Determination of Colority of Sewage Water

As a modification for the conventional method,determination of colority of sewage water was improved by using spectrophotometry instead of the visual colorimetry,and using a dil. H2SO4 solution (ca. 0.02 mol·L-1) of K2Cr2O7 and CoSO4 as standard solution for preparation of standard cuve. Measurement of absorbance was made at the wavelength of 350 nm,which is the absorption maxima of the standard solution. A linear standard curve covering colority between 10° to 100° was prepared. Factors influential to the determination (i.e. temperature,turbidity and acidity of the water sample) were studied. Detection limit of this method was found to be 5°.