Evaluation Methods for Chemical Dosing Strategies in Wastewater Pipeline Networks

Abstract

This invention relates to an evaluation method for reagent dosing strategies in wastewater pipe networks, belonging to the field of wastewater treatment technology. It evaluates the effects of different dosing methods on odor and corrosion control in wastewater pipe networks, assesses contributions to greenhouse gas emission reduction and efficiency improvement in wastewater pipe networks, and evaluates the ecotoxicity to downstream wastewater treatment plants. The evaluation method includes: constructing a simulation system of an actual wastewater pipe network; the culture environment and biochemical properties of the simulation system used for testing the product are similar to those of the actual pipe network; the simulation system includes a pipe network reactor and S::CAN sensors, N2O sensors, CH4 sensors, and an odor monitoring system; adding the test product to an experimental line on the simulation system and evaluating the reagent dosing strategy by comparing the experimental line with a control line. This invention can evaluate the comprehensive performance of reagents and the effects of different dosing methods, providing performance assurance and potential problem prevention before the product is widely applied in practice.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to an evaluation method for chemical dosing strategies in wastewater pipe networks. Background Technology

[0002] Domestic and industrial wastewater is collected and transported by sewage pipe networks before entering wastewater treatment plants. During long-distance transportation, the wastewater undergoes many complex biochemical reactions under anaerobic conditions within the pipe networks, leading to several environmental risks. Currently, the most serious and concerning issues are odor, pipe corrosion, and the emission of the greenhouse gas methane (CH4). Odor is caused by the transformation of sulfur in wastewater. On one hand, sulfates in wastewater are reduced to sulfides by sulfate-reducing bacteria, releasing hydrogen sulfide (H2S) into the environment at pumping stations, wet wells, and other locations. On the other hand, organic sulfides in wastewater are converted into volatile organic sulfur compounds (VOSCs) through biological reduction, hydrolysis, and methylation, and released into the environment. Both H2S and VOSCs have unpleasant odors, causing foul odor nuisance. Pipe corrosion occurs because some of the generated H2S is absorbed (adsorbed) onto the moisture layer of the concrete pipe walls, where it is oxidized to sulfuric acid (H2SO4). The sulfuric acid reacts with the concrete pipes, causing them to crack. After anaerobic fermentation occurs in the sewage pipe network, methanogenic bacteria can use the products of anaerobic fermentation to produce methane. Methane is a potential greenhouse gas with a very low explosion limit. It not only causes environmental problems related to greenhouse gas emissions but also poses safety hazards. In addition, there is a risk of producing the greenhouse gas nitrous oxide (N2O), especially after nitrogen-containing agents are added to control odor and corrosion problems. Therefore, to address these issues, numerous biological and chemical products have been developed, employing various dosing methods to control the generation and release of sulfides and methane in sewage networks. For example, continuous dosing of oxidizing agents such as nitrates and air (or oxygen), or one-time dosing of biocidal agents such as ferrates, free nitrites (FNA), and polyoxometalates (POMs), can effectively reduce the content of sulfides and methane in sewage networks. However, these methods are currently rarely applied in practice, but practical application is inevitable. In reality, sewage networks are not independent systems but are connected to downstream sewage treatment plants, making the effects of chemical application more complex. Therefore, to avoid problems in practical applications, it is essential to test the dosing strategy of biological and chemical products before their use, including their comprehensive performance and dosing methods. Besides assessing the effectiveness in controlling odor, corrosion, and greenhouse gases in sewage networks, the assessment of downstream quality improvement and efficiency enhancement, as well as ecotoxicity, is also crucial.

[0003] Therefore, how to provide an evaluation method for chemical dosing strategies in sewage pipe networks has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an evaluation method for chemical dosing strategies in sewage pipe networks. This method can evaluate the overall performance of the chemicals and the effects of different dosing methods, providing performance assurance and potential problem prevention before the product is widely used in practice. It can not only ensure that the applied chemical dosing strategy alleviates the problems in the sewage pipe network, but also evaluate the impact on the downstream of the pipe network after application, achieving a comprehensive measurement of the effect of the entire sewage treatment system, so as to determine whether the product can be widely used in practice.

[0005] To achieve the above objectives, the present invention provides a method for evaluating the dosing strategy of chemicals in sewage pipe networks.

[0006] The evaluation assesses the effectiveness of different dosing methods in controlling odor and corrosion in wastewater pipe networks, its contribution to greenhouse gas emission reduction and efficiency improvement in wastewater pipe networks, and its ecotoxicity to downstream wastewater treatment plants. The evaluation methods include the following procedures:

[0007] (1) A simulation system for the actual sewage pipe network was constructed. The culture environment and biochemical properties of the simulation system used to test the product were similar to those of the actual pipe network. The simulation system was divided into a control line and an experimental line. Both lines were equipped with a pipe network reactor and S::CAN sensor, N2O sensor, CH4 sensor and odor monitoring system that could detect the operating indicators in real time.

