31 results about "Nitrite concentration" patented technology

The invention discloses a nitrite concentration monitoring method based on a sensor coupling soft measurement model. The method comprises the following steps: S1, acquiring target influence factor data; determining a plurality of target influence factors based on the water quality parameters and the nitrification process of the to-be-monitored sewage; s2, establishing a soft measurement model; the input of the soft measurement model is the target influence factor, and the output of the soft measurement model is the concentration of nitrite nitrogen; s3, determining the concentration of nitrite nitrogen; according to the method, the target influence factor is firstly acquired by utilizing the sensor, and the nitrite concentration is calculated or predicted in real time by utilizing the target influence factor, so that the problems that monitoring equipment is expensive, the monitoring range is small, the monitoring is inaccurate and the monitoring equipment cannot directly monitor the nitrite in the seriously polluted wastewater in the nitrite monitoring in the prior art can be solved.

The invention relates to the technical field of wastewater treatment or water quality purification, in particular to a method for synchronously culturing ammonia oxidizing bacteria and nitrite oxidizing bacteria, which comprises the following steps: selecting an inorganic material which is large in specific surface area and can quickly neutralize and release alkalinity as a nitrifying bacteria attachment carrier and an alkalinity supplement / pH regulator; the carrier is dissolved through nitration acid production, carbon dioxide and alkalinity are released, a carbon source and alkalinity required by growth are provided for nitrifying bacteria, and propagation of the nitrifying bacteria is promoted. Ammonia oxidizing bacteria and nitrite oxidizing bacteria are cultured synchronously by controlling the growth speed of the two bacteria in the culture process. By controlling the ammonia nitrogen concentration and nitrite concentration of the effluent at the end of culture to be lower than 50mg / L, sufficient time is provided for nitrite oxidizing bacteria to decompose an intermediate product nitrite, so that the purpose of simultaneously culturing AOB and NOB is achieved.

The invention discloses a continuous flow urban sewage granular sludge self-enrichment coupled autotrophic biological membrane deep nitrogen and phosphorus removal method, which comprises the following steps: inoculating a deep nitrogen and phosphorus removal device with floc whole-process nitrification sludge with the concentration of 2500-4500 mg / L, then filling sewage, enabling the floc whole-process nitrification sludge to be self-gathered into short-process nitrification granular sludge, starting sludge circulation, and carrying out secondary nitrification on the short-process nitrification granular sludge to obtain the short-process nitrification granular sludge. Sewage and granular sludge are mixed through an instantaneous mixing pipe and then enter a first mixing area, the nitrite accumulation amount is monitored, when short-cut nitrification is destroyed, an alkali liquor hydrazine composite NOB inhibitor is added into a second mixing area, the DO concentration of an aerobic area and the DO concentration of an anaerobic ammonia oxidation area are monitored and controlled, and the nitrite concentration is made to be lower than 0.8 mg / L. According to the method, short-cut nitrification of the granular sludge in the continuous flow urban sewage is realized, short-cut nitrification and denitrification of the granular sludge and deep nitrogen and phosphorus removal through coupling of anaerobic ammonia oxidation are realized, and the technical bottlenecks that the continuous flow granular sludge is difficult to culture, the short-cut nitrification granular sludge is difficult to realize, and the granular sludge and anaerobic ammonia oxidation coupled nitrogen removal is difficult to realize are broken through.

The present invention relates to the technical field of wastewater treatment, and in particular to a detection device and method for measuring anaerobic ammonium oxidation activity. The detection device comprises a reactor and a detector; the reactor comprises a first reaction chamber and a second reaction chamber; the first reaction chamber is used for an anaerobic ammonium oxidation reaction and a denitrification reaction of sludge to be tested; the second reaction chamber is used for a denitrification reaction of said sludge; and the detector is used for controlling and recording the flow rates of chemicals entering the first reaction chamber and the second reaction chamber, ensuring that the pH values of the first reaction chamber and the second reaction chamber are constant and the same. According to the device, the real-time activity and maximum activity of anaerobic ammonium oxidation can be obtained on the basis of the hydrogen ion consumption rate in the reaction process, avoiding the cumbersome process of continuously sampling and measuring the concentration of ammonia nitrogen or nitrite in a conventional method, and simplifying the operation process; the first reaction chamber and the second reaction chamber of the detection device use the same sludge as a control, and the interference caused by the denitrification process using endogenous organic matter as an electron donor is eliminated, improving the measurement precision.

