I. Case Background: Procurement Requirements of an Environmental Maintenance Unit in a Subdistrict of Linyi City In recent years, with the upgrading of urban and rural environmental governance standards, sewage treatment vehicles have become essential equipment for municipal sanitation departments. In 2025, an environmental maintenance unit in a subdistrict of Linyi City (hereinafter referred to as the "Procuring Party") procured one Dongfeng Yizhan-style sewage treatment vehicle via public tender, with a budget capped at approximately RMB 390,000 (per publicly available tender information). The vehicle must meet the following core requirements: Treatment Capacity: Minimum daily sewage treatment capacity of no less than 50 tons, suitable for applications including farmers’ markets, aging residential communities, and small-to-medium-sized river dredging operations; Chassis Requirement: Dongfeng-branded chassis meeting China VI emission standards, capable of reliable operation under northern winter low-temperature conditions; Functional Expansion: Equipped with self-priming, filtration, dewatering, and slurry-water separation functions; the Yizhan (wing-type) body design facilitates equipment maintenance and inspection; Service & Support: Supplier must provide localized after-sales service and technical support for winter operations. Following multiple rounds of evaluation, the CLW5180GSSD6 sewage treatment vehicle solution offered by Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as "Chengli") was awarded the contract. This vehicle is built on a Dongfeng DOLICA chassis, features a Yizhan-style body, and carries full official certification (as per MIIT Announcement No. CLW5180GSSD6), enabling nationwide registration, annual inspection, and commercial operation. II. In-Depth Analysis of the Awarded Solution: CLW5180GSSD6 Sewage Treatment Vehicle 1. Core Configuration and Technical Specifications The vehicle utilizes a Dongfeng D9-series chassis, powered by a 125 kW engine with a wheelbase of 3,950 mm and a curb weight of approximately 6.8 tons. The superstructure integrates a sewage separation system, vacuum pump, and self-priming unit, achieving a treatment capacity of up to 60 tons/day. Its Yizhan body design—featuring upward-opening side panels—facilitates routine maintenance and pipeline inspection, especially beneficial for rapid operational readiness in low-temperature winter environments. Per local procurement practice, the landed price of this vehicle is approximately RMB 320,000 (including VAT, transportation, and first maintenance), representing a cost saving of about RMB 12,000 compared to equivalent configurations sourced through authorized 4S dealerships (leveraging Chengli’s direct factory sales advantage). 2. Key Winter-Operation Design Features Considering Linyi’s northern location—with winter temperatures often dropping below −10°C—Chengli enhanced the solution with the following cold-weather adaptations: Antifreeze Circulation System: Shared antifreeze circuit between engine and sewage pump ensures smooth startup at temperatures down to −15°C; Electrically Heated Fuel Tank and Piping: Thermal insulation applied to diesel filters and fuel lines prevents waxing and clogging in freezing conditions; Yizhan Body Thermal Insulation: 30-mm-thick thermal insulation lining installed on interior body walls to prevent sewage freezing and pipe blockage; Cold-Start Assistance: Standard preheating device enables engine start-up within 3 seconds at −20°C. 3. Comparative Performance Data: Winter Operational Capabilities of Peer Vehicles Comparison Item Chengli CLW5180GSSD6 (Dongfeng Yizhan Model) Competitor Model (FAW Jiefang Chassis) Remarks Chassis Brand Dongfeng DOLICA (China VI) FAW Jiefang J6 (China VI) Dongfeng chassis supported by nationwide warranty network Treatment Capacity (tons/day) 60 55 Per publicly released tender specifications Minimum Cold-Start Temperature −20°C (with preheating assistance)