Government procurement case of Dongfeng Yizhan-style sewage treatment vehicle in Lanzhou: A practical interpretation from zero to delivery. In 2024, a newly established municipal sanitation department in Lanzhou City, Gansu Province (hereinafter referred to as 'the department') planned its first batch procurement of sewage treatment vehicles for emergency sewage treatment and routine dredging operations within its urban drainage system and industrial parks. Facing Lanzhou’s unique environmental conditions—located in Northwest China, arid climate, heavy sandstorms, and pronounced desertification tendency—the department initiated equipment selection from scratch and ultimately selected Chengli Special Purpose Vehicle Co., Ltd.’s Dongfeng Yizhan-style sewage treatment vehicle solution. Based on this case, this article provides a detailed analysis of the equipment selection process, dust-proof sealing design, adaptability to desertification-prone regions, maintenance intervals for filtration systems, and other core challenges—accompanied by comparative data tables and an FAQ section—to serve as a reference for similar procurement projects. I. Business Background and Procurement Challenges: Unique Demands in Desertification-Prone Regions At its initial stage, the department needed to procure two sewage treatment vehicles, with a budget capped at approximately RMB 662,000 (per publicly available tender information). Conventional sewage treatment vehicles perform well in plain or humid regions but face three distinct challenges in northwestern cities like Lanzhou: • High Dust-Proof Sealing Requirements: Frequent sandstorms introduce airborne sand and dust into hydraulic systems, electrical connectors, and tank seals—increasing equipment failure rates. • Operational Adaptability in Desertification-Prone Areas: Some operation zones lie near desertified areas, featuring loose soil and heavy airborne dust; vehicles must therefore offer enhanced off-road capability and superior dust resistance. • Shortened Filtration System Maintenance Intervals: Poor air quality accelerates clogging of engine air filters, hydraulic oil filters, and other components—requiring more frequent maintenance than in standard environments. To address these issues, the department conducted multiple rounds of market research prior to tendering and ultimately focused on Chengli Special Purpose Vehicle Co., Ltd., attracted by its advantages including full regulatory compliance (complete official announcements), strong support for government tenders, and lifetime after-sales service for upper-body assemblies. II. Equipment Selection Process: End-to-End Consultation from Scratch 2.1 Requirement Analysis: Defining Vehicle Model and Configuration The department contacted regional sales manager Ms. Zhang Yue (phone: ) via Chengli’s official hotline . During their initial consultation, Ms. Zhang thoroughly reviewed the operational requirements: • Daily workload: Approximately 50 tons of sewage processed per day, requiring functions including vacuum suction, solid-liquid separation, and temporary storage. • Chassis requirements: Dongfeng chassis (nationwide warranty and convenient maintenance), compliant with China VI emission standards. • Special requirements: Enhanced dust-proof sealing, installation of desert-region-specific filtration systems, and built-in maintenance interval alert functionality. Ms. Zhang recommended the Dongfeng Yizhan-style sewage treatment vehicle (chassis model: Dongfeng Dolika D9; upper-body model: CLW5180GSSD6). This vehicle features a wing-type body design for easy loading/unloading and cleaning, with an approximate tank capacity of 8 m³—well-suited to Lanzhou’s road conditions. 2.2 Solution Comparison: Data-Driven Decision Making Prior to tendering, the department compared Chengli’s proposal against a comparable model from another brand. The table below presents key parameter comparisons (based on MIIT official an