The invention discloses a percolate treatment method based on a microalgae coupling nitration process, and belongs to the field of wastewater biological treatment and intelligent control, and the method comprises the following steps: constructing initial reaction conditions suitable for microalgae proliferation and nitration reaction; operating parameters such as ammonia nitrogen concentration, nitrite concentration, dissolved oxygen, temperature and microalgae concentration are collected to form real-time operating data; based on the weighted multi-parameter fitting relationship, calculating an optimal combination of the illumination intensity, the carbon source feeding rate, the cycle ratio and the reaction duration; when the ammonia nitrogen removal rate is continuously lower than a threshold value, calling historical data to carry out trend analysis, and dynamically correcting a fitting weight; applying the correction result to control the illumination condition and the water inlet and outlet proportion; after the operation cycle is finished, updating the fitting model by adopting an incremental learning mode to realize continuous optimization of the control strategy; according to the invention, the nitrogen element removal efficiency of the percolation liquid and the system stability are improved, and the self-adaptive adjustment capability is relatively strong.

A device and a method for maintaining the stability of anaerobic ammonium oxidation (anammox) by using a combined zeolite filler to resist water quality fluctuations are provided. The device includes a water inlet tank, an anammox reactor, and a water outlet tank, where the anammox reactor is filled with the combined zeolite filler maintained in a state of suspension, domestic sewage enters the anammox reactor through a water inlet pump, and effluent water enters the water outlet tank through an overflow port. The device combines the physical characteristics of zeolite adsorption of ammonium with the anammox process: when the concentration of ammonium in the influent water is too high, the zeolites will temporarily store the excess ammonium adsorbed; when the concentration of nitrite in the influent water is too high, the zeolites are capable to release the stored ammonium into a liquid phase through balanced adsorption desorption.

The invention discloses an intelligent fish tank monitoring method and device based on the Internet of Things, electronic equipment and a medium, and the method comprises the steps that water quality parameters of a fish tank are collected through a sensor group, and the water quality parameters comprise at least one of the temperature, the PH value, the dissolved oxygen concentration, the ammonia nitrogen content and the nitrite concentration; video data of a fish tank are collected through a camera, biological behavior characteristics of fishes are extracted through a computer vision algorithm, and the biological behavior characteristics comprise a swimming activeness index, a food taxis index, a respiratory rate index and posture anomaly detection; performing multi-modal data fusion on the water quality parameters and the biological behavior characteristics to generate a comprehensive evaluation result of the health state of the fish tank; and generating a control instruction according to the fish tank health state comprehensive evaluation result so as to control fish tank equipment to execute corresponding operation. According to the method, the water quality parameters and the fish biological behavior characteristics are synchronously obtained, the comprehensiveness of fish tank monitoring is improved, and more comprehensive and more accurate basic data support is provided for subsequent health assessment.

This invention relates to the field of wastewater biological treatment technology, specifically to a device and method for improving the autotrophic denitrification performance of a MABR reactor. It employs a composite membrane module combining a curtain-type silica gel filament membrane with excellent oxygen permeability with a spatial three-dimensional mesh packing material that facilitates the attachment of anaerobic ammonia-oxidizing bacteria, thereby coupling part of the nitrification reaction with the anaerobic ammonia oxidation reaction. Through the circulating reaction zone and membrane reaction zone within the reactor, nitrate nitrogen generated by anaerobic ammonia oxidation and excess nitrite nitrogen during instability adjustment are circulated and removed, thus improving the total nitrogen removal efficiency of the reactor. By adding appropriate amounts of sodium nitrite solution at appropriate times, the free nitrite concentration in the reactor mixture is increased. Simultaneously, the intermittent aeration ratio of the MABR is controlled to achieve synergistic inhibition of nitrite-oxidizing bacteria activity by low dissolved oxygen and high free nitrite, allowing the unstable short-range nitrification reaction to recover and improving the autotrophic denitrification performance of the reactor.

