A system for wastewater quality assessment treatment

Abstract

The embodiment of the application provides a system for wastewater quality evaluation treatment, comprising: a reaction evaluation device and a wastewater treatment device; the reaction evaluation device comprises a plurality of reactors: a first reactor, which is placed in a first reaction group for reaction test, and the first reaction group is obtained by mixing activated sludge and experimental wastewater; a second reactor, which is placed in a second reaction group for reaction test, and the second reaction group is obtained by mixing activated sludge and pure water; and a third reactor, which is placed in a third reaction group for reaction test, and the third reaction group is experimental wastewater; and the wastewater treatment device comprises: an aeration stripping tank, which is used for aeration stripping treatment of actual wastewater when the third reaction group COD change trend indicates that the experimental wastewater contains volatile organic compounds; and a biological treatment unit, which is used for biological treatment of the actual wastewater after the aeration stripping treatment, or is used for direct biological treatment of the actual wastewater when the experimental wastewater does not contain volatile organic compounds. The system can improve the actual wastewater treatment effect.

Description

Technical Field

[0001] This application relates to the field of water treatment, specifically to a system for wastewater quality assessment and treatment. Background Technology

[0002] In wastewater treatment, COD (Chemical Oxygen Demand) is a core indicator for measuring the total amount of organic pollutants in wastewater and is widely used to assess the degree of wastewater pollution and treatment effectiveness. Determining the content of hard COD (recalcitrant COD) in wastewater through experimental methods can effectively evaluate the applicability and limitations of biological treatment processes. Specifically, if the proportion of hard COD in the wastewater is high, it indicates that biological methods are insufficient to achieve the removal standards, and advanced oxidation, adsorption, or other enhanced treatment methods need to be introduced. If the proportion of hard COD in the wastewater is low, biological treatment can be used as the primary process, offering high economic efficiency and sustainability.

[0003] Therefore, wastewater assessment tests with COD as the core are an important means of determining wastewater treatment strategies. However, with the increasing complexity of industrial wastewater types, it is difficult to fully reflect the treatment difficulty and actual needs of wastewater based solely on recalcitrant COD. It is also necessary to further distinguish the composition of COD. Therefore, how to provide a system for wastewater quality assessment and treatment that can distinguish other COD components in wastewater besides recalcitrant COD, provide support for actual wastewater treatment, and thus improve the wastewater treatment effect has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0004] In view of this, embodiments of this application provide a system for wastewater quality assessment and treatment, which can evaluate and distinguish other COD components in wastewater besides recalcitrant COD through a reaction assessment device, providing support for wastewater treatment devices to treat actual wastewater, thereby improving the treatment effect of actual wastewater.

[0005] To achieve the above objectives, the embodiments of this application provide the following technical solutions.

[0006] In a first aspect, embodiments of this application provide a system for wastewater quality assessment and treatment, comprising: a reaction assessment device and a wastewater treatment device;

[0007] The reaction evaluation device includes multiple reactors, comprising: a first reactor for placing a first reaction group and conducting reaction tests, wherein the first reaction group is obtained by mixing activated sludge and experimental wastewater; a second reactor for placing a second reaction group and conducting reaction tests, wherein the second reaction group is obtained by mixing activated sludge and pure water; and a third reactor for placing a third reaction group and conducting reaction tests, wherein the third reaction group consists only of experimental wastewater.

[0008] The wastewater treatment device includes:

[0009] The aeration stripping tank is used to perform aeration stripping treatment on actual wastewater when the experimental wastewater contains volatile organic compounds, as indicated by the COD change trend in the third reaction group.

[0010] The biological treatment unit connected to the aeration stripping tank is used for biological treatment of actual wastewater after aeration stripping treatment in the aeration stripping tank, or for direct biological treatment of actual wastewater when the COD trend of the third reaction group indicates that the experimental wastewater does not contain volatile organic compounds.

[0011] Optionally, the plurality of reactors further include:

[0012] The fourth reactor is used to place the fourth reaction group and conduct reaction experiments, which is obtained by adding a carbon source to the activated sludge.

[0013] Optionally, the reaction evaluation device further includes:

[0014] An air pump is used to extract gas.

[0015] The humidifier, connected to the air pump and each reactor, is used to adjust the humidity of the gas drawn by the air pump and then introduce the humidified gas into each reactor.

