being plated causing dissolution. That should never happen. For
example, a chrome bath contaminated with iron can cost $20,000 to
replace. In addition, the solution is highly toxic requiring
special costly disposal, and chrome is a resource that is
difficult to obtain.
The following points should be considered:
a. For solids separation following chemical precipitation
(particularly plating waste), parallel plate or tube separators
should be evaluated. Means of cleaning plugged plates or tubes
must be provided.
b. Plate and frame filter presses have been particularly
successful for dewatering chemical sludges for direct disposal
and should be used unless special circumstances dictate otherwise.
c. Electrically powered agitators are preferred over air
spargers. Mixer shafts should be constructed of solid
corrosion-resistant materials rather than coated.
Material Selection. One of the most critical factors that has
caused unfavorable conditions at industrial waste facilities operated by
the Navy has been material selection and/or protection from the corrosive
environments. Careful selection of materials is necessary. The following
points should be considered:
a. Concrete block or masonry buildings are preferred over steel
to resist corrosion.
b. Exhaust and ventilation ductwork must be structurally sound.
Ductwork must have the proper materials to resist corrosive fumes
vented or a corrosive atmosphere on the exterior side.
c. All piping and conduit material should be resistant to the
corrosive agents and operating conditions to which it may be
exposed. All exposed metal which is nonresistant to corrosion
must be painted with a corrosion resistant paint. Effect of
corrosive atmosphere on building interior roof and walls must be
d. Tank materials (or liners) should be of proper corrosion
e. Materials for seals, connectors, and gaskets on piping and
pumps exposed to corrosive materials should be carefully selected
to avoid damage.
All pump housing should be corrosion resistant.
g. All overhead piping which carries corrosive-type materials
should be provided with a corrosion-resistant sleeve and directed
to a safe area to avoid safety hazards from 1eaky piping.
Provide emergency area floor drains.