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

Authors: DIAS, NILDO - Federal Rural University Of The Semi-Arid; FERNANDES, CLEYTON - Federal Rural University Of The Semi-Arid; NETO, OSVALDO - Federal Rural University Of The Semi-Arid; SILVA, CLÁUDIO - Universidade Federal De Uberlândia; Ferreira, Jorge; SÁ, FRANCISCO - Federal Rural University Of The Semi-Arid; COSME, CHRISTIANO - Federal Rural University Of The Semi-Arid; SOUZA, ANA - Federal Rural University Of The Semi-Arid; OLIVEIRA, ANDRE - Federal Rural University Of The Semi-Arid; BATISTA, CARLA - Federal Rural University Of The Semi-Arid

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 6/10/2020
Publication Date: 9/27/2020
Citation: Dias, N.D.S., Fernandes, C.D.S., Neto, O.N.S., Silva, C.R.S., Ferreira, J.F.S., Sá, F.V.S., Cosme, C.R., Souza, A.C.M., Oliveira, A.M., Batista, C.N.0. 2021. Potential agricultural use of reject brine from desalination plants in family farming areas. In: Taleisnik E., Lavado R.S., editors. Saline and Alkaline Soils in Latin America. Cham, Switzerland: Springer. p. 101-118. https://doi.org/10.1007/978-3-030-52592-7_5.
DOI: https://doi.org/10.1007/978-3-030-52592-7_5

Interpretive Summary: After drought, salinity is the second most important hindrance to sustaining agriculture in semi-arid regions. Subterranean waters in many semi-arid regions are often high in salts and not suitable for human consumption or irrigated agriculture. This reality prevents water and food security for many small farmers and communities. Approximately 2.5 million people in the Brazilian Northeast benefit from government-sponsored small water desalinizers, each producing potable water (10,000 L/week) that meets the needs of approximately 30 families. This is a potential solution to the water and food security problem, but the reject brine generated during desalination needs to be properly disposed of to prevent increasing soil salinity and environmental degradation. This chapter presents preliminary results from a study in which reject brine from desalination of naturally saline well waters in the Brazilian Northeast was used in an integrated production system involving farm-raised fish and the use of fish pond water to grow organic salt-tolerant vegetables and forage crops for small ruminants. Our results indicate that the use of desalination reject brine in small-farm agriculture is technically, economically, and socio-environmentally feasible, especially when using integrated and sustainable production systems. The use of desalinized water for human consumption and of the resulting reject brine for agricultural purposes can be a viable solution for the water shortages in semi-arid regions. This integrated system can be feasible for small rural communities and settlements, while helping to generate vegetable and animal protein sources and contributing to environmental conservation of soil and water resources.

Technical 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.