Microwave Water Decontamination Technology

The US Army Research Office awarded SBIR Phase I and Phase II grants totaling $850,000 to CHA Corporation to develop and field-demonstrate their microwave water purification technology. This process destroys hydrocarbons, chemical and biological warfare agents in water produced from washing military vehicles at combat zones. The 2-gpm fielddemo microwave unit was constructed and transported to Camp Guernsey of the Wyoming Army National Guard and tested at both a car wash bay and a machine shop for one month in June 2005. The field demo microwave unit was then transported to the Wyoming National Guard site in Cheyenne Wyoming and operated with water produced from washing helicopters in July 2005.

After the field demonstration was complete, the microwave prototype was operated in the CHA Corporation laboratory to demonstrate the microwave ability to destroy biological agents in water. All three field demonstrations and biological tests proved successfully the effectiveness of microwave decontamination technology and produced valuable operational and performance data that has been used to modify the prototype design to develop a commercially viable microwave water decontamination system.

The US Army Research Office awarded a SBIR Phase II Plus grant of $170,000 to CHA Corporation. Enhanced Recovery, Inc. (ERI) provided $50,000 in cash and microwave equipment valued at $120,000 to CHA Corporation. Under the Army SBIR Phase II Plus program we have constructed a 20-gpm commercial demo microwave vehicle-washing system for the decontamination of combat vehicles and also for the removal of hydrocarbons from oil refinery wastewater. We installed the commercial demo microwave reactor system inside an ERI truck that houses a 915 MHz microwave generator and tested the unit at the CHA Corporation laboratory.

In January 2008 this truck housing the 20-gpm water treatment system was transported to the former Atlanta Grocery Store located at 130 Northside Dr. NW, Atlanta, Fulton County, Georgia to conduct the field-demonstration of microwave technology for ground water treatment. Dissolved gasoline constituents (benzene, toluene, ethylbenzene, and xylenes or BTEX) were removed from the siteƕs groundwater to below 1000 parts per billion (ppb) using activated carbon fabric (ACF) reactors equipped with a microwave regeneration system. It was clearly demonstrated that the ACF bed could be regenerated on site without sacrificing adsorption capacity, and that microwave silcone carbide oxidizer was capable of oxidizing BTEX desorbed from ACF bed during microwave regeneration.

During this 4-month field demonstration we processed a total of 64,200 gallons of contaminated ground water. Average influent and effluent BTEX concentrations were 28,450 ppb and 608 ppb, respectively, yielding the average DRE efficiency of 98%. The #1 ACF bed processed over 34,000 gallons of contaminated ground water and regenerated 40 times. The #2 ACF bed processed about 30,200 gallons of contaminated ground water and regenerated 30 times. The ACF beds were effectively regenerated with 3-kW of microwave power. During this demonstration period the ACF bed adsorption efficiency actually improved from 96.5% to 99%.

The test results show that microwave reactivation restored the ACF bed to the original adsorption capacity. The commercial demo unit will be field demonstrated at selected military bases and oil refinery sites in the near future. A typical de-salter at the refinery produces approximately 40gpm wastewater containing hydrocarbons including benzene. Consequently, the 20gpm microwave reactor system is considered as a commercial sized demonstration unit for treating wastewater generated at the oil refinery.