SPRINGDALE -- The Water Department has been working to prevent corrosion on the pipes moving fresh water from the tanks to customers throughout the city.
"It's not the sexiest or most expensive project we've done, but it's probably the most important," said Heath Ward, executive director of Springdale Water Utilities.
Science lesson
Municipal water systems consist of pipes made of steel, galvanized steel, copper, concrete and sometimes plastic. Buried pipes are exposed to water in the soil and can corrode, or rust.
Corrosion occurs when the naturally occurring minerals present in the water and the oxygen in the water react with the pipe. Just like leaving an unpainted piece of metal out in the rain and sun, it will rust. This means the electrons on the surface of the metal are removed — the metal is oxidized and rusted.
To help slow corrosion in municipal water pipes, there are some “tricks” that can slow the removal of electrons from the surface of the pipes, said Leslie Pittman of the Springdale School District.
“It’s as simple as attaching a piece of metal to the pipe that can lose electrons easier than the pipe can. This piece of metal is called a sacrificial anode,” she said. “The sacrificial anode will actually be eaten away before the pipe will begin to rust. This is how easily it can give away its electrons.”
The price of fixing a broken water main is $3,000 to $5,000. The replacement of a used anode is about $150, Pittman said.
Source: Staff report
By the numbers
Springdale Water Utilities
• 35,000: Number of customers
• 600: Miles of water pipe
• Less than 500: Miles of sewer pipe
• 18 million gallons: Average water use per day in system
• 14 million gallons: Average waste water per day
• 100 gallons: Average water use per person per day
• 32 million gallons: System capability per day
• 24 hours: Water supply at tank farm
• 25 million gallons: Storage at tank farm
• 30 to 40 percent: Total of water used by top 10 (industrial) customers
Areas served by Springdale Water Utilities: Springdale water and sewer; half of Johnson, water and sewer; half of Lowell, water and sewer; Elm Springs, water; Bethel Heights, water; Tontitown, water; unincorporated parts of Washington and Benton counties, water. Water lines stretch almost to Spring Valley community in the east and past Elm Springs in the west.
Source: Springdale Water Utilities
Crews wrap copper cable around new lines so corrosion will attack the copper and not the iron in pipes. The final phase of the ongoing project will start in the spring.
City and state officials said the anti-corrosion work maintains the system and ensures customers receive safe water.
The Water Department wants to prevent line failures such as the one it had near downtown in January 2017, Ward said. Poultry processing plants stopped operations, Springdale schools closed and about nine families experienced cloudy water, which was safe, but not appealing, he said. Crews fixed the problem in less than an hour and prevented a boil order.
Springdale's water system hasn't issued a boil order in about a decade, Ward said. "That's because our water system is healthy," he said.
The state requires a precautionary boil water advisory after pressure drops in distribution systems, said Jeff Stone, director of the engineering section of the Arkansas Department of Health.
Holes in corroded pipes also could cause a system to lose pressure, allowing groundwater to enter the pipe and contaminate the distribution system with bacteria and viruses, Stone said.
"All water systems have leaks," Stone said in an email. "Water system managers monitor their leakage by observing the meter readings of water flowing into and out of the distribution system."
Ward said Springdale Water Utilities can account for 90 percent of where its water goes. The remaining 10 percent is lost to leaks, meter inaccuracies and water used by the Fire Department.
"Unaccounted water rates of 10 percent to 15 percent is considered normal for a water system where management is diligently attempting to find and eliminate leaks," Stone said.
The 2017 Drinking Quality Water Report shows the city system received no violations for sediment in the water, nor for contaminants such as fluoride, nitrates, lead, copper and disinfectants such as chlorine.
"Our mission is to protect public health every day by delivering water of the highest quality. And we take it pretty seriously," Ward said.
City employees test water quality along the 600 miles of pipeline daily, and the utility has developed alternate supply routes for contingencies such as a leak or contamination, he said.
IN SHAPE
Not all soil is corrosive, but some of the pipelines, which were installed in the mid- to late-1970s, cut through pockets that are, Ward said. In one area, the surface dirt was corrosive, but the soil surrounding a pipeline buried 12 feet deep at the same location wasn't, he said.
"We were pleasantly surprised to find a lot of the infrastructure in good shape," said Rick Pulvirenti, chief operating officer and engineering director for Springdale Water.
Ward said only a few corrosive places were replaced because, "We got to it in time."
Springdale Water's $2.2 million anti-corrosion project started last spring and centers on the utility's water tanks on Old Wire Road, Ward said.
The department will finish the project after the Arkansas Department of Transportation moves Arkansas 265 in north Springdale this spring.
The section of pipe needing work is deeply buried along a curve in the road, and the Water Department's work would require one of the highway's two lanes to be closed. Ward said it is safer for workers and drivers for the pipeline construction to happen after the road is moved.
Crews have done some anti-corrosion work along the highway, and Pulvirenti said the lines must be reliable because the road will run on top of them.
Other highly corrosive areas the utility monitors are in the eastern side of Springdale, at the base of the hill leading to the Woodcliff neighborhood and between Friendship and Parsons roads.
"At some point, we might want to dig up the whole thing, but right now, we're making repairs that are effective and will last," Ward said.
CHEMICAL REACTION
Corrosion occurs when the naturally occurring minerals present in the water and soil react with the pipe, said Leslie Pittman, a Springdale School District instructional specialist for science. Electrons on the surface of the metal are removed, and the metal is oxidized.
"It's rusted," she said.
Moisture and salt -- such as chloride -- in the soil often are associated with increased erosion rates, Stone explained.
Water utilities can use installation techniques and material more resistant to corrosion, he said.
The copper cable being attached to the Springdale pipes can lose electrons easier than the pipe can.
This technology is expected to last for 20 years but will be replaced every 10 years, Ward said.
Crews will place test stations along the pipelines, where the conditions and effectiveness of the anti-corrosion efforts can be checked, Pulvirenti said.
Ward said some of the city's water lines haven't been uncovered since they were installed 40 or 50 years ago. The department plans to equip all its repair crews with the necessary equipment so they can add the anti-corrosion device and monitors as they fix leaks.
NW News on 01/21/2019