I. From Referral by an Existing Customer to Actual Delivery: The Procurement Journey of the Deyang 3308 Yellow-Plate Sewage Treatment Vehicle In 2025, a municipal sanitation department in Deyang City, Sichuan Province (hereinafter referred to as the "Purchaser") planned to procure a 3308 yellow-plate sewage treatment vehicle to enhance local sewage treatment capacity. This requirement originated from a routine environmental remediation meeting, where it was noted that aging sewer networks suffered severe blockages, rendering conventional vacuum trucks ineffective for direct treatment—thus necessitating a high-efficiency unit capable of simultaneous suction and on-the-spot treatment. Having no prior experience with such vehicles, the Purchaser initially struggled with model selection. The turning point came during an industry exchange. The Purchaser’s project manager learned incidentally that a neighboring district’s urban management bureau had procured a similar vehicle in 2024, with highly positive operational feedback. Following a phone consultation, the bureau confirmed: “We use Chengli Special Purpose Vehicles’ sewage treatment vehicle—built on the Dongfeng 3308 chassis—with strong upper-body processing capability and responsive after-sales support.” This recommendation directly sparked the Purchaser’s interest in Chengli. The Purchaser promptly contacted Zhang Yue, Sales Manager at Chengli Special Purpose Vehicles (Tel: +86 ), requesting a detailed proposal. After clarifying the requirements, Zhang Yue swiftly developed a sewage treatment solution based on the official model CLW5070GSSD6 (an upgraded 5-cubic-meter vacuum truck variant) and recommended the 3308 yellow-plate chassis—selected for its balanced payload capacity and excellent maneuverability, ideal for Deyang’s hilly terrain. Following two rounds of technical discussions and an on-site inspection, the Purchaser finalized the order for one unit, with a budget capped at approximately RMB 320,000 (per publicly available tender data). From initial inquiry to formal contract signing, the entire process took less than 20 days. Chengli completed chassis modification and upper-body commissioning at its Suizhou facility and shipped the vehicle just seven days later. The Purchaser remarked: “It arrived much faster than expected—and lifetime upper-body service gives us real peace of mind.” II. The Trust Chain Behind Peer Recommendations: How Chengli Built Its Reputation Chengli Special Purpose Vehicles secured the Deyang order primarily through reputation earned over years of consistent service. According to Chengli’s internal knowledge base, the company has served over 500 municipal sanitation agencies—including Wuhan Urban Management Bureau (15 street-sweeping vehicles), Guangdong Industrial Park (5 water-sprinkling trucks + mist cannons), and Henan Sanitation Office (10 x 5-cubic-meter water-sprinkling trucks). These projects not only validated product quality but also fostered organic word-of-mouth referrals from existing to new customers. In the Deyang procurement case, key decision drivers included: • Chassis Nationwide Warranty Advantage: Dongfeng chassis are covered under a nationwide warranty network, eliminating concerns about out-of-area repairs. • Lifetime Upper-Body Service: Chengli guarantees lifetime after-sales support for the upper-body assembly, with spare parts dispatched within 24 hours—a critical advantage for non-standard equipment like sewage treatment vehicles. • Comprehensive Regulatory Compliance: The 3308 yellow-plate sewage treatment vehicle is fully compliant with national type-approval regulations, enabling seamless registration, annual inspection, and commercial operation across all provinces—avoiding regional policy restrictions. • Transparent Pricing: Chengli adheres to factory-direct sales, eliminating distributor markups. Comparative analysis by the Purchaser indicated savings of RMB 8,000–15,000 versus equivalent configur