The application discloses a leachate treatment method based on a microalgae coupling nitrification process, belongs to the field of wastewater biological treatment and intelligent control, and constructs initial reaction conditions suitable for microalgae proliferation and nitrification reaction; operation parameters such as ammonia nitrogen concentration, nitrite concentration, dissolved oxygen, temperature and microalgae concentration are collected to form real-time operation data; based on a weighted multi-parameter fitting relationship, the optimal combination of light intensity, carbon source addition rate, circulation ratio and reaction length is calculated; when the ammonia nitrogen removal rate is continuously lower than a threshold value, historical data are called to perform trend analysis, and the fitting weight is dynamically corrected; the correction result is applied to control light conditions and water inlet and outlet ratio; after the operation cycle ends, the fitting model is updated in an incremental learning mode, and continuous optimization of the control strategy is realized; the application improves nitrogen removal efficiency and system stability of the leachate and has strong self-adaptive adjustment capacity.

The present invention provides a method of controlling a wastewater treatment plant. The plant comprises at least one process tank and an aeration structure configured for aeration of the at least one process tank. The method comprises alternating steps of increasing aeration to the at least one process tank when a first event occurs, wherein the first event is one of when a first threshold value of a first tank parameter is reached and when a first predetermined time period has expired, and decreasing aeration to the at least one process tank when a second event occurs, wherein the second event is one of when a second threshold value of a second tank parameter is reached and when a second predetermined time period has expired. The first and second tank parameters are selected from a group consisting of nitrate concentration, nitrite concentration, and ammonium concentration determined in the water in the at least one process tank, and the steps of increasing aeration and decreasing aeration are carried out to reduce N2O emissions from the plant.

This invention discloses a denitrification system for high-concentration nitrogen-containing wastewater. The denitrification system includes a loading tank, an aeration pump, a reactor, and a real-time monitoring and control device. The loading tank is connected to the reactor and controlled by valves. The aeration pump controls the switching between nitrification and denitrification reactions. The reactor is filled with packing material adsorbing mycobacteria with preservation number CCTCC M20241347. The real-time monitoring and control device is used to detect the ammonia nitrogen concentration, nitrite concentration, and pH value of the reaction liquid in the reactor, and based on the detected ammonia nitrogen concentration, nitrite concentration, and pH value, controls the switching of the aeration pump to achieve the switching between nitrification and denitrification reactions. It also controls the opening and closing of the valves to control the addition of organic carbon sources, acids, or alkalis from the loading tank to the reactor. This invention also discloses a denitrification process for high-concentration nitrogen-containing wastewater, which can achieve efficient denitrification of high-concentration nitrogen-containing wastewater.

The invention provides a control method and system of a short-cut nitrification and anaerobic ammonia oxidation reactor and the reactor, and relates to the technical field of wastewater treatment.The method includes the steps that in the short-cut nitrification process, obtained load parameters and substrate concentration time sequences are used for fitting the nitrite concentration, and the reaction coefficient of the actual generation amount and the target generation amount is calculated; the method comprises the following steps: firstly taking nitrite as a gas pump to adjust the gas flow of the gas pump, then taking the generated nitrite as a substrate of anaerobic ammonia oxidation reaction, fitting the nitrogen concentration to obtain the actual generation amount of nitrogen, calculating the deviation value, then setting a dynamic deviation threshold value on a fitting curve of the nitrogen concentration, judging whether the deviation of the generation amount exceeds the standard or not, and finally, according to a feedback result, judging whether the generation amount exceeds the standard or not. A PID control formula is applied to adjust load operation parameters, and corresponding adjustment strategies are formulated for different reaction stages. According to the invention, dynamic optimization adjustment of the load operation parameters of the short-cut nitrification and anaerobic ammonia oxidation coupling reactor is realized through real-time monitoring and PID control.

The invention discloses a pH and nitrite dual-response fluorescent indicator. The pH and nitrite dual-response fluorescent indicator comprises apple pectin and histidine in a mass ratio of 20: 31. The pH and nitrite dual-response fluorescent indicator provided by the invention has the advantages that the preparation method is simple and rapid; the used raw materials are edible, green, environment-friendly and high in safety; the water solubility is good, and the stability is high; the double responsiveness of pH and nitrite is realized. The invention further provides a preparation method and application of the fluorescent indicator. The invention further claims a method for testing pH value and nitrite concentration by using the fluorescent indicator.

