New Mexico, USA
November 4, 2014
Manoj Shukla, New Mexico State University professor of soil physics, is trying to research the use of highly saline water. Here, shown at the Brackish Groundwater National Desalination Research Facility in Alamogordo, with the plant’s facility manager, Randy Shaw. (Courtesy Photo)
As drought continues to plague New Mexico, alternatives such as using wastewater have been tested and used for agriculture and urban irrigation. In the quest to conserve potable water and still maintain agricultural practices, Manoj Shukla, NMSU professor of soil physics, is trying to research the use of highly saline water.
Since 2013, he has been experimenting with water from the Brackish Groundwater National Desalination Research Facility in Alamogordo, researching the uses and impact of desalination in the environment, particularly if used in agriculture.
Shukla began a germination experiment in 2013 with six plant species to determine their reaction to saline water. He, along with his graduate assistant and other NMSU researchers, did a greenhouse screening study of barley and triticale, which are plant foods; lepidium alyssoides and Switchgrass, considered biomass plants; and Atriplex and NiPa Grass, which are fodder plants.
The plants were germinated in petri dishes and given four saline treatments, including tap water from Skeen Hall and water from the desalination facility in Alamogordo.
“There are two reasons we chose these plants. Number one is that we knew that some of these plants can be grown under highly saline water. Number two is that the Bureau of Reclamation Cooperative Agreement, which is funding this project, and the NMSU Institute for Energy wanted us to use these plants,” Shukla said.
He added that water supplies in arid regions such as New Mexico are valuable even when high in salt. Through proper understanding of the transport behavior of concentrate, proper plant selection and proper management, the concentrate can be used to irrigate halophytes, plants that grow in salty environments, year-round.
The other part of his experiment dealt with soil and its salinity retention. For this experiment several plants were planted in clay soil, brought from the brackish water plant, and silica sand.
His investigation states that there is more research to be done to study the behavior on concentrate in soil to determine “leaching and deposition depths, identify salt tolerant crops and develop a plan for managing concentrate throughout the year with or without crop.”
Both experiments proved that to some extent and with certain variations, the plants were able to grow in saline water, and he will continue testing soil types and their properties to better assess a concentrate disposal strategy.
“We should really continue to do more research looking at the plant survival as well as the behavior of the concentrate and how deep it can move in the soil before we can use it in the fields,” he said.
One of the challenges Shukla and his team are facing is how to dispose of high salinity water without damaging the environment and affecting groundwater reservoirs.
Given that the total volume of water in aquifers in New Mexico is about 20 billion acre-feet, and 75 percent of the groundwater is too saline to use, Shukla is trying to find alternative use for the concentrate.
“A solution could be to use the water as drinking water, in different levels, or it could be used for agriculture and vegetation in the area if mixed with treated wastewater, which it has already been used for in certain agricultural areas,” he added. “Most people don’t know, but this concentrate can even be harvested for biofuel.”
Shukla is concerned that the inappropriate disposal of saline water can result in environmental damage since it cannot be placed in the soil because rain might force the concentrate to the groundwater aquifers.
“We have two desalination plants, one in Alamogordo and one in El Paso, and one of the major reasons we do not have many desalination plants in the area is because of the problems associated with the safe disposal of concentrate,” he said. “So, it is easy to pump the ground water, run it and separate the clean water from the concentrate, but we need to find a way to safely dispose of the concentrate.”
Funding for Shukla’s research has been extended and he wants to continue his research and collaboration with the brackish water plants in the area.
“The future uses can be great for New Mexico,” he said. “There are uses for concentrate and we want to make sure we find solutions that can benefit the people in this area.”
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