Recently, multiple plateau-specific environmental water treatment equipment of China Railway Environment under China Railway Hi-Tech Industry have been successfully put into operation for plateau railway projects, including integrated domestic sewage treatment equipment with a daily treatment capacity of 40 cubic meters and 65 cubic meters, as well as a tunnel wastewater treatment system with a treatment capacity of 200 cubic meters per hour, fully meeting the full-scenario sewage treatment demands of project living and construction areas.

Tackling Cold Alpine Challenges to Ensure Stable Standard Discharge of Domestic Sewage

Plateau regions feature high altitude and extreme environments with long-term low temperature, low oxygen and low air pressure, which greatly reduce the activity of microorganisms in water. Traditional sewage treatment equipment generally suffers from unstable operation and substandard effluent quality.

Targeting the above pain points, China Railway Environment carried out special technical research and developed customized plateau-type integrated sewage treatment equipment. Adopting an enhanced biological coupled filtration process, the equipment effectively solves the technical bottleneck of insufficient biodegradation efficiency in low-oxygen and low-temperature environments, and maintains stable operation even under extremely harsh conditions. The treated water is clear and up to standard, and can be directly reused for construction site dust suppression, site greening and vehicle washing, realizing recycled utilization of water resources at the construction site and fully practicing the construction philosophy of green construction, energy conservation and consumption reduction.

Integrated and Efficient Technology Breaking the Dilemma of Tunnel Wastewater Treatment

Gushing water from plateau railway tunnel construction is characterized by high suspended solids content and large fluctuations in water pH value. The fragile plateau aquatic ecosystem is difficult to restore once polluted. In addition, the narrow and limited construction site makes traditional large sedimentation tanks occupy large land area and difficult to layout, which cannot adapt to on-site working conditions.

Faced with the dual challenges, the tunnel wastewater treatment system developed by China Railway Environment integrates multiple technologies to form a compact and efficient integrated treatment solution. Sewage first passes through a cyclone sand settling device to remove large particulate impurities, then enters the core clarification unit. By virtue of the collaborative processes of sludge reflux, cyclone coagulation, micro-vortex flocculation and contact filtration, efficient sedimentation of pollutants is realized. Compared with traditional horizontal flow sedimentation tanks, the equipment improves sedimentation efficiency by more than 50% and treatment capacity by 3 to 5 times, while occupying only one quarter of the land area of traditional equipment, perfectly adapting to narrow construction sites. The sewage is further deeply purified by a drum microfiltration machine, and the effluent meets dual water quality standards for railway reuse and urban miscellaneous use, realizing on-site reuse of clean water and compliant discharge of tail water, and fully safeguarding the ecological security of plateau river basins.

Full-process Closed-loop Disposal to Guard the Ecological Bottom Line of the Plateau

In the solid waste treatment link, the entire water treatment system realizes a complete closed-loop disposal. The project is equipped with drum-type sludge thickening and dewatering integrated equipment for centralized disposal of sludge generated from sewage treatment, reducing the sludge moisture content from over 95% to 75%~85%, greatly cutting down sludge volume and transportation and disposal costs, eliminating secondary pollution at the source and realizing reduction and harmless treatment of construction sludge.

From domestic sewage purification and tunnel wastewater treatment to water resource recycling and closed-loop sludge disposal, the complete plateau water treatment system of China Railway Environment realizes standardized full-process disposal, ensuring all sewage is fully collected and scientifically treated, and achieving coordinated development of engineering construction and plateau ecological protection. Up to now, more than 80 sets of domestic sewage and construction wastewater treatment equipment have been put into service for construction projects in plateau areas.