Case Study: Bulk Procurement of Dongfeng Yizhan Wastewater Treatment Trucks by a Municipal Sanitation Department in Tianjin At the end of 2025, a municipal sanitation department in Tianjin procured a batch of wastewater treatment trucks via public tender to address rainwater-sewage pipeline renovation in aging residential communities and emergency drainage needs. Chengli Special Purpose Vehicle Co., Ltd. delivered six units of the Dongfeng Yizhan wastewater treatment truck (model CLW5180TWQD6), with a total contract value of approximately RMB 2.1 million (around RMB 350,000 per unit, based on publicly available tender information). These vehicles have been progressively deployed since January 2026 and have operated stably to date, demonstrating exceptional performance in severe cold conditions — becoming a key case supporting the department’s continued preference for Chengli-branded vehicles. I. Procurement Background and Requirement Analysis Tianjin is located on the North China Plain, where winter temperatures frequently drop below -15°C. Additionally, the city’s aging drainage networks suffer frequent blockages. Consequently, three core requirements were specified for the wastewater treatment trucks: • Cold-Start Capability: Vehicles must reliably start and operate at -20°C to prevent freezing of the engine or hydraulic system. • Low-Temperature Hydraulic Stability: Hydraulic components—including sewage pumps and vacuum pumps—must maintain stable output under low temperatures without efficiency loss due to increased oil viscosity. • Winter Maintenance Plan: A dedicated winter maintenance plan for northern regions was required, covering antifreeze coolant, engine preheating systems, and selection of winter-grade hydraulic oil. The department had previously used trucks from other brands; however, high winter failure rates and prolonged repair cycles significantly hampered emergency response efficiency. Therefore, this procurement placed special emphasis on the vehicle’s all-weather operational capability. II. Winning Solution Overview: Dongfeng Yizhan Wastewater Treatment Truck Chengli’s solution was built upon the Dongfeng Yizhan chassis (China VI emission standard) equipped with the CLW5180TWQD6 superstructure. Key highlights include: • Cold-Start System: Standard configuration includes a fuel heater and engine preheating device. When used with -35 diesel fuel, the vehicle achieves reliable startup within 5 minutes at -25°C. Field testing during the January 2026 cold snap (-18°C) in Tianjin confirmed a 100% successful startup rate. • Low-Temperature Hydraulic System: Features low-temperature hydraulic oil (pour point ≤ -40°C) and an electrically heated hydraulic oil tank, ensuring pump systems remain free of stalling or sluggishness in cold conditions. Sewage pump flow remains stable at ≥120 m³/h (as per manufacturer specifications), with no more than a 5% reduction in winter performance. • Winter Maintenance Package: Each vehicle is delivered with a comprehensive winter maintenance kit, including antifreeze coolant rated to -45°C, a hydraulic oil heating module, and a battery insulation cover. Also included is the 'Northern Winter Operation & Maintenance Manual'. Chengli’s after-sales team conducts quarterly on-site inspections; the chassis (Dongfeng OEM) is covered by nationwide warranty, while the superstructure receives lifetime service support and spare parts shipped within 24 hours. Additionally, the vehicle complies fully with official type-approval regulations, enabling normal registration and commercial operation permit issuance, meeting all local Tianjin licensing requirements. III. Comparative Data: Chengli Dongfeng Yizhan vs. Industry Standard Configurations Comparison Item Chengli Dongfeng Yizhan (CLW5180TWQD6) Industry Standard Configuration (Same Price Range) Cold-Start Temperature -25°C (with fuel heater + preheating device) -15°C (preheating device only) Hydraulic Oil Pour Point ≤ -40°C -25°C to -30°C