Maximize the operating profit of a SWRO-PRO integrated process for optimal water production and energy recovery


Simple model to predict the performance of PRO modules with dilution.

Optimize the SWRO-PRO system to maximize the operating profit.

SWRO-PRO can increase the recovery and the operating profit simultaneously.

SWRO-PRO can reduce the specific energy consumption by up to 35%.

SWRO-PRO can increase the operating profit by up to 100%.


Pressure retarded osmosis (PRO) is a promising technology to reduce the specific energy consumption and the operating expenditure of a seawater reverse osmosis (SWRO) plant. In this study, a simple analytical PRO model is developed to predict the PRO performance as the dilution of draw solutions occurs. The model can predict the PRO performance with a high accuracy without carrying out complicated integrations and experiments. The operating profit of SWRO-PRO is also studied by calculating the profit generated for every m3 of seawater entering the process because maximizing the operating profit is the uttermost objective of the SWRO-PRO process. Based on the PRO analytical model, the operating profit and the dynamics of the SWRO-PRO process, a strategy has been proposed to maximize the operating profit of the SWRO-PRO process while maintaining the highest power density of the PRO membranes. This study proves that integration of SWRO with PRO can (1) push the SWRO to a higher recovery and maintain its high profitability, (2) effectively reduce the specific energy consumption of desalination by up to 35% and (3) increase the operating profit up to 100%.

Graphical abstract

Based on in-house developed hollow membranes with a peak power density of 26 ± 1 W/m2 at 20 bar using 1 M NaCl as the draw solution and DI water as the feed solution.


  • Reverse osmosis;
  • Pressure retarded osmosis;
  • Osmotic energy;
  • Energy recovery;
  • Operating profit;
  • Process optimization

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