A combined sewer system and control method

Abstract

The application provides a combined drainage system and a control method. The combined drainage system comprises a preliminary flow discarding well chamber system, a valve assembly and a control system. The preliminary flow discarding well chamber system comprises a flow discarding well, a valve assembly and a control system. The flow discarding well is provided with a water inlet for connecting a water inlet pipe, a first water outlet for connecting a first water collecting pool, a second water outlet for connecting a second water collecting pool and a flow discarding outlet for connecting a flow discarding pipe. The valve assembly comprises a first valve, a second valve and a third valve. The first valve is arranged at the first water outlet. The second valve is arranged at the second water outlet. The third valve is arranged at the flow discarding outlet. The control system is connected with the first valve, the second valve and the third valve respectively, and is used for controlling the opening or closing of the valves. The preliminary flow discarding well chamber system utilizes a PLC controller, thereby realizing the classified discharge and recovery of water under different working conditions, and improving the operation efficiency and safety of the flow discarding well.

Description

Technical Field

[0001] This invention belongs to the field of engineering drainage technology, and specifically relates to an initial diversion well system and control method for a combined sewer system. Background Technology

[0002] In existing technologies, combined sewer systems and separate sewer systems are the two main types of urban drainage systems. A combined sewer system uses the same set of pipe systems to collect and transport sewage and rainwater. Its advantages include low cost, simple construction, and convenient maintenance, but it also has disadvantages such as difficulty in sewage treatment, complex system management, and poor rainwater utilization. A separate sewer system, on the other hand, uses different pipe systems to collect and transport sewage and rainwater separately. This system is beneficial for sewage treatment, facilitates rainwater utilization, and has good environmental benefits, but it is more expensive, more difficult to construct, and more difficult to manage.

[0003] An initial runoff well is a facility with a specific structure that discharges the more polluted rainwater at the beginning of rainfall and collects only the relatively clean rainwater in the later stages. It works by temporarily storing the initial rainwater through volume or infiltration, while the later rainwater flows into the municipal stormwater network or rainwater collection system through bypass pipes.

[0004] Currently, the application scenarios of initial diversion facilities in engineering are only for single rainwater drainage systems. The existing initial diversion facilities themselves do not meet the requirements of combined sewer system and recycling functions. Moreover, under the existing combined sewer system, water resources are treated as sewage. This simple treatment method not only increases the total amount of sewage to be treated, leading to increased sewage treatment costs, but also prevents water resources from being classified and recycled, resulting in water waste. Summary of the Invention

[0005] To address several problems existing in the prior art, this invention provides an initial diversion well system and control method for a combined sewer system.

[0006] The technical solution of the present invention is as follows:

[0007] An initial diversion chamber system for a combined sewer system includes:

[0008] The diversion well has a well body structure, which is provided with an inlet for connecting to the inlet pipe, a first outlet for connecting to the first collection tank, a second outlet for connecting to the second collection tank, and a diversion outlet for connecting to the diversion pipe.

[0009] A valve assembly includes a first valve, a second valve, and a third valve; the first valve is disposed at a first drain outlet and is used to control the opening and closing of the first drain outlet; the second valve is disposed at a second drain outlet and is used to control the opening and closing of the second drain outlet; the third valve is disposed at a diversion outlet and is used to control the opening and closing of the diversion outlet.

[0010] A control system is connected to the first valve, the second valve, and the third valve respectively, and is used to control the opening or closing of each valve.

[0011] Furthermore, it also includes a monitoring unit, which includes at least a rainfall monitor for monitoring rainfall events and a flow meter for monitoring runoff flow, and the monitoring unit is communicatively connected to the control system;

[0012] The control system controls the opening and closing of the first valve, the second valve, and the third valve based on the rainfall signal and runoff flow signal obtained by the monitoring unit.

[0013] Furthermore, the control system is specifically configured as follows:

[0014] When the acquired rainfall signal indicates no rain, the first valve is opened, and the second and third valves are closed.

[0015] When the acquired rainfall signal indicates rain and the acquired runoff flow rate is less than a preset threshold, the third valve is controlled to open, and the first and second valves are controlled to close.

[0016] When the acquired rainfall signal indicates rain, and the acquired runoff flow rate is greater than or equal to the preset threshold, the second valve is controlled to open, and the first and third valves are controlled to close.

[0017] Furthermore, the preset threshold is the initial runoff threshold, which is proportional to the product of the initial runoff thickness and the catchment area.

[0018] Furthermore, the bottom elevation of the inlet is higher than the top elevation of the diversion outlet and the second outlet, and the top elevation of the first outlet is lower than the bottom elevation of the diversion outlet and the second outlet.

