I. Project Background: From Initial Procurement in 2022 to Contract Renewal in 2024 In early 2022, a municipal sanitation department in Ma'anshan launched a procurement initiative for compact sewage treatment vehicles to address insufficient local sewage treatment capacity. Following a public tender process, Chengli Special Purpose Vehicle Co., Ltd. (hereinafter referred to as "Chengli") delivered three Dongfeng Yizhan-style sewage treatment vehicles (model: CLW5070GSSD6), each priced at approximately RMB 280,000, with the total budget controlled within RMB 1,033,000 (per publicly available tender information). These vehicles are primarily used for sewage suction, transportation, and preliminary treatment in urban old residential communities and industrial parks, covering approximately 15 operational sites. In 2024, the department initiated another procurement round, renewing the contract and expanding the order to five units of the same model. The unit price increased slightly to approximately RMB 290,000, bringing the total budget to about RMB 1,664,000 (based on local procurement practices). The core reason for renewal was the outstanding performance of the initially procured vehicles during two years of actual operation—particularly under low-temperature winter conditions—without any downtime caused by cold-start failures or hydraulic system malfunctions, significantly enhancing operational efficiency. II. User Feedback: Cold-Start Reliability and Low-Temperature Hydraulic Stability Are Critical Ma'anshan lies in the Jianghuai region, where winter temperatures can drop to -8°C to -12°C, imposing stringent requirements on specialized vehicles’ freeze resistance and hydraulic system adaptability at low temperatures. The department reported that the CLW5070GSSD6 sewage treatment vehicle supplied by Chengli—built upon a Dongfeng chassis—incorporates several targeted design features: Cold-Start System: Standard equipment includes a low-temperature preheating device and antifreeze coolant circulation system, ensuring successful first-time engine start even at -15°C. Over two winter seasons, zero cold-start failures were recorded. Low-Temperature Hydraulic Stability: The hydraulic system employs low-temperature-resistant sealing components and low-pour-point hydraulic oil, combined with insulated, thickened hydraulic lines. Manual operation remains smooth even at -10°C, with no oil leakage or component jamming observed. Winter Maintenance Program: Chengli provides proactive maintenance services, including one free quarterly inspection, replacement of winter-grade engine oil and filters, and 24-hour emergency response support. The department noted that maintenance costs are approximately 20% lower than those of competing brands. Additionally, the vehicle’s 4-cubic-meter sewage tank (approx. 4,000 L capacity) and dual-stage vacuum pump maintain stable suction efficiency under low temperatures, reducing average single-operation time from 40 minutes to 28 minutes—a productivity improvement of roughly 30%. III. 2024 Contract Renewal and Expanded Procurement: Decision Basis and Comparative Data The 2024 contract renewal resulted from a comprehensive evaluation based on two years of real-world usage data. Through comparative analysis, the department decided to expand procurement, establishing the following decision criteria: Comparison Dimension Chengli Dongfeng Yizhan Model (CLW5070GSSD6) Competitor A (Same Price Range, 2022 Comparison) Competitor B (Same Price Range, 2022 Comparison) Cold-Start Success Rate at -10°C 100% 85% 90% Annual Low-Temperature Hydraulic System Failure Rate 0 times/year 2–3 times/year 1–2 times/year Annual Maintenance Cost (Including Labor) Approx. RMB 12,000 Approx. RMB 18,000 Approx. RMB 15,000 Single-