Removal of <i>Clostridium perfringens</i> and <i>Staphylococcus</i> spp. in Microalgal–Bacterial Systems: Influence of Microalgal Inoculum and CO<sub>2</sub>/O<sub>2</sub> Addition
2022
Graziele Ruas | Sarah Lacerda Farias | Bruno A. B. dos Reis | Mayara Leite Serejo | Gustavo Henrique Ribeiro da Silva | Marc Árpád Boncz
Conventional biological wastewater treatment systems have a low pathogen removal capacity. Microalgae-based systems are sustainable and low-cost alternatives for wastewater treatment and are capable of removing pathogens from domestic effluents. Other microorganisms have been identified as alternative indicators of disinfection since they have greater resistance than <i>Escherichia coli</i>, either because of the formation of spores or because of other mechanisms of protection, and because they spread in wastewater treatment plants; the most important are <i>Clostridium perfringens</i> and <i>Staphylococcus</i> spp. This study assessed the influence of microalgal strains (e.g., <i>Chlorella vulgaris</i> and <i>Scenedesmus acutus</i> Meyen) and the addition of CO<sub>2</sub> and O<sub>2</sub> on the removal of <i>C. perfringens</i> and <i>Staphylococcus</i> spp. from domestic wastewater in microalgal–bacterial systems. The removal of <i>C. perfringens</i> (2.5 to 3.2 log units) and <i>Staphylococcus</i> sp. (1.8 to 2.0 log units) was higher when using Chlorella sp. inoculum. The addition of CO<sub>2</sub> and O<sub>2</sub> did not have a significant effect on the removal of pathogenic bacteria. The main mechanism of <i>C. perfringens</i> removal was by means of toxins and bactericidal substances produced by the microalgae, while <i>Staphylococcus</i> spp. removal also occurred through photooxidative processes.
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