I. Case Background: Analysis of Sludge Suction Truck Procurement Requirements by a Municipal Sanitation Department in Lanzhou In 2025, a municipal sanitation department in Lanzhou required procurement of a batch of sludge suction trucks for cleaning drainage networks, stormwater inlets, and riverbed sediments within the urban area. Located in the inland northwest of China, Lanzhou exhibits typical desertification climate characteristics: windy and sandy springs, dry and low-rainfall summers, cold winters, and frequent heavy dust at operation sites. Consequently, the procuring entity specified three core requirements: dust-proof sealing performance, adaptability to desertified-region operations, and ease of maintenance for the filtration and cleaning system. After multiple rounds of tendering and solution comparisons, the department ultimately selected the Dongfeng single-cab blue license plate 5-cubic-meter sludge suction truck (model reference: CLW5070GSSD6) manufactured by Chengli Special Purpose Vehicle Co., Ltd., ordering approximately five units at a unit price of around RMB 110,000 (based on publicly available tender information). This solution not only fulfills basic sludge suction functionality but also incorporates targeted optimizations addressing local environmental challenges in Lanzhou. II. Tank Capacity Selection & Structural Configuration: How to Choose Among 3 m³ / 5 m³ / 8 m³ / 12 m³? Selection of sludge suction truck tank capacity must comprehensively consider daily workload, operational radius, road access restrictions, and budget constraints. Based on Chengli’s product database and real-world tender data, the following selection guidelines are provided: | Capacity (m³) | Chassis Type | Typical Application Scenarios | Daily Workload (m³/day) | Reference On-Road Price (RMB 10,000s) | Driver’s License Requirement | |---------------|--------------|-------------------------------|--------------------------|----------------------------------------|----------------------------| | 3 m³ | Dongfeng Light Truck / Foton | Narrow alleys, residential communities, small stormwater inlets | 10–20 | 9.5–12 (per Chengli FAQ) | C1 (Blue License Plate) | | 5 m³ (Recommended) | Dongfeng Single-Cab / Sinotruk | Urban main roads, pipeline network cleaning | 20–40 | 9.8–11.5 (per Chengli 2026 tax-inclusive pricing) | C1 (Blue License Plate) | | 8 m³ | Dongfeng Dorica / FAW Jiefang | Industrial parks, large rivers | 40–60 | 14.5–17.8 (per Chengli 2026 tax-inclusive pricing) | B2 (Yellow License Plate) | | 12 m³ | Dongfeng Tianlong / Shaanxi Automobile | Long-distance transport, large pumping stations | 60–80 | 19.8–24.5 (per Chengli 2026 tax-inclusive pricing) | B2 (Yellow License Plate) | Selection Recommendation: For cities like Lanzhou—where operations are predominantly urban-based and road access is constrained (e.g., bridge height limits, narrow lanes in historic districts)—the blue license plate 5 m³ model represents the optimal balance between daily workload capacity and traffic accessibility. In this procurement case, the customer selected the 5 m³ configuration precisely because it supports a daily workload of approximately 25–35 m³, covers ~80% of urban operation points, and offers operational flexibility without requiring a B2 driver’s license (C1 suffices). III. Daily Workload Calculation Formula & Workload Matching To assist procurement entities in scientifically evaluating vehicle configurations, the following calculation formula—derived from actual field operation data—is provided: Daily Workload (m³/day) = (Single-Operation Capacity × Daily Operation Frequency) × Load-Factor (0.85–0.95) • Single-Operation Capacity = Tank Volume × Sludge Density Factor (typically 0.8–1.2 tons/m³, depending on sludge moisture content) • Daily Operation Frequency = Determined by transport distance and operational efficiency. Assuming one round-trip takes 1 hour and total working time per day is 8 hours, theoretical frequency is 8