Device and method for treating low carbon-nitrogen ratio sewage by intelligent shunt multi-stage oxygen process

Abstract

This application belongs to the field of wastewater biological treatment technology and discloses an apparatus and method for treating low carbon-to-nitrogen ratio wastewater using an intelligent diversion multi-stage aerobic process. This solves the problems of low carbon source utilization, high energy consumption, poor nitrogen removal stability, and narrow applicability in existing technologies. The apparatus includes pretreatment, intelligent diversion, reaction, advanced treatment, sludge circulation, and an intelligent control unit. The reaction unit consists of a segmented first low-oxygen aerobic tank, an enhanced anoxic tank, a second aerobic tank, and a sedimentation tank connected sequentially. The intelligent diversion unit can dynamically adjust the diversion ratio according to the influent water quality. The first low-oxygen aerobic tank is equipped with an acclimatization and enhancement zone and a reaction zone. The anoxic tank contains a slow-release carbon source carrier, and the second aerobic tank is equipped with a high-efficiency aeration system. Each unit is equipped with an online water quality monitoring module that is linked to the intelligent control unit.

Description

Technical Field

[0001] This application belongs to the field of wastewater biological treatment technology, specifically involving an intelligent diversion-type multi-stage oxygen process for treating wastewater with a low carbon-to-nitrogen ratio. It is applicable to the efficient treatment of various types of wastewater with a low carbon-to-nitrogen ratio, such as urban domestic sewage, food processing wastewater, and dyeing and printing wastewater, and is especially suitable for wastewater treatment scenarios with scarce carbon sources and high nitrogen removal difficulty. Background Technology

[0002] With the acceleration of urbanization and industrial transformation and upgrading in my country, wastewater discharge continues to increase. Influenced by factors such as residents' living habits, leakage in municipal pipe networks, and the mixing of industrial wastewater, wastewater treatment plant influent generally exhibits a low carbon-to-nitrogen ratio (C / N < 4.0), posing a significant challenge to wastewater denitrification. Traditional biological denitrification processes (such as AAO and SBR processes) suffer from problems such as low carbon source utilization, the need for additional external carbon sources, high aeration energy consumption, unstable denitrification efficiency, and poor sludge settling performance when treating wastewater with low C / N ratios. This results in persistently high wastewater treatment costs and makes it difficult to meet increasingly stringent pollutant discharge standards.

[0003] Existing technologies, such as the publicly disclosed SLOAO process for treating urban wastewater with low carbon-to-nitrogen ratios, achieve nitrogen removal through wastewater diversion and short-cut nitrification / denitrification, which reduces energy consumption and carbon source consumption to some extent. However, they still have many limitations: First, they lack effective pretreatment and water quality control mechanisms. When the influent water quality fluctuates greatly, the difficulty of short-cut nitrification acclimatization increases, and the nitrogen removal efficiency becomes unstable. Second, the influent diversion ratio uses a fixed calculated value and cannot be dynamically adjusted according to real-time water quality, resulting in insufficient utilization of carbon sources. Third, the reaction tank structure is simple, the reproduction rate of short-cut nitrifying bacteria is slow, and the acclimatization period is long. Fourth, the carbon source supply in the anoxic tank is prone to insufficiency, requiring reliance on the raw water carbon source, making it difficult to cope with carbon source fluctuation scenarios. Fifth, there is no advanced treatment unit, making it difficult for the effluent water quality to meet higher discharge standards. Sixth, there is a lack of intelligent control systems, and operating parameters need to be manually adjusted, which is cumbersome and makes it difficult to achieve optimal operating conditions.

[0004] Furthermore, existing processes have a narrow scope of application, mainly targeting urban domestic sewage, and are poorly adaptable to industrial wastewater with low carbon-to-nitrogen ratios. Moreover, the sludge return system lacks precise control, easily leading to sludge accumulation or loss, thus affecting treatment efficiency. Therefore, developing a new wastewater treatment process and device that achieves intelligent control, efficient carbon source utilization, low energy consumption, high nitrogen removal efficiency, and wide applicability is key to solving the challenge of treating wastewater with low carbon-to-nitrogen ratios. Summary of the Invention

[0005] The purpose of this application is to overcome the shortcomings of the existing technology and provide an intelligent diversion-type multi-stage oxygen process for treating wastewater with a low carbon-to-nitrogen ratio. This solves the technical problems of low carbon source utilization, high energy consumption, poor denitrification stability, narrow applicability, and cumbersome operation in the existing process. It achieves efficient, energy-saving, and stable treatment of wastewater with a low carbon-to-nitrogen ratio without the need for additional external carbon sources, thereby reducing wastewater treatment costs and improving effluent quality.

[0006] To achieve the above objectives, this application adopts the following technical solution: The device for treating low carbon-to-nitrogen ratio wastewater using an intelligent diversion multi-stage oxygen process includes a pretreatment unit, an intelligent diversion unit, a reaction unit, an advanced treatment unit, a sludge recycling unit, and an intelligent control unit connected in sequence.

[0007] The pretreatment unit is used to remove suspended solids and large particulate impurities from wastewater, stabilize the influent water quality, and prevent impurities from damaging subsequent reaction units and equipment. It also regulates the influent pH and temperature to provide a suitable environment for microbial reactions. It includes a screen, an equalization tank, and a water pretreatment module. The screen is a fine screen with a pore size of 0.5–1.0 mm, which can effectively remove hair, fibers, and large particulate matter from the wastewater. The equalization tank volume is designed according to the influent flow rate, with a retention time of 4–8 hours. It is equipped with a submersible agitator to ensure uniform water quality and prevent pollutant sedimentation. The water pretreatment module includes a pH adjustment device and a temperature control device. The pH adjustment device adjusts the wastewater pH to 7.0–8.0 by adding acidic or alkaline agents (such as sodium hydroxide or sulfuric acid). The temperature control device uses heating or cooling methods to stabilize the wastewater temperature at 18–28°C. Both are electrically connected to an intelligent control unit for automatic regulation. The equalization tank is also equipped with an online water quality monitoring instrument to monitor parameters such as COD, NH3-N, TN, TP, water temperature, and pH in real time, and the monitoring data is transmitted to the intelligent control unit in real time.

