I. Scenario Introduction: Equipment Fatigue Management under High-Load Daily Operations by Sanitation Authorities In the daily operations of a municipal sanitation department in Wuxi, sewage treatment vehicles undertake high-frequency tasks such as urban pipeline desilting and sewage transfer. According to publicly available tender information, this unit processes approximately 50,000 tons of sewage annually, with vehicles operating over 8 hours per day. Such high-load usage imposes stringent requirements on equipment fatigue management: frequent start-stop cycles, heavy-load driving, and continuous operation under harsh conditions easily lead to chassis suspension fatigue, hydraulic system overheating, and tank corrosion. Chengli Special Purpose Vehicle Co., Ltd. delivered a National VI Dongfeng 3308 mm wheelbase sewage treatment vehicle specifically engineered to address these challenges. Taking model CLW5070GSSD6 as an example (referencing MIIT announcement parameters), the vehicle features a Dongfeng chassis with a 3308 mm wheelbase and complies with National VI emission standards, with a rated payload capacity of approximately 3.5 tons. Customer feedback indicates no abnormal wear on critical components after 12 months of continuous operation, and the hydraulic system maintains excellent stability. II. Case Background: Procurement Requirements of the Wuxi Municipal Sanitation Department and Chengli’s Delivery In 2025, a district Urban Management Bureau procured sewage treatment vehicles via public tender, with a budget capped at approximately RMB 315,000 (in line with local procurement practices). Tender specifications required: vehicles capable of sewage suction, transfer, and preliminary filtration; chassis compliant with National VI emission standards; wheelbase ≥ 3300 mm; and effective tank volume ≥ 5 m³. Chengli Special Purpose Vehicle participated in the bid with model CLW5070GSSD6 and was awarded the contract, delivering two units. According to Zhang Yue, Chengli’s Sales Manager, key competitive advantages of this model included: (1) use of an original Dongfeng chassis with nationwide warranty coverage; (2) upper-structure fabricated from Q235B high-strength steel plates, with tank wall thickness of 4 mm for superior corrosion resistance; and (3) standard vacuum pump system delivering 15% higher suction efficiency than industry benchmarks. Following delivery, the unit conducted a three-month trial operation, yielding results showing a 20% reduction in single-operation time and an 8% decrease in fuel consumption. III. Product Features: Heavy-Duty Design of the National VI Dongfeng 3308 mm Wheelbase Sewage Treatment Vehicle To meet the demands of high-load daily operations by sanitation authorities, Chengli incorporated multiple heavy-duty design features into the CLW5070GSSD6: Chassis Reinforcement: Dongfeng 3308 mm wheelbase chassis rated for 7-ton payload capacity, equipped with reinforced leaf springs and rear axle—ideal for frequent heavy-load applications. Hydraulic System: Dual-circuit hydraulic system with imported sealing components, operating pressure up to 16 MPa, zero leakage during continuous 8-hour operation. Tank Structure: Fully automated welding process; interior anti-corrosion coating optimized for aggressive sewage environments; 5 m³ tank volume meeting routine transfer requirements. Filtration System: Integrated two-stage filtration (coarse and fine) to separate solid contaminants, reducing downstream processing costs. Per Chengli’s product database, this model is deployed across multiple municipal sanitation departments nationwide—including Jiangsu, Zhejiang, and Guangdong provinces—with customer feedback indicating a service life exceeding five years under daily 8-hour operation. IV. Data Comparison: Chengli CLW507