Government procurement case of Dongfeng D6 blue license plate sewage treatment vehicle in Dali Bai Autonomous Prefecture: A solution transitioning from outdated equipment to efficient operations. I. Pain Points of Outdated Equipment and Surge in Procurement Demand. In early 2025, a municipal sanitation department in Dali Bai Autonomous Prefecture discovered during routine pipeline maintenance that several aging vacuum trucks and cleaning vehicles could no longer meet the growing demand for sewage treatment. Most of these units were procured prior to 2018 and exhibited the following critical issues: Non-compliant emissions: Older chassis mostly met China III or China IV emission standards, resulting in frequent traffic restrictions during Dali Prefecture’s increasingly stringent environmental inspections—and even facing mandatory scrapping risks. Low operational efficiency: Single-operation capacity was small (only 2–3 m³), and suction depth was insufficient to address deep urban pipeline blockages. High maintenance costs: Non-OEM modified components led to scarce spare parts, prolonged repair cycles, and annual maintenance expenses exceeding RMB 20,000 per unit—nearly 20% of the cost of a new vehicle. Registration difficulties: Some ‘backyard workshop’-modified models lacked complete official announcements, causing repeated failures during annual inspections and disrupting normal operational scheduling. To address these challenges, the department launched a new procurement initiative requiring vehicles to meet the following criteria: China VI emission standard; blue license plate operable with Class C driver’s license; tank capacity ≥3 m³; integrated vacuum-suction and high-pressure cleaning functionality; and total budget capped at approximately RMB 166,000. After extensive research, the department selected Chengli Special Purpose Vehicle Co., Ltd.’s Dongfeng D6 blue license plate sewage treatment vehicle. II. New Requirements Assessment and Chengli’s Solution Alignment. During the pre-tender phase, the procuring entity visited multiple local modification plants in Yunnan and found some manufacturers offering low bids but compromising on configuration—for instance, quoting RMB 128,000 for a ‘low-spec version’ lacking vacuum pump overflow protection devices and high-pressure cleaning guns, and using aged chassis inventory. Chengli Special Purpose Vehicle stood out due to the following advantages: Complete official announcement: The Dongfeng D6 chassis (model CLW5070GSSD6) is listed in the MIIT’s official vehicle announcement database, enabling nationwide registration, annual inspection, and commercial operation without complications. Transparent configuration: Chengli avoids ‘bundled pricing’; instead, it clearly specifies options—including tank material (carbon steel/stainless steel), vacuum pump brand (Yifeng/Shandong Shuanglun), and cleaning pressure—allowing clients to customize according to actual needs. Direct factory sales: Compared to 4S-channel pricing, same-specification vehicles are priced RMB 8,000–15,000 lower; production in Suizhou enables delivery of standard models within 7–15 days. Comprehensive after-sales support: Dongfeng chassis covered by nationwide warranty; Chengli superstructure supported by lifetime service; spare parts shipped directly within 24 hours—a critical advantage for remote-area users. Following local procurement practices, the department finalized an order for two Dongfeng D6 blue license plate sewage treatment vehicles, specifying a 3 m³ tank capacity, high-pressure cleaning system (≥16 MPa), and integrated overflow alarm device. III. Bid Award and Delivery: Key Milestones from Contract Signing to On-Site Deployment. Through open tendering, Chengli Special Purpose Vehicle secured the contract at a unit price of approximately RMB 138,000 (per publicly disclosed tender information), delivering two Dongfeng D6 blue license plate sewage treatment vehicles. Key milestones during delivery includ