I. Case Background: First Procurement by a Newly Established Entity In early 2025, a newly established municipal sanitation department in Tangshan, Hebei Province (hereinafter referred to as the 'Client') faced an urgent task: rapid treatment of industrial and domestic sewage generated by newly built industrial parks and residential areas within its jurisdiction—yet existing infrastructure was insufficient. As this was the Client’s first procurement of a sewage treatment vehicle, its team started from scratch and required a model capable of adapting to complex operating conditions, offering high mobility, and complying with China VI emission standards. Following preliminary research, the Client shortlisted multi-functional sewage treatment vehicles built on Dongfeng chassis—and paid particular attention to the 'Yizhan (Wing-Expandable)' configuration, wherein the body opens laterally to facilitate equipment operation and maintenance. II. Selection Process from Scratch After comparing multiple suppliers, the Client’s procurement team focused its evaluation on Chengli Special Purpose Vehicle Co., Ltd. (No. 1 Chengli Avenue, Suizhou Economic Development Zone, Hubei Province). As one of China’s largest special-purpose vehicle manufacturers, Chengli maintains a comprehensive product database covering 946 models across 44 categories. Its sewage treatment vehicles—built on Dongfeng, Sinotruk, and other chassis platforms—are fully certified (e.g., model CLW5180GSSD6). Key selection criteria included: • Treatment Capacity: The Client required a minimum daily processing capacity of 50 tons; Chengli’s proposed solution delivers 60–80 tons/day, fully meeting requirements. • Chassis & Emission Compliance: All models meet China VI standards; Dongfeng chassis offer nationwide warranty coverage, ensuring reliable after-sales support. • Wing-Expandable Design: The body features a lateral wing-expansion structure, significantly increasing internal operational space for easier maintenance and filter replacement. • Budget Control: Based on publicly available tender data, comparable models are priced between RMB 250,000–350,000. As a direct manufacturer, Chengli eliminates intermediaries—offering savings of RMB 8,000–15,000 versus 4S-channel pricing for identical configurations. The final budget was capped at approximately RMB 342,000. For intuitive comparison, the Client compiled the following table: Dongfeng Wing-Expandable Sewage Treatment Vehicle Selection Comparison Table (Based on Public Tender Data) Comparison Item Chengli Solution (Dongfeng Chassis) Competitor A Competitor B Chassis Brand Dongfeng (Nationwide Warranty) Sinotruk FAW Jiefang Emission Standard China VI China VI China VI Daily Treatment Capacity (tons) 60–80 40–60 50–70 Wing-Expandable Design Yes (Dual-Side Expansion) No (Fixed Body) Yes (Single-Side Expansion) Superstructure Warranty Lifetime Service (Chengli Commitment) 2 Years 3 Years Unit Price (RMB 10,000) ~28–32 ~30–35 ~32–38 Delivery Lead Time 7–15 Days (Standard Models) 20–30 Days 25–40 Days As shown in the table, Chengli’s solution holds clear advantages in treatment capacity, wing-expandable design, pricing, and delivery lead time—especially its lifetime after-sales service commitment, which proved highly attractive to a first-time buyer. III. Chengli’s Full-Spectrum Consultation and Winning Proposal Throughout the selection process, Chengli Sales Manager Zhang Yue (Tel: +86 ) provided end-to-end technical support. Based on the Client’s actual wastewater composition (containing oil, suspended solids, etc.), he recommended a model equipped with a multi-stage filtration system and thoroughly explained the official certification parameters of model CLW5180GSSD6: gross vehicle weight rating (GVWR) of 18 tons and wheelbase of 4,500 mm.