removal in sewage treatment plants by providing a method and system for evaluating the effectiveness of biological phosphorus removal in sewage treatment plants. The method and system of the present invention can accurately determine the contribution of biological phosphorus removal to guide water plant operation and regulation.

[0008] In order to achieve the above object, the present invention provides a system for evaluating the biological phosphorus removal efficiency of a sewage treatment plant, the system comprising a sewage detection unit, a sludge detection unit and a data analysis and calculation unit;

[0009] The sewage detection unit includes a sewage storage device, a filtering device, a filtrate storage device and a phosphate online measuring device connected in sequence; the phosphate online measuring device is used to measure the orthophosphate concentration of the total influent of the sewage treatment plant and transmit the data to the data analysis and calculation unit;

[0010] The sludge detection unit includes an activated sludge storage device, a solid-liquid separation device, a sludge elutriation device, a sludge thermal drying device, a sludge incineration device, an MLVSS measuring device, a sludge freeze drying device, a sludge high-temperature oxidation leaching device and a polyphosphate measuring device;

[0011] The activated sludge storage device, the solid-liquid separation device and the sludge elutriation device are connected in sequence; the outlet of the sludge elutriation device is divided into two routes, one route is connected in sequence to the sludge thermal drying device, the sludge incineration device and the MLVSS measuring device, and the other route is connected in sequence to the sludge freeze drying device, the sludge high-temperature oxidation leaching device and the polyphosphate measuring device;

[0012] The MLVSS measuring device is used to measure the MLVSS concentration of activated sludge and transmit the data to the data analysis and calculation unit; the polyphosphate measuring device is used to measure the polyphosphate content in activated sludge and transmit the data to the data analysis and calculation unit.

[0013] In the present invention, the data analysis and calculation unit is a computer system well known to those skilled in the art.

[0014] According to the present invention, preferably, the volumes of the sewage storage device, the filtrate storage device and the activated sludge storage device are independently 5-10L.

[0015] According to the present invention, preferably, the sewage storage device is provided with a sample outlet in the middle and a first drain outlet in the lower portion; the sample outlet and the filtering device are connected in sequence via a valve and a peristaltic pump.

[0016] In the present invention, the filter element of the filtering device has a pore size of 0.4-0.5 μm, which is used to filter particulate matter in sewage to prevent suspended matter from interfering with the detection results of orthophosphate.

[0017] According to the present invention, preferably, the filtrate storage device is provided with a first sampling port at the top and a second drain port at the bottom.

[0018] According to the present invention, preferably, the phosphate online measuring device includes a power supply, a display screen, a water inlet, a water outlet, a sampling pump, a phosphate detection reagent, a first photometer and a first signal transmission and communication module; the water inlet is connected to the first sampling port through the sampling pump; the first photometer is used to detect the photometric value after the sewage entering the phosphate online measuring device reacts with the phosphate detection reagent; the first signal transmission and communication module is used to transmit the orthophosphate concentration data of the total influent of the sewage treatment plant to the data analysis and calculation unit.

[0019] In the present invention, the photometric value detected by the first photometer is the orthophosphate concentration of the total influent of the sewage treatment plant. As a preferred embodiment, the first photometer is a DR6000 spectrophotometer.

[0020] In the present invention, the drain port of the sewage storage device, the drain port of the filtrate storage device and the water outlet of the phosphate online determination device are all used to drain the remaining water samples in their respective devices.

[0021] According to the present invention, preferably, a second sampling port is provided at the bottom of the sludge storage device to take the sludge settled at the bottom for detection.

[0022] According to the present invention, preferably, the solid-liquid separation device includes a high-speed centrifuge.

[0023] According to the present invention, preferably, the sludge washing device includes a constant temperature oscillator and a high-speed centrifuge.

[0024] According to the present invention, preferably, the sludge thermal drying device includes an electric heating blast drying box.

[0025] According to the present invention, preferably, the sludge incineration device includes a high-temperature muffle furnace.

[0026] According to the present invention, preferably, the MLVSS measuring device includes a second signal transmission communication module for transmitting the activated sludge MLVSS concentration data to the data analysis and calculation unit.

[0027] According to the present invention, preferably, the sludge freeze-drying device includes a freeze dryer.

