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Case Study

K-water, Tongyeong City South Korea

K-water, the national bulk water utility in South Korea, supplies water across the country to smaller cities and controls everything from collection, treatment and pumping to maintenance, inspection and rehabilitation of the nation-wide pipeline system.

In addition to supplying treated water to these small cities, many have contracted K-water to manage and maintain their distribution systems as they battle the challenges of aging infrastructure. Beginning in 2011, K-water has used Sahara® Leak Detection to address non-revenue water and collect condition information about its metallic pipelines.

Project Details

Services
Sahara® Leak Detection
NRW reduction program
Baseline condition assessment
Timing
2012-ongoing
Pipe Material
Steel, Cast Iron, Ductile Iron
Diameter
6-inch (150mm) to 90-inch (2300mm)
Transmission Type
Water

Project Highlights

22 leaks located in 25 miles (40.23 kms) of inspection

Pinhole leaks identified within 5 cm of actual location

Estimated 350,400 m3 of water saved per year in Tongyeong City

Challenge

In 2009, K-water was searching for a large-diame­ter leak detection tool for its critical trunk mains. While K-water has done an exemplary job of maintaining its nation-wide pipeline network, which totals about 5,000 kilometers and has a Non-Revenue Water (NRW) rate of about 2 per­cent, many of its client municipalities suffer from high levels of NRW as their infrastructure ages and begins to leak. K-water was also interested in a tool that would allow them to compare actual pipeline conditions with their extensive pipeline engineering knowledge, allowing for quality con­dition assessment and failure prevention. In 2011, K-water began a knowledge-transfer program with Pure Technologies to become independent operators of Sahara leak detection.

Solution

K-water has built up expert knowledge in pipe­line engineering, a database of information on their pipe materials and pipe failure methods, and has adopted the best condition assessment technologies in the market to help inspect their pipelines so that efficient, prioritized rehabilita­tion and replacement plans can be made.

One condition assessment tool K-water has adopted is the Sahara platform – a tethered system with acoustic leak detection and inline video. While many utilities around the world use this tool for large-diameter leak detection, K-wa­ter has adopted it in an innovative way, choosing to use it as a complete condition assessment tool to provide information on its pipelines and accu­rate location of leaks.

The tool is non-destructive and is pulled by the flow of water by a small drag chute. When the sensor is inserted into a tap, it remains tethered to the surface to allow for immediate checking of suspected leaks and gas pockets, internal pipe wall conditions and pipeline features by winching the sensor back and forth from the surface. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations. Sahara also provides real-time inline video, which allows the operator to see live pipe conditions as the tool surveys for leaks and gas pockets.

Operating with a national mandate and several stakeholders, K-water faces a number of logistical challenges with its pipeline infrastructure.

One challenge is population density; South Korea is roughly 2 per cent of the size of Canada with almost double the population, meaning large, densely populated regions rely on K-water for consistent water service. A failure or service interruption to a critical trunk main could be disastrous K-water’s credibility with customers.

South Korea is also a very mountain­ous region, meaning pipelines supplying water throughout the country often pass through areas that are difficult to inspect using traditional methods. In addition to the landscape, many of K-water’s large diameter pipelines are buried deep in the ground, making excavation projects com­plex and expensive to complete.

By becoming certified Sahara tool operators, K-water staff can deploy the tool at their own descretion and are able to overcome these chal­lenges to complete inspections in difficult regions.

Results

Tongyeong City, South Korea, which has a high NRW and features 32-inch (800-mm) steel pipe, has been inspected twice; first as part of Pure’s Sahara training program and subsequently by K-water as an independent operator. The inspec­tions in Tongyeong City were extremely success­ful, locating 10 total leaks with high accuracy in 2.5 kilometers of inspection for an estimated sav­ings of 350,400 cubic meters of water per year.

During the training inspections, Pure and K-wa­ter were able to locate pinhole leaks as close as 5-cm above and below the actual leak location – meaning service disruption, excavation and repair times were minimal. In K-water’s subsequent inspection of the same pipeline in Tongyeong City, they were able to excavate and repair all three identified leaks in 5.5 hours each during the night (3 separate repairs), causing little disruption to customers.

In total, K-water has inspected 25 kilometers of pipeline and located 22 leaks of varying sizes. K-water has inspected both its own pipelines as well the regional pipelines that it operates and has covered pipes with diameters as small as 150-mm and as large as 2300-mm, with most pipe being either steel, ductile iron or cast iron pipe. K-water’s 2012 program will cover about 52 kilometers of pipeline for leaks and gas pockets

While the tool has been effective in locating leaks for K-water, its value as a complete condition assessment tool has also been helpful due to the unique challenges faced in South Korea. K-water has been able assess the state of its pipelines by combining the inline video data and its extensive engineering knowledge. By doing this, K-water has become a thought-leader in large-diameter pipeline management.

K-water has successfully applied the Sahara platform for condition assessment in its transmission mains and for leak detection in municipal trunk mains.

Se-Hwan Kim

General Manager, Water Supply Operation & Maintenance Department, K-water

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