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Treatment of Powder Plant Wastes
BRUCE  W.   DICKERSON
,     " ' ,V   ' Sanitary Engineer "¦•;-..'   ' ' ^:    ./
""',:';,>. Hercules Powder Company ' ¦   • :    ;
Wilmington, Delaware - ¦
The emergency program which is being developed in this country for building up the armed forces and providing them with the sinews of war has brought Into the picture the rehabilitation of ordnance plants long since shut down. These plants were built to produce TNT, rocket powder, smokeless rifle and cannon powder and auxiliary high explosives. While they cannot be regarded as peacetime industries, their water borne wastes can be classified as industrial and treatment processes normally employed for such are applicable to many of these.
It is not within the scope of this paper to discuss the several types but to cover only those produced in the manufacture of smokeless powder.
In the plant designed to produce smokeless powder from raw cotton linters or pulp, the wastes produced can be classified in general under two types, acid and soluble organic. The sanitary waste problem is one that confronts all plants and so is not unusual. In general there is a separate sanitary se'werage system and either primary treatment or full treatment provided depending upon the local conditions.
The acid wastes comprise those from nitric and sulfuric acid manu¬ facture and the nitration of cellulose either from linters or wood pulp. The volume of waste from acid manufacture is small and the strength very dilute. The acid plants are usually so located that facilities are installed in their area for neutralization. Hydrated lime has been most satisfactory from the cost and handling angles and is preferred. Simple reaction chambers with pH control are all that are necessary to provide satisfactory neutralization. The pH Is usually held about 5.0. * The waste acids produced from nitrocotton manufacture provide the most critical neutralization problem. They comprise a mixture of sulfuric and nitric too low in concentration for economical recovery, both from installation and operational costs. Their only solution is neutralization. Flows vary widely and the total volume may be as high as, 12 MGD. Acid concentrations as H2SO4 will creep close to 1.4 per cent at maximum with .01 to .02 per cent minimum. Calcium sulfate solubilities are extremely low due to the nitric acid present, averaging between 1000 and 1200 ppm. ,  . ' .
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