[0008] (2) The product to be tested is added to the experimental line on the simulation system and the drug addition strategy is evaluated by comparing the experimental line with the control line.

[0009] Furthermore, the control and experimental lines of the simulation system include at least two sequentially connected pipeline reactors, the physical parameters of which are similar to those of the actual pipeline network.

[0010] Furthermore, the odor monitoring system can continuously monitor ammonia and volatile sulfur compounds such as methanethiol, dimethyl sulfide, and dimethyl disulfide to evaluate the effectiveness of the test product in controlling odor gases; the N2O and CH4 sensors can monitor changes in N2O and CH4 concentrations in real time to evaluate the contribution of the test product to greenhouse gas emission reduction; and the S::CAN sensor can continuously measure H2O and CH4 concentrations. - H2S, based on corrosion algorithms to evaluate the effectiveness of test products in controlling concrete corrosion; S::CAN sensor can continuously measure COD, TSS, To assess the impact of the tested products on downstream quality and efficiency improvement, as well as their ecotoxicity.

[0011] Furthermore, the testing phase is divided into three stages: steady state, product addition, and recovery.

[0012] Furthermore, the testing phase is divided into two states: continuous online measurement and manual sampling analysis with paused operation.

[0013] Furthermore, the product can be added in the form of low dose at high frequency, medium dose at medium frequency, high dose at low frequency, or online automatic addition via an automatic control system.

[0014] Furthermore, the chemical indicators tested are obtained by direct online measurement of long-term continuous data from sensors on the simulation system, as well as discrete data obtained by manual sampling. The biological indicators tested are obtained by manual sampling and biological analysis, including the viability of microorganisms, enzyme activity related to microbial metabolism, and microbial population characteristics, in order to evaluate the effects of various chemical and biological products.

[0015] Furthermore, the pipeline reactor includes an SBR reactor or an AO reactor to assess the impact of test products added to the pipeline on subsequent biological wastewater treatment.

[0016] Furthermore, the data output from the simulated system's pipeline reactor after replacing it with actual on-site pipelines can be used to evaluate the effects of pilot-scale or actual applications, enabling a simple and rapid evaluation of reagent dosing strategies.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention proposes an evaluation method for chemical dosing strategies in sewage pipe networks. It can assess the overall performance of the chemicals and the effects of different dosing methods, providing performance assurance and potential problem prevention before the product is widely used in practice. It can ensure that the applied chemical dosing strategy alleviates the problems in the sewage pipe network, and also assess the impact on the downstream of the pipe network after application, so as to achieve a comprehensive measurement of the effect of the entire sewage treatment system, in order to determine whether the product and dosing strategy can be widely used in practice. Attached Figure Description

[0019] Figure 1 The process and apparatus diagram for evaluating the effects of dosing strategies on odor, corrosion, and greenhouse gas emission reduction in a simulation system.

[0020] Figure 2 The process and apparatus diagrams are used to evaluate the downstream efficiency improvement and ecotoxicity impacts of the dosing strategy in the simulation system.

[0021] Figure 3 The process and apparatus diagram for evaluating the odor, corrosion, and greenhouse gas emission reduction effects of the pilot-scale dosing strategy.

[0022] Figure 4 The process and apparatus diagrams are used to evaluate the downstream quality improvement, efficiency enhancement, and ecotoxicity impact of the pilot-scale dosing strategy.

[0023] Figure 5 This is a comparison chart of nitrate reduction rates in the SBR reactor after the addition of reagents.

[0024] Figure 6 This is a comparison chart of nitrite reduction rates in the SBR reactor after the addition of reagents.

[0025] In the figure:

[0026] 1-Wastewater storage tank, 2-Test product stock solution, 3-First pipeline reactor, 4-Second pipeline reactor, 5-Third pipeline reactor, 6-S::CAN sensor, 7-Odor monitoring system, 8-N2O sensor, 9-CH4 sensor, 10-First peristaltic pump, 11-Second peristaltic pump, 12-First dosing port, 13-First manual sampling port, 14-Second dosing port, 15-Second manual sampling port, 16-Third manual sampling port, 17-Automatic control system, 18-SBR reactor, 19-Third peristaltic pump, 20-Aeration pump, 21-Fourth manual sampling port, 22-Wastewater pipeline. Detailed Implementation

[0027] To achieve the above objectives and effects, the technical means and structure adopted by the present invention will be described in detail with reference to the accompanying drawings, focusing on the features and functions of the preferred embodiments of the present invention.

[0028] This invention provides a method for evaluating the dosing strategy of chemicals in sewage pipe networks.

