Ecological water power regulation and control method based on dissolved oxygen threshold value
By using an eco-hydrodynamic regulation method based on dissolved oxygen threshold, river data is monitored and ROC curves are constructed to calculate and regulate flow velocity. This solves the problem of urban rivers turning black and smelly seasonally or after rain, and achieves precise regulation and sustainable ecological balance with low energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-23
- Publication Date
- 2026-04-10
AI Technical Summary
Even after treatment, urban waterways are still prone to seasonal or post-rain blackening and foul odor. Existing treatment methods are energy-intensive, cause significant disturbance, and are difficult to sustainably maintain ecological balance.
The ecological hydrodynamic regulation method based on dissolved oxygen thresholds constructs an ROC curve of oxygen consumption rate versus black and odorous state by monitoring dissolved oxygen concentration, water temperature, flow velocity, redox potential and rainfall data in the river channel. It calculates and regulates flow velocity and adopts gravity scheduling or low-lift water replenishment to achieve pre-identification and precise regulation of black and odorous water bodies.
It achieves low-energy hydrodynamic regulation, avoids energy waste, and provides clear basis for flow velocity regulation, promoting the development of urban water body management towards systematization, intelligence, and long-term effectiveness.
Smart Images
Figure CN121836099A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of urban water environment regulation and relates to methods for river water body management, specifically an ecological hydrodynamic regulation method based on dissolved oxygen threshold. Background Technology
[0002] Due to the accumulation of pollution loads and the release of pollutants from sediments, urban rivers have long suffered from water quality deterioration and black and odorous conditions. To improve the urban water environment, my country implemented the "Water Pollution Prevention and Control Action Plan" in 2015. Through systematic treatment, pollution source control and interception, and ecological restoration, significant progress has been made in the treatment of black and odorous water bodies. However, some urban rivers still experience seasonal "return to black and odorous conditions" or sudden changes in water quality after rain. Existing treatment methods, such as aeration, fresh water replenishment, and sediment dredging, can increase dissolved oxygen concentration in the water in the short term, but they generally suffer from high energy consumption, significant disturbance, and difficulty in maintaining sustainable ecological balance. Summary of the Invention
[0003] Purpose of the invention: The purpose of this invention is to provide a low-energy-consumption ecological hydrodynamic regulation method based on dissolved oxygen threshold to address the problem of seasonal or post-rain blackening and odor recurrence that is still prone to occur after urban river management.
[0004] Technical solution: The present invention provides an ecological hydrodynamic regulation method based on dissolved oxygen threshold, comprising:
[0005] S1: Obtain dissolved oxygen concentration, water temperature, flow velocity, redox potential and rainfall data for the target river over several consecutive days; if the river is already in a black and odorous state at the beginning of the monitoring period and the dissolved oxygen shows a continuous downward trend, proceed to step S6.
[0006] S2: Calculate the oxygen consumption rate based on changes in dissolved oxygen concentration. ;
[0007] S3: Oxygen Consumption Rate The ROC curve for the black and smelly state was compared with that of the Youden index. The oxygen consumption rate corresponding to the maximum value is used as the baseline threshold. ;
[0008] S4: Based on the base threshold Calculate the threshold for determining the recurrence of black and odorous water bodies. ,in This is the temperature determination coefficient; The determination coefficient after rain; The coefficient for determining sediment activity;
[0009] S5: Based on oxygen consumption rate Recurrence determination threshold ,like To maintain the current flow velocity of the river channel; such as And continue for a period of time, then proceed to step S6;
[0010] S6: Calculate and regulate flow rate Gravity regulation or low-lift water replenishment can be used to increase the average flow velocity of the river cross-section to the controlled flow velocity. ; This is the temperature amplification factor; This is the amplification factor for sediment activity; The basic flow velocity of the river channel; This is the disturbance correction value; This is a rainfall indication value.
[0011] Furthermore, the black and odorous state is characterized by dissolved oxygen concentration. This serves as the basis for judgment.
[0012] Furthermore, in step S1, continuous monitoring is conducted for no less than 5 days.
[0013] Furthermore, in step S2, the oxygen consumption rate The calculation employs a trend estimation method, which includes linear regression, Trend estimation method, moving average difference method.
[0014] Furthermore, when the sample size is lower than a set value, a linear fitting method is used to calculate the oxygen consumption rate. .
[0015] Furthermore, in step S3, the ROC curve uses the black and odorous state as the determination variable and the oxygen consumption rate as the criterion. Use as the independent variable to calculate the true positive rate. With false positive rate The changing relationship.
[0016] Furthermore, in step S3, the Youden index The calculation formula is: .
[0017] Furthermore, in step S3, the ROC curve is constructed based on historical data, with a data volume of no less than a set number of data sets to ensure curve smoothness; if the data volume is less than a set number of data sets, the ROC curve is smoothed using cubic splines to avoid line distortion.
[0018] Further, in step S4, when hour, =1.0; when hour, =0.95; when hour, =0.85; when hour, =0.825; when hour, =0.80;
[0019] Within 48 hours after the rain, Take 0.9; otherwise, Set the value to 1.0;
[0020] Redox potential , Take 0.9; otherwise, Take 1.0.
[0021] Furthermore, in step S6, when hour, =1.1; when hour, =1.4; when hour, =1.7; when hour, =1.85; when hour, =2.0;
[0022] Redox potential , Take 1.2~1.4; otherwise, Set the value to 1.0;
[0023] Take 0.02~0.12 m / s and use the minimum sustained flow velocity of the river section as a substitute;
[0024] Use 0.1~0.4 as the starting point, and 0.2 after the rain;
[0025] Within 48 hours after the rain, =1, otherwise =0.
[0026] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:
[0027] (1) The present invention constructs a recurrence judgment threshold by means of dissolved oxygen change rate, and realizes the pre-identification of black and odorous water risk based on the threshold. Hydrodynamic regulation is only activated when the triggering conditions are met, avoiding energy waste caused by blind water replenishment. At the same time, gravity scheduling or low-lift water replenishment means have low energy consumption.
[0028] (2) After the control conditions are triggered, the present invention quantitatively calculates the control flow velocity based on water temperature, bottom sediment state and hydrodynamic conditions, so as to achieve the matching of control intensity with environmental conditions, and make the river flow velocity regulation have a clear basis and controllable range.
[0029] (3) This invention constructs an integrated mechanism of “monitoring-early warning-regulation” to realize early warning and proactive intervention of the risk of polluted rivers turning black and smelly again, and promotes the development of urban water body treatment process towards systematization, intelligence and long-term effectiveness. Attached Figure Description
[0030] Figure 1 This is a flowchart of an ecological hydrodynamic regulation method based on dissolved oxygen threshold provided by an embodiment of the present invention;
[0031] Figure 2 This refers to the dissolved oxygen during the monitoring period in this embodiment of the invention. Trendline chart;
[0032] Figure 3 This refers to the oxygen consumption rate during the monitoring period in this embodiment of the invention. ROC curves for the black and foul-smelling state;
[0033] Figure 4 Example 1 is a comparison chart of dissolved oxygen concentration in water during the monitoring and control periods;
[0034] Figure 5 Example 2 shows a comparison of dissolved oxygen concentrations in water during the monitoring and control periods. Detailed Implementation
[0035] The invention will now be further described with reference to the accompanying drawings.
[0036] like Figure 1 As shown, this embodiment of the invention provides an ecological hydrodynamic regulation method based on dissolved oxygen threshold, comprising the following steps:
[0037] S1: Obtain data on dissolved oxygen concentration, water temperature, flow velocity, redox potential, and rainfall in the target river channel. The monitoring should be conducted continuously for no less than 5 days under stable weather conditions. Sequences shorter than 3 days are easily affected by occasional disturbances, leading to biased trend judgment. If the river channel is already in a black and odorous state at the beginning of the monitoring period and the dissolved oxygen shows a continuous downward trend, proceed to step S6.
