A review of strategies for RO brine minimization in inland desalination plants

This paper aims to review the differences between seawater, brackish and coal seam gas water desalination and the challenges faced; critically review the existing technologies for minimizing the brine volume and zero liquid discharge in inland desalination; highlight the scaling potential in these technologies; provide insights into strategies integrating an intermediate ‘high pH precipitation treatment’ with another concentration system for Reverse osmosis brine minimization for groundwater supplies; and analyze more complex ZLD and volume reduction systems like the high efficiency RO and the SAL-PROCTM

Javier Rioyo; Vasantha Aravinthan; Jochen Bundschuh; Mark Lynch

2017

Scholarcy highlights

  • As freshwater supplies diminish, desalination of brackish groundwater resources is becoming an increasingly viable option for inland communities in countries that have limited access to fresh surface water supplies or desalinated seawater to meet increasing demand
  • This paper aims to review the differences between seawater, brackish and coal seam gas water desalination and the challenges faced; critically review the existing technologies for minimizing the brine volume and zero liquid discharge in inland desalination; highlight the scaling potential in these technologies; provide insights into strategies integrating an intermediate ‘high pH precipitation treatment’ with another concentration system for Reverse osmosis brine minimization for groundwater supplies; and analyze more complex ZLD and volume reduction systems like the high efficiency RO and the SAL-PROCTM
  • The feasibility of membrane electrolysis technology for NaOH production using brine generated in seawater or CSG water desalination facilities had been reported in previous studies
  • Risk of groundwater contamination Discouraged or banned for CSG water management in Queensland Risk of groundwater contamination Influenced by weather conditions Risk of scaling and fouling Further research required for process optimization Leading technology Rw limited by the risk of scaling and the practical limits to provide the osmotic pressure Rw in evaporators limited by scaling Further research required to develop new systems recovering residual heat or steam Cost-effective only for treating waters with total dissolved solids level below 10,000 mg/L Further research required to avoid scaling and to improve selectivity and permeability of membranes High concentration capacity Rw limited by the risk of scaling Need to develop more robust membranes and a suitable draw solution Promising alternative Further research required to avoid scaling
  • Antiscalants are often dosed during RO pretreatment to prevent membrane scaling
  • The Rw increased from 80% to 90% for the non-ozonated brine and from 80% to 94% for the ozonated brine
  • No matter which concentration technology is selected for RO brine minimization, it becomes necessary to cope with the scaling potential problem

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