Desalination of Impaired Water Using Geothermal Energy

Craig Turchi, Sertac Akar, Tzahi Cath, Johan Vanneste, Emily Gustafson, John Akerley

Research output: Contribution to conferencePaperpeer-review

Abstract

Membrane distillation (MD) and nanofiltration (NF) are explored as a means to provide high quality water for on-site use at the Tuscarora geothermal power plant in northern Nevada. The plant uses a wet cooling tower, but decreasing flow from the wells providing makeup water necessitates exploration for alternative water or alternative cooling sources. Scenarios are explored to extend cooling water by (1) extracting fresh water from the geothermal brine, (2) upgrading the makeup-water quality to allow for increased cycles of concentration in the cooling tower, or (3) recovering water from the cooling tower blowdown. The preliminary cost analysis indicates that applying NF to extract water from the injection brine is the most attractive option of the scenarios examined. This approach may be useful for other plants as well. The estimated cost for the NF treatment of the injection brine ranges from $0.63/m3 to $0.45/m3 and provides a reduction in the current makeup well flows of 35% to 71%. Savings from the reduction in makeup well pumping and chemical treatment do not fully offset the estimated cost of the proposed treatment systems; the site will have to weigh the cost of these water treatment options versus alternatives in light of the diminishing flows from the existing cooling-water wells. Testing is planned to quantify the performance of the proposed NF and MD technologies and help refine the estimated system costs.

Original languageAmerican English
Pages258-276
Number of pages19
StatePublished - 2017
EventGeothermal Resources Council 41st Annual Meeting - Geothermal Energy: Power To Do More, GRC 2017 - Salt Lake City, United States
Duration: 1 Oct 20174 Oct 2017

Conference

ConferenceGeothermal Resources Council 41st Annual Meeting - Geothermal Energy: Power To Do More, GRC 2017
Country/TerritoryUnited States
CitySalt Lake City
Period1/10/174/10/17

NREL Publication Number

  • NREL/CP-5500-68502

Keywords

  • Desalination
  • Direct use
  • Low-temperature geothermal
  • Membrane distillation
  • Nanofiltration

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