Against the backdrop of the nationwide implementation of China VI emission standards, municipal sanitation departments across the country are accelerating the phasing out and replacement of aging vehicles. This article analyzes a case in which a district-level sanitation department in Linyi procured Dongfeng D6 blue-plate sewage treatment vehicles, drawing on Chengli Special Purpose Vehicle Co., Ltd.’s practical delivery experience to interpret the policy context, vehicle selection criteria, and subsidy stacking strategies—providing reference guidance for similar procurement projects. I. Policy Background of the China VI Transition and Timeline for Phasing Out Older Vehicles According to the 'Notice on Implementing the National Sixth-Stage Motor Vehicle Emission Standards' jointly issued by the Ministry of Ecology and Environment and other ministries, the China VI emission standard for heavy-duty diesel vehicles has been fully implemented nationwide since July 1, 2021. For specialized sanitation vehicles, this means: • After July 1, 2023: New heavy-duty diesel vehicles failing to meet the China VIb standard will no longer be eligible for registration. • By the end of 2025: Most cities require diesel trucks meeting China III or lower emission standards to cease operations within urban core areas. • Between 2027 and 2029: Some regions have already planned designated restricted zones for China IV diesel vehicles. As a key logistics and industrial city in Shandong Province, Linyi issued its 'Implementation Plan for Phasing Out and Replacing Aging Diesel Trucks' in 2024, offering scrappage subsidies for sanitation vehicles meeting China III or lower emission standards. In Q4 2024, the Urban Management Bureau of a certain district launched a procurement initiative for sewage treatment vehicles, prioritizing blue-plate models to accommodate narrow urban roads and older residential communities. II. Linyi Case: Procurement Requirements for Dongfeng D6 Blue-Plate Sewage Treatment Vehicle The procurement project had a budget cap of approximately RMB 436,000, with plans to acquire two blue-plate sewage treatment vehicles for emergency suction, drainage, and pre-treatment operations targeting urban rivers, stormwater/sewer networks, and residential septic tanks. Key requirements included: • Chassis brand: Dongfeng or equivalent top-tier domestic brand, ensuring convenient local service station maintenance. • Emission standard: China VIb compliance to guarantee long-term regulatory conformity. • Tank capacity: Approximately 3–5 m³, compatible with Class C driver’s license operation. • Functional configuration: Self-priming suction capability, solid-liquid separation and filtration, and high-pressure flushing functionality. After comparative evaluation of proposals from multiple suppliers, Chengli Special Purpose Vehicle Co., Ltd.’s solution—based on the Dongfeng D6 light-duty chassis and model CLW5070GSSD6 sewage treatment vehicle—was selected as the winning bid. This vehicle is built upon the Dongfeng D6 light truck chassis, with a curb weight of approximately 4.5 tons and a rated payload of about 2 tons. It features a high-power vacuum pump and an integrated self-separation filtration system capable of handling wastewater with solid content below 5%. III. Chengli’s China VI-Compliant Solution and Delivery Details Chengli Special Purpose Vehicle Co., Ltd. delivered the following distinctive features in this project: • Chassis Compliance: The Dongfeng D6 chassis is certified under the China VIb standard (model CLW5070GSSD6, per MIIT announcement parameters), enabling nationwide registration and annual inspection. • Superstructure Configuration: The tank is fabricated from 4 mm-thick carbon steel with internal anti-corrosion treatment; equipped with a 7.5 kW vacuum pump delivering a maximum suction lift of 8 meters; high-pressure flushing system capable of up to 20 MPa pressure. • Delivery Lead Time: Standard models can be delivered wit