[0008] The intelligent diversion unit is one of the core improvements of this application. It is used to dynamically adjust the influent flow ratio based on real-time influent water quality, ensuring full utilization of carbon sources and efficient short-cut nitrification and denitrification. It includes a diversion pipe, an intelligent diversion valve, and a flow monitoring module. One end of the diversion pipe is connected to the effluent outlet of the pretreatment unit, and the other end is connected to the first low-oxygen aerobic tank and the anoxic tank of the reaction unit, respectively. The intelligent diversion valve is an electrically adjustable valve. The flow monitoring module includes two flow meters, respectively installed on the diversion pipes leading to the first low-oxygen aerobic tank and the anoxic tank, for real-time monitoring of the diversion flow rate. Both the intelligent diversion valve and the flow monitoring module are electrically connected to the intelligent control unit. The intelligent control unit dynamically calculates the influent flow ratio r based on the influent parameters collected by the online water quality monitoring instrument, and then adjusts the opening of the intelligent diversion valve to ensure the optimal proportion of wastewater entering the first low-oxygen aerobic tank and the anoxic tank.

[0009] The reaction unit is the core area of ​​wastewater treatment, used to achieve short-cut nitrification, short-cut denitrification, phosphorus uptake and organic matter removal. It includes a first low-oxygen aerobic tank, an anoxic tank, a second aerobic tank and a sedimentation tank connected in sequence.

[0010] The first low-oxygen aerobic tank is divided into a pre-acclimation and enhancement zone and a post-reaction zone, with a guide plate between the two zones. The guide plate has evenly distributed guide holes with a diameter of 10-15 mm to ensure slow wastewater flow, sufficient reaction, and avoid short-circuiting. The acclimation and enhancement zone contains an ammonia-oxidizing bacteria carrier made of porous ceramic, characterized by a large specific surface area, good adsorption performance, and excellent biocompatibility. The ammonia-oxidizing bacteria loading is 5-8 g / L, which can rapidly enrich short-range nitrifying bacteria, shorten the acclimation period, and increase the nitrite accumulation rate. The reaction zone is equipped with a submersible mixer and microporous aerators. The microporous aerators are evenly distributed at the bottom of the tank, ensuring uniform aeration, high oxygen utilization, and effective control of dissolved oxygen concentration. The first low-oxygen aerobic tank is equipped with an online dissolved oxygen monitor and a sludge concentration monitor to monitor dissolved oxygen and sludge concentrations in real time. The data is transmitted to an intelligent control unit for adjusting aeration intensity and sludge return ratio.

[0011] The anoxic tank features an enhanced design with a built-in slow-release carbon source carrier and a high-efficiency stirring device. The slow-release carbon source carrier is a modified corn stalk-activated carbon composite carrier, which, after high-temperature carbonization and activation treatment, possesses excellent slow-release performance, long service life, and environmental friendliness. The filling volume is 15%–25% of the effective volume of the anoxic tank, with a carrier particle size of 5–10 mm and a slow-release cycle of 30–60 days. It can be replenished or replaced periodically, meeting the carbon source requirements of short-cut denitrification without the need for additional external carbon source addition. The high-efficiency stirring device is a submersible double-impeller agitator with adjustable stirring intensity, ensuring uniform carbon source release while allowing sufficient contact between wastewater, microorganisms, and the carrier, thus improving reaction efficiency. An online dissolved oxygen monitor is installed in the anoxic tank to control the dissolved oxygen concentration below 0.5 mg / L, providing a suitable environment for short-cut denitrification.

[0012] The second aerobic tank is equipped with a high-efficiency aeration system, featuring pulse-type aeration pipes arranged in a ring at the bottom. The aeration frequency is 30–60 seconds per cycle. Pulse aeration effectively prevents sludge settling while improving oxygen utilization and reducing aeration energy consumption. An external variable-frequency blower is connected to the aeration pipes. Based on data from the online dissolved oxygen monitor in the second aerobic tank, the blower automatically adjusts the aeration rate, maintaining the dissolved oxygen concentration within the tank at 1.6–2.2 mg / L to ensure smooth phosphorus uptake by polyphosphate-accumulating bacteria and deep removal of organic matter. A sludge concentration monitor is also installed in the second aerobic tank to monitor sludge concentration in real time.

[0013] The sedimentation tank is a vertical flow sedimentation tank with an effluent weir at the top to collect the treated supernatant. A sludge discharge outlet and a sludge return outlet are located at the bottom. The sludge discharge outlet is used to periodically discharge excess sludge, and the sludge return outlet is used to connect to the sludge circulation unit for sludge recirculation. A sludge interface monitor is installed inside the sedimentation tank to monitor the sludge interface height in real time, preventing sludge loss or accumulation.

[0014] The advanced treatment unit further improves the effluent quality, ensuring that the effluent meets preset discharge standards and can be directly discharged or reused. It includes an ultrafiltration membrane module and a disinfection module. The ultrafiltration membrane module uses a hollow fiber ultrafiltration membrane with a pore size of 0.01–0.1 μm, effectively removing suspended solids, colloids, microorganisms, and residual pollutants from the water. The operating pressure is 0.1–0.3 MPa, and the membrane flux is 10–20 L / (m³). 2 •h), perform backwashing regularly, with a backwash cycle of 30-60 minutes and a backwashing time of 5-10 minutes, which can effectively extend the service life of the membrane. The disinfection module uses ultraviolet disinfection, with a disinfection dose of 15-30 mJ / cm². 2 It can effectively kill bacteria, viruses and other microorganisms in the water, ensuring that the microbial indicators of the effluent meet the standards.