[0016] Optionally, the initial sludge concentration of the activated sludge in the first reactor, the second reactor, and the fourth reactor is 3000 mg / L, the initial COD of the first reactor and the third reactor is greater than or equal to 400 mg / L and less than or equal to 800 mg / L, the initial pH of each reactor is greater than or equal to 6.8 and less than or equal to 7.8, and the reaction test time is greater than or equal to 14 days and less than or equal to 21 days.

[0017] Optionally, the first, second, and fourth reactors are further supplemented with corresponding amounts of nitrogen and phosphorus, which are used as nutrients to maintain the activity of the activated sludge.

[0018] Optionally, the experimental wastewater is petroleum industry wastewater used in the experiment, while the actual wastewater is the actual petroleum industry wastewater to be biologically treated; the initial COD of the first and third reactors is 600 mg / L, the initial pH of each reactor is 7.2, and the reaction test lasts for 21 days.

[0019] Optionally, the experimental wastewater is industrial park wastewater used for the experiment, while the actual wastewater is actual industrial park wastewater to be biologically treated; the initial COD of the first and third reactors is 480 mg / L, the initial pH of each reactor is 7, and the reaction test lasts for 14 days.

[0020] Optionally, the first, second, third, and fourth reactors are further supplemented with deionized water to adjust the water level when the water level changes during the reaction experiment, so that the water level in any reactor is consistent.

[0021] Optionally, the aeration stripping tank includes:

[0022] The inlet is used to introduce actual wastewater into the aeration stripping tank.

[0023] An aeration device installed inside the aeration stripping tank is used to perform aeration stripping treatment on the actual wastewater.

[0024] The outlet, which is connected to the biological treatment unit, is used to introduce the actual wastewater that has undergone aeration and stripping treatment into the biological treatment unit.

[0025] Optionally, the wastewater treatment device further includes:

[0026] The advanced treatment unit, which is connected to the biological treatment unit, is used to further treat the actual wastewater that has undergone biological treatment by the biological treatment unit.

[0027] As can be seen, the system for wastewater quality assessment and treatment provided in this application includes a reaction assessment device and a wastewater treatment device. The reaction assessment device includes multiple reactors, which include: a first reactor for placing a first reaction group and conducting a reaction experiment, wherein the first reaction group is obtained by mixing activated sludge with experimental wastewater; a second reactor for placing a second reaction group and conducting a reaction experiment, wherein the second reaction group is obtained by mixing activated sludge with pure water; and a third reactor for placing a third reaction group and conducting a reaction experiment, wherein the third reaction group only includes experimental wastewater. The wastewater treatment device includes: an aeration stripping tank for performing aeration stripping treatment on actual wastewater (actual wastewater being the actual wastewater to be treated) when the COD trend of the third reaction group indicates that the experimental wastewater contains volatile organic compounds; and a biological treatment unit connected to the aeration stripping tank for performing biological treatment on the actual wastewater after aeration stripping treatment in the aeration stripping tank, or for directly performing biological treatment on the actual wastewater when the COD trend of the third reaction group indicates that the experimental wastewater does not contain volatile organic compounds. Therefore, the system for wastewater quality assessment and treatment provided in this application embodiment can first evaluate and distinguish other COD components in wastewater besides recalcitrant COD through a reaction assessment device, thereby providing support for wastewater treatment devices to treat actual wastewater and improving the treatment effect of actual wastewater. Attached Figure Description

[0028] 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 embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is an example diagram of an optional structure of the reaction evaluation device provided in the embodiments of this application;

[0030] Figure 2 This is an example diagram of an optional structure of the wastewater treatment device provided in the embodiments of this application;

[0031] Figure 3 This is a schematic diagram of an optional structure of the aeration stripping tank provided in the embodiments of this application. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] With increasingly stringent environmental standards, wastewater treatment plants need to accurately assess recalcitrant COD in order to optimize the selection of wastewater treatment processes. However, existing COD assessment methods (such as the dichromate method and spectrophotometry) can only reflect the total organic matter content, i.e., total COD, and cannot distinguish between biodegradable COD and recalcitrant COD. Secondly, existing assessment methods have single evaluation indicators. For example, the BOD5 (5-day biological oxygen demand) / COD ratio method can preliminarily determine biodegradability, but it does not consider the impact of the complexity of organic matter structure on the degradation pathway. For example, recalcitrant substances such as polycyclic aromatic hydrocarbons and halogenated compounds are metabolized slowly under aerobic conditions, and this method cannot quantify their residual amount. Existing testing devices do not consider the control of dynamic parameters such as temperature and dissolved oxygen (DO), affecting the realism of the degradation process simulation. At the same time, existing evaluation schemes cannot eliminate many interfering factors and cannot distinguish other COD components in wastewater besides recalcitrant COD. For example, COD from microbial metabolites (such as extracellular polymers) and volatile organic compounds can easily be misclassified as recalcitrant components (recalcitrant components are also known as recalcitrant COD). There is a lack of effective control group designs to determine whether such interference exists, that is, to distinguish other COD components in wastewater besides recalcitrant COD, so that appropriate processes can be selected to eliminate such interference in further wastewater treatment.

