The Survival and Growth of Spirulina spp. in the Saline Groundwaters of New Mexico

New Mexico has some 15 billion acre-feet of saline groundwater. Much of this water has a salinity greater than 3,000 ppm Total Dissolved Solids (TDS) and thus cannot be used for potable water nor traditional agricultural activities.

The main objective of this project was to determine the technical feasibility of growing Spirulina in New Mexico using these saline groundwaters. Spirulina was chosen because it grows naturally in highly alkaline lakes in hot climates and is more readily harvested than other algae. Spirulina has many potential uses, ranging from a potential feedstock for ethanol fermentation and anaerobic digestion to a source of specialty chemicals ( -carotene, phycocyanins, tocopheral) to a highly nutritious feed ingredient for livestock and for aquatic organisms. Its highest economic value use is as a human health food.

For this project, a state-of-the-art algae cultivation facility was designed and built at the Roswell Test Facility (RTF). The cultivation facility consists of two, 50 square meter concrete raceways enclosed in greenhouses. Additionally, the facility houses a computerized measurement and control system, as well as a water treatment/recycling system. We have demonstrated that Spirulina can be successfully grown at this pilot scale plant using saline groundwaters.

Laboratory studies support empirical observations made at the pilot plant that several species of Spirulina will grow in full RTF saline water (14,000 ppm TDS), half RTF water (7,000 ppm TDS), New Mexico State University (NMSU) geothermal water (2,000 ppm TDS) and NMSU tap water (500 ppm TDS). Further, these species are capable of excellent growth at temperatures as high as 42øC. Growth appears to slow at 20øC and below.

In addition, experience has been gained in working with this saline water on a practical level. It is known how to minimize turbidity and precipitation problems that arise from the interaction of the saline water with added algal fertilizer and analytical procedures have been modified to work with the saline water and high standing densities of the Spirulina.

The technical feasibility of Spirulina cultivation in New Mexico using saline groundwaters has been demonstrated. Market research should be performed to determine the size and location of potential markets and the price structure. If market research data is favorable, a small commercial size Spirulina culture operation should be established and operated for at least a year to determine actual operating and capital costs.