Wednesday, June 22, 2011

Reducing Cost and Heading Off Disaster
According to Lyn Corum writing at
George Kunkel, labeled by at least one industry insider as the “godfather of leak detection,” has overseen the City of Philadelphia’s leak detection surveys for the past 30 years. It may be the oldest leak detection program in the US....

Kunkel has also served on the American Water Works Association (AWWA) Water Loss Control Committee, which developed the Water Audit Software. This software allows utility users to calculate the dollar value of both apparent and real water losses.
Kunkel says water utilities bury their pipes underground and suffer from the malady, “out-of-site, out-of-mind.” But all pipe systems are going to deteriorate over time and leaks will occur. Most utilities respond with “reactive leakage management”—wait until it breaks, and then fix it. In this case, the utility will miss out on hidden leaks, running site unseen and trickling away, he says. A number of them rupture and become disruptive to other infrastructure, like streets.
Proactive leak management is typified by the philosophy that, “If we could find and repair the leaks, we will minimize the big events,” says Kunkel.

Unfortunately, most utilities don’t do this—he estimates 90% of the utilities in the US are reactive. ...

Kunkel says the majority of utilities are stubborn about change. However, they are paying to produce, treat, and deliver water, and when it leaks away, the utility pays for that non-revenue water. Once the leaks end, operating costs are reduced. Until the utility accounts for that wasted water, they don’t know how much it is costing them.

The Philadelphia Water Department’s acoustic leak detection surveys are conducted by up to five two-man crews every day, day and night, on a distribution network of 3,144 miles of water mains. Kunkel says the department spends over $1 million a year on the surveys. “We can’t get around the system once a year; we average once every three years,” he notes. “In reality, we visit high-leakage areas every year and low-leakage areas every five years.”

Year by year, Kunkel says the department is looking at $2.455 million in cost savings. That represents water that is not being treated and pumped a second time.

The most common technology is acoustic- or soundings-based that pinpoint specific leaks, says Kunkel....

A handful of utilities, like El Paso Water Utilities, are installing permanent listening devices on valves and hydrants to produce around-the-clock information, which speeds up leak detection by years. The listening devices, or loggers, pick up sounds and transmit them wirelessly to a central station. If managers are awake at 2:00 or 3:00 a.m. when the city is relatively quiet, they can hear the leaks....

Kunkel has been involved in devising a new technique called flow management. In an article (cowritten with Reinhard Sturm for the February issue of Journal AWWA), he describes the method as testing a district metered area in combination with advanced pressure management. This is a “predict-and-prevent” approach to achieve and maintain low leakage levels in the area....

The district metered area is a hydraulically discrete part of the water distribution system supplied via inflow points equipped with flow meters. Valves on water mains are closed to form an enclosure fed by one or more supply mains, similar to a pipeline feeding an island. Flow metering in the district metered area does not pinpoint individual leaks, but it gives the capability of obtaining a quantity of the collective leakage occurring. Also, excessive water pressures can be reduced and optimized, helping to mitigate pressure transients. Surprisingly, Kunkel and his partners found that roughly half of the leakage volume comprised background leakage, reflecting poor infrastructure or service connection piping conditions, which cannot be handled by acoustic leak detection.

They concluded that a traditional leak detection and repair campaign could be expected to resolve no more than approximately half of the leakage. Further details of the project should best be read in the Journal AWWA.

Danny Heredia, with WCS Company in El Paso, TX ... understands water utilities’ resistance to leak detection programs. “I was giving them answers they didn’t want to hear about,” he says.... According to Heredia, following a pilot project in 2000, the El Paso Water Utilities became the first utility in the country to install a permanent, automatic, system that monitors the whole water distribution system at all times. The El Paso Water Utilities (EPWU) has 2,400 miles of distribution pipe and produces 107 million gallons of water per day.... According to John Balliew, EPWU water systems division manager, the new leak detection system cost the city $3 million and will pay for itself in about six years.  The department’s pilot project was carried out in 2000, and in 2004 it purchased 5,000 loggers that operate on batteries. It hired WCS to install the loggers on valves, set up the Permalog3 leak detection program for the utility, and monitor the loggers. Another 5,000 loggers were purchased and installed the following year. Close to 100 leaks were identified in the first year, Heredia says, and in the following years the number detected dropped significantly.

Permalog is an advanced leak noise logger developed by Fluid Conservation Systems, headquartered in Milford, OH, and one of the Haima Water Management companies.

El Paso Water Utilities reports it has found 591 leaks in the years since loggers were first installed beginning in 2004. In the first two years of the program, it saved 725 million gallons of water—twice as much as the city golf course uses in one year, Balliew explains. With the information provided by the loggers system, “we’re able to make informed decisions,” he says. For example, is further assessment required? Does the utility want to replace the pipe now or wait 10 years?

The utility has been able to delay capital improvements based on the data provided by the program, and in one case, says Balliew, an aging pipeline that was judged to need complete replacement proved to have five defective joints that could be repaired at a relatively low cost.

The utility compared the results of the pilot project, when 100 loggers were installed, to its traditional method of having an operator use an amplifier and speaker to check the hydrants and valves for leaks. First, it saved time based on the system’s 24-hour-per-day operation. Balliew says it would take two employees 10 years to do what the new system did in two years. The largest leak found was losing 140 gallons per minute, 60 times more than a person typically uses to take a shower, Balliew says. The leak left no trace of its existence on the street surface.

Balliew sees leak detection as an essential part of a water conservation program that addresses the long-term need to be a good steward of water resources. El Paso began its water conservation program in 1991 and has reduced per capita water use from 200 gallons per day to 133 gallons per day in 2010....

The average water system loses anywhere from 10% to 40% or even 50% of its water, according to Dennis Siegert, municipal utilities solutions manager for Johnson Controls.... Tricia Kuse, director of marketing and strategy for energy solutions at Johnson controls, explains that when water is lost in a utility’s water system, it eventually finds its way into sewage systems and must be cleaned and pumped for a second time. This leads to lost revenue.... Siegert says more and more states are mandating that utilities have water loss programs. Texas has a soft mandate that utilities are required to get their non-revenue water loss to 15%. “We offer services to utilities by providing free audits using AWWA’s audit software,” he says.... The City of Kingsport, TN, contracted with Johnson Controls in 2008 to install an automated meter reading and permanent leak detection system. At the time, the city estimated it was losing more than 1.2 million gallons of water a year to leaks. In the following two years, it found 49 line leaks and breaks. After repairing the pipes and eliminating the leaks the city prevented more than 1,685 gallons per minute of treated water from being lost....

By Lyn Corum
July-August 2011

No comments:

Post a Comment