Correlation among indicators in regulating colored industrial wastewaters

Color indicators for industrial effluents, including the transparency (TRA) , dilution ratio (DR), ADMI tristimulus filter (ADMI) and Lavibond unit (LU ), are adopted in many countries. The aims of this study were to (1) invest igate the effects of suspended solids (SS) and color on the TRA values, (2) study the effects of water sample pH and pore size of filter papers on the color values, and (3) evaluate the relationships among these color indicat ors. Results showed that the TRA measurement is markedly affected by both t he hues of color and SS. For an effluent of the same TRA value, the ADMI va lue ratio varied by a factor of 2 to 50. This implies that TRA is not a sui table indicator in quantifying the effluent color strength. The pare size o f filter papers affects the ADMI values more than the water sample pH does. Furthermore, although the TRA does not correlate to any of the other three indicators, i.e., DR, LU or ADMI, the statistical analysis from both synth etic and real colored effluents shows that there exists a high correlation among DR, LU and ADMI values. The information presented in this study enabl es the conversion of color value from one country (area) to another dependi ng on the color indicator adopted. (C)1999 Elsevier Science Ltd. All rights reserved.