[0028] According to the present invention, preferably, the sludge high-temperature oxidation leaching device includes a high-pressure steam sterilizer.

[0029] According to the present invention, preferably, the polyphosphate measuring device includes a second photometer and a third signal transmission and communication module, wherein the third signal transmission and communication module is used to transmit data on the polyphosphate content in the activated sludge to the data analysis and calculation unit. As a preferred embodiment, the second photometer is a DR6000 spectrophotometer.

[0030] Another aspect of the present invention provides a method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant. The method uses the system for evaluating the biological phosphorus removal efficiency of a sewage treatment plant, and comprises the following steps:

[0031] S1: The total influent of the sewage treatment plant is sent to the sewage storage device, and after being filtered, it enters the filtrate storage device, and the orthophosphate concentration of the total influent of the sewage treatment plant is measured by the phosphate online measuring device, and the data is transmitted to the data analysis and calculation unit;

[0032] S2: The activated sludge at the end of the aerobic tank is sent to the activated sludge storage device, and after the supernatant is removed by the first round of centrifugation, the bottom sludge is sent to the sludge elutriation device; in the sludge elutriation device, the bottom sludge is mixed with water to obtain a mud-water mixture, which is then shaken and centrifuged in the second round to obtain centrifugally elutriated sludge;

[0033] Part of the centrifugally elutriated sludge is sequentially subjected to heat drying and incineration, and then the MLVSS concentration of the activated sludge at the end of the aerobic tank is measured by the MLVSS measuring device, and the data is transmitted to the data analysis and calculation unit; the remaining part is sequentially subjected to vacuum freeze drying and high-temperature oxidation leaching, and then the polyphosphate content in the activated sludge at the end of the aerobic tank is measured by the polyphosphate measuring device, and the data is transmitted to the data analysis and calculation unit;

[0034] S3: Repeat the operation of step S2 for the activated sludge at the end of the anaerobic tank to obtain the MLVSS concentration data of the activated sludge at the end of the anaerobic tank and the polyphosphate content data in the activated sludge at the end of the anaerobic tank;

[0035] S4: A calculation formula is preset in the data analysis and calculation unit, and the proportion of biological phosphorus removal in the sewage treatment plant is calculated using the orthophosphate concentration data of the total influent of the sewage treatment plant, the MLVSS concentration data of the activated sludge at the end of the aerobic tank, the polyphosphate content data in the activated sludge at the end of the aerobic tank, and the polyphosphate content data in the activated sludge at the end of the anaerobic tank. Steps S1-S4 are repeated multiple times to take the average value.

[0036] According to the present invention, preferably, in step S1,

[0037] The total influent water of the sewage treatment plant in the sewage storage device is sent to the filtering device through a valve and a peristaltic pump for filtration; the flow rate of the peristaltic pump is 400-600 mL / min, and the set time is 8-12 minutes;

[0038] The method for measuring the orthophosphate concentration of the total influent of a sewage treatment plant by the phosphate online measuring device comprises: using the first photometer to measure the photometric value of the sewage entering the phosphate online measuring device after reacting with the phosphate detection reagent and transmitting the data to the data analysis and calculation unit;

[0039] In the present invention, as a preferred embodiment, the phosphate detection reagent is Hach's phosphate rapid detection reagent.

[0040] According to the present invention, preferably, in step S2,

[0041] The first round of centrifugation has a rotation speed of 5000-6500 r / min and a time of 15-25 min;

[0042] The volume of the activated sludge at the end of the aerobic tank undergoing the first round of centrifugation is the same as the volume of the mud-water mixture, that is, in the present invention, the bottom sludge is mixed with water to restore the sludge volume to the volume of the activated sludge at the end of the aerobic tank undergoing the first round of centrifugation.

[0043] Repeat the shaking and the second round of centrifugation 2-5 times to wash away the residual dissolved phosphorus in the sludge;

[0044] The ratio of the heat-dried centrifugal elutriated sludge to the freeze-dried centrifugal elutriated sludge is 1:(0.95-1.05);

[0045] The heat drying temperature is 90-120°C and the time is 1.5-2.5h;

[0046] The incineration temperature is 550-650°C and the time is 0.5-1.5h;

[0047] The vacuum freeze drying temperature is -35 to -45°C, the vacuum degree is 0.10-0.15 mbar, and the time is 20-40 hours;

[0048] The high-temperature oxidation leaching method comprises: mixing the vacuum freeze-dried sludge with water and a potassium persulfate aqueous solution, placing the mixture in a high-pressure steam sterilizer, and oxidizing and leaching the mixture at 100-150° C. for 25-35 minutes;

[0049] The method for measuring the polyphosphate content in the activated sludge at the end of the aerobic tank by the polyphosphate measuring device includes: mixing the sludge leached by the high-temperature oxidation with ascorbic acid and ammonium molybdate for color development, and using the second photometer to measure the polyphosphate content in the activated sludge at the end of the aerobic tank and transmitting the data to the data analysis and calculation unit.

[0050] According to the present invention, preferably, the usage ratio of the vacuum freeze-dried sludge, water and potassium persulfate aqueous solution is 9: (18-22): (6-10) mg / mL / mL.

[0051] According to the present invention, preferably, the volume ratio of the high temperature oxidation leaching sludge, ascorbic acid and ammonium molybdate is 50: (0.5-1.5): (1.5-2.5).

[0052] According to the present invention, preferably, in step S4, the calculation formula includes:

[0053] Dissolved phosphorus removed by biological phosphorus removal (mg / L) = (polyphosphate content in activated sludge at the end of the aerobic tank (mg / g) - polyphosphate content in activated sludge at the end of the anaerobic tank (mg / g) - 1) * MLVSS concentration in activated sludge at the end of the aerobic tank (mg / L) / 1000. (Note: The difference between the polyphosphate content in the activated sludge at the end of the aerobic tank and the polyphosphate content in the activated sludge at the end of the anaerobic tank is the phosphorus content absorbed by microorganisms during the biological phosphorus removal process. Through multiple laboratory tests, the increase in polyphosphate in activated sludge without biological phosphorus removal is 1 mg / g. This is the phosphorus content adsorbed by the sludge EPS and needs to be deducted when calculating the biological phosphorus removal efficiency.)

[0054] The proportion of biological phosphorus removal in the sewage treatment plant = dissolved phosphorus removed by the biological phosphorus removal (mg / L) / orthophosphate concentration in the total influent of the sewage treatment plant (mg / L) * 100%.

[0055] The beneficial effects of the technical solution of the present invention are as follows:

[0056] (1) For water plants with chemical phosphorus removal agents, conventional methods for judging the biological phosphorus removal efficiency are not applicable. The present invention analyzes the biological phosphorus removal efficiency by analyzing the changes in polyphosphates during the biological phosphorus removal process. The physical and chemical methods are used for detection, which are highly accurate and easy to operate. The biological phosphorus removal efficiency can be quantitatively analyzed, avoiding the errors of traditional analytical methods and eliminating the interference of phosphorus removal agents. Therefore, the method of the present invention can accurately obtain the biological phosphorus removal capacity of the water plant.

[0057] (2) The present invention efficiently integrates the sewage and sludge detection processes. The detection equipment is simple to operate and easy to obtain. Water plant detection personnel can also quickly master it, and it is extremely practical.

[0058] (3) Through the biological phosphorus removal efficiency evaluation system and method of the present invention, the water plant can respond quickly and further improve the biological phosphorus removal capacity of the water plant through operation regulation, while reducing the amount of phosphorus removal agent added to achieve energy saving and consumption reduction.

[0059] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0061] Figure 1 A schematic diagram of a system for evaluating the biological phosphorus removal efficiency of a sewage treatment plant provided by the present invention is shown.