[0029] The evaluation assesses the effectiveness of different dosing methods in controlling odor and corrosion in wastewater pipe networks, its contribution to greenhouse gas emission reduction and efficiency improvement in wastewater pipe networks, and its ecotoxicity to downstream wastewater treatment plants. The evaluation methods include the following procedures:

[0030] (1) A simulation system for the actual sewage pipe network was constructed. The culture environment and biochemical properties of the simulation system used to test the product were similar to those of the actual pipe network. The simulation system was divided into a control line and an experimental line. Both lines were equipped with a pipe network reactor and S::CAN sensor, N2O sensor, CH4 sensor and odor monitoring system that could detect the operating indicators in real time.

[0031] (2) The product to be tested is added to the experimental line on the simulation system and the drug addition strategy is evaluated by comparing the experimental line with the control line.

[0032] In this embodiment, the control line and experimental line of the simulation system include at least two pipeline reactors connected in sequence, and the physical parameters of the pipeline reactors are similar to those of the actual pipeline network.

[0033] In this embodiment, the odor monitoring system can continuously monitor ammonia and volatile sulfur compounds such as methanethiol, dimethyl sulfide, and dimethyl disulfide to evaluate the effectiveness of the test product in controlling odorous gases; the N2O and CH4 sensors can monitor changes in N2O and CH4 concentrations in real time to evaluate the contribution of the test product to greenhouse gas emission reduction; the S::CAN sensor can continuously measure H2O and CH4 concentrations. - H2S, based on corrosion algorithms to evaluate the effectiveness of test products in controlling concrete corrosion; S::CAN sensor can continuously measure COD, TSS, To assess the impact of the tested products on downstream quality and efficiency improvement, as well as their ecotoxicity.

[0034] In this embodiment, the testing phase is divided into three stages: steady state, product addition, and recovery.

[0035] In this embodiment, the testing phase is divided into two states: continuous online measurement and paused manual sampling analysis.

[0036] In this embodiment, the product is added in the form of low dose and high frequency, or medium dose and medium frequency, or high dose and low frequency, or automatically online through an automatic control system.

[0037] In this embodiment, the chemical indicators tested are obtained by direct online measurement of long-term continuous data by sensors on the simulation system, as well as discrete data obtained by manual sampling. The biological indicators tested are obtained by manual sampling and biological analysis, including the viability of microorganisms, enzyme activity related to microbial metabolism, and microbial population characteristics, so as to achieve the evaluation of the effects of various chemical and biological products.

[0038] In this embodiment, the pipeline reactor includes an SBR reactor or an AO reactor to assess the impact of the test product added to the pipeline on subsequent biological wastewater treatment.

[0039] In this embodiment, the data output by replacing the pipeline reactor of the simulation system with the actual pipeline on site can be used to evaluate the pilot-scale or actual application effect, so as to achieve a simple and rapid evaluation of the reagent dosing strategy.

[0040] refer to Figure 1 The simulation system includes a wastewater storage tank 1, a test product reserve liquid 2, a first pipeline reactor 3, a second pipeline reactor 4, a third pipeline reactor 5, an S::CAN sensor 6, an odor monitoring system 7, an N2O sensor 8, a CH4 sensor 9, a first peristaltic pump 10, a second peristaltic pump 11, a first dosing port 12, a first manual sampling port 13, a second dosing port 14, a second manual sampling port 15, a third manual sampling port 16, and an automatic control system 17.

[0041] Wastewater storage tank 1 is connected in sequence to first pipeline reactor 3, second pipeline reactor 4, and third pipeline reactor 5 via pipelines. A first peristaltic pump 10 and a first dosing port 12 are installed on the pipeline connecting wastewater storage tank 1 to first pipeline reactor 3. A first manual sampling port 13 is installed on the pipeline connecting first pipeline reactor 3 to second pipeline reactor 4. A second dosing port 14 is installed on the pipeline connecting second pipeline reactor 4 to third pipeline reactor 5. A third manual sampling port 16 is installed on the pipeline connecting third pipeline reactor 5 to S::CAN sensor 6. A second manual sampling port 15 is installed on the pipeline connecting third pipeline reactor 5 to odor monitoring system 7. The test product reserve liquid 2 is connected to the first dosing port 12 via second peristaltic pump 11. The test product reserve liquid 2 is also connected to the second dosing port 14 via second peristaltic pump 11. The second peristaltic pump 11 is electrically connected to automatic control system 17.

[0042] refer to Figure 2 The simulation system includes a wastewater storage tank 1, a test product reserve liquid 2, a first pipeline reactor 3, a second pipeline reactor 4, a third pipeline reactor 5, an S::CAN sensor 6, an odor monitoring system 7, an N2O sensor 8, a CH4 sensor 9, a first peristaltic pump 10, a second peristaltic pump 11, a first dosing port 12, a first manual sampling port 13, a second dosing port 14, a third manual sampling port 16, an automatic control system 17, an SBR reactor 18, a third peristaltic pump 19, an aeration pump 20, a fourth manual sampling port 21, and a wastewater pipeline 22.

