The Army decided on a course of incineration of chemical weapons more than a decade ago. At that time, it claimed that alternative technologies were poorly developed and not demonstrated to be effective.
Under congressional mandate, the Army is reviewing once more alternatives to incineration. In a report issued in 1995, the Kentucky Environmental Foundation described the five alternatives that the Army has chosen to study further. Here is a synopsis of each, based on the KEF report:
Chemical neutralization. This involves a simple process of breaking down the chemical agents through use of common, low-cost industrial chemicals, usually in a solution of water. The downside of this is it use of lots of water and may produce substantial volumes of residual waste that have to be further treated.
Chemical neutralization and biodegradation. As described by the Kentucky Environmental Foundation, this involves the same processes used in chemical neutralization, but the biodegradation step is added as a post-neutralization treatment step.
The Silver II electrical process. In this process, similar to that used to produce chlorine, waste is progressively added to nitric acid in the cathode compartment of an electrochemical cell, while the anode compartment is filled with silver nitrate dissolved in nitric acid. An electric current is passed through the cell, generating silver ions that oxidize the waste material.
The cost of this approach is estimated to be around 30 percent of incineration. Working systems could be available and demonstrated within one to three years, KEF states.
The Eco-Logic gas-phase reduction process. According to KEF, this type of treatment is occurring already in Australia, where it is used to destroy pesticide wastes. The technology “depends upon the gas-phase reduction reaction of hydrogen with organic wastes to produce methane gas” and “operates in a closed loop recirculating mode.” KEF notes that the process has not yet been demonstrated on the explosive components of chemical weapons. The U.S. Navy has undertaken a study on the effectiveness of this technology to destroy VX and HD.
Drawbacks to this approach are that it does produce emissions and other waste. In addition, it does not destroy the metal components of chemical weapons. To address the metal components, a Thermal Desorption Unit (TDU) heated by molten metal has been proposed. In tests conducted by the Environmental Protection Agency, however, “the TDU did not perform according to specification.”
The M4 Molten Metal Process. In this alternative, materials “are introduced into a bath of molten metal held at a temperature of 2400-3200 F,” KEF writes. “The technology originated from the steel industry, where it was observed that molten metal has both solvent properties and catalytic capacity, effecting a rapid breakdown of complex organic molecules.” When certain chemicals are fed into the molten bath along with the waste, the end result can be a usable product. Gases produced can be used as fuel or feedstock.
KEF is skeptical about the claim that there are no emissions from this process. Still, it is unlikely that some of the worst products of incomplete combustion, such as dioxins and furans, would be among the emissions, since “the reducing environment in which the process takes place will tend to prevent the formation of chlorinated dioxins and furans,” along with oxides of sulfur and nitrogen.
Volume 7, Number 9 March 1997
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