Ship sewage discharge management and control system and method based on water quality sensing and diffusion model

Abstract

This invention relates to a ship sewage discharge control system and method based on a water quality sensing and diffusion model. The system includes an AIS data acquisition module, a water quality sensing module, a discharge equipment monitoring module, a discharge impact module, a decision command generation module, and a discharge data storage module. The AIS data acquisition module is used to acquire the ship's position, ground speed, heading, and timestamp information in real time. The water quality sensing module is used to detect the background concentration of pollutants in the receiving water around the ship in real time. The discharge equipment monitoring module is used to monitor the operating status of the discharge equipment. The discharge impact module has a built-in two-dimensional advection-diffusion model. The decision command generation module is used to generate discharge decision commands that allow or suspend discharge. This system uses dynamic strategies to precisely regulate ship sewage discharge, providing environmentally friendly intelligent control for ship sewage discharge. The discharge data storage module replaces log recording, providing a data foundation for subsequent pollution research.

Description

Technical Field

[0001] This invention relates to the field of ship pollution prevention technology, and in particular to a ship wastewater discharge control system and method based on a water quality sensing and diffusion model. Background Technology

[0002] As the global shipping industry continues to expand, the impact of ship sewage discharge on the marine environment is increasingly attracting international attention. Sewage contains large amounts of organic matter, nutrients, and microorganisms; improper discharge can lead to eutrophication, blackening and odorization of water bodies, and damage to marine ecosystems. To regulate ship sewage discharge, the International Maritime Organization (IMO) has clearly stipulated the discharge conditions in Annex IV of the MARPOL Convention, including discharge distance, discharge speed, treatment standards, and restrictions on Particularly Sensitive Sea Areas (PSSA). Therefore, real-time monitoring and compliance assessment of ship sewage discharge have become crucial requirements for maritime regulation and environmental management.

[0003] Currently, ships are generally equipped with sewage treatment facilities, sewage pumps, sewage storage tanks, and related valves to treat, temporarily store, and discharge domestic sewage. However, the following technical limitations still exist regarding domestic sewage discharge: (1) Lack of real-time perception of receiving water bodies. Existing systems only determine whether the discharge is within a permitted geographical area, but ignore the current water quality status of that area. If a legally permitted discharge area is currently experiencing a red tide outbreak or has excessively high background pollutant concentrations, even legal discharge will exacerbate environmental degradation, lacking the ability to assess ecological tolerance. (2) Lack of ability to predict the consequences of emissions. Existing shipboard technology cannot quantify the diffusion range and concentration changes of pollutants after emissions. The diffusion effect of discharged domestic sewage varies greatly under different ship speeds and hydrological conditions. The lack of model support will lead to supervision being in a retrospective state, and it will be impossible to carry out pre-emptive prevention. (3) Lack of dynamic decision-making mechanism. The existing compliance judgment is static, that is, it is based on rules to determine whether ship sewage discharge is compliant, and lacks dynamic recommendations based on environmental capacity.

[0004] Therefore, there is an urgent need for an intelligent management and control system that can perceive the water quality of receiving water bodies in real time, dynamically predict the impact of ship sewage discharge, and link environmental data with discharge behavior. Summary of the Invention

[0005] The purpose of this invention is to provide a ship wastewater discharge control system and method based on a water quality sensing and diffusion model, in order to solve the technical problems in the prior art, such as the lack of real-time sensing of the receiving water quality, the lack of prediction of the impact of pollutant diffusion after discharge, and the inability to provide dynamic discharge recommendations based on environmental carrying capacity.

[0006] In a first aspect, the technical solution adopted by the present invention is a ship wastewater discharge control system based on a water quality sensing and diffusion model, comprising: The AIS data acquisition module is used to acquire the ship's position, speed above ground, heading, and timestamp information in real time; the water quality sensing module is installed below the waterline or at the sea intake for real-time monitoring of the receiving water around the ship. The background concentration of pollutants; the discharge equipment monitoring module, used to monitor the operating status of the ship's sewage discharge equipment, and to detect when the discharge equipment is turned on. The system generates corresponding status signals when the system is turned on or off. The sewage discharge impact module incorporates a two-dimensional advection-diffusion model. This model is used to calculate the diffusion concentration field distribution of pollutants after the discharge of shipboard sewage, based on the speed data provided by the AIS data acquisition module, the status signals provided by the discharge equipment monitoring module, and the background pollutant concentration detected by the water quality sensing module. The model then outputs the discharge impact prediction results. The advection velocity component in the two-dimensional advection-diffusion model is coupled with the speed data. The decision instruction generation module is connected to the AIS data acquisition module, water quality sensing module, and pollution impact module, respectively, and is used to generate emission decision instructions that allow or suspend emissions based on the ship's location, background concentration of pollutants, and emission impact prediction results.