[0043] Wastewater storage tank 1 is connected sequentially to first pipeline reactor 3, second pipeline reactor 4, and third pipeline reactor 5 via pipelines. A first peristaltic pump 10 and a first dosing port 12 are installed on the pipeline connecting wastewater storage tank 1 to first pipeline reactor 3. A first manual sampling port 13 is installed on the pipeline connecting first pipeline reactor 3 to second pipeline reactor 4. A second dosing port 14 is installed on the pipeline connecting second pipeline reactor 4 to third pipeline reactor 5. An SBR reactor 18 is installed between third pipeline reactor 5 and S::CAN sensor 6. A third manual sampling port 16 and a third peristaltic pump 19 are installed on the pipeline connecting the three-pipe reactor 5 and the SBR reactor 18. A fourth manual sampling port 21 is installed on the pipeline connecting the SBR reactor 18 and the S::CAN sensor 6. An aeration pump 20 is installed on the pipeline connected to the bottom of the SBR reactor 18. The test product stock solution 2 is connected to the first dosing port 12 through the second peristaltic pump 11. The test product stock solution 2 is also connected to the second dosing port 14 through the second peristaltic pump 11. The second peristaltic pump 11 is electrically connected to the automatic control system 17.

[0044] This invention proposes an evaluation method for chemical dosing strategies in wastewater pipe networks. A simulation system, similar in performance to an actual pipe network, is configured with sensors capable of continuously monitoring multiple indicators. The provided continuous operational data is compatible with long-term practical applications. The monitored data includes HS... - The concentrations of H2S, ammonia, and volatile sulfides such as methanethiol, dimethyl sulfide, and dimethyl disulfide were monitored to assess the effectiveness of the applied chemical dosing strategy in controlling odor problems. The corrosion algorithm based on concrete corrosion rate was used to assess the effectiveness in controlling pipeline corrosion. Data including N2O and CH4 were monitored to assess the contribution of the applied chemical dosing strategy to greenhouse gas emission reduction. Data including COD and TSS were monitored to assess the effect of the applied chemical dosing strategy on improving the quality and efficiency of downstream wastewater treatment plants.

[0045] This invention constructs a downstream treatment unit connected to a sewage pipe network. The tested effluent enters the downstream sewage unit, and the monitored data includes... To assess the ecotoxicity of the applied chemical dosing strategy to subsequent wastewater treatment.

[0046] This invention evaluates the effectiveness of chemical dosing strategies applied to sewage pipe networks. The developed biological and chemical products are designed to solve problems plaguing sewage pipe networks. Before practical application, the evaluation method of this invention provides performance assurance to prevent unforeseen problems during application. The technical methods proposed in this invention can accurately and continuously measure various indicators, and a single investment can be used for a long time. This invention can be used to test and evaluate any developed products and their application methods.

[0047] A method for evaluating biological and chemical product dosing strategies applied to wastewater pipe networks, specifically assessing the effectiveness of the applied product dosing strategies in reducing odor, corrosion, and greenhouse gas emissions in wastewater pipe networks, and constructing a system such as... Figure 1 The system shown collects the influent from the actual sewage pipeline in the sewage storage tank 1. The physical parameters of the first pipeline reactor 3, the second pipeline reactor 4, and the third pipeline reactor 5 are exactly the same, but it is not limited to three reactors. More reactors can be set up in series to simulate the actual long-distance pipeline. It has been verified that the biochemical environment formed is similar to the actual pipeline network, and the production of sulfides, methane, etc. is also similar to that of the actual pipeline network. Figure 1 For the experimental line, when the test product stock solution 2 is a liquid, it is added to the pipeline reactor by the second peristaltic pump 11. When it is a solid, it is added directly to the first dosing port 12 or the second dosing port 14. Since different products have different control mechanisms, they need to be applied at different locations in the pipeline. Therefore, multiple dosing ports are set up so that it can be added at the beginning or end of the pipeline. When the test product stock solution 2 is added online, the automatic control system 17 controls the start and stop of the pump to evaluate the effect of different dosing methods. The control line has the same composition as the experimental line, but no dosing is performed in operation.

