Estimation of algae concentration in water solutions using spectrophotometry measurements and absorbance first derivative

Abstract

The monitoring and detection of algae in wastewater and surface solutions is important in controlling the quality of surface water and wastewater, yet there is currently no quick and simple method to achieve this. The present work illustrates a new method to determine the concentration of algae in different water samples using spectrophotometric measurements and the absorbance first derivative. The relationship between algal concentration and absorbance for three types of water solution (distilled, surface, and wastewater) was established in the 200-800 nm wavelength range, and the effect of using the absorbance first derivative on improving algal concentration detection limit was estimated. In the distilled water samples, the lowest detection limits, using absorbance measurement and the absorbance first derivative, were 0.53 mg TVS/L and 0.47 mg TVS/L, respectively. In samples collected from surface water and wastewater treatment plants, the detection limits varied between 0.56 to 3.84 mg TVS/L depending on the NOM in the water sample. Higher detection limits were possible with the chlorophyll extraction methods.