Reuse of RO Desalination Plant Reject Brine

In this work we try to study the feasibility of salt production from a reject brine coming from a desalination plant in Skhira in the south of Tunisia, This plant treats 22,008 m(3)/day of raw water to produce 9984 m(3) of fresh water and 12,024 m(3) of rejected water and has the advantages of being environmentally friendly and producing commercial products in crystalline, slurry, and liquid forms. The process involves an application of the solubility diagrams in order to valorize the reject brines. These solutions are considered as strongly concentrated brines and containing several elements such as: Na(+), K(+), Mg(2+), Ca(2+), Cl(-), and SO(4) (2-). This observation leads us to consider the complete hexary system Na(+), Mg(2+), K(+), Ca(2+)/Cl(-), SO(4) (2-)//H(2)O which includes four quinary systems. A number of physico-chemical analyses were employed (Potentiometry, complexometry, gravimetry, XRD, and SEM). At the end of an isothermal and isobaric evaporation of the reject brine, we could recover various salts (NaCl, KCl, CaSO(4)center dot 2H(2)O, MgSO(4)center dot 7H(2)OaEuro broken vertical bar) very useful for industry and agriculture.