High-efficiency denitrification method for denitrification deep bed filter with carbon source composite addition

Abstract

The invention belongs to the technical field of sewage and industrial wastewater treatment. The invention provides a high-efficiency denitrification and denitrification method for a denitrification deep bed filter tank with composite carbon source addition, comprising the following steps: step S1, equipment layout; step S2, microbial concentration control in the wastewater retained in the tank after air-water backwashing; step S3, recovery of carbon source addition and effluent flow rate process control in the initial stage of filtration. The invention provides an online particle suspension detector in the water inlet channel of each filter tank, and automatically monitors the particle suspension concentration of the wastewater retained in the tank after air-water backwashing through a PLC control system, thereby ensuring that sufficient microorganisms return to the filter material layer after air-water backwashing, effectively replenishing the microorganisms in the filter material layer, providing a guarantee for the microbial amount for the rapid recovery of the microbial membrane concentration, shortening the recovery time of the microbial membrane concentration, ensuring the efficient utilization of carbon sources and nitrate nitrogen by the microorganisms, and ensuring the effluent water quality.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage and industrial wastewater treatment, and in particular relates to a high-efficiency denitrification method for compositely adding carbon sources to a denitrification deep bed filter. Background Art

[0002] The denitrification deep bed filter is installed with quartz sand filler as the filter medium and carrier for microbial attachment and growth. The suspended particulate matter intercepted by filtration and the microbial bodies of denitrifying microorganisms are filled in the gaps of the quartz sand filter material.

[0003] The growth mode of denitrifying microorganisms in quartz sand filter media is in the form of microbial film, that is, they grow on the surface of quartz sand filter media. Since nutrients are dispersed in the water phase, microorganisms grow on the surface of quartz sand filter media toward the water phase, forming a microbial film of a certain thickness.

[0004] When sufficient suspended particles and microbial film accumulate in the gaps between the quartz sand, the water-passing capacity of the quartz sand filter layer is reduced, and it is necessary to start air-water backwashing to clean the quartz sand filter layer. The air-water backwashing process washes out the suspended particles and microorganisms in the gaps between the quartz sand and discharges them with the wastewater. The air-water backwashing process causes a large loss of microbial film concentration in the filter layer. After resuming filtration, due to insufficient microbial concentration, the nitrate nitrogen in the influent and the added carbon source cannot be effectively treated, and the nitrate nitrogen and COD concentrations in the effluent increase, affecting the effluent water quality.

[0005] In actual applications of denitrifying deep bed filters, multiple filter cells are usually set up. The air-water backwashing of a single filter cell only affects the microbial concentration of the filter cell. According to the current application technology, the microbial membrane concentration of the filter cell is low. After the filtration operation is restored, the microorganisms are not supplemented to the filter cell, and no additional nutrients are added to promote microbial growth. The microbial membrane concentration requires a long recovery time. During the recovery period of the microbial membrane concentration, the effluent COD and nitrate nitrogen concentrations of the filter cell are usually exceeded.

[0006] The key to high-efficiency denitrification and nitrogen removal in a denitrification deep bed filter is to quickly restore the concentration of the microbial membrane after air-water backwashing and shorten the recovery time. Before the concentration of the microbial membrane is restored, the concentrations of nitrate nitrogen and COD in the effluent are often high. The recovery of the concentration of the microbial membrane requires the supplementation of nutrients or microorganisms, and the microorganisms need a certain amount of time to grow to restore the concentration of the microbial membrane.

[0007] The air-water backwashing of the denitrification deep bed filter washes out the microorganisms in the gaps of the quartz sand filter media and disperses them in the wastewater. Some of the microorganisms are discharged with the wastewater, and some are dispersed in the wastewater retained in the pool. Excessive discharge of wastewater is an important factor causing the loss of microorganisms. Wastewater discharge should be strictly controlled to ensure that there are enough microorganisms in the wastewater retained in the pool to return to the filter media layer; if the concentration of suspended particles in the retained wastewater is too high, when the filter tank resumes filtration, the concentration of suspended particles in the effluent will be too high; if the concentration of suspended particles in the retained wastewater is too low, the concentration of microorganisms cannot be effectively supplemented. The current technology does not have the corresponding function to coordinate the contradiction between the increase in the concentration of retained microorganisms and the reaching of the concentration of suspended particles in the effluent.

