Assessing the potential of a membrane bioreactor and granular activated carbon process for wastewater reuse – A full-scale WWTP operated over one year in Scania, Sweden

• Published in: The Science of the total environment Vol. 895; p. 165185
• Main Authors: Takman, Maria, Svahn, Ola, Paul, Catherine, Cimbritz, Michael, Blomqvist, Stefan, Struckmann Poulsen, Jan, Lund Nielsen, Jeppe, Davidsson, Åsa
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-10-2023
• Subjects: 16S rRNA gene sequencing; Bacteria; Chemical Sciences; Earth and Related Environmental Sciences; Engineering and Technology; Environmental Biotechnology; Environmental Sciences; Geovetenskap och miljövetenskap; Kemi; Metals; Miljöbioteknik; Miljövetenskap; Natural Sciences; Naturvetenskap; Organic Chemistry; Organic micropollutants; Organisk kemi; Teknik; Vattenbehandling; Water reclamation; Water Treatment; Bacteria; 16S rRNA gene sequencing; Organic micropollutants; Metals; Water reclamation
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2023.165185

A full-scale membrane bioreactor (MBR) with ultrafiltration, followed by granular activated carbon (GAC), was examined to determine the potential of reusing treated water as a source of drinking water or for irrigation. The major part of the bacteria removal took place in the MBR, whereas the GAC removed substantial amounts of organic micropollutants. Annual variations in inflow and infiltration resulted in a concentrated influent during summer and a diluted influent in the winter. The removal of E. coli was high throughout the process (average log removal 5.8), with effluent concentrations meeting the threshold for class B water standards for irrigation (EU 2020/741) but exceeding those for drinking water in Sweden. The total bacterial concentration increased over the GAC, indicating the growth and release of bacteria; however, E. coli concentrations declined. The effluent concentrations of metals met the Swedish criteria for drinking water. The removal of organic micropollutants decreased during the initial operation of the treatment plant, but after 1 year and 3 months, corresponding to 15,000 bed volumes, the removal increased. Maturation of the biofilm in the GAC filters might have resulted in biodegradation of certain organic micropollutants, in combination with bioregeneration. Although there is no legislation in Scandinavia with regard to many organic micropollutants in drinking water and water for irrigation, the effluent concentrations were generally in the same order of magnitude as to those in Swedish source waters that are used for drinking water production.
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•Wastewater reuse with a full-scale MBR and GAC process was investigated.•DNA sequencing and analysis of bacteria, metals, and organic micropollutants•Low effluent concentrations of E. coli, metals, and organic micropollutants•Drinking water quality was not achieved.•Water quality for irrigation was generally achieved.