[0034] One method for assessing recalcitrant COD is as follows: Microorganisms fully degrade organic matter under aerobic conditions, and the soluble COD difference between the experimental group (wastewater) and the control group (pure water) is used to calculate the soluble recalcitrant COD in the wastewater. In actual experiments, activated sludge can be used. Activated sludge is a collective term for the microbial community and the organic and inorganic matter it adheres to. The specific measurement and assessment scheme is as follows: An experimental group is set up by mixing activated sludge with the wastewater to be tested and adjusting the volume to a final volume in a reaction vessel; a control group is set up by using pure water instead of wastewater, with other conditions consistent with the experimental group (e.g., the same amount and volume of activated sludge); degradation conditions include: temperature maintained at 22±3℃, pH adjusted to 6.8 to 7.8, and dissolved oxygen maintained at approximately 2 mg / L through aeration; the degradation time is typically set to 7 days, but the test time can be extended if the COD is not stable. During the measurement process, water samples can be centrifuged and filtered (e.g., using a 0.45 μm filter membrane), and the soluble COD can be analyzed using a Hach rapid COD analyzer.

[0035] In the aforementioned assessment scheme, the control group serves to eliminate the interference of activated sludge's own metabolic products (such as dissolved microbial products) on the results, which can improve the accuracy of the measurement to some extent. However, this scheme lacks a reasonable pretreatment plan for activated sludge, and the COD inherent in the activated sludge may still interfere with the results. Secondly, the control group uses pure water, which differs from actual wastewater in terms of ionic strength and inorganic salt composition, potentially affecting microbial metabolic activity and causing the control group's results to deviate from reality. Furthermore, this scheme does not include a control group to determine whether the wastewater contains volatile organic compounds. Therefore, existing assessment schemes for recalcitrant COD still cannot distinguish other COD components in wastewater besides recalcitrant COD (such as COD from volatile organic compounds in wastewater), and their accuracy needs improvement.

[0036] In view of this, embodiments of this application provide a system for wastewater quality assessment and treatment, which can evaluate and distinguish other COD components in wastewater besides recalcitrant COD through a reaction assessment device, providing support for wastewater treatment devices to treat actual wastewater (actual wastewater is the actual wastewater to be treated), thereby improving the treatment effect of actual wastewater.

[0037] The system for wastewater quality assessment and treatment provided in this application, with reference to the accompanying drawings, is described below. The system may include a reaction assessment device and a wastewater treatment device.

[0038] Figure 1 This is an example diagram of an optional structure of the reaction evaluation device provided in the embodiments of this application, such as... Figure 1 As shown, the reaction evaluation device may include multiple reactors, which may include: a first reactor A, for placing a first reaction group and conducting reaction tests, wherein the first reaction group is obtained by mixing activated sludge and experimental wastewater; a second reactor B, for placing a second reaction group and conducting reaction tests, wherein the second reaction group is obtained by mixing activated sludge and pure water; and a third reactor D, for placing a third reaction group and conducting reaction tests, wherein the third reaction group consists only of experimental wastewater.

[0039] Among them, the first reactor A, the second reactor B and the third reactor D are used to conduct reaction experiments on the first reaction group, the second reaction group and the third reaction group respectively under the same environmental variable conditions, and the COD of the first reaction group, the second reaction group and the third reaction group are periodically measured until the end time of the experiment is reached.

[0040] The periodic measurement trend of COD in the third reaction group can be used to determine whether the experimental wastewater contains volatile organic compounds (VOCs). If so, the actual wastewater is subjected to aeration stripping treatment before biological treatment to remove VOCs. If not, the actual wastewater is directly subjected to biological treatment. The COD of the first reaction group and the second reaction group measured at the end of the experiment are used to determine the recalcitrant COD of the experimental wastewater. The recalcitrant COD of the experimental wastewater is used to evaluate and select the advanced treatment method for the actual wastewater, which is performed after biological treatment.