[0048] Before testing the product under test, the control line and the experimental line run synchronously for 3-6 months or longer until the monitoring indicators in the S::CAN sensor 6 stabilize; this stage is the steady-state stage. When testing the product under test, the reagent is added at either the first dosing port 12 or the second dosing port 14 of the experimental line. The dosage, frequency, or automatic online dosing can be freely selected according to the characteristics of different products. The N2O sensor 8 and CH4 sensor 9 can monitor the changes in N2O and CH4 concentrations in real time, and monitoring is performed at both the beginning and end of the pipeline to evaluate the control effect of the reagent at different locations. The S::CAN sensor 6 monitors pH and HS-H+ in real time. - The odor monitoring system 7 monitors ammonia and volatile sulfur compounds such as methanethiol, dimethyl sulfide, and dimethyl disulfide in real time, including H2S, COD, and TSS. In addition to the online monitoring, gas samples are taken at the second manual sampling port 15, and liquid samples are taken at the third manual sampling port 16. The accuracy of the monitored chemical indicators is verified using analytical methods. When the added agent is a biological product, biological indicator analysis is performed, including but not limited to live and dead cell staining, flow cytometry analysis, and microbial community analysis. During the recovery phase after adding the test product, the dosing is stopped, and the online sensors continuously monitor the indicators. Based on the online monitoring data, manual sampling and analysis of important biological indicators can be selected.

[0049] This invention also provides an assessment of the effects of the applied product on downstream efficiency improvement of wastewater pipe networks and ecotoxicity of wastewater treatment units, constructing a system such as... Figure 2 The system shown has a sewage storage tank 1 that collects the influent from the actual sewage pipeline. The first pipeline reactor 3, the second pipeline reactor 4, and the third pipeline reactor 5 are connected in series. The effluent from the third pipeline reactor 5 enters the SBR reactor 18 through the third peristaltic pump 19. Alternatively, the SBR reactor can be replaced with an AO reactor. The effluent from the SBR reactor is controlled by the S::CAN sensor 6. Figure 2 The experimental line and the control line have the same composition, but no drugs are administered during operation.

[0050] Before testing the product under test, the control line and the experimental line should run synchronously for 3-6 months or longer until the monitoring indicators in the S::CAN sensor 6 stabilize; this stage is the steady-state stage. When testing the product under test, dosing is performed at either the first dosing port 12 or the second dosing port 14 of the experimental line, while no dosing is performed on the control line. The S::CAN sensor 6 can then monitor nitrite levels in real time. nitrates Concentration is used to assess the impact of the added product on the SBR reactor (or AO reactor). When the added agent is a biological product, the biotoxicity of the product to the SBR can be analyzed through the fourth manual sampling port 21, including but not limited to testing whether the abundance of bacteria such as NOB is affected. Dosing is stopped during the recovery phase of adding the test product, and online sensors continuously monitor indicators. Based on the online monitoring data, key biological indicators can be manually sampled and analyzed.

[0051] Example 1:

[0052] This embodiment provides a comprehensive performance evaluation method for chemical products used to control sulfides and methane in sewage pipe networks. Polyoxometalates (POMs) are a class of inorganic cluster compounds formed by oxygen linkages between former transition metal ions. They have a similar stereochemical structure to sulfates and are strong oxidants, thus proven to reduce the formation of sulfides and methane in sewage pipe networks. Before practical application, their various properties are evaluated using the method of this invention. In the first stage of the test (steady-state stage), water is drawn from an actual sewage pipe network into a 50L sewage storage tank 1. Water is then introduced into the first pipe network reactor 3 via a first peristaltic pump 10 for 5 minutes at 6-hour intervals, simulating the typical hydraulic retention time of sewage. The effluent from the first pipe network reactor 3 serves as the influent to the second pipe network reactor 4, and the effluent from the second pipe network reactor 4 serves as the influent to the third pipe network reactor 5. The effluent from the third pipe network reactor 5 enters the S::CAN sensor 6 for online monitoring of HS. - H2S, when HS - When the H2S time-concentration curve shows no significant fluctuations, the system reaches stable operation. At this point, the second stage of testing (product addition) begins. After a system influent, the test product stock solution 2 (polyoxometalate stock solution) is added to the starting point of the pipeline network through the second peristaltic pump 11 at the first dosing port 12 of experimental line A. Control line A remains unoperated. The purpose of the dosing is to control the generation of sulfides and methane at the end of the pipeline network. This is achieved through the H2S signal output by the S::CAN sensor 6. - The H2S numerical curve, by comparing the results of experimental line A and control line A, directly reveals the effect of POMs on sulfide control. The values ​​output by N2O sensor 8 and CH4 sensor 9 directly reveal the effect of POMs on the control of greenhouse gas CH4 and the impact on the release of greenhouse gas N2O. The odor monitoring system 7 directly reveals the effect of POMs on odor control. One hour after dosing, headspace gas samples and effluent samples are taken from the end of the pipeline network through the second manual sampling port 15 and the third manual sampling port 16, respectively. The concentrations of sulfides, methane, and volatile sulfides in the samples are analyzed using the methylene blue method and gas chromatography. The values ​​output by S::CAN sensor 6 at the same time are compared to ensure the accuracy of the online monitoring sensor results. Figure 2As shown, the same dosing operation was performed on another experimental line B, while no operation was performed on control line B. The effluent from the third pipeline reactor 5 entered the SBR reactor 18 through the third peristaltic pump 19. The SBR reactor was aerated by the aeration pump 20. The effluent from the SBR reactor entered the S::CAN sensor 6. By comparing the nitrite, nitrate, and COD concentration curves output by the S::CAN sensor 6 with the results of experimental line B and control line B, the effect of POMs on downstream wastewater denitrification can be obtained. The TSS concentration curve output by the S::CAN sensor 6 can be used to obtain the effect of POMs on whether downstream sludge volume reduction is achieved. A water sample of the SBR reactor effluent can be taken for analysis at the fourth manual sampling port 21, and the results are consistent with those of the online sensor. To assess the bactericidal properties and ecotoxicity of POM to downstream applications, biofilm (sediment) from the third pipeline reactor 5 was analyzed for live and dead cell staining, and microorganisms from the SBR reactor were analyzed for microbial community. After the product to be tested was added once, the system entered the third stage (recovery stage). During the recovery stage, the data output by the S::CAN sensor 6 was used to determine the end of a test cycle when the experimental line and the control line values ​​were equal and stable.