[0008] For a filter tank that is backwashed with air and water, adding additional nutrients can accelerate the rapid recovery of the concentration of microbial film in the filter layer. Ensuring a certain concentration of microorganisms in the filter layer and then adding additional carbon sources are sufficient and necessary conditions for the effective rapid recovery of the concentration of microbial film. However, when the microbial concentration is not sufficient, the nitrate nitrogen and COD concentrations in the effluent still exceed the standard. The current carbon source addition technology and operation control technology of the denitrification deep bed filter cannot add additional carbon sources, and cannot solve the problem of excessive nitrate nitrogen and COD concentrations in the effluent after additional carbon source addition.

[0009] The main problems are:

[0010] (1) The existing denitrification deep bed filter system cannot control the growth of microorganisms and the quality of effluent water in a single filter cell;

[0011] (2) The current denitrification deep bed filter system is unable to control and online evaluate the concentration of microbial membranes in the filter media after air-water backwashing;

[0012] (3) After the current denitrification deep bed filter system is backwashed with air and water, it is impossible to quickly restore the concentration of the microbial membrane;

[0013] (4) Failure to implement effective control over the effluent quality of the air-water backwash filter, and ignoring the impact of single-cell filter water quality fluctuations on the total effluent quality of the denitrification deep bed filter system;

[0014] The existing denitrification deep bed filter system does not have a professional control method specifically for the high-efficiency denitrification and denitrification technology with composite addition of carbon sources. Summary of the invention

[0015] The present invention provides a high-efficiency denitrification and denitrification method with composite addition of carbon source in a denitrification deep bed filter, which has the advantages of high-efficiency denitrification and denitrification capacity, fully automatic and flexible adjustment of water output, scientific and reasonable carbon delivery technology, etc., thereby solving the technical problems in the prior art that after water backwashing, the concentration of microbial membrane cannot be quickly restored, and the water quality fluctuation of a single filter affects the water quality of the total effluent of the denitrification deep bed filter system.

[0016] The present invention is achieved in that:

[0017] The high-efficiency denitrification and denitrification method with carbon source composite addition in a denitrification deep bed filter comprises the following steps:

[0018] Step S1: Equipment layout,

[0019] The device of this method comprises:

[0020] The carbon source auxiliary dosing device is arranged in the dosing room, including a carbon source dosing variable frequency metering pump arranged for each filter tank of the denitrification deep bed filter tank and an auxiliary carbon source dosing mixing tank arranged behind the water inlet gate of each filter tank;

[0021] Two online particle suspended matter concentration detectors, one installed in the water inlet channel of each filter tank and one installed on the water outlet pipe of each filter tank, for real-time monitoring of the particle suspended matter concentration of the inlet and outlet water of the filter tank;

[0022] The electromagnetic flowmeter is installed at the output end of the water outlet regulating valve of each filter tank outlet pipe to control the water outlet flow.

[0023] The nitrate nitrogen online detector is installed at the outlet end of the water outlet pipe of each filter tank to monitor the nitrate nitrogen concentration of the water outlet of the filter tank in real time;

[0024] A PLC control system is used to connect the above-mentioned devices and independently control and adjust the water flow rate of each filter tank;

[0025] Step S2, controlling the concentration of microorganisms in the wastewater retained in the pool after air-water backwashing;

[0026] When the air-water backwash of each filter tank is started, the concentration of suspended particles in the backwash wastewater is detected in real time by the online suspended particle concentration detector installed in the water inlet channel of the filter tank. The suspended particle concentration shows a trend of first rising and then falling during the air-water backwash process. When the suspended particle concentration reaches the highest point and is in a downward trend, when the real-time detected suspended particle concentration is lower than the suspended particle concentration set in the PLC control system, the PLC control system automatically stops the air-water backwash of the filter tank.

