Responsible partner: National Technical University of Athens (NTUA)
Type of feedstock: Seawater desalination brine
Nutrients recovered: Potassium (K) – KCl; Magnesium (Mg) – Mg(OH)2
Process technologies: Chemical Precipitation; Nanofiltration (NF); Multiple Effect Distillation (MED); Selective crystallisation or Flotation
The effluent from the desalination plant (on average 500 L/d brine) will be directed to the first precipitation tank for Mg(OH)2 recovery after NaOH addition. The resulting liquid stream will be fed to the second precipitation tank for CaCO3 removal after Na2CO3 addition. These chemical precipitations, except for Mg recovery for BBFs, will also eliminate scaling problems during Nanofiltration (NF) and Multiple Effect Distillation. NF unit will be used to achieve separation of monovalent from multivalent ions and MED to concentrate the NF permeate. From these process units, high-quality distillate water will also be recovered. The MED concentrate stream containing Na+, K+ and Cl– will be directed to a crystallizer for salts crystallization, i.e. NaCl and KCl and will promote the production of high-quality products. Selective crystallization or flotation will be used for NaCl and KCl separation.