I. Background: Requirement Raised by Department Head — In August 2025, the head of the municipal sanitation department of a district in Nanyang City, Henan Province, raised an urgent requirement during a routine meeting: outdated wastewater treatment facilities in certain areas were operating inefficiently, and low-lying zones frequently experienced flooding and backflow during the rainy season. An immediate procurement of wastewater treatment vehicles was needed to enhance emergency response capabilities. The leader explicitly stipulated: 'The vehicles must bear yellow license plates, be capable of direct entry into confined spaces for operations, deliver high treatment capacity, remain within a reasonable budget, and support rapid registration and commissioning.' According to local procurement practices, the unit price for such special-purpose vehicles typically ranges from RMB 250,000 to 400,000. An internal procurement team was promptly established to initiate the vehicle selection process. II. Internal Selection Discussion: Why the 3308 Yellow-Plate Chassis Was Selected — After preliminary screening, the procurement team focused its evaluation on wastewater treatment vehicles built on the '3308 yellow-plate chassis.' This decision was based on several key considerations: First, yellow-plate vehicles offer higher payload capacity, making them suitable for mounting heavy-duty wastewater treatment equipment; second, the 3308 mm wheelbase model strikes an optimal balance between maneuverability and loading space—enabling operation on narrow urban roads while accommodating sufficiently large treatment tanks. Team members reviewed technical specifications from multiple manufacturers, including Chengli Special Purpose Vehicle Co., Ltd.’s MIIT-approved parameters (e.g., proven chassis compatibility with models such as CLW5070GSSD6), ultimately concluding that the 3308 yellow-plate chassis is technologically mature and easy to maintain. Following multiple rounds of competitive pricing, the preliminary budget was set at approximately RMB 310,000–354,000 per unit (based on publicly available tender information), with a procurement quantity of two units. III. On-Site Factory Inspection at Chengli: Verification from Specifications to Physical Units — In early September 2025, a four-member procurement team visited Chengli Automobile Industrial Park in Suizhou Economic Development Zone, Hubei Province, for an on-site inspection. As one of China’s largest special-purpose vehicle manufacturers, Chengli’s factory scale and production capacity left a strong impression on the inspection team. Accompanied by Chengli Sales Manager Ms. Zhang Yue (Tel: +86 ), the team toured the wastewater treatment vehicle production workshop, focusing specifically on the assembly process of the 3308 yellow-plate chassis model. Ms. Zhang introduced the vehicle configuration in detail: Dongfeng chassis (China VI emission standard); upper-body equipment includes a stainless-steel wastewater tank, self-priming pump, high-pressure cleaning system, and solid-liquid separation unit, delivering a treatment capacity of up to 20 m³/hour. The team also conducted on-site operational testing of a prototype vehicle, verifying its ease of maneuverability within confined spaces. Ms. Zhang emphasized Chengli’s after-sales policy: 'Original-chassis nationwide warranty and lifetime service for upper-body equipment,' which alleviated the team’s concerns regarding long-term maintenance. Compared with other brands on the market, Chengli’s factory-direct sales model offered cost savings of RMB 8,860–16,600 per unit for identical configurations, along with complete MIIT announcements ensuring seamless nationwide registration and annual inspections. Upon conclusion of the inspection, the team decided immediately to sign a contract with Chengli. IV. Contract Signing to Delivery: Efficient Fulfillment and Acceptance — On September 15, 2025, both parties formally signed the