Intelligent interception wells -- "dual-role" intelligent guardians for urban water environment improvement and flood control

　　 1. The Role of Intelligent Interception Wells in Improving Urban Water Environments and Managing Urban Waterlogging

　　The "State Council's General Office's Implementation Opinions on Strengthening Urban Waterlogging Management" (Guobanfa [2021] No. 11) clearly proposes that "rain and sewage separation should be promoted in a way that suits local conditions. Where conditions for renovation are not currently available, interception and storage methods should be used to reduce overflow pollution during the rainy season and improve rainwater drainage capacity." "Renovation of rainwater inlets and other water collection facilities should ensure that water collection and drainage capacities match. Renovation of rainwater outlets, interception wells, valves, and other auxiliary facilities should ensure that the elevations connect and that the flow cross-section meets requirements."

　　Intelligent interception wells are independently researched and patented products of our company. As an economical and effective tool for separating sewage and rainwater, intelligent interception wells not only play an important role in eliminating initial rainwater pollution and controlling overflow pollution from combined sewage and other surface water bodies, but also play a key role in collecting bottom sediment and pipe wall deposits after upstream pipe flushing, ensuring a normal flow cross-section in the pipes, and improving the rapid drainage capacity of accumulated water. They are indispensable "dual-role" smart guardians in improving urban water environments and managing waterlogging.  

　　 2. Layout, Structure, and Types of Intelligent Interception Wells

Layout of Intelligent Interception Wells (Inflow and Overflow in the Same Direction, Lateral Interception)

Structural Forms of Intelligent Interception Wells (Cast-in-place steel-reinforced concrete or prefabricated assembled resin concrete structure)

Type One Intelligent Interception Well: Wall-mounted flow-limiting gate + hydraulic/mechanical lower opening weir type

Type Two Intelligent Interception Well: Wall-mounted flow-limiting gate + gravity-free floating weir type

Type Three Intelligent Interception Well: Wall-mounted flow-limiting gate + weir plate adjustable weir type

Type Four Intelligent Interception Well: Wall-mounted flow-limiting gate + adjustable double-sided weir type

　　Taking an intelligent interception well on the bank of a river as an example, the interception well can be a cast-in-place steel-reinforced concrete structure, a prefabricated assembled steel-reinforced concrete structure, or an integrated plastic/fiberglass/resin concrete well.

　　According to the layout of the bank pipeline network, the interception well can adopt different layouts such as inflow and outflow in the same direction, lateral overflow, or inflow and overflow in the same direction, and lateral interception.

　　An energy dissipation drop is set at the inlet of the interception well's inflow pipe to reduce the kinetic energy of the inflow water and prevent the water level in the well from experiencing severe fluctuations due to the inflow velocity. A bottom slope and flow channel outlet are set at the bottom of the well, guiding the flow to the interception pipe outlet. This allows the suspended matter in the intercepted water to quickly flow towards the interception pipe, preventing low-velocity sedimentation in the well. A hydraulic or electric intelligent flow-limiting gate valve is set on the interception outlet side. According to the instructions of the "Source-Network-Plant" integrated system for "joint adjustment and drainage," and based on the water level in the well and the real-time prediction of the capacity of the initial rainwater treatment plant or the town wastewater treatment plant, the flow-limiting valve opening can be controlled to accurately limit the interception flow. On the overflow outlet side, based on the upstream service area, drainage system, drainage standards, and downstream water body capacity and water level changes, multiple types of overflow weirs can be set, such as hydraulic/mechanical lower opening weirs, hydraulic/mechanical weir plate adjustable weirs, gravity-free floating weirs, and manual/electric stainless steel adjustable double-sided weir gates. According to the "joint adjustment and drainage" instructions and the controlled water level in the well, the overflow weir can be quickly activated to discharge water, ensuring that no waterlogging occurs in the upstream service area. Depending on the type of overflow equipment, floating scum baffles, inclined self-cleaning horizontal screens, or vertically installed mechanical/hydraulically driven large overflow horizontal screens can be combined in front of the weir as multiple types of combined pollution control devices to intercept suspended matter in the overflow water and prevent water pollution. The intercepted suspended matter falls into the bottom slope of the well towards the flow channel and is transported to the end treatment plant through the interception pipe.   The intercepted suspended matter falls into the bottom slope of the well, flows toward the channel, and is transported to the end treatment plant via the interception pipe.  

　　 3. Water Environment Improvement Functions

　　 Sewage Interception and Piping in the Dry Season

　　During the dry season, the water level in the well is low, the overflow weir is raised to prevent backflow of river water, and the interception valve is opened for interception. Sewage mixed into rainwater pipelines in the separated sewage and rainwater system or dry-season sewage in combined sewage and rainwater systems can be completely intercepted and safely transported to the town wastewater treatment plant for centralized treatment.

　 　Initial Rainwater Interception and Piping

　　For separated sewage and rainwater systems, the initial rainwater introduced during rainfall is transported to the sewage interception trunk line set up on the bank through the interception pipe on the side of the well. Precise interception of initial rainwater can be achieved under two control scales: the initial rainfall period (5-10 minutes) or a certain initial rainfall depth (4-10 mm).

　　 Combined Sewage Interception

　　For combined sewage and rainwater systems, the designed interception multiple (n=2-5) of combined sewage can be safely achieved during rainfall.

　　 Overflow Water Scum Interception

　　With a floating scum baffle and a horizontal screen in front of the weir, the well can efficiently intercept scum and suspended matter in overflow rainwater or overflow combined sewage from separated or combined sewage and rainwater systems, preventing river pollution.

