I. Case Background: Sludge Suction Truck Procurement Requirement of a Municipal Sanitation Department in Nanjing In early 2025, a municipal sanitation department in Nanjing (hereinafter referred to as the 'Purchaser') urgently needed to procure a batch of sludge suction trucks under its annual sanitation equipment upgrade plan, for cleaning urban drainage pipelines, riverbed silt, and road sediment. Given Nanjing’s frequent summer flood seasons, the truck’s operational stability and efficiency were critical. After preliminary research, the Purchaser shortlisted the Dongfeng single-cab sludge suction truck (blue license plate, 5-cubic-meter capacity). The blue license plate offers clear advantages: drivable with a Class C1 driver’s license and unrestricted access within urban areas; moreover, the 5-cubic-meter tank capacity adequately meets routine sludge removal requirements. However, facing multiple competing brands on the market (e.g., Chengli, Zoomlion, Fulongma), the Purchaser adopted a 'trial-first' procurement strategy—purchasing one unit for trial use before deciding on bulk procurement. Ultimately, through a formal tender process, the Purchaser selected the Dongfeng single-cab sludge suction truck (model CLW5070GSSD6, referencing Chengli’s MIIT announcement parameters) supplied by Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as 'Chengli'). As one of China’s largest special-purpose vehicle manufacturers, Chengli maintains a product database comprising 946 models across 44 categories, and its sludge suction trucks enjoy a strong industry reputation. II. Trial Phase: A 'Litmus Test' for One Sludge Suction Truck 1. Trial Vehicle Configuration and Specifications The trial vehicle was a Dongfeng single-cab sludge suction truck (blue license plate, 5-cubic-meter capacity) manufactured by Chengli, built upon a Dongfeng chassis and compliant with China VI emission standards. Per Chengli’s product database (model CLW5070GSSD6 specifications), key configurations are as follows: Chassis Brand: Dongfeng single-cab cab, equipped with either Quanchai or Yunnan Engine, rated power approx. 85 kW, delivering ample torque suitable for low-speed urban operations. Tank Capacity: 5 cubic meters (approx. 5 m³), fabricated from high-strength steel plates with welded construction and internally coated with anti-corrosion lining, suitable for handling sewage, sludge, fecal matter, and similar media. Suction System: Equipped with a rotary vane vacuum pump, achieving a maximum suction depth of no less than 7 meters and suction rates of approximately 0.5–1 m³/minute (depending on medium viscosity). Discharge Method: Hydraulic tipping self-unloading, with maximum tank tilt angle approx. 45°, ensuring clean, residue-free discharge. Additional Features: Overflow prevention valve, liquid level indicator, hydraulic rear door locking mechanism, and standard tool kit. Reference Price: According to Chengli’s 2026 inclusive-tax landed price guide, the blue license plate 5-cubic-meter sludge suction truck (including Dongfeng chassis) has a reference landed price range of RMB 108,000–127,000 (actual pricing subject to configuration and regional policy adjustments; data source: Chengli official quotation). The Purchaser’s trial unit acquisition cost was approx. RMB 112,000 (per publicly available tender information). 2. Trial Performance Record The Purchaser deployed the trial vehicle for a 30-day sludge removal project along a river in Jiangning District, Nanjing. Key performance observations included: Operational Efficiency: Average daily sludge removal volume approx. 20 m³ (8-hour shift); suction speed remained stable, with no occurrences of clogging or vacuum pump overheating. Maneuverability: The blue license plate vehicle navigated narrow streets in Nanjing’s historic urban districts with ease and faced no traffic restrictions. The Dongfeng single-cab design provided excellent driver visibility, and operators reported intuitive, us