By Cassie McClure
Published in the Las Cruces Sun-News 12/27/20.
In December, Las Cruces Utilities (LCU) added a NO-DES truck and trailer to its fleet. Using patented technology, the new equipment will avoid hydrant flushing, cut down on service interruptions to customers, and be a sustainable way to solve water quality issues while conserving water.
“LCU looks for ways to be a better steward of our water supply in southern New Mexico,” Adrienne L. Widmer, P.E., interim assistant utilities director, said. “Effective water management that improves water reliability is a key component to carry out the City’s Drought and Water Emergency Response Plan and is a critical aspect of the City’s 40-Year Water Development Plan.”
Thanks to the U.S. Department of the Interior’s Bureau of Reclamation WaterSMART (Sustain and Manage America's Resources for Tomorrow) project, the City of Las Cruces (City) was awarded a grant for 50 percent of the cost of the truck, which totaled $524,907. The NO-DES truck – a Neutral Output Discharge Elimination System – is an investment that made sense, explained Widmer.
“The NO-DES was a high priority for LCU and City Council to solving water distribution system issues without water waste. In addition to the water lost, there is a cost to the City for this process,” Widmer said. “Water flushed from the hydrants has been pumped, treated, and distributed at a cost to the utility. This cost is being lost by the City and its residents when the hydrants were flushed.”
The NO-DES truck and 20-foot trailer produce zero water waste. When attached to two hydrants, the NO-DES pump circulates water at desired flows in the opposite direction of the natural flow of the line being flushed. This stirs up sediment and scours the inside of the main, which is more effective than conventional flushing.
“Because the water being flushed is maintained between the two hydrants, there is no possibility of contamination in other parts of the water system, as with conventional flushing, and customers will not experience the temporary increase of red water entering their homes,” Widmer said.
Las Cruces water customers sometimes experience “red water.” Red water is due to naturally occurring iron and manganese found in the water supply. Metals like iron and manganese tend to oxidize and settle in water lines, especially when the water demand is low, and water is moving slowly. Las Cruces water is chlorinated to kill bacteria, but chlorine can oxidize the iron and manganese and cause them to precipitate, making the water reddish-brown.
Widmer further explains, “LCU had used the innovative NO-DES technology before with fabulous results. We anticipate cleaning all City water distribution lines within the next two years and will continue to clean the lines, thus lowering the need for conventional fire hydrant flushing.”
Anyone who notices discolored water coming from their pipes is encouraged to flush their exterior or interior cold-water faucets for 5 minutes. If discoloration continues, please reach out to LCU Emergency Dispatch 24-hours a day at (575) 526-0500.
LCU can be reached at 575-528-3500 from 8 a.m. - 5 p.m. Monday through Friday. LCU provides services to approximately 100,000 Las Cruces residents and businesses.
PHOTO 1: The NO-DES truck and trailer during training in San Andres Estates, which has a 50-year-old water system.