Case Background: In December 2025, a municipal sanitation department in a district of Zhangzhou City, Fujian Province, launched a public tender for the procurement of a batch of blue license plate, 5-cubic-meter sludge suction trucks to support urban stormwater pipeline and riverbed desilting operations. Located on the southern coast of Fujian, Zhangzhou features a subtropical monsoon humid climate, with an average annual rainfall of approximately 1,500 mm. Rainfall is highly concentrated during the rainy season, and typhoons occur frequently—leading to rapid sediment accumulation in drainage networks and requiring high-frequency cleaning. The project required vehicles with superior maneuverability, strong corrosion resistance, and stable sealing performance under hot-humid conditions to sustain year-round high-intensity operations. According to publicly released tender information, the procurement budget was capped at approximately RMB 345,000, with plans to acquire two blue license plate, 5-cubic-meter sludge suction trucks. After comprehensive evaluation, the Dongfeng single-cab chassis sludge suction truck solution offered by Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as "Chengli SPV") was selected. Based on model CLW5070GSSD6, this solution incorporated targeted configuration optimizations specifically for Zhangzhou’s hot-humid environment. Selection Analysis: Advantages of the Dongfeng Single-Cab Chassis and Blue License Plate 5-cubic-meter Sludge Suction Truck The Dongfeng single-cab sludge suction truck (model CLW5070GSSD6) supplied by Chengli SPV utilizes a Dongfeng light-duty chassis with an axle base of approximately 3,308 mm and an overall vehicle length not exceeding 6 meters—meeting the C-class driver’s license requirement for blue license plates and facilitating operation on narrow urban roads. The chassis is equipped with a China VI-compliant diesel engine delivering a maximum power output of approximately 85 kW, providing ample torque to handle complex working conditions such as sludge and sandstone extraction. In response to Zhangzhou’s high humidity, frequent rainfall, and severe salt fog corrosion, Chengli SPV implemented three key enhancements to the superstructure: • Corrosion-Resistant Coating Upgrade: The tank body and piping are coated with an epoxy resin + polyurethane composite coating, with a minimum thickness of ≥200 μm. Salt spray testing confirmed no rust formation after 1,000 hours—extending service life by 50% compared to conventional coatings. • Enhanced Sealing Component Durability: All hydraulic system seals are made from fluororubber, offering an operational temperature range of −20°C to +200°C, excellent hydrolysis resistance, and outstanding anti-aging performance—ensuring long-term stable operation under high-temperature, high-humidity conditions. • High-Load Operation Adaptation: To accommodate the high operational frequency and extended continuous working hours typical during the rainy season, a hydraulic oil cooler and independent cooling circulation system were installed to prevent excessive oil temperature rise and consequent seal failure. The unit price of this solution is approximately RMB 125,000 (per publicly available tender data), with the tax-inclusive delivered price falling within the approved budget. Chengli SPV provides nationwide Dongfeng chassis warranty coverage and lifetime after-sales service for the superstructure, including 24-hour direct shipment of spare parts—significantly reducing post-purchase maintenance risks. Actual Delivery and Operational Performance In January 2026, two Chengli Dongfeng single-cab sludge suction trucks were officially delivered to the municipal sanitation department of the district in Zhangzhou and immediately deployed for pre-Spring Festival stormwater network desilting operations. During actual use, customers reported the following key performance indicators: • Uptime Rate: Over a continuous 30-day oper