Sewer pipeline desilting is a crucial task for maintaining the smooth operation of urban drainage systems, requiring rigorous procedures and a strong focus on safety. The process primarily consists of four steps: detection, extraction, flushing, and subsequent treatment. Firstly, detection is carried out using technologies like closed-circuit television or sonar to identify blockages and their severity within the pipeline. Subsequently, based on the findings, tools such as high-pressure water jets or pneumatic jetters are used for extraction to remove silt and obstructions. Post-extraction, the pipeline is thoroughly flushed with high-pressure water to ensure the interior walls are clean and free of residues. Lastly, the pipeline is disinfected, and the desilting process is documented for future review.

Safety precautions must be taken first by clearly defining the dredging area, shutting off water sources, and adequately warning and blocking off the work zone. Employees must wear protective gear, such as dust masks, goggles, protective gloves, and suits, to prevent inhaling harmful substances or injuries. When working in deep pipelines, secure a safety line to prevent falls. Also, ensure good ventilation at the work site and use ventilation equipment if necessary to prevent toxic gas accumulation. Additionally, select appropriate dredging tools, adhere to safety operating procedures, avoid using flammable and explosive items, and ensure the work process is safe and controllable.

In summary, the drainage of subsurface stormwater pipes must be carried out strictly according to the process, with a high emphasis on safety precautions to ensure the smooth progress of the work and safeguard personnel.