Integrated Wind-Water Treatment System
Municipalities in the Texas High Plains face ongoing challenges as they plan for
long-term water supplies. Cities are dependent upon the relatively shallow and
typically fresh Ogallala Aquifer for most of their potable water. The recent extended
drought has greatly diminished surface water supplies in area lakes which normally
contribute to the water supplies of 19 cities, increasing their current groundwater
use and putting more pressure on the rapidly diminishing aquifer. For much of
the Texas Panhandle, Ogallala groundwater will only be available for 20 to 40
more years for both traditional irrigated agriculture and municipalities unless this
problem is addressed.
A recent survey conducted by Texas Tech University (TTU) researchers reported
that some regional public groundwater supplies are out of compliance with federal
standards, with high levels of fluoride, arsenic, total dissolved solids (TDS),
and other contaminants. Removing these contaminants demands more involved
treatment processes beyond disinfection or blending with less impacted well water–
additional treatment that will require new infrastructure and increased operation
and maintenance costs, including electricity.
In 2005, researchers from the TTU National Wind Institute and Water Resources
Center began exploring the potential for connecting locally owned renewable
wind energy systems with the electrical needs for pumping and treating locally
available brackish groundwater. Reverse osmosis (RO) offers a solution but requires
a substantial electricity source. The intent of the TTU project is to utilize renewable
energy to reduce the community’s grid electricity needs with the idea that shifting a
significant portion of the electrical needs associated with drinking water delivery in
that same time window will mean storing lower cost energy in the produced water.
Through community outreach, the research team was approached by Mayor
Mike Carter and other officials of Seminole, Texas, a community of 6,768, with a
declining Ogallala well field impacted by arsenic and fluoride. City officials were
interested in drilling deeper wells to tap the water in the Santa Rosa aquifer. The
TTU research team agreed to collaborate with the city to develop and deploy a
field-scale demonstration project and funding was obtained from the Texas Water
Development Board, Texas Department of Agriculture, State Energy Conservation
Offi ce, Llano Estacado Underground Water Conservation District, and the
Department of Energy.
The demonstration project has been constructed and continuous operation of the
system began in April 2013 for a target period of 12 months. The typical produced
brackish groundwater has 8200 ppm of TDS, while the treated water has 440 ppm.
Under typical windy conditions, the 50-kW capacity wind turbine easily provides
the approximately 20 kW needed to power the well, RO system, and other related
processes. The data collected will be examined and applied to future models with
the potential to impact water availability for arid and semi-arid environments
across the world.
Ken Rainwater, professor, Department of Civil Engineering,
(806) 834-7775 or ken.rainwater@ttu.edu
Site preparation and construction equipment during the
process of building the integrated wind-water treatment
system demonstration project in Seminole.
The skid-mounted desalination system includes both
first stage (lower two white pipes) and second stage RO
membranes to remove over 94 percent of the TDS from
the treated water.
The 50-kW wind turbine stands just under 130-ft tall
between the RO building and the 1800-ft deep brackish
groundwater well at the Seminole site.