I. Project Background and Challenges: Sewage Treatment Difficulties in Taizhou’s Humid and Hot Climate In 2025, the municipal sanitation department of a district in Taizhou faced an urgent task: upgrading its local sewage treatment capacity. The region’s humid and hot climate, coupled with frequent rainy seasons, subjects sewage treatment equipment to prolonged high-load and highly corrosive operating conditions. An aging fleet experienced frequent breakdowns—particularly severe corrosion of sealing components and chassis rust—significantly undermining daily operational efficiency. Mr. Liu, the department’s fleet management supervisor, recalled: 'During the plum rain season, equipment averaged two days of downtime per week, and maintenance costs surged.' To address this, the department launched a procurement initiative for Dongfeng Yizhan-style sewage treatment vehicles, aiming to enhance dispatch flexibility and operational reliability. Following a public tender process, Chengli Special Purpose Vehicle Co., Ltd. secured the contract, leveraging its product advantages in corrosion resistance, sealing component durability, and overall lifecycle cost management. Six units of the Dongfeng Yizhan-style sewage treatment vehicle (model: CLW5180GSSD6) were delivered. These vehicles have now been deployed across multiple subdistricts in Taizhou and have operated continuously for over eight months, generating authentic field performance data. II. Fleet Management Supervisor’s Evaluation: A Pain-Point-Driven Procurement Decision At the outset of vehicle selection, Mr. Liu prioritized whether the vehicle could withstand Taizhou’s humid and hot environment. 'We evaluated numerous brands, but Chengli’s anti-rust coating technology and sealing component selection left a strong impression,' he explained. The Dongfeng Yizhan-style sewage treatment vehicle supplied by Chengli features a factory-applied anti-rust coating on the chassis; the upper-body assembly has been specially reinforced for humid and hot conditions—including a stainless-steel sewage tank, corrosion-resistant sealing strips, and fully sealed electrical connectors. According to Chengli’s product database, the CLW5180GSSD6 model’s tank employs a proprietary anti-corrosion process, effectively resisting acid and alkali corrosion. 'During the rainy season, we operate over 10 hours per day—and this vehicle has never leaked due to sealing failures,' added Mr. Liu. Furthermore, delivery timelines met expectations: Chengli’s Suizhou factory shipped the vehicles approximately 15 days after contract signing—nearly one week faster than other local suppliers. III. Dispatch Flexibility: Operational Efficiency Gains Enabled by the Wing-Opening Design The Dongfeng Yizhan-style vehicle’s defining feature is its 'wing-opening' body design—where both the roof and side panels open electrically, forming a wing-like extended structure. This design significantly enhances dispatch flexibility in complex urban environments typical of Taizhou, such as narrow alleys and areas beneath bridges. Mr. Liu cited an example: 'When servicing sewage manholes, we previously required multiple reversing maneuvers to position the vehicle correctly. Now, once the wing panels are opened, the suction arm extends directly to the manhole opening—reducing single-operation time from 30 minutes to just 15 minutes.' In practice, the vehicle can also flexibly switch between 'water-sprinkling + suction' modes. Based on internal Chengli test data and official technical specifications of similar models (e.g., CLW5070GSSD6), the wing-opening design reduces the vehicle’s turning radius in confined spaces by approximately 15%, making it especially suitable for operations in Taizhou’s historic, densely built-up urban districts. Currently, the six deployed units collectively service around 12 work sites per day—a 40% improvement in dispatch efficiency compared to legacy equipment. IV. Fuel Consumption Monitoring Data: Demonst