[0027] Step S3, restore the initial carbon source addition and effluent flow process control of the filtration,

[0028] Step S31, adding carbon source in proportion,

[0029] The electromagnetic flowmeter installed at the outlet pipe of each filter tank detects the outlet flow in real time, and works in conjunction with the outlet regulating valve to adjust its opening, and feeds back the flow signal to the PLC control system for proportional calculation of the carbon source dosage;

[0030] Step S32: water outflow flow process control,

[0031] The outflow suspended solids concentration parameter value and outflow nitrate nitrogen concentration parameter value of the PLC control system are respectively set to three setting values: low concentration, medium concentration and high concentration, which are used as numerical references for adjusting the opening of the outflow regulating valve or closing the outflow regulating valve;

[0032] Compare the real-time detected effluent suspended solids concentration or nitrate nitrogen concentration of each filter with the corresponding concentration set value:

[0033] When the effluent suspended solids concentration or nitrate nitrogen concentration is higher than the respective set medium concentration, the effluent flow rate of the filter tank is adjusted to the second lowest flow rate;

[0034] When the detected concentration of suspended solids in the effluent or the concentration of nitrate nitrogen is higher than the high concentration set for each concentration, the effluent flow rate of the filter tank is adjusted to low flow operation or the effluent regulating valve is closed and opened after a delay of the set time;

[0035] When the effluent suspended solids concentration or nitrate nitrogen concentration is lower than the respective set medium concentration, the effluent flow rate of the filter tank is adjusted to the second lowest flow rate;

[0036] When the detected concentration of suspended particulate matter in the effluent or the concentration of nitrate nitrogen is lower than the respective set low concentrations, the effluent flow rate of the filter tank is adjusted to normal flow rate operation.

[0037] Furthermore, in the step S1, the auxiliary carbon source addition mixing tank is provided with a rapid mixing agitator and an auxiliary carbon source addition pipe with an electric ball valve.

[0038] Further, in the step 31, after the gas-water backwash of the filter tank is completed, the water inlet gate is opened at a delayed time until the set time. During the delayed opening time of the water inlet gate, the carbon source is added to the mixing tank behind the water inlet gate according to the carbon source addition flow rate set by the PLC control system. The PLC control system controls the variable frequency metering pump of the corresponding carbon source auxiliary addition device and opens the electric ball valve on the corresponding auxiliary carbon source addition pipeline of the filter tank, and starts the corresponding variable frequency metering pump to add the carbon source at the set flow rate, and at the same time controls the rapid mixing agitator of the auxiliary carbon source addition mixing tank to start;

[0039] After the water inlet gate is opened, the outlet regulating valve is opened according to the set flow rate of the filter tank outlet. The electromagnetic flowmeter on the outlet pipe of the filter tank detects the filter tank outlet flow rate in real time and outputs it to the PLC control system, and adjusts the outlet regulating valve opening through PID to control the filter tank outlet flow rate within the set range.

[0040] The outlet electromagnetic flow meter outputs a signal to the PLC control system. The PLC control system calculates the amount of auxiliary carbon source to be added according to the proportional control setting parameters, and then controls the corresponding variable frequency metering pump to perform carbon source addition.

[0041] Furthermore, in step S32, when the effluent suspended particulate matter and nitrate nitrogen detection concentrations are both lower than the set low concentration and the filter tank effluent flow rate is greater than or equal to the normal flow rate setting value, the effluent flow rate process control ends, the carbon source auxiliary dosing device stops adding carbon source, the rapid mixing agitator of the auxiliary carbon source dosing mixing tank stops running, and the denitrification deep bed filter switches to the normal operation mode.

[0042] The beneficial effects of the present invention are:

[0043] (1) The present invention sets an online particle suspended matter detector in the water inlet channel of each filter tank, and combines the carbon source composite dosing high-efficiency denitrification control technology based on the PLC control system. The PLC control system automatically monitors the particle suspended matter concentration of the wastewater retained in the tank after the air-water backwashing, ensures that a sufficient amount of microorganisms return to the filter material layer after the air-water backwashing, effectively replenishes the microorganisms in the filter material layer, provides a guarantee for the rapid recovery of the microbial membrane concentration, shortens the recovery time of the microbial membrane concentration, ensures the efficient utilization of carbon sources and nitrate nitrogen by microorganisms, and ensures the effluent water quality;

[0044] (2) The present invention embeds PLC control technology into the original denitrification deep bed filter control, reasonably presets PLC control system parameters, configures online monitoring instruments, and uses PID regulation control technology to flexibly control the opening of the outlet regulating valve, thereby achieving efficient denitrification and nitrogen removal in the denitrification deep bed filter and effectively ensuring that the effluent water quality of each filter tank meets the standards;

[0045] (3) The present invention provides a separate carbon source auxiliary dosing device, an auxiliary carbon source dosing mixing tank and a rapid mixing agitator for each filter tank, which are used to auxiliary dosing carbon source after the air-water backwashing of the filter tank is completed, so as to supplement nutrients for microbial growth and promote microbial growth.

