CATALYTIC OXIDATION OF MUNITIONS WASTEWATER
Ching-Jey Kuo, Sanitary Engineer
Wastewater Management Department, Pima County
Tucson, Arizona 85701
Raymond A. Sierka, Professor
Department of Civil Engineering
and Engineering Mechanics
The University of Arizona
Tucson, Arizona 85721
INTRODUCTION
The United States Military is a major purchaser of munitions and in the production of these munitions compounds, wastewaters are generated and eventually discharged into the environment. One of
the most serious wastewater problems is the discharge of trinitrotoluene (TNT) and cyclotrimethylene-
trinitramine (RDX), which are extremely resistant to natural biodegradation in the receiving water
and are toxic to aquatic biota.
Current treatment methods employed for TNT wastewater include neutralization, settling, filtration, biological oxidation, activated carbon and polymeric resin adsorption, chlorination, ozonation
and ultraviolet light (UV-light) in combination with powerful oxidants (e.g., ozone and hydrogen peroxide) [1]. Neutralization of acidic TNT wastewater and subsequent exposure to sunlight in settling
basins cause wastewater to exhibit a deep pink color. The treatment efficiency of biological methods
not only remains questionable but also has the disadvantage of requiring a long hydraulic detention
time to destroy the pollutants contained in the extremely large daily output of wastewater [2]. Activated carbon and polymeric resin adsorptions have been proved to be technically feasible, but the cost
of adsorbents and the difficulty of regeneration render the processes economically prohibitive.
Chemical oxidation has been proposed as possible treatment technology applicable to munitions
wastewater. Especially, sonocatalytic and metal catalytic oxidations are potentially promising as treatment methods because they have been successfully used to remove aromatic pollutants similar to those
existing in munitions wastewater [3].
OBJECTIVE
The overall objective of this research was to develop a treatment process employing Raney Nickel
Catalyst (Ra-Ni) alone or in combination with ozone for the removal of nitrobodies in munitions
wastewater, chiefly TNT and RDX.
The specific objectives of this study were as follows: (1) To quantify the effect of the Ra-Ni concentration on the rate and extent of TNT/RDX destruction; and (2) To quantify the effect of the Ra-
Ni concentration and initial solution pH on the rate and extent of TNT/RDX destruction when ozone
was employed as the oxidant.
LITERATURE REVIEW
Raney Nickel catalysts were developed originally by Mr. Murray Raney in 1925 (U.S. Patent
#1,563,587). It has widely been used for hydrogenation, amination, reduction and oxidation. Typical
reactions include the saturation of olefinic and acetylenic bonds, saturation of aromatic rings, nitrile
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