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Field Verification of Micro/Ultra Filtration


TECHNOLOGY AREA(S): Human Systems 

OBJECTIVE: Design a novel approach and deliver a device that will verify micro/ultra filtration for expeditionary water purification systems. 

DESCRIPTION: The Army seeks a simplified, real-time, inline monitoring of product water from military mobile water treatment systems to verify low pressure water treatment processes to enable the Army to accomplish two operational energy mission objectives: 1) allow easy scale down of water treatment systems for use in expeditionary water supply operations, and 2) reduce the fuel required for water treatment of stable, fresh water sources (i.e. allow by-pass of the reverse osmosis treatment). Since the required application is process control, identification is not as important as the knowledge that potentially viable microorganisms made it through treatment processes that were designed first to exclude them by size and then to disinfect them. Objectively, a small size configuration would support special operations that may prefer to exploit water sources with limited or no purification, however, most purification equipment will have its own generator and not be of man-portable size. The technical approach must lead to a device that is rugged and supportable in remote areas worldwide. The best approach uses sensor measurements or measurement techniques that have not been applied to water monitoring. Real-time can be considered less than 1 hour, however, time and sensitivity are relative to the best available performance for the information the device will provide, for example, it is a significant achievement to certify less than 1 e. coli per 100ml in less than 8 hours. 

PHASE I: Demonstrate feasibility of measurement algorithm comprising a statistically robust number of samples of tap water spiked with a pathogen surrogate relevant to your measurement method. Verify measurement precision and repeatability by comparing the results to analysis conducted using the appropriate reference method from the current edition of Standard Methods for the Examination of Water and Wastewater (i.e. send some duplicate samples out for individual analyses by a commercial water test lab). Analyze to estimate operating cost per hour assuming device used 20 hours per day. Perform analysis and test to address any fundamental environmental and transport durability issues for the proposed design. Perform analysis and test to determine expected precision/sensitivity and time per measurement. 

PHASE II: Deliver a complete sensor prototype or a probe (subsystem) that can integrate into existing commercial and military sensor suites to complete a sensor prototype. The sensor prototype should be capable of communication with an external data logger. Delivered prototype must be suitable for 3rd party and Army laboratory testing and field demonstration, but design does not need to be finalized, nor is military standard durability required. Clear operational manuals do not require military format. If choosing to integrate the probe (subsystem) into an existing military sensor suite, assume the military will perform integration. Test integrated prototypes to the criteria of Phase I with standard preparations and collected water and with both surrogate materials and real pathogens. 

PHASE III: Final solution is a quick-connect autonomous inline system but a kit that accepts batch samples may be suitable. The sensor platform should be self-calibrating with duration of at least one month before recalibration is needed. The most supportable design would utilize commonly available supplies, common communication protocols and not directly interface with the controls of the water purification system. The Army can integrate the technology developed under this STTR into the mobile water purification systems being developed to answer Acquisition requirements and upgrade current systems. Water utilities could insert the technology developed under this STTR in facilities to improve quality control. 


1: U.S. Army Public Health Command - TB MEDD 577 SANITARY CONTROL AND SURVEILLANCE OF FIELD WATER SUPPLIES Note: This fully explains all field military operations that concern this topic author.

2: Standard Methods for the Examination of Water and Wastewater, a joint publication of the American Public Health Association (APHA), the American Water Works Association (AWWA), and the Water Environment Federation (WEF). Note: This reference is the benchmark for all analyses and source of approved methods for regulatory compliance.

3: Complying with the Safe Drinking Water Act", US Army Public Health Command Technical Guide 179. Available to public online at: Note: section 4.4 Microbial Contaminants refers to military and civilian overlap.

4: Filtration in the Use of Individual Water Purification Devices," US Army Public Health Command Technical Information Paper #31-004-0211. Available to public online at: Note: This is an excellent primer of filtration processes.


KEYWORDS: Water, Water Quality Monitoring, Pathogen, Filtration, Water Purification, Sensor, Microfiltration, Ultrafiltration 

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