Government Procurement Case and Bid-Winning Solution Analysis of the Dongfeng D6 Blue License Plate Sewage Treatment Vehicle in Lanzhou In Northwest China—especially in Lanzhou and surrounding desertified, high-dust environments—municipal sanitation departments prioritize vehicle reliability and adaptability under harsh operating conditions over price when procuring special-purpose vehicles. This article takes the procurement of a Dongfeng D6 blue license plate sewage treatment vehicle by a municipal sanitation department in Lanzhou as a case study, providing an in-depth interpretation of how a site-specific matching solution addresses core challenges such as dust-proof sealing and filter system maintenance. The analysis is based on publicly available tender information from Chengli Special Purpose Vehicle Co., Ltd. If you have similar procurement needs, please contact Chengli’s official hotline at or Sales Manager Zhang Yue at for a customized quotation. I. Project Background and Operational Challenge Analysis In 2025, a district-level municipal sanitation department in Lanzhou launched a procurement project for sewage treatment vehicles, with a budget capped at approximately RMB 336,000. Requirements included: blue license plate compliance (drivable with Class C driver’s license), access to urban restricted-traffic zones, and capability for sewage suction and preliminary purification. During the initial phase, multiple suppliers competed; however, the procuring entity ultimately focused on “operational suitability.” Lanzhou lies at the transitional zone between the Loess Plateau and the Qinghai-Tibet Plateau, experiencing over 30 sandstorm days annually. Winters are cold and dry, with severe road surface dust accumulation. Conventional sewage treatment vehicles often ingest sand and dust into water tanks and pipelines during operation, leading to clogged filters, accelerated pump wear, and increased hydraulic system failure rates. Although the Dongfeng D6 chassis offers strong versatility, its original equipment air and oil filters require maintenance every 2,000 km—rather than the standard 5,000 km—in desertified regions; otherwise, power loss and sharply increased fuel consumption may occur. Moreover, due to size limitations imposed on blue license plate vehicles, tank capacity typically does not exceed 4 m³. Integrating efficient filtration and dust-proof structures within this constrained space presents a key technical challenge. Chengli Special Purpose Vehicle Co., Ltd. conducted targeted optimizations on the CLW5070GSSD6 model specifically for such conditions—forming the technical foundation for the final selected procurement solution. II. Site-Specific Matching Solution: Recommended Parameters for Three Typical Operating Scenarios Based on operational characteristics in Lanzhou and Northwest China, procurement requirements were categorized into three representative scenarios, each with corresponding optimal parameter recommendations: 1. Light-Duty Municipal Operations (Street Drainage Network Maintenance) Operating Scenario: Cleaning of sewage and rainwater manholes along urban main roads and alleys; average daily workload: ~20 m³. Recommended Parameters: Chassis: Dongfeng D6 blue license plate (official model number: CLW5070GSSD6) Tank Capacity: 3–4 m³ (maximum compliant capacity for blue license plate vehicles) Engine Power: 85–95 kW Maximum Suction Depth: 8 meters Dust-Proof Configuration: Dual-stage filtration (cabin air filter + chassis air filter) Filter System Maintenance Interval: Recommended inspection every 1,500–2,000 km or biweekly 2. Heavy-Duty Industrial Operations (Industrial Park & Factory Wastewater Treatment) Operating Scenario: Treatment of oily and sandy wastewater from industrial parks and logistics bases; average daily workload: ~40–60 m³. Recommended Parameters: Chassis: Dongfeng D6 or Dongfeng Duolika (yellow license plate; reference model C