Algae are a type of plant-like organisms that can make food from sunlight by photosynthesis. Although the term algae refers to a diverse group of photosynthetic organisms, from a water treatment standpoint, unicellular species are of highest concern.
WHY IS IT IMPORTANT?
In general, presence of algae in surface waters and wastewater is associated with water quality deterioration. In surface water, the presence of algae creates surface scum, poor water clarity, and noxious odours. The algae may lead to problems in the drinking water treatment process, such as reduced filter runs and an increase in the amount of disinfectant needed, which can increase the cost of the treatment. On the other hand, algae have many commercial uses, and are produced on an industrial scale for applications such as fuel, fertilizer, animal and human food, and stabilizing agent production, and as a pollution control tool.
The methods used to determine algal concentrations in water samples include algal number, as prescribed in the Standard Methods for the Examination of Water and Wastewater, and the determination of chlorophyll extract concentration in relation to total algal concentration. Alternatively, algae in water can be detected using spectrophotometric techniques ranging from fluorescence to derivative spectrophotometry.