[0041] Under aerobic conditions, microorganisms can use the organic pollutants in the experimental wastewater as a carbon source for metabolism, thereby removing the organic matter from the wastewater. After sufficient biological degradation, the remaining COD is recalcitrant COD, i.e., recalcitrant organic matter. This application embodiment designs a reaction evaluation device based on this measurement principle to measure and evaluate the recalcitrant COD in the experimental wastewater. The activated sludge is microorganism, and the experimental wastewater is the sampled wastewater from which the recalcitrant COD needs to be measured in this application embodiment.

[0042] In order to remove the interference of COD contained in the microorganisms (i.e., activated sludge) on the measurement results, the activated sludge needs to be pretreated before preparation. In the embodiments of this application, the activated sludge is obtained by washing and concentrating the raw sludge at least once. The washing and concentrating process may include: settling the raw sludge to obtain concentrated sludge; adding pure water to the concentrated sludge and mixing it evenly, then centrifuging and removing the supernatant solution.

[0043] Furthermore, after preparing the activated sludge and experimental wastewater, multiple reaction groups required for the evaluation experiment were prepared and placed in different reactors.

[0044] In a specific implementation, the first reactor A is used to put in the first reaction group and conduct reaction experiments. Specifically, the treated activated sludge and experimental wastewater can be put into the first reactor A to mix the activated sludge and the experimental wastewater to obtain the first reaction group.

[0045] The second reactor B is used to put in the second reaction group and conduct reaction experiments. Specifically, the treated activated sludge and pure water can be put into the second reactor B to mix the activated sludge and pure water to obtain the second reaction group.

[0046] The third reactor D is used to put in the third reaction group and conduct reaction experiments. Specifically, only experimental wastewater can be put into the third reactor, and the experimental wastewater can be used as the third reaction group.

[0047] In other words, the reaction evaluation device provided in this application embodiment is equipped with reactors corresponding to different reaction groups for conducting reaction experiments on different reaction groups.

[0048] In this embodiment of the application, the first reaction group in the first reactor A serves as the experimental group, used to determine the recalcitrant COD of the experimental wastewater; the second reaction group in the second reactor B serves as the blank group, used to determine the metabolic products of soluble microorganisms in the activated sludge; and the third reaction group in the third reactor D serves as the control group, used to determine the volatile organic compounds in the experimental wastewater.

[0049] Furthermore, in an optional implementation, in order to ensure the validity of the entire experiment and avoid experimental errors, a control group can be added to verify whether the entire reaction evaluation device is operating normally;

[0050] Based on this, refer to Figure 1 The reaction evaluation device may further include: a fourth reactor C, for placing a fourth reaction group and conducting reaction tests, wherein the fourth reaction group is obtained by adding a carbon source to activated sludge.

[0051] In the embodiments of this application, the fourth reaction group serves as a control group and can be used to verify whether the activated sludge can normally utilize carbon sources for metabolism to remove organic matter under the reaction evaluation device and environmental conditions. In turn, after sufficient biological degradation, the recalcitrant COD can be measured to verify the effectiveness of the entire experiment.

[0052] In an alternative embodiment, treated activated sludge and a carbon source (e.g., sodium benzoate) can be added to a fourth reactor C to mix and obtain the fourth reaction group.

[0053] In the embodiments of this application, the initial sludge concentration (MLSS) of the activated sludge in the first reactor A, the second reactor B, and the fourth reactor C can be 3000 mg / L, the initial COD of the first reactor A and the third reactor D can be greater than or equal to 400 mg / L and less than or equal to 800 mg / L, the initial pH of each reactor can be greater than or equal to 6.8 and less than or equal to 7.8, and the reaction test time can be greater than or equal to 14 days and less than or equal to 21 days.

[0054] In an optional embodiment, the initial COD of the first reactor and the third reactor may be, for example, 400 mg / L, 450 mg / L, 480 mg / L, 500 mg / L, 600 mg / L or 800 mg / L.

[0055] For example, when the initial COD in the reactor is 400 mg / L, the microbial state is relatively stable. If the initial COD in the reactor is too low (e.g., initial COD < 400 mg / L), it may lead to a decrease in the activity of the activated sludge. For another example, when the initial COD in the reactor is 800 mg / L, the activated sludge begins to enter a medium-to-high load state. If the initial COD is high (e.g., initial COD > 800 mg / L), it will lead to excessive organic load, rapid depletion of dissolved oxygen, and incomplete microbial metabolism. Therefore, in the embodiments of this application, the initial COD of the first reactor and the third reactor can be set to be greater than or equal to 400 mg / L and less than or equal to 800 mg / L.