[0053] S::CAN sensor 6 displays the HS of experimental line A - The H2S concentration was significantly lower than control line A, and the pH value remained stable throughout. The volatile sulfur compound concentration in the odor monitoring system 7 of experimental line A was also significantly lower than control line A. The CH4 sensor 9 connected to reactors 3 and 5 in the first and third pipe networks was significantly lower than control line A. The N2O sensor 8 connected to reactors 3 and 5 in the first and third pipe networks showed similar values ​​to control line A. Manual sampling analysis proved that the product could destroy the extracellular polymers of microorganisms, inhibit the metabolism of sulfate-reducing bacteria and methanogens, thereby inhibiting the production of sulfides and methane. The S::CAN sensor 6 in experimental line B showed a COD concentration significantly higher than the control line, indicating that it helps improve downstream quality and efficiency. The S::CAN sensor 6 in experimental line B showed a nitrate concentration higher than control line B. After dosing, the nitrate reduction rate decreased; however, since POMs were added at the front end of the pipe network, under the dilution effect of the measured wastewater, such as... Figure 5 As shown, the nitrate reduction rate will actually increase, and in addition, as Figure 6 As shown, the nitrite concentration was below control line B, and the nitrite reduction rate increased after dosing. Therefore, the addition of this product to the sewage network did not have a negative impact on downstream wastewater denitrification. Thus, the evaluation results indicate that this tested product can solve the odor and corrosion problems of the sewage network, contribute to greenhouse gas emission reduction, help downstream wastewater treatment plants improve efficiency, and will not adversely affect subsequent wastewater denitrification.

[0054] In addition, multiple cycles of testing and evaluation can be performed on the product under test to ensure the stability of product performance.

[0055] Example 2:

[0056] In this embodiment, the comprehensive performance of a chemical product for oxidizing sulfides generated in sewage pipe networks was evaluated. This product does not inhibit the activity of sulfate-reducing bacteria but can stimulate sulfide oxidation, therefore... Figure 1 As shown, the first stage (steady-state stage) is the same as in Example 1. In the second stage (test stage), the test product stock solution 2 is added to experimental line A through the second dosing port 14. Sulfides have already been generated and accumulated in the first pipeline reactor 3 and the second pipeline reactor 4 at the front end of the pipeline network. The effect of the product on sulfide oxidation is evaluated by adding it at the end. The test product stock solution is added once through the second peristaltic pump 11 each time water is added. The addition is carried out over a long period of time, and the S::CAN sensor 6 continuously monitors and outputs continuously measured data.

[0057] S::CAN sensor 6 displays the HS of experimental line A - The H2S concentration was significantly lower than control line A. The volatile sulfur compound concentration in the odor monitoring system 7 of experimental line A was also significantly lower than control line A. The CH4 sensor 9 connected to the third pipeline reactor 5 showed a value significantly lower than control line A. Although the test product contained nitrogen, the dosage was low. The N2O sensor 8 connected to the third pipeline reactor 5 in experimental line A showed a value similar to control line A. The S::CAN sensor 6 in experimental line B showed a COD concentration significantly lower than the control line, while the nitrite concentration was significantly higher than the control line. Therefore, the evaluation results indicate that the test product can reduce the concentration of sulfides at the end of the pipeline network, thereby controlling odor and corrosion in the sewage pipeline network. It can reduce the release of greenhouse gas CH4 without increasing the release of greenhouse gas N2O, which is detrimental to downstream quality improvement and efficiency enhancement and increases the load on sewage denitrification.

