Urban rainfall runoff pollution process control refers to the use of physical, chemical, biological, and management techniques to reduce the volume and pollution load of rainwater runoff after it enters the collection system (including combined sewer networks, separate rainwater pipes, and storage facilities), in order to achieve the goal of runoff pollution control. This process involves the control techniques used during the convergence, collection, and discharge (overflow) of rainwater runoff, including front-end control techniques for drainage networks, rainwater inlet technologies, diversion techniques, design and maintenance of drainage pipes, pollution control and purification strategies for overflow and initial rainwater pollution, as well as key purification technologies