　　 Pipeline Sediment Collection and Transportation

　　In conjunction with the sediment-retaining and cleaning shields (gravity-free or hydraulic) set up along the upstream drainage pipes, especially the combined sewage and rainwater pipes, periodic cleaning of accumulated and deposited matter is performed, and it is transported to the end bank interception well. Through the interception facilities, it is finally transported to the wastewater treatment plant for centralized treatment via the interception trunk line. This prevents the "accumulative discharge" of pipeline sediment pollutants from polluting the river during the rainy season.  

　　 4. Urban Waterlogging Management Functions

　　 Preventing River Water Backflow, Ensuring Dry Pipes Before Rain, Improving Pipeline Retention, and Upgrading Management Standards

　　The interception well can adjust the height of the overflow weir to prevent backflow from urban drainage rivers. Before rain, the interception gate/valve can be opened to discharge the upstream service pipes and transport the discharged water into the sewage interception trunk line to the wastewater treatment plant for centralized treatment. The capacity for pipeline retention and storage of rainwater in the upstream drainage pipeline network can be increased. Without modifying the scale of existing pipelines, management measures can be used to improve drainage pipe discharge standards and reduce the risk of surface waterlogging.

　　 Removing Pipeline Sediment and Increasing Flow Cross-Section

　　Combined with the upstream drainage pipe's installed sediment interception and dredging shields (non-powered or hydraulic), periodically clean the accumulated and sedimentary materials in the upstream pipes, especially combined sewer pipes. Concentrate the cleaned sediment into the terminal interception well and discharge it through the interception main pipe to the terminal sewage treatment plant for centralized treatment. Removing sediments and sand around the pipes improves the pipe's cross-sectional area and drainage capacity.

　　 Remove rainwater sand and stones to prevent blockage.

　　During rainfall, as the intensity and volume of surface runoff increase, impurities such as sand, gravel, and clay on the ground will be washed into the rainwater drainage pipes. If not removed in time, this will block the pipes, affecting drainage capacity, rush into the river causing sediment accumulation and erosion of the riverbank ecological slope, impacting the river's flood control capacity and storage capacity. This interception well is equipped with energy dissipation humps/channels and sedimentation tanks, allowing the incoming water to dissipate energy and sediment in the well, concentrated in the sedimentation tank for cleaning, avoiding the above adverse effects.

　　 Quick-opening overflow weir gates for fast and safe drainage.

　　The overflow weir gates used in this interception well are of the quick-opening type, which can be quickly opened when a high water level alarm occurs in the well to drain the upstream water and prevent upstream waterlogging.  

　　 5. The Wisdom of Intelligent Interception Wells  

　　This interception well is fully compatible with the city's integrated management platform and can be quickly integrated into the city's smart management platform at any time, working together to achieve "one-screen city smart supervision".

　　This product integrates overflow weirs (bottom-opening weirs, non-powered pontoon weirs, weir plate adjustable weirs, double-sided weir gates, etc.), horizontal grate interception devices at the overflow location, and intelligent interception gates/valves. Equipment types and specifications are targeted based on the characteristics of the rainy season in China.

　　This interception well is equipped with a digital intelligent control cabinet. The well is equipped with various types of online instruments, including water level, flow velocity, flow rate online instruments, and self-recording rain gauges. The control cabinet monitors the operating status of each equipment, executes various automatic operation modes, and transmits instructions from the upper control center. It scientifically generates big data electronic reports, performs scientific analysis, and provides intelligent guidance for operation.

　　At the intelligent control cabinet online instrument and automatic control level, devices for online detection of overflow water volume and water quality during rainfall, statistics of the total volume and total amount of pollutants for each rainfall; statistics of the total volume and total amount of water quality of directly intercepted and piped water into the sewage pipe during the dry season and initial rainfall stages, etc., are added. Through a variety of adaptable methods such as advanced equipment contact switch opening degree positioning, liquid level ultrasonic or radar open channel flow measurement, liquid level cross-correlation or time difference flow measurement closed pipe flow measurement, not only is the original equipment on-site linkage and automatic control achieved, but all water quality, liquid level, flow velocity, and flow rate data are also statistically collected in real time and historically accumulated and analyzed, and uploaded to the upper control system to perform systematic analysis and optimization of the entire area, achieving systematic analysis and collaborative operation. The drawbacks of conventional interception wells operating independently in China are avoided. It truly achieves scientific, precise, and timely control of the smart operation of urban interception wells. Comprehensive operation statistical reports are generated to accumulate experience in safe, efficient, energy-saving, and low-consumption operation, forming a low-carbon emission optimization model. It also interfaces with the urban integrated management platform to form a unified management and coordinated operation pattern.  

　　 6. Company Classic Cases

　　The company wholeheartedly commits to factory-network-river-lake integrated water environment governance projects and actively responds to the national call. Combining its own advantages and experience, it participates in national water environment governance-related work. In 2020, our company won the bid for the Nanhu Water Environment Improvement Project - East and West Line Equipment Procurement and Installation Project for the initial rainwater collection system, and both the bottom-opening weir intelligent interception well and the pontoon weir intelligent interception well have been successfully applied in the Nanhu project.

　　Nanhu Water Environment Improvement Project - Overall layout diagram of the riverside intelligent interception well

　　 Nanhu Water Environment Improvement Project - Overall layout diagram of the riverside intelligent interception well