I. Case Background: Upgraded Municipal Sludge Transportation Requirements In 2025, the municipal sanitation department of a district in Changsha faced a sharp increase in sludge volume from local wastewater treatment plants and pipeline desilting operations. Its existing fleet of small trucks (5–8 m³) could no longer meet the daily sludge transportation demand of 180–220 tons. Moreover, stricter environmental regulations necessitated procurement of large-capacity, fully sealed, China VI–compliant sludge tipper trucks. Following a public tender, five 24 m³ Sinotruk-chassis sludge tipper trucks were procured and delivered by Chengli Special Purpose Vehicle Co., Ltd. According to publicly available tender information, the project’s total budget was controlled within approximately RMB 3.191 million, with an estimated unit price of around RMB 560,000 per vehicle—including transportation, registration, first-year insurance, and chassis extended warranty services. The tender required vehicles to feature hydraulic tipping capability, fully sealed cargo bodies, anti-leakage devices, and compliance with Changsha’s operational scheduling requirements for heavy-duty vehicles (i.e., operation permitted outside restricted hours). II. Capacity Selection: Matching Operational Volume—from 3 m³ to 24 m³ The core principle for selecting municipal sludge transport vehicles is: Daily workload × Transport distance ÷ Single-trip capacity per vehicle = Required number of vehicles. Taking this Changsha project as an example: approximately 200 tons of sludge must be transported daily over a one-way distance of ~15 km (including entry/exit time), with each round-trip cycle taking ~1.5 hours (including loading/unloading, driving, and waiting). Thus, each vehicle can complete 8–10 trips per day. The table below compares matching performance across different capacities under similar operating conditions (based on Chengli’s product database and procurement practices across various regions): Vehicle Capacity | Reference Model (Chengli Announcement) | Payload per Trip (tons) | Daily Output per Vehicle (tons) | Vehicles Required to Handle 200 Tons | Applicable Scenario ---|---|---|---|---|--- 3 m³ | CLW5030GXWD6 | ~2.5–3 | 20–30 | 7–10 units | Small-diameter sewer networks, narrow alleys 5 m³ | CLW5070GSSD6 | ~4–5 | 35–50 | 4–6 units | Street maintenance, small transfer stations 8 m³ | CLW5180GSSD6 | ~7–8 | 60–80 | 3–4 units | District-level sanitation offices, medium-sized stations 12 m³ | CLW5180ZLJD6 | ~10–12 | 80–120 | 2–3 units | Large transfer stations, wastewater treatment plants 24 m³ | CLW5250ZLJZ6 (Sinotruk chassis) | ~20–22 | 160–220 | 1–2 units | Large-scale wastewater treatment plants, long-distance transport Note: Models listed are Chengli’s official announcement models; actual configurations follow tender specifications. Daily output estimates assume 8–10 trips/day and 85% average payload utilization. As shown above, for a daily workload of 200 tons and transport distances ≤15 km, only 1–2 units of the 24 m³ model are needed—significantly reducing fleet size, driver costs, and parking space requirements compared to 6–8 units of the 5 m³ model. This efficiency gain is the primary rationale behind Changsha’s selection of the 24 m³ solution. III. Winning Bid Interpretation: Sinotruk Chassis + Chengli Body Key configuration elements of the winning bid are as follows: Chassis: Sinotruk HOWO series, wheelbase ~4,600 mm, engine power ~350 hp, China VI emission compliant, equipped with OEM power take-off (PTO) and air conditioning. Body: Manufactured by Chengli Special Purpose Vehicle Co., Ltd., fully sealed body (body wall thickness: 4