[0062] The following are the descriptions of the reference numerals:

[0063] 1-Sewage storage device, 2-Filtration device, 3-Filtrate storage device, 4-Phosphate online determination device, 5-Activated sludge storage device, 6-Solid-liquid separation device, 7-Sludge washing device, 8-Sludge thermal drying device, 9-Sludge incineration device, 10-MLVSS determination device, 11-Sludge freeze-drying device, 12-Sludge high-temperature oxidation leaching device, 13-Polyphosphate determination device, 14-Computer system. DETAILED DESCRIPTION

[0064] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Instead, these embodiments are provided to make the present invention more thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0065] Example 1

[0066] This embodiment provides a system for evaluating the efficiency of biological phosphorus removal in sewage treatment plants. Figure 1 As shown, the system includes a sewage detection unit, a sludge detection unit and a data analysis and calculation unit;

[0067] The sewage detection unit includes a sewage storage device 1, a valve (not shown), a peristaltic pump (not shown), a filter device 2, a filtrate storage device 3 and a phosphate online measurement device 4 connected in sequence; the phosphate online measurement device is used to measure the orthophosphate concentration of the total influent of the sewage treatment plant and transmit the data to the data analysis and calculation unit;

[0068] The sewage storage device is provided with a sampling port in the middle and a first drain port (not shown) in the lower portion; the filter element pore size of the filter device is 0.45 μm; the filtrate storage device is provided with a first sampling port at the upper portion and a second drain port (not shown) at the bottom; the phosphate online determination device includes a power supply, a display screen, a water inlet, a water outlet, a sampling pump, a phosphate detection reagent, a Hach DR6000 spectrophotometer and a first signal transmission and communication module (not shown); the water inlet and the first sampling port are connected via the sampling pump; the Hach DR6000 spectrophotometer is used to detect the photometric value of the sewage entering the phosphate online determination device after the reaction with the phosphate detection reagent; the first signal transmission and communication module is used to transmit the orthophosphate concentration data of the total influent of the sewage treatment plant to the data analysis and calculation unit;

[0069] The sludge detection unit includes an activated sludge storage device 5, a solid-liquid separation device 6, a sludge elutriation device 7, a sludge thermal drying device 8, a sludge incineration device 9, an MLVSS measuring device 10, a sludge freeze drying device 11, a sludge high temperature oxidation leaching device 12 and a polyphosphate measuring device 13;

[0070] The second sampling port, the solid-liquid separation device and the sludge elutriation device provided at the bottom of the activated sludge storage device are connected in sequence; the outlet of the sludge elutriation device is divided into two routes, one route is connected in sequence to the sludge thermal drying device, the sludge incineration device and the MLVSS measuring device, and the other route is connected in sequence to the sludge freeze drying device, the sludge high-temperature oxidation leaching device and the polyphosphate measuring device;

[0071] The MLVSS measuring device is used to measure the MLVSS concentration of the activated sludge and transmit the data to the data analysis and calculation unit; the polyphosphate measuring device is used to measure the polyphosphate content in the activated sludge and transmit the data to the data analysis and calculation unit;

[0072] The solid-liquid separation device includes a high-speed centrifuge; the sludge elutriation device includes a constant temperature oscillator and a high-speed centrifuge; the sludge thermal drying device includes an electric blast drying oven; the sludge incineration device includes a high-temperature muffle furnace; the MLVSS measurement device includes a second signal transmission and communication module; the sludge freeze drying device includes a freeze dryer; the sludge high-temperature oxidation leaching device includes a high-pressure steam autoclave; the polyphosphate measurement device includes a DR6000 spectrophotometer and a third signal transmission and communication module;

[0073] The volumes of the sewage storage device, the filtrate storage device and the activated sludge storage device are each independently 5L.

[0074] The data analysis and calculation unit is a computer system 14 well known to those skilled in the art.

[0075] This embodiment also provides a method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant, using the system described above, including the following steps:

[0076] S1: The total influent water of the sewage treatment plant is sent to the sewage storage device. The total influent water of the sewage treatment plant in the sewage storage device is sent to the filtration device through a valve and a peristaltic pump for filtration. The flow rate of the peristaltic pump is 500 mL / min, and the set time is 10 minutes.

[0077] After filtration, the wastewater enters the filtrate storage device and then enters the phosphate online determination device. The luminosity value (the total orthophosphate concentration of the sewage treatment plant influent) after the wastewater enters the phosphate online determination device and reacts with the phosphate detection reagent is detected by a DR6000 spectrophotometer and the data is transmitted to the data analysis and calculation unit;

[0078] S2: 500 mL of activated sludge from the end of the aerobic tank is fed into the activated sludge storage device. After the supernatant is removed by the first round of centrifugation (at a speed of 6000 r / min for 20 min), the bottom sludge is fed into the sludge elutriation device. In the sludge elutriation device, the bottom sludge is mixed with water to restore the sludge volume to 500 mL. The resulting sludge-water mixture is then shaken and centrifuged three times to obtain centrifugally elutriated sludge.