[0058] Example 3:

[0059] In this embodiment, the comprehensive performance of a biological product for controlling the generation of sulfides and methane in a sewage pipe network was evaluated. According to the manufacturer, this biological product slows down the metabolism and reproduction of anaerobic bacteria, disrupts the biofilm, and then the biofilm flows away from the pipe with the flowing sewage. Therefore, as... Figure 1 As shown, the first stage (steady-state stage) is the same as in Example 1. In the second stage (test stage), the test product stock solution 2 is added to the experimental line A through the first dosing port 12. Damaging the biofilm at the front end of the pipeline can reduce the accumulation of sulfides and methane in the pipeline.

[0060] S::CAN sensor 6 displays the HS of experimental line A -The H2S concentration was not significantly different from the control line A. The concentrations of volatile sulfur compounds, N2O, and CH4 in the odor monitoring system 7, N2O sensor 8, and CH4 sensor 9 in experimental line A were also similar to those in control line A. The TSS concentration in the S::CAN sensor 6 was also not significantly different between experimental line A and control line A. This indicates that the biological product is ineffective in controlling odor and corrosion problems in sewage pipe networks and has no significant effect on greenhouse gas emission reduction. Field trials or practical applications are not recommended.

[0061] Example 4:

[0062] In this embodiment, the comprehensive performance of a chemical product applied to a wastewater pipe network at a pilot site was evaluated, such as... Figure 3 As shown, the outlet of the sewage pipe 22 at the pilot site is connected to the S::CAN sensor 6 and the odor monitoring system 7. The testing methods for the control effects on odor, corrosion, and greenhouse gases are the same as in the previous embodiment, including online monitoring and manual sampling measurement. Figure 4 As shown, the outlet of the sewage pipe 22 at the pilot site is connected to the SBR reactor 18. The test results for its contribution to improving the quality and efficiency of the downstream sewage treatment plant and its impact on subsequent sewage treatment are the same as those in Example 1.

[0063] Example 5:

[0064] In this embodiment, different dosing methods are used to add chemicals to control sulfides and methane in the sewage pipe network, and the control effect is evaluated. Figure 1 As shown, the product can be added manually at the first dosing port 12 periodically, or online using the automatic control system 17. Periodic dosing is divided into two modes: one using low concentration and high frequency, and the other using high concentration and low frequency. Online dosing is controlled by the model and algorithm in the automatic control system to start and stop the second peristaltic pump 11. The amount of agent added is calculated by the developed algorithm.

[0065] Similar to Examples 1, 2, and 3, the effects of different dosing methods were evaluated by comparing the indicators monitored by the experimental line and the control line. Similar to Example 4, different dosing methods used in the pilot plant can also be evaluated in this way.

