Government Procurement Case and Bid-Winning Solution Analysis for the EHY5045TWCE6 Sewage Treatment Vehicle (3308 mm Wheelbase) in Xi’an In winter 2022, a municipal sanitation department in Xi’an publicly procured one sewage treatment vehicle with a 3308 mm wheelbase, model EHY5045TWCE6, for emergency desilting and sewage treatment in urban drainage networks. The project budget was capped at approximately RMB 392,000, and the vehicle was ultimately delivered by Chengli Special Purpose Vehicle Co., Ltd. Based on this case and considering the operational characteristics of northern China’s winter conditions, this article provides an in-depth analysis of the procurement plan, equipment selection, and maintenance guidelines to serve as a reference for similar organizations. I. Project Background and Requirements Analysis Xi’an is located on the Guanzhong Plain, where winter temperatures frequently drop below −5°C. Moreover, many areas of the city’s drainage system are aging. Therefore, the sewage treatment vehicle must operate reliably under low-temperature, icy, and high-density sludge conditions. The client explicitly required: • Cold-weather engine start capability; • Anti-freeze design; and • Dust-proof sealing performance suitable for sandy and dusty weather conditions typical of semi-arid regions (e.g., Xianyang and Weinan). According to publicly released tender information, key technical specifications included: • Chassis: 3308 mm wheelbase; China VI emission standard; • Sewage tank capacity: 4–5 m³; • Equipped with high-pressure cleaning pump and vacuum suction system; • Filtration system maintenance interval: ≤ 500 operating hours. Chengli Special Purpose Vehicle’s EHY5045TWCE6 solution is built on a Dongfeng chassis, fully compliant with China VI emissions standards. Its upper-structure components—including tank, pumps, valves, and piping—are fabricated from freeze-resistant materials, meeting winter operation requirements. II. Key Features of the Winning Solution 1. Chassis and Upper-Structure Configuration This vehicle uses a Dongfeng chassis with a 3308 mm wheelbase, powered by a Quanchai Q23-95E60 engine delivering a maximum output of 70 kW and complying with China VI emission standards. The upper-structure—comprising the tank, pumps, valves, and piping—is independently manufactured by Chengli Special Purpose Vehicle and includes: • Sewage tank: Welded Q235 carbon steel construction with internal anti-corrosion treatment; wall thickness 4 mm; capacity 4.5 m³; • Vacuum pump system: Water-ring type vacuum pump with air extraction rate ≥ 45 m³/h and maximum vacuum level ≥ 90%; • High-pressure cleaning pump: Plunger-type pump with rated pressure 20 MPa and flow rate ≥ 80 L/min; • Piping system: Stainless steel ball valves and rubber flexible couplings, designed for freeze resistance in winter. 2. Winter-Operation Specific Design To address Xi’an’s harsh winter conditions, Chengli’s solution incorporates the following features: • Cold-start assistance: Engine intake pre-heating device installed; electronic fuel injection system automatically adjusts fuel delivery volume to ensure one-button engine start at ambient temperatures down to −15°C; • Freeze protection: Tank and piping wrapped with 20 mm-thick thermal insulation; critical valves equipped with electric heat-tracing systems; • Dust-proof sealing: Dual-layer sealing gaskets at the interface between cab and upper-structure; air filter system upgraded with desert-grade filter elements for sand-dust environments; • Filtration system maintenance: Diesel filter replacement recommended every 400 operating hours; air filter replacement every 500 operating hours—to maximize engine service life. Client Feedback: Since commissioning in January 2023, the vehicle has operated successfully under Xi’an’s extreme winter conditions, including ambient temperatures as low as −8°C, with no freezing of pipelines or jamming of pumps/valves. In March 2023, it performed emergency