Potential agricultural use of reject brine from desalination plants in family farming areas

Abstract

After drought, salinity is the second most important hindrance to sustain agriculture in the semiarid. Subterranean waters extracted from wells are often high in salts and, during dry years, this dependency on saline ground water precludes water and food security for small farmers and their families. Water desalination offers a potential solution to this problem, but the process results in a reject brine that needs to be properly disposed of to prevent increasing soil salinity and environmental degradation. This chapter considers desalination of naturally saline well waters as a potential solution to water and food security when used in conjunction with an integrated production system involving reject brine for farm-raised fish and the use of fish pond water to grow organic salt-tolerant vegetables and forage crops for small ruminants. We present results on the recovery of desalination systems in different small communities in the Brazilian northeast and chemical analyses of the saline water input, of the desalinized water, of the resulting reject brine, and of soils that received the desalinized water. Our results indicate that the use of desalination reject brine in family agricultural production is technically, economically, and socio-environmentally feasible, especially when using integrated and sustainable production systems.