Desalination of brackish water is an attractive option for fresh-water deprived areas. However, concentrate disposal could impede further consideration of desalination because of legal, technical, and cost challenges, especially for smaller communities with a limited budget. Evaporation ponds offer a viable low cost alternative for facilities with a production of 1 million gallons a day or less. An even better alternative is to engineer ponds such that they generate their own sealing materials, possibly eliminating the need for a synthetic liner or at least adding another layer of protection in sensitive areas.

This study focuses on the geochemical aspects of mineral precipitation in a pond combined with a field assessment of actual Texas evaporation ponds. Pond chemistry and chemical pathways depend on the nature of the concentrate, itself dependent on the source water chemical composition. We present a range of likely pond chemical composition and propose additives to help in precipitating useful sealing materials such as calcite, gypsum, and especially sepiolite, a non-swelling clay that has been showed multiple times both in natural analogs and in the laboratory to precipitate directly from Mg-rich, slightly alkaline waters. We conclude with suggestions on pond design.