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Pathogen reduction in an algal-based wastewater treatment system employing Galdieria sulphuraria
- Delanka-Pedige, Himali M.K., Munasinghe-Arachchige, Srimali P., Cornelius, Jackson, Henkanatte-Gedera, Shanka M., Tchinda, Duplex, Zhang, Yanyan, Nirmalakhandan, Nagamany
- Algal research 2019 pp. 101423
- Acidobacteria, Arcobacter, Enterococcus faecalis, Escherichia coli, algae, coliform bacteria, dissolved organic carbon, fecal bacteria, nutrients, pathogens, quantitative polymerase chain reaction, wastewater, wastewater treatment
- The feasibility of an algal-based wastewater treatment system employing an extremophilic alga, Galdieria sulphuraria, in removing dissolved organic carbon and nutrients from primary-settled wastewater has been demonstrated at pilot scale. Here, pathogen-reduction capability of this system was assessed and compared against that of an existing traditional wastewater treatment system (WWTS). While total coliform in the influent (2.3 × 107 CFU/100 mL) was reduced by 3.3 log units in the WWTS, no total or fecal coliform were detected in the algal effluent. Results of qPCR analysis confirmed 98% removal of total bacteria and complete removal of Enterococcus faecalis and Escherichia coli in the algal system. Illumina MiSeq sequencing showed diverse bacteria phyla (>10 classifications) in the WWTS-effluent; but, only two classifications in the algal effluent. Bacteria kingdom relative to the entire microbial population declined from 99% to 83% in the WWTS; and to 17% in the algal system. Proteobacteria phylum (which includes mostly putative pathogenic bacterial genera) dominated the WWTS-effluent (abundance = 35%). Substantial alteration of the bacterial profile was observed in the algal system: Acidobacteria phylum being the most dominant (98%), and Proteobacteria, the least (2%). At the genus level, enteritis-causing Arcobacter species were detected only in the WWTS-effluent with a relative abundance of 0.9%.