[0007] The beneficial effects of this invention are as follows: The ship sewage discharge control system based on the aforementioned water quality sensing and diffusion model, by introducing a water quality sensing module, allows for real-time assessment of the receiving water body's environmental capacity before discharge, effectively avoiding sewage discharge in areas with excessively high pollution levels and demonstrating proactive ecological management capabilities. By constructing a two-dimensional advection-diffusion model dynamically coupled with ship speed, the system achieves quantitative prediction of pollutant diffusion trajectories and concentration distribution after discharge. It replaces traditional static rule-based judgments with controllable analysis based on environmental impact, making the approach more scientific and rational. Simultaneously, the system constructs a closed-loop data chain of navigation-discharge impact prediction-discharge through multi-dimensional data fusion and storage, enabling precise adjustment of ship sewage discharge using dynamic strategies, providing environmentally friendly intelligent management of ship sewage discharge.

[0008] Preferably, the AIS data acquisition module specifically includes: The AIS signal receiving unit is used to connect with the ship's AIS equipment and receive AIS data packets in real time. The data parsing unit, connected to the AIS signal receiving unit, is used to parse the AIS data according to the AIS data protocol. According to the report, the ship's latitude and longitude position, speed over land, heading, and timestamp information were extracted. The location compliance judgment interface unit, connected to the data parsing unit, is used to send the latitude and longitude location information to... Regional compliance judgment unit of the decision instruction generation module; The speed and heading output interface unit, connected to the data parsing unit, is used to output the ground speed and heading information. The data is sent to the sewage impact module as a coupling input parameter to couple with the advection velocity component in the two-dimensional advection-diffusion model. The time synchronization unit, connected to the data parsing unit, is used to extract the timestamp information and perform time synchronization calibration on the latitude and longitude position, ground speed, and heading.

[0009] Preferably, the sewage discharge impact module specifically includes: The model storage unit is used to store and initialize the two-dimensional advection-diffusion model; The parameter coupling unit is connected to the speed and heading output interface unit and is used to acquire the ship's ground speed and heading data, and to couple the advection velocity component with the speed data according to a preset coupling relationship, and output the coupled advection velocity parameter. The source term generation unit is connected to the emission equipment monitoring module and is used to receive the status signal output by the emission equipment, and determine the start and end time, emission location and emission intensity of the emission behavior according to the status signal to generate pollutant source term parameters. The background concentration input unit is connected to the water quality sensing module and is used to obtain the background concentration of pollutants in the receiving water around the ship, and to use the background concentration of pollutants as the boundary condition of the two-dimensional advection-diffusion model. The numerical solution unit is connected to the model storage unit, parameter coupling unit, source term generation unit and background concentration input unit respectively. It is used to solve the two-dimensional advection-diffusion model based on the coupled advection velocity parameters, pollutant source term parameters and pollutant background concentration, and calculate the spatiotemporal distribution of the diffusion concentration field of pollutants in the receiving water body after the discharge of ship sewage. The prediction result output unit, connected to the numerical solution unit, is used to output the calculated spatiotemporal distribution of the diffusion concentration field as the emission impact prediction result to the decision instruction generation module.

[0010] Preferably, the coupled advection velocity parameter is specifically expressed as follows: ;in, Indicates the ship's speed; Indicates the ship's heading angle; Indicates the influence coefficient of speed; and Both represent the advection velocity component; The pollutant source term parameters are specifically represented as follows: ; in, This indicates the amount of wastewater discharged per unit of time. Indicates the initial concentration of pollutants in the discharged wastewater; surface Indicates the spatial coordinates of the initial emission point; This represents the Dirac function, used to characterize point source emissions.

[0011] Preferably, the two-dimensional advection-diffusion model is specifically expressed as follows: in, This represents the background concentration of pollutants at time t in two-dimensional space (x, y); and Representing water bodies Diffusion coefficients in the transverse and longitudinal directions.

[0012] Preferably, the background concentration of the pollutants specifically includes one or more of the following: total nitrogen concentration, total phosphorus concentration, chemical oxygen demand, suspended solids content, and coliform bacteria concentration.