[0015] The sludge recycling unit is used to achieve sludge recycling, improve the efficiency of short-cut nitrification, and control the sludge concentration. It includes a sludge return pump and a sludge concentration monitor. The sludge return pump is a variable frequency pump, connected at one end to the sludge return port at the bottom of the sedimentation tank and at the other end to the acclimatization and enhancement zone of the first low-oxygen aerobic tank. It can return activated sludge from the sedimentation tank to the first low-oxygen aerobic tank to replenish the sludge concentration and enhance the short-cut nitrifying bacteria community. The sludge concentration monitor is installed in the first low-oxygen aerobic tank to monitor the sludge concentration in real time. When the sludge concentration is below 3000 mg / L or above 5000 mg / L, the intelligent control unit adjusts the speed of the sludge return pump to control the sludge return ratio at 60%–100%, ensuring that the sludge concentration is stable between 3000 and 5000 mg / L. Excess sludge is discharged periodically from the sludge discharge port at the bottom of the sedimentation tank, with a discharge frequency of 1 to 2 times per day. The discharge volume is adjusted according to the sludge concentration and treatment effect to avoid sludge aging.

[0016] The intelligent control unit is another core improvement of this application, used to realize the automated and intelligent operation of the entire device, improve processing efficiency, and reduce operational difficulty. It includes a controller, a data acquisition module, and a remote monitoring module. The data acquisition module connects to the online monitoring instruments of each unit (water quality, dissolved oxygen, sludge concentration, flow rate, sludge interface, etc.) to collect operating parameters in real time and transmit the data to the controller. The controller uses a PLC controller with built-in preset control logic and calculation models. Based on the collected parameters, it can dynamically calculate the influent flow ratio r and sludge return ratio, and coordinate the control of the operating parameters of equipment such as the intelligent diversion valve, stirring device, blower, sludge return pump, pH adjustment device, and temperature adjustment device. The remote monitoring module enables remote data viewing, parameter setting, and equipment control, facilitating remote operation and maintenance by staff and timely handling of abnormal situations.

[0017] Furthermore, the dissolved oxygen concentration in both the acclimatization and reaction zones of the first low-oxygen aerobic tank is controlled at 0.4–0.8 mg / L. This concentration range effectively inhibits the growth of nitrifying bacteria and promotes the reproduction of ammonia-oxidizing bacteria, achieving short-cut nitrification. The dissolved oxygen concentration in the second aerobic tank is controlled at 1.6–2.2 mg / L, which meets the requirements for phosphorus uptake by polyphosphate-accumulating bacteria and deep removal of organic matter. The first low-oxygen aerobic tank is inoculated with activated sludge and ammonia-oxidizing bacteria inoculant. After acclimatization, the cumulative nitrite nitrogen rate in the wastewater reaches 60% or more. The wastewater after short-cut nitrification is mixed with the wastewater transported to the anoxic tank by the intelligent diversion unit. Short-cut denitrification and phosphorus release by polyphosphate-accumulating bacteria are completed in the anoxic tank. Then, the wastewater undergoes phosphorus uptake and deep removal of organic matter in the second aerobic tank, solid-liquid separation in the sedimentation tank, and deep treatment to obtain compliant water.

[0018] A method for treating low C / N ratio wastewater using an intelligent diversion multi-stage oxygen process, employing the aforementioned device for wastewater treatment, specifically includes the following steps: Step 1: Pretreatment and Water Quality Control; After large particulate suspended solids and impurities are removed by the screen, urban low carbon-to-nitrogen ratio wastewater enters the equalization tank. The intelligent control unit controls the operation of the pH and temperature adjustment devices based on the pH and temperature data collected by the online water quality monitoring instrument, adjusting the wastewater pH to 7.0-8.0 and stabilizing the temperature at 18-28℃. The stirring device continuously stirs to ensure uniform water quality. The online water quality monitoring instrument collects parameters such as COD, NH3-N, TN, and TP of the influent in real time and transmits them to the intelligent control unit.

[0019] Step 2: Intelligent Diversion Ratio Calculation and Control; Based on the influent parameters collected in Step 1 and the preset effluent TN discharge standard, the intelligent control unit dynamically calculates the influent diversion ratio r (the proportion of wastewater entering the first low-oxygen aerobic tank to the total influent volume) using a built-in calculation model. The formula for calculating the influent diversion ratio r is: The definitions of each parameter in the formula and the organic matter removal rate of the first low-oxygen aerobic tank. The calculation formula is consistent with that of claim 8. The intelligent control unit recalculates the diversion ratio r every 1 to 2 hours. By adjusting the opening of the intelligent diversion valve, the wastewater is proportionally transported to the first low-oxygen aerobic tank and the anoxic tank, ensuring full utilization of the carbon source and efficient short-cut nitrification and denitrification reactions.

[0020] Step 3: Short-cut nitrification acclimatization and reaction; Activated sludge from the traditional process is inoculated into the acclimatization and enhancement zone of the first low-oxygen aerobic tank at an inoculation concentration of 3500–4500 mg / L. After 24 hours of aeration to activate the sludge activity, ammonia-oxidizing bacteria are added. The intelligent control unit controls the aeration intensity and the operation of the stirring device to stabilize the dissolved oxygen concentration in the acclimatization and enhancement zone and the reaction zone at 0.4–0.8 mg / L, the hydraulic retention time at 2.5–4.5 hours, and the sludge concentration at 3000–5000 mg / L. The short-cut nitrifying bacteria community is enhanced through the bacteria carrier in the acclimatization and enhancement zone. The effluent nitrite concentration is continuously monitored. When the cumulative nitrite rate remains stable at 60% or higher for 3 consecutive days, the short-cut nitrification acclimatization is complete. After acclimatization, the wastewater enters the reaction zone for continuous short-cut nitrification, converting ammonia nitrogen to nitrite nitrogen while removing some organic matter. The reacted wastewater then enters the anoxic tank through a baffle plate.

