The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project is to significantly increase the efficiency and reduce operating costs for water produced by membrane-based desalination. Water scarcity is an increasingly important global-scale issue that has significant negative impacts on health, security and economies. Recent forecasts show a dramatic increase in the number of countries that will soon be affected by water scarcity given that global water consumption is expected to significantly increase due to population growth. Membrane-based water desalination, which at large scale requires a huge capital investment, is recognized as a primary technology that can significantly improve supply to meaningfully offset scarcity and its impacts. A critical factor in desalination plant operations is energy consumption, which increases due to membrane fouling, thus making fouling one of the most significant factors controlling the efficiency of these plants. The proposed in-situ, real-time sensing system can be the enabling technology to allow implementation of advanced plant control algorithms based upon accurate detection of fouling at its earliest stages. Such active detection capability will enable the most effective implementation of fouling mitigation strategies that can be optimized to save energy and reduce cost.This SBIR Phase I project proposes to develop a novel time-reversal waveguide sensor for detection of early-stage (ES) fouling in reverse osmosis (RO) membrane desalination, which is the dominant technology for desalinating brackish water and seawater. Fouling in RO systems has inorganic (scaling) and organic (biofouling) components and can be a highly variable process that depends on operational parameters as well as environmental conditions. Efficient implementation of real-time control of RO desalination for fouling mitigation requires real-time sensing. The overall objective of the proposed work is to develop sophisticated ultrasonic sensor technology that can reliably detect scaling and biofouling in the challenging multi-layer, spiral-wound (SW) geometry of commercial-scale RO systems. The proposed work will make use of time-reversal mirrors to produce a simple signal from a multi-mode waveguide independent of the geometry of the waveguide configuration, thus overcoming the exceedingly complex and difficult to interpret signals associated with the use of a standalone waveguide. The goals of the project are to demonstrate the capability to detect both early-stage inorganic and organic fouling under realistic operating conditions, the reliability and the robustness of the technology, and the ability to adapt the technology to the larger size modules that are increasingly important for commercial operation.
