TREATMENT OF WASTEWATER CONTAINING
NITROGLYCERIN AND NITRATED ESTERS
Robert P. Carnahan, Deputy Chief
Petroleum & Environmental Technology Division
U.S. Army Mobility Equipment Research & Development Command
Fort Belvoir, Virginia 22060
Leonard Smith, Senior Process Engineer
Hercules Corporation
Wilmington, Delaware 19899
INTRODUCTION
Due to the Federal Water Pollution Act and its recent amendments, the U.S. Army is
engaged in an extensive modernization and pollution abatement program at all of is   ammunition plants.   The treatment of wastewaters containing explosives such as nitroglycerin
and nitrate esters has been of particular concern.   For example, at Radford Army Ammunition Plant the wastewater discharged from the manufacture of nitroglycerin is 36,000
gal/day at a production rate of 17,000 lb/day of nitroglycerin.   This wastewater contains
approximately 3600 pounds of dissolved solids, of which 210 lb are nitrate/nitrite/nitrogen
and 47 lb are nitroglycerin [1].   Epstein era/. [2] also confirmed these figures but also
found the glyceryl mononitrate and dinitrate as well as carbonyls.
The pollution abatement problems associated with nitrated esters, structures of which
are shown in Table I, are to eliminate the explosive potential of the waste and produce a
waste which can be discharged or further treated biologically.   In solving these problems a
review of the literature was made to determine what processes were the most industrially
feasible.   Results of this review showed that alkaline hydrolysis with lime, oxidation with
ozone, permanganate or dichromate, and reduction with sodium sulfide were feasible processes.   Each of these processes were evaluated in bench-scale studies by Smith and
Dickenson [3].
Smith and Dickenson [3] results showed that alkaline hydrolysis with lime and reduction with sodium sulfide were the most effective denitration processes.   Their results
showed that if the pH was maintained at 11 the hydrolysis of the glycerol dinitrate (DNG)
and glycerol trinitrate (NG) was complete in 30 min.   With an average alkalinity of 4600
mg/1 it was estimated that 20 lb of lime per 1000 gal of wastewater was sufficient to complete the denitration step.
Their results [3] also substantiated Boschen, et al. [4] work which showed that at
pH 13 the mechanism for reduction was nucleophillic attack by the sulfide on the nitrogen.   They found that 0.71 lb of sodium sulfide was required to denitrate one pound of
NG, while 0.43 lb was required to denitrate one pound of DNG.   This compared favorably with the theoretical requirements of 0.52 and 0.43.
In oxidation studies [3] the economics of using permanganate, dichromate and ozone
were prohibitive.   For example, 2.8 lb of ozone was required to oxidize one pound of
NG.
Based upon the literature review and bench-scale studies a pilot plant using sulfide reduction and alkaline hydrolysis was constructed at Radford Army Ammunition Plant.   The
reduction process was used to treat the nitrated esters wastewater, while alkaline hydrolysis was used to treat NG and DNG wastewaters.   The flow sheet for the pilot plant is
shown in Figure 1.
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