The invention relates to high-sensitivity nitrite detection test paper and a preparation method thereof.The test paper comprises a detection base layer, the detection base layer contains a nitrite ion reaction substrate, the nitrite ion reaction substrate is red after making contact with nitrite ions, different nitrite ion concentrations are distinguished through different color gradations of the color, and the nitrite ion concentration is different from that of the nitrite ion reaction substrate. The detection base layer is soaked in a feed liquid and then is dried to obtain the high-sensitivity nitrite detection test paper, the feed liquid contains a nitrite ion reaction substrate and a pH regulator, and the nitrite ion reaction substrate is selected from one or more of aniline, p-toluidine, aminonaphthalene and Klehu acid. Compared with the prior art, the method provided by the invention has the characteristics of accurate concentration indication and high sensitivity, and especially when the nitrite concentration is low, the color gradation of different concentrations is clear.

The invention discloses a composite bacillus preparation for degrading nitrite and application of the composite bacillus preparation, and belongs to the technical field of biology. The composite bacillus preparation provided by the invention comprises the following components: bacillus YHBLS-1 and bacillus licheniformis YHD2, the preservation number of the bacillus YHBLS-1 is CCTCC NO: M20251258, the preservation number of the bacillus licheniformis YHD2 is CCTCC NO: M 20251259, the two strains are respectively fermented to prepare bacterial powder of a single strain, then the bacterial powder is compounded to obtain the composite bacillus preparation, and the composite bacillus preparation can be used for preparing the composite bacillus preparation. Compared with a single strain, the composite bacillus preparation can efficiently degrade nitrite and is remarkable in effect, the concentration of the nitrite in the sewage is reduced to 0.15 mg / L from 2.12 mg / L before putting within 48 hours when the composite bacillus preparation is put into aquaculture sewage with the adding amount of 5g / m < 3 >, the effect is remarkable, and the nitrite can be effectively degraded. The method is of great significance to purification and improvement of nitrite pollution in an aquaculture water environment, and has an application prospect.

The invention relates to the technical field of environmental microorganisms, in particular to Rhodococcus ruber CPU-RR2502 with a strong nitrite degradation function, the strain is preserved in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms, and the preservation number is CGMCC No.35890. The invention further discloses a preparation method of the Rhodococcus ruber CPU-RR2502 with the strong nitrite degradation function. The strain is separated from bottom mud of an aquaculture pond and has efficient degradation capacity on nitrite in a water body, and the degradation rate on 1g / L sodium nitrite within 72 hours reaches 96.8%. The strain can adapt to an aquaculture environment, can be used for developing a microbial preparation, greenly and safely controlling the nitrite concentration through a bioremediation mode, ensuring the safety of aquatic animals and reducing the risk of secondary pollution caused by a traditional chemical method, and has a wide application prospect.

The present invention provides a method for estimating nitrous acid concentration in an environment, comprising the following steps: S10: obtaining a nitric oxide concentration C1 and a nitrogen dioxide concentration C2, respectively; S20: detecting a nitrous acid concentration C3 in the same period as the nitric oxide concentration C1; S30: calculating a nitrogen oxide concentration generation rate A according to the formula A=C1 / C2; S40: establishing an inverse relationship between the nitrous acid concentration C3 in different time periods and the corresponding nitrogen oxide generation rate A; and S50: obtaining the nitric oxide concentration C1x and the nitrogen dioxide concentration C2x in the time period to be detected, and substituting them into the inverse relationship to calculate the nitrous acid concentration in the time period. The method for estimating nitrous acid concentration in an environment provided by the present invention directly infers the current nitrous acid concentration C3 after measuring the nitric oxide concentration C1 and the nitrogen dioxide concentration C2, thereby reducing monitoring costs.

The invention relates to a high-salt-resistant Android bacillus denitrificans, which is preserved in the China General Microbiological Culture Collection Center (CGMCC) on June 2, 2022, and the preservation number of the high-salt-resistant Android bacillus denitrificans is CGMCC No.25000. The high-salt-resistant Android bacillus denitrificans is a high-salt-resistant Android bacillus denitrificans strain. The antarcinia denitrificans provided by the invention has the beneficial effects that (1) the antarcinia denitrificans is good in salt tolerance, can resist the salinity of 10% at most, and has the optimal growth salinity of 5-8%; (2) the degradation effect on nitrate and nitrite is excellent, under the anoxic condition, the initial nitrate concentration is 340 ppm, the nitrate degradation rate reaches 99% in 72 h when the salinity is 5-10%, the initial nitrite concentration is 100 ppm, and the nitrite degradation rate reaches 97-98% in 72 h when the salinity is 5-10%.

