Title: Municipal wastewater treatment as an environmnetal pathway for engineered nanomaterials (ENMs) from consumer products

Nick Voulvoulis

Imperial College London, UK


Nick Voulvoulis is Professor of Environmental Technology at Imperial College London. Nick specialises in environmental management, where science and engineering interface with public policy. 
His research focuses on environmental quality management, regarding environmental systems and processes across many diverse areas, including: societal impacts, community participation and links between research and environmental behaviour.
• Exploring the potential of systems thinking in water policy (GLOBAQUA)
• Investigating the fate of nanomaterials during wastewater treatment (NANORISK)
• Developing tools to address conflicting demands in the water-energy-food nexus (Anglian Water research programme)
• Delivering options for “closing the loop” in resources management (Veolia research programme)


The exponential growth of the nanotechnology industry and use of Engineered Nanomaterials (ENMs) in everyday consumer products have raised concerns about their potential entry to the environment and associated impacts.  Little is known about the fate, transport and transformation of ENMs from consumer products after these are used or disposed, and their potential entry to the environment. Their main pathway is through water during use or disposal down the toilet or sink to wastewater. The presence and level of wastewater treatment (WWT) available determines their potential to enter the environment. Therefore, understanding their levels in municipal wastewaters and their fate during WWT can help us predict their concentrations in the environment.  In this paper, a site-specific model for predicting environmental concentrations (PECs) of ENMs is presented. The quantities of ENMs used in consumer products, the type of application, reported values of per capita wastewater flow, the extent of removal and degradation in wastewater treatment systems, and estimates of the factors by which wastewater sludge is amended in soil and effluent is diluted in receiving streams were considered in the model. The model was developed using data from wastewater treatment plants in Northern England, UK and was then used to predict environmental concentrations of Ag, ZnO, TiO2 and CeO2 nanoparticles at selected sites. The predicted environmental concentrations were compared to data provided by the British Geological Survey (BGS). The use of these estimates in environmental risk assessments is discussed, as well as assumptions and limitations.