[0013] Preferably, the emission monitoring module specifically includes: The signal acquisition unit is used to acquire the on or off status of the emission equipment in real time and generate corresponding status signals. The storage capacity monitoring module is used to monitor the storage capacity of the wastewater storage tank and generate data on changes in storage capacity. The emission behavior identification module is connected to the signal acquisition unit and the storage monitoring unit, respectively, and is used to identify the start and end time of the emission behavior based on the status signal and the storage change data, and to calculate the amount of sewage discharged per unit time.

[0014] Preferably, the decision instruction generation module specifically includes: The regional compliance judgment unit, connected to the AIS data acquisition module, is used to determine whether the current sea area meets the emission area requirements based on the ship's position, and to generate a first judgment result; An environmental capacity judgment unit, connected to the water quality sensing module, is used to judge whether the receiving water body has environmental capacity based on the background concentration of pollutants in the receiving water body around the ship, and to generate a second judgment result. The diffusion impact judgment unit, connected to the pollution discharge impact module, is used to judge whether the concentration of pollutants after discharge can be diluted to below the safety threshold within a preset time based on the emission impact prediction result, and generate a third judgment result; The integrated decision-making unit is connected to the regional compliance judgment unit, the environmental capacity judgment unit, and the diffusion impact judgment unit, respectively, and is used to generate emission decision instructions based on the first judgment result, the second judgment result, and the third judgment result. Specifically, when the first judgment result, the second judgment result, and the third judgment result are all yes, the integrated decision-making unit generates a decision instruction to allow emissions; when any judgment result is no, the integrated decision-making unit generates a decision instruction to suspend emissions.

[0015] Preferably, the system also includes an emission data storage module for storing navigation status data, water quality monitoring data, emission equipment operation status data, and emission impact prediction results during the discharge of ship sewage.

[0016] Secondly, a method for controlling ship wastewater discharge based on a water quality sensing and diffusion model, which includes the following steps: S1. Real-time collection of ship navigation status data, water quality data of the receiving water body around the ship, and operational status data of the discharge equipment; wherein, the ship navigation status data includes at least the ship's latitude and longitude position, speed above ground, heading, and timestamp information, which is obtained through the AIS data acquisition module; the operational status data of the discharge equipment includes the on or off status of the discharge equipment, which is obtained through the discharge equipment monitoring module; S2. Identify the discharge behavior of shipboard domestic sewage based on the operating status data of the discharge equipment, and determine the discharge source parameters; when the discharge equipment is detected to be turned on, it is determined that the discharge behavior has started, the discharge start time and discharge location are recorded, and the sewage discharge volume is obtained based on the liquid level change of the sewage storage tank; when the discharge equipment is detected to be turned off, it is determined that the discharge behavior has ended; the discharge source parameters include the sewage discharge volume per unit time, the initial concentration of pollutants in the discharged sewage, and the spatial coordinates of the discharge point; S3. Call the two-dimensional advection-diffusion model, and calculate the spatiotemporal distribution of the diffusion concentration field of pollutants in the receiving water body after the discharge of domestic sewage from the ship, based on the ship's navigation status data, the background concentration of pollutants in the water quality data of the receiving water body around the ship, and the emission source term parameters, and output the emission impact prediction results. S4. Based on the collected ship location information, water quality data of the receiving water body around the ship, and the emission impact prediction results output in step S3, determine the compliance of the ship's sewage discharge behavior and generate a discharge decision instruction; the compliance determination specifically includes: Based on the vessel's location information, determine whether the current sea area meets the emission area requirements and generate a first judgment result; Based on the background concentration of pollutants in the water quality data of the receiving water body around the ship, determine whether the receiving water body has environmental capacity, and generate a second judgment result; Based on the emission impact prediction results, determine whether the pollutant concentration after emission can be diluted to below the safety threshold within a preset time, and generate a third judgment result; When the first, second, and third judgment results are all affirmative, a decision instruction to allow emissions is generated; when any judgment result is negative, a decision instruction to suspend emissions is generated. S5. Based on the emission decision command generated in step S4, execute the corresponding control operations and output prompt information to the ship operator; wherein, when the decision command is to allow emission, automatically control the emission equipment to turn on, allowing the discharge of domestic sewage; when the decision command is to suspend emission, prohibit the emission equipment from turning on, and output emission suggestion information to the ship operator. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the ship sewage discharge control system based on the water quality sensing and diffusion model of the present invention. Figure 2 This is a schematic diagram of the process for the ship sewage discharge control method based on the water quality sensing and diffusion model of the present invention. Detailed Implementation

[0018] The invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can implement it based on the description. The scope of protection of the invention is not limited to these specific embodiments.