The invention provides a construction method of a continuous flow short-cut denitrification biological membrane module with short hydraulic retention time and a construction treatment device based on the continuous flow short-cut denitrification biological membrane module, and relates to the technical field of biological sewage treatment. According to the construction method, short-cut denitrification floc sludge is quickly started in an SBR (sequencing batch reactor) by adopting anoxic starvation treatment, then biofilm culturing treatment is performed, and finally, a short-cut denitrification biofilm is put into a continuous flow reactor, so that the construction of the continuous flow short-cut denitrification biofilm module with short hydraulic retention time is realized. The construction time and the reaction time of the short-cut denitrification biological membrane module are greatly shortened, and meanwhile, the continuous flow treatment mode also solves the problems that the nitrite concentration is gradually reduced after reaching a peak value in one period in the periodic operation of the SBR reactor in short-cut denitrification, and the nitrite concentration is reduced along with the shortening of the reaction period. The problems of low nitrite accumulation rate, complex operation, difficult regulation and control and the like caused by gradually advanced occurrence time of a nitrite peak value are solved.

The invention relates to the technical field of chemical analysis and detection, in particular to a method for rapidly detecting mildew of tobacco leaves based on a nitrite colorimetric probe, which utilizes Ce-PCN-222 nano-enzyme to oxidize 2, 2 '-hydrazine-bis-3-ethylbenzothiazoline-6-sulfonic acid into green oxidized 2, 2'-diamine-bis-3-ethylbenzothiazoline-6-sulfonic acid, so that the mildew of the tobacco leaves can be rapidly detected. According to the property of 2, 2 '-hydrazine-bis-3-ethyl benzothiazoline-6-sulfonic acid and the sensitization effect of nitrite on Ce-PCN-222 nano-enzyme peroxidase oxidation system enzyme, the change of the nitrite concentration is caused based on the change of nitrate reductase caused by microorganisms in the tobacco leaf mildewing process; the method for rapidly detecting the mildew of the tobacco leaves by using the nitrite colorimetric probe is established. According to the method, the change rule of the nitrite content in the tobacco leaf mildewing process is proposed for the first time to predict tobacco leaf mildewing, a new nitrite colorimetric probe determination method is established by using Ce-PCN-222 nano-enzyme, the mildewed tobacco leaf recognition process is simple, rapid, accurate and easy to popularize, and economic losses caused by tobacco leaf mildewing can be effectively reduced.

The present invention relates to a method for detecting nitrite, belonging to the technical field of detection and analysis. The method is that under acidic conditions, 3,3'-dimethoxy-5,5'-dimethylbenzidine reacts with nitrite to change the color of the solution. Qualitative analysis can be carried out by the naked eye, or semi-quantitative analysis can be performed by comparing the reaction solution with a nitrite concentration colorimetric card, or quantitative analysis can be carried out by measuring the maximum absorbance of the reaction solution with a spectrophotometer. The chromogenic molecule used in the method of the present invention is 3,3'-dimethoxy-5,5'-dimethylbenzidine molecule, which is a TMB derivative, reducing the potential toxicity and carcinogenic and mutagenic risks during the detection process. At the same time, it has high specificity and sensitivity to nitrite, and the color development is stable, capable of meeting the detection requirements of a wide range of samples. In addition, the method of the present invention is simple to operate, and the reagents used are safe, easy to transport and store, and are suitable for home detection of food in daily life.

The invention provides a fresh-keeping device, a refrigeration appliance and a fresh-keeping control method.The fresh-keeping device is installed in a freezing chamber of the refrigeration appliance and comprises a fresh-keeping box with a box cover arranged on one side, a nitrite sensor installed in the fresh-keeping box and used for collecting the nitrite concentration, and a controller, and the first slow-release module can release slow-release substances into the preservation box from the air opening in the side surface of the preservation box to inhibit the generation of the nitrous acid amine. The independent food preservation box is arranged in the freezing chamber of the refrigeration appliance, generation of cancerogen N-nitrosamine is prevented from being affected by too high temperature of the refrigerating chamber or rotten acidic substances, in the environment with the relatively low freezing chamber, a nitrosamine inhibition mechanism is formed by combining release of natural extraction substances of the slow release module, and the food preservation effect is improved. And the safety of food storage is effectively improved.

