Water resource management is facing an increasing interplay between water supply and water quality issues. Desalination of seawater and brackish groundwater must manage brine streams. Agricultural water users generate runoff with high salinity and high concentration of pesticides. Fortunately for society, water quality problems have captured the attention of entrepreneurs and inventors.
EFD Corporation made an interesting presentation in June at the Monterey Bay International Trade Association, an event linking marine-tech entrepreneurs with potential investors in desalination projects on the Monterey Peninsula. The proposed desalination projects in Monterey, for example, would take an acre-foot of seawater to produce a half acre-foot of drinking water and a half acre-foot of a brine stream. The brine stream contains 48 tons of salt per acre-foot.
The firm’s patented technology can transform the brine stream from seawater desalination into distilled water and dry salt. It is based on combining two well-understood and reliable technologies: vapor compression and spray drying. Vapor compression has been used in a variety of applications ranging from desalination, heat pumps and refrigeration. Spray drying is used in the sugar and pharmaceutical industries to separate liquids from solids. The patent was granted for the purpose of using these technologies to separate seawater into salt and distilled water.
EFD calculates that the dry salt extracted from the brine stream would have a market value of $1,800 per acre-foot. By transforming “salt management” from a liability to an income stream, EFD proposes to transform the economics of water management. Its technology also captures latent energy of vaporization in steam, reusing 90% to 95% of heat. This will further reduce the economic cost of desalination.
EFD technology can also be used in mobile machines suitable for addressing agricultural water quality problems. Most drainage districts in the Central Valley, for example, are under regulatory orders to stop the runoff of brackish water into rivers. The high salinity and contamination of agricultural runoff in the Imperial and Coachella Valleys contribute to water quality problems in the Salton Sea. A technology that can generate a new income stream can improve the economics of addressing water quality management problems throughout the water sector.
EFD’s next step is to finish and test a scaled-up demonstration. The company is in discussions with Cal-Am to use Cal-Am’s small desalination facility in Sand City for a pilot project.
In a JOW interview, EFD President Robbi Magnuson said that her firm “is driven by solving the brine stream problem of desalination to protect the marine environment as much as becoming a financially-successful water technology firm.” When EFD technology becomes available in 2016, it may become a “disruptive” technology for the water industry. For more information, visit www.efdcorp.com.
Written by Rodney T. Smith, Ph.D.