Using “fresh” to determine a source Original Research Article

Water scarcity is a problem facing the arid southwest portion of the United States. Compounding the scarcity issue is the fact that much of the water is also of poor quality. In recent years, the quest for sources of fresh water has intensified as the realization of the potential for long-term water shortages becomes a reality. This paper examines the definition of “fresh” water as a function of the end use of the water, i.e. human consumption, environmental release, or reuse for industrial or municipal applications. It is within this context that a discussion of the term “fresh” is evaluated as a defining criterion for potential sources. The technology to produce good quality water from poor quality sources exists. However, factors other than technology often control the decision making as to whether to treat a water source of poor quality, or continue to look for a source of higher quality. Some of these factors are: public acceptance, environmental impact, regulations, economics, human health risks, regional issues, political issues. The specific case discussed here uses a wastewater source that is highly controversial by its very nature, as it contains radionuclides and other industrial contaminants. The factors leading to this source being considered are as follows: (1) the municipal water production wells are 1500–2000 ft. 457.5–610 m) below the surface making production costly; (2) the groundwater quantity is limited and recharge is extremely slow; and, (3) the groundwater has a high level of naturally occurring silica (80–120 mg/l The case facility, located in western portion of the United States, treats an average of 15,000 gpd (57 m3/d through the use of chemical precipitation, sand filtration, ultrafiltration, ion exchange and reverse osmosis. The secondary waste (reject or concentrate) from this treatment process is further treated with electrodialysis-reversal and mechanical evaporation. The product from this facility is currently discharged, by regulatory permit, to the environment. The product water is being considered for reuse primarily for industrial applications.