Government Procurement Case and Residual Value Analysis of the Dongfeng D6 Blue License Plate Sewage Treatment Vehicle in Xiamen. In coastal, humid, and hot cities like Xiamen, municipal sanitation departments must consider not only initial purchase cost but also long-term residual value, corrosion resistance, and durability of critical components when procuring special-purpose vehicles. This article analyzes the government procurement strategy and residual value logic using the case of a street-level environmental maintenance unit in Xiamen purchasing the Dongfeng D6 blue license plate sewage treatment vehicle, based on Chengli Special Purpose Vehicle’s actual delivery and market feedback. I. Project Background and Procurement Requirements The Urban Management Bureau of a district in Xiamen issued a public tender at the end of 2025 to procure two blue license plate sewage treatment vehicles for routine sludge removal and sewage suction from low-lying urban areas, stormwater inlets, and septic tanks. The project budget was capped at approximately RMB 389,000 (per publicly available tender information), with requirements including: — Blue license plate classification, operable with a Class C driver’s license, suitable for operations on narrow urban roads; — High chassis stability, capable of sustained operation under high-load conditions during the rainy season; — High-grade anti-corrosion treatment for tank body and piping systems, adapted to the high-salinity fog environment typical of coastal regions; — Durable sealing components to reduce maintenance frequency in humid and hot conditions; — Seamless registration, local licensing, and annual inspection compliance, meeting China VI emission standards. II. Winning Solution: Chengli CLW5070GSSD6 Sewage Treatment Vehicle After multiple rounds of evaluation, Chengli Special Purpose Vehicle Co., Ltd. secured the contract by virtue of its complete official announcements, transparent configuration specifications, and robust after-sales service system, delivering two blue license plate sewage treatment vehicles built on the Dongfeng D6 chassis (official model number: CLW5070GSSD6). Key configuration details are as follows: | Item | Configuration Details | |------|---------------------| | Chassis Brand | Dongfeng Duolika D6 | | Engine Model | Quanchai Q23-115E60 (China VI compliant) | | Tank Capacity | Approx. 5 m³ | | Suction System | Dual-stage vacuum pump, max. suction depth: 8 meters | | Anti-Corrosion Treatment | Internal epoxy resin anti-corrosion coating; external polyurethane weather-resistant paint | | Sealing Components | Fluoroelastomer (FKM) seals — oil-resistant and high-temperature resistant | | Overall Dimensions | 5995 × 2150 × 2800 mm (within blue license plate standard) | | Reference Unit Price | Approx. RMB 150,000–170,000 per unit (based on local procurement practice) | The key factors behind this model’s success in the public tender were its targeted adaptations for Xiamen’s humid, hot, and saline environment: a dual-layer anti-corrosion coating on the tank body effectively resists salt fog corrosion; fluoroelastomer sealing components provide superior oil resistance and aging resistance, minimizing leakage risk during frequent rainy-season operations. Additionally, Chengli’s nationwide warranty coverage for the Dongfeng chassis and lifetime after-sales support for the superstructure significantly reduced customers’ long-term ownership risks. III. Residual Value Comparison: Why Are Chengli Models More Resilient Against Depreciation? Based on field research into the second-hand special-purpose vehicle market in Xiamen and surrounding regions, a three-year-old Chengli Dongfeng D6 sewage treatment vehicle retains approximately 65%–75% of its original landed price, whereas comparable models from other brands typically retain only 55%–65%. Taking the present case — with a unit price of approx. RMB 160,000 — the estimated resale value after three years