Government Procurement Case and Bid-Winning Solution Interpretation for the New Dongfeng Sewage Treatment Truck in Nanyang I. Case Background: Procurement Requirements of a Municipal Sanitation Department in Nanyang In winter 2025, a municipal sanitation department in Nanyang City, Henan Province, issued a public tender to procure two units of the new Dongfeng sewage treatment trucks for urban and rural sewage pipeline renovation and emergency response tasks. Per local procurement practice, the budget was capped at approximately RMB 559,000 per unit, with mandatory requirements including mobile sewage suction/drainage, solid-liquid separation, emergency treatment capability, and cold-weather starting performance. After multiple rounds of evaluation, Chengli Special Automobile Co., Ltd. (hereinafter referred to as “Chengli”) secured the contract based on its mature chassis integration, complete special vehicle type approval (Announcement), and robust after-sales support, ultimately delivering two Dongfeng-chassis sewage treatment trucks. The procured vehicles are primarily intended for cleaning aging residential septic tanks, emergency sewage suction/drainage from rivers, and remediation of black-and-odorous water bodies in rural areas—thus demanding high cold-weather adaptability, operational efficiency, and system reliability. Chengli’s proposal featured the Dongfeng DOLICA chassis, paired with its self-developed vacuum pump and solid-liquid separation system, ensuring reliable operation down to -10°C. II. Vehicle Configuration and Technical Parameter Interpretation Based on the Ministry of Industry and Information Technology (MIIT) Announcement parameters (model reference: CLW5070GSSD6 series), the delivered sewage treatment trucks feature the following key specifications: Chassis Model: Dongfeng DOLICA (China VI emission standard), wheelbase 3,308 mm, engine power 95 kW—compliant with urban driving restrictions and environmental regulations. Tank Capacity: Sewage tank ≈ 3.5 m³; clean water tank ≈ 1.5 m³—enabling continuous operation for over 2 hours. Suction/Discharge System: Equipped with a two-stage vacuum pump; maximum suction rate ≥ 80 L/min; maximum suction depth ≥ 7 m—suitable for deep wells and underground pipelines. Separation System: Centrifugal solid-liquid separation technology; separation efficiency ≥ 85%; residual solids content in effluent ≤ 5%—meeting local discharge standards. Cold-Weather Adaptability: Standard features include cold-start assistance, fuel-line heating system, and insulated piping—ensuring normal startup and operation at temperatures as low as -15°C. Parameter Item Dongfeng DOLICA (CLW5070GSSD6) Competing Models (Reference) Chassis Brand Dongfeng (Nationwide Warranty) Other Brands Engine Power 95 kW 82–90 kW Total Tank Capacity 5 m³ 4–4.5 m³ Maximum Suction Depth 7 m 5–6 m Separation Efficiency ≥ 85% 70–80% Cold-Start Capability -15°C (Standard) -10°C (Optional) Reference Unit Price Approx. RMB 240,000–260,000 (per publicly disclosed tender data) Approx. RMB 260,000–300,000 III. Winter-Operation Structural Design: Key Maintenance Practices and Cold-Start Recommendations for Northern Regions 3.1 Key Winter Maintenance Practices for Northern Regions Winter temperatures in the Nanyang region may drop below -10°C. Improper maintenance of sewage treatment trucks can lead to frozen or cracked pipelines, seized vacuum pumps, and battery discharge. Upon delivery, Chengli’s technical team provided a comprehensive maintenance manual highlighting the following critical points: Antifreeze Replacement: Use -35°C antifreeze, replaced every two years to prevent freezing of the cooling system. Fuel-Line Insulation: Install heating tapes on diesel filters and fuel lines to prevent wax precipitation at low temperatures. Vacuum Pump Maintenance: Drain condensate and inspect seals after each operation.