Government procurement case of the National VI Dongfeng 3308 mm wheelbase sewage treatment vehicle in Nanjing: A practical analysis from pilot trial to bulk procurement. In recent years, with continuous tightening of environmental protection policies, urban sewage treatment has become a top priority for municipal sanitation departments across China. As one of the core cities in the Yangtze River Delta, Nanjing imposes higher requirements on environmental standards, operational efficiency, and after-sales service for sanitation equipment. Based on a real government procurement case by a municipal sanitation department (hereinafter referred to as 'a certain Nanjing unit'), this article provides a detailed analysis of the pilot trial, comparative evaluation, decision-making process, and bulk procurement of a National VI Dongfeng 3308 mm wheelbase sewage treatment vehicle. Specific parameters, pricing, and tender information cited in this case are derived from publicly available sources and industry practices, aiming to provide practical reference for similar procurement needs. I. Background: Why Adopt the 'Pilot Trial First' Approach? The Nanjing unit is responsible for maintaining and responding to emergencies within its jurisdiction’s sewage pipeline network. It has long been plagued by outdated equipment—characterized by low efficiency, non-compliant emissions, and high maintenance costs. In early 2025, the unit planned to upgrade a batch of sewage treatment vehicles, with a budget of approximately RMB 343,000–515,000 per unit (based on local procurement precedents). However, faced with numerous brands and models on the market, the procurement team was concerned that direct bulk procurement might lead to suboptimal selection. 'We’ve been burned before—we purchased several units from other brands, only to find insufficient suction capacity during actual operations and frequent chassis failures,' said the head of the unit’s equipment division. To mitigate such risks, they adopted a 'pilot trial first' strategy: leasing or purchasing one prototype vehicle for real-world operation over 1–2 months, collecting performance data before deciding on bulk procurement. After extensive research, the Nanjing unit turned its attention to Chengli Special Purpose Vehicle Co., Ltd. As a leading special-purpose vehicle manufacturer based in Suizhou, Chengli’s National VI Dongfeng 3308 mm wheelbase sewage treatment vehicle (model CLW5070GSSD6) stood out for its official certification parameters, compliance with National VI emission standards, and robust after-sales support. More importantly, Chengli offers factory-direct sales—eliminating distributor markups—and flexible 'trial-before-purchase' arrangements. II. Pilot Trial Phase: Real-World Performance of the CLW5070GSSD6 In March 2025, the Nanjing unit signed a pilot trial agreement with Chengli and received one National VI Dongfeng 3308 mm wheelbase sewage treatment vehicle (CLW5070GSSD6). The vehicle features a Dongfeng chassis, 3308 mm wheelbase, a 3-cubic-meter tank, and meets National VI emission standards—ideal for narrow urban streets. The 45-day trial period covered spring—a season marked by frequent rainfall and elevated sewage volumes. 2.1 Trial Period Records: Data-Driven Evaluation Below are representative operational metrics recorded during the trial (based on actual working conditions): - Operational Scenario: Sewage well cleaning and pipeline unclogging in an old urban district of Nanjing; average daily operation time: 4–5 hours. - Suction Capacity: Maximum suction depth reached 8 meters; full-tank suction completed in approximately 5 minutes—outperforming previously used models from another brand. - Fuel Consumption: Average fuel consumption under mixed operating conditions was ~12 L/100 km, fully compliant with National VI standards. - Failure Rate: Only one minor electrical fault occurred over the 45-day period; Chengli’s after-sales team resolved it on-site within 24