[0079] Half of the sludge after centrifugal elutriation is sequentially subjected to thermal drying (105° C., 2 h) and incineration (high-temperature muffle furnace, 600° C., 1 h), and then the MLVSS concentration of the activated sludge at the end of the aerobic tank is measured by the MLVSS measuring device, and the data is transmitted to the data analysis and calculation unit; the remaining half is sequentially subjected to vacuum freeze drying (temperature of −40° C., vacuum degree of 0.12 mbar, time for 24 h) and high-temperature oxidative leaching, and then the polyphosphate content in the activated sludge at the end of the aerobic tank is measured by the polyphosphate measuring device, and the data is transmitted to the data analysis and calculation unit;

[0080] The high-temperature oxidation leaching method comprises: mixing 9 mg of the vacuum freeze-dried sludge with 20 mL of pure water and 8 mL of a potassium persulfate aqueous solution (5% by mass), placing the mixture in a high-pressure steam sterilizer, and oxidizing and leaching the mixture at 120° C. for 30 minutes;

[0081] The method for measuring the polyphosphate content in the activated sludge at the end of the aerobic tank using the polyphosphate measuring device includes: mixing 50 mL of the sludge leached by the high-temperature oxidation with 1 mL of ascorbic acid and 2 mL of ammonium molybdate for color development, and using the DR6000 spectrophotometer to measure the polyphosphate content in the activated sludge at the end of the aerobic tank and transmitting the data to the data analysis and calculation unit.

[0082] S3: Repeat the operation of step S2 for the activated sludge at the end of the anaerobic tank to obtain the MLVSS concentration data of the activated sludge at the end of the anaerobic tank and the polyphosphate content data in the activated sludge at the end of the anaerobic tank;

[0083] S4: A calculation formula is preset in the data analysis and calculation unit, and the proportion of biological phosphorus removal in the sewage treatment plant is calculated using the orthophosphate concentration data of the total influent of the sewage treatment plant, the MLVSS concentration data of the activated sludge at the end of the aerobic tank, the polyphosphate content data in the activated sludge at the end of the aerobic tank, and the polyphosphate content data in the activated sludge at the end of the anaerobic tank.

[0084] The calculation formula includes:

[0085] Dissolved phosphorus removed by biological phosphorus removal (mg / L) = (polyphosphate content in activated sludge at the end of aerobic tank (mg / g) - polyphosphate content in activated sludge at the end of anaerobic tank (mg / g) - 1) * MLVSS concentration of activated sludge at the end of aerobic tank (mg / L) / 1000;

[0086] Note: The difference between the polyphosphate content of the activated sludge at the end of the aerobic tank and the polyphosphate content of the activated sludge at the end of the anaerobic tank is the phosphorus content absorbed by microorganisms during the biological phosphorus removal process; through multiple laboratory tests, it was found that the increase in polyphosphate in the activated sludge without biological phosphorus removal was 1 mg / g, which is the phosphorus content adsorbed by the sludge EPS and needs to be deducted when calculating the biological phosphorus removal efficiency.

[0087] The proportion of biological phosphorus removal in the sewage treatment plant = dissolved phosphorus removed by the biological phosphorus removal (mg / L) / orthophosphate concentration in the total influent of the sewage treatment plant (mg / L) * 100%.

[0088] Repeat steps S1-S4 three times and take the average value. The specific value results are shown in Table 1. The average proportion of biological phosphorus removal in the water plant for the three tests is 39.4%, indicating that the current biological phosphorus removal capacity of the water plant accounts for more than 1 / 3 of the entire phosphorus removal system, which is in line with the general level of sewage treatment plants and the test results are true and reliable.

[0089] The method of the present invention is fast, and through the biological phosphorus removal efficiency evaluation data, the water plant can change the phosphorus removal agent addition strategy according to the daily effluent phosphorus concentration, reduce the agent usage, and avoid excessive addition. In addition, it can also reduce the inhibitory effect of chemical agents on biological phosphorus removal and polyphosphate bacteria, further improving the biological phosphorus removal capacity of the water plant.

