Case Background: Sewage Treatment Vehicle Procurement Requirement of a Municipal Sanitation Department in Foshan City In the second half of 2025, a municipal sanitation department in Foshan City, Guangdong Province, planned to procure a batch of National VI emission-standard sewage treatment vehicles for emergency sewage treatment in urban rivers, drainage networks, and industrial parks. Located in the Pearl River Delta, this region features a typical subtropical humid climate with high annual rainfall and frequent rainy seasons—imposing stringent requirements on vehicle corrosion resistance, sealing component durability, and operational stability under heavy-load conditions. After multiple rounds of tender evaluation, Chengli Special Purpose Vehicle Co., Ltd. was selected, supplying a series of sewage treatment vehicles built on the Dongfeng 3308 mm wheelbase chassis. The core challenges of this procurement were: how to match varying operational volume requirements across different application scenarios within a controlled budget, while ensuring long-term reliability under high-temperature, high-humidity, and high-frequency usage conditions. According to publicly released tender information, the department ultimately delivered multiple sewage treatment vehicles of varying capacities—including 3 m³, 5 m³, 8 m³, and 12 m³ models—to cover diverse tasks ranging from residential sewer cleaning to large-scale river emergency response. Capacity Selection Logic: How to Choose Among 3 m³ / 5 m³ / 8 m³ / 12 m³ Models? In government procurement, sewage treatment vehicle capacity selection is not arbitrary but rather determined through comprehensive trade-offs involving daily workload, operating radius, road restrictions, and budget constraints. Below are key selection criteria derived from Chengli’s product database and real-world case experience: 3 m³ (Blue License Plate): Ideal for narrow streets, old residential communities, and alleys with limited space; operable with a Class C1 driver’s license, offering high maneuverability. Daily workload: ~20–30 m³—suitable for single-operator or two-person crews. 5 m³ (Blue or Yellow License Plate): Balances tank capacity and maneuverability; suitable for urban secondary roads, industrial parks, and township sanitation stations. Daily workload: ~40–60 m³—serving as the primary model for small- and medium-sized municipal units. 8 m³ (Yellow License Plate): Features a larger tank, ideal for main roads, primary drainage network lines, and large industrial facilities. Daily workload: ~80–100 m³; requires a Class B2 driver’s license—suited for medium- to large-scale operations. 12 m³ (Yellow License Plate): High-capacity design intended for river dredging, emergency rescue, and cross-regional operations. Daily workload: ~120–150 m³; requires a Class A2 or B2 driver’s license—ideal for high-intensity, high-frequency applications. Based on actual tender data, in the Foshan case, the department prioritized 5 m³ and 8 m³ models as its core fleet, complemented by a smaller number of 3 m³ and 12 m³ units to form a tiered configuration. Regarding pricing, local procurement practice indicates the following estimated tax-inclusive landed prices for 2026: ~¥112,000–¥132,000 for blue-plate 5 m³ sewage treatment vehicles; ~¥145,000–¥178,000 for yellow-plate 8 m³ models; ~¥198,000–¥245,000 for 12 m³ models; and ~¥95,000–¥120,000 for 3 m³ vacuum suction trucks. Daily Workload Calculation Formula and Matching Reference Table To assist municipal authorities in scientifically planning procurement quantities, here is a general-purpose daily workload calculation formula: Daily Workload (m³/day) ≈ Tank Capacity (m³) × Daily Operation Frequency × Actual Loading Factor (typically 0.85–0.95) Example: