Unravelling the removal mechanisms of bacterial and viral surrogates in aerobic granular sludge systems

Unravelling the removal mechanisms of bacterial and viral surrogates in aerobic granular sludge systems

Barrios Hernandez, M.L. (TU Delft BT/Environmental Biotechnology; Instituto Tecnologico de Costa Rica; IHE Delft Institute for Water Education)
Bettinelli, Carolina (IHE Delft Institute for Water Education)
Mora-Cabrera, Karen (Universitat d'Alacant)
Vanegas-Camero, Maria Clara (IHE Delft Institute for Water Education)
Garcia, H. (IHE Delft Institute for Water Education)
van de Vossenberg, Jack (IHE Delft Institute for Water Education)
Prats, Daniel (Universitat d'Alacant)
Brdjanovic, Damir (TU Delft BT/Environmental Biotechnology; IHE Delft Institute for Water Education)
van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)

2021

The aerobic granular sludge (AGS) process is an effective wastewater treatment technology for organic matter and nutrient removal that has been introduced in the market rapidly. Until now, limited information is available on AGS regarding the removal of bacterial and viral pathogenic organisms present in sewage. This study focussed on determining the relation between reactor operational conditions (plug flow feeding, turbulent aeration and settling) and physical and biological mechanisms on removing two faecal surrogates, Escherichia coli and MS2 bacteriophages. Two AGS laboratory-scale systems were separately fed with influent spiked with 1.0 × 10⁶ CFU/100 mL of E. coli and 1.3 × 10⁸ PFU/100 mL of MS2 bacteriophages and followed during the different operational phases. The reactors contained only granular sludge and no flocculent sludge. Both systems showed reductions in the liquid phase of 0.3 Log₁₀ during anaerobic feeding caused by a dilution factor and attachment of the organisms on the granules. Higher removal efficiencies were achieved during aeration, approximately 1 Log₁₀ for E. coli and 0.6 Log₁₀ for the MS2 bacteriophages caused mainly by predation. The 18S sequencing analysis revealed high operational taxonomic units (OTUs) of free-living protozoa genera Rhogostoma and Telotrochidium concerning the whole eukaryotic community. Attached ciliates propagated after the addition of the E. coli, an active contribution of the genera Epistylis, Vorticella, and Pseudovorticella was found when the reactor reached stability. In contrast, no significant growth of predators occurred when spiking the system with MS2 bacteriophages, indicating a low contribution of protozoa on the phage removal. Settling did not contribute to the removal of the studied bacterial and viral surrogates.

Escherichia coli MS2 bacteriophages
Nereda
Pathogens
Protozoa predation
Sanitation

http://resolver.tudelft.nl/uuid:ed8b2b7d-f309-46b3-9429-f5f55ffaf3c4

https://doi.org/10.1016/j.watres.2021.116992

0043-1354

Water Research, 195

Institutional Repository

journal article

© 2021 M.L. Barrios Hernandez, Carolina Bettinelli, Karen Mora-Cabrera, Maria Clara Vanegas-Camero, H. Garcia, Jack van de Vossenberg, Daniel Prats, Damir Brdjanovic, Mark C.M. van Loosdrecht, More Authors