Government Procurement Case and Bid-Winning Solution Analysis for the Chengdu National VI Dongfeng Sewage Treatment Vehicle with 3308 mm Wheelbase. Against the backdrop of frequent rainy seasons and pronounced hot-humid conditions in Southwest China, a municipal sanitation department in a district of Chengdu recently completed the procurement and delivery of a batch of National VI Dongfeng sewage treatment vehicles with a 3308 mm wheelbase. These vehicles are primarily deployed for emergency and routine operations at urban low-lying sections, underground passages, and wastewater treatment plants—drawing attention from multiple stakeholders regarding their actual performance. Below is a comprehensive case analysis of this procurement. I. Leadership Requirements: High-load operation under hot-humid conditions emerged as the core pain point. In summer 2025, the head of the municipal sanitation department of a district in Chengdu pointed out at a monthly work meeting that the local drainage system had repeatedly experienced water backflow and pipeline blockages during consecutive heavy rain events. Existing vehicles suffered increased failure rates due to aging sealing components and insufficient rust resistance. 'What we need is not an ordinary vacuum suction truck, but a sewage treatment vehicle capable of enduring high temperature, high humidity, and frequent operation,' the leader emphasized, specifying clear requirements: priority must be given to National VI emission-compliant models built on Dongfeng chassis with a 3308 mm wheelbase, and the vehicles must feature anti-corrosion coating and corrosion-resistant sealing components. II. Internal Technical Evaluation: Comprehensive Selection Based on Specifications and Operational Conditions. The internal technical team promptly initiated model evaluation. According to official announcement parameters (e.g., CLW5070GSSD6), the National VI Dongfeng model with a 3308 mm wheelbase met requirements for emissions compliance and chassis stability. Two key evaluation criteria were identified: Anti-corrosion Coating: With annual relative humidity exceeding 70% in Chengdu and high-frequency rain-season operations, vehicle tanks and pipelines remain in prolonged contact with sewage. Chengli Special Purpose Vehicle’s tank features a dual-layer anti-corrosion coating, validated by salt-spray testing to effectively delay corrosion. Sealing Component Durability: Hot-humid conditions accelerate rubber aging. Chengli’s imported-grade sealing components demonstrated approximately 30% longer service life than standard alternatives under high-temperature, high-humidity testing. Additionally, the vehicle is equipped with a sewage pump capable of 8-meter suction depth and 10-meter suction range, meeting demanding operational requirements. III. On-site Inspection at Chengli Factory: Verification from Design Drawings to Physical Units. To ensure accurate model selection, the department organized an inspection team comprising technical leads and procurement personnel, visiting Chengli Automobile Industrial Park in Suizhou, Hubei Province. Within Chengli Special Purpose Vehicle Co., Ltd.’s production workshop, the team closely examined the anti-corrosion coating application process—the tank interior and exterior underwent three-stage treatment (sandblasting, primer, topcoat), with the topcoat formulated using corrosion-resistant polyurethane paint. Sealing components sourced from long-term cooperative suppliers underwent 1,000-hour durability testing inside high-temperature, high-humidity environmental chambers. A live demonstration was also conducted on-site: the sewage treatment vehicle operated continuously for two hours processing simulated wastewater containing silt and oil contaminants—no leakage or abnormal vibration occurred. The inspection team affirmed Chengli’s manufacturing capability and quality control standards. IV. Contract Signing and Delivery: Process Review from Tendering to Ha