case study:
REPAIRING DETERIORATING SEWER SYSTEMS IN HONG KONG

📄 ARTICLE EXCERPT

When Hong Kong's Drainage Services Department needed a lasting solution for their deteriorating sewer infrastructure — spanning 900 miles of pipelines and 280 treatment facilities processing 700 million gallons daily — they turned to ArmorThane's advanced polyurea spray coating technology. Our team delivered a complete manhole rehabilitation solution that eliminated deterioration, strengthened structural integrity, and provided decades of corrosion resistance, all completed within a one-month timeline.

⚡ QUICK SUMMARY

Hong Kong Sewer Rehabilitation Case Study

From aging infrastructure challenges to a cutting-edge polyurea solution — discover how ArmorThane restored Hong Kong's critical sewer system with advanced spray coating technology that delivers permanent protection.

→ Project Brief → Getting Approvals → Application Process → Case Details → Other Cases → Get Help

PROJECT BRIEF

For Hong Kong, like other densely populated areas, handling sewage is a challenge, especially with an aging infrastructure. The network involves about 900 miles (1,448 km) of pipelines going to 280 treatment facilities, processing over 700 million gallons (2.6 billion L) of sewage per day. Maintenance is critical and ongoing.

Instead of patching existing problems or completely rebuilding manholes and other parts of the system, we proposed a long-term solution using our polyurea spray coating method to stop deterioration and strengthen walls. This entailed working with a contractor who did pipeline repair in the region.

⭐ PRO TIP

Polyurea spray coatings are the gold standard for sewer rehabilitation because they cure in seconds, forming a completely seamless monolithic barrier. Unlike traditional patching or relining methods that rely on joints and seams, polyurea eliminates the #1 failure point in sewer infrastructure — making it the most cost-effective long-term solution for municipal wastewater systems worldwide.

GETTING APPROVALS

To earn approval from government officials, Rob Anderson in our USA headquarters flew to Hong Kong to demonstrate the process and define results. While the contractor had air compressors and generators that were compatible with the local electrical systems, they did not have spraying units needed for this project. We retrofitted and shipped high-speed, high-pressure coating equipment and product from the U.S. facility. It required 380 volt, three-phase wiring and a transformer box. Everything was then mounted on a flatbed truck for mobility.

🔍 DID YOU KNOW?

Hong Kong's sewer network processes over 700 million gallons (2.6 billion liters) of sewage every single day — enough to fill over 1,000 Olympic swimming pools. With 900 miles of pipelines connecting 280 treatment facilities, even a small improvement in infrastructure durability can save millions in maintenance costs annually. Polyurea coatings typically last 30+ years without requiring retreatment.

APPLICATION PROCESS

The two-component polyurea coating involves heating and spraying. Our high-speed, high-pressure HighLine equipment provides the control needed for successful results. The chemical reacts quickly to form a seamless protective barrier. A second coating was applied to yield an approximate total thickness of 120 mils.

HighLine polyurea outperforms other coatings because it does not crack even as the conditions cause the surface to expand and contract. It is extremely resistant to corrosive chemicals and temperature change.

During project approval, Anderson demonstrated processing chemicals and gun operation for maximum control and performance to local applicators. Then they trained by spraying felt samples to gain experience with the equipment before working on a manhole.

Actual spraying of one manhole takes about four hours. The total time for each is one to two days depending on the size and deterioration of the manhole. This allows for all of the steps involved in cleaning, drying, repairing, spraying and curing.

Moving forward, 40 manholes were scheduled for maintenance.

🎯 KEY TAKEAWAY

A single manhole rehabilitation takes approximately one to two days depending on deterioration level, with actual spraying completed in about four hours. The two-component polyurea system forms a seamless 120-mil barrier that resists cracking, corrosion, and extreme temperature changes — delivering permanent protection that traditional patching methods simply cannot match.

The applicator ended the project by conducting tests on the polyurea applied substrate. This involved affixing 20mm dollies to the surface. After allowing the glue to set for 24 hours, the dollies were then drilled using a 20mm coring hole bit.

“Because sewers are a grid of underground tunnels that carry waste throughout the city to the treatment facilities, there are always a number of challenges facing the task,” says Anderson. “And, Hong Kong was no exception.”

Case Details

Client Details

Drainage Services Department - HK

Service Provided

Stop deterioration and strengthen sewer manhole walls using polyurea.

Project Timeline

One month

QUICK FACTS

Location Hong Kong, China

Network Size 900 Miles

Treatment Facilities 280

Daily Volume 700M Gallons

Coating Thickness 120 Mils

Manholes Scheduled 40

Spray Time/Manhole ~4 Hours

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Hong Kong repairing deteriorating sewer systems

Summary of polyurea spray coating project for sewage systems

Protective maintenance on a manhole using ArmorThane's infrastructure repair solutions.