The Naval Facilities Engineering Command, through its Engineering Service Center (ESC) and Engineering Field Activity are showing their commitment to ensure environmental excellence by demonstrating new and innovative technologies. This technical data sheet focuses on a thermochemical process that mineralogically converts hazardous wastes [asbestos-containing material (ACM) contaminated with polychlorinated biphenyl's (PCBs)] to inert stable non-hazardous material. A demonstration of this technology at the Puget Sound Naval Shipyard (PSNS) is the result of a congressionally mandated BAA award. Asbestos Recycling Inc. (ARI) of Kent, Washington developed this technology and is partnering with PSNS to demonstrate it for the Navy.

Technology Description - The Navy is required to properly dispose of hazardous PCB-ACM waste generated from facility abatement and ship maintenance and repair projects. This complex problem is solved using heat and spraying the waste with an alkaline mineralizing agent to convert PCB impacted ACM into non-hazardous material. The waste reduction is significant, a reduction of approximately 90%. Most importantly, cradle-to-grave, liabilities associated with PCB-ACM are terminated, all regulated wastes are consumed. The thermochemical process is a cost effective environmentally feasible alternative to landfill disposal, endorsed by the United States Environmental Protection Agency (EPA). The PCB-ACM Conversion System meets all requirements of the National Emission Standard for Hazardous Air Pollutants (NESHAP) for asbestos conversion processes (40 CFR 61.155) and complies with (29 CFR 1910) OSHA Health & Safety Standards. An integral part of the permitting process includes an EPA-approved demonstration test burn at PSNS. All operating parameters defined by Federal, State and local permits for PCB-ACM processing are monitored and reported via a programmable logic control system developed specifically for this project. An independent emissions testing company validates destruction removal efficiency.

Project Description - Currently, the PCB-ACM Destruction Mobile Unit is contained within two transportable trailer units, approximately 45 feet long. The operations trailer is a negative air chamber vented through HEPA filters. While a secondary combustion chamber and afterburner are housed in a separate trailer. This first generation prototype will illustrate the capabilities of the technology and acquire the additional data necessary to develop and construct permanent, modular units for nationwide implementation. Projections indicate that up to 900 pounds of PCB-ACM per hour can be processed through this unit.

In October to December, the demonstration test burn at PSNS will begin. Approximately 18 tons of conventional double-bagged ACM contaminated with 90% PCB transformer oil will be processed. The process involves loading steel bins containing 5 cubic yards of bagged PCB-ACM into an interlock holding area, placing the bins onto a transfer conveyer, discharging the waste into a rip shear shredder, and reducing waste to a diameter of less than one inch. The waste is then dropped into a blender-mixer screw conveyer where an aqueous alkaline mineralizing agent is sprayed over the PCB-ACM. The waste is then transferred to a rotary hearth converter. Within the converter, electric heating elements heat the waste to temperatures of 2000 F to 2350 F. Typically the ACM is exposed for approximately 20-60 minutes. The end product, PCB-ACM free material is removed from the hearth, cooled, de-watered, and transported to holding bins. Bins are removed without breaking trailer air seal integrity. Any gases generated from the process are passed into a secondary combustion chamber. The chamber promotes mixing of combustion air with the converter exhaust gas products. The exhaust is more fully oxidized by passing through an afterburner held in an operating range of 2200 F to 2450 F. Exhaust gas exiting the afterburner is then quenched with potable water converting the end product temperature of 2300 F to 2500 F in less than a second. Gas leaving the quencher enters the acid gas absorber chamber followed by particulate removal in a venturi scrubber.