Case Background: Procurement Requirement of a Municipal Sanitation Department in Guilin City. Located in northeastern Guangxi Province, Guilin features a subtropical monsoon climate—characterized by hot, rainy summers and high humidity—posing stringent requirements on specialized vehicles’ corrosion resistance, sealing component durability, and high-load operational capability. In 2025, a municipal sanitation department in Guilin planned to procure a batch of National VI emission-compliant sewage treatment vehicles to enhance urban sewage treatment efficiency. Following multiple rounds of tendering, three units of Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as 'Chengli') National VI Dongfeng 3308 mm wheelbase sewage treatment vehicles were successfully delivered and are now operating stably across Guilin’s urban and surrounding areas. The procurement project budget was controlled within approximately RMB 904,000 (based on publicly available tender information), with an estimated unit price of around RMB 282,000 (per local procurement practice). Vehicles were required to comply with National VI emission standards and possess functions including sewage suction, sewage transfer, preliminary filtration, and cleaning—while maintaining stable performance during high-frequency operations in the rainy season. Pre-Tender Preparation for Government Procurement: From Requirements to Technical Specifications. Prior to issuing the tender notice, the procuring entity typically conducts market research and requirement analysis. For humid–hot environments like Guilin, key considerations included: Corrosion-Resistant Coating: Tank body and chassis must feature corrosion-resistant coatings to prevent rust caused by high humidity. Sealing Component Durability: Seals for sewage pumps and piping must withstand high temperatures and corrosion, ensuring long-term leak-free operation in humid–hot conditions. High-Load Performance: Due to frequent rainy-season operations, vehicles must sustain continuous suction and transfer tasks; engines and pump systems must remain stable under prolonged load. Prior to bidding, Chengli proactively provided technical proposals and assisted the procuring entity in drafting the technical specification document. For example, addressing Guilin’s climatic conditions, Chengli recommended the Dongfeng 3308 mm wheelbase chassis (e.g., model CLW5040TQZD6), a 4 mm-thick tank fabricated from Q235B steel with an internal epoxy resin anti-corrosion coating, and imported fluororubber seals to extend service life in humid–hot environments. How to Draft a Technical Specification Document: Key Parameters and Real-World Case Comparison. The technical specification document is the core of the tender file, clearly defining vehicle performance, configuration, and service requirements. Below are actual technical parameters used in the Guilin case, benchmarked against Chengli’s product offerings: Technical Parameter | Procuring Entity’s Requirement | Chengli’s Proposed Solution (e.g., CLW5070GSSD6 series) Emission Standard | National VI | National VI, equipped with DPF + SCR aftertreatment system Tank Capacity | ≥3 m³ | 3.5 m³; tank fabricated from Q235B steel with internal anti-corrosion coating Suction Pump Flow Rate | ≥50 m³/h | 60 m³/h; vacuum-assisted pump with suction lift ≥8 m Seal Material | Corrosion- and heat-resistant | Imported fluororubber, rated for -20°C to 120°C Rainy-Season Operational Capability | Continuous operation ≥8 hours | Dual-pump system enabling full-load engine operation Corrosion Protection | Anti-corrosion treatment for tank and chassis | Epoxy resin coating + electrophoretic paint on chassis After-Sales Service | Nationwide chassis warranty; lifetime superstructure service | Dongfeng chassis covered under nationwide warranty; Chengli superstructure covered by lifetime service As shown in the table, Chengli’s proposal fully meets—and in certain aspects exceeds—the procuring entity’s req