Case Study: Joint Procurement of 3308-Series Sewage Treatment Vehicles by Multiple Districts in Shenzhen — An Efficient Solution for Humid and Hot Environments. In this rapidly developing city, municipal sanitation departments face dual challenges of sewage treatment and rain-season sediment removal. In 2025, a municipal sanitation department collaborated with several surrounding districts and counties to launch a centralized procurement project for the 3308-series sewage treatment vehicle (model EHY5045TWCE6), aiming to address the increased frequency and complexity of sewage treatment under humid and hot climatic conditions. Below is an analysis—based on publicly available tender information—of the joint procurement background, technical standard formulation, centralized tendering process, and Chengli Special Purpose Vehicle’s supply solution. Joint Procurement Background: Humid-Hot Climate and High-Load Operational Demands Shenzhen is located in South China, experiencing frequent rainy seasons and high humidity, with over 150 precipitation days annually. Conventional sewage treatment vehicles often suffer from elevated failure rates in high-temperature, high-humidity environments due to insufficient anti-corrosion coatings and premature sealing component aging. A survey conducted by the municipal sanitation department revealed aging sewage treatment infrastructure across multiple districts and counties within its jurisdiction, creating an urgent need to replace aging fleets with new vehicles offering superior corrosion resistance and high-efficiency operational capability. The joint procurement model—standardizing technical specifications across participating regions—reduces procurement costs while ensuring stable vehicle performance during high-load rainy-season operations. According to publicly disclosed tender documents, the total procurement budget was capped at approximately RMB 5.561 million, covering five units of the 3308-series sewage treatment vehicle, with an estimated unit price of around RMB 1 million. Tender requirements explicitly stipulated that vehicles must feature anti-corrosion coating treatments, sealing components resistant to humid-heat aging, and suitability for high-frequency operation during Shenzhen’s rainy season. Unified Technical Standard Formulation: Focus on Corrosion Resistance and Sealing Durability To address Shenzhen’s humid-hot environment, technical standards were specifically developed around corrosion resistance and sealing component durability. Based on MIIT-approved parameters (e.g., mature technologies applied to models such as CLW5070GSSD6), Chengli Special Purpose Vehicle established the following key specifications for the EHY5045TWCE6: • Anti-Corrosion Coating: Epoxy zinc-rich primer + polyurethane topcoat; salt-spray resistance ≥1,000 hours—suitable for Shenzhen’s coastal high-salt-fog environment. • Sealing Component Durability: Fluoroelastomer (FKM) material selected; operating temperature range: −20°C to +200°C; anti-aging service life ≥5 years—ensuring leak-free operation under high-rainfall, high-humidity conditions. • High-Load Performance: Engine power ≥85 kW; sewage tank capacity: 4.5 m³; single-operation cycle time ≤30 minutes—meeting the demand for frequent use during rainy seasons. These standards align with local procurement practices and have been validated through third-party testing reports, ensuring long-term reliability under humid-hot environmental conditions. Centralized Tendering Process: Analysis of Chengli’s Winning Bid The tender employed open competitive negotiation, attracting participation from multiple special-purpose vehicle manufacturers. Chengli Special Purpose Vehicle secured the contract based on the following competitive advantages: • Direct Factory Sales: Elimination of intermediaries reduces unit cost by approximately RMB 8,000–15,000 compared to 4S-channel pricing, enabling more precise budget control. • Localized Production: Zero-invent