At one of Europe’s largest silica producers, Industrias Químicas del Ebro (IQE), the ZERO BRINE project has demonstrated circular economy through the recovery of resources from industrial waste brine.
The production of silica is highly water-intensive, resulting in brine discharge containing a high concentration of sodium sulphate. Through pre-treatment of the effluent and the application of two membrane processes – pressure-driven filtration with regenerated membranes and electrodialysis with bipolar membranes (EDBP) – ZERO BRINE is recovering valuable resources and supporting resource efficiency.
Filtration with regenerated membranes provides pure water that can be reused in the on-site production of silica, reducing the water abstracted, as well as a high concentrated brine from which sodium sulphate can be recovered through crystallisation technologies. The recovery of sodium sulphate allows for additional valorisation in the powdered detergent or glass industry.
EDBP provides water recovery for on-site reuse and two reagents, sodium hydroxide and sulphuric acid, that can also be internally valorised in the production process.
Full integration of the ZERO BRINE technologies at IQE would reduce water consumption by more than 1 million m3 annually, while the elimination of brine disposal through its conversion to water and salt would see a 60% reduction of sodium sulphate discharged into the Ebro River, providing environmental benefits.
The feasibility of waste heat was also researched at IQE, finding that a reduction of 72% on energy consumption could be achieved with a payback period of 5 years.