Spectroscopy is used to describe a own family of analytical techniques, in which various frequencies (light, UV, IR, etc.) is applied to the materials to acquire spectral characteristics, or the spectra of those substances in a form of a graph.
Activated carbon, additionally called activated charcoal, is a type of carbon prepared to have little, low-volume pores that expansion the surface area accessible for adsorption or chemical reaction
G.Langergraber,et al.. (2004) stated that submersible UV/VIS spectrometer was used to monitor a paper mill wastewater treatment plant. It utilizes the UV/ VIS range (200–750 nm) for simultaneous measurement of COD, filtered COD, TSS and nitrate with just a single instrument