The application provides a short-range nitrification and anaerobic ammonia oxidation reactor control method and system, and relates to the technical field of wastewater treatment.The application fits nitrite concentration by using obtained load parameters and substrate concentration time series in the short-range nitrification process, calculates the reaction coefficient of the actual generation amount and the target generation amount, adjusts the gas flow of the gas pump, uses the generated nitrite as the substrate of the anaerobic ammonia oxidation reaction, fits the nitrogen concentration, obtains the actual generation amount of nitrogen, calculates the deviation amount, sets a dynamic deviation threshold on the fitting curve of the nitrogen concentration, judges whether the generation amount deviation is over the standard, finally adjusts the load operation parameters according to the feedback result by using a PID control formula, and formulates corresponding adjustment strategies for different reaction stages.The application realizes the dynamic optimization and adjustment of the load operation parameters of the short-range nitrification and anaerobic ammonia oxidation coupled reactor by real-time monitoring and PID control.

The present application relates to the technical field of biological denitrification, and particularly relates to a SNADF efficient biological denitrification device and method based on endogenous biomass fermentation. The specific technical scheme is as follows: (1) in the reactor, sewage and livestock and poultry wastewater are added, after starting the short-cut nitrification process, the dissolved oxygen is controlled at 0.3-0.5 mg / L, the pH is 7.5-8.0, and the total nitrogen removal rate of the reactor is higher than 85%; (2) the C / N ratio is adjusted to 0-0.1, the temperature is adjusted to 20-25 DEG C, the HRT is adjusted to 48-60 h, and the starvation strategy time is 36-48 h; after the starvation strategy, the C / N ratio is restored to 1-1.5, the temperature is restored to 30-35 DEG C, the HRT is restored to 16-20 h, and the recovery period is 48-60 h; during the implementation of the starvation strategy, the ammonia nitrogen in the reactor effluent should not be higher than 50 mg / L, the nitrite concentration should not be higher than 20 mg / L, and the total nitrogen removal rate of the reactor is higher than 93%. The present application takes the endogenous biomass such as extracellular polymeric substance (EPS) as the fermentation substrate, realizes the SNADF process in the reactor, and can simultaneously realize high-level denitrification, sludge reduction performance and low-energy-consumption operation.

The present invention discloses a method for deep denitrification and phosphorus removal using continuous-flow municipal sewage granular sludge self-enrichment coupled with autotrophic biofilms. The method comprises: inoculating a deep denitrification and phosphorus removal device with flocculent, fully nitrifying sludge at a concentration of 2500 to 4500 mg / L, then filling it with sewage, causing the flocculent, fully nitrifying sludge to self-aggregate into short-cut nitrifying granular sludge, initiating sludge circulation, mixing the sewage and granular sludge in a transient mixing tube, and then entering a first mixing zone. The accumulated nitrite is monitored. When short-cut nitrification is disrupted, an alkali solution, ammonia, and a NOB inhibitor are added to the second mixing zone. The DO concentrations in the aerobic zone and the anaerobic ammonium oxidation zone are monitored and controlled to reduce the nitrite concentration to below 0.8 mg / L. This method achieves continuous-flow municipal sewage short-cut nitrification granular sludge, and achieves deep denitrification and phosphorus removal coupled with short-cut nitrification and denitrification of the granular sludge and anaerobic ammonium oxidation, overcoming the technical bottlenecks of difficult continuous-flow granular sludge cultivation, difficult implementation of short-cut nitrifying granular sludge, and difficult implementation of coupled denitrification of granular sludge and anaerobic ammonium oxidation.

The invention belongs to the technical field of gel preparation and nitrite detection, and particularly relates to hydrogel as well as a preparation method and application thereof. The invention develops a pretreatment-free colorimetric detection method for rapid determination of nitrite. A diazotization oxidation reaction of nitrite and TMB under an acidic condition enables the solution to generate color change from colorless to orange, and the color change process can be observed by naked eyes. And the absorbance value and the image gray value at 450nm can be used for quantitative detection. Based on the principle, hydrogel is introduced to construct the nitrite sensor. By utilizing the inherent three-dimensional grid structure of the hydrogel, macromolecules such as protein and fat compounds are blocked outside the gel and only can be retained on the surface layer of the gel; and nitrite permeates into the gel along with water to initiate a chromogenic reaction. The bottom image of the gel is collected through the smart phone, and the gray value of the gel is analyzed, so that the nitrite concentration can be quantified.