[0019] In the description of the embodiments of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setting," "installing," "connecting," and "linking" should be interpreted broadly, for example, they can refer to fixed connections or detachable connections. The term "connection" can refer to a direct or integral connection; it can be mechanical or electrical; it can be a direct connection or an indirect connection via an intermediate medium; or it can be a connection within two components. Those skilled in the art will understand the specific meaning of these terms in this application based on the specific circumstances.

[0020] like Figure 1 As shown, this invention provides a ship wastewater discharge control system based on a water quality sensing and diffusion model, comprising: an AIS data acquisition module, a water quality sensing module, a discharge equipment monitoring module, a discharge impact module, a decision command generation module, and a discharge data storage module. All modules are interconnected via an internal ship data bus to achieve real-time data interaction and collaborative operation.

[0021] Specifically, the AIS data acquisition module receives and parses ship AIS data in real time using the ship's existing AIS equipment. This module includes an AIS signal receiving unit, a data parsing unit, a position compliance judgment interface unit, a speed and heading output interface unit, and a time synchronization unit. This module is not only used for basic position compliance judgment but also responsible for synchronously transmitting real-time speed data to the pollution impact module as a dynamic input parameter in the diffusion model.

[0022] The system comprises several components: an AIS signal receiving unit receives AIS messages, a data parsing unit parses the messages to extract the ship's latitude and longitude position, speed over ground (SOG), heading (COG), and timestamp; a position compliance judgment interface unit sends the ship's latitude and longitude position information to the area compliance judgment unit of the decision command generation module; a speed and heading output interface unit sends the speed over ground and heading information to the parameter coupling unit of the pollution impact module; and a time synchronization unit extracts the timestamp information and performs time synchronization calibration on the data output from all AIS data acquisition modules to ensure data timing consistency.

[0023] Specifically, the water quality sensing module is installed at the seabed intake of the ship to ensure that the water sample measured is the actual seawater around the ship that will soon enter the ship's cooling water system. The module integrates a multi-parameter water quality sensor to detect total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), suspended solids (SS), and coliform bacteria concentration.

[0024] The water quality sensing module itself features a corrosion-resistant and biofilm-resistant design. Its sensor probe and housing are made of titanium alloy or 316L marine-grade stainless steel, with a nano-anti-corrosion coating to adapt to high-salinity seawater environments. It is also equipped with a mechanical brush driven by a timed motor to remove biofilm from the probe surface at preset intervals.

[0025] Specifically, the emission equipment monitoring module is used to monitor the operational status of the ship's sewage discharge equipment. This module includes a signal acquisition unit, a storage monitoring unit, and an emission behavior identification unit. As one of the important input parameters for ship emission sources, this module is used for the dynamic updating of pollutant source items in the pollution impact assessment module.

[0026] The signal acquisition unit is connected to the contactor auxiliary contacts of the discharge pump and the limit switch of the discharge valve via a digital input interface, acquiring the on / off status of the equipment in real time and generating corresponding status signals. The storage capacity monitoring unit uses an ultrasonic level sensor installed inside the wastewater storage tank to monitor liquid level changes in real time and generate storage capacity change data. The discharge behavior recognition unit is connected to both the signal acquisition unit and the storage capacity monitoring unit. When it detects that the discharge equipment is on and the storage capacity is continuously decreasing, it determines it as a valid discharge event, records the start and end times of the discharge, and calculates the wastewater discharge volume per unit time based on the storage capacity change rate. The discharge behavior recognition unit outputs the start and end times, discharge location, and discharge intensity of the discharge behavior as discharge source term parameters to the source term generation unit of the wastewater impact module.

[0027] When the emission equipment is on, the system introduces the corresponding pollutant input into the pollution impact assessment model; when the emission equipment is off, the pollutant input is terminated, thereby achieving consistency between the model calculation process and the actual emission behavior.

[0028] Specifically, the pollution impact module is built into an industrial-grade embedded computer and runs a two-dimensional advection-diffusion model solver. This module includes a model storage unit, a parameter coupling unit, a source term generation unit, a background concentration input unit, a numerical solution unit, and a prediction result output unit.

