Pollution Prevention and Control Technologies
for Plating Operations
Section 2 - General Waste Reduction Practices
2.4 DRAG-OUT REDUCTION
2.4.2 Drag-Out Reduction Techniques
The Users Survey indicates that many devices and procedures are
used successfully to reduce drag-out. These techniques usually
are employed to alter viscosity, chemical concentration, surface
tension, velocity of withdrawal, and temperature. Also used are
drag-out tanks and similar equipment for capturing lost plating
solution and for returning it to the bath.
Most drag-out reduction methods are inexpensive to implement and
are repaid promptly through savings in plating and processing
chemicals. An additional savings many times the cost of the changes
is realized through decreased operating costs of a pollution control
system. The reduced drag-out will decrease the need for treatment
chemicals and, subsequently, the volume of sludge produced.
For some process solutions, return of drag-out may be impractical.
In the case of processing baths which become steadily contaminated
by use, the return of drag-out would simply increase the frequency
of dumping (ref. 305). For example, PS 116 reported that drag-out
recovery with electropolishing was ìcounterproductive.î
The following subsections provide further detail and discuss the
results of the Users Survey with respect to drag-out loss prevention.
A summary of the Users Survey data relating to drag-out loss prevention
is presented in Exhibit 2-10. As with the good operating practices,
there is a high usage rate of these pollution prevention methods
among respondents and all of the methods have received a success
rating above the mid-point of the rating scale.
18.104.22.168 Minimizing Drag-Out Formation
22.214.171.124 Direct Drag-Out Return
126.96.36.199 Drag-Out Recovery and Return
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