[0021] Step 4: Short-cut denitrification and phosphorus release; Wastewater from the first low-oxygen aerobic tank enters the anoxic tank and mixes with another portion of wastewater directly transported to the anoxic tank by the intelligent diversion unit. The slow-release carbon source carrier in the anoxic tank slowly releases carbon source. The intelligent control unit controls the stirring device to ensure sufficient contact between the wastewater, microorganisms, and carbon source carrier. The hydraulic retention time in the anoxic tank is controlled at 3.5–5.5 hours, the sludge concentration is stabilized at 3000–5000 mg / L, and the dissolved oxygen concentration in the tank is below 0.5 mg / L. Microorganisms use nitrite generated from short-cut nitrification as an electron acceptor and the slow-release carbon source as an electron donor to carry out short-cut denitrification, converting nitrite into nitrogen gas, thus achieving denitrification. Simultaneously, polyphosphate-accumulating bacteria complete the phosphorus release process under anoxic conditions, preparing for subsequent phosphorus uptake.

[0022] Step 5: Phosphorus Absorption and Deep Removal of Organic Matter; After the reaction in the anoxic tank, the wastewater is transported to the second aerobic tank. The intelligent control unit, based on data from the online dissolved oxygen meter, controls the operation of the variable frequency blower, adjusting the dissolved oxygen concentration in the tank to 1.6–2.2 mg / L via pulse-type aeration pipes, controlling the hydraulic retention time to 2.5–4.5 hours, and stabilizing the sludge concentration at 3000–5000 mg / L. Microorganisms in the second aerobic tank deeply remove residual organic matter from the wastewater. Simultaneously, polyphosphate-accumulating bacteria absorb large amounts of phosphorus in an aerobic environment, converting it into their own cellular components, thus achieving phosphorus removal.

[0023] Step 6: Solid-liquid separation and sludge recycling; the wastewater after the reaction in the second aerobic tank enters the sedimentation tank for solid-liquid separation, and the supernatant enters the deep treatment unit through the effluent weir; part of the settled sludge is returned to the acclimatization and enhancement zone of the first low-oxygen aerobic tank through the sludge return pump. The intelligent control unit dynamically adjusts the sludge return ratio to 60% to 100% based on the data collected by the sludge concentration monitor to ensure the sludge concentration in the first low-oxygen aerobic tank is stable; the other part is treated as surplus sludge and is discharged periodically through the sludge discharge outlet at a frequency of 1 to 2 times per day, with the discharge volume adjusted according to the sludge concentration and treatment effect.

[0024] Step 7: Advanced Treatment and Compliance Discharge; The supernatant from the sedimentation tank enters the ultrafiltration membrane module. Under an operating pressure of 0.1–0.3 MPa, suspended solids, colloids, microorganisms, and residual pollutants in the water are removed through the ultrafiltration membrane. The membrane flux is controlled at 10–20 L / (m³). 2 •h), backwashing is performed regularly to ensure the treatment efficiency of the membrane module. Wastewater treated by the ultrafiltration membrane enters the disinfection module for ultraviolet disinfection at a dosage of 15–30 mJ / cm³. 2 It kills bacteria, viruses and other microorganisms in the water, and the treated wastewater meets the preset discharge standards for direct discharge or reuse.

[0025] Beneficial effects Compared with the prior art, the beneficial effects of this application are as follows: 1. Structural innovation and functional upgrade: The addition of a pretreatment unit and a deep treatment unit. The pretreatment unit can stabilize the influent water quality and remove impurities to avoid affecting subsequent reactions. The deep treatment unit significantly improves the effluent water quality through ultrafiltration membrane and ultraviolet disinfection, which can meet higher discharge standards and even achieve wastewater reuse, breaking through the limitation of the original patent that did not have deep treatment.

[0026] 2. Intelligent control and improved efficiency: The system is equipped with an intelligent control unit and an intelligent diversion unit, which can dynamically adjust the influent diversion ratio, sludge return ratio, aeration intensity and other operating parameters according to the real-time influent water quality. The diversion ratio calculation results are updated every 1 to 2 hours to ensure that the process is always in the optimal operating state. This solves the problem of fixed diversion ratio and manual adjustment of operating parameters in the original patent, making the operation more convenient and the treatment efficiency more stable.

[0027] 3. Bio-enhanced, shortened acclimatization cycle: The first low-oxygen aerobic tank adopts a segmented design, adds an acclimatization enhancement zone and incorporates ammonia-oxidizing bacteria carriers, which can rapidly enrich short-range nitrifying bacteria, shortening the short-range nitrification acclimatization cycle from the original patented 28 days to 15-20 days, increasing the nitrite accumulation rate to 60% or more, and significantly improving the efficiency of short-range nitrification reaction.

[0028] 4. Highly efficient utilization of carbon source, no need for external addition: The anoxic tank has a built-in modified corn stalk-activated carbon composite slow-release carbon source carrier, which can slowly release carbon source, making full use of the carbon source in the raw water while supplementing the carbon source required for denitrification. There is no need to add external carbon source, reducing reagent consumption and solving the problem of unstable carbon source supply and dependence on raw water carbon source of the original patent.

[0029] 5. Reduced energy consumption and increased carbon emissions: The second aerobic tank adopts pulse aeration + variable frequency blower, which improves oxygen utilization by more than 30% and reduces aeration energy consumption by 20% to 30%; the nitrification liquid return step of the traditional process is eliminated, reducing the energy consumption of the return pump; the sludge recycling system is precisely controlled to avoid sludge waste, further reducing operating costs and achieving carbon reduction and efficiency improvement in wastewater treatment.

[0030] 6. Expanded Scope of Application: Through water pretreatment, biological enhancement and intelligent control, this application is not only applicable to urban domestic sewage, but also to various industrial wastewater with low carbon-to-nitrogen ratios such as food processing and dyeing. The influent C / N ratio can be as low as 2.0, and the denitrification efficiency can be increased to more than 90%, breaking through the limitation of the narrow scope of application of the original patent.

