Thesis Details

Thesis Title: An investigation into the development of a methodology for effluent color measurement
Thesis Author: Charles Simmons
Abstract: 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.