The new initiative restores old iron and steel pipes

Hundreds of kilometers of pipes that Thua Thien Hue Water Supply and Sewerage Company are using are 40-80 years old. Due to poor quality, they cause water turbidity, often causing breakage of pipes or opening of the mouth, both dehydrating and contaminating the tube. A research team of the company had a cheap recovery solution instead of buying a new one.

The rusted water supply pipes when used often cause heavy losses.( Photo of the research team )

Cast iron pipes, steel without internal cement coating (including zinc coated pipes), after long periods of contact with water, especially in the presence of residual chlorine disinfectants in water, or when salty tap water will make the inner oxidation process of the tube increase rapidly, creating a porous layer in the lumen, causing turbid water and high iron content.

In addition, the old iron and steel pipe type often uses slurry connections with cement and wire days (hard joints) so when being affected by external forces, such as cars passing by, the ground is not stable . often suffer from incidents that cause widespread water loss, or cause leakage at the joint. Cloudy and dirty water also makes the clock run slowly and quickly, causing water loss.

Rust water pipe (left) and after treatment (bottom, right).( Photo of the research team )

Engineer Truong Cong Nam and colleagues studied and found that it is possible to clean the surfaces in these tubes with a high-pressure sprayer. Then, the tube is completely cleaned, to reveal the bright surface of cast iron and steel inside.

To protect the surface of the pipe after cleaning, the group uses centrifugal force at high speed to rinse a layer of cement mortar into the tube. After the maintenance process, engineers continue to use bitumen to protect the outer surface of the tubes before putting them into use.

Finally, the research team designed a cemented pipe connecting the pipe, designing a rubber roll to replace the hard joint.

The initiative has helped to double the pressure tolerance of pipes (from 8 kg / cm3 to 16 kg / m3), while improving the quality of water supply and preventing water loss, instead of removing it for construction. new pipelines. The solution also prevents outside dirty water from entering the tube through leaks.

The rehabilitation of old pipes has helped the company proactively replace over 90 km of poor quality old pipes, clearly improving the quality of water supply in Hue city and surrounding areas. The rate of water loss from 26% in 2000 to below 20% as the current level.

Generally, the solution saves nearly VND 12.25 billion from replacing old and poor quality pipelines; benefit of about VND 8.8 billion due to lowering the annual water loss rate compared to 2001; improve pipe pressure, minimize the number of piping incidents; take advantage of old, poor quality pipes.

According to Mr. Nam, this technical solution can be applied to all water supply companies nationwide, especially companies with old water supply systems. The project won the second prize in the national technical innovation contest 2005.

Thuan An