Investigation and Control of Algal Grwoths in Water Resources Using Zn Oxide Nanoparticles

Increasing nutrients such as nitrates and phosphates in water resources lead to the growth of various algal species, causing undesirable odors and taste in the water. This study investigated the identification and removal of harmful algal growths by Zinc oxide nanoparticles (using Ardabil Yamichi Dam reservoir as a case study). Samples were initially collected from the Yamichi Dam reservoir and the algae in the water samples were cultivated. Enough time was allowed for the algae to grow before they were identified under the microscope. The results showed that most of the algal species grown in the culture medium belonged to the species Cladophora and Euglena. Zinc oxide nanoparticles were then synthesized to be used in the removal and/or inhibition of algal growths. ZnO nanoparticles were subsequently characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD) methods which revealed that the size of the ZnO nanoparticles was in the range of 10‒30 nanometers and further that the nanoparticles were pure and of a hexagonal phase. In continuation, the capability of ZnO nanoparticles with concentrations in the range of 0-3 ppm to inhibit algal growth was investigated. Results showed that no reduction was observed in algal growth for Zinc oxide nanoparticle concentrations below 1 mg/lit. At concentrations between 1 to 2 mg/lit, however, a significant reduction was observed in algal growth. Finally, it was found that algal growths completely stopped at ZnO concentrations beyond 2 mg/li