[0066] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for evaluating chemical dosing strategies in sewage pipe networks, characterized in that, The evaluation assesses the effectiveness of different dosing methods in controlling odor and corrosion in wastewater pipe networks, its contribution to greenhouse gas emission reduction and efficiency improvement in wastewater pipe networks, and its ecotoxicity to downstream wastewater treatment plants. The evaluation methods include the following procedures: (1) A simulation system for the actual sewage pipe network was constructed. The culture environment and biochemical properties of the simulation system used to test the product were similar to those of the actual pipe network. The simulation system was divided into a control line and an experimental line. Both lines were equipped with a pipe network reactor and S::CAN sensor, N2O sensor, CH4 sensor and odor monitoring system that could detect the operating indicators in real time. (2) The test product is added to the experimental line on the simulation system and the reagent addition strategy is evaluated by comparing the experimental line with the control line; The simulation system includes a wastewater storage tank (1), a test product stock solution (2), a first pipeline reactor (3), a second pipeline reactor (4), a third pipeline reactor (5), an S::CAN sensor (6), an odor monitoring system (7), an N2O sensor (8), a CH4 sensor (9), a first peristaltic pump (10), a second peristaltic pump (11), a first dosing port (12), a first manual sampling port (13), a second dosing port (14), a second manual sampling port (15), a third manual sampling port (16), and an automatic control system (17). The sewage storage tank (1) is connected to the first pipeline reactor (3), the second pipeline reactor (4), and the third pipeline reactor (5) in sequence through pipelines. The first peristaltic pump (10) and the first dosing port (12) are installed on the pipeline connecting the sewage storage tank (1) and the first pipeline reactor (3). The first manual sampling port (13) is installed on the pipeline connecting the first pipeline reactor (3) and the second pipeline reactor (4). The second dosing port (14) is installed on the pipeline connecting the second pipeline reactor (4) and the third pipeline reactor (5). A third manual sampling port (16) is provided on the pipeline connecting the third pipeline reactor (5) and the S::CAN sensor (6), and a second manual sampling port (15) is provided on the pipeline connecting the third pipeline reactor (5) and the odor monitoring system (7); the test product storage liquid (2) is connected to the first dosing port (12) through the second peristaltic pump (11), and the test product storage liquid (2) is also connected to the second dosing port (14) through the second peristaltic pump (11), and the second peristaltic pump (11) is electrically connected to the automatic control system (17); The simulation system may include a wastewater storage tank (1), a test product stock solution (2), a first pipeline reactor (3), a second pipeline reactor (4), a third pipeline reactor (5), an S::CAN sensor (6), an odor monitoring system (7), an N2O sensor (8), a CH4 sensor (9), a first peristaltic pump (10), a second peristaltic pump (11), a first dosing port (12), a first manual sampling port (13), a second dosing port (14), a third manual sampling port (16), an automatic control system (17), an SBR reactor (18), a third peristaltic pump (19), an aeration pump (20), a fourth manual sampling port (21), and wastewater pipelines (22). The wastewater storage tank (1) is connected in sequence to the first pipeline reactor (3), the second pipeline reactor (4), and the third pipeline reactor (5) via pipelines. A first peristaltic pump (10) and a first dosing port (12) are installed on the pipeline connecting the wastewater storage tank (1) and the first pipeline reactor (3). A first manual sampling port (13) is installed on the pipeline connecting the first pipeline reactor (3) and the second pipeline reactor (4). A second dosing port (14) is installed on the pipeline connecting the second pipeline reactor (4) and the third pipeline reactor (5). An SBR reactor (18) is installed between the third pipeline reactor (5) and the S::CAN sensor (6). The pipeline connecting the three-pipe reactor (5) and the SBR reactor (18) is equipped with a third manual sampling port (16) and a third peristaltic pump (19). The pipeline connecting the SBR reactor (18) and the S::CAN sensor (6) is equipped with a fourth manual sampling port (21). The pipeline connecting the bottom of the SBR reactor (18) is equipped with an aeration pump (20). The test product stock solution (2) is connected to the first dosing port (12) through the second peristaltic pump (11). The test product stock solution (2) is also connected to the second dosing port (14) through the second peristaltic pump (11). The second peristaltic pump (11) is electrically connected to the automatic control system (17). The testing phase is divided into two states: continuous online measurement and manual sampling analysis with the operation paused. The chemical indicators tested were obtained by direct online measurement of long-term continuous data from sensors on the simulation system, as well as discrete data obtained by manual sampling. The biological indicators tested were obtained by manual sampling and biological analysis, including the viability of microorganisms, enzyme activity related to microbial metabolism, and microbial population characteristics, in order to evaluate the effects of various chemical and biological products. The data output from the simulated system's pipeline reactor after it has been replaced with actual on-site pipelines can be used to evaluate the effects of pilot-scale or actual applications, enabling a simple and rapid evaluation of reagent dosing strategies. The evaluation method for chemical dosing strategies in sewage pipe networks can assess the overall performance of chemicals and the effects of different dosing methods. It provides performance assurance and potential problem prevention before the product is widely used in practice, and achieves a comprehensive measurement of the effect of the entire sewage treatment system to determine whether the product can be widely used in practice.

2. The method for evaluating the dosing strategy of chemicals in a sewage pipe network as described in claim 1, characterized in that, The control and experimental lines of the simulation system include at least two sequentially connected pipeline reactors, whose physical parameters are similar to those of the actual pipeline network.

3. The method for evaluating the dosing strategy of chemicals in a sewage pipe network as described in claim 2, characterized in that, The odor monitoring system can continuously monitor ammonia and volatile sulfur compounds such as methanethiol, dimethyl sulfide, and dimethyl disulfide to evaluate the effectiveness of the tested products in controlling odor gases; the N2O and CH4 sensors can monitor changes in N2O and CH4 concentrations in real time to evaluate the contribution of the tested products to greenhouse gas emission reduction; the S::CAN sensor can continuously measure H2O and CH4 concentrations. - H2S, based on corrosion algorithms to evaluate the effectiveness of test products in controlling concrete corrosion; S::CAN sensor can continuously measure COD, TSS, , The aim is to assess the impact of the tested products on downstream quality and efficiency improvement, as well as their ecotoxicity.

4. The method for evaluating the dosing strategy of chemicals in a sewage pipe network as described in claim 3, characterized in that, The testing phase is divided into three stages: steady state, product addition, and recovery.

5. The method for evaluating the dosing strategy of chemicals in a sewage pipe network as described in claim 1, characterized in that, The product can be added in the following ways: low dose, high frequency; medium dose, medium frequency; high dose, low frequency; or online automatic addition via an automatic control system.

6. The method for evaluating the dosing strategy of chemicals in a sewage pipe network as described in claim 1, characterized in that, Pipeline reactors, including SBR or AO reactors, are used to assess the impact of test products added to the pipeline on subsequent biological wastewater treatment.

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