Successful Trenchless CIPP Lining of DN1800 Sewer Installation in Wenzhou

Case Study: Trenchless UV Curing Rehabilitation for Large-Diameter Underground Drainage Pipe in Wenzhou, Zhejiang

Project Overview:
In March 2025, a challenging trenchless sewer rehabilitation project was successfully completed in Wenzhou, Zhejiang, involving the UV CIPP lining of a DN1800 underground drainage pipe. The project was executed using advanced UV curing technology, ensuring minimal disruption to the surrounding area while restoring the structural integrity of the large-diameter sewer pipeline.

Key Challenges:

• Extra-Large Pipe Diameter (DN1800): The massive 1.8-meter sewer pipe required specialized trenchless pipe lining techniques.

• Heavy Material (Approx. 10 Tons): Transporting and installing the UV-cured CIPP liner demanded precision due to its weight.

• Buried Depth (3 Meters): The moderate burial depth required careful handling to avoid surface disturbance.

• Non-Disruptive Construction: As an urban drainage repair project, minimizing road closures and environmental impact was critical.

Solution: UV CIPP Lining by Daoyunai Energy-Saving Technology
The rehabilitation used a high-strength UV-cured liner manufactured by Daoyunai Energy-Saving Technology (Suqian) Co., Ltd., a leader in CIPP pipe repair materials. The 90-meter-long liner was carefully inserted and then cured in place using UV light technology, creating a seamless, corrosion-resistant new pipe within the old one.

Execution Process:

1. Pipe Inspection & Cleaning: Prior to lining, the sewer pipe was inspected and cleaned to ensure optimal curing.

2. Liner Installation: The 10-ton CIPP liner was pulled into the DN1800 pipe using a winch system and crane.

3. UV Curing Process: A UV light train was deployed to harden the resin, forming a durable, jointless pipe.

4. Quality Testing: Post-curing, the new pipe was inspected via CCTV sewer camera to confirm a perfect fit.

Results:

• Fully Restored Pipeline: The trenchless pipe repair extended the lifespan of the municipal drainage system without excavation.

• Cost & Time Efficient: Compared to traditional dig-and-replace methods, UV CIPP lining saved both time and budget.

• Zero Surface Damage: The no-dig sewer repair prevented road closures and traffic disruptions.

Why This Method?

• Best for Large Pipes: UV-cured CIPP is ideal for big-diameter sewer rehabilitation (DN1200+).

• Long-Term Durability: The new liner resists corrosion, roots, and cracks, reducing future maintenance.

• Eco-Friendly: No excavation means lower carbon footprint—ideal for sustainable urban drainage solutions.

Conclusion:
This DN1800 sewer pipe rehabilitation in Wenzhou demonstrates the effectiveness of trenchless UV curing technology for large-scale municipal drainage repairs. By partnering with Daoyunai Energy-Saving Technology, the project achieved a fast, durable, and non-disruptive solution, setting a benchmark for underground pipe rehabilitation in China.