Membrane and electrodialysis based seawater desalination with salt, boron and gypsum recovery

A system, comprising:

• a nanofiltration (NF) unit configured to separate seawater into a first permeate and a first non-permeate, wherein the first non-permeate comprises first minerals and the first permeate comprises second minerals;
• a first stage mineral recovery unit disposed downstream from and fluidly coupled to the NF unit, wherein the first stage mineral recovery unit is configured to receive the first non-permeate from the NF unit and to capture at least a portion of the first minerals;
• a second stage mineral recovery unit disposed downstream from and fluidly coupled to the NF unit, wherein the second stage mineral recovery unit is configured to receive at least a portion of the first permeate and to capture the second minerals, the second stage mineral recovery unit comprises a multi-stage electrodialysis (ED) system comprising a first ED unit and a second ED unit, the first ED unit is configured to separate the first permeate into a diluate and a concentrate, the concentrate comprises the second minerals, wherein at least one of the first ED unit, the second ED unit, or both is a non-selective ED unit;
• a first reverse osmosis (RO) system fluidly coupled to the second stage mineral recovery unit, wherein the first RO system is configured to receive the diluate from the first ED unit and to generate a first brine and a second permeate;
• and
• a first flow path between the first RO system and the second ED unit, wherein the first flow path is configured to supply the first brine to the-second ED unit.

A system, comprising:

• a first stage mineral recovery unit disposed downstream from and fluidly coupled to a nanofiltration (NF) unit, wherein the first stage mineral recovery unit is configured to receive a first non-permeate having first minerals from the NF unit and to capture at least a portion of the first minerals;
• a first flow path fluidly coupling the first stage mineral recovery unit and a dolime source, wherein the first flow path is configured to supply the first stage mineral recovery unit with dolime such that at least one of the first minerals recovered in the first stage mineral recovery unit is magnesium hydroxide;
• a second stage mineral recovery unit disposed downstream from the NF unit and the first stage mineral recovery unit, wherein the second stage mineral recovery unit is configured to capture second minerals from a first permeate generated by the NF unit, and the second stage mineral recovery unit comprises a multi-stage electrodialysis (ED) system, wherein the multi-stage ED system comprises at least one non-selective ED unit;
• and a first reverse osmosis (RO) system disposed downstream from and fluidly coupled to the second stage mineral recovery unit, wherein the first RO system is configured to receive a diluate generated by the multi-stage ED system and to generate a first brine and a second permeate.