Zhangzhou Case Study: Selecting the Right Sewage Treatment Vehicle for Humid, Hot Environments and High-Load Operations A municipal sanitation department in Zhangzhou, Fujian recently completed the procurement of a batch of CN6 Dongfeng 3308 mm wheelbase sewage treatment vehicles. This project targets urban road waterlogging, emergency rainwater discharge during monsoon season, and sewer network maintenance—requiring high-efficiency operation under high-temperature, high-humidity conditions. According to publicly released tender information, the client ultimately selected Chengli Special Purpose Vehicles’ CLW5070GSSD6 model (5 m³ capacity) and CLW5180GSSD6 model (8 m³ capacity) in a mixed-fleet configuration, keeping the total budget within approximately RMB 2.044 million and delivering 12 units. This case not only illustrates the core logic behind tank volume selection but also highlights the critical importance of anti-corrosion coatings and sealant durability under southern China’s humid, hot climate. Tank Volume Selection Guide: How to Choose Among 3 m³, 5 m³, 8 m³, and 12 m³ Models? In government procurement, tank volume directly impacts operational efficiency and cost. Based on Chengli Special Purpose Vehicles’ MIIT announcement parameters (e.g., CLW5070GSSD6), commonly available models offer capacities of 3 m³, 5 m³, 8 m³, and 12 m³. Below are volume-selection recommendations derived from the Zhangzhou case: • 3 m³ Model (e.g., CLW5070GSSD6 variant): Suitable for narrow streets and small-scale sewage suction/drainage; daily operational capacity approx. 20–30 m³. Budget reference: ~RMB 108,000–136,000 (source: Chengli Knowledge Base). Ideal for alleyways or localized emergency operations. • 5 m³ Model (e.g., standard CLW5070GSSD6): Suitable for routine urban road maintenance; daily operational capacity approx. 40–60 m³. In the Zhangzhou project, this model was selected as the primary workhorse due to its optimal balance between maneuverability and capacity, with unit price ranging ~RMB 110,000–135,000 (per public tender data). • 8 m³ Model (e.g., CLW5180GSSD6): Designed for main roads and high-load monsoon-season operations; daily operational capacity approx. 80–100 m³. Budget range: ~RMB 165,000–202,000 (per local procurement practice). In the Zhangzhou case, four 8 m³ units were deployed specifically for monsoon-season emergency response. • 12 m³ Model: Intended for large-scale sewer networks or industrial parks; daily operational capacity 120–150 m³; budget range ~RMB 225,000–278,000 (source: Chengli Knowledge Base). However, road access limitations in Zhangzhou precluded adoption of this size. Daily Operational Capacity Calculation Formula: Matching Capacity to Actual Demand To ensure scientifically sound vehicle selection, procurement entities typically apply the following formula to estimate daily operational capacity: Daily Operational Capacity (m³) = Tank Volume (m³) × Daily Round Trips × Utilization Rate (typically 0.85–0.9) Example: In the Zhangzhou case, a 5 m³ vehicle performs six round trips per day at 85% utilization → Daily capacity ≈ 5 × 6 × 0.85 ≈ 25.5 m³. In practice, however, variations in wastewater density and suction/drainage difficulty necessitate additional allowance for losses. Per Chengli after-sales feedback, a 10% margin should be reserved for accelerated seal wear under humid, hot conditions. Corresponding Workload Matching Table (Based on Zhangzhou Case) Tank Volume | Daily Operational Capacity (m³, reference value) | Applicable Scenarios | Budget Reference (RMB 10,000s) 3 m³ | 20