(a) Waste reduction. Waste reduction prac-
tal impacts of LAP wastes include red coloration
from TNT-containing wastewater, heavy metal
tices which should be evaluated include use of
counter-current flow of successive rinse waters,
toxicity, oxygen depletion and toxicity and bitter
separation and reuse of lightly contaminated
tastes from excess nitrates (11)(20).
water (such as cooling water), elimination of
(c) Treatability. LAP plant wastes have
batch-dumping of processing solutions, recovery
been treated successfully by diatomaceous earth
and reuse of metals and pickling liquor, and
filtration followed by activated carbon adsorption.
provisions to divert highly contaminated spills to
Effluents of less than 5 mg/L of TNT are readily
holding tanks for individual treatment.
attainable. Suspended solids removals by the
(b) Gaging and sampling. Due to the ex-
diatomaceous earth filters have, in some in-
stances, been much less than expected. Presence
treme variations in flows and characteristics en-
countered, careful sampling and gaging proce-
of suspended solids in waste entering the acti-
vated carbon filter greatly reduces the effective
dures must be employed in order to characterize
life of the carbon unit due to clogging. Normally,
the waste and identify peak values. Identification
the spent carbon is burned, although experimen-
of peak values is helpful in tracing batch dump-
ing and is essential to cost-effective design of
tal work is being performed to determine the
feasibility of regeneration in fluidized beds. Car-
bon usage varies from 2 to 7.5 lb carbon/1000 gal
(c) Environmental impact. The environmen-
tal impact of metal working wastes can be acute.
(11)(20). Plating wastes from renovation opera-
Heavy metals, acids, surfactants and oils are all
tions are treated in the manner described in
highly toxic to aquatic life. Serious stream degra-
c. Metal plating. The major waste sources are
dation results from the direct discharge of insuffi-
rinse water overflow, fume-scrubber water, batch-
ciently treated metal wastes.
(d) Treatability. Toxic materials present in
dumps of spent acid, alkali, or plating bath
solutions, and spills of the concentrated solutions.
the wastewaters from munitions metal parts man-
(1) Plating waste separation. Processing solu-
ufacturing can interfere with biological treatment.
Treatment methods available include neutraliza-
tions are often replaced on an intermittent basis;
tion with lime, heavy metal removal and recovery
consequently, dumps of spent solutions impose a
heavy short term load on treatment facilities.
Therefore, separate collection of waste process
by gravity separation. Suitably pretreated wastes
will be cost-effectively treated along with domes-
solutions and rinse waters should be evaluated.
Separation as to type of waste is also desirable to
facilitate later treatment and to avoid the produc-
(3) Loading, assembling and packing wastes.
The main LAP operations are explosives receiv-
tion of the toxic hydrogen cyanide gas at low pH
levels. Categories for waste separation are as
ing, drying and blending operations, cartridge and
shell-filling operations and shell-renovation. The
main waste sources are spillage, cleanup water,
--Oil bearing wastes from cleaning opera-
dust and fume scrubber water and waste flows
--Acid wastes including waste pickling li-
from renovation operations.
(a) Waste reduction. Waste reduction which
quor, acid-plating solutions, and anodiz-
should be considered in a pollution control pro-
--Alkaline wastes including cyanide-plating
gram can be accomplished by reuse of lightly
contaminated water for air-scrubbing and shell-
(2) Waste reduction practices. There are a
washout. In the shell-loading operation, the use of
number of waste reduction practices which can be
covered hot water baths and shell-loading funnels
effective and should be considered for plating
operations including: dragout reduction, process/
of the water baths. High-pressure water sprays
c h e m i c a l changes, a n d good housekeeping
can reduce the amount of water used for cleanup.
(a) Plating waste dragout reduction. Reduc-
operations reduces the waste load and is an
ing the dragout from chemical baths not only
economic incentive. Proper wastewater gaging
and sampling practices can be quite helpful in
water, but it also prolongs the life of the chemical
identifying the source of any unauthorized batch-
bath. Some dragout reduction practices which
dumps and lead to waste reduction practices.
should be evaluated are:
(b) Environmental impact. The environmen-