[0056] In an alternative embodiment, the initial pH of each reactor may be, for example, 6.8, 7, 7.2, 7.4, or 7.8.

[0057] Regarding the initial pH in each reactor, for example, when the initial pH in the reactor is 6.8, the microorganisms can recover through their own alkalinity adjustment in a short time. If the pH is too low (e.g., pH < 6.8), it will inhibit the activity of the microorganisms, resulting in a decrease in COD removal rate. For another example, when the initial pH in the reactor is 7.8, it is not enough for the components in the experimental wastewater, such as ammonia nitrogen, to react completely. If the pH is too high (e.g., pH > 7.8), it will lead to chemical precipitation and interfere with the reaction process. Therefore, in the embodiments of this application, the initial pH of each reactor can be set to be greater than or equal to 6.8 and less than or equal to 7.8.

[0058] In an optional embodiment, the reaction test may last for, for example, 14 days, 17 days, or 21 days.

[0059] Regarding the reaction test time, if the reaction test time is too short (e.g., reaction test time < 14 days), the microorganisms have not yet adapted, which will lead to unstable test data, poor repeatability, and inability to assess long-term operation problems. If the reaction test time is too long (e.g., reaction test time > 21 days), it will lead to waste of resources and even introduce external contamination. Therefore, in this embodiment of the application, the reaction test time can be set to greater than or equal to 14 days and less than or equal to 21 days.

[0060] In practice, the initial COD of the first reactor A and the third reactor D, the initial pH of each reactor, and the specific reaction test time can be set according to the actual situation of the experimental wastewater and the test requirements.

[0061] In an optional embodiment, if the experimental wastewater is experimental petroleum industry wastewater and the actual wastewater is actual petroleum industry wastewater to be biologically treated, then the initial COD of the first reactor A and the third reactor D can be 600 mg / L, the initial pH of each reactor can be 7.2, and the reaction test can last for 21 days.

[0062] In another optional embodiment, if the experimental wastewater is industrial park wastewater used for the experiment, and the actual wastewater is actual industrial park wastewater to be biologically treated, then the initial COD of the first reactor A and the third reactor D can be 480 mg / L, the initial pH of each reactor can be 7, and the reaction test can last for 14 days.

[0063] In addition, in this embodiment of the application, in order to avoid the measurement results of the first reaction group, the second reaction group and the fourth reaction group deviating from the actual situation due to the reduced metabolic activity of microorganisms (i.e. activated sludge), it is necessary to supplement the nutrients required for the growth of activated sludge.

[0064] In an optional implementation, the first reactor A, the second reactor B, and the fourth reactor C are further supplemented with corresponding amounts of nitrogen and phosphorus, which are used as nutrients to maintain the activity of the activated sludge.

[0065] Specifically, the nitrogen and phosphorus contents can be obtained by measuring the Kjeldahl nitrogen and phosphate contents of the experimental wastewater and calculating them according to the ratio BOD / TKN-N / PO4-P = 100 / 5 / 1, where BOD is the BOD (chemical oxygen demand) content in the experimental wastewater, TKN-N is the Kjeldahl nitrogen content, and PO4-P is the phosphorus content. The nitrogen and phosphorus are used as nutrients to maintain the activity of the activated sludge, thereby avoiding the impact of reduced activated sludge metabolic activity on the measurement results.

[0066] Furthermore, continue to refer to Figure 1 The evaluation device may further include: an air pump F for extracting gas; and a humidifier E connected to the air pump F and each reactor for adjusting the humidity of the gas extracted by the air pump F and introducing the humidified gas into each reactor.

[0067] After preparing the required reaction groups for the experiment, each reactor was subjected to reaction experiments under the same environmental variable conditions. These environmental variables included temperature and pH. To ensure stable environmental conditions, pH was monitored after the experiment began, ensuring that the pH remained between 6.8 and 7.8. Sodium bicarbonate and hydrochloric acid could be used to adjust the pH. The temperature was controlled at 25±3℃. Meanwhile, to ensure the normal metabolism of microorganisms (i.e., activated sludge), dissolved oxygen (DO) concentration was monitored daily, ensuring it was greater than 2 mg / L. The MLSS concentration of activated sludge in reactors A, B, and C was measured every three days.

[0068] In addition, during the reaction experiment, attention should be paid to the water level in each reactor to ensure that the water level remains consistent at the beginning, during and at the end of the reaction. If the water level in any of the first reactor A, the second reactor B, the third reactor D and the fourth reactor C changes (for example, water evaporation causes the liquid level to drop), deionized water can be added to adjust the water level so that the water level in any reactor is consistent.

