Wastewater Color – How to Use Color to Test Wastewater

The color of wastewater is an important indicator of the type and the nature of the effluents in it. In this article I reveal how wastewater color can be employed to identify the effluent and determine the right treatment methods.

The color of the wastewater is an indication that it contains contaminants of different materials and in varying concentrations. Some of these materials are chemical in nature. These are mostly industrial effluents discharged from factories. In such cases, the metallic ions present in these effluents impart different colors and in different hues depending on their strength and polluting potential.

The other types of effluents in wastewater that impart color to it are organic in nature. These can be peat materials, different types of weeds, and humus. Plankton which can be present in large quantities can color the wastewater.

Another reason behind the coloration of wastewater is an increase in the value of the pH of the wastewater. Hence wastewater treatment chemistry makes use of the wastewater color to identify and then apply the right treatment method. For example, when comparing samples of wastewater with color charts, a colored sample that is used, is made by combining COCL2 and Potassium Chloroplatinate. The results are usually divided between True Color and Apparent Color.

True Color:

Wastewater color that is obtained after the suspended particles have been filtered is called as True Color. Technically it is the color of non turbid wastewater.

Apparent Color:

When the color of the original wastewater sample is considered, then it is called as the Apparent Color. This sample is taken from wastewater that has not been filtered or of the sample that has not been subjected to a centrifugal force to separate the suspended contaminants.

The effluents discharged from industries which are mostly in the form of colloidal solutions as well as suspended particles, is the principle reason the industrial wastewater is colored. Hence to treat this industrial effluent, both the Apparent Color and the True Color test results are considered.