Assessment of Brackish Groundwater Desalination for Municipal and Industrial

Water Supply in Santa Teresa, New Mexico

Project team: Drs. Phil King, Pei Xu, Brian H. Hurd, KC Carroll,Dr. David Johnson, Xuesong Xu, Alfredo Z. Rodriguez

Project partners: Border Industrial Association (BIA)Camino Real Regional Utility Authority (CRRUA)Dr. John W. Hawley, N.M. Bureau of Geol.& Miner. Res.Universidad Autónoma de Chihuahua

Cooperative Agreement Project between NMSU and U.S. BoRStakeholder Meeting, October 24, 2017

• Santa Teresa is a bright spot for economic development• Land Port of Entry to Mexico• Union Pacific intermodal transportation facility• Growing industry base

• Need sustainable water infrastructure

Research Background

• Investigate the hydrogeologic, technical and economic potential for desalinating brackish groundwater in the Santa Teresa-San Jeronimo area

• Conduct a proof-of-concept demonstration with a pilot desalination plant and existing brackish wells

• Develop an organizational and financial plan for moving forward with desalination implementation

Research Objectives

Research Updates• Working with local entities to assess water demand, current supply, and

binational potential• Developed dialog with Universidad Autónoma de Chihuahua’s Department

of Civil Engineering colleagues as project collaborators

Research Updates• Conducted literature review on geophysics- and geochemistry-based

assessment of the Mesilla Basin (Teeple (USGS), 2017)

– Dissolved-solids-concentration data collected during 1922–2007 for 239 wells with water depth from 0-1,750 ft

– The TDS concentrations in the northern part were generally less than 1,000 mg/L– In the southern part, TDS concentrations > 1,000 mg/L were common, but 3,000 –

35,000 mg/L water were found especially with increasing depth

Water Depth: A, 0 feet. B, 250 feet. C, 500 feet. D, 750 feet

Research Updates• Conducted literature review on geophysics- and geochemistry-based

assessment of the Mesilla Basin (Teeple, 2017)

– Dissolved-solids-concentration data collected during 1922–2007 for 239 wells with water depth from 0-1,750 ft

– The TDS concentrations in the northern part were generally less than 1,000 mg/L– In the southern part, TDS concentrations > 1,000 mg/L were common, but 3,000 –

35,000 mg/L water were found especially with increasing depth

Water Depth: E, 1,000 feet. F, 1,250 feet. G, 1,500 feet. H, 1,750 feet

Research Updates

• Of the 44 groundwater samples collected, 82% represented Na-dominated water types, specially Na-Cl-SO4 or Na-HCO3 water types, with the Na-Cl-SO4 water type being the most common (70.5%).

• 18.2% near the Mesilla Valley Fault zone represented Ca-Cl-SO4 or Ca-HCO3 water types

• Conducted literature review on geophysics- and geochemistry-based assessment of the Mesilla Basin (Teeple, 2017)

Research Updates

• Conducted water quality analyses for five groundwater samples from the southern part of the Mesilla Basin– Found elevated As (7-25 ug/L), Na (270-610 mg/L), TDS (900-2600

mg/L), and high spatial variability

• Conducted literature review on geophysics- and geochemistry-based assessment of the Mesilla Basin (Teeple, 2017)

– Combined nitrate plus nitrite (NO3+NO2) < 8.38 mg/L– Sparingly soluble salts may cause scaling, e.g., silica concentration

between 14.5 mg/L and 85.1 mg/L – Below detection limit of selected pesticides

Desalination is needed to produce safe drinking water and sustain the economic development!

Pilot Test/Demo Updates• Acquired pilot-scale test units from NMSU• Testing pilot-scale desalination system using reverse osmosis (RO) and

nanofiltration (NF) membranes

Future Research Tasks• Assessment of demand • Assessment of the brackish water resource for supply

and disposal• Characterization of hydrologic connection with Rio

Grande system• Treatment technology and proof-of-concept field

demonstration• Binational potential

Reference

Teeple, A. P., 2017. Geophysics- and geochemistry-based assessment of the geochemical characteristics and groundwater-flow system of the U.S. part of the Mesilla Basin/Conejos-Médanos aquifer system in Doña Ana County, New Mexico, and El Paso County, Texas, 2010–12. Scientific Investigations Report 2017-5028, prepared in cooperation with the Bureau of Reclamation.

https://pubs.er.usgs.gov/publication/sir20175028