I. Project Background and Procurement Requirements: In the summer of 2025, a municipal sanitation department in Hangzhou issued a public tender to procure a batch of blue license plate sewage treatment vehicles for river and sewer network maintenance within its jurisdiction. The project budget was capped at approximately RMB 418,000, requiring vehicles capable of sewage suction, solid-liquid separation, and preliminary purification—while also meeting conditions such as C1 driver’s license operability and unrestricted urban road access. According to publicly released tender information, Chengli Special Purpose Vehicle Co., Ltd. delivered a sewage treatment vehicle built on the Dongfeng D6 chassis, priced at around RMB 350,000, becoming one of the winning bids for this procurement. Hangzhou, located in the Jiangnan water town region, experiences frequent rainfall and high humidity during summer and autumn, leading to common issues such as blockages and overflows in sewer pipelines. Therefore, the procuring party explicitly required enhanced anti-corrosion coatings, durable sealing components suitable for hot-humid environments, and proven reliability under high-frequency operation during rainy seasons. Chengli’s solution—based on the Dongfeng D6 blue license plate chassis (model CLW5070GSSD6)—fully complies with these stringent requirements both in official technical specifications and real-world application. II. Analysis of Chengli’s Winning Bid Factors: Based on the tender announcement and industry experience, Chengli secured this contract primarily due to the following factors: Direct Manufacturer Advantage: As a manufacturer, Chengli participated directly in the bidding process. Public tender data indicates that, for identical configurations, purchasing directly from Chengli saves approximately RMB 8,000–15,000 compared to procurement via 4S dealerships—offering stronger price competitiveness. Comprehensive Official Announcement & Hassle-Free Registration: The Dongfeng D6 blue license plate sewage treatment vehicle carries a complete MIIT (Ministry of Industry and Information Technology) announcement (e.g., CLW5070GSSD6), enabling seamless nationwide registration, annual inspection, and commercial operation permit issuance—addressing the buyer’s compliance concerns. Nationwide Chassis Warranty: Dongfeng chassis are covered by the original manufacturer’s nationwide warranty; Chengli’s superstructure offers lifetime after-sales support, with spare parts shipped directly within 24 hours. For cities like Hangzhou—where rapid repair response is critical—this service system significantly reduces long-term operational and maintenance risks. Localized Service Capability: Chengli has completed multiple delivery projects across Zhejiang Province, including two compact garbage trucks supplied to a property management company in Zhejiang, accumulating valuable experience in maintaining vehicles under southeastern coastal climatic conditions. Anti-Corrosion and Sealing Process: To address Hangzhou’s hot-humid climate, Chengli applied reinforced anti-corrosion coating to the sewage tank and piping, and selected high-humidity-resistant sealing components—ensuring minimal leakage or rust even during high-frequency rainy-season operations. Customer Feedback: According to relevant personnel from the municipal sanitation department, during the first rainy season after commissioning, the vehicle operated continuously for 15 days under high-frequency duty without any critical component failures. Sealing components remained stable, and no peeling was observed on the anti-corrosion coating. These vehicles remain in normal daily service with excellent operational performance. III. Technical Highlights and Parameter Overview: The Dongfeng D6 blue license plate sewage treatment vehicle delivered for this project (reference model CLW5070GSSD6) features technical design optimizations tailored specifically for hot-humid regions: Chassis Configuration: D