High Recovery Desalination for Expeditionary Water Production

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Biotechnology; Advanced Materials OBJECTIVE: Develop innovative water treatment technologies that achieve high-recovery desalination of seawater and brackish water, maximizing potable water production while minimizing waste generation, beyond the limitations of conventional reverse osmosis. DESCRIPTION: The Army requires advanced water treatment solutions to support sustained operations in distributed and austere environments. Current fielded systems rely on reverse osmosis for desalination, but this technology has inherent limitations when operating at high recovery rates, including membrane fouling, increased energy demands, and declining performance over time. To enhance unit self-sufficiency and reduce reliance on external water resupply, novel desalination approaches that enable efficient, high-recovery water treatment are needed. This topic seeks to advance research into desalination technologies capable of treating water sources with total dissolved solids (TDS) ranging from below 500 mg/L to 60,000 mg/L. A primary challenge is achieving and sustaining high recovery rates, specifically targeting: >85% (Objective) and >75% (Threshold) recovery rate for water treatment. Operation in expeditionary environments, requiring: Rapid startup and shutdown. Capability to function while in motion. Ability to treat water from both external sources and onboard vehicle storage tanks. Enhanced efficiency beyond reverse osmosis, overcoming limitations such as: Membrane fouling and scaling. Degraded performance at higher TDS levels (>45,000 mg/L). Increased energy consumption and operational costs. Compact, robust, and scalable design, suitable for mobile and austere conditions. To achieve these goals, the Army is looking for fundamental advancements in desalination science and engineering. The focus is on novel materials and hybrid treatment processes that move beyond commercially available solutions. Potential areas of exploration include: Next-generation membranes, such as: Mixed matrix, carbon nanotube, graphene-based, biomimetic, or chemically and oxidant-resistant membranes. Membranes with higher thermal tolerances. Innovative manufacturing approaches, such as: Nanoimprinting and micromixer printing directly onto membrane surfaces. Non-traditional desalination techniques, such as: Robust electrodialysis. Capacitive deionization. Hybrid thermal, electrical, and pressure-driven processes. By fostering academic research into these emerging technologies, this effort aims to develop compact, efficient, and scalable desalination systems that provide a breakthrough capability for potable water production in challenging operational environments. PHASE I: This topic is for Phase I submission only. The Department of the Army will accept Phase I proposals for the cost of up to $250,000 for a 6-month period of performance. Demonstrate feasibility of the proposed treatment technology in a laboratory setting. Perform laboratory testing and evaluation of novel high recovery desalination on multiple seawater and brackish water sources. Verify the technology can meet the requirements and address potential integration issues while showing a pathway to scale to a full-size system. PHASE II: Based on the performance and design parameters elucidated in Phase I, conduct technology and component maturation as needed, then design, fabricate and demonstrate an integrated water treatment prototype demonstrator that can desalinate at a rate of 50 gallons per hour, fit in the back of a HMMVV, and treat water at an energy demand below 50 Wh/gallon. The system should be able to recovery >85% (Objective) and >75% (Threshold) of the water source. The delivered demonstrator should be suitable for controlled performance testing and field demonstration, but the design does not need to be ready for manufacturing, nor is military standard durability required. The demonstrator shall be able to treat the water sources defined above, as well as natural surface and ground fresh water sources while meeting the weight and energy metrics of a full-sized system. The product water from all sources must meet the water quality requirements of Technical Bulletin Medical 577. PHASE III DUAL USE APPLICATIONS: This technology has the potential to be utilized in commercial and municipal operations that need a way to efficiently desalinate water for potable use. REFERENCES: https://www.nature.com/articles/s44221-024-00238-1 https://nap.nationalacademies.org/read/23659/chapter/17 KEYWORDS: Water; Water Treatment; Desalination; High Recovery; Energy Reduction