[0046] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0048] Figure 1 It is a schematic diagram of the method flow of the present invention;

[0049] Figure 2 It is a schematic diagram of the overall planar structure of the present invention;

[0050] Figure 3 It is a schematic diagram of the structure of the PLC control system of the present invention;

[0051] Figure 4 It is a schematic diagram of the gas-water backwash control process of the present invention;

[0052] Figure 5 This is a flow chart of PID regulation control of filter tank effluent flow rate of the present invention;

[0053] Figure 6 A control flow chart for adjusting the outlet water flow rate according to the concentration of suspended solids in the outlet water particles;

[0054] Figure 7 This is a control flow chart for adjusting the outlet water flow rate according to the outlet nitrate nitrogen concentration.

[0055] Explanation of the reference numerals: 1. Filter tank; 2. Auxiliary carbon source dosing device; 3. Variable frequency metering pump; 4. Auxiliary carbon source dosing mixing tank; 5. Rapid mixing agitator; 6. Electric ball valve; 7. Water inlet gate; 8. Online detector for particle suspended matter concentration; 9. Electromagnetic flowmeter; 10. Water outlet regulating valve; 11. Online detector for nitric nitrogen; 12. PLC control system. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0057] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0058] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0059] Example

[0060] Specific as Figure 1-6 As shown, a high-efficiency denitrification and denitrification method with composite addition of carbon source in a denitrification deep bed filter is provided, comprising the following steps:

[0061] Step S1: Equipment layout,

[0062] The equipment and structure of this method are as follows Figure 1 The main features shown include:

[0063] The carbon source auxiliary dosing device 2 is arranged in the dosing room, and includes a carbon source dosing variable frequency metering pump 3 arranged for each filter tank 1 of the denitrification deep bed filter tank and an auxiliary carbon source dosing mixing tank 4 arranged behind the water inlet gate 7 of each filter tank 1. The auxiliary carbon source dosing mixing tank is provided with a fast mixing agitator 5 and an auxiliary carbon source dosing pipe with an electric ball valve 6, which can fully mix and accurately dosing the carbon source;

[0064] Two online particle suspended matter concentration detectors 8, one installed in the water inlet channel of each filter tank 1 and one installed on the water outlet pipe of each filter tank 1, for real-time monitoring of the particle suspended matter concentration of the inlet and outlet water of the filter tank 1;

[0065] The electromagnetic flowmeter 9 is installed at the output end of the water outlet regulating valve 10 of the water outlet pipeline of each filter tank 1 and is used for controlling the water outlet flow;

[0066] The nitrate nitrogen online detector 11 is installed at the output end of the water outlet pipe of each filter tank 1, and is used to monitor the nitrate nitrogen concentration of the water outlet of the filter tank 1 in real time;

[0067] The PLC control system 12 is used to connect the above-mentioned devices and independently control and adjust the effluent flow rate of each filter tank 1. At the same time, a special control method for high-efficiency denitrification and nitrogen removal by the PLC control system 12 to automatically perform carbon source composite dosing in the denitrification deep bed filter 1 after air-water backwashing of each filter tank 1 is developed;

[0068] The outlet regulating valve 10 is used to adjust the outlet flow rate of each filter tank 1;

[0069] Step S2: Control of microbial concentration in the wastewater retained in the pool after air-water backwashing.

