Performance evaluation of cyanobacteria removal from water reservoirs by biological method

With the rapid growth of urbanization, the discharge of industrial, agricultural and municipal wastewater into water resources is increasing. Cyanobacteria are a dominant component of the phytoplankton that causes problems in water reservoirs. The aim of this study is to evaluate the performance of bacteria in the removal of cyanobacteria algae from water reservoirs. In this study, a biological method with four types of bacteria was applied for algae removal. First of all, species of cyanobacteria were identified, and then their specific medium BG-11 was prepared. The species of bacteria (Pseudomonas aeroginosa, Enterobacter aerogenes, Klebsiella oxytoca, and Citrobacter freundii) were used for removing cyanobacteria for a period of 0 to 10 days. Variables such as chlorophyll a, nitrate, phosphate, dissolved oxygen, heterotrophic plate count, and algal cell count were measured during the study period. The results of the present study showed that P. aeroginosa and C. freundii were effective for the removal of chlorophyll a in the first five to six days of the study period with removal efficiency of 63.5 and 56.59% respectively. The other parameters such as phosphate, nitrate, and algal cells decreased relatively. This method is relatively efficient and effective for removing algae from water resources and can be used for removing nutrients and cyanobacteria algae from water resources.     Key words: Algae, biological, biotechnology, cyanobacteria, water.