The invention discloses a method for detecting nitrite content based on a nitrogen-doped carbon quantum dot (N-CDs) fluorescent probe, which comprises the following steps: adding 2, 3-diaminopyridine and ultrapure water into polytetrafluoroethylene, uniformly mixing, sealing in a reaction kettle, reacting at 180 DEG C for 8 hours, cooling at room temperature, centrifuging in a centrifugal machine, and separating non-fluorescent sediments to obtain light brown supernate; separating insoluble solid particles from the supernate by using a microporous filter membrane, dialyzing the filtrate by using a dialysis bag, replacing a dialysis medium once every 6 hours, drying to obtain the nitrogen-doped carbon quantum dots, and determining the nitrite concentration in the sample solution containing nitrite to be detected by using a standard curve drawing method based on the nitrogen-doped carbon quantum dots. The N-CDs prepared by the invention shows a good application prospect in the aspect of rapid, efficient, high-selectivity and high-sensitivity detection of nitrite.

An absorption spectrum measurement method for simultaneously predicting concentrations of nitrate and nitrite in a water body comprises the following steps: firstly, collecting spectral data of single-component samples of nitrate and nitrite and a mixed sample of the single-component samples, and sequentially carrying out moving average filtering and normalization treatment; a BP neural network structure with two parallel channels is constructed, spectral features of nitrate and nitrite are extracted respectively, and respective concentration prediction is carried out; in the single-substance training stage, similar and heterogeneous sample pairs are constructed by using single-component samples, a differential learning mechanism is introduced, the distinguishing capability of the model on nitrate and nitrite characteristics is enhanced, and in the mixed substance fine tuning stage, part of a characteristic extraction layer is unfrozen, a regression layer is finely tuned, and interference information of mixed substances is learned; and inputting spectral data of a mixed solution of the nitrate and the nitrite into the trained model, and outputting concentration values of the nitrate and the nitrite. According to the method, under the condition that the spectrums of the two are seriously overlapped, simultaneous prediction can still be realized, and an accurate prediction result is obtained.

The present invention provides a water treatment device that can stably treat COD components while suppressing the generation of nitrite to a low level. [Solution] A water treatment apparatus comprising a biological treatment tank containing activated sludge containing bacteria capable of decomposing COD components, and into which water to be treated containing ammonia and thiocyanate ions is introduced. This water treatment apparatus comprises an aeration device that performs aeration in the biological treatment tank, and a measuring unit that measures at least one concentration value selected from the group consisting of ammonium concentration, nitrite concentration, and nitrate concentration in the treated water obtained by treating the water to be treated in the biological treatment tank. Furthermore, this water treatment apparatus comprises a control unit that adjusts the aeration airflow rate based on the difference between the ammonium concentration in the water to be treated and the ammonium concentration in the treated water measured by the measuring unit, and at least one index value selected from the group consisting of nitrite concentration, nitrate concentration, and the sum of nitrite concentration and nitrate concentration in the treated water measured by the measuring unit.

The invention discloses a denitrification system for high-concentration nitrogen-containing sewage. The denitrification system comprises a charging tank, an aeration pump, a reactor and a real-time detection control device, the charging tank is communicated with the reactor and is controlled by a valve; the aeration pump is used for controlling the conversion between nitration reaction and denitrification reaction; the reactor is filled with a filler which is adsorbed with mycobacteria with the preservation number of CCTCC (China Center for Type Culture Collection) M20241347; the real-time detection control device is used for detecting the ammonia nitrogen concentration, the nitrite concentration and the pH value of reaction liquid in the reactor, and controlling the aeration pump to be turned on and turned off on the basis of the detected ammonia nitrogen concentration, the detected nitrite concentration and the detected pH value of the reaction liquid in the reactor so as to realize conversion between nitration reaction and denitrification reaction; and controlling the opening and closing of the valve so as to control the addition of the organic carbon source, the acid or the alkali in the charging tank to the reactor. The invention further discloses a denitrification process of the high-concentration nitrogen-containing sewage, and efficient denitrification of the high-concentration nitrogen-containing sewage can be realized.