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1 Volume 3, Number 4, Fall 1997 Treated Wastewater Recharges Aquifer The El Paso area, including adjacent Ciudad Juarez, Mexico, depends upon the Hueco Bolson aquifer for 65% of its water. Demand is overdrafting the Bolson, whose levels are dropping almost 2 feet annually, and water use projections indicate an upward trend in pumpage will continue. As it stands, withdrawal of groundwater has created a large cone of depression in the water table centered under the El Paso-Ciudad Juarez area, which has a population of more than 1.5 million. About 60% of the advanced tertiary treated wastewater processed by the Fred Hervey Water Reclamation Plant is injected into the bottom of Hueco Bolson Aquifer, a process known as aquifer storage and recovery. The balance of the water is sold to the El Paso Electric Company Newman Power Plant for cooling tower makeup water and to the Painted Dunes Golf Course and the Bowen cattle ranch for irrigation, said Plant Manager Javier Hernandez. (The term "bolson" refers to the sediment-filled basin bounded by the Franklin Mountains on the West, and lower divides and valleys on its remaining boundaries.) Built in 1985, the 10-million gallon/day (mgd) Fred Hervey Water Reclamation Plant treats wastewater from the northeast side of El Paso to Environmental Protection Agency (EPA) drinking water standards, then conveys the water to the three end users. Within the aquifer, reclaimed wastewater mixes with groundwater, shoring up aquifer reserves. About 15 percent of El Paso's water needs are met by reclaimed water. Aside from bolstering groundwater supplies, aquifer injection has also stemmed intrusion of saline water from the Rio Grande alluvium, a shallow aquifer overlying the Hueco2 Bolson. The freshwater zone of the aquifer ranges in depth from 200 feet to 700 feet. Treated wastewater is injected from below to allow mixing with existing groundwater. The Hueco Bolson Recharge Project was designed so that the residence time of the water injected into the aquifer would be at least two years. Owing to the fact that the Fred Hervey plant must provide a relatively constant supply of wastewater to its irrigation and industrial customers, it loses the luxury of operating like a regular wastewater treatment plant, Mike Fontaine, plant operations manager said. Instead of treating wastewater upon demand without much attention to output, the plant must maintain a steady stream of effluent. One 5-million gallon equalization basin acts as a buffer, holding primary treated wastewater collected during periods of high flows in preparation for treatment during times of low flows. Four features distinguish the wastewater treatment and disposal at Fred Hervey from conventional wastewater treatment plants, according to Fontaine: a powdered activated carbon treatment, high-lime treatment, ozone disinfection, and subsequent injection into the aquifer. First, the plant uses a powdered activated carbon treatment in which dissolved pollutants, ammonia, and minute traces of organic contaminants are absorbed. Then the pollutant-laden carbon and bacteria are injected with air, heated, and pressurized, converting them to ash. The carbon not burned into ash is then renewed and reused. The high-lime treatment first raises pH to kill viruses, mitigate hardness, remove phosphorus and precipitate out heavy metals in the form of hydroxides. Carbon dioxide is added later to lower pH. The last unique features are the 10 injections wells, adding between 16 and 44 million gallons of treated wastewater per month into the aquifer. Before actual injection, the polished water is detained 8 hours in 3.3-million gallon clear wells, where a battery of tests ensures that it meets or exceeds EPA standards. Operations Manager Mike Fontaine checks one of 10 injection wells situated west of the Fred Hervey Water Reclamation Plant. Tertiary treated wastewater is injected beneath the Hueco Bolson aquifer at a depth of between 300 and 760 feet. This is one of the deepest polyvinyl chloride pipe wells in the United States.3 Three large ponds which stored primary treated wastewater are being removed from service, due to the risk that storage of untreated wastewater in the unlined ponds has the potential of degrading water in the Hueco Bolson with nitrates as it percolates downward. Fred Hervey was the El Paso mayor who created the El Paso Public Service Board, which oversees the city's water utilities, and encouraged the city to plan for future water needs. Javier Hernandez, (915) 594-5721, is manager of the Fred Hervey Water Reclamation plant. MUD forges partnerships, improves service Talk about turning a problem into an opportunity. When Ron Rodenhaver became general manager of Homestead Municipal Utility District (MUD) in April 1993, he found a crumbling infrastructure, disorganized records, undocumented connections, a large amount of unaccounted for water, accounts more than a year overdue, substandard water quality, a debt problem, and credit so poor that contractors refused to take on repair work. The system was in such disarray that Texas Natural Resource Conservation Commission (TNRCC) had placed a moratorium on new connections. Fast-forward to 1997. Homestead has erased its debt, lowered the rate of levied taxes, constructed two storage tanks totaling half a million gallons capacity with federal funding and is replacing all water lines in its services Unlined holding ponds which stored primary treated wastewater are being removed from service to protect the aquifer from possible nitrate contamination. Storage capacity of one-half millon gallons is represented by new ground and elevated storage tanks. These replaced collections of dilapidated tanks scattered throughout Homestead's service area4 area while installing fire hydrants. Old wells yielding substandard water and storage tanks have been deeded to El Paso County for future parks and other construction. Governing magazine named Rodenhaver one of its 10 Public Officials of the Year in 1996 for his achievement in turning around the MUD, for coordinating improvements with all levels of governmental entities, and for taking over a "debt-ridden, environmentally unsound, bureaucratically wasteful organization and delivering to its customers the first decent water and fair prices many of them had ever seen." Located in an unincorporated community northeast of El Paso between El Paso city limits and the slope of the Hueco Mountains, the


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