In common parlance, reverse osmosis (RO) is often described as removing salt from water. In practice however, these processes squeeze water from a salt solution resulting in concentrate to be disposed or treated further in more expensive processes which pose significant challenges to the viability of a project. Disposal options may be cost-prohibitive or unavailable altogether, while conventional options for Minimal Liquid Discharge (MLD) and Zero Liquid Discharge (ZLD) bear significant capital cost and energy consumption. The current 1200PSI (83bar) environment for membrane desalination and concentration was established at the turn of the millennium. In this time, seawater reverse osmosis (SWRO) recoveries of 40%-50% have been the norm with maximum brine salinities of 80 – 90k ppm in concentration and reuse applications. However, demand for higher RO pressures to address feed salinity and concentration requirements conflict with efforts to reduce capital cost and energy consumption, requiring advanced membrane solutions for increased recovery and concentration. Today’s generation of Ultra High Pressure (UHP) systems rated for 1740PSI (120bar) represent the convergence of established practices, innovative design, and new products. Taking a page from longstanding high recovery brackish RO practices, multistage systems optimize feed and brine velocity to limit fouling and scaling, while recent developments in proven UHP turbocharger technology and application have demonstrated that designers can distribute brine energy to each stage as needed to optimize net driving pressure and velocity for balanced, stable high recovery operation. The successful implementation of a two-stage SWRO plant with dual turbochargers in Mexico demonstrated that 60% recovery can be reliably achieved with low energy consumption and fouling using conventional membranes. In addition, an upcoming brine concentration/ZLD project in Saudi Arabia will demonstrate that UHP can be reliably and economically achieved for brine mining of valuable minerals. These proven practices are entirely applicable to UHP, providing the framework for implementation of today’s UHP membranes and turbochargers as well as supporting equipment such as pressure vessels and couplings.
This presentation is available to AMTA Members only.
Speaker
- Michael Gisclair
Company
- Fluid Equipment Development Company (FEDCO)
Event
- AMTA/AWWA Membrane Technology Conference, West Palm Beach, FL
Session
- AMTA/AWWA Membrane Technology Conference
Date
- 07/20/21
Media
Keywords
- Reverse Osmosis, SWRO, Ultra High Pressure
Reference
- 9710-DP2735