[0069] After the experiment begins, samples are periodically taken from each reactor and the dissolved COD is analyzed until the end of the experiment. In this embodiment, the sampling and measurement cycle can be daily, and the end of the experiment is from day 14 to day 21.

[0070] Furthermore, in the embodiments of this application, the fourth reactor C conducts a reaction experiment on the fourth reaction group under the same environmental variable conditions, and periodically (e.g., daily) measures the COD of the fourth reaction group until the end of the experiment. The COD of the fourth reaction group is used to verify whether the activated sludge reacts with the carbon source under the environmental variable conditions.

[0071] In a specific embodiment, if the COD of the fourth reaction group in the fourth reactor C, which is periodically measured, shows a decreasing trend during the reaction test, it indicates that under the environmental variable conditions, the activated sludge can react normally with the carbon source, and the entire test device is operating normally.

[0072] In this embodiment, at the end of the experiment, the COD measured in the first reaction group of the first reactor A is used as the baseline result for the preliminary determination of the recalcitrant COD in the experimental wastewater, and the COD measured in the second reaction group of the second reactor B is used as the control result. The baseline result may deviate from the actual recalcitrant COD in the experimental wastewater; that is, the baseline result may contain other COD components besides the actual recalcitrant COD, which may be misjudged as recalcitrant COD. This embodiment can distinguish other COD components besides recalcitrant COD in the wastewater through the second and third reaction groups, thereby providing support for the selection of actual wastewater treatment processes.

[0073] Specifically, the benchmark results may contain COD generated by activated sludge metabolism, i.e., the COD content corresponding to the control results. Therefore, the influence of activated sludge COD on recalcitrant COD can be eliminated through the control results. At the same time, the COD from volatile organic compounds contained in the experimental wastewater itself also affects the subsequent actual wastewater treatment effect. In this embodiment, the COD trend of the third reaction group in the third reactor D can be periodically measured to determine whether the experimental wastewater contains volatile organic compounds, and then determine whether the actual wastewater (the actual wastewater to be treated) corresponding to the experimental wastewater contains volatile organic compounds.

[0074] In an optional example, the reaction test can be divided into a continuous first time phase and a second time phase. The trend of COD change in the periodically measured third reaction group can be used to determine whether the experimental wastewater contains volatile organic compounds. For example, if in the first time phase, the COD of the periodically measured third reaction group decreases with time, and the decrease in each period accounts for more than 10% of the COD of the currently measured first reaction group, and in the second time phase, the change in COD of the third reaction group in each period accounts for less than or equal to 10% of the COD of the currently measured first reaction group, then it is determined that the experimental wastewater contains volatile organic compounds.

[0075] In other words, if, during the reaction test period, the COD content of the third reaction group, measured periodically, first undergoes a period of decline with a large change (i.e., a clear downward trend), and then undergoes a period of gradual decline with a small change in COD content, then it can be determined that the experimental wastewater contains volatile organic compounds.

[0076] If, during both the first and second time phases, the change in COD of the third reaction group in each cycle is less than or equal to 10% of the COD of the first reaction group being measured, then the experimental wastewater is determined to be free of volatile organic compounds. In other words, if the COD content of the third reaction group changes very little throughout the entire reaction test period, then the experimental wastewater is determined to be free of volatile organic compounds.

[0077] In this embodiment of the application, after determining that the experimental wastewater contains volatile organic compounds based on the COD change trend of the third reaction group, support can be provided for the wastewater treatment device to treat actual wastewater.

[0078] Figure 2 This is an example diagram of an optional structure of the wastewater treatment device provided in the embodiments of this application.

[0079] like Figure 2 As shown, the wastewater treatment device may include: an aeration stripping tank, used to perform aeration stripping treatment on the actual wastewater when the COD change trend of the third reaction group indicates that the experimental wastewater contains volatile organic compounds;

[0080] In addition, a biological treatment unit connected to the aeration stripping tank is used for biological treatment of the actual wastewater after aeration stripping treatment in the aeration stripping tank, or for direct biological treatment of the actual wastewater when the COD trend of the third reaction group indicates that the experimental wastewater does not contain volatile organic compounds.