[0038] S2: Calculate the oxygen consumption rate based on changes in dissolved oxygen concentration. .
[0039] oxygen consumption rate The rate at which dissolved oxygen in water changes over time is a key indicator for determining whether a river is in an aerobic or anaerobic state. Oxygen consumption rate The calculation can employ various trend estimation methods, including linear regression, Trend estimation method, moving average difference method, etc., are used in this embodiment. The trend estimation method, which calculates the median slope, is insensitive to outliers and can robustly reflect the overall trend of dissolved oxygen concentration changes in small samples and noisy data, making it suitable for highly fluctuating scenarios such as black and odorous water bodies. When the sample size is less than 5, the linear fitting method can be selected to calculate the oxygen consumption rate. .
[0040] S3: Oxygen Consumption Rate The ROC curve for the black and smelly state was compared with that of the Youden index. The oxygen consumption rate corresponding to the maximum value (i.e., the Youden optimum) is used as the baseline threshold. This allows the basic threshold to balance the sensitivity and specificity of black and odor identification.
[0041] The determination of black and odorous status is based on the "Guidelines for the Treatment of Black and Odorous Water Bodies in Cities" (issued by the Ministry of Housing and Urban-Rural Development and the Ministry of Environmental Protection, Jianbiao
[2015] No. 130, released in August 2015), when the dissolved oxygen concentration... The water body was identified as black and odorous at that time. The state of blackness and odor is represented by the qc value; when qc=0, it indicates the water body is in a black and odorous state; when qc=1, it indicates the water body is not in a black and odorous state. The ROC curve uses the state of blackness and odor as the determining variable and the oxygen consumption rate as the criterion. Use as the independent variable to calculate the true positive rate. With false positive rate The changing relationship.
[0042] The ROC curve is constructed based on historical data, with no fewer than 30 sets of data to ensure curve smoothness; if the data set is less than 30 sets, the ROC curve is smoothed using cubic splines to avoid broken line distortion.
[0043] Youden Index The comprehensive performance used to characterize the ability to identify black and odorous substances under different oxygen consumption rates is calculated using the following formula: .
[0044] S4: Based on the base threshold Calculate the threshold for determining the recurrence of black and odorous water bodies. ,in For temperature determination coefficient, when hour, =1.0; when hour, =0.95; when hour, =0.85; when hour, =0.825; when hour, =0.80; This is the post-rain determination coefficient, within 48 hours after the rain. Take 0.9; otherwise, Set the value to 1.0; The determination coefficient for sediment activity is the redox potential. , Take 0.9; otherwise, Take 1.0.
[0045] S5: Based on oxygen consumption rate Recurrence determination threshold ,like To maintain the current flow velocity of the river channel; such as And continue for a period of time, then proceed to step S6.
[0046] The purpose of steps S2 to S5 is to determine, based on the trend of dissolved oxygen concentration changes, whether a river that was in a healthy state at the beginning of the monitoring period has entered a state of black and odorous evolution. This can effectively distinguish between a temporary decrease in dissolved oxygen and a continuous oxygen consumption process, thereby avoiding misjudgments caused by short-term fluctuations in dissolved oxygen and reducing unnecessary control operations and resource waste.