[0070] When the air-water backwashing of each filter tank 1 is started, the concentration of suspended particles in the backwash wastewater is detected in real time by the online suspended particle concentration detector 8 installed in the water inlet channel of the filter tank 1. The suspended particle concentration shows a trend of first rising and then falling during the air-water backwashing process. When the suspended particle concentration reaches the highest point, in the downward trend, when the real-time detected suspended particle concentration is lower than the suspended particle concentration set in the PLC control system 12, the PLC control system 12 automatically stops the air-water backwashing of the filter tank 1, thereby strictly controlling the wastewater discharge to ensure that there are sufficient microorganisms in the wastewater retained in the filter tank 1 to return to the filter material layer, thereby increasing the growth rate of the biofilm on the surface of the filler, thereby effectively solving the problem of the effluent detection data not meeting the standard due to the long recovery period of the filter tank 1 after the air-water backwashing;

[0071] Step S3, restore the initial carbon source addition and effluent flow process control of the filtration,

[0072] Step S31, adding carbon source in proportion,

[0073] The electromagnetic flowmeter 9 installed at the outlet pipe of each filter tank 1 detects the outlet flow in real time, and cooperates with the outlet regulating valve 10 to adjust its opening, and feeds back the flow signal to the PLC control system 12 for calculating the carbon source dosage in proportion;

[0074] After the air-water backwash of a certain filter tank 1 is completed, the water inlet gate 7 is opened according to the delay to the set time. During the delayed opening time of the water inlet gate 7, the carbon source is added to the mixing tank behind the water inlet gate 7 according to the carbon source addition flow rate set by the PLC control system 12. The PLC control system 12 controls the variable frequency metering pump 3 of the corresponding carbon source auxiliary addition device 2 and opens the electric ball valve 6 on the corresponding auxiliary carbon source addition pipeline of the filter tank 1, and starts the corresponding variable frequency metering pump 3 to add the carbon source according to the set flow rate, and at the same time controls the rapid mixing agitator 5 of the auxiliary carbon source addition mixing tank 4 to start;

[0075] After the water inlet gate 7 is opened, the outlet regulating valve 10 is opened according to the set flow rate of the water outlet of the filter tank 1. The electromagnetic flowmeter 9 on the outlet pipe of the filter tank 1 detects the water outlet flow of the filter tank 1 in real time and outputs it to the PLC control system 12, and adjusts the opening of the outlet regulating valve 10 through PID to control the water outlet flow of the filter tank 1 within the set range;

[0076] The outlet electromagnetic flowmeter 9 outputs a signal to the PLC control system 12. The PLC control system 12 calculates the auxiliary carbon source dosage according to the proportional control setting parameters and then controls the corresponding variable frequency metering pump 3 to perform carbon source dosage.

[0077] Step S32: water outflow flow process control,

[0078] The change trend of the detected value of the effluent suspended solids concentration without additional control during the filtration process is: a constant low concentration at the beginning, and a rapid increase after a period of filtration; and the change trend of the detected value of the effluent nitrate nitrogen concentration without additional control during the filtration process is a constant low concentration at the beginning, and a slow increase after a period of filtration;

[0079] The outflow suspended solids concentration parameter value and the outflow nitrate nitrogen concentration parameter value of the PLC control system 12 are respectively set to three setting values: low concentration, medium concentration and high concentration, which are used as numerical references for adjusting the opening of the outflow regulating valve 10 or closing the outflow regulating valve 10;

[0080] Compare the real-time detected effluent suspended solids concentration or nitrate nitrogen concentration of each filter tank 1 with the corresponding concentration set value:

[0081] When the particle suspended matter concentration of the effluent of the filter tank 1 is higher than the set medium concentration of the effluent particle suspended matter concentration, the effluent flow rate of the filter tank 1 is adjusted to the second lowest flow rate operation, the electromagnetic flow meter 9 at the outlet of the filter tank 1 feedbacks the real-time flow signal and compares it with the second lowest flow rate set value, and the PLC control system 12 adjusts the opening of the effluent regulating valve 10 to control the effluent flow rate of the filter tank 1 within the set second lowest flow rate range;

[0082] When the particle suspended matter concentration of the effluent of the grid filter 1 is higher than the set high concentration of the effluent particle suspended matter concentration, the effluent flow rate of the grid filter 1 is adjusted to low flow operation or the effluent regulating valve 10 is closed, and it is reopened after a delay of a set time, and the PLC control system 12 inspects the effluent particle suspended matter concentration detection value and compares it with the particle suspended matter high concentration setting value. When the particle suspended matter concentration of the effluent of the grid filter 1 is still higher than the set high concentration of the effluent particle suspended matter concentration, the effluent flow rate is lowered again or the effluent regulating valve 10 is closed, and the above control process is circulated until the effluent particle suspended matter detection concentration trend is downward and lower than the particle suspended matter concentration set high concentration, and the low flow operation is maintained;

[0083] When the detected concentration of suspended solids in the outlet water is lower than the set medium concentration, the outlet water flow rate is adjusted to the second lowest flow rate.