[0081] In other words, if the reaction evaluation device determines that the experimental wastewater contains volatile organic compounds, the wastewater treatment device can set up an aeration stripping tank before the biological treatment unit to first perform aeration stripping treatment on the actual wastewater to remove the volatile organic compounds in the actual wastewater, thereby improving the effect of subsequent biological treatment of the actual wastewater.

[0082] Figure 3 This is a schematic diagram of an optional structure of the aeration stripping tank provided in the embodiments of this application, such as... Figure 3 As shown, the aeration stripping tank may include an inlet for introducing actual wastewater into the aeration stripping tank; an aeration device installed inside the aeration stripping tank for aeration stripping treatment of the actual wastewater; and an outlet connected to the biological treatment unit for introducing the aeration stripping treated actual wastewater into the biological treatment unit.

[0083] The outlet can be connected to a biological treatment unit via a connecting pipe, allowing the actual wastewater that has undergone aeration and stripping treatment to be fed into the biological treatment unit for biological treatment.

[0084] In an optional embodiment, the aeration stripping tank can be rectangular in shape, with the actual wastewater flowing horizontally within it. The design parameters of the aeration stripping tank include: a horizontal flow velocity of 0.1 m / s to 0.2 m / s, a hydraulic retention time of 5 min to 10 min, an effective water depth of 2 m to 3 m, a width-to-depth ratio of 1 to 1.5, and an aeration rate of 0.2 m³ / s per cubic meter of wastewater. 3 up to 0.4m 3 Air.

[0085] Continue to refer to Figure 2 In another alternative implementation, if the experimental wastewater does not contain volatile organic compounds, the actual wastewater can be directly biologically treated. That is, when setting up the wastewater treatment device, there is no need to set up an aeration stripping tank before the biological treatment unit. The actual wastewater can directly enter the biological treatment unit for biological treatment, such as using microorganisms to decompose organic pollutants in the wastewater.

[0086] Furthermore, in the embodiments of this application, the COD of the first reaction group and the COD of the second reaction group measured at the end of the experiment can be used to determine the recalcitrant COD of the experimental wastewater. Specifically, the recalcitrant COD of the experimental wastewater can be obtained by subtracting the COD of the second reaction group measured at the end of the experiment from the COD of the first reaction group measured at the end of the experiment; that is, the recalcitrant COD of the experimental wastewater is the COD of the experimental wastewater measured in the preliminary test minus the COD produced by the metabolism of activated sludge.

[0087] The recalcitrant COD of the experimental wastewater can be used to evaluate and select advanced treatment methods for actual wastewater. In specific implementation, the wastewater treatment may include a biological treatment stage and a further advanced treatment stage.

[0088] Continue to refer to Figure 3 The wastewater treatment device may further include: a deep treatment unit connected to the biological treatment unit, used for deep treatment of the actual wastewater that has undergone biological treatment by the biological treatment unit.

[0089] In this embodiment, the recalcitrant COD of the experimental wastewater can be compared with the emission standards to rationally select the subsequent advanced treatment method for the actual wastewater to achieve compliant discharge. For example, if the emission standard is 20 mg / L, and the recalcitrant COD of the experimental wastewater is greater than 20 mg / L, then further targeted advanced treatment of the actual wastewater is required. Advanced treatment methods may include ozone oxidation, biological filters, or activated carbon adsorption. If the recalcitrant COD of the experimental wastewater is less than 20 mg / L, then there is no need to design specific process units for the actual wastewater, and a simpler advanced treatment method can be used to achieve compliant discharge.

[0090] As can be seen, the system for wastewater quality assessment and treatment provided in this application includes a reaction assessment device and a wastewater treatment device. The reaction assessment device includes multiple reactors, which include: a first reactor for placing a first reaction group and conducting a reaction experiment, wherein the first reaction group is obtained by mixing activated sludge with experimental wastewater; a second reactor for placing a second reaction group and conducting a reaction experiment, wherein the second reaction group is obtained by mixing activated sludge with pure water; and a third reactor for placing a third reaction group and conducting a reaction experiment, wherein the third reaction group only includes experimental wastewater. The wastewater treatment device includes: an aeration stripping tank for performing aeration stripping treatment on actual wastewater (actual wastewater being the actual wastewater to be treated) when the COD trend of the third reaction group indicates that the experimental wastewater contains volatile organic compounds; and a biological treatment unit connected to the aeration stripping tank for performing biological treatment on the actual wastewater after aeration stripping treatment in the aeration stripping tank, or for directly performing biological treatment on the actual wastewater when the COD trend of the third reaction group indicates that the experimental wastewater does not contain volatile organic compounds. Therefore, the system for wastewater quality assessment and treatment provided in this application embodiment can first evaluate and distinguish other COD components in wastewater besides recalcitrant COD through a reaction assessment device, thereby providing support for wastewater treatment devices to treat actual wastewater and improving the treatment effect of actual wastewater.

