I. Case Background: Aging Equipment Fails to Meet Demand; Sludge Transportation Efficiency Becomes a Critical Pain Point. In early 2025, a municipal sanitation department in a prefecture-level city (hereinafter referred to as the 'Client') routinely handled sludge collection and transportation tasks across multiple wastewater treatment plants and pumping stations within a ~30-km urban radius. Previously deployed aging tipper trucks—non-specialized vehicles with approximate capacity of 2.5 m³—had been in service for over eight years, suffering frequent breakdowns. Moreover, non-standard modifications resulted in inadequate sludge sealing, causing leakage en route and repeated complaints from residents. Additionally, one onboard cleaner was required daily per vehicle to clean the rear body and road surface, significantly increasing labor costs. The Client urgently needed a batch of specialized sludge tipper trucks compliant with China VI emission standards, with moderate capacity (~3 m³), eligible for blue license plates (drivable with C1 driver’s license), featuring excellent sealing performance, high self-unloading efficiency, and direct compatibility with wastewater plant discharge chutes. After multiple rounds of comparative evaluation and on-site inspections, the Client selected Chengli Special Purpose Vehicle Co., Ltd.’s Dongfeng D6 Blue-Plate Sludge Tipper Truck (reference announcement model: CLW5040ZWXD6 series; actual model subject to contract). The initial order comprised two units, with total budget controlled at ≤ RMB 262,000 (based on publicly available tender data, unit price approx. RMB 115,000). II. Performance Comparison Before and After Deployment: Daily Operational Volume Increased by Over 40% According to Client feedback, since commissioning in April 2025, sludge transportation efficiency has improved significantly. Key performance metrics before and after deployment are summarized below: | Comparison Dimension | Legacy Vehicles (2.5 m³, Non-Specialized) | Chengli Dongfeng D6 Blue-Plate Sludge Tipper Truck | Improvement | |------------------------|---------------------------------------------|-----------------------------------------------------|-------------| | Single-Trip Loading Capacity | ~2.5 m³ | 3 m³ (announced capacity) | +20% | | Daily Trips | 5–6 trips (limited by unloading efficiency) | 8–9 trips | +40% to +50% | | Daily Transport Volume | ~12.5–15 m³ | ~24–27 m³ | +60% to +80% | | Crew Configuration | 2 personnel per vehicle (driver + onboard cleaner) | 1 driver only (excellent sealing eliminates need for cleaning) | 50% reduction in personnel | | Single-Trip Unloading Time | 8–12 minutes (manual assistance required for pushing/sliding) | 3–5 minutes (hydraulic tipping, fully automated with one-button operation) | >60% reduction | | Monthly Operating Cost | ~RMB 18,000 (including fuel, maintenance, labor) | ~RMB 11,000 (improved fuel economy, no additional labor) | ~39% reduction | Data Source: Client’s monthly operational reports and post-sales follow-up records from Chengli. Actual figures may vary slightly depending on road conditions, sludge moisture content, etc., but overall trends remain consistent. III. Core Drivers of Efficiency Gains: Optimal Alignment Between Vehicle Design and Real-World Application The above efficiency improvements stem primarily from the following design advantages: • Blue License Plate Advantage: Gross vehicle weight ≤ 4.5 tons enables blue license plate registration; operable with C1 driver’s license—lowering driver qualification thresholds and eliminating the need to hire B-class licensed drivers, resulting in notable labor cost savings. • Sealed Body + Self-Unloading Functionality: Body constructed from high-strength steel plates with welded joints; rear door fitted with sealing strips to prevent leakage during transit. Hydraulic tipping system provides large lifting angle and complete sludge discharge—eliminating manual assistance and drastically reducing