[0084] When the detected concentration of suspended solids in the outlet water is lower than the set low concentration, the outlet water flow rate is adjusted to operate at normal flow rate.

[0085] At the same time, when the nitrate nitrogen detection concentration of the effluent of the filter tank 1 reaches the medium concentration setting value, the effluent flow rate of the filter tank 1 is adjusted to low flow operation, the electromagnetic flow meter 9 of the filter tank 1 feedbacks the real-time flow signal and compares it with the set low flow rate, and the PLC control system 12 adjusts the opening of the effluent regulating valve 10 to control the effluent flow rate of the filter tank 1 within the set second low flow rate range;

[0086] When the nitrate-nitrogen detection concentration of the outlet water of the filter tank 1 reaches the high concentration setting value, the outlet water regulating valve 10 is closed and reopened after a delay of a set time. The PLC control system 12 inspects the outlet water nitrate-nitrogen detection value and compares it with the high concentration setting value. If the outlet water nitrate-nitrogen detection concentration is still higher than the high concentration setting value, the regulating valve is closed again and reopened after a delay of a set time. The above control process is repeated until the outlet water nitrate-nitrogen detection concentration tends to be lower than the high concentration setting value, and the second lowest flow rate is maintained. When the outlet water nitrate-nitrogen detection concentration tends to be lower than the medium concentration setting value, the outlet water flow of the filter tank 1 is adjusted to the second lowest flow rate. When the outlet water nitrate-nitrogen detection concentration is lower than the low concentration setting value, the outlet water flow of the filter tank 1 is restored to the normal flow rate.

[0087] When the detected concentrations of suspended particulate matter and nitrate nitrogen in the effluent are both lower than the set low concentration and the effluent flow rate of filter tank 1 is greater than or equal to the conventional flow rate setting value, the dedicated control logic of the high-efficiency denitrification and denitrification technology of carbon source composite addition in denitrification deep bed filter tank 1 ends, the carbon source auxiliary dosing device 2 stops adding carbon source, the rapid mixing agitator 5 of the auxiliary carbon source dosing mixing tank 4 stops running, and the denitrification deep bed filter tank 1 switches to the conventional operation mode.

[0088] By comparing the above-mentioned actual detection concentration value with the preset concentration value, the PLC control system 12 can automatically switch between low flow, sub-low flow and normal flow, wherein the effluent particle suspended matter detection concentration or nitrate nitrogen concentration value only needs any one of the data to meet the switching standard, and the PLC control system 12 will execute the switching operation. It has high adjustment sensitivity and can accurately control the effluent COD and nitrate nitrogen concentrations, effectively control the single-cell filter 1, prevent the effluent from exceeding the standard, and thus effectively ensure that the effluent water quality meets the standard.

[0089] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to a specific order or hierarchy.