[0031] 7. Stable operation and strong shock resistance: Each unit is equipped with an online monitoring module, and the intelligent control unit can respond to water quality and quantity fluctuations in real time and adjust operating parameters in a timely manner, significantly improving shock resistance and solving the problem that the treatment effect of the original patent is greatly affected by fluctuations in influent. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a line graph showing the change in the cumulative nitrite nitrogen rate in the effluent of the first low-oxygen aerobic tank of the present invention. Figure 2 This is a line graph of the present invention; Figure 3 This is a bar chart of the present invention. Detailed Implementation

[0034] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0035] It is important to note that terms such as "first," "second," "symmetric," and "array" are used only to distinguish between descriptive and positional descriptions and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features specified with terms such as "first" or "symmetric" may explicitly or implicitly include one or more of that feature; similarly, when the quantity of certain features is not limited by words such as "two" or "three," it should be noted that such features also explicitly or implicitly include one or more features. In this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," and "fixation" should be interpreted broadly; for example, they can refer to a fixed connection, a detachable connection, or an integral molding; they can refer to a mechanical connection, a direct connection, a welding connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the accompanying drawings and specific circumstances.

[0036] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Example 1

[0037] This embodiment uses the ISLOAO process device and method described in this application to treat low carbon-to-nitrogen ratio wastewater from a municipal wastewater treatment plant. The specific steps are as follows: Step 1: Pretreatment and water quality control; After large suspended solids are removed by a screen (0.8mm aperture), the wastewater enters the equalization tank, where it remains for 6 hours. The intelligent control unit controls the pH adjustment device to adjust the pH value of the wastewater to about 7.5, the temperature adjustment device stabilizes the temperature at 22-25℃, the stirring device continuously stirs, and the online water quality monitoring instrument collects the influent parameters in real time: COD 230-290mg / L, NH3-N 38-49mg / L, TN 42-53mg / L, TP 4.9-7.1mg / L, and C / N ratio 2.8-3.7.

[0038] Step 2: Intelligent diversion ratio calculation and control; The preset effluent TN discharge standard is 8 mg / L. The intelligent control unit calculates the influent diversion ratio r as 0.70 to 0.82 based on the influent parameters, and takes the average diversion ratio of 0.76. The sewage is then transported to the first low-oxygen aerobic tank and the anoxic tank at a ratio of 76% and 24% respectively through the intelligent diversion valve. The diversion ratio is recalculated every 1.5 hours, and the opening of the diversion valve is dynamically adjusted.

[0039] Step 3: Short-cut nitrification acclimatization and reaction; Sludge from a wastewater treatment plant was returned, screened to remove impurities, and then inoculated into the acclimatization enhancement zone of the first low-oxygen aerobic tank at an inoculation concentration of 4000 mg / L. After 24 hours of aeration to activate the sludge activity, ammonia-oxidizing bacteria were added (7 g / L loading). The dissolved oxygen concentration in both the acclimatization enhancement zone and the reaction zone was controlled at approximately 0.6 mg / L, with a hydraulic retention time of 3.5 hours, resulting in a stable sludge concentration of approximately 4000 mg / L. The effluent nitrite concentration was continuously monitored. On day 18, the cumulative nitrite rate reached 62% and remained stable for 3 consecutive days, completing the short-cut nitrification acclimatization. After acclimatization, the wastewater entered the reaction zone for short-cut nitrification, generating nitrite while simultaneously removing some organic matter.

[0040] Step 4: Short-cut denitrification and phosphorus release; the wastewater after the reaction in the first low-oxygen aerobic tank enters the anoxic tank and is mixed with the 24% wastewater diverted from it. The anoxic tank is filled with a modified corn stalk-activated carbon composite slow-release carbon source carrier (filling amount 20%, particle size 7mm), the hydraulic retention time is controlled at 4.5h, the sludge concentration is about 4000mg / L, the dissolved oxygen concentration is below 0.3mg / L, the stirring device is continuously running, and the microorganisms carry out short-cut denitrification reaction and phosphorus release process by polyphosphate-accumulating bacteria.

[0041] Step 5: Phosphorus uptake and deep removal of organic matter; the wastewater after the reaction in the anoxic tank enters the second aerobic tank, where the dissolved oxygen concentration is controlled at 1.8-2.0 mg / L, the hydraulic retention time is 3.5 h, and the sludge concentration is about 4000 mg / L. The variable frequency blower automatically adjusts the aeration rate according to the dissolved oxygen data, and the pulse aeration pipe aeration frequency is 45 seconds / time. The microorganisms complete the deep removal of organic matter and the phosphorus uptake process by polyphosphate-accumulating bacteria.

[0042] Step 6: Solid-liquid separation and sludge recycling; Wastewater enters the sedimentation tank, and after solid-liquid separation, the supernatant enters the deep treatment unit; The sludge return ratio is controlled at 85%, and the sludge is returned to the acclimatization and enhancement zone of the first low-oxygen aerobic tank through the sludge return pump. The remaining sludge is discharged once every 1.5 days.

[0043] Step 7: Advanced treatment and compliant discharge; the supernatant is treated by an ultrafiltration membrane module (operating pressure 0.2 MPa, membrane flux 15 L / (m³)). 2 •h), backwash cycle 45min, backwash time 8min), followed by ultraviolet disinfection (disinfection dose 22mJ / cm²). 2 After treatment, the average concentration of COD in the effluent was 22.3 mg / L, the average concentration of NH3-N was 0.17 mg / L, the average concentration of TN was 7.8 mg / L, and the average concentration of TP was 0.79 mg / L, which met the Class IV discharge standard for wastewater treatment plants. The aeration energy consumption was reduced by 25% compared with the original SLOAO process. Example 2

[0044] This embodiment uses the ISLOAO process device and method described in this application to treat low carbon-to-nitrogen ratio wastewater from a food processing enterprise. The specific steps are as follows: Step 1: Pretreatment and water quality control; After impurities are removed by a screen (0.6mm aperture), the wastewater enters the equalization tank, where it remains for 7 hours. The intelligent control unit controls the pH adjustment device to adjust the pH value of the wastewater to about 7.2, the temperature adjustment device stabilizes the temperature at 20-23℃, the stirring device continuously stirs, and the online water quality monitoring instrument collects the influent parameters in real time: COD 280-410mg / L, NH3-N 41-53mg / L, TN 50-60mg / L, TP 5.0-6.2mg / L, and C / N ratio 2.4-3.2.

