A mini-review on the use of high-pressure reverse osmosis (HPRO) in desalination and water treatment

Desalination of brackish and seawater is a critical solution to global water scarcity, yet it produces brine volumes nearly double that of freshwater output, creating serious environmental concerns due to elevated salt and chemical concentrations. High pressure reverse osmosis (HPRO) represents a novel and promising strategy to overcome these limitations by achieving higher water recovery and minimizing brine discharge. While first explored for landfill leachate treatment in the 1990s, recent developments have shifted toward applying HPRO to seawater brine, marking an important technological transition. This review provides the first comprehensive synthesis of recent progress in HPRO applications for desalination brine, landfill leachates, and industrial effluents. It integrates experimental and modeling studies to evaluate performance, energy efficiency, and process optimization, while offering a critical assessment of operational barriers such as membrane compaction, concentration polarization, scaling, and biofouling. Novel mitigation strategies such as nanofiltration pretreatment for divalent ion removal are highlighted as enablers of reliable HPRO operation. Importantly, this review identifies underexplored research directions that can advance HPRO from promising concept to mature technology. These include long-term pilot-scale testing with real seawater brine, comparative life cycle assessments, mechanistic studies of fouling, and the engineering of robust HPRO modules for sustained high pressure operation. By positioning HPRO as a next-generation approach that not only reduces brine volumes but also enables brine squeezing, resource recovery, and sustainable wastewater treatment, this review underscores its novelty and transformative potential in addressing the environmental footprint of desalination and related industries.