[0090] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0091] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. A highly efficient denitrification and denitrification method with composite addition of carbon source in a denitrification deep bed filter, characterized in that: The following steps are involved: Step S1: Equipment layout, The device of this method comprises: The carbon source auxiliary dosing device is arranged in the dosing room, including a carbon source dosing variable frequency metering pump arranged for each filter tank of the denitrification deep bed filter tank and an auxiliary carbon source dosing mixing tank arranged behind the water inlet gate of each filter tank; Two online particle suspended matter concentration detectors, one installed in the water inlet channel of each filter tank and one installed on the water outlet pipe of each filter tank, for real-time monitoring of the particle suspended matter concentration of the inlet and outlet water of the filter tank; The electromagnetic flowmeter is installed at the output end of the water outlet regulating valve of each filter tank outlet pipe to control the water outlet flow. The nitrate nitrogen online detector is installed at the outlet end of the water outlet pipe of each filter tank to monitor the nitrate nitrogen concentration of the water outlet of the filter tank in real time; A PLC control system is used to connect the above-mentioned devices and independently control and adjust the water flow rate of each filter tank; Step S2: Control of microbial concentration in the wastewater retained in the pool after air-water backwashing. When the air-water backwash of each filter tank is started, the concentration of suspended particles in the backwash wastewater is detected in real time by the online suspended particle concentration detector installed in the water inlet channel of the filter tank. The suspended particle concentration shows a trend of first rising and then falling during the air-water backwash process. When the suspended particle concentration reaches the highest point and is in a downward trend, when the real-time detected suspended particle concentration is lower than the suspended particle concentration set in the PLC control system, the PLC control system automatically stops the air-water backwash of the filter tank. Step S3, restore the initial carbon source addition and effluent flow process control of the filtration, Step S31, adding carbon source in proportion, The electromagnetic flowmeter installed at the outlet pipe of each filter tank detects the outlet flow in real time, and works in conjunction with the outlet regulating valve to adjust its opening, and feeds back the flow signal to the PLC control system for proportional calculation of the carbon source dosage; Step S32: water outflow flow process control, The outflow suspended solids concentration parameter value and outflow nitrate nitrogen concentration parameter value of the PLC control system are respectively set to three setting values: low concentration, medium concentration and high concentration, which are used as numerical references for adjusting the opening of the outflow regulating valve or closing the outflow regulating valve; Compare the real-time detected effluent suspended solids concentration or nitrate nitrogen concentration of each filter with the corresponding concentration set value: When the effluent suspended solids concentration or nitrate nitrogen concentration is higher than the respective set medium concentration, the effluent flow rate of the filter tank is adjusted to the second lowest flow rate; When the detected concentration of suspended solids in the effluent or the concentration of nitrate nitrogen is higher than the high concentration set for each concentration, the effluent flow rate of the filter tank is adjusted to low flow operation or the effluent regulating valve is closed and opened after a delay of the set time; When the effluent suspended solids concentration or nitrate nitrogen concentration is lower than the respective set medium concentration, the effluent flow rate of the filter tank is adjusted to the second lowest flow rate; When the detected concentration of suspended particulate matter in the effluent or the concentration of nitrate nitrogen is lower than the respective set low concentrations, the effluent flow rate of the filter tank is adjusted to normal flow rate operation.

2. The high-efficiency denitrification and denitrification method with composite addition of carbon source in a denitrification deep bed filter according to claim 1, characterized in that: In the step S1, the auxiliary carbon source addition mixing tank is provided with a rapid mixing agitator and an auxiliary carbon source addition pipe with an electric ball valve.

3. The high-efficiency denitrification and denitrification method with composite addition of carbon source in a denitrification deep bed filter according to claim 2, characterized in that: In the step S31, after the gas-water backwash of the filter tank is completed, the water inlet gate is opened at a delayed time until the set time. During the delayed opening time of the water inlet gate, the carbon source is added to the mixing tank behind the water inlet gate according to the carbon source addition flow rate set by the PLC control system. The PLC control system controls the variable frequency metering pump of the corresponding carbon source auxiliary addition device and opens the electric ball valve on the corresponding auxiliary carbon source addition pipeline of the filter tank, and starts the corresponding variable frequency metering pump to add the carbon source at the set flow rate, and at the same time controls the rapid mixing agitator of the auxiliary carbon source addition mixing tank to start; After the water inlet gate is opened, the outlet regulating valve is opened according to the set flow rate of the filter tank outlet. The electromagnetic flowmeter on the outlet pipe of the filter tank detects the filter tank outlet flow rate in real time and outputs it to the PLC control system, and adjusts the outlet regulating valve opening through PID to control the filter tank outlet flow rate within the set range. The outlet electromagnetic flow meter outputs a signal to the PLC control system. The PLC control system calculates the amount of auxiliary carbon source to be added according to the proportional control setting parameters, and then controls the corresponding variable frequency metering pump to perform carbon source addition.

4. The high-efficiency denitrification and denitrification method with composite addition of carbon source in a denitrification deep bed filter according to claim 1, characterized in that: In step S32, when the detected concentrations of suspended particulate matter and nitrate nitrogen in the effluent are both lower than the set low concentration and the effluent flow rate of the filter tank is greater than or equal to the normal flow rate setting value, the effluent flow rate process control ends, the carbon source auxiliary dosing device stops adding carbon source, the rapid mixing agitator of the auxiliary carbon source dosing mixing tank stops running, and the denitrification deep bed filter tank switches to the normal operation mode.

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