[0045] Step 2: Intelligent diversion ratio calculation and control; The preset effluent TN discharge standard is 10mg / L. The intelligent control unit calculates the influent diversion ratio r as 0.78~0.85 based on the influent parameters, and takes the average diversion ratio of 0.81. The sewage is transported to the first low-oxygen aerobic tank and the anoxic tank respectively through the intelligent diversion valve at a ratio of 81% and 19%. The diversion ratio is recalculated every 1 hour, and the opening of the diversion valve is dynamically adjusted.

[0046] Step 3: Short-cut nitrification acclimatization and reaction; Activated sludge from the traditional process was inoculated into the acclimatization enhancement zone of the first low-oxygen aerobic tank at an inoculation concentration of 4200 mg / L. After 24 hours of aeration to activate the sludge activity, ammonia-oxidizing bacteria were added (8 g / L loading). The dissolved oxygen concentration in both the acclimatization enhancement zone and the reaction zone was controlled at approximately 0.7 mg / L, with a hydraulic retention time of 4 hours, stabilizing the sludge concentration at approximately 4500 mg / L. The effluent nitrite concentration was continuously monitored. On day 16, the cumulative nitrite rate reached 65% and remained stable for 3 consecutive days, completing the short-cut nitrification acclimatization.

[0047] Step 4: Short-cut denitrification and phosphorus release; the wastewater after the reaction in the first low-oxygen aerobic tank enters the anoxic tank and is mixed with the diverted 19% wastewater. The anoxic tank is filled with a modified corn stalk-activated carbon composite slow-release carbon source carrier (filling amount 22%, particle size 8mm). The hydraulic retention time is controlled at 5h, the sludge concentration is about 4500mg / L, the dissolved oxygen concentration is below 0.4mg / L, and the stirring device is continuously running to complete the short-cut denitrification reaction and the phosphorus release process by polyphosphate-accumulating bacteria.

[0048] Step 5: Phosphorus uptake and deep removal of organic matter; the wastewater after the reaction in the anoxic tank enters the second aerobic tank, where the dissolved oxygen concentration is controlled at 1.9-2.1 mg / L, the hydraulic retention time is 4 hours, the sludge concentration is about 4500 mg / L, the aeration frequency of the pulse aeration pipe is 50 seconds / time, and the aeration volume is automatically adjusted by the variable frequency blower to complete the deep removal of organic matter and the phosphorus uptake process by polyphosphate-accumulating bacteria.

[0049] Step 6: Solid-liquid separation and sludge recycling; Wastewater enters the sedimentation tank, and after solid-liquid separation, the supernatant enters the deep treatment unit; The sludge return ratio is controlled at 90%, and the sludge is returned to the acclimatization and enhancement zone of the first low-oxygen aerobic tank through the sludge return pump. The remaining sludge is discharged once a day.

[0050] Step 7: Advanced treatment and compliant discharge; the supernatant is treated by an ultrafiltration membrane module (operating pressure 0.25 MPa, membrane flux 18 L / (m³)). 2 •h), backwash cycle 50min, backwash time 9min), followed by ultraviolet disinfection (disinfection dose 25mJ / cm²). 2 The treated effluent had an average COD concentration of 23.7 mg / L, an average NH3-N concentration of 0.23 mg / L, an average TN concentration of 9.9 mg / L, and an average TP concentration of 0.88 mg / L, meeting the Class A standard for urban wastewater treatment plants (GB18918-2002). The aeration energy consumption was reduced by 28% compared to the original SLOAO process, and no external carbon source was required, resulting in a significant reduction in treatment costs.

[0051] The average cumulative nitrite nitrogen rate in the effluent from the first low-oxygen aerobic tank was 66.5%, demonstrating the high efficiency and stability of the short-cut nitrification reaction. After 30 days of continuous operation, the concentrations of various pollutants in the effluent remained stable and met the standards, proving that the process applied for has good adaptability to industrial wastewater with low carbon-to-nitrogen ratios and overcomes the limitation of the narrow scope of application of the original patent.

[0052] This application provides an intelligent split-flow low-oxygen-aerobic-anoxic-aerobic (ISLOAO) process for treating low C / N ratio wastewater. Through structural innovation, intelligent control, and bio-enhancement, it overcomes many shortcomings of existing technologies, achieving efficient, energy-saving, and stable treatment of low C / N ratio wastewater, demonstrating significant technical advantages and application value. The core innovations of this application lie in the integration of intelligent split-flow control, segmented short-cut nitrification acclimatization, slow-release carbon source-enhanced denitrification, and deep treatment. These improvements work together to create a synergistic effect, significantly improving treatment efficiency, energy consumption, and applicability, surpassing existing patented technologies.

