Beijing Dongfeng D6 Sewage Treatment Vehicle (Blue License Plate) Government Procurement Case: Emergency Procurement and Winter Operation Strategy Interpretation — In winter 2025, a municipal sanitation department in a district of Beijing faced an urgent challenge: aging sewage treatment facilities malfunctioned due to prolonged low temperatures, causing overflows in street septic tanks and sewer networks, necessitating immediate procurement of compact, maneuverable sewage treatment vehicles. Given operational constraints—including narrow alleys and underground garage entrances—conventional large-scale vacuum trucks were impractical; thus, blue license plate vehicles became the clear procurement priority. Following emergency tendering and evaluation, sewage treatment vehicles based on the Dongfeng D6 chassis, supplied by Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as 'Chengli'), were selected as the solution. Based on publicly available tender information and official technical specifications (e.g., Chengli model CLW5070GSSD6), this article analyzes this emergency procurement case, with particular focus on freeze-resistant engine starting, hydraulic system stability at low temperatures, and winter-specific maintenance strategies—key concerns for northern users. I. Background of the Urgent Requirement: Why Choose a Blue License Plate Vehicle for Winter Emergency Response? The timeline traces back to mid-December 2025, when Beijing experienced consecutive days of sub-zero temperatures down to –15°C. A district-level municipal sanitation department received multiple complaints regarding sewage overflows. Existing vacuum trucks were unavailable due to lengthy repair cycles and inflexible dispatch arrangements, rendering them incapable of timely response. As recalled by the procurement manager: 'At that time, we needed vehicles that could be delivered and put into operation within three days—and they had to comply with blue license plate regulations, since many work sites have height restrictions of 2.2 meters and require only a Class C1 driver’s license.' The advantages of blue license plate sewage treatment vehicles (e.g., Chengli model CLW5070GSSD6) became immediately evident: Maneuverability: Overall vehicle length