In the second half of 2024, a municipal sanitation department in a district of Deyang City planned to procure a batch of National VI emission-compliant sewage treatment vehicles for daily maintenance of old residential area pipeline renovation and stormwater-sewage separation projects. After multiple rounds of evaluation and on-site inspections, the department ultimately selected Chengli Special Purpose Vehicle Co., Ltd.’s Dongfeng 3308 mm wheelbase chassis-based sewage treatment vehicle solution. This article uses this real-world case as a starting point to thoroughly analyze chassis selection logic, load-bearing and off-road capability considerations, maintenance convenience, and interpret Chengli’s winning bid proposal—providing reference for organizations with similar procurement needs. I. Project Background and Requirements Analysis Deyang is located in the northeastern part of the Sichuan Basin, characterized by hilly and plain terrain. Its municipal pipelines were mostly constructed earlier, and some areas suffer from aging pipes and frequent blockages. The sewage treatment vehicles procured in this project are primarily intended for the following applications: - Suction and preliminary solid-liquid separation of sewage from manholes in residential communities and streets; - Rapid dewatering at emergency pipeline repair sites; - Mobile sewage treatment operations integrated into comprehensive sanitation programs. The procuring entity specified several mandatory requirements: the vehicles must comply with National VI emission standards; the chassis must possess sufficient load-bearing capacity to support continuous operation; the wheelbase must not be excessively long to ensure maneuverability on narrow roads in old residential neighborhoods; and maintenance must be convenient—since Deyang lacks numerous specialized vehicle service stations, the chassis must offer nationwide warranty coverage. According to publicly released tender information, the project’s budget was capped at approximately RMB 499,000 (based on local procurement practices at the time), with vehicle configurations focused on sewage treatment vehicles equipped with 4–6 m³ tank capacities. II. Chassis Selection: Is the Dongfeng 3308 mm Wheelbase Optimal? Before analyzing Chengli’s proposed solution, let us first review mainstream chassis options currently available on the market. As one of China’s largest special-purpose vehicle manufacturers, Chengli offers product lines built upon chassis from Dongfeng, Sinotruk, Foton, FAW Jiefang, and Shaanxi Automobile. For the 4–6 m³ sewage treatment vehicle segment, common chassis wheelbases range between 2,800 mm and 3,800 mm, among which the Dongfeng 3308 mm wheelbase (corresponding to the Dongfeng Dorica D6 series) stands out as a classic choice. The table below provides a comparative overview of the applicability of various chassis models for the Deyang project: Comparison Item | Dongfeng 3308 mm Wheelbase (D6) | Sinotruk HOWO 3200 mm Wheelbase | Foton Aoling 3280 mm Wheelbase | FAW Jiefang Tiger VN 3000 mm Wheelbase ---|---|---|---|--- Representative Chassis Model | EQ1075SJ3CDF | ZZ1048G17FB5 | BJ1048V9JDA-AB3 | CA1040P40K61L2BE6A84 Engine Technology | Yuchai / Quanchai National VI | Weichai National VI | Foton Cummins National VI | FAW Power National VI Maximum Gross Vehicle Weight (kg) | 7,360 | 4,495 (light-duty truck limit) | 4,495 | 4,495 Wheelbase Advantage | 3308 mm — excellent balance | 3200 mm — slightly shorter | 3280 mm — close match | 3000 mm — relatively short Applicable Scenarios | 4–6 m³ tanks; all-around performance | <4 m³, light-load applications | 4–5 m³, lightweight applications | <4 m³, short-distance operations Maintenance Convenience | Nationwide warranty network with dense service coverage | Limited service network coverage | Moderate national coverage | Northern region–focused coverage