[0029] The model storage unit stores and initializes the two-dimensional advection-diffusion model. This model serves as an environmental impact prediction tool within the pollution discharge impact assessment module. Its calculation results are used to support decisions regarding ship sewage discharge, rather than for simple mathematical modeling or theoretical analysis. The core purpose of this module is to accurately simulate the spatiotemporal distribution of horizontal diffusion concentrations of pollutants such as COD, ammonia nitrogen, total phosphorus, and fecal coliforms in domestic sewage, taking into account the characteristics of sewage discharge during ship navigation. This involves integrating dynamic parameters such as ship speed and heading with baseline data of the external water environment. The goal is to provide a quantitative assessment basis for compliance determination, achieving the dual control objectives of compliant discharge and low environmental impact.

[0030] The two-dimensional advection-diffusion model is specifically represented as follows: in, This represents the background concentration of pollutants at time t in two-dimensional space (x, y); and The diffusion coefficients of water in the horizontal and vertical directions, respectively.

[0031] The parameter coupling unit is connected to the speed and heading output interface unit and is used to acquire the ship's ground speed and heading data. The advection velocity component is coupled with the flight speed data according to a preset coupling relationship, and the coupled advection velocity parameter is output.

[0032] The coupled advection velocity parameter is specifically expressed as follows: ;in, Indicates the ship's speed; Indicates the ship's heading angle; Indicates the influence coefficient of speed; and Both represent the advection velocity component. This coupling mechanism makes it easier for pollutants to diffuse along the course of the ship under high-speed navigation conditions, while the diffusion process is mainly lateral diffusion under low-speed navigation conditions.

[0033] In the pollution impact assessment process, the diffusion model treats the discharge of ship sewage as a pollutant input event. When the discharge equipment monitoring module detects that the discharge valve is open or the discharge pump is started, the diffusion model calculation unit generates a pollutant input at the corresponding ship's current location; the intensity of the pollutant input is determined based on the sewage discharge volume and pollutant concentration in the sewage per unit time; when the discharge equipment is shut down, the pollutant input terminates.

[0034] The source term generation unit is connected to the emission equipment monitoring module and is used to receive the status signal output by the emission equipment, and determine the start and end time, emission location and emission intensity of the emission behavior based on the status signal to generate pollutant source term parameters.

[0035] The pollutant source term parameters are specifically represented as follows: ; in, This indicates the amount of wastewater discharged per unit of time. Indicates the initial concentration of pollutants in the discharged wastewater; Indicates the spatial coordinates of the initial emission point; This represents the Dirac function, used to characterize point source emissions.

[0036] The aforementioned two-dimensional advection-diffusion model is used in the sewage impact module to predict the environmental impact of ship sewage discharge behavior, thereby supporting intelligent discharge decision-making.

[0037] The background concentration input unit is connected to the water quality sensing module and is used to obtain the background concentration of pollutants in the receiving water around the ship, and to use the background concentration of pollutants as the boundary condition of the two-dimensional advection-diffusion model.

[0038] The numerical solution unit is connected to the model storage unit, parameter coupling unit, source term generation unit, and background concentration input unit, respectively, and is used to solve the two-dimensional advection-diffusion model based on the coupled advection velocity parameters, pollutant source term parameters, and pollutant background concentration, and to calculate the spatiotemporal distribution of the diffusion concentration field of pollutants in the receiving water body after the discharge of ship sewage.

[0039] The prediction result output unit is connected to the numerical solution unit and is used to output the calculated spatiotemporal distribution of the diffusion concentration field as the emission impact prediction result to the decision instruction generation module.

[0040] Specifically, the decision instruction generation module includes a regional compliance judgment unit, an environmental capacity judgment unit, a diffusion impact judgment unit, and a comprehensive decision-making unit.

[0041] The decision command generation module integrates environmental water quality information collected by the water quality sensing module, pollutant diffusion prediction results output by the pollution impact module, and compliance information of the discharge area to intelligently assess the ship's sewage discharge behavior. When the assessment indicates that the ship's current sea area is a permitted discharge zone, the water quality is good, and there is a certain degree of environmental tolerance, and the pollution impact assessment indicates that the discharge behavior will not have a significant adverse impact on the surrounding sea water quality, the decision command generation module issues a decision command to control the discharge equipment to start, allowing sewage discharge. When the assessment indicates that the sea area where the ship is located does not meet the discharge conditions, the decision command generation module restricts or prohibits discharge and outputs discharge recommendations to the ship's operators, including suggestions such as delaying discharge, adjusting speed, or changing the discharge area.

[0042] The regional compliance judgment unit is connected to the location compliance judgment interface unit of the AIS data acquisition module. Based on the comparison between the ship's latitude and longitude position and the built-in electronic nautical chart data, it determines whether the current sea area complies with the emission area requirements of the MARPOL Convention and generates the first judgment result.

