TM 5-814-8
maintenance, spray booths, radiator cleaning and
compounds in the associated wastewater. Older
paints are removed by strippers containing
floor wash. Engine cleaning is frequently per-
mostly methylene chloride and hexavalent chro-
formed with a decreasing agent in conjunction
mium with additional surfactants, thickening and
with steam and detergent cleaning or, in modern-
wetting agents. High levels of lead compounds
ized facilities with high-pressure hot water, elimi-
can be expected when stripping lead based paints.
nating solvents and detergents. Although most
Viable treatment alternatives for phenolic waste
spent oils are recycled, spills in engine mainte-
include hydrogen peroxide oxidation and/or car-
nance areas are frequently sent to floor drains.
bon adsorption.
(b) Scheduled maintenance platforms (SMP)
(10) Metal plating. Metal plating process
have been provided to modernize some facilities.
wastewater is defined as all waters used for
These will be covered to minimize wastewater and
rinsing, alkaline cleaning, acid pickling, plating
will include oil removal. High-pressure hot water
and other metal finishing operations; it also
has replaced steam cleaning, eliminating use of
includes waters which result from spills, batch
solvents and detergents.
(6) Laboratories. Hospital laboratories usu-
dumps and scrubber blowdown. The cleaning,
ally incinerate pathological solid and semi-solid
pickling and processing solutions may contain a
variety of chemical compounds, most of which at
waste products. Liquid waste may be disinfected
very low concentrations have a toxic potential to
prior to discharge to the sanitary sewer. X-ray
aquatic life. At higher concentrations, they may
and photographic laboratories commonly pretreat
also be toxic to humans. The suspended solids
fixing solutions to recover silver prior to dis-
charge (DOD Div. 4160.21-M). X-ray finishing
concentration is elevated due to components such
as precipitated metal hydroxides, tumbling and
and washing solutions are discharged directly to
burnishing media, metallic chips and paint solids.
the sewer.
Treatment methods commonly used include batch
(7) Laundries. Laundry washwaters are a sig-
nificant source of BOD and flow. Wastewater is
treatment for cyanide destruction, continuous
flow-through treatment for cyanide and chromium
usually filtered through a lint screen and some-
contaminated rinse waters and an integrated
times cooled for heat recovery prior to discharge
treatment system for cyanide and chi-omit acid
into the sewer. Dry cleaning solvents are nor-
process solutions. Lime precipitation can be used
mally recycled but a small volume may enter the
for the removal of other metals. When clarifica-
sanitary sewer system.
tion of the treated rinse water containing precipi-
( 8 ) Coa l pile r u n o f f . C o a l p i l e ru n o f f
tated metal hydroxide is required, it normally is
wastewater results from the passage of water
accomplished with settling tanks or clarifiers or
through coal deposits where disulfides, usually
filtration using pressure filters.
pyrites, are exposed to the oxidizing action of air,
(11) Munitions manufacturing. Propellants
water and bacteria. Coal piles exposed to air and
and explosives are materials which, under the
moisture will result in sulfide oxidizing to ferrous
influence of thermal or mechanical shock, decom-
s u l f a t e (copperas) (FeS0 4) and sulfuric acid
pose rapidly and spontaneously with the evolua-
(H2SO4). The major characteristics of this runoff
tion of a great deal of heat and much gas. Some
flow include a high suspended solids concentra-
of the most common industrial and military
tion and turbidity, mainly from coal, a low pH
propellants and explosives include gunpowder,
and high H2SO4 and FeSO4 concentrations. Major
nitrocellulose, nitroglycerin, ammonium nitrate,
treatment and disposal methods involve settling,
trinitrotoluene (TNT), picric acid, ammonium picr-
froth flotation and drainage control.
ate, RDX, HMX, and lead azide. When these
(9) Paint stripping. There are several paint
compounds are manufactured, the associated
stripping methods in use today: mechanical,
wastewater is an acidic, odorous flow sometimes
chemical or molten salts. Chemical or solvent
containing metals, organic acids and alcohols, oils
stripping uses either a hot or a cold method. Cold
and soaps. Major treatment methods include
strippers may be further classified by material
flotation, chemical precipitation, biological treat-
used into:
ment, aeration, chemical oxidation neutralization
Organic solvents.
and adsorption.
Emulsion type.
Acid type.
3-4. Comparison of domestic and in-
Combination of types.
dustrial wastewaters
Organic solvent stripping processes of modern
a. Composition and concentration. All waste-
paints, involving spray-on/spray-off stripping pro-
waters differ in composition and concentration.
cedures, have exhibited high levels of phenolic
3-9
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