I. Case Background: Cross-regional Replication from a City in Shanxi Province to Taiyuan City In 2025, a municipal sanitation department in Shanxi Province procured a batch of yellow-plate sewage treatment vehicles via public tender for emergency treatment of urban river and domestic wastewater. The project budget was capped at approximately RMB 900,000, resulting in the delivery of three sewage treatment vehicles built on Dongfeng chassis (model reference: CLW5070GSSD6), each priced at around RMB 260,000. These vehicles demonstrated stable suction and solid-liquid separation performance during actual operation—especially critical in northern China’s low-temperature winter conditions, where freeze-resistant startup and hydraulic system stability became key acceptance criteria. This successful implementation quickly attracted attention from neighboring provinces and cities. In early 2026, a district-level municipal sanitation department in Taiyuan City planned to replicate this solution to address chronic sewage discharge issues stemming from aging pipeline networks within its jurisdiction, intending to procure four identical yellow-plate sewage treatment vehicles. The procurement party specifically emphasized that the vehicles must operate reliably under Taiyuan’s extreme winter temperatures ranging from −20°C to −15°C, and must feature rapid cold-start capability, freeze-resistant hydraulic systems, and freeze-proof piping as core functional requirements. Consistent with local procurement practices, the total project budget was capped at approximately RMB 1,125,000. II. Core Challenges: Three Technical Pain Points Under Low-Temperature Winter Conditions During preliminary research for the Taiyuan project, the municipal sanitation department identified three critical requirements: • Freeze-Resistant Startup Performance: Conventional sewage treatment vehicles often fail to start in sub-zero environments due to frozen engines and hydraulic oil pumps—severely compromising emergency response times. • Low-Temperature Hydraulic Stability: At low temperatures, hydraulic oil viscosity increases significantly, potentially reducing pump efficiency, causing pipe blockages, or damaging seals. • Winter Maintenance Protocol: The buyer required the supplier to provide a clear winter maintenance manual—including antifreeze replacement intervals, recommended hydraulic oil grades, and overnight parking precautions. To address these pain points, the project team proposed a standardized solution based on Chengli Special Purpose Vehicle’s prior delivery experience in the Shanxi city and its service data across more than 500 municipal sanitation units nationwide. III. Standardized Solution: Model Configuration and Cold-Climate Adaptability Design Based on publicly available tender information, the Taiyuan project selected the Chengli CLW5180GSSD6 yellow-plate sewage treatment vehicle (technical specifications sourced from the MIIT database), equipped with a Dongfeng chassis and compliant with China VI emission standards. Key configurations include: • Freeze-Resistant Startup System: Equipped with electric preheating devices and auxiliary cold-start pumps, ensuring ≥95% single-attempt startup success rate at −25°C. • Hydraulic System: Uses low-temperature hydraulic oil (HV-32 grade), combined with an electrically heated oil tank and insulated piping to maintain operating oil temperature above −10°C. • Suction & Separation Module: Solid-liquid separation efficiency ≥85%; vacuum pump maximum suction depth: 8 meters—optimized for diverse working conditions associated with Taiyuan’s aging sewer networks. Comparison of Recommended Solutions: Taiyuan Project vs. Prior Shanxi City Deployment Project | Shanxi City (Delivered) | Taiyuan Project (Standardized Replication) Chassis Model | Dongfeng (reference CLW5070GSSD6) | Dongfeng (reference CLW5180GSSD6) Sewage Tank Capacity | ~5 m³ | ~8 m³ Freeze-Resistant Startup Method | Electric Preheating | Electr