Project Background: Municipal Sewer Cleaning Requirements and Procurement Challenges in a District of Hangzhou. In 2025, the municipal sanitation department of a district in Hangzhou launched its annual procurement plan for sewer cleaning equipment to address siltation issues in aging urban pipelines. According to publicly released tender information, the budget was capped at approximately RMB 330,000, with the objective of procuring one Dongfeng double-cab sewage suction truck featuring an effective tank capacity of about 3 cubic meters. The vehicle must comply with blue license plate regulations (drivable with C-class driver’s license) and be capable of operating within residential communities and narrow alleys. A core challenge stems from Hangzhou’s location in China’s Jiangnan water town region—characterized by an annual average rainfall exceeding 1,400 mm—resulting in fully loaded pipeline systems during the rainy season. Consequently, the sewage suction truck must operate reliably under high-frequency, long-duration conditions in hot-humid environments, imposing stringent requirements on corrosion resistance, seal durability, and continuous operational reliability. After multiple rounds of technical proposal evaluation and on-site inspections, the client ultimately selected the Dongfeng double-cab sewage suction truck (model CLW5070GSSD6, chassis-modified) manufactured by Chengli Special Purpose Vehicle Co., Ltd. This model is built upon the Dongfeng DOLICA chassis, with a wheelbase of 3,308 mm, powered by a Quanchai Q23-136E60 engine (China VI emission standard), delivering a rated power of 100 kW and peak torque of 320 N·m—fully compliant with blue license plate and C1 driver’s license requirements. The tank is fabricated from Q235 carbon steel and internally coated with epoxy resin anti-corrosion paint, effectively resolving tank corrosion issues prevalent in southern China’s high-humidity climate. Additionally, all hydraulic cylinders and sealing components utilize heat- and humidity-resistant rubber materials and undergo a 48-hour salt-spray test prior to delivery, ensuring no aging or leakage during continuous operation—even during Hangzhou’s plum-rain season (with relative humidity frequently exceeding 85%). Post-delivery, the vehicle has been primarily deployed for suction and transport operations targeting rainwater pipelines, septic tanks, and riverbed sediments across urban areas. According to customer feedback, during the typhoon season from July to September 2025, the vehicle operated continuously for over 120 hours without experiencing hydraulic system leakage or electrical failures. Its single-load cleaning capacity reached approximately 2.8 tons, improving operational efficiency by roughly fourfold compared to traditional manual methods. This case subsequently attracted attention from multiple cities across Zhejiang Province and has become a benchmark reference for cross-regional procurement replication. Procurement Solution Interpretation: Alignment Between Tender Requirements and Chengli’s Proposal In this government procurement project, the tender document specified the following key technical requirements—all of which were fully addressed by Chengli Special Purpose Vehicle through certified parameters and customized configurations: Tender Requirement | Chengli Solution (Based on CLW5070GSSD6 Certification) | Advantage Analysis Chassis: Dongfeng double-cab, blue license plate (C-class license), gross vehicle weight ≤ 4,495 kg | Dongfeng DOLICA double-cab cab, wheelbase 3,308 mm; curb weight 2,865 kg; rated payload 1,500 kg; gross vehicle weight 4,495 kg | Fully complies with new blue license plate regulations; drivable with C1 license; unrestricted urban access Effective tank volume: 3 cubic meters | Certified tank volume: 3.2 cubic meters | Meets tender requirement with margin—enhancing per-trip operational efficiency Corrosion protection: Suitable for high-humidity environments; internal tank sur