[0019] Furthermore, the bottom of the wastewater well is provided with a water-absorbing trough for settling impurities, and the bottom surface of the water-absorbing trough is a slope.

[0020] Furthermore, it also includes:

[0021] A sludge monitoring unit is installed inside the wastewater well and is communicatively connected to the control system for monitoring the amount of sludge inside the well.

[0022] A cleaning mechanism, installed inside the wastewater well and connected in communication with the control system, is used to clean the silt inside the well under the control of the control system.

[0023] Furthermore, the cleaning mechanism includes:

[0024] A stirrer is installed at the bottom of the wastewater well to agitate the settled sludge.

[0025] A mud pump, installed at the bottom of the wastewater well, is used to pump out the agitated mud-water mixture.

[0026] A control method for the aforementioned initial diversion chamber system includes the following steps:

[0027] S1: Acquire rainfall and runoff flow signals;

[0028] S2: When the acquired rainfall signal is no rain, control the first valve to open and control the second and third valves to close, controlling the water flow to the first collection tank;

[0029] S3: When the acquired rainfall signal indicates rain and the acquired runoff flow is less than a preset threshold, control the third valve to open and control the first valve and the second valve to close, controlling the water to flow to the sewage network through the diversion pipe;

[0030] S4: When the acquired rainfall signal indicates rain and the acquired runoff flow rate is greater than or equal to the preset threshold, control the second valve to open and control the first and third valves to close, controlling the water flow to the second collection tank.

[0031] Furthermore, as mentioned above, it also includes:

[0032] S5: The sludge volume signal in the wastewater well is obtained in real time through the sludge monitoring unit;

[0033] S6: When the sludge volume signal exceeds a preset threshold, the cleaning mechanism is activated to clean the sludge in the well;

[0034] S7: When the sludge volume signal falls below the preset threshold, the cleaning mechanism is turned off.

[0035] The beneficial effects of this invention are as follows:

[0036] This invention discloses an initial diversion well system and control method for a combined sewer system. By adding drainage branch pipes, diversion pipes, and matching valves to the diversion well, it achieves classified discharge and recycling of water resources under different operating conditions in a combined sewer system. This solves the problem that separate sewer systems are difficult to implement due to site constraints, and reduces engineering construction costs. Furthermore, based on automation control and sensing technology, and utilizing a programmable logic controller (PLC), it realizes automated control of diversion well drainage under different operating conditions and automatic cleaning of the diversion well, improving the efficiency and safety of diversion well operation and management. Attached Figure Description

[0037] Figure 1 This is a top view schematic diagram of the internal structure of the wastewater well of the present invention;

[0038] Figure 2 This is a cross-sectional schematic diagram of the 1-1 side of the wastewater diversion well of the present invention;

[0039] Figure 3 This is a schematic cross-sectional view of the wastewater well 2-2 of the present invention;

[0040] Figure 4 This is a schematic diagram of the PLC control system for the wastewater diversion well of the present invention.

[0041] In the diagram: 11. Inlet pipe; 12. Second drain pipe; 13. Diversion pipe; 14. First drain pipe; 21. First collection tank; 22. Second collection tank; 3. Suction tank; 31. Agitator; 32. Sludge pump; 41. Third valve; 42. First valve; 43. Second valve; 5. Manhole cover; 6. Maintenance ladder; 7. Power supply; 8. Diversion well cleaning subsystem; 81. Sludge sensor; 9. Diversion well drainage subsystem; 91. Rainfall monitor; 92. Electromagnetic flow meter; 10. PLC control cabinet. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0043] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected" and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a direct connection, or the interaction relationship between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] The following describes the initial diversion well chamber system and control method of a combined sewer system according to the present invention.

[0045] refer to Figures 1 to 4 The initial diversion chamber system of a combined sewer system provided in this embodiment mainly includes a diversion well, valve assembly, and control system.

[0046] refer to Figures 1 to 3 In one embodiment, the diversion well has a well body structure with a hollow interior. The well body structure is provided with an inlet for connecting to the inlet pipe 11, a first outlet for connecting to the first collection pool 21, a second outlet for connecting to the second collection pool 22, and a diversion outlet for connecting to the diversion pipe 13.

[0047] The valve assembly includes a first valve 42, a second valve 43, and a third valve 41; the first valve 42 is located at the first drain outlet and is used to control the opening and closing of the first drain outlet; the second valve 43 is located at the second drain outlet and is used to control the opening and closing of the second drain outlet; the third valve 41 is located at the diversion outlet and is used to control the opening and closing of the diversion outlet.