Claims

1. A device for treating low carbon-to-nitrogen ratio wastewater using a smart diversion-type multi-stage oxygen process, characterized in that: It includes a pretreatment unit, an intelligent diversion unit, a reaction unit, an advanced treatment unit, a sludge recycling unit, and an intelligent control unit connected in sequence; The pretreatment unit includes a bar screen, an equalization tank, and a water pretreatment module. The bar screen outlet is connected to the equalization tank. The equalization tank is equipped with a stirring device and an online water quality monitor (monitoring COD, NH3-N, TN, TP, and water temperature). The pretreatment unit is used to remove suspended solids and large particulate impurities from the wastewater and stabilize the influent water quality. The intelligent diversion unit includes a diversion pipe, an intelligent diversion valve, and a flow monitoring module. One end of the diversion pipe is connected to the outlet of the pretreatment unit, and the other end is connected to the first low-oxygen aerobic tank and the anoxic tank of the reaction unit, respectively. The intelligent diversion valve and the flow monitoring module are both electrically connected to the intelligent control unit and are used to dynamically adjust the influent diversion ratio r according to the influent water quality. The reaction unit includes a first low-oxygen aerobic tank, an anoxic tank, a second aerobic tank, and a sedimentation tank connected in sequence. The first low-oxygen aerobic tank is divided into a pre-acclimatization and enhancement zone and a post-reaction zone. The acclimatization and enhancement zone contains an ammonia-oxidizing bacteria inoculant carrier, and the reaction zone is equipped with a stirring device and a microporous aerator. The anoxic tank contains a slow-release carbon source carrier and a high-efficiency stirring device. The slow-release carbon source carrier is a modified corn straw-activated carbon composite carrier. The bottom of the second aerobic tank is equipped with a pulse aeration pipe connected to an external variable frequency blower; the bottom of the sedimentation tank is equipped with a sludge discharge port and a sludge return port, and the top is equipped with an effluent weir. The advanced treatment unit includes an ultrafiltration membrane module and a disinfection module. The effluent end of the sedimentation tank is connected to the ultrafiltration membrane module, and the outlet of the ultrafiltration membrane module is connected to the disinfection module to further remove suspended solids, microorganisms and residual pollutants from the water to ensure that the effluent meets the standards. The sludge recycling unit includes a sludge return pump and a sludge concentration monitor. One end of the sludge return pump is connected to the sludge return port at the bottom of the sedimentation tank, and the other end is connected to the acclimatization and enhancement zone of the first low-oxygen aerobic tank. The sludge concentration monitor is installed in the first low-oxygen aerobic tank and is electrically connected to the intelligent control unit to regulate the sludge return ratio. The intelligent control unit includes a controller, a data acquisition module, and a remote monitoring module. The data acquisition module is connected to the online monitoring instrument of each unit and is used to collect parameters such as water quality, flow rate, dissolved oxygen, and sludge concentration. The controller controls the operating parameters of the intelligent diversion valve, stirring device, blower, and sludge return pump based on the collected parameters. The dissolved oxygen concentration in the acclimatization enhancement zone and reaction zone of the first low-oxygen aerobic tank is controlled at 0.4-0.8 mg / L, and the dissolved oxygen concentration in the second aerobic tank is controlled at 1.6-2.2 mg / L. The first low-oxygen aerobic tank is inoculated with activated sludge and ammonia-oxidizing bacteria to achieve a short-cut nitrification acclimatization with a nitrite accumulation rate of 60% or more. The wastewater after the short-cut nitrification reaction is mixed with the wastewater transported to the anoxic tank by the intelligent diversion unit to complete the short-cut denitrification reaction and the phosphorus release process by polyphosphate-accumulating bacteria. Then, the wastewater undergoes phosphorus absorption and deep removal of organic matter in the second aerobic tank, solid-liquid separation in the sedimentation tank, and deep treatment to obtain water that meets the standards.

2. The apparatus according to claim 1, characterized in that: The water pretreatment module of the pretreatment unit includes a pH adjustment device and a temperature adjustment device. The pH adjustment device is used to adjust the pH value of the wastewater to 7.0 to 8.0, and the temperature adjustment device is used to stabilize the wastewater temperature at 18 to 28°C. Both are electrically connected to the intelligent control unit.

3. The apparatus according to claim 1, characterized in that: A guide plate is installed between the acclimatization and enhancement zone and the reaction zone of the first low-oxygen aerobic tank. The guide plate has evenly distributed guide holes to ensure that the sewage flows slowly and reacts fully. The ammonia-oxidizing bacteria carrier in the acclimatization and enhancement zone is a porous ceramic carrier with a bacterial agent loading of 5-8 g / L.

4. The apparatus according to claim 1, characterized in that: The slow-release carbon source carrier filling amount of the anoxic tank is 15% to 25% of the effective volume of the anoxic tank, the carrier particle size is 5 to 10 mm, the slow release cycle is 30 to 60 days, and it can be replenished or replaced regularly; the high-efficiency stirring device is a submersible double impeller stirrer to ensure uniform release of carbon source and full contact between sewage and microorganisms.

5. The apparatus according to claim 1, characterized in that: The pulse aeration pipes in the second aerobic tank are arranged in a ring, with an aeration frequency of 30-60 seconds per cycle. The variable frequency blower can automatically adjust the aeration volume according to the dissolved oxygen concentration in the second aerobic tank. The dissolved oxygen concentration is monitored in real time by an online dissolved oxygen meter and linked with the intelligent control unit.

6. The apparatus according to claim 1, characterized in that: The sludge return ratio of the sludge recycling unit is controlled at 60% to 100%. The sludge concentration monitor monitors the sludge concentration in the first low-oxygen aerobic tank in real time. When the sludge concentration is below 3000 mg / L or above 5000 mg / L, the intelligent control unit adjusts the speed of the sludge return pump to ensure that the sludge concentration is stable at 3000 to 5000 mg / L. The sludge discharge port at the bottom of the sedimentation tank regularly discharges the remaining sludge, with a discharge frequency of 1 to 2 times per day.

