Government Procurement Case of Dongfeng’s New Sewage Treatment Vehicle in Dalian: A Comprehensive Analysis from Freeze Protection to Implementation. In winter 2025, a municipal sanitation department in Dalian (hereinafter referred to as the 'Dalian Project') procured three new sewage treatment vehicles based on Dongfeng chassis through public tender, for emergency sewage treatment in local industrial parks and residential areas. These vehicles operated reliably at -15°C, with no cold-start difficulties or hydraulic system failures—setting a benchmark for similar procurements across Northeast China. This article dissects the case step-by-step—from project background and technical solutions to cost comparison and standardized implementation—with special emphasis on cold-start performance, low-temperature hydraulic stability, and winter maintenance protocols—precisely the core concerns of northern procurement entities. I. Project Background and Requirements Analysis Located in a coastal city, the Dalian Project experiences winter temperatures frequently below -10°C. Moreover, industrial park wastewater contains high oil content and abundant impurities, imposing stringent requirements on the chassis and superstructure’s cold resistance and sealing performance. Per publicly released tender documents, the procuring entity explicitly specified the following requirements: • Cold-Start Capability: The vehicle must start within 5 seconds at -20°C, without battery discharge or diesel waxing due to low temperature. • Low-Temperature Hydraulic Stability: The hydraulic system must maintain stable operation—driving the sewage pump and agitator reliably—despite viscosity changes in hydraulic fluid at low temperatures, avoiding stalling or leakage. • Winter Maintenance Protocol: The supplier must provide a complete winter maintenance plan, including antifreeze replacement and heating system inspection. Chengli Special Purpose Vehicle Co., Ltd. (hereinafter 'Chengli') secured the contract by leveraging Dongfeng chassis’ nationwide warranty network and its lifetime after-sales service for superstructures, ultimately delivering three CLW5070GSSD6-model sewage treatment vehicles built on Dongfeng Dolika chassis (Note: CLW5070GSSD6 is the official announcement model number; the actual configuration was modified for sewage treatment). According to publicly available tender information, the total budget was controlled within approximately RMB 1.259 million, with an average unit price of around RMB 367,000. II. Technical Solution: Freeze Protection and Low-Temperature Adaptability To meet the Dalian Project’s specific requirements, Chengli’s engineering team implemented targeted modifications across three key areas: 1. Freeze-Protected Starting System The vehicle is equipped with Dongfeng’s original electric-heated diesel filter and a low-temperature battery (capacity ≥80 Ah), combined with anti-gelling additives for No. 0 diesel—ensuring immediate ignition without preheating at -20°C. During real-world testing, all three units—parked outdoors at Dalian Port for 48 hours—successfully started on the first attempt, with average startup time of ~3 seconds—well under the tender-specified 5-second threshold. 2. Low-Temperature Hydraulic Stability The hydraulic system uses synthetic low-temperature hydraulic oil (pour point: -40°C) and incorporates a 1.5 kW hydraulic oil heater. At -15°C operating conditions, oil temperature remained above 10°C, ensuring stable sewage pump flow at 30 m³/h (per CLW5070GSSD6 official announcement parameters), with no pressure fluctuations or abnormal noise. The agitator employs low-temperature-resistant sealing rings to prevent rubber hardening and subsequent leakage. 3. Winter Maintenance Protocol Chengli provides a 'Northern Winter Operation Manual' with each vehicle, covering: antifreeze freezing-point checks every 30 days (must be below -35°C); hydraulic oil filter element replacement every 500 operating hours.