[0043] The environmental capacity assessment unit is connected to the water quality sensing module and compares the background concentration of pollutants with a preset threshold. For example, when the background concentration of total phosphorus exceeds 0.05 mg / L (eutrophication risk threshold), the environmental capacity is determined to be insufficient, and a second assessment result is generated; otherwise, the environmental capacity is determined to be sufficient.

[0044] The diffusion impact judgment unit is connected to the prediction result output unit of the pollution discharge impact module. Based on the emission impact prediction results, it judges whether the maximum concentration within a few minutes after emission does not exceed the environmental quality standard (e.g., COD < 10 mg / L) and whether the radius of the exceeding area is less than m. If the above conditions are met, a positive third judgment result is generated; otherwise, a negative third judgment result is generated.

[0045] The integrated decision-making unit is connected to the regional compliance assessment unit, the environmental capacity assessment unit, and the diffusion impact assessment unit, respectively, and performs logical combination calculations on the first, second, and third assessment results. When all three assessment results are positive, a decision instruction to allow emissions is generated; when any assessment result is negative, a decision instruction to suspend emissions is generated, and based on the specific type of negative assessment result, corresponding emission recommendation information is matched and output, including recommendations to delay emissions, adjust speed, reduce emission pump flow, or change emission areas.

[0046] Specifically, the discharge data storage module is used to record and store relevant data during the discharge of ship sewage. The corresponding data can be used for subsequent retrospective analysis of discharge behavior, environmental impact assessment, and compliance review by regulatory authorities, thereby improving the transparency and traceability of ship sewage discharge management.

[0047] The emissions data storage module records the following data in time series: Emissions incident number, start and end times, start and end locations (latitude and longitude), speed, and heading; Water quality sensing data (minute average) for several minutes before and after discharge. Discharge flow rate, total discharge volume, and initial wastewater concentration; A snapshot of the concentration field predicted by the pollution discharge impact module (saves data every n seconds, saving the data from the previous m minutes); The decision-making basis and results of the decision instruction generation module.

[0048] This invention also provides a method for controlling shipboard sewage discharge based on a water quality sensing and diffusion model, such as... Figure 2 As shown, the method includes the following steps: S1. Real-time collection of ship navigation status data, water quality data of the receiving water body around the ship, and operational status data of the discharge equipment; wherein, the ship navigation status data includes at least the ship's latitude and longitude position, speed above ground, heading, and timestamp information, which is obtained through the AIS data acquisition module; the operational status data of the discharge equipment includes the on or off status of the discharge equipment, which is obtained through the discharge equipment monitoring module; S2. Identify the discharge behavior of shipboard domestic sewage based on the operating status data of the discharge equipment, and determine the discharge source parameters; when the discharge equipment is detected to be turned on, it is determined that the discharge behavior has started, the discharge start time and discharge location are recorded, and the sewage discharge volume is obtained based on the liquid level change of the sewage storage tank; when the discharge equipment is detected to be turned off, it is determined that the discharge behavior has ended; the discharge source parameters include the sewage discharge volume per unit time, the initial concentration of pollutants in the discharged sewage, and the spatial coordinates of the discharge point; S3. Call the two-dimensional advection-diffusion model, and calculate the spatiotemporal distribution of the diffusion concentration field of pollutants in the receiving water body after the discharge of domestic sewage from the ship, based on the ship's navigation status data, the background concentration of pollutants in the water quality data of the receiving water body around the ship, and the emission source term parameters, and output the emission impact prediction results. S4. Based on the collected ship location information, water quality data of the receiving water body around the ship, and the emission impact prediction results output in step S3, determine the compliance of the ship's sewage discharge behavior and generate a discharge decision instruction; the compliance determination specifically includes: Based on the vessel's location information, determine whether the current sea area meets the emission area requirements and generate a first judgment result; Based on the background concentration of pollutants in the water quality data of the receiving water body around the ship, determine whether the receiving water body has environmental capacity, and generate a second judgment result; Based on the emission impact prediction results, determine whether the pollutant concentration after emission can be diluted to below the safety threshold within a preset time, and generate a third judgment result; When the first, second, and third judgment results are all affirmative, a decision instruction to allow emissions is generated; when any judgment result is negative, a decision instruction to suspend emissions is generated. S5. Based on the emission decision command generated in step S4, execute the corresponding control operation and output prompt information to the ship operator; wherein, when the decision command is to allow emission, automatically control the emission equipment to turn on, allowing the discharge of domestic sewage; when the decision command is to suspend emission, prohibit the emission equipment from turning on, and output emission suggestion information to the ship operator, the emission suggestion information including but not limited to delaying emission, adjusting speed, reducing emission pump flow, or changing the emission area.

