SUEZ solves big data problem with magnetic flow meters

SUEZ operates regulated water systems in eight US states, and provides contract services to over five million people. SUEZ operates several water systems in the suburbs of New York, including SUEZ New Rochelle and SUEZ Westchester in Westchester County, New York.

Like many older communities, their infrastructure is ageing and in need of repair. Infrastructure improvement is a critical part of SUEZ’s strategic objectives for these water systems and the company is committed to making proactive capital investments.

SUEZ needed greater visibility into its water usage and flow so that the company could minimise water losses. The critical problems SUEZ wanted to solve were water leaks caused by line breaks in the water mains, and water theft by contractors and others. A big main break can waste millions of litres of water, since the time it takes for the leak to surface could be weeks or even months, according to Nick Curcio, manager of non-revenue water for SUEZ. In addition, contractors often — illegally — open hydrants to fill their water tank trucks. Since SUEZ buys water wholesale, water loss from line breaks and theft goes straight to the bottom line, driving up costs for customers and creating potential safety issues.

SUEZ began by closing interties between systems and routing water to locations where it could be measured more easily. “We broke the systems down into smaller zones,” said Curcio. “We wanted to minimise closed valves, and made sure that no unmetered water crosses the boundaries between systems.” They called these zones DMAs or District Metered Areas. Water flow into and out of the DMAs is to be measured and uploaded to the system operating model.

The company created a big data-driven proprietary model of its water systems using historical data to determine baseline water usage in each main, in each zone, in each system. It used as-built data to build a hydraulic model of the system and analysed the historical data for usage against the hydraulic model. In order to compare real-time water usage to the baseline water usage  developed from history, SUEZ needed a way to economically measure water flow and pressure at the boundaries of each zone in the systems. “These water flow meters and pressure transmitters needed to be rugged, durable, and able to operate in no-power situations during storms and power outages, to continue delivering data to the model,” said Keith Kolkebeck, director of technology solutions for SUEZ. “We knew we needed a battery-operated solution.”

Kolkebeck and the SUEZ staff searched for devices that could meet those criteria, and determined that the Siemens Sitrans FM MAG8000 would work as the heart of the system. The Sitrans FM MAG8000 is designed for low-power applications like distribution systems and agricultural irrigation systems. It is designed to have excellent performance at very low flows, and high accuracy at the upper end of the flow range.

The transmitter can be remotely mounted. This, according to Kolkebeck, was an important feature, because of the difficulty of entering a manhole located in the street. The meter body can be mounted in the main running under the street, but it isn’t usually necessary to enter the manhole. In some cases, Kolkebeck said, the meter body was direct buried, with no manhole. Stopping traffic and working in the middle of the street is dangerous, and field personnel appreciate not having to do it.

The flow transmitter, the 10-year life expectancy battery, and the cellular data logger and cellular modem are mounted on a standard backpanel. Instead of being installed in a cabinet, the backpanel is installed on a set of slide brackets in a footpath-mounted meter vault (the same sort of meter vault a large household water meter would be mounted in). The SUEZ technician flips open the meter vault lid and pulls the backpanel up and onto the sidewalk for inspection, maintenance or repair. It is not necessary to block the street or stop traffic to do any expected maintenance including changing the battery. Putting the devices on the backpanel in a meter vault instead of a standard cabinet also reduces the potential for vandalism, since nobody can see what’s in the vault.

Using the Sitrans FM MAG8000 conical flow tube design, and the Siemens sizing program, Curcio said that SUEZ was able to use the smallest meter size possible in each application. This improved the low flow accuracy to the point that, on a minimum flow day, the installed meter accuracy was 2% of rate, and on an average flow day, the accuracy improved to better than 1% of rate, installed. Siemens’ collaboration with SUEZ was critical to fine-tuning the accuracy of the input to their hydraulic model.

The flow meter measures flow and the data is stored in the wireless data logger at one-minute intervals. Once a day, the data logger’s cellular modem uploads the day’s data to the SUEZ SQL Server enterprise database, called EOps, a proprietary program with database that is SUEZ’s meter data management system.

Curcio said that they started with 26% water losses in New Rochelle and 28% in Westchester, so it was essential that SUEZ got a handle on stopping the losses. “With the data from the flow meters, we can see water used, consumed or lost in the EOps system,” said Curcio. The data has been able to pinpoint leaks that were previously thought to be simply part of the usage baseline. “A spike in usage indicates a leak, and the flow data is fed back to the model to triangulate where the leak is.”

“We are finding leaks in hours, not days,” Curcio continued. “Our standard time-to-fix is now less than 24 hours, where it might have taken several days before. The meter data allows us to pinpoint leaks to within a few feet. This means less time digging up the street and a faster time to repair.”

The time the leak happens to the time the leak is found and then repaired has also been shortened. In some cases it is only minutes. A 30 cm main flowing at 3 m/s produces around 12,800 L/min of flow. If it takes 25 hours to find the leak, the lost water will be over 19 million litres.

Lost water is also an energy issue, not just a production issue. It requires energy to pump the water into the distribution system. Reducing water leaks and water theft also reduces the amount of energy necessary to operate the system. It permits SUEZ to operate pumps at off-peak times, further saving electricity.

According to Curcio, a 1 million gallon (3.8 million litre) leak in New Rochelle is roughly equal to 5% of production. Finding and repairing a leak like this is critical. Curcio said that the savings in New Rochelle in previously lost water have been over a million gallons a day. Westchester’s results are similar.

Eventually, Curcio sayid, they will want to move to a fully integrated GIS (geographic information system) database that is further integrated with the enterprise database, EOps. They expect to be able to use the GIS system to pinpoint leaks and water thefts with even greater precision than the current system can. It is certain that the SITRANS MAG8000 will be an important part of the system going forward.