Like many utilities, United Water New Jersey (UWNJ), a subsidiary of United Water, was concerned about being able to identify transmission and distribution main leaks. However, its field crews and an outside contractor were having difficulty accurately detecting and locating leaks in larger diameter water mains and sections of pipe that did not have available appurtenances. In an effort to improve water conservation and reduce non-revenue water, UWNJ began evaluating leak detection services with the ability to accurately isolate leaks in large diameter mains.
UWNJ selected Toronto-based Echologics Engineering for a Transmission Main Leak Detection pilot survey. The goal was to assess approximately five miles of water mains composed primarily of Reinforced Concrete Pipe (RCP), pre-stressed cylinder concrete (PCCP), and cast iron pipe (CIP).
A subsidiary of Mueller Water Products, Echologics is a developer of acoustic-based technologies for water loss management, leak detection, and pipe condition assessment. With proprietary sensor and signal conditioning technologies, the company’s system works on all pipes irrespective of diameter, geometry, material, etc. The system also has the ability to assess the structural condition of transmission mains, distribution pipelines, and force mains, including a unique solution for Asbestos Cement pipe.
For the UWNJ pilot, Echologics used acoustic sensors specifically developed for detecting leaks in large diameter mains. Where standard appurtenances are available, such as hydrants, air valves, or blow-off valves, the company’s hydrophones can be installed via any 1.5-inch isolation tap. These require direct contact with the water column and can be separated by wide distances on transmission mains, sometimes as much as 5,000 feet, and still remain effective.
Where no such appurtenances are available or accessible, the company has external sensors specifically designed for transmission mains. These require physical contact with the pipe, and are often mounted in valve boxes or in 12-inch-diameter holes vacuum-excavated to provide access to the pipe wall.
In the UWNJ pilot program, the system discovered a major leak in a 42 inch cast iron water main that runs beneath a river within the test area.
Because the acoustic detection system substantially reduces both electronic “white” noise as well as ambient background noise often created by running water or traffic, it was able to detect and accurately pinpoint the sub-river leak, which was responsible for losing an estimated 100,000 gallons of treated water per day.
As a result, UWNJ was able to repair the leak and avoid potential failure. Eliminating the leak provided immediate savings due to the significant marginal cost of non-revenue water.
“Until we began working with Echologics, finding leaks on large mains was a difficult and costly process,” said Antonio Vicente, Operations Engineer for United Water. “The company’s advanced system as well as its technicians’ expertise helped us to quickly locate a significant leak. The outcome of this project is a testament to the value of UWNJ’s use of advanced services and technology and demonstrates our commitment to optimizing service for both customers and the environment.”
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