Claims

1. A ship wastewater discharge control system based on a water quality sensing and diffusion model, characterized in that: include: The AIS data acquisition module is used to obtain the ship's position, speed above ground, heading, and timestamp in real time. information; The water quality sensing module is installed below the waterline of the ship or at the seagate intake to detect the background concentration of pollutants in the receiving water around the ship in real time. The discharge equipment monitoring module is used to monitor the operating status of the ship's sewage discharge equipment and generate corresponding status signals when the discharge equipment is turned on or off. The pollution impact module has a built-in two-dimensional advection-diffusion model, which is used to analyze the flight speed data provided by the AIS data acquisition module and the status information provided by the emission equipment monitoring module. Based on the background concentration of pollutants detected by the water quality sensing module, the diffusion concentration field distribution of pollutants after the discharge of ship sewage is calculated, and the emission impact prediction results are output; wherein, the advection velocity component in the two-dimensional advection-diffusion model is coupled with the ship speed data. The decision instruction generation module is connected to the AIS data acquisition module, water quality sensing module, and pollution impact module, respectively, and is used to generate emission decision instructions that allow or suspend emissions based on the ship's location, background concentration of pollutants, and emission impact prediction results.

2. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 1, characterized in that: The AIS data acquisition module specifically includes: The AIS signal receiving unit is used to connect with the ship's AIS equipment and receive AIS data packets in real time. The data parsing unit, connected to the AIS signal receiving unit, is used to parse data according to the AIS data protocol. The AIS data message extracts the ship's latitude and longitude position, speed over land, heading, and timestamp information; The location compliance judgment interface unit, connected to the data parsing unit, is used to determine the latitude and longitude location. Information is sent to the regional compliance judgment unit of the decision instruction generation module; The speed and heading output interface unit, connected to the data parsing unit, is used to convert the ground speed into... The heading information is sent to the pollution impact module as a coupling input parameter to couple with the advection velocity component in the two-dimensional advection-diffusion model; The time synchronization unit, connected to the data parsing unit, is used to extract the timestamp information and perform time synchronization calibration on the latitude and longitude position, ground speed, and heading.

3. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 2, characterized in that: The pollution impact module specifically includes: The model storage unit is used to store and initialize the two-dimensional advection-diffusion model; The parameter coupling unit is connected to the speed and heading output interface unit and is used to acquire the ship's ground speed and heading data, and to couple the advection velocity component with the speed data according to a preset coupling relationship, and output the coupled advection velocity parameter. The source term generation unit is connected to the emission equipment monitoring module and is used to receive the status signal output by the emission equipment, and determine the start and end time, emission location and emission intensity of the emission behavior according to the status signal to generate pollutant source term parameters. The background concentration input unit is connected to the water quality sensing module and is used to obtain the background concentration of pollutants in the receiving water around the ship, and to use the background concentration of pollutants as the boundary condition of the two-dimensional advection-diffusion model. The numerical solution unit is connected to the model storage unit, parameter coupling unit, source term generation unit and background concentration input unit respectively. It is used to solve the two-dimensional advection-diffusion model based on the coupled advection velocity parameters, pollutant source term parameters and pollutant background concentration, and calculate the spatiotemporal distribution of the diffusion concentration field of pollutants in the receiving water body after the discharge of ship sewage. The prediction result output unit, connected to the numerical solution unit, is used to output the calculated spatiotemporal distribution of the diffusion concentration field as the emission impact prediction result to the decision instruction generation module.

4. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 2, characterized in that: The coupled advection velocity parameter is specifically expressed as follows: ;in, Indicates the ship's speed; Indicates the ship's heading angle; Indicates the influence coefficient of speed; and Both represent the advection velocity component; The pollutant source term parameters are specifically represented as follows: ;in, This indicates the amount of wastewater discharged per unit of time. Indicates the initial concentration of pollutants in the discharged wastewater; Indicates the spatial coordinates of the initial emission point; This represents the Dirac function.

5. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 3, characterized in that: The two-dimensional advection-diffusion model is specifically represented as follows: in, This represents the background concentration of pollutants at time t in two-dimensional space (x, y); and These represent the diffusion coefficients of water in the horizontal and vertical directions, respectively.

6. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 1, characterized in that: The background concentration of pollutants specifically includes one or more of the following: total nitrogen concentration, total phosphorus concentration, chemical oxygen demand, suspended solids content, and coliform bacteria concentration.

7. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 1 or 4, characterized in that: The emission equipment monitoring module specifically includes: The signal acquisition unit is used to acquire the on or off status of the emission equipment in real time and generate corresponding status signals. The storage capacity monitoring module is used to monitor the storage capacity of the wastewater storage tank and generate data on changes in storage capacity. The emission behavior identification module is connected to the signal acquisition unit and the storage monitoring unit, respectively, and is used to identify the start and end time of the emission behavior based on the status signal and the storage change data, and to calculate the amount of sewage discharged per unit time.

8. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 6, characterized in that: The decision instruction generation module specifically includes: The regional compliance judgment unit, connected to the AIS data acquisition module, is used to determine whether the current sea area meets the emission area requirements based on the ship's position, and to generate a first judgment result; An environmental capacity judgment unit, connected to the water quality sensing module, is used to judge whether the receiving water body has environmental capacity based on the background concentration of pollutants in the receiving water body around the ship, and to generate a second judgment result. The diffusion impact judgment unit, connected to the pollution discharge impact module, is used to judge whether the concentration of pollutants after discharge can be diluted to below the safety threshold within a preset time based on the emission impact prediction result, and generate a third judgment result; The integrated decision-making unit is connected to the regional compliance judgment unit, the environmental capacity judgment unit, and the diffusion impact judgment unit, respectively, and is used to generate emission decision instructions based on the first judgment result, the second judgment result, and the third judgment result. Specifically, when the first judgment result, the second judgment result, and the third judgment result are all yes, the integrated decision-making unit generates a decision instruction to allow emissions; when any judgment result is no, the integrated decision-making unit generates a decision instruction to suspend emissions.

9. The ship wastewater discharge control system based on a water quality sensing and diffusion model according to claim 1, characterized in that: The system also includes an emission data storage module for storing navigation status data, water quality monitoring data, emission equipment operation status data, and emission impact prediction results during the discharge of ship sewage.

10. A method for controlling ship wastewater discharge based on a water quality sensing and diffusion model, implemented by the system described in any one of claims 1 to 8, the method comprising the following steps: S1. Real-time collection of ship navigation status data, water quality data of the receiving water body around the ship, and operational status data of discharge equipment; among which... The ship navigation status data includes at least the ship's latitude and longitude position, speed over land, heading, and timestamp information, which is acquired through the AIS data acquisition module; the emission equipment operation status data includes the on or off status of the emission equipment, which is acquired through the emission equipment monitoring module. S2. Identify the discharge behavior of shipboard domestic sewage based on the operating status data of the discharge equipment, and determine the discharge source parameters; when the discharge equipment is detected to be turned on, it is determined that the discharge behavior has started, the discharge start time and discharge location are recorded, and the sewage discharge volume is obtained based on the liquid level change of the sewage storage tank; when the discharge equipment is detected to be turned off, it is determined that the discharge behavior has ended; the discharge source parameters include the sewage discharge volume per unit time, the initial concentration of pollutants in the discharged sewage, and the spatial coordinates of the discharge point; S3. Call the two-dimensional advection-diffusion model, and calculate the spatiotemporal distribution of the diffusion concentration field of pollutants in the receiving water body after the discharge of domestic sewage from the ship, based on the ship's navigation status data, the background concentration of pollutants in the water quality data of the receiving water body around the ship, and the emission source term parameters, and output the emission impact prediction results. S4. Based on the collected ship location information, water quality data of the receiving water body around the ship, and the emission impact prediction results output in step S3, determine the compliance of the ship's sewage discharge behavior and generate a discharge decision instruction; the compliance determination specifically includes: Based on the vessel's location information, determine whether the current sea area meets the emission area requirements and generate a first judgment result; Based on the background concentration of pollutants in the water quality data of the receiving water body around the ship, determine whether the receiving water body has environmental capacity, and generate a second judgment result; Based on the emission impact prediction results, determine whether the pollutant concentration after emission can be diluted to below the safety threshold within a preset time, and generate a third judgment result; When the first, second, and third judgment results are all affirmative, a decision instruction to allow emissions is generated; when any judgment result is negative, a decision instruction to suspend emissions is generated. S5. Based on the emission decision command generated in step S4, execute the corresponding control operations and output prompt information to the ship operator; wherein, when the decision command is to allow emission, automatically control the emission equipment to turn on, allowing the discharge of domestic sewage; when the decision command is to suspend emission, prohibit the emission equipment from turning on, and output emission suggestion information to the ship operator.

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