[0047] S6: Calculate and regulate flow rate By employing gravity regulation or low-lift water replenishment methods, high-intensity aeration or mechanical agitation is avoided, thereby increasing the average flow velocity of the river cross-section to the controlled flow velocity under relatively low energy consumption conditions. ; For temperature amplification factor, when hour, =1.1; when hour, =1.4; when hour, =1.7; when hour, =1.85; when hour, =2.0; The amplification factor of sediment activity, and the redox potential. , Take 1.2~1.4; otherwise, Set the value to 1.0; The basic flow velocity of the river channel is usually taken as 0.02~0.12 m / s, and can be replaced by the minimum sustained flow velocity of the river section; This is a disturbance correction value, usually taken as 0.1~0.4, and 0.2 is usually taken as the starting point after rain; This is the rainfall indicator value, within 48 hours after the rain. =1, otherwise =0.
[0048] The formula for calculating the flow velocity regulation is based on the theory of water reoxygenation dynamics. The model (which establishes an empirical linear relationship between the reoxygenation rate and hydrodynamic conditions by introducing temperature and rainfall disturbance correction terms) is used to minimize the flow velocity.
[0049] Steps S4 and S6 introduce temperature, hydrodynamic, and meteorological disturbance judgment coefficients and amplification coefficients, which fully reflect the comprehensive consideration of seasonality and hydrodynamic disturbance mechanisms, making the threshold judgment dynamically adaptable.
[0050] Two specific examples are given below.
[0051] Example 1: A polluted river (No. 1) underwent continuous monitoring for 10 days. During the monitoring period, the average water temperature was 26.1℃, the baseline flow velocity was 0.023m / s, the oxidation-reduction potential was <0mV, and there was no rainfall. The monitoring results showed that the dissolved oxygen concentration in the polluted river (No. 1) decreased from 2.19mg / L to 1.53mg / L. Specifically, on the 4th day of monitoring, the dissolved oxygen concentration decreased to 1.93mg / L (below the 2mg / L threshold). Based on this, it was determined that the river entered a black and odorous state from the 4th day of the monitoring period and maintained this black and odorous characteristic from the 4th to the 10th day, corresponding to a qc value of 1.
[0052] Based on dissolved oxygen data, using In The estimator performs trend analysis, such as Figure 2 As shown, the oxygen consumption rate is obtained. =0.0833 According to the oxygen consumption rate And qc value, in In In AUC, plot the ROC curve and calculate the Youden exponent. , The oxygen consumption rate at which the maximum value is taken as the baseline threshold. ,like Figure 3 As shown, the basic threshold is obtained. It is 0.096 Given a water temperature of 26.1℃, what is the temperature determination coefficient? =0.85; No rainfall, post-rain determination coefficient =1; Redox potential < 0mV, sediment activity determination coefficient The threshold for recurrence determination is calculated to be 0.9. =0.85×1×0.9×0.096=0.0734 .observe If the flow continues for more than 6 hours, an alert will be triggered, and the flow rate needs to be calculated and adjusted. =1.7×1.3×0.025×(1+0.1×0)=0.051m / s.
[0053] Increase the cross-sectional average flow velocity to the controlled flow velocity After maintaining this level for 12 hours, a 9-day control period was initiated. During this period, the dissolved oxygen concentration increased from 1.65 mg / L to 3.89 mg / L (above the 2 mg / L threshold), achieving the effective reoxygenation and treatment goals for the black and odorous water body. The comparison of dissolved oxygen concentrations during the monitoring and control periods is shown below. Figure 4 As shown, days 1-10 are the monitoring period, and days 11-19 are the control period.
[0054] Example 2: A polluted river (No. 2) underwent continuous monitoring for 8 days. During the monitoring period, the average water temperature was 23.3℃, the baseline flow velocity was 0.063 m / s, and the oxidation-reduction potential was <0 mV. There was no rainfall during this period. Monitoring results showed that the dissolved oxygen concentration in the polluted river (No. 2) decreased from 1.98 mg / L to 1.40 mg / L (below the 2 mg / L threshold), indicating that the water body was in a persistent black and odorous state. Since the initial dissolved oxygen concentration was already below the black and odorous threshold, and the black and odorous state had persisted for 8 days, the process directly entered the regulation phase, and the regulation flow velocity was calculated. =1.4×1.2×0.063×(1+0.1×0)=0.106m / s.