[0090] Table 1

[0091]

[0092] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for evaluating the efficiency of biological phosphorus removal in a sewage treatment plant, characterized in that: The system used in this method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant includes a sewage detection unit, a sludge detection unit and a data analysis and calculation unit; The sewage detection unit includes a sewage storage device, a filtering device, a filtrate storage device and a phosphate online measuring device connected in sequence; the phosphate online measuring device is used to measure the orthophosphate concentration of the total influent of the sewage treatment plant and transmit the data to the data analysis and calculation unit; The sludge detection unit includes an activated sludge storage device, a solid-liquid separation device, a sludge elutriation device, a sludge thermal drying device, a sludge incineration device, an MLVSS measuring device, a sludge freeze drying device, a sludge high-temperature oxidation leaching device and a polyphosphate measuring device; The activated sludge storage device, the solid-liquid separation device and the sludge elutriation device are connected in sequence; the outlet of the sludge elutriation device is divided into two routes, one route is connected in sequence to the sludge thermal drying device, the sludge incineration device and the MLVSS measuring device, and the other route is connected in sequence to the sludge freeze drying device, the sludge high-temperature oxidation leaching device and the polyphosphate measuring device; The MLVSS measuring device is used to measure the MLVSS concentration of the activated sludge and transmit the data to the data analysis and calculation unit; the polyphosphate measuring device is used to measure the polyphosphate content in the activated sludge and transmit the data to the data analysis and calculation unit; The method comprises the following steps: S1: The total influent of the sewage treatment plant is sent to the sewage storage device, and after being filtered, it enters the filtrate storage device, and the orthophosphate concentration of the total influent of the sewage treatment plant is measured by the phosphate online measuring device, and the data is transmitted to the data analysis and calculation unit; S2: The activated sludge at the end of the aerobic tank is sent to the activated sludge storage device, and after the first round of centrifugation to remove the supernatant, the bottom sludge is sent to the sludge washing device; In the sludge washing device, the bottom sludge is mixed with water to obtain a sludge-water mixture, which is then shaken and centrifuged a second time to obtain centrifugally washed sludge; Part of the centrifugally elutriated sludge is sequentially subjected to heat drying and incineration, and then the MLVSS concentration of the activated sludge at the end of the aerobic tank is measured by the MLVSS measuring device, and the data is transmitted to the data analysis and calculation unit; the remaining part is sequentially subjected to vacuum freeze drying and high-temperature oxidation leaching, and then the polyphosphate content in the activated sludge at the end of the aerobic tank is measured by the polyphosphate measuring device, and the data is transmitted to the data analysis and calculation unit; The heat drying temperature is 90-120°C and the time is 1.5-2.5h; The incineration temperature is 550-650°C and the time is 0.5-1.5h; The vacuum freeze drying temperature is -35 to -45°C, the vacuum degree is 0.10-0.15 mbar, and the time is 20-40 hours; The high-temperature oxidation leaching method comprises: mixing the vacuum freeze-dried sludge with water and a potassium persulfate aqueous solution, placing the mixture in a high-pressure steam sterilizer, and oxidizing and leaching the mixture at 100-150° C. for 25-35 minutes; S3: Repeat the operation of step S2 for the activated sludge at the end of the anaerobic tank to obtain the MLVSS concentration data of the activated sludge at the end of the anaerobic tank and the polyphosphate content data in the activated sludge at the end of the anaerobic tank; S4: A calculation formula is preset in the data analysis and calculation unit, and the proportion of biological phosphorus removal in the sewage treatment plant is calculated using the orthophosphate concentration data of the total influent of the sewage treatment plant, the MLVSS concentration data of the activated sludge at the end of the aerobic tank, the polyphosphate content data in the activated sludge at the end of the aerobic tank, and the polyphosphate content data in the activated sludge at the end of the anaerobic tank. Steps S1 to S4 are repeated multiple times to obtain an average value. The calculation formula includes: Dissolved phosphorus removed by biological phosphorus removal (mg / L) = (polyphosphate content in activated sludge at the end of aerobic tank (mg / g) - polyphosphate content in activated sludge at the end of anaerobic tank (mg / g) - 1) * MLVSS concentration of activated sludge at the end of aerobic tank (mg / L) / 1000; The proportion of biological phosphorus removal in the sewage treatment plant = dissolved phosphorus removed by biological phosphorus removal (mg / L) / orthophosphate concentration in the total influent of the sewage treatment plant (mg / L) * 100%; The sewage treatment plant has chemical phosphorus removal agents.