7. A method for treating low carbon-to-nitrogen ratio wastewater using an intelligent diversion multi-stage oxygen process, characterized in that, Wastewater treatment using the apparatus according to any one of claims 1 to 6 specifically includes the following steps: Step 1: Pretreatment and water quality control; After large particulate suspended solids and impurities are removed by the screen, the urban low carbon-to-nitrogen ratio wastewater enters the equalization tank. The pH value of the wastewater is adjusted to 7.0-8.0 and the temperature is stabilized at 18-28℃ by the pH adjustment device and the temperature adjustment device. The stirring device continuously stirs to ensure uniform water quality. The online water quality monitoring instrument collects parameters such as COD, NH3-N, TN, and TP of the influent in real time and transmits them to the intelligent control unit. Step 2: Intelligent diversion ratio calculation and control; The intelligent control unit dynamically calculates the influent diversion ratio r (the proportion of sewage entering the first low-oxygen aerobic tank to the total influent) based on the influent parameters collected in Step 1 and the preset effluent TN discharge standard, and then delivers the sewage to the first low-oxygen aerobic tank and the anoxic tank respectively through the intelligent diversion valve. Step 3: Short-cut nitrification acclimatization and reaction; Activated sludge is inoculated into the acclimatization and enhancement zone of the first low-oxygen aerobic tank, and ammonia-oxidizing bacteria are added. The dissolved oxygen concentration in the acclimatization and enhancement zone and the reaction zone is controlled at 0.4-0.8 mg / L, the hydraulic retention time is 2.5-4.5 h, and the sludge concentration is stabilized at 3000-5000 mg / L. The short-cut nitrifying bacteria community is enhanced through the bacteria carrier in the acclimatization and enhancement zone, so that the cumulative rate of nitrite nitrogen in the wastewater reaches 60% or more, thus completing the short-cut nitrification acclimatization; The acclimatized wastewater enters the reaction zone to continuously carry out the short-cut nitrification reaction, generating nitrite nitrogen, while removing some organic matter. Step 4: Short-cut denitrification and phosphorus release; the wastewater from the first low-oxygen aerobic tank enters the anoxic tank and mixes with another portion of wastewater directly transported to the anoxic tank by the intelligent diversion unit. The slow-release carbon source carrier in the anoxic tank slowly releases carbon source, and microorganisms use nitrite nitrogen generated from short-cut nitrification as electron acceptor and carbon source as electron donor to carry out short-cut denitrification reaction. At the same time, polyphosphate-accumulating bacteria complete the phosphorus release process. The hydraulic retention time in the anoxic tank is controlled at 3.5-5.5 hours, the sludge concentration is stabilized at 3000-5000 mg / L, and the stirring device is continuously running to ensure sufficient reaction. Step 5: Phosphorus uptake and deep removal of organic matter; the wastewater after the reaction in the anoxic tank is transported to the second aerobic tank. The intelligent control unit controls the operation of the variable frequency blower based on the online dissolved oxygen meter monitoring data. The dissolved oxygen concentration is adjusted to 1.6-2.2 mg / L through the pulse aeration pipe, the hydraulic retention time is controlled to be 2.5-4.5 h, and the sludge concentration is stabilized at 3000-5000 mg / L. The microorganisms complete the deep removal of organic matter and the phosphorus uptake process of polyphosphate-accumulating bacteria. Step 6: Solid-liquid separation and sludge recycling; the wastewater after the reaction in the second aerobic tank enters the sedimentation tank for solid-liquid separation, and the supernatant enters the deep treatment unit; part of the sludge is returned to the acclimatization and enhancement zone of the first low-oxygen aerobic tank through the sludge return pump. The sludge return ratio is dynamically adjusted by the intelligent control unit according to the sludge concentration monitoring data, and the other part is discharged periodically as surplus sludge. Step 7: Deep treatment and compliant discharge; The supernatant from the sedimentation tank is treated by an ultrafiltration membrane module to remove suspended solids, microorganisms and residual pollutants, and then disinfected by a disinfection module to meet the preset discharge standards, and can be directly discharged or reused.

8. The method according to claim 7, characterized in that: The formula for calculating the inlet flow ratio r in step 2 is as follows: In the formula: --The wastewater treatment plant complies with the TN discharge standard, mg / L; --Influent NH3-N concentration, mg / L; --Influent BOD5 concentration, mg / L; --Influent TN concentration, mg / L; --The organic matter removal rate of the first low-oxygen aerobic tank is calculated using the following formula: In the formula: --Design wastewater temperature, °C; --Design factor, with a value range of 1.0 to 1.2; --Combination coefficient, ranging from 0.15 to 0.25; --Saturation constant of ammonia nitrogen oxidized by ammonia-oxidizing bacteria, mg / L; --NH4 effluent from nitrification + -N concentration, mg / L; --Ammonia oxidizing bacteria attenuation coefficient, d -1 ; --Hydraulic retention time in the first low-oxygen aerobic tank, h; --Sludge concentration, mg / L; --MLVSS / MLSS, with a value range of 0.65 to 0.75; --Influent COD concentration, mg / L; The intelligent control unit collects inlet water parameters in real time, recalculates the diversion ratio r every 1 to 2 hours, and dynamically adjusts the opening of the intelligent diversion valve to ensure stable reaction efficiency.

9. The method according to claim 7, characterized in that: The specific process of short-cut nitrification acclimatization in step 3 is as follows: Take activated sludge from the traditional process and inoculate it into the acclimatization enhancement zone of the first low-oxygen aerobic tank at an inoculation concentration of 3500–4500 mg / L. Aerate for 24 hours to activate the sludge activity, add ammonia-oxidizing bacteria agent, control the dissolved oxygen concentration at 0.4–0.8 mg / L, and the hydraulic retention time at 2.5–4.5 hours. Continuously monitor the effluent nitrite concentration. When the cumulative nitrite rate is stable at 60% or above for 3 consecutive days, the short-cut nitrification acclimatization is completed. After acclimatization, ammonia-oxidizing bacteria agent can be added periodically every 7–10 days, with the addition amount being 5%–10% of the initial inoculation amount.

10. The method according to claim 7, characterized in that: The specific parameters for the deep treatment in step 7 are as follows: the operating pressure of the ultrafiltration membrane module is 0.1–0.3 MPa, and the membrane flux is 10–20 L / (m²). 2 •h), backwashing should be performed regularly, with a backwash cycle of 30–60 minutes and a backwash time of 5–10 minutes; the disinfection module uses ultraviolet disinfection with a disinfection dosage of 15–30 mJ / cm². 2 This ensures that the microbial indicators of the effluent meet the standards.

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