[0055] Increase the cross-sectional average flow velocity to the controlled flow velocity The system was maintained for 12 hours before entering a 5-day regulation period. During this period, the dissolved oxygen concentration increased from 1.44 mg / L to 3.89 mg / L (above the 2 mg / L threshold), achieving the goal of effective reoxygenation and treatment of the black and odorous water body. The comparison of dissolved oxygen concentration between the monitoring and regulation periods is shown below. Figure 5 As shown, days 1-8 are the monitoring period, and days 9-13 are the control period.
Claims
1. An ecological hydrodynamic regulation method based on dissolved oxygen threshold, characterized in that, include: S1: Obtain dissolved oxygen concentration, water temperature, flow velocity, redox potential and rainfall data for the target river over several consecutive days; if the river is already in a black and odorous state at the beginning of the monitoring period and the dissolved oxygen shows a continuous downward trend, proceed to step S6. S2: Calculate the oxygen consumption rate based on changes in dissolved oxygen concentration. ; S3: Oxygen Consumption Rate The ROC curve for the black and smelly state was compared with that of the Youden index. The oxygen consumption rate corresponding to the maximum value is used as the baseline threshold. ; S4: Based on the base threshold Calculate the threshold for determining the recurrence of black and odorous water bodies. ,in This is the temperature determination coefficient; The determination coefficient after rain; The coefficient for determining sediment activity; S5: Based on oxygen consumption rate Recurrence determination threshold ,like To maintain the current flow velocity of the river channel; such as And continue for a period of time, then proceed to step S6; S6: Calculate and regulate flow rate Gravity regulation or low-lift water replenishment can be used to increase the average flow velocity of the river cross-section to the controlled flow velocity. ; This is the temperature amplification factor; This is the amplification factor for sediment activity; The basic flow velocity of the river channel; This is the disturbance correction value; This is a rainfall indication value.
2. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 1, characterized in that, The black and smelly state is determined by the dissolved oxygen concentration. This serves as the basis for judgment.
3. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 1, characterized in that, In step S1, continuous monitoring shall be conducted for no less than 5 days.
4. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 1, characterized in that, In step S2, the oxygen consumption rate The calculation employs a trend estimation method, which includes linear regression, Trend estimation method, moving average difference method.
5. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 4, characterized in that, When the sample size is lower than the set value, the oxygen consumption rate is calculated using a linear fitting method. .
6. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 1, characterized in that, In step S3, the ROC curve uses the black and smelly state as the determination variable and the oxygen consumption rate as the criterion. Use as the independent variable to calculate the true positive rate. With false positive rate The changing relationship.
7. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 6, characterized in that, In step S3, the Youden index The calculation formula is: .
8. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 1, characterized in that, In step S3, the ROC curve is constructed based on historical data, with a data volume of no less than a set number of data sets to ensure curve smoothness; if the data volume is less than a set number of data sets, the ROC curve is smoothed using cubic splines to avoid line distortion.
9. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 1, characterized in that, In step S4, when hour, =1.0; when hour, =0.95; when hour, =0.85; when hour, =0.825; when hour, =0.80; Within 48 hours after the rain, Take 0.9; otherwise, Set the value to 1.0; Redox potential , Take 0.9; otherwise, Take 1.
0.
10. The ecological hydrodynamic regulation method based on dissolved oxygen threshold according to claim 1, characterized in that, In step S6, when hour, =1.1; when hour, =1.4; when hour, =1.7; when hour, =1.85; when hour, =2.0; Redox potential , Take a value of 1.2 to 1.4; otherwise, Set the value to 1.0; Take 0.02~0.12 m / s and use the minimum sustained flow velocity of the river section as a substitute; Use 0.1~0.4 as the starting point, and 0.2 after the rain; Within 48 hours after the rain, =1, otherwise =0.