CHARACTERIZATION OF THE IMPACT OF COLORED WASTEWATERS
ON FREE-FLOWING STREAMS
Alan J. Anthony, Director
Industrial Division
Bureau of Applied Technology
State Water Control Board
Richmond, Virginia 23230
INTRODUCTION
A study to characterize the impact of colored industrial wastewaters on free-flowing
streams was undertaken in Virginia during the summers of 1975 and 1976.   The qualitative examination of a receiving stream for the presence of industrial waste contamination
for color is a rather simple determination, whde the quantification of the extent of the
discoloration is an entirely different matter.   The driving force behind the study to determine an accurate and reasonable method of measuring color was basically twofold.   First,
numerous citizen complaints have been received in the recent past over what they felt
were unaesthetic conditions in certain streams which receive colored wastewaters.  The
Commonwealth of Virginia's Water Quality Standards, specifically the General Standard,
state that the waters of the Commonwealth shall be free of substances attributable to
sewage or industrial discharges, including color.   Therefore, if a citizen of the Commonwealth feels that he has noticed a color problem in the state's waters, there is a possible
violation of the water quality standards.   The second reason is Public Law 92-500, which
among other requirements specifies that water quality standards shall be attained by July
1, 1977, including by definition the General Standard in Virginia, therefore a time limit
was established.   In summary, it was decided that a study would be performed to compare the Platinum Cobalt and American Dye Manufacturers Institute techniques of analysis for color measurement to determine within each technique's limitations which was the
most accurate and reasonable approach for the quantification of color.
PHYSICAL STUDY AREAS
The study areas examined were confined to relatively small receiving streams.   For
example, the 7-day consecutive, 10-yr drought flows for the receiving streams in question
range from about 35 ft /sec to essentially zero flow without the industrial discharges.
The industrial categories included in the study program were the dyeing of tufted carpets,
vegetable and chrome tanning, dyeing of pile materials, and dyeing of knitted fabrics.  In
addition, each of the colored industrial wastes received before discharge the equivalent of
best practicable treatment for their inherent BOD5 and total suspended solids (TSS)
parameters.
TECHNIQUES OF ANALYSIS
The analysis techniques for color determination that were used in this study were the
Platinum Cobalt [1] and American Dye Manufacturers Institute [2] procedures. Before
obtaining the spectrophotometric results two steps were performed on the samples. First,
the samples were filtered; therefore the color results should be interpreted to represent
true color rather than apparent color. Second, all the samples were adjusted to a pH of
7.6 in order to ensure that a standard pH was employed for the analysis, since color has
been reported to be very sensitive to pH changes.
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