Section 8. EXPLOSIVE WASTES
REMOVAL OF EXPLOSIVES FROM LOAD-ASSEMBLE-PACK
WASTEWATER (PINK WATER) USING SURFACTANT TECHNOLOGY
Donald J. Freeman, Chemical Engineer
Olin A. Colitti, Project Leader
Large Caliber Weapon Systems Laboratory
U.S. Army Armament Research and Development Command
Dover, New Jersey 07801
INTRODUCTION
Previous work on the Pollution Abatement and Environmental Control Technology
Program under Research and Development Project No. 1L76270D048 administered by
the Chemical Systems Laboratory, ARRADCOM, demonstrated the feasibility of using
surfactants to remove explosives dissolved in water [1,2]. The explosives of concern were
TNT and RDX, the ingredients of Composition B explosive, since these have been discharged
in large quantities in the wastewaters from both explosive manufacturing and ammunition
loading plants in concentrations of approximately 120 and 25 mg/l, respectively. Although
improvements in the manufacturing processes and decreased production levels during the
past few years have drastically reduced the amount of TNT and RDX being discharged, the
amount still remains significant. Photolysis products of the dissolved TNT are the compounds that cause the well-known pink water discharge, which is aesthetically, as well as
environmentally undesirable.
Both TNT and RDX are toxic. Aquatic organism and mammalian toxicities of TNT in
water are 60 and 44 /L(g/1, respectively, while those of RDX in water are 300 and 34 Lig/\,
respectively. TNT and RDX both yield positive Ames test results that are indicative of
potential mutagenic-carcinogenic properties. Effluent guidelines of 10 /ig/1 for TNT and
30 /ig/1 for RDX have been proposed by the U.S. Army Medical Bioengineering R&D
Laboratory to the Surgeon General, even though the methods to reliably measure these low
concentrations are still being developed. Neither TNT nor RDX are biodegraded under normal conditions in the environment or in biological waste treatment facilities. There is some
evidence that RDX is biodegraded slowly under anaerobic conditions, while TNT is bio-
transformed into amine complexes that are even more toxic than the original explosive
[3]. Although these substances may be removed from wastewaters using carbon adsorption,
the basic process is expensive and there is an added expense for regeneration of spent carbon
or environmental problems associated with the disposal of the explosive-laden spent carbon.
Two types of surfactants have been demonstrated to be effective in the precipitation of
TNT from solution. One was a surfactant in which the polar group was a primary amine
while the other was a quaternary amine. The precipitation of TNT from solution is the result
of the reaction between TNT and the surfactant in an alkaline medium to form an intermediate substance identified as the Janovsky complex [1,2] that, in turn, reacts with the
protonated surfactant and precipitates as a salt:
Janovsky  Complex
H02