2. The method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant according to claim 1, wherein: The volumes of the sewage storage device, the filtrate storage device and the activated sludge storage device are independently 5-10L.

3. The method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant according to claim 1, wherein: The sewage storage device is provided with a sample outlet in the middle and a first drain outlet at the bottom; the sample outlet is connected to the filter device via a valve and a peristaltic pump in sequence; The filtrate storage device is provided with a first sampling port at the top and a second drain port at the bottom; The phosphate online measuring device includes a power supply, a display screen, a water inlet, a water outlet, a sampling pump, a phosphate detection reagent, a first photometer and a first signal transmission and communication module; the water inlet is connected to the first sampling port through the sampling pump; the first photometer is used to detect the photometric value after the sewage entering the phosphate online measuring device reacts with the phosphate detection reagent; the first signal transmission and communication module is used to transmit the orthophosphate concentration data of the total influent of the sewage treatment plant to the data analysis and calculation unit.

4. The method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant according to claim 1, wherein: A second sampling port is provided at the bottom of the activated sludge storage device; The solid-liquid separation device includes a high-speed centrifuge; The sludge washing device includes a constant temperature oscillator and a high-speed centrifuge; The sludge thermal drying device includes an electric heating blast drying box; The sludge incineration device includes a high-temperature muffle furnace; The MLVSS measuring device includes a second signal transmission communication module for transmitting the activated sludge MLVSS concentration data to the data analysis and calculation unit; The sludge freeze-drying device includes a freeze dryer; The sludge high-temperature oxidation leaching device includes a high-pressure steam sterilizer; The polyphosphate determination device includes a second photometer and a third signal transmission and communication module, and the third signal transmission and communication module is used to transmit the polyphosphate content data in the activated sludge to the data analysis and calculation unit.

5. The method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant according to claim 3, wherein: In step S1, The total influent water of the sewage treatment plant in the sewage storage device is sent to the filtering device through a valve and a peristaltic pump for filtration; the flow rate of the peristaltic pump is 400-600 mL / min, and the set time is 8-12 minutes; The method for measuring the orthophosphate concentration of the total influent of a sewage treatment plant by the phosphate online measuring device includes: using the first photometer to detect the photometric value of the sewage entering the phosphate online measuring device after reacting with the phosphate detection reagent and transmitting the data to the data analysis and calculation unit.

6. The method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant according to claim 4, wherein: In step S2, The first round of centrifugation has a rotation speed of 5000-6500 r / min and a time of 15-25 min; The volume of the activated sludge at the end of the aerobic tank subjected to the first round of centrifugation is the same as the volume of the sludge-water mixture; Repeat the shaking and the second round of centrifugation 2-5 times; The ratio of the heat-dried centrifugal elutriated sludge to the freeze-dried centrifugal elutriated sludge is 1:(0.95-1.05); The method for measuring the polyphosphate content in the activated sludge at the end of the aerobic tank by the polyphosphate measuring device includes: mixing the sludge leached by the high-temperature oxidation with ascorbic acid and ammonium molybdate for color development, and using the second photometer to measure the polyphosphate content in the activated sludge at the end of the aerobic tank and transmitting the data to the data analysis and calculation unit.

7. The method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant according to claim 1, wherein: The usage ratio of the vacuum freeze-dried sludge, water and potassium persulfate aqueous solution is 9: (18-22): (6-10) mg / mL / mL.

8. The method for evaluating the biological phosphorus removal efficiency of a sewage treatment plant according to claim 6, wherein: The volume ratio of the high temperature oxidation leaching sludge, ascorbic acid and ammonium molybdate is 50: (0.5-1.5): (1.5-2.5).

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