Brines from industrial water recycling: new ways to resource recovery

Abstract

Stricter environmental regulation policies and freshwater as an increasingly valuable resource are leading to global growth of zero liquid discharge (ZLD) processes in recent years. During this development, in addition to water, the recovery of recyclable materials, e.g. salts, from industrial wastewater and brines is considered more frequently. Within the framework of the HighCon research project, the subject of this study, a new ZLD process with the goal of pure single-salt recovery from industrial wastewater has been developed and investigated in a demonstrational setup at an industrial site. With regard to pure salts recovery, separating organic components is of great importance during the treatment of the concentrate arising from used water recycling. The removal of COD and of ions responsible for scaling worked very well using nanofiltration. The nanofiltration permeate containing the monovalent ions was pre-concentrated using electrodialysis and membrane distillation before selective crystallization for single-salt recovery was performed. An example economic case study for the newly developed ZLD process – based on demonstration results and considering optimization measures for a full-scale design – indicates that the costs are equal to those of a conventional ZLD process, which, however, does not provide inter alia the aforementioned benefit of single-salt recovery.

Water management for Power-to-X offshore platforms: an underestimated item

“…RO brine treatment would also provide further recirculation of hydrogen, considering around 70% of the feed water is returned to the sea. ZLD would be a potential strategy for this, however, its implementation on brine treatment and management is still expected to see a progressive growth 17 , 40 . Previous studies on brine management by ZLD have reported energy consumptions of conventional brine concentrators of up to 39 kWh m −3 41 , whereas conventional crystallizers may reach up to 70 kWh m −3 38 .…”

“…Zero liquid discharge (ZLD) has previously been considered for treating brine 17 , 38 as well as wastewater 39 . Conventional ZLD approaches consist of a series of thermal processes, often in combination with membrane technologies 40 . Although ZLD is becoming very popular in industrial wastewater treatment in several countries, the energy consumption and the implementation cost remain very high.…”

Application of Seeded Membrane Distillation Crystallization for Zero Liquid Discharge

“…The European Union's chemical strategy for sustainability, which aims to create a toxic-free environment, emphasizes the need for further purification of municipal and industrial wastewater. Moreover, rising wastewater costs [7,8] highlight the necessity for enhanced and integrated processes.…”

Electrodialysis with Bipolar Membranes for the Generation of NaOH and HCl Solutions from Brines: An Inter-Laboratory Evaluation of Thin and Ultrathin Non-Woven Cloth-Based Ion-Exchange Membranes

“…However, a ZLD strategy also includes post-concentration processes based on energy-intensive practices to achieve zero liquid waste [5]. Nevertheless, only in a few previous works have ZLD and MLD strategies focused on valorising these concentrated streams to recover or produce valuable compounds (e.g., recover single [6] or mixed salts [7]). Consequently, the need to develop the on-site chemical production of commodities, such as strong acids and bases, has identified the use of electrodialysis with bipolar membranes (EDBM) as a technological driver to achieve this objective through the valorisation of waste brines.…”