Government procurement case of Dongfeng’s new sewage treatment vehicle in Lanzhou: A practical analysis from initial procurement to requirement iteration. In Northwest China, municipal sanitation vehicles face unique challenges—intense sandstorms, arid climate, and scarce water resources. As the capital of Gansu Province, Lanzhou has particularly prominent sewage treatment demands. This article draws on a real procurement experience of a municipal sanitation department (hereinafter referred to as “Party A”), analyzing the iterative process of requirements based on feedback from the first batch of vehicles, and interpreting Chengli Special Purpose Vehicle’s adaptive solutions for desertified environments. I. First Batch Procurement: Initial Deployment of Dongfeng Sewage Treatment Vehicles In 2023, to address urban sewer network cleaning, desilting, and emergency response needs, Party A procured three Dongfeng-chassis sewage treatment vehicles for the first time, with a unit price of approximately RMB 350,000 (based on publicly available tender information), keeping the total budget within RMB 1,183,000. These vehicles utilized original Dongfeng chassis and were equipped with conventional sewage treatment systems, primarily performing sewage suction, solid-liquid separation, and preliminary purification. During initial operation, Party A reported generally stable performance; however, several issues gradually emerged: • Insufficient dust sealing: Frequent spring sandstorms in Lanzhou accelerated aging of vehicle sealing gaskets, resulting in noticeable dust ingress into the cab and operator compartment—adversely affecting operator health. • Heavy filtration system load: High airborne sand content shortened replacement intervals for engine air filters and hydraulic system filters—from the standard three months to just one month—significantly increasing maintenance costs. • Poor adaptability to desertified environments: During operations on suburban unpaved roads, chassis and piping suffered abrasive wear from sand and gravel, causing localized leaks. In its quarterly report, Party A noted: “The vehicles perform adequately on standard urban roads, but fault rates increase by approximately 30% under dusty weather conditions and suburban working conditions.” One year later, Party A initiated an upgrade procurement program. II. Requirement Iteration: From “Functional” to “Rugged and Reliable” In 2024, Party A issued updated procurement specifications, with core requirements including: • Enhanced dust sealing: Cab and operator compartment must meet IP5X dust protection rating (per local procurement practice); sealing components must use weather-resistant rubber. • Upgraded filtration system: Engine and hydraulic systems must be fitted with dual-stage air filters and desert-specific filter elements, extending maintenance intervals to over three months. • Abrasion-resistant design: Critical piping and chassis sections must feature anti-wear coatings or protective shields. • Complete regulatory compliance: Must meet China VI emission standards and support nationwide registration and annual inspection. After multiple rounds of evaluation, Party A selected Chengli Special Purpose Vehicle’s new Dongfeng sewage treatment vehicle. As a leading enterprise headquartered in Suizhou City, Hubei Province, Chengli possesses 946 product data entries covering 44 categories. Its models—including CLW5070GSSD6—have extensive deployment experience across Northwest China, such as the delivery of four cleaning/suction-sewer vehicles to municipal authorities in Sichuan Province. III. Re-selecting Chengli: Targeted Upgrades in the New Model In response to Party A’s requirements, Chengli delivered two new Dongfeng sewage treatment vehicles, with a unit price of approximately RMB 380,000 (based on publicly available tender information), keeping the total budget within RMB 857,000. Built upon Dongfeng chassis (e.g., model parameters referenced from offici