1. Background: Sewage Treatment Requirements of a Municipal Sanitation Department in Zhengzhou. In winter 2025, a municipal sanitation department in Zhengzhou planned to procure a batch of new Dongfeng-chassis sewage treatment vehicles to address emergency issues including sewer network blockages, river pollution, and domestic wastewater treatment within its jurisdiction. The department had previously used sanitation vehicles from Chengli Special Automobile Co., Ltd., with positive feedback. This procurement budget was controlled at approximately RMB 339,000–451,000 per unit, requiring high maneuverability, strong suction capacity, and stable low-temperature operation performance in winter. Based on publicly available tender information, Chengli Special Automobile ultimately won the bid and delivered three Dongfeng-chassis-based sewage treatment vehicles. 2. Winning Solution Overview: New Dongfeng Chassis + Chengli Bodywork. The winning sewage treatment vehicle model primarily references the official parameters of the Chengli CLW5180GSSD6 series. It adopts a new Dongfeng National VI chassis equipped with a Cummins engine delivering a maximum power output of 180 hp. The bodywork—designed independently by Chengli Special Automobile—integrates sewage recirculation filtration, solid-liquid separation, and high-pressure cleaning functions. Key specifications are as follows: Chassis Model: Dongfeng Tianjin DFH1180EX8, wheelbase 4,500 mm, compliant with National VI emission standards. Sewage Tank Capacity: Approximately 8 m³, constructed from corrosion-resistant carbon steel. Core Functions: Equipped with a high-power vacuum pump (suction depth up to 8 meters), a high-pressure cleaning pump (pressure up to 16 MPa), and an automatic discharge system. Winter Adaptability: All piping systems feature electric heating insulation; the sewage tank exterior is wrapped with thermal insulation material, ensuring normal operation at ambient temperatures as low as -15°C. Price: Approximately RMB 350,000 per unit (tax-inclusive landed price, per public tender data), saving about RMB 12,000 per unit compared to 4S dealership channels. Customer Feedback: The department head stated: “Chengli’s solution demonstrates exceptional reliability in cold-start performance and freeze protection. We specifically evaluated the electric heating system and confirmed it ensures uninterrupted winter operations.” 3. Operational Analysis for Winter Conditions: Key Maintenance Practices and Cold-Start Recommendations for Northern Climates. Drawing from this case and considering typical northern winter climatic conditions, the following key operational recommendations are summarized: 3.1 Cold-Start Essentials Preheating System: When ambient temperature falls below -10°C, preheat the engine for 5–10 minutes before startup to ensure adequate oil lubrication. The Chengli CLW5180GSSD6 model comes standard with an intake air preheating device, significantly reducing startup time. Battery Maintenance: Battery capacity typically declines by ~30% in winter; regularly check electrolyte density and replace with low-temperature batteries if necessary. Fuel Selection: Use -20# or lower-grade diesel fuel to prevent waxing at low temperatures. 3.2 Freeze Protection Measures Piping Insulation: Install electric heating tapes and thermal insulation sleeves on sewage pipelines and valves to prevent freezing and blockage. Chengli offers these as optional accessories at approximately RMB 2,000 per set. Tank Freeze Prevention: Drain residual sewage from the tank immediately after operation to avoid freezing-induced expansion damage. Antifreeze Replacement: Replace antifreeze every two years, ensuring its freezing point is at least 10°C lower than the local minimum ambient temperature. 4. Comparative Data: Chengli Sewage Treatment Vehicle vs. Market Competitors. The table below compares the Chengli CLW5180GSS