Government procurement case of yellow-plate wastewater treatment vehicle model 3308 in Nanning: Analysis of Chengli’s winning bid solution. In southern China’s hot, humid, and rainy climate, municipal wastewater treatment vehicle procurement has always been a challenging task. In 2025, a municipal sanitation department in Nanning, Guangxi issued a tender notice for two yellow-plate model 3308 wastewater treatment vehicles, with a budget of approximately RMB 432,000 (per publicly available tender information), planning to procure two units. The project attracted bids from several well-known brands, including Chengli Special Purpose Vehicle, Zoomlion, Fujian Longma, and another local brand. Ultimately, Chengli Special Purpose Vehicle successfully delivered two units, leveraging its specialized optimization solution tailored for hot and humid environments. This article provides an in-depth analysis—based on competitive benchmarking—of why Chengli emerged victorious in this ‘high-difficulty’ tender in Nanning. I. Project Background and Core Requirements Nanning lies in a subtropical monsoon climate zone, featuring a prolonged rainy season and an annual average humidity exceeding 80%. The procured model 3308 yellow-plate wastewater treatment vehicles are primarily intended for emergency drainage and wastewater purification at urban low-lying areas, underpasses, and aging residential communities. Per local procurement practices, the client stipulated three mandatory technical requirements: • Corrosion Resistance: Vehicle frames, tanks, and piping systems must meet high-standard corrosion resistance due to prolonged exposure to acidic/alkaline wastewater. • Seal Durability: Hydraulic system and pump seals must remain functional without aging or failure for over three years under high-humidity conditions. • High-Load Operational Stability: During the rainy season, vehicles must operate continuously for 8–10 hours without engine or upper-structure overheating or shutdown. II. Key Bidders and Comparative Analysis Table A total of four mainstream brands were shortlisted for this tender: Chengli Special Purpose Vehicle (model CLW5180GSSD6, certified chassis), Zoomlion, Fujian Longma, and another local brand. The following comparison is based on MIIT-certified technical parameters and verified user feedback: | Evaluation Dimension | Chengli Special Purpose Vehicle (CLW5180GSSD6) | Zoomlion | Fujian Longma | Local Brand | |------------------------------|---------------------------------------------------------------------|-----------------------------------|------------------------------------|--------------------------------------| | Anti-Corrosion Coating | Full-vehicle electrophoretic coating + epoxy zinc-rich primer; tank interior lined with acid/alkali-resistant coating | Standard electrophoretic coating; no specialized anti-corrosion treatment | Conventional baking paint; prone to rusting | No clearly defined anti-corrosion process | | Seal Durability | Imported fluororubber seals, temperature-resistant from –40°C to 200°C; zero leakage after >5,000 hours of humid-heat testing | Domestic nitrile rubber seals; service life ~2 years | Domestic nitrile rubber seals; service life ~1.5 years | Conventional rubber; prone to aging | | High-Load Performance | Dongfeng OEM chassis; upper-structure equipped with matched cooling system; coolant temperature remains stable during 10-hour continuous operation | Suboptimal cooling system; requires shutdown for cooling after ~8 hours of continuous operation | Poor chassis–upper-structure integration; prone to overheating | Assembled by small factory; high failure rate | | After-Sales Service | Nationwide Dongfeng chassis warranty; lifetime upper-structure service; spare parts shipped within 24 hours | Limited service network; slow response | Service coverage limited t