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Abstract:
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This thesis, "An Investigation into the Development of
a Hethodology for Effluent Color Measurement," was initiated
because of a need for further information about a proposed
instrumental test method for effluent color determination.
The American Dye Manufacturers Institute (ADMI) method was
selected by the Environmental Protection Agency as the method
to be used for the determination of effluent color, and
proposed federal standards for effluent color were given in
ADMI units. The ADMI method is intended to replace the
currently standard APHA (American Public Health Association)
method of color measurement which is based on the visual
assessment of the color depth of a sample compared to a
standard solution of chloroplatinate ion.
A laboratory investigation made using five hues of
direct dye at five levels of concentration indicated the ADMI
method was applicable to all hues, but the instrumental
method of tristimulus values determined for the sample
exerted a significant influence on the resultant ADMI color
values when tested at the 95 percent confidence level.
An investigation was made of the use of (l00-Y) as a method of effluent color determination. Results indicated
this method was also sensitive to the method of tristimulus Y
value determination and was not applicable to all hues.
An investigation of the influence of turbidity on the
perceived color depth of a solution indicated that increased
turbidity will result in increased apparent color depth for
all hues examined. This observation indicated that if the
rationale for effluent color regulation is aesthetics, then
sample turbidity must be considered because of its influence
on apparent color depth.
The units of color for the currently standard APHA
method of color assessment were found to be equivalent to the
ADMI color units only for the hue which closely corresponded
to the standard chloroplatinate solutions. For hues different
from the light yellow standards, the magnitude of color
differences varied. consequently, it was concluded that the
visual comparison method was not applicable to all hues, and
the ADMI method was well suited to effluent color measurement
when accurate determinations of tristimulus values for the
samples were made.
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