[0048] The control system is connected to the first valve 42, the second valve 43 and the third valve 41 respectively, and is used to control the opening or closing of each valve.

[0049] Specifically, the diversion well is an underground structure connecting multiple types of drainage pipe networks. It consists of a well body structure, a well cover 5, an inlet pipe 11, a first drainage pipe 14, a second drainage pipe 12, a diversion pipe 13, an inspection ladder 6, and a water suction trough 3.

[0050] The well body structure is the main underground structure of the wastewater diversion well, and is constructed using cast-in-place concrete or precast concrete. The inlet pipe 11 is a pre-reserved hole in the well body structure, connecting the combined sewer inlet pipe 11 to the wastewater diversion well. The first drain pipe 14 connects the wastewater diversion well to the first collection tank 21, and the second drain pipe 12 connects to the second collection tank 22. The wastewater diversion pipe 13 connects the wastewater diversion well to the plant's wastewater drainage network. The first collection tank 21 collects water from the wastewater diversion well during non-rainy periods, and the second collection tank 22 collects water from the wastewater diversion well during the later stages of rainfall.

[0051] Each valve is used to control the opening and closing of each drain outlet and diversion outlet, and all of them are communicatively connected to the control system to receive control commands from the control system.

[0052] The control system is a programmable logic controller (PLC) system, which is the automatic control system for the diversion well system. It includes a hardware system and a software system. The hardware system consists of a PLC control cabinet 10, a diversion well drainage subsystem 9, a diversion well cleaning subsystem 8, and a power supply 7; the software system includes programming software and running programs.

[0053] The drainage control subsystem controls the opening and closing of electrically controlled valves at each drainage outlet of the wastewater well, enabling the classified discharge and recycling of water resources within the well. It consists of PLC components, electrically controlled valves, a rainfall monitor 91, an electromagnetic flowmeter 92, and connecting links.

[0054] The well chamber cleaning subsystem is used for automatic cleaning of sludge at the bottom of the wastewater well. It consists of PLC components, a vortex mixer, a sludge pump 32, a sludge sensor 81, and connecting links.

[0055] Therefore, the wastewater diversion well, based on control system and sensor technology, achieves automated operation and maintenance of the system. This automated design greatly improves the operating efficiency and safety reliability of the drainage system, avoiding the tedious work and safety concerns of regular manual dredging.

[0056] In one embodiment, a monitoring unit is further included, which includes at least a rainfall monitor for monitoring rainfall events and a flow meter for monitoring runoff flow.

[0057] Specifically, the rainfall detector is used to monitor rainfall and transmit the rainfall information to the PLC control center. The electromagnetic flowmeter 92 is used to calculate the water flow rate and transmit the flow rate information to the upstream unit. The control system controls the opening and closing of the first valve 42, the second valve 43, and the third valve 41 based on the rainfall signal and runoff flow signal obtained by the monitoring unit.

[0058] The classified discharge and recycling of diverted well water includes three types of water under different operating conditions:

[0059] Non-rainy operating conditions: The wastewater in the overflow well mainly consists of production wastewater and material yard washing water, which can be recycled for production use.

[0060] Initial rain conditions: The water source for the diversion well includes initial rainwater, production wastewater, and site road washing water. Due to the mixed water quality and high cost of recycling and treatment, a diversion scheme is adopted to discharge the water into the plant's sewage network.

[0061] Mid-to-late stage of rain: The water source of the diversion well includes rainwater and production wastewater in the mid-to-late stage of rain. This is different from the early stage of rain. At this time, the proportion of rainwater in the mixed water increases and the water quality is significantly improved. This part of the well can be treated by simple physical methods and used for site washing and greening maintenance.

[0062] Therefore, the control system is specifically configured as follows:

[0063] When the acquired rainfall signal indicates no rain, it is a non-rainy operating condition. The first valve 42 is opened, and the second valve 43 and the third valve 41 are closed.

[0064] When the acquired rainfall signal indicates rain and the acquired runoff flow is less than a preset threshold, it is the initial rainy season. The third valve 41 is opened, and the first valve 42 and the second valve 43 are closed.

[0065] When the acquired rainfall signal indicates rain and the acquired runoff flow is greater than or equal to the preset threshold, it is a mid-to-late stage of rainfall. The second valve 43 is opened, and the first valve 42 and the third valve 41 are closed.

[0066] This embodiment divides combined sewer systems into different operating conditions, each corresponding to a different flow path. This design enables refined classification and management of combined stormwater and sewage at different times.

[0067] In one embodiment, the initial and later stages of rainfall are defined by using the initial runoff value W as the boundary. An initial runoff threshold, i.e., the expected threshold [W], is determined by calculation. [W] is directly proportional to the product of the initial runoff thickness δ and the catchment area F, as shown in the formula:

[0068] [W]=10×δ×F

[0069] The initial runoff thickness δ is determined based on the specific site conditions, taking into account the measured CODCr (chemical oxygen demand), SS (suspended solids), and color of rainwater collected from the ground surface.

[0070] The actual initial runoff value W is measured by the electromagnetic flowmeter 92. When W < [W], it is the initial stage of rainfall; when W ≥ [W], it is the middle and late stage of rainfall.

[0071] In one embodiment, the elevation relationship of the inlet pipe 11, the diversion pipe 13, the first drain pipe 14, and the second drain pipe 12 is designed to meet the basic requirements of graded water recovery and discharge under various operating conditions. The inlet pipe 11 has the highest elevation, with its bottom elevation higher than the top elevations of the drain pipes and the diversion pipe 13; the top elevation of the first drain pipe 14 is lower than the bottom elevations of the diversion pipe 13 and the second drain pipe 12. This elevation design ensures that daily wastewater preferentially enters the first collection tank 21, and that the basic functions of the system are still guaranteed even if the control system fails.

[0072] In one embodiment, the bottom of the diversion well is provided with a water suction tank 3 for settling impurities in the combined water. The water suction tank 3 can be integrally formed with the diversion well or formed through secondary structural construction. The bottom of the diversion well is provided with a certain slope.

[0073] Specifically, the wastewater diversion well is also equipped with a sludge monitoring unit and a cleaning mechanism. The sludge monitoring unit is a sludge sensor 81, and the cleaning mechanism includes a stirrer 31 and a sludge pump 32, both of which are communicatively connected to the control system. The sludge sensor 81 is used to monitor the amount of sludge in the well. The stirrer 31 and the sludge pump 32 are located at the bottom of the wastewater diversion well. The stirrer 31 is used to agitate the settled sludge, and the sludge pump 32 is used to pump out the agitated mud-water mixture.

[0074] Among them, the sludge sensor 81 transmits the detected sludge interface signal to the PLC control center, and the PLC control center then processes the information and issues a response command.

[0075] This invention also provides a control method for the above-mentioned initial diversion well chamber system, including steps S1-S4, and steps S5-S7 for subsequent well chamber cleaning.

[0076] S1: Acquire rainfall and runoff flow signals.

[0077] Specifically, rainfall signals and runoff flow signals are acquired through rainfall monitor 91 and electromagnetic flow meter 92, and the signals are transmitted to the PLC control center.

[0078] S2: When the acquired rainfall signal is no rain, control the first valve 42 to open and control the second valve 43 and the third valve 41 to close, controlling the water flow to the first water collection tank 21.

[0079] S3: When the acquired rainfall signal indicates rain and the acquired runoff flow is less than a preset threshold, control the third valve 41 to open and control the first valve 42 and the second valve 43 to close, controlling the water to flow to the sewage network through the diversion pipe 13.

[0080] S4: When the acquired rainfall signal indicates rain and the acquired runoff flow rate is greater than or equal to the preset threshold, control the second valve 43 to open and control the first valve 42 and the third valve 41 to close, controlling the water flow to the second collection tank 22.

[0081] Specifically, by analyzing the signals from the rainfall monitor 91 and the electromagnetic flowmeter 92, the first valve 42, the second valve 43, and the third valve 41 are opened respectively, while the other two valves are closed. This design enables refined classification and management of combined sewer overflows at different times.

[0082] S5: The sludge volume signal in the wastewater well is obtained in real time through the sludge monitoring unit.

[0083] Specifically, the sludge volume signal is acquired through the sludge sensor 81 and transmitted to the PLC control center.

[0084] S6: When the sludge volume signal exceeds the preset threshold, the cleaning mechanism is activated to clean the sludge in the well.

[0085] S7: When the sludge volume signal falls below the preset threshold, the cleaning mechanism is turned off.

[0086] Specifically, by processing the signal from the sludge sensor 81, the PLC control center issues a response command after processing the information. When the monitored sludge interface value is less than the preset threshold, the PLC does not issue a cleaning command, and the relevant mechanical equipment is in standby mode. When the monitored sludge interface value is greater than or equal to the preset threshold, the PLC issues a cleaning command. At this time, the agitator and sludge pump 32 are started. During the cleaning process, the sludge sensor 81 sequentially feeds back the sludge interface value to the PLC. When the monitored value is less than the set threshold, the PLC issues a stop working command.

[0087] Therefore, the aforementioned initial diversion chamber system and control method have at least the following advantages:

[0088] 1. By adding drainage branch pipes, diversion pipe 13 and matching valves to the diversion well, the classified discharge and recycling of water resources under different working conditions under the combined sewer system can be realized, which solves the problem that the site conditions limit the implementation of the separate drainage system and reduces the construction cost of the project.

[0089] 2. Based on automation control and sensing technology, and using programmable logic controllers (PLCs), the system realizes automated control of drainage and automatic cleaning of wastewater wells under different operating conditions, thereby improving the efficiency and safety of wastewater well operation and management.

[0090] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. An initial diversion chamber system for a combined sewer system, characterized in that, include: The diversion well has a well body structure, which is provided with an inlet for connecting to the inlet pipe, a first outlet for connecting to the first collection tank, a second outlet for connecting to the second collection tank, and a diversion outlet for connecting to the diversion pipe. A valve assembly includes a first valve, a second valve, and a third valve; the first valve is disposed at a first drain outlet and is used to control the opening and closing of the first drain outlet; the second valve is disposed at a second drain outlet and is used to control the opening and closing of the second drain outlet; the third valve is disposed at a diversion outlet and is used to control the opening and closing of the diversion outlet. A control system is connected to the first valve, the second valve, and the third valve respectively, and is used to control the opening or closing of each valve.

2. The initial diversion chamber system for a combined sewer system according to claim 1, characterized in that, It also includes a monitoring unit, which includes at least a rainfall monitor for monitoring rainfall events and a flow meter for monitoring runoff flow, and the monitoring unit is communicatively connected to the control system; The control system controls the opening and closing of the first valve, the second valve, and the third valve based on the rainfall signal and runoff flow signal obtained by the monitoring unit.

3. The initial diversion chamber system for a combined sewer system according to claim 2, characterized in that, The control system is specifically configured as follows: When the acquired rainfall signal indicates no rain, the first valve is opened, and the second and third valves are closed. When the acquired rainfall signal indicates rain and the acquired runoff flow rate is less than a preset threshold, the third valve is controlled to open, and the first and second valves are controlled to close. When the acquired rainfall signal indicates rain, and the acquired runoff flow rate is greater than or equal to the preset threshold, the second valve is controlled to open, and the first and third valves are controlled to close.

4. The initial diversion chamber system for a combined sewer system according to claim 3, characterized in that, The preset threshold is the initial runoff threshold, which is proportional to the product of the initial runoff thickness and the catchment area.

5. The initial diversion chamber system for a combined sewer system according to claim 1, characterized in that, The bottom elevation of the inlet is higher than the top elevation of the diversion outlet and the second outlet, and the top elevation of the first outlet is lower than the bottom elevation of the diversion outlet and the second outlet.

6. The initial diversion chamber system for a combined sewer system according to claim 1, characterized in that, The bottom of the wastewater well is equipped with a water-absorbing trough for settling impurities, and the bottom surface of the water-absorbing trough is a slope.

7. The initial diversion chamber system for a combined sewer system according to claim 6, characterized in that, Also includes: A sludge monitoring unit is installed inside the wastewater well and is communicatively connected to the control system for monitoring the amount of sludge inside the well. A cleaning mechanism, installed inside the wastewater well and connected in communication with the control system, is used to clean the silt inside the well under the control of the control system.

8. The initial diversion chamber system for a combined sewer system according to claim 7, characterized in that, The cleaning mechanism includes: A stirrer is installed at the bottom of the wastewater well to agitate the settled sludge. A mud pump, installed at the bottom of the wastewater well, is used to pump out the agitated mud-water mixture.

9. A control method for an initial diversion chamber system according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Acquire rainfall and runoff flow signals; S2: When the acquired rainfall signal is no rain, control the first valve to open and control the second and third valves to close, controlling the water flow to the first collection tank; S3: When the acquired rainfall signal indicates rain and the acquired runoff flow is less than a preset threshold, control the third valve to open and control the first and second valves to close, controlling the water to flow to the sewage network through the diversion pipe; S4: When the acquired rainfall signal indicates rain and the acquired runoff flow rate is greater than or equal to the preset threshold, control the second valve to open and control the first and third valves to close, controlling the water flow to the second collection tank.

10. The control method for the initial diversion chamber system according to claim 9, characterized in that, The system according to claim 7 further includes: S5: The sludge volume signal in the wastewater well is obtained in real time through the sludge monitoring unit; S6: When the sludge volume signal exceeds a preset threshold, the cleaning mechanism is activated to clean the sludge in the well; S7: When the sludge volume signal falls below the preset threshold, the cleaning mechanism is turned off.

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