[0091] The foregoing describes multiple embodiment schemes provided by the embodiments of this application. The optional methods described in each embodiment scheme can be combined and cross-referenced with each other without conflict, thereby extending to a variety of possible embodiment schemes. These can all be considered as the embodiment schemes disclosed and published by the embodiments of this application.

[0092] While the embodiments disclosed above are described in this application, this application is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A system for wastewater quality assessment and treatment, characterized in that, include: Reaction assessment device and wastewater treatment device; The reaction evaluation device includes multiple reactors, comprising: a first reactor for placing a first reaction group and conducting reaction tests, wherein the first reaction group is obtained by mixing activated sludge and experimental wastewater; a second reactor for placing a second reaction group and conducting reaction tests, wherein the second reaction group is obtained by mixing activated sludge and pure water; and a third reactor for placing a third reaction group and conducting reaction tests, wherein the third reaction group consists only of experimental wastewater. The wastewater treatment device includes: The aeration stripping tank is used to perform aeration stripping treatment on actual wastewater when the experimental wastewater contains volatile organic compounds, as indicated by the COD change trend in the third reaction group. The biological treatment unit connected to the aeration stripping tank is used for biological treatment of actual wastewater after aeration stripping treatment in the aeration stripping tank, or for direct biological treatment of actual wastewater when the COD trend of the third reaction group indicates that the experimental wastewater does not contain volatile organic compounds.

2. The system for wastewater quality assessment and treatment according to claim 1, characterized in that, The plurality of reactors also include: The fourth reactor is used to place the fourth reaction group and conduct reaction experiments, which is obtained by adding a carbon source to the activated sludge.

3. The system for wastewater quality assessment and treatment according to claim 2, characterized in that, The reaction evaluation device further includes: An air pump is used to extract gas. The humidifier, connected to the air pump and each reactor, is used to adjust the humidity of the gas drawn by the air pump and then introduce the humidified gas into each reactor.

4. The system for wastewater quality assessment and treatment according to claim 2, characterized in that, The initial sludge concentration of the activated sludge in the first, second, and fourth reactors is 3000 mg / L. The initial COD of the first and third reactors is greater than or equal to 400 mg / L and less than or equal to 800 mg / L. The initial pH of each reactor is greater than or equal to 6.8 and less than or equal to 7.

8. The reaction test time is greater than or equal to 14 days and less than or equal to 21 days.

5. The system for wastewater quality assessment and treatment according to claim 4, characterized in that, The first, second, and fourth reactors are also supplemented with corresponding amounts of nitrogen and phosphorus, which are used as nutrients to maintain the activity of the activated sludge.

6. The system for wastewater quality assessment and treatment according to claim 5, characterized in that, The experimental wastewater was petroleum industry wastewater used in the experiment, while the actual wastewater was actual petroleum industry wastewater to be biologically treated; the initial COD of the first and third reactors was 600 mg / L, the initial pH of each reactor was 7.2, and the reaction experiment lasted for 21 days.

7. The system for wastewater quality assessment and treatment according to claim 5, characterized in that, The experimental wastewater was industrial park wastewater used for the experiment, while the actual wastewater was actual industrial park wastewater to be biologically treated; the initial COD of the first and third reactors was 480 mg / L, the initial pH of each reactor was 7, and the reaction experiment lasted for 14 days.

8. The system for wastewater quality assessment and treatment according to claim 2, characterized in that, The first, second, third, and fourth reactors are also equipped with deionized water to adjust the water level when the water level changes during the reaction experiment, so that the water level in any reactor is consistent.

9. The system for wastewater quality assessment and treatment according to claim 1, characterized in that, The aeration stripping tank includes: The inlet is used to introduce actual wastewater into the aeration stripping tank. An aeration device installed inside the aeration stripping tank is used to perform aeration stripping treatment on the actual wastewater. The outlet, which is connected to the biological treatment unit, is used to introduce the actual wastewater that has undergone aeration and stripping treatment into the biological treatment unit.

10. The system for wastewater quality assessment and treatment according to claim 1, characterized in that, The wastewater treatment device also includes: The advanced treatment unit, which is connected to the biological treatment unit, is used to further treat the actual wastewater that has undergone biological treatment by the biological treatment unit.

Images